GB2024053A - Valve gate for a gate valve - Google Patents

Abstract

A valve gate for a gate valve is constructed from sheet metal parts including two laterally spaced coplaner flat plates 1 together forming a carrying frame, and two dished members 2 spot welded (at 4) to the plates 1. Before welding, the members 2 are formed, in flat areas 3 which in the finished valve lie close to and oppose respective faces of the plates 2, with circular bulges or pimples which, prior to welding contact the opposing faces of the plates 1 to space the flat portions of areas 3 from plates 1. The members 2 are welded to plates 1 by spot welds each formed at the location of a respective said bulge. After welding, the valve gate is brought to the desired dimensions and angle between the rims 5 of members 2 by sizing in a sizing press, during which deformation occurs in the region of the bulges. <IMAGE>

Description

(12)UK Patent Application,,,,GB (,,) 2 024 053 A (21) Application No

7905041 (54) Valve gate for a gate valve press, during which deformation oc (22) Date of filing curs in the region of the bulges.

13 Feb 1979 (57) A valve gate for a gate valve is (23) Claims filed constructed from sheet metal parts

13 Feb 1979 including two laterally spaced co (30) Priority data planar flat plates 1 together forming (31) 2927778 a carrying frame, and two dished 2831019 (32) 24 Jun 1978 members 2 spot welded (at 4) to 14 Jul 1978 the plates 1. Before welding, the (33) Fed Rep of Germany members 2 are formed, in flat areas (DE) 3 which in the finished valve lie (43) Application published close to and oppose respective 9 Jan 1980 faces of the plates 2, with circular (51) INT CL3B23K 11/10 bulges or pimples which, prior to F1 6K 3/314 welding contact the opposing faces (52) Domestic classification of the plates 1 to space the flat 83A 169 portions of areas 3 from plates 1.

133R 2G 6 F2V E1J The members 2 are welded to (56) Documents cited plates 1 by spot welds each formed GB 1353775 at the location of a respective said GB 1291481 bulge. After welding, the valve gate GB 1267943 is brought to the desired dimen GB 1202882 sions and angle between the rims 5 GB 1156215 of members 2 by sizing in a sizing GB 614262 GB 429459 GB 245340 GB 231060 Welding Process Fig. 1 Technology pp 164-169 01 10 published by Cambridge 0 0 by P T Houldcroft i 1 0 University Press 1977 FOO Welding Processes and Technology pp 37-39, I by D Romans and Eric N Simons published by Sir Isaac Pitman and Sons Ltd 1968 1-1 1:_1A _1C ZI-N I r1%.1 - __- 2 1 ERRATUM SPECIFICATION NO 2024053

Front page, Heading (3 1) for 2927778 read 2827778 THE PATENT OFFICE 8 August 1980 Bas 7785719 (14) Agents Forrester Ketley Et Co 1 5.551 ERRATA SLIP ATTACHED c c h c h 4 c c 1 1 55 GB2024053A 1 SPECIFICATION

Valve gate for a gate valve THIS INVENTION relates to a valve gate for a gate valve, i.e. for a valve of the kind cornprising a valve body in which an inlet and an outlet passage open into a gate chamber on opposite sides of the chamber, in respective opposing ports, and a valve gate, accommodated within the chamber is movable linearly in a direction generally perpendicular to the line of centres of said opposing ports between an open position in which said ports are substantially unobstructed, and a closed position in which sealing surfaces on opposite sides of the valve gate engage respective sealing surfaces provided around said ports. In gate valves, the sealing surfaces around the opposing ports, and consequently the sealing surfaces on the gate may lie in planes which are parallel, or may be relatively inclined to some extent so that there is a wedging action as the gate is moved into its closed position, the valve gate in this case being referred to herein as a wedge gate.

Valve gates for gate valves are subject to various stresses in use and must be constructed to withstand such stresses whilst meeting various other requirements as to effectiveness of the seal formed in use between inlet and outlet passages of the gate valve when the valve is closed, resistance to corrosion, etc.

Valve gates for gate valves are generally castings and their heavily stressed sealing surfaces are made of rustless material. Gates for relatively small diameters are often made of non-rusting materials as forgings or cast- ings. Gates for relatively large diameters can be welded together from non-rusting plates. Most of the difficulties in gate production arise from the machining of the fitting surfaces and, in the case of small cast or forged gates, the considerable expenditure on expen110 sive corrosion resistant metals due to the thick walls of the casting. On the other hand, constructions in which only the sealing surfaces are made of corrosion resistant metal are unsuitable for mass production because considerable labour time is required to contrive the sealing surfaces.

It is an object of the invention to develop a gate which is suitable for mass production at very reduced cost and which can be made making maximum use of commercially available corrosion resistant sheet materials.

According to the invention there is provided a component comprising a plurality of sheet metal members, including two such sheet metal members disposed face to face in contact with one another, said two members comprising a first and a second member of which the first member is welded to the opposing surfaces of said two members, and at which point of contact a bulge on one of said opposing surfaces engages the other of said opposing surfaces to provide the point of contact, and wherein, in the region of each said point, at least one of the contacting members is deformable, said first member being welded to said second member at said point of contact by a spot weld formed at said point of contact.

It is possible to manufacture a valve gate embodying the invention which requires the very minimum of finishing treatment. The gate, after welding of the members thereof together, can be given subsequent pressing treatment e.g. in a jig press, so that by deformation of the respective members in the regions of said bulges the required accuracy of wedge angle or seat dimensions can be achieved, e.g. to tolerances of 0.05 mm. By the nature of its construction the gate is so designed that the deformable regions in the zones of the weld spots deform only when the gate is strongly stressed, as it is, for example, when pressed in a press to bring it to the fitting size. The said bulges may be so devised that e.g. five times the rated working pressure cannot cause any changes in'their dimensions. Also, the desired form of the bulges can be calculated accurately and they can be designed to suit the pressure in the fitting in which they are used.

Preferably, a weld protuberance is formed in the highest zone of each said bulge. This feature assists rational production.

Preferably said carrying frame comprises one or more sheet metal parts affording edges extending in the direction in which, in use, the valve gate is moved to open or close the valve in which the gate is fitted, said edges being formed as guide formations for cooperation with complementary formations on a gate valve body. This feature enables the gate to be used in fittings using known constructions.

If the gate components are sheet metal parts formed by chipless machining, a gate can be produced requiring virtually no aftertreatment or at most merely deburring. The use of smooth plates makes it unnecessary to machine the sealing surfaces of the gate.

An embodiment of the invention is described below with reference to the drawings wherein:

Figure 1 is a front view of a wedge gate embodying the invention, Figure 2 is a plan view showing fragmentary views in horizontal section of the gate of Fig. 1 and of a variant thereof.

Figure 3 is a corresponding view in vertical section, and Figure 4 is a fragmentary sectional view to an enlarged scale of a part of the gate.

The wedge gate shown in Fig. 1 comprises two metal members 2 spot-welded to opposite 65 second member at a point of contact between 130 sides of a further member, also of sheet 2 GB2024053A 2 metal, forming a carrying frame 1. The members 2 are dished and each is joined by spotwelds 4 in zones 3 to the frame 1. The members 2 are arranged with their hollowed or concave sides facing outwardly, away from the frame 1, in generally opposite directions. The rim 5 of each dished member 2 forms a respective one of the two sealing surfaces of the gate.

As will be apparent from Figs. 1 and 3 the carrying frame comprises two metal plates which, as viewed in Fig. 1, are spaced apart on opposite sides of a vertical axis of symmetry (not shown) of the gate, to define there- between a vertically extending passage for a gate operating spindle (not shown) the two plates being held in position relative to one another, both by the dished members 2, which are welded to these plates, and by bent sheet metal connecting members welded on opposite sides of both plates at the upper ends of the plates as viewed in Figs. 1 and 3.

Said bent sheet metal connecting members together define a collar, aligned with the passage for the gate operating spindle through which the spindle passes in use, the collar together with locating shoulders formed in opposing edges of said two plates, defining a locating formation for a retaining element, such as a nut, (not shown) which in use cooperates with the operating spindle.

Referring to Fig. 2, the right hand side thereof shows the embodiment already discussed in which each of said two metal plates to which the dished members 2 referred to are welded is formed as a respective integer, whereas the left hand side thereof shows a variant in which each said plate is formed of two superimposed metal sheets 6, 7 each of which is flat over its major portion, which lies flat against and is welded to the corresponding major portion of the superimposed sheet, - each said sheet having, adjacent its edge which is furthermost from the vertical axis of the gate, as viewed in Fig. 1 and which extends parallel with said axis, a minor portion, providing said edge, which is bent away from the plane of the respective major portion to lie in a parallel plane spaced from the corresponding plane of the minor portion of the superimposed sheet, to define with said other minor portion a channel 8 provided by the respective said plate, to receive a respective guide rib 9, of the form indicated in broken lines, in a gate valve housing provided with such a guide rib, the channel and guide rib cooperating in use to guide the valve gate during its movement parallel with said axis, between its opened and closed positions.

Where, as indicated to the right in Figure 2, each plate is a unitary member, the edge thereof furthest from the vertical axis of the gate, as viewed in Figure 1, extends parallel with this axis and the porton of the plate providing this edge, locates, in use, in a guide 130 groove, provided in another form of gate housing, the guide grooves and plate edge portions again cooperating to guide the gate in its linear opening and closing movements.

As shown in Fig. 2 and also in Fig. 3, each dished member 2 is so formed as to provide, on its side facing the other member a vertically extending channel 10 of substantially semi-circular cross-section, and, on its opposite side a corresponding rib, the channels being provided in the region between the two spaced apart plates forming the carrying frame and defining, with the adjacent edges of said plates, a generally cylindrical passage, to receive the operating spindle, extending vertically and having, as its axis the vertical axis of the valve gate.

As indicated above, the members 2 are secured to the carrying frame by spot welds 4. In manufacture of the valve gate, the members 2 or the metal sheet or sheets forming each plate of the carrying frame, or both the members 2 and the carrying frame, are formed with localised formations each providing a respective bulge on one side of the sheet material in question and a corresponding depression on the other side of the sheet material. One such formation is indicated at 11 in the fragmentary sectional view of Fig. 4. The bulges and depressions may be generally circular as viewed perpendicular to the respective area of the sheet material in question, or may be in the form of corrugations. At the highest point of each said bulge, i.e. the point furthest from the plate of the respective member of sheet material in the area around the bulge, is further formed a weld protuberance or pimple, i.e. an area small in relation to the bulge but of substan- tially greater curvature than the bulge, said protuberance, like the bulge itself, being formed by pressing the sheet material in question so that a corresponding more pronounced recess is formed, on the other side of the sheet material at the bottom of the depression corresponding to the bulge. Such a weld protuberance is indicated at 12 in Fig. 4.

When the various members are placed together in their desired relative positions prior to welding, the protuberance 12 at the highest point of each bulge provided by a formation 11 engages the opposing surface of the member directly adjoining the sheet metal member, having the formation 11 in question, so that, as shown in Fig. 4, the planar portions of the adjoining members in the region of the formations 11, are spaced apart slightly by a small gap indicated at 13 in Fig. 4. The width of this gap depends, of course, on the height of the bulge and protuberance 12. Each of the spot welds 4 is formed where a respective protuberance 12 contacts the opposing member.

The members 2 and the carrying frame are capable of plastic deformation so that after the 3 1 GB2024053A 3 parts of the gate have been welded together, it is possible to achieve the desired wedge angle between the plane in which the rim 5 of one member 2 lies and that in which the rim 5 of the other member 2 lies, to the required accuracy and to achieve, to the desired accuracy, the spacing apart of the surfaces, facing away from each other of the rims 5 df the two members 2, etc. by pressing the gate in a jig press, providing respective pressing surfaces for engagement with the sealing surfaces of the members 2, provided by rims 5, and with the zones 3, so that deformation of said deformable regions is brought about to the extent necessary to achieve the desired dimensional accuracy.

Claims (12)

1. A component comprising a plurality of sheet metal members, including two such sheet metal members disposed face to face in contact with one another, said two members comprising a first and a second member of which the first member is welded to the second member at a point of contact between opposing surfaces of said two members, and at which point of contact a bulge on one of said opposing surfaces engages the other of said opposing surfaces to provide the point of contact, and wherein, in the region of each said point, at least one of the contacting members is deformable, said first member being welded to said second member at said point of contact by a spot weld formed at said point of contact.

2. A component according to claim 1 wherein said first member is welded to said second member by a plurality of spot welds each formed at a respective point of contact between a respective bulge on one of the two members and the opposing surface of the other of the two members.

3. A valve gate for a gate valve, the valve gate comprising a member constituting a car- rying frame and disposed between two dished sheet metal members providing respective sealing surfaces on opposite sides of the valve gate, each said dished member engaging the carrying frame at a plurality of points of contact between opposing surfaces of the respective parts, at each of which opposing surfaces a respective bulge on one of said opposing surfaces engages the other of said opposing surfaces, and wherein, in the region of each said point of contact at least one of the contacting parts is deformable, each said dished member being welded to the carrying frame by spot welds each formed at a respective said point of contact.

4. A valve gate according to claim 3 wherein each said bulge is formed in a said member of sheet metal, the member being deformable over the region of the bulge.

5. A valve gate according to claim 3 or claim 4 in which a weld protuberance is formed in the highest zone of each said bulge, said protuberance defining the respective point of contact and the respective spot weld being formed at the protuberance.

6. A valve gate according to any of claims 3 to 5 wherein said carrying frame comprises one or more sheet metal parts affording edges extending in the direction in which, in use, the valve gate is moved to open or close the valve in which the gate is fitted, said edges being formed as guide formations for cooperation with complementary formations on a gate valve body.

7. A valve gate according to any preced- ing claim, wherein said members of the gate are sheet metal parts formed by chipless machining.

8. A gate valve incorporating a valve gate according to any preceding claim.

9. A gate valve according to claim 8 incorporating a valve gate according to claim 6 and including a valve body provided with guiding formations cooperating with and complementary with said guide formations formed by said edges of the carrying frame, whereby said gate is guided for linear movement in the direction in which said edges extend to open and close the valve.

10. A valve gate for a gate valve, substan- tially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

11. A method of making a component comprising a plurality of sheet metal mem- bers, substantially as hereinbefore described.

12. Any novel feature or combination of features disclosed herein.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon) Ltd.-1 980. Published at The Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.