GB2239318A - Device indicating loss of liquid - Google Patents

Abstract

A device (14) indicating loss of liquid from a body e.g. a fibrous card (12) is formed from a sheet of paper and has printing in the form of a star (16) on the underside thereof. A window (15) is suitably marked on the front face of the paper to clearly locate the position of the star, together with wordage (17) in the form of an instruction to a user. The device is in contact with the card (12) and the liquid wets it rendering it transparent and making the star visible. When liquid is lost from the card, the device also loses liquid, becoming opaque and resulting in the star no longer being visible. The card is inpregnated with solvent based liquid and gives off vapour useful for preventing paint on brushes etc hardening. <IMAGE>

Description

IMPEvOVEL.ENTS IN OR RELATING TO INDICATING DEVICES The present invention concerns improvements in or relating to indicating devices. More particularly, the present invention is concerned with indicating devices which indicate when a pad or card of fibrous or cellular material impregnated with a fluid has lost all, or nearly all, of the fluid through evaporation.

There are several situations when it is required to provide a solvent-based atmosphere within a closed housing.

For exampl6, a situation wherein paint brushes, rollers, pads or the like may be located in a closed housing and a solvent-based vapour is provided so as to prevent the pant on the brushes, rollers or pads from hardening. The device for permitting solvent vapour to pass into the atmosphere within the housing can be in the form of a pad or card cf fibrous or cellular material impregnated with the solvent-based fluid from which evaporation takes place. As solvent vapour is lost from the housing, for instance when the housing is opened in order to remove or replace a paint brush, eventually all or nearly all of the fluid on the pad or card will be lost by evaporation and a new impregnated pad or card refill will be required.

It is in the nature of an impregnated pad or card that as it approaches a dry condition it is most difficult to ascertain when all or substantially all of the fluid has evaporated.

It is an object of the present invention tc provide an indicating device to indicate to the user when a new ,impregnated pad or card refill is required.

According to the present invention there is provided an indicating device for indicating when a pad or card impregnated with solvent-based material requires replacing; said device comprising a sheet member having printing thereon on at least one face, namely the back face, and this face being in contact with an area of the impregnated pad or card. The sheet member can be suitably formed of paper and preferably held in position and ir.

contact with the impregnated pad or card by man of a staple fio:inc.

When the sheet member is wetted by the solventbased fluid through the area of contact1 the paper becomes transparent and loses its opacity As a result thereof, the printing design on the back face shows through the paper.

Conversely as the impregnated pad or card becomes devoid of fluid, the sheet member will dry and the printing design on the back face will not show through.

A suitable printing design on the back face can be in the shape of a star together with a printing design on the front face in the form of a window, through which the star can be seen when wetted. Additional words on the front face could indicate to the user that when the star fades a replacement impregnated pad or card is required.

An additional benefit provided by printing on bcth faces of the sheet member is that a contrast is provided as the sheet member- dries which enables the user to readily drudge the degree of fading and hence the degree of dryness of the impregnated member.

The sheet member is suitably formed of paper which should not be too thick nor too thin and have a quality that will give good transparency when wetted and good opacity when dry. Although white paper can be used it has been found that the effect can be enhanced by using tinted or coloured paper.

The ink. used for the printed designs must be of a quality that will not run in the presence of solvent-based fluid.

The pad or card member together with the solventbased fluid and the indicating device are preferably supplied in a sealed arrangement. Such arrangement is suitably formed from two sheets of laminated material, preferably comprising of a laminate of polyethylene, alumnium foil and paper, with a sealing coating on top of said paper.

Firstly, the sides and bottom portions of the sheets of the 3aminate are sealed together and thus form a pouch into which a pad or card member having an indicating device in accordance with the invention attached thereto is located therein. Thereafter, a suitable quantity of solventbased fluid is metered into the pouch and the top portion of the two laminate sheet members are then heat sealed.

Such sealed arrangement, when it is desired to utilise same, can be rendered effective by removing the top portion of the laminated arrangement thereby exposing the upper portion of the impregnated pad or-card and also the indicating device of the present invention. Such arrangement will continue to give off solvent-based vapour from the exposed portion of the pad or card member until all of the solvent-based fluid has been used up. As the pad or card member begins to dry the printed design on the back face of the sheet member will apparently fade and the user then knows that a new impregnated pad or card member is required.

The present invention will be further iilustrated, by way of example, with reference to the accompanying drawing in which the sole figure is a schematic view of a sealed arrangement referred to above which is partly broken away to indicate an impregnated card member and the associated indicating device therein.

As illustrated, a sealed arrangement, generally referenced 10, comprises a laminated housing 11 formed of two sheets of laminated material sealed at the sides and top and bottom. The housing 11 contains a fibrous card member 12, solvent-based fluid 13 (impregnating the card) and an indicating device 14 in accordance with the present invention.

Such indicating device 14 is formed from a sheet of paper and has printing in the form of a star 16 on the underside thereof. A window 15 is suitably marked on the front face of the paper, to clearly locate the position of the star, together with wording 17 in the form of an instruction to the user.

The sealed container 10 when located in its desired environment has its top portion removed and the fibrous card member 12 then allows solvent-based fluid vapour to pass into the environment. By being soaked with fluid, the indicating device 14 has become transparent and the printed design 16 can be seen therethrough.

The user can then look at the top portion of the fibrous card member at regular intervals and when the star fades, as the paper begins to dry, the user nows it is time to replace the died card with a new impreanatea refill.

This may suitably be effected by utilising a further sealed arrangement.

It can thus be seen that the indicating device of the present invention provides a simple, yet effective, means for indicating to the user when a further charge of solvent-based fluid is required.

It is clear that the indicating device of the present invention can be varied in size as required and the printing can be of any desired form and/or colour.

Claims (15)

1. An indicating device for indicating when a pad or card impregnated with solvent-based material requires replacing, said device comprising a sheet member having printing thereon on at least one face, namely the back face, and such face being in contact with an area of the impregnated pad or card.

2. An indicating device as claimed in claim 1, in which the sheet member is formed of paper.

3. An indicating device as claimed in claim 2, in which the paper is tinted or coloured.

4. An indicating device as claimed in claim 1, 2 or 3, in which the sheet member is held in position and in contact with the impregnated pad or card by means of a staple fixing.

5. An indicating device as claimed in any preceding claim, in which the sheet member when wetted with the solvent-based material becomes transparent, enabling the printing on the back face to be seen through the front face.

6. An indicating device as claimed in claim 5, in which additional printing on the front face is utilised in conjunction with the printing on the back face.

7. An indicating device as claimed in any preceding claim, in which a printing design on the back face is in the shape of a star together with a printing design on the front face in the form of a window, through which the star can be seen when wetted.

8. An indicating device as claimed in claim 7, in which additional wordage is provided on the front face to indicate to the user that when the star fades a replacement impregnated pad or card is required.

9. An apparatus for providing a solvent-based atmosphere within a closed housing, said apparatus comprising a pad or card member together with a solvent-based fluid and an indicating device in accordance with any preceding claim.

10. An apparatus as claimed in claim 9, in which the apparatus is supplied in the form of a sealed arrangement.

11. An apparatus as claimed in claim 10, in which the sealed arrangement is formed from two sheets of laminated material.

12. An apparatus as claimed in claim 11, in which the laminated material comprises a laminate of polyethylene, aluminium foil and paper, with a sealing coating on top of said paper.

13. An apparatus as claimed in claim 9, 10, 11 or 12 in which in use a portion of the upper part of the laminated material is removed to expose a suitable area of the impregnated pad or card member together with the indicating device which will indicate when all or substantially all of the solvent -based material has evaporated.

14. A process for preparing an apparatus as claimed in claim 11 or 12 in which, firstly, the sides and bottom portions of the sheets of the laminate are sealed together to form a pouch, locating in said pouch a pad or card member having an indicating device as claimed in any one of claims 1 to 6 attached thereto, metering a suitable quantity of solvent-based fluid into said pouch, and thereafter heat sealing the top portion of the two laminate sheet members.

15. An apparatus as claimed in any one of claims 9 to 13, substantially as hereinbefore described with reference to the accompanying drawings.