Method for pumping a fluid out of an aquiferous household device

Abstract

In a method for pumping a fluid out of an aquiferous household device such as a dishwashing machine, a drain pump and a circulation pump are operated at least partially simultaneously to ensure that, in the event of an abrupt stop of the circulation pump, reverse flow that may cause filter cake formed by separating soiling and particles to loosen resulting in their re-soiling of the items to be cleaned. The speed of the circulation pump is lowered from a maximum speed to at least a minimum speed substantially without pressure surges before startup of the drain pump.

Claims

1. A method for pumping fluid out of an aquiferous household device having a circulation pump, a drain pump, and a control unit, said method comprising: activating the circulation pump at a first of operational speed in a first operation and lowering the speed of the circulation pump over time to a second operational speed, substantially without pressure surges, starting the drain pump and deactivating the circulation pump once the circulation pump reaches the second operational speed, deactivating the drain pump after operating the drain pump for a first predetermined period that drains a first quantity of the fluid, reactivating the circulation pump, deactivating the circulation pump after operating for a second predetermined period, and reactivating the drain pump at the conclusion of the second predetermined period to drain a second quantity of the fluid.

2. The method of claim 1, wherein the aquiferous household device is a household dishwashing machine.

3. The method of claim 1, wherein the speed of the circulation pump is reduced linearly from the first operational speed to the second operational speed.

4. The method of claim 1 wherein the speed of the circulation pump is reduced from the first operational speed to the second operational speed essentially during a period of 3 to 30 seconds.

5. The method of claim 1, wherein the first quantity is in a range between 0.5 and 3 liters.

6. The method of claim 5, wherein the first quantity is in a range between 1 and 2 liters.

7. The method of claim 1, wherein the circulation pump is operated at least temporarily at a third operational speed between the first operational speed and the second operational speed.

8. The method of claim 7, wherein the circulation pump is operated at a third operational speed during operation of the aquiferous household device in a lower basket wash cycle.

9. The method of claim 7, wherein the second predetermined period between 5 and 60 seconds.

10. The method of claim 9, wherein the second predetermined period is between 10 and 30 seconds.

11. The method of claim 7, wherein the speed of the circulation pump is linearly reduced from the third operational speed to the second operational speed during the second predetermined period.

12. The method of claim 1, wherein the speed of the circulation pump is reduced during the second predetermined period from the first operational speed to the second operational speed during a period of 3 to 30 seconds.

13. The method of claim 12, wherein the speed of the circulation pump is reduced during the second predetermined period from the first operational seed to the second operational speed during a period of 8 to 12 seconds.

14. The method of claim 11, wherein the speed is reduced from the third operational speed to 0 during the second predetermined period.

15. The method of claim 1, wherein the second quantity of fluid is equal to or less than the first quantity of the fluid.

16. The method of claim 1, wherein the first operational speed is essentially in the range between 2000 and 3000 revolutions per minute.

17. The method of claim 16, wherein the first operational speed is essentially in the range between 2300 and 2700 revolutions per minute.

18. The method of claim 1, wherein the second operational speed is essentially in the range between 1200 and 1800 revolutions per minute.

19. The method of claim 18, wherein the second operational speed is essentially in the range between 1300 and 1700 revolutions per minute.

20. The method of claim 7, wherein the third operational speed is essentially in the range between 1500 and 2000 revolutions per minute.

21. The method of claim 20, wherein the third operational speed is essentially in the range between 1700 and 2300 revolutions per minute.

22. The method of claim 1, wherein the drain pump and the circulation pump are controlled using power electronics of the control unit.

23. An aquiferous household device comprising: a circulation pump adapted to circulate fluid in the aquiferous household device; a drain pump adapted to convey the fluid out of the aquiferous household device; and a control unit configured to perform a pumping-out operation to pump the fluid out of the household device by activating the circulation pump at a first operational speed in a first operation and lowering the speed of the circulation pump over time to a second operational speed, substantially without pressure surges, starting the drain pump and deactivating the circulation pump once the circulation pump reaches the second operational speed, deactivating the drain pump after operating the drain pump for a first predetermined period that drains a first quantity of the fluid, reactivating the circulation pump, deactivating the circulation pump after operating for a second predetermined period, and reactivating the drain pump at the conclusion of the second predetermined period to drain a second quantity of the fluid.

24. The device of claim 23, wherein the aquiferous household device is a household dishwashing machine.

25. The device of claim 23, wherein the control unit is configured to linearly reduce the speed of the circulation pump from the first operational speed to the second operational speed.

26. The device of claim 23, wherein the speed of the circulation pump is adapted to be reduced from the first operational speed to the second operational speed essentially during a period of 3 to 30 seconds.

27. The device of claim 26, wherein the speed of the circulation pump can be reduced from the first operational speed to the second operational speed essentially during a period in the range of 10 to 15 seconds.

28. The device of claim 23, wherein the first quantity is in a range between 0.5 and 3 liters.

29. The device of claim 23, wherein the first quantity is in a range between 1 and 2 liters.

30. The device of claim 23, wherein the circulation pump is operated at least temporarily at a third operational speed between the first operational speed and the second operational speed.

31. The device of claim 30, wherein the circulation pump is operated at the third operational-speed during operation of the aquiferous household device in a lower basket wash cycle.

32. The device of claim 30, wherein the second predetermined period is between 5 and 60 seconds.

33. The device of claim 31, wherein the second predetermined period is between 10 and 30 seconds.

34. The device of claim 30, wherein the control unit is configured to linearly reduce the speed of the circulation pump, during the second predetermined period from the third operational speed to the second operational speed.

35. The device of claim 30, wherein the control unit is configured to reduce the speed of the circulation pump during the second predetermined period from the third operational speed to the second operational speed during a period of 3 to 30 seconds.

36. The device of claim 30, wherein the control unit is configured to reduce the speed of the circulation pump during the second predetermined period from the third operational speed to the second operational speed during a period of 8 to 12 seconds.

37. The device of claim 34, wherein the control unit is configured to reduce the speed during the second predetermined period from the third operational speed to 0.

38. The device of claim 23, wherein the second quantity of the fluid is equal to or less than the first quantity of the fluid.

39. The device of claim 23, wherein the circulation pump is operated with a maximum speed essentially in the range between 2000 and 3000 revolutions per minute.

40. The device of claim 39, wherein the circulation pump is operated with a maximum speed essentially in the range between 2300 and 2700 revolutions per minute.

41. The device of claim 23, wherein the circulation pump is operated with a minimum speed essentially in the range between 1200 and 1800 revolutions per minute.

42. The device of claim 30, wherein the circulation pump is operated, during the second predetermined period, with an average speed essentially in the range between 1500 and 2000 revolutions per minute.

43. The device of claim 30, wherein the circulation pump is operated, during the second predetermined period, with an average speed essentially in the range between 1700 and 2300 revolutions per minute.

44. The device of claim 23, wherein the control unit includes a power electronics configured to control the drain pump and the circulation pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained below with reference to a drawing, in which;

(2) FIG. 1 shows a schematic representation of an aquiferous household device,

(3) FIG. 2 shows a schematic representation of an exemplary embodiment of an inventive method for pumping a fluid out of an aquiferous household device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(4) Reference is first made to FIG. 1.

(5) An aquiferous household device embodied in the present exemplary embodiment as a household dishwashing machine GS comprises an interior IR serving as a washing container, it being possible to open and close said interior by means of a door (not shown) which is pivotably attached to the household dishwashing machine GS for loading and unloading purposes. Crockery baskets GK for receiving items to be cleaned are provided in the interior IR of the household dishwashing machine GS, with said items to be cleaned being removable from the interior IR of the household dishwashing machine GS in order to facilitate loading and unloading.

(6) In order to clean the item to be cleaned which is stored in the crockery basket GK, spray facilities embodied as spray arms SA for applying fluid to the item to be cleaned are provided in the interior IR of the household dishwashing machine GS, with it being possible for the fluid to be water applied with detergent or rinse-aid for instance, in order thus to effect a cleaning effect and/or streak-free drying of the item to be cleaned. The fluid dripping from the item to be cleaned collects in a pump sump PS, which is arranged in the base region of the interior IR of the dishwashing machine GS. A filter facility (not shown) is also provided in the pump sump PS, with which soiling or particles can be separated out of the circulating fluid.

(7) The spray arms SA are connected to a circulation pump UP in a fluid-conducting fashion by way of a supply line ZL, said circulation pump UP being arranged adjacent to other components of the household dishwashing machine GS in a base assembly BO below the interior IR of the household dishwashing machine GS. During operation, i.e. with a continuous circulation pump UP, the circulation pump UP takes in the fluid collecting in the pump sump PS and conveys it through the supply line ZL to the spray arms SA. To heat up the fluid circulated by operation of the circulation pump UP, the circulation pump UP in the present exemplary embodiment comprises an integrated water heating system WZ for heating up the fluid. Alternatively, a separate boiler or another water heating system may be provided for heating up the fluid. A drain pump LP is provided in order to empty the interior IR of the dishwashing machine GS, said drain pump LP likewise being connected in a fluid-conducting fashion to the pump sump PS and possibly being connected to a waste disposal line EL in a domestic waste disposal network.

(8) The household dishwashing machine GS also comprises control means embodied as a control electronics system SE, which is embodied by means of line means (not shown) for controlling the circulation pump and the drain pump LP. To this end, the control electronics system SE can be embodied so as to control drive motors of the circulation pump UP and the drain pump LP which are embodied as BLDC motors. Corresponding power electronics (not shown) can be provided for each of the pumps or only one power electronics unit for both pumps, so that the one power electronics unit can be used to alternately control the drain pump LP or the circulation pump UP.

(9) Reference is now made to FIG. 1 and FIG. 2 together.

(10) At the start of the pumping process, the speed of the circulation pump UP is reduced from a maximum speed nMax linearly during a first step I starting from time t0 to time t1 to a minimum speed nMin. In a step II, the speed is then reduced from nMin to zero, i.e. the circulation pump is stopped. This prevents a filter cake on the filter facility from loosening and floating, since the back-flowing quantity of fluid is no longer able to reach a level which approaches the filter facility.

(11) A first pumping process AP1 then takes place, which extends from the time t1 to the time t2 and during which a quantity of 0.5 to 3 liters is pumped out for instance. Only the drain pump LP is operated during the first pumping phase AP1, while the circulation pump UP is deactivated and therefore has the speed 0.

(12) After termination of the first pumping phase AP1, the drain pump LP is then deactivated, and the circulation pump UP is reactivated again. It is to this end operated with an average speed nUk. The household dishwashing machine GS is simultaneously operated in a lower crockery basket wash cycle, whereby only the lower spray arm SA of the two spray arms SA is operated.

(13) Subsequently, in a step III for cleaning the filter, the speed of the circulation pump UP is then reduced linearly from the average speed nUk to the minimum speed nMin. In a further step IV, the speed at time t3 is then reduced from the minimum speed nMin to 0, i.e. the circulation pump UP is stopped.

(14) A second pumping phase AP2 then takes place, which extends from time t3 to time t4, and during which a residual quantity of water is conveyed out of the household dishwashing machine GS by operation of the drain pump LP alone, with this second quantity of fluid being less than the first quantity of fluid, which was conveyed out of the aquiferous household device GS during the first pumping phase AP1.

(15) The household dishwashing machine GS is then ready to be filled again.

LIST OF REFERENCE CHARACTERS

(16) BO Base assembly EL Waste disposal line GK Crockery basket GS Household dishwashing machine IR Interior LP Drain pump PS Pump sump SA Spray arm t0 Time t1 Time t2 Time t3 Time t4 Time UP Circulation pump ZL Supply line AP1 First pumping phase AP2 Second pumping phase nMax Maximum speed nMin Minimum speed nUk Average speed SE Control electronics system WZ Water heating system