Fluid Machineries
Examples of valves
NOTE: MANUALLY operated (one rotating hand wheel or level)
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Lpg regulator
– pressure regulating valve.
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Angle valve
– it can be seen in bathroom fixture (bidet)
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Globe valve
– faucet is a primary example.
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Pressure regulating valve
– it makes used of a pressure gauge and it has adjustable knob.
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Foot valve
– it can be seen in irrigation system and pumping system.
– we introduce water to the pump itself to establish negative pressure to make the flow of water continuously.
– the reason we introduce water is because of having a damaged on the foot valve which can be seen in the bottom of our pump.
– Foot valve doesn’t have a mechanical feature and was made from weighted piece of rubber.
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Ball valve, diaphragm valve, Swing check valve
– it is used and can be found in industry.
– To distinguish if the valves is being used in industry, we can check its corresponding sizes.

Variety of valves
– made from thermoplastics.
 Thermoplastics
– a type of material which is capable of withstanding high temperature and high pressure.

Motor actuated globe valve
– Automatically operated by means of using electric motor.

Motor actuated or manually operated globe valve
– It can be operated in two possible ways: Automatically by using electric motor or by overriding it manually.

Pneumatically actuated ball valve, pneumatically actuated butterfly valve, pneumatically actuated glove valve
– It is automatically operated by means of using compress lines or compress airs (pressure from air)

Supersized gate valve, supersized swing check valve, supersized ball valve
– It is only can be seen in industry because of its sheer size.
– it is operated by means of an electric motor or mechanical mechanism to introduce mechanical flexibility or mechanical
advantage (magnifying work imparted on the rotating wheels)
Valves
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devices that control flow of the fluids in between the interfaces of the passageways of the pipes (connecting ends of pipes)
to properly regulate or control the flow of fluids inside our pipes or pipelines, we need valves.
this is made possible with the entry or discharge sides of the pipes being:
 close
– isolation of medium (fluids or substance); to close the flow we give full obstruction from the inside of the valve.
 opened
– allowing large volume of medium to flow; no obstruction from the inside or minimal obstruction
 partially obstructed
– allowing controlled volume of medium to flow
where / at what instance ARE valves used?
– For as long as there is control of fluids or other medium* as well as presence of pressure vessels a valve is necessitated.
 Other medium:
 Slurries
– Solids mixed with liquids usually water where the prime mover is a pump.
 Colloidal solutions
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Solids suspended in gases where the prime mover is a fan/blower.
Pressure vessels (pipes and storage tanks)
– the substance (liquid or gases) they convey or contain are the reason on why they are pressurized.
– the greater quantity or greater volume, the greater the pressure
Valves could not only be found in the industrial or power plant field or operations but could also be found right at our very own homes as
well as in sewerage systems and modern systems.
 At the industrial or power plant field:
– Distribution, regulation, and control of water, oil, gas, and even hazardous substances.
 At our very own homes:
– Distribution, regulation, and control of potable and non-potable water; and regulation of gas pressure.
How are valves classified?
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Valves are classified according to their usage and maybe classified as either any of the following:
Isolation or stop valves
Flow regulation or throttling valves
Back flow prevention valves
Pressure regulation valves (prv)
Pressure relief or safety valves (psv)
Isolation or stop valves
What is isolation or stop valves?
– The isolation of a downstream system from an upstream is critical and necessitates the usage of isolation or stop valves.
– Prevents the flow of medium from one point into another.
– This is done by using a retractable sealing mechanism (gate, disc, plug, ball, flexible material, etc.) totally obstructing the flow’s
passageway.
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Isolation or stop valves possess “tight shut-off” (no leakage or tolerable leakage) when fully closed and “minimum restriction to flow”
(fluid friction taking on the inside should be on a very low value) when fully opened.