Flow resistance setting

Abstract

To provide a compact flow resistance setting device. [Solution] The flow resistance setting device of the present invention comprises a body, a pipe, a pressure plate, and a screw. The body has a groove with a flat bottom and pipe through-holes formed on two opposing sides near the bottom of the groove. The pipe is inserted into the pipe through-hole so as to pass over the bottom of the groove. The pressure plate is positioned to sandwich the pipe between itself and the bottom of the groove. The pipe-side surface of the pressure plate is a convex curved surface in which the distance from the bottom of the groove changes along the longitudinal direction of the pipe. The screw adjusts the distance between the bottom of the groove and the pressure plate.

Description

Technical Field

[0001] The present invention relates to a flow resistance setting tool used when checking the accuracy of a leak tester.

Background Art

[0002] A work (object to be checked for airtightness) attached to a leak tester is required to have a specified airtightness, and a so-called small leak test is performed. In the small leak test, the inside of the work is set to the test pressure in the atmosphere, and it is checked whether the leakage amount per unit time satisfies the specified value by measuring the change in the gas pressure inside the work. Alternatively, a work with an internal atmospheric pressure is placed in a sealed container, the inside of the sealed container is set to the test pressure, and it is checked whether the leakage amount per unit time satisfies the specified value by measuring the change in the gas pressure inside the sealed container.

[0003] A flow resistance setting tool is used to ensure the accuracy of the required leakage amount per unit time. As the flow resistance setting tool, techniques shown in Patent Documents 1 to 3 are known. Note that the flow resistance setting tool may also be called a flow resistance setting nozzle, a leak master, a master nozzle, etc. As leak testers, for example, techniques shown in Patent Documents 4 and 5 are known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0005] P1 is the test pressure, V e Assuming that P0 is the equivalent internal volume (the volume of space in which the gas at the test pressure can exist), Q is the leakage rate per unit time, ΔP is the change in test pressure after t seconds, and P0 is atmospheric pressure, and that the temperature remains constant, the following equation holds.

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[0006] Equivalent internal volume V for each type of workpiece eTo address this, one possible approach is to prepare workpieces with leakage close to the specified value for each type of workpiece. However, obtaining workpieces with no leakage that fully satisfy the specified value (normal workpieces) is easy regardless of the type of workpiece. However, intentionally manufacturing workpieces with small leakage around the specified value (workpieces with subtle leakage) is difficult. This invention was made in view of this situation and aims to provide a small flow resistance setting device that can be attached to a workpiece. [Means for solving the problem]

[0007] The flow resistance setting device of the present invention comprises a body, a pipe, a pressure plate, and a screw. The body has a groove with a flat bottom and pipe through-holes formed on two opposing sides near the bottom of the groove. The pipe is inserted into the pipe through-holes so as to pass over the bottom of the groove. The pressure plate is positioned to sandwich the pipe between itself and the bottom of the groove. The pipe-side surface of the pressure plate is a convex curved surface in which the distance from the bottom of the groove changes along the longitudinal direction of the pipe. The screw adjusts the distance between the bottom of the groove and the pressure plate. [Effects of the Invention]

[0008] According to the flow resistance setting device of the present invention, the pipe is sandwiched between the bottom of the groove and the convex curved surface of the pressure contact plate, allowing the flow resistance setting device to be made compact. Because it is a compact flow resistance setting device, it can also be attached to a workpiece. [Brief explanation of the drawing]

[0009] [Figure 1] Front view of the flow resistance setting device. [Figure 2] Plan view of the body. [Figure 3] Cross-sectional view of the body along line AA. [Figure 4] A side view of the body as seen from direction B. [Figure 5] Three-view drawing of a pressure-welded plate. [Figure 6] Front view of the sealant retainer.

Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail. Components having the same function are denoted by the same reference numerals, and redundant description will be omitted.

Examples

[0011] FIG. 1 shows a front view of the flow resistance setting tool of the present invention. FIG. 2 is a plan view of the body, FIG. 3 is a cross-sectional view of the body taken along line A-A, FIG. 4 is a side view of the body seen from the B direction, FIG. 5 is a three-view drawing of the pressure contact plate, and FIG. 6 is a front view of the seal member retainer. The flow resistance setting tool 10 includes a body 100, a pipe 200, a pressure contact plate 300, and a screw 400.

[0012] The body 100 has a groove 110 whose bottom portion 111 is flat, and pipe through-holes 120 formed in two opposing side surfaces 112 near the bottom portion 111 of the groove 110. The body 100 may be a columnar metal having the longitudinal direction in the direction of the pipe through-holes 120. For example, it may be made of stainless steel. Also, the groove 110 may be formed by cutting. The outer diameter of the body 100 may be about 7 mm and the length may be about 20 mm.

[0013] The pipe 200 is inserted into the pipe through-hole 120 so as to pass over the bottom portion 111 of the groove 110. The pipe 200 may be made of the same material as the body 100. The pipe 200 may be, for example, made of stainless steel with an outer diameter of 0.4 to 0.8 mm, an inner diameter of 0.2 to 0.4 mm, and a length of about 10 mm. The pipe through-hole 120 may have a diameter that allows the pipe 200 to be inserted and has a small gap.

[0014] The flow resistance setting device 10 may also include a sealing member 500 that closes the gap between the pipe through-hole 120 and the pipe 200, and a sealing member retainer 600 that fixes the sealing member 500. For example, an O-ring may be used for the sealing member 500. The sealing member retainer 600 may also include a step 610 for positioning the sealing member 500. The body 100 also has a sealing member hole 140 that houses the sealing member 500 and the sealing member retainer 600. Male threads may be formed on the outer surface of the sealing member retainer 600, and female threads may be formed on the inner surface of the sealing member hole 140.

[0015] The body 100 may also be provided with a mounting hole 150 at one end in the longitudinal direction. A female thread may be formed on the inner surface of the mounting hole 150. A measuring joint can be attached to the mounting hole 150, for example, when measuring the flow rate of the flow resistance setting device 10.

[0016] The pressure plate 300 is positioned to sandwich the pipe 200 between the bottom portion 111 of the groove 110. The pipe-side surface 310 of the pressure plate 300 is a convex curved surface in which the distance from the bottom portion of the groove changes along the longitudinal direction of the pipe. The pressure plate 300 has two holes 320 for screws. The body 100 has two screw holes 130 in the bottom portion 111 of the groove 110 opposite the holes 320. The screws 400 adjust the distance between the bottom portion 111 of the groove 110 and the pressure plate 300. Two screws 400 should also be used. M2 screws should be used for the screws 400. Figure 1 shows an example of a Phillips head pan head screw.

[0017] The flow resistance setting device 10 uses the screw 400 to crush the pipe 200 so that the leakage amount is close to a specified value. Since the leakage amount is set to be very small, it is necessary to crush the pipe 200 to the point where there is almost no gap. On the other hand, if a small screw is used for the screw 400 in order to make the flow resistance setting device 10 smaller, it becomes difficult to apply the force necessary to crush the pipe 200. With the flow resistance setting device 10, the pipe 200 is sandwiched between the bottom portion 111 of the groove 110 and the convex curved surface of the pressure contact plate 300, so the area where stress is applied can be reduced, and even with a small screw, the force necessary to crush the pipe 200 can be applied.

[0018] Furthermore, since the grooves 110 formed in the body 100 can be formed by cutting, processing is possible even if the body 100 is made smaller. Therefore, the flow resistance setting device 10 can be made smaller. Because the flow resistance setting device 10 can be made smaller, it can also be attached to a workpiece. By attaching the flow resistance setting device 10 to a normal workpiece, it is possible to create a workpiece with leakage close to a specified value. Then, by checking and adjusting the amount of leakage using a workpiece with the flow resistance setting device 10 attached, the equivalent internal volume V can be obtained, which is equivalent to when a known leaking workpiece is attached. e This will allow for verification and adjustment. [Explanation of Symbols]

[0019] 10 Flow rate resistance setting tool 100 Body 110 groove 111 bottom part 112 Side 120 Pipe penetration hole 130 Screw hole 140 Seal member hole 150 Mounting hole 200 Pipe 300 pressure welding plate 310 surface 320 holes, 400 screws 500 sealing member 600 sealing member retainer 610 steps

Claims

1. A body having a groove with a flat bottom and pipe through holes formed on two opposing sides near the bottom of the groove, A pipe inserted into the pipe through-hole so as to pass over the bottom portion of the groove, A pressure plate is positioned to sandwich the pipe between the bottom portion of the groove, A screw for adjusting the distance between the bottom of the groove and the pressure plate, A flow resistance setting device equipped with, The surface of the pressure plate facing the pipe is a convex curved surface in which the distance from the bottom portion of the groove changes in the longitudinal direction of the pipe. A flow resistance setting device characterized by the following features.

2. A flow resistance setting device according to claim 1, There are two of the aforementioned screws, The pressure contact plate has two holes for passing the screws through, The body has two screw holes in the bottom portion of the groove opposite the hole. A flow resistance setting device characterized by the following features.

3. A flow resistance setting device according to claim 1, The body is a cylindrical metal with the direction of the pipe through-hole as its longitudinal direction, The groove is formed by cutting. A flow resistance setting device characterized by the following features.

4. A flow resistance setting device according to claim 3, A sealing member that closes the gap between the pipe through hole and the pipe, A seal member retainer for fixing the aforementioned seal member. It also has, The body also has a sealing member hole for housing the sealing member and the sealing member retainer. A flow resistance setting device characterized by the following features.

5. A flow resistance setting device according to claim 3, The body also has a mounting hole at one end in the longitudinal direction. A flow resistance setting device characterized by the following features.

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