Sealing detection device of power station valve

Abstract

A sealing detection device for a power station valve belongs to the technical field of power station valve detection, aims to overcome the defect that ultrasonic leakage detection equipment is difficult to use to perform leakage detection on the surface of a large valve body in the sealing detection process of an existing power station valve, and comprises a bottom support plate, an air tightness test bed, a fixed clamping plate, a sliding clamping plate and an exhaust pipe, the device comprises an air tightness test bench, a fixed clamping plate, a hydraulic push rod and a water tank, and further comprises two ultrasonic leak detection units and an ultrasonic leak detection unit console, the two ultrasonic leak detection units are oppositely arranged on the two sides of the fixed clamping plate, and the ultrasonic leak detection unit console is arranged near the air tightness test bench and connected with the two ultrasonic leak detection units through electric signals. The ultrasonic leak detection unit console is used for controlling the working states of the two ultrasonic leak detection units, and the detection device detects surface leak points of the detected power station valve through the two ultrasonic leak detection units. The device is mainly used for sealing the large-scale power station valve and detecting the leakage point of the valve body.

Description

Technical Field

[0001] This utility model belongs to the field of power plant valve testing technology, specifically relating to a sealing testing device for power plant valves. Background Technology

[0002] Large power plant valves are critical components in power plant systems, and their sealing performance directly affects the safe operation and energy efficiency of the power plant. Currently, existing valve sealing tests for large power plants typically include testing the valve's tightness when closed and detecting leaks on the valve body surface. The testing equipment includes a testing fixture, an airtightness testing bench, and a leak detection system. When testing large valves, a hoisting device is usually used to lift the valve to be tested into the testing fixture, which then secures the valve. The valve's inlet and outlet ends are connected to the airtightness testing bench and an external water tank, respectively. When the valve is closed, a certain pressure of gas is supplied to the valve's inlet end through the airtightness testing bench, and the presence of bubbles in the external water tank is observed. The presence of bubbles indicates gas passage, and the valve's sealing performance is unsatisfactory. The absence of bubbles indicates no gas passage and a good valve seal. For leak detection, there are generally two methods: one is to submerge the entire valve in a water tank and test it using an airtightness testing bench. One method involves pressurizing the air inlet of a power station valve and observing whether bubbles are generated in a water tank while the valve is in the open state. If no bubbles are generated, it indicates that there is no leak; otherwise, it indicates that the valve body itself has a leak. The advantage of this method is that it is convenient and relatively intuitive. The disadvantage is that it is complex in structure, costly, and difficult to accurately determine the location of the leak. Another method involves coating the valve body surface with soapy water and pressurizing the air inlet of the power station valve on an airtightness test bench to observe whether bubbles are generated in the soapy water film on the valve body surface. If bubbles are present, it indicates that the valve body itself has a leak; if no bubbles are present, it indicates that there is no leak. The advantage of this method is that it can more accurately determine the leak point of the valve body. The disadvantage is that the soapy water needs to be applied manually, and the inspector's field of vision is limited, making it impossible to observe the bubble generation on both sides of the valve body at the same time. Therefore, it is necessary to repeatedly apply the soapy water during the pressurization and pressure holding period to improve the comprehensiveness of the test, which is very time-consuming and labor-intensive.

[0003] Besides the two detection methods mentioned above, ultrasonic leak detection equipment can also be used to locate leaks. Generally, ultrasonic leak detection equipment is used to detect leaks at nodes in pipeline systems or small valves. Because the probe of ultrasonic leak detection equipment requires manual control, it is difficult to perform a comprehensive inspection of large valves by manually moving the probe, especially at the bottom of the valve body. From a safety perspective, it is absolutely forbidden for personnel to put their hands under the valve body, as a failure in the valve body clamping could cause the valve body to fall directly onto the inspector's arm, resulting in a serious safety accident. Therefore, ultrasonic leak detection has not yet been applied to the inspection of valves in large power plants. However, ultrasonic leak detection has certain technical advantages compared to the two traditional leak detection methods. Firstly, ultrasonic leak detection is a non-contact detection method with high accuracy, making it easy to accurately determine the leak point. Therefore, developing a sealing detection device for power plant valves is very much in line with practical needs, enabling the application of ultrasonic leak detection in the sealing inspection of large power plant valves. Utility Model Content

[0004] This invention aims to address the drawback of ultrasonic leak detection equipment requiring manual control of the probe end, which makes it inconvenient to use such equipment to detect leaks on the surface of large valve bodies during the sealing inspection of large power plant valves. Therefore, this invention provides a sealing inspection device for power plant valves.

[0005] A sealing testing device for power plant valves includes a bottom support plate, an airtightness test bench, a fixed clamping plate, a sliding clamping plate, an exhaust pipe, a hydraulic push rod, and a water tank. The bottom support plate is fixed to the ground in the working area. The airtightness test bench is fixed to the top of the bottom support plate. The fixed clamping plate is disposed on one side of the airtightness test bench. The output pipe of the airtightness test bench is inserted into the fixed clamping plate and communicates with the clamping side of the fixed clamping plate. The sliding clamping plate is disposed opposite to the fixed clamping plate and is slidably connected to the bottom support plate. The hydraulic push rod is disposed on the side of the sliding clamping plate away from the fixed clamping plate. Furthermore, the hydraulic push rod serves as a power source to drive the sliding clamp to move closer to or further away from the fixed clamp. The water tank is set on the bottom support plate and contains the test liquid. The exhaust pipe is set between the water tank and the sliding clamp, and the exhaust end of the exhaust pipe extends below the liquid surface of the test liquid in the water tank. The air inlet end of the exhaust pipe is inserted into the sliding clamp and connected to the clamping side of the sliding clamp. The power station valve under test is clamped between the fixed clamp and the sliding clamp, and the air inlet end of the power station valve under test is connected to the output pipe of the air tightness test bench. The air outlet end of the power station valve under test is connected to the exhaust pipe.

[0006] The testing device also includes two ultrasonic leak detection units and an ultrasonic leak detection unit control console. The two ultrasonic leak detection units are arranged opposite each other on both sides of the fixed clamp, and the detection end of each ultrasonic leak detection unit is set towards the area between the fixed clamp and the sliding clamp. The ultrasonic leak detection unit control console is set near the airtightness test bench and is connected to both ultrasonic leak detection units by electrical signal. The ultrasonic leak detection unit control console is used to control the working status of the two ultrasonic leak detection units. The testing device uses the two ultrasonic leak detection units to detect the external leakage points of the power station valve under test.

[0007] Furthermore, two slide rails are fixedly connected to the bottom support plate. The two slide rails are arranged parallel to each other along the center line of the width direction of the bottom support plate. The bottom of the sliding clamp has two grooves that are corresponding to and cooperate with the slide rails. The sliding clamp is slidably connected to the slide rails through the two grooves.

[0008] Furthermore, the hydraulic push rod is set between the two slides, and the cylinder of the hydraulic push rod is detachably connected to the top of the bottom support plate through the mounting seat. The piston rod end of the hydraulic push rod is detachably connected to the sliding clamp plate through bolts. As the piston rod in the hydraulic push rod extends or retracts, it drives the sliding clamp plate to move closer to or further away from the fixed clamp plate.

[0009] Furthermore, the ultrasonic leak detection unit includes an ultrasonic leak detector, an X-axis motion component, and a YZ-axis motion component. The X-axis motion component is located on one side of the fixed clamping plate and is fixed to the bottom support plate. The YZ-axis motion component is fixed to the movable end of the X-axis motion component. The X-axis motion component acts as a power source to drive the YZ-axis motion component to move along the length of the bottom support plate. The ultrasonic leak detector is installed on the movable end of the YZ-axis motion component, and the YZ-axis motion component acts as a power source to drive the detection end of the ultrasonic leak detector to move toward the direction of the tested power station valve clamped between the fixed clamping plate and the sliding clamping plate.

[0010] Furthermore, the X-axis motion assembly includes a drive motor, a coupling, a lead screw, a nut slider, and two bearing seats with bearings. The lead screw is located on one side of the fixed clamping plate, and the length extension direction of the lead screw is the same as the length direction of the bottom support plate. The lead screw is supported and fixed on the bottom support plate by the two bearing seats with bearings. The drive motor is located at one end of the lead screw, and the power output shaft of the drive motor is connected to one end of the lead screw through the coupling. The nut slider is sleeved on the lead screw and threadedly connected to the lead screw. The drive motor serves as a power source to drive the lead screw to rotate, thereby causing the nut slider to reciprocate along the axial direction of the lead screw. The YZ-axis motion assembly is installed on the top of the nut slider and moves synchronously with the nut slider.

[0011] Furthermore, the YZ motion assembly includes a first push rod motor, a mounting plate, a fixed base, a second push rod motor, and an ultrasonic leak detector mounting bracket. The first push rod motor is vertically mounted on top of the nut slider. The mounting plate includes a first horizontal section, a vertical section, and a second horizontal section. The first and second horizontal sections are respectively located on both sides of the vertical section. The first horizontal section is located near the top of the vertical section, and the second horizontal section is located near the bottom of the vertical section. Both the first and second horizontal sections are integrally formed with the vertical section. The first horizontal section is located on the piston rod end of the first push rod motor and passes through... The bolt is fixedly connected to the piston rod of the No. 1 push rod motor. The fixed seat is set on the No. 2 horizontal part and fixedly connected to the No. 2 horizontal part. The No. 2 push rod motor is embedded in the fixed seat and is detachably connected to the fixed seat by locking bolts. The piston rod end of the No. 2 push rod motor is set towards the valve of the power station being tested. The leak detector mounting bracket is set on the vertical part and fixedly connected to the vertical part. The body of the ultrasonic leak detector is embedded in the leak detector mounting bracket. The probe end of the ultrasonic leak detector is installed on the piston rod end of the No. 2 push rod motor through the mounting assembly. The probe end of the ultrasonic leak detector is connected to the body of the ultrasonic leak detector through wires.

[0012] Furthermore, the mounting components include a servo mechanism and a probe holder. The housing of the servo mechanism is detachably connected to the piston rod end of the second push rod motor by bolts. The probe holder is mounted on the rotating shaft of the servo mechanism and rotates synchronously with the rotating shaft of the servo mechanism. The probe end of the ultrasonic leak detector is mounted on the probe holder.

[0013] The beneficial effects of this application compared to the prior art are:

[0014] This application provides a sealing detection device for power plant valves. A motion module constructed from X-axis and YZ-axis motion components replaces manual movement of the ultrasonic detector probe, allowing the probe to extend to the bottom of the valve body for leak detection. This improves the flexibility of the ultrasonic probe movement and enables the detection of valve body leaks in large valves using ultrasonic leak detection. It also improves the sealing detection requirements for power plant valves and pioneers the use of ultrasonic leak detection for large power plant valves. Two ultrasonic leak detection units on the front and rear sides can comprehensively inspect the external contour of the valve body, ensuring the accuracy of the leak detection range. Furthermore, compared to submersible or coating-based leak detection, ultrasonic leak detection is a non-contact method, which helps protect the valve body surface. It also has strong anti-interference capabilities, high sensitivity, and can detect minute leaks on the valve body surface, ensuring the accuracy of leak detection. Attached Figure Description

[0015] Figure 1 This is a front view schematic diagram of the sealing detection device described in this application;

[0016] Figure 2This is a side view of the sealing detection device described in this application;

[0017] Figure 3 This is a schematic diagram of the ultrasonic leak detection unit in the sealing detection device described in this application;

[0018] Figure 4 This is a schematic diagram of the YZ-direction motion component in the sealing detection device described in this application;

[0019] Figure 5 This is a schematic diagram of the initial state of the ultrasonic leak detection unit in the sealing detection device described in this application;

[0020] Figure 6 This is a schematic diagram showing the working state of the ultrasonic leak detection unit in the sealing detection device described in this application;

[0021] Figure 7 This is a schematic diagram showing the working state of the ultrasonic leak detection unit in the sealing detection device described in this application;

[0022] In the diagram: 1. Bottom support plate; 2. Air tightness test bench; 3. Fixed clamping plate; 4. Sliding clamping plate; 5. Exhaust pipe; 6. Hydraulic push rod; 7. Slide rail; 8. Water tank; 9. Ultrasonic leak detection unit; 91. Drive motor; 92. Coupling; 93. Bearing housing with bearing; 94. Lead screw; 95. Nut slider; 96. Push rod motor No. 1; 97. Mounting plate; 98. Fixed base; 99. Push rod motor No. 2; 910. Ultrasonic leak detector mounting bracket; 911. Ultrasonic leak detector; 912. Servo motor; 913. Probe bracket; 10. Valve of the power station under test; and 11. Control console of the ultrasonic leak detection unit. Detailed Implementation

[0023] Specific implementation method one: Combining Figures 1 to 7This embodiment provides a sealing testing device for power plant valves. The testing device includes a bottom support plate 1, an airtightness test bench 2, a fixed clamping plate 3, a sliding clamping plate 4, an exhaust pipe 5, a hydraulic push rod 6, and a water tank 8. The bottom support plate 1 is fixed to the ground in the working area. The airtightness test bench 2 is fixed to the top of the bottom support plate 1. The fixed clamping plate 3 is disposed on one side of the airtightness test bench 2. The output pipe of the airtightness test bench 2 is inserted into the fixed clamping plate 3 and communicates with the clamping side of the fixed clamping plate 3. The sliding clamping plate 4 is disposed opposite to the fixed clamping plate 3 and is slidably connected to the bottom support plate 1. The hydraulic push rod 6 is disposed on the sliding clamping plate 4 away from the fixed clamping plate 8. On one side of the clamping plate 3, and the hydraulic push rod 6 as the power source, the sliding clamping plate 4 is moved towards or away from the fixed clamping plate 3. The water tank 8 is set on the bottom support plate 1. The water tank 8 contains the test liquid. The exhaust pipe 5 is set between the water tank 8 and the sliding clamping plate 4. The exhaust end of the exhaust pipe 5 extends below the liquid surface of the test liquid in the water tank 8. The air inlet end of the exhaust pipe 5 is inserted into the sliding clamping plate 4 and connected to the clamping side of the sliding clamping plate 4. The power station valve 10 under test is clamped between the fixed clamping plate 3 and the sliding clamping plate 4. The air inlet end of the power station valve 10 under test is connected to the output pipe of the air tightness test bench 2. The air outlet end of the power station valve 10 under test is connected to the exhaust pipe 5.

[0024] The testing device also includes two ultrasonic leak detection units 9 and an ultrasonic leak detection unit control console 11. The two ultrasonic leak detection units 9 are arranged opposite each other on both sides of the fixed clamping plate 3, and the detection end of each ultrasonic leak detection unit 9 is set towards the area between the fixed clamping plate 3 and the sliding clamping plate 4. The ultrasonic leak detection unit control console 11 is set near the airtightness test bench 2 and is connected to both ultrasonic leak detection units 9 by electrical signal. The ultrasonic leak detection unit control console 11 is used to control the working status of the two ultrasonic leak detection units 9. The testing device detects the external leakage points of the power station valve 10 under test through the two ultrasonic leak detection units 9.

[0025] Two slide rails 7 are also fixed on the bottom support plate 1. The two slide rails 7 are arranged parallel to each other along the center line of the width direction of the bottom support plate 1. The bottom of the sliding clamp 4 is machined with two slide grooves that correspond to and cooperate with the slide rails 7. The sliding clamp 4 is slidably connected to the slide rails 7 through the two slide grooves.

[0026] The hydraulic push rod 6 is set between two slide rails 7, and the cylinder of the hydraulic push rod 6 is detachably connected to the top of the bottom support plate 1 through the mounting seat. The piston rod end of the hydraulic push rod 6 is detachably connected to the sliding clamp 4 by bolts. As the piston rod in the hydraulic push rod 6 extends or retracts, it drives the sliding clamp 4 to move closer to or away from the fixed clamp 3.

[0027] In this embodiment, the airtightness test bench 2 is a Lejun brand QPT-10-MP pressure testing machine, and the main controller of the ultrasonic leak detection unit control console 11 is an AMX-HSE7A-32MR controller manufactured by Aimoxun. The airtightness test bench 2 provides pressurized gas during the sealing test. The ultrasonic leak detection unit control console 11 is mainly used to control the working status and working path of the ultrasonic leak detection unit 9, and to coordinate the synchronous operation of the various power sources in the ultrasonic leak detection unit 9. The detection liquid in the water tank 8 is water, and the slide 7... The sliding clamp 4 is used to guide the movement of the sliding clamp 4 and ensure the accuracy of the movement of the sliding clamp 4 in the direction of the fixed clamp 3. Both the fixed clamp 3 and the sliding clamp 4 are machined with through holes. The through holes on the fixed clamp 3 are sealed and disassembled to the output pipe in the air tightness test bench 2. The through holes on the sliding clamp 4 are sealed and disassembled to the air inlet end of the exhaust pipe 5. Rubber pads are provided on the clamping surfaces of both the fixed clamp 3 and the sliding clamp 4 to ensure the end sealing of the tested power station valve 10 after clamping it.

[0028] Specific Implementation Method Two: Combining Figures 1 to 7 This embodiment further defines the ultrasonic leak detection unit 9 in Specific Embodiment 1. The ultrasonic leak detection unit 9 includes an ultrasonic leak detector 911, an X-axis motion component, and a YZ-axis motion component. The X-axis motion component is disposed on one side of the fixed clamping plate 3 and is fixed on the bottom support plate 1. The YZ-axis motion component is fixed on the movable end of the X-axis motion component. The X-axis motion component acts as a power source to drive the YZ-axis motion component to move along the length direction of the bottom support plate 1. The ultrasonic leak detector 911 is installed on the movable end of the YZ-axis motion component, and the YZ-axis motion component acts as a power source to drive the detection end of the ultrasonic leak detector 911 to move toward the direction of the tested power station valve 10 clamped between the fixed clamping plate 3 and the sliding clamping plate 4.

[0029] The X-axis motion assembly includes a drive motor 91, a coupling 92, a lead screw 94, a nut slider 95, and two bearing seats 93 with bearings. The lead screw 94 is located on one side of the fixed clamping plate 3, and the length extension direction of the lead screw 94 is the same as the length direction of the bottom support plate 1. The lead screw 94 is supported and fixed on the bottom support plate 1 by the two bearing seats 93 with bearings. The drive motor 91 is located at one end of the lead screw 94, and the power output shaft of the drive motor 91 is connected to one end of the lead screw 94 through the coupling 92. The nut slider 95 is sleeved on the lead screw 94 and threadedly connected to the lead screw 94. The drive motor 91 serves as a power source to drive the lead screw 94 to rotate, thereby driving the nut slider 95 to reciprocate along the axial direction of the lead screw 94. The YZ-axis motion assembly is installed on the top of the nut slider 95 and moves synchronously with the nut slider 95.

[0030] The YZ motion assembly includes a first push rod motor 96, a mounting plate 97, a fixed base 98, a second push rod motor 99, and an ultrasonic leak detector mounting bracket 910. The first push rod motor 96 is vertically mounted on top of the nut slider 95. The mounting plate 97 includes a first horizontal section, a vertical section, and a second horizontal section. The first and second horizontal sections are respectively located on both sides of the vertical section. The first horizontal section is located near the top of the vertical section, and the second horizontal section is located near the bottom of the vertical section. Both the first and second horizontal sections are integrally formed with the vertical section. The first horizontal section is located on the piston rod end of the first push rod motor 96 and is bolted to the first push rod motor 99. The piston rod of the 6 is fixedly connected, the fixed seat 98 is set on the second horizontal part and fixedly connected to the second horizontal part, the second push rod motor 99 is embedded in the fixed seat 98 and is detachably connected to the fixed seat 98 by locking bolts, the piston rod end of the second push rod motor 99 is set towards the valve 10 of the power station under test, the leak detector mounting bracket 910 is set on the vertical part and fixedly connected to the vertical part, the body of the ultrasonic leak detector 911 is embedded in the leak detector mounting bracket 910, the probe end of the ultrasonic leak detector 911 is installed on the piston rod end of the second push rod motor 99 through the mounting assembly, and the probe end of the ultrasonic leak detector 911 is connected to the body of the ultrasonic leak detector 911 through wires;

[0031] The mounting assembly includes a servo mechanism and a probe holder 913. The housing of the servo mechanism is detachably connected to the piston rod end of the second push rod motor 99 by bolts. The probe holder 913 is mounted on the rotating shaft of the servo mechanism and rotates synchronously with the rotating shaft. The probe end of the ultrasonic leak detector 911 is mounted on the probe holder 913. Other components and connections are the same as in Specific Embodiment 1.

[0032] In this embodiment, the ultrasonic leak detector 911 is used to detect leaks in the valve body. The ULD-405 ultrasonic leak detector manufactured by Anbo Company is selected. The X-axis motion component and the YZ-axis motion component constitute the motion module of the ultrasonic leak detector 911, which can drive the probe end of the ultrasonic leak detector 911 to move along the contour of the tested power station valve 10, performing comprehensive leak detection on the surface of the valve body of the tested power station valve 10. Considering the working stroke of the remote control module, this application provides ultrasonic leak detection units 9 on both sides of the tested power station valve 10, wherein the X-axis motion component is... The lead screw and nut mechanism is mainly used to move the ultrasonic leak detector 911 along the length of the tested power station valve 10. In the YZ motion assembly, the first push rod motor 96 moves the ultrasonic leak detector 911 along the height of the tested power station valve 10, and the second push rod motor 99 moves the ultrasonic leak detector 911 along the width of the tested power station valve 10. The ultrasonic leak detector mounting bracket 910 mainly supports the main body of the ultrasonic leak detector 911 and positions its control surface outwards for easy operation. The mounting assembly uses... In the probe section of the fixed ultrasonic leak detector 911, the servo mechanism includes at least one servo motor 912, and generally two servo motors can be provided. The first servo motor is bolted to the piston rod end of the second push rod motor 99, and the axis of rotation of the first servo motor is aligned with the length extension direction of the bottom support plate 1. The housing of the second servo motor is fitted onto the rotation axis of the first servo motor, and the axis of rotation of the second servo motor is vertically upward. The probe holder 913 is a claw-type probe mounting structure, fitted onto the rotation axis of the second servo motor and swinging synchronously with the rotation axis of the second servo motor. The probe holder 913 can be rotated in three dimensions by the coordinated operation of two servo motors to ensure that the probe end is always facing the test surface of the power station valve 10. The drive motor 91, the first push rod motor 96, the second push rod motor 99 and the two servo motors 912 are all connected to the ultrasonic leak detection unit control console 11 by electrical signals. The ultrasonic leak detection unit control console 11 is used to control the working status of the drive motor 91, the first push rod motor 96, the second push rod motor 99 and the two servo motors 912 to achieve precise control of the working position of the probe end in the ultrasonic leak detector 911.

[0033] The present invention has been disclosed above with reference to preferred embodiments, but it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed structure and technical content to create equivalent embodiments without departing from the scope of the present invention. However, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

[0034] Working principle

[0035] In use, the various components are first assembled according to the connection relationships described in Embodiment 1 and Embodiment 2. The tested power station valve 10 is then hoisted between the fixed clamping plate 3 and the sliding clamping plate 4 using a hoisting device. A hydraulic push rod 6 pushes the sliding clamping plate 4 closer to the fixed clamping plate 3 to clamp the valve 10 at both ends. The valve is then closed. Pressurized gas is introduced into the tested power station valve 10 through the airtightness test bench 2 and the gas supply system. The gas pressure is 1.1 times the maximum permissible working pressure of the tested valve. The inflation period is 10 seconds, and the pressure holding test is conducted between 120 and 150 seconds. Observe whether bubbles are generated in the test liquid in pool 8. If no bubbles are generated, it indicates that the valve body is sealed properly. Turn off the air supply and open the valve at the same time to ensure that the valve 10 of the tested power station is open. At this time, pressurize and supply air, and make the ultrasonic leak detection unit 9 move the probe of the ultrasonic leak detector 911 along the contour of the valve 10 of the tested power station according to the preset detection route. Ensure that the probe end and the valve body always maintain a working gap of 5-10mm. When the ultrasonic leak detector 911 detects a leak point on the surface of the valve body, it will produce a prompt beep. The staff can accurately judge the leak point on the surface of the valve body through the feedback of the prompt sound, so as to facilitate recording and subsequent maintenance.

Claims

1. A sealing detection device for power station valves, the detection device comprising a bottom support plate (1), an air tight test bench (2), a fixed clamping plate (3), a sliding clamping plate (4), an exhaust pipe (5), a hydraulic push rod (6) and a water pool (8), the bottom support plate (1) is fixed on the ground of a working area, the air tight test bench (2) is fixed on the top of the bottom support plate (1), the fixed clamping plate (3) is arranged on one side of the air tight test bench (2), an output pipe of the air tight test bench (2) is inserted into the fixed clamping plate (3) and is arranged in communication with the clamping side of the fixed clamping plate (3), the sliding clamping plate (4) is arranged opposite to the fixed clamping plate (3) and is slidably connected with the bottom support plate (1), the hydraulic push rod (6) is arranged on the side of the sliding clamping plate (4) away from the fixed clamping plate (3), and the hydraulic push rod (6) drives the sliding clamping plate (4) to move towards or away from the fixed clamping plate (3), the water pool (8) is arranged on the bottom support plate (1), the water pool (8) contains a detection liquid, the exhaust pipe (5) is arranged between the water pool (8) and the sliding clamping plate (4), and the exhaust end of the exhaust pipe (5) extends below the liquid level of the detection liquid in the water pool (8), the air inlet end of the exhaust pipe (5) is inserted into the sliding clamping plate (4) and is arranged in communication with the clamping side of the sliding clamping plate (4), the power station valve (10) to be detected is clamped between the fixed clamping plate (3) and the sliding clamping plate (4), and the air inlet end of the power station valve (10) to be detected is arranged in communication with the output pipe of the air tight test bench (2), and the air outlet end of the power station valve (10) to be detected is arranged in communication with the exhaust pipe (5). characterized in that The detection device further comprises two ultrasonic leak detection units (9) and an ultrasonic leak detection unit console (11), the two ultrasonic leak detection units (9) are arranged opposite to each other on the two sides of the fixed clamping plate (3), and the detection end of each ultrasonic leak detection unit (9) is arranged towards the area between the fixed clamping plate (3) and the sliding clamping plate (4), the ultrasonic leak detection unit console (11) is arranged near the air tight test bench (2) and is connected with the two ultrasonic leak detection units (9) through electrical signals, and the ultrasonic leak detection unit console (11) is used for controlling the working state of the two ultrasonic leak detection units (9), and the detection device detects the external leakage points of the power station valve (10) to be detected through the two ultrasonic leak detection units (9).

2. A seal detection device for a power plant valve according to claim 1, characterized in that: Two slides (7) are further fixedly connected to the bottom support plate (1), the two slides (7) are arranged in parallel opposite to each other along the center line of the width direction of the bottom support plate (1), two sliding grooves corresponding to the slides (7) are arranged on the bottom of the sliding clamping plate (4), and the sliding clamping plate (4) is slidably connected with the slides (7) through the two sliding grooves.

3. A seal detection device for a power plant valve according to claim 2, characterised in that: The hydraulic push rod (6) is arranged between the two slides (7), and the cylinder body of the hydraulic push rod (6) is detachably connected with the top of the bottom support plate (1) through a mounting seat, and the piston rod end of the hydraulic push rod (6) is detachably connected with the sliding clamp plate (4) through bolts, and the sliding clamp plate (4) is driven to move towards or away from the fixed clamp plate (3) along with the extension or contraction of the piston rod in the hydraulic push rod (6).

4. A seal detection device for a power plant valve according to claim 3, characterised in that: The ultrasonic leak detection unit (9) comprises an ultrasonic leak detector (911), an X-direction motion assembly and a YZ-direction motion assembly, the X-direction motion assembly is arranged on one side of the fixed clamp plate (3) and is fixed on the bottom support plate (1), the YZ-direction motion assembly is fixed on the movable end of the X-direction motion assembly, the X-direction motion assembly drives the YZ-direction motion assembly to move along the length direction of the bottom support plate (1) as a power source, and the ultrasonic leak detector (911) is installed on the movable end of the YZ-direction motion assembly, and the YZ-direction motion assembly drives the detection end of the ultrasonic leak detector (911) to move towards the direction of the measured valve (10) clamped between the fixed clamp plate (3) and the sliding clamp plate (4).

5. A seal detection device for a power plant valve according to claim 4, characterised in that: The X-direction motion assembly comprises a driving motor (91), a coupling (92), a lead screw (94), a nut block (95) and two bearing-equipped bearing seats (93), the lead screw (94) is arranged on one side of the fixed clamp plate (3), and the length extension direction of the lead screw (94) is the same as the length direction of the bottom support plate (1), the lead screw (94) is supported and fixed on the bottom support plate (1) through the two bearing-equipped bearing seats (93), the driving motor (91) is arranged on one end of the lead screw (94), and the power output shaft of the driving motor (91) is connected with one end of the lead screw (94) through the coupling (92), the nut block (95) is sleeved on the lead screw (94) and is in threaded connection with the lead screw (94), the driving motor (91) drives the lead screw (94) to rotate and in turn drives the nut block (95) to reciprocate along the axial direction of the lead screw (94) as a power source, and the YZ-direction motion assembly is installed on the top of the nut block (95) and moves synchronously with the nut block (95).

6. A seal detection device for a power plant valve according to claim 5, characterised in that: The YZ direction movement assembly comprises a first push rod motor (96), a mounting plate (97), a fixing seat (98), a second push rod motor (99) and an ultrasonic leak detector mounting rack (910), the first push rod motor (96) is vertically arranged on the top of the nut sliding block (95), the mounting plate (97) comprises a first horizontal part, a vertical part and a second horizontal part, the first horizontal part and the second horizontal part are arranged on the two sides of the vertical part respectively, the first horizontal part is arranged close to the top of the vertical part, the second horizontal part is arranged close to the bottom of the vertical part, and the first horizontal part and the second horizontal part are integrally arranged with the vertical part, the first horizontal part is arranged on the piston rod end of the first push rod motor (96) and is fixedly connected with the piston rod of the first push rod motor (96) through a bolt, the fixing seat (98) is arranged on the second horizontal part and is fixedly connected with the second horizontal part, the second push rod motor (99) is embedded in the fixing seat (98) and is detachably connected with the fixing seat (98) through a locking bolt, the piston rod end of the second push rod motor (99) is arranged towards the measured power station valve (10), the leak detector mounting rack (910) is arranged on the vertical part and is fixedly connected with the vertical part, the body of the ultrasonic leak detector (911) is embedded on the leak detector mounting rack (910), the probe end of the ultrasonic leak detector (911) is arranged on the piston rod end of the second push rod motor (99) through the mounting assembly, and the probe end of the ultrasonic leak detector (911) is connected with the body of the ultrasonic leak detector (911) through a wire.

7. A seal detection device for a power plant valve according to claim 6, characterised in that: The mounting assembly comprises a rudder mechanism and a probe rack (913), the shell of the rudder mechanism is detachably connected with the piston rod end of the second push rod motor (99) through a bolt, the probe rack (913) is sleeved on the rotating shaft of the rudder mechanism and rotates synchronously with the rotating shaft of the rudder mechanism, and the probe end of the ultrasonic leak detector (911) is arranged on the probe rack (913).

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