Patent GB-636749-A (GB)
Title: Improvements in or relating to dish-washing or like machines
IPC: A47L15/44
Filed: 1947-05-27
Abstract: 636,749. Dish-washing machines. HOBART MANUFACTURING CO. May 27, 1947, No. 14051. Convention date, Feb. 21. [Class 138 (i)] In a washing machine a Venturi is connected in the rinse supply line to rinse arms, a capillary tube which has means for maintaining it full of liquid being connected between the throat of the Venturi and a source of disinfectant, the capillary tube having a predetermined diameter and length to provide a substantially proportionate flow of disinfectant therethrough for uniform injection into the rinse fluid during its flow through the Venturi. As shown in Fig. 1, the machine has a semi-cylindrical movable cover 22 over the washing compartment which contains a track 21 on which a dish rack is positioned, the dishes being sprayed by an arm 27 which is fed with washing fluid by a centrifugal pump 24 which circulates the liquid from a sump 23. After washing, the dishes are rinsed by nozzles 28 positioned above and below the dishes, the nozzles being fed from an external source ; the rinsing water drains into the sump 23 which has an overflow pipe to limit the liquid level. A control valve 32 in the rinse water supply line is operated by a handle 35 which also operates a switch to control a motor 25 which drives the pump 24. The handle 35 has three positions, in one the motor 25 is switched off and the valve 32 is open, in another position the motor 25 is switched on and the valve 32 is closed and in the third position the motor 25 is off and the valve 32 closed. Disinfectant liquid from a container 111 is introduced into the rinse supply line whenever the rinse water is flowing by means of a Venturi-type injector 41, Fig. 2, which is connected to a valve chamber 43 by a nipple 65. This valve chamber has a stepped horizontal bore 70 extending centrally and which joins both the nipple 65 and a vertical bore 71, the upper end of which is closed by a plug 72. Two further horizontal bores are provided, one of which 73 joins bore 71 and the other of which communicates with both bores 71 and nipple 65. Bore 70 has an adjustable member 76 threaded into it, leakage being prevented by a sealing ring 80. The member 76 has a bore 81 with an enlarged end 82 which contains a spring 84 for pressing a ball 83 against a seat 85, the ball acting as a check valve to the bore 70 and the nipple 65. An adjustable needle valve 90 is threaded into the bore 74 and normally closes the passage leading to the nipple 65. A sealing ring 92 prevents leakage past the stem of the needle valve. Threaded into the bore 73 is a plug 101 to which is connected a capillary tube 100 which comes from the disinfectant container 111. A sleeve 103 and a sealing ring 104 prevent leakage past the plug 101. The liquid in the container 111 is maintained under atmospheric pressure by a tube 133 through its stopper 130 and contains a strainer 140 which is connected to the capillary tube 100 through a tube 110 and a connector 112. The supply line to the injector 41 has a water pressure regulator 162 and a strainer 160. Operation.-The dishes are first sprayed clean by operation of the pump 24, and are then rinsed by opening the valve 32. The rinsing water creates a suction on nipple 65 and the atmospheric pressure on the liquid in the container 111 forces disinfectant past the ball valve 83 at a rate of flow determined by the size of the capillary tube and the water pressure in the rinse supply line. Thus for a given size of capillary tube the amount of disinfectant added to the rinse water is substantially proportionate to the amount of rinse water. When it is desired to clean the capillary tube 100, valve 32 is closed and the needle valve 90 in the valve chamber 43 is opened. Water then flows through the nipple 65, past the ball valve 83 because of the enlarged end 82 of the bore 81, thence into the end of bore 70 and through bore 71 into the capillary tube.