RU2596570C2 - Liquid-vapor plasmatron - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention refers to liquid-vapor plasmatron. On a metal tubular case there is a fixed reservoir for working fluid, filled with moisture absorbing material. Nozzle-confuser is held on the front part of the tubular body with a detachable cap with the help of threaded connection. There is coaxially movable central electrode and electric discharge chamber inside the housing. Cylindrical head front part of the aforementioned evaporator has an annular projection in the form of a shank with through longitudinal slots. There is covering it from the outside an elastic element that spring-loads the evaporator, this element rests into the inner annular projection of the housing on one side, and it rests into projection of the head part of the evaporator on the other side, and an insert that made from a set of rings made of capillary-porous material. Electrode with clearance relative to the evaporator is fixed coaxially in the head part of the metal rod holder, a tail rear part of it is installed with possibility of longitudinal movement in regulating and centering electrode mechanism. There is a drain tube inside the housing, one end of the tube is located near the shank of the evaporator, and the other end is in the rear part of the reservoir near its fuel filler. Cylindrical outer diameter of shank of the evaporator is smaller than outer diameter of the head part of the evaporator, which simplifies its manufacturing and assembly of the plasmatron. Elastic element is made from a set of heat-resistant plate springs.

EFFECT: technical result is in improving reliability and increasing service life of the plasmatron.

1 cl, 1 dwg

Description

The invention relates to small-sized devices for producing a plasma jet (plasmatrons) from vapors of a working fluid and can be used in various industries, construction, housing and communal services, for producing nanodispersed materials, in particular nanodiamonds (according to the invention according to the patent RU 2844014).

Known electric arc plasma torch (RU 2040124), cooled by vapor of the working fluid, containing coaxially mounted output nozzle-anode and a central rod cathode. The cathode is attached to a holder covered by a cylinder of heat-conducting material, on which a tube of porous material is worn. The tube is in contact with a moisture-absorbing material placed in a reservoir for the working fluid. The cathode holder is mounted with the possibility of axial movement and is equipped with a mechanism for such movement, allowing to close the cathode and anode to excite the arc, and to change their relative position for smooth power changes.

Known electric small-sized plasmatron (RU 93720) with a reservoir for a plasma-forming liquid filled with capillary-porous moisture-absorbing material. The process of vaporization in it is carried out due to the heat released on the working electrodes at given values of the arc currents of indirect or indirect and direct action. The change in pressure in the plasmatron is carried out discretely, by setting nozzles forming a plasma jet with different diameters of the working holes and / or by setting different values of the arc currents.

Known coaxial plasmatron containing coaxially placed a tubular electrode, a nozzle with an axial through hole, a removable central electrode located in the rod holder of the electrode coaxially inside the tubular electrode and with a gap relative to it and nozzle with the possibility of the formation of a discharge chamber and with the possibility of axial reciprocating translational movement, the mechanism of contact excitation of the electric arc between the nozzle and the central electrode, made in the form of a discontinuous ektricheskogo contact mechanism comprising axially displaceable rod-shaped electrode having a pair of helical, spring and button device for vaporization and delivery into the discharge chamber plasma-forming medium in the form of vapor of the working fluid. The plasma torch contains a reservoir with a nozzle for supplying this fluid, filled with moisture-absorbing material to ensure its contact with the tubular electrode, a vortex stabilization device for the electric arc, a nozzle and electrode cooling device, an electrode centering mechanism relative to the nozzle through-hole, down conductors for electrical connection of terminals of an independent electric current source and a protective casing (RU 2278328, 05/13/2005).

The disadvantages of the above analogues are due to low reliability, and are also related to the fact that the pressure of the plasma-forming vapors inside the plasma torch, which determines the main parameters of the plasma jet, is unstable and smoothly increases as the fluid flows and the details of the plasma torch warm up, depending on the initial temperature of the charged working fluid, temperature the environment and the intensity of the plasma torch. During the operation of the plasma torch, the pressure also depends on the initial temperature of the plasma forming unit of the plasma torch, the uneven distribution of pressure inside the reservoir with the working fluid, the quality of heat transfer from the nozzle to the evaporator, depending on the state of the mating surfaces, the degree of wear of the cathode. The consequence of these drawbacks is a long time for reaching the operating mode due to the thermal inertia of the plasma torch, the instability of the plasma jet, uneven evaporation of the components of the plasma-forming liquid, as well as the possible interruption of the arc in welding mode when working on a mixture in the form of a multicomponent working fluid.

These drawbacks were eliminated by introducing additional parts and devices into the plasma torch design that allow stabilizing and / or controlling the pressure in the plasma forming unit, as well as reducing the plasma torch operating time, especially at low ambient temperatures (RU 99678, November 20, 2010).

The technical result of this analogue is achieved by the fact that the steam-liquid plasmatron contains a movable central electrode and a nozzle-confuser arranged coaxially in the housing, which acts as a second electrode, providing the formation of an electric discharge chamber, a device for vaporization of the working fluid (evaporator), a reservoir with moisture-absorbing material for the fluid, and a mechanism centering the rod electrode relative to the nozzle. This plasma torch also includes a cylindrical body located parallel or at an acute angle to the elongated part of the L-shaped reservoir, holding the nozzle cap, attached to the body, adjacent to the nozzle tube evaporator with tangential openings in its tail section, which has the form of a truncated cone with expansion towards the cylindrical head part, and with a central channel for supplying working fluid vapors to the electric discharge chamber, inside which the central electrode is located, is fixed null in the head of the movable rod holder, the tail of which is installed in a ballast and centering electrode mechanism. In addition, the plasma torch comprises a coil compression coil covering the outside of the evaporator cone and a composite tubular insert made of a set of rings made of capillary-porous material, the insert being in contact with the material filling the reservoir.

The disadvantages of this analogue are connected with the fact that the pressure of the plasma-forming vapors inside the plasma torch, which determines the main parameters of the plasma jet, is unstable and depends on the operating conditions of the plasma torch. This is due to unstable vaporization due to insufficient free and uniform penetration of liquid into the evaporator and due to pressure drops inside the plasma torch. The disadvantages include overheating of the compression coil springs and the nozzle-confuser, which complicate the maintenance of the plasma torch.

A known vapor-liquid arc plasma torch (RU 115141, 04/20/2012 - prototype), which includes a movable central electrode and a nozzle-confuser placed coaxially in its cylindrical body, forming an electric discharge chamber, a reservoir for a working vapor-generating liquid filled with a moisture-absorbing material, holding a removable cap holding the nozzle-confuser adjacent to the nozzle-confuser tubular evaporator with a cylindrical head (front) and opposite tail (rear) conical parts and with a Central channel for supply liquid vapor into the electric discharge chamber, while the conical part of the evaporator covers the outside of the liner made of a set of rings made of capillary-porous material, the liner in contact with the material of the tank, and the electrode coaxially with a gap relative to the evaporator is fixed in the head (front) part of the rod holder , the tail (rear) part of which is installed with the possibility of movement in the ballast and centering electrode mechanism. In the cone (rear) part of the evaporator, through longitudinal grooves are made, which provide more free and uniform penetration of liquid from the insert into the evaporator. Inside the plasma torch there is a drainage tube equalizing the pressure. One end of it is located in the housing near the rear end of the evaporator, and the other end is in the tank near the filler neck.

The disadvantages of the prototype are the complexity of manufacture and maintenance, low reliability and the maximum achievable current in the arc due to insufficient heat removal through the junction of the nozzle and the evaporator, as a result there is overheating ("subsidence") of the twisted compression spring, pressing the front end of the evaporator to the nozzle.

The technical result of the proposed technical solution is to increase the reliability, the operating current in the arc and increase the life of the plasma torch as part of the Gorynych plasma complex (TU 3441-002-56754389-2008).

The specified technical result is achieved in that the vapor-liquid plasmatron includes a metal tubular body, with a reservoir for the working fluid fixed therein filled with moisture-absorbing material, and a copper nozzle-confuser, which is held on the front of the tubular body by a removable cap using a threaded connection. A coaxially movable central electrode, an electric discharge chamber formed by the front of the electrode and the internal cavity of the nozzle-confuser, adjacent to it by the front end, axially spring-loaded for heat removal, are fitted with a tubular copper evaporator with a cylindrical head (front) part, which has an annular ledge before its continuation in the form of a shank with through longitudinal grooves, on which are placed an elastic element covering it from the outside, a spring-loaded evaporator and abutting with one side to the inner annular protrusion of the housing, and on the other hand, to the ledge of the head of the evaporator, and an insert made of a set of rings made of capillary-porous material that contacts the moisture-absorbing material of the tank, while the electrode is coaxially fixed with a gap relative to the evaporator in the head (front) part of the metal rod holder, the tail (rear) part of which is installed with the possibility of longitudinal movement in the ballast and centering electrode mechanism, akreplennom plasmatron at the rear of the housing. Inside it there is a drainage tube, one end of which is located in the housing near the shank of the evaporator, and the other end is in the rear of the tank near its filling neck. Unlike the prototype, the shank of the evaporator is cylindrical, its outer diameter is smaller than the outer diameter of the head of the evaporator, which simplifies its manufacture and subsequent assembly of the plasma torch. The elastic element is made of a set of heat-resistant disk springs, which significantly increase the force of pressing the end face of the evaporator to the nozzle with the provision of heat removal, compared with the prototype sufficient to increase the current in the arc without overheating of the plasma torch parts.

Figure 1 shows the front of the plasma torch and separately the evaporator according to the technical solution, where

1 - housing

2 - cap

3 - nozzle-confuser,

4 - a central electrode,

5 - rod holder

6 - evaporator

7 - place of installation of the temperature sensor,

8 - elastic element.

The plasmatron operates as follows.

The working fluid is fed into the reservoir, soaking it with moisture-absorbing material, the liner, and filling the channels connecting the reservoir to the discharge chamber. Starting current is supplied to the down conductors by a starting voltage. Close the end of the electrode to the inner surface of the nozzle until a short contact occurs. The necessary breaking of the electrical contact by means of springs between the electrode and the nozzle excites an electric arc. The thermal energy released by the arc is transmitted through the evaporator to the working fluid in the liner. It turns into steam, creating excess pressure, under which steam is supplied through the grooves to the discharge chamber, stabilizes the arc in the axial region, overheats and enters the shaped channel of the nozzle in the form of a confuser. Under the action of arc energy, geometrically compressed by the nozzle walls, it passes into the plasma state in the vapor channel with the formation of a plasma jet at the exit from the nozzle, which is used for thermal plasma processing of products using known methods and techniques. To control the arc current and control the temperature of the plasma torch parts in order to avoid overheating and violation of the processing mode, a programmable power supply and plasmatron control unit with an integrated stabilized current regulator are used as in analogues. Thus, the main parameters of the plasma jet are controlled (nozzle outflow rate, temperature distribution in the jet, jet shape), including their stability, providing high quality and wide technical capabilities of heat treatment in accordance with the invention, including the possibility of generating a plasma jet in water. The operation of the plasma torch is described in more detail in the “Operating Instructions” of the Gorynych plasma complex (http://as-pp.ru).

Example 1 (surface treatment of materials with heating by a plasma jet formed by a duty arc of indirect action and combined with a direct-acting arc excited between the plasma torch and the product). Perform all the operations described above. Then, voltage is applied to the nozzle and the electrically conductive article being processed by the known methods from the power supply unit and the plasmatron control unit and a potential difference is created between them. Then, the distance between the nozzle and the product is reduced to the appearance of a direct-acting arc combined with a plasma jet, and processing is performed. For example, by adjusting the above basic parameters of a plasma jet and direct-acting arc, plasma welding is carried out using known methods and techniques.

Example 2. Obtaining nanodiamonds.

The finely dispersed diamond phase of carbon in the form of an aqueous suspension (diamond nanoparticles) in accordance with the invention RU 2484014 is obtained using a plasma complex of the Gorynych type (RU 93720 U1, 05/10/2010) using an 80% ethanol solution as a plasma forming working medium distilled water. A plasma jet is introduced into water by immersing a plasma torch nozzle in it. The presence of a finely dispersed diamond allotropic form of carbon in water is recorded by its bluish-bluish luminescent glow characteristic of diamond when illuminated by a UV light source (see the description of patent RU 2484014). In this case, the current I = 12 A and voltage U = 90-180 V are set on the control panel of the plasma torch. The sizes of nanodiamonds are 20-30 nm.

The proposed technical solution is industrially applicable and, taking into account the achieved technical result, it will be used to complete the Gorynych plasma complex (TU 3441-002-56754389-2008), as well as a device for producing nanodispersed materials, such as nanodiamonds.

Claims (1)

A vapor-liquid plasma torch containing a metal tubular body, a reservoir for the working fluid fixed on it, filled with moisture-absorbing material, and a copper nozzle-confuser, which is held on the front of the tubular body by a removable cap using a threaded connection, a movable central electrode, an electric discharge chamber are coaxially placed inside the body formed by the front of the electrode and the internal cavity of the nozzle-confuser, adjacent to it by the front end, spring-loaded in the axial direction and a heat-conducting tubular copper evaporator with a cylindrical front part and an annular ledge made in the form of a shank with through longitudinal grooves, on which are placed an elastic element covering the outside for springing the evaporator, resting on one side against the inner annular protrusion of the housing, and on the other hand, against ledge of the head of the evaporator, and the liner made of a set of rings made of a capillary-porous material that is in contact with moisture-absorbing material, while the trod coaxially with a gap relative to the evaporator is fixed in the head front of the metal rod holder, the rear rear of which is mounted with the possibility of longitudinal movement in the ballast and centering electrode mechanism, mounted in the rear of the plasma torch body, inside which there is a drainage tube, one end of which is located in the body near the shank of the evaporator, and the other end in the rear of the tank near its filling neck, characterized in that the shank the evaporator is cylindrical with an outer diameter smaller than the outer diameter of the head front of the evaporator, and the elastic element is made of a set of heat-resistant cup springs.

Images