GB1482008A - Coffee brewing apparatus using liquid level float controller switches - Google Patents

Abstract

1482008 Water heating apparatus BUNN-O-MATIC CORP 17 Oct 1974 45135/74 Heading F4A [Also in Division H1] In a coffee brewing apparatus, a hot water tank 11, Fig. 1, is heated by an electric immersion heater 14 and hot water is fed through a siphon tube 18 into the brewing funnel 22 of the apparatus. Above the hot water tank 11 is a chamber 26 which is supplied with cold water through an inlet 29 under the control of a solenoid-operated valve 30 (Fig. 2), closure of the valve 30 being effected by a first float switch 50 when the cold water reaches a predetermined level 48, and a second back-up float switch 65 being provided for closing the valve 30 should the level of the water in the basin 26 reach a higher level 97. In the circuit diagram shown in Fig. 2, when the main switch 60 is closed and a start button 62 is depressed the brewing cycle is commenced the solenoid 31 is energized to open the valve 30, and a solenoidoperated relay 56. closes contacts 55, providing a holding circuit for the winding 57 of the relay 56 and the solenoid 31 through the normally closed contacts 54 and 64 of the float switches 50 and 65 respectively. The valve 30 remains open until the cold water in the basin 26 reaches the level indicated at 48 whereupon the float switch 50 opens contacts 54 and the solenoid 31 is de-energized to close the valve 30. The winding 57 of the relay 56 is de-energized and the contacts 55 are opened. Float switch construction.-The float switches 65 and 50 illustrated in Fig. 3 are each provided with a cylindrical float 67 carrying permanent magnets 70 which effect separation of normally closed contact reeds 71 when the float 67 is moved upwardly to a predetermined position The switch 50 is slidable in a grommet 81 to adjust the water level 48.