JPS6263279A - Valve box of butterfly type valve - Google Patents

Abstract

PURPOSE:To share compression stress, produced by tightening, by an inner and an outer shell with each other, by a method wherein a valve box is formed in a double structure of an inner and an outer shell, a space is formed between the inner and the outer shell, and the inner and the outer shell are integrally secured to both end parts of the valve box. CONSTITUTION:A valve box 1 is located between the nip formed by flanges 10 of lines on both sides, and is formed with an inner shell 4 and an outer shell 5. The material of inner shell 4 is a cylinder body with a thin section, and a central part forms a cylinder part 6 as it is and serves to limit a flow passage, and both sides are expanded in an S-shape by press processing to form packing containing parts 7. The outer shell 5 is a cylinder body with a thin section made of a steel sheet, and is fitted in the outer periphery of the inner shell, and the both ends are orderly arranged and superposed and secured to each other by butt welding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a valve box for a butterfly valve, particularly to a novel structure of a valve box formed from a metal plate by press working.

[Prior art] In the past, valve bodies for butterfly valves were manufactured by machining finished castings made from ferrous or non-ferrous metals, but in recent years, they have been manufactured using advances in sheet metal press machines to manufacture ferrous or non-ferrous metals. Non-ferrous metal plates are formed by press working, and subsequent mechanical loading is omitted, or the valve box, which guarantees precise dimensions with minimal processing, is produced with great loss. This is a dramatic reduction compared to cast products.

In addition, since the speed is significantly reduced, construction benefits can be obtained when installing the pipe into the pipeline, and since the load on the pipeline is small even during use, there is a great benefit in terms of maintenance.

However, while press-molded butterfly valves have the above advantages, they also have problems that do not occur with cast products due to their small wall thickness.

This point will be explained by showing the connection state of a general butterfly valve in FIG.

In this figure, 1a is a valve box, which is composed of a cylindrical body 6a and a packing housing part 7a with both ends thereof bent at right angles. It is in contact with

Several common circular holes are drilled in the left and right pipe flanges, and the holes are tightened with bolts 28 and nuts 29, and the fitted packing 9a is pressed tightly to achieve water sealing. η It's getting full.

[Problem to be solved by the invention] When this tightening is applied in the right horizontal direction, the stress is concentrated on the bending line l- of the packing housing part 7a, and since the thickness of the molded material is thin, it may cause deformation. There is a risk of damage.

In particular, this part is either pressed out with a press so that it has a larger outer diameter than the cylindrical part 6a, so that the wall thickness is thinner than the original thickness, or a separately molded annular packing housing part is welded and fixed here. Because of this, it is the part of the valve box that tends to be the weakest in terms of strength.

Therefore, the risk of breakage and deformation is further exacerbated.

Incidentally, there have been several attempts to solve this problem in the past, for example, as shown in FIG.
and the packing accommodating portion 7b] - A configuration in which a large number of triangular reinforcing ribs 30 are welded to each other, or the cylindrical body 6G is expanded from the middle toward the outer end in a widening shape as shown in FIG. (Applicant-5 = own earlier application "Structure of Valve Box" Publication of Utility Model Application No. 8577/1983).

The former is a well-known technique, but since the durability against internal pressure varies depending on the location, a large number of ribs are required, reducing work efficiency and making it unsuitable for mass production.

The latter has the effect of being able to withstand compressive stress much better because the load is applied by decomposing the compressive stress into an inclined vector, but since the load acting in the circumferential direction of the pipe due to fluid pressure is proportional to the pipe diameter, it expands toward the end. A large load is placed on the inner wall.

Therefore, when integrally formed using a press, the plate thickness becomes thinner in inverse proportion to the expansion, so the original plate thickness must be selected by calculating in advance the plate thickness that can withstand the increased load, and then calculating the thinning due to processing.

In order to solve the above problems, the present invention has a structure that sufficiently withstands compressive stress even when tightened from the left and right sides for water sealing by interposing it in a conduit, and also withstands internal pressure, and is a highly productive press. The main purpose of this invention is to provide a valve box for a butterfly valve formed by processing.

-〇- [Means for solving the problem] The valve box of the butterfly valve according to the present invention has two parts (one
The inner shell consists of a cylindrical part that limits the flow path, and packing storage parts at both ends whose outer diameter is expanded from the cylindrical part, and the outer shell surrounds the entire outer circumference of the inner shell. The above-mentioned problem was solved by forming a space with the inner shell and the outer shell integrally fixed at both ends of the valve box.

1 Effect] Since the valve box of the track-type valve according to the present invention has a nozzle-like structure, when it is sandwiched between the left and right pipes and tightened from both sides,
The compressive stress applied to the packing housing part is evenly received by the overlapping end surfaces of the inner shell and outer shell that form the end of the valve body, so it is shared between both parts, and the bending line of the inner shell 1
- The burden on the company will be halved.

On the other hand, it is the cylindrical part of the inner shell that receives the internal pressure from the fluid passing through the valve box, and since this part cannot be thinned by expansion processing, it is sufficient to avoid increasing the wall thickness on the outside. Can withstand internal pressure.

In addition, the inner shell's thinner packing accommodating section absorbs the internal pressure in a composite manner by backing it up with the outer shell behind it.

[Example] A preferred embodiment of the present invention is shown in Fig. 1 (partial front view).
The explanation will be given based on FIG. 2 (partial side view) and FIG. 3 (perspective view).

The valve box 1 is sandwiched between flanges 10 and 10 of the left and right pipes, and is formed by an inner shell 4 and an outer shell 5.

The inner shell 4 is made of a thin cylindrical steel plate, and either the center is made into a cylindrical part 6 that serves to limit the flow path, or both sides are expanded into an S-shape by press working to form a packing accommodating part 7,
form 7.

In this embodiment, the S-shape 1 is inclined so that the width W on the outer diameter side of the packing 9 to be accommodated here is larger than the width W2 on the inner diameter side.

The outer shell 5 is a thin-walled cylindrical body made of a steel plate, and is fitted onto the outer periphery of the inner shell, with both ends aligned and fixed together by butt welding.

The valve stem 2 is a shaft member having a square cross section, and is rotatably supported by an upper bearing 12 via an upper bush 11 and by a lower bearing 14 via a lower bush 13, respectively.

A drive portion 15 protrudes above the valve box from the upper bearing of the valve stem 2.
The valve body 2 can be rotated within the valve body 1 by means of a drive means (not shown) such as a spanner, a dedicated lever, or a round handle.

The inner circumferential sides of the upper and lower bushings 11 and 13 are square shaped like the outer circumference of the valve stem 2, and are fixed to the valve stem with a stopper (press fit), and the outer circumferential sides are cylindrical and can freely rotate with the upper and lower bearings 12 and 14. It becomes.

A valve body 3 is attached to the valve stem 2 in a non-rotatable manner within the valve box, and the valve body has a valve plate 16, which is a pair of disc-shaped thin steel plates facing each other and sandwiching the valve stem in the center. , Covering body 1 which is an elastic material such as rubber which overlaps two valve plates and covers the entire outer surface thereof.
Consisting of 7.

Around the valve stem 2, which passes through the cylindrical center of the inner shell that serves as the flow path, a portion of the inner shell is press-worked to provide an upper flat seat 18 and a lower flat seat 19, respectively. Also on the outer peripheral surface around the valve stem of the corresponding valve body 3 are flat seats 20 and 2]
are provided, respectively, so that the valve body and the valve body can be slid in a sealed manner in accordance with the rotation of the valve shaft.

Other 7 langes 22 are locations where driving means for rotating the valve stem are attached, packing 23, split ring 2
4, 25, a retaining ring 26, etc. are attached directly below the flange to seal the valve stem and the upper bearing.

FIG. 4 shows a second embodiment of the present invention, in which the end of the packing accommodating portion 7 of the inner shell is folded back to form a cross-sectional shape, and the end of the outer shell is inserted into this and fixed by welding. FIG. 5 similarly shows the third embodiment, in which the outer shell end is folded back to form a cross-sectional shape, into which the end of the inner shell packing accommodating portion 7 is fitted and fixed by welding.

It goes without saying that components other than the valve body 1 can be replaced using any known technology; for example, the valve stem 2 may be made of a hexagonal material instead of a rectangular material, and the valve body 3 may be replaced as a whole.
Covered in one body! As shown in Figure 6, overlap the two valve plates, make a groove on the outer periphery, and insert the packing ring 2.
7 may be inserted and sealed while operating.

Next, in any actual MfA embodiment of the present invention, the inner shell 4
and the outer shell 5 can be made of different types of metal materials.

This is because both are pressed and molded separately.

There are countless possible combinations of these different materials, but if the inner shell is made of a material that can be press-formed, for example, high-tensile steel and mild steel, stainless steel and mild steel, stainless steel and Monel metal, mild steel and titanium, nickel and copper, etc. Allows a wide range of choices.

[Effects of the Invention] The first effect of the present invention is that both the inner shell and the outer shell share the compressive stress caused by the tightening associated with the insertion of the pipe into the pipe, so that the expansion bending line 1- It is possible to overcome the weak point of thinning due to molding and prevent damage or deformation of the valve body.

In addition, the inner and outer shells can sufficiently withstand the internal pressure passing through the flow path, which solves the technical problem of A'1.

A more detailed inspection reveals that by constructing the valve box with an inner shell and an outer shell, even if these are thin-walled members, the section modulus increases, which causes a T load on the pipe line due to earthquake packing, etc. There is no risk of damage to the valve box even if (bending) is applied.

In addition, the space 8 is formed by surrounding the entire outer periphery of the outer shell or the inner shell, which prevents energy loss due to heat dissipation from high-temperature fluid, prevents personal injury due to high temperatures, or lowers the outside temperature. There is an advantage that there is no need for heat insulation or heat insulation (heating) equipment to prevent exposure of the resulting scum and freezing of the liquid fluid.

In addition, the inner shell is not affected by the outside temperature and follows the temperature of the pipe fluid in the same state as the valve body, so unlike conventional technology, when the outside temperature rises, only the valve body expands and causes a seal failure. There is no risk of problems such as the valve box contracting due to a drop in outside air temperature, resulting in poor opening/closing.

Next, effects specific to the embodiment will be explained.

First, the second claim will be described.

The problem with the prior art is that the cross section of the packing housing portions 7a and 7G in FIGS. 7 and 9 has a width Wal' on the outer diameter side as shown in the figure.
Since the width Wa2' Wc2 on the inner diameter side is larger than WCl or at least the same in both widths, the packings 9a and 9c may be sucked inward by the fluid passing through the valve box, resulting in incomplete Murakami or packing damage. There was a fear that it would happen.

However, in this embodiment, both the inner shells are expanded into an S-shape by press working, and the S-shape is tilted so that the width W1 on the outer diameter side is larger than the width W2 on the inner diameter side, so that the inner shell is expanded from the packing storage part. There was a risk that the packing would deviate and cause the above-mentioned trouble.

The unique effects of claims 4 and 5 are that the end face of the inner shell or outer shell is folded back to form a three-layer structure at the end of the valve box, so that the withstand pressure is further increased and the fit is improved. Therefore, shortening the weld bead length or applying spot welding can reduce welding man-hours and reduce thermal deformation.

Further, the unique effect common to claims 6 to 9 is that, for example, the outer shell is trAi1! 1. It is made of high-strength, high-tensile steel (high-tensile steel), and the inner shell is made of mild steel that is easily plastically deformed, making it easy to carry out the necessary deep drawing.

Another important effect is that an appropriate material can be selected depending on the pipe atmosphere and the properties of the fluid in the pipe.

For example, if the fluid is alkaline and the outside air is acidic, the valve box is constructed by combining an alkali-resistant material for the inner shell and an acid-resistant material for the outer shell.

Corrosion resistant, heat resistant,
Metal plates with special resistance such as wear resistance can be selected as the material.

In each case, if an appropriate mold is prepared, precise molding is possible through press processing, and it can be easily mass-produced at a low price, so the advantages of the conventional press-molded butterfly valve are still maintained. In addition to solving the problems of the prior art, we were able to add a number of secondary 12f features.

[Brief explanation of drawings]

Fig. 1 is a partial front view of the first embodiment, Fig. 2 is a partial side view of the same, Fig. 3 is a partially cutaway perspective view, and Fig. 4 is a partial cutaway view of the second embodiment. The figures are a partial front sectional view of the third embodiment, FIG. 6 is a front partial sectional view showing another embodiment of the valve plate, FIG. 7 (front sectional view), and FIG. 8 (perspective view). ), Figure 9 (front sectional view):, Figure 3 are drawings each showing separate prior art. 1...Valve box 2...Valve stem 3...Valve body 4
...Inner shell 5...Outer shell 6...Cylindrical part 7
...Packing accommodation section 8...Space section 9...
·packing

Claims (1)

[Claims] 1. An annular valve body 1, a valve stem 2 rotatably mounted across the flow path at right angles to the center of the valve body, and sealed on the inner surface of the valve body as the valve stem rotates. This is a butterfly-shaped valve box consisting of a substantially disc-shaped valve body 3 that moves while moving. The outer shell 5 surrounds the entire outer circumference of the inner shell to form a space 8. The valve box of the butterfly valve is characterized in that the shell 4 and the outer shell 5 are integrally fixed at both ends of the valve box. 2. Claim 1 which imposes a limitation that the packing accommodating portion 7 is formed with a substantially “S”-shaped cross section, and that the width W_1 on the outer diameter side of the packing 9 accommodated therein is larger than the width W_2 on the inner diameter side. The valve box of the butterfly valve described. 3. A valve box for a butterfly valve according to claim 1 or 2, wherein the inner shell 4 and the outer shell 5 are substantially horizontally overlapped and fixed at both ends of the valve box. 4. At both ends of the valve box where the inner shell 4 and outer shell 5 are fixed, the end of the inner shell is folded back into a "U" shape, and the outer shell end is inserted and fixed therebetween. A valve box for the butterfly valve according to item 1 or 2. 5. At both ends of the valve box where the inner shell 4 and outer shell 5 are fixed, the end of the outer shell is folded back into a "U" shape, and the end of the inner shell is inserted and fixed between them. A valve box for the butterfly valve according to item 1 or 2. 6. A valve box for a butterfly valve according to claim 1 or 2, wherein the metal material constituting the inner shell 4 and the metal material constituting the outer shell 5 are a combination of different types. 7. A combination in which the inner shell 4 and the outer shell 5 are substantially horizontally overlapped and fixed at both ends of the valve box, and the metal materials forming the inner shell 4 and the metal materials forming the outer shell 5 are different types. A valve box for a butterfly valve according to claim 1 or 2, comprising: 8. At both ends of the valve box where the inner shell 4 and outer shell 5 are fixed, the end of the inner shell is folded back into a "U" shape, and the outer shell end is inserted and fixed between the ends, and the inner shell 4 is fixed. 3. A valve box for a butterfly valve according to claim 1 or 2, wherein the metal material constituting the shell 5 and the metal material constituting the outer shell 5 are different types of combinations. 9. At both ends of the valve box where the inner shell 4 and outer shell 5 are fixed, fold back the ends of the outer shell into a "U" shape, fit the end of the inner shell between the ends, and fix the inner shell 4. 3. A valve box for a butterfly valve according to claim 1 or 2, wherein the metal material constituting the shell 5 and the metal material constituting the outer shell 5 are different types of combinations.