JPS6322251B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for testing the leakage of thin plates of a plate heat exchanger in which a heat exchange fluid is forced to flow between a large number of parallel thin plates for heat exchange. This method provides simplicity, accuracy, eliminates the need for post-processing after testing, and significantly improves overall workability.

In conventional heat exchangers, in which a large number of plates are arranged close to each other in parallel and heat is exchanged by alternately passing a heat exchange fluid between each plate, if there are minute holes in the plates, there is a risk of serious accidents. Because of this, each plate leaks and must be tested. Therefore, conventionally, a test method in which a colored liquid is applied to one side of the plate and left as is to detect whether the colored liquid oozes out to the other side has been generally known and has not been put into practical use. (referred to as the color check method). However, in the above-mentioned color check method, not only is it necessary to remove the gasket on a trial basis, but there is also the risk of damage due to the application of the colored liquid, the leaving time for the colored liquid to ooze out, the washing of the colored liquid, and the residual coloring liquid. And it would take 40 to 50 minutes to test one plate.
There was a problem in that the time, effort, and cost required to test for leaks was large.

However, in this invention, a liquid is sealed in an airtight space formed by a transparent plate and a plate, and the pressure of this liquid is reduced. Therefore, if the plate has minute holes, small bubbles will enter the liquid, so it is extremely easy to do so. This method solves the problems of the conventional method, such as being able to detect the gas and performing the test very easily and in a short time (less than 5 minutes) without removing the gasket.

That is, the present invention will be described with reference to the embodiments shown in FIGS. 1 and 2. A packing 4 to be brought into contact with a gasket 3 of a plate 2 to be tested is attached and fixed to one side of a transparent plate 1 in an annular shape. The packing 4 and the gasket 3 of the plate 2 are brought into contact with each other, temporarily secured (for example, by using a clamping device), and the through holes 5, 5a, 5b, and 5c at the four corners of the plate 2 are used for supply and discharge during heat exchange. pores). In this case, the through holes 5, 5a,
A water supply pipe 6 and a drainage pipe 7 are connected to the closing lids 5b and 5c, respectively. The drainage pipe 7 is connected to a lower part of a drainage tank 8, an exhaust pipe 9 is connected to an upper part of the drainage tank 8, and the exhaust pipe 9 is connected to a vacuum pump 12. In the figure, 10 and 11 are valves installed in the water supply pipe and the drain pipe.
In the embodiment described above, when the vacuum pump 12 is driven and the valves 10 and 11 are opened, the water in the open water tank 13 is sucked up as shown by the arrow 14, and is transferred to the transparent plate 1 and the plate 2 through the water supply pipe 6. It rises through the gap 15 as indicated by the arrow 16 (in FIG. 2), passes through the drain pipe 7, and finally reaches the drain tank 8. Then, the valve 10 is closed, and the space inside the drain tank 8 is reduced to a pressure of 200 mmHg or more by the vacuum pump 10.
If the pressure is maintained at 300 mmHg, the water in the gap 15 will also be under reduced pressure.

Therefore, if the plate 2 has micro holes, air will enter the water through the holes and rise as bubbles, and the tester can determine whether the plate is good or not by checking whether air bubbles have entered from the transparent plate side. can be known immediately. In the embodiment described above, the supply and drainage holes of the plate were used as water supply and drainage holes, but it is also possible to provide water supply and drainage equipment in advance on the transparent plate side and use the plate only to block the water supply and drainage holes.

Although water was used as the liquid in the above embodiments, the liquid is not limited to water. Further, the transparent plate is not limited to a glass plate, and for example, an acrylic resin plate or other transparent synthetic resin can be used.

That is, according to the present invention, the plates are arranged side by side with a predetermined gap maintained between the transparent plate, and the liquid is sealed in the gap and the pressure is reduced. Since air bubbles enter the inside, the presence or absence of micropores can be detected very easily and immediately.

Therefore, the plate can be tested with the gasket attached, and if a harmless liquid is used, there is no need for post-treatment of the plate, resulting in excellent workability and safety. Furthermore, unlike color checks, operations such as applying and removing colored liquids are not necessary, and the testing time for one plate can be significantly shortened.

[Brief explanation of the drawing]

FIG. 1 is a front view of an apparatus used to carry out the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is an enlarged partially omitted plan view showing an example of a plate. 1: transparent plate, 2... plate, 3... gasket,
4...Packing, 6...Water supply pipe, 7...Drainage pipe, 8...Drainage tank.

Claims (1)

[Scope of Claims] 1. Plates to be tested are airtightly arranged side by side on one side of a transparent plate with a liquid sealing gap maintained and all four circumferences closed, liquid is sealed in the gap, and the liquid is sealed in the liquid. A method for testing plate leakage in a plate heat exchanger, characterized in that plate leakage is detected by reducing the applied pressure to less than atmospheric pressure and seeing through the intrusion of air from the test plate into the liquid. 2. A method for testing plate leakage in a plate heat exchanger according to claim 1, using water as the liquid. 3. A method for testing plate leakage in a plate heat exchanger according to claim 1, wherein the reduced pressure is 200 mm to 300 mm of mercury. 4. A method for testing plate leakage in a plate heat exchanger according to claim 1, in which the transparent plate is a glass plate.