Expansion valve

An expansion valve comprising:

• a valve body having,
• a first passage through which a high-pressure refrigerant travels, and
• a second passage through which a low-pressure refrigerant travels,
• a valve positioned inside said valve body for controlling the flow of the refrigerant traveling through said first passage,
• a power element mounted to the upper end of said valve body,
• a biasing means positioned in the lower portion of said valve body for biasing said valve, and
• an aluminum heat sensing drive shaft mounted between said power element and said valve,
• power element comprises,
• an upper pressure chamber,
• a lower pressure chamber, and
• a stainless steel diaphragm mounted in the interior of the power element dividing the upper pressure chamber and the lower pressure chamber;
• the drive shaft comprises,
• a stainless steel stopper portion formed on the upper end thereof for contacting to said diaphragm;
• and
• a heat sensing shaft connected to a lower end of the stopper and removable therefrom.

An expansion valve comprising:

• a valve body,
• a power element seated at the top of the valve body having,
• a body for housing a diaphragm,
• the diaphragm made of stainless steel located in the interior of the power element forming a sealing wall separating an upper pressure chamber and a lower pressure chamber,
• said power element forming a head of the valve and filled with a heat sensing refrigerant,
• an aluminum heat sensing drive shaft extending from the diaphragm through a lower end of the body of the power element into the valve body,
• a valve, at the end of the heat sensing drive shaft opposite the diaphragm, driven in correspondence to the displacement of said diaphragm by the heat sensing drive shaft for changing a flow path area of an orifice through which a refrigerant to be sent to an evaporator travels,
• the heat sensing drive shaft comprises:
• an upper end portion, and
• a heat conducting shaft,
• said upper end portion comprising a stainless steel stopper portion and an aluminum large radius portion integrally formed on the top of the heat conducting shaft, one surface of each said portion being formed so as to contact one surface of the other said portion, and the other surface of said stopper portion being connected to a lower surface of said diaphragm and the other surface of said large radius portion being integrally formed on said heat conducting shaft;
• and
• said large radius portion is formed to be removable from said power element.