EP2384377B1

EP2384377B1 - A washing machine comprising an air trap

Info

Publication number: EP2384377B1
Application number: EP09771376A
Authority: EP
Inventors: Mehmet Kaya; Gokhan Ozgurel; Emre Ozturk; Yavuz Sahin
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2008-12-31
Filing date: 2009-12-15
Publication date: 2012-11-28
Anticipated expiration: 2029-12-15
Also published as: WO2010076186A1; EP2384377A1

Description

The present invention relates to a washing machine wherein the water level measurement is made reliable.
In washing machines, the level of the water received in the machine is determined by measuring the pressure of the air compressed inside the air trap, which is connected to the tub, as the manometric height of the water, rising in the tub, increases, and by comparing this pressure with the reference pressure value of the tub when it is empty.
On the other hand, in horizontal-axis washing machines, in order that the spin-drying step can be efficiently performed, the laundry is required to be distributed to the drum wall equally in every direction. In the situation that the laundry cannot be distributed equally, the vibration in the washing machine increases at high speeds in the spin-drying step and this causes the dynamic and structural system of the machine to be damaged. Therefore, in horizontal-axis washing machines, unbalanced load detection methods are present. By means of these methods, the amount of unbalanced load, situated inside the machine in the spin-drying step of the machine, is determined and depending on the determined value, various distribution algorithms are applied for the distribution of the laundry on the drum wall if required and/or the spin-drying process is stopped.
In the state of the art, in order to minimize the usage of additional elements for unbalanced load detection, embodiments, aimed at achieving the same result by a single element instead of multiple elements used for water level detection and for unbalanced load detection, have been developed.
A state of the art embodiment is explained in the German Patent Application No DE19616635 . In this application, a system which measures the fluctuations, occurring due to the imbalance, with regard to the pressure data, is described.
In the state of the art European Patent Application No EP0967318 , a system which, by the pressure difference, measures the oscillations, that is, the imbalance, occurring in the tub, is explained. In an embodiment explained in the said application, the tube coming from the air trap and the tube coming from the vibration sensor are joined together by a T element and are connected to the pressure sensor by a single tube. In another embodiment, the tube coming from the air trap and the tube coming from the vibration sensor are connected to the pressure sensor separately. In this embodiment, a valve, which enables the tube coming from the air trap to be cut off when desired, is situated on the tube coming from the air trap.
In another state of the art document, the European Patent Application No EP0750065 , a method, which relates to the interpretation of the data, received by the pressure sensor from the air trap, to be used for unbalanced load detection, is explained Document DE-B3-10 2005 028 253 discloses a washing machine according to the preamble of claim 1.
However, in these state of the art embodiments, while the measurement of the water level and of the unbalanced load is desired to be performed by means of a single pressure sensor, it cannot be prevented that these measurements affect each other in different steps of the washing process and that the measurement efficiency decreases in at least one of the measurements.
The aim of the present invention is the realization of a washing machine wherein the measurement of the water level and of the unbalanced load amount is performed with low cost and high accuracy.
The washing machine realized in order to attain the aim of the present invention is explicated in the claims.
The washing machine comprises a main pipe which provides air to be transmitted to the pressure sensor, a three-way valve which is mounted to the inlet of the main pipe and which controls the air input to the main pipe and the air output therefrom, an air trap pipe, the inlet of which is connected to the air trap and the outlet of which is connected to the valve, and which provides the connection between the air trap and the main pipe, and a vibration pipe, the inlet of which is connected to the vibration transmitter and the outlet of which is connected to the valve and thus, which provides the connection between the vibration transmitter and the main pipe.
By means of the valve being three-way and of its placement, air transmission can be provided to the pressure sensor preferentially. Thus, by a single pressure sensor, also the pressure balancing between the pipes is possible for performing a robust detection while both the water level and the unbalanced load are detected.
In the preferred embodiment of the present invention, the washing machine comprises a counterweight which is disposed onto the tub. In this embodiment, the vibration transmitter is disposed onto the counterweight. The washing machine applies a washing algorithm which preferably comprises water intake, washing, discharge and spin-drying steps.
In the preferred embodiment of the present invention, a three-way and three-position valve is used. The valve is kept in the position which will allow air flow only from the air trap pipe to the main pipe throughout the water intake and washing steps. Thus, in the water intake and washing steps, the water level measurement is performed with high accuracy.
At the end of the washing step, the valve is brought to the position wherein it will allow air flow between the vibration pipe and the air trap pipe and will close the inlet of the main pipe; and thus, pressure balancing between the pipes is provided.
In the discharge step, the outlet of the vibration pipe is closed and thus, the air flow is allowed only between the air trap pipe and the main pipe, again. Thus, both the pressure inside the vibration transmitter is prevented from decreasing during the discharge step and the level of water inside the tub is provided to be determined accurately during the discharge step.
Finally, since the unbalanced load detection becomes important in the spin-drying step, the valve is brought to the position wherein air will flow into the main pipe only through the vibration pipe, and the unbalanced load measurement is provided to be performed accurately.
In another embodiment of the present invention, the valve has three ways and two positions. Thus, cost advantage is provided. In this embodiment, in the water intake, washing, discharge and spin-drying steps, the valve is kept in the positions which are explained in the previous embodiment. At the end of the washing step and before the discharge step, the valve is brought to the position wherein the vibration pipe outlet and the main pipe inlet will be open and the air trap pipe outlet will be closed.
In a version of this embodiment, in order that pressure equalization is provided at the end of the washing step and before the discharge step, the main pipe comprises a chamber. Thus, since the volume at the main pipe side is greater than the volume at the vibration pipe side, air flow is provided into the vibration pipe and thus, pressure balancing is possible.
In the preferred embodiment of the present invention, the vibration transmitter comprises a box. The box has a first compartment, and a second compartment which is filled with air inside and whereto the vibration pipe is connected. The vibration transmitter, furthermore, comprises a flexible barrier which separates the first compartment and the second compartment, and a weight which, by being located in the first compartment, applies pressure to the flexible barrier according to the vibration of the tub and compresses the air located in the second compartment.
In different embodiments of the present invention, the weight is produced from a solid or liquid material.
In an embodiment of the present invention, the vibration transmitter comprises a first transmitter which is disposed at the front side of the tub, a second transmitter which is disposed at the rear side of the tub, a vibration pipe valve which controls the air input and output from the first transmitter and the second transmitter to the vibration pipe, a first pipe which connects the first transmitter and the vibration pipe valve to each other, and a second pipe which connects the second transmitter and the vibration pipe valve to each other. Thus, as well as the determination of the unbalanced load amount, also the determination of the data that the unbalanced load is at the front or at the back is possible.
The model embodiments relating to the washing machine realized in order to attain the aim of the present invention are illustrated in the attached figures, where:
Figure 1 - is the front schematic view of a washing machine.
Figure 2 - is the front schematic view of another embodiment of the present invention.
Figure 3 - is the schematic view of the vibration transmitter used in an embodiment of the present invention.
Figure 4 - is the schematic view of the vibration transmitter used in another embodiment of the present invention.
Figure 5 - is the top schematic view of an embodiment of the present invention.
The elements illustrated in the figures are numbered as follows:

1. Washing machine
2. Drum
3. Tub
4. Air trap
5. Vibration transmitter
6. Pressure sensor
7. Main pipe
8. Valve
9. Air trap pipe
10. Vibration pipe
11. Chamber
12. Counterweight
13. Box
14. First compartment
15. Second compartment
16. Flexible barrier
17. Weight
18. First transmitter
19. Second transmitter
20. First pipe
21. Second pipe
22. Vibration pipe valve

The washing machine (1) comprises a drum (2) wherein the laundry is disposed, a tub (3) wherein the drum (2) moves, an air trap (4) wherein the air is compressed as the amount of water taken into the tub (3) increases, a vibration transmitter (5) which is disposed onto the tub (3) and wherein the air is compressed depending on the vibration of the tub (3), and a pressure sensor (6) which determines the amount of water inside the tub (3) by reading the pressure that is created by the air compressed in the air trap (4) and which determines the unbalanced load amount by reading the pressure that is created by the air compressed in the vibration transmitter (5).
The washing machine (1), furthermore, comprises

a main pipe (7) which provides air to be transmitted to the pressure sensor (6),
a three-way valve (8) which is mounted to the inlet of the main pipe (7) and which controls the air input to the main pipe (7) and the air output therefrom,
an air trap pipe (9), the inlet of which is connected to the air trap (4) and the outlet of which is connected to the valve (8), and which provides the connection between the air trap (4) and the main pipe (7),
a vibration pipe (10), the inlet of which is connected to the vibration transmitter (5) and the outlet of which is connected to the valve (8), and which provides the connection between the vibration transmitter (5) and the main pipe (7)

(Figure 1).
By means of the valve (8) being three-way and of its explained connections, in different washing steps, air transmission from the air trap pipe (9) and the vibration pipe (10) to the main pipe (7) and hence to the pressure sensor (6) can be controlled preferentially, and thus, during the performing of the unbalanced load detection and of the water level detection by means of a single pressure sensor (6), the two measurement processes are prevented from adversely affecting each other.
In the preferred embodiment of the present invention, the washing machine (1) comprises a counterweight (12) which is disposed onto the tub (3) in order to prevent the tub (3) from being displaced excessively, and the vibration transmitter (5) is disposed onto the said counterweight (12) (Figure 1). Thus, as well as the vibration transmitter (5) detects the vibration of the tub (3) with high accuracy, ease of assembly is provided.
The washing machine (1) of the present invention applies a washing algorithm which preferably comprises water intake, washing, discharge and spin-drying steps.
In the preferred embodiment of the present invention, the valve (8) is a three-way and three-position valve. Thus, both the water level measurement and the unbalanced load measurement are provided to be performed with high accuracy.
In this embodiment, throughout the water intake and washing steps, the valve (8) is kept in the position wherein it will close the vibration pipe (10) outlet, and will open the air trap pipe (9) outlet and the main pipe (7) inlet. Thus, the air flow is allowed only from the air trap (4) to the main pipe (7), and throughout the water intake and washing steps, the water level measurement is provided to be performed robustly.
At the end of the washing step and before the discharge step, the valve (8) is kept in the position wherein it will open the vibration pipe (10) outlet and the air trap pipe (9) outlet, and will close the main pipe (7) inlet. Thus, the pressure in each three of the main pipe (7), the air trap pipe (9) and the vibration pipe (10) is equalized with the pressure inside the tub (3). In the discharge step, the valve (8) is kept in the position wherein it will close the vibration pipe (10) outlet, and will open the air trap pipe (9) outlet and the main pipe (7) inlet. Thus, the pressure inside the vibration transmitter (5) is prevented from decreasing during the discharge step, and the level of water inside the tub (3) is provided to be measured throughout the discharge step.
During the spin-drying step, the valve (8) is kept in the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet. Thus, during the spin-drying step, the unbalanced load detection is provided to be performed with high accuracy without being affected by the pressure change occurring as a result of the vibrations in the air trap (4).
The position of the valve (8) in different washing steps in this embodiment is summarized in the following table.

Table 1

	Vibration pipe (10) outlet	Main pipe (7) inlet	Air trap pipe (9) outlet
Water intake and washing steps	Closed	Open	Open
At the end of the washing step, before the discharge step	Open	Closed	Open
Discharge step	Closed	Open	Open
Spin-drying step	Open	Open	Closed

In another embodiment of the present invention, the valve (8) has three ways and two positions. Thus, cost advantage is provided.
In this embodiment, in the water intake, washing, discharge and spin-drying steps, the valve (8) is kept in the positions which are explained in the previous embodiment with three ways and three positions. At the end of the washing step and before the discharge step, the valve (8) is brought to the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet.
The position of the valve (8) in different washing steps in this embodiment is summarized in the following table.

Table 2

	Vibration pipe (10) outlet	Main pipe (7) inlet	Air trap pipe (9) outlet
Water intake and washing steps	Closed	Open	Open
At the end of the washing step, before the	Open	Open	Closed
discharge step
Discharge step	Closed	Open	Open
Spin-drying step	Open	Open	Closed

As stated above, in this embodiment, at the end of the washing step and before the discharge step, the valve (8) is brought to the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet. Since the valve (8) has two positions, it is not possible for the valve (8) to close the main pipe (7) inlet and to open the air trap pipe (9) inlet for pressure equalization at the end of the washing step and before the discharge step. However, in this situation, since the volume at the vibration pipe (10) side will be greater than the volume at the main pipe (7) side, problems will be confronted during the air intake to the main pipe (7) and during the equalization of the pressure therein with the other portions.
In a version of this embodiment, in order that pressure equalization is provided at the end of the washing step and before the discharge step, the washing machine (1) comprises a chamber (11) located on the main pipe (7). Thus, at the end of the washing step and before the discharge step, the pressure equalization is provided to be performed since the total volume of the main pipe (7) and the chamber (11) will be close to the volume at the vibration pipe (10) side when the valve (8) is brought to the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet.
In another version of this embodiment, after the valve (8) is brought to the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet in order that the pressure equalization can be provided at the end of the washing step and before the discharge step, the valve (8) is provided to be brought to the position wherein it will close the vibration pipe (10) outlet, and will open the main pipe (7) inlet and the air trap pipe (9) outlet, and air intake to the main pipe (7) is provided. Then, the pressure equalization is completed by bringing the valve (8) to the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet again.
In the preferred version of this embodiment, the three-way valve (8) comprises a shutter each, which is disposed at the air trap pipe (9) outlet and at the vibration pipe (10) outlet, and a T connector which connects these shutters to the main pipe (7). Thus, the present embodiment is provided to be realized with low cost.
In an embodiment of the present invention, before the washing step, the valve (8) is kept in the position wherein it will open the vibration pipe (10) outlet, the air trap pipe (9) outlet and the main pipe (7) inlet. Thus, the pressure inside the pressure sensor (6) is balanced with the pressure in all pipes (7, 9, 10). In this embodiment, throughout at least a part of the water intake step, the valve (8) is kept in this position and thus, the value of the static pressure inside the pressure sensor (6) is provided to increase. Thus, the value of the static pressure inside the pressure sensor (6) is brought by being increased and the negative oscillations in the read pressure values are provided to be detected accurately.
Depending on the displacement occurring in the tub (3), the vibration transmitter (5) compresses the air located in the vibration transmitter (5). In the preferred embodiment of the present invention, the vibration transmitter (5) comprises

a box (13) having a first compartment (14), and a second compartment (15) which is filled with air inside and whereto the vibration pipe (10) is connected,
a flexible barrier (16) which separates the first compartment (14) and the second compartment (15) from each other,
a weight (17) which is located in the first compartment (14) and which, depending on the vibration of the tub (3), applies pressure to the flexible barrier (16) and which compresses the air located in the second compartment (15)

(Figure 3 and Figure 4).
The weight (17) moves together with the tub (3) and thus, makes a vibration movement on the flexible barrier (16) at the same frequency of the tub (3) vibration, which depends on the load in the drum (2).As a result of this movement, the air located in the second compartment (15) is compressed and moves towards the vibration pipe (10). Thus, in the situation wherein the valve (8) allows air flow from the vibration pipe (10) to the main pipe (7) and hence to the pressure sensor (6), the pressure change, which is created by the air compressed as a result of the vibration of the weight (17), is measured by the pressure sensor (6). Thus, the amount of the tub (3) vibration at that time, in other words, the unbalanced load amount is determined.
In an embodiment of the present invention, the weight (17) is produced from a solid material, for example, from wood or metal (Figure 3). In another embodiment of the present invention, the weight (17) is a fluid, for example, oil which fills the first compartment (14) (Figure 4).
In an embodiment of the present invention, the vibration transmitter (5) comprises

a first transmitter (18) which is disposed at the front side in order to detect the vibration at the front side of the tub (3),
a second transmitter (19) which is disposed at the rear side in order to detect the vibration at the rear side of the tub (3),
a vibration pipe valve (22) which controls the air flow from the first transmitter (18) and the second transmitter (19) to the vibration pipe (10),
a first pipe (20) which provides the connection between the first transmitter (18) and the vibration pipe valve (22), and
a second pipe (21) which provides the connection between the second transmitter (19) and the vibration pipe valve (22)

(Figure 5).
Thus, as well as the determination of the unbalanced load amount, also the determination of the data that the load is at the front or at the back is possible. In this embodiment, during the spin-drying step, while the valve (8) is in the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet, the vibration pipe valve (22) is first brought to the position wherein it will open the first pipe (20) outlet and will close the second pipe (21) outlet, and the data of the vibration at the front side of the tub (3) is received from the first transmitter (18). Then, the vibration pipe valve (22) is brought to the position wherein it will close the first pipe (20) outlet and will open the second pipe (21) outlet and thus, this time, the data of the vibration at the rear side of the tub (3) is received from the second transmitter (19). By considering the difference between these two data, it is decided that the unbalanced load is at the front or at the back.
In the washing machine (1) of the present invention, the data relating both to the unbalanced load and to the water level is provided to be measured with high accuracy by using a single pressure sensor (6).
It is to be understood that the present invention is not limited to the embodiments disclosed above and a person skilled in the art can easily introduce different embodiments. These should be considered within the scope of the protection postulated by the claims of the present invention.

Claims

A washing machine (1) comprising a drum (2) wherein the laundry is disposed, a tub (3) wherein the drum (2) moves, an air trap (4) wherein the air is compressed as the amount of water taken into the tub (3) increases, a vibration transmitter (5) which is disposed onto the tub (3) and wherein the air is compressed depending on the vibration of the tub (3), and a pressure sensor (6) which determines the amount of water inside the tub (3) by reading the pressure that is created by the air compressed in the air trap (4) and which determines the unbalanced load amount by reading the pressure that is created by the air compressed in the vibration transmitter (5), characterized by
- a main pipe (7) which provides air to be transmitted to the pressure sensor (6),

- a three-way valve (8) which is mounted to the inlet of the main pipe (7) and which controls the air input to the main pipe (7) and the air output therefrom,

- an air trap pipe (9), the inlet of which is connected to the air trap (4) and the outlet of which is connected to the valve (8), and which provides the connection between the air trap (4) and the main pipe (7),

- a vibration pipe (10), the inlet of which is connected to the vibration transmitter (5) and the outlet of which is connected to the valve (8), and which provides the connection between the vibration transmitter (5) and the main pipe (7).
A washing machine (1) as in Claim 1, characterized by a counterweight (12) which is disposed onto the tub (3) in order to prevent the tub (3) from being displaced excessively, and by the vibration transmitter (5) which is disposed onto the counterweight (12).
A washing machine (1) as in Claim 1 or 2, wherein a washing algorithm, comprising water intake, washing, discharge and spin-drying steps, is applied.
A washing machine (1) as in any one of the above Claims, characterized by the three-way and three-position valve (8).
A washing machine (1) as in Claim 4, characterized by the valve (8) which, throughout the water intake and washing steps, is kept in the position wherein it will close the vibration pipe (10) outlet, and will open the air trap pipe (9) outlet and the main pipe (7) inlet.
A washing machine (1) as in Claim 4 or 5, characterized by the valve (8) which, at the end of the washing step and before the discharge step, is brought to the position wherein it will open the vibration pipe (10) outlet and the air trap pipe (9) outlet, and will close the main pipe (7) inlet.
A washing machine (1) as in any one of the Claims 4 to 6, characterized by the valve (8) which, in the discharge step, is kept in the position wherein it will close the vibration pipe (10) outlet, and will open the air trap pipe (9) outlet and the main pipe (7) inlet.
A washing machine (1) as in any one of the Claims 4 to 7, characterized by the valve (8) which, during the spin-drying step, is kept in the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet.
A washing machine (1) as in any one of the Claims 1 to 3, characterized by the three-way and two-position valve (8).
A washing machine (1) as in Claim 9, characterized by the valve (8) which, throughout the water intake and washing steps, is kept in the position wherein it will close the vibration pipe (10) outlet, and will open the air trap pipe (9) outlet and the main pipe (7) inlet.
A washing machine (1) as in Claim 9 or 10, characterized by the valve (8) which, at the end of the washing step and before the discharge step, is brought to the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet.
A washing machine (1) as in any one of the Claims 9 to 11, characterized by the valve (8) which, in the discharge step, is kept in the position wherein it will close the vibration pipe (10) outlet, and will open the air trap pipe (9) outlet and the main pipe (7) inlet.
A washing machine (1) as in any one of the Claims 9 to 12, characterized by the valve (8) which, during the spin-drying step, is kept in the position wherein it will open the vibration pipe (10) outlet and the main pipe (7) inlet, and will close the air trap pipe (9) outlet.
A washing machine as in any one of the above Claims, characterized by the vibration transmitter (5) that comprises
- a box (13) having a first compartment (14), and a second compartment (15) which is filled with air inside and whereto the vibration pipe (10) is connected,

- a flexible barrier (16) which separates the first compartment (14) and the second compartment (15) from each other,

- a weight (17) which is located in the first compartment (14) and which, depending on the vibration of the tub (3), applies pressure to the flexible barrier (16) and which compresses the air located in the second compartment (15).
A washing machine (1) as in any one of the above Claims, characterized by the vibration transmitter (5) that comprises
- a first transmitter (18) which is disposed at the front side in order to detect the vibration at the front side of the tub (3),

- a second transmitter (19) which is disposed at the rear side in order to detect the vibration at the rear side of the tub (3),

- a vibration pipe valve (22) which controls the air flow from the first transmitter (18) and the second transmitter (19) to the vibration pipe (10),

- a first pipe (20) which provides the connection between the first transmitter (18) and the vibration pipe valve (22), and

- a second pipe (21) which provides the connection between the second transmitter (19) and the vibration pipe valve (22).