Cleaning and liquid contact with solids – Processes – With treating fluid motion
Patent
1991-05-21
1993-08-31
Morris, Theodore
Cleaning and liquid contact with solids
Processes
With treating fluid motion
134 2211, 134 2214, 134 36, 134 42, B08B 300, B08B 902
Patent
active
052405087
DESCRIPTION:
BRIEF SUMMARY
This invention relates to apparatus for use in and a method of removing asbestos from surfaces to be stripped.
As is well known, asbestos dust is extremely dangerous to human beings and strict regulations govern the removal of asbestos from surfaces to be stripped.
Asbestos stripping takes place in sealed enclosures and normally the asbestos insulation is saturated with water or other liquid before stripping. Conventionally, in order to saturate the asbestos, the surface of the asbestos insulation is first broken open and the asbestos is then sprayed, often for several hours. Both the breaking open of the insulation and the action of the spray or liquid jet hitting the insulation creates airborne dust which could be harmful to an operative even when a respirator is worn.
According to one aspect of the invention, there is provided apparatus for use in removing asbestos, the apparatus comprising at least one hollow needle having a maximum cross-sectional dimension which is not greater than 4 mm, a closed pointed end and a peripheral wall provided with one or more apertures for discharging liquid fed to the inside of the needle into the asbestos to be removed, and means for supplying liquid under pressure to the inside of the needle.
Preferably, the or each needle is of circular cross-section and typically, the or each needle has an outside diameter of 2.5 mm or less.
Preferably, the or each needle has a plurality of apertures distributed around its periphery and, if the needle is long, also along the length of the needle.
Advantageously, the or each aperture extends outwardly through the peripheral wall of the needle in a rearwardly inclined direction to minimise the risk of becoming blocked as the needle is inserted into the asbestos.
Preferably, the apparatus comprises a plurality of needles supplied from a common source of pressurised liquid and in this case, conveniently, an individual flow control valve is associated with each needle.
According to another aspect of the invention, there is provided a method of removing asbestos from a surface to be stripped, the method comprising the steps of inserting at least one hollow needle having a closed pointed end and a maximum cross-sectional dimension of 4 mm into the asbestos, injecting liquid into the asbestos through one or more apertures in the peripheral wall of the needle, the liquid being supplied to the or each needle under pressure, and subsequently stripping the insulation from said surface.
Conveniently, the injection of liquid into the asbestos takes place as a sealed enclosure is built around the surface to be stripped.
The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic view showing one embodiment of apparatus according to the invention,
FIG. 2 is a section taken along line II--II of FIG. 1,
FIG. 3 is a perspective view of part of the apparatus of FIGS. 1 and 2,
FIG. 4 is a sectional view of one of the injection units, on an enlarged scale,
FIG. 5 is a sectional view of part of a modified needle on an even larger scale, and
FIG. 6 is a side view showing part of a further embodiment of apparatus according to the invention.
Referring to FIGS. 1 to 5 of the drawings, the apparatus shown therein comprises a plurality of injection units each comprising a hollow needle 10 and a flow control valve 11.
As best shown in FIGS. 4 and 5, each needle 10 has a closed pointed end 12 for insertion into asbestos insulation to be stripped from a surface, e.g. a pipe, and at least one, but preferably two or more apertures 13 distributed around the periphery of the needle for injecting liquid fed to the inside of the needle by the control valve 11 into the asbestos. The The pointed end 12 could be at the tip of an oblique ellipsoidal end surface 14 as shown in FIGS. 1 and 4, but alternatively the end of each needle may be swaged to a point 12 as shown in FIG. 5. The apertures 13 are preferably slanted away from the pointed end 1
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patent: 4264993 (1981-05-01), Freeman et al.
patent: 4626291 (1986-12-01), Natale
patent: 4803771 (1989-02-01), Lyons
patent: 4872920 (1989-10-01), Flynn et al.
patent: 4908068 (1990-03-01), Pittman et al.
Chaudhry Saeed T.
Morris Theodore
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