JPH0511042U - Long straight pipe air tightness test equipment - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To improve the reliability and workability of the air tightness test for long straight pipes. [Constitution] At least one air supply pipe 3 is provided in a hood 2 enclosing a test body 1 in parallel with a pipe axis 13. The air supply pipe evenly opens the blowing nozzle 4 over the entire length and is connected to the gas cylinder 37 for the detection gas. The air supply pipe can be moved to and from the tube axis freely, and when there are plural air supply tubes, they can be moved so as to keep the distance to the tube axis equal. The above-mentioned elements are combined with the rotating means 5 for the test body, the means 6 for maintaining the inside of the tube being rotated in vacuum, and the means 7 for detecting the intrusion of the detection gas. While rotating, the test body is sprayed with the detection gas under the same conditions. [Effect] Since the entire surface is inspected under the same condition, the reliability is high and the inspection time is remarkably shortened.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  The present invention applies to tubular bodies, especially long straight tubes, such as cast iron tubes, welded steel tubes, non-ferrous or non-metallic. The present invention relates to an air tightness test apparatus for a tube of material.

[0002]

[Prior art]

  Each tubular body has its own defects depending on its manufacturing method and material. Centrifugal cast iron Defects unique to castings may occur in pipes, and defects unique to welded parts may occur in steel pipes. Sometimes When using these tubular bodies as fuel gas pipes for LPG, etc. May cause an explosion accident if a gas leak should occur, regardless of pipe type More stringent checks are needed.   Conventional magnetic flaw detectors and ultrasonic flaw detectors have a small surface length like pinholes. It was difficult to make deep discoveries. To solve this problem, the gas body is used as a sensing medium. Those skilled in the art will understand that it is possible to perform a stricter check by performing an airtight test by This is a well-known technique. However, in a normal barometric pressure test, air leaks are visually detected by workers. Because it is known, there is a possibility that it may be overlooked. It is not perfect for the inspection.   Be sure to use a technology that applies a special gas other than air to the airtight test as the gas body for detection. Is not new, and there are proposals for pressure resistance test methods and equipment using a few gases. It For example, Japanese Patent Publication No. 53-2595 and Japanese Patent Publication No. 56-89040. However, helium gas is used as a detection gas for airtightness tests of long straight pipes. , The structure is large, the efficiency of the test is low, the reliability of the test result is doubtful There was a problem like that.   In order to solve these problems, the applicant of the present invention has a real fairness 2 as shown in FIG. The technology of Japanese Patent No. 49553 was first proposed and put into practice. This technology is shown in the figure In addition, an openable and closable hood 2a for enclosing a long straight pipe test body 1a and The air supply pipe 3a, which is parallel to the tube axis of the test body and is laid horizontally to have almost the same length, is evenly divided into a large number of openings The gas blowing nozzle 4a for detecting Vacuum inside the baffle plate 101 and the tube of the test body arranged side by side freely along the length And a means for detecting the detection gas leaking into the vacuum tube. It consists of

[0003]   During the development of this prior art, defects of 90 ° and 27 were found within a tubular body circumference of 360 °. Experimental results were obtained that the leak detection sensitivity deteriorates when it is close to 0 °. this Since helium gas is light, it easily rises and fills the upper part (near 0 °, 360 °), This is because the detection sensitivity is improved because the area near the lower part (180 °) is directly sprayed. However, as a solution, a baffle plate that can be changed by a drive device in the hood 101 is provided in the longitudinal direction of the tubular body, and the gap between the outer surface of the tubular body and the baffle plate is set to the pipe diameter. Helium gas sprayed from the lower part (180 °) is kept constant regardless of the Make contact more when rising along the outer surface, and detect near 90 ° and 180 ° It was improved by increasing the sensitivity.

[0004]

[Problems to be solved by the device]

  By the action of this baffle plate, the blow-out nozzle blows out directly to the outer peripheral surface of the pipe. Shape the rising air flow while contacting the helium gas not only to the lower part of the specimen but also to the entire outer peripheral surface. It is a fact that the unevenness of detection sensitivity is reduced because it is performed.   However, if the amount of helium gas blown out is reduced, it will still be The problem that there is a large difference in detection sensitivity at each position below has not been solved. Furthermore In addition, from the results of repeated experiments, the detection sensitivity at each position on the circumference of the test body Estimated by the rate, 100% at the lower part (180 °) and 100% at the upper part (0 °, 360 °) 60 to 70%, 30 to 40% in the middle part (90 °, 270 °) It was And this is due to the helium gas passing between the baffle plate and the circumference of the specimen. It was found that the surrounding air was mixed in the ascending airflow. Helium like this Distance between the gas blowing nozzle and each part of the outer peripheral surface of the test piece, and the angle formed with the blowing direction Since there is a difference in contact conditions, it is inevitable that there will be a difference in detection sensitivity. There are still challenges.

[0005]   In order to solve the above-mentioned problems, the present invention uses a detection gas and uses a long straight pipe. The purpose is to provide an airtight test device that maintains a more uniform detection sensitivity for any part. To do.

[0006]

[Means for Solving the Problems]

  The airtightness test apparatus according to the present invention is an openable and closable flap that encloses a long straight tubular test body 1. The hood 2 is supported in the hood so that it can move back and forth in parallel with the tube axis 13 of the test body. At least one air supply pipe 3 that communicates with the outside detection gas cylinder 37, and The gas nozzle 4 for detecting gas, which is opened substantially uniformly over the entire length, and the test body Means 5 for rotating, means 6 for maintaining a vacuum in the test body during the rotation, By means of means 7 for detecting the detection gas that enters the test body, Solved the problem.

[0007]

[Action]

  Since the hood 2 can be opened and closed freely, first open the hood to attach the long straight tubular test body 1. It is carried in and placed on the rotating means 5. Next, close the hood to a sealed state, and The air inside the chamber is sucked by the operation of the vacuum maintaining means 6 outside the hood to maintain the vacuum state. To have. While rotating the test body at a predetermined rotation speed, blow at least one air supply pipe 3 Equally test the entire length of the test piece so that it directly blows from the discharge nozzle 4 to the outer peripheral surface. Inject intellectual gas. The test body keeps a vacuum while rotating, and if it penetrates the test body If there is a defect, the detection gas blown out is sucked into the interior and detected by the detection means 7. The tester is informed of the leak of the test piece.   When the air supply pipe 3 is one, the test is continued until the test body makes one revolution, but when the number is two The test is completed over the entire circumference and the entire length by rotating 180 ° for three and 120 ° for three To do. When there are multiple air supply pipes, set the same conditions for blowing gas to the specimen for all air supply pipes. Needless to say.   With such a configuration, the detection gas of 100% concentration can be applied to any surface of the test body. The air-tightness test can be performed with the same pressure and the same detection sensitivity.

[0008]

【Example】

  An embodiment of the present invention will be described with reference to FIGS.   In FIG. 1, the hood 2 is suspended upward by a drive cylinder 21 connected to the upper side. As it is lifted and opens the device, a long straight tube test transferred in an orbit not shown The body 1 is carried in and placed horizontally on the rolls 51A and 51B which support both ends thereof. This In the case of the figure, the test body is a centrifugal cast iron pipe, one of which is the receiving port 12 and the other of which is the inserting port 11. Is forming. Rolls 51A and 51B are cylinders 52A that support the bottom surface of each. , 52B can be vertically moved up and down, and the pipe axis 13 can be changed even if the pipe diameter of the cast iron pipe changes. Adjust to keep it in place. When the position of the cast iron pipe is determined, suck the air inside the pipe The vacuum maintaining means 6 for making a vacuum state is operated. In the example of this figure, the end of the insertion port 11 of the pipe The surface presses the end surface packing 62 of the pressing base 61 with the pressing cylinder 63, while The end face packing 54 of the pedestal 53 of the rotating means 5 is crimped to the mouth 12, and the packing is sandwiched between both ends. Keep the airtightness in the pipe. The pressing base 61 is rotatable together with the test body 1, and the receiving base 5 3 has a hollow interior, a rotary joint 55, a pipe 56, a vacuum pump 64 and a detector. It is connected to the detection means 7 for the working gas (helium gas). The rotation of the driving machine 57 for rotation The rolling is decelerated and transmitted to the sheath tube 58, and the pedestal 53 fixed to the sheath tube 53, the test body 1, and the pressing table. It rotates together with 61.   Air supply with a large number of blowing nozzles 4 for ejecting helium gas to the outer peripheral surface of the test body The tube 3 is suspended horizontally and horizontally symmetrically with respect to the tube axis 13 of the test body 1. .

[0009]   In FIG. 2, the air supply pipes 3A and 3B are connected to the engaging bosses 32A via the arms 31A and 31B. It is suspended and supported by a screw shaft 33 that horizontally extends across the hood 2 at 32B. On the screw shaft 33 Is a symmetrically engraved male screw in the opposite direction and is screwed into the female screw engraved in the hole of the engaging boss. ing. A sprocket 34 is fixed to one end of the screw shaft 33, and the sprocket of the drive machine 35 is fixed. When the driving machine 35 is operated, the air supply pipes 3A and 3B are simultaneously engaged with each other because they are engaged with the port 36. Distance from the outer peripheral surface of the test body 1 that moves horizontally in opposite directions about the tube axis at high speed Adjust.   FIG. 3 is a cross-sectional plan view of the test body 1 from the blowout nozzles 4A, 4B of the air supply pipe. It is in the state that the detection gas is being ejected toward the outer peripheral surface, and the constant amount from the blowing nozzle. The detection gas diffuses at an angle, and the same conditions are sprayed at all points on the outer peripheral surface. Indicates that   In the case of this embodiment, the test gas is blown while the detection gas is blown from the blow nozzle. If it is rotated 0 °, the entire outer peripheral surface is inspected.

The helium gas used as the detection gas may be a commercially available product housed in the gas cylinder 37, and in this embodiment, the concentration is 95% or more, the discharge pressure is 1.0 to 1.5 kg / cm ² , and the usage amount is 1.0 to 3. It is about 0 liters / test body. If there is helium gas that penetrates the test body 1 and is sucked into the pipe, the gas passes through the pipe 56 and reaches the helium detector 72 to activate the alarm device 73 to notify the inspector of the defect. At the same time, since the amount of gas for detection which the recliner 71 has penetrated is measured, the size of the defect can be estimated. For example, when converted into the diameter of a pinhole, even a defect of about 0.01 to 0.02 mm can be detected. The blower 23 passes through the connecting pipe 22 above the hood 2 in the hood so that the detection gas does not dissipate after the first airtightness test is completed and the detection of the next test body is not affected. Suction and discharge of the detection gas drifting around. Then, the gate valve is opened and closed to introduce air into the test body 1 to release the vacuum. Further, the driving cylinder 21 is operated to open the hood 2, and the pressing cylinder 63 is retracted to release the sealing and restraint of the test body 1 and carry it out of the hood and replace it with the second test body.

[0011]   FIG. 4 is a vertical sectional side view showing another embodiment of the present invention, in which the air supply pipes are 3C, 3D, 3 The three Es are equilateral triangles and surround the tube axis 13 of the test body 1 at equal distances. Is.   In the figure, the air supply pipe 3C is fixed at the upper center of the hood 2, and this air supply pipe is used as the apex. The air supply pipes 3D and 3E are placed at the positions of the two remaining vertices of the equilateral triangle, and the three points are 6 Form an angle of 0 °.   Since the test body 1 varies in size from 1A, 1B, 1C as shown in the figure, supply air The tubes 3D and 3E also need to move while maintaining the relationship described above. Figure shows an example The engaging bosses 32D and 32E are mounted on the mount 24 and are carved in the engaging boss. The female screw is screwed to the screw shafts 33D and 33E to operate the driving machines 35D and 35E, respectively. Therefore, the air supply pipes 3D and 3E move at the same speed along the screw shaft.   The screw shafts 33D and 33E are diagonally symmetrical with keeping an angle of 30 ° with respect to the vertical line. Since it is fixed in the opposite direction, the relationship between the air supply pipe 3C and the equilateral triangle can be maintained by operating the drive machine. The remaining air supply pipes 3D and 3E move. Therefore, it will be adapted to the outer diameter of the test body 1. Move the cylinder 52 up and down to determine the position of the roll 51, and The positions of the air supply pipes 3D and 3E are adjusted so that a space equal to the space between the air supply pipe and the air supply pipe 3C can be maintained. To adjust.   The straight line connecting the air supply pipes 3D and 3E and the pipe shaft 13 is an angle with the axis of the screw shafts 33D and 33E. Since the difference of 30 ° is generated, the ejection directions of the nozzles 4D and 4E are 60 with respect to the vertical line. Keep the angle of ° and fix it on the tip of the screw shaft. As a result, the size of the diameter of the test body 1 is changed. Even if it is made into a nozzle, the nozzles 4C, 4D, and 4E always divide the outer peripheral surface of the test piece into equal parts, and The jetting directions to the opposite sides can also be equal. Therefore, in the case of this example, the test body 1 The airtight state of the entire surface can be detected by rotating the axis by 120 °.   Even if the number of air supply pipes increases, the blowing time also decreases proportionally, so it can be detected compared to the conventional method. We have obtained the results that the amount of used gas hardly increases.

[0012]

[Effect of device]

  As described above, the present invention applies to all outer peripheral surfaces of a long straight pipe under the same conditions for detection. Since the presence of air leaks is detected by spraying the gas, the reliability of the inspection result is dramatically improved. To do. In addition, if the number of air supply pipes is set to multiple, the time required for each inspection is extremely short. The work efficiency of the contraction inspection is significantly improved.   On the other hand, regarding the amount of detection gas used, conventionally, the specific gravity of helium gas and air was simply Compared to the case where only the outer peripheral surface of the test piece was contacted using the rising airflow due to the difference When you slide, the blowing time is short because it blows from a close distance while rotating the test body. Complete.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional side view of the above.

FIG. 3 is a transverse plan view of the above.

FIG. 4 is a vertical sectional side view showing another embodiment of the present invention.

FIG. 5 is a vertical sectional front view showing a conventional technique.

[Explanation of symbols]

1 test body 2 hood 3 air supply pipe 4 blowing nozzle 5 Rotating means 6 Vacuum maintenance means 7 Detection means 13 Pipe axis 31 arms 32 Engaging boss 33 screw shaft 51 rolls

Claims (3)

[Scope of utility model registration request] 1. An openable and closable hood 2 for enclosing a long straight tubular test body 1, and a gas cylinder 3 for detection outside the hood, which is supported in the hood so as to be capable of advancing and retreating in parallel to a pipe axis 13 of the test body.
7, at least one air supply pipe 3 communicating with the air supply pipe 7, a detection gas blowing nozzle 4 which is opened substantially evenly over the entire length of the air supply pipe, a means 5 for rotating the test body, and the rotating body. 1. A long straight tube airtightness test apparatus comprising: a means 6 for maintaining a vacuum inside the test body; and a means 7 for detecting a detection gas that enters the test body in a vacuum. 2. The air supply pipes 3A, 3B according to claim 1, which are suspended symmetrically in parallel with each other so as to sandwich the pipe axis 13 of the test body, and the engagement bosses 32A of the arms 31A, 31B which suspend and support them, respectively.
32B is a screw shaft 33 that is engraved in the left-right direction by a female screw.
A long straight pipe airtightness test device, characterized in that a roll 5 for rotatably supporting the test body is provided below the intermediate point connecting the two air supply pipes so as to be movable up and down. 3. The air supply pipe 3C according to claim 1, wherein the air supply pipe 3C is fixed above the hood, and the two air supply pipes 3D, 3 are movable in the directions of the other two vertices forming an equilateral triangle having the air supply pipe as an apex.
A long straight pipe airtightness test apparatus comprising a roll 51 supporting E and rotatably supporting a test body below the air supply pipe 3C.