Water heater for removing particulates and returning water without particulates to heater, and method of operating same

Abstract

A water heater for heating water containing particulates comprises a recirculating path responsive to water and particulates in the heater. The recirculating path removes particulates from the water flowing therein and returns water with particulates removed from it to the heater. The path includes a particulate filter for removing particulates from the water flowing in the path and a pump for pumping water in the path back into the heater. The path is responsive to a liquid cleaning agent applied to the heater with the water returned to the heater.

We claim:  
     
         1 . A water heater particularly adapted to heat water containing particulates, comprising a recirculating path arranged to be responsive to water and particulates in the heater, the recirculating path being arranged to remove particulates from the water flowing therein and to return water with particulates removed from it to the heater.  
     
     
         2 . The water heater of  claim 1  wherein the recirculating path includes a particulate filter for removing particulates from the water flowing in the path.  
     
     
         3 . The water heater of  claim 2  wherein the recirculating path includes a pump for pumping water in the path back into the heater.  
     
     
         4 . The water heater of  claim 3  wherein the pump is downstream of the filter.  
     
     
         5 . The water heater of  claim 4  wherein the recirculating path is arranged to be responsive to a liquid cleaning agent and the pump is arranged to pump the agent to the heater.  
     
     
         6 . The water heater of  claim 5  wherein the recirculating path is arranged so the liquid cleaning agent is introduced into the recirculating path between an outlet of the filter and an inlet of the pump.  
     
     
         7 . The water heater of  claim 3  wherein the recirculating path is arranged to be responsive to a liquid cleaning agent and the pump is arranged to pump the agent to the heater.  
     
     
         8 . The water heater of  claim 1  wherein the recirculating path is arranged to (a) be responsive to a liquid cleaning agent and (b) supply the cleaning agent to the heater.  
     
     
         9 . The water heater of  claim 8  wherein the recirculating path includes a pump for pumping water and the liquid cleaning agent in the path back into the heater.  
     
     
         10 . The water heater of  claim 1  wherein the water heater includes a closed tank having a vertical exterior wall arrangement and a bottom portion with a wall extending horizontally and vertically to a normally closed bottom drain, a valve arrangement coupled to the bottom drain for selectively enabling water flowing through the bottom drain to flow through it to the recirculating path, a hot water outlet connected to the tank interior, a cold water inlet having a segment in proximity to the horizontally and vertically extending wall, the cold water inlet being arranged so that in response to water being removed from the tank, cold water flows from the inlet into the bottom portion to gently wash sediment in the bottom portion toward the horizontally and vertically extending wall, the horizontally and vertically extending wall being arranged so the washed sediment drifts by gravity to the drain and the drifted sediment accumulates at and in proximity to the drain, and a controller for opening the valve from time to time for removing the washed sediment from the bottom portion via the drain and preventing accumulation of substantial sediment in the tank.  
     
     
         11 . The water heater of  claim 10  wherein the recirculating path is arranged for causing water flowing through it to flow into the cold water inlet.  
     
     
         12 . The water heater of  claim 1  wherein the cold water inlet segment comprises a generally horizontally extending manifold.  
     
     
         13 . The water heater of  claim 12  wherein the manifold includes a plurality of openings dimensioned and arranged so the cold water flows gently through them without causing turbulence in the water in the remainder of the tank.  
     
     
         14 . The water heater of  claim 13  wherein the manifold comprises a tube, the openings being only in a portion of the tube such that water flowing through the openings does not flow upwardly.  
     
     
         15 . The water heater of  claim 14  wherein the openings do not have a nozzle effect and have an area such that the flow rate of water passing through them does not cause water or sediment turbulence.  
     
     
         16 . The water heater of  claim 11  wherein the water heater includes an electric heating coil, the bottom portion wall intersecting the outer vertical wall arrangement and sloping downwardly from its intersection with the outer vertical wall toward a central axis of the tank where the drain is located.  
     
     
         17 . The water heater of  claim 11  wherein the water heater includes a gas burner and a central flue in fluid flow relation with combustion products of the gas burner, the gas burner being below the bottom portion wall, the bottom portion wall having an intersection with the flue and sloping downwardly from its intersection with the flue toward the outer vertical wall arrangement, the bottom portion wall having a sloping bottom edge having a nadir at the drain and a runway between the sloping bottom edge and the outer vertical wall arrangement; the cold water inlet segment, the bottom portion wall, the runway and the drain being arranged so that the washed sediment drifts to the bottom portion wall, thence drifts by gravity to the runway, thence drifts by gravity to the drain.  
     
     
         18 . The water heater of  claim 1  wherein the water heater includes a gas burner.  
     
     
         19 . A method of operating a water heater comprising supplying water including particulates to the water heater, heating the water in the water heater, removing some water and particulates from the water heater from time to time, from time to time removing particulates from the water removed from the water heater, and from time to time returning to the water heater the water removed from the water heater.  
     
     
         20 . The method of  claim 19  wherein the particulates are removed from time to time from the water removed from the water heater by a filter.  
     
     
         21 . The method of  claim 20  wherein the water is returned to the water heater by pumping.  
     
     
         22 . The method of  claim 21  further including supplying a liquid cleaning agent to the water returned to the water heater by pumping.  
     
     
         23 . The method of  claim 22  wherein the liquid cleaning agent and the water returned to the water heater by pumping are simultaneously supplied to the water heater.  
     
     
         24 . The method of  claim 20  further including supplying a liquid cleaning agent to the water returned to the water heater.  
     
     
         25 . The method of  claim 24  wherein the liquid cleaning agent and the water returned to the water heater are simultaneously supplied to the water heater.  
     
     
         26 . The method of  claim 19  wherein the surfaces in the water heater are cleaned by supplying a liquid cleaning agent to the water returned to the water heater.