WO2009004014A1

WO2009004014A1 - A dishwasher

Info

Publication number: WO2009004014A1
Application number: PCT/EP2008/058468
Authority: WO
Inventors: Songul Bayraktar; Bulent Kucukcoskun; Ebru Cetinkaya
Original assignee: Arcelik Anonim Sirketi
Priority date: 2007-07-02
Filing date: 2008-07-02
Publication date: 2009-01-08
Also published as: EP2175766A1; PL2175766T3; ATE483392T1; DE602008002949D1; EP2175766B1

Abstract

The present invention relates to a dishwasher (1) wherein the deviation created in the turbidity sensor (5) measurement caused by the turbulence generated due to the water direction and intake speed into the washing chamber (2) or the motion of the spray arms (4, 104) during the washing steps is maintained to be constant and thereby the program and program parameter selections can be made with a high precision.

Description

A DISHWASHER

[0001] The present invention relates to dishwashers comprising a turbidity sensor.

[0002] In a dishwasher, a washing program is implemented that is comprised of various steps such as pre-washing, main washing and rinsing. In these machines, particularly in the machines that select the washing program to be used, turbidity sensors are used for detecting the dirt of the dishes placed in the machine or whether the dishes are properly cleaned after washing. However, these turbidity sensors used are affected by factors such as intake of water into the washing chamber and the rotational speed of the spray arms and as a result the measurement cannot be performed accurately.

[0003] Various methods are used in the technique for measuring turbidity with a high precision.

[0004] One of these methods is explained in state of the art Chinese Patent

Application No CN1682641. In this method, after water is taken into the machine before starting washing, an initial turbidity measurement is made and the pre-wash is performed according to this measurement. Afterwards, a large number of measurements are made during pre-wash and other program steps whereby the average of these is calculated and the duration of program steps and the other parameters are determined by taking into consideration the initial dirt measurement and the said average value.

[0005] In another implementation known in the technique, the Japanese Patent Application No JP2006081629, the explanation is given for a dishwasher wherein a certain time period passes for the water to settle down after water intake process ends, and afterwards turbidity measurement is made.

[0006] Another implementation known in the technique is explained in the

European Patent Application No EP1238623. In the dishwasher explained in this application, several calibration value measurements at each program step at respective times are made for the calibration of the turbidity sensor and the measured values are revised according to the calibration measurement for determining the real turbidity value.

[0007] The aim of the present invention is the realization of a dishwasher wherein the program and program parameter selection based on turbidity detection is made with high accuracy.

[0008] The dishwasher realized in order to attain the aim of the present invention is explicated in the attached claims.

[0009] In the dishwasher of the present invention, a turbidity sensor is used for measuring the turbidity of water in order to detect the dirt amount of the dishes for determining the washing program steps and the parameters such as water temperature, duration etc. relating to these steps. The turbidity sensor performs all the measurement activities while the working conditions of the spray arms are at a constant value predetermined by the producer. Thus, the deviation in the measurement of the turbidity sensor created by the turbulence due to the water intake into the washing chamber and the movement of the spray arms during the washing steps to be constant and thereby the program and program parameter selections can be made with a high precision.

[0010] If one of the turbidity measurements is performed while only the upper spray arm operates and the other while both spray arms operate during the washing steps, the deviation due to the motion of the spray arm will be high in one of these two measurements and low in the other. Similarly, even if the two measurements are taken while only the upper spray arm operates, and if the spray arm speed in one measurement is high and low in the other, the deviations manifested will be different. With the present invention, this problem is averted by performing the turbidity measurement while the speed of the pump motor and/or to which spray arm water will be directed is at a value predetermined by the producer (e.g. when only the upper spray arm is rotating with the speed w).

[0011] In an embodiment of the present invention, the turbidity sensor takes measurements only while the upper spray arm is rotating. Accordingly, measurement is taken while water is sprayed into the washing chamber with a lower pressure thereby minimizing the deviation in the measurement. [0012] In another embodiment of the present invention, the turbidity measurements are taken while both of the spray arms are rotating. Thus, measurements are made with identical deviations without disrupting the normal working process by taking the measurement in a frequent condition of the dishwasher during washing.

[0013] In an embodiment of the present invention, the turbidity is measured while the speed of the pump motor actuating the spray arms is at value predetermined by the producer.

[0014] In an embodiment of the present invention, the speed of the pump motor predetermined by the producer for taking measurements is not a speed at which the pump motor operates normally during the program steps of the dishwasher. For example, while the pump motor is operated at 2500-3000 rpm speed, the speed of the pump motor is reduced to 1500 rpm and measurement is performed when the turbulence that will cause deviation in the sprayed water is lower.

[0015] The dishwasher realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

[0016] Figure 1 - is the schematic view of a dishwasher.

[0017] The elements illustrated in the figures are numbered as follows:

1. Dishwasher

2. Washing chamber

3. Pump motor

4. 104. Spray arm

5. Turbidity sensor

[0018] The dishwasher (1) provides cleaning of the dishes in accordance with a washing program that includes at least some of the various steps like pre-washing, main washing, rinsing, drying, regeneration.

[0019] The dishwasher (1) comprises a washing chamber (2) wherein the dishes to be washed are emplaced, at least one spray arm (4, 104) that sprays water on the dishes while rotating around its axis, at least one pump motor (3) for the water to be circulated and to be sprayed from the spray arms (4, 104), at least one turbidity sensor (5) that performs the wash water turbidity measurements in order to detect the dirtiness of the dishes while the speed (w) of the pump motor (3) is only at a constant value predetermined by the producer and/or while water is directed to always the same spray arm/spray arms (4, 104) (Figure 1).

[0020] In the preferred embodiment of the present invention, two spray arms (4, 104), an upper (4) one and a lower (104) one, are used.

[0021] In an embodiment of the present invention, the turbidity sensor (5) takes measurements only while the upper spray arm (4) is rotating.

[0022] In another embodiment of the present invention, the turbidity sensor (5) takes measurements while both of the spray arms (4, 104) are rotating.

[0023] In the preferred embodiment of the present invention, a variable speed, brushless direct current pump motor (3) is used. In this embodiment, the turbidity sensor (5) takes measurements while the speed (w) of the pump motor (3) is at a value (w_m) predetermined by the producer.

[0024] In an embodiment of the present invention, the speed (w_m) of the pump motor (3) predetermined by the producer for taking measurements is a speed not normally used by the pump motor (3) during the program steps of the dishwasher (1). For example, while the pump motor (3) rotates with 2500-3000 rpm speed for pumping water in order to perform the washing processes, the turbulence of the water is high. In order to have a lower deviation in the measurement, the speed of the pump motor (3) is reduced to 1500 rpm and turbidity measurement is performed at this speed.

[0025] By means of the present invention, the deviation in the measurement of the turbidity sensor (5) caused by the turbulence generated due to the speed and direction of water intake into the washing chamber (2) or the motion of the spray arms (4, 104) during the washing steps is maintained to be constant thereby increasing the accuracy in selections of program and program parameters performed in accordance with the data received from the turbidity sensor (5).

Claims

1. A dishwasher (1 ) that comprises a washing chamber (2) wherein the dishes to be washed are emplaced, at least one spray arm (4, 104) that sprays water on the dishes while rotating around its axis, at least one pump motor (3) for the water to be circulated and to be sprayed from the spray arms (4, 104), at least one turbidity sensor (5) that measures the turbidity of the water in order to detect the dirtiness of the dishes and characterized by a turbidity sensor (5) that performs the wash water turbidity measurements while the speed (w) of the pump motor (3) is only at a constant value predetermined by the producer and/or while water is directed to always the same spray arm/spray arms (4, 104).

2. A dishwasher (1) as in Claim 1 , characterized by two spray arms (4, 104), an upper (4) one and a lower (104) one, wherein the turbidity sensor (5) takes measurements only while the upper spray arm (4) is rotating.

3. A dishwasher (1) as in Claim 1 , characterized by two spray arms (4, 104), an upper (4) one and a lower (104) one, wherein the turbidity sensor (5) takes measurements only while both of the spray arms (4, 104) are rotating.

4. A dishwasher (1) as in any one of the above claims, comprising a variable speed pump motor (3) and characterized in that the turbidity sensor (5) takes measurements only after the speed (w) of the pump motor (3) is changed to a value (w_m) predetermined by the producer.