Expansion valve

An expansion valve for controlling the flow rate of a refrigerant supplied to an evaporator of a refrigerating system, comprising:

• an expansion valve housing with a high-pressure supply passage and a low-pressure return passage;
• a temperature-sensing chamber located to sense the temperature and pressure of the refrigerant returning from said evaporator, said temperature-sensing chamber containing 1) a sealed charge of at least a saturated vapor gas, and 2) a displaceable diaphragm wall having a surface within said temperature-sensing chamber;
• a valve mechanism including a valve in said supply passage, said valve mechanism being actuated by displacement of said diaphragm wall via at least one push-rod to open and to close said supply passage;
• and
• thermal-transfer-delay means, separating said temperature-sensing chamber from said return passage and provided between said return passage and said temperature-sensing chamber, for delaying the thermal transfer of a temperature change from the refrigerant in said return passage to said sealed charge within said temperature-sensing chamber, said thermal-transfer-delay means comprising a plug having a transfer path formed therein for the transfer of both temperature and pressure changes to said temperature sensing chamber.

An expansion valve for controlling the flow rate of a refrigerant supplied to an evaporator of a refrigerating system, comprising;

• an expansion valve housing with a high-pressure supply passage and a low-pressure return passage;
• a temperature-sensing chamber located to sense the temperature and pressure of the refrigerant returning from said evaporator, said temperature-sensing chamber containing 1) a sealed charge of at least a saturated vapor gas, and 2) a displaceable diaphragm wall having a surface within said temperature-sensing chamber;
• a valve mechanism including a valve in said supply passage, said valve mechanism being actuated by displacement of said diaphragm wall via at least one push-rod to open and to close said supply passage;
• and
• thermal-transfer-delay means, separating said temperature-sensing chamber from said return passage and provided between said return passage and said temperature-sensing chamber, for delaying the thermal transfer of a temperature change from the refrigerant in said return passage to said sealed charge within said temperature-sensing chamber,
• said thermal-transfer-delay means comprising an intermediary plug made of one of rubber, plastics, and a porous material with a low thermal conductivity,
• said intermediary plug being fixed to one of said seat body and said housing bore and being pierced by at least one small-sized channel or bore extending from the return passage towards the lower side of said diaphragm wall of said temperature-sensing chamber.

An expansion valve for controlling the flow rate of a refrigerant supplied to an evaporator of a refrigerating system, comprising;

• an expansion valve housing with a high-pressure supply passage and a low-pressure return passage;
• a temperature-sensing chamber located to sense the temperature and pressure of the refrigerant returning from said evaporator, said temperature-sensing chamber containing 1) a sealed charge of at least a saturated vapor gas, and 2) a displaceable diaphragm wall having a surface within said temperature-sensing chamber;
• a valve mechanism including a valve in said supply passage, said valve mechanism being actuated by displacement of said diaphragm wall via at least one push-rod to open and to close said supply passage;
• and
• thermal-transfer-delay means, separating said temperature-sensing chamber from said return passage and provided between said return passage and said temperature-sensing chamber, for delaying the thermal transfer of a temperature change from the refrigerant in said return passage to said sealed charge within said temperature-sensing chamber,
• said thermal-transfer-delay means comprising an intermediary plug made of one of rubber, plastics, and a porous material with a low thermal conductivity,
• said intermediary plug being designed with a sliding bore said push-rod extending through said sliding bore towards said lower side of said diaphragm wall, the inner diameter of said sliding bore being slightly larger than the exterior diameter of said push-rod so that a restricted flow channel is defined between the said push-rod and said intermediary plug.

An expansion valve for controlling the flow rate of a refrigerant supplied to an evaporator of a refrigerating system, comprising;

• an expansion valve housing with a high-pressure supply passage and a low-pressure return passage;
• a temperature-sensing chamber which is located on an exterior side of said housing proximate said return passage and which senses the temperature and the pressure of the refrigerant returning from said evaporator, said temperature-sensing chamber containing 1) a sealed charge of at least a saturated vapor gas, and 2) a displaceable diaphragm wall having a surface within said temperature-sensing chamber;
• a valve mechanism including a vale in said supply passage, said valve mechanism being actuated by displacement of said diaphragm wall via at least one push-rod to open and to close said supply passage;
• and
• thermal-transfer-delay means, separating said temperature-sensing chamber from said return passage and provided between said return passage and said temperature-sensing chamber, for delaying the thermal transfer of a temperature change from the refrigerant in said return passage to said sealed charge within said temperature-sensing chamber,
• said thermal-transfer-delay means comprising a plug having a transfer path formed therein for the transfer of both temperature and pressure changes to said temperature sensing chamber.

An expansion valve for controlling the flow rate of a refrigerant supplied to an evaporator of a refrigerating system, comprising:

• an expansion valve housing a with a high-pressure supply passage and a low-pressure return passage;
• a temperature-sensing chamber located to sense the temperature and pressure of the refrigerant returning from said evaporator, said temperature-sensing chamber containing a sealed charge of at least a saturated vapor gas and a displaceable diaphragm wall having an inside surface within said temperature-sensing chamber;
• a valve mechanism including a valve in said supply passage, said valve mechanism being actuated by displacement of said diaphragm wall via at least one push-rod to open and close said supply passage, and
• adsorption means, fixed to said inside surface of said diaphragm wall, for adsorbing a liquefied part of said saturated vapor gas which is condensed and liquefied on said surface and for holding said liquefied part on said surface of said diaphragm wall inside said temperature-sensing chamber;
• and
• thermal-transfer-delay means, separating said temperature-sensing chamber from said return passage and provided between said return passage and said temperature-sensing chamber, for delaying the thermal transfer of a temperature change from the refrigerant in said return passage to said sealed charge within said temperature-sensing chamber.