Patent GB-730992-A (GB)
Title: Improvements in and relating to dishwashing machines
IPC: A47L15/50
Filed: 1953-01-05
Abstract: 730,992. Dishwashing machines. GENERAL ELECTRIC CO. Jan. 5, 1953 [Jan. 4, 1952], No. 277/53. Class 138 (1). A dish-washing machine comprises a tub 3, a dish rack 6, 6a, means 14 for introducing liquid into the tub, means 24 for directing the liquid against the dishes, a pump 16 having an inlet pipe 18 for drawing liquid from a sump portion 21 of the tub, a discharge pipe 22 from the pump to the means 24 and a drain branch 30 opening from the inlet pipe 18 intermediate the ends thereof and extending angularly from the pipe, the capacity of the pump 16 relative to gravity flow through the inlet pipe being such that, when the pump is in operation, it will prevent liquid rising to the level of the drain branch 30 and the construction and arrangement being such that when the pump is stopped the liquid will rise to the level of the drain branch 30 and discharge therethrough, sufficient liquid being retained in the inlet pipe 18 or in the sump to prime the pump for subsequent operation. In the machine, Fig. 1, the tub 3, has a front opening door 4; the dish rack 6, 6a can be rolled over the door when open into the tub to be supported therein on rails 9; the sump 21 is covered by a screen 33 and the water inlet means 14 communicates by a pipe 12 with a solenoid operated water valve 10. A timermotor driven sequence switch 15 controls the dish-washing cycle in known manner, but the machine may be manually controlled. The sump 21 connects with the inlet pipe 18 of the pump 16 driven by a motor 17, and the discharge pipe 22 of the pump connects by a pipe 23 with the means 24 in the form of a rotary water reaction operated spray device having arms 26 provided with upper and lower spray heads 25. The device 24 is disposed between upper and lower portions 6a and 6, of the rack. The drain branch pipe 30 extends substantially at right-angles from the pipe 18 and connects with a drain trap 31 through a check-valve 32 which is optional. When the pump is operating, having already been primed from the previous operation, it discharges water through the device 24 faster than water enters the pipe 18 and hence there is no build-up of water to the level of the branch 30 and no water is lost to the drain. In two other embodiments the rotary spray device is situated below the dish rack and the pump discharge pipe passes through the screen over the sump. The first of these other embodiments discloses a pump and pump inlet pipe within an enlarged sump, the inlet pipe extending downwardly therein with its open end near the bottom of the sump and with the drain branch extending outwardly from the vertical portion of the pump inlet pipe. In a further embodiment the drain branch slopes downwardly towards the pump inlet pipe so that when the pump is operating there is an aspiration effect within the branch to positively prevent entry of water into the branch. Another embodiment discloses a drain branch sloping downwardly away from the pump inlet pipe and provided with a lip projecting into the inlet pipe so that when the pump is operating some water is bled through the drain branch. During this operation water will be introduced to the tub through the fitting 14 to make up for the loss of water through the drain branch.