Apparatus For Control of Fluid Temperature

Abstract

The present invention relates to a device for controlling the temperature of a fluid by heating and/or cooling. It has a reciprocating, displacement type pumping arrangement which propels fluid from an outlet to an outlet via a conditioning chamber in which fluid temperature control is carried out by means of a thermoelectric heat pump which is preferably of Peltier type.

1 . A device for controlling fluid temperature, comprising a fluid inlet, a fluid outlet, and a reciprocating, displacement type pumping arrangement comprising a piston and cylinder which is arranged to draw the fluid in through the inlet and to exhaust it through the outlet, wherein the pumping arrangement communicates with one of the inlet and the outlet via a conditioning chamber through which the fluid passes on its way from the inlet to the outlet and in which fluid temperature control is carried out, the device further comprising at least one solid state thermo-electric heat pump having a first side which is thermally coupled to fluid within the conditioning chamber and a second side which is arranged to transmit heat to a sink or to receive heat from a source, so that by means of the thermo-electric heat pump the temperature of the conditioning chamber wall, and of the fluid within the conditioning chamber, is controllable wherein the cylinder is divided by the piston into first and second working chambers so that piston motion in one direction causes fluid to be drawn into the first working chamber and to be exhausted from the second working chamber, and piston motion in the opposite direction causes fluid to be exhausted from the first working chamber and to be drawn into the second working chamber, the unit further comprising a valve arrangement, which selectively connects whichever working chamber is at any moment exhausting fluid to the pump outlet, thereby providing mono-directional flow through the outlet. 
   
   
       2 . A device as claimed in  claim 1 , comprising shaped heat exchange features within the conditioning chamber having surfaces exposed to fluid within the conditioning chamber to exchange heat with the fluid, the heat exchange features also being thermally coupled to the thermoelectric heat pump to exchange heat with that. 
   
   
       3 . A device as claimed in  claim 1  wherein the conditioning chamber has a thermally conductive wall whose interior is exposed to the fluid, the thermoelectric heat pump being mounted to and thermally coupled to the exterior of said conditioning chamber wall. 
   
   
       4 . A device as claimed in  claim 2  wherein the heat exchange features comprise fins. 
   
   
       5 . A device as claimed in  claim 4  wherein the heat exchange features are integrally formed with the conditioning chamber wall. 
   
   
       6 . A device as claimed in  claim 4  wherein the fins extend along a fluid flow direction within the conditioning chamber. 
   
   
       7 . A device as claimed in  claim 4  wherein the pump comprises a piston and a cylinder. 
   
   
       8 . A device as claimed in  claim 7  wherein the cylinder is circular and the conditioning chamber is a substantially annular or semi-annular cavity around and concentric with the cylinder. 
   
   
       9 . A device as claimed in  claim 7  wherein the aforementioned thermally conductive conditioning chamber wall is disposed around at least part of the cylinder, the conditioning chamber being defined between an outer surface of the cylinder and an inner surface of the conditioning chamber wall. 
   
   
       10 . A device as claimed in any preceding claim, further comprising a heat sink arranged to receive heat from the second side of the thermo-electric heat pump. 
   
   
       11 . A device as claimed in  claim 7  further comprising a heat sink which is arranged to receive heat from the second side of the thermo-electric pump and which forms a shell surrounding the conditioning chamber wall. 
   
   
       12 . A device as claimed in  claim 1  comprising two end plates wherein each endplate provides for inlet of fluid into the respective cylinder working chambers and comprises a conduit connecting each working chamber to it's associated conditioning chamber. 
   
   
       13 . A device as claimed in  claim 12 , wherein each working chamber communicates with a respective one-way valve which is arranged to exhaust fluid from the chamber and is connected to the outlet. 
   
   
       14 . A device as claimed in  claim 13  wherein each chamber additionally communicates with a respective one-way valve which is arranged to let fluid into the chamber. 
   
   
       15 . A device as claimed in  claim 12 , comprising first and second conditioning chambers which are communicable respectively with the first and second working chambers within the cylinder. 
   
   
       16 . A device as claimed in  claim 15  wherein the first and second conditioning chambers together form an annulus surrounding the cylinder. 
   
   
       17 . A device as claimed in  claim 16  wherein the first and second conditioning chambers are both defined between the cylinder and the conditioning chamber wall. 
   
   
       18 . A device as claimed in  claim 17  wherein the first and second conditioning chambers are separated from each other by a dividing wall in a plane containing the cylinder axis. 
   
   
       19 . A device as claimed in  claim 17 , wherein the pumping arrangement comprises a lead screw which threadedly engages with the piston in order to reciprocally drive it. 
   
   
       20 . A device as claimed in  claim 17  which is an air conditioning device. 
   
   
       21 . A bed or a seat comprising an air conditioning device as claimed in  claim 20 . 
   
   
       22 . A refrigeration unit provided with a device according to  claim 20 . 
   
   
       23 . A method for controlling fluid temperature in a device comprising a cylinder divided by a piston into first and second working chambers which working chambers communicate with one or more conditioning chambers which have at least one solid state thermo electric device associated therewith, wherein:
 i. the piston motion in one direction causes fluid to be drawn into the first working chamber and to be exhausted from the second working chamber; and   ii. the piston motion in the opposite direction causes fluid to be exhausted from the first working chamber and to be drawn into the second working chamber; and in which   iii. a valve arrangement selectively circulates fluid mono directionally from a fluid inlet to a fluid outlet via the conditioning chamber.   
   
   
       24 . A method as claimed in  claim 23  wherein the fluid goes through multiple cooling or heating phases by fluid recirculation. 
   
   
       25 . A method as claimed in  claim 23  wherein the residence time of the fluid is increased by increasing the fluid path length within the conditioning chamber.