GB611958A - Improvements in dish washing machines - Google Patents

Abstract

611,958. Dish-washing machines. WELLS, S. G. BURT-. May 14, 1946, No. 14563. [Class 138 (i)] In a dish-washing machine having a coinpartment to hold the dishes, into which hot water from a heated tank is projected from spray nozzles and from an electric motor-operated water impeller operating in a sump, and in which is provided a water inlet valve controlling the volume of hot water admitted and a drain valve to evacuate the used water, a fluidcontrolled mechanism connected with a pressure pump operated by the driving motor of the impeller maintains the pressure water supply control mechanism in operative relation while the motor is operating and automatically effects the shutting-off of the water supply if the motor drive ceases to function. Water heated in a supply tank by a thermostaticallycontrolled heater is supplied to the sprays through a pipe 21, inlet valve 20 and pipe 26, the valve 20 being self-closing. The motor drives through a gear-box the impeller in the sump and also a slow shaft 12 carrying a cam disc having cam plates 36, 37, which periodically open the valve 20 by means of a lever 32, link 33, bell-crank lever 27 pivoted at 28, and valve stem 25. A self-closing drain valve is also provided to empty the container, and is opened periodically by the rotation of a shaft 44 actuated by a lever 46 and cam plates 49, 50 on a second cam -disc on the shaft 12. The drain valve is normally held closed by a spring 51. A starter switch is arranged in the power supply lead to the water heater, thermostat and electric motor and in this circuit is arranged a micro switch D which is normally maintained closed by a spring arm 52 engaging a disc 53 on the shaft 12. On closing the starter switch the motor starts and cuts in the switch D. The cam plates 36, 37, 49, 50 are arranged so that the inlet valve is opened for a washing operation, whereafter the drain valve is opened, the inlet valve being opened a second time for rinsing, followed by a second draining. At the end of the 'cycle a notch 54 in the disc 53 engages the spring arm 52 to open the switch D and stop the motor. The motor also drives a pump which delivers oil from the gearbox through a pipe 7 to the bottom of a cylinder 8 having a loaded piston 10 and an outlet port 9 communicating with the gear-box. The piston is raised by the oil pressure and maintained at the level of the port 9. The piston has a stem 31 fixed to one end of the lever 32, which is'thereby held in a position such that the cam plates 36, 37 can actuate the valve 20. If the motor drive fails, the piston 10 drops and lowers the lever 32, whereby the inlet. valve is closed in order to avoid flooding of the container, and while the pump is inoperative the valve cannot be opened.