GB540779A - Improvements in or relating to mixing valves - Google Patents

Abstract

540,779. Mixing valves. HARROGATE, MAYOR, ALDERMEN & BURGESSES OF THE BOROUGH OF, and STIMSON, A. J. J. C. June 20, 1940, No. 10606. [Class 135] A thermostatically-controlled mixing valve has a ported tubular piston valve member directly actuated by a thermal bellows, fluid pressure on the bellows being balanced by the pressure on a second bellows. The valve member 1 has two series of ports 6 adapted to co-operate with corresponding ports 7 in a liner screwed into the casing at 8 with a flange 9 engaging a partition 10 separating hot and cold water inlet chambers 3, 4. These chambers are in communication with inlet fittings provided with strainers 14 and non- return valves 15. The thermal chamber comprises a rigid part having external fins 20 secured at its lower end to a bellows 23 directly engaging the closed upper end of the tubular valve member. The thermal chamber is located in an outlet fitting by longitudinal rods 21 screwed into the upper face of the main casing and is adiusted axially by a spindle screwed into the outlet fitting. Part of the outflowing mixture is discharged directly onto the bellows through ports 24 while the whole discharge passes between the external fins to the outlet which may be fitted with a thermometer. The pressure balancing bellows is secured to the casing and to a rigid thimble held against the lower end of the valve member by a spring 31 bearing against an adjustable abutment 32. According to the Provisional Specification a loading spring bears on the top of the bellows casing and is adjusted by a spindle screwed into a top cover plate. A second spring secured to an axial bearing carried by the valve member and a washer adapted to co-operate with the lower end of the valve member is adjusted by a spindle fitted with an external thread passing through the valve member into screwed engagement with the axial bearing.