Hot water dispenser faucet with thermal barrier

Abstract

A faucet for a hot water dispenser has a valve metal body made of a metal having a thermal conductivity of 50 W/mK. A tube extends through a passage in the valve body and is coupled to a hot water line that extends into a hot water tank of the hot water dispenser and to a discharge outlet coupled to a discharge line that extends through a discharge spout. There is an air gap between a surface of the valve body surrounding the passage and the tube. The tube in conjunction with the air gap reduces heat transfer from the hot water flowing through the tube to the valve body. In an aspect, the tube is a plastic tube. In a variation, there is no air gap between the plastic tube and the valve body.

What is claimed is: 
     
         1 . A faucet for a hot water dispenser, comprising:
 a metal valve body having a passage therein, the metal of the metal valve body having a thermal conductivity of 50 W/mK or more;   a tube that extends through the passage in the valve body, the tube coupled to a hot water line that extends into a hot water tank of the hot water dispenser and to a discharge outlet that is coupled to a discharge line that extends through a discharge spout of the faucet; and   an air gap between an outer surface of the tube and a surface of the valve body surrounding the passage and the tube.   
     
     
         2 . The faucet of  claim 1  wherein the tube is a plastic tube, the plastic tube in conjunction with the air gap reducing heat transfer from the hot water flowing through plastic tube to the valve body wherein the plastic tube acts as a primary thermal barrier to reduce heat transfer from the hot water flowing through the plastic tube into the valve body and minimize any temperature drop in the hot water as it passes through the valve body and the air gap provides a secondary thermal barrier to further reduce heat transfer from the hot water flowing through the plastic tube into the valve body. 
     
     
         3 . The faucet of  claim 2  wherein the metal valve body is a brass valve body. 
     
     
         4 . The faucet of  claim 2  wherein the plastic tube is made from a plastic having a thermal conductivity of 0.26 W/mK or less. 
     
     
         5 . The faucet of  claim 2  wherein the inside diameter of the passage is about  8  mm and the gap is illustratively about 2 mm. 
     
     
         6 . The faucet of  claim 2  including at least one O-ring disposed around a top end of the plastic tube between the plastic tube and the valve body. 
     
     
         7 . The faucet of  claim 1  wherein the inside diameter of the passage is about 8 mm and the gap is illustratively about 2 mm. 
     
     
         8 . The faucet of  claim 1  wherein the tube is a brass tube. 
     
     
         9 . The faucet of  claim 1  wherein the valve body is a brass valve body. 
     
     
         10 . A faucet for a hot water dispenser, comprising:
 a metal valve body having a passage therein, the metal of the metal valve body having a thermal conductivity of 50 W/mK or more; and   a plastic tube that extends through the passage in the valve body, the tube coupled to a hot water line that extends into a hot water tank of the hot water dispenser and to a discharge outlet that is coupled to a discharge line that extends through a discharge spout of the faucet.   
     
     
         11 . The faucet of  claim 10  wherein the plastic tube is made from a plastic having a thermal conductivity of 0.26 W/mK or less. 
     
     
         12 . The faucet of  claim 11  wherein the metal valve body is a brass valve body. 
     
     
         13 . The faucet of  claim 10  wherein the metal valve body is a brass valve body.