Automatic leak detection device for the whole gas flowmeter and its working method

Abstract

The present invention provides an automatic leak detection device for the whole gas flowmeter and its working method, including the following steps; Step S1: Place the gas flowmeter in a cylindrical light-absorbing cover, leaving an optical path gap between the outer wall of the gas flowmeter and the light-absorbing cover, and coat the surface of the gas flowmeter with foam water; Step S2: Set a light output end beside one end of the gas flowmeter and a light receiving end beside the other end, input a low-brightness detection light from the light output end to form an annular cylindrical detection optical path; at the light receiving end, a light focusing device focuses the detection light on the detection point to form a light spot; the light intensity value of the light spot is detected by a light intensity detection circuit at the detection point; Step S3: Fill the gas flowmeter with gas, the gas escapes from the leakage point and forms foam, increasing the light attenuation of the detection optical path. When the attenuation amplitude of the light intensity of the light spot is greater than the threshold within a preset time period, it is determined that there is a leak on the outer wall of the gas flowmeter; The present invention can automatically perform leak detection and evaluation on the whole gas flowmeter.

Description

Technical Field

[0001] The present invention relates to the technical field of detection equipment, in particular to an automatic leak detection device for the whole gas flowmeter and its working method. Background Art

[0002] When a gas flowmeter is subjected to a leak detection experiment, while introducing gas into the sealed gas flowmeter, foam water is sprayed on the outer surface, and it is observed whether there are bubbles on the outer surface of the gas flowmeter to determine whether the gas flowmeter leaks. However, in the traditional technology, this requires manual visual observation and is difficult to automate.

[0003] In addition, the foam water sprayed by the traditional leak detection device is easy to splash and flow to the ground, affecting the environment of the operation site. Summary of the Invention

[0004] The present invention provides an automatic leak detection device for the whole gas flowmeter and its working method, which can automatically evaluate the leak of the whole gas flowmeter by detecting the change of the light intensity of the detection light path.

[0005] The present invention adopts the following technical solutions.

[0006] A working method for an automatic leak detection device for the whole gas flowmeter, the working method includes the following steps;

[0007] Step S1: Place the gas flowmeter to be tested in a cylindrical light-absorbing cover, leaving a light path gap between the outer wall of the gas flowmeter and the light-absorbing cover, and coat the surface of the gas flowmeter with foam water;

[0008] Step S2: Set a light output end beside one end of the gas flowmeter and a light receiving end beside the other end. Input a low-brightness detection light from the light output end, and the detection light forms an annular columnar detection light path adjacent to and parallel to the outer wall of the light-absorbing cover; at the light receiving end, a light focusing device focuses the detection light on the detection point to form a light spot; the light intensity detection circuit detects the light intensity value of the light spot at the detection point;

[0009] Step S3: Fill the gas flowmeter with gas. If there is a leakage point on the outer wall of the gas flowmeter, the gas will escape from the leakage point and form foam. The foam increases the light attenuation of the detection light path by refracting the detection light, reflecting the detection light or absorbing the detection light. When the attenuation amplitude of the light intensity of the light spot detected by the light intensity detection circuit is greater than the threshold within a preset time period, it is determined that there is a leak on the outer wall of the gas flowmeter.

[0010] The light intensity detection circuit includes a single-chip microcomputer, a photosensitive resistor, and a triode connected thereto; the light-receiving surface of the photosensitive resistor is irradiated by the light spot at the detection point; the output voltage of the collector of the triode is input to the A / D converter of the single-chip microcomputer; the single-chip microcomputer evaluates the light intensity value of the light spot to determine whether there is a leakage point in the currently detected gas flowmeter.

[0011] An absorbent layer is provided on the inner wall of the light-absorbing cover; when the detection light is infrared light, the foam can absorb the infrared light.

[0012] The foam water is dark-colored foam water, and its components, in addition to the pigment component, further include the following components: 30% nonylphenol polyoxyethylene ether NP-10, 10% glycerol, 2% CMC, 0.01% brilliant blue, and the balance is water.

[0013] The working method further includes step S4, the content of which is to open the light-absorbing cover, and when there is a leakage point on the outer wall of the gas flowmeter and there is a large amount of foam at this point, use a ventilation device to blow away the foam at the gas flowmeter.

[0014] The ventilation device includes an air outlet device and an air suction device separately arranged on both sides of the light-absorbing cover. After the air outlet device blows down the foam at the gas flowmeter, the air suction device sucks in the blown-down foam to prevent pollution of the test environment.

[0015] An automatic leak detection device for the whole gas flowmeter includes a frame. On the frame, there is an upper sealing press block for abutting against the upper flange of the gas flowmeter. Directly below the upper sealing press block, there is a lower sealing press block for abutting against the lower flange of the gas flowmeter. A water receiving tray is arranged on the outer peripheral side of the lower sealing press block. Above the water receiving tray, a lifting cover cylinder for surrounding the gas flowmeter coaxially is arranged. Inside the lifting cover cylinder, there is a nozzle for spraying foam water towards the gas flowmeter. An air inlet is provided on the upper sealing press block or the lower sealing press block; the lifting cover cylinder is a light-absorbing cover.

[0016] The frame includes a base. At least two vertical guide rods are fixedly connected to the base. The guide rods all pass through the guide holes of a lifting seat body arranged above the base. The lifting seat body is driven to lift by a hydraulic cylinder installed on the frame. The lower sealing press block is installed on the top surface of the base, and the upper sealing press block is installed on the bottom surface of the lifting seat body.

[0017] The lower sealing press block is installed on the top surface of the base of the frame through a rotating shaft and is driven by a motor to rotate actively. The upper sealing press block is installed on the bottom surface of the lifting seat body through a rotating shaft to rotate passively.

[0018] The lower sealing press block is installed on the top surface of the base of the frame. The water receiving tray is an annular structure with an upward-facing opening and is coaxially connected to the outer peripheral side of the base. The opening of the water receiving tray is lower than the top surface of the base;

[0019] A drain pipe is connected to the inner bottom of the water receiving tray;

[0020] The lower sealing pressing block is installed on the top surface of the base of the frame, and support legs are arranged at the bottom of the base;

[0021] Both the lower sealing pressing block and the upper sealing pressing block are in the shape of a "convex" character. Sealing rings are arranged on the sealing end faces of the lower sealing pressing block and the upper sealing pressing block for abutting against the flange end face, and the air charging port is located on the lower sealing pressing block;

[0022] The upper sealing pressing block is installed on the bottom surface of the lifting seat body on the frame. The number of the spray heads is several and they are circumferentially and uniformly arranged on the bottom surface of the lifting seat body on the outer peripheral side of the upper sealing pressing block;

[0023] The diameter of the lifting cover cylinder is the same as that of the water receiving tray. A sealing ring is fixedly arranged on the lower barrel opening of the lifting cover cylinder for contact sealing with the open mouth of the water receiving tray when the lifting cover cylinder descends;

[0024] One outer peripheral side of the lifting cover cylinder is in sliding fit with a vertical sliding rail fixedly connected to the external frame through a slider, and the other outer peripheral side of the lifting cover cylinder is connected to a cylinder for controlling its lifting.

[0025] A light output end is arranged at the lifting seat body. The light output end includes an LED light source and a first Fresnel lens for converting light into parallel light output; a light receiving end is arranged at the base, and a second Fresnel lens for converging light to a detection point is arranged at the light receiving end.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention utilizes the interference of air bubbles at the leakage point to the detection optical path to form an automatically detectable optical feature, and strengthens the recognizability of the optical feature through a focusing device, so as to automatically determine whether there is leakage in the gas flowmeter by an electronic device, improving the detection efficiency.

[0028] In the present invention, low-intensity detection light or infrared light is adopted, and a component that can make the foam a dark (black) foam is added to the foam water component, which is beneficial to the foam acting on the detection light, thereby optimizing the sensitivity of the leak detection.

[0029] Since the present invention adopts Fresnel lenses in the optical path, the installation space can be effectively reduced, the optical path is convenient to debug, and it is also beneficial to the implementation and maintenance of the product.

[0030] The Fresnel lens for focusing adopted in the optical path of the present invention can design the focusing focus at a position deviating from the optical axis according to the specific structure of the device to avoid the device, which is beneficial to the customization of the device.

[0031] In the present invention, the lifting cover cylinder is default in a non-closed structure. When the lifting cover cylinder is used as a closed structure, air can be pumped out inside the lifting cover cylinder to form a pressure difference inside and outside the gas flowmeter for testing.

[0032] In the present invention, since the detection signal is formed by the interference of the bubbles on the outer wall of the gas flowmeter with the test light, there is no requirement for the shape of the gas flowmeter. It is only necessary that the foam on the outer wall of the flowmeter can escape normally during the test, thus greatly expanding the applicable range of the test device.

[0033] In the present invention, the liquid tension of the foam water can be adjusted by changing the component formula of the foam water, thereby changing the foaming effect on the outer wall of the flowmeter and adjusting the detection sensitivity.

[0034] The structure of the automatic leak detection device for the whole gas flowmeter is simple. When the gas flowmeter is sealed and ventilated for leak detection, the lifting cover cylinder can descend to surround the gas flowmeter inside, so as to prevent the foam water sprayed by the nozzle from splashing outside. At the same time, the water receiving tray is used to collect the foam water to prevent it from flowing to the ground. Brief Description of the Drawings

[0035] The following is a further detailed description of the present invention in conjunction with the drawings and specific embodiments:

[0036] Attached Figure 1 is a schematic diagram of the working state of the embodiment of the present invention Figure 1 ;

[0037] Attached Figure 2 is a schematic diagram of the working state of the embodiment of the present invention Figure 2 ;

[0038] Attached Figure 3 is a schematic diagram of the working state of the embodiment of the present invention Figure 3 ;

[0039] Attached Figure 4 is Figure 2 a schematic diagram of the partial structure of

[0040] Attached Figure 5 is a schematic diagram of the partial circuit of the light intensity detection circuit of the present invention;

[0041] Attached Figure 6 is a schematic diagram of the optical path principle of the automatic leak detection method of the present invention. Specific Embodiments

[0042] As shown in the figure, the working method of the automatic leak detection device for the whole gas flowmeter includes the following steps;

[0043] Step S1, place the gas flowmeter to be tested in a cylindrical light-absorbing cover, leave an optical path gap between the outer wall of the gas flowmeter and the light-absorbing cover, and coat the surface of the gas flowmeter with foam water;

[0044] Step S2: Set a light output end beside one end of the gas flowmeter, and set a light receiving end beside the other end. Input a low-brightness detection light from the light output end. The detection light is adjacent to and parallel to the outer wall of the light absorption cover to form an annular columnar detection light path. At the light receiving end, a light focusing device focuses the detection light on the detection point to form a light spot. The light intensity value of the light spot is detected by a light intensity detection circuit 103 at the detection point.

[0045] Step S3: Fill the gas flowmeter with gas. If there is a leakage point on the outer wall of the gas flowmeter, the gas will escape from the leakage point and form foam. The foam increases the light attenuation of the detection light path by refracting, reflecting, or absorbing the detection light. When the attenuation amplitude of the light intensity of the light spot detected by the light intensity detection circuit is greater than the threshold within a preset time period, it is determined that there is a leak on the outer wall of the gas flowmeter.

[0046] The light intensity detection circuit includes a single-chip microcomputer, a photosensitive resistor, and a triode connected thereto. The light-receiving surface of the photosensitive resistor is irradiated by the light spot at the detection point. The output voltage of the collector of the triode is input to the A / D converter of the single-chip microcomputer. The single-chip microcomputer evaluates the light intensity value of the light spot to determine whether there is a leakage point in the currently detected gas flowmeter.

[0047] An absorbing layer is provided on the inner wall of the light absorption cover. When the detection light is infrared light, the foam can absorb the infrared light.

[0048] The foam water is dark-colored foam water. In addition to the pigment component, its components also include the following: nonylphenol polyoxyethylene ether NP-10 30%, glycerol 10%, CMC 2%, brilliant blue 0.01%, and the balance is water.

[0049] The working method further includes step S4, the content of which is to open the light absorption cover. When there is a leakage point on the outer wall of the gas flowmeter and there is a large amount of foam at this point, use a ventilation device to blow away the foam at the gas flowmeter.

[0050] The ventilation device includes an air outlet device and an air suction device disposed on both sides of the light absorption cover. After the air outlet device blows down the foam at the gas flowmeter, the air suction device sucks in the blown-down foam to prevent pollution of the test environment.

[0051] Such as Figures 1 to 4As shown in the figure, this embodiment provides an automatic leak detection device for the whole gas flowmeter, including a frame 1. An upper sealing press block 4 for abutting against the upper flange 3 of the gas flowmeter 2 is arranged on the frame. A lower sealing press block 6 for abutting against the lower flange 5 of the gas flowmeter is arranged directly below the upper sealing press block. A water receiving tray 7 is arranged beside the outer periphery of the lower sealing press block. An elevating cover cylinder 8 for surrounding the gas flowmeter coaxially is arranged above the water receiving tray. A spray head 9 for spraying foam water towards the gas flowmeter is arranged inside the elevating cover cylinder. An air inlet 10 is arranged on the upper sealing press block or the lower sealing press block.

[0052] In the embodiment of the present invention, the frame includes a base 11. At least two vertical guide rods 12 are fixedly connected to the base. The guide rods all pass through the guide holes of a lifting seat body 13 arranged above the base. The lifting seat body is driven to lift by a hydraulic cylinder 14 installed on the frame. The lower sealing press block is installed on the top surface of the base, and the upper sealing press block is installed on the bottom surface of the lifting seat body.

[0053] In the embodiment of the present invention, the lower sealing press block is installed on the top surface of the base through a rotating shaft and is driven by a motor to rotate actively. The upper sealing press block is installed on the bottom surface of the lifting seat body through a rotating shaft and rotates passively.

[0054] In the embodiment of the present invention, the lower sealing press block is installed on the top surface of the base of the frame. The water receiving tray is an annular structure with an open top and is coaxially connected to the outer periphery of the base. The open top of the water receiving tray is lower than the top surface of the base.

[0055] In the embodiment of the present invention, a drain pipe 15 is connected to the inner bottom of the water receiving tray to drain the foam water received thereon.

[0056] In the embodiment of the present invention, the lower sealing press block is installed on the top surface of the base of the frame. Support legs 16 are arranged at the bottom of the base.

[0057] In the embodiment of the present invention, the shapes of the lower sealing press block and the upper sealing press block are both "convex" shaped. Sealing rings 17 are arranged on the sealing end faces of the lower sealing press block and the upper sealing press block for abutting against the flange end faces. The air inlet is located on the lower sealing press block. The small-diameter sections of the "convex" shapes of the lower sealing press block and the upper sealing press block are used to insert into the flange for internal positioning.

[0058] In the embodiment of the present invention, the upper sealing press block is installed on the bottom surface of the lifting seat body on the frame. The number of the spray heads is several and they are circumferentially and evenly distributed on the bottom surface of the lifting seat body on the outer periphery of the upper sealing press block.

[0059] In an embodiment of the present invention, the diameter of the lifting cover cylinder is the same as that of the water receiving tray. A sealing ring 17 is fixedly provided on the lower barrel opening of the lifting cover cylinder for sealing contact with the open mouth of the water receiving tray when the lifting cover cylinder descends.

[0060] In an embodiment of the present invention, one outer peripheral side of the lifting cover cylinder is slidably engaged with a vertical slide rail 19 fixedly connected to an external frame through a slider 18, and the other outer peripheral side of the lifting cover cylinder is connected to a cylinder 20 for controlling its lifting.

[0061] A light output end is provided at the lifting seat body. The light output end includes an LED light source 100 and a first Fresnel lens 101 for converting light into parallel output. A light receiving end is provided at the base. A second Fresnel lens 103 for converging light to a detection point is provided at the light receiving end.

[0062] The working principle of the whole machine automatic leak detection device for the gas flowmeter is as follows: When in use, 1. The lower flange of the gas flowmeter is placed on the lower sealing pressing block, and the lifting seat body descends to make the upper sealing pressing block press against the upper flange of the gas flowmeter. In this way, the upper and lower flanges are tightly pressed and sealed through the sealing ring on the sealing pressing block. Immediately afterwards, the lifting cover cylinder descends, and the lower barrel opening of the lifting cover cylinder abuts against the open mouth of the water receiving tray, surrounding the gas flowmeter inside. 2. Then the upper and lower sealing pressing blocks drive the gas flowmeter to rotate, and the inflation port ventilates the inside of the gas flowmeter. The inflation port is connected to the intake hose through a rotary joint to prevent the intake hose from winding as it rotates. At the same time, the spray head sprays foam water on the outer surface of the gas flowmeter. 3. Then stop spraying foam water and keep ventilating. If there are bubbles on the outer surface of the gas flowmeter, the bubbles will cause light attenuation in the detection light path. When the attenuation amplitude of the light intensity of the light spot detected by the light intensity detection circuit is greater than the threshold within a preset time period, it is determined that there is a leak in the outer wall of the gas flowmeter.

[0063] The lifting cover cylinder can descend to surround the gas flowmeter inside to prevent the foam water sprayed by the spray head from splashing outside. At the same time, the water receiving tray is used to collect the foam water to prevent it from flowing to the ground.

Claims

1. Working method of the automatic leak detection device for the whole gas flowmeter, characterized in that: The working method includes the following steps; Step S1: Place the gas flowmeter to be tested inside a cylindrical light-absorbing cover, leaving an optical path gap between the outer wall of the gas flowmeter and the light-absorbing cover, and coat the surface of the gas flowmeter with foamed water; Step S2: Set a light output end beside one end of the gas flowmeter and a light receiving end beside the other end. Input a low-brightness detection light from the light output end. The detection light is adjacent to the outer wall of the light-absorbing cover and forms an annular columnar detection optical path parallel to the outer wall of the light-absorbing cover. At the light receiving end, a light focusing device focuses the detection light at the detection point to form a light spot. The light intensity value of the light spot is detected by a light intensity detection circuit at the detection point; Step S3: Fill the gas flowmeter with gas. If there is a leakage point on the outer wall of the gas flowmeter, the gas will escape from the leakage point and form foam. The foam increases the light attenuation of the detection optical path by refracting the detection light, reflecting the detection light, or absorbing the detection light. When the attenuation amplitude of the light intensity of the light spot detected by the light intensity detection circuit is greater than the threshold within a preset time period, it is determined that there is a leak on the outer wall of the gas flowmeter; An automatic leak detection device for the whole gas flowmeter includes a frame. On the frame, there is an upper sealing press block for abutting against the upper flange of the gas flowmeter. Directly below the upper sealing press block, there is a lower sealing press block for abutting against the lower flange of the gas flowmeter. A water receiving tray is arranged beside the outer periphery of the lower sealing press block. Above the water receiving tray, a lifting cover cylinder for surrounding the gas flowmeter coaxially is arranged. Inside the lifting cover cylinder, there is a spray head for spraying foamed water towards the gas flowmeter. An air inlet is arranged on the upper sealing press block or the lower sealing press block. The lifting cover cylinder is a light-absorbing cover.

2. The working method of the automatic leak detection device for the whole gas flowmeter according to claim 1, characterized in that: The light intensity detection circuit includes a single-chip microcomputer, a photosensitive resistor, and a triode connected thereto. The light-receiving surface of the photosensitive resistor is irradiated by the light spot at the detection point. The output voltage of the collector of the triode is input to the A / D converter of the single-chip microcomputer. The single-chip microcomputer evaluates the light intensity value of the light spot to judge whether there is a leakage point in the currently detected gas flowmeter.

3. The working method of the automatic leak detection device for the whole gas flowmeter according to claim 1, characterized in that: An absorbent layer is provided on the inner wall of the light-absorbing cover. When the detection light is infrared light, the foam can absorb infrared light.

4. The working method of the automatic leak detection device for the whole gas flowmeter according to claim 1, characterized in that: The foamed water is dark-colored foamed water. In addition to the pigment component, its components also include the following: nonylphenol polyoxyethylene ether NP-10 30%, glycerol 10%, CMC 2%, brilliant blue 0.01%, and the balance is water.

5. The working method of the automatic leak detection device for the whole gas flowmeter according to claim 1, characterized in that: The working method further includes step S4, the content of which is to open the light-absorbing cover. When there is a leakage point on the outer wall of the gas flowmeter and there is a large amount of foam at this point, use a ventilation device to blow away the foam at the gas flowmeter.

6. The working method of the automatic leak detection device for the whole gas flowmeter according to claim 5, characterized in that: The ventilation device includes an air outlet device and an air suction device separately arranged on both sides of the light-absorbing cover. After the air outlet device blows down the foam at the gas flowmeter, the air suction device sucks in the blown-down foam to prevent pollution of the test environment.

7. The working method of the automatic leak detection device for the whole gas flowmeter according to claim 1, characterized in that: The frame includes a base. At least two vertical guide rods are fixedly connected to the base. The guide rods all pass through the guide holes of a lifting seat body arranged above the base. The lifting seat body is driven to lift by a hydraulic cylinder installed on the frame. The lower sealing press block is installed on the top surface of the base, and the upper sealing press block is installed on the bottom surface of the lifting seat body; The lower sealing pressing block is installed on the top surface of the base through a rotating shaft and is driven by a motor to rotate actively, and the upper sealing pressing block is installed on the bottom surface of the lifting seat body through a rotating shaft to rotate passively.

8. The working method of the automatic leak detection device for the whole gas flowmeter according to claim 1, characterized in that: The lower sealing pressing block is installed on the top surface of the base of the frame. The water receiving tray is an annular structure with an upward-facing opening and is coaxially connected to the outer peripheral side of the base. The opening of the water receiving tray is lower than the top surface of the base. A drain pipe is connected to the inner bottom of the water receiving tray. The lower sealing pressing block is installed on the top surface of the base of the frame, and support legs are provided at the bottom of the base. The shapes of the lower sealing pressing block and the upper sealing pressing block are both "convex" shaped. Sealing rings are provided on the sealing end faces of the lower sealing pressing block and the upper sealing pressing block for abutting against the flange end face, and the air inlet is located on the lower sealing pressing block. The upper sealing pressing block is installed on the bottom surface of the lifting seat body on the frame. The number of the nozzles is several and they are circumferentially and evenly distributed on the bottom surface of the lifting seat body on the outer peripheral side of the upper sealing pressing block. The diameter of the lifting cover cylinder is the same as that of the water receiving tray. A sealing ring is fixedly provided on the lower barrel opening of the lifting cover cylinder for sealing contact with the opening of the water receiving tray when the lifting cover cylinder descends. One outer peripheral side of the lifting cover cylinder is slidably matched with a vertical slide rail fixedly connected to the external frame through a slider, and the other outer peripheral side of the lifting cover cylinder is connected to a cylinder for controlling its lifting.

9. The working method of the automatic leak detection device for the whole gas flowmeter according to claim 7, characterized in that: A light output end is provided at the lifting seat body. The light output end includes an LED light source and a first Fresnel lens for converting the light into parallel light output. A light receiving end is provided at the base. A second Fresnel lens for converging the light to the detection point is provided at the light receiving end.

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