Heat pumps and fluid pumps therefor

Abstract

A fluid pump for pumping a fluid. One or more piston-cylinder arrangements each include a respective cylinder portion, a respective head portion and a respective piston portion together defining a respective pumping chamber. One or more connecting arrangements connect a crank member to the one or more piston-cylinder arrangements to drive the respective piston portion of each of the one or more piston-cylinder arrangements. A housing and the respective piston portion of each of the one or more piston-cylinder arrangements together house the crank member in an interior. The interior is sealed to capture blow-by. A transmission is arranged to transmit power, for rotating the crank member, into the housing magnetically, electrically or both.

1 . An apparatus comprising:
 a fluid pump, the fluid pump including:   one or more piston-cylinder arrangements each including a respective piston portion and a respective pumping chamber;   a crank member;   a housing; and   a transmission;   the housing together with the respective piston portion of each of the one or more piston-cylinder arrangements defining an interior in which the crank member is housed;   the interior being sealed to capture blow-by; and   the transmission being arranged to transmit power, for rotating the crank member, into the housing magnetically, electrically or both magnetically and electrically.   
     
     
         2 . The apparatus of  claim 1  wherein the transmission comprises a magnetic coupling including:
 a rotatable portion outside the housing; and 
 a portion inside the housing magnetically co-operable with, to be rotated by, the rotatable portion. 
 
     
     
         3 . The apparatus of  claim 2  including an electric motor for driving the rotatable portion. 
     
     
         4 . The apparatus of  claim 1  including an electric motor having a stator and a rotor, which are located inside the housing. 
     
     
         5 . The apparatus of  claim 4  wherein the transmission includes at least one wire for the electric motor and which enters the housing via a sealed aperture. 
     
     
         6 . The apparatus of  claim 1  wherein the transmission includes an electric motor comprising:
 a stator outside of the housing; and 
 a rotor inside the housing. 
 
     
     
         7 . The apparatus of  claim 1  including two or more of the piston-cylinder arrangements. 
     
     
         8 . The apparatus of  claim 7  including one or more connecting arrangements connecting the crank member to the respective piston portions, wherein the crank member and the one or more connecting arrangements are configured to move the respective piston portions in unison to hold substantially constant a volume of the interior. 
     
     
         9 . The apparatus of  claim 8  wherein the one or more connecting arrangements include a member having:
 two ends; and 
 a respective one of the piston portions at each of the ends. 
 
     
     
         10 . The apparatus of  claim 1  comprising reed valves each including:
 a respective port; 
 a respective ridge surrounding the respective port; and 
 a respective petal arranged to bear against the respective ridge to close the respective port; 
 wherein each respective one of the pumping chambers has a respective first of the reed valves defining one of an inlet to the respective pumping chamber and an outlet from the respective pumping chamber. 
 
     
     
         11 . The apparatus of  claim 10  wherein each respective ridge is shaped to contact a respectively corresponding respective petal along a respective line of contact not more than 0.5 mm thick. 
     
     
         12 . The apparatus of  claim 11  wherein each respective one of the pumping chambers has a respective second of the reed valves defining the other of the inlet to the respective pumping chamber and the outlet from the respective pumping chamber. 
     
     
         13 . The apparatus of  claim 10  wherein pistons have a combined displacement of not more than 10 cc (0.61 ci). 
     
     
         14 . The apparatus of  claim 1  wherein the apparatus is a heat pump and includes a fluid circuit; and the fluid pump is arranged to pump fluid about the fluid circuit. 
     
     
         15 . The apparatus of  claim 14  wherein the apparatus is a reverse cycle heat pump and includes a reversing valve arrangement; and
 the reversing valve arrangement includes:
 first-mode flow paths through which fluid flows when the pump is in the first mode of operation; 
 second-mode flow paths through which fluid flows when the pump is in the second mode of operation; 
 one or more valve elements; and 
 one or more electromechanical drives; and 
 
 the one or more electromechanical drives are arranged to electromechanically drive the one or more valve elements:
 from one or more respective first-mode positions at which the one or more valve elements occlude the second-mode flow paths; 
 to one or more respective second-mode positions at which the one or more valve elements occlude the first-mode flow paths; 
 
 to reverse a direction of flow about the fluid circuit and thereby switch from the first operating mode to the second operating mode. 
 
     
     
         16 . The apparatus of  claim 14  configured for evaporation of the fluid when the heat pump is in at least one operating mode of the heat pump, and wherein:
 the fluid circuit includes a fluid circuit portion; 
 the fluid circuit is configured for at least most of the evaporation to occur along the fluid circuit portion; and 
 the fluid circuit portion is arranged for the fluid to flow upwardly, or at least horizontally, along substantially all of the fluid circuit portion when the heat pump is in the at least one operating mode of the heat pump. 
 
     
     
         17 . The apparatus of  claim 16  wherein the fluid circuit is configured for at least 90% of the evaporation to occur along the fluid circuit portion. 
     
     
         18 . The apparatus of  claim 16  wherein the fluid circuit portion includes a serpentine conduit portion along which the fluid flows. 
     
     
         19 . The apparatus of  claim 14  including:
 a sensor to sense at least one of pressure or temperature, of the fluid on a high-pressure side of the fluid circuit; and 
 a control arrangement configured to vary a speed of the fluid pump in response to the sensor and in positive relation to the at least one of the pressure or temperature. 
 
     
     
         20 . The apparatus of  claim 19  wherein the fluid circuit comprises:
 a downstream heat exchanger downstream of a fluid pump; and 
 a refrigerant-cooling fan for driving air through the downstream heat exchanger; and 
 the control arrangement is configured to vary a speed of the refrigerant-cooling fan in response to the sensor and in positive relation to the at least one of the pressure or temperature. 
 
     
     
         21 . The apparatus of  claim 19  wherein:
 the fluid circuit comprises an upstream heat exchanger upstream of the fluid pump; and 
 the apparatus comprises:
 a refrigerant-heating fan for driving air through the upstream heat exchanger; and 
 a temperature sensor for providing an indication of a temperature of the material to be cooled by the heat pump; and 
 
 the control arrangement is configured to vary a speed of the refrigerant-heating fan in response to the temperature sensor and in positive relation to the temperature of the material to be cooled by the heat pump.