GB821760A - Pressure and temperature responsive regulating system for valves - Google Patents

Abstract

821,760. Refrigerating. SVENSKA TURBIN AKTIEBOLAGET LJUNGSTROM. Aug. 12, 1957 [Aug. 23, 1956], No. 25398/57. Class 29 [Also in Group XXIX] A thermostatic expansion valve comprises a movable partition 6, Fig. 1, separating a bellows-enclosed chamber 3 from a chamber 13 in which fluid pressure, after passage through a restricted orifice 14, acts on a smaller area of the partition so that, in the event of a rapid change of pressure in the chamber 3 due to variation of temperature sensed by a feeler 1 subject to evaporator temperature, the partition is initially deflected beyond the position that. it finally attains when the pressures on either side of the orifice 14 have become equalized. Instead of the orifice 14 in the partition, an internal pipe 15 with an adjustable valve 16 may be provided. The partition 6, which operates the expansion valve member 8 through rods 7, is also responsive to the pressure at the outlet of the valve transmitted through passages 11 to a chamber 10 enclosed by a bellows 9. In a modification, the rods 7 and passages 11 are outside the bellows 9 and the orifice 14 interconnects the chambers 3, 10. In a further modification, the bellows 5, 9 are interchanged so that the partition is responsive to evaporator temperature, valve outlet pressure and rate of change of valve outlet pressure. Fig. 3 illustrates a further embodiment having three bellows 5, 9, 18 associated with a fixed partition 19 and a pair of movable partitions 6, 17 whereby the apparatus is responsive to temperature, pressure, and the rate of change of both of these characteristics.