GB2075865A - Water jetting nozzle - Google Patents

Abstract

In order to avoid the need for highly accurate machining of the outlet bore of a water jetting nozzle for use in producing a high velocity water jet, the nozzle outlet is formed by a through bore 8 in an insert 7 mounted in the nozzle body 2 and formed from sintered glass. The insert is formed by packing an annular die recess with powdered glass, closing the recess by means of a punch to form a lightly bonded solid, which is ejected and heated to a temperature appropriate to sinter the glass. The manufacture of the insert in this way makes it possible to have outlet bores of non-cylindrical cross section. <IMAGE>

Description

SPECIFICATION Water jetting nozzles The present invention relates to water jetting nozzles and to a method of their manufacture.

Water jetting apparatus is well known for cleaning and other purposes which produces a jet of water at very high velocity, often near sonic speed. The outlet nozzle of such water jetting apparatus normally comprises a cylindrical body having a large diameter inlet bore at one end and a finer diameter outlet bore at the other. These nozzles have, in the past, been very expensive to produce because of the need for extreme accuracy in the production of the inlet and outlet bores.

The present invention seeks to provide a water jetting nozzle which can be manufactured more cheaply than the prior water jetting nozzles and achieves this aim by providing the nozzle with an annular insert which has a through passageway which defines the outlet of the nozzle, the insert being formed from a sintered powdered material such as glass.

Thus according to the present invention there is provided a water jetting nozzle comprising a holder and an annular insert mounted in the holder and having a through-passageway defining the outlet of the nozzle, the insert being formed from a sintered powdered material. Preferably the material is glass.

Suitably the holder is a cylindrical body having an inlet end and an outlet end and, at its outlet end, a radially inwardly extending end wall having an outlet aperture therethrough of cross sectional dimensions greater than those of the passageway of the insert, the insert being mounted in the body adjacent the end wall. The insert may be secured in position by adhesive.

By making the through passageway cylindrical, a cylindrical water jet is obtained in use. Sometimes, however, it is desirable to have a jet of other cross sectional shapes such as that of a flattened rectangle and while this was not practicable with the prior art nozzles, it can be achieved in the present invention by providing an insert with a through passageway of appropriate cross-sectional shape. Because the through passageway is shaped during the sintering of the material of the insert, there is no need for drilling of the insert or other, complicated cutting procedures to obtain non-cylindrical passageway cross-sections.

A second aspect of the invention provides a method of making a water jetting nozzle comprising fitting to a holder an annular insert having a through-passageway for defining the outlet of the nozzle, the insert being formed from a sintered powdered material. The insert may be formed by filling the material, such as glass, into a die recess of a shape corresponding to the desired shape of the insert, compressing the material to form a lightly bonded solid, ejecting the solid and heating it to a temperature appropriate to sinner the material. After cooling, the insert may then be fitted to the holder.

The invention will be further described with reference to the accompanying drawings in which Figure 1 is a longitudinal sectional view of one embodiment of the present invention; Figure 2 is a perspective view, partly cut away, of part of a second embodiment of the present invention; and Figure 3(aJ to (c) are three sectional views showing the method of manufacture of an insert for use in an embodiment similar to that of Figure 1.

The water jetting nozzle 1 shown in Figure 1 comprises a generally cylindrical stainless steel body portion 2 through which is drilled a bore 3 from the upper, inlet end of the nozzle to a location just above the lower, outlet end. At the outlet end the nozzle 1 has an annular radially inwardly directed end wall 5 of approximately the same thickness longitudinally of the nozzle as the peripheral wall of the nozzle body and is pierced by a drilled, coaxial cylindrical through-bore 6.

Disposed within the body portion 2 is a cylindrical, annular insert formed from sintered powdered material such as glass and which has a coaxial cylindrical through-bore 8 which defines the outlet of the nozzle. The insert 7 is suitably dimensioned and positioned so that it abuts the end wall 8 and the inner peripheral surface of the cylindrical body portion 2 and is secured in position with adhesive.

The cross-sectional dimension, i.e. the radius of the bone 8 is smaller than that of the bone 6 so that it is the bone 8 which defines the outlet of the nozzle.

The body 2 is provided with an annular rib 9 used to secure the nozzle to the water jetting apparatus; alternatively a threaded engagement may be used.

In use, the inlet end of one or more of the illustrated nozzles is connected to a per se known water jetting apparatus (not shown) which provides water under very high pressure so that a fine cylindrical jet of water exits from the outlet bore 8 in the insert 7 at near sonic speed. This jet may be used for the cleaning and various other purposes which are well known applications of water jetting apparatus.

The embodiment of Figure 1 produces a cylindrical jet of water. Sometimes it is desirable to have a jet of a different cross-section, e.g. a flattened rectangular or hexagonal cross-section. Figure 2 shows part of an embodiment which produces a jet of flattened cross-section. In the embodiment of Figure 2 the end wall 5' is pierced by a diametrally extending rectangular slot 10 and the insert 7', again formed from centred powdered glass has a through bore 8' of rectangular or flattened-hexagonal cross section, the dimensions of th rough bore decreasing towards its outlet end. In use this produces a jet of strip-like cross section.

Figure 3 a, b and c illustrate how an insert may be made for an embodiment of water jetting nozzles similar to that of Figure 1. Here a die 20 made of suitable material with a through bore which defines the outside diameter of the insert has a fixed centre pin 21 which defines the through bore of the finished insert. The annular space between 20 and 21 is filled with powdered glass which is compressed between a lower punch 22 and an upper punch 23. This compressing is sufficient to form a iight bonding of powder, which is then ejected as a solid. When sufficient inserts have been formed they arethen batch loaded into a sintering oven, for an appropriate time and then removed.

When the sintered inserts have cooled they may be fitted in an appropriate nozzle body portion 2. It will be appreciated that inserts having through bores of other cross sectional shapes such as the one shown in Figure 2.

In Figure 3a the lower punch 22 is shown in its lowest position, this position being adjustable to enable variations of the insert length to be made; Upper punch 23 is shown it is highest position. The powdered glass may be introduced with the punches in this position. As shown in Figure 3b, the upper punch 23 is then lowered to compress the powdered glass.

Figure 3a illustrates the upper and lower punches 23 and 22 raised to eject the insert. The ejected insert is automatically moved to one side when thefiller (not shown) is moved to fill the annular cavity during its next cycle of operations.

Claims (13)

1. Awaterjetting nozzle comprising a holder and an annular insert mounted in the holder and having a through-passageway defining the outlet of the nozzle, the insert being formed from a sintered powdered material.

2. A nozzle according to Claim 1 wherein the material is glass.

3. Anozzle according to Claim 1 or 2 wherein the holder is a cylindrical body having an inlet end and an outlet end and, at its outlet end, a radially inwardly extending end wall having an outlet aperture therethrough of cross sectional dimensions greaterthan those of the passageway of the insert, the insert being mounted in the body adjacent the end wall.

4. A nozzle according to Claim 1,2 or 3 wherein the passageway is cylindrical.

5. A nozzle according to Claim 1, 2 or3 wherein the passageway is shaped to produce a jet of a flattened cross section.

6. A nozzle according to Claims 3 and 5 wherein the outlet aperture is formed by a slot extending across the outlet end face of the body.

7. A method of making a waterjetting nozzle comprising fitting to a holder an annular insert having a through passageway for defining the outlet of the nozzle, the insert being formed from a sintered powdered material.

8. A method according to Claim 7 wherein said material is glass.

9. A method according to Claims 7 or8 and including the step of turning the inset by filling the material into a die recess of a shape corresponding to the desired shape of the insert, compressing the material to form a lightly bonded solid, ejecting the solid and heating itto a temperature appropriate to sinterthe material.

10. Awaterjetting nozzle constructed and arranged substantiaily as hereinbefore described with reference to and as illustrated in Figure 1or Figure 2 of the accompanying drawings.

11. A method of making a water jetting nozzle substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.

12. A nozzle made by the method of anyone of Claims 7 to 9 and 11.

13. Water jetting apparatus having at least one waterjetting nozzle according to anyone of Claims 1 to 7, 10 and 12.