GB2158749A

GB2158749A - Abrasive blasting nozzle

Info

Publication number: GB2158749A
Application number: GB08412624A
Authority: GB
Inventors: John Link
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-05-17
Filing date: 1984-05-17
Publication date: 1985-11-20
Also published as: GB8412624D0

Abstract

A blasting nozzle having high-pressure water inlets (11,12) an inlet (15) for abrasive laden water, a barrel (10) to which said inlets lead and an outlet from the barrel, the inlets opening into the barrel in such a way that, in use, while entraining an accelerating the abrasive, the high pressure water forms a curtain to protect the barrel walls from the abrasive action. The jet(s) of high pressure water may comprise two fan-shaped jets, or a single divergent conical jet with the barrel (10). <IMAGE>

Description

SPECIFICATION Blasting nozzle The present invention relates to a blasting nozzle.

The nozzle of the invention is useful in cleaning apparatus employing abrasive laden jets of water.

The use of abrasive laden jets is common in cleaning such items as the legs of oil rigs, but such situations create special difficulties because the cleaning is actually performed by a driver who may in some way below the sea water surface.

Problems arise in connection with the supply of abrasive from the surface to the point of operation.

It is generally not practical simply to supply the abrasive laden water at high pressure down a pipe because there will be a considerable pressure drop and there will be rapid wear on the pipe. Accordingly, a common procedure is to supply a water laden abrasive at relatively low pressure down one conduit or flexible pipe and to supply water at high pressure down a second conduit or flexible pipe, these two supplies meeting at a nozzle which has an inlet connected to each supply and an outlet through which the abrasive laden jet passes. The high pressure water is dispersed within the nozzle in a diverging jet and this creates a vacuum producing action in the inside of the nozzle which entrains and accelerates the abrasive containing water which is supplied to the interior of the nozzle at low pressure.A nozzle assembly of this type is shown, for instance, in Figure 2 of US Patent 3 994 097.

The aim of this invention is to provide a nozzle which is more resistant to wear than previously employed nozzles.

According to the present invention, there is provided a blasting nozzle having a high pressure water inlet, an inlet for abrasive laden water, a barrel to which said inlets leads and an outlet from the barrel, the inlets opening into the barrel in such a way that, in use, while entraining and accelerating the abrasive, the high pressure water protects the barrel walls from the abrasive action.

In prior nozzles the high pressure water jet accelerates the abrasive laden water which then strikes the internal wall of the barrel and causes rapid wear. With the present invention, while the abrasive containing slurry is entrained and accelerated it is generally separated from the lower walls by a wall or curtain of water.

This is preferably brought about by having one or more high pressure water inlets to the barrel of the nozzle which surround or bound an inlet for the abrasive laden water. The high pressure water supply could, for instance, be in the form of two fan jets with their planes parallel with the inlet for the abrasive laden water to the barrel being between them. The barrel should be of such a length that it can appropriately accelerate the slurry but it is not so long that the slurry will penetrate through these walls or curtains of water.Other forms of high pressure water jets are envisaged such as conical or circular or a number of jets which are either flat or curved or which are generally fan shaped and which provide an enclosure for the abrasive laden supply.

In order that the invention may be more clearly understood, the following description is given by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic side view of a nozzle according to the invention, Figure 2 is a section on the line ll-ll of Figure 1, Figures 3 and 4 are sections similar to Figure 2 of alternative embodiments.

As shown in Figures 1 and 2, very schematically, the nozzle of the invention has a barrel 10 with inlets 11 and 12 to it, each supplying, in use, a high pressure fan shaped jet of water. These inlets are supplied from a single conduit 13 for high pressure water. Located between the inlets 11 and 12 is an inlet 14 for an abrasive laden water supply at relatively low pressure. This is connected to a conduit 15 for the supply of such water.

The two fan shaped high pressure water jets have the effect of accelerating the abrasive laden water supply from the inlet 14 to the barrel 10.

However, they are designed to provide a wall or curtain of water between the abrasive and the walls of the barrel such that, even with prolonged use, the barrel suffers relatively little wear.

Figure 3 shows an alternative embodiment whereby a diverging conical high pressure water jet from an annular orifice 30 surrounds a supply from an orifice 31 of abrasive laden water. In the Figure 4 embodiment, in place of the circular orifice 30 of Figure 3, there are three arcuate orifices 40 surrounding an orifice 41 for the abrasive laden water.

Obviously many variations can be made within the principle of providing protection for the interior of the nozzle using the water which accelerates the abrasive.

The invention is particularly appropriate for use with my British Patent 2 057 879 which effectively provides without interruption an appropriate abrasive water mixture of relatively constant abrasive content.

This invention can be combined, if desired, with one or both of the inventions of my co-pending applications of even date herewith.

1. A blasting nozzle having a high-pressure water inlet, an inlet for abrasive laden water, a barrel to which said inlets lead and outlet from the barrel, the inlets opening into the barrel in such a way that, in use, while entraining an accelerating the abrasive, the high pressure water protects the barrel walls from the abrasive action.

2. A nozzle according to claim 1 wherein there are two nozzles at the upstream end of the barrel for high pressure water, each delivering a fan shaped jet in use and having between them an inlet for abrasive laden water to be accelerated.

3. A nozzle according to claim 1 wherein there is an annular orifice at the upstream end of the barrel to supply a diverging conical high pressure

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Blasting nozzle The present invention relates to a blasting nozzle. The nozzle of the invention is useful in cleaning apparatus employing abrasive laden jets of water. The use of abrasive laden jets is common in cleaning such items as the legs of oil rigs, but such situations create special difficulties because the cleaning is actually performed by a driver who may in some way below the sea water surface. Problems arise in connection with the supply of abrasive from the surface to the point of operation. It is generally not practical simply to supply the abrasive laden water at high pressure down a pipe because there will be a considerable pressure drop and there will be rapid wear on the pipe. Accordingly, a common procedure is to supply a water laden abrasive at relatively low pressure down one conduit or flexible pipe and to supply water at high pressure down a second conduit or flexible pipe, these two supplies meeting at a nozzle which has an inlet connected to each supply and an outlet through which the abrasive laden jet passes. The high pressure water is dispersed within the nozzle in a diverging jet and this creates a vacuum producing action in the inside of the nozzle which entrains and accelerates the abrasive containing water which is supplied to the interior of the nozzle at low pressure.A nozzle assembly of this type is shown, for instance, in Figure 2 of US Patent 3 994 097. The aim of this invention is to provide a nozzle which is more resistant to wear than previously employed nozzles. According to the present invention, there is provided a blasting nozzle having a high pressure water inlet, an inlet for abrasive laden water, a barrel to which said inlets leads and an outlet from the barrel, the inlets opening into the barrel in such a way that, in use, while entraining and accelerating the abrasive, the high pressure water protects the barrel walls from the abrasive action. In prior nozzles the high pressure water jet accelerates the abrasive laden water which then strikes the internal wall of the barrel and causes rapid wear. With the present invention, while the abrasive containing slurry is entrained and accelerated it is generally separated from the lower walls by a wall or curtain of water. This is preferably brought about by having one or more high pressure water inlets to the barrel of the nozzle which surround or bound an inlet for the abrasive laden water. The high pressure water supply could, for instance, be in the form of two fan jets with their planes parallel with the inlet for the abrasive laden water to the barrel being between them. The barrel should be of such a length that it can appropriately accelerate the slurry but it is not so long that the slurry will penetrate through these walls or curtains of water.Other forms of high pressure water jets are envisaged such as conical or circular or a number of jets which are either flat or curved or which are generally fan shaped and which provide an enclosure for the abrasive laden supply. In order that the invention may be more clearly understood, the following description is given by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic side view of a nozzle according to the invention, Figure 2 is a section on the line ll-ll of Figure 1, Figures 3 and 4 are sections similar to Figure 2 of alternative embodiments. As shown in Figures 1 and 2, very schematically, the nozzle of the invention has a barrel 10 with inlets 11 and 12 to it, each supplying, in use, a high pressure fan shaped jet of water. These inlets are supplied from a single conduit 13 for high pressure water. Located between the inlets 11 and 12 is an inlet 14 for an abrasive laden water supply at relatively low pressure. This is connected to a conduit 15 for the supply of such water. The two fan shaped high pressure water jets have the effect of accelerating the abrasive laden water supply from the inlet 14 to the barrel 10. However, they are designed to provide a wall or curtain of water between the abrasive and the walls of the barrel such that, even with prolonged use, the barrel suffers relatively little wear. Figure 3 shows an alternative embodiment whereby a diverging conical high pressure water jet from an annular orifice 30 surrounds a supply from an orifice 31 of abrasive laden water. In the Figure 4 embodiment, in place of the circular orifice 30 of Figure 3, there are three arcuate orifices 40 surrounding an orifice 41 for the abrasive laden water. Obviously many variations can be made within the principle of providing protection for the interior of the nozzle using the water which accelerates the abrasive. The invention is particularly appropriate for use with my British Patent 2 057 879 which effectively provides without interruption an appropriate abrasive water mixture of relatively constant abrasive content. This invention can be combined, if desired, with one or both of the inventions of my co-pending applications of even date herewith. CLAIMS

3. A nozzle according to claim 1 wherein there is an annular orifice at the upstream end of the barrel to supply a diverging conical high pressure water jet with an inlet for abrasive laden water within that orifice.

4. A blasting nozzle constructed and arranged as hereinbefore described with reference to and illustrated in the accompanying drawings.