JPS5842418B2 - Fluid leak test device - Google Patents

Description

[Detailed Description of the Invention] Explanation of the Summary This invention is applicable to an apparatus that performs a leak test on a mask of an absolute product using each product as a work when mass producing containers that are manufactured by reliably avoiding leakage from gasoline tanks, etc. When both the workpiece and the mask are connected via piping to a leak detection device connected to a pressure fluid source and a test fluid is sealed in both, the fluid temperature sensor installed in both converts the detected temperature into voltage and detects the leak. This invention relates to a fluid leak test device in which the differential pressure detected by the detection device is canceled by a leak measurement circuit, and in particular, a temperature sensor is installed to directly detect the temperature of the enclosed fluid for masking both the workpiece and the mask. The invention relates to a fluid leak test device in which the maximum value of the detected values of each moving part of the interior is detected as a relative temperature difference by an adder, converted to a differential pressure, and canceled from the detected differential pressure by a leak measurement circuit. It is.

As is well known in the prior art, a wide variety of containers are manufactured in various fields, and among them, sealed containers such as gasoline tanks,
Since leaks are absolutely not allowed in pressure vessels, it goes without saying that rigorous and accurate leak tests must be performed during the inspection process.

Moreover, it is desired that the leak test be performed quickly and efficiently since it is necessary to sequentially perform a large amount of work.

Therefore, various types of leak test devices, including those with basic structures, have been developed and proposed, and leak checks based on differential pressure detection have become more accurate.

By the way, from the viewpoint of improving product accuracy and strengthening the safety factor, the accuracy of the leak check is required to be even higher. The effect of differential pressure on leaks can no longer be ignored, and leak test equipment has been developed and used that includes a temperature compensation circuit to eliminate differential pressure errors due to temperature from leaks.

That is, as shown in FIG. 1, a conventional temperature-compensated fluid leak test device 1 uses a predetermined compressed air source 2 as a pressure fluid source.
A master 4 of a completely leak-free product and a workpiece 5 of a leak-tested product are fixed at predetermined positions on the frame using appropriate setting jigs 4' and 5', and each The master 4 is connected via each supply and exhaust pipe 6, 7, and the opening of the master 4 is always sealed with fixed masking jigs 8, 9, 10, 11, while the workpiece 5 is connected to the hydraulic cylinders 12, 13, Masking jig 1 via 14 and 15
The openings are sealed with 6, 17, 1B, and 19, and after the test, the workpiece 5 can be set alternately with the next workpiece 5.

During the leak test, the master 4 and the workpiece 5 are masked, and compressed air is sealed through the leak detection device 3 via the pipes 6 and 7, and the leak test begins.
The ambient temperature of the workpiece 5 is extremely unstable, and in particular, the pressure due to the temperature of the air after pressurization is not constant due to the temperature difference in the coolant covering the surface of the workpiece 5.

Therefore, masking jig 10.1 for master 4 and work 5
Attach brackets 20 and 21 to
, 21, the predetermined temperature sensors 22 and 23 are brought into contact with the surfaces of the master 4 and the workpiece 5, and
The surface temperature of the sensor is measured and leakage measurement errors due to temperature differences are corrected.

By the way, it is known that the measurement error due to the temperature of the near leak amount is approximated to a minute pressure change due to the difference in temperature change per unit time between the master 4 and the workpiece 5, which are filled with air as the measurement medium. , the temperature sensors 22 and 23
The surface temperature of master 4 and work 5 is T8M,'rsw
temperature voltage conversion mechanism 2 via wiring 24°25.
6 and 27 to convert it into a voltage signal, input each signal to the appropriate adder 29 of the temperature compensation circuit 28 and extract it as a differential pressure signal, and send the differential pressure equivalent to the appropriate sensitivity adjuster 30.
The temperature difference is calculated by subtracting a predetermined value from the leak detection signal from the differential pressure detection mechanism 31 in the leak measurement circuit 32 together with the detection signal from the differential pressure detection mechanism 31 of the leak detection device 3. The resulting signal is output and displayed on the meter relay 33 as measurement data.

In the temperature compensation process, as shown in FIG. 3, if we take the time t on the horizontal axis and the measured surface temperature Ts of the master 4 and workpiece 5 on the vertical axis, it is affected by the ambient conditions as described above. The temperature increase due to adiabatic compression immediately after press-fitting does not necessarily appear in the surface temperature Ts, and the adder 29
The temperature difference amount at the leak detection time (t2tx) after a predetermined time has elapsed from □, a'rs, is the difference between the difference between TSM and Tsw at time t1 and the difference between TSM and Tsw at time t2, that is,
Taking it as the absolute temperature difference between the two, as a result, JTs-
JTsM-, a'rsw is measured, and the measured amount is converted into a value equivalent to the differential pressure by the sensitivity adjuster 30, and then subtracted and removed from the detected leakage amount.

Therefore, basically, the effect of the adiabatic compression of the sealed fluid itself is not directly measured, but the absolute temperature difference, not the relative temperature difference, is measured by measuring the surface temperature of the master 4 and workpiece 5, which are affected by the ambient conditions such as the coolant. However, there was a drawback that the temperature of the air enclosed in the measurement medium fluid, which directly affects leakage, was not measured.

In addition, there is a drawback that it takes a long time to pressurize and detect the absolute temperature difference ATsM of the master 4 and the absolute temperature difference a'rsw of the workpiece 5, and in addition, the temperature sensor, especially the There is an inconvenience that skill is required to ensure that the contact state of the sensor 23 is accurate and uniform every time, and that checking is extremely careful.

Purpose of the Invention The purpose of the present invention is to solve the problems of the temperature-compensated fluid leak test device based on the prior art described above, and to solve the problem by disposing a temperature sensor in the masking jig for the mask and the workpiece. The temperature of the fluid is directly detected by directly touching the fluid inside the masking jig, and the maximum value of the temperature inside the mask and workpiece after the start of measurement is detected.The difference is used during measurement to shorten the measurement time and increase accuracy. It is an object of the present invention to provide an excellent fluid leak test device that is capable of detecting leaks in various industries and is useful in the field of use of sealed containers in various industries.

Structure of the Invention In order to solve the above-mentioned problems, the structure of the present invention, which is in accordance with the above-mentioned object and has the gist of the above-mentioned claims, is that the pressure fluid supplied from the leak detection device is sealed in the set mask and the workpiece, and the pressure fluid is sealed in the set mask and the workpiece. Temperature sensors installed in both masking jigs in advance directly detect the temperature state of the sealed fluid after the measurement starts, and the maximum difference in detected temperature is strongly correlated with relative temperature change, which prevents leakage. A technical measure is taken to remove the amount of leakage by converting the amount equivalent to the differential pressure based on the maximum value difference at the time of detection and subtracting it from the leakage detection output.

Embodiment - Configuration Next, one embodiment of the present invention will be described below based on the drawings from FIG. 4 onwards.

Incidentally, parts having the same features as those in FIG. 1.2.3 will be described with the same reference numerals.

Fluid leak test device 1 which constitutes the gist of the invention
As shown in FIG. 4, a master 4 and a workpiece 5 similar to those described above are connected to a leak detection device 3 connected to a compressed air source 2 of a pressure fluid source via piping 6 and 7, so that the former is fixedly connected to the latter. are replaced in sequence so that each masking jig 8, 9,
10, 11 and 16, 17, 18, and 19, which is the same as before.

Therefore, the masking jig 10 for the master 4 and the workpiece 5
, 19 are well-known predetermined temperature sensors 22'.

23' is installed in advance to directly touch the air enclosed in the master 4 and workpiece 5 to detect the temperature of the enclosed air, and is connected to the temperature-voltage conversion mechanism 2 via wiring 24 and 25 as described above.
6.27, the temperature voltage conversion mechanism 26.27
The conversion signal from the fifth circuit provided in the temperature compensation circuit 28'
As shown in the figure, the maximum temperature value is input to the appropriate maximum value holders 34 and 34' to hold the maximum temperature value, and is input to the adder 29', and the sensitivity adjuster 30' connected to the adder 29' Vessel 2
9', and the output thereof is input to the leak measurement circuit 32 together with the detection signal from the differential pressure detection mechanism 31 of the leak detection device 3, and the leak detection signal is converted to the differential pressure equivalent to the maximum temperature value. The minutes are subtracted and sent to the meter relay 33.

The leak detection device 3 has a filter 35, a safety valve 36, a pressure gauge 37, and a pusher switch 38 installed in the compressed air source 2, as shown in detail in FIGS. 6 and 7, and each of the masking jigs and During the press-fitting process for the master 4 and workpiece 5 that have been installed, compressed air is distributed to the detection side three-way valve 39 and the test side three-way valve 40, and the compressed air branched from the three-way valve 39 through the piping 41 is sent to the two-way valve 42. Piping 4 passes through to the three-way valve 43.
4.45.46, and the same symmetrical arrangement of pipes 4
The compressed air branched from 7 passes through a two-way valve 48 and a three-way valve 49.
The pipes 50, 5L52 are filled up to the point where the pressure is equal to the differential pressure detection mechanism 31, and the compressed air branched to the other three-way valve 40 is branched at the three-way valve 43, 49 via the pipe 53. The pipes 6.7 are connected to the master 4 and the workpiece 5 through pipes 54, 55 and throttle valves 56, 57, respectively, and are made to have equal pressures.

Incidentally, the time chart of each process of pressurization P, equilibrium B, detection t, and release O of the three-way valves 39, 40, 43, 49 and the two-way valves 42 and 48 is as shown in FIG.

Embodiment - Operation In the above-described configuration, a workpiece 5 to be tested is set in a setting jig with respect to a completely leak-free master 4 set in a predetermined manner, and a masking jig 16, 17°18.19, and the compressed air is balanced against the differential pressure detection mechanism 31 by connecting the three-way valves 39, 43, 49 and the two-way valves 42, 48 of the leak detection device 3, and the three-way valve 40, 43,
Compressed air is fed to the master 4 and the workpiece 5 at equal pressure through the throttle valves 56 and 57, and the measurement process begins.

At this time, the masking jig 10 for the master 4 and the workpiece 5,
The temperature sensors 22' and 23' installed in the master 4 immediately directly detect the adiabatic compression of the pressurized compressed air, and as shown in FIG. t at the start of measurement along with the temperature TGW of the sealed air in No. 5.

The temperature starts to rise rapidly at tM and reaches the maximum value at 1W, respectively.

During this time, the detected temperatures TGM and TGW are input to the maximum value holder 34 34' via the temperature voltage conversion mechanism 26, 27, and are held at their maximum value at tM, 1W, and the adder 29
' is held as a relative temperature difference ATG.

On the other hand, the differential pressure detection mechanism 31. Master 4, compressed air pressure man rear two-way valve 42.48 according to the above process for workpiece 5;
By switching the three-way valves 43 and 49, the pressure series of both the master 4 and the workpiece 5 to the differential pressure detection mechanism 31, that is, the piping 4
4, 45, 46, 55°7, work 5 and piping 50, 5
2, 51, 54° 6, the master 4 is shifted to an equal pressure balanced state in the equilibrium process B, and detection measurement begins from detection time t1 to t2.

In the detection and measurement process, as described above, the leak detection device 3 enters a state of equal pressure balance, so if there is a leak, the leakage differential pressure is immediately detected by the leak detection device 3, and the leakage measurement circuit 32 The output will be sent to

On the other hand, the maximum value of the temperature of the compressed air pressurized into the master 4 and workpiece 5 from t□ at the start of measurement is the maximum value holder 34.3.
4', the JTG relative temperature difference is converted by the sensitivity regulator 30' into an amount equivalent to the differential pressure by the adder 29', and the constant output C is transmitted to the leak measuring circuit 32 from the detection time t1 to 42 o'clock.

Of course, the transmission data is transmitted from detection time t1 to t2 as described above.
Although it is not a differential pressure signal based on the relative temperature difference between 1 and 2, as described above, the maximum value difference ATG has an extremely strong correlation with the relative temperature change, so there is virtually no influence.

Then, the signal corresponding to the maximum level difference conversion and the leak differential pressure signal sent to the leak measuring circuit 32 are subtracted from the latter by a predetermined adder (not shown), the differential pressure valve due to temperature is removed, and the signal is sent to the meter relay 33. Is displayed.

If the measurement is completed at 42:00, master 4, work 5
The pressurized air is exhausted from the system together with the pipes 7, 25, 6, 54, and 53 by the switching operation of the three-way valves 43, 49.40, and the hydraulic cylinders 12, 13, and 14.15 are disengaged. The masking jigs 16, 17, 18, and 19 are removed from the workpiece 5, one cycle is completed, and the test for the next workpiece 5 is repeated in the same manner as described above.

Other Embodiments It goes without saying that the embodiments of the present invention are not limited to the above-mentioned embodiments. The difference between the changes in TGM and TGW is input to the leakage measuring circuit 32 from the adder 29' and the sensitivity adjuster 30', and is fed back to the maximum value holder 34 and 34' to obtain each temperature T.

Various aspects can be adopted, such as detecting changes in the decrease in MFTGW, predicting the temperature difference JTG at the start of detection t and thereafter, and eliminating leakage errors due to the temperature difference at an early stage.

Of course, if it is possible to lengthen the test time and the test time for the total workpiece 5, it is also possible to detect and subtract the actual temperature difference JTo from detection time t1 to t2.

Furthermore, it goes without saying that the test fluid is not limited to compressed air.

Effects of the Invention As described above, according to the present invention, in a fluid leak test device having a temperature compensation mechanism, the temperature sensor is basically installed inside the masking so that it comes into contact with the inspection fluid sealed in the masking, thereby improving the conventional workpiece and mask Unlike surface temperature measurement, it is possible to directly detect the temperature of the sealed fluid, and therefore, even if there is a significant difference between the surface temperature of the workpiece and mask and the temperature of the internal sealed fluid, temperature compensation can be performed.
While accurately measuring dynamic conditions such as temperature rise due to adiabatic compression in the press-fit state due to internal volume differences based on the route of the sealed fluid, differences in raw material lots of workpieces, and processing errors, it is possible to accurately measure dynamic conditions such as temperature rise due to adiabatic compression in the press-fit state The excellent effect of being able to accurately measure leakage by subtracting the amount equivalent to a minute differential pressure from the actually measured differential pressure is achieved.

In addition, by incorporating the temperature sensor into a masking jig, wear and tear due to interference with other equipment during work can be reduced as much as possible, durability can be improved, and performance can be maintained. There are also some effects.

Furthermore, a measured temperature maximum value holder is interposed between the temperature voltage conversion mechanism of the temperature sensor and the adder, and the maximum value difference of the dynamic temperature measurement values is held as a differential pressure, and the maximum value difference is the relative temperature. By making it possible to subtract from the leak detection value of the leak detection device at the time of detection due to the relationship that has a strong correlation with the difference, it is possible to shorten the stabilization waiting time from pressurization to detection time. This method has the excellent effect of significantly shortening the test time due to the number of tests performed on the workpiece.

Furthermore, by performing temperature compensation by extrapolating the maximum value in this way, the measurement accuracy of the leak test device can be stabilized for a long time, and therefore, the test reliability can also be improved.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram of the entire temperature-compensated fluid leak test device based on the conventional technology, Fig. 2 is an explanatory block diagram of the first temperature compensation circuit, and Fig. 3 is the measurement time and measurement surface of the device shown in Fig. 1. A graph diagram explaining the relationship curve with temperature, FIG. 4 and the following diagrams are diagrams explaining one embodiment of the present invention, FIG. 4 is a schematic diagram for explaining the overall outline, and FIG. FIG. 6 is a detailed circuit diagram of the leak detection device, FIG. 7 is a time chart thereof, and FIG. 8 is a graph explaining the relationship curve between measurement time and measured temperature shown in FIG. 4. 2... Pressure fluid source, 3... Leak detection device, 5... Leak, 4... Mask,
TGM, TGw...Fluid temperature, 22', 23'
... Temperature sensor, 26, 27 ... Temperature voltage conversion mechanism, T, 31 ... Differential pressure detection mechanism, 3
2... Leak measurement circuit, 10, 19...
・Masking jig, 28′...Temperature compensation circuit,
34゜34'...Maximum value holder, 30'...
...sensitivity adjuster, 29/...adder.

Claims (1)

[Claims] 1. A workpiece and a mask are connected via piping to a leak detection device connected to a pressure fluid source, and each sealed fluid temperature sensor set in the workpiece and mask is connected to a temperature-voltage conversion mechanism, and the temperature-voltage conversion mechanism and the In a fluid leak test device in which a differential pressure detection mechanism of the leak detection device is connected to a leak measurement circuit, a fluid temperature sensor is installed in the enclosed fluid contact area of each masking device attached to the workpiece and mask. and connected to the temperature-voltage conversion mechanism, and the temperature-voltage conversion mechanism is connected to a leakage measurement circuit via a temperature compensation circuit, and the temperature-compensation circuit is connected to the temperature-voltage conversion mechanism. A fluid leak test device characterized in that a maximum value holder and a sensitivity adjuster connected to the leak measuring circuit are connected to each other with an adder interposed between them.