JPS6228352B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention consists of stacking a plurality of thin metal disk-shaped diaphragms, each layer of the diaphragm is brought into close contact with the other, and the internal stress generated during deformation is dispersed to improve the cycle life. The present invention relates to a method for manufacturing a diaphragm in a diaphragm valve.

[Conventional technology and its problems]

As a conventional metal diaphragm valve, JP-A-52-
As shown in Publication No. 135419, a diaphragm used in a diaphragm valve is punched out to the size of the diaphragm using special steel of the required thickness, and then formed into a predetermined dome shape.Next, the required number of dome-shaped diaphragms are stacked, There is a tightening method that seals the inside of the bonnet from fluid by tightening the outer circumference with the bonnet body or diaphragm receiver. However, although this tightening method has the advantage of making it easy to replace the diaphragm, when the diaphragm is installed, disturbances occur between each layer, which creates gaps between the diaphragm layers, dispersing the internal stress applied to the stacked diaphragms. If the diaphragm is not properly compressed, its lifespan may be shortened, and if the diaphragm's compression force is insufficient, it may leak from its sealing surface.

In order to improve the drawbacks of this tightening method, a welding method has been proposed and implemented as shown in Japanese Patent Application Laid-Open No. 107523/1983. Similar to the tightening method, this welding method involves stacking multiple dome-shaped plates, sandwiching the outer annular portion between the bonnet and a ring-shaped diaphragm metal fitting, and welding the outer circumferential surfaces of these three members. This method has the advantage of being able to seal completely, but if the diaphragm layers are not welded to the diaphragm metal fittings in perfect contact, that is, if there are gaps between the diaphragm layers, the diaphragm valve cannot be used. At this time, the internal stress generated in the diaphragm causes each layer to break, significantly reducing its lifespan. However, with this method, it is difficult to bring the diaphragm layers into close contact.

This is because the stacked diaphragms are placed against the bonnet, so it is not possible to press the entire surface along the diaphragm shape, but only the outer periphery of the diaphragm is pressed, so a thin gap is created in the center of the diaphragm. This is because air is distributed separately.

There is also a method of welding multiple stacked metal plates by strongly clamping them together, but although it is possible to weld plates that are thick enough to be welded, it is impossible to directly weld extremely thin plates such as metal plates for diaphragms. be. Particularly in the case of a thin plate, it is impossible to completely seal the parts by simultaneously melting and welding other parts than the welded parts.

[Means for solving problems]

A plurality of metal disks for diaphragms made of extremely thin metal plates with a dome shape in the center are stacked one on top of the other, and a jig is used to form both sides of the metal disks to have the same curvature as the dome shape of the metal disks. Tighten the diaphragm with strong pressure to eliminate air between each layer of the metal disk for the diaphragm and bring them into close contact immediately.While maintaining this state, next, while holding the diaphragm ring on both sides of the annular portion of the outer periphery of the metal disk, tighten the diaphragm. The outer circumferential surfaces of the ring and the metal disk are welded together in a vacuum, thereby making it possible to ensure the close contact between the diaphragm layers, which was impossible with conventional welding methods.

〔Example〕

The method for manufacturing the diaphragm of the present invention will be explained below based on the first embodiment shown in FIG.

1 is a metal disk, which is made by cutting a thin metal plate made of special steel that can be used as a diaphragm into a desired disk shape, and then bending the center part into a dome shape. A predetermined number of sheets are stacked with matching marks aligned, and the dome portion of this multi-layered metal disk 1 is inserted into the jigs 2a and 2 from both sides.
Clamp with strong pressure at b. In this case, the jigs 2a and 2b have the same curvature on the surfaces that contact the dome part of the multilayer metal disk 1 that will become the diaphragm, and the two jigs are strongly clamped to completely eliminate gaps between the metal disk layers. Tighten so that it fits tightly.

Next, diaphragm rings 3, 3 are applied to both sides of the outer circumferential ring portion 1a of this metal disk 1, and a predetermined tightening pressure of the clamping jigs 4, 4 is applied between the two diaphragm rings 3, 3. The outer annular portions of the plurality of stacked metal disks are tightened and held in this state, and the metal disk 1 is held between both diaphragm rings 3, 3 and the diaphragm rings.
The outer peripheral surfaces of the three parts are welded together. Since this welding is performed in a vacuum state, the adhesion of the metal disk layer is further improved. This is because the entire surface of the metal disk is pressed with a jig that matches its shape, and even if the space between the diaphragm plates is not completely removed by the vacuum during welding, the air between the layers of the metal disk is It comes out completely, so it sticks tightly.

Since the diaphragm ring is brought into contact with and welded to the outer periphery of the metal disc in this way, even extremely thin metal discs can be reliably and easily sealed.Moreover, the diaphragm constructed in this way is easily deformed and has a long lifespan. It can be made longer. The diaphragm thus constructed is used by tightening or welding the diaphragm to the bonnet to completely seal the shaft.

Next, a second embodiment shown in FIG. 3 will be described.

Reference numeral 1 denotes metal disks, which are the same as those described in the first embodiment, and the required number of disks are stacked in the same manner. The dome part of this multi-layered metal disk 1 is inserted into the jig 2b from its bulging convex side.
Press the parts together. In this case, the jig 2b has a concave shape with the same curvature on the surface that contacts the convex side surface of the dome part of the multilayer metal disk 1 that will become the diaphragm, and the tip of the other jig 2a facing this has a flexible A diaphragm 5 is provided, hydraulic oil is supplied between the tip of this jig 2a and the diaphragm 5, and by applying a required pressure to this hydraulic oil, the diaphragm 5 is expanded so as to follow the concave side surface of the metal disk 1. The metal disks are strongly pressed between the diaphragm 5 and the concave surface of the jig 2b, so that the stacked metal disks come into close contact with each other.

Next, diaphragm rings 3, 3 are applied to both sides of the outer circumferential ring portion 1a of this metal disk 1, and a predetermined tightening pressure of the clamping jigs 4, 4 is applied between the two diaphragm rings 3, 3. The outer annular portions of the plurality of stacked metal disks are tightened and held in this state, and the metal disk 1 is held between both diaphragm rings 3, 3 and the diaphragm rings.
The outer peripheral surfaces of the three parts are welded together. Since this welding is performed in a vacuum state, the adhesion of the metal disk layer is further improved. This is done by pressing the entire surface of the metal disk along the concave surface of the jig between a jig that matches the shape of the metal disk and a flexible jig diaphragm. Even if pressing with a jig does not completely release the air between the metal disc layers, the air between the metal disc layers will be completely removed, resulting in close contact.

Since the diaphragm ring is brought into contact with and welded to the outer periphery of the metal disk in this way, even extremely thin metal disks can be reliably and easily sealed, and the diaphragm made of the metal disk constructed in this way is easily deformed. And its lifespan can be extended.

In this second embodiment, since the jig diaphragm 5 is provided at the tip of the jig 2a on the side of the dome concave portion of the metal disk, when the metal disk is strongly tightened by the jigs 2a and 2b, the tip surface of the jig 2a is and the diaphragm 5 by applying hydraulic pressure between the diaphragm 5 and the diaphragm 5.
By applying hydraulic pressure between the metal disks, the diaphragm 5 can tighten the disks uniformly and reliably over the entire dome portion along the structure of the concave surface of the metal disk dome, thereby making the tight contact between the metal disks more reliable. .

〔Effect of the invention〕

According to the present invention, a predetermined number of thin metal disks for the diaphragm are stacked one on top of the other, and the dome portion is tightly tightened using a jig whose tip surface matches the curvature of the dome, and then the annular portion on the outer periphery of the dome is tightened. Since the metal disc is sandwiched between the diaphragm rings and welded together in a vacuum, the air between the layers is completely removed without forming any air layers between the metal disc layers. The metal disks are in close contact with each other without any gaps, and when used as a diaphragm, the internal stress generated in the diaphragm is absorbed by the pressure applied to the top diaphragm, and the metal disks are in close contact with each other. Since each layer is individually distributed and supported by all diaphragms, there is no need to generate more stress than necessary on some diaphragms due to the gaps between the layers, which can improve the repeated life of the diaphragm. There are advantages.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing one embodiment of a diaphragm valve, and FIGS. 2 and 3 are explanatory diagrams showing a method of manufacturing the diaphragm of the present invention. 1 is a metal disk, 1a is an annular portion, 2a, 2b are jigs, 3 is a diaphragm ring, 4 is a clamping jig, 5
is the jig diaphragm.

Claims (1)

[Scope of Claims] 1. A plurality of metal disks for diaphragms made of extremely thin metal plates and having a dome shape in the center are stacked on top of each other, and both sides are formed to have the same curvature as the dome shape of the metal disks. Tighten the diaphragm metal disk with strong pressure from both sides using a jig to eliminate air between each layer of the metal disk for the diaphragm so that they fit tightly together without any gaps.While maintaining this state, diaphragm rings are then placed on both sides of the annular portion of the outer periphery of the metal disk. A method for manufacturing a diaphragm for a diaphragm valve, characterized in that the diaphragm ring and the outer peripheral surface of a metal disk are welded together in a vacuum state while strongly clamping the metal disk. 2 A stack of extremely thin metal disks for diaphragms with a dome-shaped center are tightened from both sides of the dome using a jig formed to have the same curvature as the dome, and then the tip of one of the jig is tightened. A jig diaphragm provided on the dome is used to uniformly follow the concave surface of the dome, and the air between the metal disks is eliminated by further tightening with strong pressure, and then both sides of the annular part of the outer periphery of the metal disk are held between diaphragm rings. A method for manufacturing a diaphragm for a diaphragm valve, characterized by welding these three components together under a vacuum condition.