Patent GB-775064-A (GB)
Title: Apparatus for mixing liquids of different temperatures
IPC: B01F5/00
Filed: 1955-09-01
Abstract: 775,064. Mixing liquids. A'BECKETT, W. J.. Sept. 1, 1955 [Sept. 10, 1954; Feb. 21, 1955; March 24, 1955; June 6, 1955], No. 25104/55. Class 86 Apparatus for mixing liquids of different temperatures to provide a constant temperature efluent comprises a housing having inlet ports for liquids of different temperatures and an outlet port for mixed effluent, a hydraulically-actuated valve and a thermally-responsive means being disposed in the housing, the thermally-responsive means being adapted to actuate a valve which varies the pressure of liquid to which the hydraulicallyactuated valve is responsive as the temperature in the housing falls below or rises above a predetermined setting so that the hydraulically-actuated valve reduces or increases, respectively, the input of the cold liquid. As shown, a mixing chamber 1 has two inlets 3, 4 for entrance respectively of cold and hot liquid, the inlet 3 leading to a flanged tube 5 extending through an opening in which the shank of a hydraulically actuated valve is screwed. The valve comprises a pair of sleeves 10, 19 bolted together and surrounding a valve stem 11 with an enlarged head 12. Sufficient clearance exists between the head 12 and the surrounding sleeve 10 to permit liquid to pass. The sleeve 19 is provided with a spirally-wound bi-metallic strip 20 which engages one end of a control rod 27 the other end of which is adapted to actuate a ball valve 26 located at a pasageway 25 in the sleeve 10. The rod 27 may be adjusted to open and close the valve at any predetermined setting by rotation of a lever arm 29 outside the cover plate 2. The sleeve 19 is adapted to close either of two series of radial ports 14, 15 provided for supplying respectively hot and cold liquid to the mixing chamber. When the apparatus is connected to sources of hot and cold liquid supply cold liquid will flow through passage 3 tube 5 and ports 15 to the chamber and will also flow up the hollow valve stem 11 and through a fine drilling 16 to the annular space around the stem and eventually into the space 38 above the head of the valve stem. This will provide a pressure differential which will move the sleeves upwardly whereby the ports 15 are partly closed and the ports 14 are gradually opened allowing hot liquid to enter the mixing chamber. As the temperature of of the mixed liquid rises the bi-metallic strip will act to open gradually the valve 26 whereby the pressure in the space 38 is reduced and the sleeves 10, 19 move downwardly to reduce the inflow of hot liquid and increase the inflow of cold liquid. A state of equilibrium is soon reached. Conical ring 41 may be provided to direct the hot and cold entering liquids towards the bi-metallic strip. An adjustable relief valve 47 may be provided to prevent excessive pressure building up within the sleeve 10. If the cold liquid pressure should fall below that required for operation, the apparatus may still be able to operate, by the provision of a hollow rod 39 held by a light spring 40 against the tube 5, and extending into a narrowed portion of the bore of the valve stem. The cold liquid cannot flow into the mixing chamber until the pressure is sufficient to raise the rod 39 against the pressure of the spring 40.