GB2113255A

GB2113255A - Supply of metered quantities of a washing additive in a washing or dishwashing machine

Info

Publication number: GB2113255A
Application number: GB08227957A
Authority: GB
Inventors: Anton Heyne
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-12-16
Filing date: 1982-09-30
Publication date: 1983-08-03
Also published as: GB2113255B; FR2518138A1; IT8224610A1; DE3149851A1; IT1153364B; FR2518138B1; IT8224610A0

Abstract

Supply means for a washing or dishwashing machine serves to supply a pumpable washing additive from a supply container 1 by means of a pump 2 to a washing or rinsing container 7 of the machine in such a manner that it meters an accurate metered quantity which remains the same independently of the viscosity of the additive. The outlet of the pump 2 opens through a valve 3, which has a piston 32 guided in the valve housing 31 and raisable by the pump pressure, into a metering container 4 with an overflow duct 50 connected to the supply container 1. The piston 32 has a first opening 36 which, in raised setting of the piston, connects the metering container 4 with the pump outlet, and a second opening 35 which is fluid-tightly separated from the first opening and which, in lowered setting of the piston, connects an outflow channel 5 of the metering container 4 with a duct 6 leading to the washing or rinsing container 7. The base of the metering container 4 is arranged to be higher than the maximum permissible liquor level of the washing or rinsing container 1. A displaceable body 42 enables setting of a desired metered quantity. In a modification, the piston 32 is movable in a horizontal direction and a helical restoring spring is housed in a chamber 371. <IMAGE>

Description

SPECIFICATION Supply of metered quantities of a washing additive in a washing or dishwashing machine The present invention relates to a washing or dishwashing machine with supply means for supplying metered quantities of a flowable washing additive to a washing or rinsing compartment of the machine.

Washing or dishwashing machines of that kind, in which metering equipment for a pumpable washing additive is installed, are known. This metering equipment withdraws a measured quantity of a pumpable washing additive from a supply container and conveys this by means of a pump into the machine washing or rinsing container.

The known types of metering equipment prepare metered quantities as accurately as possible by means of several mechanical devices (pistons, valves) which are interconnected to have numerous relative movements. Since pumpable washing additives in the long term jell, crystallize or encrust under exposure to air, there is the risk of interruption of the operation of the mechanical metering equipment due to obstruction between mutually moving parts.

Other types of metering equipment, which operate by means of time-controlled pumps, have the disadvantage of inaccurate metering if the viscosity of the washing additive departs from the valve forming the basis of the design of the metering equipment.

The flow speeds of the washing additives vary through reduction or increase in the internal friction, so that for a fixed operating duration of the pump a higher metered quantity than desired results at lower viscosity and a lower metered quantity than desired results at higher viscosity.

There is accordingly a need for a washing or dishwashing machine with metering equipment which on the one hand ensures that the metered quantity remains constant and on the other hand reduces the danger of operational interruption due to thickening of the washing additive.

According to the present invention, there is provided a washing or dishwashing machine with supply means for supplying metered quantities of a flowable washing additive to a washing or rinsing compartment of the machine, the supply means comprising storage means for storing the additive, a metering chamber for metering the additive for supply to the compartment and being disposed with its base higher than a predetermined level for liquid in the compartment, a pump for pumping additive from the storage means to the metering chamber, an overflow duct for conducting excess additive from the metering chamber back to the storate means, and a valve controlling communication of the pump with the metering chamber and of the metering chamber with the compartment and comprising a housing and a piston which is provided with a first and a second opening defining separate flow paths in the piston and which is guided in the housing to be movable between a first position in which an outlet of the pump is placed in communication with the metering chamber by way of the first opening and a second position in which the metering chamber is placed in communication with the compartment by way of the second opening, the piston being movable into the first position by the conveying pressure of the pump.

The metered volume can be set to a desired value by the operator of the machine by means of a displacement body of settable immersion depth arranged in the metering chamber.

For preference the piston is arranged to be movable in a substantially vertical direction, but if conditions so require, the valve can be equipped with a horizontal piston which is held in its second position by the force of a spring.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawing, the single figure of which is a schematic sectional elevation of washing additive supply means in a washing or dishwashing machine embodying the invention.

Referring now the drawing, the supply means comprises a supply container 1 for a pumpable washing additive, for example a soft rinsing agent, the container being shown as open at the top, although in practice it would be formed with a refilling nozzle arranged at the top and a threaded cap in order that contact with the atmosphere is minimised but that refilling of the container is possible. The supply means further comprises a pump 2, here illustrated schematically as a toothed wheel pump, which is connected to a lower outflow of the container 1 and, at the pressure side, to a valve 3. The upper part of the valve opens into a metering container 4 to one side wall of which is connected an overflow duct 50 leading back to the container 1.The metering container 4 at its base 41 has an outflow channel 5, through which soft rinsing agent pumped into the metering container 4 is conducted through a duct 6 to a washing or rinsing container 7 of the machine.

The valve 3 comprises a valve housing 31 in which a piston 32 is vertically guided. The piston 32 consists of a downwardly open tube 33 closed off at the upper end portion by a head 34.

Arranged in the head 34 is a transverse bore 35 which, in the lowermost setting of the piston, is in alignment with the outflow channel 5. In the raised setting of the piston, which is illustrated in chain-dotted lines, a bore 36 through the wall of the tube 33 is moved above the base 41 of the metering container 4 so that the pressure side of the pump 2 communicates through the tube 33 and the bore 36 with the internal space of the metering container. A cylindrical enlargement 37, which has a lower shoulder 38 and an upper shoulder 39, is provided in the housing 31. A collar 331 at the lower end of the piston 32 cooperates with these shoulders in such a manner that the piston stroke is limited at the bottom by the shoulder 35 and at the top by the shoulder 39.

The collar 331 has unevenesses at its circumference to permit a flow of the rinsing agent from top to bottom or from bottom to top on each piston movement through the chamber 371 formed by the enlargement 37.

In operation, the pump 2 sucks soft rinsing agent out of the supply container 1 and conveys it towards the piston head 34, which then raises the piston 32 into the piston illustrated in chaindotted lines. In this position, the rinsing agent issues out of the bore 36 into the internal space of the metering container 4 and fills the container to the level of the overflow duct 50. In the raised setting of the piston, the outflow channel 5 is closed by the tube 33 of the piston 32. The pump 2 conveys rinsing agent into the metering container 4 for such time would be required to fill this with certainty up to the overflow level if the entire hollow space had to be filled. Excess rinsing agent escapes through the overflow duct 50 and is conducted back into the container 1.As soon as the pump 2 is stopped, the piston 32 sinks back, whilst the rinsing agent still present below the piston head is urged back through the leaky pump 2 into the container 1. When the piston 32 has sunk down completely and its collar 331 rests on the lower shoulder 38 of the enlargement 37, the transverse bore 35 is in alignment with the outflow channel 5 of the metering container 4 so that the content of the metering container flows through the outflow channel 5 into the container 7.

Also illustrated in the drawing is a displacement body 42, which is arranged in the metering container 4 and can be displaced to a greater or lesser depth into the metering container 4 by means of a threaded spindle 43 with a handle 44.

The body 42 is illustrated displaced so deeply that its entire volume is disposed below the overflow level. In this case, a lesser quantity of rinsing agent fills the metering container 4. The body 42 therefore enables setting of a desired metered quantity. When the body 42 extends less deeply or not at all below the overflow level, a larger metered quantity can be set.

For preference the pump is a type which exhibits some leakage losses in order that the rinsing agent can pass back into the container 1 on the lowering of the piston 32. In the case of use of a pump which does not display such leakage losses, care must be taken to permit a return flow by an artificial by-pass channel of small crosssection.

Insofar as it may be advisable for any reason to install the valve 3 in horizontal arrangement relative to the metering container 4, then in order to provide a restoring force acting on the piston 32. which in the illustrated embodiment is provided by gravity, the arrangement of a spring is necessary, for example a helical spring housed in the chamber 371 of the enlargement 37. The tube 33 and the enlargement 37 may then have to be prolonged by the length of the compressed spring.

By virtue of the overflow duct from the metering container, a metered quantity which remains the same is ensured in the case of an operating duration of the pump which is sufficient to ensure filling of the metering volume of the metering container with washing additive. The metering equipment of the described embodiment has a minimum of movable parts, merely a piston, so that the number of fault sources is reduced to a minimum.

Claims

1. A washing or dishwashing machine with supply means for supplying metered quantities of a flowable washing additive to a washing or rinsing compartment of the machine, the supply means comprising storage means for storing the additive, a metering chamber for metering the additive for supply to the compartment and being disposed with its base higher than a predetermined level for liquid in the compartment, a pump for pumping additive from the storage means to the metering chamber, an overflow duct for conducting excess additive from the metering chamber back to the storage means, and a valve controlling communication of the pump with the metering chamber and of the metering chamber with the compartment and comprising a housing and a piston which is provided with a first and a second opening defining separate flow paths in the piston and which is guided in the housing to be movable between a first position in which an outlet of the pump is placed in communication with the metering chamber by way of the first opening and a second position in which the metering chamber is placed in communication with the compartment by way of the second opening, the piston being movable into the first position by the conveying pressure of the pump.

2. A machine as claimed in claim 1, the supply means comprising a displacement body arranged in the metering chamber and adjustable in position to vary the metering volume of the chamber.

3. A machine as claimed in either claim 1 or claim 2, wherein the piston comprises a tubular body open at one end and closed at the other end by a head portion, the first and second openings being provided by respectively a first bore through the wall of the hollow portion of the tubular body and a second bore extending transversely through the head portion and the stroke of the piston being at least equal to the spacing of the distal edge of the first bore from the base of the metering chamber when the piston is in the second position thereof.

4. A machine as claimed in claim 3, wherein the piston is provided at its open end with a collar and the housing is provided in an enlargement thereof with two spaced apart internal shoulders each cooperable with the collar to limit travel of the piston in a respective direction.

5. A machine as claimed in claim 4, wherein the collar is provided with surface irregularities to permit flow of the additive past the collar.

6. A machine as claimed in either claim 4 or claim 5, wherein the collar is provided at a side thereof facing the openings with a sealing ring which sealingly engages a respective one of the shoulders when the piston is in its first position.

7. A machine as claimed in any one of the preceding claims, wherein the piston is arranged to be movable in a substantially vertical direction, the first position of the piston being above the second position thereof.

8. A machine as claimed in any one of the claims 1 to 6, wherein the piston is arranged to be movable in a substantially horizontal direction, spring means being provided to urge the piston into the second position thereof.

9. A washing or dishwashing machine substantially as hereinbefore described with reference to the accompanying drawing.