Abstract
A filter for a high-pressure nozzle having a tubular section and a cap section. The cap section and/or the tubular section are provided with a plurality of filter slots which extend in the longitudinal direction of the tubular section and each have a first end situated on the side of the tubular section and a second end situated on the side of the cap section. A sleeve is arranged coaxially with the tubular section and covers the filter slots in the region of the first end of the filter slots.
Claims
1. Filter for a high-pressure nozzle having a tubular section and a cap section, wherein the cap section and/or the tubular section are provided with a plurality of filter slots, which extend in the longitudinal direction of the tubular section and each have a first end situated on the side of the tubular section and a second end situated on the side of the cap section, wherein a sleeve arranged coaxially with the tubular section is provided, said sleeve covering the filter slots in the region of the first end of the filter slots.
2. Filter according to claim 1, wherein the sleeve is arranged within the tubular section and/or the cap section and forms a flow channel through the filter, at least in some section or sections.
3. Filter according to claim 1, wherein a central bore of the sleeve is widened towards the upstream end.
4. Filter according to claim 3, wherein an end face of the sleeve is of rounded design at the upstream end.
5. Filter according to claim 1, wherein the sleeve rests against an outer side or an inner side of the tubular section or of the cap section, at least in the region of the first end of the filter slots.
6. High-pressure nozzle having a filter according to claim 1.
7. High-pressure nozzle according to claim 6, wherein the sleeve is arranged within the tubular section and forms a flow channel through the filter, at least in some section or sections, and in that a free flow cross section of the sleeve corresponds to the free flow cross section in the nozzle housing at the downstream end of the sleeve.
8. Method for producing a filter for a high-pressure nozzle, including the steps of sawing filter slots into a tubular section and/or a cap section of the filter parallel to a longitudinal direction of the tubular section and arranging a sleeve coaxially with the tubular section, with the result that the sleeve covers the filter slots in the region of a first end of the filter slots.
9. Method according to claim 8, including arranging the sleeve within the tubular section and/or the cap section.
10. Method according to claim 8, including arranging the sleeve on an outer side of the tubular section and/or of the cap section.
11. Method according to claim 8, including arranging the sleeve coaxially with the tubular section so that the sleeve covers the filter slots in an end region of the filter slots situated adjacent the tubular section.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 shows a high-pressure nozzle according to the invention in a view obliquely from below,
[0029] FIG. 2 shows a view of the high-pressure nozzle of FIG. 1 from behind,
[0030] FIG. 3 shows the high-pressure nozzle of FIG. 1 in a side view,
[0031] FIG. 4 shows the high-pressure nozzle of FIG. 1 in a front view,
[0032] FIG. 5 a view of section plane A-A in FIG. 3,
[0033] FIG. 6 a view of the filter of the high-pressure nozzle of FIG. 1 obliquely from above,
[0034] FIG. 7 a view of the filter of FIG. 6 from behind,
[0035] FIG. 8 a side view of the filter of FIG. 6,
[0036] FIG. 9 a view of the filter of FIG. 6 from the front,
[0037] FIG. 10 a view of section plane A-A in FIG. 8,
[0038] FIG. 11 a sectional view of a filter according to the invention for a high-pressure nozzle according to another embodiment,
[0039] FIG. 12 a connection nipple with a high-pressure nozzle according to the invention fitted,
[0040] FIG. 13 a view of section plane A-A in FIG. 12 and
[0041] FIG. 14 the enlarged view of detail Y in FIG. 13.
DETAILED DESCRIPTION
[0042] The illustration in FIG. 1 shows a high-pressure nozzle 10 according to the invention, wherein the high-pressure nozzle 10 has a housing 12, a nozzle 14, only a section of which can be seen in FIG. 1, and a filter 16 connected to the housing 12.
[0043] Liquid to be sprayed enters the filter 16 through a plurality of filter slots 18 extending in the longitudinal direction of the filter and passes through them into a flow channel (not visible in FIG. 1) in the interior of the nozzle housing 12. The liquid to be sprayed passes to the nozzle mouthpiece 14 and specifically to the outlet opening in the nozzle mouthpiece 14 and emerges in the form of a fan jet in the embodiment shown.
[0044] The high-pressure nozzle 10 shown is provided for descaling steel products. A pressure of the liquid to be sprayed is typically in a range of from about 50 bar to several 100 bar, e.g. 800 bar. The mechanical requirements on the high-pressure nozzle 10 are therefore considerable since pressure surges can occur in the pipes leading to the high-pressure nozzle 10, and these can then also have significantly higher pressure spikes. The filter 16 normally projects into a pipe through which the liquid to be sprayed is supplied. As a result, the filter 16 is exposed to high mechanical stresses, and turbulence which occurs as the liquid to be sprayed enters through the filter slots 18 also affects the performance of the high-pressure nozzle 10 in a disadvantageous way.
[0045] The illustration in FIG. 2 shows the high-pressure nozzle 10 of FIG. 1 from behind, i.e. as seen in the direction of flow. It can be seen that the filter slots 18 are arranged in a radial direction in the filter 16.
[0046] In the embodiment shown, the filter 16 has a tubular section 20 and a cap section 22. The filter slots 18 extend in the longitudinal direction of the tubular section 20 and are arranged both in the cap section 22 and in the tubular section 20.
[0047] From the ends of the filter slots 18 in FIG. 1 and FIG. 2, it can be seen that these are made using a circular saw blade which ends in a linear edge at its circumference. For this reason, each of the ends of the filter slots 18 also runs out in an edge. In the context of the invention, provision is likewise made here to make the filter slots 18 with a saw blade which is of rectangular configuration at its circumferential edge.
[0048] The illustration in FIG. 3 shows a side view of the high-pressure nozzle 10. In this view too, the filter slots 18 introduced in the longitudinal direction of the tubular section 20 can be seen, extending from the cap section 22 into the tubular section 20. In the illustrated embodiment of the high-pressure nozzle 10, a circular-cylindrical section of the filter 16 is referred to as the tubular section 20. The approximately hemi-spherical section which closes off one end of the tubular section 20 is then referred to as the cap section. In the embodiment illustrated, the filter 16 is of integral design. The filter 16 can be produced from a turned brass cap, into which the filter slots 18 are sawed, for example.
[0049] The illustration in FIG. 4 shows the high-pressure nozzle 10 of FIG. 1 from the front. In addition to the nozzle housing 12, the nozzle mouthpiece 14 with the outlet opening 24 can be seen.
[0050] The sectional view in FIG. 5 enables the configuration of the filter slots 18 to be seen. The filter slots 18 each have a first end 26 and a second end 28, wherein the first end 26 is situated on the side of the tubular section 20 and the second end 28 is situated on the side of the cap section 22. The first end 26 is thus arranged at the downstream end of the filter slots 18 in the direction of flow through the high-pressure nozzle 10 and the second end 28 is arranged at the upstream end of the filter slots 18, as seen in the direction of flow. As already explained, both ends 26, 28 taper to an edge. This is brought about by the fact that the filter slots 18 are sawed using a circular saw blade that tapers at the edge. As already explained, the ends 26, 28 of the filter slots 18 can also be of rectangular configuration if they are sawed using a saw blade of rectangular edge design.
[0051] In the illustration in FIG. 5, the filter slots 18 are sawed from the right. The circular saw blade is moved from right to left and thus cuts through the cap section 22 first and then enters the tubular section 20. The feed motion of the saw blade is then stopped and the shape of the first end 26 of the filter slots 18, which is arranged on the left in FIG. 5, is obtained. The shape of the first end 26 follows the outer contour of the saw blade and consequently forms a convex surface. Towards the centre of the filter 16, this surface merges into a sharp edge, although this cannot be seen in the illustration in FIG. 5 since a sleeve 30 is already arranged there. However, it can be seen in the illustration in FIG. 11 how the edge at the transition between a central bore 32 of the filter 16 to the filter slots 18 is designed. More specifically, this circumferential edge follows a zigzag line caused by the configuration of the saw blade. The configuration of this edge in FIG. 11 arises because a saw blade with a circumferential tapering edge is used. If, instead, a saw blade with an edge which does not taper but is rectangular is used, it would not be a zigzag line but an edge which was obtained, said edge being characterized by a plurality of grooves which are arranged spaced apart and are each rectangular.
[0052] In all cases, the profile of this sharp edge is of unfavourable configuration for flow and contributes to the generation of turbulence. To prevent the formation of such turbulence or at least to prevent it as far as possible, the sleeve 30 in the nozzle according to the embodiment in FIG. 5 is inserted into the filter. For this purpose, the central bore of the filter is of step-shaped design, thus allowing the sleeve 30 to be inserted into the filter from the left as far as an offset 34 in the illustration in FIG. 5. The offset 34 is situated upstream of the first ends 26 of the filter slots 18, as seen in the direction of flow. As a result, liquid which enters the filter 16 from outside through the filter slots 18 must flow into that end of the sleeve 30 which is situated upstream and on the right in FIG. 5. It can be seen from FIG. 5 that, as a result, the shape of the first end 26 of the filter slots 18 plays virtually no role anymore in relation to the liquid flowing in. This is because the decisive inlet edge for the liquid is now defined by that end of the sleeve 30 which is situated upstream and on the right in FIG. 5. As a consequence, there is now only a weak flow through the first end 26 of the filter slots since, of course, the sleeve 30 covers the filter slots 18 in the region of the first end 26.
[0053] A central bore of the sleeve 30 is embodied so as to widen at its upstream end, i.e. the end situated on the right in FIG. 5. More specifically, a cone 36 which widens counter to the direction of flow is provided in the embodiment illustrated. The liquid to be sprayed enters via this cone 36, which then tapers in the direction of flow. The flow resistance at the inlet to the sleeve 30 is thereby reduced. The end face of the sleeve 30 directed counter to the flow, i.e. the end face of the sleeve 30 arranged on the right in FIG. 5, can furthermore be of rounded design in order to further reduce a flow resistance. It should be taken into account here that it is only in the region of the filter slots 18 that this end face of the sleeve 30 arranged on the right in FIG. 5 is impinged upon by the liquid to be sprayed. Between the filter slots 18, the webs which separate the filter slots 18 also cover the end face of the sleeve 30.
[0054] The illustrations in FIGS. 6 to 10 show the filter 16 before assembly with the nozzle housing 10. The filter 16 is secured in the housing 10 by means of a cylindrical section 38, which can be provided with a thread.
[0055] The filter 16 is provided with two opposite, flat engagement surfaces 40 for a spanner to enable the filter 16 to be screwed into the housing 10.
[0056] As already mentioned, the illustration in FIG. 11 shows another embodiment of a filter 16 according to the invention. To avoid repetitions, only those features are described here which differ from those in the filter shown in FIGS. 1 to 10.
[0057] The filter 16 in FIG. 11 is provided with a sleeve 42, which rests against a radially outer outer surface of the filter 16. As a result, the sleeve 42 covers the first ends 26 of the filter slots 18 and thereby prevents the shape of the first ends 26 of the filter slots 18 from being able to cause increased turbulence and, as a result, increased flow resistance, as the liquid to be sprayed enters the filter 16.
[0058] More specifically, it can be seen from FIG. 11 that the liquid flows directly into the filter slots 18 from that end of the sleeve 42 which is situated on the right in FIG. 11, i.e. the upstream end. In the region of the first ends 26 of the filter slots 18, in contrast, there is only a negligible flow. As a result, the shape of the first ends 26 of the filter slots 18, which is determined by the sawing of the slots by means of a circular saw blade, causes only slight turbulence and only slightly increased flow resistance.
[0059] Since the sleeve 42 is mounted on the outside of the filter 16 in FIG. 11 and rests on the outer surface of the filter 16, the central bore 32 of the filter 16 itself forms a section of the flow channel through the high-pressure nozzle.
[0060] Both in the embodiment in FIGS. 1 to 10 and the embodiment in FIG. 11, it has been found that, by virtue of the sleeves 30 and 42, each covering the first ends 26 of the filter slots 18, the ends situated on the side of the tubular section 20 of the filter 16, the liquid to be sprayed is subject to so little turbulence after entering the filter 16 that it is normally possible to dispense with a jet straightener in the rest of the flow channel up to the outlet opening 24. As a result, the high-pressure nozzle 10 according to the invention can be manufactured at low cost and, since a jet straightener always also causes flow resistance, is extremely powerful. More specifically, an impact, i.e. a contact impulse of the fan jet produced on a surface to be descaled, is greater in comparison with conventional nozzles according to the prior art.
[0061] If the inlet flow to the filter is very unfavourable, a jet straightener can have a calming effect on the flow. A jet straightener can be provided in the high-pressure nozzle according to the invention and can be installed in the sleeve 30, for example.
[0062] The illustration in FIG. 12 shows a connection nipple 50, in which the high-pressure nozzle 10 according to the invention is installed, in a side view. In the view in FIG. 12, however, the high-pressure nozzle 10 is not visible. The connection nipple 50 has a tubular section 52, onto the free end of which, at the top in FIG. 12, a union nut 54 is screwed.
[0063] In the sectional view in FIG. 13 in section plane A-A in FIG. 12, it can be seen that the housing 12 of the high-pressure nozzle is preloaded against the connection nipple 52 by means of the union nut 54. The high-pressure nozzle 10 is thereby held reliably and yet in an easily exchangeable manner on the connection nipple 52. The connection nipple 52 can mark the end of a pipe via which the liquid to be sprayed is supplied. However, the connection nipple 52 can also be welded into a pipe extending perpendicularly to the connection nipple 52, for example.
[0064] The illustration in FIG. 14 shows the enlarged detail Y in FIG. 13. It shows the outlet opening 24, from which a fan jet emerges and which is provided on a nozzle mouthpiece 14. When viewed counter to the direction of flow, that is to say from top to bottom in FIG. 14, the mouthpiece 14 is followed within the nozzle housing 10 first of all by a ring seal 56, then by an intermediate sleeve 58 and then, if appropriate with the interposition of a further ring seal (not shown), the sleeve 30, which is inserted into the filter 16. It can be seen that the diameter of a flow channel in the sleeve 30 corresponds to the diameter of the flow channel at the upstream end of the intermediate sleeve 58. As a result, the liquid to be sprayed can be passed to the outlet opening 24 with small pressure losses.
[0065] The nozzle mouthpiece 14 advantageously consists of hard metal in order to ensure a long service life of the high-pressure nozzle 10.
