JPS6056543B2 - Detonation coating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the practice of coatings using hot spray techniques, and more particularly to apparatus for detonation coatings.

The present invention is used in the metallurgical and chemical industries and in dynamic engineering, and is particularly useful for applying coatings on parts that are subject to intense corrosion and erosion during use. It is common knowledge that the amount of coating applied using a detonation wave depends on the temperature and velocity of the coating material particles just before impacting the surface of the workpiece to be coated.

Therefore, attempts to improve detonation coating equipment with the aim of improving coating quality have been
It is mainly concentrated on the unit devices of the detonation coating device, on whose operation the above parameters depend, such as the mixed gas supply device and the powder feed device for feeding the powder into the detonation chamber. One of the most important factors determining the stability of the above parameters of the coating applied on the workpiece is also the stability of the amount of powder fed into the detonation chamber in each cycle.

However, this is associated with a number of considerable difficulties, including both imperfections in the equipment for metering and delivering the powder into the detonation chamber and the instability of certain physical properties of the powdered coatings used. There is. U.S. Pat. No. 3,884,415 includes a detonation chamber in the form of a barrel with one end sealed, a spark plug located within the barrel, a mixed gas supply device, and a powder supply device. A detonation coating device is described in which both devices communicate with a detonation chamber.

The powder feeder includes a batch meter having a feed hopper and a tubular body communicating with a detonation chamber. A vibe line is connected to the tubular body that communicates the batch meter with a gas carrier source. A valve is provided at the outlet of the vibe line. The tubular body houses a slide valve that acts as a shutoff device. The device also includes a control device electrically connected to the mixed gas supply device, the spark plug and the batch meter valve, respectively.

When the batch meter valve opens in response to a signal from the control device's setting device, the powder detonates. - Sent to the room.

In this case, the carrier gas is pumped into the cavity of the tubular body and moves the sliding valve, so that the cavity provided in the cavity and before this moment aligns with the discharge hole of the hopper and is consequently filled with powder. The passageway that was previously located is now aligned with the supply tube that communicates the tubular body with the detonation chamber and the bypass tube that is connected to the carrier gas-filled cavity of the tubular body. As a result, powder is injected into the detonation chamber from the passageway in the slide valve. However, even though the slide valve passage, which determines the amount of powder injected into the detonation chamber, has a constant volume, as the powder level in the hopper of the batch meter decreases, the powder flow rate decreases through the slide valve passage. Since less powder is sent inside,
The amount of powder may vary.

Furthermore, the amount of powder loaded may be reduced as a result of a reduction in the flow area of the feed tube, which may occur due to clogging of the feed tube. A reduction in the amount of powder delivered to the detonation chamber results in overheating and combustion of this powder during detonation. In addition to this, the insufficient amount of powder causes both the chemical and phase composition of the resulting coating to be different from the initial coating, and especially such coatings to have too high an oxide content. become. Conversely, if the amount of powder exceeds the required amount, the powder will not be heated to the required temperature and the resulting coating will be porous and unstable. The above drawbacks are described in Japanese Patent Application Laid-Open No. 55-1291. a detonation chamber formed in the form of a barrel with one end sealed, a spark plug installed in the barrel, a mixed gas supply device including a mixer communicating with the detonation chamber, and for delivering coating powder to the detonation chamber. detonation coating equipment having a powder feeder and a powder feeder. A batch meter incorporated within the powder feeder includes a feeder that communicates with the detonation chamber. Powder is conveyed to the batch meter by means of a carrier gas supplied from a carrier gas source which is in communication with the batch meter by a valve. The coating device further includes a control device electrically connected to the spark plug, mixer valve and batch meter valve, respectively, and an open end of the barrel for controlling the amount of powder contained in the detonation product. a powder detector mounted on the detonation product and capable of responding to changes in the amount of powder contained in the detonation product; a voltage amplifier, a first power amplifier, an integrating circuit RCl and a voltage amplifier connected in series; a converter comprising a second power amplifier. The device for controlling the amount of powder has an outlet connected through a ThreshOldelement to a carrier-gas pressure regulator in the powder feeder, which controls the amount of powder contained in the detonation product. Carrier supplied to batch meter according to
By adjusting the gas feed rate, the amount of powder fed into the barrel can be controlled.

Thus, by varying the carrier gas feed rate, stability in the amount of powder injected into the barrel is maintained. However, only if the gas mixture supplied to the detonation chamber contains a significant amount of inert gas, according to the applied coating direction, as is the case when the coating material consists of a low-melting metal, e.g. nickel. In this case, such changes in carrier gas feed rate do not affect the quality of the resulting coating. Yanghe uses refractory materials such as alumina as the coating material,
The explosive mixture is not mixed with an inert gas, which is supplied to the detonation chamber carrying the powdered coating material.

Changes in the feed rate of this gas can therefore cause changes in the temperature of the detonation product, which can affect the quality of the coating thus obtained. The aim of the invention is to obviate the above-mentioned drawbacks.

The present invention consists in providing a detonation coating device that improves the quality of the applied coating independently of the powder coating material; This was achieved by an improvement in the connection between the device and the powder feeder, which ensures stability of the amount of powder sprayed without changing the carrier gas feed rate.

This object of the invention provides a detonation chamber made in the form of a barrel with one end sealed, a spark plug mounted in the barrel, a mixed gas supply device, a powder supply device, a control device, and a device for controlling the amount of powder in the detonation product.

The mixed gas supply device includes a mixer communicating with the detonation chamber. The powder feeder includes a batch meter in communication with a carrier gas source by a valve. The batch meter has a feeder communicating with the detonation chamber. The control device is electrically connected to the spark plug, mixer valve and batch meter valve, respectively. A device for regulating the amount of powder in the detonation product has a powder detector mounted at the open end of the barrel and in electrical communication with the powder supply device. According to the invention, the batch meter has a feed hopper communicating with the feeder by a slide valve with an actuator connected through an inverter element to a device for controlling the amount of powder in the detonation product. include. Such a construction of a batch meter with a controlled sliding valve makes it possible to add powder from the feed hopper to the feeder if the amount of powder in the detonation product is less than the required value, thereby reducing the amount of powder in the feed hopper. It is possible to maintain a constant powder level (with minor deviations) and provide a constant carrier-gas path for transporting the powder particles and thus a constant amount of powder to the detonation chamber.

The absence of a threshold element in the electrical circuit connecting the actuator of the slide valve to the device for controlling the amount of powder in the detonation product prevents the powder supply device from changing in the amount of powder in the detonation chamber. Make it highly responsive. At the same time, an accidental drop in the detector signal that affects the level of powder in the feeder without affecting the amount of powder injected into the detonation chamber can cause a distinct quantitative change in the amount of powder. Can not. The apparatus for controlling the amount of powder injected into the detonation chamber as described above ensures a constant amount of powder in the powder batch without changing the feed rate of the carrier gas, so that the coate of the present invention The coating device can be used to apply coatings using any coating material.

The present invention will now be described with reference to special embodiments. The detonation coating device of the present invention includes a detonation chamber 1, a mixed gas supply device 2 communicating with the detonation chamber, a powder supply device 3 communicating with the detonation chamber, and connected to both supply devices. It consists of a control device 4 and a device 5 for controlling the amount of powder in the detonation product) which is electrically connected to the powder feed device 3.

The detonation chamber 1 is made in the shape of a barrel with one end sealed, and a spark plug 6 for starting detonation in the detonation chamber 1 is installed inside the barrel. 6 is electrically connected to the control device 4.

The mixed gas supply device 2 is connected to the fuel source 1 by means of valves 8, 9, 10.
1, a mixer 7 communicating with an oxidant source 12 and an inert gas source 13, respectively. Acetylene, oxygen, and nitrogen can be used as the fuel, oxidizer, and inert gas, respectively. The mixer 7 is connected to the detonation chamber through a coil tube 14 to protect the mixer 7 from backsurge, that is, to prevent detonation waves generated by an explosion in the detonation chamber 1 from being transmitted into the mixer 7. It communicates with 1. The powder feeder 3 includes a batch meter 15 having a feeder 16 and a feed hopper 17 located above the feeder 16 and communicating with the feeder 16 by a slide valve 18 .

Connecting pipes 19 and 20 are installed in the feeder 16, and the ends of these connecting pipes are introduced into the feeder 16. Connecting tube 19 is connected to a supply vibe line 21 which is connected to a source of inert gas.

This supply vibe line 21 is for feeding an inert gas to the batch meter 15, and the inert gas is used as a transport medium (carrier gas). The supply vibe line 21 is equipped with a valve 22 . A connecting pipe 20 communicates the feeder 16 with the detonation chamber 1, and a valve 22
When the feeder 16 is open, powder sent from the feeder 16 is injected into the detonation chamber.

The slide valve 18 has an electromagnet 23 whose magnetic core is connected to a valve 24 of the discharge hole of the hopper 17, which valve 24 is held in the closed position by a spring 25. The control device 4 includes a setting device in the form of an electromechanical or electronic main control. Control equipment. The station 4 is connected by a control circuit to the spark plug 6, to the valves 8, 9, 10 to the mixer 7 and to the valve 22 of the powder feeder 3. The device 5 for controlling the amount of powder in the detonation product incorporates a powder detector 26 mounted at the open end of the barrel and a signal converter 27 for converting the signal sent from the powder detector. I'm here.

Powder detector 26 is constructed in the form of a photodiode that responds to the radiation produced by the detonation products.

Other suitable devices may be used instead of the photodiode, such as a photoresistor. The signal converter 27 consists of a series circuit including an input signal power amplifier and an integrating circuit.

A coil of an electromagnet 23 is connected through an inverter 28 to the output terminal of the signal converter 27, which also serves as the output terminal of the device 5.

The electromagnet 23 ) functions as an actuator for the slide valve 18 . A DC power supply 29 serves as a power source for the devices 4 and 5.
use. Although what has been described above is a preferred embodiment of the device of the invention, some parts may be made in various other forms.
can be done.

For example, the batch meter of the powder supply device 3 has a feeder 16 and a supply hopper 17 arranged side by side and communicated with each other through a pipe 30, as shown in FIG.
an electromagnet 23 capable of controlling the inlet opening of the tube 30 placed therein;
A sliding bail (Slld) connected to the magnetic core of
ingvale) Can be made into a lid with 18 valves. Apart from the connecting pipe 19 that reaches into the feeder 16, a connecting pipe 31 that reaches into the hopper 17 is also connected to the supply vibe line 21, and this connecting pipe 31 is connected to the valve 24.
When open, the carrier gas is fed into the hopper 17 which is used to transport the powder from the supply hopper 17 to the feeder 16. Hereinafter, the operation of the above apparatus will be explained when the coating method of the present invention is carried out without the presence of an inert gas in the mixed gas supplied into the detonation chamber.

This is possible, for example, when the coating material is alumina. In other cases the operation of the device may be more complicated, but in this particular case this is not an issue. When the power source 29 is switched on (FIG. 1),
The control device begins sending electrical signals to operate the controlled machines associated with it in a predetermined sequence.

In this case, valves 8 and 9 are first opened to transport fuel and oxidizer from fuel source 11 and oxidizer source 12 respectively into mixer 7 from where the explosive mixture formed in mixer 7 is passed through coiled tube 14. and is sent to detonation chamber 1. Valve 22 is then opened to allow inert gas to be delivered from inert gas source 13. This inert gas is connected to the connecting pipe 19,
Feeder 16 and connecting pipe 20 of batch meter 15
A quantity of powdered coating material is entrained from the feeder 16 to the detonation chamber 1 through the feeder 16 . The amount of powder thus conveyed depends on the nature of the powder, the pressure of the inert gas and the time the valve 22 is open. While valve 10 is open, valves 8, 9, 22 are closed and inert gas source 1
3 into the mixer 7 causes the remaining explosive mixture from the mixer 7 to be expelled into the explosion chamber 1. After that, the spark plug 6 is placed inside the explosion chamber 1.
Detonation is started by The detonation product, carrying the powder particles of the coating material heated by the detonation, flows at a high velocity from the plug in the direction of part C. The powder particles impacting the surface of part C bond to the surface and form a coating layer. Thereafter, after purging the detonation chamber with an inert gas passed into the detonation chamber through valve 10, mixer 7 and coiled tube 14, valve 10 is closed and the operating cycle is repeated again. At the moment when the power source 29 is switched on, the signal from the powder detector 26 is at a minimum magnitude and therefore the signal occurring at the output of the signal converter 27 is also of low value, and this signal is transferred to the inverter. 28, resulting in a maximum signal at the output of the inverter 28,
This signal is sent to the coil of electromagnet 23 to move valve 24 downward.

As a result, the powder is transferred from the supply hopper 17 to the feeder 16.
Sent inside. When a two-phase flow (of powder and gaseous detonation products) is flowing from the barrel, a powder detector measures the brightness of the two-phase flow, which is dependent on the amount of powder contained in this two-phase flow. is measured.

When the amount of powder in the detonation product is sufficient, the signal from the detector 26 is amplified in the converter 27 to reach a maximum value, and the signal at the output of the inverter 28 corresponds to a minimum value. arise. As a result, the electromagnet 23 of the slide valve 18 is deenergized and, under the action of the spring 25, the valve 24 closes, blocking the flow of powder from the hopper 17 into the feeder 16. If the amount of powder in the detonation product stream does not reach the predetermined value, the valve 24 remains open) and powder flows from the hopper 17 into the feeder 16 until the powder content in the detonation product reaches the predetermined value. do.

During operation of the device, as the level of powder in the feeder 16 decreases, resulting in a decrease in the amount of powder in the detonation product, the brightness of the detonation product stream also decreases;
At the same time as the signal at the output of the signal converter becomes smaller, the signal at the output of the inverter 18 reaches its maximum value, which activates the electromagnet 23 to open the valve 24 and transfer the powder to the hopper 1.
7 into the feeder 16 to fill the feeder 16 with powder to the required level.

In this way, the amount of powder coating material injected into the detonation chamber is automatically stabilized. This high degree of stability of the amount of powder in the detonation product stream ensures a high quality coating characterized by uniform physical properties. The operation of an apparatus with a batch meter, as shown in FIG. transported. That is, the hopper 1 passes through the valve 22 and the connecting pipe 31.
The inert gas flowing into 7 entrains the powder and transports it through tube 30 to feeder 16. Having thus described particular embodiments of the invention, various modifications will become apparent to those skilled in the art.

Accordingly, the present invention may be practiced in various ways other than those described above within the scope of the claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a functional diagram of the device according to the invention, and FIG. 2 is a schematic diagram showing one variant of the batch meter incorporated into the device according to the invention.

In the figure, 1 is a detonation chamber, 2 is a mixed gas supply/supply device, 3 is a powder supply device, 4 is a control device, 5 is a device for controlling the amount of powder contained in the detonation product,
6 is a spark plug, 7 is a mixer, 8 is a mixer valve, 9 is a mixer valve, 10 is a mixer valve, 15 is a batch meter, 16 is a feeder, 17 is a supply hopper, 18 is a slide valve, 22 is a batch meter valve , 26 is a powder detector, 2
8 is an inverter element.

Claims (1)

[Claims] 1 A detonation chamber 1 made in the shape of a barrel with one end sealed: a spark plug 6 installed in the barrel; a mixed gas supply device 2 including a mixer 7 communicating with the detonation chamber 1; a detonation chamber Powder feeding device 3 comprising a batch meter 15 having a feeder 16 in communication with 1, the batch meter communicating with a source of carrier gas through a valve 22: a spark plug 6, a valve of a mixer 7; 8, 9, 10 and a control device 4 electrically connected respectively to the valve 22 of the batch meter 15: a device 5 for controlling the amount of powder contained in the detonation product, the device 5 being electrically connected to the valve 22 of the batch meter 15; a device 5 having a detector 26 mounted at the end and electrically connected to a powder supply device 3 for controlling the amount of powder contained in the detonation product. Detonation coating, characterized in that the batch meter 15 comprises a powder feed hopper 17 communicating with the feeder 16 through a slide valve 18 with an actuator connected to the device 5 by an inverter element 28. Device.