GB2093372A

GB2093372A - Fan spray nozzle

Info

Publication number: GB2093372A
Application number: GB8201407A
Authority: GB
Original assignee: Albany International Corp
Current assignee: Albany International Corp
Priority date: 1981-02-19
Filing date: 1982-01-19
Publication date: 1982-09-02
Also published as: CA1186354A; GB2093372B

Abstract

A fan spray nozzle 10 comprises a tube having in its wall a fan spray opening formed by a passage 14 of relatively large diameter leading to a conically tapering portion 16, which is intersected by an arcuate groove 18, which is formed in the exterior surface 22 of the tube and the length of which is substantially parallel to the longitudinal axis of the tube. The width of the arcuate groove is smaller than the diameter of the passage 14. The spray opening is formed by a method which includes drilling a pair of diametrically opposed small pilot holes through the tube, drilling completely through one of the pilot holes and through a portion of the opposing hole with a bit having a larger diameter than the pilot holes to form the passage 14 and the tapering portion 16 and the cutting the arcuate groove 18 in the exterior surface of the wall of the tube. The groove 18 intersects the portion 16, and after completion of the spray opening, the pilot hole which has been completely drilled through is sealed with a plug 30. The nozzle has no crevices or joints between parts which could harbour bacteria, but the spray openings produce effective fan sprays. <IMAGE>

Description

SPECIFICATION Fan spray nozzle This invention relates to spray nozzles incorporated in pipes or tubes that serve as water headers. It also relates to methods of making such nozzles.

Spray openings have been machined in the walls of water headers, but they have not resulted in a fan spray nozzle which provides a well defined spray pattern. To generate a good spray pattern, each opening has been machined in a flat disc that is subsequently attached to a tube by means of soldering, welding, or screw threads.

Spray nozzles of the above-mentioned types are shown by way of example of U.S. Patents Nos.

169,355,1,151,958,2,834,635 and 3,647,147.

In spray nozzles used, for example in the food industry, there should not be any crevices or void areas such as small screw threads where bacteria may grow. For this reason in spray nozzles for such purposes multiple drilled holes have been employed because they form a smooth transition with the interior of the water header. Such holes do not, however, produce a superior spray pattern.

The object of the present invention is to provide a fan spray nozzle which is formed by machining openings in the wall of a water header and the geometry of which is such that a desirable spray pattern is obtained from the nozzle.

The invention also provides, according to another of its aspects, a method of forming such nozzle openings in an efficient manner.

The nozzle in accordance with the invention is especially useful within a cheese filter, but other uses are also contemplated.

According to one aspect of the invention, a fan spray nozzle comprises a substantially cylindrical tube having at least one fan spray opening extending through its wall, the, or each, opening comprising a passage extending radially from the interior surface of the wall of the tube to a position between the interior and exterior surfaces of the wall, the passage having a relatively large cross sectional area in a first portion thereof adjacent the interior surface of the wall and a relatively small cross sectional area in a second portion thereof adjacent the position between the interior and exterior surfaces, and a groove of arcuate longitudinal section formed in the wall of the tube and extending inwardly from the exterior surface, the groove having its length extending substantially parallel to the longitudinal axis of the tube and a portion of the groove intersecting the portion of relatively small cross sectional area of the passage.

The method of making a nozzle in accordance with the invention consists in providing a substantially cylindrical tube, drilling a first pair of coaxial, diametrically opposed holes of relatively small diameter through the wall of the tube, enlarging the diameter of one of the pair of diametrically opposed holes by drilling coaxially therethrough with a drill bit having a larger diameter than the diameter of the diametrically opposed holes, enlarging the diameter of a radially inner portion of the other of the diametrically opposed holes to form the passage by passing the drill bit through the one of the holes and across the interior of the tube until it contacts the interior surface of the tube surrounding the other of the holes, drilling along the axis of the other hole, and stopping drilling before the bit reaches the exterior surface of the tube so that the other hole comprises a first cylindrical hole portion extending within the wall of the tube from the interior surface thereof to a position between the interior surface and the exterior surface and a second hole portion of smaller diameter than the first hole portion extending from the said position towards the exterior surface, and grinding or milling an arcuate groove in the exterior surface of the wall, the groove extending inwards from the exterior surface of said tube and intersecting the second hole portion at a depth which is between the exterior surface of the said wall and the said position, the groove having its length substantially parallel to the longitudinal axis of the tube.

Preferably, the second hole portion bisects the length of the arcuate groove and accordingly has an opening at the deepest point of the groove.

The first one of the pair of diametrically opposed holes is plugged or otherwise closed so that the wall of the tube is of uniform thickness opposite the spray opening.

An example of a spray nozzle, and of a method of making the spray nozzle, in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a perspective view of the spray nozzle which is formed by a water header with a plurality of spray openings formed therein; Figure 2 is a plan view to a larger scale of a portion of the spray nozzle shown in Figure 1; Figure 3 is a sectional view as seen in the direction of the arrows on the line 3-3 of Figure 2; Figure 4 is a sectional view showing a preliminary stage before the formation of one of the openings in the header; Figure 5 is a sectional view of the diametrically opposite side of the header shown in Figure 4 showing a first stage in the formation of one of the openings in the header;; Figure 6 is a sectional view similar to Figure 4 but showing a later operation in the formation of the opening; Figure 7 is a sectional view similar to Figure 5, but at a later stage of the formation of the opening; and Figure 8 is a cross sectional view of the header after completion of the formation of the opening as seen in the direction of the arrows on the line 8-8 of Figure 3.

A fan spray nozzle comprises a water header, consisting of a stainless steel tube 10 of circular cross section, and a plurality of spray openings 1 2 formed in the tube 10. Each of the spray openings is shaped to produce a well defined fan spray pattern. Since all the openings 12 are identical.

they will be described by reference to only one such opening as shown in Figures 2, 3 and 8.

Each spray opening 12 includes a relatively large cylindrical passage 14 which opens into the interior of the tube 10. The large passage then tapers inwardly to form a conical area 1 6 within the wall of the tube. The cross sectional diameter of the conical portion decreases outwards towards the exterior surface of the tube. Both the cylindrical passage 14 and the conical portion 16 are coaxial with their common axis intersecting the longitudinal axis of the tube 10.

An arcuate groove 1 8 is cut into the exterior surface of the tube 10. The groove 1 8 has a length extending parallel to the longitudinal axis of the tube and a uniform width which is smaller than the diameter of the relatively large passage 14.

The deepest portion of the groove 1 8 intersects the conical portion 1 6 such that a spray orifice 20 is formed in the wall of the tube and a spray opening is formed right through the wall of the tube. The maximum depth of the groove 1 8 should be less than the distance between the outer surface of wall 22 and the radially outermost portion of the cylindrical passage 14. Thus the iength and width of the opening 20 will be relatively small in comparison with the length of the groove 18.

The steps taken in the formation of each opening 12 are shown in Figures 4-8. A hole is first drilled diametrically through the entire tube 10 such that opposing bores 24, 26 of a relatively small diameter are formed. The bores are coaxial and are normal to the exterior and interior surfaces of the tube 10 as shown in Figures 4 and 5.

A larger drill bit 27 is employed after the bores 24, 26 have been formed. Drilling is conducted along the respective axes of the bores 24,26 from one side of the tube into the diametrically opposite side. The bore 24 is uniformly enlarged to form a bigger bore 28 having a relatively large diameter.

The bit 27 proceeds through the hollow interior of the tube and then contacts the interior surface on the diametrically opposite side thereof. It penetrates the wall of the tube from the interior towards the exterior. Drilling is stopped before the wall diametrically opposite the bore 28 is fully penetrated. Owing to the shape of the bit, the cylindrical passage 14 and the conical area 1 6 are formed as shown in Figure 7.

Using a grinding wheel or a milling cutter, the groove 18 is then formed to the above described dimensions. The groove is symmetrical and the end portions 1 8', 1 8" thereof form a smooth transition with the exterior surface of the wall of the tube 10.

The bore 28 opposite the spray opening 12 is finally plugged by means of an appropriate plug 30 as shown in Figure 8. The plug surfaces are then machined so that they are flush with the surfaces of the tube wall. Welding or soldering operations may be employed in the plugging of the bore 28.

In operation, water pressure within the tube 10 causes water to be sprayed from the openings 12, of which there may be only one, in desirable fan spray patterns. There are no cracks or crevices where bacteria can accumulate, thus making the nozzle safe for any operation where such spray patterns are desired. In the embodiment described above, the wall of the tube is about 4.8 mm thick and the length of the groove is about 14.3 mm.

The internal diameter of the tube is approximately 17.5 mm. These dimensions may of course be varied.

Claims

1. A fan spray nozzle comprising a substantially cylindrical tube having at least one fan spray opening extending through its wall, the, or each, opening comprising a passage extending radially from the interior surface of the wall of the tube to a position between the interior and exterior surfaces of the wall, the passage having a relatively large cross sectional area in a first portion thereof adjacent the interior surface of the wall and a relatively small cross sectional area in a second portion thereof adjacent the position between the interior and exterior surfaces, and a groove of arcuate longitudinal section formed in the wall of the tube and extending inwardly from the exterior surface, the groove having its length extending substantially parallel to the longitudinal axis of the tube and a portion of the groove intersecting the portion of relatively small cross sectional area of the passage.

2. A spray nozzle according to Claim 1, wherein the first portion of the passage is cylindrical and the width of the groove is smaller than the diameter of the first portion of the passage.

3. A spray nozzle according to Claim 1 or Claim 2, wherein the second portion of the passage is conical with its end of larger diameter adjoining the first portion.

4. A spray nozzle according to any one of Claims 1 to 3, wherein the portion of the arcuate groove which intersects the passage is the deepest portion of the groove with respect to the exterior surface of the tube, the groove and the passage forming a nozzle opening which has a radial length and a width which are small compared with the length of the groove.

5. A spray nozzle according to Claim 4, wherein said arcuate groove is symmetrical with respect to the passage and is of uniform width.

6. A spray nozzle according to any one of the preceding Claims, in which the tube is of stainless steel.

7. A method of making a fan spray nozzle in accordance with Claim 1, comprising providing a substantially cylindrical tube, drilling a first pair of coaxial, diametrically opposed holes of relatively small diameter through the wall of the tube, enlarging the diameter of one of the pair of diametrically opposed holes by drilling coaxially therethrough with a drill bit having a larger diameter than the diameter of the diametrically opposed holes, enlarging the diameter of a radially inner portion of the other of the diametrically opposed holes to form the passage by passing the drill bit through the one of the holes and across the interior of the tube until it contacts the interior surface of the tube surrounding the other of the holes, drilling along the axis of the other hole, and stopping drilling before the bit reaches the exterior surface of the tube so that the other hole comprises a first cylindrical hole portion extending within the wall of the tube from the interior surface thereof to a position between the interior surface and the exterior surface and a second hole portion of smaller diameter than the first hole portion extending from the said position towards the exterior surface, and grinding or milling an arcuate groove in the exterior surface of the wall, the groove extending inwards from the exterior surface of said tube and intersecting the second hole portion at a depth which is between the exterior surface of the wall and the said position, the groove having its length substantially parallel to the longitudinal axis of the tube.

8. A method according to Claim 7, further comprising plugging the one of the pair of diametrically opposed holes after it has been enlarged.

9. A method according to Claim 7 or Claim 8, wherein the groove has a width smaller than the diameter of the first cylindrical hole portion of the other hole.

10. A spray nozzle according to Claim 1, substantially as described with reference to the accompanying drawings.

11. A method according to Claim 7, substantially as described with reference to the accompanying drawings.