| 摘要 |
<p>993,692. Dishwashing machines. TAPPAN CO. April 29, 1964 [Oct. 3, 1963], No. 17792/64. Heading A4F. [Also in Divisions B2 and F2] A reversing spray arm assembly for use in a dish-washing machine comprises a reaction type spray arm adapted to receive liquid under pressure, said arm having liquid discharge orifices, means for mounting said arm freely for rotation, means for supplying liquid under pressure to said arm, and means for reversing the direction of rotation of said arm in response to a drop in liquid pressure within the arm. Upper and lower spray arms 70, 72 are mounted in washing chamber 14 containing dish racks 24, 26, the dishwasher 10 also including a depressed sump 30 with a filter cover 32, a circulating pump 54, a drain pump 60, a heating element 62 and connecting piping so that it may operate in a conventional manner. Cleaning fluid passes from pump 54 up through discharge outlet 76 and hose 78 to the plastics two part spray tubes 70, 72 which are rotatably mounted on mounting knobs 138 and 118, then out through the discharge orifices to spray the dishes to be cleaned. One end of the spray arm housing 150 (Fig. 4) is provided with radially spaced series of drive discharge orifices 170 and 172 which communicate with two separate chambers formed by partitions 174 and 180 whilst the other end has formed in it, spaced vertically disposed non-drive discharge orifices 200. Depending through which of the drive discharge orifice series 170 or 172 the fluid passes the spray arm housing 150 will be rotated in a clockwise or an anticlockwise direction. The fluid pumped into the spray arm is put into communication with one or the other chamber communicating with one of the series of drive discharge orifices by a valve assembly 192 which also blocks off communication of the fluid from the other series of drive discharge orifices to enable the housing 150 to rotate. The valve assembly 192 is so constructed that the rotation of the spray arm biases it to close the port through which fluid is communicating with the drive discharge orifices in use and open the port communicating with the other drive discharge orifices so as to reverse the direction of rotation. The fluid pressure on the valve assembly however prevents it from doing this so that this change of rotation can only occur after a drop in fluid pressure usually due to the completion of part of the dishwashing cycle. Other embodiments of spray arms and valve change over mechanisms (see Divisions B2 and F2) are disclosed, including spray arms having drive discharge orifices on both branches of the arms and dual valve mechanisms to actuate the fluid reversals for them.</p> |
