Seal device for gate valve

• US 4,562,992 A
• Filed: 10/10/1984
• Issued: 01/07/1986
• Est. Priority Date: 12/26/1983
• Status: Expired due to Term

• Current Assignee: Fuji Eizai Kabushikikaisha, Ishimaru Hajime
• Original Assignee: Fuji Seiko KK, Hajime Ishimaru
• Inventors: Ishimaru, Hajime, Onoda, Mutsuro, Sugisaki, Kenzaburo
• Primary Examiner(s): Weakley, Harold W.
• Application Number:
  US06/659,412
• Time in Patent Office: 454 Days
• Field of Search: 251/158, 251/159, 251/167, 251/171, 251/172, 251/173, 251/328, 251/368, 267/74
• US Class Current: 251/159
• CPC Class Codes: F16K 3/20 by movement of the seats
• CPC Class Codes: F16K 3/207 by means of hydraulic forces

Abstract

A seal device for a gate valve is disclosed, in which annular members facing the front and rear surfaces of a gate valve member having a through hole are coupled to a valve cage by inner and outer bellows, each of the annular members has an annular recess formed on the side facing the gate valve member and closed by an annular mirror surface finished thin plate secured by welding to an opening thereof, the individual bellows are elongated by fluid under pressure supplied into annular spaces defined by the inner and outer bellows, and the annular mirror surface finished thin plates are strongly urged against the gate valve member by the pressure of the fluid forced from the annular spaces into the annular recesses. Edge portions of the annular mirror surface finished thin plates are to be very firmly mounted to the annular members, and the mechanical strength of the thin plates is to be increased. The two annular mirror surface finished thin plates are to be simultaneously brought into contact with the front and rear surfaces of the gate valve member, and are to be urged against the gate valve member with a uniform pressure over the entire circumference.

Claims

1. A gate valve sealing arrangement, comprising in combination:

(a) a valve cage (4) with an outer structure and a hollow cylindrical inner chamber, said inner chamber having coaxial rear and front openings (1,

     2), said rear and front openings defining a flow path, also, outer wall members (17) around the chamber;

(b) a gate valve member (6), with parallel flat front and rear surfaces, said gate valve member (6) being disposed to move in a direction normal to the defined flow path substantially across the center of said chamber, also, said gate valve member (6) having a through aperture (5);

(c) annular members (10), one annular member being disposed on each side of the gate valve member (6) and spaced apart from said outer wall members (17), the annular members (10) each having an annular recess (9) with an open side facing the gate valve member (6);

(d) inner and outer bellows (7,

     8) in the valve cage (4) on opposite sides of the gage valve member (6) around the outer structure of the valve cage (4), said inner and outer bellows (7, 8,) being spaced apart from each other and having inner and outer ends, the inner ends being coupled to the annular member (10), the outer ends being connected to the outer wall members (17) so that the outer wall members (17), the annular members (10), and the inner and outer bellows (7,

     8) define annular open spaces (12) around the valve cage outer structure;

(e) first and second aligned retaining means (37, 16, 32,

     33) intermediate said inner and outer bellows, the first retaining means being connected to said outer wall members (17), the second retaining means being connected to said annular members (10), inwardly biasing spring means (15) held by said retaining means, stoppers (38) partially extending from one of said members (10,17) towards the other of said members preventing the collapse of the annular members (10) towards the outer wall members (17), a communication aperture (13) in each of said annular members extending from its annular recess (9) to the annular open spaces (12), pressure application ports (14) in the valve cage (4) open to the annular open spaces (12);

(f) a thin plate (11) having an annular mirror surface finish on the side of each annular member (10) facing the gate valve member (6), said thin plate (11) closing the open side of said annular recess (9); and

,

(g) thick edge portions (19) around the annular mirror surface finish of the thin plate (11) so affixing the thin plate to the annular member (10) that the total surface of the mirror surface finish thin plate (11) closing the opening of the annular recess (9) is parallel to the flat front and rear surfaces of the gate valve member (6).

2. A sealing arrangememt for a gate valve according to claim 1 wherein said spring means (15) consist of a plurality of tension coil springs in a spaced-apart arrangement in the circumferential direction of the annular space (12), the ends of each of said coil springs being connected to said retaining means, the first of said retaining means having a tenson adjustment threaded rod (16) secured to said coil spring end, and threaded into the wall member (17) with a tension adjustment nut (18) threaded onto said threaded rod (16).