GB2210283A - Water filter - Google Patents

Abstract

A domestic water filter comprises a filter medium 2 in a cannister 1 which is mounted on a valve body 3 connected by a coupling member 8 to the fixed base of a household tap 13, replacing the movable parts thereof. The member 8 and body 3 provide respective paths, controlled by valve members 6,7, enabling water from tap 13 to flow through or bypass the filter medium. As shown filtered or unfiltered water is delivered to the tap spout, but filtered water could be delivered to a separate outlet in the cannister 1 or coupling member 8. <IMAGE>

Description

WATER FILTER This invention relates to a water filter for attaching to a household tap.

Hitherto, water filters for household use for improving the quality of drinking water have had either to be connected into the pipework of the water supply upstream of the household tap, or attached downstream either directly or by means of a flexible hose attachment to the tap's outlet spout.

Water filters connected upstream in the water supply require a convenient location and additional pipe fittings to complete the installation. Water filters attached to the outlet spout have the disadvantage that they require a secure pressure-tight connection which may be difficult to achieve on household taps.

The present invention relates to a filter for liquids comprising a cannister for containing a filter medium and a coupling member for coupling to theflxed part of a household tap, the coupling member providing a first flow path through the filter medium in the cannister and a second flow path which by-passes the said filter medium, at least the second flow path communicating with an outlet spout of the household tap.

Throughout this specification it will be understood that filtered water is that which has passed through the treatment media contained within the water filter and unfiltered water is that which is discharged from the tap and has not passed through the treatment media.

Two preferred-forms of water filter in accordance with the invention will now be described in detail, by way of example, with reference to the drawings in which: Figure 1 shows in section a first water filter in accordance with the invention; and Figure 2 shows in section a second form of water filter in accordance with the invention.

Figure 1 shows a water filter comprising a cylindrical filter cannister 1 enclosing replaceable treatment media 2. The treatment media may be of a proprietory form which has cleansing, filtering, adsorption or ion-exchange effects on water flowing through its bulk from the outside to an inner collecting chamber and terminating in a convenient discharge nipple. The treatment media is required to be cleaned or replaced when its function characteristics are exhausted.

The cannister 1 is releasably secured by threads or any other convenient coupling means to a valve body 3 and sealed to the valve body 3 by an 0-ring 4. The filter media 2 is also threaded at its lower end and screws into the valve body 3 and is sealed to it by a washer 5.

The valve body 3 contains valves 6 and 7 and is secured to a tubular coupling member 8 by, for example, screws, clamp or similar means (not shown). 0-rings 9 and 10 form a seal between the valve body 3 and coupling member 8. This arrangement allows the valve body 3 to be rotated about the vertical axis of the coupling member 8 and fixed in one of a number of angular positions.

In order to attach the filter to a household tap 13 the normal operating handle parts of the tap 13 are removed and the coupling member 8, which has matching thread, is screwed into the tap 13 and tightened on to a washer 11 to form a watertight joint with the tap seating face as a tap washer does in a conventional houshold tap.

The coupling member 8 and filter attached to it are held in place by a locking nut 12.

The means securing the valve body 3 to the coupling member 8 can then be released and the valve body 3 rotated to bring the valves 6 and 7 to a convenient position for an operator to use. The securing means are then tightened.

The coupling member 8 is formed with two concentric passages 20 and 21 extending through it from the tap body 13 to the valve body 3. The innermost passage 20 connects the tap inlet, through the washer 11, to a chamber 22 formed in the valve body 3. The chamber 22 has two outlet openings which can be opened or closed by means of the valves 6 and 7 respectively.

The two outlets from the chamber 22 controlled by the valves 6 and 7 open into two secondary chambers 23 and 24 formed in the valve body. The chamber 23, adjacent the valve 6, is connected to the interior of the filter cannister 1.

The outermost passage 21 formed in the coupling member 8 connects the outlet spout of the tap 13 through openings 14 formed in the periphery of the coupling member 8 to the chamber 23 formed in the valve body 3. The flow paths defined by the passages 20 and 21 are quite separate and do not communicate with one another except when connected by opening the valve 7.

To provide for a flow of unfiltered water, the valve 6 is closed and the valve 7 opened. Water rises up the innermost passage 20 of the coupling member 8 lifting a spring-loaded check valve 18 provided to prevent any back wash through the coupling member 8.

The water then flows through the chambers 22 and 24 and back down the outermost passage 21 through ports 14 aligned with the outlet spout of the tap.

To provide for a flow of filtered water the valve 7 is closed and the valve 6 is opened, allowing water to flow into the filter cannister 1 through the treatment media 2 and down through conduits (not shown) connecting the cavities A and B on Figure 1 and hence, through the outermost passage 21 of the coupling member and ports 14 to the tap outlet spout 13.

Preferably, however, the filtered water is discharged by a separate route and does not share the same passageways as the unfiltered water, thus eliminating any possibility of contamination.

In the embodiment shown in Figure 2, the water filter is provided with separate means to discharge filtered water in the form of an outlet spout 16. The inlet of the spout 16 is directly connected to the inner chamber of the treatment media 2a and the whole assembly is attached to and arranged to swivel about the vertical axis of the filter cannister 1. In other respects the filter of Figure 2 is similar to that of Figure 1 and similar compozEents are indicated by the use of the same reference numerals.

The check valve 18 mentioned above is provided to prevent siphoning or reverse flow of water as required by Water Authorities in the United Kingdom and is held closed by, for example, a spring weight or similar means (not shown) against a seating surface formed at the upper end of the innermost passage 20 of the coupling member 8. In the event of siphonic action occurring in the water supply upstream of the tap, the check valve 18 remains closed and acts as a non-return valve.

A graduated indicator ring 15 is provided around the periphery of the cannister 1 to give advance notice when the treatment media 2 needs cleaning or replacing. The ring is graduated in time intervals, for example, monthly units and is rotated at intervals around the vertical axis of the cannister 15 until two reference marks are aligned thus indicating that action is necessary.

It will be appreciated that although the term 'household tap' has been used throughout the specification, the invention can be applied to any tap having a fixed body with a valve seat intended to cooperate with a movable valve member carried by a removable portion of the tap body. The term 'household tap' is intended to include all such taps when used both in this description and in the claims appended hereto.

Claims (9)

1. A filter for liquids comprising a cannister for containing a filter medium and a coupling member for coupling to the fixed part of a household tap, the coupling member providing a first flow path through the filter medium in the cannister and a second flow path which by-passes the said filter medium, at least the second flow path communicating with an outlet spout of the household tap.

2. A filter according to claim 1 in which a separate outlet is provided for the first flow path.

3. A filter according to claim 1 or 2 in which first and second valve means are provided for controlling the flow of liquid through the first and second flow paths, respectively.

4. A filter according to claim 1, 2 or 3 in which at least a part of the first and second flow paths are arranged concentrically about one another.

5. A filter according to any preceding claim in which a first passage is common to the first and second flow paths and extends from the tap inlet to a chamber having two outlets leading to the first and second flow paths respectively.

6. A filter according to claim 5 in which resiliently-biassed check valve means is provided to oppose the flow of water from the said chamber towards the inlet of the tap.

7. A filter according to claim 2 in which the separate outlet is formed in-the coupling member.

8. A filter according to claim 2 in which the separate outlet is formed in the cannister containing the filter medium.

9. A filter substantially as hereinbefore described with reference to Figure 1 or 2 of the drawings.