CHANGING BIAS CHECK VALVE

• US 3,789,874 A
• Filed: 07/13/1972
• Issued: 02/05/1974
• Est. Priority Date: 07/13/1972
• Status: Expired due to Term

• Current Assignee: David A. Hills
• Original Assignee: David A. Hills
• Inventors: Hills, David A.
• Primary Examiner(s): Cline, William R.
• Application Number:
  US05/271,625
• Time in Patent Office: 572 Days
• Field of Search: 137/527,527.4,527.6,530,531 251/298,299,303,251,262,263
• US Class Current: 137/527
• CPC Class Codes: F16K 1/24 with valve members that, on opening of the valve, are initially lifted from the seat and next are turned around an axis parallel to the seat
• CPC Class Codes: F16K 15/033 spring-loaded
• CPC Class Codes: F16K 31/52441 with a pivoted disc or flap
• CPC Class Codes: Y10T 137/7898 Pivoted valves
• CPC Class Codes: Y10T 137/7907 Varying effective lever arm

Abstract

A check valve in which clapper bias torque diminishes as the clapper opens, a clapper support carrying pivotally mounted thereon a clapper assembly and (pivotally mounted intermediately thereof) a cam arm, a compression spring extending between the clapper support and one end of the cam arm causing the other end of the cam arm to impose a bias force on the clapper assembly, the bias force being imposed along a plane defined by a transverse line near said other end of the cam arm and a transverse line on the clapper assembly. In a preferred embodiment the force is imposed from a stainless steel roller rotatably mounted in said other end of the cam arm to a plastic roller rotatably mounted at the downstream end of the clapper assembly.

Claims

1. A check valve comprising:

a clapper support, a clapper assembly rotatably mounted on said clapper support, a cam arm rotatably mounted intermediately thereof on said clapper support, a compression spring extending between said clapper support and a first end of said cam arm, and means securing said cam arm toward the other end thereof to said clapper assembly so that force is applied from said cam arm to said clapper assembly through a plane passing through an axis transverse of said cam arm toward said other end thereof and through an axis transverse of said clapper assembly wherein a cylindrical cam surface at said other end of said cam arm is urged against a cylindrical surface carried by said clapper assembly owing to the force on said cam arm from said compression spring.

2. The check valve of claim 1 in which said cylindrical cam surface is the surface of a cylindrical element carried by said cam arm.

3. The check valve of claim 2 in which said cylindrical element is rotatably mounted on said cam arm for rotation about said axis transverse of said cam arm.

4. The check valve of claim 1 in which said cylindrical surface is the surface of a cylindrical clapper assembly element carried by said clapper assembly.

5. The check valve of claim 4 in which said cylindrical clapper assembly element is rotatably mounted on said clapper assembly for rotation about said axis transverse of said clapper assembly.

6. The check valve of claim 1 in which said cylindrical cam surface is the surface of a cylindrical element rotatably mounted on said cam arm for rotation about said axis transverse of said cam arm, said cylindrical surface is the surface of a cylindrical clapper assembly element rotatably mounted on said clapper asSembly for rotation about said axis transverse of said clapper assembly, and one of said cylindrical elements is plastic and the other thereof is stainless steel.

7. The check valve of claim 6 in which said clapper assembly cylindrical element is plastic.

8. The check valve of claim 6 in which said cam arm carries at said first end a spring engaging bushing engaging said compression spring, said spring engaging bushing being pivotally mounted on said cam arm to pivot about an axis transverse thereof.