GB779003A - Improvements relating to dishwashing machines - Google Patents

Abstract

779,003. Dishwashing machines. RUMBAUGH, H. M. March 16, 1955, No. 7705/55. Class 138(1) A dishwashing machine comprises a washing chamber 10, Fig. 1, a circular bladeless impeller drum 30 having a smooth outer surface mounted therein for rotation in either direction about an axis extending transversely of the chamber, so as to throw water over the dishes, and a container 80 for detergent, arranged so that water is prevented from entering the container when the drum rotates in one direction and water enters the container to wash out detergent, when the drum rotates in the opposite direction. As shown in Figs. 1 and 2 the washing chamber 10, having a front opening sur- 'rounded by a rubber or like seal 19, is mounted in a housing 16, the opening being closable by a door 15 hinged to the front wall 18 of the housing. The impeller 30, in the form of a smooth cylinder is mounted within a shallow sump 12 of the chamber 10, on a shaft 31 rotatable in either direction by a reversible motor 36, through the agency of a belt drive 37. An air vent slot 21 having a splash shield 22 is provided in the upper part of the chamber side walf 13, Fig. 2, and another air vent slot 26, Fig. 1 is provided in the front wall of the chamber adjacent the sump 12, a plate 27 being provided to prevent water escaping through the slot 26. A slot 25 in the wall 18 provides access of air to the slot 26. Water is supplied to the chamber 10 at 41 from an inlet connection 43, a solenoid-operated inlet valve 44 and a pipe 42. Drainage of the sump 12 is effective at 45 through a pipe 46, solenoid-operated drain valve 49, a rotary pump 40, driven by the motor 36, and a drain pipe 47. A manually-started timer 50 of known type controls the valves 44, 49 a heater element 90 and the motor 36 so that once started the machine performs pre-washing, washing (i.e. with a detergent added to the water), rinsing and drying operations, in timed sequence. A diaphragm-operated switch 39, opening into the bottom of the sump, is arranged in the circuit of the valve 44 and is actuated by the pressure of water in the sump to de-energize the solenoid of the valve 44 when the water in the sump reaches a desired level, as indicated in Fig. 3. Pivotally mounted adjacent the impeller 30, Figs. 1 and 3 is the baffled container 80 for detergent 81, the container being movable from the position shown in dotted lines, wherein it is filled with detergent, to an operative position indicated in full lines. Below the impeller and the level of the sump water is mounted a filter screen 60 which extends along the entire length of the impeller. The heating element 90 which extends along both sides of the impeller 30 and the rear end thereof, is positioned beneath the water level between the impeller and the screen, and additional perforated screen plates 61 are mounted between the screen 60 and the sump bottom. Dishes to be washed and dried are supported in racks 70 extending above and on both sides of the impeller. In operation the water level is sufficient to partially submerge the impeller 30 as shown in Fig. 3. During a pre-washing operation water clings to the impeller surface and is thrown tangentially and upwardly therefrom over the dishes as shown in Fig. 3. Owing to the nature of the baffled container 80 water will be substantially prevented from entering the container. Small particles of waste from the dishes will be prevented from recirculation by being trapped under the screen 60. Large particles of waste will be prevented from approaching the drain opening 45 by the plates 61 and may be subsequently manually removed from the sump. When the impeller is rotated in the opposite direction (see Fig. 4) during a washing operation, the water will enter the container 80 and wash out the detergent. Water immediately prior to being carried upwardly by the impeller surface passes over the respective leg of the heating element 90. Any suds which mount-up along the edges of the screen 60, are repelled by water thrown downwardly from the impeller. When water is drained from the sump the screen 60 is freed of waste particles, as water flows downwardly therethrough, these particles being carried away through the drain opening 45. After a final rinsing the dishes are dried by air drawn in through the slot 26 by the impeller and passing over the top of the element 90 and out through the vent 21. The arrangement whereby water thrown over the dishes in alternate directions is heated immediately before leaving the impeller surfaces, ensures that maximum water and air temperatures at surfaces of the dishes are obtained. Specification 779,004, is referred to. Reference has been directed by the Comptroller to Specification 712,582.