JPH07101193B2 - Differential pressure leak tester with self-diagnosis function - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential pressure leak tester with a self-diagnosis function, which is obtained by adding a self-diagnosis function to a differential pressure leak tester.

[0002]

2. Description of the Related Art FIG. 3 shows a schematic structure of a conventional differential pressure type leak tester. In the figure, 1 indicates an air pressure source. The air pressure stored in the air pressure source 1 is taken out by the pressure adjusting valve 2 so as to have a constant pressure and given to the first solenoid valve SV1. The first solenoid valve SV1 has three connection ports A, B, and C. When not energized, the connection ports A-B are cut off, B-C are communicated, and when energized, the connection ports A-B are connected. Are communicated with each other and B-C is disconnected.

The connection port C is open to the atmosphere, and the branch pipe 3 is connected to the connection port B. One of the branch ports of the branch pipe 3 and the other branch port are connected to the subject 4 through the second solenoid valve SV2,
A reference device 5 having the same internal volume as the subject 4 and no leakage is connected through the third solenoid valve SV3. A differential pressure detector 8 is connected between the flow paths 6 and 7 communicating with the subject 4 and the reference device 5, and the detection signal of the differential pressure detector 8 is input to the controller 12 through the amplifier 9 and the AD converter 11. , And is arithmetically processed by the controller 12 and given to the alarm device 13.

That is, the controller 12 can be composed of a microcomputer. As is well known, the microcomputer includes a central processing unit 12A, a ROM 12B for storing programs and the like, and an R for temporarily storing data.
It is composed of an AM 12C, an input port 12D, and an output port 12E. The detection signal of the differential pressure detector 8 is the amplifier 9
Is amplified by the AD converter 11 and converted into a digital signal by the AD converter 11. The differential pressure detection signal converted into a digital signal is taken into the central processing unit 12A through the input port 12D, compared with a preset value, and when the preset value is exceeded, an alarm signal is output from the output port 12E and an alarm device is output. 13 is activated, and an alarm is issued to inform that the subject 4 is defective.

The controller 12 performs the operation of controlling the solenoid valves SV1, SV2, SV3 in addition to the comparison and determination of the differential pressure detection signals. That is, the first solenoid valve SV1 is controlled to be in the energized state at the start of the inspection, and the second solenoid valve SV2 and the third solenoid valve SV3 are controlled to be in the energized state after a predetermined time from that point, and the air pressure is controlled to the subject 4 and the reference device 5. Give to.

That is, the procedure for inspecting whether or not the subject 4 has a leak is performed as follows. In the initial state, the first solenoid valve SV1, the second solenoid valve SV2, and the third solenoid valve S
Both V3 are in a non-energized state. The second solenoid valve SV2 and the third solenoid valve SV3 are controlled to be open when not energized. Therefore, in this state, the subject 4 and the reference device 5 have the first solenoid valve SV1.
It is open to the atmosphere through the connection port C of. The start signal energizes the first solenoid valve SV1. Due to this energization, the first solenoid valve SV1 is disconnected between the connection ports B and C,
Since the connection ports A and B are communicated with each other, air pressure is applied from the pneumatic pressure source 1 to the subject 4 and the reference device 5. The second solenoid valve SV2 and the third solenoid valve S after a certain pressurizing time (about 1 to 2 seconds)
V3 is energized and the flow paths 6 and 7 are shut off. The detection output of the differential pressure detector 8 is electrically reset to zero after a lapse of a certain time from the time when the flow paths 6 and 7 are shut off, and whether or not the differential pressure value reaches a specified value within a predetermined time after the zero reset is performed. It is monitored by the controller 12.

When the differential pressure value does not reach the predetermined value within the predetermined time range, the subject 4 is judged as "no leakage". Further, when the differential pressure value reaches a predetermined value within the range of the predetermined time, the subject 4 is determined to have "leakage", and the alarm device 13 is activated. At the end of the inspection, the first solenoid valve SV1, the second solenoid valve SV2, and the third solenoid valve SV3 are de-energized and returned to the initial state.

[0008]

In the differential pressure type leak tester described above, for example, if the first solenoid valve SV1 becomes defective, and the inspection is performed while the connection ports A and B are not connected to each other despite being energized, Since the controller does not detect the generation of the differential pressure, there is a drawback in that the subject 4 is judged as a non-defective non-defective product.

Further, even if the differential pressure detector 8 becomes defective and the differential pressure is applied, even if the electric signal corresponding to the differential pressure is not output, an erroneous determination of "no leak" is made. There is. Further, even if the controller 12 and the alarm device 13 become defective and the differential pressure signal from the differential pressure detector 8 reaches the specified value or more, even if the inoperative state is continued, all the test objects will show “no leakage”. Is determined.

Therefore, in order to prevent these inconveniences, conventionally, the operation of each unit is individually checked on a regular basis.
However, since the specimen 4 is inspected in a large amount by the flow work, if the above-mentioned defect of the leak tester occurs during the inspection, the inspection is performed after the defect occurs and the inspection is judged to be a good product. Defective products with leakage will be mixed into the sample, and the reliability of the test will be significantly reduced.

According to the present invention, a self-diagnosis function is provided for automatically making a self-diagnosis of whether or not a leak tester is normal for each one of the test objects, and when the leak tester becomes defective, the state can be immediately alarmed. A pressure leak tester is provided.

[0012]

According to the present invention, there is provided a first solenoid valve for taking out the pressure of an air pressure source adjusted to a constant pressure value, and a branch pipe for bifurcating the air pressure taken out by the first solenoid valve. a second solenoid valve and the third solenoid valve provided in the two flow paths which are branched in the branch pipe, the subject and leakage of air pressure is provided to be withdrawn through the second solenoid valve and the third solenoid valve There is no reference unit, a differential pressure detector that detects changes in the air pressure applied to the subject and the pressure applied to the reference unit, and that the detection output of this differential pressure detector has reached a predetermined value or more. In a differential pressure type leak tester constituted by an alarm device for outputting an alarm, a control means for performing control to open the first electromagnetic valve with either one of the second electromagnetic valve and the third electromagnetic valve closed at the start of inspection. , the second electromagnetic valve and the third solenoid by the control means Determined that either one provided with determining means for determining whether the alarm device is activated while being controlled in a closed, are normal differential pressure leak tester by the determination means detects the alarm operation of the It is configured to do.

As described above, when the first solenoid valve is controlled to be open in a state in which one of the second solenoid valve and the third solenoid valve is controlled to be closed for a short time at the start of the inspection, the alarm device is activated. Then, it is possible to determine that the leak tester is normal.
In other words, if the first solenoid valve is controlled to open while either the second solenoid valve or the third solenoid valve is closed, the air will only flow to the subject or the reference device if the first solenoid valve is operating normally. Given.

Therefore, in this state, if the differential pressure detector is normal and the controller and alarm are normal, the alarm is activated.
Therefore, if this alarm does not operate, it can be determined that any one of the three is defective.

[0015]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, portions corresponding to those in FIG. 3 are designated by the same reference numerals. According to the present invention, the second solenoid valve SV2 and
A means for controlling one of the third solenoid valves SV3 to be in a closed state to control the first solenoid valve SV1 to be open and a determination means for determining whether or not the alarm device 13 operates in this state are provided.

At the start of the inspection, the second solenoid valve SV2 or the third solenoid valve SV2
The controller 12 may be configured to control either one of the solenoid valves SV3 to be closed and to control the first solenoid valve SV1 to be open in this state. That is, the program stored in the ROM 12B of the microcomputer that constitutes the controller 12 includes, for example, the second solenoid valve S at the timing of starting the inspection.
A step of controlling V2 to be closed for a short time and a step of determining whether or not an activation signal is output to the alarm device 13 are added.

When the activation signal is not transmitted to the alarm device 13, the activation signal is transmitted to the alarm device 14 provided separately, and the activation of the alarm device 14 causes the abnormality of the differential pressure type leak tester to be displayed. FIG. 2 shows another embodiment of the present invention. In this embodiment, the case where the present invention is applied to a differential pressure type leak tester when the volumes of the subject 4 and the reference device 5 are large is shown.

That is, in this embodiment, the fourth solenoid valve SV4 is arranged between the second solenoid valve SV2 and the subject 4, and
A fifth solenoid valve SV5 is provided between the third solenoid valve SV3 and the reference unit 5.
To place. These fourth solenoid valve SV4 and fifth solenoid valve SV
5 is a three-way valve, and connects the connection port C of the three-way valve to one connection port B of the first solenoid valve SV1. First solenoid valve SV
The other connection port A of 1 is connected to the output side of the regulating valve 2 and is directly connected between the regulating valve 2 and the branch pipe 3.

Here, the flow passages 15 to 17 passing through the first solenoid valve SV1 are generally called bypasses and use pipes having a diameter larger than that of pipes used for other flow passages. At the start of the inspection, the first solenoid valve SV1 is made to communicate between the connection ports A and B and the flow path 1
Air pressure is applied to the subject 4 and the reference device 5 through 5, 16 and 17. In this way, the subject 4
Then, a large amount of air is poured into the reference device 5 in a short time to increase the pressure inside the subject 4 and the reference device 5.

When the internal pressures of the subject 4 and the reference device 5 increase to a predetermined pressure, the fourth solenoid valve SV4 and the fifth solenoid valve SV5 are switched to a state in which the connection ports A and B are energized. At this time the second
Since the solenoid valve SV2 and the third solenoid valve SV3 are left open, air pressure is sent to the subject 4 and the reference device 5 through the second solenoid valve SV2 and the third solenoid valve SV3 in this state.

The second solenoid valves SV2 and SV3 are closed at the timing when a predetermined air pressure is accumulated in the subject 4 and the reference device 5,
In this state, it is monitored whether a differential pressure is generated. When no differential pressure is generated, the subject 4 is determined to be a non-defective non-defective product.
Here, in the present invention, for example, when the air pressure is sent to the subject 4 and the reference device 5 through the bypass to the state where the air is sent through the second solenoid valve SV2 and the third solenoid valve SV3, for example, the second solenoid valve The SV2 is switched to the closed state for a short time to temporarily shut off the air sent to the subject 4.

A differential pressure is generated by this interruption, so that a differential pressure signal is output if the differential pressure detector 8 is normal. On the other hand, if the controller 12 is operating normally, a start signal is output to the alarm device 13. Therefore, when the controller 12 itself detects that the activation signal is output to the alarm device 13, it is determined that the inspection device is operating normally, and the inspection is continued.

At the end of the inspection, the fourth solenoid valve SV4 and the fifth solenoid valve SV4
The solenoid valve SV5 and the first solenoid valve SV1 are switched to a state in which the connection ports BC are communicated with each other. Therefore, the subject 4 and the reference device 5
The air accumulated in is discharged to the atmosphere through the bypass. That is, it can be released to the atmosphere in a short time. Further, by using the bypass as in this embodiment, the exhaust gas output from the subject 4 and the reference device 5 does not pass through the portion including the differential pressure detector 8 especially at the end of the inspection. Therefore, even when the subject 4 contains water, oil, etc., water, oil, etc. do not flow into the differential pressure detector 8, so that the subject 4 can be inspected even after the cleaning process.

[0024]

As described above, according to the present invention, the first solenoid valve SV1 and the second solenoid valve SV2 are inoperable, the differential pressure detector 8 does not detect the differential pressure, and the alarm device is provided. It is possible to detect all the states in which 13 does not operate, and it is possible to provide a highly reliable leak tester.

The self-diagnosis time is not so long as the product inspection time becomes long because the second solenoid valve SV2 is controlled to be closed for a short time of about 0.5 seconds.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a system diagram showing a modified embodiment of the present invention.

FIG. 3 is a system diagram for explaining a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air pressure source 2 Pressure control valve 3 Branch pipe 4 Test object 5 Reference device 6,7 Flow path 8 Differential pressure detector 9 Amplifier 11 AD converter 12 Controller 13 Test device alarm device 14 Test device alarm device 15,16,17 Bypass SV1 1st solenoid valve SV2 2nd solenoid valve SV3 3rd solenoid valve SV4 4th solenoid valve SV5 5th solenoid valve

Claims (2)

[Claims] 1. A first electromagnetic valve for taking out the pressure of an air pressure source adjusted to a constant pressure value, a branch pipe for bifurcating the air pressure taken out by the first electromagnetic valve, and a branch pipe for branching by this branch pipe. The second solenoid valve and the third solenoid valve provided in the two flow paths, the test subject to which the air pressure taken out through the second solenoid valve and the third solenoid valve is applied, and the internal volume equivalent to the test subject. A leak-free reference device, a differential pressure detector that detects changes in the air pressure applied to the subject and the pressure applied to the reference device, and that the detection output of this differential pressure detector has exceeded a specified value. In a differential pressure type leak tester configured to include an alarm device that detects and outputs an alarm, one of the second solenoid valve and the third solenoid valve is provided before the start of inspection.
And control means for controlling the first electromagnetic valve while the control to close to open towards the second solenoid valve and the third solenoid by the control means
The differential pressure type leak tester is provided with judging means for judging whether or not the alarm device is activated in the state where one of the valves is controlled to be closed, and the judging means detects the alarm operation of the alarm device. A differential pressure type leak tester with a self-diagnosis function that is configured to determine that the normal operation is performed. 2. A first electromagnetic valve for taking out the pressure of an air pressure source adjusted to a constant pressure value, a branch pipe for branching the pressure of the air pressure source into two, and two branch pipes divided by this branch pipe. A second solenoid valve and a third solenoid valve provided in the flow path, and a fourth solenoid valve and a fifth solenoid valve through which the pressure of the pneumatic pressure source is applied to each one connection port through the second solenoid valve and the third solenoid valve. A solenoid valve, a subject and a reference device to which the pressure of the air pressure source is applied through the fourth solenoid valve and the fifth solenoid valve, and one of the fourth solenoid valve and the fifth solenoid valve through the first solenoid valve. A differential pressure connected between a bypass for applying the pressure of the air pressure source to one connection port, and a connection point between the second solenoid valve and the fourth solenoid valve and a connection point between the third solenoid valve and the fifth solenoid valve. A detector is provided, and when a pressure is applied to the subject through the bypass and the fourth solenoid valve from the first solenoid valve at the start of the inspection. In both cases, pressure is applied to the reference device from the first solenoid valve through the bypass and the fifth solenoid valve, and from this state, the first solenoid valve is closed to close the bypass, and the subject and the subject are passed through the second solenoid valve and the third solenoid valve. Air pressure is applied to the reference device, then the second solenoid valve and the third solenoid valve are closed, and the presence or absence of leakage of the subject is inspected depending on whether or not the differential pressure detection signal is output from the differential pressure detector. In the differential pressure type leak tester described above, the state in which the air pressure is applied to the subject and the reference device from the bypass is switched to the state in which the air pressure is applied to the subject and the reference device through the second solenoid valve and the third solenoid valve. A differential pressure type leak tester with a self-diagnosis function, which is configured to control either one of the second solenoid valve and the third solenoid valve to be closed for a short time and forcibly apply a differential pressure to the differential pressure detector for self-diagnosis.