JP2007315977A - Leakage inspection apparatus of fuel steam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an low-cost leakage inspection apparatus that can shorten the measurement time and having high inspection accuracy of the existence of leakage holes. <P>SOLUTION: The leakage inspection apparatus is provided with a partition plate 130 so as to block a gas flow passage route, other than an orifice 132 part on the gas flow passage route, where a gas circulates when the inside of a fuel tank 20 and the inside of a purge device 10 are pressure-reduced by a negative-pressure pump 150. The partition plate 130 can be rotated in the gas circulating direction by a rotating shaft 123. When the inside of the system is reduced in pressure by the negative-pressure pump 150, a differential pressure is generated in front and behind the partition plate 130, since the gas circulates the orifice 132. As a result, the partition plate 130 rotates and moves in a direction of the negative-pressure pump 150. If there is no leak holes, the partition plate 130 returns to the initial position since the differential pressure is eliminated gradually. If there is a leakage hole, since the differential pressure is not eliminated, the partition plate 130 will not return to the initial position. This is detected with a proximity sensor 142. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention inspects whether a leak hole having a predetermined diameter or more is generated in a fuel tank and a purge device that purges fuel vapor generated by evaporation of fuel in the fuel tank into an intake pipe of an engine. The present invention relates to a fuel vapor leak inspection apparatus.

  In order to prevent the fuel vapor generated from the fuel tank from leaking into the atmosphere, the fuel vapor generated from the fuel tank is adsorbed to the canister and provided in a purge pipe that connects the canister and the intake pipe of the engine. There is known a purge device that purges the fuel vapor adsorbed in the canister to the intake pipe by using the negative pressure of the intake pipe by opening the purge valve.

  There is also known a leak inspection device that inspects whether a fuel tank or purge device has a leak hole from the pressure when the pressure in the fuel tank or purge device is reduced or increased. For example, this is the device described in Patent Document 1.

The device disclosed in Patent Document 1 includes a negative pressure pump, a reference orifice having a predetermined diameter (for example, a diameter of 0.5 mm), and a gas flow path when the negative pressure pump is driven on the reference orifice side or a fuel tank. There is a switching valve that switches between the closed system side including the inside. And when inspecting the presence or absence of a leak hole, first, the flow path is set as the reference orifice side, and the pressure convergence value when the negative pressure pump is driven is set as the reference pressure. Next, the flow path is switched in a state where the purge valve is closed and the system including the fuel pump is a closed system, the closed system is depressurized by a negative pressure pump, and the pressure in the system after a predetermined time is compared with the reference pressure. . If the pressure in the system is higher than the reference pressure, it can be diagnosed that a hole larger than the reference orifice is open, and if the pressure drops below the reference pressure before the predetermined time has elapsed, Can be diagnosed as not open.
JP 2005-69877 A

  In the case of the device described in Patent Document 1, it is necessary to perform measurement in two stages, such as first measuring the reference pressure and then measuring the pressure in the closed system. There is a problem that it takes a relatively long time to check for the presence or absence. Here, if a large flow rate pump is used, the measurement time can be shortened even in the apparatus described in Patent Document 1. However, as the pump flow rate is increased, the amount of pressure change with respect to the change in flow rate decreases. . Therefore, since the amount of pressure change due to the flow rate change caused by the leak hole is reduced, there arises a problem that the detection accuracy is lowered.

  In addition, since a switching valve for switching the flow path and a pressure sensor for detecting pressure are required, there is a problem that the cost of the apparatus is high. Furthermore, it is necessary to form a closed system and measure the pressure in the closed system. Since one end of the closed system is sealed with a pump, a pump with a low leakage type such as a positive displacement pump is used. Although necessary, this type of pump is also expensive.

  Furthermore, if the suction capacity of the negative pressure pump is unstable and the pump capacity changes between the measurement of the reference pressure and the pressure in the closed system, the accuracy of detecting the leak hole will be reduced. There is also a problem.

  The present invention has been made on the basis of this circumstance, and the object of the present invention is to provide a leak inspection apparatus that can shorten the measurement time, has high inspection accuracy for the presence or absence of leak holes, and is inexpensive. It is to provide.

In order to achieve the object, the invention according to claim 1 is directed to a leak of a predetermined diameter or more in a purge device or a fuel tank that purges fuel vapor generated by evaporation of fuel in a fuel tank to an intake pipe of an engine. A fuel vapor leak inspection device for inspecting whether or not a hole has occurred,
A pump for transforming the inside of the fuel tank and the purge device, and an orifice having a predetermined diameter provided on a gas flow path through which gas flows when the inside of the fuel tank and the purge device is transformed by the pump. And a partition part that blocks the gas flow path except for the part where the orifice is formed, and a pressure difference reaction part that constitutes a part or all of the partition part and moves due to the pressure difference between the front and the back. The biasing member that biases the pressure difference reaction part in the direction opposite to the direction of movement due to the pressure difference and the position of the pressure difference reaction part are the initial positions when there is no pressure difference before and after And a position detecting device for detecting whether or not.

  In order to inspect the presence or absence of a leak hole with the thus configured leak inspection apparatus, first, the pump is driven in a state in which the purge valve is closed and the purge apparatus and the fuel tank are closed. When the pump is driven, gas flows through the gas flow path, so that the gas flows through the orifice of the partition portion provided on the gas flow path. As a result, a pressure difference is generated before and after the partition portion where the orifice is formed. Since the partition portion is provided with a pressure difference reaction portion that moves due to the pressure difference, the pressure difference reaction portion is moved by the pressure difference generated before and after the partition portion.

  Here, if there is no leak hole in the purge device and the fuel tank, the pressure difference reaction unit is once moved by the pressure difference between the front and rear, but the pressure in the closed space becomes a constant value determined by the pump capacity and the like. Since the gas no longer flows through the orifice and the pressure difference before and after the orifice disappears, the pressure difference reaction part is urged by the urging member and returns to the initial position. On the other hand, when there is a leak hole in the purge device or the fuel tank, external air is continuously introduced from the leak hole, so that the gas continues to flow through the orifice. In this case, since the pressure difference before and after the orifice does not disappear, the pressure difference reaction part does not return to the initial position. Therefore, after the pump is driven, the presence or absence of a leak hole can be inspected by detecting whether or not the pressure difference reaction member has once moved and then returned to the initial value using the position detection device.

  And according to this leak test | inspection apparatus, since it is not necessary to switch a flow path and to implement a measurement in two steps like the past, measurement time can be shortened. Further, since there is no need to switch the flow path, a switching valve for switching the flow path is not required, and no pressure sensor is required. For this reason, the apparatus becomes inexpensive. Further, the leak hole is inspected based on the pressure difference generated before and after the partition plate, and it is not necessary to form a closed system by sealing with the pump, so that there are few restrictions on the pump type. Therefore, a pump of a type that is less expensive than the positive displacement type, such as a flow rate type pump, can be used. In addition, since there is no need to measure in two stages, there is no decrease in detection accuracy due to fluctuations in pump capacity between the first stage pressure measurement and the second stage pressure measurement. The presence of leak holes can be inspected with high accuracy.

  Here, as for a pressure difference reaction part, the movement direction can be made into the direction which rotates to the surroundings of an axis perpendicular | vertical with respect to a gas distribution direction, for example.

  That is, in the invention according to claim 2, the pressure difference reaction part is rotatable around an axis perpendicular to the gas flow direction, and the orifice is formed in the pressure difference reaction part. It is characterized by.

  The invention described in claim 3 is different from claim 2 in that it has a fixed portion and an orifice is formed in the fixed portion. That is, in the invention according to claim 3, the partition portion has a fixed portion that is immovable with respect to the gas flow path, and the pressure difference reaction portion is fixed in the direction perpendicular to the gas flow direction. It is possible to rotate around a rotation axis provided in the part, and the orifice is formed in the fixed part.

  Further, as described in claim 4, the moving direction of the pressure difference reaction part may be the gas flow direction. According to a fourth aspect of the present invention, the partition portion includes a fixed portion that is immovable with respect to the gas flow path, and the pressure difference reaction portion can be separated from the fixed portion in the gas flow direction. In addition, when there is no pressure difference between the front and rear, it is biased by the biasing member so as to contact the fixed portion without a gap.

  The position detection device can be configured as described in claims 5 to 8. According to a fifth aspect of the present invention, the position detection device includes a magnet provided in any one of the gas flow pipes constituting the gas flow path in a portion where the pressure difference reaction part and the partition part are provided. And a magnetic proximity sensor provided on the other of the pressure difference reaction part and the gas flow pipe.

  The invention according to claim 6 is operatively connected to the pressure difference reaction part, and is configured so that the on / off state is switched between when the pressure difference reaction part is at the initial position and when it is not the initial position. It is an electrical switch.

  The invention according to claim 7 is characterized in that the position detection device is a photoelectric sensor that optically detects the position of the pressure difference reaction part.

  Further, in the case of Claims 2 and 3 in which the pressure difference reaction part rotates, the position detection device can be a rotation sensor that detects the rotation position of the pressure difference reaction part. .

  Hereinafter, embodiments of a leak inspection apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a purge apparatus 10 and a leak inspection apparatus 100 to which the present invention is applied. The purge device 10 includes a canister 30, a connection pipe 32, a valve pipe 33, and a purge valve 34. The connection pipe 32 connects the canister 30 and the fuel tank 20. The canister 30 is filled with an adsorbent 31 such as activated carbon. When fuel vapor generated in the fuel tank 20 is introduced into the canister 30 via the connection pipe 32, it is adsorbed by the adsorbent 31. .

  The valve pipe 33 connects the canister 30 and an intake pipe 41 that supplies air to an engine (not shown), and the purge valve 34 is provided in the middle of the valve pipe 33. The purge valve 34 is an electromagnetic valve whose opening degree can be adjusted. When the purge valve 34 is opened, the canister 30 and the intake pipe 41 are in communication with each other, so that the fuel vapor separated from the adsorbent 31 passes through the intake pipe 41. Purge (release) into the intake pipe 41 by the negative pressure.

  The leak inspection apparatus 100 for inspecting whether or not there is a leak hole in the purge apparatus 10 or the fuel tank 20 configured as described above includes a leak check module 110, an electronic control apparatus (hereinafter referred to as ECU) 200, and It has.

  The leak check module 110 includes a storage chamber 120, and a partition plate 130 as a partition portion is stored in the storage chamber 120. The storage chamber 120 has a rectangular tube shape, and both sides in the axial direction are closed by lid portions 121 and 122. A rotation shaft 123 is provided on a substantially central wall in the axial direction of the storage chamber 120 perpendicular to the axial direction. Note that a gap generated between the rotating shaft 123 and the storage chamber 120 is sealed with a sealing material so as to be sufficiently smaller than an orifice 132 described later.

  One side of the partition plate 130 is fixed to the rotation shaft 123, and the partition plate 130 can rotate about the rotation shaft 123. That is, in this embodiment, the whole partition plate 130 is a pressure difference reaction part, and when a pressure difference arises before and behind the partition plate 130, the whole partition plate 130 makes the rotating shaft 123 a rotation center by the pressure difference. Rotates to the negative pressure side.

  In the partition plate 130, an orifice 132 penetrating in the thickness direction is formed at the center. The diameter of the orifice 132 is set to the minimum diameter (for example, 0.5 mmφ) of the leak hole that needs to be detected by the leak inspection apparatus 100.

  Moreover, the planar shape of the partition plate 130 is the same shape as the cross-sectional shape when the storage chamber 120 is cut along a cross section perpendicular to the axis thereof. Therefore, in the state where the partition plate 130 is perpendicular to the axis of the storage chamber 120, the storage chamber 120 is closed in the axial direction by the partition plate 130 except for the portion where the orifice 132 is formed.

  One end of the canister communication pipe 140 is connected to one lid 121 in the axial direction of the storage chamber 120, and the storage chamber 120 is connected to the canister communication pipe 140 and the canister communication pipe 140. The canister 30 communicates with the pipe 35. Further, a negative pressure introducing pipe 141 is connected to the other lid portion 122 in the axial direction of the accommodating chamber 120, and the accommodating chamber 120 and the negative pressure pump 150 are communicated with each other by the negative pressure introducing pipe 141.

  In the storage chamber 120, a stopper 124 that comes into contact with the partition plate 130 when the partition plate 130 is perpendicular to the axial direction of the storage chamber 120 is opposite to the negative pressure pump 150 with respect to the partition plate 130. It is fixed to. The partition plate 130 is prevented from rotating further to the opposite side of the negative pressure pump 150 by the stopper 124. The position in contact with the stopper 124 is the initial position of the partition plate 130.

  One end of a spring 125 as an urging member is fixed near the rotation shaft 123 on the surface opposite to the stopper 124 side of the partition plate 130, and the other end is fixed to the storage chamber 120. Since the partition plate 130 is biased in the direction of the stopper 124 by the biasing force of the spring 125, the partition plate 130 is brought into contact with the stopper 124 when there is no pressure difference between the front and rear of the partition plate 130.

  In addition, a permanent magnet 126 is fixed to the surface of the partition plate 130 on the side where one end of the spring 125 is fixed, in the vicinity of the end opposite to the rotating shaft 123 side. A magnetic proximity sensor (hereinafter simply referred to as a proximity sensor) 142 detects the position of the partition plate 130 to which the permanent magnet 126 is fixed by detecting the position of the permanent magnet 126, and this proximity sensor 142 and the permanent magnet 126 constitute a position detection device. The proximity sensor 142 is disposed outside the position where the stopper 124 of the storage chamber 120 is fixed, and a signal from the proximity sensor 142 is supplied to the ECU 200.

  The negative pressure pump 150 includes an electric motor 152, and the electric motor 152 is controlled by a drive control circuit 154. As the negative pressure pump 150, a positive displacement type can be used as in the conventional case, but a non-positive type such as a centrifugal type can also be used.

  The drive control circuit 154 controls the rotation speed of the electric motor 152 by controlling electric power supplied from a battery (not shown) according to a drive signal from the ECU 200 and supplying the electric power to the electric motor 152.

  An air communication pipe 156 is connected to the negative pressure pump 150 on the exhaust side. The other end of the atmosphere communication pipe 156 is connected to the connection pipe 158, and the other end of the connection pipe 158 communicates with the atmosphere via the air filter 160.

  Next, the operation of the leak inspection apparatus 100 configured as described above will be described. In the inspection of the leak hole, the purge valve 34 is first closed. Thereby, the space from the purge valve 34 to the negative pressure pump 150 via the canister 30 and the space from the canister 30 to the fuel tank 20 form one closed space.

  When the negative pressure pump 150 is driven with the purge valve 34 closed, the pressure in the closed space is reduced, and the gas in the closed space flows in a direction from the purge valve 34 or the fuel tank 20 toward the canister 30. The canister 30 circulates to the connection pipe 35, the canister communication pipe 140, the storage chamber 120, and the negative pressure introduction pipe 141. The path through which the gas flows at this time is the gas distribution path. Further, the connection pipe 35, the canister communication pipe 140, the storage chamber 120, and the negative pressure introduction pipe 141 function as a gas flow pipe that constitutes a gas flow path.

  Since the orifice 132 is provided in the gas flow path, the gas flows through the orifice 132 from the canister 30 side to the negative pressure pump 150 side by driving the negative pressure pump 150, and thereby the partition in which the orifice 132 is formed. There is a pressure difference before and after the plate 130. Therefore, as shown by a two-dot chain line in FIG. 1, the partition plate 130 rotates toward the negative pressure pump 150 with the rotation shaft 123 as the rotation center.

  Here, if there is no leak hole in the purge device 10 and the fuel tank 20, the partition plate 130 is once moved by the pressure difference between the front and rear, but the pressure in the closed space is a constant value determined by the pumping capacity and the like. As a result, the gas does not flow through the orifice 132, and the pressure difference between the front and rear of the orifice 132 disappears. Therefore, the partition plate 130 is biased by the spring 125 and returns to the initial position.

  On the other hand, when there is a leak hole in the purge device 10 or the fuel tank 20, external air is continuously introduced through the leak hole, so that the gas continues to flow through the orifice 132. In this case, since the pressure difference before and after the orifice 132 does not disappear, the partition plate 130 does not return to the initial position. Therefore, after the negative pressure pump 150 is driven, the proximity sensor 142 is used to detect whether the partition plate 130 has once rotated and moved to the negative pressure pump 150 side and then returned to the initial value. The presence or absence of leak holes can be inspected.

  And according to the leak test | inspection apparatus 100 of this embodiment, since it is not necessary to switch a flow path and to implement a measurement in two steps like before, measurement time can be shortened. Further, since there is no need to switch the flow path, a switching valve for switching the flow path is not required, and no pressure sensor is required. For this reason, the apparatus becomes inexpensive. Further, the leak hole is inspected based on the pressure difference generated before and after the partition plate 130, and it is not necessary to form a sealed system by sealing with the negative pressure pump 150 located downstream of the partition plate 130. There are few restrictions on the pump type. Therefore, a pump of a type that is less expensive than the positive displacement type, such as a flow rate type pump, can be used. In addition, since there is no need to measure in two stages, there is no decrease in detection accuracy due to fluctuations in pump capacity between the first stage pressure measurement and the second stage pressure measurement. The presence of leak holes can be inspected with high accuracy.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, The following embodiment is also contained in the technical scope of this invention, and also the summary other than the following is also included. Various modifications can be made without departing from the scope.

  For example, in the above-described embodiment, the partition plate 130 serving as the pressure difference reaction unit is configured to rotate and move due to the pressure difference between the front and rear, but is parallel to the gas flow direction due to the pressure difference between the front and rear. May be. FIG. 2 is an example. In the example of FIG. 2, a fixing unit 300 fixed to the storage chamber 120 is provided, and the moving plate 310 as the pressure difference reaction unit is urged toward the fixing unit 300 by a coil spring 320 that is an urging member. Yes. A small cylindrical portion 302 is formed in the fixed portion 300 in parallel to the axial direction of the storage chamber 120, and gas can flow from one lid portion 121 to the other lid portion 122 inside the small cylindrical portion 302. It has become. In addition, an orifice 312 penetrating in the thickness direction is formed in the moving plate 310 substantially coaxially with the small tube portion 302.

  FIG. 2A shows a state in which the negative pressure pump 150 is stopped. The moving plate 310 is in contact with the fixed portion 300 without a gap, and the storage chamber 120 includes the fixed portion 300 and the moving plate 310. As a result, the portion other than the orifice 312 is blocked. Therefore, the fixed part 300 and the moving plate 310 constitute a partition part. When the negative pressure pump 150 is driven, as shown in FIG. 2B, the moving plate 310 is temporarily moved in the direction of the negative pressure pump 150 due to a pressure difference between the front and rear. Thereafter, whether or not the movable plate 310 returns to the initial position is detected by a position detection device (not shown in FIG. 2), so that the leak hole can be inspected.

  Further, in the above-described embodiment, the partition plate 130 as the partition portion does not include the fixing portion, and the entire plate can be moved by the pressure difference. However, as illustrated in FIG. It may be. In the example shown in FIG. 3, a fixing portion 400 fixed to the storage chamber 120 is provided, and the rotating shaft 123 is fixed to the fixing portion 400. The rotating plate 410 as the pressure difference reaction part rotates around the rotation shaft 123 fixed to the fixed part 400. In this case, the partition portion is configured by the fixed portion 400 and the rotating plate 410. The orifice 402 is formed in the fixed part 400. However, the orifice 402 may be formed in the rotating plate 410. Other configurations are the same as those of the above-described embodiment.

  In the above-described embodiment, the position detection device is configured by using the magnetic proximity sensor 142, but other types of proximity sensors such as a high-frequency oscillation type and a capacitance type may be used. Further, an electrical switch, a rotation sensor, or a photoelectric sensor may be used as the position detection device.

  FIG. 4 is a diagram illustrating an example in which an electric switch 500 is used as the position detection device. In this case, the first gear (not shown) configured to rotate integrally with the rotating shaft 123 and the second gear (not illustrated) configured to rotate integrally with the opening / closing plate 502 of the electric switch 500 are always meshed. The electric switch 500 is configured to open and close in conjunction with the rotation of the partition plate 130 by a gear pair or the like. In the example of FIG. 4, the electric switch 500 is turned on when the partition plate 130 is in the initial position, and the electric switch 500 is turned off when the partition plate 130 is not in the initial position. Note that the relationship between the position of the partition plate 130 and the on / off state of the electric switch 500 may be reversed from that in FIG.

  FIG. 5 is a diagram illustrating an example in which a rotation sensor 600 is used as the position detection device. The rotation sensor 600 detects the rotational position of the rotating shaft 123 that rotates integrally with the partition plate 130.

  FIG. 6 is a diagram illustrating an example in which a photoelectric sensor 700 is used as the position detection device. In this case, the wall 127 on the photoelectric sensor 700 side of the storage chamber 120 is transparent so that the output light from the photoelectric sensor 700 and the reflected light of the output light reflected by the partition plate 130 can pass through the storage chamber 120. . In order to facilitate position detection by the photoelectric sensor 700, the area of the surface of the partition plate 130 facing the photoelectric sensor 700 may be increased. Note that the position detection device shown in FIGS. 4 to 6 can also be applied to the partition shown in FIGS.

  In the above-described embodiment, the partition plate 130 is provided with the permanent magnet 126, and the proximity sensor 142 that detects the position of the permanent magnet 126 is provided outside the storage chamber 120. The permanent magnet 126 may be provided outside the storage chamber 120.

It is a schematic diagram which shows the structure of the purge apparatus 10 and the leak inspection apparatus 100 to which this invention was applied. It is a figure which shows an example so that the moving plate 310 which is a pressure difference reaction part may translate in a gas distribution direction. It is a figure which is provided with the fixing | fixed part 400, and shows the example comprised so that the rotating plate 410 which is a part of partition part might rotate. It is a figure which shows the example using the electric switch 500 as a position detection apparatus. It is a figure which shows the example using the rotation sensor 600 as a position detection apparatus. It is a figure which shows the example using the photoelectric sensor 700 as a position detection apparatus.

Explanation of symbols

10: Purge device, 20: Fuel tank, 100: Leak inspection device, 125: Spring (biasing member), 126: Permanent magnet, 130: Partition plate (partition portion, pressure difference reaction portion), 132: Orifice, 142: Magnetic proximity sensor, 150: negative pressure pump, 300: fixed part, 310: moving plate (pressure difference reaction part), 312: orifice, 320: coil spring (biasing member), 400: fixed part, 402: orifice, 410: Rotating plate (pressure difference reaction unit), 500: Electric switch (position detection device), 600: Rotation sensor (position detection device), 700: Photoelectric sensor (position detection device)

Claims (8)

A fuel vapor leak inspection device for inspecting whether or not a leak hole having a predetermined diameter or more is formed in a fuel tank or a purge device that purges fuel vapor generated in the fuel tank into an intake pipe of an engine Because
A pump for transforming the fuel tank and the purge device;
Except for the part where the orifice is formed on the gas flow path through which gas flows when the inside of the fuel tank and the purge device is transformed by the pump, and the orifice is formed. A partition for closing the gas flow path;
A part of or all of the partition part, and a pressure difference reaction part that moves by the pressure difference between the front and the back,
An urging member that urges the pressure difference reaction portion in a direction opposite to the direction of movement due to the pressure difference;
A leak inspection apparatus comprising: a position detection device that detects whether or not the position of the pressure difference reaction part is an initial position when there is no pressure difference before and after. The pressure difference reaction part is rotatable around an axis that is perpendicular to the gas flow direction, and the orifice is formed in the pressure difference reaction part. Leak inspection device. The partition portion has a fixed portion that is immovable with respect to the gas flow path,
The pressure difference reaction part is rotatable around a rotation axis provided in the fixed part perpendicular to the gas flow direction,
The leak inspection apparatus according to claim 1, wherein the orifice is formed in the fixed portion. The partition portion includes a fixed portion that is immovable with respect to the gas flow path,
The pressure difference reaction part can be separated in the gas flow direction with respect to the fixed part, and when there is no pressure difference between the front and the rear, the pressure difference reaction part is urged by the urging member to contact the fixed part without a gap. The leak inspection apparatus according to claim 1, wherein: The position detection device includes a magnet provided in any one of the gas flow pipes constituting the gas flow path in a portion where the pressure difference reaction part and the partition part are provided, and the pressure difference reaction part and The leak inspection apparatus according to claim 1, comprising a magnetic proximity sensor provided on the other side of the gas flow pipe. The position detection device is operatively connected to the pressure difference reaction unit, and is configured to switch between an on-off state when the pressure difference reaction unit is at the initial position and when it is not at the initial position. The leak test apparatus according to claim 1, wherein the leak test apparatus is a leak test apparatus. The leak detection apparatus according to claim 1, wherein the position detection device is a photoelectric sensor that optically detects the position of the pressure difference reaction unit. The leak detection apparatus according to claim 2, wherein the position detection device is a rotation sensor that detects a rotation position of the pressure difference reaction unit.

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