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Procedures are described for determining the losses in a liquid annular ring type of gas compressor. The development of a new type of partial bearing is discussed as well as the calibration of a testing motor and the construction and tests of a prototype. Data from experimental runs indicated that this low-cost, smooth-running, medium-speed (3000 rpm) compressor in a 3-hp size will develop 62% isothermal efficiency and deliver 53 cu ft/min of oil-free air at 4 psi.

Trans. of Inditserchaniye gazovogo kompressora vysokogo davleniya (Taking Indicator Diagrams of High Pressure Gas Compressors), (Russia), n1 p118-122, 1960.

The object of this program was to develop a Split-Stirling cycle cooler capable of producing .6 watts of refrigeration in a 120 F ambient with 28 Vdc input power of less than 90 watts. System weight objective is less than 3.5 pounds, separation between expander and compressor is 18 in. and the unit is to be nearly inaudible. One of the primary goals of the program was to develop a cooler that would be simple to construct and have low production cost. The approach was to develop a compressor incorporating linear motors and use this to actuate a miniature pneumatically actuated expander. The separate expander permits greater flexibility in incorporating it in an IR detector system and also permits isolation of the compressor vibration. The development of the compressor with linear motors proved to be very difficult. The program was carried to the point where enough of the problems were resolved so that a fair evaluation could be made of the future potential of this approach. Comparison of this compressor system with others under development at the contracting agency showed that it was not worth pursuing further development of this unit for this application. At this time the prototype unit demonstrated the practicality of the basic cycle and independent tests of the expander indicated it was operating well.

Development of a linear-motor resonant-piston compressor (LMRPC) for helium cryogenic refrigerators is under consideration by the U.S. Navy. A critical component of the LMRPC is the gas spring assembly used to obtain 60 hz resonance of the reciprocating compressor parts. Because of the size of the compressor, and the high level of compressor efficiency desired by the Navy, design of the gas spring is particularly critical with respect to minimizing gas spring leakage and thermal losses. The primary objective of the reported design and test program was to determine if a satisfactory gas spring can be developed for use in a prototype helium LMRPC. A further objective was to demonstrate that gas-lubricated bearings can be used to provide wear-free, contamination-free support of the reciprocating assembly of the LMRPC. (Modified author abstract)

An analytical procedure for determining the energy and volume characteristics of piston compressors operating with real gases is described. A differential equation of the change of gas pressure in a cylinder's obtained by using the first law of thermodynamics for bodies of variable mass. Formulas for calculating compressors delivery coefficient and indicated compressors power are derived., Trans. from Kholodilnaya Tekhnika i Teknologiya (USSR) p59-63 1970.

The program described in this report involved analysis, design and testing of a split-type, Vuilleumier cryogenic refrigerator capable of producing 2.0 watts at 77 K. The objective of the contract specifications was to arrive at a lightweight, self-running, silent refrigerator capable of being integrated into infrared imaging systems. Both analytical and experimental results showed taht the goals set for the cold side of the system i.e., the expander, could be achieved. However, difficulties encountered during the design of the system's hot side, i.e., the thermal compressor, indicated that the weight and self-running requirements for the system could not be met. As a result of these findings, the program was terminated prior to its last phase, i.e., the fabrication of final hardware. (Author)