Detergent dispenser system

Details Detergent dispenser system Detergent dispenser system

2002-01-23

2004-03-09

Stinson, Frankie L. (Department: 1746)

Cleaning and liquid contact with solids

Apparatus

With solid agent dissolving or supplying means

C134S094100, C134S201000, C137S268000

Reexamination Certificate

active

06701944

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a dishwasher detergent dispenser system and in particular to a system for the controlled delivery of detergent in tablet form to a dishwasher.
BACKGROUND TO THE INVENTION
Various proposals have been made to incorporate a storage unit in to a dishwasher for storing a plurality of detergent tablets to avoid the necessity of the user to recharge the dishwasher with detergent for each washing cycle. Examples of such devices are disclosed in DE 19620088, 19636497 and 129615674.
CA 2189115 discloses a dishwasher comprising a dispensing arrangement for the programmed delivery of cleaning agents in tablet form. The dispensing arrangement includes a storage unit for storing the detergent tablets, a separating device for removing at least one detergent tablet from the storage unit and a lock chamber. The lock chamber separates the detergent tablets stored in the storage unit from the damp ambient conditions of the washing chamber in the dishwasher. The detergent tablets are stored in several stacks in order that minimise space and the separating device can be arranged to remove a predetermined number of detergent tablets from the storage unit.
There are various problems associated with the design of a detergent dispensing system for a dishwasher. The dispensing system should have a storage unit capable of holding sufficient detergent for several wash cycles. The detergent in the storage unit must be completely protected from the damp conditions prevailing in the dishwasher since the detergent will form a solid mass when exposed to moisture. The dispensing device must have an effective means of transferring detergent from the storage unit to the dishwasher. Ideally, the dispensing device should dispense the detergent at the appropriate time at the washing cycle.
Known dispensing devices for detergent tablets have employed detergent tablets having a diameter of at least 24 mm. In some devices the tablets have been arranged in one or more vertical stacks or columns with the circular faces of adjacent tablets in contact with one another. One of the problems associated with this arrangement is that the surface of the tablets is rough because of the granular nature of the detergent and the device for removing a tablet from the stack must be able to overcome the high frictional forces between adjacent tablets. DE 19620088 discloses a dispensing device in which the tablets are stored in a serpentine channel such that adjacent tablets touch circumferentially. However, this arrangement is wasteful of space.
It is an object of the present invention to provide an improved detergent dispensing system from a multitablet storage unit suitable for use in a dishwasher.
BRIEF SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a removable cartridge for a detergent dispensing system e.g. for a dishwasher, comprising:
a storage unit containing a plurality of cylindrical or spherical detergent tablets arranged in two or more rows with curved surfaces of adjacent tablets touching such that when the cartridge is upright the tablets will move under gravity towards a transfer station,
a transfer station comprising ejection means to eject a tablet from the transfer station through a transfer port out of the cartridge and,
a transfer seal associated with the transfer port to prevent ingress of moisture into the cartridge.
According to a second aspect of the invention there is provided a detergent dispensing system e.g. for a dishwasher, comprising a cartridge as described above and a dispensing chamber having an inlet in communication with the transfer port of the cartridge and an outlet which may be sealed by a door.
The invention provides an effective detergent dispensing system suitable for use in a dishwasher, laundry washing machine etc., which may contain sufficient detergent tablets for many wash cycles e.g. at least ten, preferably at least thirty, which is simple to operate on the part of the user. In preferred embodiments, once the cartridge is in place the user simply selects the desired wash programme and the dishwasher dispense the correct number of tablets at the appropriate time during the wash cycle.
DESCRIPTION OF PREFERRED EMBODIMENTS
The detergent dispensing device of the invention is preferably positioned within the door of the dishwasher thereby does not encroach on any of the volume within the cleaning chamber. Also, it allows the user ready access for the replacement of the cartridge.
An essential component of the detergent dispensing system is a removable cartridge. The cartridge contains the detergent tablets and comprises a mechanism to eject the tablets from the cartridge. The cartridge also has a seal to prevent moisture ingress in to the storage area. The seal is important since ingress of moisture is likely to cause adjacent tablets to agglomerate causing them to jam in the storage unit. Preferably, the entire cartridge is replaced when it is emptied and thus the transfer mechanism and seal will be replaced when a new cartridge is in place. This feature is desirable since it obviates the need to utilise a transfer mechanism and seal which will last the life of the dishwasher and furthermore it reduces the routine maintenance required to keep the dishwasher in perfect running order.
The cartridge utilises spherical or cylindrical detergent tablets. References to detergent tablets herein refer not only to detergent tablets but also to tablets composed of other dishwashing active ingredients e.g. water softeners and rinse aids. The tablets are formed by compaction or pressure moulding of powdered ingredients in a conventional manner.
The spherical tablets preferably have a diameter in the range 10 to 20 mm. The cylindrical tablets used in the cartridge preferably have a diameter in the range 10 to 20 mm and a length which is at least 10% different to the diameter. The reason for the difference in length is to prevent the tablets rotating out of alignment in the rows within the dishwasher. A preferred cylindrical tablets has a diameter of about 17 mm and a length of about 12 mm. The edge between the circular face and cylindrical surface desirable chamfered since this assists in the manufacture of the tablets by compression moulding and also reduces the propensity of the tablets to chip during transportation and storage.
The tablets are arranged in the cartridge in substantially vertical rows when the cartridge is in its upright position. The storage unit comprises a sloping floor or glides to direct tablets towards the transfer station. The transfer station can be at one corner of the cartridge in which case the floor will slope towards that corner. Alternatively, the transfer station may be located spaced from a corner in which case the sloping floor may be in the form of a funnel.
Adjacent rows of tablets are preferably separated by guides which are spaced apart slightly more than the diameter of the cylinder or sphere of the detergent tablets. The use of guides is particularly advantageous since it prevents lateral displacement of the tablets and reduces movement of the tablets when the door of the dishwasher is repeatedly opened and closed. Thus, as well as controlling the orientation of the tablets the guides reduce the propensity of the tablets to impact violently upon each other which could cause breakage of tablets resulting in incorrect dosing or the tablets jamming in the cartridge.
In one embodiment of the invention the storage unit is divided in to two halves by a central wall such that there are two sets of tablets arranged in respective sets of rows. Each set of tablets is associated with its own ejection means.
The tablets may be ejected from the cartridge by any suitable mechanism. For example, the transfer station may simply comprise a door or shutter which is opened for a pre-determined length of time to allow one or more tablets to drop from the storage station out of the cartridge through the transfer port. Alternatively, the transfer station may comprise a plunger or piston which pushes

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