REFRIGERATION SYSTEM 



A refrigeration system was necessary in this study to aid in simulating 

 actual environmental conditions. Located on the pressure vessels were Plate- 

 Coil heat transfer units as shown in Figure B-2a. The single, embossed units 

 were rolled to the vessel diameter to insure adequate heat transfer between 

 the vessels and the units. Two units which were connected together by a 

 jumper hose were necessary for one vessel. A heat transfer cement, Thermon 

 T-3, was used between the vessel and heat transfer units to increase the over- 

 all heat transfer coefficient. Sheets of an elastomeric insulation, Armaflex, 

 were used on top of the heat transfer units as shown in Figure B-2b. Glycol 

 brine was circulated through the refrigeration system. Cooling was provided 

 by a 5-ton-capacity air-cooled chiller. Temperature measurements were 

 taken at both the inlet and outlet of the chiller. 



INSTRUMENTATION SYSTEM 



Dial indicators, as shown in Figure B-3, were utilized on each of the 

 six viewport faces to measure absolute displacement of the center of the 

 face with respect to the pressure vessel. Lufkin dial indicators with gradua- 

 tions of 0.001 inch were used. The averages of the displacement readings 

 for the three pairs of viewports in the pressure vessels were calculated and 

 are presented in Figure 7 of this report. 



Pressure gages with a range of 5,000 psi were the high-pressure 

 measuring system, while a 50-psi gage was used on the no-load part of the 

 cycle. Here it was necessary to maintain a 1 to 5-psi load to keep the view- 

 port in position. 



VIEWPORTS 



The seven viewports in this study (including one used in theO-ring 

 test) were machined from a 4-foot by 5-foot by 4-inch cast sheet of 

 Plexiglas G acrylic plastic. The viewports were rough machined and then 

 annealed in accordance with the manufacturer's recommendations^ ^ 

 as follows: 



Section Annealing ^. Cooling 



-T-u- , -r Time 



Thickness Temp Rate 



(in.) (°F) '^'' (°F/hr) 



4 175 22 5 



43 



