Patent GB-687220-A (GB)
Title: Improvements in or relating to dishwashers
IPC: A47L15/42
Filed: 1950-10-04
Abstract: 687,220. Dishwashing machines. HOBART MANUFACTURING CO. Oct. 4, 1950 [Oct. 11, 1949], No. 24238/50. Class 138 (i). Also in Group I] A dishwashing machine comprises a washing chamber having a sump with a valve controlled drain outlet, a strainer assembly overlying the sump and including a downwardly extending portion enclosing and surrounding the drain outlet to collect larger food particles within the strainer immediately adjacent the outlet, and a liquid circulating pump having its inlet outwardly of the strainer to prevent recirculation of the collected food particles. The machine, Fig. 1, has an inner shell 20 enclosing the washing chamber 22, a lower casing 23 forming the sump 24 and a front door 26 hinged on a horizontal axis. An electric sequence timer controls the operation of the machine. The strainer assembly, Fig. 4, includes a generally square' perforate upper section 120 having rounded corners and seated on a complementary recessed portion 121 of the shell 23 so as to separate the chamber 22 from the sump 24. The section 120 slopes downwardly towards an opening 122 approximately coaxial with the drain outlet 80. A middle perforate annular section 124 is welded in the opening 122 and the section 124 is in turn welded to a downwardly extending frusto-conical perforate section 125 extending at its lower end' into a valve collar 77. A separate inner strainer 130 having a central portion 131 and a curved outer rim 132 is removably seated on the strainer section 124. The strainer sections 120, 124 and 125 have fine perforations of the order of 1/16 of an inch in diameter whereas the strainer 130 is provided with two series of holes 133, 134 of relatively large diameter of the.order of 5/16 of an inch. The portion 131 of the strainer 130 telescopes over an overflow tube 86 having fitted at its lower end the drain valve 85 seatable on a surface 88 of the collar 77. The valve 85 has a pair of oppositely disposed arms 90, Fig. 8, connected integrally with a sleeve 91 slidable on a vertical pin 92 fixed in the valve housing 75. The sleeve has two opposite flats 95 having rounded shoulders 97, 96 at the upper and lower ends. The other two opposite sides of the sleeve are tapered. The flats and shoulders co-operate with resilient yoke arms 105 of a lever 100 pivoted within a pair of rubber washers 102 secured in the valve housing 75. The valve 85 is normally biassed to the open position by a U-shaped spring 110, Fig. 1, secured at its ends to either side of the housing 75 and with its mid-portion engaging the lever 100. The outer end of the rod is connected through a spring 116 to a solenoid 115 which when energised through the timer causes the valve to close. A pump housing 60 for a motor driven impeller 55 is removably secured in position in the sump through the agency of a pair of wing nuts 71, Fig. 1. The housing has an inlet 61 in the sump and an outlet 62 passing through the strainer section 120. Rotatably mounted at the outlet' on a fixed stud 67 is a reaction operated wash arm 64 disposed in the bottom of the chamber 22. In operation under control of the timer water introduced into the machine at 45, Fig. 1, maintains a level at the top of the overflow tube 86 the valve 85 being closed. This water is circulated to the chamber 22.and back to the sump through the strainer assembly. Only finely entrained food particles will pass through the' strainer, all normal sized particles will pass through the perforations 133 and collect in the strainer section 125. Particles which are too' large to be flushed down the drain outlet are: collected around the separate strainer 130. This strainer will also catch any article of silverware should it fall into the sump. When the valve 85 is opened the collected' food particles in the section 125 will be flushed into the drain pipe 80 and the strainer assembly will be cleaned at the same time. To facilitate cleaning, the wash arm can be removed by lifting it off the stud 67. The strainers 130, 120-125 can then be lifted out and afterwards the overflow tube and drain valve can be removed first by twisting them through 90 degrees to release the arms 105 and then lifting the unit. The impeller 55 may then be exposed by releasing the wing nuts 71 and removing the housing 60. All these parts may be removed and reassembled through the door opening. The tapered sides of the drain valve sleeve 91 facilitate reassembling of the valve by guiding the sleeve between the yoke arms prior to a final twisting movement through 90 degrees.