GB2251929A

GB2251929A - Inflatable chimney or pipe block

Info

Publication number: GB2251929A
Application number: GB9101270A
Authority: GB
Inventors: David Guy Woodman
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-01-21
Filing date: 1991-01-21
Publication date: 1992-07-22
Anticipated expiration: 2011-01-21
Also published as: GB2251929B; GB9101270D0

Abstract

A device for blocking chimneys, pipes or ducts comprises a bag 1 inflatable by a separate or attached pump or a gas canister 10 or reservoir 14, and to prevent over-inflation a relief valve 5, or blocking device 16 for the inflation valve (4) (Fig 4, not shown) is provided. The bag is inserted using a baton 2 to give remote control of inflation, and of deflation which is by opening the relief valve 8 or dump valve. The device is re-usable. Pressure in the bag is maintained by a tensioner 7 pulling the bag faces together if the bag is of a polymeric multilayer barrier film, or by the bag itself being elastic. A pressure responsive valve (12) may be used in conjunction with the pressurised canister (10) to maintain a constant pressure over a long period (Fig 2, not shown). <IMAGE>

Description

BLOCKING OF CHIMNEYS.

This invention relates to the non-permanent blocking of chimneys.

Chimneys, when not in use, are the cause of draughts which waste heat and make sitting near fireplaces uncomfortable. There are several solutions to this, such as permanently blocking the chimney; or as in Victorian castiron firebacks, providing a hinged flap to cover the throat. Many of these flaps are missing. The commonest method of trying to prevent the draught is to stuff newspapers and pieces of carpet up the chimney. It is also the least satisfactory, can cause fires if forgotten about, but at least the fire can be used when desired by removing the blocking material.

The new device here described fulfils the need for simple and mess-free chimney blocking, that is not a fire hazard, allows a modicum of air circulation, and can easily be removed and re-used.

According to the present invention there is provided an inflatable bag, a valve, and a means of preventing over-inflation. Depending on the type of material used to make the bag, there is a further provision of a means of keeping a positive pressure in the bag when inflated.

One such embodiment with variations is described below by way of example, with reference to the accompanying drawings in which: Figure 1 shows the complete device inflated but not inserted in the chimney.

Figure 2 shows a servo valve used in an alternative means of inflation.

Figure 3 shows a reservoir as an alternative means of retaining pressure following full inflation.

Figure 4 illustrates a blocking valve for preventing over-inflation.

Referring to Figure 1, the inflatable bag 1 is made as a totally sealed unit with necessary components sealed inside it. The bag material is a multilayer film, one of which is a barrier layer. The baton 2 to which the bag is airtightly attached makes an entry point 3 into the bag connecting both items together, allowing passage of gas between them.

At the other end of the baton there is a one-way valve 4 allowing air from a separate pump to be blown into the bag. When air is blown into the bag it becomes tight, and to prevent over-inflation there is provided a relief valve 5 on the baton such that when a certain pressure is exceeded it relieves the excess pressure. This prevents the bag from rupturing and prevents the application of excess pressure on the chimney breast. When it relieves pressure the valve can be made to whistle or screech to signify that the bag is fully inflated.

Because in general plastic films have little elasticity and are to some extent permeable, there is provided within the bag and attached or held to it by a fastening or bonded patch 6 an elastic strip 7 such that, when the bag is inflated this strip stretches, thus providing the elasticity that maintains a positive pressure inside the bag, which holds it in place even though the volume of air gradually reduces.

The baton itself is used to insert the uninflated bag up the chimney and hold it there while inflating it, and when inflated only the valve end is left visible.

To deflate the device the relief valve membrane 8, which is within reach at the bottom of the baton, is rolled down. This exposes the vent 9 and allows air to escape. The complete device can then be removed for re-use.

There are two further advantages to this bag: firstly, because of its shape and relative inelasticity, the corners of the chimney are not totally blocked off, allowing a small amount of ventilation which is desirable; and should a fire be lit when the bag is in place, it will quickly shrivel and drop into the hearth thus presenting no fire hazard.

There are variations on the above description that are equally applicable and are described below.

As illustrated in Figure 2, instead of the pump for inflation, a gas reservoir or canister 10 could be used, actuated by for example a ball valve (not shown) and with for example a balancing servo-valve 12 operating as follows: the tensioner 7 is attached to this spring-loaded servo-valve which is fitted between the bag 1 and the higher-pressure reservoir. The servo-mechanism thus allows gas to transfer from the higher-pressure chamber to the bag when the tensioner slackens. This restores positive pressure in the bag and retensions the tensioner.

Figure 3 shows that if the pump were retained for initial inflation, then the reservoir would only need to be small enough to compensate for permeability losses. A piston inside a tube 14 similar to the baton 2 and powered by a spring 15 would be one workable arrangement.

Figure 4 gives as an alternative to the pressure relief valve 5, a blocking piston 16 held open by a spring 17, whereby when a set pressure is reached, the external inflation valve 4 is blocked off, thus sealing the assembly. A dump button or valve 18 could then be used to exhaust gas from the bag for deflation.

An elastomeric bag could be used instead of the polymeric multi-layer film but, although the tensioning device would no longer be required, the complete device would be more expensive to produce. Both of these types would have industrial uses such as temporarily blocking pipes ducts and access holes.

Claims

CLAIMS.

1. A device for removably blocking chimneys, comprising an inflatable bag, a device for inflation, a means of preventing over-inflation, and a tensioner to create and maintain positive pressure when the bag is inflated.

2. A device as claimed in claim 1 where the device for inflation is a pump, passing air to the bag via a one-way valve.

3. A device as claimed in claim 1 where the device for inflation is a pump integral with the unit.

4. A device as claimed in claim 1 where the means of preventing overinflation is a relief valve.

5. A device as claimed in claim 1 where the means of preventing overinflation is a piston valve or other device that blocks the inflation means when the correct pressure inside is reached.

6. A device as claimed in claim 1 where the device for retaining inflation is a reservoir or higher-pressure canister.

7. A device as claimed in claim 6 where the reservoir or gas canister has enough capacity to inflate the bag and to compensate for permeability losses over the design life.

8. A device as described above retaining all the features but where the tensioner is replaced by the skin tension of the bag itself.

9. A device as described above but incorporating a dump valve to release the pressure for deflation.

10. A device for removably blocking chimneys pipes ducts and access holes substantially as described herin and with reference to figures 1 to 4.

Amendments to the claims have been filed as follows 1. A device for removably blocking chimneys, comprising an inflatable bag, a means for inflating said bag, a means for preventing over-inflation, and an internal tensioning device that creates and maintains positive gas pressure inside said bag when said bag is inflated.

2. A device-as claimed in claim 1 where the means for inflation is a separate pump, passing air to said bag via a one-way valve.

3. A device as claimed in claim 1 where the means for inflation is a pump and valve integral with the unit.

4. A device as claimed in claims 1 to 3 where the internal tensioning device for retaining inflation is replaced by a reservoir.

5. A device as claimed in claims 1 to 3 where the internal tensioning device for retaining inflation is replaced by a higher-pressure canister with servo demand valve.

6. A device as claimed in claim 5 where the gas canister has enough capacity to inflate the bag and to compensate for permeability losses over the design life.

7. Adevice as claimed in claims 1 to 6 where the means of preventing over-inflation is a relief valve.

8. A device as claimed in claims 1 to 6 where the means of preventing over-inflation is a piston valve or other device that blocks the inflation means when the correct pressure inside is reached.

9. Adevice as described in claims 1 to 8 where the means for limiting internal pressure is also used to release said pressure for deflation.

10. A device as described in claims 1 to 8 where the means for limiting internal pressure incorporates a device for release of said pressure for deflation.

11. A device as described in claims 1 to 10 where there is provided a rigid baton handgrip with some or all of the features claimed above incorporated therein.

12. A device for removably blocking chimneys pipes ducts and access holes substantially as described herein and with reference to figures 1 to 4.