Fluid pressure apparatus

• US 3,948,083 A
• Filed: 12/31/1974
• Issued: 04/06/1976
• Est. Priority Date: 10/26/1970
• Status: Expired due to Term

• Current Assignee: Westinghouse Brake & Signal Holdings Limited (Siemens AG)
• Original Assignee: Westinghouse Brake & Signal Holdings Limited (Siemens AG)
• Inventors: Wickham, David John
• Primary Examiner(s): Swisher, S. Clement
• Application Number:
  US05/537,663
• Time in Patent Office: 462 Days
• Field of Search: 73/39, 73/40, 73/40.5
• US Class Current: 73/39
• CPC Class Codes: B60T 13/26 Compressed-air systems
• CPC Class Codes: B60T 17/228 for railway vehicles
• CPC Class Codes: G01F 1/34 by measuring pressure or differential pressure
• CPC Class Codes: G01M 3/2807 for pipes G01M3/2892, G01M3/30 take precedence

Abstract

A fluid pressure comparison apparatus including a pressure responsive member displaceable by the difference between two pressure sources being compared to vent fluid from one of the sources, when its pressure is greater than the other, through a port whose aperture is varied by the displacement of the pressure responsive member. The flow of vented fluid is measured in one of many possible ways to determine the excess pressure. The measurement may be displayed on an indicator or applied to control associated equipment. Various arrangements embodying the apparatus may be used for flow indication, flow control, leakage detection and indication and as warning or control equipment. The pressure responsive member is shown as a nylon reinforced rubber diaphragm but the nature of the member will depend on the absolute as well as the relative values of the pressures compared.

Claims

1. Leak detection apparatus including a fluid-tight vessel internally divided into a first and a second chamber by a flexible pressure responsive member, the first chamber having a first port for a first fluid pressure signal, the second chamber having a second port for a second fluid pressure signal, and the second chamber having a third port, the pressure responsive member being operable to effect closing of said third port when the force exerted on the pressure responsive member including the pressure in the first chamber exceeds the opposing force exerted on the member including the pressure in the second chamber, the third port being vented through a restricted passage to atmosphere, the fluid pressure in said passage from said second chamber depending on the degree of closure of the third port, the second port being connected to a reference pressure reservoir, and means for utilizing a pressure signal generated upstream of the restricted passage to provide an indication of fluid pressure leakage via the first port.

2. Apparatus as claimed in claim 1 wherein said first port is connected with a fluid pressure conduit comprising a railway brake pipe at a first point, and said brake pipe includes a valve relatively upstream from said first point so as to permit isolation of a downstream portion of said pipe for measurement of leakage therefrom.

3. Apparatus as claimed in claim 2 wherein said first point is connected to said second chamber and said reservoir through a check valve such that fluid can flow from said brake pipe through said check valve to said reservoir and to said second chamber, but not vice versa.

4. Apparatus as claimed in claim 3 wherein said first point and said reservoir are connected to said second chamber through said second port.

5. Apparatus as claimed in claim 1 further comprising a railway fluid pressure brake pipe, said first port being connected to a first point on said brake pipe, the second chamber having a fourth port, said fourth port being connected to a second point on said brake pipe upstream from a first flow restrictor, which is itself upstream from said first point, through a second flow restrictor of similar flow characteristics to said first flow restrictor such that the flow through one stimulates the flow through the other under the same conditions, a valve in said brake pipe upstream of said first point, and a further valve in the connection between said second point and said fourth port, whereby with said valve and further valve open fluid conditions in said passage from said third port are indicative of the flow in said brake pipe, and with said valve and further valve closed fluid conditions in said passage are indicative of the fluid pressure leakage from said brake pipe.

6. Apparatus as claimed in claim 5 wherein said first point is connected to said second port and said reservoir through a check valve.

7. Apparatus as claimed in claim 5 wherein said means for utilizing a pressure signal is a pressure gauge calibrated to indicate both flow through the brake pipe and leakage from the brake pipe.

8. Apparatus as claimed in claim 1 wherein said means for utilizing a pressure signal is a pressure gauge.

9. Apparatus as claimed in claim 1 wherein said pressure responsive member is a flexible diaphragm with a surface portion deformable to itself close said third port.