GB1603090A

GB1603090A - Jetting apparatus

Info

Publication number: GB1603090A
Application number: GB25306/77A
Authority: GB
Original assignee: Hughes & Co
Current assignee: Hughes & Co
Priority date: 1978-05-25
Filing date: 1978-05-25
Publication date: 1981-11-18

Description

(54) JETTING APPARATUS (71) We, F.A. HUGHES AND COM PANY LIMITED, a British Company of Blenheim Road, Longmead, Epsom, Surrey KT19 9AL, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to jetting apparatus.

Various forms of apparatus have been designed in the past to jet water or other liquids containing an abrasive element against a surface. In one particular form of apparatus, the jetting is produced by a nozzle having a housing with an axial bore through the housing, an insert placed in the housing, the insert having two annular lands which define therebetween an annular chamber surrounding an axial bore in the insert, the housing having a side inlet for pressurised fluid, e.g. water, so that this fluid can flow into the annular chamber, and a plurality of jets connecting the chamber to the downstream end of the insert, these jets being inclined with respect to one another towards the axis. The effect of this is for the water or other fluids to flow into the annular chamber through the inclined jet and thereby produce a suction effect, so that a slurry of the abrasive is drawn through the axial bore in the housing and is ejected from the nozzle through an outlet pipe.

It has been found that not entirely satisfactory mixing takes place and that the abrasive particles are not evenly distributed in the thus formed jets.

According to the present invention there is provided apparatus for use in jetting a fluid and entraining a substance therein comprising a bored housing with a side inlet for pressurised fluid, an end inlet at one end for the substance and an outlet at the other end for connection to a nozzle, the side inlet communicating with an annular chamber with jet openings leading from the chamber to the bore of the housing, the jet openings being directed towards the outlet and each being inclined to respective radial planes passing through the axis of the housing, the inclination of the jets to such planes all being in the same sense.

In use, the jets produce, in effect, a helical swirl to the fluid flowing through the housing.

It has been found that this helical swirl distributes the abrasive particles in the outflowing jet stream.

In one particular embodiment the jets while being inclined to the radial planes passing through the axis of the housing are each arranged in a further plane parallel to the axis of the housing so that the jets are in effect tangential to a cylindrical surface centred on the axis of the housing, and inclined to the axis of such a cylindrical surface. It has been found that a suitable inclination is less than 10 . In one particular embodiment it is proposed to provide four jets each inclined in the same sense at 6" to the respective plane passing through the axis of the housing.

In order that the invention may more readily be understood, the following description is given merely by way of example, reference being made to the accompanying drawing in which: Figure 1 is a side elevation namely in longitudinal cross-section of one embodiment of apparatus according to the invention; Figure 2 is an end view looking from the left of the insert of the apparatus of Figure 1; and Figure 3 and 4 are views similar to Figures 1 and 2 of a modified construction.

In Figure 1 there is illustrated a housing 10 of generally cylindrical configuration provided at the righthand end with an internal screw thread 11 and at the lefthand end a reduced internal diameter portion 12 having an internal screw thread 13.

At approximately the centre of length of the housing 10 there is provided a side port 14 into which is inserted the end of a water inlet pipe 15.

Threaded into the righthand end of the housing is a fitting 16 enabling the apparatus to be connected to a source of abrasive material in a slurry, and threaded into the thread 13 is an outlet jet pipe 17.

Mounted within the housing and retained in place by the fitting 16 is an insert 18. The insert 18 includes, at each end, an annular land 19, 20 and a main body portion 21 which, together with the land 1920 forms an annular space 22 within the housing. O-rings 23 and 24 provide a seal between the insert and the housing. An axial bore 25 within the insert 18 is axially aligned with the bore 26 in the fitting 16. Four jet holes 27, 28, 29 and 30 are bored from the front face 31 of the insert to the annular space 22. It will be noted that these four holes are bored so that they are inclined to respective radial planes passing through the axis 32 of the housing and this can be seen particularly in Figure 1 insofar as the holes 28 and 30 are concerned.

The axes of these holes are inclined approximately at 60 to the radial plane in question.

It will be noted from Figure 1 and in particular from the arrangement of the holes 27 and 29, that these holes are also in planes which are parallel to the axis of the nozzle so that they do not either converge or diverge with respect to one another towards or away from this axis.

In Figure 2 the front faces of the holes are indicated in full line; it will be seen that the holes are all on the same pitch circle diameter 33. The holes are all inclined in the same sense so that fluid passing from the chamber 22 forwardly to the front face 13 is given a clockwise circumferential twist with respect to a cylindrical surface centred on the axis 13, the jet holes thus being tangential to this cylindrical surface along a line inclined to the axis of such a cylindrical surface that is to say, the axis 32 of the housing 10.

In use the pipe 15 is supplied with water under high pressure, and the fitting 16 is connected to a source of abrasive. The water flows into the chamber 22 and leaves the chamber via the jet holes 27 to 30. It will be appreciated that the inclination of the holes 27, 28, 29, 30 in the manner described, that is to a radial plane passing through the jet holes, is such as to produce a swirling effect in the water as it leaves the apparatus via the outlet pipe 17. This swirling effect produces a regular dispersion of the abrasive in the water.

Figures 3 and 4 show a similar construction which has been modified slightly and produces improved results. In this construction the holes 27 to 30 are arranged so that the jets are tangential not to the cylindrical surface corresponding to the pitch circle diameter, but to the cylindrical surface 34 shown in Figure 4.

It will be appreciated that any number of holes could be drilled and in one particular embodiment four holes of 1.2 mm diameter were drilled inclined at 60 to a radial plane passing through the taxis 32 on a pitch circle diameter 33 of 20 mm the internal bore 25 having a diameter of 10 mm.

Although the apparatus of the present invention is designed for jetting abrasive in water it will be appreciated that it can be provided for mixing a multiplicity of different fluids.

WHAT WE CLAIM IS: 1. Apparatus for use in jetting a fluid and entraining a substance therein comprising a bored housing with a side inlet for pressurised fluid, an end inlet at one end for the substance and an outlet at the other end for connection to a nozzle, the side inlet communicating with an annular chamber with jet openings leading from the chamber to the bore of the housing, the jet openings being directed towards the outlet and each being inclined to respective radial planes passing through the axis of the housing, the inclination of the jets to such planes all being in the same sense.

2. Apparatus according to claim 1 wherein the annular chamber is defined by an insert in the housing, the insert comprising an inner cylindrical wall and annular lands at each end, the jet openings being in one of the lands.

3. Apparatus according to claim 1 or 2 wherein the jet openings are inclined at less than 10 to said planes.

4. Apparatus according to claim 3 wherein the jet openings are inclined at 60 to said planes.

5. Apparatus according to any preceding claim wherein the jet openings are in further planes parallel to the axis of the housing, so as to be tangential to a notional cylindrical surface coaxial with the housing and corresponding to the pitch circle diameter.

6. Apparatus according to any one of claims 1 to 4 wherein the jet openings are also inclined to planes parallel to the axis of the housing and passing through their mid points, and are tangential to a notional cylindrical surface coaxial with the housing and having a smaller radius than the pitch circle.

7. Apparatus for use in jetting fluid and entraining a substance therein substantially as hereinbefore described with reference to and as illustrated in Figures 1 and 2 of the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. end a reduced internal diameter portion 12 having an internal screw thread 13. At approximately the centre of length of the housing 10 there is provided a side port 14 into which is inserted the end of a water inlet pipe 15. Threaded into the righthand end of the housing is a fitting 16 enabling the apparatus to be connected to a source of abrasive material in a slurry, and threaded into the thread 13 is an outlet jet pipe 17. Mounted within the housing and retained in place by the fitting 16 is an insert 18. The insert 18 includes, at each end, an annular land 19, 20 and a main body portion 21 which, together with the land 1920 forms an annular space 22 within the housing. O-rings 23 and 24 provide a seal between the insert and the housing. An axial bore 25 within the insert 18 is axially aligned with the bore 26 in the fitting 16. Four jet holes 27, 28, 29 and 30 are bored from the front face 31 of the insert to the annular space 22. It will be noted that these four holes are bored so that they are inclined to respective radial planes passing through the axis 32 of the housing and this can be seen particularly in Figure 1 insofar as the holes 28 and 30 are concerned. The axes of these holes are inclined approximately at 60 to the radial plane in question. It will be noted from Figure 1 and in particular from the arrangement of the holes 27 and 29, that these holes are also in planes which are parallel to the axis of the nozzle so that they do not either converge or diverge with respect to one another towards or away from this axis. In Figure 2 the front faces of the holes are indicated in full line; it will be seen that the holes are all on the same pitch circle diameter 33. The holes are all inclined in the same sense so that fluid passing from the chamber 22 forwardly to the front face 13 is given a clockwise circumferential twist with respect to a cylindrical surface centred on the axis 13, the jet holes thus being tangential to this cylindrical surface along a line inclined to the axis of such a cylindrical surface that is to say, the axis 32 of the housing 10. In use the pipe 15 is supplied with water under high pressure, and the fitting 16 is connected to a source of abrasive. The water flows into the chamber 22 and leaves the chamber via the jet holes 27 to 30. It will be appreciated that the inclination of the holes 27, 28, 29, 30 in the manner described, that is to a radial plane passing through the jet holes, is such as to produce a swirling effect in the water as it leaves the apparatus via the outlet pipe 17. This swirling effect produces a regular dispersion of the abrasive in the water. Figures 3 and 4 show a similar construction which has been modified slightly and produces improved results. In this construction the holes 27 to 30 are arranged so that the jets are tangential not to the cylindrical surface corresponding to the pitch circle diameter, but to the cylindrical surface 34 shown in Figure 4. It will be appreciated that any number of holes could be drilled and in one particular embodiment four holes of 1.2 mm diameter were drilled inclined at 60 to a radial plane passing through the taxis 32 on a pitch circle diameter 33 of 20 mm the internal bore 25 having a diameter of 10 mm. Although the apparatus of the present invention is designed for jetting abrasive in water it will be appreciated that it can be provided for mixing a multiplicity of different fluids. WHAT WE CLAIM IS:

1. Apparatus for use in jetting a fluid and entraining a substance therein comprising a bored housing with a side inlet for pressurised fluid, an end inlet at one end for the substance and an outlet at the other end for connection to a nozzle, the side inlet communicating with an annular chamber with jet openings leading from the chamber to the bore of the housing, the jet openings being directed towards the outlet and each being inclined to respective radial planes passing through the axis of the housing, the inclination of the jets to such planes all being in the same sense.

8. Apparatus for use in jetting fluid and

entraining a substance therein substantially as hereinbefore described with reference to and as illustrated in Figures 3 and 4 of the accompanying drawings.

9. An insert for a housing of apparatus for jetting a fluid and entraining a substance therein, the insert comprising a cylindrical wall and annular lands at each end extending radially outwardly of the walls, jet openings being formed in one of the lands, the jet openings each being inclined to respective radial planes passing through the axis, the inclination of the jets to such planes all being in the same sense.