Standard high pressure valves are used in low pressure fluid system testing when a substantial system pressure increase is required. The flow-vs-valve stroke is matched with that of the valves being replaced. Some correction to the plug contour may be necessary

Bevan, A. F.

English

NASA Technical Reports Server

September 1966	 Brief 66-10416 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Matching Flow Characteristics of Standard Shutoff Valves 
Eliminates Need for Custom Fabricated Valves 
The problem: 
Frequently a low pressure fluid system is run 
through a test program near the upper limit. Test 
data may dictate that the system pressure be raised 
substantially so that a conplete set of higher pressure 
valves is needed. To accommodate the test data of the 
low pressure system, custom valves are usually fabri-
cated to match the flow characteristics of the valves 
to be replaced. This is a costly and time consuming 
procedure. 
The solution: 
Obtain standard off-the-shelf high pressure valves 
and plot the flow-vs-valve stroke with that of the 
valves being replaced. The precision of the flow 
characteristics may depend on the plug profiles, and 
some correction to the plug contour may be necessary. 
How it's done: 
Before any testing is done, make certain that both 
valves have the same type of plug flow characteristic 
(e.g., same rate of change in flow-vs-valve stroke). 
Conduct a water flow test on the valve to be replaced 
and a suitable replacement valve. Plot a curve of 
flow-vs-valve stroke for each valve and compare. The 
replacement valve must have a larger flow capacity
than the existing valve. Limit the stroke of the replace-
ment valve to provide the same maximum capacity as 
the existing valve. Restrict the flow of hydraulic 
fluid to the actuator in the ratio: 
Displaced Volume of Replacement Valve Actuator 
Displaced Volume of Existing Valve Actuator 
to assure that the replacement valve will have the 
same rate of opening or closing as the valve to be 
replaced. 
Note: 
Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B66-10416 
Patent status; 
No patent action is contemplated by NASA. 
Source: A. F. Bevan 
of North American Aviation, Inc. 
under contract to 
Marshall Space Flight Center 
(M-FS- 1069) 
Category 05 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000415 2020-03-11T17:36:49+00:00Z


Matching flow characteristics of standard shutoff valves eliminates need for custom fabricated valves

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server