GB2177963A - Improvements in or relating to protective apparatus used in the handling of harmful substances - Google Patents

Abstract

In a method for the removal of harmful material 28 from an object 26, eg asbestos lagging from a pipe the object 26 is surrounded by an enclosure 10, the harmful material 28 is removed from the object and deposited within the enclosure 10, foam is introduced into the enclosure to cover the removed material, and the enclosure is removed from about the object. <IMAGE>

Description

1 A 10 GB 2 177 963 A 1

SPECIFICATION

Improvements in or relating to protective apparatus used in the handling of harmful substances In recent years, realisation of the danger to health posed by harmful materials, for example, asbestos, has made it desirable to remove such materials from sites where they have been used. In the past, asbestos has been widely used for lagging pipes. The removal of lagging which is frequently old produces a greatquantity of asbestos fibres, commonly referred to as dust, and constitutes a particular hazard to persons involved in the operation, or in the vicinity.

In British Patent No. 1567260, there were proposed a method and apparatus for stripping lagging from a 10 length of pipe, in which the length of pipe and the removed material were substantially isolated from the operator and from the surroundings. In operation of the previous method, there was a tendencyfordust particles to remain suspended in the airfor prolonged periods and, whereas the bulk of the material could be safely removed using the method, small proportion of the dust remained suspended in air. Because the inhalation of small airborne particles poses a substantial threatto health, there remains a need to improve the procedure to reduce the incidence of airborne particles.

According to one aspect of the invention, a method of removing material from an object comprisesthe steps of surrounding the object with an enclosure, sealing the object in the enclosure, removing the material from the object and depositing the material within the enclosure, introducing a foam into the enclosure to coverthe removed material and removing the enclosure from aboutthe object.

The object is sealed with in the enclosure in order to prevent the stripped material, or dust theref rom, escaping from the enclosure, and accordingly any form of closure which achieves this object maybe used to seal the object within the enclosure. The material to be stripped from the object maybe inside the object, on its surface, or both.

In another aspect, the present invention relates to improvements in the method and apparatus described in 25 British Patent No. 1567260, which afford increased protection forthe operator or other persons in the vicinity from dust produced in the removal of lagging from a length of pipe, comprising the injection of foam into the apparatus before removal of the apparatus from the length of pipe. The injection of foam serves the dual purposes of reducing the dust content of the atmosphere within the apparatus, and of eliminating theform ation of further dust from the removed material. Foam has better properties in this respectthan water. 30 Thus, in a preferred foam of the present invention, a method ofstripping lagging from a length of pipe comprises a first step of placing aboutthe length of pipe the upper end portion of a bag, preferably of plastics sheet material, which is transparent in at least the regions adjacentto the pipe, the bag enclosing said length, the said bag having apertures or sleeve portions through which the operator may insert his hands intothe space within the bag, the bag further having a foam inlet, preferably at a point which in use will be abovethe 35 maximum surface level of the stripped lagging, and substantially sealing the bag with respectto the ends of said length, a second step of stripping the lagging from the pipe, the stripped lagging failing into the bottom of the bag, and a third step of injecting foam into the bag through the foam inlet onto the stripped lagging.

Preferably, the above-mentioned sleeve portions may terminate in gloves or mittens. The sleeve portions may, however, be open sleeves, in which case the operator using the apparatus would normally wear gloves 40 or gauntlets. Similarly, an operator using a bag having apertures instead of sleeve portions would normally wear gloves or gauntlets.

According to a f u rther aspect of the invention, a protective apparatus for the stripping of lagging from a length of pipe comprises a bag having one end closed and its other end capable of being detachably secured about a length of lagged pipe, forming a seal with opposite ends of the said length, the said bag being made 45 from plastics sheet material which is transparent in at least the regions thereof to be adjacentto the pipe and having apertures or sleeve portions through which an operator may insert his hands into the interior of the bag for work on the pipe, a foam inlet through which foam maybe injected into the bag, and furthercompris ing means for supplying or producing foam.

It will of course be appreciated thatthe foam inlet is preferably at a point which is above the maximum surface level of the stripped lagging that is in the upper portin of the bag.

Preferably the foam used in the invention is of a type formulated from at least one highly foaming anionic hydrocarbon surfactant, at least one solvent and at least one foam stabiliser, although in principle anyf lexible foam maybe used, for example a mechanically or chemically produced foam of the type used in fire fighting.

Afoam typical of the type preferred for use in the invention has the following properties:

pH at 200C 7 specific gravity at 200C 1.0 cloud point - u2oC freezing point -6.50C 60 minimum usetemperature -50C viscosity at 20'C 7cs viscosity at O'C 15cs flash point (Pensky-Martens-closed cup) 93'C maximum continuous storage 400C 65 2 GB 2 177 963 A temperature effect of freezelthaw: no performance loss.

An Example of a foam suitable for use in the invention is EXTOL.

The foam inlet is preferably capable of con nexion to a foam supply.

The injection of foam into the apparatus may, if desired, be controlled by a valve, tap, or other means incorporated into the foam inlet.

Ina preferred foam of the invention the bag has means for securing the front and back wal Is of the bag together at a location between the sleeve portions and the end of the bag where the removed lagging is kept.

In using the apparatus, the operator positions the bag about the object and strips off the material to be removed. When this has been done the operator opens the foam inlet to a I low foam to be injected into the bag. When the required quantity of foam has entered, the operator shuts the foam inlet and removes the bag from the pipe.

The invention wil I now be described, byway of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a front view of a protective apparatus according to the invention, and Figure2 shows a cross-sectional view of the apparatus, on the line 11-11 of Figure 1.

Referring to the drawings, the protective apparatus 10 is made from transparent plastics sheet material and all its seams are welded. The apparatus is in the form of a bag with front and back walls 12,14, the lower portion 20 of the bag acting as a receptacle forthe stripped material. In its upper portion, the bag has front and 20 back flaps 22,24which, in use, are placed about a length of a pipe 26 from which lagging 28 is to be removed. The edges of the flaps 22,24 meet when the flaps are so placed about the pipe, and they have formed integrally with them or welded to them the components of a sliding clasp fastener 30, operated by clasp 32, to form a sea I between the two flaps. The flaps 22, 24 have lateral extensions 34,36 beyond the bag to cover adjoining lengths of the lagged pipe, thus forming a seal with opposite ends of the first-mentioned length.

Two sleeve portions 38,40 are secured to the frontwall 12 of the bag, in its upper portion, at apertures42, 44, and extend into the interior of the bag. The two sleeve portions 38,40 terminate in respective mitten portions 46,48, with respective elasticated cuffs 50, 52, to grip the operator's wrists. Afurther, smaller aperture 54 is provided in the front wall 12 between the two apertures 42,44. A short, open-ended sleeve 56 extends into the bag from the aperture 54, and is provided with a tap 59 which maybe used to control the injection of foam into the bag.

Two strips 60,62 of a Velcro (Trade Mark) fastener are secured to the innerfaces of the front and backwalls 12,14, respectively, belowthe apertures 42,44, in orderthat the lower portion 20 of the bag can be sealed when the lagging 28 has been removed f rom the pipe 26.

When the protective apparatus is to be used, with the clasp fastener 30 unfastened, the two flaps 22,24 are 35 placed around the length of lagged pipe 26 and are then fastened together by sliding the clasp 32. Theflap extensions 34,36 may be secured about the pipe by string or faces 76,78 or other convenient means. The operatorthen inserts his hands and arms into the mitten and sleeve portions 46,38 and 48,40 and works on the lagging, using handtools as necessary. With the Velcro fastener 60,62 unfastened, the displaced lagging falls into the lower portion 28 of the bag, which may if necessary be supported on a table or other f latsurface 40 or in the angle of a V-shaped supporting surface. When the length of pipe has been stripped of lagging, or even during the actual stripping operation, the operator may introducefoam from a foam supplythrough the apparatus 54 and the sleeve 56to damp down dustwithin the bag, the introduction of foam being controlled bythe tap 59. When the particular length of pipe has been stripped,thetwo Velcro strips 60,62 are pressed togetherto seal the lagging spoil in the lower portion 20 of the bag. The bag maythen be removed fromthe 45 pipe by unfastening the clasp fastener30, and may be placed bodily within an outer bag fordisposal in accorclancewith existing regulations.

[twill of course be understood that the foam to be used in accorclancewith the invention will beafoam which will remain stablefora length oftimewhich issufficieritto allowsafe removal and disposal ofthe apparatus and the stripped material contained therein.

The removal of lagging carried out as described herein reduces the exposure of the operatorto harmful dust and hence increases the safety of these operations.

2

Claims (13)

1. A method of removing material from an object, comprising the steps of surrounding the object with an enclosure, sealing the object within the enclosure, removing the material from the object and depositing the material within the enclosure, introducing a foam into the enclosureto coverthe removed material and removing the enclosure from the object.

2. A method of removing material from an object as claimed in claim 1, wherein the object is a length of 60 pipe and wherein the enclosure comprises a bag, the upper end portion of the bag being placed about and so enclosing the length of pipe, and said upper end portion of the bag being transparent in at least the regions thereof to be adjacentto the pipe, the bag having apertures or sleeve portions through which the operator may insert his hands into the space within the bag, the bag further having a foam inlet at a point which in use will be above the maximum surface level of the stripped lagging, the bag being substantially sealed with c i 3 # 10 v GB 2 177 963 A 3 respect to the ends of the said length, the material being stripped from the pipe, the stripped m ateria If a] I ing into the bottom of the bag and foam being injected into the bag through the foam inlet onto the stripped lagging.

3. A method of removing material from an object as claimed in claim 1 or claim 2, wherein the foam is formed from am ixture of at least one highly foaming anionic hydrocarbon surfactant, at least one solvent and 5 at least one foam stabiliser.

4. A protective apparatus forthe stripping of lagging from a length of pipe, comprising a bag having one end closed and the other end capable of being detachably secured about a length of lagged pipe, forming a seal with opposite ends of the said length, the said bag being made from plastics sheet material which is transparent in at least the regions thereof to be adjacentto the pipe and having apertures or sleeve portions 10 through which an operator may insert his hands into the interior of the bag for work on the pipe, a foam inlet through which foam maybe injected into the bag, and further comprising means for supplying or producing foam.

5. A protective apparatus as claimed in claim 4, wherein the foam inlet is at a point on the upper part of the bag which is so lacated that it will be above the maximum surface level of the stripped lagging in the bag in 15 use of the apparatus.

6. A protective apparatus as claimed in claim 4 or claim 5, wherein the bag has means for securing the front and back walls of the bag together at a location between the sleeve portions and the closed end of the bag.

7. A protective apparatus as claimed in anyone of claims 4to 6, which has sleeve portions, and wherein 20 the sleeve portions terminate in gloves or mittens.

8. A protective apparatus as claimed in anyone of claims 4to 7, wherein the foam inlet has incorporated therein a control means for control of the injection of foam.

9. A protective apparatus as claimed in claim 8, wherein the control means comprises a valve ortap.

10. A kit of parts comprising (i) a protective apparatus forthe stripping of lagging from a length of pipe, 25 comprising a bag having one end closed and the other end capable of being detachably secured about a length of lagged pipe, forming a seal with opposite ends of the said length, the said bag being made from plastics sheet material which is transparent in at least the regions thereof to be adjacentto the pipe and having apertures orsleeve portions through which an operator may insert his hands into the interior of the bag for work on the pipe and a foam inletth rough which foam maybe injected into the bag and (H) meansfor 30 supplying foam to the foam inlet.

11. A method of removing material from an object, carried out substantially as described herein.

12. A protective apparatus substantially as described herein.

13. Any novel feature described herein or novel combination of hereindescribed features.

Printed for Her Majesty's Stationery Office by Croydon Printing Company (UK) Ltd, 12/86, D8817356.

Published by The Patent Office, 25 Southampton Buildings, London WC2A 1AY, from which copies may be obtained.