5-1/4 inches wide on the l-l/8-inch barrel. Each cap is machined 

 for two O-rings, type PRP-902-54 or National 622754. The O-ring 

 seal was designed for a 1,500 p.s.i.g. non-moving seal. Because 

 the inside diameter of the telemeter case did not conform to the 

 standard 0-ring size, it was necessary to recompute the groove, 

 ring clearance, ring cross section, and similar information. This 

 is for only one ring per end-cap; the second ring was added for 

 safety. 



(b) One end-cap top is blank to allow for the transducer 

 pivot clearance. The other end-cap top contains the depth and temper- 

 ature-sensing elements and the two feed-th roughs. 



The Depth-Sensing Assembly 



The depth -sensing assembly consists of a sealed passage con- 

 necting the two pressure potentiometers to the external water pressure. 

 The external exposed section is a rubber bulb served on a machined 

 nipple that is threaded and sealed in the end-cap. On the inside of 

 the telemeter case there is another threaded nipple in the end-cap 

 with a drilled head to take two pieces of 3/l6-inch-out side-diameter 

 (O.D.) annealed copper tubing. This tubing is silver-soldered to the 

 nipple, and the other ends have flare fittings that connect to the 

 pressure potentiometers. This system is filled with glycerine under 

 vacuum, and is, therefore, free of air bubbles. 



Fig. 7. Transmitter end bell showing rubber pump, metal thermistor 



housing and terminal seals. 



11 



