RU229442U1 - Plasma torch for cutting metal - Google Patents

Abstract

The utility model relates to a device for high-temperature cutting of metal using a plasma arc. The technical result of the claimed utility model is to ensure the possibility of cutting metal with high cut quality in a short time. The plasma torch for cutting metal contains a head, an air cylindrical tube, a cathode, an air diffuser, a nozzle, a protective attachment, an attachment for creating a compressed air flow and focusing the plasma arc, and a compression nut. 20 fig.

Description

The utility model relates to a device for high-temperature cutting of metal using a plasma arc.

The prior art includes a design for a plasma torch that contains a housing with an electrode and a nozzle placed in it, the inner surface of which is made in the form of a cone that transitions into a cylinder at the outlet of the nozzle (see US patent 2862099 for invention, published 11/25/1958).

The disadvantage of the known plasma torch design is its low service life due to insufficient cooling of the housing.

A plasma torch is known from the prior art (see USSR Author's Certificate No. 1798085 for invention, published on 28.02.93), comprising a rectangular section housing, an electrode unit connected through an insulator to a nozzle unit by fastening elements located on different sides of the electrode unit, wherein the fastening elements are made with elastic sections, and their nozzle axes are located in the longitudinal plane of symmetry of the plasma torch, in particular, the elastic sections of the fastening elements are made in the form of rubber hoses.

The disadvantage of the known plasma torch is the complexity of the design due to the use of a water cooling system.

A plasma torch is known from the prior art, containing a housing with a nozzle in which an electrode is mounted (see USSR Author's Certificate No. 437586 for invention, published on 30.07.1974).

The disadvantage of the known plasma torch is its low reliability.

A plasma torch for cutting metals is known from the prior art, comprising a housing with an electrode installed in it in the form of a toroid, a nozzle, a main and additional swirl bushings with tangential channels for supplying plasma-forming gas (see USSR Author's Certificate No. 645798 for invention, published 02/05/1979).

The well-known plasma torch also has low operational reliability.

The purpose of the claimed utility model is to create a plasma torch with a compact and lightweight design for manual and mechanized cutting of metal, in which, when electric current flows through the discharge gap, a plasma arc column is formed, used for processing metals or as a source of light and heat.

The technical result of the claimed utility model is to ensure the ability to cut metal along any cutting path with high quality in a short time.

The technical result of the claimed utility model is achieved by the fact that the plasma torch is made in the form of a single structure containing:

- plasma torch head;

- an air cylindrical tube installed in the plasma torch head and having four inlets for supplying air from the plasma torch head into the internal cavity of the cathode for cooling it;

- a cathode having a cylindrical shape of variable diameter with an internal recess for placing an air cylindrical tube and internal thread for screwing onto the plasma torch head through an air diffuser, on the outer end of the cathode in the center there is a recess for placing a hafnium insert, on the outer surface of the cathode along the circumference there are four flat areas in the form of a cone for ease of screwing onto the plasma torch head;

- an air diffuser for creating a directed air flow, screwed in a spiral, cooling the cathode and compressing the plasma arc, having a cylindrical hollow shape with two sides on the ends for installation on the head of the plasma torch on one side and installation of a nozzle on the other side, on the side surface of the air diffuser along the circumference there are two rows of through holes, offset relative to each other by 20 degrees for swirling the air, which enters the plasma-forming channel to increase the stability of the plasma arc;

- a nozzle for focusing a plasma arc, having a hollow cylindrical shape at one end, which transitions into a hollow truncated cone shape at the other end, while at the top of the truncated cone there is a through hole for the plasma to exit, and at the other cylindrical end there is a protrusion for installation on the side of the air diffuser;

- a protective attachment for fixing and protecting the internal nozzle, cathode and air diffuser from mechanical damage, consisting of a shell in the form of a cylindrical sleeve with an external part in the form of a truncated cone, on one of the external end surfaces of which there is a thread for fixing a compression nut, and on the other external end surface a ring is pressed to improve the manufacturability of the assembly, reduce the amount of defects when pressing in the cup, while the sleeve has an internal cup with variable diameters of the internal walls with a thread on one side and a shelf with holes on the other side;

- a nozzle for creating a compressed air flow and focusing a plasma arc, having a hollow cylindrical shape at one end, turning into a hollow truncated cone shape at the other end, wherein on the outer end surface of the cylindrical shape of the nozzle there is a step for pressing with a compression nut to the protective nozzle, on the beveled surface of the nozzle there is a series of through holes equidistant from each other around the circumference for the outlet of air, and at the top of the truncated cone there is a through hole for the outlet of air and plasma;

- a compression nut of cylindrical shape, on the inner surface of which there is a flange for pressing the nozzle to create a compressed air flow and focus the plasma arc to the protective nozzle and a thread for fixing on the protective nozzle, and on the outer surface there is a cylindrical knurling for ease of manual tightening on the protective nozzle.

The features and essence of the claimed utility model are explained in the following detailed description, illustrated by drawings, which show the following.

Figure 1 shows the design of the claimed plasma torch.

Figure 2 shows the design of the plasma torch in assembly (sectional view)

Figure 3 shows the operation of the plasma torch when gas is supplied.

Figure 4 shows a variant of the cathode implementation with the geometric dimensions of its parts.

Figures 5 and 6 show two variants of the implementation of contact nozzles with geometric dimensions of the nozzle parts.

Figures 7-9 show three variants of the implementation of contactless nozzles with geometric dimensions of the nozzle parts.

Figures 10-13 show four variants of nozzle implementation.

Figure 14 shows a variant of the implementation of an air diffuser.

Figure 15 shows the design of the plasma torch head (implementation option).

Figure 16 shows the design of the plasma torch head (implementation option, sectional view).

Figures 17 and 18 show two variants of the protective attachment.

Figure 19 shows an embodiment of a compression nut.

Figure 20 shows an embodiment of an air tube.

In figures 1-20, the following is indicated under the same positions:

1 - plasma torch head;

2 - nozzle;

3 - protective nozzle;

4 - contact/non-contact nozzle;

5 - cathode;

6 - air diffuser;

7 - air tube;

8 - compression nut;

9 - hafnium insert;

10 - recess for placing the air tube;

11 - recess for placing the hafnium insert;

12 - flat areas on the outer surface of the cathode;

13 - hollow cylindrical shape of the nozzle;

14 - a hollow form in the form of a truncated cone of the nozzle;

15 - step for pressing;

16 - a row of through holes in the nozzle for air outlet;

17 - through hole of the nozzle for air and plasma outlet;

18 - hollow cylindrical nozzle shape;

19 - a hollow shape in the form of a truncated cone of the nozzle;

20 - through hole for plasma outlet;

21 - protrusion for installing the nozzle on the side of the air diffuser;

22 - hollow cylindrical shape of air diffuser;

23 - two sides of the air diffuser;

24 - two parallel rows of through holes around the circumference of the air diffuser;

25 - cylindrical shape of the compression nut;

26 - flange of the compression nut;

27 - samples of the air cylindrical tube;

28 - protective nozzle shell;

29 - protective nozzle ring;

30 - protective nozzle insert;

31 - outer part of the protective nozzle sleeve in the form of a truncated cone.

The plasma torch (see figures 1-3) contains a plasma torch head 1, a nozzle 2, a protective attachment 3, an attachment 4 for creating a compressed air flow and focusing the plasma arc, a cathode 5, an air diffuser 6, an air tube 7, a compression nut 8 and a hafnium insert 9.

Cathode 5 (see Fig. 4) has a cylindrical shape of variable diameter. Inside cathode 5 there is a recess 10 for placing air tube 7 and G1/8 thread for screwing onto head 1 of plasma torch through air diffuser 6. For convenience of screwing onto head 1 of plasma torch, cathode 5 has four flat platforms 12 in the form of a cone on the outer surface. On the outer end there is a recess 11 for a hafnium insert. Cathode 5 is made of copper grade M3. Dimensions of cathode 22.25x11.9x11.9 mm. Weight 0.01 kg.

Cathode 5 conducts electric current and maintains continuous arc burning. The pilot arc is excited between the nozzle and the cathode, in the process turning into the main plasma-forming arc.

Figures 5-9 show variants of implementing nozzles 4 for creating a compressed air flow and focusing the plasma arc.

In embodiments, the plasma torch may have, for example, contact nozzles 4 (see Figures 5 and 6) or contactless nozzles 4 (see Figures 7-9).

Contact nozzle 4 creates an optimal distance between the plasma torch and the product being cut during contact cutting.

Nozzle 4 contactless is used for the mechanized version of the plasma torch.

The nozzles 4 have a cylindrical shape 13 in one part and a truncated cone shape 14 in the other part. On the outer surface there is a step 15 for pressing with a clamping nut 8 to the protective nozzle 3. On the beveled surface 14 there are twelve holes 16 with a diameter of 1 mm for air outlet. At the end there is a hole 17 of different diameters for air and plasma outlet. The nozzles 4 are made of copper grade MZ. The dimensions of the nozzles are 16.8 x 21.8 x 21.8 mm. Weight 0.01 kg.

Figures 10-13 show four variants of implementing the plasma torch nozzle 2 with different geometric dimensions of their parts.

Nozzles 2 are designed to focus the plasma arc and have a cylindrical shape 18 in one part and a truncated cone shape 19 in the other part. At the end of the nozzles there is an opening 20 for the plasma outlet. At the other end there is a flange 21 for installation on the air diffuser 6. Nozzles 2 are made of copper grade M3. Weight 0.01-0.02 kg.

Air diffuser 6 (see Fig. 14) is designed to create a directed air flow, screwed in a spiral, cooling the cathode and compressing the plasma arc.

The air diffuser 6 has a cylindrical shape 22 with two flanges 23 on the ends for installation on the head 1 of the plasma torch on one side and installation of the nozzle 2 on the other side. On the side surface along the circumference there are two parallel rows of holes 24 with a diameter of 1 mm, shifted relative to each other by 20 degrees. The dimensions of the diffuser 6 are 10.8 x 18 x 18 mm. The diffuser 6 is made of plastic.

Figures 15 and 16 show the design of the head 1 of the plasma torch.

The head 1 of the plasma torch is an assembly unit used to supply gas for plasma formation and consists of a housing, an assembly nozzle, an insulator, a cover, a rod, a spring, a supply tube, an air tube, a union nut, a stop, a locking ring, a screw, two wires, two pins and a locking washer.

The insulator is installed on the body, then the rod is installed in the body, after which a stop is installed on the back side of the rod. Then the assembly nozzle is installed on the insulator and fixed on it with a pin. A spring is placed on the stop and compressed by the cover, after which a pin is installed in the rod, a locking ring is installed in a special groove, the wire tip is screwed to the end using a lock washer and a screw. The air tube 7 is inserted with force until it stops in the rod. There is also a G1/8 thread on the rod for fixing the cathode 5 on it. An insulator with a flange is glued to the end side of the assembly nozzle, onto which the air diffuser 6 is installed.

Figure 17 shows a variant of the implementation of protective attachment 3 of a 100-120 A plasma torch.

Figure 18 shows a variant of the implementation of protective attachment 3 of a 40-80 A plasma torch.

Protective attachment 3 (see figures 17 and 18) is designed to secure and protect the internal parts of the plasma torch from mechanical damage - nozzle 2, cathode 5, air diffuser 6.

The protective attachment 3 consists of three parts: a shell 28, an insert 30, and a ring 29. The shell 28 is a ceramic cylindrical sleeve with a part in the shape of a truncated cone 31. On one of the end surfaces there is a G3/4 thread. On the other side, a brass ring 29 is pressed onto the sleeve. A brass cup with variable internal diameters is pressed into the sleeve, having a G3/4 thread on one side and a shelf with holes with a diameter of 0.5 mm on the other side. The dimensions of the protective attachment are 39.6 x 35 x 35 mm. Attachment 3 is made of ceramics and brass. Weight is 0.06 kg.

Figure 19 shows an embodiment of the compression nut 8.

The compression nut 8 has a cylindrical shape 25. On the inner surface there is a flange 26 for pressing the nozzle 4 contact/contactless to the protective nozzle 3 and a G3/4 thread for fixing on the protective nozzle 3. On the outer surface there is a cylindrical knurling for easy tightening in manual mode.

Figure 20 shows an embodiment of the air tube 7.

Air tube 7 is designed to supply air to the internal cavity of cathode 5 for its cooling. Air tube 7 is made of stainless steel. At the ends it has four recesses 27 for air to exit from head 1 of the plasma torch. The dimensions of the tube are 32x4.5x4.5 mm. Tube 7 is made of steel.

The operating principle of the plasma torch is as follows (see figures 2 and 3).

When the plasma-forming gas is supplied to the head 1 of the plasma torch, pressure is generated in the internal circuit, the air pressure breaks the connection of the cathode 5 and the nozzle 2, the plasma-forming gas enters the zone of the hafnium insert 9 on the cathode 5 and is ionized, then the plasma exits through the opening 20 in the nozzle 2 and is compressed by the external circuit of the gas duct, consisting of the contact/contactless nozzle 4 and the nozzle 2.

In the absence of a supply of plasma-forming gas to the head 1 of the plasma torch, the cathode 5 and nozzle 2 form a tight connection and the plasma-forming gas does not enter the zone of the hafnium insert 9 on the cathode 5.

The declared plasma torch, due to its design features, has the following advantages:

1. Cooling of the cathode 5 by plasma-forming gas occurs from both sides, which significantly increases its service life.

2. The plasma torch is easily disassemblable, which allows replacing the structural elements (components) included in the plasma torch without resorting to the use of any special tools.

3. The design of the plasma torch does not involve the formation of galvanic pairs, which eliminates the occurrence of corrosion.

4. All structural elements (components) included in the plasma torch are designed in such a way that the costs of their manufacture are not high.

5. The design of the plasma torch allows for use both in manual mode and with the use of special roller attachments.

6. Air diffuser 6 is designed in such a way that the plasma-forming gas, entering the internal circuit, forms a vortex directed towards the exit, which increases the stability of the plasma arc combustion.

7. Nozzles 4 have a hole 17 on the end, as well as holes 16 on the angular (conical) surface at an angle of 90 degrees to it, which allows not only to crimp the plasma arc, but also to cool the adjacent metal surface, which reduces the temperature effect on it.

8. The holes 16 on the beveled surface of the nozzle 4 create an air screen, which allows protecting the plasma torch and surrounding surfaces from the effects of metal cutting products.

The process of assembling the plasma torch is carried out as follows (see Fig. 1).

An air tube 7 is installed in head 1 of the plasma torch, then an air diffuser 6 is installed on head 1 by insertion, and cathode 5 with hafnium insert 9 is screwed through air diffuser 6. Next, nozzle 2 is installed by insertion into protective attachment 3, after which this subassembly is screwed onto head 1 of the plasma torch, covering cathode 5 and air diffuser 6. Then contact or contactless attachment 4 is placed on protective attachment 3, after which pressure nut 8 is screwed onto protective attachment 3.

When designing the plasma torch, the diameters of the nozzles 2 and the attachments 4 were selected in such a way that the cutting size was minimal due to the aerodynamic and thermodynamic effect, and also to minimize the likelihood of a cascade arc, the number of holes 16 and their diameter in the attachments 4 were selected in such a way as to cool the surrounding metal surface as much as possible to preserve its strength properties.

The declared plasma torch has a compact and lightweight design. The plasma torch is easy to disassemble and assemble.

The design of the plasma torch at the operating pressure of the plasma-forming gas allows for maximum compression of the plasma arc and ensures the removal of molten metal, which in turn ensures high quality cutting.

The conducted analysis of the state of the art allowed us to establish that there are no analogues with a set of essential features identical to the essential features of the claimed plasma torch, which indicates that the claimed plasma torch complies with the patentability condition of “novelty”.

Although the claimed utility model has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and content may be made therein without departing from the essence and scope of the utility model, which are defined by the appended claims of the utility model, taking into account the description and drawings.

Claims (8)

Plasma torch for cutting metal, containing: - head; - an air cylindrical tube installed in the plasma torch head and having four inlets for supplying air from the plasma torch head into the internal cavity of the cathode for cooling it; - a cylindrical cathode with a variable diameter, in the inner recess of which an air cylindrical tube is placed, and in the center of the end in the recess a hafnium insert is placed, while the cathode is connected by means of an internal thread to the head of the plasma torch through an air diffuser, and on the outer surface of the cathode there are four flat cone-shaped platforms located around the circumference at the same distance from each other for ease of screwing onto the head of the plasma torch; - an air diffuser having a cylindrical hollow shape with two sides at the ends, installed on the head of the plasma torch on one side, on the other side of which a nozzle is mounted, while on the side surface of the air diffuser along the circumference there are two rows of through holes, offset relative to each other by 20 degrees; - a hollow nozzle, having a cylindrical shape at one end, turning into a truncated cone at the other end, while at the top of the truncated cone there is a through hole for the plasma to exit, and at the other cylindrical end there is a protrusion, with the help of which the nozzle is mounted on the side of the air diffuser; - a protective fixing attachment for protecting the nozzle, cathode and air diffuser located inside it from mechanical damage, which is a shell in the form of a cylindrical sleeve with an external part in the form of a truncated cone, while on one external end surface of the attachment there is a thread for fixing with a compression nut, and on the other external end surface a ring is pressed, while the sleeve has an internal cup with variable diameters of internal walls with a thread on one side and a shelf with holes on the other side; - a hollow nozzle for creating a compressed air flow and focusing a plasma arc, having a cylindrical shape at one end, turning into a truncated cone shape at the other end, at the apex of which there is a through hole for the outlet of air and plasma, wherein on the outer end surface of the cylindrical nozzle there is a step, by means of which it is pressed by a compression nut to a protective nozzle, and on the beveled surface of the nozzle there is a row of through holes around the circumference for the outlet of air, located at the same distance from each other, wherein the compression nut has a cylindrical shape, on its inner surface there is a flange for pressing the said hollow nozzle to the said protective nozzle and a thread fixing the nut on the protective nozzle, and on the outer surface there is a cylindrical knurling for ease of manual tightening on the protective nozzle.