Gas water heater

Abstract

A domestic gas storage water heater utilizes a plastic non pressure tank to deliver mains pressure hot water. The heater may be external or internal of the tank and has a heat out put of about 4-10 Mega joules per hour. A pressure transfer module uses the mains pressure of the incoming cold water to deliver hot water from the tank at mains pressure. The tank may be of larger storage capacity than conventional gas heaters and the arrangement ensures that the heated water in the tank is stratified into layers of different temperature. This enables an uninterrupted supply of hot water to be achieved.

1 . a combustion water heater which includes 
 a) a non-pressurised water storage tank having a cold water inlet in the lower portion of said tank and a heated water outlet in the upper portion of said tank    b) a low heat output combustion chamber having a flue for the egress of combustion gases    c) a heat exchange surface associated with said flue    d) means for contacting water from the lower portion of said water storage tank with said heat exchange surface    e) means for conducting water heated at the heat exchange surface to the upper portion of said water storage tank    f) pump means associated with the heated water outlet to increase the pressure of water exiting from the non pressurised tank.    
     
     
         2 . A water heater as claimed in  claim 1  in which the water in the tank is stratified by temperature with the hottest water adjacent the hot water outlet.  
     
     
         3 . A water heater as claimed in  claim 1  wherein the heat exchange surface is disposed within the water storage tank.  
     
     
         4 . A water heater as claimed in claim one wherein the pump means is a multi compartmented pressure transfer module adapted to release hot water at near mains pressure by utilising the existing mains pressure of the cold water inlet.  
     
     
         5 . A water heater as claimed in  claim 1  wherein the heat exchange surface is disposed within the lower portion of the tank and the tank incorporates a shroud which separates the water in the lower portion of the tank, which surrounds the heat exchanger, from the water in the remainder of the tank, and a water outlet allows water from within the lower portion to rise to the upper section of the tank.  
     
     
         6 . A water heater as claimed in  claim 1  or  2  in which the energy out put of the combustion unit is 1 to 2 kilowatts.