Water supply apparatus

Abstract

A water supply apparatus is configured to meet energy-saving demands by controlling a pump so that the rotational speed of the pump is lowered while keeping a constant flow rate. The water supply apparatus includes a pump for pressurizing and delivering water, a frequency converter for supplying electric power to the pump to operate the pump at a variable rotational speed, a discharge-side pressure sensor for detecting a pressure at a discharge side of the pump, and a controller ( 15 ) for controlling the rotational speed of the pump. The controller ( 15 ) stores a plurality of control head curves (B, C 1 , C 2 , C 3 ) representing different relationships between flow rates (Q) and heads (H), and controls the rotational speed of the pump based on an alternatively selected one of the control head curves (B, C 1 , C 2 , C 3 ).

1 . A water supply apparatus comprising:
 a pump configured to pressurize and deliver water;   a frequency converter configured to supply electric power to the pump to operate the pump at a desired rotational speed;   a discharge-side pressure sensor configured to detect a pressure at a discharge side of the pump; and   a controller configured to control the rotational speed of the pump;   wherein the controller stores a plurality of control head curves representing different relationships between flow rates and heads, and controls the rotational speed of the pump based on an alternatively selected one of the control head curves.   
     
     
         2 . A water supply apparatus according to  claim 1 , further comprising:
 an operation panel having a selector button configured to successively switch the plural control head curves stored in the controller and an energy-saving indicator configured to indicate energy-saving levels corresponding to the control head curves used to control the rotational speed of the pump.   
     
     
         3 . A water supply apparatus according to  claim 1 , wherein the plural control head curves include a standard control head curve and a small-flow-rate-range energy-saving control head curve whose head is lower than that of the standard control head curve in a small flow rate range. 
     
     
         4 . A water supply apparatus according to  claim 1 , wherein the plural control head curves include a standard control head curve and a medium-flow-rate-range energy-saving control head curve whose head is lower than that of the standard control head curve in a medium flow rate range. 
     
     
         5 . A water supply apparatus according to  claim 1 , wherein the plural control head curves include a standard control head curve and a large-flow-rate-range energy-saving control head curve whose head is lower than that of the standard control head curve in a large flow rate range. 
     
     
         6 . A water supply apparatus according to  claim 1 , wherein the plural control head curves include a standard control head curve and a full-flow-rate-range energy-saving control head curve which extends substantially parallel to the standard control head curve and whose head is lower than that of the standard control head curve in a full flow rate range. 
     
     
         7 . A water supply apparatus according to  claim 2 , wherein the plural control head curves include a standard control head curve and a small-flow-rate-range energy-saving control head curve whose head is lower than that of the standard control head curve in a small flow rate range. 
     
     
         8 . A water supply apparatus according to  claim 2 , wherein the plural control head curves include a standard control head curve and a medium-flow-rate-range energy-saving control head curve whose head is lower than that of the standard control head curve in a medium flow rate range. 
     
     
         9 . A water supply apparatus according to  claim 2 , wherein the plural control head curves include a standard control head curve and a large-flow-rate-range energy-saving control head curve whose head is lower than that of the standard control head curve in a large flow rate range. 
     
     
         10 . A water supply apparatus according to  claim 2 , wherein the plural control head curves include a standard control head curve and a full-flow-rate-range energy-saving control head curve which extends substantially parallel to the standard control head curve and whose head is lower than that of the standard control head curve in a full flow rate range. 
     
     
         11 . A water supply apparatus according to  claim 3 , wherein the plural control head curves include a medium-flow-rate-range energy-saving control head curve whose head is lower than that of the standard control head curve in a medium flow rate range. 
     
     
         12 . A water supply apparatus according to  claim 3 , wherein the plural control head curves include a large-flow-rate-range energy-saving control head curve whose head is lower than that of the standard control head curve in a large flow rate range. 
     
     
         13 . A water supply apparatus according to  claim 3 , wherein the plural control head curves include a full-flow-rate-range energy-saving control head curve which extends substantially parallel to the standard control head curve and whose head is lower than that of the standard control head curve in a full flow rate range. 
     
     
         14 . A water supply apparatus according to  claim 4 , wherein the plural control head curves include a large-flow-rate-range energy-saving control head curve whose head is lower than that of the standard control head curve in a large flow rate range. 
     
     
         15 . A water supply apparatus according to  claim 4 , wherein the plural control head curves include a full-flow-rate-range energy-saving control head curve which extends substantially parallel to the standard control head curve and whose head is lower than that of the standard control head curve in a full flow rate range. 
     
     
         16 . A water supply apparatus according to  claim 5 , wherein the plural control head curves include a full-flow-rate-range energy-saving control head curve which extends substantially parallel to the standard control head curve and whose head is lower than that of the standard control head curve in a full flow rate range.