Thermal Expansion Valve with Power Element

Abstract

An improved power element for use with a thermal expansion valve. The power element contains a filter positioned at an open end of the power element to prevent debris from entering the body of the thermal expansion valve.

We claim: 
     
         1 . A thermal expansion valve for use in an automotive air conditioner comprising:
 a body including an inlet port fluidly connected to an evaporator and an outlet port fluidly connected to a condenser;   a power element having an annular domed upper housing, a mating annular lower housing having an opening in the bottom of the annular lower housing, an annular diaphragm having an upper surface and a lower surface wherein the lower surface of the diaphragm and the annular lower housing define a diaphragm chamber, a sleeve that passes through the opening in the bottom of the annular lower housing and a stem slidably disposed within the sleeve; and   a paper filter disposed in a fluid path between the evaporator and the diaphragm chamber.   
     
     
         2 . The thermal expansion valve of  claim 1  further including a frictional clip interdisposed around the valve stem for securing the filter. 
     
     
         3 . The thermal expansion valve of  claim 1  wherein the filter is made of LyTherm® paper. 
     
     
         4 . A power element for use with a thermal expansion valve of an automotive air conditioner comprising:
 an annular domed upper housing;   a mating annular lower housing having an opening in the bottom of the annular lower housing;   an annular diaphragm having an upper surface and a lower surface wherein the lower surface of the diaphragm and the annular lower housing define a diaphragm chamber;   a sleeve that passes through the opening in the bottom of the annular lower housing;   a stem slidably disposed within the sleeve; and   a paper filter interdisposed around the valve stem.   
     
     
         5 . The power element of  claim 4  further including a frictional clip interdisposed around the valve stem for securing the filter. 
     
     
         6 . The power element of  claim 4  wherein the filter is made of LyTherm® paper.