Efficient degreasing device for powder metallurgy injection molding blank

Abstract

The efficient degreasing device comprises a degreasing furnace, an exhaust pipe, a nitrogen conveying pipe and a multi-layer degreasing frame, a nitric acid storage tank is arranged on one side of the degreasing furnace, an adding pipe and a blow-down pipe are arranged on the top of the nitric acid storage tank, a liquid level instrument is arranged on one side wall of the nitric acid storage tank, and the nitrogen conveying pipe is connected with the liquid level instrument. The other side wall of the nitric acid storage tank is provided with a suction pipe extending into the nitric acid storage tank, the end of the suction pipe is connected with a suction tank, the suction tank is provided with a suction mechanism, the bottom of the suction tank is provided with a nitric acid guide pipe, the nitric acid guide pipe is sequentially provided with a discharge valve and a gas-liquid mixer, the gas-liquid mixer is communicated with a pressurizing pipe, and the pressurizing pipe is communicated with a pressurizing pump. A pressurizing pump is installed on the pressurizing pipe, an acid mist ejector communicated with the nitric acid guide pipe is arranged in the debinding furnace, and a driver in transmission connection with the nitric acid ejector is installed at the bottom of the debinding furnace. The device has the advantages of being reasonable in structure, safe to use, stable in nitric acid conveying and high in degreasing efficiency.

Description

Technical Field

[0001] The utility model belongs to the technical field of powder metallurgy injection molding process, and in particular relates to a high-efficiency degreasing device for powder metallurgy injection molding blanks. Background Art

[0002] The metal injection molding process is to select metal powder and binder that meet the requirements of MIM, and then use appropriate methods to mix the powder and binder into a uniform feed at a certain temperature. After granulation, it is injection molded. The obtained molded blank is degreased and sintered to densify into the final product. Degreasing is to remove the binder in the molded blank by heating and decomposition. During the degreasing process, nitrogen is continuously introduced to exhaust the air in the furnace, and then catalytic materials are introduced into the furnace to catalytically decompose the binder in the molded blank at a certain temperature, thereby removing the binder in the molded blank. In the existing technology, the catalytic material used for catalytic degreasing is nitric acid, which has strong corrosiveness and volatility and is not easy to preserve. As a result, during the degreasing process of the powder metallurgy injection molding blank in the degreasing furnace, the container storing nitric acid often becomes blurred and unclear, and the nitric acid liquid level cannot be observed normally, and the nitric acid cannot be continuously and stably transported to the catalytic furnace, which will seriously affect the degreasing effect and efficiency. In addition, the volatilization of nitric acid will also affect the health of workers and pollute the working environment. At the same time, the acid feeding mechanism used in the prior art to enter the degreasing furnace only uses an air pump to pressurize and transport nitric acid, which cannot ensure that the nitric acid entering the degreasing furnace is evenly distributed, resulting in a relatively low catalytic degreasing efficiency of the injection molding blank. Therefore, it is an objective need to develop an efficient degreasing device for powder metallurgy injection molding blanks that has a reasonable structure, is safe to use, can achieve stable transportation of nitric acid, and can improve degreasing efficiency. Summary of the invention

[0003] The utility model aims to provide a high-efficiency degreasing device for powder metallurgy injection molding blanks which has a reasonable structure, is safe to use, can realize the stable conveying of nitric acid and can improve the degreasing efficiency.

[0004] The purpose of the utility model is achieved in this way, including a degreasing furnace, an exhaust pipe, a nitrogen delivery pipe and a multi-layer degreasing rack arranged in the degreasing furnace, a nitric acid storage tank is arranged on one side of the degreasing furnace, a adding pipe and a venting pipe are arranged on the top of the nitric acid storage tank, a control valve is installed on the adding pipe and the venting pipe, a liquid level meter is arranged on one side wall of the nitric acid storage tank, a suction pipe extending into the nitric acid storage tank is arranged on the other side wall of the nitric acid storage tank, the end of the suction pipe is connected with a suction tank, a suction mechanism is arranged on the suction tank, a nitric acid conduit is arranged at the bottom of the suction tank, a discharge valve and a gas-liquid mixer are arranged on the nitric acid conduit in sequence, a pressurizing pipe is connected to the gas-liquid mixer, a pressurizing pump is installed on the pressurizing pipe, an acid mist injector connected with the nitric acid conduit is arranged in the degreasing furnace, and a driver transmission-connected with the nitric acid injector is installed at the bottom of the degreasing furnace.

[0005] Compared with the existing technology, the advantages of the device are: first, the device optimizes the structure of nitric acid storage and transportation, and stores the catalyst nitric acid in a sealed nitric acid storage tank. On the one hand, it can solve the problem of nitric acid volatilization, improve the working environment, and improve the safety of use. On the other hand, it improves the convenience of use. When the metal injection molded blank needs to be degreased in the degreasing furnace, the nitric acid can be sucked into the suction tank by a suction pipe, and then mixed with compressed air through the gas-liquid mixer on the nitric acid conduit to form gaseous nitric acid, which is then introduced into the degreasing furnace. In this way, the gaseous nitric acid can be evenly and stably transported to the degreasing furnace to ensure the metal injection molding process. In addition, the liquid level meter provided in the device can detect the nitric acid capacity in the nitric acid storage tank in real time to ensure the normal supply of gaseous nitric acid in the degreasing furnace; secondly, the device optimizes the acid inlet structure in the degreasing furnace, and uses the driver to drive the acid mist injector to transport gaseous nitric acid to the bottom of the degreasing furnace in the form of rotary spray, so that the gaseous nitric acid can be evenly distributed in the degreasing furnace, so that the gaseous nitric acid can be evenly contacted with the metal injection molding blanks, which can effectively improve the degreasing efficiency. In summary, the device has the advantages of reasonable structure, safe use, stable nitric acid transportation and high degreasing efficiency, and is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0007] In the figure: 1-degreasing furnace, 11-exhaust pipe, 12-nitrogen delivery pipe, 13-degreasing rack, 14-injection box, 15-injection pipe, 16-rotating sleeve, 17-nitric acid branch pipe, 18-transmission shaft, 19-drive motor, 2-nitric acid storage tank, 21-addition pipe, 22-vent pipe, 23-liquid level meter, 24-suction pipe, 25-suction tank, 26-nitric acid conduit, 27-gas-liquid mixer, 28-pressurization pipe, 29-anti-collision plate, 210-negative pressure pipe, 211-manhole. DETAILED DESCRIPTION

[0008] The present invention is further described below in conjunction with the accompanying drawings, but the present invention is not limited in any way. Any changes or improvements made based on the teachings of the present invention belong to the protection scope of the present invention.

[0009] like Figure 1 As shown, the utility model includes a degreasing furnace 1, an exhaust pipe 11, a nitrogen delivery pipe 12 and a multi-layer degreasing rack 13 arranged in the degreasing furnace 1. The degreasing furnace 1 is a structure used in the prior art and is equipped with corresponding heating facilities. The exhaust pipe 11 and the nitrogen delivery pipe 12 are both provided with corresponding flow control valves. A nitric acid storage tank 2 is provided on one side of the degreasing furnace 1. A adding pipe 21 and a venting pipe 22 are provided on the top of the nitric acid storage tank 2. Control valves are installed on the adding pipe 21 and the venting pipe 22. A liquid level meter 23 is provided on one side wall of the nitric acid storage tank 2. The liquid level meter 23 is used to monitor the nitric acid capacity in the nitric acid storage tank 2. Preferably, the liquid level meter 23 can adopt a magnetic flap liquid level meter used in the prior art. The magnetic flap The liquid level meter can directly indicate the height of the nitric acid liquid level in the closed nitric acid storage tank 2. It has a simple structure, is intuitive and reliable, and is durable. A suction pipe 24 extending into the nitric acid storage tank 2 is arranged on the other side wall of the nitric acid storage tank 2, and the end of the suction pipe 24 is connected to a suction tank 25, and a suction mechanism is arranged on the suction tank 25. A nitric acid conduit 26 is arranged at the bottom of the suction tank 25, and a discharge valve and a gas-liquid mixer 27 are sequentially installed on the nitric acid conduit 26. A pressurizing pipe 28 is connected to the gas-liquid mixer 27, and a pressurizing pump is installed on the pressurizing pipe 28. An acid mist injector connected to the nitric acid conduit 26 is arranged in the degreasing furnace 1, and a driver transmission-connected to the nitric acid injector is installed at the bottom of the degreasing furnace 1.

[0010] The method of using the device is as follows: adding catalyst nitric acid into the nitric acid storage tank 2 through the adding tube 21, placing the metal injection molded blank on the degreasing rack 13 in the degreasing furnace 1, and then when degreasing the metal injection molded blank, opening the suction mechanism, transferring the nitric acid in the nitric acid storage tank 2 into the suction tank 25 through the suction tube 24, and then closing the suction mechanism, connecting the pressurizing tube 28 with the compressed air storage tank, opening the pressurizing pump, and simultaneously opening the discharge valve on the nitric acid conduit 26, the nitric acid in the suction tank 25 will enter the gas-liquid mixer 27 through the nitric acid. At this time, the compressed air enters the gas-liquid mixer 27, and can mix with the nitric acid to form gaseous nitric acid. The formed gaseous nitric acid enters the nitric acid injector through the nitric acid conduit 26. The gaseous nitric acid entering the nitric acid injector rotates under the driving action of the driver, and can evenly distribute the gaseous nitric acid into the degreasing furnace 1, so that the metal injection molded blank in the degreasing furnace 1 is fully and evenly mixed with the gaseous nitric acid. Uniform contact, at the same time, nitrogen is transported into the degreasing furnace 1 through the nitrogen delivery pipe 12. Under the protection of nitrogen, efficient degreasing of metal injection molded blanks can be achieved. The tail gas generated during the degreasing process can be discharged in time through the exhaust pipe 11. When the degreasing of the metal injection molded blanks is completed, the nitrogen and gaseous nitric acid are stopped from being transported into the degreasing furnace 1; the device stores the catalyst nitric acid in a sealed nitric acid storage tank 2. On the one hand, it can solve the problem of nitric acid volatilization, improve the working environment, and improve the safety of use. On the other hand, it improves the convenience of use, and can ensure uniform and stable delivery of gaseous acid to the degreasing furnace 1, ensuring the degreasing effect and degreasing efficiency of the injection molded blanks. At the same time, the device uses a driver to drive the acid mist injector to transport gaseous nitric acid to the bottom of the degreasing furnace 1 in a rotary spray manner, so that the gaseous nitric acid can be evenly distributed in the degreasing furnace 1, so that the gaseous nitric acid can be evenly contacted with the injection molded blanks, which can effectively improve the degreasing efficiency.

[0011] Furthermore, in order to increase the service life of the nitric acid storage tank 2 and prevent the nitric acid storage tank 2 from being corroded by nitric acid, a polyethylene lining layer is provided on the inner wall of the nitric acid storage tank 2. The polyethylene lining layer has good anti-corrosion performance and can reduce the corrosion of the nitric acid storage tank 2 by nitric acid.

[0012] Furthermore, in order to facilitate the addition of nitric acid in the nitric acid storage tank 2, the addition pipe 21 extends to the lower part of the nitric acid storage tank 2, and an anti-collision plate 29 is installed at the bottom of the nitric acid storage tank 2 below the addition pipe 21. The anti-collision plate 29 can prevent the added nitric acid from causing impact on the bottom of the nitric acid storage tank 2, which is beneficial to improving the service life of the nitric acid storage tank 2.

[0013] Furthermore, the suction mechanism includes a negative pressure pipe 210 and a suction pump installed on the negative pressure pipe 210. When degreasing is required, the suction pump can be used to transfer the nitric acid in the nitric acid storage tank 2 to the suction tank 25 for use in the degreasing furnace 1. When degreasing is not performed, the suction pump is turned off and the nitric acid is sealed and stored in the nitric acid storage tank 2.

[0014] Further, in order to achieve uniform distribution of nitric acid in the degreasing furnace 1, the nitric acid injector includes an internally hollow injection box 14, a plurality of injection pipes 15 are evenly installed on the top of the injection box 14, and two rotating sleeves 16 are symmetrically arranged at the bottom of the injection box 14. A nitric acid branch pipe 17 is rotatably installed in the rotating sleeve 16 through a sealed bearing, and the nitric acid branch pipe 17 is connected to the nitric acid conduit 26; the driver is a transmission shaft 18 and a driving motor 19, and the driving motor 19 is a device used in the prior art, and the finished product can be directly purchased according to the power requirement used, and the transmission shaft 18 drives It is installed at the bottom of the degreasing furnace 1, the upper end of the transmission shaft 18 is connected to the bottom center of the nitric acid injector, and the lower end of the transmission shaft 18 is transmission-connected to the output shaft of the driving motor 19. The driving motor 19 is installed below the degreasing furnace 1. When in use, the driving motor 19 drives the transmission shaft 18 to rotate, and the transmission shaft 18 drives the injection box 14 to rotate during the rotation. During the rotation of the injection box 14, the gaseous nitric acid that enters the rotating sleeve 16 from the nitric acid conduit 26 through the nitric acid branch pipe 17 will enter the injection box 14, and finally be injected into the degreasing furnace 1 through the multiple injection pipes 15.

[0015] Furthermore, in order to achieve uniform mixing of compressed air and nitric acid, the gas-liquid mixer 27 is a Venturi mixer.

[0016] Furthermore, in order to facilitate the inspection or cleaning of the interior of the nitric acid storage tank 2 , a manhole 211 is installed on the top of the nitric acid storage tank 2 .

Claims

1. A highly efficient degreasing device for powder metallurgy injection molding blanks, comprising a degreasing furnace (1), an exhaust pipe (11), a nitrogen delivery pipe (12), and a multi-layer degreasing rack (13) arranged in the degreasing furnace (1), characterized in that: A nitric acid storage tank (2) is provided on one side of the degreasing furnace (1), a feeding pipe (21) and a venting pipe (22) are provided on the top of the nitric acid storage tank (2), and control valves are installed on both the feeding pipe (21) and the venting pipe (22), a liquid level meter (23) is provided on one side wall of the nitric acid storage tank (2), and a suction pipe (24) extending into the nitric acid storage tank (2) is provided on the other side wall of the nitric acid storage tank (2), and the end of the suction pipe (24) is connected to a suction tank (25), and the suction tank A suction mechanism is arranged on (25), a nitric acid conduit (26) is arranged at the bottom of the suction tank (25), a discharge valve and a gas-liquid mixer (27) are sequentially installed on the nitric acid conduit (26), a pressurizing pipe (28) is connected to the gas-liquid mixer (27), a pressurizing pump is installed on the pressurizing pipe (28), an acid mist injector connected to the nitric acid conduit (26) is arranged in the degreasing furnace (1), and a driver connected to the nitric acid injector is installed at the bottom of the degreasing furnace (1).

2. The high-efficiency degreasing device for powder metallurgy injection molding blanks according to claim 1 is characterized in that: A polyethylene lining layer is provided on the inner wall of the nitric acid storage tank (2).

3. The high-efficiency degreasing device for powder metallurgy injection molding blanks according to claim 1 is characterized in that: The addition pipe (21) extends to the lower part of the nitric acid storage tank (2), and an anti-collision plate (29) is installed at the bottom of the nitric acid storage tank (2) below the addition pipe (21).

4. The high-efficiency degreasing device for powder metallurgy injection molding blanks according to claim 1 is characterized in that: The suction mechanism comprises a negative pressure tube (210) and a suction pump installed on the negative pressure tube (210).

5. The high-efficiency degreasing device for powder metallurgy injection molding blanks according to claim 1 is characterized in that: The nitric acid injector comprises an injection box (14) with a hollow interior, a plurality of injection pipes (15) are evenly arranged on the top of the injection box (14), two rotating sleeves (16) are symmetrically arranged on the bottom of the injection box (14), a nitric acid branch pipe (17) is rotatably installed in the rotating sleeve (16) via a sealed bearing, and the nitric acid branch pipe (17) is connected to a nitric acid conduit (26).

6. The high-efficiency degreasing device for powder metallurgy injection molding blanks according to claim 1 is characterized in that: The driver comprises a transmission shaft (18) and a driving motor (19); the transmission shaft (18) is drivingly mounted at the bottom of the degreasing furnace (1); the upper end of the transmission shaft (18) is connected to the bottom center of the nitric acid injector; the lower end of the transmission shaft (18) is drivingly connected to the output shaft of the driving motor (19); and the driving motor (19) is mounted below the degreasing furnace (1).

7. The high-efficiency degreasing device for powder metallurgy injection molding blanks according to claim 1 is characterized in that: The gas-liquid mixer (27) is a Venturi mixer.

8. The high-efficiency degreasing device for powder metallurgy injection molding blanks according to claim 1 is characterized in that: A manhole (211) is installed on the top of the nitric acid storage tank (2).

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