CN109046792B

CN109046792B - Mixed-flow type microbubble generator and bubble distributor

Info

Publication number: CN109046792B
Application number: CN201811244061.7A
Authority: CN
Inventors: 孙伟; 卫召; 韩海生; 王若林; 胡岳华
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2018-10-24
Filing date: 2018-10-24
Publication date: 2020-09-08
Anticipated expiration: 2038-10-24
Also published as: CN109046792A

Abstract

The invention discloses a mixed-flow type microbubble generator which comprises a contraction pipe, a throat pipe and a diffusion pipe which are sequentially communicated, wherein the output end of the diffusion pipe is in butt joint with an output pipe, the inlet end of the contraction pipe is in butt joint with a closed gas-liquid mixing chamber, a pressure gas inlet pipe and a fluid injection pipe are arranged on the gas-liquid mixing chamber, and spiral blades are arranged in the output pipe. The invention also discloses a bubble distributor comprising the microbubble generator. The invention integrates two methods of forming micro bubbles of a high-pressure dissolved gas separation method and a Venturi tube jet flow foaming method, and further disperses bubbles by using the helical blades, so that a large number of micro bubbles with the diameter of 0.1-0.3mm can be formed, the formed bubbles have the characteristics of small bubble size and uniform dispersion, the adjustment of the bubble diameter can be realized by replacing helical blades with different specifications, and the invention has the advantages of high working stability, difficult nozzle blockage and the like.

Description

Mixed-flow type microbubble generator and bubble distributor

Technical Field

The invention belongs to the technical field of flotation of mining equipment, and particularly relates to a mixed flow type microbubble generator and a bubble distributor.

Background

Flotation is an important way for recovering valuable minerals in non-ferrous metal ores, and compared with other flotation equipment, the flotation column has the advantages of high enrichment ratio, simplicity in equipment installation and maintenance, easiness in production process control and the like, particularly has obvious advantages in sorting of fine ore particles, and is gradually developed into main flotation equipment of the non-ferrous metal ores. Bubbles are an indispensable key factor for froth flotation, and an effective bubble generation device should be able to generate fine and uniform bubbles at the maximum possible aeration rate. Therefore, the study of bubble generators in flotation columns is one of the most important aspects of the study of flotation columns.

The flotation column bubble generator is divided into an internal foamer and an external foamer according to the bubble generation mode. The internal foamers are commonly a vertical pipe foamer, a filter disc type foamer, a gravel bed layer foamer and the like, but the foamers are easy to scale and block in production, so that a flotation column cannot normally operate, and the internal foamer is rarely adopted at present, and the external micro-bubble generator replaces the internal micro-bubble generator in a large amount to become a mainstream. The foaming method adopted by the external bubble generator generally comprises an electrolysis method, a pressure dissolution method, a mechanical bubble induction method and the like, and the external bubble generator solves the problem that the foaming device is easy to block and is widely applied in industry. The static mixer can absorb air automatically, has large inflation quantity, can manually adjust the size of bubbles, does not block and does not need to be cleaned, but has more complex structure and high requirement on the processing precision of an internal structure; the cyclone type bubble generator is not easy to block, when the bubble generator works, the liquid level of the flotation column is relatively stable, when the flotation column does not work, redundant ore pulp does not need to be discharged, but the bubbles of the bubble generator are not uniformly distributed and are accompanied with segregation phenomenon; the diameter of bubbles generated by the self-suction microbubble generator is small, but the requirement for introducing gas is high, and the work is not stable enough.

The chinese invention patent 201610467816.4 discloses an electrolytic micro-bubble generator for fine material flotation. However, the above-mentioned microbubble generator adopts electrolytic foaming, the cost of electrolytic foaming is high, the service life of the electrode is limited, the cost of replacing the electrode is also high, and the oxygen and hydrogen generated by electrolysis belong to extremely combustible gas, and there is a great potential safety hazard in the using process! The generated bubbles comprise hydrogen, oxygen and general air bubbles, and the three bubbles have different densities, so the adhesion force to particles in the mineral flotation process is different, and the flotation of mineral particles is influenced to a certain extent.

Disclosure of Invention

The present application is directed to solving at least one of the problems in the prior art. Therefore, an object of the present invention is to provide a mixed-flow microbubble generator and a bubble distributor, which can form microbubbles with small bubble size and uniform dispersion and have high operation stability.

In order to solve the technical problems, the invention adopts the following technical scheme:

the mixed-flow type microbubble generator comprises a contraction pipe, a throat pipe and a diffusion pipe which are communicated in sequence, wherein the output end of the diffusion pipe is in butt joint with an output pipe, the inlet end of the contraction pipe is in butt joint with a closed gas-liquid mixing chamber, a pressure gas inlet pipe and a fluid injection pipe are arranged on the gas-liquid mixing chamber, and spiral blades are arranged in the output pipe.

Furthermore, the axis of the fluid injection pipe is overlapped with the axis of the throat pipe, and the fluid injection pipe and the air inlet pipe are arranged at an included angle.

Furthermore, the included angle is 40-45 degrees.

Furthermore, the cone angle of the contraction pipe is 30-35 degrees.

Furthermore, the cone angle of the diffusion pipe is 35-40 degrees.

Further, the longitudinal length ratio of the contraction pipe, the throat pipe and the diffusion pipe is 1:4: 2.

Furthermore, the nozzle of the fluid jet pipe is a conical nozzle with a cone angle of 15-20 degrees.

A bubble distributor comprises at least two annular air distribution pipes which are concentrically arranged and communicated through connecting pipes and a plurality of mixed-flow type microbubble generators, wherein air outlets are uniformly distributed on the pipe wall of each annular air distribution pipe, and air inlets which are communicated with output pipes in a one-to-one correspondence mode are symmetrically arranged on the annular air distribution pipe positioned on the outermost layer.

Furthermore, the adjacent annular gas distribution pipes are communicated through a plurality of connecting pipes which are positioned between the adjacent annular gas distribution pipes and are annularly and uniformly distributed.

Compared with the prior art, the invention has the following beneficial effects:

1. the method integrates two methods of forming the micro bubble by a high-pressure dissolved gas separation method and a Venturi tube jet flow foaming method, the formed micro bubble has the advantages of small bubble size, uniform dispersion, simple structure, high working stability, difficult blockage of a nozzle and the like, and a foaming agent can be added into water flow.

2. The helical blades arranged in the output pipe can further break up bubbles to form a large number of micro-bubbles with the diameter of 0.1-0.3mm, and the diameter of the bubbles can be adjusted by replacing helical blades with different specifications.

3. The bubble distributor can uniformly and stably distribute mixed flow microbubbles in the flotation column body, and is favorable for efficiently mineralizing bubbles and minerals in flotation equipment.

Drawings

FIG. 1 is a schematic diagram of a mixed-flow microbubble generator according to the present invention;

fig. 2 is a schematic diagram of the structure of the bubble distributor installed on the flotation column.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the mixed flow type microbubble generator comprises a pipe body 1, wherein the pipe body 1 comprises a contraction pipe 5, a throat pipe 6 and a diffusion pipe 7 which are sequentially communicated, an outlet of the diffusion pipe 7 is connected with an output pipe 9, an inlet of the contraction pipe 5 is directly communicated with a closed gas-liquid mixing chamber 4, and a pressurized gas inlet pipe 2 and a fluid injection pipe 3 are arranged on the gas-liquid mixing chamber 4.

The operation of the microbubble generator is as follows: fluid sprayed at high speed from a fluid spraying pipe 3 is introduced into a gas-liquid mixing chamber 4, so that negative pressure is formed in the gas-liquid mixing chamber 4, high-pressure air flow is sprayed into the gas-liquid mixing chamber 4 through an air inlet pipe 2, the gas is dissolved into a large amount of water body due to the huge pressure difference between the negative pressure generated by high-speed movement of water flow and the high-pressure gas, the water flow is gradually converted into kinetic energy at a contraction pipe 5 due to the reduction of the cross section of the pipe body, the flow speed is accelerated, gas and liquid phases form strong turbulent kinetic energy at the contraction pipe, the gas is sheared, torn and mixed by the turbulent flow to form a large amount of small-diameter bubbles, the bubbles are further mixed in a throat pipe 6, the fluid and the gas generate violent mass and energy exchange, the energy transfer process of a gas-liquid dispersion medium is completed at the outlet of the throat pipe 6, the gas and liquid phases carry out, the cross section of the diffusion pipe is suddenly increased to reduce the flow speed, the kinetic energy of the gas-liquid mixed flow is gradually converted into pressure energy, bubbles are further dispersed into micro-bubbles with smaller diameter, and meanwhile, the dissolved gas in the water body is further dissolved out to form a large number of micro-bubbles in the diffusion pipe.

The embodiment integrates a high-pressure dissolved gas separation method and a venturi tube jet foaming method, the formed bubbles have the characteristics of small bubble size and uniform dispersion, the adjustment of the bubble diameter can be realized by adjusting the water pressure and the air pressure and replacing spiral cutters with different specifications, and the device has the advantages of high working stability, difficulty in blocking a nozzle and the like. Compared with the traditional venturi tube which dissolves gas by self-absorption, the negative pressure generated by the high-speed movement of water flow and the high-pressure gas have huge pressure difference, the gas is dissolved into the water body in a large amount, the dissolved gas can be separated out in a large amount in the diffusion tube, and in addition, the foaming agent is added into the high-pressure water source to further increase the bubble effect.

The mixed-flow microbubble generator provided by the embodiment of the invention is provided with the helical blade in the output pipe, and the helical blade is detachably arranged in the output pipe and is coaxial with the output pipe. The ratio of the major diameter to the minor diameter of the helical blade is 2:1, the lead angle of the helical blade is 25-30 degrees, and the pitch of the helical blade is 5-10 mm. The gas-liquid mixed flow can automatically rotate along the spiral direction through the spiral blades to form a rotating turbulent flow, the turbulent flow further shears the bubbles to further refine the bubbles, the size of the bubbles is stabilized at 0.1-0.3mm, and the diameter of the bubbles can be adjusted by replacing the spiral blades with different specifications.

Specifically, the axis of the fluid jet pipe 3 coincides with the axis of the throat pipe 6, and a flow field which is uniformly and stably distributed can be generated in the contraction pipe 5, the throat pipe 6 and the diffusion pipe 7 through the arrangement, so that on one hand, stable acting force can be formed on gas, bubbles with more uniform diameter distribution can be obtained, on the other hand, friction between the fluid and the pipe wall when the fluid passes through the throat pipe can be reduced, the energy loss along the way can be reduced, and the energy conversion efficiency can be improved.

Preferably, the jet direction of the fluid jet pipe 3 intersects with the jet direction of the air inlet pipe 2 and forms a certain included angle, and the included angle is preferably 40-45 degrees. The air inlet pipe 2 and the central axis of the throat pipe form a certain included angle, so that the transverse flow rate of the gas can be increased, the collision shearing acting force of turbulence and the gas can be increased at the contraction pipe, and the dispersion of the gas is facilitated.

Preferably, the vertical cross-sections of the convergent tube 5 and the divergent tube are tapered to further narrow the bubbles. The taper angle of the contraction pipe 5 is 30-35 degrees, the taper angle of the diffusion pipe 7 is 35-40 degrees, the longitudinal length ratio of the contraction pipe 5 to the throat pipe 6 to the longitudinal length ratio of the diffusion pipe 7 is 1:4:2, the nozzle of the fluid jet pipe 3 is a taper nozzle with a taper angle of 15-20 degrees, the output pipe 8 is a pipeline with the same diameter, the inner diameter of the output pipe is equal to that of the outlet of the diffusion pipe 7, and the size of the bubbles can be further refined through the arrangement.

Referring to fig. 2, a bubble distributor comprises at least two annular air distribution pipes 11 concentrically arranged and communicated with each other through a connecting pipe 10, and a plurality of mixed-flow type microbubble generators, wherein air outlets are uniformly distributed on the pipe wall of each annular air distribution pipe 11, and air inlets (not shown in the figure) communicated with the output pipes 9 in a one-to-one correspondence manner are annularly and symmetrically arranged on the annular air distribution pipe 11 at the outermost layer.

Specifically, the implementation adopts two annular air distribution pipes 11, the diameter ratio of the two annular air distribution pipes 11 is 1:2, the connecting pipes 10 are uniformly distributed in an annular space between the two annular air distribution pipes, the annular air distribution pipe 11 at the outermost layer is provided with four air inlets, and each air inlet is butted with one bubble distributor. In practical application, the bubble distributor is preferentially considered to be applied to a flotation column, the annular gas distribution pipe is arranged in the flotation column, 4 mixed-flow type micro-bubble generators are arranged on the side wall of a flotation column body 12 and are communicated with gas inlets on the annular gas distribution pipe, pressurized water flow enters from a fluid injection pipe of the mixed-flow type micro-bubble generator, pressurized air enters from a gas inlet pipe of the mixed-flow type micro-bubble generator, a large amount of micro-bubbles are formed at the diffusion pipe, the bubbles enter the annular gas distribution pipe through the gas inlets and are sprayed out through gas outlet holes in the annular gas distribution pipe, and rising bubbles which are uniformly and stably distributed are formed in the flotation column body.

The above examples are merely illustrative for clearly illustrating the present invention and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Nor is it intended to be exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the scope of the invention.

Claims

1. A bubble distributor, characterized in that: comprises at least two annular gas distribution pipes which are concentrically arranged and communicated with each other through a connecting pipe and a mixed-flow type microbubble generator;

the mixed-flow type microbubble generator comprises a contraction pipe, a throat pipe and a diffusion pipe which are sequentially communicated, wherein the output end of the diffusion pipe is in butt joint with an output pipe, the inlet end of the contraction pipe is in butt joint with a closed gas-liquid mixing chamber, a pressure gas inlet pipe and a fluid injection pipe are arranged on the gas-liquid mixing chamber, and a spiral blade is arranged in the output pipe;

the axis of the fluid injection pipe is overlapped with the axis of the throat pipe, and the fluid injection pipe and the air inlet pipe are arranged at an included angle of 40-45 degrees;

air outlets are uniformly distributed on the pipe wall of each annular air distribution pipe, and air inlets which are communicated with the output pipes in a one-to-one correspondence mode are annularly arranged on the annular air distribution pipe positioned on the outermost layer;

the nozzle of the fluid jet pipe is a conical nozzle with a cone angle of 15-20 degrees;

the cone angle of the contraction pipe is 30-35 degrees;

the cone angle of the diffusion tube is 35-40 degrees;

the longitudinal length ratio of the contraction pipe to the throat pipe to the diffusion pipe is 1:4: 2;

the adjacent annular gas distribution pipes are communicated through a plurality of connecting pipes which are positioned between the adjacent annular gas distribution pipes and are annularly and uniformly distributed.