Patent GB-774893-A (GB)
Title: Improvements in and relating to apparatus for washing dishes and the like
IPC: A47L15/06
Filed: 1952-10-31
Abstract: 774,893. Dishwashing machines. GENERAL ELECTRIC CO. Oct. 31, 1952 [Nov. 1, 1951], No. 27433/52. Class 138(1) [Also in Group XXIX]  A dishwashing machine 1 comprises a vat 3 Fig. 1, an impeller 17, and a drain opening 28, the impeller hub being secured on a shaft 12 extending upwardly through the opening 28, wherein the foot of the hub or a ring secured thereto has a clearance with the bottom 22 of the vat 3 and is divided with a plurality of segments constituting pump elements, the spaces between the segments forming passages 35 through which water can pass - from the vat into the hub and thence to the opening 28 when the impeller is at rest, the flow of liquid to the opening 28 being prevented by the segments, when the impeller is rotating. The vat 3, has a front opening door 4. A water inlet 7 is supplied from a pipe 10, a solenoid operated valve and pipe 9 and the impeller 17 is driven from a motor 11 and has air circulating blades 20 and liquid circulating blades 18. An electric heating element 21, preferably of the type described in Specification 144,767 [CLass 38(i)], surrounds the impeller and a sump 24 is in communication with the vat through the drain opening 28. The machine performs automatically, washing (with detergent), rinsing and drying cycles, through the agency of a timer motor (not shown), controlled from a switch 6 in known manner. The sump 24 is drainable by gravity through an outlet 25, trap 26 and pipe 27 and is provided with a guard tube 14 concentric with the motor shaft 12 and with its upper end disposed above the normal water level in the vat. The wall of the impeller hub 16 below the blades 18 is thickened and in close proximity with the vat bottom 22, which slopes gradually towards the opening 28. This thickened wall is divided into a plurality of pump elements 32, Fig. 2, so as to form the liquid passages 35. When the impeller 17 is rotating the elements 32 interrupt the liquid and direct it away from the opening 28. In the embodiment of Fig. 5, the sump 45 is partitioned at 52 to form a pump chamber 53 in which operates the blades 62 of an impeller pump. The blades are mounted on a tubular hub 55 which is secured to the motor shaft 51 which drives the liquid circulating impeller 40. Liquid can enter the pump chamber 53 from the upper portion of the sump 45 through an opening 61 in the partition 52. The sump 45 is large enough to accommodate the entire quantity of liquid used during any washing or rising operation. A ring 44 is secured to the inner wall of the impeller hub 41 and this ring is formed with pump elements, in a similar manner to the embodiment of Fig. 1, which elements control the drain openings 28 in the vat bottom 22. A tangential outlet 54 of the chamber 53 connects with a vertical pipe 64, Fig. 6, terminating in an elbow 66. The open end of the elbow 66 discharges into a funnel 77 in a cup 73 supported in a valve body 69, connected at 70 to a standard sink drain. Mounted in the valve body 69 is a float ball 78 having a stem 81 slidable in a bore 82 in a valve 80 associated with the open end of the elbow. The valve 80 is supported by a light spring 83 resting on the ball 78, the spring passing through a hole in the funnel 77 and a valve seat 75 in the cup, which latter is provided with air holes 76. A cross wire 86 limits the downward movement of the valve assembly 78-80. Should the sink drain become clogged liquid will rise in the pipe 70 and start to fill the body 69. The ball 78 then rises and through the stem and spring seats the valve 80 on the end of the elbow 66 to prevent liquid from the vat passing through the holes 76 on to the floor. As the liquid continues to rise in the body 69 the spring 83 is compressed and the ball 78 closes the seat 75 to prevent drain water falling on to the floor. The liquid being pumped up the pipe 64 to the elbow 66 is returned 'to the vat through a tube 90 passing into the vat with its end 92 covered by a shield 93 provided with apertures 94. The end 91 of the tube 90 is concentric with the pipe 64. In operation whilst the impeller 40 is rotating, liquid is prevented, by the pump elements of the ring 44, from passing through the opening 28. When the impeller stops the whole of the liquid is received in the sump 45. The impeller motor is then restarted automatically so that the pump blades 62 eject the liquid through the anti-syphon device 68 to the sink drain.