Ball valve and methods of fabrication

• US 4,960,262 A
• Filed: 07/18/1989
• Issued: 10/02/1990
• Est. Priority Date: 12/16/1982
• Status: Expired due to Fees

• Current Assignee: Sekisui Kagaku Kogyo Kabushiki Kaisha
• Original Assignee: Sekisui Kagaku Kogyo Kabushiki Kaisha
• Inventors: Takeda, Shinji, Hashimoto, Mitsuharu
• Primary Examiner(s): Fox, John C.
• Application Number:
  US07/381,918
• Time in Patent Office: 441 Days
• Field of Search: 251/315, 251/514, 137/315, 29/151.1 R
• US Class Current: 251/315.1
• CPC Class Codes: F16K 27/067 with spherical plugs
• CPC Class Codes: F16K 5/0668 Single packings
• CPC Class Codes: Y10T 137/0508 Ball valve or rotary ball valve
• CPC Class Codes: Y10T 137/6038 Particular valve seat or interface seal

Abstract

A ball valve and a method for fabricating this ball valve wherein a ball seat, formed of a synthetic resin, is mounted at each end of a flow passage in a ball of the valve. A sealing end portion of the ball seat contacts the spherical surface of the ball only in the closed position of the ball. In the open position, the lip falls within a recess surrounding the end of the flow passage in the ball. A gap of 0.3 to 0.7 mm is formed, in the open position, between the wall surface of the recess and the end of the lip. The end of the lip should fall, in the open position of the ball, about 0.2 mm inside an imaginary continuation of the surface of the ball at the recess.

Claims

1. A method for fabricating a ball valve, comprising the steps of:

inserting a ball and attached shaft into a pair of slide cores having portions extending into a flow passage in said ball;

disposing a ball seat at positions surrounding each end of said flow passage in said ball, each said ball seat comprising an annular body which is provided with a plurality of grooves formed in an outer peripheral portion and side portions thereof;

disposing an outer die around said pair of slide cores having a cavity therein dimensioned for forming a valve body, each said slide core having a seat holding portion for urging said ball seat toward said ball; and

injecting molten resin into a cavity between said outer die and said slide cores, and into said grooves, wherein each said ball seat has an annularly shaped lip extending toward said ball, and wherein a gap is formed between a surface of said lip facing away from said ball and an adjacent surface of each said slide core located radially inwardly of said seat holding portion.

2. A method for fabricating a ball valve, comprising the steps of:

inserting a ball and attached shaft into a pair of slide cores having portions extending into a flow passage in said ball;

disposing a ball seat at positions surrounding each end of said flow passage in said ball;

disposing an outer die around said pair of slide cores having a cavity therein dimensioned for forming a valve body, each said slide core having a seat holding portion for urging said ball seat toward said ball; and

injecting molten resin into a cavity between said outer die and said slide cores, wherein each said ball seat has an annularly shaped lip extending toward said ball, and wherein a gap is formed between a surface of said lip facing away from said ball and an adjacent surface of said slide core located radially inwardly of said seat holding portion.