CH625977A5 - Detonation coating installation - Google Patents

Abstract

The installation has an explosion space (1) having at least one spark plug (4) and a metering device (3) for the coating material. The metering device (3) contains a container (10), which is connected by a channel (11) to a mixing chamber (9), as well as a device for controlling the cross-sectional area of the channel (11). This device has a separating wall (18) which consists of gas-permeable material, bounds an annular cavity (19) for connection to a compressed-gas source and is arranged in the container (10), equidistant from its walls (15). A non-return valve (26) is arranged in the channel (11) at its connection point to the container (10). Such an installation ensures cyclic metering of the coating material powder into the explosion space, and reliable protection of the assemblies of the installation against the influence of the increased pressures and temperatures in the event of a blowback from the explosion space. The installation can be used for applying coatings consisting of finely dispersed powders of materials composed of compounds having high melting points, such as tungsten, chromium and molybdenum carbides. <IMAGE>

Description

The present invention relates to a detonation coating system with an explosion chamber, which is designed in the form of a tube closed at one end with at least one spark plug arranged therein, with a chamber for processing the explosion mixture, with a doser for the coating material in the form of powder, with a Mixing chamber is connected, wherein the doser has a bunker which is connected to the mixing chamber by a channel, with a device for regulating the cross-sectional area of the channel and with a nozzle for inevitably supplying the coating material into the explosion space.

Such systems are used to atomize coating powder with the combustion products of an explosion mixture.

The present system can be used for the application of coatings from finely dispersed powder of materials made of melting compounds, such as tungsten, chromium and molybdenum carbides.

In known systems of the type mentioned, the explosion space is designed in the form of a calibrated cylinder tube, the length and diameter of which are selected as a function of conditions, the fulfillment of which is necessary to excite and propagate a detonation wave generated in the explosion space by blasting the explosion mixture. The detonation wave has a high pressure and a high temperature and propagates at a maximum speed which is constant for the given explosive and the prevailing conditions and which reaches 2 to 4 km / s.

The chamber for processing the explosion mixture contains valves in its walls for supplying components of the explosion mixture, such as fuel gas, oxidizing agent and neutral blowing gas, into its mixing cavity.

The system has an electronic control unit.

At a command from the control unit, the valves of the chamber for processing the explosion mixture open in a specific order, and this in the mixing cavity

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The explosion mixture created in this chamber is fed to the explosion chamber, to which the coating material powder is simultaneously fed from the mixing chamber of the doser. Then the chamber is blown through to prepare the explosion mixture with neutral gas, and the explosion mixture is blown up in the explosion space with the aid of the spark plug.

As a result of the detonation of the explosive mixture, a high pressure and a high temperature occur in the explosion space and there is a rapid development of explosion gases which are in a highly compressed state at the moment of the detonation and which are physical agents during their implementation the instant one Transition from the positional energy of the explosion mixture to the kinetic energy of the mobile gases takes place.

This energy is transferred to the powder particles of the coating material suspended in the gas stream, causing them to heat up, their movement increases in speed, and these particles form a coating on the surface of the workpiece arranged in front of the explosion chamber when they emerge from the open end of the explosion chamber out.

The main disadvantage of this detonation coating system is that, using highly finely dispersed powdered coating materials, it self-seals in the bunker, which causes an uneven supply of the powder to the mixing chamber of the doser and further to the explosion space. This interferes with the cyclical supply of the coating material powder and thus the coating quality as a whole is worse.

The disadvantages of the known system also include the fact that the backward shock waves accompanying the detonation propagate in all directions due to the specific nature of the detonation coating process, and additional constructive and technological measures to protect the components of the system and the coating material powder require the influence of increased pressures and temperatures in case of setbacks.

Operating experience with the known systems has shown that the main focus for increasing their work accuracy and producing high-quality homogeneous coatings is also on agents which ensure the cyclical supply of a dose of coating material powder to a strictly specified section of the explosion space, and on measures which ensure a full mixing of the Secure the explosion mixture with the coating material powder, ie it must be directed it is necessary that its particles are distributed evenly in the flow of the explosion products and occupy a minimal, compact section of the length of the explosion space.

The purpose of the present invention is to eliminate the disadvantages mentioned.

The invention has for its object to provide a detonation coating system with such a constructive solution to their assemblies, which cyclic dosing of the coating material powder in the explosion space and reliable protection of the assemblies of the system against the effects of increased pressures and temperatures in the event of a detonation of the detonation wave guarantees the explosion space, which can improve the coating quality as a whole and ensure reliable operation of the system.

This object is achieved according to the invention in the installation of the type mentioned at the outset as defined in the characterizing part of claim 1.

This solution will make it possible to eliminate the self-sealing of the coating material powder in the bunker and in particular the finely disperse powder, because the coating material powder appears to "bulge" under the influence of the compressed gas entering the cavity of the bunker through the gas-permeable partition wall, which makes its free passage to the channel of the Dosators and further to its mixing chamber facilitated, which increases the safety of the cyclical dosing of the coating material powder and thus its quality is improved.

In addition, the arrangement of a check valve at its connection point with the bunker in the channel of the doser protects against the intrusion of the explosion wave in the event of setbacks from the explosion space.

This is particularly important when using finely dispersed powders as coatings that can be easily thrown out of the bunker with the explosion wave.

Taken together, it will make the work of the plant more precise, more productive and more profitable.

The invention is explained in more detail below with reference to the accompanying drawings; it shows:

1 shows a schematic representation of an overall view of the first variant of the detonation coating system according to the invention,

2 shows a longitudinal section through the location “A” in FIG. 1 (on a larger scale),

3 shows an overall view of the detonation coating system according to the invention in the second variant,

4 shows a section along line IV-IV in FIG. 3.

The detonation coating system contains the explosion room 1 (FIG. 1), a chamber 2 for processing the explosion mixture and a doser 3 for coating material powder, which are connected to the explosion room 1.

The explosion chamber 1 is designed in the form of a calibrated cylinder tube which is closed at one end and in which a spark plug 4 is arranged at this point. The explosion chamber 1 is connected to the chamber 2 for processing the explosion mixture via a protective tube 5 designed as a coil and a safety valve 6.

The coating material powder dispenser 3 has the housing 8 (FIG. 2) with a mixing chamber 9 and a channel 11, which connects these to a bunker 10.

In the first variant (FIG. 1) of the detonation coating system, the mixing chamber 9 of the doser 3 is arranged coaxially with the explosion chamber 1 and connected to it via a feed pipe 12, the corresponding end of which is in an axial through-hole made on the end face of the closed end of the explosion chamber 1 is arranged.

The blasting nozzle 13 (FIG. 2) for forcibly conveying the coating material powder “B” into the explosion space 1 is arranged coaxially in the mixing chamber 9 of the doser 3.

The longitudinal channel 14 of the nozzle 13 communicates with a source (not shown) of compressed gas which conveys the powder.

The walls 15 of the bunker 10 have the shape of a truncated cone narrowing downwards and merge into the bottom 16 thereof. The bunker 10 is closed from above with a lid 17 which has an opening for filling the bunker 10 with powder “B”.

According to the invention, a partition 18 made of gas-permeable material, which forms an annular cavity 19 connected to the compressed gas source, is arranged equidistantly from its walls 15 in the bunker 10.

In addition, a tube 20 of gas-permeable material is arranged coaxially therewith in the bunker 10, the upper end of which can be read through the opening in the cover 17 of the bunker 10

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sen and is connected to the pressurized gas source, while the lower end is supported on a conical projection 21 formed on the bottom 16 of the bunker 10 and has openings 22 for gas flow into the cavity of the bunker 10 which are evenly distributed on the circumference of the tube 20. The axes of these openings 22 are directed at the same angle to the bottom 16 of the bunker 10.

As an air-permeable material for the partition wall 18 and the tube 20, metal ceramics or any other material (for example felt, metal net, nettle) can be used, the porosity of which for free ventilation of the gas from the annular cavity 19 and the interior of the tube 20 into the cavity of the bunker 10 is sufficient.

The air-permeable material, of course, must not let even the most finely dispersed coating material powder “B” pass out of the cavity of the bunker 10.

The ventilation of the gas into the cavity of the bunker 10 through the gas-permeable partition wall 18 and the walls of the tube 20 will allow the self-sealing of powders, in particular finely dispersed powders on the walls of the bunker 10 and to prevent their free passage into the channel 11 of the To ensure Dosators 3.

In the housing 8 of the doser 3, at the connection point of the channel 11 and the bunker 10, a transverse parting joint is made, which is formed by two flanges 23 and 24 connected together on the circumference by means of screws 25.

In the channel 11 of the housing 8 of the doser 3, a check valve is arranged at its junction with the bunker 10, which blocks the channel 11 in the event of a kickback from the explosion space 1.

A non-return valve serves as a check valve, which is arranged in the above-mentioned joint between the flanges 23 and 24 and has a through-bore 27 coaxial with the channel 11, which connects the channel 11 to the cavity under the floor 16 of the bunker 10. In the bottom 16 of the bunker, through holes are provided on its periphery for the passage of the coating material powder into the channel 11. A conical projection 28, which serves as a check valve seat and which covers the opening 27 in the membrane 26 during its deflection during the check, is formed on the bottom 16 opposite the opening 27 in the membrane 26.

A device for regulating the cross-sectional area of this channel 11 is arranged in the channel 11 of the housing 8 of the doser 3.

This device contains an elastic tube 29 arranged in the channel 11 and a nozzle 30 as well as an electromagnetic valve 31 covering the channel 11, which are accommodated on both sides of the tube 29.

The powder cans are regulated by the nozzle 30, which is arranged coaxially with the spindle 32 of the electromagnetic valve 31 in a threaded through hole in the housing 8 of the doser 3 and is secured with a screw nut 38.

By turning the nozzle 30, the gap between it and the spindle 32 of the electromagnetic valve 31 and thus the cross section of the elastic tube 29 in which the coating material powder “B” moves from the bunker 10 into the mixing chamber 9 of the meter 3 can be changed .

The chamber 2 (FIG. 1) for the preparation of the explosion mixture is connected via electromagnetic valves 34, 35 and 36, which are arranged in supply lines 37, 38 and 39, to sources of explosion mixture components (not shown).

In the present system, valve 34 connects chamber 2 to a source of oxidant (oxygen), valve 35 to a source of neutral gas (nitrogen), and fuel (acetylene) is supplied via valve 36.

In addition to the actuators mentioned, the system contains a high-voltage generator 40 which gives pulses to the spark plug 4, with the aid of which the explosion mixture is ignited.

In the second variant of the detonation coating system shown in FIG. 3, the length of the explosion chamber 1 is made up of two telescopically connected parts 41 and 42, of which the tail end 41 (on the right in FIG. 3) of the explosion chamber 1 is and is an outer part partially surrounds the second inner part 42, an inner cavity 43 being formed between them.

The second part 42 of the explosion space 1 ends with a jet nozzle 44 which is arranged in the cavity 43 mentioned. In addition, the spark plug 4 is attached in the second part 42 not far from the closed end of the explosion space 1.

The junction of the above-mentioned parts 41 and 42 of the explosion space 1 is enclosed from the outside with an annular jacket 45, which has a cavity with the tail end 41

46 forms that with the cavity 43, in which the jet nozzle 44 is located, and with the mixing chamber 9 (FIG. 2) of the doser

3 communicates.

The cavity 46 of the jacket 45 is connected to the cavity 43, in which the jet nozzle 44 is arranged, via channels 47 (FIGS. 3 and 4) which are formed in the walls of the tail end 41 of the explosion space 1 and are evenly distributed over its circumference. The axes of these channels 47 are inclined at the same angle in a direction opposite to the arrangement of the open end 48 (FIG. 3) of the explosion space 1. There are openings for the outlet of these channels

47 arranged in the cavity 43 with respect to the open end 48 of the explosion space behind the outlet 49 of the jet nozzle 44.

It has been experimentally proven that the distance ^ between the axis of the channel 11 and the axis of the spark plug

4 is expediently chosen within 15 to 60 inner diameter dj of the inner part 42 of the explosion space 1.

It is expedient to choose the distance 12 between the axis of the channel 11 in the wall of the tail end 41 of the explosion space 1 and the interface of its open end 48 also within 15 to 60 inside diameter d2 of this end 48.

The walls of the cavity 43 have between the parts 41 and 42 of the explosion space 1 a conical section 50 narrowing in the direction of the open end 48 of the explosion space 1, which section merges into a cylindrical section 53 via a cylindrical section 51 and a section 52 with counter cone , which is located near the open end 48 of the explosion space 1.

In order to select the optimal operating conditions of the jet nozzle 44, the distance h (FIG. 3) between its outlet 49 and the entry into the cylindrical section 52 of the tail end 41 of the explosion space 1 can be achieved by the joint displacement of the inner part 42 of the explosion space 1 and the nozzle 44 in Axial direction can be regulated.

The operation of the detonation coating system in the first variant (Fig. 1) is as follows.

In accordance with the specified cyclogram, the electronic control unit 54 (FIG. 1) sends pulses (the direction of which is indicated by arrows in FIG. 1) to electromagnetic control valves 31, 34, 35, 36, 55 and 56. The control unit 54 also sends in Signal to the high-voltage pulse generator 40, which supplies a signal for igniting the explosion mixture in the explosion space 1 of the spark plug 4.

During the entire operation of the system, the valve 56 is open and ensures the swirling of the gas which enters the annular cavity 19 via a main line 57

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(Fig. 2) and further flows through the ventilation partition 18 and through the tube 20 into the cavity of the bunker 10, loosens the coating material powder "B" and further escapes through a nozzle 58 in the cover 17 of the bunker 10.

At the start, the electromagnetic valves 34, 35 and 36 (for oxidant, neutral gas and fuel) open on command from the control unit 54, whereby the neutral gas valve 35 can be in two positions “open” or “closed”, whichever is the case an explosion mixture in the percentage ratio between the components is necessary.

By adding different amounts of neutral gas to the explosion mixture, the temperature, pressure and speed of the detonation wave can be regulated within wide limits with the aid of the valve 35, and the required operating state of the system for different coating materials can thus be quickly selected.

When the valves 34, 35 and 36 are opened, the oxidizing agent, neutral gas and fuel flow into the chamber 2, where they mix by forming a homogeneous explosion mixture which fills the explosion space 1 as it flows through the check valve 6 and the protective tube 5.

The amount of the coating material powder «B»

is determined by the doser 3, which operates as follows.

At a command from the control unit 54, the valves 31 and 55 are opened at the same time. When the valve 31 is triggered, its spindle 32 is drawn in by opening the flow cross section of the elastic tube 29.

Under the influence of the gas flow that flows through the valve 55 into the channel 14 of the nozzle 13, a negative pressure is generated in the mixing chamber 9 of the doser 3, as a result of which the suction of the powder “B” from the pipe 29, into which it flows from the Bunker 10 enters through the openings in its bottom 16 and the opening 27 in the membrane 26, takes place in this chamber 9. Under the action of the nozzle 13, the carrier gas flows together with the powder “B” from the mixing chamber 9 into the cylindrical section 59 of the nozzle 12, where they mix and, after passing through an enlarged cone 60, enter the explosion space 1.

After filling the explosion space 1 with the explosion mixture and coating material powder, all the valves are closed, and the control unit 54 sends a signal to open the neutral gas valve 35 (to blow through the chamber 2) and then to the pulse generator 40, which in turn sends out a signal to blow up the explosion mixture supplies the spark plug 4 in the explosion space 1.

As a result of the detonation of the explosive mixture, a high pressure and a high temperature occur in the explosion space 1, and there is a stormy development of explosion gases which are in a highly compressed state at the moment of the detonation and which are physical agents during their implementation instantaneous transition from the positional energy of the explosion mixture to the kinetic energy of the mobile gases takes place. This energy is transferred to the powder particles of the coating material suspended in the gas stream, as a result of which they heat up, are accelerated and form a coating on the surface of the workpiece when they emerge from the open end of the explosion space 1 (not shown).

After completion of the process described above, the explosion chamber 1 is blown with the same valve 35 with neutral gas. Then the cycle repeats.

The work of the detonation coating system in the second variant (FIG. 3) differs from that of the system in the first variant (FIG. 1) by the following.

After the neutral gas has displaced the residues of the explosion mixture from the processing chamber 2, the explosion mixture is ignited in the cavity of the inner part 42 of the explosion space 1.

As a result of the detonation of the explosion mixture, a very rapid combustion product stream is formed, which plunges at high speed through the jet nozzle 44 into the cavity 43, where this stream creates a vacuum at the outlet 49 of the nozzle 44, as a result of which the coating material powder is drawn out of the Dosator 3 in the cavity 46 of the shell 45 and further through the channels 47 into the cavity 43.

The energy of the combustion product stream is used to suction and convey the coating material powder into the explosion space 1. Furthermore, since the flow at the entry of the cylindrical section 51 from the tail end 41 of the explosion space 1 is strongly swirled, practically complete mixing of the powder with the explosion mixture is ensured.

Due to the specific nature of the process of supersonic outflow, the flow of the explosive mixture explosive products with the powder particles of the coating material suspended therein gains an even higher speed after passing section 52 with counter cone of the tail end 41 of the explosion space 1, which in addition to the high temperature is the most important factor in the Formation of coatings which are homogeneous in their composition with minimal porosity, firm adhesion to the workpiece and high operating properties.

The systems according to the invention in the two variants have high reliability, accuracy and operational reliability of all of their assemblies and units, which offers the possibility of increasing the effectiveness of the coating material.

The systems in the two versions can be used to apply multilayer coatings made from powders of different materials with great success. For this purpose, a plurality of inlet pipe sockets (not shown in FIG. 1) can be provided on the housing, to which the dosers similarly designed to those described above and filled with powders of different materials can be connected. By turning these dosers on in sequence, you can make multi-layer coatings. The thickness of these coatings can be regulated from the control panel without stopping the system according to the specified program.

When applying the coatings from different materials, the technological parameters of the process and thus also the operating modes of the system must be changed to adapt to the properties of each of these materials. Another advantage of the systems described above compared to the previous systems is the simplicity and manageability of changing these operating states, which amounts to turning the respective switch handles on the control panel, which means that the operator does not need to be highly qualified to implement the detonation coating according to the cycle's target program.

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2 sheets of drawings

Claims (10)

625 977 1. detonation coating system, with an explosion chamber (1), which is designed in the form of a tube closed at one end with at least one spark plug (4) arranged therein, with a chamber (2) for processing the explosion mixture, with a doser (3) for the coating material in the form of powder, which is connected to a mixing chamber (9), the doser (3) having a bunker (10) which is connected to the mixing chamber (9) by a channel (11) a device for regulating the cross-sectional area of the channel (11), and with a nozzle (13) for the inevitable delivery of the coating material into the explosion space (1), characterized in that the said device has a partition (18) made of gas-permeable material that the Partition (18) defines an annular cavity (19) for connection to a pressurized gas source in that it is arranged in the bunker (10) equidistant from its walls (15), and that in the channel (11) at its ver Connection point with the bunker (10) a check valve (26) is arranged, which shuts off the channel (11) in the event of a kick out of the explosion space (1). 2. Plant according to claim 1, characterized in that a joint at the connection point of the channel (11) with the bunker (10) is carried out, that a resilient membrane (26) is arranged in this joint, that this membrane one with the channel (11) has coaxial through hole (27) that connects the channel (11) with the cavity under the bottom (16) of the bunker (10), that the bottom (16) has holes for the passage of the coating material (B) that the Membrane (26) is provided with a conical projection (28) which serves as the seat of a valve which closes the opening (27) in the membrane (26) during its deflection upon kickback. 2nd PATENT CLAIMS 3. Plant according to claim 1, characterized in that in the middle of the bunker (10) a tube (20) made of gas-permeable material is arranged, the upper end of which is left through an opening in the cover (17) of the bunker (10) and for connection is provided with the pressurized gas source, while the lower end of the tube is supported on a conical projection (21) formed on the bottom (16) of the bunker (10) and has uniformly distributed through openings (22) for gas flow into the bunker (10), the Axes are directed at the same angle to its bottom (16). 4. Plant according to claim 1, characterized in that the device for regulating the cross-sectional area of the channel (11) through a coaxially arranged therein a tube (20) made of elastic material and on both sides thereof nozzle (30) and electromagnetic valve (31 ) is formed, which are arranged coaxially with each other and cooperate with the tube (29) to change its cross section. 5. Plant according to claim 1, characterized in that the mixing chamber (9) of the doser (3) with the explosion space (1) via a feed pipe (12) is connected, the corresponding end of which is arranged in an axial through-hole, which at the End face of the closed end of the explosion chamber (1) is attached. 6. System according to claim 1, characterized in that the length of the explosion chamber (1) is composed of two telescopically interconnected parts (41 and 42), of which the tail end (41) is the outer part and the second part ( 42) partially surrounds, in which a spark plug (4) is attached and which ends with a jet nozzle (44), an inner cavity (43) being formed between them, and the junction of these parts (41 and 42) of the explosion space (1) is enclosed from the outside with an annular casing (45) which, with the tail end (41), forms a cavity (46), which with the internal cavity mentioned (43) and the mixing chamber (9) of the doser (3) is connected. 7. Plant according to claim 6, characterized in that the cavity (46) of the ring jacket (45) with the cavity (43) of the tail end (41) of the explosion space (1) by means of channels (47) in communication, which from the open end (48) of the explosion space (1) are arranged behind the outlet (49) of the jet nozzle (44). 8. Plant according to claim 7, characterized in that the distance (lj) between the axis of the channel (11) and the axis of the spark plug (4) within 15 to 60 inner diameter (dj of the inner part (42) from the explosion space (1) selected is. 9. Plant according to claim 7, characterized in that the distance (It) between the axis of the channel (11) and the interface of the open end (48) of the explosion space (1) is selected within 15 to 60 whose inner diameter (d2). 10. System according to claim 6, characterized in that the walls of the cavity (43) of the tail end (41) of the explosion space (1) have a conical section (50) narrowing in the direction of the open end (48) of the explosion space (1) , which passes over a cylindrical section (51) and a section (52) with the counter cone into a cylindrical section (53) which is located not far from the open end (48) of the explosion space (1).