Steam-to-gas heat exchanger

Abstract

A heat exchanger for generating steam from water is disclosed. The exchanger comprises a first heat exchanging chamber, a second heat exchanging chamber and an array of heat pipes which are arranged to extend from within the first heat exchanging chamber to within the second heat exchanging chamber. The first heat exchanging chamber comprises a distributed inlet for passing the water into the first chamber from a distributed position around the chamber and an outlet through which the steam can exit the first chamber, the water being arranged to pass over the portion of the heat pipes which extend within the first chamber. The second heat exchanging chamber comprises an inlet for receiving a gas into the chamber and an outlet through which the gas can exit the second chamber, the gas being arranged to pass over the portion of the heat pipes which extend within the second chamber.

What is claimed is:  
     
         1 . A heat exchanger for generating steam from water, the exchanger comprising a first heat exchanging chamber, a second heat exchanging chamber and an array of heat pipes which are arranged to extend from within the first heat exchanging chamber to within the second heat exchanging chamber;
 the first heat exchanging chamber comprising an inlet for receiving water into the chamber and an outlet through which the steam can exit the first chamber, the water being arranged to pass over the portion of the heat pipes which extend within the first chamber;   the second heat exchanging chamber comprising an inlet for receiving a gas into the chamber and an outlet through which the gas can exit the second chamber, the gas being arranged to pass over the portion of the heat pipes which extend within the second chamber;   wherein the inlet to the first chamber comprises a distributed inlet for passing the water into the first chamber from a distributed position around the first chamber.   
     
     
         2 . A heat exchanger according to  claim 1 , wherein the distributed inlet is arranged to extend above the portion of heat pipes which extend within the first chamber. 
     
     
         3 . A heat exchanger according to  claim 1 , wherein the distributed inlet comprises a distributed nozzle arrangement. 
     
     
         4 . A heat exchanger according to  claim 3 , wherein the distributed nozzle arrangement comprises a tube which extends around the first chamber and which comprises a plurality of apertures formed therein though which the water can pass. 
     
     
         5 . A heat exchanger according to  claim 1 , wherein the first heat exchanging chamber further comprises a sensor for monitoring the level of water therein. 
     
     
         6 . A heat exchanger according to  claim 1 , wherein the portion of at least one of the heat pipes within the first heat exchanging chamber comprises a fin arranged in contact therewith which is arranged to increase thermal transfer between said portion of the heat pipe and the water. 
     
     
         7 . A heat exchanger according to  claim 1 , wherein the portion of each of the heat pipes within the first heat exchanging chamber comprises a fin. 
     
     
         8 . A heat exchanger according to  claim 6 , wherein the or each fin is arranged to extend in a substantially helical path around the portion of the at least one or each heat pipe within the second heat exchanging chamber. 
     
     
         9 . A heat exchanger according to  claim 1  wherein the portion of at least one of the heat pipes within the second heat exchanging chamber comprises a fin arranged in contact therewith, which is arranged to increase thermal transfer between said portion of heat pipe and the gas. 
     
     
         10 . A heat exchanger according to  claim 1 , wherein the portion of each of the heat pipes within the second heat exchanging chamber comprises a fin arranged in contact therewith which is arranged to increase thermal transfer between said portion of the heat pipe and the gas. 
     
     
         11 . A heat exchanger according to  claim 9 , wherein the or each fin is arranged to extend in a substantially helical path around the portion of the at least one or each heat pipe within the second heat exchanging chamber. 
     
     
         12 . A heat exchanger according to  claim 8 , wherein the number of turns of the or each fin per unit length around the or each heat pipe in the first heat exchanging chamber is greater than number of turns of the or each fin per unit length around the or each heat pipe in the second heat exchanging chamber. 
     
     
         13 . A heat exchanger according to  claim 1  wherein the first and second heat exchanging chambers are separated by a separation plate. 
     
     
         14 . A heat exchanger according to  claim 13 , wherein the plurality of heat pipes are supported within the heat exchanger by the separation plate which is coupled to the heat pipes at a position intermediate opposite ends of the heat pipes. 
     
     
         15 . A heat exchanger according to  claim 1 , wherein the second heat exchanging chamber further comprises at least one baffle for directing the flow of gas over the portion of the heat pipes within the second chamber. 
     
     
         16 . A heat exchanger according to  claim 15 , wherein the at least one baffle comprises a valve to control the passage of gas direct from the inlet to the outlet of the second chamber.