GB2067067A - Washing apparatus with water softening means - Google Patents

Abstract

Washing apparatus e.g. a dish-washing machine (10), is provided with water softening means comprising an ion exchanger (18), a duct (12) for supplying fresh water to the ion exchanger via valve (13), a water storage vessel (20) which is supplied with fresh water from duct (12) via duct (22) and has an overflow duct (23) and a discharge duct (24), and a salt container (26) connected to the water storage vessel by duct (24) and valve (25) and to the ion exchanger (18) by duct (28) and valve (29). The arrangement is such that the water storage vessel is filled rapidly with water to the level of the overflow duct when valve (13) is opened to supply fresh water to the ion exchanger. It also prevents non-softened water passing directly from the storage vessel to wash chamber (11). <IMAGE>

Description

SPECIFICATION Washing apparatus with water softening means The present invention relates to water softening means for washing apparatus, especially a dishwashing machine.

In a known softening device (DE OS 25 01 269) for a disht-washing machine, an open-topped storage vessel collects leakage water which arises in the free flow region of a fresh water inlet duct when nonsoftened fresh water flows to an ion exchanger of the machine. The storage volume of the storage vessel is determined by an overflow line which conducts the excess of leakage water into the wash vessel of the dish-washing machine. The water stored in the storage vessel is held back until the machine control opens a valve situated in a brine duct in order to initiate a regeneration operation of the ion exchanger. Water now flows under gravity from the storage vessel into a salt container and conveys brine from the latter into the ion exchanger. After a sufficient dwell time, the consumed brine is expelled from the ion exchanger.

It is considered desirable for such a storage vessel to be capable of being rapidly and reliably filled with water, yet not to cause any non-softened water to pass from the storage vessel into the wash vessel of the dish-washing machine.

According to the present invention there is provided washing apparatus provided with water softening means comprising an ion exchanger, a fresh water inlet duct for supplying fresh water to the ion exchanger, the inlet duct including an inlet valve, a closed water storage vessel, a supply duct connected between the storage vessel and the inlet duct for supplying fresh water from the inlet duct to the storage vessel, and overflow duct connected between the inlet duct upstream of the supply duct connection and the storage vessel for conducting overflow water from the storage vessel to the inlet duct, a salt container disposed below the storage vessel, a transfer duct for conducting water from the storage vessel to the salt container, and a valve-controlled brine duct for conducting brine from the salt containerto the ion exchanger.

In apparatus embodying the invention, because the supply duct is connected to the inlet duct at a place of higher pressure, while the overflow duct is connected at a place of lower pressure, a proportion of the water is thereby branched off, in a simple manner, through the supply duct, when fresh water is flowing to the ion exchanger. By means of this proportion of water, the storage vessel can be filled in a short time and the water that continues to flow into the vessel once filled is conducted back through the overflow duct into the flow to the ion exchanger.

Advantageously, the supply duct is arranged to lead into the upper end portion of the storage vessel.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawing, which is a schematic view of a dish-washing machine provided with water softening means in accordance with the said embodiment.

Referring now to the drawing, there is shown a dish-washing machine 10 comprising a wash vessel 11 and a mains-supplied fresh water feed line 12, in which is disposed a water inlet valve 13 controlled by the programme control device (not shown) of the machine. Further along the fresh water feed line 12 in the direction offlowofwatertherein are, in succession, a nozzle 14, a free flow region 15 for preventing suction of liquid back out of the machine 10, and a diffusor 16. Leakage water that arises when fresh water flows in the free flow region 15 is conducted by a leakage water line 17 into the wash vessel 11 of the dish-washing machine 10.From the diffusor 16, which serves for raising the flow pressure of the fresh water after this pressure has fallen in the free flow region 15, the fresh water feed line 12 leads to an ion exchanger 18, which is disposed below the wash vessel 11 and has an outlet pipe 19 leading into the wash vessel 11.

The dish-washing machine 10 also possesses a vessel 20 for the storage of a fixed quantity of water which, as will be explained below, serves for preparing the brine required for the regeneration of the ion exchanger 18. The water storage vessel 20 is closed on all sides and is connected at its upper end portion 21 to the fresh water feed line 12 by a supply line 22 branching from the feed line 12 downstream in the direction of flow from the diffusor 16 and by an overflow line 23 leading back into the feed line. Although the two lines 22 and 23 are situated close together at their ends adjacent the vessel 20, they are at some distance apart at their ends adjacent the feed line 12, the supply line 22 branching from the feed line several centimetres below the inlet of the overflow line 23 into the feed line.From the water storage vessel 20, which is disposed in the upper region of the dish-washing machine 10, a discharge line 24 with a regeneration valve 25 leads from the bottom of the storage vessel to a salt container 26 which, like the ion exchanger 18, is located below the wash vessel 11 in the lower zone of the dish-washing machine 10.

The salt container 26 and the ion exchanger 18, which together basically constitute a softening device 27 of the dish-washing machine 10, are connected together by a brine line 28 containing a valve 29.

During the course of a washing programme in the dish-washing machine 10, during each programme section for cleaning or rinsing crockery, the water inlet valve 13 controlled by the programme control device is opened so that fresh water softened in the ion exchanger 18 flows into the wash vessel 11, as indicated by the arrows drawn in solid lines. By optimum construction of the nozzle 14 and diffusor 16 and by appropriate design of the free flow region 15, only a small quantity of non-softened leakage water occurs in this free flow region when fresh water is flowing to the ion exchanger 18, this leakage water flowing through the leakage water line 17 into the wash vessel 11 of the dish-washing machine 10 in the direction of the arrow shown as a dotted line.

On the inflow of fresh water, a proportion of this is branched from the feed line 12 through the supply line 22 and the water storage vessel 20 is filled in a very short time. The air expelled from the storage vessel 20 by the water passes through the overflow line 23 into the diffusor 16, where it is entrained by the fresh water. When the water storage vessel 20 is filled, any fresh water continuing to flow into the vessel is conducted via the overflow line 23 back into the feed line 12 and then via the feed line 12 to the ion exchanger 18 (dot-and-dash arrows in the region of the supply line 22 and overflow line 23). This filling operation is achieved as a result of the fact that, at the branch of the supply line 22 from the feed line 12, a slightly higher pressure is present in the column of water in the feed line than at the connection of the overflow line 23.

An outflow of the quantity of water stored in the storage vessel 20 is prevented at this time because the valve 25 in the discharge line 24 is kept closed by the programme control device of the dish-washing machine 10. The exact storage volume or filled level of the water storage vessel 20 is determined, in the illustrated example, by the position of the connection of the supply line 22 to the vessel, as when the water feed to the ion exchanger 18 is terminated, the water level in the feed line 12 falls as a result of venting through the free flow region 15 and thus a portion of the water flows out from the vessel through the supply line into the feed line, until the water level identified by a mark 30 is established.

During the further course of the washing programme, the programme sections including the flow of fresh water to the ion exchanger 18 are followed by a further section for regenerating the ion exchanger. During and only during this programme section the valves 25 and 29, controlled by the programme control device of the dish-washing machine 10, are simultaneously opened. The water collected in the storage vessel 20 flows under gravity through the discharge line 24 into the salt container 26. The venting of the vessel 20 is provided by the free flow region 15, the diffusor 16 and the overflow line 23.

Brine is expelled from the salt container 26, and flows through the brine line 28 into the ion exchanger 18 (dot-and-dash arrows at the lines 24 and 28). The measured water flow from the storage vessel 20 ensuresthatthe ion exchanger 18 is completely filled with brine. After a sufficient dwell time of the brine in the ion exchanger 18, the programme control device opens the water inlet valve 13, while the valves 25 and 29 are now closed, so that fresh water flows through the feed line 12 into the ion exchanger 18 and expels the consumed brine through the outlet pipe 19 into the wash vessel 11 of the dish-washing machine 10.

Claims (4)

1. Washing apparatus provided with water softening means comprising an ion exchanger, a fresh water inlet duct for supplying fresh water to the ion exchanger, the inlet duct including an inlet valve, a closed water storage vessel, a supply duct con nected between the storage vessel and the inlet duct for supplying fresh water from the inlet duct to the storage vessel, an overflow duct connected between the inlet duct upstream of the supply duct connection and the storage vessel for conducting overflow water from the storage vessel to the inlet duct, a salt container disposed below the storage vessel, a transfer duct for conducting water from the storage vessel to the salt container, and a valve-controlled brine duct for conducting brine from the salt containerto the ion exchanger.

2. Apparatus as claimed in claim 1, wherein the supply duct is connected to the storage vessel in the uppererrd region thereof.

3. Apparatus as claimed in either claim iprclaim 2, the apparatus being a dish-washing machine.

4. Washing apparatus provided with watersoftening means substantially as hereinbefore described with reference to the accompanying drawing.