EP0239645B1 - Detonation coating device - Google Patents

Abstract

A detonation coating device comprises a sound-insulated deposition chambers (1) and a sound-insulated plenum ventilation chamber connected to the chamber (1), detonation equipment (24), a means (16) for transporting the article in relation to the end face (26) of a burrel (25) with a drive (34). The burrel (25) is located outside the chambers and its end is introduced the chamber (1) through a sealed inlet (19). The drive (34) is located outside the chamber (1) and is connected to the means (16) by a mechanical connecting element (33) through a sealed inlet (20). The intake opening (14) of the ventilation chamber is provided with a damper (40) and a means (41) for blowing compressed air through the chamber.

Description

The invention relates to a system for the detonation of coatings with a soundproof sputtering chamber for coatings, which has an inlet opening equipped with a cover, an inlet air opening and an exhaust air opening which is connected to the atmosphere via a ventilation system, with a soundproof ventilation chamber which has an inlet opening is connected to the sputtering chamber via the supply air opening and to the atmosphere via the inlet opening, with sputtering equipment for coatings, which has a tube with an open end cross-section, a metering device for the powdered material to be dusted, a gas supply system and a spark plug which connects to the tube connected and arranged outside the sputtering chamber and the ventilation chamber, with means accommodated in the sputtering chamber for displacing a product to be processed relative to the end cross section of the ro hres and with a drive mechanically connected to the means for moving.

In such a generally known system, the tube is arranged in the ventilation chamber and is connected to the metering device, the gas supply system and the spark plug via lines. The ventilation chamber is in the form of a jacket which comprises the tube with a gap, has openings in the side surface for the passage of the lines and is provided in the end surface with a series of inlet openings for the inflow of ventilation air. The exhaust air opening of the dusting chamber is provided with a soundproofing shield, which is attached in the dusting chamber in front of the exhaust air opening.

This system has small dimensions and accordingly requires little material for the sputtering chamber. However, the reduction in the volume of the sputtering chamber increases the risk of explosion, because in a smaller volume an explosive fuel gas concentration can develop significantly faster. The explosion can be triggered by sparking in the electric motor of the fan of the ventilation system when it is started up, if it is damaged, or by the electric drive of the means for moving the product. If ventilation is insufficient and the spark plug fails, an explosion can also occur while the system is operating.

In the known system, relatively easy access to the metering device, the gas supply system and the spark plug can be achieved because they are arranged outside the soundproofed chambers, but access to the actual pipe is associated with labor-intensive disassembly of the ventilation chamber. The design of the ventilation chamber in the form of a jacket encompassing the tube with a gap leads to a considerable increase in the length of the lines which connect the tube to the metering device, the gas supply system and the spark plug. This deteriorates the workability of the sputtering equipment and complicates its construction. Means are required to prevent the powder of the material to be dusted from settling and agglomerating in the line, to ensure optimum compactness of the powder dose supplied to the tube and to ensure effective cooling of the line connecting the gas supply system to the tube in order to automatically ignite the Avoid mixing in this line.

The external arrangement of the spark plug generally presupposes its attachment to the line that connects the gas supply system to the pipe. This is why there is a detonation in this line as well as in the pipe. Since the line is of considerable length, the powder particles which inevitably settle in it acquire sufficient energy and are sputtered onto the inner surface of the tube opposite the inlet opening of the connecting line. As a result, the pipe is quickly contaminated, and the coating of a coating serves as a source of automatic ignition of the mixture.

On the other hand, it is not possible in the known system to change the sputtering distance in a simple manner by moving the tube. This is prevented by the jacket, in which the openings cannot be formed as grooves, because the sound insulation is becoming increasingly poor. When it finally becomes necessary to construct the sputtering equipment, i.e. Changing the position and mutual orientation of the metering device, gas supply system and spark plug in relation to the pipe requires a corresponding change in the design of the ventilation chamber, i.e. a jacket with its own shape corresponds to each specific type of dusting equipment. This limits the possible uses of the system and increases the cost of its practical use.

In the known system, the sound insulation is also insufficient. The sound vibrations are emitted as a result of diffraction phenomena through the non-hermetically sealed openings in the jacket for the passage of the lines into the outside. In addition, the soundproofing of the exhaust air opening with the help of a sound absorbing screen only has a partial effect due to the diffraction of low-frequency sound waves.

Finally, in the well-known installation, a sufficiently effective removal of the particles of the non-dusted powder material from the dusting chamber is not ensured, as a result of which the operating conditions for driving the means for displacement are unfavorable and the risk of explosion is high. The sound absorption screen in front of the exhaust air opening proves to be a barrier on the way of the powder particles to be removed from the chamber. This leads to the accumulation thereof in the area of the dusting chamber, which can lead to an explosion, in particular in the case of metal powders in high concentration. The deposition of the powder on the mechanisms of the drive means of the displacement means greatly reduces its working capacity and requires the use of a structurally complicated protection.

The invention has for its object to design the system for detonation of coatings of the generic type so that with reduced dimensions, especially the dusting chamber and increased operator comfort, a safe commissioning of the system and a high level of soundproofing of the detonation equipment for dusting coatings in operation ensured will.

This object is achieved in the system of the generic type in that the tube of the sputtering equipment for coatings is arranged outside the sputtering chamber and the ventilation chamber, that the drive for the displacement means is installed outside the sputtering chamber, that the sputtering chamber is provided with two hermetically sealed bushings that through one passage the end of the tube with an open end cross section is introduced into the sputtering chamber, through the other passage an element of the mechanical connection of the drive with the means for displacement is inserted and that in the inlet opening of the ventilation chamber a slide and a means for inflating the dusting chamber and the ventilation chamber with compressed air.

It is expedient to install the drive means for the displacement in the ventilation chamber.

The system according to the invention has the advantage that reliable and effective sound insulation is ensured, since the pipe of the sputtering equipment for coatings and the elements of the mechanical connection of the drive with the means for displacement are introduced into the cavity of the sputtering chamber with hermetic sealing of the bushings, so that the sputtering chamber has no orifices which directly connect its volume to the surrounding space and would therefore pass noise.

In the system according to the invention, the degree of effectiveness of the sound insulation does not depend on the design of the dusting equipment for coatings, because only a part of the pipe with an open end cross section is hermetically sealed in the dusting chamber. Otherwise, the construction of both the sputtering chamber and the venting chamber is not dependent on the type and arrangement of the sputtering equipment for coatings.

The system according to the invention is also easy to operate because its main elements, i.e. the metering device, the gas supply system, the spark plug and the drive of the displacement means are arranged outside the sputtering chamber, which is why good access to them is ensured, the dose of the powdered material to be sputtered and the sputtering distance being regulated directly during the sputtering process without violating the occupational safety regulations with regard to the impact of noise on the operating personnel.

The system ensures reliable coating equipment for coating because the metering device, the gas supply system and the spark plug can be connected to the pipe without the use of long connecting lines, because most of the pipe is outside the soundproofed chambers.

The dimensions of the system, its total mass and the cost of materials for the sputtering chamber are small, which simplifies the manufacture and assembly of the system, especially since the drive for moving the product is installed outside the sputtering chamber.

Despite the relatively small dimensions of the sputtering chamber, a safe commissioning of the system is ensured even in the event of unnoticed damage to the gas supply system during the idle period, which leads to the escape of the fuel gas into the cavity of the sputtering chamber, thereby ensuring that a slide and a are in the inlet opening of the ventilation chamber Means for blowing out the chambers with compressed air are built in, so that all cavities of the system can be blown out before commissioning.

Because the small dimensions of the dusting chamber enable high air speeds, effective ventilation is achieved. The ventilation system does not require explosion protection, since the blowing out before commissioning excludes the possibility of an explosion of the ventilation system when starting and the formation of explosive fuel gas concentrations during the operation of the system is not possible.

Since the drive for the displacement means is installed outside the sputtering chamber, reliable protection of the drive against the action of heat and powder of the material to be sputtered is ensured without the use of constructive protective measures which would complicate the drive, while at the same time the possibility of an explosion is excluded when starting the drive.

• Fig.1 eine erste Ausführungsform der Antage im Längsschnitt,
• Fig. 2 die Anlage in der Draufsicht, teilweise im Schnitt,
• Fig. 3 den Schnitt 111-111 von Fig. 1,
• Fig. 4 den Schnitt IV-IV von Fig. 2,
• Fig. 5 eine Draufsicht auf eine zweite Ausführungsform der Anlage und
• Fig. 6 den Schnitt VI-VI von Fig. 5.

Exemplary embodiments of the invention are explained in more detail with reference to drawings. Show it:

• 1 shows a first embodiment of the antage in longitudinal section,
• 2 the plant in plan view, partly in section,
• 3 shows the section 111-111 of FIG. 1,
• 4 shows the section IV-IV of FIG. 2,
• Fig. 5 is a plan view of a second embodiment of the system and
• 6 shows the section VI-VI of Fig. 5th

The system for the detonation application of coatings has a dusting chamber 1 (FIGS. 1, 2) provided with a soundproofing, which has an entry opening 2 (FIG. 2) in one of the side walls, on the periphery of which a seal 3 is fastened to the outer surface. The opening 2 is equipped with a pivotable cover 4 provided with soundproofing, which cooperates with the seal 3 in the closed position and ensures hermetic sealing of the entry opening 2. An inlet air opening 5 (FIGS. 1, 3, 4) or a row of inlet air openings and an exhaust air opening 6 (FIGS. 1, 2, 3) are embodied in the walls of the sputtering chamber 1. The supply air opening 5 and the exhaust air opening 6 are arranged at the greatest possible distance from one another, in the present example on one and the same wall of the sputtering chamber 1. The exhaust air opening 6 communicates with the atmosphere or with the outside space via the ventilation system 7 (FIG. 4). The ventilation system 7 is hermetically sealed and contains an exhaust air receiver 8 (Fig. 2, 4), cleaning agent 9 (Fig. 4) for cleaning the ventilation air, e.g. Cyclones, an air suction line 10, which is connected to the exhaust opening of a fan 11 (Fig. 3, 4), and an air outlet line 12, which is led out of the operating room (not shown). A ventilation chamber 13 (FIGS. 2, 3, 4) having a soundproofing is hermetically connected to the dusting chamber 1, the upper wall of which has an inlet opening 14 (FIGS. 2, 4) for the ventilation air, which is connected to the atmosphere as a connection piece is trained. The connection to the atmosphere can be established via a system of supply air lines with a forced supply of air from a supply air fan (not shown). The ventilation chamber 13 is connected to the sputtering chamber 1 via the supply air opening 5.

Guides 15 (FIGS. 1, 3) are fastened in the sputtering chamber 1, on which a means 16 (FIGS. 1, 3) for moving a product to be processed is mounted. This means 16 is designed in the form of a wheel carriage which can be moved linearly on the guides 15. The wheel carriage is provided with a tensioning device 17 (FIG. 1), which is rotatable with respect to its axis, and with a receiving tip 18. The sputtering chamber 1 is provided with two hermetically sealed bushings 19 and 20 (FIG. 1) which are designed as sleeves which are built into the walls of the sputtering chamber 1 and are equipped with seals.

The bushing 19 is located in the upper wall, ie in the ceiling of the sputtering chamber 1. The axis of the hermetically sealed bushing 19 is perpendicular to the axis of rotation of the clamping device 17 and intersects with this axis. The hermetically sealed bushing 20 is coaxial with the tensioning device 17. On the wall of the sputtering chamber 1 containing the hermetically sealed bushing 19, a threaded column 21 (FIG. 1) with a support nut 22 (FIG. 1) is mounted. The support nut 22 is designed such that that it can cooperate with a sleeve 23 carrying a cantilever.

The system also includes sputtering equipment 24 for coatings with a water-cooled tube 25 (FIG. 1) with an open end cross-section 26, with a metering device 27 for the powdery material to be dusted, with a spark plug 28 and with a gas supply system 29 which is connected to the tube 25 stay in contact. The water-cooled pipe 25 is rigidly connected to the cantilever of the sleeve 23. The gas supply system 29 includes valves 30, 31, each in a fuel gas line and an oxygen line, and a mixer 32 for gases. The spark plug 28 is attached to a main line of the gas supply system 29, which connects the mixer 32 to the pipe 25. The mixer 32 and the main line with the spark plug 28 are water-cooled.

The tube 25 is inserted into the sputtering chamber 1 via the hermetically sealed feedthrough 19 such that it can move linearly along the axis of the feedthrough 19 such that the end of the tube 25 having the open end cross section 26 within the sputtering chamber 1 in each working position located. The remaining part of the tube 25 and together with it the metering device 27, the spark plug 28 and the gas supply system 29 are located outside the sputtering chamber 1 and the ventilation chamber 13.

An element 33 (FIGS. 1, 2) of a mechanical connection, which has the shape of a hollow stick 33, is introduced into the sputtering chamber 1 via the hermetically sealed passage 20. The stick 33 is linearly displaceable along the axis of the passage 20 and is mechanically connected to the means 16 for displacing the product relative to the end cross section 26 of the tube 25 inside the chamber 1.

The drive 34 of the means 16 for moving the product is installed outside the sputtering chamber 1 and is also connected to the stick 33. The drive 34 has an electric drive 35 for rotation and an electric drive 36 for linear displacement of the product. The drive 34 has an intermediate shaft 37 (FIG. 1) which extends through the interior of the hollow stick 33 and is rotatable about its own axis in bearings which are arranged inside the stick 33. The intermediate shaft 37 is in mechanical connection with the clamping device 17 of the means 16 for displacement and with the electric drive 35, which is rigidly connected to the stick 33. The electric drive 36 is with a screw 38 (Fig. 1) with a gear nut 39 equipped, the gear nut 39 cooperates with the stick 33 to transmit its movement to it. The cavity of the stick 33 and the intermediate shaft 37 are protected on the side of the sputtering chamber 1 by seals.

The inlet opening 14 of the ventilation chamber 13 is provided with a slide 40 (FIGS. 1, 2, 4) and a means 41 (FIGS. 2, 4) for blowing out the dusting chamber 1 and the ventilation chamber 13 with compressed air. The means 41 is designed as a compressed air line with an electromagnetic valve 42 (FIG. 1) which is inserted into the inlet opening 14. The slide 40 can hermetically seal the inlet opening 14. The open and the closed position of the slide 40 is fixed by respective sensors 43, 44 (FIG. 4) for the slide position, which are attached to the ventilation chamber 13. An explosion remote transmitter 45 (FIG. 1) is installed in the sputtering chamber 1, for which purpose a microphone or an electromagnetic remote receiver is used. A sensor 46 (FIG. 3) for determining ventilation is attached to the air outlet line 12 of the ventilation system 7, for which purpose a relay converter for pressure, delivery pressure and train into an electrical signal is used.

The system can be provided with a number of additional elements (not shown) which increase the security of their systems and the degree of automation as well as improve the quality of coatings. Thus, a means for a continuous or pulse-like free fire in the form of an electric heater or an additional arrester, such as an additional spark plug, can be fitted inside the dusting chamber 1 in front of its exhaust air opening 6. An additional sound level transmitter, such as a microphone, a telephone, a noise meter with an electrical output, can be provided outside of the soundproof dusting chamber 1 and ventilation chamber 13. If this transmitter is arranged in the vicinity of the metering device 27 of the dusting equipment 24, it simultaneously fulfills the function of a sensor for the fill level of the powdery material to be dusted in the metering device 27. Explosion flaps can be arranged in the upper wall of the dusting chamber 1. An additional compressed air source for blowing on the product to be processed can be introduced into the cavity of the chamber 1.

The system for detonation dusting is provided with an electrical control system 47 (FIG. 1) which processes information and issues commands and is a programmable command device or a microcomputer. The transmitters 43, 44, 45, 46 and the valves 30, 31, 42, as well as any auxiliary elements, are electrically coupled to the electrical control system 47.

In the second embodiment of the system shown in FIGS. 5 and 6, the drive 34 of the means 16 for moving the product is installed in the sputtering chamber 1 and in the ventilation chamber 13, while the elements of the ventilation system 7, that is to say the cleaning means 9, the air suction line 10 , the fan 11 and part of the air outlet line 12, are housed in an additional soundproof housing 48. The housing 48 is hermetically connected to the wall of the sputtering chamber 1 which has the exhaust air opening 6. The sputtering chamber 1 is designed as a metal welded construction, with its base body forming an undivided, massive scaffold 49 made of steel (FIG. 1, 2, 3, 6). It is also possible to design this scaffold with metallic double walls, the space between them with a pourable mass, e.g. filled with sand. On the inner surface of the frame 49, on the side of the open end cross-section 26 of the tube 25, mats made of sound-absorbing material 50 are laid in a cover made of fiberglass, which are protected by a perforated thin sheet 51 made of steel or dural.

The soundproofing of the pivotable cover 4 is constructed similarly. The structure of the sound insulation of the ventilation chamber 13 (Fig. 3, 4) and the additional housing 48 (Fig. 5, 6) is analogous, but the metal structure is significantly less solid and consists of sheet metal, for example.

The detonation dusting system works as follows:

At the start of work, the system is in the initial state in which the slide 40 is closed, i.e. it hermetically closes the inlet opening 14 of the ventilation chamber 13. The pivotable cover 4 provides a hermetic seal for the dusting chamber 1.

The control system 47 is turned on. Since the slide 40 is closed, the encoder 44 blocks the activation of the ventilation system 7, ie the fan 11. The absence of a signal from the encoder 46 for the presence of ventilation in turn blocks the possibility that the drive 34, ie the electric drives, from the control system 47 35, 36 of the means 16 for moving the product and the sputtering equipment 24, ie the valves 30, 31 of the gas supply system 29 and the spark plug 28, are activated. In response to a signal from the control system 47, the valve 42 of the means 41 for blowing out the cavities in the system is opened. The compressed air flows freely out of the means 41 for blowing out. Since the slide 40 and the lid 4 hermetically close and the pipe 25 are inserted into the sputtering chamber 1 via the hermetically sealed bushing 19 and the stick 33 via the hermetically sealed bushing 20, the air only has the possibility of the exhaust air opening 6 and that Vent system 7 to emerge. The air successively fills the ventilation chamber 13 from top to bottom and then passes through the supply air opening 5 into the dusting chamber 1, from which it flows through the exhaust air opening 6 into the ventilation system 7 and exits into the atmosphere outside the production space. After a predetermined period of time, a signal is sent to the tax tion system 47, the valve 42 of the means 41 for blowing out is closed, and the blowing out that takes place before the start stops. The blow-out which takes place before the start-up guarantees the safety of the further start-up regardless of the operational condition of the gas supply system 29 of the sputtering equipment 24 after long-term interruptions in operation of the system, but also after regular interruptions. If an explosive fuel gas concentration has formed in the sputtering chamber 1 and the ventilation chamber 13 during the operational rest period due to unnoticed malfunction-related fuel gas leaks, for example when the fuel gas valve 30 is not intact, this concentration decreases continuously when blowing out with air. With a sufficient duration of the blowing process, the fuel gas content in the cavities of the ventilation chamber 13 and the sputtering chamber 1 is reduced to a non-hazardous level. Neither the dusting equipment 24 nor the electric motors 35, 36 nor the exhaust fan 11 can be left on until the blowing out has ended. ie the possibility of an ignition and explosion in the sputtering chamber 1 and in the ventilation chamber 13 originating from all possible sources is eliminated. The blow-out time required to ensure the safety of the system is determined by the free volume in the sputtering chamber 1 and in the ventilation chamber 13 and in the ventilation system 7. If, for example, the diameter that determines the air consumption from the mean 41 is 10 mm, the volume of the cavities is 0.8 m ³ and the initial concentration of the fuel gas in the form of acetylene in the cavities of the sputtering chamber 1 is 70% after a leakage caused by a fault , the blow-out time is at least 3.5 min. After 3.5 min. After blowing out with air, the acetylene concentration reaches 1.5%. This shows that blowing out the soundproofed dusting and ventilation chambers 1, 13 by means of compressed air to ensure the safety of further commissioning, especially if they have relatively small volumes or dimensions, is expedient. Since the fan 11 and its electric motor do not work when blowing out, the fan and its drive can be conventional, ie not explosion-proof.

After blowing out, the slide 40 is opened, the ventilation chamber 13 being connected to the atmosphere by means of the inlet opening 14. From the position transmitter 43 of the slide 40 comes a signal that allows the fan 11 to start. At the command of the control system 47, the fan 11 is switched on and runs until the work is completed. The ventilation air flows in via the inlet opening 14, while the air is removed via the exhaust air opening 6 of the sputtering chamber 1 via the ventilation system 7. In the ventilation chamber 13 there is an overpressure with respect to the sputtering chamber 1. As soon as the delivery pressure in the air outlet line 12 of the ventilation system 7 reaches the permissible value, the transmitter 46 responds to the presence of the ventilation flow. This enables the drive 34 to be switched on and the sputtering equipment 24 to be activated on a signal from the control system 47. Furthermore, any failure or damage in the ventilation system 7, which causes the delivery pressure to drop below the level controlled by the transmitter 46, leads to an immediate shutdown of the sputtering equipment 24 and the drive 34.

After switching on the ventilation, the operator removes the cover 4 from the sputtering chamber 1 and introduces a product to be processed via the entry opening 2 of the sputtering chamber 1 onto the means 16 for moving the product. The product is fastened in the clamping device 17 and, if necessary, pressed by the receiving tip 18. Thereafter, by adjusting movements of the wheel carriage of the means 16 for sliding on the guides 15 by hand or using the drive 34, the starting position of the product to be processed is achieved in relation to the open end cross section 26 of the pipe 25 of the sputtering equipment 24. The operator brings the lid 4 into the closed position and closes the entry opening 2 of the sputtering chamber 1 with the aid of clamping means. The hermetic seal is achieved by the action of the cover 4 on the seal 3.

Thereafter, the operator adjusts the gas supply system 29, opens the cooling water supply into the pipe 25 and the mixer 32 for gases, and adjusts the required atomizing distance. The regulation of the sputtering distance takes place in such a way that the bearing bush 23 moves on the threaded column 21 and together with it also the pipe 25 by rotating the support nut 22. The tube 25 moves along the axis of the hermetically sealed passage 19 of the sputtering chamber 1. The tightness of the sputtering chamber 1 is not impaired here. With this arrangement, a change in the sputtering distance, i.e. the position of the open end cross-section 26 of the tube 25 in relation to the product to be processed, can be made directly during the coating of the product by dusting without obstacles.

Then, on a signal from the control system 47, the dusting equipment 24 and the drive 34 of the means 16 for moving the product are switched on. The valves 30, 31 of the gas supply system 29 are opened. The fuel gas and oxygen continuously enter the mixer 32 for gases. The working gas mixture reaches the pipe 25 from the mixer 32 and fills it. At the moment of the complete filling of the tube 25, so if the gas mixture reaches the open end cross-section 26, a discharge pulse arrives at a signal coming from the control system 47 into the spark gap of the spark plug 28. A detonation develops in the tube 25. The metering device 27 of the sputtering equipment 24 for coatings does not operate on the first detonation cycle, so that no coating is applied. The detonation products act on the powder of the material to be dusted in the metering device 27 and convey the prepared powder dose into the tube 25. In the second and subsequent detonation cycles, the powder of the material to be dusted into the tube 25 is accelerated to high speeds and fused with detonation products. When leaving the open end cross section 26, the powder particles interact with the surface of the product and form a coating thereon. Since in this type of system the design of the sputtering equipment 24 does not depend on the dimensions and the arrangement of the sputtering chamber 1 and the ventilation chamber 13 with the exception of the diameter of the hermetically sealed bushing 19 and the outside diameter of the pipe 25, high operational reliability and good work performance become of sputtering equipment 24 is reached. The length of the connecting lines which connect the metering device 27, the mixer 32 and the spark plug 28 to the pipe 25 is only determined in this system by the design of the spraying equipment 24 itself. There are therefore no problems due to a balling up of the powder, an instability of an automatic, uncontrolled mixture ignition or a blockage of the pipe 25 with respect to the point of introduction of the fuel mixture.

Since the metering device 27, the spark plug 28 and the gas supply system 29 are arranged outside the soundproofed dusting and ventilation chamber 1 and 13, respectively, their operation and replacement of assemblies are simple. Free access to the metering device 27 enables mechanical control of the powder dose, i.e. of the sputtering performance, also directly during the sputtering process, because the tightness of the sputtering chamber 1 remains guaranteed during the regulation of the dose and therefore the working conditions of the operator are not affected. The fact that the large part of the tube 25 is outside the sputtering chamber 1, it can be easily cleaned because it does not involve disassembly of the sputtering equipment 24.

Every detonation pulse is accompanied by powerful sound. This sound is detected by the transmitter 45, which generates an electrical signal. This signal is processed by the control system 47 in such a way that if the time interval between the arrival of the neighboring signals coming from the explosion generator 45 coincides with a predetermined ignition period, i.e. Frequency of the impulse from the control system 47 to the spark plug 28, the valves 30, 31 of the gas supply system 29 are kept open.

If the spark plug 28 fails or the flame front penetrates into the mixer 32 for the gases, that is to say in the event of a flashback, the next explosion does not occur. But there is also no sound impulse accompanying the explosion. If the sound is absent for a period of time that exceeds the predetermined working interval between the detonation pulses, the so-called launches, by 40 to 50%, the control system 47 switches off the valves 30 and 31 and the supply of gases stops. The drive 34 is also switched off. Thus, the supply of the non-reactive explosive mixture into the sputtering chamber 1 or a burning in the mixer 32 can exist under the condition that the valves 30, 31 are hermetically sealed for a very short time of at most 0.5 s.

This is essential both from the point of view of the possible failure of the mixer 32 and in connection with the fact that the volume of the sputtering chamber 1 is relatively small in this system. If the ventilation is working, no explosive fuel gas concentration can form within such a short period of time.

The noise accompanying the detonation pulses in tube 25 is primarily aerodynamic. This means that the water-cooled pipe 25 as well as other elements of the equipment 24 must have sufficient rigidity, mass and structure, the sound source being the open end section 26 of the pipe 25.

The sound insulation is achieved in the system in the following way: The sound waves first propagate from the open end section 26 of the pipe 25 in the soundproof sputtering chamber 1. This results in a reduction in noise due to the dissipation of the sound energy in the pores of the sound absorbing material 50 and by multiple reflection and scattering of the sound energy when the sound waves interact with the massive, i.e. an undivided framework 49 having a sufficient specific surface mass. The effectiveness of the absorption of the sound penetrating through the perforation of the sheet 51 into the sound absorbing material 50 is higher for the high and medium frequency component of the spectrum of sound vibrations that arise, i.e. for frequencies of 1000 Hz and higher. The solidity of the framework 49 is of crucial importance for sound vibrations in the range from 250 to 1000 Hz. For the sound waves in the range from 32 to 250 Hz, in addition to the mass, the rigidity of the structure of the scaffold 49 is essential.

Here, the tightness of the sputtering chamber 1 is of considerable importance for sound vibrations of all frequencies from the standpoint of sound insulation. The direct exit of the sound waves from the sputtering chamber 1 into the production room can do everything Undo measures to ensure sound insulation. It is therefore important that the soundproof cover 4 hermetically seals the opening 2 in this system and that the bushings 19, 20 are hermetically sealed.

Furthermore, the mutual butt connections of the elements of the sputtering equipment 24, that is to say the connections of the mixer 32 for gases, the spark plug 28 and the metering device 27 to the tube 25, and also the internal connections in these systems, are made hermetically sealed. This is important not only from the point of view of noise reduction, but also for safety reasons.

In the system described, the sound vibrations can only freely emerge from the sputtering chamber 1 through the supply air opening 5 and the exhaust air opening 6.

If the already weakened sound waves pass through the supply air opening 5, the front of the sound waves expands when they enter the ventilation chamber 13, with some of their energy being lost. Then the sound interacts with the surface of the sound absorbing material 50 of the ventilation chamber 13 via the perforation of the sheet 51 and is finally dampened.

The axes of the supply air opening 5 of the sputtering chamber 1 and the inlet opening 14 of the ventilation chamber 13 form a right angle, as a result of which a radial sound passage is excluded. The degree of effectiveness of the sound insulation of the sound that penetrates through the supply air opening 5 is determined by the volume and the surface of the soundproof ventilation chamber 13.

In this system, these parameters are in no way related to the arrangement and construction of the sputtering equipment 24. Since the surface of the sound absorbent 50 in the ventilation chamber 13 is considerable in this system, the noise level at the outlet, i.e. at the inlet opening 14, even lower than the noise level at the operator's workplace in front of the lid 4. It is 78 dBa.

The sound vibrations that penetrate the exhaust air opening 6 propagate in the ventilation system 7, i.e. in the exhaust air sensor 8, the cleaning agents 9, in the air suction line 10, in the fan 11 and in the air outlet line 12. However, all of these elements are themselves in soundproof cavities housed, which is why the sound entering the ventilation system 7 does not exceed the limits of the system. In the embodiment of the system shown in FIGS. 1 to 4, this is the cavity of the ventilation chamber 13, and in the embodiment of the system shown in FIGS. 5, 6, this is the additional soundproof housing 48. In addition, the elements of the ventilation system 7 are like that Detergent 9, e.g. Cyclones, and the fan 11 powerful barriers on the way of aerodynamic noise. Due to their considerable flow resistance, they act like reflection silencers. The fan 11 in the form of a medium pressure or high pressure fan, i.e. a high-speed fan is a source of additional noise. This noise cannot be compared to the sound of the detonation impulses. To suppress it, it is sufficient to accommodate the fan 11 in the soundproof volume of the ventilation chamber 13 or the housing 48, as shown.

The system is able to reduce the noise level to approximately 80 dBa with an output noise level of approximately 140 dBA.

When dusting, the powder of the material to be dusted, which is ejected from the tube 25, is not completely used for dusting. A considerable amount of the powder particles, namely the particles which have no energy which is sufficient to reach the product surface and to produce a coating, are scattered in the sputtering chamber 1. Most of this excess powder is collected by the ventilation system 7. The particles are discharged through the flow of ventilation air through the exhaust air opening 6 of the dusting chamber 1 and reach the cleaning agents 9 in the form of cyclones and / or bag filters via the exhaust air receiver 8, where they are braked and settle. Cleaned air flows through the air suction line 10 and is discharged by the fan 11 via the air outlet line 12.

A complete removal of the powder particles from the chamber 1 is not possible. By installing the drive 34 outside the soundproof sputtering chamber 1, however, contamination of its mechanisms or their seizure is avoided. Since wear is not noticeable, the accuracy of displacement is retained. The usual lubricants can be used because the mechanisms of the actuator 34 are outside the zone of thermal effects that accompany the detonation sputtering. The dimensions of the sputtering chamber 1 are additionally reduced because the drive 34 is located outside of it. This reduces the overall mass of the system, reduces the cost of materials and simplifies assembly.

The accommodation of the drive 34 in the ventilation chamber 13 (FIGS. 5, 6) allows its volume to be used advantageously. In this case, the drive 34 is continuously blown with the supplied ventilation air, which flows from the inlet opening 14 of the chamber 13 to the supply air opening 5 of the chamber 1. The powder particles do not reach the mechanisms of the drive 34 because an overpressure arises in the ventilation chamber 13 in relation to the sputtering chamber 1. The electric motors of the drive 34 are designed to be spark-proof.

The displacement of the product during dusting is carried out as follows: The electric drive 35, which serves for rotation, rotates the intermediate shaft 37, which in turn rotates transfers movement to the clamping device 17 of the means 16 for moving. The electric drive 36 for the linear displacement rotates the screw 38, the gear nut 39 moving on it. The gear nut 39 transmits its movement to the stick 33, which moves along the axis of the hermetically sealed passage 30 of the sputtering chamber 1. The intermediate shaft 37 located in the hollow stick 33 moves together with it and the electric drive 35 which is attached to the stick 33. In this case, the intermediate shaft 37 simultaneously displaces the wheel carriage forming the means 16 connected to it on the guides 15. The linear displacement can take place step by step or continuously. The shift program can be specified by the control system 47.

The installation of the drive 34 outside the sputtering chamber 1 allows a simple structure because the elements of the drive 34 do not have to be protected against finely dispersed wear particles. The operation of the drive 34, its repair and assembly are also greatly simplified.

After dusting on the product has ended, the valves 30, 31 of the gas supply system 29 are closed in response to a control signal. The supply of high voltage pulses to the spark plug 28 is interrupted. The drive is switched off. The lid 4 is removed from the sputtering chamber 1. The finished product is removed from the means 16 for displacement via the opening 2.

After the sputtering work has ended, that is to say at the end of the working shift, the fan 11 is switched off. The slider 40 is brought into the initial state, i.e. the inlet opening 14 is hermetically sealed with the slide 40. The lid 4 is brought into its hermetic sealing position on the sputtering chamber 1. Thereafter, the gas supply system 29, i.e. the valves of the gas sources and the like, and finally the control system 47 is turned off.

Claims (2)

1. A plant for the detonation application of coatings

having a sound-proofed spraying chamber (1) for coatings, comprising a feed opening (2) provided with a cover (4), an air-supply opening (5) and an air-discharge opening (6) communicating with the atmosphere by way of a venting system (7),

having a sound-proofed aerating chamber (13), comprising an entry opening (14), [and] connected to the spraying chamber (1) by way of the air-supply opening (5) and to the atmosphere by way of the entry opening (14),

having a spraying appliance (24) for coatings, comprising a tube (25) with an open end cross-section (26), a metering means (27) for the powdered material to be sprayed, a gas- supply system (29) and an ignition plug (28), which are connected to the tube (25) and are arranged outside the spraying chamber (1) and the aerating chamber (13),

having a means (16) disposed in the spraying chamber (1) for the displacement of an article to be treated relative to the end cross-section (26) of the tube (25), and

having a drive (34) mechanically connected to the means (16) for displacement, characterized in that

the tube (25) of the spraying appliance (24) for coatings is arranged outside the spraying chamber (1) and the aerating chamber (13),

the drive (34) of the means (16) for displacement is fitted outside the spraying chamber (1),

the spraying chamber (1) is provided with two hermetically sealed bushings (19, 20),

the end of the tube (25) with the open end cross-section (26) is introduced through one bushing (19) into the spraying chamber (1),

an element (33) for mechanically connecting the drive (34) to the means (16) for displacement is introduced through the other bushing (20), and

a slide (40) and a means (41) for purging the spraying chamber (1) and the aerating chamber (13) with compressed air are fitted in the entry opening (14) of the aerating chamber (13).

2. A plant for the denotation application of coatings according to Claim 1, characterized in that the drive (34) for the means (16) for displacement is fitted in the aerating chamber (13).

Images