WO2020215540A1

WO2020215540A1 - Static seal leakage detection device

Info

Publication number: WO2020215540A1
Application number: PCT/CN2019/101728
Authority: WO
Inventors: 郭飞; 温天政; 黄毅杰; 项冲; 贾晓红; 王玉明
Original assignee: 清华大学
Priority date: 2019-04-20
Filing date: 2019-08-21
Publication date: 2020-10-29
Also published as: CN110006596B; CN110006596A

Abstract

A static seal leakage detection device, which represents the leakage of a sealing strip using an electrical signal. The sealing strip is disposed between an upper cover (1) and a box body (7). A sensor group (8) composed of several sensors is disposed in the contact region of the sealing strip on the upper end surface of the box body (7). Each sensor comprises a positive plate and a negative plate separated by an insulating sheet, wherein each positive plate is connected to the positive electrode of an external power supply, and each negative plate is connected to the negative electrode of the external power supply. In a normal state without leakage, the entire circuit is open; when a leakage occurs, a conductive liquid medium covers the insulating sheet, and the positive plate is connected to the negative plate. The static seal leakage detection device implements sensitive detection and is easy to operate.

Description

Static seal leak detection device

Technical field

The invention belongs to the technical field of static seal leakage detection, and particularly relates to a static seal leakage detection device, which is suitable for potential leakage risk assessment and leakage detection of a sealing strip under a conductive liquid medium.

Background technique

Static seal refers to a type of seal in which the sealing interface does not slide relatively, and the joint surface is relatively static. Sealing parts are usually installed between the sealing end faces. The sealing parts are soft in texture, have good resilience and followability, and can fill the tiny gaps on the sealed end faces to achieve the sealing effect. However, due to the influence of assembly errors, material mechanical properties, external working conditions and other factors, the sealing system may leak the sealing medium. Leakage affects the normal operation of machinery and equipment. Detecting the sealing performance and leakage of seals in advance, assessing the risk of seal leakage, can effectively avoid mechanical equipment failures, economic losses, and casualties.

There are many leak detection methods. For gas media, atmospheric pressure detection is generally used. Gas leakage causes the pressure in the sealed cavity to decrease. A pressure gauge is installed to detect the pressure change in the sealed cavity. For liquid media, leak detection can be achieved by observing liquid leakage and connecting external collection devices. As for the air pressure detection method, in addition to the leakage of the sealing interface, there may be gas leakage at the gas inlet, the pressure gauge interface, etc., which reduces the pressure indication and leads to inaccurate detection. For liquid leakage detection, the viscosity of the liquid itself is higher than that of gas, especially for static seals, the leakage is small, the leaked liquid is not easy to observe directly, and it is difficult to collect the leaked liquid. This brings certain difficulties to liquid medium leakage detection.

Summary of the invention

In order to overcome the above shortcomings of the prior art, the purpose of the present invention is to provide a static seal leakage detection device, which can detect the static seal leakage and accurately locate it.

In order to achieve the above objective, the technical solution adopted by the present invention is:

A static seal leakage detection device. The sealing strip is arranged between the upper cover 1 and the box body 7, and is characterized in that a sensor group 8 composed of several sensors is arranged on the upper end surface of the box body 7 in the sealing strip contact area. A sensor includes a positive plate and a negative plate separated by an insulating thin plate. Each positive plate is connected to the positive electrode of the external power supply, and each negative plate is connected to the negative electrode of the external power supply. Under normal no leakage state, the entire circuit is open. When leakage occurs , The conductive liquid medium is covered above the insulating sheet, and the positive plate and the negative plate are connected.

A negative electrode metal strip 10 and a positive electrode metal strip 11 are arranged on the upper edge of the box body 7. Each positive electrode plate is connected to the positive electrode of the external power supply through the positive electrode metal strip 11, and each negative electrode plate is connected to the negative electrode of the external power supply through the negative electrode metal strip 10. A light-emitting diode 6 is connected between each positive plate and the positive metal strip 11, or between each negative plate and the negative metal strip 10, and between the positive metal strip 11 and the positive electrode of the external power supply, or the negative metal strip 10 An ammeter is connected to the negative pole of the external power supply.

The cross section of the box body 7 is square, and the sensors are arranged on the three boundaries of the upper end surface of the box body 7. The positive electrode metal strip 11 and the negative electrode metal strip 10 are also arranged on the three boundaries. The negative electrode metal strip 10 and the positive electrode The metal bars 11 are located at different heights.

The three boundaries of the box body 7 are provided with a negative metal strip card slot 24 and a positive metal strip card slot 15, each of which is provided with three metal strip fixing positions 12, and the sealing strip contact area is distributed on the three borders. Set the sensor slot 13, and the length of the adjacent sensor slot 13 decreases linearly, so that the measurement position is distributed in the contact area of the sealing strip. The contact area of the sealing strip of the sensorless slot 13 is provided with an anti-overload protrusion 14. Symmetrical distribution, used to locate the sealing strip to prevent reverse installation.

Each group of the sensor slot 13 is composed of groove one and groove two, groove one and groove two have the same length, and are used to place the positive electrode plate and the negative electrode plate, respectively. The interval is 0.5mm,

The box body 7 is provided with a right-angled U-shaped clamp 5 along the outer side, which is clamped on the three boundaries, and the box body 7 is provided with a horizontal slide along the three boundary directions along the outer side. Rail 17, wherein the upper part of the holder 5 is matched with the upper surface of the box body 7, and the negative metal strip 10 is sandwiched therebetween. The lower part is provided with a groove 22 that matches the slide rail 17, and the positive metal strip 11 is clamped in the groove 22 Between the slide rail 17 and the holder 5, the middle part of the holder 5 is hollowed out, and the light-emitting diodes 6 are located in the hollowed out position to facilitate the observation of light emission.

The four corners of the upper cover 1 are provided with through holes 19, the periphery of the through hole 19 is provided with a groove for placing the gasket 2, a limit block 4 is provided above the sealing strip, and the four corners of the box body 7 are provided with threaded holes 21, bolts 3 Pass through the through hole 19, the gasket 2, the stop block 4 and the threaded hole 21, and connect with the box body 7. The upper cover 1, the box body 7, the holder 5, and the stop block 4 are all insulating materials.

The contact area of the sealing strip is lengthened, and the four corners of the contact area are provided with two overload prevention protrusions 20. When an overload occurs, the second overload prevention protrusion 20 contacts the surface of the box body 7 to prevent the sensor from being directly carried.

Compared with the prior art, the beneficial effects of the present invention are:

The device detects the leakage of the sealed interface, which can avoid the influence of leakage at other locations.

This device can detect the infiltration of liquid medium at different positions on the sealing contact surface. The device can measure liquid leakage. In the case of no leakage in the sealing strip, the sensor can detect the presence of liquid medium in the sealing area, which can assess potential leakage risk.

By replacing the limit block, different loads can be loaded to perform a leak test on the sealing strip.

The electrical signal can more sensitively detect the presence of the liquid medium at the contact position of the sealing strip.

Description of the drawings

Fig. 1 is a schematic diagram (a perspective view) of the structure of the present invention.

Figure 2 is a schematic diagram (longitudinal cross-sectional view) of the present invention.

Figure 3 is a longitudinal sectional view of the box of the present invention.

Figure 4 is a top view of the box of the present invention.

Fig. 5 is a schematic diagram (a perspective view) of the structure of the holder of the present invention.

Figure 6 is a bottom view of the upper cover of the present invention.

Figure 7 is a side view of the upper cover of the present invention.

Figure 8 is a perspective view of the upper cover of the present invention.

Detailed ways

In order to make the working principle and structural features of the leak detection device easy to understand, the device will be further explained below in conjunction with the drawings and specific implementations.

1 and 2, a static seal leakage detection device of the present invention includes an upper cover 1 and a box body 7. The box body 7 has a square cross section and a sealing strip is arranged between the upper cover 1 and the box body 7.

A sensor group 8 composed of several sensors is arranged on the upper end surface of the box 7 in the sealing strip contact area. Each sensor includes a positive plate and a negative plate separated by an insulating sheet. The thinner the insulating sheet, the higher the sensitivity of the sensor. . Among them, each positive plate is connected to the positive pole of the external power supply, and each negative plate is connected to the negative pole of the external power supply. Under normal no leakage, the entire circuit is open. When leakage occurs, the conductive liquid medium covers the insulating sheet, the positive plate and the negative plate. Conduction.

Among them, each positive plate is connected to the positive electrode of the external power supply through the positive metal strip 11, and each negative plate is connected to the negative electrode of the external power supply through the negative metal strip 10, wherein each positive plate and the positive metal strip 11, or each negative plate and the negative electrode A light-emitting diode 6 is connected between the metal strips 10, and an ammeter is connected between the positive metal strip 11 and the positive pole of the external power supply, or between the negative metal strip 10 and the negative pole of the external power supply. When the positive plate and the negative plate are connected When the corresponding light-emitting diode 6 works, the ammeter on the bus line shows a number.

That is, the sensor is used to detect leakage, the positive/negative metal strip is responsible for transmitting the electrical signal obtained by the sensor, the ammeter is used to indicate the current change on the bus line, and the light-emitting diode indicates the location of the leakage.

Specifically, referring to FIG. 3 and FIG. 4, the box body 7 is a carrier of the sensor, the sealing strip, the holder, and the metal strip, and the box body 7 is provided with a liquid inlet 9. A sealing strip placement slot 18 with a width of 20 mm and a depth of 6 mm is provided on the upper end of the box body 7 for positioning and placing the sealing strip. The upper end surface of the box body 7 is provided with threaded holes 21 at four corners for mating connection with the upper cover 1.

The three boundaries of the box body 7 are provided with a negative metal strip card slot 24 and a positive metal strip card slot 15, and a horizontal slide rail 17 is provided on the outer edge of the three borders. The slide rail 17 is 40mm from the upper boundary, and each side protrudes 20mm outward. The box 7 is provided with a right-angled U-shaped holder 5 along the outside, which is clamped on the three boundaries, and the slide rail 17 is used to cooperate with the holder 5.

The negative metal strip card slot 24 is parallel to the positive metal strip card slot 15, the positive metal strip card slot 15 is located above the slide rail 17, and each boundary is provided with three 8mm*2mm metal strip fixing positions 12, and the negative metal strip card slot 24 The negative metal strip 10 is installed in the metal strip fixing position 12 of the metal strip, and the positive metal strip 11 is installed in the metal strip fixing position 12 of the positive metal strip card slot 15. There are 30 sets of sensor card slots 13 distributed on the three boundaries in the sealing strip contact area. Measure the leakage of 30 different locations in the contact area of the sealing strip, that is, the position where the conductive liquid penetrates into the interface on the contact surface of the sealing strip, and evaluate the leakage risk. In order to detect leakage at different locations in the contact area of the sealing strip, the lengths of the adjacent sensor slots 13 are linearly decreased in sequence (with a difference of 0.5 mm in sequence), so that the measurement positions are distributed throughout the contact area of the sealing strip. Each sensor slot 13 is composed of groove one and groove two. The length of groove one and groove two are equal, and they are used to place the positive plate and negative plate of a sensor respectively. The interval between groove one and groove two is 0.5 mm.

On the outside of the three borders of the box body 7, there is also a light-emitting diode mounting groove 16 for mounting light-emitting diodes. The contact area of the sealing strip of the sensorless card groove 13 is provided with an overload prevention protrusion 14 with a radius of 4mm and a height of 0.5mm. Symmetrical distribution, used to locate the sealing strip, prevent reverse installation, and cooperate with the upper cover 1 to prevent damage to the sensor when the load is too large.

Referring to FIG. 5, the holder 5 is connected to the box body 7 through the groove 22 and the bolt 23, and is used to fix the sensor group 8, the metal bar and the circuit, and prevent external contaminants from entering the sensor and the box body. The upper part is matched with the upper surface of the box body 7, and the negative metal strip 10 is sandwiched therebetween. The lower part is provided with a groove 22 that is matched with the slide rail 17. The positive metal strip 11 is sandwiched between the groove 22 and the slide rail 17. The middle part of the holder 5 is hollowed out, and each light-emitting diode 6 is located at the hollowed out position to facilitate the observation of the light emission. The terminals of the positive and negative plates are located on the holder 5 and are used to connect in series with the ammeter and the external power supply.

6, 7 and 8, the upper cover 1 is a cavity structure used to form a complete sealed cavity with the box 7 and fix the sealing strip, and cooperate with the box 7 to apply a load to the sealing strip. The four corners are provided with through holes 19, the periphery of the through hole 19 is provided with a groove for placing the gasket 2, and a limit block 4 is arranged above the sealing strip. The bolt 3 passes through the through hole 19, the gasket 2, the limit block 4 and the thread The hole 21 is connected with the box body 7, and the limit block 4 is used for a given compression amount. The sealing strip contact area is lengthened to facilitate observation of the loading and leakage of the sealing strip, and to prevent the lower surface of the upper cover 1 from contacting the holder 5 or the upper part of the box body 7. And the four corners of the contact area are provided with two anti-overload protrusions 20 with a radius of 4mm and a height of 0.5mm, which are matched with the overload prevention protrusion 14 on the box body. When an overload occurs, the second overload prevention protrusion 20 contacts the surface of the box body 7. , To avoid the direct bearing of the sensor. When the compression amount exceeds the preset value, the sealing contact area on the upper cover 1 contacts the overload prevention protrusion 20, and the action stops to prevent excessive load and damage to the sensor and other structures of the box.

Considering the need to create an insulating environment during the operation of the leak detection device to eliminate external electromagnetic interference and the influence of its own current, the upper cover 1, the box 7, the holder 5, and the limit block 4 are made of insulating materials.

The working principle of the leakage detection device of the present invention is as follows: the positive and negative electrodes of the external power supply are respectively connected with the positive and negative metal strips, and an ammeter is connected in series on the positive line. The sensors are connected in parallel, and a light-emitting diode is installed on the positive circuit of each sensor. The positive and negative plates are separated by a thin insulating material. In a normal state without leakage, the entire circuit is in an open state, and the ammeter has no indication. When the sealing device leaks, when the conductive liquid flows over the surface of the insulating material, the positive and negative plates are turned on, and a current is formed under the action of the external voltage. The light-emitting diode works, and the ammeter produces an indicator to characterize the leakage of the conductive liquid. . 30 sets of sensors are installed at different positions in the contact area of the sealing strip, which can measure the leakage of conductive liquid at different penetration depths. Of course, if the entire circuit is conductive, the conductive liquid will leak out of the box.

The sealing strip test samples used are prepared according to the size and structural shape of the sealing strip slot of the box body and the upper cover. The size is slightly smaller than the card slot, and the position of the limit hole is consistent with the upper cover anti-overload protrusion and the box body anti-overload protrusion.

Leaking device operation steps:

1. Connect the circuit, apply conductive liquid on the surface of each sensor, and observe whether the light-emitting diode and ammeter work normally and whether the circuit is normal.

2. Disconnect the circuit, remove the conductive liquid on the surface of the sensor, and place the sealing strip sample in the sealing strip slot of the box.

3. Select the limit block according to the predetermined compression amount.

4. Assemble the upper cover, bolts, gaskets, box body, and holder in sequence.

5. Use a pressure pump to inject the conductive liquid into the tank through the water inlet and keep the pressure constant.

6. Turn on the power and start testing.

In order to improve the detection accuracy, the thickness of the insulating sheet between the positive and negative plates can be appropriately reduced, and the voltage between the two plates can be increased.

Claims

A static seal leakage detection device, the sealing strip is arranged between the upper cover (1) and the box body (7), and is characterized in that a plurality of sensors are arranged on the upper end surface of the box body (7) in the sealing strip contact area Each sensor includes a positive plate and a negative plate separated by an insulating sheet, wherein each positive plate is connected to the positive pole of the external power supply, and each negative plate is connected to the negative pole of the external power supply. The entire circuit is in a normal, non-leakage state It is in a disconnected state. When leakage occurs, the conductive liquid medium covers the insulating sheet, and the positive plate and the negative plate are connected.
The static seal leakage detection device according to claim 1, wherein the upper edge of the box (7) is provided with a negative metal strip (10) and a positive metal strip (11), wherein each positive plate passes through the positive metal strip ( 11) Connect the positive pole of the external power supply, each negative plate is connected to the negative pole of the external power supply through the negative metal strip (10), between each positive plate and the positive metal strip (11), or each negative plate and the negative metal strip (10) A light emitting diode (6) is connected between ), and an ammeter is connected between the positive metal strip (11) and the positive pole of the external power supply, or between the negative metal strip (10) and the negative pole of the external power supply.
The static seal leakage detection device according to claim 2, characterized in that the box body (7) has a square cross-section, and each sensor is arranged on three boundaries on the upper end surface of the box body (7), and the positive metal strip ( 11) and the negative electrode metal strip (10) are also arranged on the three boundaries, and the negative electrode metal strip (10) and the positive electrode metal strip (11) are located at different heights.
The static seal leakage detection device according to claim 3, characterized in that the three boundaries of the box (7) are provided with a negative metal strip slot (24) and a positive metal strip slot (15), and each boundary There are 3 metal strip fixing positions (12) on the top. There are multiple sets of sensor slot (13) distributed on the three boundaries in the contact area of the sealing strip. The length of the adjacent sensor slot (13) decreases linearly, so that the measurement position is distributed In the entire sealing strip contact area, there are anti-overload protrusions (14) arranged asymmetrically in the sealing strip contact area of the sensorless card slot (13), which are used to locate the sealing strip and prevent reverse installation.
The static seal leakage detection device according to claim 4, characterized in that, each group of said sensor slot (13) is composed of groove one and groove two, and groove one and groove two are equal in length and are used for placing The positive electrode plate and the negative electrode plate are separated by 0.5 mm between groove one and groove two,
The static seal leakage detection device according to claim 3, characterized in that a right-angle U-shaped clamp (5) is provided along the outside of the box (7), clamped on the three boundaries, The box (7) is provided with horizontal slide rails (17) along the three boundary directions along the outer side, and the upper part of the holder (5) is matched with the upper surface of the box (7), and the There is a negative metal strip (10), the lower part is provided with a groove (22) that matches with the slide rail (17), the positive metal strip (11) is sandwiched between the groove (22) and the slide rail (17), and the holder The middle part of (5) is hollowed out, and each light-emitting diode (6) is located at the hollowed out position to facilitate observation of the light-emitting condition.
The static seal leakage detection device according to claim 1, characterized in that the four corners of the upper cover (1) are provided with through holes (19), and the periphery of the through hole (19) is provided with a groove for placing a gasket (2) , A limit block (4) is set above the sealing strip, four corners of the box body (7) are provided with threaded holes (21), and the bolt (3) passes through the through hole (19), the gasket (2), and the limit block (4) The threaded hole (21) is connected with the box body (7), and the upper cover (1), the box body (7), the holder (5) and the limit block (4) are all insulating materials.
The static seal leak detection device according to claim 1, characterized in that the contact area of the sealing strip is lengthened, and four corners of the contact area are provided with anti-overload protrusions (20) to prevent overload when an overload occurs. The overload protrusion (20) is in contact with the surface of the box body (7) to prevent the sensor from being directly carried.