GB2158748A

GB2158748A - Abrasive blasting nozzle

Info

Publication number: GB2158748A
Application number: GB08412623A
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: GB8412623D0

Abstract

A blasting nozzle having a first inlet or inlets (11) for an abrasive laden water supply and a second inlet or inlets (10) for high pressure water and two working outlets (15), the axes of the two working outlets being inclined to each other. A reaction nozzle (16) may be provided to balance the reaction forces produced by the outlets (15). <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 diver who may be 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 condiut or flexible pipe, these two supplies meetint at a nozzle or 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 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.

An aim of the present invention is to provide an improved blasting nozzle.

According to the present invention, there is provided a blasting nozzle having a first inlet or inlets for an abrasive laden water supply and a second inlet or inlets for high pressure water and two working outlets, the axes of the two working outlets being inclined to each other.

With the invention, two abrasive laden water jets can be employed simultaneously on a surface to be cleaned. Moreover, the operator can readily apply the jets at an inclination to the surface to be cleaned, which provides more efficient cleaning.

For instance, in removing rust and marine growth, the previous tendency to apply the jet perpendicular to the surface involved cutting right through the rust or growth. With this invention, less energy is involved because the matter to be removed can be in effect prized off the surface. Also, the jets when applined in an inclined manner give rise to less risk of damage to the surface.

In prior constructions, it is usually necessary to have a reverse flow from the nozzle in order to balance the operator and allow him to keep his station. When, as with the present invention, there are two inclined jets, the overall effect tending to propel the operator backwards is reduced so that any reaction jet can also be reduced and this represents a saving of energy.

Preferably, the axes of the outlets are in the same plane so that no net torque is produced.

The angle between the two working outlets is preferably from 50 to 1200, most preferably around 70". It will be appreciated that the bigger this angle the less the reaction force required to assist the operator to maintain his position.

Accordingly, the advantages of the invention are that work can be conducted faster, more efficiently, with less risk of removing metal or damaging the surface being treated and with greater stability for the operator.

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: Figures 1 and 2 show schematically alternative constructions of nozzle according to the invention.

As schematically shown in Figure 1, the nozzle of the invention has a first inlet 10, for high pressure water supply, and a second inlet 11 for the supply of a low pressure abrasive/water mixture. A high pressure water supply, received through inlet 10 is split into two channels 12 which are inclined at about 70" to each other. In each of the channels 12, the water is led to a reduced orifice 13 and it leaves the orifice in a diverging, vacuum creating spray which is aimed at a converging part 14 downstream of the reduced orifice. Between the reduced orifice 13 and the converging part 14 is an inclined connection from the inlet 11 for the abrasive water medium. This, therefore is supplied into the high pressure water supply and is accelerated thereby, so as to leave through the two outlets 15 at high pressure.There is a reaction nozzle at 16, shown schematically, which is designed for providing a balance against the effect tending to push the diver away from his work station.

In the embodiment of Figure 1 where both the high pressure water and abrasive/water supplies are split prior to being joined with each other it would be possible to align the abrasive water supply with the outlet 15 instead of aligning the high pressure water supply with that outlet. In other words, in general terms it would be possible to supply the high pressure water to the inlet 11 and the abrasive laden water through the inlet 10.

Figure 2 shows an alternative embodiment where there is an inlet 20 for high pressure water and an inlet 21 for the abrasive laden water at lower pressure. A similar reaction nozzle is shown at 22. In this case the mixing between the two supplies occurs upstream of the division leading to the two outlets which are shown at 25. In like manner to the above, the high pressure water is passed through a reduced orifice 23, then it is joined by the supply from inlet 1 which is accelerated by the high pressure water in its diverging form passing to the converging prt of the nozzle shown at 24.

The division occurs downstream of that. Again, it will be possible to supply the high pressure water through an inlet such as 21 which is inclined to the general axis of the apparatus and to provide the abrasive laden low pressure water through an inlet 20 on the axis of the apparatus.

Nozzle of this type may be used with advantage in connection with the apparatus shown in my British Patent 2 075 879 which effectively provides without interruption an appropriate abrasive water mixture of relatively constant abrasive content.

Instead of having a single outlet for each of the high pressure and abrasive laden water supplies the apparatus of the invention could be provided with respective inlets for each of those supplies for each outlet. Thus, there could be up to four supply pipes to the nozzle and the nozzle could have four inlets which would eliminate the need to split either of the supplies at the nozzle. Thus the invention does embrace constructions which comprise two nozzles similar to those already known connected together with their outlets inclined to each other and with preferably a suitable reaction nozzle.

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

Claims

1. A blasting nozzle having a first inlet or inlets for an abrasive laden water supply and a second inlet or inlets for high pressure water and two working outlets, the axes of the two working outlets being inclined to each other.

2. A nozzle according to claim 1 having a reaction outlet so that the nozzle is substantially balanced.

3. A nozzle according to claim 2 wherein the axis of the reaction outlet bisects the angle between the two working outlets.

4. A nozzle according to claim 1, 2 or 3 wherein the angle between the two working outlets is from 50 to 1200.

5. A nozzle according to claim 4 wherein the angle is 70".

6. A blasting nozzle constructed and arranged substantially as hereinbefore described with reference to and as illustrated in Figure 1 or Figure 2 of the accompanying drawings.