DE8420779U1 - Level control and safety device for water-conducting household appliances - Google Patents

Description

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BOSCH-SIEMENS HOUSEHOLD APPLIANCES GMBH S Munich 80, 2L07.19Sd

Hochstrasse 17

AmtLAktz.: G 84 20 779.5 TZP 84/314 Ul/si Level control and safety device for water-conducting household appliances.

The innovation concerns a level control and safety device for water-conducting household appliances according to the generic term of claim 1.

A safety device against flooding in liquid-carrying household appliances is known (DE-PS 30 14 427), with an inlet hose connected to a shut-off valve of a water supply network via a machine-controlled inlet valve and a leakage water collecting tray arranged on the bottom of the appliance with a switching device located in it, which blocks the liquid inlet if leakage water occurs. For an effective

Official reference number: G 84 20 779.5 TZP 04/314

To protect against flooding in the event of a hose break, this safety device has a leakage water hose that extends from the inlet valve, envelops the inlet hose and flows freely into the leakage water collecting tray. The switching device of the collecting tray and the inlet valve on the shut-off valve are connected by a control line.

The innovation is based on the task of designing a level control and safety device of the type mentioned above in such a way that it enables effective protection against flooding in the event of a hose rupture without the additional use of valves and control devices.

This task is solved by the features identified in claim 1. As the mechanically permanent magnet-operated shut-off valve is provided for level control, while the controlled water inlet solenoid valve, which can be switched with a time overlap, forms the safety part, the overall device can be simplified considerably without negatively affecting the accuracy of the level control or the safety against overfilling of the tub, since a second air trap chamber for a safety level, with an overflow edge and suction lifter, as well as an operating level monitor - the function of which is taken over by the pressure box of the shut-off valve - with its contacts and connections are omitted. According to the innovation, the mechanically permanent magnet-operated shut-off valve is attached to the shut-off tap of the fixed water supply network, while the program-dependently switchable solenoid valve is located at the end of the inlet hose in the household appliance. The shut-off valve without an electrical sensor takes over the filling control of the water in the tub and at the same time protects the household appliance against water leakage. If the shut-off valve malfunctions, the time-controlled solenoid valve prevents the tub from overfilling. In addition, depending on the design of the level control vessel and the opening time of the solenoid valve after the shut-off valve is closed, the water and the associated pressure drop when the circulation pump starts up when the shut-off valve is closed can cause the water to drop below the set pressure.

- 3 Official File G 84 20 779.5 TZP 84/314

riet opens due to the pressure drop at its pressure box, dynamic refilling of water into the tub is possible. Since the shut-off valve on the stopcock is always closed when the tub is filled with water up to the filling level, it contributes to level control of the tub and to protecting the inlet hose.

A particularly advantageous device according to the innovation, which provides effective protection against flooding in the event of a hose rupture, is characterized in that a leakage water hose enveloping the inlet hose extends from the permanent magnet-operated shut-off valve and flows into a leakage water collecting tray arranged on the bottom of the household appliance, which has a switching device which blocks the liquid inlet if leakage water occurs.

Another embodiment, which also does not require a collecting tray arranged on the bottom of the device, is characterized in that a leakage water hose is provided between the permanent magnet-operated shut-off valve attached to the shut-off tap and the water inlet electronic solenoid valve on the machine side, which surrounds the inlet hose, and that the annular space between the inlet and leakage water hose is connected to the pressure box of the shut-off valve via a line.

The connection of the household appliance is made easier if the inlet hose, the leakage water hose, the control line from the level control vessel to the pressure box of the shut-off valve and, if applicable, the drain hose leading from the drain pump to the sewer are combined into one hose line.

The innovation is explained below using _the examples shown in the drawing.

It shows

Fig. 1 shows a simplified representation of a dishwasher, which is connected by a hose to a permanent magnet-operated shut-off valve located on the stationary shut-off valve of the water supply network,

AmtLAktr.: G 84 20 779.5

TZP84/314

Fig. 2 a permanent magnet actuated shut-off valve with pressure cell in section.

The dishwasher 1 has a tub 2 and a drain pan 3 arranged on the bottom of the tub. The water supply to the dishwasher comes from a water pipe network with a stationary shut-off valve 4, to which the inlet connection 6 of a mechanically permanent magnet-operated shut-off valve 7 - as is known, for example, from DE-PS 31 14 664 - is attached by means of a union nut 5. An inlet hose 9 leads from the outlet connection 8 of the shut-off valve 7 to a machine-specific program-controlled water inlet solenoid valve 10 and from there via a water inlet vessel 11 to the tub 2.

To monitor a normal filling level 12, a level control vessel 14 is connected to the tub or its drain pan 3 via a nozzle 13. This vessel has a pressure or air trap chamber 15 with an overflow edge 16 at the height of the normal filling level and a suction lifter 17 provided for emptying the pressure chamber. The pressure chamber is connected via a control line 18 to a pressure cell 19 of the shut-off valve on the shut-off cock 4. The shut-off valve has a permanent magnet 21 located on a membrane 20 of the pressure cell, an armature 22 of the shut-off valve, a valve-side membrane 23, a servo bore 24 and a spring 25.

The level control and safety device works as follows:

If the household appliance is operating properly and the tub is empty, the shut-off valve 7 on the shut-off tap is open and the water inlet solenoid valve 10 of the machine is closed. The water is fed into the tub 2 by opening the water inlet solenoid valve 10, which is switched by the program control. When the normal filling level is reached

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- 5 ArotLAktz.: G 84 20 779.5 _{TZp 82/314}

In the tub 2, a small amount of water overflows through the level control vessel 14, which is connected to it, via the
overflow edge 16 into the pressure chamber 15. A small amount of water is sufficient
to build up a pressure in the air trap chamber 15 that exceeds the
Control line 18 pressurizes the pressure cell 19 of the shut-off valve 7 in such a way that the shut-off valve is moved into its closed position and
blocks the further inflow of water. This also protects the inlet hose 9 against hose breakage. The water inlet solenoid valve 10, which is switched via a timer of the device control, is
Expiry of its specified opening hours also closed.

When the tub is emptied and/or after the circulation pump is switched on, the water level is lowered and the siphon 17 can be used to

Emptying of the pressure chamber 15, whereby the pressurization f

the pressure cell 19 is removed and the shut-off valve 7 is returned to its open position. |

position. Due to this mode of operation of the mechanically permanent I

The solenoid operated shut-off valve prevents the valve from seizing

In addition, depending on the design of the level control vessel and S

the opening time of the water inlet solenoid valve 10 after the on- I

the circulation pump is running when the shut-off valve 7 opens again, a \

Dynamic refilling of water into the tub possible. ?

If due to a fault, e.g. blockage of the level control vessel or I

Failure of the pressure vessel, the water supply to the tub when the &iacgr;

normal filling level 12 is not interrupted, the tub still flows |

long water until the opening time of the water inlet solenoid valve X

10 expires. This opening time can be designed so that in the event of a safety emergency, the tub only rises slightly above the normal filling level

is filled beyond. j

&Idigr; In order to detect leaks in the tub or in the other water-carrying components of the household appliance, the level control and safety features

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Official reference: G «4 20 779.5 TZP 84/314

In order to control the direction of flow, leakage water can be collected in a collecting tray (not shown) on the floor. A switching device is assigned to the collecting tray, which can be coupled to the pressure cell 19 of the shut-off valve 7 in such a way that it causes the shut-off valve to close even when there is a small amount of leakage water in the collecting tray.

The inlet hose 9 can advantageously form a hose line 26 with the control line. This hose line can be supplemented by a leakage water hose that surrounds the inlet hose 9, is attached to the shut-off valve 7 and opens into a leakage water collecting tray of the device, or it can also include the drain hose that leads from the machine's drain pump to the waste water connection. Effective protection against flooding in the event of a hose breakage is possible via the leakage water hose that surrounds the inlet hose and the switching device that closes the shut-off valve 7 when leakage water occurs.

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Claims (4)

BOSCH-SIEMENS HOUSEHOLD APPLIANCES·" CJMB'H ,·, .·. ' ^,&lgr;/fonahen 80, 07.11.1986 Hochstraße 17 AmtLAktz.: G 84 20 779.5 TZP 84/314 Ul/si Protection claims 1. Level control and safety device for water-conducting household appliances, in particular for program-controlled dishwashers and washing machines, with an inlet hose between a machine-controlled valve which is assigned to a shut-off valve of a water supply network and a further valve at the machine-side inlet hose end, characterized in that a shut-off valve (7) with a permanent magnet (21) and a pressure box (19) is arranged on the shut-off valve side of the inlet hose (9), that the permanent magnet holds the shut-off valve in the open position in the rest position, that the pressure box is connected to a filling level (12) of the tub (2) set pressure chamber (15) via a control line (18), that the shut-off valve assumes the closed position at the filling level (12) of the tub, that a water inlet solenoid valve (10) connected to a timer of the program control unit is arranged at the machine-side inlet hose end, that the pressure chamber (15) is provided in a level control vessel (14) connected to the drain pan (3) or to the emptying system of the tub (2) in a fluid-conducting manner, and that an arch of a suction lifter (17) is arranged at the level of the normal filling level (12) of the tub and at the same time forms an overflow edge (16) between the tub and the pressure chamber. 2. Device according to claim 1, characterized in that a leakage water hose extending from the shut-off valve (7) with permanent magnets (21) surrounds the inlet hose (9), that the leakage water hose opens on the machine side into a leakage water collecting tray arranged on the bottom side of the household appliance and that a switching device which responds to leakage water is provided in the leakage water collecting tray. III III· · · · · till &igr; · · * · · « I 11*11 ■ · · t t ··· t · frf * TZP84/314 3. Device according to claim 1, characterized in that a leakage water hose enclosing the inlet hose is provided between the shut-off valve with permanent magnets attached to the inlet hose on the shut-off tap side and the water inlet solenoid valve attached to the inlet hose on the machine side, and that the annular space between the inlet and leakage water hoses is connected to the pressure box of the shut-off valve via a line. 4. Device according to one of claims 1 to 3, characterized in that the inlet hose (9), the leakage water hose and the safety line (18) from the level control vessel (14) to the pressure cell (19) of the shut-off valve (7) are combined to form a hose strand (26). ■ ■ * tilt ittl * t