A
D c c e t t o e u c c s s t t t t o i i c c r r
B o i i l l e r r T u b e L e a k k
P r r o d u c t t C a t t a l l o g
Address: 30/F Zhongshen Garden Building, Caitian Road,
Shenzhen, China 518026.

339 Castle Peak Road, Rm 2715,Kowloon,Hong Kong.
Tel: 852-2194-9216 Fax: 852-2725-7921
E-mail: wkwong@hknet.com
List of Contents
I
Introduction ……………………………… 3
II
Working Principle …………………..…… 4
III System Performance …………………..… 5
IV System Component ……………………… 5
V Advantage of the System ……………… 6
VI Software Description ………………….… 8
VII Operating Description …………………… 9
VIII Introduction to Installation ………………10
IX
Operating Benefit ………………………..13
X After Sale Service ……………….…………13
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I.
I I n t t r r o d u c t t i i o n t t o A u t t o m a t t i i c B o i i l l e r r
T u b e L e a k A l l a r r m S y s t t e m
Introduction:
Following the modern development of the power generation, the power plant boilers are entering the age of large capacity and high pressure. The number of tubes in boilers increases continuously.
The operation reliability requirements also increase considerably.
The boiler tube leak occurrence can directly affect safe and economic operation of the generating units. Due to this fact, the prevention and early detection of the boiler tube leak become more important.
The Automatic Boiler Tube Leak Detection and Alarm System utilize Acoustic signal measurements and processing technique to detect and provide early warning of the leaks of four types of boiler tubes (Water Wall tubes, Superheater tubes, Reheater tubes and Economizer Tubes). Various suppliers have started to develop early warning of tube leaks in the 80s. More detector products became more readily available. In 1990s, most of the large capacity boilers have already had boiler tube leak detection. The
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technology and capability of the tube leak detection became more mature and reliable. The Boiler Tube Leak Detection system captures the sound signal inside the boiler. The sound signals are then converted into spectrum by using Fast Fourier Transform
(FFT) technique. Based on the frequency spectrum of the sound signal, tube leak can be identified and traced. When the tube leak sound frequency signal reaches an alarm level, audible alarm will be produced to warn the operators. This system can also monitor the normal operation of the Soot-blowing process.
II.
Working Principle:
Area of Application: This equipment is suitable for Fossil Fired
Power Station Boilers real time monitoring of early boiler tube leak and soot-blowing operation of the Wall tubes, Superheaters,
Reheaters and Economizer Tubes.
Basic Principle: Utilizes Acoustic principle with the enhanced sound wave sensors to capture the sound signal within the boiler. The sensors convert the sound signal into electrical current signal. The monitoring system uses FFT technique to convert the sound signal into frequency spectrum and display in the form of bar chart. The analysis is based on the continuous intensity of the sound at a particular frequency to tell whether it is a tube leak.
Function Accomplished :
1.
Real time Tube Leak Monitoring and Early Warning Alarm:
When Boiler tubes (Wall Tube, Superheater, Reheater,
Economizer tubes) have blowholes or cracks, the system will alarm depending on the seriousness. During the leak monitoring,
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the bar chart display changes color to represent: Normal (Green),
Abnormal (Orange), Leak (Red).
2.
Accurate Tube Leak Area Identification: Based on various sensor locations, intensity of the leak in each location and the sequence of the leak in each location, the tube leak area can be identified.
The valid range of tube leak detection of each sensor is about 4 meters.
3.
Display Tube Leak Sound Spectrum: The VDU displays the sound spectrum in the frequency range of 0 – 15 KHz. Within this range, one can tell whether it is tube leak or steam/air sootblowing.
4.
Trace Tube Leak Trend: There are curves to trace the trend of the tube leak developments. This can reflect the intensity of the tube leak and can record for a long term monitoring and printing.
Data can be stored up to 12 months’ record.
5.
Real Time Monitoring of the Furnace Sound: The operator can select any sensor location to listen to the sound in the Furnace.
Recording interface is also provided.
6.
Monitor Soot-blowing Operation:

Monitor whether the Soot-blowing Air source pressure is normal : Start Soot-blowing sequence, the bar chart in the location of soot-blowing should be more than 65%.
Otherwise, the air source pressure is considered as either insufficient or Sound Pipe blockage.

Monitor whether the Soot-blower is rotating: When the
Soot-blower is rotating, the bar chart display should show a regular pattern of changing intensity in the vicinity of sootblowing. Otherwise, the system should be considered not working.
 Monitor whether the Soot-blower is stuck: When the Sootblower is retracted, the bar chart display should show the intensity before soot-blowing, otherwise, the system will alarm and the operator should inspect the soot-blowing system to prevent tube damage.
7.
Communication Capability with DCS System: After the Tube
Leak System formed a two way communications with the
DCS computer, the DCS can display the status of the leak detection which can be activated by single clicking a pushbutton
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“Leak
Inspection” with a mouse. The
DCS can send a signal to the Tube
Leak computer to retrieve the necessary data in 3 seconds’ interval. The DCS Operator (or I/O) station can continuously receive real time data. With the retrieved data, the DCS
Operator station can display the data in accordance with the data stored in its historical database for history data retrieval. A single click of ‘Exit’ can exit the system back to its original display. The communication is based on RS-232C standard.
8.
Remote Communication Capability: Through the telephone cable
(PSTN) and the modem, we can install communication line between the power station Acoustic Leak Detection System and the supplier’s service team to monitor the system operation, to diagnose as well as to maintain the system remotely.
9.
Self-Diagnostic Function: Press the ‘Test’ soft button, the system can display and diagnose whether the system is running normally.
10.
Auto Soot Clearance of Sound Pipe:
10.1
Clearing of Soot: Clearing of soot from the Sound Pipe can be done either manually or automatically.
10.2
Determination of Sound Pipe Blockage: The free path of
Sound Pipe determines the reliability of the system operation. The software can determine whether the Sound
Pipe is blocked in real time. If the Sound Pipe is free, the
Display mimic will show a blue color indicating normal condition. If the Sound Pipe is blocked, the display mimic will show red color indicating blockage.
10.3
Sound Pipe Blockage Alarm: When the Sound Pipe is seriously blocked, the system will produce a hardwired alarm through the alarm facia. This can warn the operator to clear the blockage by using the Ash clearing motor or even to clear the ash manually in serious situation.
III.
System Performance
Whole Installation :
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IV.
1.
Sensitivity: Able to detect less than 2 mm. Of blow-holes.
2.
Valid Range: The maximum of each sensor is up to 4 m. radius of hemispherical range.
3.
Continuous Operation: More than 20,000 hours.
Equipment:
1.
Enhanced Sound Sensor:

Sensitivity>2mV/Pa,

Output Current: 4-20mA (AC)

Detection Range: R< 12 m. hemispherical maximum

Working Temperature: -25

C to +105

C ；
 Continuous Operating Time: more than 30,000 hours.
2.
Leakage Detection Alarm System

Input Channel: 32

Computer: PIII Industrial computer, 20Gb Hard disk,
64Mb RAM, 1.4Mb floppy disk,

12-bit A/D converter, sampling frequency 100 KHz,
Historical data storage for 12 months.
 UPS and reliable industrial power supply.
Expansion : It is possible to share one system for several generating units.
System Component
Equipment List (for 300MW Unit)
1.
Motorized type Sound Pipe: model V and L 24 sets
2.
Enhanced Sound Sensors: model XLC 24 pcs.
3.
Alarm and Display System: 1 set
Model GD/XLD with a Main Frame
(Industrial computer PIII CPU, 64
Mb RAM, 20Gb hard disk, color display with touch screen, color
Inkjet printer
4.
Control Cabinet: 1 set
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It consists of Mouse, terminals, relays etc.
Material Supply List
1.
Cable: 5 Km (RVVP type, 6 x 0.75mm
2 )
2.
Accessories: 1 set
Flexible conduits, conduits, angle bar and connectors.
Document
1. Technical manuals 5 copies
V.
2. System Software 1 set
Power Supply
220V AC, 50 Hz, 1.5 KW
System Features
1.
Sound Pipe with Motorized Soot Clearing Brush : Sound
Pipe installed on the boiler casing suffer from high temperature and large amount of coal dust. This can block the Sound Pipe.
The system can track the Sound Pipe blockage and alarm in case of blockage. Our company has developed a Sound Pipe with motorized Soot clearing facility. The advantage is easy to install, ease of maintenance and also able to clear soot and slag.
This feature can effectively eliminate the manual labor for clearing the soot and the use of traditional compressed air clearing method. Thus it can eliminate the trouble of laying compressed air pipes, reduce the labor cost of laying copper pipes and maintaining the solenoid valves.
2.
Auto or Remote Manual Soot Clearing : The computer enable to set auto soot clearing once every day, 3 days, 7 days, 10 days and 15 days. This soot clearing period depends on the type of coal burnt and type of boiler.
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V-shape Sound Pipe has two types of configurations.

Round Mouth Type: ФAB = 45mm
 Flat Mouth Type: (AB = 60×10mm)
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3.
Traditional Soot Clearing by Compressed Air : To solve the soot blockage problem on the Sound Pipe, traditionally, compressed air are used to blow through the Sound Pipe for soot clearing purpose. The L shape Sound Pipe has an air connection. Usually, we need several solenoid valves and a net work of pipes for air distribution for auto control of soot clearing similar to the motorized soot clearing process.
L-shape Compressed Air Type Sound Pipe
4.
Enhanced Sound Sensor : This type of sensor combines the pre-amplifier and transmitter together and sealed inside a stainless steel case. This is more convenient to handle and install.
.
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XLC Enhanced Sound Sensor
VI.
Software Description
The Boiler tube leak detection alarm system utilizes powerful structural software Visual C++ running on Windows platform. The special features are shown below:
1.
The software uses standard menu and interface for better communication with the operators. The interface and menu are user friendly and convenient to operate. This can reduce the learning time.
2.
Use scanning method for data collection and conversion.
3.
Use the classical Fast Fourier Transform (FFT) calculation for sound signal conversion from Time domain to Frequency spectrum domain. This can outline the special leak pattern to produce advance warning for a developing early leak.
4.
Use IDEF to build model for accurate leak alarm.
5.
Automatic saving of historical leak data: This can lead to the development of leak warning expert system.
VII.
Operating Description
Based on the system software requirements, the Tube Leak MMI
Display system uses Touch Screen operating method. This can prevent the use of non-standard mouse operation.
1.
After the system is started and display the main menu:
F1 Real time F2 Historical F3Sootblock F4 Monitor F5 Setting
1.Realtime trend
2.
Select F1 to F5 and get into a different sub-menu. For example, when F1 is pressed, it will get into the Real Time
Monitoring menu as follows:
2.Realtime spectrum
3.Realtime Bar 4.Simulated
Furnace
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Then press 1. To 4. For different graphic displays.
3.
In any condition, press Esc can put the system back to the
Main menu.
4.
Press F8 button can start system self-diagnostic.
5.
When any measurement point (or a multiple of points) has a blockage alarm, the system can automatically get into Soot
Clearing screen. The operator can also select time interval from one to 30 days for soot clearing automatically.
Real time Trend Chart
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Real Time Spectrum Chart
VIII. Installation Brief
General Rule of Installation :
Usually, the power station personnel or local installation subcontractor does the installation, and our company can only be responsible for advisory of the required installation and quality control. Our company can be responsible for wiring connection checks and commissioning with the help from the power station personnel.
Condition of Installations: The installation can only be started after the machine shutdown. The testing and commissioning can only be started when the unit is running.
What is to be installed:
 Detecting points Installation: This requires opening the round or rectangular holes on the boiler tube webs. The
Sound Pipes are then welded on the tube web and the insulation materials are restored after the welding.

Control Panel Installation: The control panel can either be installed in the control room or in the equipment room.
Generally, control room is a better choice, as the operator
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can operate on it easily and can view the alarm display.

Cable connections: This includes the connection of the cable from each sensors to the control panel terminal blocks and to the alarm facia as well as from the Soot-blowing
System to the Leak Detection system Main Frame. Either metal conduit or flexible conduit can be used to protect against the mechanical damage to the control and power cable.

Commissioning and Testing: This includes the wire connection from the sensors to the computers and the continuity testing of the connections.
 Installation period: Usually, the installation needs about 8 days to finish and the commissioning needs only 2 days to finish.
18
（
300MW Unit/24 Pts.
)
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Drawing Illustrations
1.
The symbol

represents the location of measuring points.
2.
The numbers inside the symbol

represent the sequence numbers of the location.
3.
Points 3 and 5 are located on the middle of the boiler front wall.
4.
Points 4 and 6 are located on the middle of the boiler rear wall.
5.
Points with odd and even numbers are located symmetrically on the opposite side.
6.
Points with odd numbers are located on the boiler left side wall.
7. Points with even numbers are located on the boiler right side wall.
IX.
The Benefit of Operation : The use of Acoustic Leak Detectors can bring a major impact to the boiler safety and economic operations.
Usually, the cost of such investment can be paid off in a year’s time.
Benefit to Safety Operation
1.
Prevent unplanned Outage, good to the network operatoins.
2.
Prevent or reduce damage to the nearby tubes due to tube leak.
3.
Avoid wrong tube leak alarm due to traditional tube leak detection.
4.
Avoid the accidence caused by the local inspection by operators.
5.
Prevent tube damage caused by Soot-blowing problem.
Benefit to Economic Operation
1.
Reduce time to repair tube leak, reduce work load.
2.
Reduce cost on tube damage due to tube leak.
3.
Improve boiler usability.
4.
Effective monitoring of Soot-blowing operation, improve efficiency.
5.
Good to boiler preventive maintenance.
X.
After Sales Services
1.
Free Maintenance Services within the first year.
2.
Lift Time Maintenance Support.
3.
Ensure Availability of Spare Parts.
4.
Software Upgrade Support.
5.
Local Installation Advisory.
6.
Equipment Commissioning.
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7.
Operation and Maintenance Training.
8.
Routine Inspection of Equipment Operation.
9.
Complete database file on maintenance.
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