EP1545283B1

EP1545283B1 - A device and method at an inlet device in a household appliance

Info

Publication number: EP1545283B1
Application number: EP03791536A
Authority: EP
Inventors: Bernt Svensson; Mats Lilja
Original assignee: Asko Cylinda AB
Current assignee: Asko Cylinda AB
Priority date: 2002-08-30
Filing date: 2003-08-29
Publication date: 2011-11-16
Anticipated expiration: 2023-08-29
Also published as: SE524065C2; DK1545283T3; SE0202577D0; ATE533394T1; SE0202577L; AU2003253563A1; EP1545283A1; WO2004019749A1

Abstract

The present invention relates to a device and a method in an inlet device in a household appliance for the detection and removal of the presence of obstacles for the function of an inlet device (6) comprising at least one inlet valve (7, 12) for the intake and closing off of water to a household appliance (2). The inlet valve (7, 12) is electrically controlled for adjustment between an open and a closed position. The device comprises a flow meter (15) arranged in series with the inlet valve (7, 12) which can detect a flow of water even when this is not supposed to occur. A control unit (16) is arranged to when the flow meter (15) detects a flow of water when this should not occur to emit a control signal which is arranged to initiate the said inlet valve (7, 12) is opened during a predetermined period of time following which said inlet valve (7, 12) is closed.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a device for detecting and removing the presence of obstacles for the function in an inlet device comprising at least one inlet valve for the inlet and closing off of water to a household appliance which uses water, with the inlet valve being electrically controllable for adjustment between an open and a closed position. The device further comprises a flow meter which is arranged in series with the inlet valve, which flow meter is arranged to detect a flow of water even during periods when this is not supposed to occur, and a control unit which, when the flow meter detects a flow of water during a period when this is not supposed to occur, is arranged to emit a control signal.
The present invention also relates to a method for said device.

TECHNICAL BACKGROUND

Many households today use some kind of household appliance which uses water, for example a dishwasher or a laundry machine. In order to supply water from the water supply to the machine, there is normally some kind of coupling from a suitable outlet point in the household to the household appliance in question. There is often some kind of manual safety valve available, by means of which the user can turn off or respectively turn on the water supply to the household appliance in question, in order to decrease the risk of leakage when the household appliance is not in use.
The household appliance as such is equipped with some kind of inlet valve which is controlled automatically by the equipment which controls the rest of the household appliance. This valve is during operation normally under pressure from the water supply via the above mentioned coupling, and is open at suitable times in order to supply water. It is suitably placed in connection to the point where the coupling from the attachment point is attached to the household appliance. These kinds of inlet valves are preferably designed so that there is an element which hermetically locks the supply of water and which, in this position, is in a spring-biased end position. This element is in turn coupled to a solenoid, which when it is provided with a suitable voltage pulls the blocking element away, towards the force of the biasing spring so that the supply of water is enabled. When a suitable amount of water then has been supplied, the voltage is removed from the solenoid, causing the spring to press the blocking element back so that the supply of water is interrupted. This kind of valve is referred to as a magnetic valve, since it is the electromagnetic force of the solenoid which controls the supply of water.
The earlier mentioned manual safety valve is to be shut when the machine is not in use, in order to decrease the risk of overflow in the case of a leakage in said magnetic valve. However, this cannot always be assured, and a manual safety valve is not always available. Thus, the household appliance will fill with water if the safety valve is not closed or is not available at the same time as the magnetic valve in some way is stopped from being closed, which can result in an overflow. Also, during normal operation, when a safety valve should be open, the magnetic valve can in some way be stopped from being closed, causing the household appliance to be filled with water even when this should not take place according to the program sequence of the household appliance which can result in an overflow.
A previously known way of counteracting this is to equip the inlet with double magnetic valves coupled in series, thereby obtaining a kind of redundancy. In US 4441521 and US 4450863 , double magnetic valves are described for the inlet of water to a dishwasher. The solenoids are supplied with voltage at the same time, thus opening both of the valves. The voltage is also removed at the same time from the solenoids, causing the two valves to close.
The above means that if one of the magnetic valves is stopped from closing there is still one which works. The probability of both magnetic valves ceasing to function at the same time is considered to be very small.
It can however occur that particles such as flakes or particles of sand can block the function of the magnetic valves even in the case of double valves. Such particles can cause the magnetic valves to almost close, due to the influence of the respective spring, but leaving a sufficient opening for a certain flow of water to be present through the magnetic valves, thus causing the risk of an overflow. If this takes place during operation, the rest of the function of the household appliance will also be affected when water is supplied, even during those periods when this is not to take place.
DE 195 48 514 A1 describes a domestic appliance, with a water supply, having a flow meter in the water feed.

SUMMARY OF THE INVENTION

A main purpose of the present invention is to supply a device and a method to detect and remove the presence of particles which disturb the function of said inlet valves in a household appliance.
This purpose is obtained by means of a device according to the invention, which device comprises a flow meter placed in series with the inlet valve, preferably downstream from the inlet valve. This flow meter is arranged to detect a flow of water even during periods when this is not supposed to occur. The device further comprises a control unit, which when the flow meter detects a flow of water during a period when this is not supposed to occur is arranged to emit a control signal. In addition, the control signal emitted by the control unit is arranged to initiate that said inlet valve is opened and shut one or several times after the undesired flow of water has been detected.
This purpose is also obtained by means of a method according to the invention, which comprises the flow measurement downstream from both inlet valves for the detection of a flow of water during periods when this is not supposed to occur. When a flow of water is detected during a period when this is not to occur, a control signal is emitted. In addition, said control signal is arranged to initiate that the supply of water is opened during a predetermined time, causing the interruption of said supply of water.
Said inlet valves are preferably constituted by magnetic valves.
In a particularly preferred embodiment, the above method is repeated a predetermined number of times, following which a control unit is arranged to either separately or in combination terminate the dishwasher program and start an outlet pump arranged in the dishwasher, and to send an error message to the user.
Said household appliance is preferably a dishwasher or a laundry machine.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will in the following be described in connection to examples of preferred embodiments and the appended drawings, in which

Fig. 1: is a view from behind of a household appliance to which the present invention is applied;
Fig. 2: is a partial cut view of a closed magnetic valve;
Fig. 3: is a partial cut view of an open magnetic valve;
Fig. 4: shows an inlet with double magnetic valves;
Fig. 5: is a partial cut view of a closed magnetic valve where a complete closure has been blocked;
Fig. 6: shows an inlet with double magnetic valves, and a flow meter arranged downstream from the magnetic valves; and
Fig. 7: is a front view of a household appliance on which the present invention is applied.

PREFERRED EMBODIMENTS

In the following, a preferred embodiment will be described. It will relate to a dishwasher for household purposes. This should however not be seen as a limitation for the invention, but only as an example of an implementation of the invention.
With reference to Fig. 1, some sort of coupling 3 is needed to supply water from the water grid 1 to a dishwasher 2, from a suitable attachment point 4 in the household to the dishwasher 2. Often, there is some sort of manual safety valve 5 in the form of a closure valve available, by means of which the user can turn off or on the supply of water to the dishwasher 2 in order to decrease the risk of leakage when the dishwasher 2 is not in use.
The dishwasher 2 is, as such, equipped with an inlet at which an inlet device 6 according to the invention is arranged, and is controlled automatically by the equipment which controls the rest of the dishwasher 2. This inlet device 6 exhibits inlet valves which, during operation, normally are under pressure from the water grid 1 via the earlier mentioned coupling 3, and are opened at suitable points in time in order to supply water. They are suitably arranged in connection to the point where the coupling 3 from the connection point 4 is attached to the dishwasher 2.
Such an inlet valve 7 is shown in Fig. 2, and preferably has the function of an element 8 blocking the supply of water from an area A in a water conduit 9 to an area B in said water conduit 9, where said areas A, B are arranged on each side of the inlet valve 7. The area B is arranged downstream from the area A, with the area B thus being positioned closer to the washing space of the dishwasher than area A. Area A and area B are in Fig. 2 separated by the element 8. In this position the element 8 is in an end position, biased by a spring 10. This element 8 is in turn coupled to a solenoid 11, which, when it is supplied with a suitable voltage U, pulls the blocking element 8 away against the force of the biasing spring 10, so that water supply is enabled from area A to area B, which is illustrated in Fig. 3. When a suitable amount of water has been supplied, the voltageu is removed from the solenoid 11, causing the spring 10 to press the blocking element 8 back so that the supply of water is interrupted, and the state in Fig. 2 is regained. This kind of inlet valve 7 is called a magnetic valve, since it is the electromagnetic force of the solenoid 11 which controls the supply of water.
The earlier mentioned and in Fig. 1 shown manual safety valve 5 should be shut when the dishwasher 2 is not in use, in order to decrease the risk of overflow in the case of leakage in said magnetic valve 7. However, this cannot be assured, and a manual safety valve 5 is not always present. Thus the dishwasher 2 will fill with water if the safety valve 5 is not closed or is not available at the same time as the magnetic valve 7 in some way ceases to function, which can result in an overflow. Also, during normal operation, when a possible safety valve 5 should be open, the magnetic valve 7 can in some way cease to function, causing the dishwasher 2 to fill with water even when this should not take place according to the program sequence of the dishwasher 2 which could result in an overflow.
Thus, as shown in Fig. 4, use is made of double magnetic valves 7, 12 for the inlet of water to a dishwasher 2. The solenoids 11, 13 are supplied with voltage at the same time, causing them to open both of the magnetic valves 7, 12. The voltageu is also removed at the same time from the solenoids 11, 13, causing the two magnetic valves 7, 12 to close. The above means that if one of the magnetic valves 7, 12 would cease to function, there is still one which functions. The probability of both magnetic valves 7, 12 ceasing to function is considerably smaller than in the case of only one valve 7 being present.
However, as shown in Fig. 5, there can occur particles 14 such as flakes from for example cracked washers or sand particles, which obstruct the function of both of the magnetic valves 7, 12. In Fig. 5, an illustration is shown of how this might look for the magnetic valve 7. Such particles as the shown particle 14 can cause the magnetic valve 7 to almost close due to the influence of the spring 10, but leaving a sufficient opening for a certain flow of water through the magnetic valve 7 from area A to area B. When there are two inlet valves present and one of them is obstructed from closing, the inlet device carries out its function and this malfunction is not detected which does not have any practical significance either. If it takes place for both of the in Fig. 4 shown magnetic valves 7, at 12 there is a risk of over flow due to water coming in, although the valves 7, 12 are intended to be closed. If this occurs during operation, the rest of the function of the dishwasher 2 will also be disturbed since water is supplied even during the periods when this is not supposed to occur.
By means of the method and the device of the invention, there is thus both detection and removal of the presence of particles such as the particle 14 shown in Fig. 5 which obstructs the function of said magnetic valves 7, 12,
For this purpose, there is comprised in a device according to the invention as shown in Fig. 6 a flow meter 15 arranged downstream from the two magnetic valves 7, 12, which can detect the presence of the flow of water even during periods when this should not occur, that is when the magnetic valves 7, 12 are supposed to be closed.
The direction of the flow of water is shown with an arrow in Fig. 6. This is detected by a control unit 16, which when the flow meter 15 detects the flow of water during a period when this should not occur, that is when the solenoids 11, 13 are not supplied with voltageu, delivers a control signal to a power unit 17 which then supplies a voltageu, to the solenoids 11, 13 comprised in the magnetic valves 7, 12. They are then opened during a predetermined period of time, following which the voltageu is removed so that said magnetic valves 7, 12 are again closed. Because of this, the particles 14 which blocked the closing of the magnetic valves 7, 12 will hopefully have been removed. The control unit 16 can be of a kind which is used to control the cleaning process in a dishwasher 2, and is in principle known as such.
If there remains a detected flow of water which the flow meter 15 detects during a period when this should not occur, the control unit 16 again delivers a voltageu from the power supply 17 to the solenoids 11, 13 comprised in the magnetic valves 7, 12. The magnetic valves 7, 12 are then opened again during a predetermined amount of time, following which the voltageu is removed so that said magnetic valves 7, 12 are again closed.
If, despite this being repeated a predetermined number of times, for example two times, the undesired flow of water remains, the control unit 16 is arranged to, either separately or in combination, terminate the dishwashing program and to start an outlet pump 18 arranged in the dishwasher 2, see Fig. 7, at the same time as an error message is sent to the user. The error message can either be in the shape of a light or a sound signal, or a text message on a display 19 arranged in the dishwasher 2, or a combination of those.
In a particularly preferred embodiment, with renewed reference to Fig. 6, the flow meter 15 consists of a blade breaker and a magnet arranged in an impeller (not shown in details), and the number of times which the breaker is opened and closed is proportional to the flow of water. This kind of flow meter 15 is generally known, and is not described in more detail. If the flow meter 15 detects a flow of water which exceeds a certain threshold value when no flow of water should occur according to the program of the cleaning sequence, the program is stopped. Probably, particles 14 have then blocked the closure of the two magnetic valves 7, 12. Following this, the magnetic valves 7, 12 are opened a period of time in the interval of 1-5 seconds, for example for about 2 seconds, following which they are closed for a period of time in the interval of 5-20 seconds, for example for approximately 12 seconds. If the flow meter 15 detects a water flow which exceeds a certain threshold during a time in the interval of the final 3-12 seconds, for example the last approximately 6 seconds of the previously mentioned 5-20 seconds, the above mentioned cycle will be repeated. If the flow meter 15 then still measures a flow of water which exceeds a certain threshold value, the program is terminated and the outlet pump 18 is started. An error signal starts to sound continuously at the same time as the display 19 shows an error message as a text. It should be noted that this sequence is only an example of how the invention can be designed, and should not be seen as a limitation of the invention; for example the above mentioned cycle can be repeated more or fewer times before an error message is given.
The invention is not limited to that which has been described above, but various embodiments are possible within the scope of the claims. Suitably, the invention can also be applied to other household appliances with an inlet of water, such as for example a washing machine. The invention can also be applied to such a household appliance with only one inlet valve for the control of the water intake. In the case that the kind of inlet valve which is used is a magnetic valve, the activation could be of such a kind that the valves are closed when voltage is supplied, and open in the absence of voltage. The used kind of inlet valve can also be of another kind than a magnetic valve, for example a motor valve which is driven between two stable end positions by activation with a voltage pulse.

Claims

An inlet device (6) for detecting and removing obstacles, comprising at least one inlet valve (7, 12) for the intake and closing off of water to a household appliance (2) which uses water, with the inlet valve(s) (7, 12) being electrically controllable for adjustment between an open and a closed position; which device (6) further comprises a flow meter (15) which is arranged in series with the inlet valve(s) (7, 12), which flow meter (15) is arranged to detect a flow of water even during periods when such is not supposed to occur, and also a control unit (16) which, when the flow meter (15) detects a flow of water during a period when this is not supposed to occur, is arranged to emit a control signal; characterized in that the control signal emitted by the control unit (16) is arranged to initiate that said inlet valve(s) (7, 12) is are opened during a predetermined period of time, following which the control unit (16) is arranged to close said inlet valve(s) (7, 12); aid flow meter (15) being placed downstream from the inlet valve(s) (7, 12).
The inlet device (6) according to of claim 1, characterized in that if the flow meter (15) still detects a flow of water during a period when this should not occur following the inlet valve(s) (7, 12) having been opened once and closed again due to the flow meter (15) having detected a flow of water during a period when this should not occur, the control unit (16) is arranged to emit a new control signal in order to again open said inlet valve(s) (7, 12) during a prearranged period of time, following which said inlet valve(s) (7, 12) is are again closed.
The inlet device (6) according to any of the previous claims, characterized in that said inlet valves (7, 12) are two and are arranged in series.
The inlet device (6) according to any of the previous claims, characterized in that said household appliance (2) is a dishwasher.
The inlet device (6) according to any of claims 1-3, characterized in that said household appliance (2) is a laundry machine.
Method for detecting and removing obstacles for the function of an inlet device (6), using at least one electrically controllable inlet valve (7, 12) for adjustment between an open and a closed position for the intake and closing off of water to a household appliance (2) which uses water; which method comprises measuring the flow through the inlet valve(s) (7, 12) for detecting a flow of water during periods when this should not occur, and when a flow of water has been detected during a period when this should not occur, that is when the inlet valve is controlled to the closed position, a control signal is emitted ; characterized in that said control signal initiates that said inlet valve(s) (7, 12) is are opened during a predetermined period of time, following which said inlet valve(s) (7, 12) is are closed.
The method according to claim 6, characterized in that said control signal is arranged to initiate either separately or in combination:
the termination of the program sequence of the household appliance (2);

an outlet pump (18) arranged in the household appliance (2) to be started;

an error signal in the form of a sound to be started;

an error message to be sent to the user via a display (19) arranged in the household appliance (2).
The method according to either of claims 6 or 7 characterized in that if a flow of water is still detected during a period when this should not occur following the inlet valve(s) (7, 12) having been open once and closed again due to the detection of a flow of water during a period when this should not occur, the inlet valve(s) (7, 12) is are opened during a predetermined period of time, following which said inlet valve(s) (7, 12) is are closed.
The method according to claim 8, characterized in that the opening and closing of the inlet valve(s) (7, 12) is repeated a number of times.
The method according to claim 6, characterized in that it further comprises:
if a water flow exceeding a certain threshold value is detected when no flow of water should occur according to the program of the cleaning sequence, the household appliance is stopped;

two serially coupled magnetic valves (7, 12) are opened during a time in the interval of 1-5 seconds following which they are closed during a period of time in the interval of 5-20 seconds;

if a flow of water exceeding said certain threshold value is detected during a time in the interval of the final 3-12 seconds of the previously mentioned interval of 5-20 seconds, the above mentioned cycle is repeated;

the above mentioned cycle is thereby repeated 0-5 times;

if a flow of water exceeding said certain threshold value is still detected, the program is terminated, and an outlet pump (18) belonging to the household appliance (2) is started; and in that

an error message starts to sound continuously at the same time as a display (19) shows an error message in plain text.