Lightweight, removable, sealed joint access door for a spherical or semispherical pressure vessel containing cryogenic materials uses a joint overlock design to take the shear and moment loads. Oversize bolt holes are used so that the attaching bolts are in tension only

Englehart, R. C., Jr.

English

NASA Technical Reports Server

Eii 
December 1965
	 Brief 65-10402 
NASA TECH BRIEF	 jI 
NASA Tech Briefs are issued by the Technology Utilization Division to summarize specific 
technical innovations derived from the space program. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical information, Springfield, Virginia, 22151. 
Lightweight Door Seals Cryogenic Container
Against Diaphragm Type Loading 
FIMMMUIRM
The problem: To design a lightweight, removable, 
sealed joint access door for a spherical or semispheri-
cal pressure vessel containing cryogenic materials. The 
door must accept the same diaphragm type loading 
as the pressure vessel skin and the joint must be capa-
ble of handling large temperature and load deflections. 
Prior devices have depended on precision machined 
bolts and bolt holes designed to carry tension, shear. 
and moment loads. This places severe requirements 
on manufacturing and installation techniques. 
The solution: An access door that incorporates a 
joint overlock design and oversize bolt holes so that 
the attaching bolts are in tension only. Shear and 
moment loads are taken by the joint's overlock design. 
How it's done: The access door is held in place and 
compresses the seal by means of tension bolts in re-
cessed sockets. The door bolt holes are oversize and 
the door has an internal shoulder or ridge that is 
slightly smaller than a mating shoulder at the peri-
phery of the pressure vessel opening. All horizontal
loads caused by pressure are transmitted through 
the joint in shear and the tension bolts are relieved 
of this loading by the oversize holes in the door. As 
pressure or thermal loads decrease, the joint tends to 
open up but good sealing is retained by action of the 
tension bolts on the seal. 
Notes: 
1. This innovation improves reliability, appreciably 
reduces manufacturing costs and weight, and pro-
vides a direct seal pressure joint with flexibility and 
strength. 
This concept is adaptable to all types and shapes of 
pressure vessels and is especially useful where large 
thermal and pressure deflections are involved. 
Inquiries concerning this invention may be di-
rected to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama. 35812 
Reference: B65-10402
(continued overleaf) 
Now
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.
https://ntrs.nasa.gov/search.jsp?R=19650000399 2020-03-11T17:25:24+00:00Z
Patent status: NASA encourages the immediate 
commercial use of this invention. Inquiries about 
obtaining rights for its commercial use may be made 
to NASA, Code AGP, Washington, D.C., 20546. 
Source: Royal C. Englehart, Jr. 
of North American Aviation, Inc., 
under contract to 
Marshall Space Flight Center 
(M - FS-476) 
Brief 65-10402	 Category 05


Lightweight door seals cryogenic container against diaphragm type loading

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