JP2002107258A - Artificial leak device for air leak tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an artificial leak device capable of providing the relation between atmospheric pressure-converted leak quantity and change of detected pressure without determining a work capacity in an air leak tester and precisely and easily changing the leak quantity. SOLUTION: This artificial leak device is to be connected to the air passage of the air leak tester together with a pressure sensor. This device comprises a decompression part A for reducing the test pressure from the air passage and a flow detection part B connected between the decompression part A and the atmospheric side. The decompression part A comprises a body 10 having an artificial leak passage 12a, an elastically deformable pressure reducing element 11 formed of a porous foamed resin arranged in the artificial leak passage 12a, a pressing member 23 for pressing and compressing the pressure reducing element, and an adjusting mechanism 30. The adjusting mechanism 30 adjusts the position of the pressing member 23 to adjust the compression degree of the pressure reducing element 22, and also regulates the flow rate of the air passing in the flow detection part B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pseudo leak device used for an air leak tester.

[0002]

2. Description of the Related Art A conventional air leak tester, for example, a differential pressure type air leak tester has an air passage including a master-side branch passage and a work-side branch passage, and is closed in a state where a test pressure is applied to these branch passages. In this closed state, the differential pressure between the two branch passages is detected by a differential pressure sensor. If there is no leak in the work connected to the work side branch air passage, the differential pressure is zero, but if there is a leak in the work, a differential pressure corresponding to the magnitude of the leak is detected.

[0003] Recently, it has been required to detect the magnitude of the leakage of the workpiece not by the differential pressure but by the leakage amount in terms of atmospheric pressure. The atmospheric pressure equivalent leakage cannot be calculated only from the above detected differential pressure. The detected differential pressure is calculated by multiplying the volume of the closed branch passage (the volume obtained by subtracting the external volume of the workpiece and master) and the test pressure. And is calculated. For this reason, the volume of the branch passage is determined in advance. For example, when one branch passage is closed and the other branch passage is opened to the atmosphere, a detected differential pressure is obtained.Also, with both branch passages closed, the air in one branch passage is discharged to a predetermined volume. A pseudo leak is caused in the tank, and the detected differential pressure at this time is obtained. Then, the volume of the branch passage is obtained from these detected differential pressures.

[0004] In order to avoid the above-mentioned complicated volume calculation, a device for pseudo-leakage of a constant flow rate has been developed. This simulated leak device has a thin tube. The flow rate is determined from the length and inner diameter of the capillary and the test pressure. Both branch passages are closed, a pseudo-leakage device having a constant flow rate is caused by a pseudo-leakage device connected to one branch passage, and a change in the detected differential pressure over a predetermined time width is measured. , It is possible to know the direct relationship between the change in the detected differential pressure and the amount of leakage in terms of the atmospheric pressure. Specifically, the proportional constant can be known. Thereafter, an air leak test is performed, and the detected differential pressure change amount is multiplied by a proportional constant to obtain an atmospheric pressure equivalent leak amount of the work.

[0005]

However, the above apparatus has the following disadvantages. That is, when checking whether or not the leak amount and the change in the detected differential pressure are in a linear relationship, it is necessary to see the change in the detected differential pressure for different flow rates. It had to be used, and the replacement work was complicated. Also, in order to determine the proportionality constant more accurately, when the change in the detected differential pressure is observed at a plurality of flow rates, it is necessary to replace the thin tube in the same manner.

Further, since one end of the above-mentioned thin tube is at a test pressure and the other end is at atmospheric pressure, a very thin thin tube is required, and there is a drawback that the tube is easily clogged. Moreover, if a pseudo leak is performed in a state where the thin tube is clogged, a change in the detected differential pressure will be seen in a state where the intended flow rate cannot be achieved.
In some cases, the determined proportionality constant was incorrect.

[0007]

SUMMARY OF THE INVENTION The present invention provides a pseudo-leakage device connected to an air passage of an air leak tester together with a pressure sensor, a pressure reducing portion for reducing a test pressure from the air passage, and a pressure reducing portion and the atmosphere side. And a flow detecting unit connected between the pressure reducing unit and the pressure reducing unit, a body having a pseudo leak passage, an elastically deformable pressure reducing element having a large number of minute passages disposed in the pseudo leak passage, A pressure member for pressing and compressing the pressure reducing element, and adjusting means for adjusting the degree of compression of the pressure reducing element by adjusting the position of the pressure member, and thereby adjusting the flow rate of air passing through the flow rate detecting unit. It is characterized by the following.

According to the pseudo leak device having the above-described structure, when the pseudo leak device is connected to the air leak tester to generate a pseudo leak, the flow rate is detected by the flow rate detecting section, so that the detected flow rate and the pressure detected by the pressure sensor of the air leak tester are detected. Based on the change, a direct relationship between the atmospheric pressure equivalent leakage amount and the change in the detected pressure can be obtained. Also, a pseudo leak of a different flow rate can be generated only by changing the compression degree of the pressure reducing element by the adjusting means without replacing the components. In addition, the pressure reducing element has a large number of minute passages, and the flow resistance in the minute passages can be changed according to the degree of compression, so that the flow rate can be finely adjusted.

Preferably, the pressure reducing element is made of a continuous porous foamed resin. Thereby, a pressure reducing element can be obtained at low cost. Preferably, in the pseudo leak passage,
A receiving portion having a hole is provided, and the pressure reducing element is disposed between the receiving portion and the pressing member. Thus, the degree of compression can be adjusted in a stable state of the pressure reducing element.

[0010] Preferably, the pressing member has a pin portion which penetrates the pressure reducing element and is inserted into a hole of the receiving portion,
The gap between the outer periphery of the pin portion and the inner periphery of the hole serves as an air passage. Thereby, the position of the pressing member can be stably adjusted.

Preferably, a case having an opening at one end and a bottom wall at the other end is disposed in the pseudo leak passage, and the bottom wall is provided as the receiving portion, and the pressure reducing element and the pressing member are provided in the case. And the return spring are housed to constitute a unitized decompression cartridge,
A pressure reducing element is sandwiched between the pressing member and the bottom wall, the pressing member is urged in a direction away from the pressure reducing element by a return spring, and movement in the same direction is regulated by a stopper provided in the case. I have. According to this,
Since the depressurizing element and the pressing element are pre-installed as a cartridge, they can be easily installed and replaced.

Preferably, the adjusting means is screwed into the body of the pressure reducing section and is hermetically inserted into the pseudo leak passage, and a pressing member interposed between the pressing member and the operating member. , A first spring disposed between the intermediate member and the operating member to urge the intermediate member toward the pressure reducing element, and a second spring for biasing the intermediate member away from the pressure reducing element. And a spring constant of the first spring is smaller than a spring constant of the second spring. Accordingly, the moving amount of the pressing member can be made smaller than the moving amount of the operating member, and the compression degree of the pressure reducing element, that is, the flow rate of the pseudo leak can be further finely adjusted.

[0013] Preferably, the adjusting means is screwed into the body of the decompression section and is hermetically inserted into the pseudo leak passage, and a pressing member interposed between the pressing members. And a return spring interposed between the pressing member and the receiving portion to urge the pressing member in a direction away from the pressure reducing element, and a spring of the pressing spring The constant is smaller than the spring constant of the return spring. Accordingly, the moving amount of the pressing member can be made smaller than the moving amount of the operating member, and the compression degree of the pressure reducing element, that is, the flow rate of the pseudo leak can be further finely adjusted. In addition, since a return spring for returning the pressing element is also used as a spring against the pressing spring, the number of components can be reduced.

Preferably, the flow detecting section includes a body having another pseudo leak passage, a thin tube, and another pressure sensor, and the other pseudo leak passage includes the pseudo leak passage of the pressure reducing section and the pressure reducing section. The narrow tube is disposed between the other pseudo leak passage and the atmosphere, and the other pressure sensor detects the pressure of the other pseudo leak passage. According to this, the configuration of the flow detection unit can be simplified.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an air leak tester according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the differential pressure type air leak tester has an air passage 1. The air passage 1 includes a shared passage 1x and a branch passage 1 branched from the shared passage 1x.
a and 1b. A test pressure source 2 including a compressed air source 2a and a regulator 2b is provided in the shared passage 1x. Further, a test pressure source 2 is provided in the shared passage 1x.
The electromagnetic three-way valve 3 is provided on the downstream side of. The electromagnetic three-way valve 3 has an atmosphere release position where the downstream side is connected to the atmosphere,
A test pressure application position where the upstream side and the downstream side are connected is selected. When off, it is in the open-to-atmosphere position.

The branch passages 1a and 1b are provided with normally open electromagnetic two-way valves 4a and 4b, respectively.
b are provided respectively. A differential pressure sensor 6 (pressure sensor) is connected between the branch passages 1a and 1b. The differential pressure sensor 6 can detect a differential pressure on the downstream side of the electromagnetic two-way valves 4a and 4b.

The differential pressure detected by the differential pressure sensor 7 is sent to the controller 7, and at the time of an air leak test, the controller 7 converts the detected differential pressure into an atmospheric pressure equivalent leak amount and displays it on the display unit 8. Further, a pseudo leak device 9 which is a feature of the present invention is connected to the branch passage 1a.

As shown in FIGS. 2 and 3, the pseudo leak device 9 includes a pressure reducing section A and a flow rate detecting section B. The pressure reducing section A has a body 10. This body 10
A cylinder 11 and a cylinder 12 which are arranged on the straight line so as to face each other;
It comprises a connecting member 13 connecting these tubes 11 and 12. As shown in FIG. 2, one end of the cylinder 11 has a connection port 11x connected to a branch passage 1a via a pipe (not shown).
And a passage 11a (a pseudo leak passage) connected to the connection port 11x. A filter 14 is provided in the passage 11a.
Is provided. The cylinder 11 has a stop valve 1
5 are provided to open and close the passage 11a.

The internal space of the cylinder 12 is a passage 12a (pseudo leakage passage). In the cylinder 12, a unitized decompression cartridge 2 is provided at an end opposite to the cylinder 11.
0 is hermetically inserted. The decompression cartridge 20
As shown best in FIG. 4, the case 21 includes a pressure reducing element 22, a pressing member 23, and a return spring 24 housed in the case 21. The case 21 has a cylindrical peripheral wall 21a and a bottom wall 21b (receiving portion).

The pressure reducing element 22 is formed in a disk shape by a foamed resin, is continuously porous (having a large number of minute passages), and is elastically deformable. In the present embodiment, it is obtained by compression molding urethane foam. Pressure reducing element 22
Is disposed between the bottom wall 21b of the case 21 and the pressing member 23, and is compressed when pressed by the pressing member 23 to reduce the thickness T (see FIG. 4) and increase the flow resistance as described later. It has become.

The pressing member 23 has a T-shaped passage 23a, and is urged by a return spring 24 housed in the case 21 in a direction away from the pressure reducing element 22, that is, toward the open end of the case 24. I have. A stopper 25 made of a C-ring is attached to the inner periphery near the opening end of the case 21, and locks the pressing member 23 to prevent the case 21 from falling off.

As shown in FIG. 4, a hole 21c is formed in the center of the bottom wall 21b of the case 24.
A pin portion 23b protruding from the pressing member 23 and penetrating the pressure reducing element 22 is inserted into 1c, thereby ensuring a stable posture of the pressing member 23. The diameter D1 of the pin portion 23b is smaller than the diameter D2 of the hole 21c, and a passage 26 is formed between the two.

As shown in FIG. 2 and FIG.
Further comprises an adjustment mechanism 30 (adjustment means) for adjusting the position of the pressing member 23 to adjust the degree of compression of the pressure reducing element 22. The adjustment mechanism 30 includes an operation rod 31 (operation member), an intermediate rod 32 (intermediate member), a first spring 33, and a second spring.

One end of the operating rod 31 is hermetically screwed into the cylinder 11, and the other end is hermetically inserted into the cylinder 12. A passage 31a extending in the axial direction is formed in the operation rod 31, and this passage 31a is formed by the passage 11a of the cylinder 11 and the cylinder 1
And the second passage 12a. A knob 35 is attached to the outer periphery of the operating rod 31. By turning the operating rod 31 through the knob 35, the operating rod 31 moves forward and backward with respect to the cylinder 12.

As best shown in FIG. 3, the intermediate rod 32 is slidably supported by a support 36 having a flanged cylindrical shape. The support 36 is fixed to the cylinder 12 by a step 12 b formed on the inner periphery of the cylinder 12 and a stopper 37. One end of the intermediate rod 32 directly contacts the pressing member 23, and the other end is a spring receiving portion 32b. The intermediate rod 32 has a passage 32 a extending in the axial direction. The passage 32 a connects the passage 12 a of the cylinder 12 and the passage 23 a of the pressing member 23.

The first spring 33 includes an intermediate rod 3
The second spring receiving portion 32b is disposed between a spring receiving member 38 that contacts the operation rod 31. The second spring 34 is disposed between the spring receiving portion 32b of the intermediate rod 32 and the support 36. First spring 33
Has a smaller spring constant than the second spring, and its ratio is, for example, 1: 5. The intermediate rod 32 receives forces in directions opposite to each other by the first and second coil springs 33 and 34, and at a position where both forces are balanced,
It comes to stand still. The second spring 34
, The force of the return spring 24 of the decompression cartridge 20 also acts. However, in this embodiment, the force of the return spring 24 is sufficiently smaller than the springs 33 and 34, so that the position of the intermediate rod 32 is hardly affected. Do not give.

Next, the flow detecting section B will be described. The flow detecting section B has a cylindrical body 40. The body 40 has an axially extending passage 40a (pseudo leakage passage).
have. A flange 40c is formed at the end of the body 40 on the side of the pressure reducing section A.
Is detachably connected to the end of the cylinder 12 using bolts or the like (not shown). The case 21 of the pressure reducing cassette 20 described above is supported by being sandwiched between a step 12c formed on the inner periphery of the cylinder 12 and a flange portion 40c. Flange part 40c and case 21 of decompression cassette 20
The bottom wall 21b is airtight, and the passage 26 (see FIG. 4) of the decompression cartridge 20 and the passage 40a of the body 40 are connected to each other.

A support hole 40c connected to the passage 40a is formed at an end of the body 40 opposite to the pressure reducing section A. The flow resistance unit 41 is provided in the support hole 40c.
Are accommodated. As shown in FIGS. 3 and 5, the flow resistance unit 41 includes a linear thin tube 42.
And a support 43 for fixing the base end of the thin tube 42. The flow resistance unit 41 includes a protection cylinder 44
The airtight connection to the body 40 is made. That is,
The support 43 is airtightly screwed into the protection tube 44, and the protection tube 44 is airtightly screwed into the support hole 40 c of the body 40. The thin tube 42 is protected by being surrounded by a protection tube 44. The proximal end of the thin tube 42 is connected to the passage 40 of the body 40.
a and the other end is open to the atmosphere.

A relief valve 46 and a pressure sensor 47 are attached to the body 40. The relief valve 46 opens and closes a valve port 40x connected to the passage 40a, and normally closes the valve port 40x. When the relief valve 46 is opened, the passage 40a communicates with the atmosphere via the valve port 40x. Has become. The pressure sensor 47 detects the pressure of the passage 40a.

The operation of the air leak tester provided with the pseudo leak device 9 having the above configuration will be described. When performing an air leak test on a workpiece to be inspected at a desired test pressure, the air leak tester first executes a setting mode for setting a relationship between a differential pressure detected by the differential pressure sensor 6 and an atmospheric pressure-converted leak amount. After that, the actual air leak test is repeatedly executed for a long time. In addition, an inspection mode for checking whether or not the differential pressure sensor 6 operates normally is periodically executed.

First, the setting mode will be described. In this setting mode, the flow rate in the simulated leak device 9 is adjusted as a previous step. That is, with the work capsule 5a and the master capsule 5b closed, the three-way solenoid valve 3 is turned on to bring the test pressure to a start state. The stop valve 15 is opened before and after the on-operation of the three-way solenoid valve 3 to cause a pseudo leak. The test pressure air is supplied to the passages 11a, 31a, 1
It passes through 2a, 32a, and 23a and reaches the pressure reducing element 22. Then, in the process of passing through the pressure reducing element 22, the pressure is reduced to a pressure close to the atmospheric pressure by the flow resistance, and then the passages 26, 40
a, and is further released to the atmosphere via the thin tube 42. Due to the flow resistance in the thin tube 42, a pressure slightly higher than the atmospheric pressure remains in the passage 40a of the flow detecting unit B. This pressure (differential pressure from the atmospheric pressure) is detected by the pressure sensor 47. This detected pressure has a linear relationship with the flow rate.

The detected pressure of the pressure sensor 47 is sent to the controller 7 and displayed on the display 8. The operator turns the operating rod 31 while watching the detected pressure on the display 8 to set the desired pressure (ie, the desired flow rate). This adjustment work will be described in detail. Operation rod 31
Is in a threaded relationship with the cylinder 11, and moves forward and backward with respect to the cylinder 12 by the above-described rotation operation. When the operating rod 31 advances, the intermediate rod 32 also advances via the first spring 33, and the pressing member 2 abutting on the intermediate rod 32
3 compresses the pressure reducing element 22. As a result, the pressure reducing element 22
The flow resistance at the outlet increases and the flow rate decreases. Conversely, when the operating rod 31 is retracted, the intermediate rod 32 is retracted by the force of the second spring 34, and the pressing member 23 is retracted by the force of the return spring 24. The resistance decreases and the flow increases.

The flow rate can be finely adjusted by using a pressure reducing element 22 made of a porous foamed resin. This is because the minute passage of the pressure reducing element 22 gradually narrows according to the degree of compression. Moreover, in this embodiment, finer adjustment can be performed than the springs 33 and 34. That is, the spring constant of the first spring 33 is
4 is smaller than, for example, 1: 5, so that when the operating rod 31 moves by one pitch, the intermediate rod 32
This is because the (the pressing rod 23) moves only by 1/5 pitch.

Next, this step is executed. That is, the work capsule 5a accommodates the work W having no leakage, and the master capsule 5b accommodates the work W without leakage as the master member M. In this state, the controller 7 controls the solenoid valves 3, 4a, 4b. First, the three-way solenoid valve 3 is set to the test pressure applying position, and the test pressure is applied to the branch passages 1a, 1b, the work capsule 5a, and the master capsule 5b.

Next, the two-way solenoid valves 4a and 4b are closed. As a result, a work-side closing system is formed by the branch passage 1a downstream of the two-way solenoid valve 4a and the work capsule 5a, and the master is defined by the branch passage 1b downstream of the two-way solenoid valve 4b and the work capsule 5b. A side closure system is formed. Since these closed systems are independent of each other and each have a test pressure, the differential pressure detected by the differential pressure sensor 6 is zero. Next, the stop valve 15 of the pseudo leak device 9 is opened. As a result, the pseudo leak device 9 generates a pseudo leak at the flow rate determined in the previous step. Immediately after the opening operation of the stop valve 15, a start button (not shown) is pressed. In response to the ON operation of the start button, the controller 7 receives the detected differential pressure from the differential pressure sensor 6 for a predetermined time. Then, from the value obtained by multiplying the flow rate by a predetermined time, that is, the atmospheric pressure-conversion leakage amount, and the change in the detected differential pressure, a proportional constant K between the two is obtained and stored. It should be noted that since the pseudo leakage amount is small compared to the volume of the closed system, the leakage amount and the differential pressure change amount have a linear relationship.

The proportionality constant K may be obtained based on the data of the detected differential pressure change in the pseudo leak at one flow rate. However, in order to ensure accuracy, the data of the detected differential pressure change corresponding to a plurality of flow rates are obtained. May be used to determine the proportional constant. When obtaining a plurality of data, the above-described pre-process and the present process are respectively performed a plurality of times. The flow rate at the time of simulated leakage is determined by the operation rod 31
By turning, it can be changed easily.

In the preceding step, the work capsule 5
a, the master capsule 5b may contain the work W and the master member M without leakage, respectively. After the completion of the preceding step and the present step, the relief valve 46 is temporarily opened to release the pressure remaining in the passage 40a.

After the setting mode, a test mode is executed. More specifically, in a state where the work W to be inspected and the master member M are accommodated in the respective capsules 5a and 5b,
The controller 7 sets the three-way solenoid valve 3 to the test pressure application position, and then closes the two-way solenoid valves 4a and 4b to close the work side.
The branch passages 1a and 1b on the master side are closed. Then, the detected differential pressure ΔP from the differential pressure sensor 6 after a lapse of a predetermined time (since the differential pressure is zero when the system is closed, the detected differential pressure ΔP represents a change in the differential pressure from that time). And the detected pressure difference ΔP is multiplied by the proportionality constant K to calculate an atmospheric pressure conversion leakage amount L, which is displayed on the display 8. When the leakage amount L is less than the threshold value, it is determined that the product is good, and when it exceeds the threshold value, it is determined that the product is defective and a warning is issued.

In the test mode, the pseudo leak device 9
Is connected to the branch passage 1a, and the stop valve 1
5 is closed. In this test mode, the pseudo leak device 9 may be removed, and the connection portion of the branch passage 1a to the pseudo leak device 9 may be airtightly closed with a stopper.

In the inspection mode performed periodically, the previous step and the main step are performed in the same manner as in the setting mode described above. Since the pre-process is the same as the setting mode, the description is omitted. In this process,
The solenoid valves 3, 4a, 4b operate in the same manner as in the setting mode.
In the inspection mode, the controller 7 inspects whether the differential pressure sensor 6 outputs a differential pressure corresponding to the flow rate set in the previous process. If they match, it is determined that the differential pressure sensor 6 is normal, and then the test mode is performed. If they do not match, it is determined that the differential pressure sensor 6 is abnormal, and repair or replacement is performed.

Since the pressure reducing element 22 is porous, it may be clogged with minute dust. In such a case, the body 40 of the flow detection unit B may be removed from the cylinder 12 of the pressure reduction unit A, and the pressure reduction cartridge 20 may be replaced.

In the present embodiment, since the pressure in the passage 40a of the flow rate detecting section B can be reduced to a pressure close to the atmospheric pressure by the pressure reducing element 22, the thin tube 42 does not need to be made very thin, and the occurrence of clogging can be suppressed. . Also, the pressure sensor 4
Since 7 detects the difference between the atmospheric pressure and the pressure in the passage 40a close to the atmospheric pressure, the linearity of the flow rate and the pressure can be secured with high accuracy.

FIG. 6 shows another embodiment of the present invention.
This will be described with reference to FIG. In these embodiments, components corresponding to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

FIG. 6 shows a pseudo-leakage device according to a second embodiment of the present invention. In this pseudo leak device, a tube 50 is used instead of the tube 12 of the first embodiment. This cylinder 5
0 is provided with a bottom wall 51 (receiving portion).
A hole 52 is formed at the center of 1. The internal space of the tube 50 becomes a passage 50a (pseudo leakage passage). In the cylinder 50,
The pressure reducing element 22, the pressing member 23, and the return spring 24 are housed in the same manner as in the first embodiment, but the case 21 of the first embodiment is not housed and does not constitute a unitized pressure reducing cartridge. As in the first embodiment, the operation rod 31 of the adjustment mechanism 30 is inserted into the cylinder 50, and the intermediate rod 32, the first spring 33, the second spring 34, and the spring receiving member 38 are housed in the cylinder 50. The pin portion 23b of the pressing member 23 is connected to the hole 52 through a gap.
Has been inserted.

A support 55 for slidably supporting the intermediate rod 32 and receiving the second spring 34 includes:
It is not fixed to the cylinder 50, and one end thereof contacts the bottom wall 51. In the present embodiment, no passage is formed in the intermediate rod 32 and the pressing member 23, and instead, the passage 50 a of the cylinder 50 and the minute passage of the pressure reducing element 22 are connected via a hole 55 a formed in the support 55. ing. In this embodiment, the number of parts is smaller than in the first embodiment,
The passage configuration is also simple.

FIG. 7 shows a pseudo-leakage device according to a third embodiment of the present invention. This device has a substantially rectangular parallelepiped block 60. This block 60 also serves as a body for the pressure reducing unit and the flow detecting unit. This block 6
At 0, an upstream passage 60a, an intermediate passage 60b, and a downstream passage 60c are formed. The passages 60a and 60b constitute a pseudo leak passage of the pressure reducing unit, and the downstream passage 60c constitutes a pseudo leak passage of the flow rate detecting unit.

On one surface 60x of the block 60, a connection port 60d connected to the upstream passage 60a is formed.
This connection port 60d is connected to the branch passage 1a in FIG. 1 via a pipe. Further, a connection port 60e connected to the downstream passage 60c is formed on the surface 60x, and a flow resistance unit including a thin tube is attached to the connection port 60e as in the first embodiment.

In the block 60, the surface 60x
A stop valve 15 is provided on a surface 60y perpendicular to the upstream passage 6 and the upstream passage 6.
0a is distributed and blocked.

The intermediate passage 60b is formed by a part of a large-diameter hole 61 penetrating the block 60 perpendicular to the surface 60y. The operation rod 32 is hermetically inserted into the end of the hole 61. This operation rod 31
Is screwed to a screwing member 62 projecting from the surface 60y and fixed to the surface 60y (the screwing member 62 forms a part of the body of the decompression unit).

The other end of the through hole 61 has a large diameter portion, in which the decompression cartridge 20 is housed.
The decompression cartridge 20 includes a step of the through hole 61 and a holding plate 63.
(The presser plate 63 forms a part of the body of the flow rate detector.) The holding plate 63 is detachably connected to the block 60 and is in airtight contact with the bottom wall 21 b of the case 21 of the decompression cartridge 20.
A passage 63a (which constitutes a part of a pseudo leakage passage of the flow rate detecting unit) is formed in the holding plate 63, and the passage 63a is formed.
Connects the passage 26 of the pressure reducing cartridge 20 and the downstream passage 60c.

The block 60 further includes a relief valve 4
6 and a pressure sensor 47 are attached, and the relief valve 46 and the pressure sensor 47 face the downstream side passage 60c, and play the same role as in the first embodiment.

In this embodiment, one pressing spring 6
5 is accommodated in the intermediate passage 60b and is interposed between the pressing member 23 and the operation rod 31. Return spring 24
Is stronger than the return spring of the first embodiment. The spring constant of the pressing spring 65 is smaller than the spring constant of the return spring 24, and the ratio is, for example, 1: 5.

In this embodiment, the body of the pressure reducing section and the flow rate detecting section are shared by the block 60,
4 is stronger than the pressing spring 65 and the second spring 34 and the intermediate rod 32 of the first embodiment are omitted, and the structure is simplified.

FIG. 8 shows a pseudo-leakage device according to a fourth embodiment of the present invention. In the present invention, the body of the pressure reducing section A is constituted by one cylinder 70. The internal space of the cylinder 70 becomes a passage 70a (pseudo leakage passage). A connection port 70b is formed in the peripheral wall of the cylinder 70, and the connection port 70b
The passage 70a is connected to the branch passage 1a of the air leak tester via a pipe connected to the air leak tester. The pipe is provided with a stop valve.

The pressure reducing cartridge 20 is housed in one end of the cylinder 70 in the same manner as in the first embodiment, and the operating rod 31 is hermetically inserted in a screwed state in the other end. The knob 75 of the adjusting mechanism 30 is connected to the operation rod 31 by a flexible tube 76 having high torsional rigidity.

The pseudo leak device is housed in a housing 80 together with other components of the air leak tester. The knob 75 is rotatably supported by the wall 81 of the housing 80, and is provided outside the housing 80.
When the rotating operation of 5 is performed, the operating rod 31 is rotated via the flexible tube 76 so that the flow rate can be adjusted. The cylinder 40 of the receiving portion B is supported by a wall 82 of the housing 80 facing the wall 81. This wall 8
From 2, a protective tube 44 and a thin tube 42 project outside the housing 80.

The present invention is not limited to the above embodiment, but can adopt various forms. For example, in the differential pressure type air leak tester, the branch passage on the master side may be closed without connecting the capsule. Further, the pseudo leakage device may be connected to a branch passage on the master side. A work may be directly connected to the work-side branch passage instead of the work capsule, or a master container may be directly connected to the master-side branch passage instead of the master capsule. The air leak tester need not be a differential pressure type. A two-way valve is provided in one air passage, a pressure sensor is provided on the downstream side, and a work capsule or a work is connected to the downstream end.

The test pressure source may be a negative pressure source. Even in this case, the configuration of the above-described embodiment can be used as it is. The pressure reducing element acts to bring the test pressure closer to the atmospheric pressure. That is, it acts to reduce the difference between the test pressure and the atmospheric pressure. In this case, the side closer to the test pressure source is the upstream side, and the atmosphere side is the downstream side.

[0059]

As described above, according to the pseudo leak device of the present invention, it is possible to obtain a direct relationship between the atmospheric pressure-converted leak amount and the change in the detected pressure, thereby saving the trouble of finding the work volume and the like. be able to. Also, a pseudo leak of a different flow rate can be generated only by changing the compression degree of the pressure reducing element by the adjusting means without replacing the components. further,
Since the pressure reducing element has a large number of minute passages and can change the flow resistance in these minute passages according to the degree of compression,
Fine adjustment of the flow rate can be made.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an air leak tester with a pseudo leak device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing the entire structure of the pseudo leakage device.

FIG. 3 is an enlarged longitudinal sectional view showing a main part of the pseudo leakage device.

FIG. 4 is an enlarged cross-sectional view showing a decompression cartridge incorporated in a decompression unit of the pseudo leak device.

FIG. 5 is an enlarged cross-sectional view showing a flow resistance unit incorporated in a flow detection unit of the pseudo leak device.

FIG. 6 is an enlarged sectional view of a main part showing a pseudo leakage device according to a second embodiment of the present invention.

FIG. 7 is an enlarged sectional view showing a pseudo leakage device according to a third embodiment of the present invention, with a part thereof omitted;

FIG. 8 is an enlarged cross-sectional view illustrating a main part of a pseudo leakage device according to a fourth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List A pressure reducing section B flow rate detecting section 9 pseudo leak device 10 body of pressure reducing section 12a pseudo leak path of pressure reducing section 20 pressure reducing cartridge 21 case 21b bottom wall (receiving part) of case 21c hole 22 pressure reducing element 23 pressing member 23b pin portion 24 return Spring 26 Passage 30 Adjusting mechanism 31 Operating rod (operating member) 32 Intermediate rod (Intermediate member) 33 First spring 34 Second spring 40 Body of flow detection unit 40a Pseudo leak passage of flow detection unit 41 Flow resistance unit 42 Thin tube 47 Pressure Sensor 60 Block (body of decompression unit and flow detection unit) 60a, 60b Pseudo leakage passage of decompression unit 60c, 63a Pseudo leakage passage of flow detection unit 65 Press spring 70 Tube (body of decompression unit) 70a Pseudo leakage passage of decompression unit

Claims (8)

[Claims] 1. A pseudo-leakage device connected to an air passage of an air leak tester together with a pressure sensor, a pressure reducing portion for reducing a test pressure from the air passage, and a flow rate connected between the pressure reducing portion and the atmosphere. A detecting unit, wherein the decompressing unit is a body having a pseudo leak passage, an elastically deformable decompressing device having a large number of minute passages disposed in the pseudo leak passage, and pressing and compressing the depressurizing device. A pressure member for adjusting the position of the pressure member to adjust the degree of compression of the pressure-reducing element, and thus adjusting the flow rate of air passing through the flow rate detection unit. Simulated leak device. 2. The pseudo leak device for an air leak tester according to claim 1, wherein said pressure reducing element is made of a continuous porous foamed resin. 3. The false leak passage according to claim 1, wherein a receiving portion having a hole is provided in the pseudo leak passage, and the pressure reducing element is disposed between the receiving portion and the pressing member. Pseudo leak device for air leak tester. 4. The pressing member has a pin portion which penetrates the pressure reducing element and is inserted into a hole of the receiving portion, and a gap between an outer periphery of the pin portion and an inner periphery of the hole is formed by air. The pseudo leak device for an air leak tester according to claim 3, wherein the pseudo leak device is a passage. 5. A case having an opening at one end and a bottom wall at the other end is disposed in the pseudo leak passage, and the bottom wall is provided as the receiving portion. A pressure reducing cartridge unitized by containing the return spring is formed, a pressure reducing element is sandwiched between the pressing member and the bottom wall, and the pressing member is urged in a direction away from the pressure reducing element by the return spring. 5. The pseudo leak device for an air leak tester according to claim 3, wherein movement in the same direction is restricted by a stopper provided in the case. 6. An operating member screwed to a body of the pressure reducing section and hermetically inserted into the pseudo leak passage, and an adjusting member interposed between the pressing member and the pressing member, An intermediate member directly in contact with the first spring, a first spring disposed between the intermediate member and the operating member for urging the intermediate member toward the pressure reducing element, and a second spring for urging the intermediate member away from the pressure reducing element The pseudo-leakage device for an air leak tester according to claim 3, wherein a spring constant of the first spring is smaller than a spring constant of the second spring. 7. An operating member screwed to a body of the pressure reducing section and hermetically inserted into the pseudo leak passage, and a pressing member interposed between the pressing member and the operating member. A pressure spring that urges the pressure member toward the pressure reducing element; and a return spring that is interposed between the pressure member and the receiving portion and urges the pressure member in a direction away from the pressure reducing element. The pseudo leak device for an air leak tester according to any one of claims 3 to 5, wherein is smaller than a spring constant of the return spring. 8. The flow rate detecting section includes a body having another pseudo leak passage, a thin tube, and another pressure sensor, and the other pseudo leak path includes the pseudo leak path of the pressure reducing section and the pressure reducing element. 2. The method according to claim 1, wherein the thin tube is disposed between the other pseudo leak passage and the atmosphere, and the other pressure sensor detects the pressure of the other pseudo leak passage. Pseudo leak device for air leak tester.