GB2544056A - Blocking chimneys for smoke testing - Google Patents

Abstract

A device generally for use in smoke testing or for work on chimneys comprising a means for blocking a chimney from underneath, together with a means for raising this means into position and a means for operating the device. The device may be inflatable or resilient. The inflatable embodiment comprises a bag 1 which is positioned in the flue and then inflated to block the chimney. The resilient or elastic embodiment comprises a flexible member which is placed in the flue and compressed between two elements (fig 8, 12) by a spring element (fig 8, 13) causing it to expand radially and seal the chimney. The arrangement preferably includes ducts (fig 3, 14) or arms (fig 9, 18) to create gaps (fig 9, 21) to allow limited passage of air past the sealing device.

Description

BLOCKING CHIMNEYS FOR SMOKE TESTING

Background.

This invention is for use in smoke pressure testing the integrity of chimneys. For this test, smoke pellets are lit at the base of the flue, the bottom of the chimney is blocked, and then when smoke appears, the top is blocked. Smoke escaping from the stack or from neighbouring pots reveals where the chimney is faulty.

The current method of blocking the chimney at the top is for a person to climb up and cover the top of the pot with for example a sandbag, football bladder, or polythene bag. This is time-consuming, the job requires two people, and can be difficult and dangerous on wet roofs and tall stacks.

This invention enables a smoke test to be completed quickly, safely and economically without requiring external access to the top of the chimney.

It also has other applications, such as preventing rubble descending when working on a chimney stack.

Statement of invention.

The invention comprises at least an inflatable or expandable or flexible means for blocking the chimney at the top, from underneath, together with a means for raising this means into position including or having separate a means for operating this first means, for example semi-rigid pipe or a trigger; and a means for withdrawing the first means from the chimney after completion of the test, which may be the aforesaid raising means or otherwise.

The blocking means may totally seal the chimney top or may be provided with one or more means for allowing the continuing passage of a restricted amount of smoke during the smoke test.

There may also be provided accessory means, for example but not exclusively a brush, to help guide the first-mentioned means upwards or for other purpose.

If the first means is inflatable, there will be available a means at the bottom of the chimney for inflating, monitoring and deflating the first means. If the first means is not inflatable, there may be a means holding it closed and a releasable means operated mechanically or by pressure or by electrical wire or electronically by wireless transmission from the ground. The device may also incorporate a means for closing the deployed means after the test has been completed.

There may also be a means for locating the bottom end of the rod or pipe assembly in a set position. This could releasably clamp onto the rod or pipe assembly, or have set locating positions to receive a fitting at the bottom end of the said assembly.

This device can be used for flues, pipes or ducts or in any situation or alignment where the far end is inaccessible or accessible with difficulty.

The invention will now be described solely by way of example and with reference to the accompanying drawings, figures 1 to 10.

Description.

Blocking the chimney at the top or within can be accomplished by means of for example an inflatable bag assembly (the Top Unit) shown in figure 1, preferably including a protective cover 2, the bag itself 1 being assembled to a stem tube 3 which is airtightly and releasably fitted onto the end of a hollow semi-rigid rod 4 which has other sections joinable together by suitable releasable connectors. This assembly is pushed up the flue, adding sections as necessary, until the Top Unit appears above the flue terminal. It is then pulled down until it is just inside the flue terminal. The inflation and monitoring unit 5 (the Base Unit) in figure 4 is connected to the bottom end of the rods 4. The bottom pipe section may if desired be shortened to keep the pipe inside the fireplace to allow it to be closed off for the test, in which case there may be attached a fitting such as an elbow or tee 8 to which the Base Unit can be connected. Shown in figure 5, there may also be a means here for adjusting the vertical position of the bottom end of the rods, by for example an upright channel 6 with locating steps 7 at fixed intervals along its length into which the elbow or tee 8 will fit.

The Base Unit 5 comprises at least a fitting with valve 9 and a pressure reading means 10, connectable to the rod assembly 4 and to a means of applying pressure or vacuum, normally but not exclusively a pump. In use, at the requisite point in the test procedure, pressure or vacuum is applied until the gauge indicates that, following a small rise and fall, a required pressure or vacuum is reached and maintained. This means that the Top Unit 1 has deployed (figure 2).

After the prescribed test, the valve is opened to release the pressure or vacuum: a pump may be used if desired, then the rod assembly is pulled down and dismantled. The Top Unit can be tested for air-tightness, and if good can be folded and secured for use again.

The Top Unit 1 may comprise a fabricated, woven, formed or moulded bag 1, with internal tensioner or tensioners if required (see patent number GB2251929), and a stem tube 3 as described above. Optionally there may be a guidance means attached such as a brush, and preferably a cover 2 to protect the bag and keep it folded. This cover will preferably remain attached to the inflated bag so that, on removal, there is nothing left behind in the flue.

This cover 2 may be of flexible sheet material preferably fixable or fixed to the bag, said cover being of fabric or film, or from thin rigid sheet which may be formed into for example flexible petal shapes. In any of these cases the cover may be secured over the bag with ties or bands or clips 11 which release the cover when pressure is applied inside the bag. Alternatively, this cover may be in two or more parts which together enclose the bag 1 and which separate on inflation to release the bag.

The bag may optionally be provided with for example a number of short tubes or other hollow ducts 14 shown in figure 3 fixed round the periphery of the bag for allowing the continuing passage of a restricted amount of smoke during the smoke test while the bag itself closes off the rest of the flue or duct. These tubes may themselves act as the cover or may instead be held inside the aforesaid cover.

Instead of a bag for the Top Unit, it may comprise for example elastomer foam which may but not necessarily be of closed-cell polymer material with or without ducts moulded-in or as above described, being expanded by inflating a membrane 15 within, as in figure 3; or it may comprise a sealed flexible barrel-shape (figure 7) or toroid (as included in figures 6 and 10) or other shape, fixed between or bonded to two rigid or semi-flexible end covers12. In these cases, expansion may be by induced air pressure or vacuum (figure 7) or by releasing a spring or springs 13 which force the end covers closer together, forming a doughnut shape between the end covers and thus sealing the chimney or resting on top of the chimney to close it as required. It may be that instead of this last-mentioned design, a cylinder or shape of closed-cell foam 17 is employed between the end covers, the spring or springs on release forcing the foam into a patty shape, shown in figure 8. The upper cover or both ends may be shaped to assist guidance when in transit up the flue. A further embodiment may be a disc of material such as film or fabric or foam with supporting structure if required which is held folded when in transit, is deployed when required, and may but not necessarily be folded again for retrieval.

The release means if required for any of the above embodiments may be by locking pin or pins 22, sear and bent, crank 23, cam, peg, dog or sprung catch as in an umbrella but may be otherwise, or other device. Release may be effected by a tug on cord or wire 24, a movement of a lever, switch or button, or by a signal. It may also be that the release means is also used to collapse or re-set the blocking means by for example but not exclusively pulling on the same cord which was used for deployment or by a separate cord 25. If cords for two purposes are used, they can be differentiated for example by colour.

In figure 8, the upper cover or cap may be attached by Iegs18 to a lower part 19 thus acting as a cage for the inflatable or expandable means. The lower cover or plate 12 is able to slide within the cage, being guided by a rod or piece inserted into the stem or in the upper cover or otherwise. If sliding in the upper cover, the sliding part 20 in figure 10 may protrude through the top and act as a signal above the chimney pot that the device has deployed. The cage forms the expandable part into a lobed shape which, while gripping the chimney, allows gaps 21 instead of the tubes 14 (figure 9).

In practice, any combination of the above may be used. If air pressure is not required for operation, the raising means may for convenience be conventional sweeps’ rods.

The device is also suitable for blocking a flue to prevent rubble descending when for example a chimney stack is being worked on.

Claims (13)

Claims.

1. A device comprising a means for blocking a chimney at the top or within, from underneath, together with a means for raising this means into position and including a means for operating this first means; and a means for withdrawing the first means which may be the aforesaid raising means or otherwise.

2. A device as claimed in claim 1 where the blocking means is inflatable or expandable by external pressure or vacuum, releasably attached to one end of sections of hollow semi-rigid rods or pipes all releasably connected airtightly together.

3. A device as claimed in claims 1 where there is also attached or separate a protective cover or sections of cover for the blocking means.

4. A device as claimed in claim 1 where there is provided or attached gaps or spaces or ducts so that the blocking means does not entirely block the chimney.

5. A device as claimed in claim 1 where there is provided or available an accessory means such as for example a brush or sensor for guidance or other purpose.

6. A device as claimed in claim 2 where there is also provided or available a means at the bottom of the chimney for deploying, monitoring and disengaging the first means.

7. A device as claimed in claims 1 and if desired in claims 3 to 5 where the blocking means is not inflatable by external means but is flexible or expandable or conformable and may include a means for holding it closed and a releasing means operated mechanically or by pressure or by electrical wire or electronically by wireless transmission from the ground.

8. In the embodiment claimed in claim 7, the raising means in claim 1 may not need to be hollow.

9. A device as claimed in claim 7 where there is also a means for closing, retracting, compressing or folding the blocking means for removal purposes and may but not necessarily include a restraining catch.

10. A device as claimed in claim 7 where there are two or more flat or shaped pieces separating the blocking means where one part slides within any other.

11 .A device as claimed in claim 10 where a part may protrude above the assembly for use as a signal that the device has deployed.

12. In any of the embodiments claimed in preceding claims, there may be a means for locating and supporting the bottom end of the raising means in fixed or set positions.

13. A device as claimed in any of the above claims for use where a tube, pipe or duct to be blocked is in any orientation.