Thermal expansion valve and system including such device and method for making such device

A thermal expansion valve comprising:

• a metal tube for flowing a fluid therethrough interior walls of said tube being in contact with the fluid flowing therethrough;
• a metal rod fixed only at a first end in said tube and disposed wholly within said tube, only outer surfaces of said metal rod being in contact with the fluid flowing through said tube, said metal tube having a greater coefficient of expansion than said metal rod;
• and
• a plug having an orifice therethrough disposed in said tube proximate a free end of said rod;
• whereby
• lengthwise thermal expansion and contraction of said tube and said rod caused by temperature of the fluid in said tube and around said rod cause said free end of said rod to retreat from said plug to increase flow of the fluid therethrough, and cause said free end of said rod to approach said plug to restrict flow of the fluid therethrough, respectively;
• another tube adjacent said metal tube for carrying a fluid, the temperature of the fluid in said other tube affecting a change in the temperature of the fluid in said metal tube, whereby the expansion and contraction of said metal tube and said metal rod is affected by the temperature of the fluid in said other tube.

A thermal expansion valve system comprising:

• a first tube extending from a body for flow of a vapor/liquid fluid from said body;
• a metal second tube extending from said body for flow of liquid toward said body, a portion of said second tube being disposed within said first tube;
• a metal rod fixed in said second tube and having a free end in said second tube;
• a plug having an orifice therethrough disposed in said second tube and proximate said free end of said rod;
• said metal second tube and said metal rod having different coefficients of expansion;
• wherein an increase in vapor concentration of the fluid from said body in said first tube is operative to decrease cooling of said second tube, and the liquid in said second tube, and said rod, causing expansion of said second tube and said rod, said second tube expanding at a greater rate than said rod, to cause relative movement of said plug away from said rod free end to permit increased flow of the liquid toward said body through said plug orifice where the liquid flashes into vapor which enters said body and increases pressure in said body and increases liquid concentration of the fluid flowing from said body into said first tube.

A thermal expansion valve assembly for a refrigeration assembly, the system comprising:

• a first tube extending from an evaporator for flow of a vapor/liquid fluid from said evaporator;
• a metal second tube extending from said evaporator for flow of liquid refrigerant toward said evaporator, a portion of said second tube being disposed within said first tube;
• a metal rod fixed in said second tube and having a free end in said second tube;
• a plug having an orifice therethrough disposed in said second tube and proximate said free end of said rod;
• said metal second tube and said metal rod having different coefficients of expansion;
• wherein an increase in vapor concentration of the vapor/liquid fluid from said evaporator in said first tube is operative to decrease cooling of said second tube, and the liquid refrigerant in said second tube, and said rod, causing expansion of said second tube and said rod, said second tube expanding at a greater rate than said rod, to cause relative movement of said plug away from said rod free end to permit increased flow of the liquid refrigerant toward said evaporator through said plug orifice where the liquid flashes into vapor which enters said evaporator and increases pressure in said evaporator and increases liquid concentration of the fluid flowing from said evaporator into said first tube.