Enhanced draining and drying cycles for an automatic dishwasher

• US 5,797,409 A
• Filed: 05/09/1997
• Issued: 08/25/1998
• Est. Priority Date: 06/08/1995
• Status: Expired due to Term

• Current Assignee: Maytag Corporation (Whirlpool Corporation)
• Original Assignee: Maytag Corporation (Whirlpool Corporation)
• Inventors: Corbett, Mitchell N., Cooper, Randall L., Cracraft, Mark A.
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): Markoff, Alexander
• Application Number:
  US08/853,635
• Time in Patent Office: 473 Days
• Field of Search: 134/18, 134/25.1, 134/25.2, 134/57 D, 134/58 D, 134/56 D
• US Class Current: 134/18
• CPC Class Codes: A47L 15/0031 Water discharge phases
• CPC Class Codes: A47L 15/0034 Drying phases, including dripping-off phases
• CPC Class Codes: A47L 15/4297 Arrangements for detecting or measuring the condition of the washing water, e.g. turbidity
• CPC Class Codes: A47L 2401/023 Quantity or concentration of the consumable product
• CPC Class Codes: A47L 2401/08 Drain or recirculation pump parameters, e.g. pump rotational speed or current absorbed by the motor
• CPC Class Codes: A47L 2401/10 Water cloudiness or dirtiness, e.g. turbidity, foaming or level of bacteria
• CPC Class Codes: A47L 2401/12 Water temperature
• CPC Class Codes: A47L 2401/24 Spray arms status, e.g. detection of spray arm rotation
• CPC Class Codes: A47L 2501/01 Water supply, e.g. opening or closure of the water inlet valve
• CPC Class Codes: A47L 2501/02 Water discharge, e.g. opening or closure of discharge valve
• CPC Class Codes: A47L 2501/12 Air blowers
• CPC Class Codes: A47L 2501/30 Regulation of machine operational steps within the washing process, e.g. performing an additional rinsing phase, shortening or stopping of the drying phase, washing at decreased noise operation conditions

Abstract

An automatic dishwashing machine includes enhanced drying and draining cycles. Toward the end of the rinse and hold cycle when the water is draining, a second quantity of water is added to the machine resulting in a purging action which reduces the concentration of soil in the wash pump. During the normal wash cycle, if the dishwashing machine determines that the water is sufficiently dirty, a second drain is initiated to remove any dirty water that is present in the bottom of the pump after the first drain. During the dry cycle, the machine senses the temperature of the water and the presence of a rinse aid to select an appropriate dry cycle. The possible dry cycles include a delayed dry cycle and a pulsed dry cycle.

Claims

1. A method of controlling a wash cycle of a dishwasher having a pump and at least one rotating wash arm comprising the steps of:

(a) causing the pump to pump a washing liquid to said at least one rotating wash arm to cause the rotating wash arm to rotate with a rotational speed, whereby the pump consumes a current;

(b) monitoring the rotational speed to determine if the rotational speed has decreased;

(c) monitoring the consumed current to determine if the consumed current has decreased;

(d) draining the washing liquid from the dishwasher upon the determination that the rotational speed has decreased and the consumed current has decreased; and

(e) filling the dishwasher with water and operating the pump during at least a portion of the filling.

2. The method of claim 1 wherein water is added to the dishwasher during a last portion of the draining of the dishwasher.

3. The method of claim 2 wherein the last portion is approximately 30 seconds long.