CN111549309A - Low-temperature high-speed flame spraying gun - Google Patents
Low-temperature high-speed flame spraying gun Download PDFInfo
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- CN111549309A CN111549309A CN202010481744.5A CN202010481744A CN111549309A CN 111549309 A CN111549309 A CN 111549309A CN 202010481744 A CN202010481744 A CN 202010481744A CN 111549309 A CN111549309 A CN 111549309A
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
- C23C4/129—Flame spraying
Abstract
The invention discloses a low-temperature high-speed flame spraying gun. The outer gun body is internally provided with a combustion chamber. The head of the outer gun body is provided with a gun tube body through a middle connector. The middle connecting body is provided with a powder feeding nozzle. The inlet of the combustion chamber is sealed by a combustion chamber head cover, a central cone penetrates through the combustion chamber head cover, and a fuel nozzle is sleeved outside the central cone. A horn-shaped annular oxygen/fuel channel is formed between the fuel nozzle and the central cone body, and an annular primary nitrogen mixing straight channel is formed between the central cone head and the combustion chamber head cover. The head cover of the combustion chamber is provided with a spark plug. The tail part of the outer gun body is provided with an outer gun body tail cover. An oxygen inlet joint communicated with the oxygen/fuel channel is arranged on the tail cover of the outer gun body. The combustor head cover is provided with a fuel injection joint communicated with the oxygen/fuel channel. The outer gun body is provided with a nitrogen inlet joint communicated with the primary nitrogen mixing straight channel and the secondary nitrogen injection eccentric hole. The invention can obtain high flame flow speed, and can make the flame flow temperature in a reasonable low temperature range and be greatly adjustable.
Description
Technical Field
The invention relates to a low-temperature high-speed flame spraying gun, and belongs to the technical field of high-speed flame spraying.
Background
High-speed flame spraying is a thermal spraying process in which a spraying material (wire or powder) is heated (to a molten or semi-molten state) and accelerated (to a supersonic state) by using high-temperature high-speed combustion gas generated by combustion of gas or liquid fuel and high-pressure oxygen or air, and is sprayed onto the surface of a workpiece to form a coating. It was first introduced by BrowningEngineering in the united states in the early 80 s of the last century, has undergone over 30 years of development, and is widely used for the preparation of various surface coatings.
The high-speed oxygen-fuel supersonic flame spraying (HVOF) in the high-speed flame spraying has extremely high flame flow speed (the maximum particle speed can reach 1000m/s or even higher) and flame flow temperature (about 2400 ℃), so that the advantages of preparing metal, ceramic and composite coatings are quite obvious, and the bonding strength of the coatings is high. However, it can be found from practical implementation that HVOF has the following disadvantages: HVOF changes the speed and temperature of combustion gas by adjusting the mass flow ratio (or called oxygen-fuel ratio) of oxygen and fuel in the implementation of spraying, but the process window is usually narrow, the adjustable range of the oxygen-fuel ratio is small, the low oxygen-fuel ratio is difficult to ensure the sufficient combustion of the fuel, and even combustion products which are not beneficial to the quality of a coating can be generated; the high oxygen-fuel ratio ensures the sufficient combustion of the fuel to a certain extent, but the residual active oxygen in the combustion gas can cause the coating material to suffer serious oxidation, and particularly when the metal and the composite material thereof are sprayed, the coating material is easy to oxidize, and the deposition quality of the coating is poor; meanwhile, the higher deposition temperature easily causes residual tensile stress in the coating structure, which is not beneficial to improving the properties of the coating such as bonding strength, fatigue resistance, wear resistance, stress corrosion resistance and the like. Therefore, the flame flow temperature, velocity and active oxygen content of HVOF during spraying need to be well controlled to avoid the aggravated oxidation of the material due to overhigh heating temperature, and the flight velocity of the spraying powder needs to be further improved to greatly improve the key comprehensive performance indexes such as the bonding strength of the coating, but the actual control is very difficult.
The advent of cold spray technology in the last 90 s of the century has improved the quality of some metal coatings to some extent. Cold spraying is generally carried out by heating high-pressure nitrogen, argon or helium gas to some extent (generally not more than 1200 ℃) by an electric heating method, and spraying the powder through a nozzle at a high speed to form a supersonic gas flow, so that the sprayed powder is sprayed onto the surface of a workpiece at a temperature far below the melting point of the sprayed powder and an extremely high speed to form a coating. The deposition rate of the spray powder in cold spraying needs to be higher than the critical rate of the spray powder to complete reliable deposition, so that the cold spraying has higher requirements on materials, not all metal materials are suitable for cold spraying, the requirements on the types, pressure and the like of gas are also higher in cold spraying, the conversion efficiency of electric energy to gas heat energy is limited, the energy consumption of a gas heating device is higher, and the preparation cost is correspondingly increased.
Therefore, a spraying technical scheme is designed, so that the high flame flow speed can be kept in the spraying process, and meanwhile, the flame flow temperature is in a reasonable low-temperature range approximately between cold spraying and HVOF and can be greatly adjusted, so that the spraying device can be suitable for wider coating materials, has better coating deposition effect and is a direction which is urgently needed to be deeply excavated at present.
Disclosure of Invention
The invention aims to provide a low-temperature high-speed flame spraying gun, which atomizes a mixture of oxygen and fuel by high-pressure primary nitrogen and reduces the combustion temperature, and then further reduces the temperature and increases the speed of combustion gas generated by combustion in a combustion chamber by high-pressure secondary nitrogen, so that the flame flow temperature is in a reasonable low-temperature range and can be controlled and adjusted greatly while the high flame flow speed is obtained, the low-temperature high-speed flame spraying gun is suitable for wider coating materials, and the coating deposition effect is good.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a high-speed flame spraying rifle of low temperature which characterized in that: it includes the outer rifle body, wherein: a combustion chamber with a contraction and expansion structure is arranged in the through cavity of the outer gun body; the head of the outer gun body is provided with a gun tube body through an intermediate connector, and an outlet of a combustion chamber forming a combustion cavity is communicated with a flame flow straight channel of the gun tube body through an intermediate connecting cavity of the intermediate connector; the middle connecting body is provided with a powder feeding nozzle, and a spraying powder channel formed by the powder feeding nozzle is communicated with the middle connecting cavity; the inlet of the combustion chamber is sealed by a combustion chamber head cover, a central cone penetrates through the combustion chamber head cover, a fuel nozzle is sleeved outside the central cone, a horn-shaped annular oxygen/fuel channel is formed between the fuel nozzle and the cone body of the central cone, an annular primary nitrogen mixing straight channel is formed between the cone head of the central cone and the combustion chamber head cover and is communicated with the oxygen/fuel channel and the combustion chamber, a spark plug is arranged on the combustion chamber head cover, and a spark ignition port of the spark plug is communicated with the combustion chamber; the tail part of the outer gun body is provided with an outer gun body tail cover which covers the combustion chamber head cover, the fuel nozzle and the central cone; an oxygen inlet joint is arranged on the tail cover of the outer gun body and is communicated with the oxygen/fuel channel through an oxygen channel; the head cover of the combustion chamber is provided with a fuel injection joint which penetrates through the tail cover of the outer gun body, and the fuel injection joint is communicated with the oxygen/fuel channel through a fuel channel; the outer gun body is provided with a nitrogen inlet joint which is communicated with a primary nitrogen mixing straight channel through a primary nitrogen channel and communicated with a secondary nitrogen injection eccentric hole on the combustion chamber through a secondary nitrogen channel.
The invention has the advantages that:
1. according to the invention, high-pressure primary nitrogen is mixed into the mixture of oxygen and fuel, secondary atomization and combustion temperature reduction are realized on the mixture of oxygen and fuel, and the risk of high-temperature burning loss of the thin-wall part of the central cone and the fuel nozzle close to the combustion chamber is reduced. Tests show that when fuel and oxygen are combusted, the cone head of the central cone and the thin-wall part of the fuel nozzle close to the combustion chamber are easily burnt and damaged, and even if high-temperature materials are used for manufacturing, the high-temperature of combustion gas is difficult to bear.
2. According to the invention, high-pressure secondary nitrogen is tangentially sprayed into the combustion chamber along the wall surface of the combustion chamber, so that on one hand, the secondary nitrogen injected into the combustion chamber can flow close to the inner wall of the combustion chamber to form a gas film cooling effect, the contact between high-temperature combustion gas and the wall surface of the combustion chamber is effectively blocked, the combustion chamber is prevented from being subjected to high-temperature test, on the other hand, the combustion gas generated by combustion of a mixture of oxygen and fuel in the combustion chamber has the effects of further cooling and accelerating, and the flow demand of external cooling liquid on the refrigeration of the spray gun is reduced. The tangential injection also reduces the impact of secondary nitrogen on the combustion gas to a certain extent, so that the secondary nitrogen can be smoothly mixed into the combustion gas to realize secondary temperature reduction.
3. The invention ensures the full atomization of fuel and the stable combustion in a combustion chamber based on a flow structure formed by sequentially injecting primary nitrogen and secondary nitrogen step by step, so that the invention can reliably work under the working condition of inputting oxygen and nitrogen with the high pressure range of 1.5-5 MPa.
4. The invention makes up the defects of the prior high-speed flame spraying and cold spraying technologies and widens the application range of the low-temperature high-speed flame spraying technology. The invention can inject a large amount of nitrogen, can effectively reduce the temperature of the flame flow, and can also play a role in increasing the gas flow and further improving the speed of the flame flow, and the maximum particle speed can reach 1000m/s or more, so that the spraying powder (spraying material) can be reliably deposited on the surface of a workpiece to form a high-quality coating under the conditions that the temperature is far below the melting point temperature or is close to the melting point temperature, even is slightly above the melting point temperature, the problem that the temperature of the flame flow is not matched with the heating requirement of the spraying material in the prior thermal spraying technology is solved, the invention is suitable for wider coating materials, and particularly can produce the effects of reducing the oxidation degree of the spraying powder, improving the bonding strength of the coating, improving the residual stress distribution of the coating and the like when the temperature is far below or close to the melting.
Drawings
FIG. 1 is a schematic view of a preferred embodiment of the low temperature high velocity flame spray gun of the present invention.
Fig. 2 is a schematic sectional view taken along line a-a of fig. 1.
Fig. 3 is an enlarged schematic view of part C of fig. 1.
Fig. 4 is a schematic structural view (cross-sectional view) of the combustion chamber.
Fig. 5 is a schematic sectional view taken along line B-B of fig. 4.
Detailed Description
As shown in fig. 1 to 5, the low-temperature high-speed flame spraying gun of the present invention includes an outer gun body 40, wherein: a combustion chamber 20 with a contraction and expansion structure is arranged in the through cavity of the outer gun body 40; the head of the outer gun body 40 is mounted with the gun tube body 70 through the intermediate connection body 30, and the outlet 240 of the combustion chamber 20 forming the combustion chamber 280 communicates with the flame flow straight passage 720 of the gun tube body 70 through the intermediate connection chamber 310 of the intermediate connection body 30; the intermediate connecting body 30 is provided with a powder feeding nozzle 60 for feeding the spraying powder, and a spraying powder passage 610 formed by the powder feeding nozzle 60 is communicated with the intermediate connecting cavity 310; the inlet 250 of the combustion chamber 20 is sealed by a combustion chamber head cover 100, a central cone 10 is arranged on the combustion chamber head cover 100 in a penetrating manner, a fuel nozzle 90 is sleeved outside the central cone 10, the fuel nozzle 90 is arranged between the central cone 10 and the combustion chamber head cover 100, a horn-shaped annular oxygen/fuel channel 510 is formed between the fuel nozzle 90 and a cone body 101 of the central cone 10, an annular primary nitrogen mixing straight channel 530 is formed between a cone head 102 of the central cone 10 and the combustion chamber head cover 100, the primary nitrogen mixing straight channel 530 is respectively communicated with the oxygen/fuel channel 510 and a combustion cavity 280, a spark plug 80 is arranged on the combustion chamber head cover 100, and a spark ignition port 810 of the spark plug 80 is communicated with the combustion cavity 280; the tail part of the outer gun body 40 is provided with an outer gun body tail cover 50 which covers the combustion chamber head cover 100, the fuel nozzle 90 and the central cone 10; an oxygen inlet connector 601 is arranged on the outer gun body tail cover 50, the oxygen inlet connector 601 is connected with an external oxygen supply device (known device), and the oxygen inlet connector 601 is communicated with the oxygen/fuel channel 510 through an oxygen channel; the combustion chamber head cover 100 is provided with a fuel injection joint 611 penetrating through the outer gun body tail cover 50, the fuel injection joint 611 is connected with an external fuel supply device (known device), and the fuel injection joint 611 is communicated with the oxygen/fuel channel 510 through a fuel channel; the outer gun body 40 is provided with a nitrogen gas inlet joint 621, the nitrogen gas inlet joint 621 is connected with an external nitrogen gas supply device (known device), and the nitrogen gas inlet joint 621 is communicated with the primary nitrogen gas mixing straight channel 530 through a primary nitrogen gas channel and is communicated with the secondary nitrogen gas injection eccentric hole 260 on the combustion chamber 20 through a secondary nitrogen gas channel.
In practical design, the oxygen passage is composed of a first oxygen passage 501 on the outer gun body tail cover 50 and a second oxygen passage 910 on the fuel nozzle 90, wherein: the oxygen inlet joint 601 communicates with the first oxygen passage 501. The fuel passages are formed by the first fuel passage 110 on the combustion chamber head cover 100 and the second fuel passage 920 on the fuel nozzle 90, wherein: the fuel injection fitting 611 communicates with the first fuel passage 110. The primary nitrogen passage is constituted by the first primary nitrogen passage 120 on the combustion chamber head cover 100 and the second primary nitrogen passage 520 interposed between the fuel nozzle 90 and the combustion chamber head cover 100. The secondary nitrogen passage is located between the combustion chamber 20 and the outer gun body 40, in other words, the gap between the combustion chamber 20 and the outer gun body 40 is the secondary nitrogen passage 130.
In the present invention:
the second oxygen channel 910 of the fuel nozzle 90 is used to introduce a large amount of oxygen, and the second oxygen channel 910 can be designed reasonably according to actual requirements without limitation. As shown in fig. 1, the second oxygen passage 910 may be designed as a plurality of through holes uniformly distributed about a central axis of the fuel nozzle 90, and the first oxygen passage 501 communicates with the oxygen/fuel passage 510 through the plurality of through holes. The cross-sectional area of the first oxygen passage 501 is much larger than the cross-sectional area of the second oxygen passage 910, and the cross-sectional area of the second oxygen passage 910 is much larger than the smallest annular cross-sectional area of the oxygen/fuel passage 510.
The outlet of the second oxygen channel 910 and the outlet of the second fuel channel 920 are located at the position of the body 101 of the central cone 10, and the outlet of the second fuel channel 920 is close to the head 102 of the central cone 10 compared to the outlet of the second oxygen channel 910.
As shown in fig. 3, the cross-sectional area of the first fuel passage 110 is larger than that of the second fuel passage 920, so that the fuel flow rate is limited by the cross-sectional area of the second fuel passage 920, and the fuel is uniformly and stably mixed into the oxygen.
The ratio of the minimum annular cross-sectional area of the secondary nitrogen channel 520 to the minimum annular cross-sectional area of the oxygen/fuel channel 510 is 0.5 to 3.0, so that the temperature of oxygen and fuel during combustion can be reduced by mixing nitrogen into oxygen, and further, the risk of high-temperature burning loss of the thin-walled part of the fuel nozzle 90 and the conical head 102 of the center cone 10, which is close to the combustion chamber 20, is reduced.
In addition, in the present invention, the trumpet-shaped annular design of the oxygen/fuel channel 510 can achieve the purpose of accelerating the air flow and the purpose of atomizing the fuel in a cone shape, and the atomization quality is improved, the linear channel design of the primary nitrogen mixing straight channel 530 enables the mixture mixed with the primary nitrogen, the oxygen and the fuel sprayed by the primary nitrogen mixing straight channel to be reliably ignited by the spark generated by the spark ignition port 810 of the spark plug 80 and to flow at a high speed to form a low-speed backflow zone at the front end of the cone head 102, and the low-speed backflow zone has the function of flame stabilization, thereby improving the reliability and stability of the combustion of the lance.
As shown in fig. 4, the combustor 20 includes a combustion section 230, a connecting section 220, and an outlet section 210, wherein:
the outlet section 210 forms an outlet 240 with a diameter much smaller than that of the combustion section 230 and equal to the diameter of the intermediate connecting cavity 310 on the intermediate connecting body 30 and the diameter of the flame flow through passage 720 on the lance tube body 70;
at least one circle of the secondary nitrogen gas injection eccentric holes 260 are circumferentially provided at a position on the combustion section 230 near the inlet 250 (fig. 4 shows a case of two circles of the secondary nitrogen gas injection eccentric holes 260), and the secondary nitrogen gas injection eccentric holes 260 of each circle are communicated with each other through a groove (not shown) provided on an outer wall of the combustion section 230, wherein the secondary nitrogen gas injection eccentric holes 260 have the same deflection direction and are eccentrically provided with respect to a central axis of the combustion section 230, as shown in fig. 5, so that the secondary nitrogen gas fed from the secondary nitrogen gas injection eccentric holes 260 is injected tangentially along the wall surface of the combustion section 230. The number of the secondary nitrogen injection eccentric holes 260 in each circle is not limited, generally, the number of the secondary nitrogen injection eccentric holes 260 in each circle is 10-20, the total number of the secondary nitrogen injection eccentric holes 260 in each circle is 20-40, and the aperture of each secondary nitrogen injection eccentric hole 260 can be reasonably designed according to actual requirements, and can be generally designed to be 0.2 mm-0.5 mm.
Referring to fig. 1 and 2, the barrel body 70 includes an inner barrel 72 forming a flame flow through passage 720, a rear end of the inner barrel 72 is mounted on the intermediate connecting body 30, a barrel outer sleeve 71 is sleeved outside the inner barrel 72, and a rear end of the barrel outer sleeve 71 is fixed to the intermediate connecting body 30 by a barrel fixing cap 74.
Further, a cooling liquid return sleeve 73 is disposed between the barrel outer sleeve 71 and the inner barrel 72, a cooling liquid inlet connector 631 is mounted on the intermediate connecting body 30, a cooling liquid outlet connector 632 is mounted on the outer barrel 40, the cooling liquid inlet connector 631 and the cooling liquid outlet connector 632 are connected to an external cooling liquid supply device (known device), the cooling liquid inlet connector 631 is communicated with the cooling liquid outlet connector 632 through a liquid inlet channel 731 between the barrel outer sleeve 71 and the cooling liquid return sleeve 73, a through hole 730 on the cooling liquid return sleeve 73, a return channel 731 between the cooling liquid return sleeve 73 and the inner barrel 72, an intermediate channel (not shown in the figure) on the intermediate connecting body 30, and a liquid outlet channel 732 between the combustion chamber 20 and the outer barrel 40, wherein the liquid outlet channel 732 covers the outlet section 210 of the combustion chamber 20, the connecting section 220, and the front portion of the combustion section 230 (i.e. the portion near the connecting section 220), the secondary nitrogen passage 130 covers the remaining portion of the combustion section 230 except the front portion, that is, the present invention cools the combustion chamber 20 by using a combination of secondary nitrogen and cooling liquid, and the intermediate connecting body 30 and the barrel body 70 are cooled by using a cooling liquid.
As shown in fig. 1, 2 and 4, a groove 270 is convexly formed on the outer wall of the combustion section 230 of the combustion chamber 20, and an O-ring 415 for isolating the liquid outlet channel 732 from the secondary nitrogen channel 130 is installed in the groove 270.
In addition to the O-ring 415, the low-temperature high-speed flame spraying gun of the present invention is provided with O-rings at other positions. For example, referring to FIG. 1, an O-ring 411 is installed between the fuel nozzle 90 and the outer barrel tail cap 50, an O-ring 413 is installed between the fuel nozzle 90 and the combustion chamber head cover 100, 414, an O-ring 413 is interposed between the oxygen passage and the fuel passage to isolate oxygen and fuel, an O-ring 414 is interposed between the fuel passage and the primary nitrogen passage to isolate fuel and primary nitrogen, an O-ring 412 is installed between the combustion chamber head cover 100 and the tail of the outer gun body 40, an O-ring 416 is installed between the head of the outer gun body 40 and the intermediate connector 30, an O-ring 417 is installed between the intermediate connector 30 and the outlet section 210 of the combustion chamber 20, an O-ring 418 is installed between the tail of the inner gun tube 72 and the intermediate connector 30, an O-ring 419 is installed between the barrel outer sleeve 71 and the intermediate connector 30, and an O-ring 420 is installed between the head of the inner gun tube 72 and the barrel outer sleeve 71.
In the invention, each O-shaped sealing ring is used for ensuring the sealing performance and can be made of rubber materials.
As shown in fig. 1 and 2, the powder feeding nozzle 60 is disposed obliquely with respect to the central axis of the gun tube body 70, wherein: the included angle between the powder feeding nozzle 60 and the central axis of the gun barrel body 70 is 50-75 degrees; the intermediate connecting body 30 is uniformly provided with 2-4 powder feeding nozzles 60 along the circumference of the intermediate connecting body, and the number of the powder feeding nozzles 60 is not limited.
As shown in fig. 1 and 2, the ignition plug 80 is disposed obliquely with respect to the central axis of the center cone 10 so that a spark generated from a spark ignition port 810 of the ignition plug 80 can ignite a mixture (i.e., nitrogen-oxygen-fuel mixture) mixed with primary nitrogen, oxygen and fuel ejected from the primary nitrogen mixing straight passage 530. One spark plug 80 is shown in fig. 1, and the number of spark plugs 80 may be one.
Referring to FIG. 1, center cone 10 is secured to fuel nozzle 90 by a retaining nut 104 mounted on its own cone tail 103.
In the present invention, the number of the nitrogen gas inlet fittings 621 installed on the outer gun body 40 is one or two, wherein:
when the number of the nitrogen inlet joints 621 is one, the nitrogen inlet joints 621 are simultaneously communicated with the primary nitrogen channel and the secondary nitrogen channel, the primary nitrogen channel is communicated with the secondary nitrogen channel, and the nitrogen inlet joints 621 are communicated with the first primary nitrogen channel 120;
when the number of the nitrogen gas inlet joints 621 is two, one nitrogen gas inlet joint 621 communicates with the primary nitrogen gas channel and only this nitrogen gas inlet joint 621 communicates with the first primary nitrogen gas channel 120, the other nitrogen gas inlet joint 621 communicates with the secondary nitrogen gas channel, and the primary nitrogen gas channel and the secondary nitrogen gas channel are isolated from each other.
Fig. 1 shows the situation where the primary nitrogen gas and the secondary nitrogen gas are injected through the same nitrogen gas inlet joint 621, in this case, the injection pressures of the primary nitrogen gas and the secondary nitrogen gas are kept the same, the injection flow ratio of the primary nitrogen gas and the secondary nitrogen gas can be kept relatively stable (or has small variation), and the controllability is good. Of course, in practical design, the primary nitrogen and the secondary nitrogen can be injected through a nitrogen inlet joint 621 respectively, that is, the primary nitrogen channel and the secondary nitrogen channel are not communicated and are arranged separately from each other, specifically: two nitrogen gas inlet joints 621 are installed on the outer gun body 40, both of the two nitrogen gas inlet joints 621 are connected to an external nitrogen gas supply device (known device), one nitrogen gas inlet joint 621 is communicated with the primary nitrogen gas mixing straight channel 530 through a primary nitrogen gas channel, and the other nitrogen gas inlet joint 621 is communicated with the secondary nitrogen gas injection eccentric hole 260 on the combustion chamber 20 through a secondary nitrogen gas channel. At this time, the primary nitrogen gas passage is also composed of the first primary nitrogen gas passage 120 of the combustion chamber head cover 100 and the second primary nitrogen gas passage 520 interposed between the fuel nozzle 90 and the combustion chamber head cover 100, and the secondary nitrogen gas passage is also interposed between the combustion chamber 20 and the outer gun body 40. However, the structure design enables the primary nitrogen and the secondary nitrogen to be injected respectively and independently and to be isolated from each other, namely the injection pressure of the primary nitrogen and the injection pressure of the secondary nitrogen can be controlled independently, the injection flow rates of the primary nitrogen and the secondary nitrogen can be controlled independently, and the injection flow rates of the primary nitrogen and the secondary nitrogen can be adjusted in a large range.
In the present invention, the central cone 10 includes a cone head 102 and a cone tail 103, the cone head 102 is connected to the cone tail 103 through a cone body 101, and the whole central cone 10 gradually increases from the cone tail 103 to the cone head 102 and is trumpet-shaped, as shown in fig. 1 to 3.
In the present invention, the structure of the fuel nozzle 90 can be designed reasonably according to actual conditions, and is not limited.
The spark plug 80, the powder feeding nozzle 60, and the like are conventional in the art.
In the invention, the injected oxygen is high-pressure oxygen, and the injected primary nitrogen and secondary nitrogen are both high-pressure nitrogen, and the pressure ranges of the primary nitrogen and the secondary nitrogen are both between 1.5MPa and 5 MPa.
In the present invention, the fuel is preferably a liquid fuel (e.g., kerosene), and a gaseous fuel (e.g., propane, natural gas) may also be used.
The working process of the invention is as follows:
high-pressure oxygen is fed from the oxygen inlet joint 601, so that the high-pressure oxygen enters the oxygen/fuel channel 510 through the oxygen channel and is mixed with the fuel injected from the fuel injection joint 611 and entering the oxygen/fuel channel 510 through the fuel channel, then the mixture of the oxygen and the fuel is accelerated and blended through the trumpet-shaped annular oxygen/fuel channel 510 to complete primary atomization, and is intersected with the high-pressure primary nitrogen fed from the nitrogen inlet joint 621 and entering the primary nitrogen mixing straight channel 530 through the primary nitrogen channel in the primary nitrogen mixing straight channel 530, the primary nitrogen performs secondary atomization, temperature reduction (to some extent, acceleration effect) and blending on the mixture of the oxygen and the fuel, so that the mixture (nitrogen-oxygen fuel mixture) mixed with the primary nitrogen, the oxygen and the fuel is injected into the inlet of the combustion section 230 of the combustion chamber 20 at a high speed through the primary nitrogen mixing straight channel 530, and is ignited by a spark generated by the spark plug 80, the nitrogen-oxygen-fuel mixture is ignited, and while combustion gas is generated by combustion, the combustion gas is further cooled and the flow of the combustion gas is increased by the action of high-pressure secondary nitrogen which is fed from the nitrogen inlet joint 621 and is tangentially sprayed into the combustion section 230 along the wall surface of the combustion chamber 20 through the secondary nitrogen channel and the secondary nitrogen injection eccentric hole 260, further, the combustion gas is further accelerated by the contraction and expansion type structure of the combustion chamber 20, so that the combustion gas is ejected from the outlet section 210 (outlet 240) of the combustion chamber 20 at a high speed, and meets the spray powder fed through the powder feeding nozzle 60 while passing through the intermediate connection chamber 310, so that the spray powder is heated and accelerated by the low-temperature combustion gas and finally delivered through the flame flow straight passage 720 of the gun tube body 70, and is sprayed at high speed toward the surface of the workpiece to deposit a high-quality coating.
The invention has the advantages that:
after the mixture of oxygen and fuel is atomized by the high-pressure primary nitrogen and the combustion temperature is reduced, the combustion gas generated by combustion is further cooled and accelerated in the combustion chamber by the high-pressure secondary nitrogen, so that the flame flow temperature is in a reasonable low-temperature range and can be greatly controlled and adjusted while the high flame flow speed is obtained, the coating material is suitable for wider coating materials, and the coating deposition effect is good.
The above description is of the preferred embodiment of the present invention and the technical principles applied thereto, and it will be apparent to those skilled in the art that any changes and modifications based on the equivalent changes and simple substitutions of the technical solutions of the present invention are within the protection scope of the present invention without departing from the spirit and scope of the present invention.
Claims (10)
1. The utility model provides a high-speed flame spraying rifle of low temperature which characterized in that: it includes the outer rifle body, wherein: a combustion chamber with a contraction and expansion structure is arranged in the through cavity of the outer gun body; the head of the outer gun body is provided with a gun tube body through an intermediate connector, and an outlet of a combustion chamber forming a combustion cavity is communicated with a flame flow straight channel of the gun tube body through an intermediate connecting cavity of the intermediate connector; the middle connecting body is provided with a powder feeding nozzle, and a spraying powder channel formed by the powder feeding nozzle is communicated with the middle connecting cavity; the inlet of the combustion chamber is sealed by a combustion chamber head cover, a central cone penetrates through the combustion chamber head cover, a fuel nozzle is sleeved outside the central cone, a horn-shaped annular oxygen/fuel channel is formed between the fuel nozzle and the cone body of the central cone, an annular primary nitrogen mixing straight channel is formed between the cone head of the central cone and the combustion chamber head cover and is communicated with the oxygen/fuel channel and the combustion chamber, a spark plug is arranged on the combustion chamber head cover, and a spark ignition port of the spark plug is communicated with the combustion chamber; the tail part of the outer gun body is provided with an outer gun body tail cover which covers the combustion chamber head cover, the fuel nozzle and the central cone; an oxygen inlet joint is arranged on the tail cover of the outer gun body and is communicated with the oxygen/fuel channel through an oxygen channel; the head cover of the combustion chamber is provided with a fuel injection joint which penetrates through the tail cover of the outer gun body, and the fuel injection joint is communicated with the oxygen/fuel channel through a fuel channel; the outer gun body is provided with a nitrogen inlet joint which is communicated with a primary nitrogen mixing straight channel through a primary nitrogen channel and communicated with a secondary nitrogen injection eccentric hole on the combustion chamber through a secondary nitrogen channel.
2. The low temperature high velocity flame spray gun of claim 1, wherein:
the oxygen passage is formed by a first oxygen passage on the outer gun body tail cover and a second oxygen passage on the fuel nozzle, wherein: the oxygen inlet joint is communicated with the first oxygen channel;
the fuel passage is formed by a first fuel passage on the combustion chamber head cover and a second fuel passage on the fuel nozzle, wherein: the fuel injection fitting is in communication with the first fuel passage;
the primary nitrogen channel is composed of a first primary nitrogen channel on the combustion chamber head cover and a second primary nitrogen channel between the fuel nozzle and the combustion chamber head cover;
the secondary nitrogen channel is arranged between the combustion chamber and the outer gun body.
3. A low temperature high velocity flame spray gun as claimed in claim 2, wherein:
the outlet of the second oxygen channel and the outlet of the second fuel channel are positioned at the cone body position of the central cone, and compared with the outlet of the second oxygen channel, the outlet of the second fuel channel is close to the cone head of the central cone;
the cross-sectional area of the first fuel passage is larger than the cross-sectional area of the second fuel passage;
the ratio of the minimum annular cross-sectional area of the second primary nitrogen channel to the minimum annular cross-sectional area of the oxygen/fuel channel is 0.5 to 3.0.
4. The low temperature high velocity flame spray gun of claim 1, wherein:
the combustion chamber comprises a combustion section, a connecting section and an outlet section, wherein:
the outlet section forms an outlet diameter which is far smaller than the diameter of the combustion section and is equal to the diameter of the intermediate connecting cavity on the intermediate connecting body and the diameter of the flame flow straight channel on the gun barrel body;
the combustion section is provided with at least one circle of secondary nitrogen injection eccentric holes along the circumference at the position close to the inlet, each circle of secondary nitrogen injection eccentric holes are communicated with each other through a groove arranged on the outer wall of the combustion section, the number of the secondary nitrogen injection eccentric holes in each circle is 10-20, the total number of the secondary nitrogen injection eccentric holes in each circle is 20-40, the aperture of each secondary nitrogen injection eccentric hole is 0.2-0.5 mm, and each secondary nitrogen injection eccentric hole is eccentrically arranged relative to the central axis of the combustion section, so that secondary nitrogen sent out from each secondary nitrogen injection eccentric hole is tangentially injected along the wall surface of the combustion section.
5. The low temperature high velocity flame spray gun of claim 4, wherein:
the gun barrel body is including forming the interior barrel of straight passageway of flame flow, the afterbody of interior barrel is installed on the intermediate junction body, interior barrel outside cover is equipped with the barrel outer tube, the afterbody of barrel outer tube pass through the barrel locking cap with the intermediate junction body is fixed.
6. The low temperature high velocity flame spray gun of claim 5, wherein:
the utility model discloses a combustion chamber, including barrel outer tube, cooling liquid backflow sleeve, cooling liquid inlet joint, cooling liquid backflow sleeve, barrel outer tube and interior barrel, be equipped with coolant liquid backflow sleeve between the barrel outer tube with interior barrel, install coolant liquid inlet joint on the intermediate junction body, the coolant liquid backflow sleeve on the outer barrel body goes out liquid joint, coolant liquid inlet joint through in inlet channel between barrel outer tube and the coolant liquid backflow sleeve, through-hole on the coolant liquid backflow sleeve, between coolant liquid backflow sleeve with interior barrel on the intermediate junction body intermediate channel and in the combustion chamber with go out liquid channel between the outer barrel and go out liquid joint intercommunication with the coolant liquid, wherein, go out liquid channel cover the combustion chamber export section the linkage segment with the front portion of combustion section, secondary nitrogen gas passageway covers the other parts of combustion section.
7. The low temperature high velocity flame spray gun of claim 6, wherein:
the outer wall of the combustion section of the combustion chamber is convexly provided with a groove, and an O-shaped sealing ring used for isolating the liquid outlet channel from the secondary nitrogen channel is arranged in the groove.
8. The low temperature high velocity flame spray gun of claim 1, wherein:
send the powder mouth for the axis slope setting of rifle body, wherein: the included angle between the powder feeding nozzle and the central axis of the gun tube body is 50-75 degrees; 2-4 powder feeding nozzles are uniformly distributed on the middle connecting body along the circumference of the middle connecting body;
the ignition plug is disposed obliquely with respect to a central axis of the center cone so that a spark generated from a spark ignition port of the ignition plug can ignite a mixture mixed with the primary nitrogen gas, the oxygen gas and the fuel, which is ejected from the primary nitrogen gas mixing straight passage.
9. The low temperature high velocity flame spray gun of claim 1, wherein:
the central cone is fixed with the fuel nozzle through a fixing nut arranged on the cone tail of the central cone.
10. The low temperature high velocity flame spray gun of any one of claims 1 to 9, wherein:
the number of the nitrogen gas inlet joints arranged on the outer gun body is one or two, wherein:
when the number of the nitrogen inlet joints is one, the nitrogen inlet joints are simultaneously communicated with the primary nitrogen channel and the secondary nitrogen channel, and the primary nitrogen channel is communicated with the secondary nitrogen channel;
when the number of the nitrogen inlet joints is two, the two nitrogen inlet joints are respectively communicated with the primary nitrogen channel and the secondary nitrogen channel, and the primary nitrogen channel and the secondary nitrogen channel are isolated from each other.
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| CN111549309B (en) | 2022-04-12 |
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