GB2174138A

GB2174138A - Improvements in storage tanks and cisterns and covers therefor

Info

Publication number: GB2174138A
Application number: GB08510454A
Authority: GB
Inventors: William Geraint Turner; Leslie Loosemore
Original assignee: FLEXTANK Ltd
Current assignee: FLEXTANK Ltd
Priority date: 1985-04-24
Filing date: 1985-04-24
Publication date: 1986-10-29
Also published as: GB2174138B; GB8510454D0

Abstract

A cover 15 for a cistern has a main cover portion 16 from which extends an outwardly flared peripheral flange 17. The flange 17 has a peripheral channel 18 opening generally inwardly for engagement by a rim 13 of the cistern 10. An outwardly flared skirt 19 depends from the channel 18, the arrangement being such that the channel 18 engages the rim 13 with a snap fit. <IMAGE>

Description

SPECIFICATION Improvements in storage tanks and cisterns and covers therefor The invention relates to covers for storage tanks or cisterns, more particularly but not exclusively for domestic cisterns. The term "cisterns" used hereinafter will refer to storage tanks and cisterns.

Hitherto, cisterns have generally been made either of galvanized iron or steel, or more recently from plastics material such as polypropylene. Covers for such cisterns have in the past simply rested on the rim of the cistern and a problem associated with such an arrangement is that foreign bodies are able to find their way into the cistern.

Recent revisions in the model water byelaws require that all cisterns which are supplied to new installations must comply with drinking water standards, namely that all foreign bodies having a diameter greater than 0.6mm must be excluded.

Covers need to be fixed firmly in place, and yet be easily removable for inspection; this causes a problem for cisterns not found in small domestic containers.

According to the invention there is provided a cistern and a cover therefor, the cistern having a base, side walls extending from the base and an upper circumferential rim having a portion extending outwardly of the side walls, the cover having a peripheral channel adapted to receive the rim of the cistern, an outwardly flaring skirt depending from the channel for engagement by the rim when fitting the cover on the cistern whereby, through flexure of the rim of the cistern and the channel and skirt of the cover, the cover is located onto the rim with a snap fit.

It will be appreciated that the term "side walls" includes in its scope a cylindrical side wall.

The peripheral channel may have an inner surface and the rim a corresponding outer surface which in cross-section are curved, for example part circular.

The channel preferably opens substantially inwardly so that, in use, the channel surrounds the rim of the cistern.

The channel may open in a direction having a component extending away from the general plane of the cover.

The cover may be generally circular.

The channel may be located in a peripheral flange of the cover, and the peripheral flange may be frustoconicai.

There may be a screened ventilator in the cistern or lid.

By way of example, one embodiment of a cistern and a cover therefor according to the invention will now be described with reference to the accompanying drawing which is a sectional view of a cover located on a cistern rim.

A cistern 10, suitably made of polypropylene or polyethylene has a side wall 11 which is approximately cylindrical. A reinforcing profile 12 is provided to assist rigidity of the wall 11.

At the top of the wall 11, a rim profile 13 is provided which in cross-section approximates to a hook shape to provide an annular rim surface of larger dimensions than the diameter of the side wall 11.

Mounted on the cistern 10 is a cover 15 having a generally planar main cover portion 16 from which extends a peripheral flange 17 which is flared outwardly with respect to the main cover portion 16.

The flange 17 includes a peripheral channel 18 which opens generally inwardly but at an angle to the general plane of the cover 15. The channel 18 has, in cross-section, a curved inner wall.

Depending from the channel 18 is an outwardly flared skirt 19 and it will be appreciated that, when it is desired to locate the cover 15 on the cistern 10, the rim 13 first engages the skirt 19 to force outwardly a neck 20 between the channel 18 and the skirt 19 and to force inwardly the rim 13 until the rim 13 snaps into the channel 18.

It will be appreciated that the cover 15 is also suitably of polypropylene or polyethylene.

This particular embodiment of cistern 10 and cover 15 is generally circular but it will be appreciated that other shapes may be used.

This embodiment of a cistern and cover according to the invention allows tight fitting of the cover 15 to the rim 13 with a snap fit, together with easy removal of the cover for inspection purposes. The skirt 19 allows sufficient finger leverage not only to deform the neck 20 outside the rim 13 but to cause the inner lip of the rim 13 to be deformed outwardly to facilitate removal.

1. A cistern and a cover therefor, the cistern having a base, side walls extending from the base and an upper circumferential rim having a portion extending outwardly of the side walls, the cover having a peripheral channel adapted to receive the rim of the cistern, an outwardly flaring skirt depending from the channel for engagement by the rim when fitting the cover on the cistern whereby, through flexure of the rim of the cistern and the channel and skirt of the cover, the cover is located onto the rim with a snap fit.

2. A cistern and cover as claimed in Claim 1 wherein the peripheral channel has an inner surface and the rim a corresponding outer surface which in cross-section are curved.

3. A cistern and cover as claimed in Claim 2 wherein the inner surface of the channel and outer surface of the rim are part circular in cross-section.

4. A cistern and cover as claimed in any preceding Claim wherein the channel opens substantially inwardly so that, in use, the channel surrounds the rim of the cistern.

5. A cistern and cover as claimed in Claim 4 wherein the channel opens in a direction having a component extending away from the general plane of the cover.

6. A cistern and cover as claimed in any preceding Claim which is generally circular.

7. A cistern and cover as claimed in any preceding Claim wherein the channel is located in a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in storage tanks and cisterns and covers therefor The invention relates to covers for storage tanks or cisterns, more particularly but not exclusively for domestic cisterns. The term "cisterns" used hereinafter will refer to storage tanks and cisterns. Hitherto, cisterns have generally been made either of galvanized iron or steel, or more recently from plastics material such as polypropylene. Covers for such cisterns have in the past simply rested on the rim of the cistern and a problem associated with such an arrangement is that foreign bodies are able to find their way into the cistern. Recent revisions in the model water byelaws require that all cisterns which are supplied to new installations must comply with drinking water standards, namely that all foreign bodies having a diameter greater than 0.6mm must be excluded. Covers need to be fixed firmly in place, and yet be easily removable for inspection; this causes a problem for cisterns not found in small domestic containers. According to the invention there is provided a cistern and a cover therefor, the cistern having a base, side walls extending from the base and an upper circumferential rim having a portion extending outwardly of the side walls, the cover having a peripheral channel adapted to receive the rim of the cistern, an outwardly flaring skirt depending from the channel for engagement by the rim when fitting the cover on the cistern whereby, through flexure of the rim of the cistern and the channel and skirt of the cover, the cover is located onto the rim with a snap fit. It will be appreciated that the term "side walls" includes in its scope a cylindrical side wall. The peripheral channel may have an inner surface and the rim a corresponding outer surface which in cross-section are curved, for example part circular. The channel preferably opens substantially inwardly so that, in use, the channel surrounds the rim of the cistern. The channel may open in a direction having a component extending away from the general plane of the cover. The cover may be generally circular. The channel may be located in a peripheral flange of the cover, and the peripheral flange may be frustoconicai. There may be a screened ventilator in the cistern or lid. By way of example, one embodiment of a cistern and a cover therefor according to the invention will now be described with reference to the accompanying drawing which is a sectional view of a cover located on a cistern rim. A cistern 10, suitably made of polypropylene or polyethylene has a side wall 11 which is approximately cylindrical. A reinforcing profile 12 is provided to assist rigidity of the wall 11. At the top of the wall 11, a rim profile 13 is provided which in cross-section approximates to a hook shape to provide an annular rim surface of larger dimensions than the diameter of the side wall 11. Mounted on the cistern 10 is a cover 15 having a generally planar main cover portion 16 from which extends a peripheral flange 17 which is flared outwardly with respect to the main cover portion 16. The flange 17 includes a peripheral channel 18 which opens generally inwardly but at an angle to the general plane of the cover 15. The channel 18 has, in cross-section, a curved inner wall. Depending from the channel 18 is an outwardly flared skirt 19 and it will be appreciated that, when it is desired to locate the cover 15 on the cistern 10, the rim 13 first engages the skirt 19 to force outwardly a neck 20 between the channel 18 and the skirt 19 and to force inwardly the rim 13 until the rim 13 snaps into the channel 18. It will be appreciated that the cover 15 is also suitably of polypropylene or polyethylene. This particular embodiment of cistern 10 and cover 15 is generally circular but it will be appreciated that other shapes may be used. This embodiment of a cistern and cover according to the invention allows tight fitting of the cover 15 to the rim 13 with a snap fit, together with easy removal of the cover for inspection purposes. The skirt 19 allows sufficient finger leverage not only to deform the neck 20 outside the rim 13 but to cause the inner lip of the rim 13 to be deformed outwardly to facilitate removal. CLAIMS

7. A cistern and cover as claimed in any preceding Claim wherein the channel is located in a peripheral flange of the cover.

8. A cover as claimed in Claim 7 wherein the peripheral flange is frustoconical.

9. A cistern and cover as claimed in any preceding Claim including a screened ventilator.

10. A cistern and cover substantially as hereinbefore described with reference to and as shown in the accompanying drawing.