JP2002527277A - Synthetic resin shut-off valve and method of manufacturing the same - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention relates to a method for producing a shut-off valve for a conduit, comprising a synthetic resin case (1) having two connecting short tubes (2). The shut-off element (3), which can be adjusted between the flow position and the shut-off position via the operating unit, is supported in the housing by at least a bearing ring (4) and a sealing ring (5). The inner part with the shut-off element (3) and the bearings and the sealing rings (3, 4) is pre-assembled and injection-molded with synthetic resin using an adhesive to form the case (1). To be covered. The method according to the invention for providing an economically manufacturable and leak-free shut-off valve comprises the steps of: a) in the area of the insert (6), substantially corresponding to the external shape of the insert (6) and the internal shape of the case (1). A synthetic resin molded part is formed by injection molding, and b) the synthetic resin of the molded part formed in method step a) is welded and connected to the material of the insert (6), and at the same time the insert (6) is formed. Injection molding of the resin on or in the molded part, c) shut-off consisting of valve ball (3), bearing ring (4), seal ring (5), bearing bush (8) and insert (6) and molded part Assembling the inner part of the valve, d) welding the synthetic resin of the molded part forming at least part of the internal shape of the case (1) and the material of the case (1), simultaneously with the method step c) The preassembled inner portion, characterized by coating the synthetic resin by injection molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention is characterized in that the case is made of synthetic resin and has two connecting short pipes, and a shut-off element adjustable between a flow position and a shut-off position via an operation unit is provided in the case at least with the bearing ring. The inner part, supported by the sealing ring and provided with the blocking element and the bearing and the sealing ring, is coated by injection molding a synthetic resin using an adhesive to form a case, in a pre-assembled state. A method for making a conduit shutoff valve. The invention further relates to a shut-off valve made by this method.

[0002] Such a method for producing a shut-off valve is known, for example, from DE-A 44 42 797. In the case of this known method,
In the first method step, first the ball, a part of the switching shaft and the lower part of the bearing pin are covered by injection molding with a plastic covering. In a subsequent working step, an elastic insert is arranged between the flange areas on the outer surface of the synthetic resin cover produced in the first step, and in a subsequent working step on the cover with the elastic insert. The case is formed by injection molding a synthetic resin. This method for making a plastic case for a shut-off valve is very cumbersome. This is because the two-part valve case must be made of synthetic resin. The resilient insert used serves to separate the inner cover from the outer valve case. On the other hand, outside the area of the elastic insert, the two plastics of the inner cover and the outer valve case are integrally connected to each other. In particular, due to the formation of a two-part valve case with an inner cover and an outer valve case, this known method cannot be used economically.

Another method for manufacturing a ball valve with a synthetic resin case is disclosed in EP 0
This is known from U.S. Pat. In the case of this known method, in order to form a synthetic resin case, the pre-assembled inner part is inserted into an injection mold which, in the pre-assembled state, produces the outer shape of the case and the flow hole of the connecting short pipe. And
Subsequently, the periphery is covered with a synthetic resin by injection molding. Such fabrication of a synthetic resin case, in which the entire valve is divided into an outer part and an inner part, has proved effective in practice. By dividing the pre-assembled inner part and the injection-molded outer part, when the case formed in the injection mold is cooled, relative shrinkage of the two case parts occurs, and the case is formed radially inward. Shrinkage is prevented. Thereby,
The valve ball gets stuck in the case and does not move.

The shut-off valves produced in this way are closed, especially when used in conduits with large-diameter connecting stubs and in conduits with high conveying pressures, in particular when used as gas shut-off valves. Despite the shutoff valve, the medium to be shut off is forced between the inner part and the outer part, that is, between the outer surface of the shutoff element and the bearing ring and the seal ring and the inner surface of the synthetic resin case, Leakage of the shut-off valve can actually occur. Such leaks should always be avoided, especially when using valves to shut off gas lines.

[0005] Starting from now, the problem underlying the present invention is that the medium to be shut off does not pass between the inner and outer parts of the valve, so that it can be manufactured more simply and at lower cost. The object of the present invention is to improve a method for manufacturing a shut-off valve for a conduit having a synthetic resin case. It is a further object of the present invention to provide a shut-off valve made according to this method.

[0006] A methodical solution to this problem consists of: a) forming by injection molding a molded part made of synthetic resin, which in the area of the insert substantially matches the outer shape of the insert and the inner shape of the case, b) method step a) C) welding and joining the synthetic resin of the molded part formed in the above step and the material of the insert, and simultaneously injection molding the synthetic resin forming the insert on or in the molded part; c) valve balls, bearing rings, seal rings Assembling the inner part of the shut-off valve consisting of the bearing bush and the insert and the molded part; d) simultaneously welding and joining the synthetic resin of the molded part and the material of the case, which form at least part of the internal shape of the case, simultaneously with the method step c. ) Is covered by injection-molding a synthetic resin.

In the method according to the invention, the adhesive used to connect the inner and outer parts of the shut-off valve is at the same time, in the area of the insert, as a molded part for the outer shape of the insert and the inner shape of the case. Work. The molded plastic part produced in the first method step is melted by the injection-molded synthetic resin during the subsequent injection molding coating to form the insert and the valve case, respectively. A material-integral welding connection occurs between the insert and between the molded part and the valve case.

With this material-integrated connection between the inner part and the inner surface of the case (outer part)
Leaks described in the state of the art are reliably avoided.

In a practical embodiment of the invention, a thermoplastic synthetic resin is used as the synthetic resin for the molded part. At that time, the thermoplastic synthetic resin shifts to a plastic state and a fluid state by heat generated when the inner part is injection-molded with the synthetic resin to cover the circumference, and the outer part of the inner part and the inner part of the outer part are transformed into a plastic state and a flow state. It fits very well and achieves welding of both parts.

In a preferred embodiment of the present invention, a sticky copolymer is used as a synthetic resin for the molded part. The cohesive copolymer is very well linked with other synthetic resins, especially polyethylene, in the proper finishing, and when the synthetic resin is directly injection molded on the cohesive copolymer, Is melted and the two synthetic resins are welded and connected. Since polyethylene is used in particular as a synthetic resin for the valve case, sticky copolymers are very suitable as adhesives.

The conduit shut-off valve according to the present invention manufactured according to the above-described method is such that the inner part and at least a part of the case (outer part) are integrally formed of material through a molded part injection-molded with synthetic resin. It is characterized by being connected to each other. Only by connecting the inner part of the shut-off valve and the outer part of the shut-off valve forming the synthetic resin case in a material-integral manner according to the invention, it is possible to prevent leakage inside the shut-off valve. The leak is that the medium blocked by the shut-off valve passes between the outer surface of the inner part and the inner surface of the outer part. Furthermore, the static state of the entire valve is continuously improved by a material-integrated connection between the inner part and the plastic cover.

The invention furthermore provides in the shut-off valve according to the invention with an insert for connecting the bearing rings to one another an additional anchoring point for a material-integral connection between the case (outer part) and the inner part. To form, it is proposed that a number of notches are formed in the insert. Upon melting of the injection-molded molded part, which acts as an adhesive, the adhesive enters into the cutouts of the insert, whereby it is fixed in the insert in a form-complementary manner. Thus, in addition to a material-integrated connection made by welding, a shape-complementary connection is provided.

[0013] Other features and advantages of the invention will be apparent from the following description of the figures. In the figure, a longitudinal section of a ball valve is exemplarily shown.

The ball valve shown in the embodiment has a case 1 made of synthetic resin, especially polyethylene. In this case, two connecting short tubes 2 facing in opposite directions are integrally formed. This connecting stub 2 serves to connect the ball valve to a conduit, not shown, also made of synthetic resin. The case 1 may have a threaded flange at the end of the connecting short tube 2.

A valve ball 3 serving as a shutoff element is arranged inside the case 1. This valve ball has a flow hole 3a. This flow hole is a flow hole 2a of the connecting short pipe 2.
Matches. The valve ball 3 is supported by two bearing rings 4. The bearing rings are each provided with a sealing ring 5 for sealing against the valve ball 3.
It has.

The bearing rings 4 are furthermore connected to one another at the outer peripheral surface by ring-shaped inserts 6. This connection can be made, for example, by gluing or welding. In the figure, a weld seam is shown as an example.

A switching shaft 7 is provided in the case 1 so as to be able to rotate the valve ball 3 whose flow position is shown in the figure for the purpose of narrowing or blocking the flow hole 2a. This switching shaft is rotatably supported in the bearing bush 8. The switching shaft 7 is engaged with a corresponding recess of the valve ball 3 by a connecting member 7a. Thereby, the valve ball 3 is rotatable by the switching shaft 7 between the circulation position and the shut-off position. For this purpose, a square portion 7b or a polygonal portion is formed at the outer end of the switching shaft 7. An operating unit other than the valve ball drive shown can be used to operate the shut-off element. For example, a shut-off element formed as a valve ball or a tapered slide valve can be operated mechanically via an electric, pneumatic or hydraulic drive. In the case of the illustrated embodiment, the switching dome 9 having the wrench surface 9a is mounted on the square portion 7b of the switching shaft 7. The switching dome is fixed to the switching shaft 7 by a screw 9b so as not to rotate. The end of the switching dome 9 inserted into the case 1 is
And is relatively rotatable, and is sealed by a seal 10.

A bearing bush 8 for supporting the switching shaft 7 is arranged in a cutout of the ring-shaped insert 6. In the embodiment shown, the bearing bush 8 and the insert 6 are welded together. In this embodiment, two ring seals 11 are provided to seal the switching shaft 7 with respect to the bearing bush 8.

Depending on the intended use, the bearing ring 4, the valve ball 3, the insert 6 and the bearing bush 8 can be made of gunmetal, brass, special steel or synthetic resin, in particular glass fiber reinforced synthetic resin or polypropylene. If the components described above are connectable to one another, different materials or different material combinations can be used for the components. For the seal 5, the ring seal 11 and the seal 10, in particular nitrile butyl rubber is used. The switching shaft 7 can likewise be made of a suitable material such as, for example, gunmetal, brass, special steel or synthetic resin.

To produce the illustrated ball valve, in a first method step, a molded part is produced by injection molding from a synthetic resin, preferably a sticky copolymer (adhesive copolymer). This molded part has substantially the outer shape of the insert 6 and the insert 6.
In the range of the case 1. Subsequently, the ring-shaped insert 6
Is injection molded on or in the molded part produced in the preceding method step. Thereby, when the sticky copolymer is used to form a molded part, the sticky copolymer is partially melted, and the molded part is formed in an injection molding process for forming the ring-shaped insert 6. And the material of the ring-shaped insert 6 are welded and connected.

Subsequently, the bearing bush 8 is fixed to the insert 6 manufactured as described above. Subsequently, a bearing ring 4 having a seal ring 5 is mounted on the valve ball 3,
They are connected to each other by a ring-shaped insert 6. In this pre-assembled state, the components forming the inner part of the shut-off valve, namely the valve ball 3, the bearing ring 4, the seal ring 5, the bearing bush 8 and the ring-shaped insert 6, act as an adhesive (adhesive). Along with a molded part made of a synthetic resin, which is not shown in the figure, it is placed in an injection mold, not shown, which produces the external shape of the case 1, and coated with a synthetic resin, especially polyethylene, by injection molding. At the time of this new injection molding process, the material of the molded part serving as the internal shape for the case is newly melted, so that a welded connection portion is also formed between the synthetic resin of the case 1 and the synthetic resin of the molded part. You. A number of notches 6a are provided in the insert 6 so that the synthetic resin of the case 1 can reach the valve ball 3 in the radial direction.

An insert 6 that connects the bearing rings 4 to each other and supports a bearing bush 8 for the switching shaft 7 is disposed in the case 1 formed by an injection mold, thereby forming the integral short pipe 2. Despite the fact that the case occurs in the injection mold,
The valve is divided into an outer part forming case 1 and an inner part surrounded by case 1.

In order to form the outer contour of the ring-shaped insert 6 and the inner contour of the case 1 within the range of the ring-shaped insert 6, a molded part made of synthetic resin is used to form the inner part, the outer part and the outer part. A material-integrated sealing connection is created between the inner part of the case 1 forming the part. Therefore, the passage of the medium to be blocked between the inner part and the inner surface of the outer part is prevented.

After the synthetic resin case 1 integrally formed with the connecting short pipe 2 is manufactured as described above, the ring seal 11 of the switching shaft 7 is inserted into the bearing bush 8, thereby connecting the switching shaft 7 a. Engages with the concave portion of the valve ball 3. Subsequently, the bearing bush 8
The bearing ring 12 is screwed onto the outer end face of the bearing. This bearing ring has a square section 7
Due to the shoulder formed between b and the central part of the switching shaft 7, the switching shaft 7 is prevented from falling out of the bearing bush 8. Finally, in the case of the present embodiment, the switching dome 9 is mounted on the square portion 7b of the switching shaft 7 and fixed by the screw 9b. The ball valve is ready for use, and the end faces of its two connecting short tubes 2 can be inserted into the respective plastic conduits, in particular the gas supply conduits.

As is apparent from the drawing, in the case of the illustrated embodiment, a ball having an integral synthetic resin case 1 and a flow hole 3 a of the valve ball 3 corresponding to the flow hole 2 a of the connecting short pipe 2. Since the valve is formed, no leakage losses occur in the open ball valve. The material-integral connection between the parts 3, 4, 5, 8 forming the inner part and the synthetic resin of the case 1 and the passage of the medium to be sealed between the inner part and the outer part, Danger is gone. Thus, even when the pressure of the medium to be shut off is high, the shut-off valve produced in this way ensures a leak-free inner seal.

[Brief description of the drawings]

FIG. 1 is a view exemplarily showing a vertical section of a ball valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Connection short pipe 2a Communication hole 3 Valve ball, shut-off element 3a Communication hole 4 Bearing ring 5 Seal ring 6 Insert 6a Notch 7 Switching shaft 7a Connecting portion 7b Square portion 8 Bearing bush 9 Switching dome 9a Wrench surface 9b Screw DESCRIPTION OF SYMBOLS 10 Seal 11 Ring seal 12 Bearing ring

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] September 22, 2000 (2000.9.22)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001] The present invention is characterized in that the case is made of synthetic resin and has two connecting short pipes, and a shut-off element adjustable between a flow position and a shut-off position via an operation unit is provided in the case at least with the bearing ring. The inner part, which is supported by the sealing ring and has the blocking element and the bearing and the sealing ring, the bearing bush and the insert, is pre-assembled and injection molded with synthetic resin using glue to form the case And a method for fabricating a shut-off valve for a conduit, the method comprising: The invention further relates to a shut-off valve made by this method.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002] Such a method for producing a shut-off valve is known, for example, from DE-A 44 42 797. In the case of this known method,
In the first method step, first the ball, a part of the switching shaft and the lower part of the bearing pin are covered by injection molding with a plastic covering. In a subsequent working step, an elastic insert is arranged between the flange areas on the outer surface of the synthetic resin cover produced in the first step, and in a subsequent working step on the cover with the elastic insert. The case is formed by injection molding a synthetic resin. This method for making a plastic case for a shut-off valve is very cumbersome. This is because the two-part valve case must be made of synthetic resin. The resilient insert used serves to separate the inner cover from the outer valve case. On the other hand, outside the area of the elastic insert, the two plastics of the inner cover and the outer valve case are integrally connected to each other. In particular, due to the formation of a two-part valve case, an inner cover and an outer valve case, this known method cannot be used economically.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

Another method for manufacturing a ball valve with a synthetic resin case is disclosed in EP 0
This is known from U.S. Pat. In the case of this known method, in order to form a synthetic resin case, the pre-assembled inner part is inserted into an injection mold which, in the pre-assembled state, produces the outer shape of the case and the flow hole of the connecting short pipe. And
Subsequently, the periphery is covered with a synthetic resin by injection molding. Such fabrication of a synthetic resin case, in which the entire valve is divided into an outer part and an inner part, has proved effective in practice. By dividing the pre-assembled inner part and the injection-molded outer part, when the case formed in the injection mold is cooled, relative shrinkage of the two case parts occurs, and the case is formed radially inward. Shrinkage is prevented. Thereby,
The valve ball gets stuck in the case and does not move.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

The shut-off valves produced in this way are closed, especially when used in conduits with large-diameter connecting stubs and in conduits with high conveying pressures, in particular when used as gas shut-off valves. Despite the shutoff valve, the medium to be shut off is forced between the inner part and the outer part, that is, between the outer surface of the shutoff element and the bearing ring and the seal ring and the inner surface of the synthetic resin case, Leakage of the shut-off valve can actually occur. Such leaks should always be avoided, especially when using valves to shut off gas lines.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005] Starting from now, the problem underlying the present invention is that the medium to be shut off does not pass between the inner and outer parts of the valve, so that it can be manufactured more simply and at lower cost. The object of the present invention is to improve a method for manufacturing a shut-off valve for a conduit having a synthetic resin case. It is a further object of the present invention to provide a shut-off valve made according to this method.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006] A methodical solution to this problem consists of: a) forming by injection molding a molded part made of synthetic resin, which in the area of the insert substantially matches the outer shape of the insert and the inner shape of the case, b) method step a) C) welding and joining the synthetic resin of the molded part formed in the above step and the material of the insert, and simultaneously injection molding the synthetic resin forming the insert on or in the molded part; c) blocking element, bearing ring, seal ring , Bearing bush and insert (
Assembling the inner part of the shut-off valve consisting of the molded part) and inserting the inner part into the injection mold, d) welding the synthetic resin of the molded part forming at least a part of the internal shape of the case and the material of the case At the same time, the inner part pre-assembled in method step c) is coated by injection molding synthetic resin.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

In the method according to the invention, the adhesive used to connect the inner and outer parts of the shut-off valve is at the same time, in the area of the insert, as a molded part for the outer shape of the insert and the inner shape of the case. Work. The molded plastic part produced in the first method step is melted by the injection-molded synthetic resin during the subsequent injection molding coating to form the insert and the valve case, respectively. A material-integral welding connection occurs between the insert and between the molded part and the valve case.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), CA, JP, NZ, US F term (reference) 3H017 AA00 3H051 AA07 CC06 CC14 CC16 DD07 EE04 3H054 AA03 BB18 CC05 EE04 4F213 AD05 AD21 AH05 WA05 WA15 WA53 WA60 WB01 Assembling, d) welding and connecting the synthetic resin of the molded part which forms at least a part of the internal shape of the case (1) and the material of the case (1), and at the same time the inner part pre-assembled in method step c) Is coated by injection molding a synthetic resin.

Claims (5)

[Claims] The case (1) is made of synthetic resin and has two connecting short tubes (2).
), The shut-off element (3) being adjustable between a flow position and a shut-off position via an operating unit is supported in the case by at least a bearing ring (4) and a seal ring (5), and the shut-off element (3) And the inner part with bearings and seal rings (3, 4), in the pre-assembled state, is coated by injection molding synthetic resin using an adhesive to form the case (1). A method for manufacturing a shut-off valve for a conduit, comprising: a) the outer shape of the insert (6) and the case (1) in the area of the insert (6);
A molded part made of synthetic resin that almost matches the internal shape of) is formed by injection molding.
b) The synthetic resin of the molded part formed in method step a) and the material of the insert (6) are welded and connected, and at the same time, the synthetic resin forming the insert (6) is injection molded on or in the molded part. C) valve ball (3), bearing ring (4), seal ring (5), bearing bush (
8) and assembling the inner part of the shut-off valve consisting of the insert (6) and the molded part;
d) welding the synthetic resin of the molded part, which forms at least part of the internal shape of the case (1), to the material of the case (1) and, at the same time, connecting the inner part pre-assembled in method step c) with the synthetic resin Coating by injection molding. 2. The method according to claim 1, wherein the synthetic resin for the molded part is a thermoplastic synthetic resin. 3. The method according to claim 1, wherein an adhesive copolymer is used as the synthetic resin for the molded part. 4. A conduit shut-off valve manufactured by the method according to claim 1, wherein the inner part and at least a part of the case (1) (outer part) are injection-molded with synthetic resin. A shut-off valve characterized in that the shut-off valve is integrally connected to each other via a molded part. 5. The shut-off valve according to claim 4, further comprising an insert (6) connecting the bearing rings (4) to one another. Insert (6) to form additional anchoring points for
) And a plurality of cutouts (6a) formed in the injection-molded part.