WO2000004312A1

WO2000004312A1 - Method for constructing a valve

Info

Publication number: WO2000004312A1
Application number: PCT/US1999/011129
Authority: WO
Inventors: Kam Molavi
Original assignee: Nordstrom Valves, Inc.
Priority date: 1998-07-16
Filing date: 1999-05-20
Publication date: 2000-01-27
Also published as: AU4006299A

Abstract

A method of constructing a valve comprises the steps of: providing an inlet pipe (32) and an outlet pipe (40), each of which includes a first end (34, 42) and a second end (36, 44); providing a hollow body (12) having a side wall (14) of substantially constant cross section and defining a cavity, wherein the body has an open top end and further has first and second apertures (20, 22) positioned in opposing locations in the side wall (14); attaching the inlet (32) and outlet (40) pipes to the hollow body (12) such that the first ends (34, 42) of the inlet (32) and outlet (40) pipes are positioned within the hollow body cavity, and the second ends (36, 44) of the inlet (32) and outlet (40) pipes are positioned outside of the hollow body cavity; and inserting a flow regulating unit (48) within the hollow body cavity. The flow regulating unit (48) includes a valve member (50) with a flow passage (52) therein, and the flow regulating unit (48) is positioned within the body cavity such that the flow passage is at a height so as to be aligned with the inlet (32) and outlet (40) pipes. With this construction method, which can employ readily available materials for the body and inlet and outlet pipes, the cost of the valve can be reduced significantly, and valves of different sizes and configurations can be formed without the need for multiple casting molds of different sizes.

Description

METHOD FOR CONSTRUCTING A VALVE

Field of the Invention

The present invention relates generally to valves, and relates more particularly to the construction of valves.

Background of the Invention

Valves are common components of almost any piping system. Although they can be constructed in many different configurations and sizes, a typical valve will include a few basic elements. These include: a valve body that houses internal components within an internal cavity; inlet and outlet pipes leading to and from the valve body; a valve member that is positioned within the cavity of the valve body and that includes a passageway for fluid flow; inlet and outlet seats that seal the contact points between the inlet and outlet pipes and the valve member; and a valve stem or other structure or mechanism that extends outside the cavity for turning the valve member within the valve body cavity. These components are attached such that fluid entering the valve through the inlet pipe is either allowed to flow through the valve member to the outlet pipe or prevented from such flow based on the orientation of the valve member passageway relative to the valve body.

Valves are typically constructed such that the valve body and inlet and outlet ports are integrally formed. The valve body and inlet and outlet ports are commonly formed by casting, machining, or a combination of these processes (for cost reasons, casting is typically preferred). In a casting process, the valve body may either be formed as two "clamshell" halves that are welded or otherwise attached together or as a single hollow piece; in either instance, typically the inlet and outlet ports are integrally formed with the valve body piece(s) at the same time. In the clamshell process, when the valve body is cast, two molds (a core mold to form the inside surface of the valve body, and a cavity mold to form the outer surface) are used to form the body into the desired shape. When the valve body is formed as a single piece, a permanent mold is used to form the outer surface and a temporary mold formed of an erodable or dissolvable material such as sand, is used to form the inner surface of the valve body.

One significant shortcoming of casting a valve body is the inability to modify the size or configuration of the valve to an appreciable degree. Each valve size is typically formed with a different mold as is each type of valve (e.g., plug or ball). Thus, producing an entire product line of valves of different sizes and configurations requires a similar number of different molds. The costs of the molds can be quite high, particularly for large valves, which are often produced only in relatively small quantities.

Also, for the single piece casting process, each valve produced requires its own temporary mold. Although the erodable or dissolvable materials used as the temporary internal molds are often not particularly expensive, the production of the temporary molds can be quite time-consuming.

In view of the foregoing, a valve construction technique that provides valves in multiple sizes and configurations without great material and/or labor cost is desirable.

Summary of the Invention

In view of the foregoing, it is an object of the present invention to provide a method of constructing a valve that addresses the high cost of casting valve bodies. It is also an object of the present invention to provide such a method that provides a valve that meets the performance and reliability parameters of currently available valves.

It is another object of the present invention to produce such a method that can be used to construct valves of different sizes and configurations. These and other objects are satisfied by the present invention, which is directed to a method of constructing a typical valve with readily available materials.

The method comprises the steps of: providing an inlet pipe and an outlet pipe, each of which includes a first end and a second end; providing a hollow body having a side wall of substantially constant cross section and defining a cavity, wherein the body has an open top end and further has first and second apertures positioned in opposing locations in the side wall; attaching the inlet and outlet pipes to the hollow body such that the first ends of the inlet and outlet pipes are positioned within the hollow body cavity, and the second ends of the inlet and outlet pipes are positioned outside of the hollow body cavity; and inserting a flow regulating unit within the hollow body cavity. The flow regulating unit includes a valve member with a flow passage therein, and the flow regulating unit is positioned within the body cavity such that the flow passage is at a height so as to be aligned with the inlet and outlet pipes. ith this construction method, which can employ readily available materials for the body and inlet and outlet pipes, the cost of the valve can be reduced significantly, and valves of different sizes and configurations can be formed without the need for multiple casting molds of different sizes.

Brief Description of the Drawings Figure 1 is a cutaway perspective view of a valve of the present invention .

Figure 2 is a schematic diagram illustrating the steps employed in constructing the valve of Figure 1.

Figure 3 is a top section view of the valve of Figure 1 with the plug rotated to its open position.

Detailed Description of the Invention

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Referring now to the drawings, a plug valve of the present invention, designated broadly at 10, it is shown in Figure 1. Generally, the plug valve 10 includes a body 12, an inlet pipe 32, an outlet pipe 40, and a plug assembly 48. These structures are discussed in more detail hereinbelow.

Still referring to Figure 1, the body 12 includes a cylindrical wall 14, which has a cylindrical inner surface 16 that defines a cavity 17 therein. The wall 14 also includes a cylindrical outer surface 18. An inlet aperture 20 sized to receive the inlet pipe 32 is included in a central portion of the wall 14; a corresponding outlet aperture

22 sized to receive the outlet pipe 40 is included in the wall 14 at a location that is diametrically opposed across the cavity 17 from mat of the inlet aperture 20. The body 12 also includes a bottom plate 24 that is fixed to the lower end of the wall 14. The bottom plate 24 includes a centrally located circular recess 25. A top cover 26 that rests on the upper ends of the sidewalls 14 is fixed to the sidewalls 14 with bolts

30. A collar 2.8 is fixed to the upper surface of the top cover 26 via bolts 31.

The inlet pipe 32 comprises a length of pipe having an internal end 34 and an external end 36. The inlet pipe 32 extends through the inlet aperture 20 of the wall 14 such that the internal end 34 is positioned within the cavity 17, and the external end

36 of the inlet pipe 32 is positioned outside the outer surface 18 of the wall 14. The internal end 34 is arcuate and configured so that, as it contacts the plug assembly 48, it forms a sealing "seat" with the plug assembly 48 (see Figure 3). A flange 38 is illustratively and preferably fixed to the external end 36 to facilitate attachment of the valve 10 between two external pipes through which fluid flows.

The outlet pipe 40 also comprises a length of pipe having an internal end 42 and an external end 44. Similar to the inlet pipe 32, the outlet pipe 40 extends through the outlet aperture 22 of the wall 14 so that the internal end 42 is positioned within the cavity 17 and the external end 44 is positioned outside of the outer surface 18. The internal end 42 is arcuate and fashioned to contact and form a sealing seat with the plug assembly 48. The external end 44 also includes a flange 46 to facilitate attachment to an external piping system.

The plug assembly 48 includes a plug 50, a stem 54 and a spring 56. The plug

50 resides within the cavity 17 and is a tapered cylinder, with its larger end resting beneath the lower surface of the top cover 26 and its lower end positioned just above the upper surface of the bottom plate 24. A flow passage 52 passes through the plug

50 at the general height of the inlet pipe 32 and outlet pipe 40. The spring 56 fits within the recess 25 of the bottom plate 24 and against the lower end of the plug 50; the spring 56 is in compression and biases the plug 50 upwardly to maintain it in position within the cavity 17. The stem 54 is fixed to the upper surface of the plug 50 and extends upwardly therefrom through the top cover aperture 27 and collar 28. The stem 54 includes a square projection 55 that is sized and configured to receive a wrench or other torque-inducing device to enable the plug 50 to be rotated between closed and open positions, (i.e., from a position in which the flow passage 52 is parallel with and connects the inlet and outlet pipes 32, 40 to a position in which the flow passage 52 is perpendicular to the inlet and outlet pipes 32, 40).

The operation of the valve 10 can best be understood by referenced to Figure 3, wherein the plug 50 is shown in its open position. In the open position, the flow passage 52 is aligned with the inlet and outlet pipes 32, 40, thereby enabling fluid to flow from the outlet pipe 32 through the plug 50 and into the outlet pipe 40. Ninety degree rotation of the projection 55 of the valve stem 54 (typically with a wrench) rotates the flow passage 52 to the closed position, in which fluid is prevented from flowing from the inlet pipe 32 to the outlet pipe 40. The construction of the valve 10 is schematically illustrated in Figure 2. As examination of Figure 2 demonstrates, the major components of the valve (i.e., the body 12, the inlet pipe 32, the outlet pipe 40, and the plug assembly 48) are manufactured as separate subassemblies and are combined to complete construction of the valve 10. The body 12 is formed by first forming the wall 14, which, being annular in shape, can be formed from a short length of pipe or tubing of a desired size. Those skilled in this art will recognize that, although an annular length of tubing is illustrated herein, tubing of other cross-sections may also be suitable for use with the present invention. For example, square, rectangular, pentagonal, hexagonal, octagonal, or parallellogrammatic tubing may be selected. It is preferred that the cross-section of the tubing be substantially constant, as such tubing is typically more readily available than tubing of non-constant cross-section.

Once the tubing is cut to a desired length for the wall 14, the bottom plate 24, which can be formed from sheet material of a desired thickness, is fixed to the lower edge of the wall 14. This attachment can be carried out by welding the parts together, or they can be bolted or attached via some other attachment technique known by those skilled in this art to be suitable for attachment of such components. If the bottom plate 24 is to include a recess (as is illustrated in Figures 1 and 3) or other changes in contour to its upper surfaces, preferably these are added prior to the attachment of the bottom plate to the wall 14.

Illustratively, next the inlet and outlet apertures 20, 22 are formed in the wall 14. These should be formed in a size and configuration suitable for receiving the inlet and outlet pipes 32, 40; the size and configuration may vary depending upon the manner used to attach the inlet and outlet pipes 32, 40.

Those skilled in this art will recognize that the sequence of steps in forming the body 12 can vary. For example, it may be advantageous to form the inlet and outlet apertures 20, 22 prior to cutting the tubing to length and/or attaching bottom plate 24 to the tubing.

In a separate, and potentially simultaneous, operation, the inlet and outlet pipes 32, 40 can be formed from existing pieces of pipe. The diameter pipe should be sized so that the inlet and outlet pipes 32, 40 can be inserted into and through the inlet and outlet apertures 20, 22 and attached to the wall 14. Once the inlet and outlet pipes 32, 40 are cut to a desired length, the internal ends 34, 42 are arcuately shaped as desired to form a seat with the plug 50. It may be desirable to attach a seating material, such as an elastomerics polymeric (e.g., PTFE), or alloy (e.g. nickel or zinc) coating, on the internal ends 34, 42 to improve the seating and sealing of the plug 48 with the inlet and outlet pipes 32, 40. Also, the flanges 38, 46 are attached to the external ends 36, 44 of the inlet and outlet pipes 32, 40, although in some embodiments (particularly those in which the valve can be welded directly to an external pipe is employed), one or both of the flanges 38, 46 may be omitted entirely.

Illustratively (Figure 2), the inlet and outlet pipes 32, 40 are then positioned within the inlet and outlet apertures 20, 22 of the body 12 and fixed into place. The internal ends 34, 42 should be positioned such that they extend inside the inner surface 16 of the wall 14 and so that they will contact the plug 50 once it is positioned within the cavity 17. The external ends 36, 44 should be positioned outside the outer surface 18. The inlet and outlet pipes can be welded to the wall 14 or attached via some other technique known to those skilled in this art to provide an airtight or watertight seal as needed.

Referring still to Figure 2, the plug assembly 48 is then lowered into the cavity 17 of the body 12. The plug 50 should contact the internal ends 34, 42 of the inlet and outlet pipes 32, 40 to form seals therewith. The plug 50 may be coated with seating material such as those described above. If the spring 56 or any other additional structure or component is to be positioned below the plug 50, it should be added prior to the insertion of the plug assembly 48.

In some instances, it will be necessary or desirable to adjust the length or shape of the internal ends 34, 42 of the inlet and outlet pipes 32, 40 or to modify the diameter of the plug 50 in order to optimize the seating and sealing between the plug

50 and the inlet and outlet pipes 32, 40. Typically, these types of modifications would be part of an iterative process, in which the plug assembly 48 is lowered into the cavity 17 and its interaction with the inlet and outlet pipes 32, 40 assessed. It may be preferred in some instances to perform such adjustment prior to fixing the inlet and outlet pipes 32, 40 to the wall 14.

After the plug assembly 48 is lowered into place, the top cover 26 and collar

28 are positioned over the upper edge of the wall, with the stem 54 extending upwardly through the aperture 27 and collar 28. The top cover 26 and collar 28 are then bolted into place with, respectively, bolts 30, 31. This process retains the plug assembly 48 in place within the cavity 17.

The materials for the valve 10 can be any known to those skilled in this art to be suitable for valve construction. For example, the wall 14, bottom plate 24, top plate 26, and inlet and outlet pipes 32, 40 can be formed of metals such as stainless steel, carbon steel, alloy steel, aluminum, brass, bronze, titanium and the like, or even combinations thereof. These components can also be formed of polymeric materials, such as polyethylene, polypropylene and the like. The materials of construction should be selected based on the operating conditions the valve is expected to experience. Similarly, the plug assembly 48 should be formed of materials known by those skilled in this art to be suitable for this purpose. It should also be understood that the present invention is not limited to the illustrated plug valve. Other types of top entry valves, including ball valves and check valves, that include a flow regulating unit configured such that a valve member

(such as a plug or ball) can be lowered into place within a valve body cavity after the valve body is formed, are also candidates for construction by the method of the present invention. In addition, the present invention can be used with valves having multiple inlet and outlet lines.

The foregoing discussion demonstrates how valves of the present invention reduce the cost of raw materials and labor during production. Employing readily available materials, such as the tubing of substantially constant cross-section used for the body wall, the pipes used for the inlet and outlet pipes, and the sheet used for the bottom plate, then assembling them, can be considerably less expensive than casting these components, even as a single piece. In addition, the construction method of the present invention enables valves of virtually any size or configuration to be constructed without the need for separate casting molds for each. Moreover, finishing of the parts may be facilitated because the parts can be worked on separately before being assembled. For these reasons, the present method can reduce costs significantly.

The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures.

Claims

THAT WHICH IS CLAIMED IS;

1. A method of constructing a valve, comprising the steps of: providing an inlet pipe and an outlet pipe, each of which includes a first end and a second end; providing a hollow body having a side wall of substantially constant cross section defining a cavity, said body having an open top end and further having first and second apertures positioned in opposing locations in said side wall; attaching said inlet and outlet pipes to said hollow body such that said first ends of said inlet and outlet pipes are positioned within said hollow body cavity, and said second ends of said inlet and outlet pipes are positioned outside of said hollow body cavity; inserting a flow regulating unit within said hollow body cavity, said flow regulating unit including a valve member with a flow passage therein, said flow regulating unit being positioned within said body cavity such that said flow passage is at a height so as to be aligned with said inlet and outlet pipes.

2. The method defined in Claim 1, wherein said valve member comprises a plug.

3. The method defined in Claim 1, wherein said attaching step comprises welding said inlet and outlet pipes to said hollow body.

4. The method defined in Claim 1, wherein said inlet and outlet pipes are formed of steel.

5. The method defined in Claim 1, wherein said hollow body is substantially annular in cross-section.

6. The method defined in Claim 1, wherein said first ends of said inlet and outlet pipes and said flow regulating unit are configured and positioned such that said first ends of said inlet and outlet pipes form seats with said flow regulating unit.

7. The method defined in Claim 6, wherein said first ends of said inlet and outlet pipes are arcuately shaped to contact and mate with said valve member.

8. A method of constructing a valve, comprising the steps of: providing an inlet pipe and an outlet pipe, each of which includes a first end and a second end; providing an annular hollow body having a substantially cylindrical wall of substantially constant cross section and defining a cavity, said body having a closed bottom end, an open top end and first and second apertures positioned in opposing locations in said wall; attaching said inlet and outlet pipes to said hollow body such that said first ends of said inlet and outlet pipes are positioned within said hollow body cavity, and said second ends of said inlet and outlet pipes are positioned outside of said hollow body cavity; inserting a flow regulating unit within said hollow body cavity, said flow regulating unit including a valve member with a flow passage therein, said flow regulating unit being positioned within said body cavity such that said flow passage is at a height so as to be aligned with said inlet and outlet pipes.

9. The method defined in Claim 8, wherein said valve member comprises a plug.

10. The method defined in Claim 8, wherein said attaching step comprises welding said inlet and outlet pipes to said hollow body.

11. The method defined in Claim 8, wherein said inlet and outlet pipes are formed of steel.

12. The method defined in Claim 8, wherein said first ends of said inlet and outlet pipes and said flow regulating unit are configured and positioned such that said first ends of said inlet and outlet pipes form seats with said flow regulating unit.

13. The method defined in Claim 12, wherein said first ends of said inlet and outlet pipes are arcuately shaped to contact and mate with said valve member.

14. A top-entry valve, comprising: a hollow body having a side wall of substantially constant cross section and defining a cavity, said body having a closed bottom end, an open top end and first and second apertures positioned in opposing locations in said wall; an inlet pipe and an outlet pipe, each of which includes a first end and a second end, said inlet and outlet pipes being attached to said hollow body such that said first ends of said inlet and outlet pipes are positioned within said hollow body cavity, and said second ends of said inlet and outlet pipes are positioned outside of said hollow body cavity; a flow regulating unit positioned within said hollow body cavity, said flow regulating unit including a valve member with a flow passage therein, said flow regulating unit being positioned within said body cavity such that said flow passage is at a height so as to be aligned with said inlet and outlet pipes; wherein said first ends of said inlet and outlet pipes are arcuately shaped to contact and mate with said valve member and form seats therewith.

15. The valve defined in Claim 14, wherein said valve member comprises a plug.

16. The valve defined in Claim 14, wherein said inlet and outlet pipes are welded to said hollow body.

17. The valve defined in Claim 14, wherein said inlet and outlet pipes are formed of steel.

18. The valve defined in Claim 14, wherein said hollow body is substantially annular in cross-section.

19. The valve defined in Claim 14, wherein said first ends of said inlet and outlet pipes and said flow regulating unit are configured and positioned such that said first ends of said inlet and outlet pipes form seats with said flow regulating unit.

20. The valve defined in Claim 19, wherein said first ends of said inlet and outlet pipes are arcuately shaped to contact and mate with said valve member.