Burst disk/cutter, prewelded before assembly, eliminates external leakage into a vacuum annulus and provides a means for more accurate burst-pressure prediction. Two reverse buckling type configurations are described and test results are given

Martinez, J.

English

NASA Technical Reports Server

December 1970	 Brief 70-10583 
NASA TECH BRIEF	
_4k 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
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 progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Improved Burst Disk/Cutter Assembly 
Burst disks have been a frequent source of external 
leakage into a vacuum annulus when installed to 
prevent annulus overpressure. A burst disk/cutter 
assembly has been developed, prewelded before as-
sembly, which eliminates this failure condition, and 
provides a means for more accurate burst-pressure 
prediction. This device should be of use in medium and 
high-pressure systems which must be accurately con-
trolled. It should interest personnel in the fluid power 
and food processing industries. 
The reverse buckling burst disk has been established 
as the best unit for norispring relief of vacuum annulus 
overpressure. Two reverse buckling type configura-
tions were developed and thoroughly tested, which 
showed high reliability for field applications: the 
all-welded and the mechanically assembled unit which 
permits field replacement of the diaphragm. 
The all-welded unit was designed with a 304 stain-
less steel body and a nickel 200 or Inconel 600 dia-
phragm. Both diaphragm and cutter were coated with 
polytetrafluoroethylen e. Cutter-corrosion rate was 
evaluated to determine the effect of corrosion on the 
cutter-piercing point. Salt sprayed cutters showed that 
no corrosion had occurred on the coated samples. 
The reverse buckling disk design (the all-welded unit) 
proved to have a reliable lifetime of 5 or more years. 
The burst-disk assembly with a replaceable dia-
phragm combines features which permit hardware to 
be assembled in the field with little chance of damage 
and a very reliable permanent seal. The replaceable 
diaphragm units should provide the same extended 
service life predicted for the all-welded unit. The cutter
and bursting diaphragm are combined as a welded 
assembly that can be handled easily without damage. 
The profile of the burst-disk assembly is minimized to 
avoid damage after installation, thus decreasing costs. 
Sealing is accomplished by line contact of contoured 
conical surfaces with slightly different radii. A light 
film of high vacuum grease can be added to the sealing 
surface prior to assembly. With the grease and a grit 
free surface, all test units were disassembled and re-
assembled many times without leakage or other diffi-
culty. 
Notes: 
1. For information relating to the use of the burst 
disk for testing reverse buckling, see B70-10582. 
2. Requests for further information may be directed 
to:
Technology Utilization Officer 
Kennedy Space Center, Code AD-PAT 
Kennedy Space Center, Florida 32899 
Reference: 870-10583 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to: 
Patent Counsel 
Mail Code AD-PAT 
John F. Kennedy Space Center 
Kennedy Space Center, FL 32899 
Source: Joseph Martinez of

AMETEK/Straza
under contract to
Kennedy Space Center 
(KSC- 105 16) 
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.
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Improved burst disk/cutter assembly

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