Fire Tube Heater

Abstract

A fire tube heater assembly, sometimes referred to as boilers and/or water heaters, and method of accommodating elongation of the fire tubes associated with such heating devices. The fire tube heater assembly includes a plurality of fire tubes that are configured and oriented to effectuate efficient thermal exchange between the heating fluid, commonly a gas combustion product, and the fluid being heated. At least one end of the plurality of tubes are supported by a tube support. The tube support includes a bellows or other deformable structure that accommodates changes in the longitudinal length associated with thermal expansion and contraction of the fire tubes during operation of the first tube heater assembly and in a manner that maintains segregation between the heating and heated fluid flows.

What is claimed is: 
     
         1 . A fire tube heater assembly comprising:
 a housing;   a plurality of tubes disposed in the housing; and   a tube support constructed to support at least two of the plurality of tubes and maintain a segregation between a combustion gas flow and a fluid disposed in the housing and effectuate thermal exchange therebetween, the tube support including a bellows section constructed to accommodate changes in the length of the at least two of the plurality of tubes caused by thermal response to operation of the fire tube heater.   
     
     
         2 . The fire tube heater assembly of  claim 1  wherein the plurality of tubes is further defined as a first group of tubes and a second group of tubes that are both supported by the tube support. 
     
     
         3 . The fire tube heater assembly of  claim 2  wherein the bellows section is disposed between the first group of tubes and the second group of tubes. 
     
     
         4 . The fire tube heater assembly of  claim 1  wherein the plurality of tubes are oriented in a concentric circular pattern. 
     
     
         5 . The fire tube heater assembly of  claim 1  wherein each of the plurality of tubes has an elongated cross-sectional shape. 
     
     
         6 . The fire tube heater assembly of  claim 1  further comprising a first inlet and a first outlet through the housing that are fluidly connected to a chamber configured to contain the fluid and a second inlet and a second outlet through the housing associated and fluidly connected to the plurality of tubes. 
     
     
         7 . The fire tube heater assembly of  claim 1  wherein the bellows section is nearer a bottom of the housing than a top of the housing. 
     
     
         8 . The fire tube heater assembly of  claim 7  further comprising a baffle configured to direct the fluid toward the plurality of tubes. 
     
     
         9 . The fire tube heater assembly of  claim 1  further comprising a divider cylinder disposed about the plurality of tubes and positionally fixed relative to the housing and configured to segregate the fluid from the combustion gas flow. 
     
     
         10 . The fire tube heater assembly of  claim 1  further comprising a burner configured to generate the combustion gas flow and fluidly connected to the plurality of tubes. 
     
     
         11 . A method of accommodating elongation of fire tube heater tubes during operation of a fire tube heater, the method comprising:
 supporting a plurality of fire tubes with a tube support structure that is deformable to concurrently accommodate changes in a longitudinal length of more than one of fire tubes.   
     
     
         12 . The method of  claim 11  wherein the tube support structure is formed as a bellows section and a first end of the bellows section is secured to a housing of fire tube heater and a second end of the bellows section is secured to each of the plurality of fire tubes and is movable relative to the first end. 
     
     
         13 . The method of  claim 12  wherein the second end of the bellows section moves away from the first end in a direction aligned with a longitudinal axis of the plurality of fire tubes as a temperature of the fire tubes increases. 
     
     
         14 . The method of  claim 12  further comprising aligning the first end and the second end of the bellows section when the fire tube heater is near an unheated condition. 
     
     
         15 . The method of  claim 11  further comprising rigidly supporting a longitudinal end of each of the plurality of fire tubes that is opposite the tube support. 
     
     
         16 . The method of  claim 11  further comprising providing a baffle to direct a flow of a fluid being heated in a radial direction toward the plurality of fire tubes. 
     
     
         17 . A boiler tube support assembly comprising:
 a body configured to sealing cooperate with an end portion of a plurality of fire tubes; and   a bellows section that extends in an outward direction aligned with a longitudinal axis of the plurality of fire tubes and which is disposed between a first portion of the body that is positionally secured relative to a housing disposed about the plurality of fire tubes and a second portion of the body that is movable relative to the first portion along the longitudinal axis in response to changes in temperature of the plurality of fire tubes.   
     
     
         18 . The boiler tube support assembly of  claim 17  wherein the first portion of the body and the second portion of the body both extend in a direction that is transverse to the longitudinal axis associated with the plurality of fire tubes. 
     
     
         19 . The boiler tube support assembly of  claim 17  wherein the bellows section is constructed to maintain separation between a heating fluid flow and a heated fluid flow. 
     
     
         20 . The boiler tube support assembly of  claim 19  further comprising at least one baffle disposed in the housing and oriented to direct the heated fluid flow in a radial direction toward the plurality of fire tubes.