Point of dispense heat exchanger for fluids

Abstract

A heat exchanger for fluids includes an elongated conduit. At least two spaced fluid passageways are defined in the conduit and extend longitudinally through the conduit from a first end thereof to a second end thereof. A heat transfer element thermally contacts a surface of the conduit to transfer heat to or from a fluid flowing through the at least two spaced passageways. The conduit can be unitary and of one piece. In one embodiment, the conduit can be a single crystal.

1 . A point of dispense heat exchanger assembly comprising:
 an elongated conduit body including:
 a first end, 
 a second end, 
 an outer periphery, 
 a first fluid passage defined in the conduit body and extending longitudinally in the conduit body from the first end thereof to the second end thereof, 
 a second fluid passage defined in the conduit body and extending longitudinally in the conduit body from the first end thereof to the second end thereof, 
 wherein the second fluid passage is spaced from and fluidically isolated from the first fluid passage; and, 
   a heat transfer element mounted to the outer periphery of the conduit body, wherein the heat transfer element thermally contacts the conduit body and is adapted to transfer heat to or from the conduit body by conduction.   
     
     
         2 . The assembly of  claim 1  wherein the conduit body is unitary and of one-piece and comprises a single crystal. 
     
     
         3 . The assembly of  claim 2  wherein the single crystal comprises sapphire. 
     
     
         4 . The assembly of  claim 1  wherein the heat transfer element comprises at least one of an electrical resistance heater cable mounted to the conduit body, a positive temperature coefficient (PTC) electrical heating element mounted to the conduit body, and a Peltier element mounted to the conduit body. 
     
     
         5 . The assembly of  claim 1  further comprising one of an electric cartridge heater located in a longitudinally extending central bore defined in the conduit body, or a cooling fluid flowing through the central bore. 
     
     
         6 . The assembly of  claim 1  wherein the conduit body includes a plurality of spaced fluid passages and a plurality of slots, wherein the heat transfer element comprises a PTC heating element and each slot accommodates a PTC heating element wherein each PTC heating element is located between two of the plurality of fluid passages. 
     
     
         7 . The assembly of  claim 1  wherein the conduit body is made of an electrically non-conducting material. 
     
     
         8 . The assembly of  claim 1  wherein the first and second fluid passages are non-circular in cross-section so as to promote a turbulent flow of a process fluid. 
     
     
         9 . The assembly of  claim 8  wherein the first and second fluid passages are one of elliptical, oval and polygonal in cross section. 
     
     
         10 . The assembly of  claim 9  wherein the first and second fluid passages are regular in cross section along a longitudinal axis of the conduit body. 
     
     
         11 . The assembly of  claim 1  wherein the conduit body is one of circular and polygonal in cross section. 
     
     
         12 . The assembly of  claim 1  further comprising a layer of a chemically inert material coating a surface of at least one of the first fluid passage and the second fluid passage. 
     
     
         13 . The assembly of  claim 12  wherein the coating material is one of an electrically insulative material, and an electrically conductive material. 
     
     
         14 . The assembly of  claim 1  wherein the first and second fluid passages extend generally parallel to each other. 
     
     
         15 . A method of controlling heat transfer to a process fluid flowing in a conduit disposed in a nozzle, comprising:
 providing a conduit body including a first end, a second end, an outer periphery and a longitudinal axis;   defining a central bore in the conduit body, the central bore extending along the longitudinal axis from the first end of the conduit body to the second end thereof;   defining a first process fluid passage in the conduit body, the first process fluid passage extending parallel to the longitudinal axis from the first end of the conduit body to the second end thereof;   defining a second process fluid passage in the conduit body, the second process fluid passage extending parallel to the longitudinal axis from the first end of the conduit body to the second end thereof wherein the first and second process fluid passages are fluidically isolated from each other and the central bore;   thermally contacting the outer periphery of the conduit body with a first heat transfer source;   thermally contacting the central bore of the conduit body with a second heat transfer source; and   regulating a transfer of heat to the process fluid flowing through the first and second fluid passages.   
     
     
         16 . The method of  claim 15  wherein the first heat transfer source comprises at least one of an electrical resistance heater cable, a positive temperature coefficient (PTC) heating element and a Peltier element. 
     
     
         17 . The method of  claim 15  wherein the second heat transfer element comprises an electric cartridge heater positioned in the central bore or a cooling fluid flowing through the central bore. 
     
     
         18 . The method of  claim 15  wherein a temperature of the process fluid is regulated to within a range of less than 1° C. 
     
     
         19 . The method of  claim 15  further comprising the step of causing a turbulent flow of the process fluid through the first and second fluid passages. 
     
     
         20 . A unitary, one-piece tubular fluid conduit for a point of dispense heat exchanger, comprising:
 a first end;   a second end;   an outer periphery;   a longitudinal axis;   a first process fluid passage defined in the conduit and extending in the conduit parallel to the longitudinal axis from the first end thereof to the second end thereof;   a second process fluid passage defined in the conduit and extending in the conduit parallel to the longitudinal axis from the first end thereof to the second end thereof;   a central bore defined in the conduit and extending along the longitudinal axis, wherein the first and second fluid passages are located radially outward of the central bore; and   wherein the first and second process fluid passages are non-circular in cross section to promote a turbulent flow of the process fluid.   
     
     
         21 . The conduit of  claim 20  wherein the first and second process fluid passages and the central bore are fluidically isolated from each other. 
     
     
         22 . The conduit of  claim 20  wherein the tubular conduit further comprises a thermally conductive and electrically isolating material. 
     
     
         23 . The conduit of  claim 20  wherein the tubular conduit comprises a single crystal. 
     
     
         24 . The conduit of  claim 23  wherein the single crystal is sapphire. 
     
     
         25 . The conduit of  claim 20  wherein the first and second fluid passages are elliptical or oval in cross section.