Inexpensive formed-plastic vent cover has been developed that allows controlled purge of vent systems and also provides blowout protection. Cover can also be used in relief mode to allow normal system relief flows without disengaging from vent system. Cover consists of two parts made of plastics with varying densities to fit media used and desired pressures

Lee, A. C.

Mcdonald, M. D.

English

NASA Technical Reports Server

July 1972
NASA TECH BRIEF 
Marshall Space Flight Center
B72-10348 
H 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
conmercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
An Economical Vent Cover 
Periphery	 How it's done: Parting 
Plane The vent cover shown in the figure consists of two 
parts which may be constructed from a variety of plastics 
with varying densities to fit the media used and provide 
the desired blow-off of venting pressures. With the cover 
in the blow-off or controlled purge mode, the orifice 
allows low vent purge. In this mode, the cover can be 
blown off at a predetermined pressure. Also, the cover 
can be flipped to the opposite side and used at a different 
blow-off pressure. In general, blow-off pressures are 
determined by selection of the periphery stiffnesses on 
each side of the cover as well as by the particular choice 
of materials.	 - 
The cover can also be used in the relief mode to allow 
normal system relief flows without disengaging from the 
vent system. Relief pressures are determined by con-
figuration changes and different thicknesses and densities 
of the material used. 
The problem: 
In vent systems, control of undesirable air environ-
ment such as wind, rain, and humidity involves a wide 
variety of valve designs. Popular designs include flapper 
valves, swivel hoods, burst disc, spring loaded or weighted 
relief valves, and other combinations of these. Unfortu-
nately, most of these units have moving parts which are 
subject to seizures and require frequent maintenance. 
The solution: 
• An inexpensive formed-plastic vent cover has been 
developed that allows controlled purge of the vent 
systems and also provides blowout protection.
Category 07 
This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights. 
Feather 
Edge Seal 
Orifice Optional For 
Controlled Purge 
Blow-Off Characteristics 
Direction Of Flow
For Blow-Off
Or Controlled Purge 
Vent End (Reference) 
NOTE 
Vent Cover Applied To Only 
One End But May Be 
Reversed To Change Modes
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code A&TS-TU 
Huntsville, Alabama 35812 
Reference: B72-10348 
Patent status: 
No patent action is contemplated by NASA. 
Source: A. C. Lee and M. D. McDonald of
Astronautics Division of 
Mc Donnell Douglas Corp. 
under contract to
Marshall Space Flight Center 
(M FS-20692)
https://ntrs.nasa.gov/search.jsp?R=19720000347 2020-03-17T03:30:20+00:00Z


An economical vent cover

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