O-ring, 5-1/4 



inch-ID, 3/32 



inch sectio 



This system should be suitable for capsules for cyclical service to 

 6,000 feet. The one failure at 3,000 psi serves to point up the fact that 

 the quality -control criteria applied to this type of glassware do not serve 

 to exclude potential rejects for this type of application. 



7. In this bearing— sealing system, two previous concepts were 

 combined. Aluminum washers similar to those described in No. 6 above 

 were fabricated. They differed in fabrication and treatment only in that 

 a recess was machined in one outside edge to provide an O-ring groove 

 when the assembly was made. (See Figure 29.) The O-ring in this groove 

 provided the watertight seal between the washer and the steel end-closure 

 disc. A second O-ring was placed in the groove in the glass pipe end flange. 

 This O-ring made a watertight seal between the washer and the glass pipe. 

 Molybdenum disulfide dry lubricant was applied to the areas of the washers 

 in contact with the steel end plates, and silicone grease was used to lubricate 

 the O-ring between the washer and the end plate, but no RTV silicone rubber 

 was used in this system. 



This system did not work satisfactorily at 3,000 psi. Each of the 

 specimen assemblies tested failed from cracks originating in the O-ring 

 groove of the glass pipe end flange — as in the case of the first gasket system 

 tested, which also used an O-ring in the glass pipe flange. While this system 

 very likely is satisfactory for cyclical service at some pressure less than 

 3,000 psi, it was not tested at lower pressures and its maximum useful 

 depth range is not known. 



8. These gaskets consisted of 

 1/4-inch-thick 60-shore-hardness neo- 

 prene sheet material cut into washers 

 and fitted into grooves in the steel end 

 plates. (See Figures 30 and 3T) The 

 contact area between the glass pipe 

 flanges and the rubber washer was 

 lubricated with silicone grease, and the 

 watertight seal was made after assembly 

 by applying RTV silicone rubber to the 

 joint between the glass and rubber. 



This system failed by cracking 

 and leaking in the transition area 

 between the pipe flange and the cylin- 

 drical pipe body after seven cycles to 

 3,000 psi. 



4-inch-ID X 6-inch-lc 

 Pyrex glass pipe 



compressed O-ring 4-1/2- 

 ID, 3/32-inch section 



>j, ; dry mo 



in.— ^r disulfid 



1/4-inch-thick 

 6061-T6 Al 



lybdenum 



stainless steel 

 type 316 



Figure 29. Experimental sealing and 

 bearing system utilizing 

 0-rings and an aluminum 

 washer interposed between 

 the glass pipe end flange 

 and the metal end-closure 

 plate. 



28 



