GB548569A - Improvements in or relating to pasteurisation processes and plant - Google Patents

Abstract

548,569. Valves. CROSBY, W. E., MATHEWS, J., and ALUMINIUM PLANT & VESSEL CO., Ltd. May 28, 1941, No. 6835. [Class 135] [Also in Group VI] In the pasteurization of milk &c., particularly by a " short-time " process, in which a flow diversion valve operates at a predetermined temperature to divert underheated milk back to the milk tank or pipe line, means is provided for preventing the resetting of the valve so that it can be left ready for re-operation until after the lapse of a predetermined time delay. The valve may be operated automatically or a warning device may be actuated to indicate that the valve may be reset. As shown in Fig. 2, the valve 8 is raised by a weighted lever 12 on retraction of the plunger 13 of a relay solenoid 14 controlled by a heat-sensitive bulb 7 in the inlet end of a holding section e of a heat-exchanger to divert unheated milk from the cooling sections to an outlet 10 leading back to the pump or the milk tank. The bulb 7 is connected with the Bourdon tube 15 of a temperature recorder 16, the pen arm 17 of which is connected by a link 18 with a bell-crank lever 19 adapted to bridge contacts 20 to close the circuit of a relay solenoid 25 which has a plunger 30 having a contact 27 adapted to bridge contacts 28 to close the circuit of the solenoid 14. The plunger 30 is associated with a dashpot 35 for delaying the opening of the circuit of the solenoid 14 for a predetermined time after the opening of the contacts 20. In a modification, Fig. 3 (not shown) the plunger 13 is connected by a lever with a second spring- loaded plunger adapted, on the fall of the lever 12, to engage an opening therein and lock the lever while the plunger 13 is retracted. A second sensitive bulb may be located at or near the outlet end of the holding section, the arrangement being such that the valve cannot be reset until milk at the desired temperature has passed both bulbs.