GB745250A - Improvements in relief valve assemblages for liquid-filled cooling systems - Google Patents

Abstract

745,250. Valves. SMITH & SONS (ENGLAND), Ltd., S. July 29, 1954 [July 29, 1953], No. 20994/53. Class 135. A relief valve assembly for liquid-filled cooling systems such as those used in conjunction with internal combustion engines for motor vehicles comprises a main valve loaded so as normally to close a main vent passage but adapted to open the passage when the pressure in the system increases to a predetermined value, and an auxiliary valve capable of being set in either of two operating conditions to control an auxiliary vent passage. In the first condition, the auxiliary valve is open to vent the system unless the temperature in the system rises above a predetermined value. In the second condition the auxiliary valve is closed whatever the temperature unless the pressure in the system falls below a predetermined value. The assembly is particularly suited for use in systems where the coolant is also used for heating purposes, e.g. to heat the interior of a vehicle, for it may be arranged to give both adequate cooling of the engine and adequate heating of the vehicle under both summer and winter conditions without the use of separate summer and winter thermostats. As shown, the main valve 16 comprises two portions 17, 18 separated by a shoulder 19 forming an abutment for the loading spring 22 and also a seat for the auxiliary valve which is constituted by a sealing ring 37. The upper portion 17 of the main valve has vent apertures 21 and is loosely mounted on a boss 4. The main valve seats on a ring 14 carried by an inturned flange on a cylindrical member 11. The member 11 has a flange 12 which is swaged over a flange on a cup-shaped member 8 having vent apertures 9. The member 8 and a spring 6 are secured to the usual filler cap 1 by the boss 4 which is swaged over at 5. The flange 12 engages a sealing ring 15 carried by a filler pipe 2 having a vent 3. The sealing ring 37 is secured by a hexagonal boss 36 to a plate 35 forming the upper wall of an air-filled expansible chamber completed by a metallic bellows 34, and a cup-shaped member 33. A cup-shaped member 30 with diametrically opposite tongued spigots 31 is brazed to the member 33. The spigots 31 are slidable in cut-outs 28 in an apertured member 23 held in the valve portion 18 by annular projections 24, 25. The auxiliary valve is then closed by the loading spring 38 as shown on the left-hand side of Fig. 1. If the member 30 is then pulled down and turned through 90 degrees so that the tongues 39 of the spigots 31 engage the narrower cut-outs 29, the spring 38 is prevented from closing the auxiliary valve as shown in the righthand half of Fig. 1. In this case, which corresponds to summer conditions, the auxiliary valve is only closed upon the temperature in the system reaching the predetermined value.