GB1079721A - Improvements in or relating to thermostatically controlled mixing valves - Google Patents

Abstract

1,079,721. Valves. J. M. SHEARDOWN. Feb. 4, 1964 [Feb. 5, 1963], No. 4666/63. Heading F2V. A thermostatically controlled mixing valve for controlling the flow of two separate fluid supplies at different temperatures comprises a valve body 1, inlet means 2, 3 for each supply and outlet means 4 for fluid discharge, an apertured sleeve 7 and 8 fixed in the body 1, a plurality of sealing members 9, 10 associated with said sleeve, a spring-loaded piston 11 guided in said sleeve for axial movement therein and having valving surfaces 11<SP>1</SP> co-operating with said sealing members, thermostatic means 14 in the valve body engaging said piston and means 39 to adjust the position of the piston relative to the sleeve co-operating with the thermostatic means so that a mixture of predetermined temperature may be obtained by the adjusting means 39 and the thermostatic means 14 maintains the temperature in the event of flow variations of the separate supplies. In the drawing accompanying the Provisional Specification, cold water enters the body 1 through inlet 2, a non-return ball valve 5 on the radial apertures 18, a groove 19 on the piston, and a duct 20 to a waterway 21. Hot water passes through inlet 3, non-return ball valve 6, a groove 22 on the piston and a duct 23 to the waterway 21 where initial mixing takes place with the cold water. The mixture passes through apertures 24 into the interior of the piston and then in the direction of the arrows 25 around thermostatic means 14 which comprises an outer shell 15 joined to inner bellows 16. Some of the mixture passes between the inner bellows 16 and the piston 13 through axial grooves 26 in the piston and ducts 29 in a baffle-plate 30. The mixture then passes to the outlet 4 through apertures 32. Movement of the piston 11 over inlet aperture 18 controls the cold water supply whilst the same movement by cooperation with an 0-ring seal 9 controls the hot water supply. The initial position of the piston 11 is controlled by piston 13 which is preset by a screw 39 and adjusted by a hand knob 17. Variations from this set temperature cause expansions of the bellows and changes of the positions of piston 11 causing variations in the inlet supplies. If the piston 11 moves so that the hot water supply is completely closed and still continues moving to the left (as shown), the ram effect of the piston will close valve 6. To move the piston again under these conditions, a relief valve 44 connects to the interior of the piston 11. The relief valve also includes a bleeding device in the form of a ring of elastic material yieldably closing outside apertures in the valve body cover to come into use when the cold water inlet is open but the discharge is low. In Fig. 3, the relief valve has been dispensed with and a partition wall 61 has been incorporated so that the hot water inlet is not in direct contact with the region containing the spring 12. An aperture 62 is formed in the wall 63 to provide pressure balancing.