Method of preparation of magnetically conductive powders by cavitation and device to carry out the method

Abstract

A method of preparing magnetically conductive powders based on principle of liquid flow control in a cavitation line, where in a jet tube are evoked, during the rise of a cavitation cloud and implosion of cavitation bubbles with intensity up to ultrasound frequency 24 kHz, pulse shock waves acting on a surface of a substance whereby are released particles in dimensions in range of micrometer or nanometer units. Particles of the substance from a jet tube are carried away by liquid media into a header where they are captured via a magnetic element. A device includes a cavitation line that is equipped for capture of decavitated particles of the substance by at least one header along which is placed a magnetic element.

Claims

1. A method of preparing magnetically conductive powders based on principle of liquid flow control in a cavitation line comprising evoking, in a jet tube during the rise of a cavitation cloud and implosion of cavitation bubbles with intensity up to ultrasound frequency 24 kHz, pulse shock waves acting on a surface of a substance which is fixed to the jet tube, to thereby release particles, of the substance including one or more of microparticles or nanoparticles, wherein the particles of the substance are carried away from the jet tube by liquid media into a header where they are captured via magnetic element.

2. The method according to claim 1, further comprising regulating, by a pump, speed of the liquid in the cavitation line and the position of cavitation cloud in the jet tube where the cavitation on the surface of the substance acts with the highest intensity.

3. The method according to claim 1, wherein decavitated particles of the substance are selectively captured by virtue of the lay out or division of a magnetic field created by acting of the magnetic element.

4. The method according to claim 1, wherein the substance is mounted to the jet tube.

5. The method according to claim 1, wherein the substance is mounted to the jet tube by at least one screw.

6. The method according to claim 1, wherein the substance is mounted to the jet tube by at least one mounting member.

7. The method according to claim 1, wherein the substance is attached to the jet tube at at least two locations on the substance.

Description

DESCRIPTION OF FIGURES IN ENCLOSED DRAWINGS

(1) Particular examples of an invention design are simplified illustrated in enclosed drawings, where

(2) FIG. 1 is a basic scheme of cavitation device with basic components pro preparation of metal powders,

(3) FIG. 2 is an extended scheme of cavitation device with basic and support components,

(4) FIG. 3 is a lengthwise and vertical cut of cavitation jet tube in the place of cavitated substance storage,

(5) FIG. 4 is a lengthwise and vertical cut of header with variable placing of magnetic system,

(6) FIG. 5 is a microscopic picture of the structure of agglomerated nano powder Fe with dimensions in micrometers range,

(7) FIG. 6 is a microscopic picture of the structure of non-agglomerated nano powder Fe in dimensions in range smaller than 300 nanometers,

(8) FIG. 7 is an alternative design of cavitation device with three level parallel setting of cavitation jet tubes and

(9) FIG. 8 is a lengthwise cut of alternative design of header and magnetic system.

(10) The drawings which illustrate featured invention and consequently described examples of particular design do not in any case limit extend of the protection mentioned in definition, but only clarify essence of the solution.

EXAMPLES OF TECHNICAL SOLUTION DESIGN

(11) The device for preparation of metal powders in basic design according to FIG. 1 consists of a cavitation line 1 realized in the form of closed circuit, whereof are series way built in components, namely a tank 2 for a liquid, pump 3, stop valve 4, cavitation jet tube 5 and header 7, where these components are mutually interconnected directly or by the help of connecting pipeline 11 and a cavitation chamber 52 is modified for storage of cavitated substance 6.

(12) An alternative design of the device is schematically illustrated in FIG. 2 where is into the cavitation line 1 built in monitoring system 9 and a control unit 10, whereas to the control unit 10 is connected not only the monitoring system 9 but also even particular control components built in into the cavitation line 1, namely the tank 2, pump 3, stop valve 4, cavitation jet tube 5 and magnetic element 8. In advantageous design the tank 2 is equipped with a cooling system 21 and the pump 3 is equipped with a frequency changer 31. The monitoring system itself 9 contains a feedback surface sensor 91 and a thermal sensor 92 which are placed on the tank 2 and its parts are also a pressure gauge set 93 for monitoring the pressure in the liquid. The pressure gauge set 93 contains two pressure sensors 931 situated in cavitation line 1 on the suction of the pump 3 and on the pump 3 displacement and two pressure readers 932 which are placed directly in the cavitation chamber 52 and in diffuser 53 of the jet tube 5. Likewise is the monitoring system 9 equipped with a feedback comparing thermal detector 94 and a flowmeter 95 for measurement of the speed, of the liquid entering the jet tube 5. Further part of the monitoring system 9 is a scanning unit 96 of liquid media acceleration, which is situated directly in the jet tube 5.

(13) The cavitation jet tube 5 is illustrated in FIG. 3 and consists of several parts which are tied together, when the intake part is formed by a confusor 51 in the shape of a truncated cone, central part by a cylindrical cavitation chamber 52 and discharge part by a diffuser 53 also in the shape of a truncated cone, whereas in the cavitation chamber 52 is firmly settled a cavitated substance 6 in the form of differently shaped magnetically conductive volume material, when the mounting is in exemplary design realized via at least one screw.

(14) On the diffuser 53 of the jet tube 5 concurs a header 7 around which is from the outer side, around perimeter placed a magnetic element 8, whereas the header 7 is realized in the form of a shaped header tube 71 which has on its input and output shape of a truncated cone and in the central part shape of cylinder with bigger crosscut than is the crosscut of the connecting pipe 11 in the space behind the cavitation jet tube 5. The magnetic element 8 itself is either formed by a permanent magnet 81 or consists of a permanent magnet 81 and electromagnet 82. The magnetic element 8 is placed along outer wall of header tube 71 of the header 7, namely either around its whole outer perimeter or only in the part of its outer surface as is clear from FIG. 4.

(15) The preparation of a metal powder in the basic device design proceeds in the way that in the cavitation line 1 is liquid pumped from the tank 2 by the pump 3 into the jet tube 5 where the liquid media goes at first through confusor 51 by which action comes to a significant rise of the liquid speed and simultaneously to decrease of the pressure, namely under the pressure of saturated vapours, whereby in liquid occur first cavitation bubbles which proceed at a very high speed into the cavitation chamber 52. In the space of cavitation chamber 52 where is settled the substance 6 comes to arise of a cavitation cloud and implosion of cavitation bubbles, whereby in the liquid is evoked formation of pulse shock waves acting on the surface of the substance 6. As a result of action of dynamic compression stress, evoked by implosion of cavities in liquid media, on the substance 6 release particles 61 of magnetically conductive materials. The liquid then flows form cavitation chamber 52 into the diffuser 53 where comes to decrease of liquid's speed and gradual expiration of cavitation. Form the diffuser 53 is the liquid led directly into the header 7 where comes to capture of decavitated particles 61 of the substance 6. Very separation of the particles 61 of decavitated substance 6 is enabled thanks to flowing liquid speed reduction in the header tube 71 of the header 7 and by acting of a magnetic field which is emitted by magnetic member 8 where on inner wall of header tube 71 comes to capture of decavitated particles 61 of the substance 6. From the header 7 is by the help of connecting pipe 11 the liquid led back into the tank 2.

(16) In an alternative design the preparation of metal powder proceeds in the way that by the help of monitoring system 9 are monitored and regulated parameters of flowing media, whereas monitoring system 9 and also particular components 2, 3, 4, 5 and 8 which influence cavitation process are connected to a control unit 10, which evaluates, sets and controls process of metal powder production. By the help of a cooling system 21 of the tank 2 comes to liquid cooling, whereas is also controlled replenishment of the liquid or release of the liquid from the tank 2. A pressure reader 932 serves to information record about intensity and position of the collapse of bubbles of cavitation cloud in cavitation chamber 52 and diffuser 53, whereby is enabled efficient control of pump 3 performance and change of position of a cavitation cloud in the jet tube 5.

(17) A scanning unit 96 of liquid media acceleration enables record of vibrations when monitors vibrations in defined axe of Cartesian system, thus at least at entry into the jet tube 5, in the place of intensive cavitation and at output in front of the header 7. To very control of lengthwise shift of a cavitation effect on the surface of the substance 6 and for intensity setting of evoked cavitation in the jet tube 5 serves a frequency changer 31 of the pump 3, whereas by the help of pressure sensors 931 is monitored pressure in the liquid of inlet and displacement of the pump 3. The permanent magnet 81 of the magnetic element 8 then serves in the case of electromagnet 82 plug in into the technology system as a slave unit whose function is to prevent loss of powder production at electric current black out and prevention of possible contamination of cavitation system.

(18) Decavitated particles 61 of the substance 6 captured in the header 7 can be in two states, namely in the form of decavitated nano-powder with dimension in micrometer unit range as is illustrated in FIG. 5 or directly in the form of non-agglomerated particles of the nano-powder with dimension smaller than 300 nanometers as is perceptible from FIG. 6. By lay out or division of a magnetic field of magnetic element 8 is enabled a selective capture of decavitated particles 61 of the substance 6, namely without the presence of liquid or with permanent presence of the liquid where is in highly reactive materials possible to prevent undesired reaction with surrounding environment, for example oxidation.

(19) Described setting of cavitation line 1 realized in the form of one circuit pipe system is not the only possible design of the invention. As is illustrated in FIG. 7 the connecting pipe 11 of the cavitation line 1 can be realized in three parallel set pipe shoulders 111 where each pipe shoulder 111 is equipped with independent stop valve 4, jet tube 5, header 7 and magnetic element 8. The number of this way connected pipe shoulders 111 of the cavitation line 1 is not limited. Further the magnetic element 8 can emit magnetic field with constant intensity or intensity relative in the direction of flow from the weakest to the strongest. The permanent magnets 81 and/or electromagnets 82 are placed on the outer side of the header tube 71 of the header 7, whereas they can be placed also inside around whole inner diameter of the header 7 and can be realized as divided ones and be placed either in the lower part of the header 7, where flows the liquid, and/or in upper part where on the contrary liquid does not flow. In an alternative design can be for example magnetic element 8 formed by protective polymer film coated on inner wall of the header tube 71 of the header 7. The crosscut of connecting pipe 11 of the cavitation line 1 or header tube 71 of the header 7 can have circular, elliptical, rectangular, polygonal, figurate, irregular or mutually combined shape, whereas the header 7 is formed by header tube 71 with the same or bigger crosscut then is the crosscut of the connecting pipe 11 of the cavitation line 1 in the space behind jet tube 5 as is evident form FIG. 8. The examples of substance 6 mounting in the jet tube 5 and its shape clarify only essence of the mounting with the screws, however the mounting can be done also in another way for example with groove, weld, slid-in mechanism, by the help of glue and so on.

(20) The way of preparation of magnetically conductive powders according to the invention is based on principle of the control of liquid flow in cavitation line 1 where is evoked cavitation acting on surface of inserted substance 6. Efficient evocation and action of the cavitation is realized in jet tube 5 in whose work cavitation chamber 52 is partly settled the substance 6 and partly comes to rise of cavitation cloud and implosion of cavitation bubbles with intensity up to ultrasound frequency 24 kHz, whereby is evoked rise of dynamic compression stress acting on surface of the substance 6. By the help of the pump 3 is possible to regulate speed of the liquid in cavitation line 1 whereby is in the lengthwise direction controlled shift of the place where the cavitation on the surface of the substance 6 acts with highest intensity. From decavitated surface of the substance 6 are released ultra fine particles 61 in dimension of nanometers or micrometers unit range. These particles 61 of the substance 6 are from the jet tube 5 carried away by the liquid media into the header 7, where comes to their separation form the liquid flowing further in closed system. The very separation of decavitated particles 61 of the substance 6 is enabled via reduction of the speed of flowing liquid at interaction of magnetic field emitted from magnetic element 8 where on the inner wall of the header 7 comes to capture of decavitated particles 61 of the substance 6. By suitable lay out or division of magnetic field of magnetic element 8 is enabled selective capture of decavitated particles 61 of the substance 6 for example in upper part of the header tube 71 which is in surrounding atmosphere already without presence of flowing liquid or in the lower part of the cavitation chamber 52 which is in permanent contact with flowing liquid and in highly reactive materials can be this way avoided undesired reaction with surrounding environment.

INDUSTRIAL UTILITY

(21) Featured invention belongs to area of powder metallurgy and production of metal powders with nanometric or micrometric size of individual particles, whereas especially use of the nano-materials is much extended with possibility of exercise in many different industrial branches as is healthcare, engineering, civil engineering, chemical industry, textile industry or electro-technical industry.

LIST OF REFERENCE NUMERALS

(22) 1 cavitation line 11 connection pipe 111 pipe shoulder 2 tank 21 cooling system 3 pump 31 frequency changer 4 stop valve 5 jet tube 51 confusor 52 cavitation chamber 53 diffuser 6 substance 61 particles 7 header 71 header tube 8 magnetic element 81 permanent magnet 82 electromagnet 9 monitoring system 91 surface sensor 92 thermal sensor 93 pressure gauge set 931 pressure sensor 932 pressure reader 94 regulation thermal detector 95 flowmeter 96 scanning unit 10 control unit