Pump for hot and cold fluids

A positive displacement hydraulic pump for use with super-cooled and super-heated fluids of low lubricity and viscosity and for use with such fluids at a temperature between the temperatures of said super-heated and super-cooled fluids, said hydraulic pump comprising an inner rotor, a ring-shaped outer rotor having a plurality of internal teeth and being formed with an outer cylindrical surface, said inner rotor having a plurality of external teeth formed thereon in meshing engagement with said internal teeth of said outer rotor, said external teeth formed on said inner rotor being at least one less in number than the number of internal teeth formed on said outer rotor, said inner rotor having its axis of rotation positioned at a fixed eccentricity from the axis of rotation of said outer rotor and said external teeth of said inner rotor and said internal teeth of said outer rotor having generated tooth profiles for maintaining continuous fluid tight contact during rotation of said inner and outer rotors, a ring-shaped stationary support housing for said inner and outer rotors, an inner cylindrical surface formed in said support housing, a plurality of roller bearings interposed between and in direct contact with said inner cylindrical surface of said support housing and the outer cylindrical surface of said outer rotor, a pair of end plates fixed to said support housing and cooperating with the latter to enclose said inner and outer rotors, a drive shaft extending through said pair of end plates for driving connection with said inner rotor, one of said pair of end plates having a fluid inlet port formed therein and the other of said pair of end plates having a fluid outlet port formed therein, said inlet port and said outlet port being located relative to said inner and outer rotors so that rotation of said inner rotor and said outer rotor creates an expanding chamber adjacent said inlet port for drawing fluid therein while simultaneously creating a contracting chamber adjacent said outlet port for forcing the fluid through said outlet port at a high pressure, said support housing and said inner and outer rotors being made of the same metallic material and having essentially the same width dimension along the rotational axis of said drive shaft so that the thermal expansion of said support housing and of said inner and outer rotors while pumping super-heated fluid and the thermal contraction of said support housing and of said inner and outer rotors while pumping super-cooled fluid does not adversely affect the end-clearance between the end plates and the inner and outer rotors to an extent where the efficiency of the pump would differ if it were pumping fluid at a temperature of 70 degrees Fahrenheit, and said roller bearings being made of a metallic material different than the metallic material of said support housing and said inner and outer rotors so as to avoid material transfer and molecular bonding between the outer rotor and the support housing.

A multi-stage positive displacement hydraulic pump for use with super-cooled and super-heated fluids of low lubricity and viscosity and for u se with such fluids at a temperature between the temperatures of said super-heated and super-cooled fluids, each stage of said hydraulic pump comprising an inner rotor, an outer rotor and a ring shaped stationary support housing circumferentially surrounding said inner rotor and said outer rotor, said outer rotor having a plurality of internal teeth and being formed with an outer cylindrical surface, said inner rotor having a plurality of external teeth formed thereon in meshing engagement with said internal teeth of said outer rotor, an inner cylindrical surface formed in said support housing, a plurality of roller bearings interposed between and in direct contact with said inner cylindrical surface of said support housing and the outer cylindrical surface of said outer rotor, a pair of end plates fixed to said support housing at each stage of said pump and cooperating with the support housing to enclose said inner and outer rotors, a drive shaft extending through said pair of end plates for driving connection with said inner rotor at each stage of said pump, one of said pair of end plates having a fluid inlet port formed therein and the other of said pair of end plates having a fluid outlet port formed therein, said inlet port and said outlet port being located relative to the associated inner and outer rotors so that rotation of said inner rotor and said outer rotor creates an expanding chamber adjacent said inlet port for drawing fluid therein while simultaneously creating a contracting chamber adjacent said outlet port for forcing the fluid through said outlet port at a high pressure, said support housing and said inner and outer rotors at each stage of said pump being made of the same metallic material and having essentially the same width dimension along the rotational axis of said drive shaft so that the thermal expansion of said support housing and of said inner and outer rotors while pumping super-heated fluid and the thermal contraction of said support housing and of said inner and outer rotors while pumping super-cooled fluid does not adversely affect the end-clearance between the end plates and the inner and outer rotors to an extent where the efficiency of the pump would differ if it were pumping fluid at a temperature of 70 degrees Fahrenheit, and said roller bearings being made of a metallic material different than the metallic material of said support housing and said inner and outer rotors so as to avoid material transfer and molecular bonding between said outer rotor and said support housing.