FR2586207A1 - DEVICE FOR THE APPLICATION OF DETONATION COATINGS - Google Patents

Abstract

The invention relates to techniques for applying coatings. THE DEVICE WHICH IS THE OBJECT OF THE INVENTION IS OF THE TYPE INCLUDING A CANNON 1, A POWDER DOSER 2 COMMUNICATING WITH CANON 1, A MIXING CHAMBER 3 COMMUNICATING WITH CANON 1 VIA A PROTECTIVE TUBE 4, AN INJECTION CHAMBER 8 COMMUNICATING WITH MIXING CHAMBER 3, A GASEOUS FUEL DUCT 11 CONNECTED TO INJECTION CHAMBER 8, A GAS COMBUSTIBLE DUCT 10 CONNECTED TO MIXING CHAMBER 3 VIA AN INJECTOR 9, AS WELL AS A MEANS OF PREVENTION, RETURN SHOCKS IN MIXING CHAMBER 3, A CONTROL BLOCK 7 AND AN EXPLOSION INITIATION ASSEMBLY 5 CONNECTED TO THIS, AND IS CHARACTERIZED IN THAT THE MEANS OF PREVENTING RETURN SHOCK IS ACHIEVED IN THE FORM OF A CLOSED TANK 12 CONNECTED TO THE FUEL LINE 11 IN THE NEARBY OF THE AREA WHERE IT COMMUNICATES WITH THE INJECTION CHAMBER 8. THE INVENTION MAY BE USED IN MECHANICAL CONSTRUCTIONS, IN ENERGY INDUSTRIES, THE AUTOMOTIVE, MEASURING DEVICES AND INSTRUMENTS RE AND IN OTHER BRANCHES OF THE INDUSTRY.

Description

The invention relates to devices for the application

  cation of coatings and, in particular,

  It can be used in mechanical constructions, energy industries, automotive, measuring instruments and instruments and in other branches of industry.

  There is a device for the application of

  by detonation using powdered materials, which includes a gun to detonate gas mixtures, a

  metering device communicating with the barrel, a system of

  gas supply, this system using, to mix the

  gaseous components and send them into the barrel, a mixture of

  injection type (USSR author's certificate No. 508994, part B05B 5/00, published in the bulletin published

  USSR "Discoveries, Inventions", no. 25, 1985).

  The device ensures a perfect blend of

  However, this device has the disadvantage that there is a risk of shock back when there is an overheating of the gas mixing zone of the device (appearance of stable combustion in the mixing zone).

  by injection). Shocks in return disrupt the function

  cyclic operation of the installation and may cause

  malfunction of the mixer in case of prolonged combustion of the gas.

  Besides this, there is an application device

  detonation coatings (collection "Coatingspro-

  of Metals "No. 16, published in 1982, Kiev: Kharla

  mov Ju. A. et al. "Optimization of the constructions of a gas detonation installation for the application of coatings", pp. 62 to 64), which comprises a barrel, a powder dispenser communicating with the barrel, a mixing chamber communicating with the barrel by means of a protective tube,

  an injection chamber communicating with the chamber of

  a gaseous fuel line connected to the injection chamber, a gaseous oxidizer line connected to the mixing chamber via an injector, and a means for preventing backlash in the mixing chamber; command and a boot set

  of the explosion connected to it.

  The means for preventing back-shocks in the mixing chamber is embodied, in this known device, in the form of a valve regulator and its function consists in closing the gas fuel line with a valve ( acetylene) and simultaneously open an auxiliary line of inert gas blowing (nitrogen) that fills the mixing chamber and the protective tube

before initiation of the explosion.

  It is obvious that the need to synchronize the beginning and the end of the blow by the neutral gas and the moment of the initiation of the explosion makes the installation more complex. Another difficulty lies in the fact that in case of excess of neutral gas, the latter can fill the mixing chamber, the protective tube and the priming zone

  of the explosion (the place where the candle

  ge) before the moment of the priming spark

  by the candle, so that the explosion does not take place.

  On the other hand, the neutral gas must completely expel the explosive gas mixture from the mixing chamber and create a "plug" in the protective tube. The presence of elements

  executives with cyclic movement (valves) decreases the fi-

  as a result of wear and tear of the equipment and the

  tion of the neutral gas with each shot

considerable summation of this gas.

  The object of the invention is to create a device for the application of detonation coatings, in which the

  means of preventing shocks in return would be to

  simple and reliable truction excluding the occurrence of combustion in the gas mixing zone, and not requiring

  a significant consumption of neutral gas.

  The aim is achieved by the fact that the application

  cation detonation coatings, comprising a barrel, a powder dispenser communicating with the barrel, a mixing chamber communicating with the barrel via a protective tube,

  an injection chamber communicating with the chamber of

  a gaseous fuel line connected to an injection chamber, a gaseous oxidant line connected to the mixing chamber via an injector, and a means

  prevention of shocks back into the mixing chamber

  ge, a command block and a boot set from the ex-

  plosion connected to the latter, is characterized, according to

  in that the back-shock prevention means is embodied in the form of a closed reservoir connected to the gaseous fuel pipe in the vicinity of its point

  communication with the injection chamber.

  This closed tank can be filled with pressurized neutral gas and placed in communication with the fuel line via a valve electrically connected to the control block.

  The coating application device

  nation, executed in accordance with the present invention, is simple and reliable construction, excludes the occurrence of a shock back in the gas mixing zone. In the variant of the device whose closed reservoir is connected to the fuel pipe, the device does not require, for its operation, a consumption of neutral gas, and in the closed-tank variant filled with pressurized neutral gas, neutral gas consumption is limited

  by the volume of the mixing chamber.

  The invention will be better understood and other purposes, details and advantages thereof will become more apparent to the

  light of the explanatory description which will follow from

  various embodiments given solely by way of nonlimiting examples, with references to the appended nonlimiting drawings in which:

  FIG. 1 represents a sectional view of a device

  for the application of detonation coatings according to the invention; - Figure 2 is a partial longitudinal sectional view of the same device as that of Figure 1, but the closed reservoir is filled with neutral gas. The device for the application of detonation coatings shown in Figure 1, comprises a barrel 1 provided with a water cooling jacket (not shown) and to which is connected a powder feeder 2, a chamber 3 for mixing gases , communicating, on the one hand, with the barrel 1 via a protective tube 4 in which is incorporated an explosion initiation assembly 5 provided with an ignition plug 6 electrically connected to a

  control block 7, and on the other hand, with an ignition chamber

  jection 8 which contains an injector 9. To the latter is connected a gaseous oxidizer line 10, while a gaseous fuel line is connected to the injection chamber 8. The device also comprises a means

  prevention of shocks back into the chamber of

  3, in the form of a closed reservoir 12 connected to the gaseous fuel pipe 11 near its point of communication with the injection chamber 8. In the variant of the coating application device shown in FIG. 2, unlike the device shown in FIG. 1, the reservoir 12 is connected to the gaseous fuel pipe 11 via a valve 13 electrically connected to the control block 7,

  said reservoir 12 being filled with a neutral gas (e.g.

  nitrogen) under a pressure greater than that prevailing

  in the gaseous fuel line 11.

  The coating application device by de-

  The toner shown in FIG. 1 operates in the following manner. The oxidant (which is usually oxygen or an air-oxygen mixture) is passed through the gaseous oxidant line 10 into the gas mixing chamber.

via the injector 9.

  It creates then a vacuum under the action of which the

  The chamber sucks the fuel (eg a hydrocarbon

  CnHm) from the gaseous fuel line 11. The gas in the closed reservoir 12 is also in the rarefied state (pressure below atmospheric pressure). From the gas mixing chamber 3, the formed mixture arrives in the protective tube 4, and then, via the explosion initiation assembly 5, in

the barrel 1.

  After filling the barrel 1, the detonation is triggered by means of the spark plug 6 under the action of an electric pulse coming from the control block 7. From the point of initiation, two detonation waves propagate: one in the barrel 1 and then towards its open end, the other in the protective tube 4 towards the gas mixing chamber 3. The detonation products that form behind the wave of detonation first arrive in the chamber 3, then in the injection chamber 8, the fuel pipe 11 and

the tank 12.

  During the movement of the detonation products, in front of the latter propagates a shock wave which directs a small volume V of oxidant and unmixed fuel

  in the tank 12 and the fuel line 11.

  In the fuel line 11, the portion said volume of oxidant that has arrived ultimately mixes with the gaseous fuel forming a saturated mixture of fuel that ignites on contact with the hot detonation products and burns slowly ( in comparison with the detonation) in the fuel line 11.The part of the volume V that has arrived in the tank 13 mixes with cold detonation products therein and due to the previous shot, thus losing its power

  of combustion. Then, the detonation products con-

  continue their movement by pushing the hot gas cap

  further in the fuel line Il and fill

  When the tank 12 is cooled down as it expands, the tank 12 is depressed. After a decrease in the pressure in the barrel 1, a slower process of relaxation of the pressures in the fuel line 11 and the tank 12 begins. hot gas cap comes out by the

  fuel line 11 and arrives in the ignition chamber.

  jection 8 o, from the tank 12, arrive the

  cooled detonation fuels that dilute the gas

that the combustion stops.

  The ratio between the volume of the tank 12 and the

  diameter of the orifice through which the reservoir 12

  with the fuel line 11 is chosen so that the time of relaxation of the pressure in the tank

  12 is not less than the relaxation time of the pres-

  in the fuel line 11 and is not

  less than the time interval between shots.

  The variant of the device represented on the

  gure 1 does not have valves which, because of their inertia, have an upper limit as to their frequency

  interlocking, which is of the order of 10 to 15 Hz.

  Relaxation of thepressions from the reservoir 12

  is not related to the movement of any part of the

  positive except gas. That's why the time to relax

  may vary within wide limits.

  The device made according to the variant

  2 operates in the same manner as the device shown in FIG. 1, the only difference residing in the fact that after the pressure drop in the barrel 1, the plug of the hot gas exiting through the pipe

  gaseous fuel 11 and entering the ignition chamber.

  jection 8 is diluted intensively and is cooled not by the cooled detonation

  tank neutral gas 12. The volume of neutral gas injected

  is adjusted by the opening time of the valve 13. A portion of the injected gas acts as a throttle

  fuel, coolant and inhibitor

  bustion. The advantage of the present device over known devices lies in the fact that it makes unnecessary a rigorous synchronization of the sending moments of the priming pulse on the candle 6 and opening

  13. In addition, there is a considerable saving in

  neutral gas. The neutral gas pressure can be

  within the limits of 49 to 78.5 kPa.

  A small portion of neutral gas can exclude

  the dilution of the fuel mixture, which raises the

the device.

  The closed reservoir 12 can be used in combination

  pairing with the valve 13 when operating with

  mixtures with low values of starting energy, for example

  ple, when using an acetylene-oxygen mixture

equimolar.

R E V IN DI C A T IO N S

  1. Apparatus for applying coatings by deter-

  nation, of the type comprising a barrel (1), a powder feeder (2) communicating with the barrel (1), a mixing chamber (3) communicating with the barrel (1) via a protective tube (4), a chamber injection nozzle (8) communicating with the mixing chamber (3), a gaseous fuel line (11) connected to the injection chamber (8), a gaseous oxidant line (10) connected to the mixing chamber ( 3) via an injector (9), as well as a means for preventing backlash in the mixing chamber (3), a control block (7) and a set (5) for priming the explosion (5) connected thereto, characterized in that the back-shock prevention means is in the form of a closed reservoir (12) connected to the fuel line (11) in the vicinity of the location where she communicates with the

injection chamber (8).

  2. Device according to claim 1, characterized

  in that the reservoir (12) is filled with a pressurized neutral gas and communicates with the fuel line (11) via a valve (13) electrically connected to the

control (7).