There were two possible disadvantages to the design: (1 ) opening and closing 

 of a vessel was time consuming and (2) the 0-ring extruded when operated 

 to any reasonable pressure and required replacement after each test'. These 

 disadvantages are not severe because the system is for long term operation, 

 not day-to-day operation. A typical pressure vessel consisted of two 32-inch- 

 diameter steel flanges as shown in Figure B-1 . The conical surfaces of the 

 flanges were machined to a 32 rms finish. The three vessels had through-hole 

 nominal diameters of 4, 6, and 8 inches. 



Figure B-1. Typical pressure vessel flanges with an 8-inch minor diameter viewport. 



High-Pressure Pump 



The high-pressure pump was an air-driven double-acting piston type 

 rated for 20,000 psi. Tubing made of 1/4-inch-diameter, 316 stainless steel 

 connected the pump to the accumulator. 



Accumulator 



The air/water accumulator provided a means of storing energy in the 

 high-pressure system to maintain a constant pressure in the vessels. The 

 vessels were all connected to a common manifold, thus, pressure cycling 

 was identical for all three vessels. 



42 



