m. DESCRIPTION OF APPARATUS 



A. HIGH -PRESSURE EQUIPMENT 



1 . Operation 



The high-pressure equipment was designed and constructed by Harwood 

 Engineering Company, Inc., Walpole, Massachusetts. The assembled equipment 

 is shown in Figures 1, 1, and 3, and a schematic representation of it is given in 

 Figure 4. We can best describe this equipment by describing its operation, which 

 is as follows . 



Close drain valve 4 (see Figure 4) and the valve on handpump 3 . Open 

 needle valve 5 and the valves on handpumps 1 and 2, and pump with handpump 3 

 until the hydraulic fluid begins to escape from release valve 7 . This operation 

 brings the piston of the intensifier to the bottom of its stroke and brings the pres- 

 sure on the high-pressure side of the intensifier to 10, 000 psi. Next, close the 

 valves on handpumps 1 and 1, and open the valve on handpump 3 . Raise the piston 

 of the intensifier by pumping first handpump 1 until the desired pressure is ob- 

 tained. (Release valve 6 releases at 10, 000 psi.) If pressures higher than 10, 000 

 psi are desired, handpump 2 is used. Handpump 1 was included in the system be- 

 cause of its greater effectiveness in the lower pressure range . Hydraulic fluid 

 escapes from release valve 6 when the Bourdon-type gauge (10, Figure 4) on the 

 low-pressure side of the intensifier reads approximately 10, 000 psi. The pres- 

 sure multiplication factor of the intensifier is 16. The pressure on the high- 

 pressure side of the intensifier is measured by a manganin cell" and recorded on 

 a Foxboro Dynalog recorder (11, Figure 4). 



When the intensifier piston reaches the top of its stroke, the pressure 

 on the high-pressure side will cease to increase as the pressure on the low-pres- 

 sure side increases . In order to continue to increase the pressure on the high- 

 pressure side of the intensifier, a second piston stroke is required. This stroke 

 is accomplished by slowly opening the valve on handpump 2, opening the needle 



*Manganin is a Cu-Mn-Ni alloy whose electrical resistivity is pressure -sensitive, 

 The manganin element was calibrated by Harwood Engineering Company by a 

 dead weight testing technique, and the pressure reading is accurate to within 

 0.5 to 1% (at full scale deflection). A novel feature of the present apparatus is 

 the location of the manganin element in a fitting rather than in its own separate 

 pressure vessel. This arrangement, while making the manganin element more 

 vulnerable to damage, simplifies construction and appreciably reduces the ex- 

 pense of the equipment , 



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S- 7001-0307 



