Design Approach 



The first instrument housing designed to meet the above 

 specifications was essentially the same as the housing shown 

 on Page 43 of (2). It consisted of two tapered end caps, 

 each housing a mechanical cable lock, threaded onto a central 

 instrvunent section. The electrical leads from the cable were 

 sealed by a potting compound, which served as an electrical 

 insulator as well as a watertight seal. The threaded section 

 was sealed by neoprene 0-rings. On each end of the central 

 section, a phenolic plate, containing the female receptacles 

 for the electric f eed- through s, was held in place by snap 

 rings. The center section had an inside diameter of approxi- 

 mately three inches, a wall thickness of 0.345 inch, and a 

 length of 12 inches. The overall length of the assembled 

 housing was 28 inches. 



Development 



To test the housing, a fixture (Figure 1-5) was designed 

 v*iich, v>^en enclosed in a pressure tank, would subject the 

 housing to tensile, as well as hydrostatic load, thus paral- 

 leling operational conditions. 



The first instrument housing (2) tested in this manner 

 failed, due to the porosity in the compound potted around 



I.X9 



