Multi-stage reversing cavitation generator

Abstract

The utility model relates to a multi-stage reversing cavitation generator, which is characterized in that the inner cavity of a cavitation cylinder is sequentially provided with a rotational flow generator in a spindle shape along the material flow direction, and the periphery of a tail cone is uniformly provided with a plurality of cone spiral grooves; a plurality of tangential holes are uniformly distributed on the circumference of the middle part and are communicated with inlets of the conical spiral grooves; the shrinking block is provided with a reducing hole, a throat and a central hole along the material flow direction, and the tail end is provided with an inner conical surface; the middle section of the double-cone swirler is cylindrical, outer conical surfaces are arranged at the two ends of the double-cone swirler respectively, the outer conical surface of an inlet is attached to the inner conical surface of the contraction block and evenly provided with a plurality of outer rotation diverging grooves dividing flow from the center to the periphery, and the outer conical surface of an outlet is evenly provided with a plurality of inner rotation converging grooves converging from the periphery to an outlet center hole. A plurality of excircle spiral grooves correspondingly communicated with the two ends are formed in the outer cylindrical wall; and the diffusion block is provided with an inner conical surface, a throat opening and a gradually-expanded hole in the material flow direction, and the inner conical surface of the diffusion block is attached to the outer conical surface of the outlet of the double-cone swirler. The cavitation generator is good in cavitation effect and small in flow resistance.

Description

Technical Field

[0001] The utility model relates to a cavitation generator, in particular to a multi-stage reversing cavitation generator, which can be used in food processing, wastewater treatment and other processes and belongs to the technical field of cavitation equipment. Background Art

[0002] The hydraulic cavitation phenomenon is that when a fluid flows through a restricted flow area (orifice, venturi tube, annulus, etc.), the internal pressure drops. When the pressure drops to the saturated vapor pressure of the liquid at that temperature, the liquid begins to vaporize and produce a large number of cavitation bubbles. When the cavitation bubbles flow through the instantaneous expansion flow channel, the liquid pressure rises, and the volume of the cavitation bubbles shrinks sharply until it collapses. At the moment of its collapse, it is accompanied by high temperature, high pressure, strong shock waves and microjets. The huge instantaneous energy released when the cavitation bubble collapses can destroy the chemical chain and accelerate the reaction process. Therefore, hydraulic cavitation is widely used in wastewater treatment, food, and enhanced reaction processes.

[0003] At present, researchers at home and abroad generally believe that the cavitation value δc is used to determine the strength of cavitation. When δc < 1, cavitation may occur. The smaller the cavitation value δc, the more intense the cavitation reaction. It can be seen that the local static pressure P and liquid velocity V are important control parameters. According to the conversion relationship between fluid static pressure energy and kinetic energy, and the inverse relationship between static pressure P and velocity V, it can be concluded that the strength of cavitation is dominated by velocity V and static pressure P, and the boundary conditions through which the fluid flows will also affect cavitation. For industrial hydraulic cavitators, the generation and collapse of cavitation bubbles have always been the research direction.

[0004] The calculation formula of cavitation number Cv is: Cv=2(PP V ) / (ρV 2 ), where C V is the cavitation number, P is the static pressure behind the liquid plate, Pv is the saturated vapor pressure of the liquid, ρ is the density of the liquid, and V is the velocity of the liquid.

[0005] At present, the design of cavitators at home and abroad basically relies on single-stage or multi-stage fixed-hole plates in series or the annular gap formed between the internal bluff body and the external cavity to force the fluid to intercept, increase the flow rate rapidly, and lose pressure to produce cavitation bubbles. When the cross-section through which the fluid flows increases, the pressure increases, and the bubbles collapse, the effect of strengthening the reaction is achieved.

[0006] The cavitation number Cv (cavitation intensity) increases with the increase of the local static pressure of the liquid and decreases with the increase of the velocity of the cavitation element hole or narrow throat. Studies have shown that under ideal conditions, cavitation usually begins to occur when Cv=1 (Cv start); when Cv<1, the cavitation effect is significant. However, in many cases, due to the presence of a small amount of dissolved gas and suspended particles, cavitation bubbles can also be generated when CV is greater than 1. Dissolved gases and suspended particles are responsible for generating the nuclei required to initiate cavitation. Although the smaller the Cv value, the more cavitation bubbles are generated, the lower the intensity of cavitation bubble collapse, blocking cavitation, the so-called super cavitation, cavitation bubbles begin to merge with each other to form a cavitation cloud, and the fluid is transformed from a two-phase bubble flow to a two-phase annular jet. The central liquid core is covered by an annular steam cloud, which is not conducive to the generation of more energy and active free radicals. In conventional sewage treatment, the cavitation state should be between initial cavitation and blocked cavitation.

[0007] The Chinese utility model patent application with publication number CN 219823720U discloses a forced swirl cavitation generator, comprising a cavitation cylinder, the inner cavity of the cavitation cylinder is provided with: a contraction block, a contraction block gradually contracting hole, a contraction block throat and a gradually expanding contraction block center hole in the direction of material flow; a double-cone vortex finder, which is cylindrical, the outer wall of the inlet end is evenly provided with a plurality of external rotation diverging grooves that diverge from the center to the periphery, the outer wall of the outlet end is evenly provided with a plurality of internal rotation converging grooves that converge from the periphery to the outlet center hole, and the outer cylindrical wall is provided with a plurality of outer circular spiral grooves corresponding to the external rotation diverging grooves and the internal rotation converging grooves; a diffuser block, a diffuser block throat and a diffuser gradually expanding hole are provided in the direction of material flow; a central dispersion cone is provided at the center of the inlet end of the double-cone vortex finder, and the central dispersion cone is inserted into the tail end center of the contraction block center hole; the diffuser block throat is connected to the outlet center hole of the double-cone vortex finder. The cavitation intensity can be controlled by adjusting the gap between the cone rings in the utility model. However, compared with the small hole structure, the narrow ring surface formed by the cone gap has the disadvantages of narrow cavitation range and overall unevenness. Utility Model Content

[0008] The purpose of the utility model is to overcome the problems existing in the prior art and provide a multi-stage reversing cavitation generator that can create a flow field of high shear flow, strong turbulence, and rotating vortex, so that fluid materials can be quickly dispersed, fully and evenly mixed with low flow resistance.

[0009] In order to solve the above technical problems, the utility model provides a multi-stage reversing cavitation generator, comprising a cavitation cylinder, a material inlet is arranged at the center of the front end cover of the cavitation cylinder, a material outlet is arranged on the circumferential wall at the end of the cavitation cylinder, and the inner cavity of the cavitation cylinder is provided with the following in sequence along the material flow direction:

[0010] The swirl generator is in the shape of a spindle with a large middle and small ends, and a generator flange is provided at the large diameter in the middle; a plurality of conical spiral grooves are evenly arranged on the outer circumference of the tail cone; a plurality of tangential holes are evenly distributed on the circumference of the generator flange and communicated with the inlet ends of each conical spiral groove;

[0011] The contraction block is provided with a contraction block gradually contracting hole, a contraction block throat and a gradually expanding contraction block center hole along the material flow direction, and a contraction block inner cone surface is provided at the end;

[0012] The double-cone vortex flow generator has a cylindrical middle section and outer conical surfaces at both ends. The inlet outer conical surface fits the inner conical surface of the contraction block. A plurality of outward-spinning diverging grooves for diverting from the center to the periphery are evenly arranged on the inlet outer conical surface. A plurality of inward-spinning converging grooves for converging from the periphery to the outlet center hole are evenly arranged on the outlet outer conical surface. A plurality of outer-circular spiral grooves corresponding to the outward-spinning diverging grooves and the inward-spinning converging grooves are arranged on the outer cylindrical wall.

[0013] The diffuser block is provided with an inner conical surface of the diffuser block, a diffuser block throat and a diffuser block gradually expanding hole along the material flow direction. The inner conical surface of the diffuser block is in contact with the outer conical surface of the outlet of the double-cone vortex finder, and the diffuser block throat is connected with the outlet center hole of the double-cone vortex finder.

[0014] As an improvement of the utility model, an inner tube column is embedded in the outlet of the gradually expanding hole of the diffuser block, the end of the inner tube column abuts against the center of the rear end cover, the rear end cover covers the rear port of the cavitation cylinder, and a plurality of radial small holes are evenly arranged on the circumferential wall of the inner tube column, which are connected with the end inner cavity of the cavitation cylinder.

[0015] As a further improvement of the utility model, a piston is provided in the inner tube column, the center of the rear end face of the piston is connected to the adjusting rod, the middle section of the adjusting rod passes through the center of the rear end cover and is sealed by a shaft seal, the end threaded section of the adjusting rod is screwed into the screw hole of the fixing seat, the root of the fixing seat is fixed on the rear end cover, and a hand wheel is installed at the end of the adjusting rod.

[0016] As a further improvement of the present invention, the outward-turning divergent groove extends outward along the vortex line or the involute, and the inward-turning converging groove extends inward along the vortex line or the involute.

[0017] Compared with the prior art, the utility model has achieved the following beneficial effects: 1. The tangential rotation, spiral contraction, radial rotation dispersion and centripetal convergence of the fluid are realized inside a cavitator, and the axial flow is transformed into radial flow. It creates a flow field of high shear flow, strong turbulence and rotating vortex, allowing the material to quickly disperse into dense ultra-fine droplets, destroying the boundary contact barrier between reactants in chemical reactions, and making the reaction process faster and more complete; at the same time, a small amount of volatile components hidden in the material quickly lose pressure at narrow joints or small holes to produce a large number of tiny nano-scale cavitation bubbles. The energy of the microjets and shock waves generated when the nanobubbles collapse as the fluid pressure recovers is instantly released in a complex and narrow small area, thereby directly acting on the reactants, and the curved wall produces multiple vortex collision effects. These effects are incomparable to traditional stirring and mixing.

[0018] 2. The small hole at the front end of the swirl generator in the cavitation generator is designed to be tangential. The fluid is forced to rotate at high speed after passing through the small hole. At the same time, due to the sudden contraction of the flow cross section at the small hole, the flow velocity of the fluid increases here, and the static pressure drops sharply, generating a large number of cavitation microbubbles. The bubbles implode and collide in the subsequent expanding spiral channel along with the flow of the fluid. In addition, there are multiple spiral blades with gradually decreasing diameters at the rear end of the cyclone, which greatly enhances the action time and intensity of the fluid reaction, providing an effective implementation plan for the realization of intermolecular collisions and nano-scale micro-scale particle reactions.

[0019] 3. Compared with the cylindrical vortex finder, the improved double-cone vortex finder has lower fluid flow resistance and is more energy-efficient. The spiral grooves on the double-cone surface have a longer flow path, which prolongs the contact opportunities of intense collision, high turbulence, and high shear between fluids, thereby strengthening the reaction process.

[0020] 4. The last stage of the cavitator uses an inner tube column plus radial small holes and a piston structure, which can also control the intensity of cavitation online. First, cavitation occurs at the small holes opened radially in the inner tube column. The cylindrical structure is significantly better than the flat plate in terms of force, so the wall thickness is thinner, the fluid resistance is small, and energy consumption is reduced. At the same time, the number of small holes opened radially in the cylinder is more flexible in spatial arrangement than the circular flat plate and is not limited by the cross-section of the cavity. Second, the axial movement of the piston mounted on the shaft changes the cross-sectional area of ​​the fluid flow, thereby changing the flow rate and changing the cavitation intensity; in addition, the movement of the piston has the effect of scraping the inner wall of the cylinder, which provides an optimal solution for the problem of small hole blockage caused by particle-containing fluids or deposition after shutdown, replacing the original additional backwashing system or even the shutdown and disassembly of the equipment for cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. The accompanying drawings are only provided for reference and explanation and are not intended to limit the present invention.

[0022] Figure 1 This is a front view of the multi-stage reversing cavitation generator of the utility model;

[0023] Figure 2 for Figure 1 A three-dimensional diagram of the swirl generator;

[0024] Figure 3 for Figure 1 A three-dimensional view of the double-cone vortex finder;

[0025] In the figure: 1. Cavitation cylinder; 1a. Material inlet; 1b. Material outlet; 2. Positioning nut; 3. Swirl generator; 3a. Large guide cone; 3b. Generator flange; 3c. Tangential hole; 3d. Conical spiral groove; 4. Contraction block; 5. Double-cone vortex generator; 5a. Outer rotating divergent groove; 5b. Outer circular spiral groove; 6. Diffuser block; 7. Inner pipe column; 8. Piston; 9. Adjustment rod; 10. Rear end cover; 11. Shaft seal; 12. Handwheel. DETAILED DESCRIPTION

[0026] In the following description of the utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inside", "outside" and the like indicate the directions or positional relationships based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not mean that the device must have a specific direction. The part through which the material flow flows first is the "front", and the part through which the material flow flows later is the "rear".

[0027] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below with reference to specific illustrations.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0029] like Figures 1 to 3 As shown, the multi-stage reversing cavitation generator of the utility model comprises a cavitation cylinder 1, a material inlet 1a is arranged at the center of the inlet end of the cavitation cylinder 1, and a swirl generator 3, a contraction block 4, a double-cone vortex generator 5 and a diffuser block 6 are arranged in sequence in the inner cavity of the cavitation cylinder 1 along the material flow direction. The contraction block 4 is provided with a contraction block gradually contracting hole, a contraction block throat and a gradually expanding contraction block center hole along the material flow direction, and the end of the contraction block 4 is provided with a contraction block inner cone surface.

[0030] The swirl generator 3 is in the shape of a spindle with a large middle and small ends. A generator flange 3b is provided at the large diameter in the middle. The generator flange 3b covers the inlet end of the contraction block 4. The tail cone of the swirl generator 3 is inserted into the contraction hole of the contraction block, and multiple cone spiral grooves 3d are evenly arranged on the outer circumference of the cone. Multiple tangential holes 3c are evenly distributed on the circumference of the generator flange 3b and communicate with the inlet end of each cone spiral groove 3d. A large guide cone 3a is provided at the inlet end. The root of the large guide cone 3a is located on the inner side of the circumference of the tangential hole 3c, which evenly guides the inlet material flow to each tangential hole 3c.

[0031] After the tangential holes 3c at the edge of the swirl generator 3 intercept the flow and generate cavitation bubbles, the bubbles are guided into the conical spiral grooves 3d. At the large end of the swirl generator 3, that is, at the entrance of each conical spiral groove 3d, the cross-section is expanded, the flow rate is reduced, the static pressure is increased, the bubbles collapse, and a primary cavitation effect is generated; then the fluid enters the spirally contracting conical channel, and the rotational compression of the fluid is accelerated again in this process. At the same time, with the help of centrifugal action, the materials are fully sheared and mixed.

[0032] After leaving the conical spiral groove 3d, the fluid enters the throat of the contraction block similar to Venturi, and then enters the gradually expanding central hole of the contraction block. The cross-sectional area at the throat of the contraction block is the smallest, and the flow rate reaches the highest. At the same time, cavitation bubbles are generated at the wall boundary under the action of centrifugal force, and then the fluid flows into the double-cone vortex finder 5.

[0033] The middle section of the double-cone vortex finder 5 is cylindrical in circumference, and an outer cone is provided at the inlet and outlet ends respectively. The outer cone at the inlet of the vortex finder fits with the inner cone of the contraction block. The outer wall of the outer cone at the inlet of the vortex finder is evenly provided with a plurality of outward-spinning divergent grooves 5a that divert flow from the center to the periphery, and the outward-spinning divergent grooves 5a extend outward along the vortex line or the involute line.

[0034] The outer cone surface of the vortex finder outlet fits with the inner cone surface of the inlet of the diffuser block 6. The outer wall of the outer cone surface of the vortex finder outlet is evenly provided with multiple inward-turning confluence grooves that converge from the outer periphery to the outlet center hole. The inward-turning confluence grooves extend inward along the vortex line or involute line.

[0035] The outer cylindrical wall of the double-cone vortex finder 5 is provided with a plurality of outer circular spiral grooves 5b, the inlet end of each outer circular spiral groove 5b is connected to the end of the corresponding outer spiral divergent groove 5a, and the end of each outer circular spiral groove 5b is correspondingly connected to the inlet end of the inner spiral converging groove.

[0036] The fluid is forced to rotate and diverge outward along the outward-rotating divergent grooves 5a, and when it reaches the outer wall of the double-cone vortex finder 5, i.e., the inner wall of the cavity of the cavitation cylinder 1, it turns from radial to axial, and flows backward along the outer circular spiral grooves 5b of the double-cone vortex finder 5. When it reaches the rear end surface of the double-cone vortex finder 5, the fluid is forced to rotate and converge from outside to inside again.

[0037] The diffuser block 6 is provided with a diffuser block throat and a diffuser block gradually expanding hole along the material flow direction, and the diffuser block throat is connected to the outlet center hole of the double-cone vortex flow device 5 .

[0038] The fluid path in the rotating groove of the double-cone vortex finder 5 is extended, the cavitation time is the longest, and at the same time, the wall boundary effect of the rotating flow is obvious, the amount of cavitation bubble generation is enhanced, and finally the cross-sectional area of ​​the fluid gradually expands at the diffuser block 6, the flow rate decreases, the static pressure of the fluid increases, and the bubbles collapse, thereby achieving the purpose of strengthening the reaction process.

[0039] The outlet of the gradually expanded hole of the diffuser block is embedded with an inner tube column 7, the end of which is against the center of the rear end cover 10, and the rear end cover 10 covers the rear port of the cavitation cylinder 1. A plurality of radial small holes are evenly arranged on the circumferential wall of the inner tube column 7 to communicate with the outer peripheral space. The end side wall of the cavitation cylinder 1 is provided with a material outlet 1b, and the fluid flows out from the radial small holes on the inner tube column 7 and then flows out from the material outlet 1b.

[0040] The outer peripheral edge of the generator flange 3b is thickened and pressed by the positioning nut 2. The outer thread of the positioning nut 2 is screwed into the inner thread of the cavitation cylinder 1, and the diffuser block 6, the double-cone vortex generator 5, the contraction block 4 and the swirl generator 3 are pressed together.

[0041] A piston 8 is provided in the inner pipe column 7, and the outer periphery of the piston 8 is sealed with the inner wall of the inner pipe column 7 through the piston outer sealing ring. The center of the rear end face of the piston 8 is connected to the adjusting rod 9. The middle section of the adjusting rod 9 passes through the center of the rear end cover 10 and is sealed through the shaft seal 11. The end of the adjusting rod 9 is provided with a threaded section, and the threaded section of the adjusting rod is screwed into the screw hole of the fixing seat. The root of the fixing seat is welded to the outer end face of the rear end cover 10. A hand wheel 12 is installed at the end of the adjusting rod 9. When the hand wheel 12 is turned, the adjusting rod 9 pulls the piston 8 to translate axially, adjusts the distance from the diffuser block 6, and changes the effective length of the inner pipe column 7 and the actual flow area of ​​the radial small hole.

[0042] The above description is only the preferred feasible embodiment of the utility model, which shows and describes the basic principle, main features and advantages of the utility model, but does not limit the scope of patent protection of the utility model. The technicians in this industry should understand that the utility model is not limited by the above embodiments. In addition to the above embodiments, the utility model can also have other implementation modes without departing from the spirit and scope of the utility model. The utility model will also have various changes and improvements. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the utility model. The scope of protection required by the utility model is defined by the attached claims and their equivalents. The technical features not described in the utility model can be achieved by or using existing technologies, which will not be repeated here.

Claims

1. A multi-stage reversing cavitation generator, comprising a cavitation cylinder, a material inlet is arranged at the center of the front end cover of the cavitation cylinder, and a material outlet is arranged on the circumferential wall at the end of the cavitation cylinder, characterized in that: The inner cavity of the cavitation cylinder is provided with: The swirl generator is in the shape of a spindle with a large middle and small ends, and a generator flange is provided at the large diameter in the middle; a plurality of conical spiral grooves are evenly arranged on the outer circumference of the tail cone; a plurality of tangential holes are evenly distributed on the circumference of the generator flange and communicated with the inlet ends of each conical spiral groove; The contraction block is provided with a contraction block gradually contracting hole, a contraction block throat and a gradually expanding contraction block center hole along the material flow direction, and a contraction block inner cone surface is provided at the end; The double-cone vortex flow generator has a cylindrical middle section and outer conical surfaces at both ends. The inlet outer conical surface fits the inner conical surface of the contraction block. A plurality of outward-spinning diverging grooves for diverting from the center to the periphery are evenly arranged on the inlet outer conical surface. A plurality of inward-spinning converging grooves for converging from the periphery to the outlet center hole are evenly arranged on the outlet outer conical surface. A plurality of outer-circular spiral grooves corresponding to the outward-spinning diverging grooves and the inward-spinning converging grooves are arranged on the outer cylindrical wall. The diffuser block is provided with an inner conical surface of the diffuser block, a diffuser block throat and a diffuser block gradually expanding hole along the material flow direction. The inner conical surface of the diffuser block is in contact with the outer conical surface of the outlet of the double-cone vortex finder, and the diffuser block throat is connected with the outlet center hole of the double-cone vortex finder.

2. The multi-stage commutation cavitation generator according to claim 1, characterized in that: An inner tube column is embedded in the outlet of the gradually expanding hole of the diffuser block, and the end of the inner tube column abuts against the center of the rear end cover, and the rear end cover covers the rear port of the cavitation cylinder. A plurality of radial small holes are evenly arranged on the circumferential wall of the inner tube column and communicate with the end inner cavity of the cavitation cylinder.

3. The multi-stage commutation cavitation generator according to claim 2, characterized in that: A piston is provided in the inner pipe column, the center of the rear end face of the piston is connected to the adjusting rod, the middle section of the adjusting rod passes through the center of the rear end cover and is sealed by a shaft seal, the end threaded section of the adjusting rod is screwed into the screw hole of the fixing seat, the root of the fixing seat is fixed on the rear end cover, and a hand wheel is installed at the end of the adjusting rod.

4. The multi-stage commutation cavitation generator according to claim 1, 2 or 3, characterized in that: The outward-turning divergent groove extends outward along the vortex line or the involute line, and the inward-turning converging groove extends inward along the vortex line or the involute line.

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