SENSITIVE CHECK VALVE

• US 3,770,009 A
• Filed: 12/29/1971
• Issued: 11/06/1973
• Est. Priority Date: 12/29/1971
• Status: Expired due to Term

• Current Assignee: Richard William Miller
• Original Assignee: Richard William Miller
• Inventors: Miller, Richard W.
• Primary Examiner(s): Nilson, Robert G.
• Application Number:
  US05/213,383
• Time in Patent Office: 678 Days
• Field of Search: 137/516.25,516.27,516.29,535,538,540,515,515.3,515.5,515.7 251/368,543.19
• US Class Current: 137/543.19
• CPC Class Codes: F16K 15/026 the valve member being a movable body around which the medium flows when the valve is open
• CPC Class Codes: Y10T 137/7856 Valve seat formed on or carried by a coupling element
• CPC Class Codes: Y10T 137/7937 Cage-type guide for stemless valves

Abstract

A check valve characterized by a lightweight valve member and a weak biasing spring such that it opens and reseats with a low differential pressure of only about three ounces per square inch thereacross, preferably less. The check valve may be used in high pressure applications, yet has structure and low engineering tolerances such that it may have the desired flow with very low differential pressure drop across the valve member, and it may be employed in applications such as welding or cutting torches, without inducing flutter into the flame of the torch. In specific embodiments, the check valve is lightweight for balancing of the torch, and is color coded for use with a specific gas.

Claims

1. A check valve for applications, such as with torches, where opening and closing at low differential pressure and elimination of flutter are requirements, comprising:

a. a tubular body having longitudinally extending bores at each end and a valve chamber intermediate each end;

the inlet bore having an internal diameter smaller than the internal diameter of the valve chamber said body defining at the end of said inlet bore adjacent said valve chamber a seat for a nose portion of a valve member;

b. a valve member in said chamber in said valve body, said valve member having a nose portion having resilient seal means for sealingly seating against said seat when reverse flow is attempted through said check valve;

said resilient seal means being soft enough to seal against said seat at low differential pressures of no more than three ounces per square inch;

said valve member being formed of a lightweight material having a density of less than 2.5 grams per cubic centimeter such that it has a low inertia and having an elongate cylindrical base portion that conformingly fits within said chamber with a clearance that is sufficiently small along its entire length that flutter of the lightweight valve member is prevented, said valve member being movable longitudinally of said chamber in response to a low differential pressure less than said three ounces per square inch thereacross and having a plurality of elongate passageways extending substantially longitudinally of said elongate base portion;

said plurality of passageways in said base portion having a total cross sectional area that is open for flow that is at least equal to the cross sectional area of said inlet bore such that very little pressure drop is experienced across said valve member in the open position;

said longitudinally extending passageways extending through said elongate base portion at an angle of less than 30* with respect to the longitudinal axis of said valve member and having substantially uniform diameter throughout and terminating at the base end of said valve member opposite said nose portion without abruptly changing diameter within said valve member such that minimal tubulence is created in the flow of a fluid therethrough; and

c. weak biasing means biasing said valve member toward said seat by acting on said base end;

said valve member and said weak biasing means being chosen such that said valve member will open and will seat with a differential pressure thereacross in the respective directions of no more than three ounces per square inch;

whereby said check valve can be employed and alleviate the problems with flutter, such as flame flutter in a torch.

2. The check valve of claim 1 wherein said valve member is mAde of a thermoplastic material and said weak biasing means comprises a weak spring that is chosen such that said valve member will open and seat at about one ounce per square inch pressure differential in the respective directions.

3. The check valve of claim 2 wherein said seal means has a durometer hardness of about 70 for effecting a seal with said seat at the low differential pressure effecting reseating of said valve member.

4. The check valve of claim 2 wherein said tubular valve body has a two-piece configuration, wherein said valve chamber is dimensioned such that its diameter has an engineering tolerance within the range of only 0.000 to -0.005 inch;

and wherein said valve member is dimensioned such that its diameter is within an engineering tolerance of 0.000 to +0.003 inch to alleviate the problems with oscillation of the valve member in said valve chamber.

5. The check valve of claim 2 wherein said body is made of green anodized aluminum.

6. The check valve of claim 2 wherein said body is made of red anodized aluminum.