SU1680463A1 - Plasma burner - Google Patents

Abstract

The invention relates to the plasma treatment of electrically conductive materials and can be used for plasma mainly point welding of ferrous and non-ferrous metals. The purpose of the invention is to reduce the transverse dimensions of the burner and increase its operational reliability. For this, the burner housing 7 and the electric holder with manifold 9 are combined into a non-separable assembly using a compound 10 insulator 10 filled in or pressed between them. The burner cooling system, made in one channel, is enclosed inside fixed knot. The water-cooled cavities of the housing 7 and the collector 9 are interconnected by tubes 11 of a dielectric material located in the compound insulator 10 along the axis of the burner 3 or

Description

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The invention relates to the plasma treatment of electrically conductive materials and can be used for plasma, mainly spot, welding of ferrous and non-ferrous metals.

The purpose of the invention is to reduce the transverse dimensions of the burner and increase its operational reliability.

FIG. 1 shows a burner, a longitudinal section; in fig. 2 shows section A-A in FIG. one; in fig. 3 shows a section BB in FIG. one.

The burner contains a non-separable unit with insulator 2, plasma-forming nozzle 3, protective nozzle 4 and copper-tungsten electrode insert 5 installed with a captive nut 1 and installed with a threaded joint with a seal 6. Disassembled assembly of the burner consists of body 7 with fitting 8 for supplying protective gas and electrode holder with collector 9, separated by an insulator 10 from a compound in which a cavity for the electrode holder and parallel to the axis of the burner are made channels for the passage of cooling liquid STI

The channels are formed by tubes 11 of a dielectric material attached to sleeves 12 and 13.

The electrode holder includes a coaxially arranged inner tube 14 with a fitting for connection to the water cooling line and an outer tube 15 mated with a protective sleeve 16. forming a coolant passage cavity between them Outer tube 15 has a thread for connecting the electrode insert 5, channels 17 on the side surface, made straight on the narrow part of the tube and in the form of multiple pass 00

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a wide helical groove in its wide part and a hole 18 for water to flow from the electrode holder to the collector 9. The cavity has two cavities 19 and 20, each of which is connected to the cooling cavity 21 of the housing 7 by several channels. The number of channels depends on the flow area of the tube 14, which is determined from the burner cooling conditions. The cavity 20 through the nozzle 22 is connected to the main line for cooling water removal. In the lower part of the collector 9 there is a chamber 23 for plasma-forming gas, connected by a channel 24 with the nozzle 25. The outer surface of the insulator 2 and the inner surface of the housing 7 together form the chamber 26 for protective gas. In the plasma-forming nozzle 3, the edges of the axial center channel are provided with channels 27 for the passage of protective gas from the chamber 26 into the gap between the plasma-forming nozzle 3 and the protective nozzle 4. In the body of the electrode insert 5, grooves are provided for gripping with a special key.

The burner works as follows.

Initially, a shielding gas, a plasma-forming gas and water are supplied to the burner. Plasma-forming gas from chamber 23 through channels 17 enters the cavity between electrode insert 5 and plasma-forming nozzle 3. As it passes through the screw grooves in the lower part of tube 15, the gas flow twists. a standby arc between the inner wall of the plasma-forming nozzle 3 and the electrode insert 5. A rotating plasma-forming gas stream carries a stand-by arc through the central channel of the plasma-forming nozzle 3, forming a plasma jet at the channel exit. When the plasma jet touches the product, the plasma-forming nozzle 3 is disconnected from the source, the working plasma arc is automatically excited between the electrode and the product.

The protective gas, filling the chamber 26, passes through the channels 27 into the gap between the plasma-forming and protective nozzles, preventing the arc from moving from one nozzle to another, and additionally stabilizes the plasma jet. Due to the passage of gas through the channels 27, the plasma-forming nozzle 3 is further cooled.

The water entering the burner through the tube 14 cools the electrode insert 5, rises up the gap between the tubes 14 and 15 and flows out through the hole 18 into the cavity

19 of the collector 9. From the cavity 19 through the channels formed in the isolator from compound 10 by tubes 11, the cooling fluid enters the cavity 21 of the housing 7, then through the channels in the isolator from the compound into the cavity 20 of the collector 9 and through nozzle 22 goes to the main plum. Due to the heat sink from the burner body 7, the plasma-forming nozzle 3 indirectly cools

0 its contact with the body surface. Direct cooling of the electrode insert and indirect cooling of the plasma-forming nozzle is sufficient to prevent their thermal overload during

5, predominantly spot welding, alternating current and direct current of direct and reverse polarity, since in this case the period of switching on the arc is 30-40%.

0 To replace the electrode insert 5, the cap nut 1 is unscrewed, the protective nozzle 4 and the plasma-forming nozzle 3 are removed. The electrode insert is unscrewed and screwed in using a special

5 keys.

In comparison with the prototype, the application of the invention allows to improve the operational reliability of the burner by eliminating the sealing seals in the cooling system; 2-3 times increase the service life of the burner due to the absence in the non-separable assembly of parts that can fail due to violation of the operating conditions of the burner

5 (the remaining parts of the device are interchangeable); reduce the burner diameter due to the insulator thickness between the casing and the electric holder.

Performance test layout

0 plasma torch with an outer diameter of 28 mm and a length of 90 mm showed the reliability of its operation, the high resistance of a non-melting electrode with a diameter of 2–5 mm and a plasma-forming nozzle with a diameter

5 central channel 2–4 mm when welding with alternating current and direct current of direct and reverse polarity up to 300 A at a duty cycle of 30%, coolant flow rate 3–6 l / min, plasma gas flow rate 1–3 l / min and shielding gas 3-9 l / min.

Claims (1)

The invention claims: A plasma torch comprising an insulated body and an electrode holder with 5 interconnected cooling cavities, a nozzle fixed on the body, an insulator, a collector with a cooling cavity, as well as fittings for supplying and discharging water, characterized in that, in order to reduce the transverse dimensions of the burner and increase its operational reliability, the housing, the electrode holder and the collector are inseparably connected by an insulator, the insulator is made with a cavity for the electrode holder and channels for the cooling medium parallel to the axis of the burner, the collector is installed on the non-working end of the burner, and I pagt 4U fll t its cavity is connected to the cooling cavity of the housing through one of the insulator channels and to the fitting for draining water, and the cooling cavity of the electrode holder is connected to the fitting for water supply and to the cooling cavity of the housing through the collector cavity and the second insulator channel. 13 fig 2 sixteen 74 25 24 23 fig.d