GB1218063A - Heat exchange circuit - Google Patents

Abstract

1,218,063. Refrigerating; heating by circulation of fluids. AMERICAN AIR FILTER CO. Inc. 19 Jan., 1968 [24 Jan., 1967], No. 3046/68. Headings F4H and F4U. In a heat exchange circuit in which a fluid is circulated to be alternately vaporized and condensed, a condenser has at least two separate fluid flow paths which are controlled in accordance with either the pressure or the temperature of the fluid leaving the condenser. The condenser may have four flow paths leading to inlets 9a, 11a, 12a and 13a of a valve casing 10, as shown in Fig. 3. Fluid from the condenser flows through a casing outlet 14 to the remainder of the circuit. A piston 21 having sealing rings 22 slides in the casing between an upper position in which the inlets 9a, 11a and 12a are open and a lower position determined by a stop 20 in which those inlets are closed. The inlet 13a remains permanently open. The position taken up by the piston depends on the pressure in the chamber 27 below the piston acting against a compression spring 23. Thus if, for example, the pressure of fluid from the condenser rises, the piston will rise to open a further condenser flow path or paths and the resultant increased condenser cooling capacity will reduce the condenser outlet pressure. The chamber 28 above the piston has an outlet 16 with a relief valve 16a so that any fluid leaking past the piston from the chamber 27 maintains a constant pressure on the upper face of the piston. In a modification, Fig. 4 (not shown), the piston moves in accordance with the temperature in the chamber below the piston. That chamber includes a temperature responsive device of the type filled with expansible fluid which raises the piston with increasing temperature. The spring above the piston serves only to maintain the piston in contact with the device. The heat exchange circuit may be a compression-condensation refrigeration circuit, Fig. 1 (not shown), or may, as shown in Fig. 2, be a circuit including a heated vapour generator 41 and an air heating condenser 40. Vapour passing from the generator and the condenser drives an engine 42 which powers a fan 47 for passing air over the condenser, a pump 53 for moving fluid around the heat exchange circuit, a generator fuel pump 48, and a generator combustion air supply fan 44. The fuel supply is controlled by a valve 49 in accordance with the temperature of heated air leaving the condenser. An automatically controlled engine by-pass 45 maintains a constant pressure drop across the engine.