JP5081052B2 - Leak test system - Google Patents

Description

  The present invention relates to a leak test system using a tracer gas such as helium gas.

  A system using a tracer gas such as helium gas is known as a leak test system for inspecting the work for scratches. This type of leak test system includes a sealed container that accommodates a workpiece, a supply unit that supplies pressurized tracer gas to either the first space inside the workpiece or the second space inside the sealed container, 1 and a detecting means for detecting the tracer gas leaking into the other of the second spaces.

  The helium leak test system disclosed in Patent Document 1 includes recovery means for recovering the helium gas provided for the leak test, and return means for returning the recovered helium gas to the supply means. The gas is reused. Helium gas recovery prevents helium gas from escaping into the room where the leak test system is located, thereby preventing an increase in the background level of helium gas in this room and preventing a decrease in leak test accuracy. It also has a role.

  The present applicant has developed a system in which Patent Document 1 is further improved. In this system, the supply means has a supply tank for storing high-pressure helium gas, the recovery means has a recovery tank for storing recovered low-pressure helium gas, and the return means has a booster.

The booster includes a cylinder, a piston that is accommodated in the cylinder and partitions a space in the cylinder into a first chamber and a second chamber, and a drive unit that reciprocates the piston in the axial direction of the cylinder. The cylinder has an inlet port and an outlet port connected to the first chamber, the inlet port is connected to the recovery tank via an inlet check valve, and the outlet port has an outlet check valve. To the supply tank.
When the piston of the booster is reciprocated, the low-pressure helium gas in the recovery tank is boosted and supplied to the recovery tank.
Japanese Patent Laid-Open No. 10-311770

  In the leak test system described above, the helium gas leaks into the room where the system is located, but the background level of the helium gas gradually rises by repeating the test, and the accuracy of the leak test is increased. There was a possibility of incurring a decline.

  In order to solve the above-described problems, the present invention provides a sealed container that accommodates a workpiece and a supply unit that supplies pressurized tracer gas to either the first space inside the workpiece or the second space inside the sealed container. A detecting means for detecting the tracer gas leaking to the other of the first and second spaces, a collecting means for collecting the tracer gas from the one space after the detecting step by the detecting means, and the collecting means Return means for returning the collected tracer gas to the supply means, and the return means comprises pressure increase means for increasing the pressure of the tracer gas from the recovery means and returning it to the supply means. A first inlet check valve and a first outlet check valve, wherein the booster includes a cylinder and a piston that is accommodated in the cylinder and partitions a space in the cylinder into a first chamber and a second chamber; This fixie And a drive section for reciprocating the cylinder in the axial direction of the cylinder, wherein the first chamber of the cylinder is connected to the recovery means via the first inlet check valve, and the first outlet check valve is In the leak test system connected to the supply means, a second inlet check valve and a second outlet check valve are further provided, and the second chamber of the booster includes the second inlet check valve. And connected to the space outside the booster and connected to the outside of the room in which the leak test system is arranged through the exhaust circuit provided with the second outlet check valve.

  According to the above configuration, when the pressure of the tracer gas is increased by reciprocating the piston with the booster, and the tracer gas is returned from the recovery means to the supply means, a trace amount of tracer gas passes between the cylinder and the piston of the booster, There is a possibility of leakage from the first chamber to the low pressure second chamber. However, in the present invention, the pumping action associated with the reciprocating motion of the piston is performed also in the second chamber, and air outside the booster flows into the second chamber via the second inlet side check valve, and a minute amount in the second chamber. Since the air containing the tracer gas is discharged out of the room where the leak test system is arranged, the tracer gas is not accumulated in the room, and a highly accurate leak test can be performed.

  Preferably, the supply means has a supply tank for storing a tracer gas to be supplied to one of the first and second spaces, and has a recovery tank for storing the tracer gas recovered by the recovery means, and the booster The first chamber is connected to the recovery tank via the first inlet check valve, and is connected to the supply tank via the second inlet check valve.

Preferably, at least a booster of the boosting means is housed in a sealed housing, and pressurized air from a compressed air source is supplied to the sealed housing via an air supply circuit, and the supplied air passes through another exhaust circuit. The air is exhausted to the outside of the room where the leak test system is arranged.
According to this configuration, even if the tracer gas leaks from the booster, it can be received by the hermetically sealed housing and discharged to the outside of the part, so that the accumulation of the tracer gas in the room can be prevented more reliably.

Preferably, an intake circuit provided with the second inlet check valve is connected to the second chamber of the booster, and the intake circuit is connected to a space outside the sealed housing.
According to this, since the air outside the sealed housing is introduced into the second chamber at the time of the pressure increasing action, the tracer gas can be discharged efficiently.

  ADVANTAGE OF THE INVENTION According to this invention, it can avoid that tracer gas accumulates in the room where the leak test system is arrange | positioned, and can perform a highly accurate leak test.

  Hereinafter, a leak test system according to the present invention will be described with reference to the drawings. This leak test system is arranged in an examination room. As shown in FIG. 1, as shown in FIG. 1, a sealed container 10 that houses a work W, an exhaust means 20 that exhausts the sealed container 10, and a work W to the sealed container 10. Detection means 30 for detecting leakage to helium gas (tracer gas), supply means 40 for supplying helium gas to the work W, recovery means 50 for recovering helium gas from the work W, and exhaust for exhausting the work W Means 60 and a return means 70 for returning the helium gas recovered by the recovery means 50 to the supply means 40 are provided as a basic configuration.

The sealed container 10 includes a container main body 11, a lid 12 that opens and closes the container main body 11, and driving means 13 such as a cylinder device that opens and closes the lid 12.
The workpiece W is connected to the connector 15 in the sealed container 10. In this state, the internal space 1 (first space) of the work W and the internal space 2 (second space) of the sealed container 10 are blocked by the work W.

  The sealed container 11 has a suction port 16 and an air introduction port 17. The air introduction port 17 is connected to the inspection room (the room where the leak test system is arranged) via the open / close valve 18 or is connected to the outdoors (outside of the inspection room) via the duct. The exhaust means 20 and the inspection means 30 are connected to the suction port 16.

The exhaust means 20 includes an exhaust circuit 21 connected to the suction port 16, an on-off valve 22 and exhaust pumps 23 and 24 provided in this exhaust circuit 21 in order from the upstream side.
The detection means 30 includes a detection circuit 31 connected to the suction port 16, and an on-off valve 32, a helium detector 33, and an exhaust pump 34 provided in this detection circuit 31 in order from the upstream side.
The downstream ends of the exhaust circuit 21 and the detection circuit 31 are connected to the outdoors via an exhaust duct.

  The connector 15 is connected to the supply means 40, the recovery means 50, and the exhaust means 60 through a connection circuit 19.

The supply means 40 includes a supply circuit 41 connected to the connection circuit 19, and an opening / closing valve 42, a supply tank 43, a pressure reducing valve 44, and an opening / closing valve 45 provided in this supply circuit 41 in order toward the downstream side. ing.
A helium gas source 47 is connected to the supply tank 43 via an opening / closing valve 46, and when the pressure detected by the pressure sensor 48 provided in the supply tank 43 falls below a predetermined pressure, the opening / closing valve 46 opens to open helium. Helium gas is supplemented from the gas source 47.

  The recovery means 50 includes a recovery circuit 51 connected to the connection circuit 19, and an open / close valve 52, a recovery device 53, an open / close valve 54, a recovery tank 55, an open / close A valve 56 is provided.

  The exhaust means 60 includes an exhaust circuit 61 connected to the connection circuit 19, an on-off valve 62 and an exhaust pump 63 provided in this exhaust circuit 61 in order toward the downstream side.

  The return means 70 includes a return circuit 71 that connects the upstream end of the supply circuit 41 and the downstream end of the recovery circuit 51, and a boosting means 72 provided in the return circuit 71. The booster 72 has a booster 80, a first inlet check valve 73, and a first outlet check valve 74.

Next, the detailed structure of the booster 80 will be described with reference to FIGS. The booster 80 includes a booster 80A and a drive unit 80B.
The pressure increasing unit 80 </ b> A includes a cylinder 81 and a piston 82 accommodated in the cylinder 81. The cylinder 81 has an internal space defined by a cylinder 81 a and end members 81 b and 81 c fixed at both ends thereof, and the internal space is partitioned by the first chamber 83 and the second chamber 84 by the piston 82. .

  The end member 81b of the cylinder 81 is formed with a first inlet port 81x and a second outlet port 81y. The first chamber 83 includes the first inlet port 81x and the first inlet side check. The valve is connected to the recovery tank 55 of the recovery means 50 via a valve 73 and is connected to the supply tank 43 of the supply means 40 via a second outlet port 81 y and a first outlet check valve 74.

  The piston 82 is reciprocated by the drive unit 80B. The drive unit 80B is composed of an air cylinder device. The cylinder 85 has a larger diameter than the cylinder 81 of the booster 80A, a piston 86 accommodated in the cylinder 85, the piston 85, and the piston 82 of the booster 80A. And a rod 87 for connecting the two.

  Pressurized air is alternately supplied to the two chambers of the cylinder 85 partitioned by the piston 86, thereby causing the piston 86 to reciprocate and a booster 80A connected to the piston 86. The piston 82 is reciprocated. When the piston 82 moves away from the end member 81b, the low-pressure helium gas in the recovery tank 55 is sucked into the first chamber 83 via the first inlet check valve 73, and the piston 82 moves toward the end member 81b. Then, the pressure of the helium gas in the first chamber 83 is increased and returned to the supply tank 43 via the first outlet check valve 74.

  Since the diameter of the piston 86 of the driving unit 80B is larger than the diameter of the piston 82 of the boosting unit 80A, the pressure of helium gas in the first chamber 83 can be higher than the driving air pressure in the driving unit 80B.

  Next, the structure of the characteristic part of this invention is demonstrated, referring FIG. 1, FIG. A second inlet port 81x 'and a second outlet port 81y' are also formed in the end member 81c of the cylinder 81 of the booster 80A. The second inlet port 81x ′ is connected to the inspection room (the room where the leak test system is arranged) via the intake circuit 92 provided with the second inlet side check valve 91, and the second outlet port 81y ′ It continues to the outdoors via an exhaust circuit 94 (including an exhaust duct) provided with a second outlet check valve 93.

As shown in FIG. 1, the booster 72 is housed in a hermetically sealed housing 95. A downstream end of an air supply circuit 96 is connected to the housing 95, a compressed air source 97 is connected to the upstream end of the air supply circuit 96, and a pressure reducing valve 98 and an on-off valve 99 are disposed in the middle of the air supply circuit 96. Is provided. Further, an exhaust circuit 100 (including an exhaust duct) is connected to the housing 95 at a location away from the connection location of the air supply circuit 96, and the housing 95 is connected to the outdoors via the exhaust circuit 100.
The intake circuit 92 is connected to the inspection room outside the housing 95, but may be connected to the outdoors.

The operation of the leak test system configured as described above will be described in the order of steps.
First, the workpiece W is connected to the connector 15 and the sealed container 10 is sealed. The connector 15 has valve means and is opened when the workpiece is connected.
All of the on-off valves used in the system are normally closed, and are closed except when referring to the opening operation in the description of operation described below.

  Next, the on-off valve 22 of the exhaust means 20 is opened, and the second space 2 in the sealed container 10 is depressurized and vacuumed by driving the pumps 23 and 24. Further, the opening / closing valve 62 of the exhaust means 60 is opened and the pump 63 is driven to evacuate the first space 1 of the workpiece W.

  Next, the on-off valve 45 of the supply means 40 is opened, and pressurized helium gas from the supply tank 43 is supplied to the first space 1 of the workpiece W and maintained for a predetermined time. If the workpiece W is scratched, helium gas leaks into the second space 2 of the sealed container 10.

  After the predetermined time has elapsed, the on-off valve 32 is opened, and helium gas leaked by driving the pump 34 is guided to the detector 30. As a result, it is possible to determine whether or not the workpiece W is scratched.

After the detection step, the on-off valves 52 and 54 of the recovery means 50 are opened, and the helium gas of the workpiece W is sent into the recovery tank 55 by driving the recovery unit 53.
Next, the open / close valve 56 of the recovery means 50 and the open / close valve 42 of the supply means 40 are opened, and the booster 80 is driven to boost the low pressure helium gas in the recovery tank 55 and send it to the supply tank 43. In this way, helium gas can be reused.

After the recovery step, the on-off valve 62 is opened, and a small amount of helium gas left in the work W is discharged to the outdoors by driving the pump 63.
Next, the on-off valve 18 is opened to introduce the atmosphere into the second space 2 of the sealed container 10. At the same time, the atmosphere introduction circuit (not shown) connected to the connection circuit 19 is opened to introduce the atmosphere into the first space 1 of the workpiece W. Finally, the sealed container 10 is opened and the workpiece W is removed from the connector 15.

  Next, the operation of the characteristic part of the present invention will be described in detail. In the booster 80, the cylinder 81 and the piston 82 are sealed. However, when the booster 80 is driven, the helium gas boosted in the first chamber 83 passes between the cylinder 81 and the piston 82 and is low pressure. There is a possibility of leakage to the second chamber 84 on the side. Although the amount of leakage is very small, in a configuration in which the second chamber 84 is open to the examination room, helium gas accumulates in the examination room when the leak test is repeated for a long time, and the background level of the helium gas is reduced. As a result, the detection accuracy of the helium detector 33 is lowered.

  However, in the present invention, when the piston 82 reciprocates when the booster 80 is driven, the pumping action also works in the second chamber 84, and the helium gas in the second chamber 84 can be discharged to the outdoors. More specifically, when the piston 82 moves in a direction away from the end member 81 c of the cylinder 81, air in the examination room or outdoors is sucked into the second chamber 84 via the intake circuit 92 and the second inlet check valve 91. When the piston 82 moves in a direction approaching the end member 81c, the helium gas in the second chamber 84 is discharged to the outside via the exhaust circuit 94 and the second outlet check valve 93. As a result, an increase in the background level of the helium gas in the examination room can be avoided or suppressed, and a leak test can be performed with high accuracy.

  Further, since the pressure increasing means 80 is accommodated in the hermetic housing 95, even if a small amount of helium gas leaks from any part of the pressure increasing means 80, this helium gas is exhausted by the pressurized air from the compressed air source 97. You can escape from 100 outdoors. As a result, an increase in the background level of the helium gas in the examination room can be avoided more reliably.

The present invention is not limited to the above embodiment, and various aspects can be adopted. The exhaust circuits 94 and 100 may include a common exhaust duct connected to the outdoors.
The booster 100 may house only the booster as the main part in the housing 95, and the check valves 73 and 74 may be arranged outside the housing 95.
The drive unit may be electrically driven instead of air pressure driven.
After completion of the test, nitrogen may be supplied to the second space of the sealed container for cleaning.
The second space of the sealed container may be filled with tracer gas, and the tracer gas leaking into the first space of the workpiece may be detected. In this case, the tracer gas in the second chamber is recovered.

1 is a circuit diagram of a leak test system according to an embodiment of the present invention. It is a longitudinal cross-sectional view of the pressure | voltage rise means used in the embodiment.

Explanation of symbols

W Work 1 First space 2 Second space 10 Sealed container 20 Exhaust means 30 Detection means 40 Supply means 43 Supply tank 50 Recovery means 55 Recovery tank 60 Exhaust means 70 Return means 72 Boosting means 73 First entry side check valve 74 First 1 outlet check valve 80 booster 80A booster 80B drive unit 81 cylinder 82 piston 83 first chamber 84 second chamber 91 second inlet check valve 92 intake circuit 93 second outlet check valve 94 exhaust circuit 95 Housing 96 Air supply circuit 97 Compressed air source 100 Exhaust circuit

Claims (4)

A sealed container for accommodating the workpiece, a supply means for supplying pressurized tracer gas to either the first space inside the workpiece or the second space inside the sealed container, and the other of the first and second spaces Detecting means for detecting the tracer gas leaked to the tank, recovery means for recovering the tracer gas from the one space after the detection step by the detecting means, and returning the tracer gas recovered by the recovery means to the supplying means A return means,
The return means includes a pressure increase means for increasing the pressure of the tracer gas from the recovery means and returning it to the supply means. The pressure increase means has a booster, a first inlet check valve, and a first outlet check valve. And
The booster includes a cylinder, a piston that is accommodated in the cylinder and partitions a space in the cylinder into a first chamber and a second chamber, and a drive unit that reciprocates the piston in the axial direction of the cylinder. In the leak test system, the first chamber is connected to the recovery means via the first inlet check valve, and is connected to the supply means via the first outlet check valve.
Furthermore, a second inlet side check valve and a second outlet side check valve are provided, and the second chamber of the booster is connected to a space outside the booster via the second inlet side check valve. The leak test system is characterized in that the leak test system is connected to the outside of the room in which the leak test system is arranged through an exhaust circuit provided with the second outlet check valve. The supply means has a supply tank for storing tracer gas to be supplied to one of the first and second spaces, has a recovery tank for storing tracer gas recovered by the recovery means, and has a first tank for the booster. The leak test system according to claim 1, wherein a chamber is connected to a recovery tank via the first inlet check valve and is connected to a supply tank via the first outlet check valve .   At least a booster of the boosting means is accommodated in a sealed housing, and pressurized air from a compressed air source is supplied to the sealed housing through an air supply circuit, and the supplied air is supplied through another exhaust circuit, The leak test system according to claim 1 or 2, wherein the leak test system is exhausted outside a room in which the leak test system is arranged.   The intake circuit having the second inlet check valve is connected to the second chamber of the booster, and the intake circuit is connected to a space outside the sealed housing. The described leak test system.

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