JPH0454423A - Leak inspection device for hollow member - Google Patents

Abstract

PURPOSE:To make a camera observation for a check on an air bubble due to a leak automatically and to improve the accuracy and efficiency of the leak inspection by providing a work clamp which presses a work and and air bubble observation camera above an inspection table so that they can freely be elevated. CONSTITUTION:When a clamp elevation table 13 is put in up-down motion, the air bubble observation camera 16 fitted on its reverse surface is elevated together with the work clamp 15. The work clamp moves down to press the work W placed on the inspection table 2. The camera 16 incorporates a CCD type image sensor to pick up an image of an inspected part of the work W which is entered from a nozzle 18 and inputs the observation image to an image processor 19. In the processor 19, the generation of an air bubble due to the leak of the work W and its generation position are processed and displayed on a CRT 20. Consequently,the inspection time is shortened and the efficiency of the inspection is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a leakage testing device for a hollow member that checks for leakage by observing air bubbles generated from a water entry testing portion of a workpiece.

[Prior art] To check for leaks in hollow members, such as valves, a bubble test is performed by filling water into the test location inside the valve, introducing high-pressure air from below, and checking for air bubbles to form from the water entry test section. It is being said. For this inspection, a special inspection device has been developed that automatically sets the workpiece to the inspection state on the inspection table, but the work to check for air bubbles in the water entry inspection section of the workpiece is performed exclusively by visual observation by the inspector. The current situation is that it depends on the situation.

[Problems to be solved by the invention] However, with the current visual observation, inspection accuracy tends to vary depending on the inspector, and the inspector is forced to stare at the water entry inspection part of the workpiece for a certain period of time each time an inspection is performed. Therefore, it is pointed out that the problem is that it takes time and effort, and inspection efficiency is not improved.

The present invention enables accurate and efficient leakage checking of hollow members by bubble inspection, and also from the viewpoint of promoting labor-saving inspection, the bubble inspection at the water entry inspection section of the workpiece can be automatically performed using a bubble observation camera. To provide a leakage testing device.

[Means for Solving the Problems] The leakage testing device for hollow members according to the present invention includes an inspection table with an open air introduction chamber for introducing high-pressure air, and a workpiece on the inspection table with the air introduction chamber airtightly closed. A workpiece clamp that pressurizes the water is provided, and a bubble observation camera that takes an image of the water entry inspection portion of the workpiece is provided above the inspection table so as to be movable up and down together with the workpiece clamp.

[Function] With the leakage inspection device configured as described above, when the workpiece is placed on the inspection table and then the workpiece clamp is lowered to pressurize the workpiece onto the inspection table, the air introduction chamber of the inspection table can inspect the workpiece. It is set in the inspection state where it is hermetically closed by the section.

At this time, the bubble observation camera simultaneously descends together with the workpiece clamp and is placed on standby at a close position above the inspection table. In this state, when water is injected onto the workpiece inspection section and high pressure air is introduced into the air introduction chamber of the inspection table, if there is a leakage point in the water entry inspection section of the workpiece, air bubbles will rise from the corresponding position. come. Then, bubble observation at this time is automatically performed by a bubble f/ft inspection camera waiting at a nearby position above the workpiece.

[Example] Examples will be described in detail below with illustrations.

FIG. 1 shows an example of the configuration of a leak testing device according to the present invention.

The main body of the apparatus is assembled with an inspection table 2 fixed on a support table 1 and a work clamp mechanism 3 disposed above the inspection table 2 as main components.

The inspection table 2 is formed of a hollow ring member having an air introduction chamber 4 therein, and has an annular mounting surface 5 on its upper surface on which a workpiece W to be subjected to a leakage check is placed. An air introduction chamber 4, which is airtightly closed by the workpiece W during inspection, is opened in the workpiece mounting surface 5.

The inspection table 2 has a shaft part 6 which penetrates the support table 1 and protrudes downward, and high-pressure air is supplied from an air supply source (not shown) to an air introduction hole 7 formed in the shaft part 6. A leading air pipe 8 is connected, and high pressure air is introduced from the air pipe 8 into the air introduction chamber 4 through the air introduction hole 7 of the shaft portion 6. Note that the air pipe 8 is provided with a necessary air valve 21, and a drain pipe provided with a relief valve 22 is branched from the air valve 21.

On the other hand, the work clamp mechanism 3 disposed above the inspection table 2 is mounted on a ceiling stand 10 supported by columns 9.9 erected from the support stand 1. The work clamp mechanism 3 is
The clamp lifting table 13 is equipped with a cylinder 11 vertically fixed on a ceiling stand 10 at a position concentric with the inspection table 2, and a clamp lifting table 13 connected and supported by a cylinder rod 12 hanging from the cylinder 11. Below the rod 14
．． Ring-shaped work clamp 1 supported via 14
5 is attached. And the clamp lifting platform 13
A bubble observation camera 16 is concentrically fixed on the lower surface of the workpiece clamp 1 and the like.

Thus, when the clamp lifting table 13 is moved up and down from the cylinder 11 via the cylinder rod 12, the bubble observation camera 16 attached to the lower surface of the clamp lifting table 13
is raised and lowered together with the workpiece clamp 15, and in the descending state (inspection set state) in which the workpiece clamp 15 airtightly pressurizes the workpiece W placed on the inspection table 2, the bubble observation camera 16 moves close to the workpiece directly above the inspection table. You will be waiting at your location.

The bubble observation camera 16 is configured with a built-in CCD image sensor, for example, and has a high-frequency illumination 17 installed around a light entrance section provided with a condensing lens to illuminate the workpiece inspection section. This camera 16 takes an image of the inspection part of the workpiece W entering water from the nozzle 18 at a position close to the workpiece, and converts the observed image into an image processing device (multi-shape window area comparison processor) 19 attached to the leakage inspection device. Enter.

Then, in the image processing device 19, the presence or absence of bubble generation and the generation position in the water entry inspection section of the workpiece W are arithmetic processed and displayed on the CRT 20 as necessary.

Next, the operation of the present apparatus will be explained using an example in which a leakage test is performed on a butterfly valve shown in FIGS. 2 and 3.

This valve has a mechanism in which a seat ring R is fitted onto the inner circumference of the valve body (■), and the valve body B slides on the inner circumference of the seat ring R and swings to vary the valve opening degree. However, according to this device, when the valve is fully closed, the valve body B
Also, the presence or absence of leakage from the sliding contact surface of the seat ring is checked by a bubble test.

However, the workpiece (valve) W
One cycle of the leakage test will be explained. First, with the clamp lifting table 13 retracted to the upper position shown by the solid line in FIG.
Place it in a concentric position. Next, the work clamp mechanism 3 is operated, the work clamp 15 is lowered to the inspection position shown by the two-dot chain line in FIG. 1, and the work W is pressurized. At this time, the workpiece clamp 15 presses the end face of the workpiece W (valve body ■ and seat ring R) to the mounting surface 5 of the inspection table 2, so that the air introduction chamber 4 of the inspection table 2 is airtightly closed. Become. At this time, as shown in FIG. 2, the bubble observation camera 16 is lowered to a position directly above the workpiece W and is on standby.

After the workpiece W is set to the inspection state in this way, an appropriate amount of water Wa is injected from the nozzle 18 into the inspection part of the workpiece W (above the valve body B), and on the other hand, the water is passed through the air pipe 8 to the inspection table 2.
High pressure air is introduced into the air introduction chamber 4, and a bubble test is carried out for a certain period of time.

At this time, the water entry inspection part of the workpiece W is imaged by the bubble observation camera 16 that is waiting at a position close to the upper part of the water entry inspection part, and as shown in FIGS. 2 and 3, if there is a leakage point in the water entry inspection part of the workpiece W, , bubbles bu rising from the leakage location
b is input into the image of the bubble observation camera 16. and,
The image of the water entry inspection section taken by this camera 16 is
The information is input to the image processing device 19, and the device 19 displays pass or fail based on the presence or absence of air bubbles (leakage) in the workpiece W, and for rejected items, it also displays the location of air bubbles (leakage location). will be displayed in real time. In addition,
For rejected products, the leakage points will be repaired and then re-inspected.

Next, after completing the inspection for a predetermined time, the air valve 21
After switching the switch to stop the introduction of high-pressure air to the air introduction chamber 4, open the relief valve 22 to first exhaust the high-pressure air from the air introduction chamber 4, and then open the valve body B of the workpiece W and inspect it. Drain the water Wa injected into the section. Thereafter, the clamp elevating table 13 is raised and the bubble observation camera 16 is retracted upward together with the workpiece clamp 15. After that, the inspected workpiece W is taken out and the next inspection cycle begins.

Note that the work for attaching and removing the workpiece W to and from the inspection table 2 is automatically performed by handling by a dedicated robot.

With the leakage inspection device configured as described above, air bubbles can be observed in the water entry inspection section of the workpiece W by descending together with the workpiece clamp 15 that pressurizes the workpiece W onto the inspection table 2, and automatically at a close position directly above the workpiece W. Since the bubble observation camera 16 is on standby, inspection errors and subjective variations in inspection accuracy that occur when visual observation is performed are eliminated. Also, work 1
The inspection time for each item is shortened, inspection efficiency is improved, and the leak inspection process can be fully automated to save labor.

In the above embodiment, a butterfly valve was exemplified as an object to be inspected, but the present device is not limited to application to this type of valves, and can be generally used for leak inspection of hollow members. However, depending on the type of work W,
It is necessary to replace the inspection table 2 on which the work W is placed and the work clamp 15 that presses the work W onto the inspection table 2.

[Effects of the Invention] In the leakage inspection device of the present invention, a workpiece clamp that airtightly pressurizes the workpiece to the inspection table and a bubble observation camera are provided above the inspection table so that the bubble observation camera can be moved up and down. Bubble checking can be performed automatically through bubble camera observation, and improvements can be achieved in various aspects such as accuracy, efficiency, and labor saving in leak testing.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of a leak testing device showing one embodiment of the present invention. 2 is an enlarged half-sectional view of the main part of FIG. 1 during a leakage test, and FIG. 3 is a top view of FIG. 2. DESCRIPTION OF SYMBOLS 1... Support stand, 2... Inspection table, 3... Work clamp mechanism, 4... Air introduction chamber, 5... Work placement surface, 8... Air pipe, 10... Ceiling stand, 11... Cylinder, 13... Clamp lifting platform, 15... Work clamp, 16... Bubble observation camera, 17... High frequency illumination, 18... Water injection nozzle, 19... Image processing device , 20...CRT, W...work, Wa...water,
bubble...bubble.

Claims (1)

[Claims] 1. An inspection table with an open air introduction chamber that introduces high-pressure air, and a work clamp that airtightly closes the air introduction chamber and pressurizes the workpiece are installed on the inspection table. A leakage inspection device for a hollow member, characterized in that a bubble observation camera for taking an image of a water entry inspection section is provided so as to be movable up and down together with the work clamp.