Water heating apparatus, especially for pools

Abstract

A water heater for heating water includes a burner assembly ( 54 ) for generating a flow of hot gas. The burner assembly ( 54 ) includes a gas burner ( 52 ) and means ( 64 ) adjustable to determine a heat output of the burner assembly ( 54 ). The water heater further includes a heat exchanger assembly ( 20 ) for transferring heat from gas to water flowing therein. The heat exchanger assembly ( 20 ) has a higher temperature zone ( 110 ) and a lower temperature zone ( 100 ). The water heater is arranged to convey the flow of hot gas to the higher temperature zone ( 110 ) and in turn to the lower temperature zone ( 100 ). The water heater further includes ducting ( 22, 23 ) to conduct said flowing water to and from said heat exchanger assembly ( 20 ), means ( 40 ) to monitor the temperature of the hot gas intermediate the higher temperature zone ( 110 ) and the lower temperature zone ( 100 ), and control means ( 70 ) responsive to the temperature monitoring means ( 40 ) to modulate the heat output of the burner assembly ( 54 ) whereby to maintain the monitored temperature within a predetermined range so as to substantially prevent or minimise condensation of vapour from the hot gas in the higher temperature zone ( 110 ). There is also disclosed a modular heat exchanger apparatus ( 20 ) including like headers ( 34 ) for redirecting fluid within respective modules ( 24 ) and for interconnecting modules ( 24 ). There is also disclosed a water heater having a condensate duct ( 84 ) to direct condensate into the water for chemically treating the water.

1 . A water heater for heating water, including:
 a burner assembly for generating a flow of hot gas, which burner assembly includes a gas burner and means adjustable to determine a heat output of the burner assembly;   a heat exchanger assembly for transferring heat from gas to water flowing therein, wherein the heat exchanger assembly has a higher temperature zone and a lower temperature zone, the water heater being arranged to convey the flow of hot gas to the higher temperature zone and in turn to the lower temperature zone;   ducting to conduct said flowing water to and from said heat exchanger assembly;   means to monitor the temperature of the hot gas intermediate the higher temperature zone and the lower temperature zone; and   control means responsive to said temperature monitoring means to modulate the heat output of the burner assembly whereby to maintain the monitored temperature within a predetermined range so as to substantially prevent or minimise condensation of vapour from the hot gas in the higher temperature zone.   
   
   
       2 . A water heater according to  claim 1  wherein use the monitored temperature is maintained within a pre-determined range without reducing the volume of water flowing through the heat exchanger. 
   
   
       3 . A water heater according to  claim 1  wherein said control means is operable to minimize said monitored temperature. 
   
   
       4 . A water heater according to  claim 1  wherein said means to monitor the temperature of the hot gas is mounted closer to the lower temperature zone than to the higher temperature zone. 
   
   
       5 . A water heater according to  claim 1  wherein the lower temperature zone and the higher temperature zone each have tubes for carrying water through the flow of hot gas, the tubes of the lower temperature zone and the higher temperature zone being formed of materials that respectively suit lower temperature operation and higher temperature operation. 
   
   
       6 . A water heater according to  claim 5  wherein the tubes of the lower temperature zone are formed of aluminium sheathed stainless steel and the tubes of the higher temperature zone are formed of cupronickel. 
   
   
       7 . A water heater according to  claim 5  wherein the tubes of the higher temperature zone are formed of copper. 
   
   
       8 . A water heater according to  claim 1  configured for the flow of hot gas to travel downwardly from the burner assembly through the higher temperature zone and in turn through the lower temperature zone. 
   
   
       9 . A water heater according to  claim 1  having means to collect condensate produced from condensation of gas in said lower temperature zone. 
   
   
       10 . A water heater according to  claim 9  including a condensate duct arranged to direct said condensate into the water for chemically treating the water. 
   
   
       11 . A water heater according to  claim 10  wherein the condensate duct is arranged to direct said condensate into the ducting from the heat exchanger assembly. 
   
   
       12 . A water heater according to  claim 10  wherein the condensate duct is arranged to direct condensate into the water upstream of a pump arranged to drive water through the water heater. 
   
   
       13 . A water heater according to  claim 10  including a venturi to draw said condensate into the water. 
   
   
       14 . A water heater according to  claim 10  including a suction tee to draw the condensate into the water. 
   
   
       15 . A water heater according to  claim 10  including a pump arranged to receive condensate from said means to collect condensate and drive said condensate through said condensate duct. 
   
   
       16 . A water heater according to  claim 9  including a dosing apparatus for storing and selectively directing metered amounts of condensate into the water at any suitable location. 
   
   
       17 . A heat exchanger apparatus, including:
 a heat exchange module having a plurality of heat exchange elements extending across a passage, the passage being arranged to convey a first fluid past and about the heat exchanger elements; and   one or more return headers adapted to be selectively mounted to said module either for directing a second fluid in turn through any adjacent pair of heat exchange elements, or for directing a second fluid from one heat exchange element of said module to a heat exchange element of a similar module when said module is coupled to said similar module.   
   
   
       18 . A heat exchanger apparatus according to  claim 17  wherein each heat exchange element is a bank of tubes. 
   
   
       19 . A heat exchanger apparatus according to  claim 18  wherein the return header has a separate sealing engagement with each tube. 
   
   
       20 . A heat exchanger apparatus according to  claim 18  wherein the banks of tubes are relatively displaced along said passage. 
   
   
       21 . A heat exchanger apparatus according to  claim 18  wherein the banks of tubes respectively form one or more lower temperature banks of tubes and one or more higher temperature banks of tubes having their tubes formed in differing materials that respectively suit lower temperature operation and higher temperature operation. 
   
   
       22 . A heat exchanger apparatus according to  claim 21  wherein the tubes of the one or more lower temperature banks of tubes are formed of aluminium sheathed stainless steel and the tubes of the one or more higher temperature banks of tubes are formed of cupronickel. 
   
   
       23 . A heat exchanger apparatus according to  claim 21  wherein the tubes of the one or more higher temperature banks of tubes are formed of copper. 
   
   
       24 . A heat exchanger apparatus according to  claim 18  having a plurality of the modules in coupled relation and a plurality of like return headers interconnecting banks of tubes within the modules and interconnecting modules. 
   
   
       25 . A heat exchanger apparatus according to  claim 18  to wherein each module has only two banks of tubes. 
   
   
       26 . A heat exchanger apparatus according to  claim 25  having two of said modules and three of said return headers, two of the return headers being respectively mounted for directing the second fluid between the banks of tubes within a respective module, and a third return header for directing the second fluid from a second bank of one module to a first bank of the other module. 
   
   
       27 . A heat exchanger apparatus according to  claim 26  wherein the successive spacings of the banks of tubes along said passage are substantially equal, and the tubes one of the modules and the tubes of the other of the module being formed in materials that respectively suit a lower temperature operation and higher temperature operation. 
   
   
       28 . A heat exchanger apparatus according to  claim 18  wherein the first fluid is hot gas from a burner assembly and the second fluid is water. 
   
   
       29 . A water heater according to  claim 1  wherein the heat exchanger assembly includes:
 a heat exchange module having banks of tubes extending across a passage, the passage being arranged to convey the hot gas past and about the bank of tubes; and   one or more return headers adapted to be selectively mounted to said module either for directing the water in turn through any adjacent pair of tube banks, or for directing the water from one bank of tubes of said module to a bank of tubes of a similar module when said module is coupled to said similar module.   
   
   
       30 . A water heater for heating water, including:
 a burner assembly for generating a flow of hot gas;   a heat exchanger assembly arranged to receive said flow of hot gas for transferring heat from the gas to water flowing therein;   ducting to conduct said water to and from said heat exchanger assembly;   means to collect condensate produced from condensation of said gas in said heat exchanger assembly; and   a condensate duct to direct said condensate into said water for chemically treating said water.   
   
   
       31 . A water heater according to  claim 30  wherein the condensate duct is arranged to direct said condensate into the ducting from the heat exchanger assembly. 
   
   
       32 . A water heater according to  claim 30  wherein the condensate duct is arranged to direct condensate into the flowing water upstream of a pump arranged to drive water through said water heater. 
   
   
       33 . A water heater according to  claim 30  including a venturi to draw said condensate into said water. 
   
   
       34 . A water heater according to  claim 30  including a suction tee to draw said condensate into said water. 
   
   
       35 . A water heater according to  claim 30  including a pump arranged to receive condensate from said means to collect condensate and drive said condensate through said condensate duct. 
   
   
       36 . A water heater according to  claim 30  including a dosing apparatus along said condensate duct for storing and selectively directing metered amounts of condensate into the water at any suitable location. 
   
   
       37 . A method of chemically treating water in a pool comprising adding to the water condensate collected from a heat exchanger assembly of a water heater through which the pool water is circulated and heated. 
   
   
       38 . A water heater according to  claim 2  wherein said control means is operable to minimize said monitored temperature. 
   
   
       39 . A water heater according to  claim 38  wherein the lower temperature zone and the higher temperature zone each have tubes for carrying water through the flow of hot gas, the tubes of the lower temperature zone and the higher temperature zone being formed of materials that respectively suit lower temperature operation and higher temperature operation.