Nozzle for Forming a Free Jet Stream of a Liquid, and Its Method of Manufacture

The present invention relates to a nozzle for forming a free jet stream of a liquid, and a method of manufacturing such a nozzle. More particularly, the invention relates to such a nozzle (and its method of manufacture) especially designed to provide a free jet stream which will maintain a desired configuration with a minimum of thickness and surface fluctuations and variations in its velocity profile.

As used herein, the terminology "free jet stream of liquid" means a stream of liquid which flows unconfined (free) from a supply under pressure. Such a jet stream typically is formed by a nozzle which imparts to the liquid prior to the time the same flows into an ambient atmosphere, a desired configuration, etc.

It is important in many processes or apparatus employing a free jet stream of liquid that the same maintain uniform characteristics for a time after it leaves a nozzle, at least over a selected portion of its cross sectional configuration. The present invention is directed to a nozzle for forming such a stream designed to assure that the interface between the liquid in the nozzle and the solid components of the nozzle do not interfere with such stream maintaining its integrity after flowing from such nozzle.

The present invention provides a nozzle having a sharp edge at its exit aperture that essentially has minimum imperfections to interact with liquid flowing outwardly of the nozzle at such edge. This is accomplished by forming the exit aperture edge of the nozzle in a particular way. That is, such edge is provided by the intersection of a pair of faces of a block of material, and is formed by first positioning such block against a supporting block with one of its faces generally coplanar with a corresponding face of the supporting block and the edge in contact with the supporting block. The coplanar faces of the two blocks thereafter are simultaneously polished (material is removed from the same) while the edge is overlapped so that the edge is fully supported during such polishing to become the desired sharp edge. Most desirably, the supporting block is itself a block of material having first and second faces which intersect to define an edge intended to provide another edge for the nozzle exit aperture, so that such overlapped polishing provides two separate edges for the exit aperture having a minimum of imperfections.

Provision of optically flat side wall surfaces for the liquid channel of the nozzle immediately adjacent the exit aperture, is also comprehended as part of the invention. This assures that such side walls do not introduce unwanted liquid perturbations in the stream. Moreover, the nozzle liquid channel is defined by a plurality of blocks of material with the result that prior to assembly of the nozzle, access can be had easily to the channel side wall surfaces and the exit aperture edges for conditioning as discussed above. When the nozzle is assembled, these blocks are placed in optical contact with one another as discussed infra, at all points of their engagement exposed to flowing liquid. Thus, the block interfaces exposed to the liquid do only introduce minimum unwanted perturbations in the liquid stream.

The invention includes other features and advantages which will be described or will become apparent from the following, more detailed description of preferred embodiments.

With reference to the accompanying single sheet of drawing:

FIG. 1 is an elevation view of a preferred embodiment of a nozzle of the invention, shown partly in section and partly in schematic;

FIG. 2 is an enlarged, sectional view of the end of the nozzle of FIG. 1, taken on a plane indicated by the lines 2--2 in FIG. 1;

FIG. 3 is a schematic illustration of blocks of material from which the nozzle end of the preferred embodiment of the invention is formed;

FIGS. 4-6 illustrate schematically, sequential steps of the process of the instant invention for forming the nozzle end; and

FIG. 7 schematically illustrates in operation a finished assembly of the parts defining the exit aperture of the preferred embodiment of the nozzle .

With reference first to FIG. 1, a nozzle of the invention, generally referred to by the reference numeral 11, is illustrated schematically supplied with liquid as represented at 12 from a liquid pump 13.

Nozzle 11 is designed to project into an ambient atmosphere, a jet of a liquid stream which will be rectangular in cross section and have a uniform, well defined thickness between two opposed faces. Moreover, nozzle 11 is designed to assure that minimum imperfections or the like are present to perturb either the uniform shape or velocity of the liquid within the jet. It is the end assembly 14 of nozzle 11 which defines the emitted jet stream. The remainder of the nozzle is included to deliver liquid for forming the jet stream to the end 14 and provide in a very general way, some definition to the stream. An outer casing or cylinder 16 is provided within which an insert 17 is maintained by a plurality of cap screws 18. A liquid hose coupling 19 is threadably received within insert 17, and acts to connect the remainder of the nozzle to a hose provided with liquid under pressure.

As mentioned previously, it is the exit end assembly 14 of nozzle 11 which is responsible for the final configuration and characteristics of the free jet stream. A liquid channel 21 for forming the jet stream (FIG. 2) is defined in such end by a plurality of blocks 22, 23, 24, and 26. As will be discussed below, blocks 23 and 26 are formed by slicing through a larger block, and thus are sometimes referred to herein as "block parts", rather than full "blocks".

In keeping with the invention, the blocks 22-24 and 26 define both the liquid channel 21 and the ultimate exit aperture for the fluid stream in a manner which will prevent that portion of the nozzle structure engaged with the stream immediately before it enters the ambient atmosphere, from interfering with the configuration and velocity profile of the stream exiting such nozzle. In this connection, it is first important to note that the channel 21 is therefore made up of a plurality of parts which assure that simple access can be had to the channel side walls and the exit aperture edges for appropriate conditioning, before the nozzle is assembled.

The characteristics of the material from which the blocks 22-24 and 26 are made, are particularly important for the preferred arrangement. First of all, the material should be one which can be polished on a surface to be optically flat. The term "optically flat surface" is generally known in the trade. In qualitative terms, such a surface is one which is sufficiently flat to form an optical contact (as that term is defined hereinafter with another "optically flat" surface produced independently of the first surface. Most desirably, for the purposes of the instant invention, an optically flat surface is one that has no variation from a mean flat plane, greater than about 0.135 microns.

For example, the fused silica sold by Heraus-Amersil, Inc. of Sayreville, N.J., with the designation T08 Commercial has this capability.

In the manufacture of nozzle end 14, three rectangular blocks of material from which the blocks 22, 23, 24 and 26 are to be made are first furnished. The blocks from which blocks 22 and 24 are to be made are provided with slightly larger dimensions that it is intended the finished blocks have in the final nozzle end assembly, to permit subsequent polishing as described. In one embodiment, the finished blocks in the final end assembly are 5.43 by 11.20 mm with a height of 15.0 mm. The unfinished blocks of material are respectively referred to in the drawings by the primed reference numerals 22' and 24'. Such blocks 22' and 24' are each cut and ground to provide a solid rectangle, and it is preferred that the sides of each (the larger faces) be provided with an optical quality finish.

Blocks 23 and 26 are actually formed as block parts by slicing a third block of material. This third block of material is represented in FIGS. 3 and 4 and denoted by the reference numeral 27. It is also rectangular and if the finished blocks 22 and 24 have the dimensions set forth above, it desirably is large enough to have a finished thickness of 0.35 mm and a finished height of 15.0 mm.

It will be noted that in the final nozzle assembly, two opposed faces of blocks 22 and 24 define the broad side wall surfaces of the liquid channel. In keeping with the invention, the block faces which are to provide such side wall surfaces should be polished to be optically flat as defined above. FIG. 3 schematically illustrates such polishing. The arrows 28 and 29 refer to the surfaces which are polished to be optically flat. As illustrated, the opposite surface of one of the blocks (block 24' in FIG. 3) is also polished to be optically flat. This is indicated by arrow 30. Moreover, one of the broad faces of block 27 is also polished to be optically flat, as denoted by arrow 31.

The surfaces of the blocks 22' and 24' which are to be polished to optically flat surfaces, are polished sufficiently to make the thickness of each of such blocks below the polished surfaces equal to the final dimension desired when such blocks are assembled with the remainder of the nozzle components. However, block 27 should have enough extra thickness after the polishing represented by arrow 31 to allow the opposite surface also to be polished optically flat as discussed below.

After the surfaces designated by the arrows 28-31 are made optically flat, the three blocks are assembled together with such surfaces optically contacting one another. That is, such surfaces are cleaned, the surface designated by the arrow 28 of block 22' is intimately engaged with one of the surfaces designated by the arrows 29 and 30 of the block 24', and the surface designated by the arrow 31 of block 30 is brought into intimate contact with the other optically flat surface of block 24'. As is known, intimate engagement of clean, optically flat surfaces with one another will result in a bond at the surface interface which requires a force at least equal to atmospheric pressure to separate the members. In other words, essentially all atmosphere will be excluded from between the blocks at the interface. This bond is due to molecular adhesion between the materials of the two surfaces in intimate engagement. Such an intimate engagement between surfaces is referred to in the art and herein as an "optical contact" therebetween.

As schematically represented in FIG. 4, the blocks 22', 24' and 31 are placed in optical contact with one another with their upper and lower surfaces or faces generally coplanar. As one of the more particularly salient features of the instant invention, the end faces of the blocks 22', 24' and 31 are then polished. This polishing operation is represented in FIG. 4 by the schematic representation of circular polishing pads 33 and 34. It is important to note that such polishing is accomplished overlapping the interfacing edges of the blocks. Each of such edges is in contact with the adjacent block and thus is fully supported along its length during the polishing operation. Some of these block edges form the edges of the jet exit aperture when the blocks are assembled together. Because such edges are fully supported during such polishing or, in other words, material removal, they will each have a minimum of imperfections. That is, such edges will be free of chips (detrimental depressions and discontinuities) and machining chips.

The optical contact during polishing between the faces of the blocks providing such edges, enhances the edge conditioning. More particularly, such optical contact will assure that each of the polished block edges will be in engagement and supported by the adjacent block with an outside tolerance of at the most the sum of the most significant depth variations in each block.

It should be noted that it is not necessary to polish the ends of the blocks optically flat. It is only necessary that such blocks receive at such faces a quality optical polish. That is, such faces need not necessarily be polished to optical flatness in order to obtain the effects of the invention. It should be further noted that this polishing operation provides a plurality of edges for the exit aperture at one time. That is, the blocks 22' and 24' each provide one of the longer edges for the exit aperture. It is not necessary in obtaining the sharp exit aperture edges discussed above that both opposed end faces of the blocks be polished. It is desirable, though, for another reason. That is, it is desirable in the finished nozzle that for sealing purposes all of the blocks be of the same length. The polishing of opposed end faces of the blocks will assure that a common length is achieved. And it is to be noted that it is only for this reason that block 31 is assembled with the blocks 22' and 24' during such polishing.

After the end faces of the blocks are polished as discussed above, the blocks are separated from one another as schematically represented in FIG. 5. Moreover, the block 31 is sliced to define a pair of block parts 23' and 26'. (The use of primed reference numerals denotes that such block parts do not yet have their final dimensions.) It is a narrow side wall of each of the block parts 23 and 26 which form the end side wall faces of the liquid channel. Such faces should be polished to a desired sheen. Such polishing most simply can be accomplished by sandwiching a plurality of such block parts together to provide a workable surface, leaving exposed on opposite sides, the surfaces 36 and 37 of each. Such surfaces are then polished to the desired finish. It is not necessary for the use to which the particular nozzle being described is to be placed, that the narrower ends of the jet stream maintain their integrity. Thus, for this particular embodiment, the surfaces 36 and 37 need not be polished optically flat. However, they should be polished to provide the individual block parts with a dimension between the opposed surfaces of 4.50 mm.

After the surfaces 36 and 37 of the block parts 23' and 26' are suitably polished, such blocks are assembled with the block 22 to begin defining the liquid channel. In this connection, it is to be recalled that one face of each of the blocks 23' and 26' has an optically flat finish. The optically flat surface of each is placed into optical contact with the optically flat surfaces of block 22.

The block parts are suitably spaced apart from one another a distance equal to the desired width of the final channel. Moreover, care should be taken when they are so assembled to assure that the end faces of the blocks 23 and 26 are aligned with the corresponding end faces of block 22.

FIG. 6 schematically illustrates the block parts 23' and 26' positioned against the optically flat face of block 22 as described. After they have been so positioned, the exposed side of blocks 23' and 26' are then polished optically flat. This is represented in FIG. 6 by the showing of polishing head 38. Once they are optically flat, the conditioning of such block parts is finished and the block 24 can be brought into engagement therewith with its end annulus for the nozzle which flares outwardly away from the exit aperture of the channel 21 to assure that flange 41 will not interfere wth the integrity of the liquid stream.

A spacer ring 42 is placed within the housing 16 adjacent its end. The nozzle end assembly 14 is then inserted within such housing to rest on such spacer ring. In this connection, it is important for this particular embodiment that the blocks 22-24 and 26 have the same length and be coextensive with one another so that their ends abutting against spacer ring 42 are coplanar. A second spacer ring 43 is then inserted on the nozzle end assembly to isolate the same from the remainder of the structure. The spacer rings 42 and 43 can be of teflon, and act as a seal to prevent liquid, particularly liquid under pressure in insert channel 44, from seeping around nozzle end assembly 14.

Insert 17 is inserted within the housing after spacer ring 43 is placed into position, and cap screws 18 are threadably received within the housing to maintain such insert in place. Coupling 19 can then be threadably received within the insert.

A pair of set screws 46 of nylon or other soft materials are threadably received within the housing 16 adjacent the nozzle end assembly 14 at locations opposite one another about the periphery of such housing. As illustrated, the ends of such set screws engage the nozzle end assembly. They are provided to enable shifting of the position of such assembly within the housing as desired to obtain a selected alignment of the channel 21 relative to the remainder of the structure. The space between the nozzle end assembly and the housing can then be filled with a potting compound as represented at 47 to fill all volume at the nozzle end except for that defined by the liquid channel.

Although the invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that various changes and modifications can be made without departing from its spirit. Moreover, several aspects of the same can be used advantageously independently of the others. For example, in some instances optically flat channel side walls can be advantageously employed irrespective of whether or not the edges of the liquid exit aperture are conditioned as described. It is therefore intended that the coverage afforded applicant be limited only by the claims and their equivalent language.