Heat exchanger, heat exchanger tube and methods of making and using same

Abstract

A heat exchanger tube is disclosed herein comprising a first portion, a twisted portion, and a transition portion between the first portion and the twisted portion. The transition portion includes a reinforcing sleeve. A heat exchanger formed from the tube and a method of forming a heat exchanger tube also are disclosed. The tube is useful in making a heat exchanger configured to operate at high pressures without mechanical failure.

1 . A heat exchanger tube comprising a first portion, a twisted portion, and a transition portion between the first portion and the twisted portion, the transition portion including a reinforcing sleeve. 
   
   
       2 . The heat exchanger tube of  claim 1 , wherein the reinforcing sleeve is positioned over the transition portion. 
   
   
       3 . The heat exchanger tube of  claim 2 , wherein the first portion comprises straight tube material. 
   
   
       4 . The heat exchanger tube of  claim 1 , wherein the first portion, twisted portion and transition portion comprise titanium. 
   
   
       5 . The heat exchanger of  claim 4 , wherein the reinforcing sleeve comprises titanium. 
   
   
       6 . A heat exchanger comprising an outer tube and an inner tube defining an annular opening therebetween, the inner tube including a first portion, a twisted portion, and a transition portion between the first portion and the twisted portion including a reinforcing sleeve formed thereon, the inner tube being configured to withstand a hydrostatic test pressure of at least 2600 psig for at least 2 minutes without mechanical failure. 
   
   
       7 . The heat exchanger of  claim 6 , wherein the heat exchanger is configured to receive a first fluid in the inner tube and second fluid in the annular portion, and the reinforcing sleeve enables to heat exchanger to operate with a pressure difference of at least 300 psi between the first and second fluids. 
   
   
       8 . The heat exchanger of  claim 6 , wherein the inner tube is configured to withstand a hydrostatic test pressure of at least 3000 psig for at least 2 minutes without mechanical failure. 
   
   
       9 . The heat exchanger of  claim 6 , wherein the outer tube is coiled. 
   
   
       10 . The heat exchanger of  claim 6 , wherein the heat exchanger contains a refrigerant fluid in the inner tube and a second fluid in the annular space between the inner tube and outer tube. 
   
   
       11 . The heat exchanger of  claim 10 , wherein the refrigerant is at least one of R410A, R-410b, R-417a, R-134a and R-407a. 
   
   
       12 . The heat exchanger of  claim 10 , wherein the second fluid comprises water. 
   
   
       13 . The heat exchanger of  claim 10 , wherein the second fluid comprises chlorinated water. 
   
   
       14 . A heat pump comprising the heat exchanger of  claim 6 . 
   
   
       15 . A heat exchanger comprising an outer tube and an inner tube defining an annular opening therebetween, the inner tube including a first portion, a twisted portion, and a transition portion between the first portion and the twisted portion including a reinforcing sleeve formed thereon, the inner tube being configured to pass a fatigue test of 250,000 cycles between 118 psig and 418 psig at a rate of 0.5 cycles/second without mechanical failure. 
   
   
       16 . The heat exchanger of  claim 15 , wherein the heat exchanger is configured to receive a first fluid in the inner tube and second fluid in the annular portion, and the reinforcing sleeve enables to heat exchanger to operate with a pressure difference of at least 300 psi between the first and second fluids. 
   
   
       17 . A method of making a heat exchanger tube comprising:
 forming a inner tube comprising a first portion, a twisted portion, and a transition portion between the first portion and the twisted portion, and   forming a reinforcing sleeve over the transition portion.   
   
   
       18 . The method of  claim 17 , further comprising disposing the inner tube and reinforcing sleeve in an outer tube to form an annular opening between the inner tube and the outer tube. 
   
   
       19 . The method of  claim 17  wherein the inner tube and the reinforcing sleeve comprise titanium. 
   
   
       20 . The method of  claim 17  wherein the first portion, twisted portion and transition portion are formed from a continuous segment of tube material. 
   
   
       21 . The method of  claim 17  wherein the transition portion includes a section of straight tube material and a section of twisted tube material, and the reinforcing sleeve is configured to protect a portion of the section of twisted tube material from fluid impingement.