Method for jet formation and the apparatus for the same

#The present invention relates to the method and device for formation of the high-speed liquid and slurry jets, more particularly to optimal control of the jet geometry.

#In recent years high-speed fluid and slurry jets have become a conventional tool in manufacturing, infrastructure maintenance and environment protection. A number of new non-traditional jet applications are emerging in mining, medicine and defense. These applications range from demolition of buildings and breakage of stones to eye surgery, from cleaning of the ocean bottom and deicing the roads to precision machining.

#Conventionally the jets are formed by expelling a compressed fluid through an opening in a metal or ceramic body termed a nozzle. In most cases the openings are round. This geometry is determined by the conditions of the nozzle fabrication. It is much easier to generate a round opening in a solid body than an opening of any other geometry. The round nozzle minimizes the ratio between the surface and the flow rate of the stream. Thus it minimizes the specific head losses. The stability of the round jets that is its ability to resist decomposition into an array of droplets is maximal.

#The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and together with the description serve to explain the principles of the invention. In the drawings:

#FIG. 1 is a schematic of the slot nozzle depicting the geometries of the plates and the insertion forming the nozzle as well the forces sealing the nozzle.

#Fig. 2 is a schematic of the slot nozzle with the variable external forces distributed across the nozzle.

#As it is shown in FIG. 1 the low 1 and the upper 2 plates are separated by the insertion 3. In this nozzle a fluid being accelerated flows from the inlet 4 to the exit 5. The shape of the channels in the nozzle assures gradual conversion of a round jet entering the nozzle into the slot type flow exiting the nozzle via the opening 5. The most important stage of the jet formation occurs at the vicinity of and within the slot. The opening might contain the converging, straight and diverging regions. The geometry of these regions is selected so that the head losses in the course of the jet formation are minimal. The geometry of the channel containing the fluid including the geometry of the exit cross section is determined by the shapes of plates 1 and 2 and the insertion 3. According to the present invention the width of the opening can be controlled by the geometries of the plates 1 and 2 or the geometries of the insertion 3 which separates plates 1 and 2. The cut off of the insertion 3 determines the width of the slot 5, while the thickness of the insertion determines the width of the slot and thus the thickness of developed jet. Because the external forces 6 applied to plates deform the plates and the insertion, the opening geometry also depend on this forces.

#The action of the external forces generated, for example by fasteners connecting the plates, brings about the deformation of the plates and the insertion. This deformation determines the shape of the opening 5 as well as the sealing of the nozzle. The magnitude of the forces 6 and the topography of the adjoining surfaces of the plates and the insertion assure complete sealing of the nozzle body. Thus the leaks of the fluid from the nozzle are prevented and all supplied fluid exits via the opening in the nozzle. The sealing of the nozzle can be enhanced still further by soldering or brazing the interfaces between plates and between plates and insertion. The interface can also be filled by special grease, glue etc.

#The insertion can comprise layers fabricated of various plastic, brittle and elastic materials. The properties of the layers can be selected so that the compression of the insertion by the fasteners results in the formation of an effective seal. The insertion can be readily fabricated and replaced.