JOMO KENYATTA UNIVERSITY OF
AGRICULTURE AND TECHNOLOGY
ATTACHMENT REPORT
SCHOOL OF ELECTRICAL, ELECTRONICS AND INFORMATION ENGINEERING
DEPARTMENT OF ELECTRICAL AND ELECTRONIC ENGINEERING
ACADEMIC YEAR 2021-2022
NAME: Mike Felix Okoth Ochieng’
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REGISTRATION NO.: ENE211-0047/2018
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COURSE OF STUDY: BSc. Electrical and Electronic Engineering
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YEAR OF STUDY: 4th
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COMPANY ATTACHED: East African Breweries LTD – Kenya Breweries Limited (KBL)
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INDUSTRY BASED SUPERVISOR: John Ray Mwoya - +254723928833
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DURATION OF ATTACHMENT: 01/02/2023 – 28/04/2023
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An Attachment Report submitted to the Department of Electrical and
Electronic Engineering in partial fulfillment of the requirements for the award of a
Bachelor of Science Degree in Electrical and Electronic Engineering.
MAY 2023
ACKNOWLEDGEMENT
I take this opportunity to extend my heartfelt gratitude and appreciation to Kenya Breweries
Limited (KBL) for giving me a chance to acquire industrial skills and knowledge during my
three months industrial attachment training at their esteemed company. I express my utmost
thanks to my line manager and supervisor, Mr. John Ray Mwoya, team leaders, shift technicians
and the technical operators and the staff at KBL in its entirety for their unwavering support,
guidance, remarks and relevant suggestion throughout my training. Their tremendous support
has had a profound impact on my learning experience at the company and in the field of
electrical and electronic engineering at large.
I would also like to offer my utmost appreciation to the Almighty God for having kept me safe
and granted me good health throughout the attachment period. I would also like to thank my
family and friends for the continued support throughout the attachment period.
i
DEDICATION
I dedicate this work to my family and friends as an appreciation for their support both
financially and emotionally and their concern in my education journey.
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CERTIFICATION
This is to certify that this is report is a complete original document entailing all the works
undertaken during attachment at Kenya Breweries Limited under the supervision and direction
of Mr. John Ray Mwoya.
Mike Felix Okoth Ochieng’
ENE211-0047/2018
Signature: …………………….
Date: ………….…………………
SUPERVISOR CONFIRMATION
This project proposal has been submitted to the Department of Electrical and Electronic
Engineering, Jomo Kenyatta University of Agriculture and Technology, with my approval as
the Industry Supervisor:
Mr. John Ray Mwoya
Electrical and Instrumentation Engineer – Utilities
Kenya Breweries Limited
Signature: …………………….
Date: ………….…………………
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EXECUTIVE SUMMARY
This executive summary provides a concise overview of the Industrial Attachment Report
conducted in the Utilities Department at Kenya Breweries Limited (KBL). The report focuses
on the operations and functions of the Utilities Department, specifically in the areas of water
treatment, air plant, fridge plant, CO2 plant, and effluent treatment plant.
The report begins by highlighting the history of KBL and goes on to discuss the significance
of the Utilities Department in supporting KBL's production processes and sustainability goals.
It emphasizes the importance of efficient water management, energy conservation, and
environmental responsibility.
The air plant section details the essential role of the air plant in supplying compressed air for
production equipment. It discusses the equipment and processes involved in compressing,
cooling, and filtering air to meet the quality requirements of the brewery.
The fridge plant section explains the refrigeration system used in cooling and maintaining the
temperature of various brewery products. It describes the key components of the fridge plant,
such as compressors, condensers, and plate heat exchangers, and their functions in the cooling
process.
The CO2 plant section focuses on the production and utilization of carbon dioxide gas in the
brewing process. It discusses the role of CO2 in preserving product quality, creating
carbonation in beer, and the processes involved in capturing, storing, and distributing CO2
within the brewery.
Overall, this Industrial Attachment Report provides a comprehensive understanding of the
operations and functions of the Utilities Department at KBL. It highlights the department's
contribution to water management, air supply, refrigeration, carbon dioxide production, and
wastewater treatment. The report also covers the different electrical machines and instruments
within the department.
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TABLE OF CONTENTS
ACKNOWLEDGEMENT ..................................................................................................................... i
DEDICATION ....................................................................................................................................... ii
CERTIFICATION ............................................................................................................................... iii
SUPERVISOR CONFIRMATION .................................................................................................... iii
EXECUTIVE SUMMARY .................................................................................................................. iv
TABLE OF CONTENTS ...................................................................................................................... v
CHAPTER ONE: INTRODUCTION ................................................................................................. 1
1.1.
Brief History of East African Breweries Limited (EABL) .................................................... 1
1.2.
KBL Purpose, Ambition, Core values and Leadership Standard ......................................... 3
1.2.1.
Purpose ........................................................................................................................... 3
1.2.2.
Ambition ......................................................................................................................... 3
1.2.3.
Core Values..................................................................................................................... 3
1.2.4.
Leadership Standards ..................................................................................................... 3
1.3.
Organisation Structure – Utilities and Facilities Department .............................................. 4
1.4.
Duties and Responsibilities of Key Personnel ....................................................................... 4
1.4.1.
Site Manager................................................................................................................... 4
1.4.2.
Quality Manager............................................................................................................. 4
1.4.3.
Health and Safety Manager ........................................................................................... 5
1.4.4.
Asset Care Manager ....................................................................................................... 5
1.4.5.
Reliability Lead ............................................................................................................... 5
1.4.6.
Team Leader ................................................................................................................... 5
1.4.7.
Engineer.......................................................................................................................... 5
1.4.8.
Technicians..................................................................................................................... 6
1.4.9.
Operators ........................................................................................................................ 6
1.4.10.
Process Minders ............................................................................................................. 6
CHAPTER TWO: UTILITIES DEPARTMENT .............................................................................. 7
2.1.
Functions of the Utilities Department ................................................................................... 7
2.1.1.
Energy Management ...................................................................................................... 7
2.1.2.
Water Management ........................................................................................................ 7
2.1.3.
Waste Management ........................................................................................................ 7
2.1.4.
Maintenance and Infrastructure ................................................................................... 7
2.1.5.
Safety and Compliance ................................................................................................... 8
2.1.6.
Continuous Improvement and Innovation .................................................................... 8
2.2.
Utilities Plants ........................................................................................................................ 8
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2.2.1.
Air Plant.......................................................................................................................... 8
2.2.2.
Fridge Plant .................................................................................................................. 10
2.2.3.
CO2 Plant ...................................................................................................................... 12
2.2.4.
Effluent Treatment Plant ............................................................................................. 14
2.2.5.
Water Treatment Plant ................................................................................................. 16
CHAPTER THREE: ASSET CARE ................................................................................................. 18
3.1.
Autonomous Maintenance ................................................................................................... 18
3.2.
Preventive maintenance ....................................................................................................... 19
3.3.
Proactive Maintenance......................................................................................................... 19
3.4.
Predictive Maintenance ........................................................................................................ 19
3.5.
Reliability-Centered Maintenance (RCM)........................................................................... 20
3.6.
Continuous Improvement..................................................................................................... 20
CHAPTER FOUR: ELECTRICAL AND INSTRUMENTS .......................................................... 21
4.1.
Pneumatic Cylinders ............................................................................................................ 21
4.2.
Solenoid Valve ...................................................................................................................... 21
4.3.
Coriolis Flow Meter.............................................................................................................. 23
4.4.
Motor Starting Methods ....................................................................................................... 24
4.4.1.
Direct Online (DOL) .................................................................................................... 24
4.4.2.
Star-Delta Starting ....................................................................................................... 25
4.4.3.
Auto-Transformer Starting .......................................................................................... 26
4.4.4.
Soft Starter .................................................................................................................... 27
4.4.5.
Variable Frequency Drive (VFD) ................................................................................ 28
4.5.
Sensors and Actuators .......................................................................................................... 29
4.5.1.
Level sensors ................................................................................................................. 30
4.5.2.
Actuators ....................................................................................................................... 32
4.6.
Solenoids ............................................................................................................................... 34
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CHAPTER ONE: INTRODUCTION
1.1.
Brief History of East African Breweries Limited (EABL)
East African Breweries Limited was founded in 1922, as Kenya Breweries Limited (KBL), by two
white settlers, George and Charles Hurst. KBL initially focused on producing and distributing beer
to meet the demands of the growing expatriate community in the region. In 1923, just a year after
its inception, KBL introduced its flagship brand, Tusker Beer. The name "Tusker" was inspired by
the elephants, which are an iconic symbol of Kenya's wildlife. Tusker quickly gained popularity
among both the expatriate and local communities, becoming a symbol of national pride.
In 1936, KBL merged with Tanganyika Breweries Limited (TBL) and Uganda Breweries Limited
(UBL) to form the East African Breweries Limited (EABL). This merger aimed to consolidate the
brewing industry across the East African region and expand the market reach of their products.
East African Breweries Limited (EABL) has played a significant role in the brewing industry in
East Africa, particularly in Kenya.
Under the umbrella of EABL, the Tusker plant in Nairobi witnessed significant growth and
expansion. The brewery invested in modern equipment, improved production processes, and
introduced new products to cater to the evolving consumer preferences.
In 1986, EABL acquired UDV (United Distillers Vintners), which was the leading spirits producer
in the region. This acquisition allowed EABL to diversify its product portfolio and strengthen its
position as a prominent alcoholic beverage company in East Africa. To date the two key
components of EABL's operations in Kenya include: the Kenya Breweries Tusker Plant and UDV
(United Distillers Vintners).
EABL continued to expand its footprint beyond East Africa. In the late 1990s and early 2000s, the
company ventured into new markets, including South Sudan, Rwanda, and Tanzania. This
expansion strategy aimed to tap into the growing demand for their products in neighboring
countries.
In 2000, EABL entered into a strategic partnership with Diageo, a global leader in the alcoholic
beverages industry. Diageo acquired a majority stake in EABL, providing the company with access
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to Diageo's expertise, resources, and global distribution network. This partnership further
accelerated EABL's growth and positioned it as a major player in the African brewing industry.
EABL has been committed to sustainable practices and corporate social responsibility. The
company has implemented initiatives to promote responsible drinking, reduce their environmental
impact, support local communities, and empower farmers through sustainable agricultural
practices.
Throughout its history, EABL has focused on innovation and introducing new products to meet
changing consumer demands. They have expanded their product range to include a variety of beers,
spirits, and non-alcoholic beverages, catering to different consumer preferences and market
segments.
Today, EABL is one of the leading brewing and distilling companies in East Africa. The Tusker
plant remains a significant production facility within the EABL portfolio, ensuring the continued
popularity and availability of Tusker Beer both domestically and internationally.
The Kenya Breweries Tusker Plant and UDV have been integral to the success of East African
Breweries Limited. The Tusker Plant's establishment, expansion, and sustainability efforts have
solidified EABL's position as a leading brewery in East Africa, with Tusker Lager becoming an
iconic brand. UDV's merger with EABL brought globally recognized spirits brands into the
company's portfolio, enabling diversification and substantial growth in the market. Together, these
entities have contributed to EABL's journey of excellence and innovation in the brewing industry
Some KBL brands include: Tusker, Pilsner, Senator Summit, Allsopps, Balozi etc. and UDV
brands include: Smirnoff, Gilbeys, Chelsea, Three Barrels, Richor, Kenya cane, Kenya Gold,
V&A, Bond 7 and Popov. Other international corporate brand which the company imports and
distributes include: Baileys, Johnnie Walker range, Gordons, J&B Whisky, Pimms, Captain
Morgan and Myers rum.
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1.2.
KBL Purpose, Ambition, Core values and Leadership Standard
1.2.1. Purpose
Celebrating life, everyday, everywhere.
1.2.2. Ambition
To create the best performing, most trusted and respected consumer products company in the
world.
1.2.3. Core Values
They include:
 Passionate about customers & consumers
 Be the best
 Freedom to succeed
 Proud of what we do
 Valuing each other
1.2.4. Leadership Standards
They include:
 Be Authentic
 Create possibilities
 Bring the Diageo purpose to life
 Create the conditions for people to succeed
 Consistently deliver great performance
 Grow yourself
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Organisation Structure – Utilities and Facilities Department
1.3.
Lead Asset Care
Manager
Utilities and
Facilities
Manager
Electrical &
Instrumentation
Engineers
Mechanical
Engineeer
Shift Electrical
Engineer
1.4.
Facilities
Engineer
EISC Lead Asset
Care
Maintenance
Planner
Clerks of Work
IUS Site Manager
IUS Shift Teams
Duties and Responsibilities of Key Personnel
1.4.1. Site Manager
 Project Planning: Site managers participate in project planning and ensure that project
goals, timelines, and objectives are clearly defined.
 Site Supervision: Site managers are responsible for supervising and coordinating site
activities.
 Resource Management: Site managers manage and allocate resources such as manpower,
equipment, and materials to ensure efficient project execution.
1.4.2. Quality Manager
 Oversee quality control processes to ensure that different brands meet the required
standards and specifications. They conduct inspections, perform quality checks, and
address any deficiencies or non-compliance issues promptly.
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1.4.3. Health and Safety Manager
 Ensure that safety procedures and regulations are followed on-site, conduct regular safety
inspections, and address any potential hazards or risks. They may also facilitate safety
training for workers and enforce safety standards.
1.4.4. Asset Care Manager
 Ensures that all assets are functioning optimally, efficiently, and are well-maintained to
minimize downtime, extend their lifespan, and maximize return on investment.
1.4.5. Reliability Lead
 Ensures that products or systems are designed, manufactured, and operated in a reliable
and consistent manner.
 Root Cause Analysis: When failures occur, the reliability lead investigates the root causes
to determine why the failure happened and develop corrective actions.
1.4.6. Team Leader
 Delegating Tasks: Assign tasks to team members based on their skills, expertise, and
capacity.
 Supervision: supervises the team members as they execute the assigned tasks.
1.4.7. Engineer
 Designing and developing of new systems and processes.
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 Troubleshooting technical issues and solving problems that arise in the industry.
 Engineers may also take on project management roles.
1.4.8. Technicians
 Are responsible for installing and maintaining various types of equipment used in the
industry.
 When equipment malfunctions or breaks down, technicians are responsible for diagnosing
the problem, identifying the root cause, and performing repairs.
1.4.9. Operators
 Operators are responsible for operating and controlling machinery, equipment, or systems
used in the industry.
 They conduct routine maintenance checks on the equipment they operate. This can include
inspecting for any signs of damage or wear, lubricating moving parts, and performing
minor repairs or adjustments.
1.4.10. Process Minders
 They help in ensuring the smooth operation of production processes e.g. by cleaning the
machines on daily basis, helping out the operators and also caring out the activities that
cannot be done by the machine e.g. placing the fittings in the cases.
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CHAPTER TWO: UTILITIES DEPARTMENT
The Utilities Department of Kenya Breweries Limited (KBL) is a vital division responsible for
managing and providing essential services to support the brewing operations. This department
plays a crucial role in ensuring the availability of utilities required for the production process and
maintaining efficient and sustainable infrastructure.
2.1.
Functions of the Utilities Department
The functions of The Utilities Department at KBL include:
2.1.1. Energy Management
The Utilities Department handles the management of energy resources, including electricity,
steam, and other forms of energy used in the brewing process. It ensures a reliable and
uninterrupted power supply to support the brewery's operations. Energy conservation measures are
implemented, such as efficient equipment, lighting, and control systems, to minimize energy
consumption and reduce environmental impact. The department explores renewable energy
sources, such as solar power and biogas, to promote sustainability and reduce reliance on nonrenewable resources.
2.1.2. Water Management
The Utilities Department oversees the water supply and management systems within the brewery.
It ensures an uninterrupted and reliable water supply for brewing processes, cooling, cleaning, and
other operational needs. Water treatment and purification processes are implemented to maintain
high-quality standards and minimize environmental impact. The department focuses on water
conservation initiatives to reduce usage, optimize efficiency, and promote sustainability.
2.1.3. Waste Management
Effective waste management is a significant focus for the Utilities Department at KBL. It
implements waste reduction strategies and recycling programs to minimize the environmental
footprint of the brewery's operations. The department ensures proper disposal of waste materials,
adhering to regulatory guidelines and promoting environmentally responsible practices. Effluent
treatment processes are implemented to treat and manage wastewater, ensuring compliance with
environmental regulations and protecting water resources.
2.1.4. Maintenance and Infrastructure
The Utilities Department is responsible for the maintenance and upkeep of utility infrastructure
within the brewery. It conducts regular inspections, preventive maintenance, and repairs of
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equipment and systems to ensure optimal functionality and minimize downtime. The department
oversees the installation of new utility systems and upgrades existing infrastructure to improve
efficiency and capacity. It collaborates with other departments to identify areas for improvement,
implement energy-saving measures, and optimize utility usage.
2.1.5. Safety and Compliance
The Utilities Department ensures compliance with safety regulations and industry standards for
utility operations. It conducts risk assessments, implements safety protocols, and provides training
to employees to mitigate risks associated with utility systems. The department maintains records,
conducts audits, and collaborates with relevant authorities to ensure compliance with
environmental and regulatory requirements.
2.1.6. Continuous Improvement and Innovation
The Utilities Department at KBL strives for continuous improvement and innovation in utility
management. It explores new technologies, processes, and practices to enhance operational
efficiency, reduce costs, and minimize environmental impact. The department actively participates
in research and development initiatives to identify sustainable and energy-efficient solutions for
utility management.
2.2. Utilities Plants
Based on the functions discussed above the utilities department consists of several plants. They
include: Effluent Treatment Plant, Water Recovery Plant, Air Plant, CO2 Plant, Fridge Plant, Water
Plant, Steam Plant and Electrical Plant.
2.2.1. Air Plant
The Air Plant at Kenya Breweries Limited (KBL) is a critical component of the brewery's
operations, responsible for providing compressed air for various processes and equipment
throughout the facility.
The air plant at KBL produces air at a pressure of 7bars which is then transferred to different
departments e.g. brewing, packaging and UDV. The compressed air is used in different electrical
components such as pneumatic cylinders, pneumatic valves, pneumatic pumps etc.
The air plant comprises of two types of compressors i.e. Fixed compressors that run at a constant
speed and Variable compressors whose speed is varied by use of a variable speed drive. At any
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given time, there is always two compressors running one which is fixed and the other variable and
an additional standby compressor. An optimizer is used to monitor the compressors in operation.
This key aspects and functions of the Air Plant at KBL:
1. Compressed Air Generation: The Air Plant is responsible for generating compressed air,
which is an essential utility in the brewing process. It utilizes air compressors to compress
atmospheric air, increasing its pressure and storing it in receivers for distribution. Compressed
air is used in various applications, including pneumatic control systems, bottle and can filling,
packaging equipment, and cleaning processes.
2. Distribution and Pipework: The Air Plant distributes compressed air through a network of
pipework throughout the brewery. The pipework system delivers compressed air to the areas
and equipment where it is required, ensuring efficient and reliable supply. Proper sizing,
layout, and maintenance of the pipework are crucial to minimize pressure drops, leaks, and
energy losses.
3. Air Quality and Treatment: The Air Plant ensures that the compressed air supplied to the
brewery meets specific quality standards. It includes filtration systems to remove
contaminants, such as dust, oil, and moisture, from the compressed air. Proper air treatment
helps maintain the integrity of products, equipment efficiency, and the overall quality of the
brewing process.
4. Energy Efficiency and Optimization: The Air Plant focuses on energy efficiency and
optimization to minimize energy consumption and operational costs. It employs advanced
control systems and monitoring tools to optimize compressor operation, reducing energy
wastage during periods of low demand. Regular maintenance and audits are conducted to
identify opportunities for energy-saving measures and system improvements.
5. Maintenance and Safety: The Air Plant requires regular maintenance and inspections to ensure
its reliable operation and safety. Maintenance activities include routine checks, lubrication,
cleaning, and monitoring of equipment performance. Safety protocols are in place to safeguard
personnel working in proximity to air compressors and associated equipment.
6. Environmental Impact and Sustainability: The Air Plant at KBL strives to minimize its
environmental impact and promote sustainability. Efforts are made to reduce air leaks,
optimize compressor operation, and implement energy-saving measures to reduce carbon
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footprint. The Air Plant collaborates with other departments to explore innovative solutions,
such as energy recovery systems, to further enhance sustainability.
Fig. 2.1: Air Plant Flow Chart
2.2.2. Fridge Plant
The Fridge Plant at Kenya Breweries Limited (KBL) is a crucial component of the company's
operations, responsible for the production and maintenance of refrigeration systems used to store
and chill beverages.
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The fridge plant consists of key components that play vital roles in the refrigeration process,
utilizing ammonia as the refrigerant and industrial methylated spirit (IMS) as the coolant.
The key aspects and functions of the Fridge Plant at KBL with reference to the provided
information:
1. Compressor: The compressor is a crucial component of the Fridge Plant that compresses the
gaseous ammonia refrigerant. By compressing the refrigerant, the compressor increases its
pressure and temperature, preparing it for the subsequent cooling process.
2. Condenser: The condenser in the Fridge Plant is responsible for removing heat from the
compressed ammonia refrigerant. It facilitates the conversion of the gaseous ammonia into a
liquid state by cooling it using water. Through this cooling process, the condenser helps in the
removal of heat energy from the refrigerant.
3. PHE (Plate Heat Exchanger): The Plate Heat Exchanger (PHE) also known as an evaporator
is a key component where the heat exchange between the liquid ammonia refrigerant and the
industrial methylated spirit coolant occurs. The PHE facilitates the transfer of heat from the
coolant (IMS) to the refrigerant (ammonia) through the process of heat exchange. This heat
transfer helps in cooling the IMS, which is then used in the brewing department for the cooling
of beer.
4. Expansion Valve: The expansion valve controls the flow of the refrigerant (liquid ammonia)
into the Plate Heat Exchanger (PHE). By regulating the flow, the expansion valve ensures the
proper distribution and amount of refrigerant entering the PHE for efficient heat exchange.
The refrigeration process in the Fridge Plant follows the described sequence:
 Gaseous ammonia refrigerant is compressed by the compressor, increasing its pressure and
temperature.
 The compressed ammonia then enters the condenser, where it is cooled using water, resulting
in the conversion of the refrigerant from a gas to a liquid state.
 The liquid ammonia refrigerant is transferred to the Plate Heat Exchanger (PHE) where heat
exchange occurs between the liquid ammonia and the industrial methylated spirit coolant.
 The industrial methylated spirit, which has been cooled by the heat exchange, is then
transferred to the brewing department for use in the cooling of beer.
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 Meanwhile, the gaseous ammonia refrigerant is returned to the compressor to restart the
cycle, and the process continues.
It is worth noting that the industrial methylated spirit (IMS) from the brewing department typically
enters the Fridge Plant at a temperature of T=0.7 degrees Celsius. Through the refrigeration
process, the IMS is further cooled to a temperature of T=-2.6 degrees Celsius before it is utilized
in the beer cooling process.
Fig 2.2: Industrial Refrigeration Process
2.2.3. CO2 Plant
The CO2 Plant at Kenya Breweries Limited (KBL) plays a crucial role in producing and supplying
carbon dioxide (CO2) gas for various applications in brewing and distilling processes.
The key aspects and functions of the CO2 Plant at KBL include:
1. Production of CO2: The CO2 Plant produces carbon dioxide gas, which is essential for
beverage production. During the fermentation process, yeast converts sugars in the wort into
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alcohol and CO2 gas. The CO2 Plant captures and collects the CO2 gas produced by yeast
during fermentation, ensuring its availability for subsequent use.
2. CTs (Conical Tanks): The conical tanks, also known as CTs, are utilized in the brewing for
the fermentation process. These tanks provide a controlled environment for yeast to convert
sugars into alcohol and CO2. The CTs facilitate the efficient production and collection of CO2
gas during the fermentation process.
3. Reboiler: The reboiler is a key component of the CO2 Plant that cools the gaseous CO2 into a
liquid state. It utilizes ammonia as the refrigerant to lower the temperature of the CO 2 gas,
causing it to condense into a liquid form. This cooling process allows for the efficient
conversion of gaseous CO2 into liquid CO2, which can be stored and utilized as needed.
4. Liquivap: The Liquivap is a component that separates the CO2 gas and liquid CO2 produced
in the plant. It ensures that the liquid CO2 is properly separated and sent for storage, while the
CO2 gas can be directly supplied to users.
5. Storage and Distribution: The CO2 Plant at KBL includes storage facilities for the liquid CO2
produced. The liquid CO2 is stored until it is needed for various applications. When required,
the liquid CO2 can be sent to a vaporizer, where it is converted back into gas form before being
transferred to the users.
6. Application in Brewing and Distilling: CO2 produced in the plant is used in brewing and
distilling processes to remove air and protect the product from oxidation. It ensures the
preservation of taste, mouthfeel, quality, and shelf stability of the beverages. The CO2 gas is
also responsible for creating the characteristic "fizz" or carbonation in beer, enhancing its
sensory experience.
Fig. 2.3: CO2 Recovery Plant
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2.2.4. Effluent Treatment Plant
The Effluent Treatment Plant at Kenya Breweries Limited (KBL) plays a vital role in treating and
managing the wastewater generated during the brewing process. With a focus on sustainability and
environmental responsibility, the plant utilizes anaerobic digesters for effluent treatment.
The Effluent Treatment Plant at Kenya Breweries Limited follows a process flow that involves
multiple stages to effectively treat the wastewater generated during the brewing process. The
typical process flow in the Effluent Treatment Plant is as follows:
 Collection and Screening: Wastewater from various stages of the brewing process is collected
and directed to the Effluent Treatment Plant. The wastewater may first undergo a preliminary
screening process to remove larger solid particles, such as debris or packaging materials, to
protect downstream equipment and facilitate subsequent treatment processes.
 Equalization: In the equalization tank, the collected wastewater is mixed and homogenized.
This stage helps to equalize the flow and composition of the wastewater, ensuring consistent
treatment conditions and facilitating more efficient subsequent treatment processes.
 Anaerobic Digestion: The equalized wastewater is then directed to anaerobic digesters, which
are specialized tanks designed to create an oxygen-free environment. Within the anaerobic
digesters, specific groups of microorganisms, known as anaerobic bacteria, break down
organic matter in the absence of oxygen. The microorganisms feed on the organic pollutants
in the wastewater, converting them into biogas (primarily methane and carbon dioxide) and
producing a treated effluent.
 Biogas Recovery: As the anaerobic digestion process takes place, biogas is produced. The
Effluent Treatment Plant collects and captures the biogas generated during anaerobic
digestion. The biogas is then utilized as a renewable energy source within the brewery,
contributing to the facility's energy needs and reducing reliance on conventional fossil fuels.
 Treated Effluent Separation: After the anaerobic digestion process, the treated effluent is
separated from the remaining sludge. The separation process may involve settling tanks or
other separation techniques to separate the treated effluent from the solid residues.
 Sludge Management: The sludge, which is a byproduct of the anaerobic digestion process,
undergoes further treatment or processing. This may include dewatering processes to reduce
the moisture content of the sludge or additional treatment to improve its environmental
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characteristics. Depending on the nature of the sludge, it may be disposed of in an
environmentally responsible manner or undergo further beneficial use or recycling.
 Final Effluent Discharge or Reuse: Some of the treated effluent, free from organic pollutants
and with reduced levels of contaminants, is typically discharged in compliance with
environmental regulations. Most of the treated effluent undergoes additional treatment at the
water recovery plant after which it is to be subjected to further reuse within the brewery, such
as for cleaning.
The key aspects and functions of the Effluent Treatment Plant at KBL:
1. Wastewater Treatment: The Effluent Treatment Plant is responsible for treating the
wastewater generated from various stages of the brewing process. It employs anaerobic
digesters, which are specialized tanks where microorganisms break down organic matter in
the absence of oxygen. The anaerobic digestion process helps to remove organic pollutants
and reduce the overall biological oxygen demand (BOD) and chemical oxygen demand (COD)
of the wastewater.
2. Anaerobic Digesters: Anaerobic digesters are the key components of the Effluent Treatment
Plant at KBL. They provide an oxygen-free environment for the growth and activity of specific
microorganisms that aid in the decomposition of organic materials. The microorganisms break
down the organic pollutants present in the wastewater, converting them into biogas and
producing a treated effluent.
3. Biogas Production: During the anaerobic digestion process, the organic matter in the
wastewater is converted into biogas. Biogas typically contains methane and carbon dioxide,
which can be captured and utilized as a source of renewable energy. The Effluent Treatment
Plant at KBL collects and harnesses the biogas produced for various energy needs within the
brewery, reducing reliance on fossil fuels.
4. Compliance and Environmental Impact: The Effluent Treatment Plant ensures compliance
with environmental regulations and standards for wastewater discharge. It regularly monitors
and tests the treated effluent to ensure it meets the specified quality requirements. By
effectively treating the wastewater, the plant minimizes the impact on receiving water bodies,
protects the environment, and contributes to sustainable water resource management.
5. Continuous Improvement and Sustainability: The Effluent Treatment Plant at KBL is
committed to continuous improvement and sustainability in wastewater management. It
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explores innovative technologies and practices to optimize the treatment process, enhance
efficiency, and reduce resource consumption. The plant actively promotes water conservation,
pollution prevention, and the reuse or recycling of treated wastewater to minimize the
brewery's overall water footprint.
2.2.5. Water Treatment Plant
The Water Recovery Plant at Kenya Breweries Limited (KBL) plays a crucial role in further
treating the treated effluent from the Effluent Treatment Plant to produce high-quality water for
various purposes within the brewery.
Process Flow of the Water Recovery Plant includes:
 Filtration: The treated effluent undergoes an initial filtration process to remove any remaining
suspended solids and particulate matter. This step helps to improve the clarity and cleanliness
of the water for subsequent treatment stages.
 Advanced Treatment: The filtered effluent then undergoes advanced treatment processes,
which may include methods such as membrane filtration, reverse osmosis, and activated
carbon filtration. These processes are designed to further remove dissolved impurities,
including salts, organic compounds, and trace contaminants, ensuring the production of highquality reclaimed water.
 Disinfection: After the advanced treatment stages, the water is subjected to a disinfection
process to eliminate any remaining microorganisms and pathogens. Common disinfection
methods include chlorination, ultraviolet (UV) disinfection, or ozonation, which effectively
kill or inactivate harmful microorganisms.
 Storage and Distribution: The reclaimed water is stored in dedicated storage tanks, which are
separate from freshwater sources, to prevent cross-contamination. Depending on the specific
reuse applications, the reclaimed water is then distributed through a separate distribution
system to various areas within the brewery where non-potable water is required.
 Monitoring and Quality Control: Continuous monitoring and regular testing are conducted to
ensure that the reclaimed water meets the required quality standards. Parameters such as pH,
turbidity, disinfection levels, and microbial content are regularly monitored to maintain water
quality and compliance with regulations.
Some key Aspects and Functions of the Water Recovery Plant include:
16
1. Additional Treatment: The Water Recovery Plant receives the treated effluent from the
Effluent Treatment Plant for further treatment and purification. The goal is to remove any
remaining impurities and contaminants to ensure the production of high-quality water.
2. Water Reuse: The primary function of the Water Recovery Plant is to produce reclaimed water
that can be reused within the brewery for non-potable purposes. Reclaimed water may be
utilized for activities such as equipment cleaning, cooling systems, and irrigation, depending
on its quality and suitability.
3. Sustainability and Resource Conservation: The Water Recovery Plant aligns with KBL's
commitment to sustainability and resource conservation. By treating and reusing the treated
effluent, the plant reduces the demand for freshwater sources, conserving water resources and
minimizing the brewery's environmental footprint.
4. Compliance and Quality Control: The Water Recovery Plant ensures compliance with
regulatory standards for water quality. Stringent quality control measures and testing protocols
are implemented to ensure that the reclaimed water meets the required specifications for its
intended reuse purposes.
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CHAPTER THREE: ASSET CARE
Asset Care refers to the systems and activities which are needed to ensure maximum equipment
availability and performance at an optimum cost.
Asset Care is a comprehensive approach applied in Kenya Breweries Limited (KBL) to ensure the
efficient and effective management of its assets i.e. machines throughout their lifecycle. Asset
Care involves autonomous maintenance, preventive maintenance and continuous improvement
practices to maximize asset performance, reliability, and longevity.
Some types of maintenances include
 Preventive Maintenance: includes regular and periodic (time-based) schedules.
 Corrective Maintenance: done when an issue is noticed.
 Predetermined Maintenance: follows a factory schedule.
 Condition Based Maintenance: done when a situation or condition indicates maintenance
is needed.
 Predictive Maintenance: it is data given and impacted by present parameters.
 Reactive Maintenance: done when a total breakdown or failure appears.
3.1.
Autonomous Maintenance
It is an approach to equipment maintenance that involves:
 Cleaning- which includes dusting the electrical panels and cleaning the machines using dry
or wet clothes.
 Inspection- which is a careful examination of the machines to check for any abnormality.
 Lubrication-which is the application of oil or grease to the moving parts of a machine so
as to minimize friction and allow smooth movement.
 Tightening-all the identified loose parts are tightened.
During autonomous maintenance all the errors that can be corrected immediately without having
to shut down the lines are corrected while those that can’t be collected immediately are scheduled
to be done at a later date. This type of maintenance helps maximize equipment effectiveness and
improve overall productivity.
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Benefits of Autonomous Maintenance include
 Ensuring the equipment is properly cleaned and lubricated.
 Identifying issues before they lead to critical equipment failure.
 Freeing maintenance personnel for more complex maintenance tasks.
 Improving overall safety.
3.2.
Preventive maintenance
It is a type of maintenance that aims to predict and prevent equipment failures before they occur.
In KBL it is achieved by:
 Scheduling and performing regular inspections of the machines and other equipment.
 Conducting regular cleaning of the machines.
 Lubricating moving parts to avoid wear and tear and where vibrations are more likely to
occur a thread locker is used to seal and secure the nuts and bolts.
 Repairing and replacing any defective equipment parts.
3.3.
Proactive Maintenance
Asset Care emphasizes proactive maintenance practices to prevent equipment failures and
minimize unplanned downtime.
It involves conducting regular inspections, lubrication, and calibration of assets to ensure optimal
performance and reliability.
Proactive maintenance includes preventive maintenance tasks, such as routine servicing,
component replacements, and system checks based on established maintenance schedules.
3.4.
Predictive Maintenance
KBL utilizes predictive maintenance techniques to monitor asset conditions and detect early signs
of potential failures.
Predictive maintenance involves employing various technologies, such as vibration analysis,
thermography, and oil analysis, to assess asset health and performance.
By analyzing data and trends, maintenance activities can be planned in advance to address potential
issues before they result in major failures or breakdowns.
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3.5.
Reliability-Centered Maintenance (RCM)
RCM is a key aspect of Asset Care in KBL, focusing on optimizing asset reliability and
performance.
It involves identifying critical assets, determining failure modes and their consequences, and
developing maintenance strategies accordingly.
RCM helps prioritize maintenance efforts, ensuring that resources are allocated to the most critical
assets to minimize risks and maintain operational reliability.
3.6.
Continuous Improvement
Asset Care at KBL emphasizes continuous improvement practices to optimize asset performance
and reduce life cycle costs.
It involves analyzing maintenance data, performance metrics, and feedback to identify
opportunities for improvement.
Continuous
improvement
initiatives
may
include
implementing
reliability-enhancing
modifications, upgrading equipment, and adopting new technologies to enhance asset
performance, efficiency, and safety.
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CHAPTER FOUR: ELECTRICAL AND INSTRUMENTS
Electrical instruments play a crucial role in Kenya Breweries Limited (KBL) by facilitating various
electrical measurements, controls, and monitoring processes. These instruments are utilized to
ensure the safe and efficient operation of electrical systems and equipment within the brewery.
Some common electrical instruments used in KBL include:
4.1.
Pneumatic Cylinders
Pneumatic cylinders are mechanical devices that produce force by using energy from pressurized
air. These devices consist of a piston, piston rod, and cylinder. The pressure inside the cylinder
rises as air enters on one side of the cylinder. The rise in internal pressure causes the piston to
move in a specific direction. The piston rod transmits the developed force to the object to be
moved.
Fig. 4.1: Pneumatic Cylinder
The working fluid in pneumatic cylinders is compressed air. Hence, pneumatic cylinders are
desirable for environments requiring a high level of cleanliness, as the fluid will not contaminate
the surroundings in case of leakage. They are used in the automation of machines and industrial
processes. The force and motion produced by pneumatic cylinders can be used in mechanisms
such as clamping, ejecting, blocking, and lifting. In factories, they are used in repetitive pick-up
and placement of objects into a machine or equipment. In piping systems, they are used in
operating valves.
4.2.
Solenoid Valve
It is a special type of valve used in pneumatic systems. Its main supply is the compressed air from
the compressor. The compressed air is then directed into two different directions to open and close
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the slide gate valve of the pneumatic cylinder. The solenoid valve has an electrical coil that is
energized by a 24V command from the PLC card.
Fig. 4.2: Solenoid Valve
Fig. 4.3b: Solenoid valve when the PLC
Fig. 4.3a: Solenoid valve when the
PLC exerts the command
removes the command
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4.3.
Coriolis Flow Meter
The flow meter has two parallel flow tubes. When the process fluid enters the sensor, it spreads
and half of the fluid passes through each fluid. During operation a drive coil stimulates the tubes
to oscillate in opposition to each other at the natural resonant frequency of the tubes. Magnetic
coils assemblies which are called pickups are mounted on the flow tubes and as the tubes oscillates
the voltage generated from each pickoff creates a sine wave i.e. inlet pickoff and outlet pickoff.
The sine waves generated indicates the motion of one tube relative to the other.
When there is no flow the inlet and outlet sine waves are in phase meaning they are in a
synchronized motion. When fluid is moving through the sensor tubes Coriolis forces are induced
in both flow tubes and these forces cause the flow tubes to twist in opposition to each other
resulting to the sine waves being shifted in phase with respect to each other and are asynchronous.
The time delay between the two sine waves is measured in microseconds Delta t which is directly
proportional to the flow rate. Thus, the greater the phase shift the greater the flow rate. While the
sine wave phase shift indicates the flow rate, the wave frequency indicates the density. When liquid
density changes the vibrating frequency of the tubes also changes.
Fig. 4.4: Coriolis Flow Meter
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4.4.
Motor Starting Methods
Motor starting methods refer to the techniques used to initiate the operation of electric motors. The
starting method employed depends on factors such as the motor type, power rating, and application
requirements.
4.4.1. Direct Online (DOL)
Direct On-Line is the simplest and cheapest method used for starting three-phase motor. DOL is
used for up to 5 HP motor. DOL starter connects the motor directly to supply without a reduction
in supply voltage and applies full line voltage to 3 phase motor. (Its main disadvantage)
DOL starting is the simplest and most common method used for small to medium-sized motors.
With this method, the motor is directly connected to the power supply, typically through a
contactor. When the motor is energized, it starts at full voltage, resulting in high starting current
and mechanical stress. DOL starting is suitable for applications where the load inertia is low, and
the starting torque requirement is not excessive.
DOL starter of three phase induction motors control and power circuit consists MCB or fuse unit
which connected in series with the supply. Power contactor, thermal overload relay for protection
and stop and start push button.
Fig. 4.5: DOL Starter Wiring Diagram
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A DOL (Direct-On-Line) starter is an electrical device used to start and stop motors. It consists of
a magnetic contactor and an overload relay. The magnetic contactor is an electromechanical switch
that is used to connect the motor to the power supply.
The working principle of a DOL starter using a magnetic contactor is as follows:
 Start Button Pressed: The operator presses the start button to initiate the motor start-up
sequence.
 Contactor Coil Energized: The start signal energizes the contactor coil, creating a magnetic
field that pulls the contactor armature towards the fixed contacts.
 Main Contacts Close: As the armature moves towards the fixed contacts, the main contacts of
the contactor close, connecting the motor to the power supply.
 Motor Runs: The motor starts to run and draws current from the power supply.
 Overload Relay Monitors Current: An overload relay is connected in series with the motor,
and it monitors the current drawn by the motor. If the current exceeds a predetermined level,
the overload relay will trip and stop the motor to prevent damage due to overheating.
 Stop Button Pressed: To stop the motor, the operator presses the stop button, which interrupts
the power supply to the contactor coil, causing the contactor armature to return to its resting
position, and the main contacts to open, disconnecting the motor from the power supply.
In summary, a DOL starter using a magnetic contactor provides a simple and reliable way to start
and stop motors, by using an electromechanical switch to connect and disconnect the motor from
the power supply, and an overload relay to protect the motor from damage due to excessive current
draw.
4.4.2. Star-Delta Starting
Star-delta starting, also known as Wye-Delta starting, is used for larger motors with moderate
starting torque requirements. The motor windings are initially connected in a star configuration
(lower voltage) for starting. Once the motor reaches a certain speed, typically around 80% of its
rated speed, the windings are switched to a delta configuration (higher voltage) for normal
operation. Star-delta starting reduces the starting current and torque, minimizing mechanical stress
during the start-up phase.
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Fig. 4.6: Star Delta Starter Wiring Diagram
Working Principle:
 In star-delta starting, the motor windings are initially connected in a star configuration during
the starting phase.
 The motor receives a reduced voltage, typically around 30% to 50% of the full voltage,
resulting in a reduced starting current and torque.
 After the motor reaches a predetermined speed (around 80% of its rated speed), the windings
are switched to a delta configuration for normal operation, receiving the full supply voltage.
 Star-delta starting reduces the mechanical stress during starting and minimizes the impact
on the power supply, but it provides lower starting torque compared to DOL starting.
4.4.3. Auto-Transformer Starting
Auto-transformer starting is another method employed for reducing the starting current and torque
in medium-sized motors. An auto-transformer is used to temporarily reduce the voltage applied to
the motor during starting. The motor windings are initially connected to taps on the autotransformer, providing a lower voltage at start-up. Once the motor gains sufficient speed, it is
switched to the full supply voltage for normal operation.
26
Fig. 4.7: Auto-Transformer Starter Wiring Diagram
Working Principle:
 Auto-transformer starting utilizes an auto-transformer to temporarily reduce the voltage
supplied to the motor during the starting period.
 The motor windings are initially connected to taps on the auto-transformer, which provides
a reduced voltage to limit the starting current and torque.
 Once the motor reaches a specific speed, it is switched to the full supply voltage, providing
the necessary torque for normal operation.
 Auto-transformer starting reduces the mechanical stress on the motor and connected
equipment while allowing for a smooth and controlled start.
4.4.4. Soft Starter
Soft starters are electronic devices designed to gradually start and control the voltage applied to
the motor. They provide a smooth and controlled acceleration, reducing the starting current and
torque. Soft starters employ solid-state electronics to regulate the voltage, enabling a gradual
increase in motor speed. Soft starters are particularly useful for applications where high starting
torque or limited inrush current is required, such as conveyors and pumps.
27
Fig. 4.8: Soft Starter Wiring Diagram
Working Principle:
 Soft starters control the voltage supplied to the motor by using solid-state electronics.
 They employ semiconductor devices, such as thyristors or power transistors, to gradually
increase the voltage during motor start-up.
 The soft starter gradually increases the voltage and current, providing a smooth acceleration
and reducing the mechanical stress on the motor.
 By controlling the voltage, soft starters enable precise acceleration and deceleration, torque
control, and protection against voltage spikes and motor overloads.
4.4.5. Variable Frequency Drive (VFD)
VFDs, also known as adjustable frequency drives or inverters, offer the most versatile motor
starting method. They control the motor speed and torque by varying the frequency and voltage of
the supplied power. VFDs enable smooth and precise acceleration, deceleration, and speed control,
providing flexibility and energy efficiency. VFDs are commonly used in applications where
precise control over motor speed and torque is required, such as industrial machinery and HVAC
systems.
28
Fig. 4.9: VFD Starter Wiring Diagram
Working Principle:
 VFDs control the motor speed by adjusting the frequency and voltage of the power supplied
to the motor.
 The VFD converts the incoming AC power to DC and then inverts it back to AC with a
variable frequency and voltage.
 By varying the frequency and voltage, the VFD allows for precise control of motor speed
and torque.
 VFDs enable soft starting, smooth acceleration and deceleration, energy-efficient operation,
and features such as speed control, overload protection, and regenerative braking.
4.5.
Sensors and Actuators
Sensors are devices used to monitor different industrial processes, collect data, take measurement,
and send the data to centralized cloud computing platforms where information is collected and
analyzed for patterns. They detect physical, chemical, or biological changes in the environment
29
and convert them into electrical or digital signals that can be analyzed and interpreted by a
computer or other electronic device. The different types of sensors include:
4.5.1. Level sensors
A level sensor is a device that is designed to monitor, maintain, and measure liquid (and sometimes
solid) levels. Once the liquid level is detected, the sensor converts the perceived data into an
electric signal.
Level Sensor are classified based on:
 Point level measurement- which indicates when a product is present at a certain point
 Continuous level measurement -indicates the continuous level of a product as it rises and
falls.
The sensors-based point level indication include:
1. Capacitance Level Sensors: These sensors are used to detect the liquid levels like slurries and
aqueous liquids. They are operated by using a probe for checking level changes. These level
changes are transformed into analog signals. The probes are generally made of conducting
wire by PTFE insulation. But, stainless steel probes are extremely responsive and hence they
are appropriate for measuring non-conductive substance granular or materials with low
dielectric constant. These types of sensors are very simple to use and clean as they do not have
any moving components.
Fig. 4.10: Capacitance Level Sensors
2. Conductivity level sensor: A conductivity or resistance sensor uses a probe to read
conductivity. The probe has a pair of electrodes and applies alternating current to them.
30
When a liquid covers the probe, its electrodes form a part on an electric circuit, causing
current to flow which signals a high or low level.
Fig. 4.11: Conductivity Level Sensors
The sensors based Continuous Level Measurement include:
1. Ultrasonic level sensors: Ultrasonic level sensors are used to detect the levels of sticky
liquid substances and bulkiness materials as well. They are worked by producing audio
waves at the range of frequency from 20 to 200 kHz. These waves are then replicated back
to a transducer. The ultrasonic sensor’s response is influenced by turbulence, pressure,
moisture, and temperature.
Fig. 4.12: Ultrasonic Level Sensors
2. Inductive Sensor: An inductive sensor is a device that uses the principle of electromagnetic
induction to detect or measure objects. An inductor develops a magnetic field when a
31
current flow through it; alternatively, a current will flow through a circuit containing an
inductor when the magnetic field through it changes. This effect is used to detect metallic
objects that interact with a magnetic field.
3. Capacitive Sensor: It is a sensor that can detect solid or liquid targets without physical
contact. To detect these targets, capacitive sensors emit an electrical field from the sensing
end of the sensor and any target that disrupts this electrical field can be detected by the
capacitive sensor. Examples of materials a capacitive sensor can detect are: metal, plastic,
wood, paper, glass and cloth. They also detect liquids like water, oil and paint.
4. Photoelectric Sensor: It is a device used to determine the distance, absence or presence of
an object by using a light transmitter often infrared and a photoelectric receiver. When the
emitted light is interrupted by an object in close proximity, the light receiver detects this
change and turns the output of the sensor on or off.
4.5.2. Actuators
Actuators are devices or components that convert electrical, hydraulic, or pneumatic energy into
mechanical movement or force. They are used to control or automate various types of machines
and systems, such as valves, pumps, motors, and robotics.
Actuators are commonly used in industrial applications, such as manufacturing, transportation, and
energy production, as well as in consumer products like automobiles, home appliances, and
medical devices. Some common types of actuators include electric motors, hydraulic cylinders,
pneumatic pistons, and solenoids.
Actuators can be operated manually, through remote control or automation, and can be used for
various purposes, such as opening and closing valves, moving parts in machines, regulating fluid
flow, and providing linear or rotational motion.
Types of actuators include:
1. Pneumatic (air pressure) actuators: A pneumatic actuator is a type of device that converts
energy from compressed air into mechanical motion. It is commonly used in a wide range
of industrial applications where linear or rotational motion is required, such as in valves,
dampers, and other types of process control equipment. The working principle of a
pneumatic actuator is relatively simple. The device is typically composed of a cylinder, a
piston, and a control valve. Compressed air is supplied to the control valve, which directs
32
the flow of air to either side of the piston, causing it to move back and forth within the
cylinder. It involves:
 When compressed air is supplied to one side of the piston, it pushes the piston in the
opposite direction, causing the actuator to move in one direction. When the air supply
is switched to the other side of the piston, it pushes the piston back in the other
direction, causing the actuator to move in the opposite direction.
 The speed and force of the actuator's movement can be controlled by regulating the
flow of compressed air to the control valve. By adjusting the air pressure and flow rate,
the actuator can be made to move more quickly or slowly, with greater or lesser force.
 Overall, the principle of operation of a pneumatic actuator is based on the use of
compressed air to create mechanical motion, making it a reliable and effective solution
for a wide range of industrial automation applications.
2. Hydraulic (fluid pressure) actuators: A hydraulic actuator is a device that converts
hydraulic pressure into mechanical force and motion. It consists of a cylinder, a piston, a
piston rod, and a hydraulic fluid. The working principle of a hydraulic actuator is based on
Pascal's law, which states that pressure applied to an enclosed fluid is transmitted uniformly
in all directions. It involves:
 When hydraulic fluid is pumped into the cylinder of the actuator, it applies pressure to
the piston, causing it to move. The piston rod attached to the piston also moves along
with it. The direction of the piston movement is determined by the direction of fluid
flow into the cylinder.
 The force generated by the hydraulic pressure is proportional to the surface area of the
piston. Therefore, a larger piston generates more force than a smaller one. The force
generated by the actuator can be controlled by regulating the flow of hydraulic fluid
into the cylinder.
Hydraulic actuators are used in various applications where high force and precise control
are required, such as in heavy machinery, construction equipment, and aerospace systems.
They are preferred over other types of actuators because they are capable of generating
high force with very little effort and can maintain their position without the need for
external power.
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3. Electric actuators: Electric actuators are devices that convert electrical energy into
mechanical motion or force. They are used to control valves, dampers, and other
mechanical systems in various industries such as power generation, oil and gas, water
treatment, and manufacturing. The working principle of electric actuators depends on the
type of actuator, but generally involves the following components:
 Electric motor: Electric actuators are powered by electric motors that convert electrical
energy into rotational mechanical energy. The motor can be either AC or DC
depending on the application.
 Gear train: The rotational motion of the electric motor is transmitted to the output shaft
of the actuator through a gear train. The gear train provides the necessary torque and
speed required for the actuator to perform its function.
 Control circuit: The control circuit is responsible for receiving and interpreting signals
from the control system, and then commanding the electric motor to rotate in a specific
direction and at a specific speed.
 Feedback sensor: The feedback sensor provides information about the position and
speed of the output shaft to the control circuit. This allows the control circuit to ensure
that the actuator is in the correct position and moving at the desired speed.
 Output mechanism: The output mechanism of the actuator is the component that
interfaces with the mechanical system being controlled, such as a valve or damper. The
output mechanism converts the rotational motion of the output shaft into linear motion
or torque to operate the mechanical system.
Overall, the working principle of electric actuators involves converting electrical energy
into mechanical motion through the use of an electric motor, gear train, control circuit,
feedback sensor, and output mechanism. This allows for precise and efficient control of
mechanical systems in various industries.
4.6.
Solenoids
A solenoid is an electromagnetic device that converts electrical energy into linear motion. It
consists of a coil of wire wrapped around a ferromagnetic core. When an electrical current flow
through the coil, it creates a magnetic field that causes the core to move along the axis of the coil.
34
The working principle of a solenoid can be explained in four steps:
 When an electrical current is passed through the coil, a magnetic field is generated. The
strength of the magnetic field is proportional to the current passing through the coil.
 The ferromagnetic core inside the coil is attracted towards the center of the coil due to the
magnetic field generated by the coil.
 When the electrical current is turned off, the magnetic field collapses, and the
ferromagnetic core returns to its original position due to a spring or force acting in the
opposite direction.
 By controlling the electrical current passing through the coil, the movement of the core can
be precisely controlled.
Solenoids are used in a variety of applications, such as in door locks, valves, and starter motors.
35