Abstract: A vane-type double lobe hydraulic pump having a casing with a rotor having a plurality of slots with each slot mounting a vane for tracking of a surrounding cam ring and porting for pumping from both undervane and intervane pumping chambers. The cam ring has two generally elliptical sections of different contour whereby the volumes of fluid pumped by the vanes in coacting with one of said sections differ from the pumped volumes of the vanes when coacting with the other section. In one embodiment, there are four independent volume outputs while, in other embodiments, valve elements control the output of the pump whereby it may be the total of the pumped fluid or lesser amounts including only the volume pumped by the vanes in coacting with one of said cam ring sections or only part thereof.

Abstract: A pair of helical screw rotary hermetic compressor units are connected in parallel across common suction and discharge manifolds. The discharge manifolds open to each unit casing well above the level of accumulated oil within the bottom of the hermetic casings acting as oil sumps. Oil bleed lines are provided for the casings which open to the casing interior at oil bleed ports at the normal level of accumulated oil. The bleed lines are of small diameter and open directly to the discharge manifold at points downstream of the connection between the discharge manifold and the hermetic casing. Excessive accumulation of oil within one of the hermetic compressor casings causes the oil to bleed through its bleed line under a small pressure differential to the discharge manifold for redistribution to the remaining compressors.

Abstract: A symmetrical, twin centrifugal pump includes a pair of valves mounted about a common shaft. The valves are capable of independent operation thus allowing either or both of the pump elements to operate. A key is also mounted to the shaft to allow overall regulation of the pump by selectively impeding the flow of liquid from the pump inlet to pump outlet.

Abstract: A multiple displacement pump system utilizing a single fixed displacement pump having pumping elements providing both first and second sets of pumping chambers. Circuit means having a fluid utilization conduit provides for delivery of fluid to said fluid utilization conduit which is either the sum of fluid delivered from both sets of pumping chambers or from only one set of pumping chambers. Additionally, the circuit means includes various alternate forms of control dependent upon pressure in a part of the system or on speed of a mechanism utilizing the pumped fluid to establish conditions wherein fluid delivered by the system is at either a desired flow rate or within a range of flow rates at different pressures.

Abstract: A method and apparatus for controlling a multiple-plant gas-producing facility which is subject to wide variations in the demand for its output. The invention is particularly applicable to an oxygen-producing facility for a steelmaking operation in which there are two independently operable oxygen-producing plants. It is impractical to shut down an oxygen-producing plant when its output temporarily is not needed. During periods of reduced demand conventional practice is to operate one plant at its normal rate to supply the needed oxygen and operate the other plant at a reduced rate and waste excess oxygen which cannot be liquefied and stored. The invention provides a way of combining the outputs of two plants, whereby both plants can operate at reduced rates during periods of reduced demand, and large scale waste is avoided.

Abstract: A multiple displacement pump system and method utilizing a single fixed displacement pump having pumping elements providing both first and second sets of pumping chambers. Circuit means having a fluid utilization conduit provides for delivery of fluid to said fluid utilization conduit which is either the sum of fluid delivered from both sets of pumping chambers or from only one set of pumping chambers. Additionally, the circuit means includes various alternate forms of control dependent upon pressure in a part of the system or on speed of a mechanism utilizing the pumped fluid to establish conditions wherein fluid delivered by the system is at either a desired flow rate or within a range of flow rates at different pressures.