VALVE BODY FOR NON-SLIDING GATE VALVE

Abstract: A non-sliding gate valve used in a high vacuum according to this invention consists of a valve casing (1) and a valve body (2) provided displaceably in the valve casing (1) so as to open and close valve openings (11) formed therein, and the valve body (2) is composed of a pair of a valve plate (301) and a counter plate (302) provided in parallel with each other in a mutually opposed state in the valve casing (1) so as to close a valve seat (17) formed therein, a pair of inner support members (32) of metal discs disposed in parallel in a space between these plates (301, 302), an outer support member (33) of an annular metallic material disposed on the outer side of the inner support members (32) and a pair of annular elastic connecting members (34) disposed in a mutually spaced-apart and radially extending state between the outer circumferential surface of the inner support members (32) and the inner circumferential surface of the outer support member (33). The valve plate (301) and counter plate (302) are sealed and firmly held on the opposed inner support members (32), while the inner and outer support members (32), (33) are sealed and firmly held at their outer and inner circumferential surfaces with and on the inner and outer circumferential portions of the annular elastic connecting member (34). The outer radially extending surfaces of the annular elastic connecting members (34) are provided with at least one annular projection (340) formed perpendicularly to and concentrically with the same surfaces. A sealed space (35) is formed among the inner support members (32), annular elastic connecting members (34) and outer support member (33).

Description: The present invention relates to a valve body of a non-sliding gate valve for high vacuum use comprising a valve housing having a valve seat surrounding a valve opening formed in said valve housing, said valve body being adapted to close or open said valve seat, said valve body comprising a paired valve plate and a counter plate spaced apart with a gap being left therebetween, said valve and counter plates each having an outer diameter sufficient to close said valve seat formed in said valve housing and each having its center line arranged in line with a center line of said valve opening and being parallel with said valve seat at a distance therefrom, respectively, an outer support member made of an annular metal body arranged between said valve and counter plates in the direction of said center line of said valve opening, and a pair of annular elastic connecting sheets made of thin metal connecting said valve and counter plates to said outer support member, a sealed space being defined in the gap between said valve and counter plates, said connecting sheets and said outer support member, means being provided for delivering a pressurized fluid into said sealed space in order to urge said plates against their respective seat. A valve body of this structure is known from US-A-2476711. It has strong valve and counter plates. The outer support member is situated mainly radially inside the outer periphery of the valve and counter plates and flat annular elastic connecting sheets are sealingly secured at their outer peripheries to the outer peripheries of the valve and counter plates and at their inner peripheries to the inner periphery of the outer support member. The valve is closed by admission of pressurized fluid into the sealed inner space of the valve body. For opening the valve the pressurized fluid is withdrawn from the sealed space and the valve and the counter plates are urged to be retracted from their seats as a result of application of an outer pressure on them from the pressurized fluid prevailing at the valve opening. In this case the elastic connecting sheets follow the movement of the valve and counter plates to restore their original positions. The elasticity is not great enough to force the plates to retract to their original positions without the outer fluid pressure. Therefore, this gate valve is not applicable for high vacuum use. A non-sliding gate valve for high vacuum use is also known from Japanese laid-open patent publication No. 63-254275. It has a constitution as described hereafter in connection with Fig. 2 and 3. The gate valve comprises a hollow box-like valve housing 1 having substantially an elliptical configuration when viewed in an elevational view and of a shallow depth when viewed from the side, and a valve body 2 disposed therein and having substantially a circular plate-like shape, the valve body 2 being adapted to close or open the valve opening 1₁ formed axially in the valve housing 1. On the outside of the valve housing 1, on its top wall 3 a pair of brackets 4₁, 4₂ are vertically secured thereto with a gap being left therebetween in the longitudinal direction of the top wall 3 (see Fig. 3), a bearing member 5 having substantially an inversed U-shaped configuration being disposed within the gap between the brackets 4₁ and 4₂ with its leg members 5₁ and 5₂ being pivoted to the confronting brackets 4₁ and 4₂, respectively, by pivot 6₁ and 6₂, respectively. The central web portion 5₃ of the bearing member 5 has a hollow bar-like rod 7 centrally secured near its upper end portion, the valve body 2 being radially secured to the rod 7 at its lower end. Swingably secured on the outside of the valve housing 1 is an air cylinder 8 at its piston rod end so that its center line orthogonally intersects the longitudinal axis of the valve housing 1 (see Figs. 2), whereby the end of the piston rod of the air cylinder 8 is swingably connected to the rod 7 near its upper end portion and above the bearing member 5 having an inverted U-shaped configuration. Thus, by actuating the air cylinder 8 to extend or retract the piston rod, the rod 7 is swung together with the bearing member 5 secured thereto about the pivots 6₁, 6₂ relative to the brackets 4₁, 4₂ secured to the valve housing 1. Therefore, the valve body 2 secured to the rod 7 at its lower end portion can be selectively swung to a position indicated at the solid lines in Fig. 2 where it closes the valve opening 1₁, or to a position indicated at the phantom lines in Figs 2 where it opens the valve opening 1₁. As shown in Fig. 3 the valve body 2 comprises a valve plate 10, a counter plate 11, both arranged in line with the center line of the valve opening 1₁, and a metallic bellows 13 sealingly connecting the valve plate 10 and the counter plate 11 at their opposing outer peripheries. The valve plate 10 and the counter plate 11 are respectively made of a circular metallic plate of substantially identical dimensions, and respectively constituted from a pressure-resisting metallic concave dish-like plate 14, 15, a sealed space 16 being defined by the valve plate 10, counter plate 11, and metallic bellows 13, and is adapted such that when pressurized air is supplied to it from the outside through a passage 7₀ formed in the rod 7 to which the valve valve body 2 is secured at its upper portion the metallic bellows 13 is urged to expand against its elasticity so that the valve plate 10 and the counter plate 11 are respectively urged against the valve seat 17 formed around the valve opening 1₁ and against the wall 18 formed within the valve housing 1 opposite the valve opening 1₁ which constitutes a counter plate receiving seat for the counter plate 1₁, thereby the counter plate 11 acting to assist the valve plate 10 being strongly urged against the valve seat 17 to sealingly close the valve opening 1₁. Inversely, in order to open the valve opening 1₁ from this closed state, upon discharge of the pressurized fluid from the sealed space 16, the bellows 13 contracts due to its elasticity, resulting in the separation of the valve plate 10 from the valve seat 17, and, in this case, the separation of the counter plate 11 from the counter plate receiving seat 18 is assisted by the action of a compressive coil spring 9 disposed outside the valve housing 1. It was found that the last described gate valve could well achieve the aimed objects, but it was also found that when the valve body 2 was to be opened the valve plate 10 was not necessarily opened smoothly by the contractive force generated by the elasticity of the metallic bellows 13. Therefore, in order to prevent such a difficulty a compression spring means 20 was provided so as to connect the valve and counter plates 10, 11 together. The spring means 20, however, brings about another problem in that it complicates the constitution of the gate valve, and as the spring means 20 is exposed within the valve housing 1 it affects the fluid flowing within the valve housing 1. Accordingly it is an object of the present invention to provide an improved valve body for a non-sliding gate valve for high vacuum use in which a strong contractive force is provided by the annular elastic connecting sheets. In accordance with the present invention this object is achieved in that each of said valve and counter plates are made of a circular thin metal plate, in that said valve body further comprises a pair of inner support members arranged within said gap between said valve plate and said counter plate so as to be concentric with them and in parallel with each other at a distance, each of said inner support members having an outer diameter smaller than the outer diameter of said valve and counter plates, in that said outer support member is arranged radially outside said inner support members and has an inner diameter larger than the outer diameter of said valve and counter plates with a width substantially equal to the sum of the thicknesses of said inner support members, in that said pair of annular elastic connecting sheets are arranged between the outer peripheries of said inner support members and the inner periphery of said outer support member, in that said valve and counter plates are sealingly connected to said inner support members, in that the outer peripheries of said inner support members and the inner periphery of said outer support member are sealingly secured to said annular elastic connecting sheets at their inner and outer peripheries, respectively, and in that each of said annular elastic connecting sheets is formed with at least one concentric corrugation on the surface thereof and perpendicular thereto, said sealed space thus being formed between said inner support members, said annular elastic connecting sheets and said outer support member. The invention will be hereinafter more fully described with reference to the accompanying drawings in which: Fig. 1 is a vertical sectional view of a principal portion of one embodiment of the present invention; Fig. 2 is an elevational view of a gate valve previously proposed by the present applicant, partially in section; and Fig. 3 is a vertical sectional view of the gate valve shown in Fig. 2. The gate valve shown in Fig. 1 comprises a valve housing 1 and a valve body 2 disposed within the valve housing 1 adapted to open or close the valve opening 11 axially formed in the valve housing 1. Although not precisely shown in Fig. 1, as shown in Figs. 2 the valve housing 1 has substantially an elliptical configuration when viewed in a front elevational view, while the valve body 2 has substantially a circular configuration when viewed in a front elevational view as shown in Figs. 2 by the solid lines, and is so constituted that it occupies within the substantially elliptical valve housing 1 a position confronting the valve opening 1₁ in preparation for closing it as shown at the solid lines in Figs. 2, and a position displaced from the valve opening 1₁ as shown by the phantom lines in Figs. 2 after being swung from the first position in a plane bisecting the depth of the valve housing 1. When the valve body 2 swings between the two positions the valve body 2 is in a contracted state as shown in Fig. 1 so that there is no relative sliding motion between the valve seat 17 and the counter plate receiving seat 18 formed in parallel with the valve seat 17 within the valve housing 1 during the swing movement of the valve body 2 between the above two positions. The valve body 2 in accordance with the present invention comprises, as shown in Figs. 1, a valve plate 30₁ and a counter plate 30₂, respectively confronting the valve seat 17 and the counter plate receiving seat 18 formed in the valve housing 1 so as to be coaxial with the valve seat 17 as well as the counter plate receiving seat 18 and in parallel with each other in a spaced relationship, the valve plate 30 ₁ and the counter plate 30 ₂ being paired and each made of substantially a thin annular metallic plate. The surfaces of the valve plate 30 ₁ and the counter plate 30₂ respectively confronting the valve seat 17 and the counter plate receiving seat 18 are arranged, respectively, so as to be in parallel with the seats 17, 18, respectively, and are respectively provided with an annular seal element 31₁ and support elements 31₂ so as to sealingly abut the valve seat 17 and be firmly supported on the counter plate receiving seat 18, respectively. Coaxially disposed between the valve plate 30₁ and the counter plate 30 ₂ are a pair of inner support members 32 each made of a thick circular plate-like metal having an outer diameter somewhat larger than the inner peripheries of the plates 30₁, 30₂, the confronting surfaces of the inner support members 32 elongating perpendicular to the center line X-X of the valve opening 1₁ with a gap being left therebetween, and the opposite surfaces are respectively formed with two concentric inner and outermost annular projections 32₂ and 32₃, respectively, each of the inner annular projections 32₂ being sealingly connected such as by welding at its outer surface to the valve plate 30₁ and counter plate 30₂ at their inner peripheries, respectively. Coaxially arranged around the outer peripheries of the outermost annular projections 32₃ of the inner support members 32 is a metallic annular outer support member 33 having an inner diameter larger than the outer diameter of the valve plate 30₁ and counter plate 30₂ with an annular gap being left therebetween, the outer support member 33 having a substantial thickness and a width substantially equal to the sum of the thicknesses of the inner support member 32. Thus, it will be appreciated that there are radial annular gaps left between the outer peripheries of the outer annular projections 32₃ of the inner support members 32 and the inner periphery of the outer support member 33, respectively. These radial annular gaps are respectively sealingly closed by a pair of annular elastic connecting sheets 34 each made of a thin metal sheet and arranged in parallel with each other at intervals with their outer flanges 34₁ and inner flanges 34₂ being sealingly connected to the inner periphery of the outer support member 33 and the outer peripheries of the outer annular projections 32₃ of the inner support members 32, respectively. Each of the annular elastic connecting sheets 34 is formed with at least one concentric corrugation 34₀ (two in the embodiment shown) perpendicular to the surface of the connecting sheet 34. Such an annular elastic connecting sheet 34 made of a thin metal sheet with concentric annular corrugations 34₀ reveals extremely high elasticity, in particular superior restoring force from the selection of its material and the adoption of a suitable forming process therefore. Thus, between the confronting surfaces 32₁ of the pair of the inner support members 32 and between the confronting surfaces of the pair of annular elastic connecting sheets 34 a sealed space 35 is formed, into or out of which a pressurized fluid such as compressed air can be supplied or discharged through a fluid passage 36 radially formed through the outer support member 32, whereby, when the pressurized fluid is supplied within the sealed space 35 the confronting circular-plate like surfaces 32₁ of the inner support members 32 are pushed outwards by this pressurized fluid, resulting in elastic deformation of the annular elastic connecting sheets 34 so that the valve plate 30₁ and the counter plate 30₂ fixedly secured to the outer peripheries of the inner support members 32 are urged towards the valve seat 17 and the counter plate receiving seat 18 respectively formed in the valve housing 1. In this case, the annular elastic sheets 34 themselves are also pushed outwards by the pressurized fluid so that they freely deform outwards against their elasticity, assisting in the movements of the inner support members 32 in that direction. Accordingly, the valve plate 30₁ and the counter plate 30₂ abut the valve seat 17 through the annular seal element 31₁ and the counter plate receiving seat 18 through the support elements 31₂, perfectly closing the valve opening 1₁. Inversely, when the pressurized fluid is discharged through the fluid passage 36 from the inside of the sealed space 35 the annular elastic connecting sheets 34 return to their original states due to their own elasticity, so the inner support members 32, and thus the valve plate 30₁ and counter plate 30₂ fixedly secured to them resume their original states as shown in Fig. 1 to open the valve opening 1₁. As apparent from the foregoing, the valve body in a gate valve, in particular a non-sliding gate valve for high vacuum use in accordance with the present invention differs from the known gate valve such as previously proposed by the present applicant in that the opening or closing, in particular opening of the valve plate 30₁ and the counter plate 30₂ does not need the action of compression spring 20 as shown in Fig. 3 which are required in the previously proposed gate valve. Instead only the strong elastic restoring force exhibited by the annular elastic connecting sheets 34 is required. Further, in the previously proposed gate valve, in order to open or close the valve body by a single bellows an additional mechanism was provided, but in the gate valve in accordance with the present invention such a mechanism is eliminated and instead the valve plate 30₁ and the counter plate 30₂, each having the same constitution, perform the action of such a mechanism, making the opening or closing of the valve opening 1₁ more rapid, and the constitution of the gate valve itself is greatly simplified. It should be noted at this point, that although in the present invention, the annular elastic connecting sheets 34 play a large part in revealing such excellent effects, they fundamentally differ in constitution, operation and effects from the metallic bellows 13 as used for carrying out the same operation in the previously proposed invention as shown in Fig. 3. This is because the metallic bellows 13 is shaped so that a number of corrugations are formed in the wall of a cylindrical tube made of thin metal sheet, or a number of annular thin metal sheets are superposed and adjoining sheets are welded together at their inner or outer peripheries so as to form a tubular body, the cylindrical body or tubular body thus formed performing its objective action by the elongation or contraction of the body itself, whereas, the annular elastic connecting sheets 34 in the present invention represent respectively annular shapes, each annular sheet being formed with at least one concentric corrugation 34₀ perpendicular to the surface of the plate, and two of the sheets 34 thus formed are arranged in parallel with each other with a gap being left therebetween, where the annular elastic connecting sheets 34 can reveal such excellent properties as specific elasticity, particularly strong restoration force after having been elastically deformed, etc. In contrast, generally known bellows can not reveal such characteristic operations and effects comparable to those in the annular elastical connecting sheets in accordance with the present invention. Further, since the annular elastic connecting sheets used as one of the essential constitutional elements in the present invention have specific elastic properties, it is not only applicable to a valve body in a gate valve, but it is also widely applicable to various apparatuses which need to reveal operations and effects similar to those in the present valve body.

Claims: A valve body (2) of a non-sliding gate valve for high vacuum use comprising a valve housing (1) having a valve seat (17,18) surrounding a valve opening (1₁) formed in said valve housing (1₁), said valve body (2) being adapted to close or open said valve seat (17,18), said valve body (2) comprising a paired valve plate (30₁) and a counter plate (30₂) spaced apart with a gap being left therebetween , said valve and counter plates (30₁,30₂) each having an outer diameter sufficient to close said valve seat (17,18) formed in said valve housing (1) and each having its center line arranged in line with a center line (X-X) of said valve opening (1₁) and being parallel with said valve seat (17,18) at a distance therefrom, respectively, an outer support member (33) made of an annular metal body arranged between said valve and counter plates (30₁,30₂) in the direction of said center line (X-X) of said valve opening (1₁), and a pair of annular elastic connecting sheets (34) made of thin metal connecting said valve and counter plates (30₁,30₂) to said outer support member (33) , a sealed space (35) being defined in the gap between said valve and counter plates (30₁,30₂), said connecting sheets (34) and said outer support member (33) , means (36) being provided for delivering a pressurized fluid into said sealed space (35) in order to urge said plates (30₁,30₂) against their respective seat (17,18), characterized in that each of said valve and counter plates (30₁,30₂) are made of a circular thin metal plate, in that said valve body (2) further comprises a pair of inner support members (32) arranged within said gap between said valve plate (30₁) and said counter plate (30₂) so as to be concentric with them and in parallel with each other at a distance , each of said inner support members (32) having an outer diameter smaller than the outer diameter of said valve and counter plates (30₁,30₂), in that said outer support member (33) is arranged radially outside said inner support members (32) and has an inner diameter larger than the outer diameter of said valve and counter plates (30₁, 30₂) with a width substantially equal to the sum of the thicknesses of said inner support members (32), in that said pair of annular elastic connecting sheets (34) are arranged. between the outer peripheries of said inner support members (32) and the inner periphery of said outer support member (33), in that said valve and counter plates (30₁,30₂) are sealingly connected to said inner support members (32) , in that the outer peripheries of said inner support members (32) and the inner periphery of said outer support member (33) are sealingly secured to said annular elastic connecting sheets (34) at their inner and outer peripheries, respectively, and in that each of said annular elastic connecting sheets (34) is formed with at least one concentric corrugation (34₀) on the surface thereof and perpendicular thereto, said sealed space (35) thus being formed between said inner support members (34) , said annular elastic connecting sheets (34) and said outer support member (33). A valve body as claimed in claim 1, wherein said valve and counter plates (30₁,30₂) respectively have an annular shape and are sealingly connected at their inner diameter portion to said inner support members (32) at their outer periphery portions.

Inventors: HAYASHI YUZO - SUWA-CHO, IRIE NORIKIMI - KITAZAWA -CHOM, SAWA TOSHIO - HIGASHI MITSUKI, HAYASHI, YUZO 11-19, SUWA-CHO, IRIE, NORIKIMI 24-8, KITAZAWA 1-CHOME, SAWA, TOSHIO 102-50, HIGASHI MITSUKI
Applicants: IRIE KOKEN KK, IRIE KOKEN KABUSHIKI KAISHA
Application year: 1990
Main classification: F16K3
IPC codes: F16K51, F16K3