Pressure control valve for refrigeration cycle

[0038] In the expansion valve 100 for a refrigeration cycle of the first embodiment configured in this way, the valve closing force of the valve body 31 is designed to be obtained by the inside pressure inside the sealed space 91 and the adjustment spring 36, while the valve opening force of the valve body 31 is obtained by the refrigerant pressure at the outlet side of the internal heat exchanger 8. The expansion valve 100 is opened and closed by the balance of the two.

[0039] On the other hand, the feeler bulb 92 is fixed abutting against the piping 81 at the outlet side of the gas cooler 2 by a band 82. The sealed refrigerant inside the feeler bulb 92 is heated by the piping temperature (that is, the refrigerant temperature of the gas cooler outlet) and that temperature is detected. Further, the outer circumference of the feeler bulb 92 and the outside wall 35 surrounding the sealed space 91 at the top of the diaphragm 32 are covered by the heat insulating packing 98, 94. The inside

[0049]FIG. 3 shows a second embodiment. The present embodiment is a so-called box type expansion valve. In the box type, instead of a feeler bulb, high pressure refrigerant is introduced below the diaphragm to detect the refrigerant temperature. More specifically, the body 33 has a first opening 33d to which a temperature sensing part having substantially half of the same function as the feeler bulb of the first embodiment is attached. This temperature sensing part is mainly comprised of a diaphragm 32, a lid 35, and a lower support member 34 and is formed inside it with a sealed space 91. That is, the lid 35 is formed at its center part with a recess 35a for forming the sealed space 91. The diaphragm 32 is fastened at its rim by being clamped between the lid 35 and the lower support member 34, whereby a temperature sensing part is formed. The diaphragm 32 is a thin film comprised of a stainless steel material and deforms and displaces in accordance with the difference in pressure insi

[0057]FIG. 5 shows a third embodiment. The third embodiment is a box type detecting the refrigerant temperature at the valve inlet. When combining this type with the cycle of FIG. 1, the refrigerant temperature after the internal heat exchanger is detected for control, while when combining this with the cycle of FIG. 4, the refrigerant temperature of the gas cooler outlet is detected for control. The actions and effects are similar to those of the second embodiment.