阅读说明：本技术 一种微推进剂药柱浇注系统及方法 (Micro-propellant grain pouring system and method ) 是由 胡松启 刘雪莉 刘林林 于 2021-06-09 设计创作，主要内容包括：本发明一种微推进剂药柱浇注系统及方法,属于航天推进技术领域；包括加压装置、恒温水浴循环装置、真空装置和浇注装置；恒温水浴循环装置设置于浇注装置的外围,通过设定温度的循环水维持浇注装置的内环境温度；加压装置通过加压管与转接盖连接,转接盖密封安装于恒温水浴循环装置和浇注装置的上端口,通过对浇注装置内加压,使得推进剂药浆从浇注口均匀留出；真空装置通过真空管与浇注装置底部连通,为推进剂药浆在下落过程提供负压环境,消除药浆中的气泡。通过高压气瓶对内衬内加压更易于高粘度药浆流出,使得该药柱浇注系统适用于高粘度药浆；能够通关控制高压气瓶的流量,对压力进行精密控制,进而对药柱浇注过程的流动速度控制更精准。(The invention relates to a micro-propellant grain pouring system and a method, belonging to the technical field of aerospace propulsion; comprises a pressurizing device, a constant-temperature water bath circulating device, a vacuum device and a pouring device; the constant-temperature water bath circulating device is arranged at the periphery of the pouring device and maintains the internal environment temperature of the pouring device through circulating water with set temperature; the pressurizing device is connected with the adapter cover through a pressurizing pipe, the adapter cover is hermetically arranged at the upper ports of the constant-temperature water bath circulating device and the pouring device, and propellant slurry is uniformly reserved from the pouring port by pressurizing the inside of the pouring device; the vacuum device is communicated with the bottom of the pouring device through a vacuum tube, so that a negative pressure environment is provided for the propellant slurry in the falling process, and bubbles in the slurry are eliminated. The high-viscosity slurry can flow out easily by pressurizing the inner lining through the high-pressure gas cylinder, so that the column pouring system is suitable for the high-viscosity slurry; can close the flow of control high pressure gas cylinder, carry out accurate control to pressure, and then more accurate to the flow velocity control of explosive column pouring process.)

1. A micro-propellant grain pouring system is characterized in that: comprises a pressurizing device, a constant-temperature water bath circulating device, a vacuum device and a pouring device; the constant-temperature water bath circulating device is arranged at the periphery of the pouring device, and the internal environment temperature of the pouring device is maintained through circulating water with set temperature;

the pressurizing device is connected with the adapter cover through a pressurizing pipe, the adapter cover is hermetically arranged at the upper ports of the constant-temperature water bath circulating device and the pouring device, and propellant slurry is uniformly reserved from the pouring port by pressurizing the inside of the pouring device;

the vacuum device is communicated with the bottom of the pouring device through a vacuum tube, so that a negative pressure environment is provided for the propellant slurry in the falling process, and bubbles in the slurry are eliminated.

2. The micro-propellant grain gating system of claim 1, wherein: the pressurizing device is a high-pressure gas cylinder, and a pressure reducing valve is arranged between an outlet of the pressurizing device and a switching cover of the pouring device; the high-pressure gas cylinder is filled with nitrogen.

3. The micro-propellant grain gating system of claim 1, wherein: the constant-temperature water bath circulating device comprises a water bath cavity, a constant-temperature water bath circulating pump, a water inlet pipe and a water return pipe, wherein the water outlet of the constant-temperature water bath circulating pump is connected with the water inlet of the water bath cavity through the water inlet pipe, and the water return port of the constant-temperature water bath circulating pump is connected with the water outlet of the water bath cavity through the water return pipe.

4. The micro-propellant grain gating system of claim 1, wherein: the constant-temperature water bath circulating device is of a double-layer wall structure, a water bath cavity is formed between the inner wall surface and the outer wall surface of the constant-temperature water bath circulating device, and the inner wall surface, the switching cover positioned at the top end and the bottom plate positioned at the bottom end form a pouring device with a sealed structure; the switching cover is installed in a matching mode with the internal thread at the upper end of the water bath cavity through threads.

5. The micro-propellant grain gating system of claim 1, wherein: two transparent observation windows are symmetrically arranged on the side wall of the water bath cavity along the front wall and the rear wall, so that the flowing condition of the slurry during pouring can be observed conveniently, and the pouring process can be controlled.

6. The micro-propellant grain gating system of claim 1, wherein: the upper part of the pouring device is provided with a lining for preventing propellant slurry from corroding the inner wall of the pouring device, and the material of the lining is brass; the liner is a sleeve with a convergent hole at the lower end, the upper end of the liner is tightly pressed and installed in a water bath cavity in a threaded fit mode through a switching cover, the lower end of the liner is an inverted cone-shaped convergent nozzle, a mold is correspondingly arranged right below the convergent nozzle, and the slurry is made into a thin strip shape and falls into the mold after passing through the convergent nozzle.

7. The micro-propellant grain gating system of claim 1, wherein: the bottom plate of the pouring device is of a cavity structure, 12 holes communicated with the cavity are uniformly distributed on the upper surface of the bottom plate along the circumference, a concave platform is arranged at the center of the bottom plate and used for placing a mold, 4 flange through holes are locally formed in the bottom surface of the bottom plate along the circumference, the bottom plate is connected with the bottom of the pouring device through 4 screws, the bottom plate and the pouring device are sealed through a sealing ring, and a hole is formed in the center of the bottom surface of the bottom plate and communicated with the cavity of the bottom plate; 4 supporting legs are uniformly distributed along the circumference below the pouring device and are used for supporting the pouring device.

8. The micro-propellant grain gating system of claim 1, wherein: the water outlet of the water bath cavity is positioned on the side wall of the upper end, and the water inlet of the water bath cavity is positioned on the side wall of the lower end.

9. The micro-propellant grain gating system of claim 1, wherein: the vacuum device comprises a vacuum pump, a vacuum pipe, a vacuum valve and an exhaust valve, the vacuum pump is communicated with the bottom plate of the pouring device through the vacuum pipe, the vacuum valve and the three-way pipe, and the exhaust valve is installed at a third connector of the three-way pipe.

10. A method for pouring micro propellant grains in the micro propellant grain pouring system of claim 1 comprises the following steps:

the method comprises the following steps: placing the mold on a bottom plate, connecting the bottom plate with a pouring device through screws, and sealing the bottom plate with the pouring device by adopting an O-shaped ring;

step two: the water outlet of the pouring device is connected with the water return port of the constant-temperature water bath circulating pump through the water return pipe, and the water inlet of the pouring device is connected with the water outlet of the constant-temperature water bath circulating pump through the water inlet pipe; the vacuum pump is communicated with the bottom plate through a vacuum pipe and a vacuum valve three-way pipe in sequence;

step three: opening a constant-temperature water bath circulating device, setting the water bath temperature according to the melting temperature of the medicine slurry, and preheating for 1 hour;

step four: transferring the slurry into the lining, placing the lining in a pouring device, connecting the adapter cover with the pouring device through threads, connecting the pressurizing pipe with the adapter cover, closing the exhaust valve and opening the vacuum valve;

step five: opening a vacuum pump to vacuumize a pouring chamber at the lower half part of a water bath cavity, observing the falling of the slurry through a transparent observation window, opening a gas cylinder if the slurry cannot normally flow through a liner contraction section due to too high viscosity, and applying certain pressure to the slurry through adjusting a pressure reducing valve to enable the slurry to smoothly fall;

step six: when the mold is observed to be filled with the slurry, closing the gas cylinder and the vacuum valve, and then closing the vacuum pump and slowly opening the exhaust valve;

step seven: and (3) disassembling the bottom plate and the pouring device, taking out the mold, placing the mold in an oven for a period of time, and demolding after the propellant is cured to obtain the formed micro-propellant grain.

Technical Field

The invention belongs to the technical field of aerospace propulsion, and particularly relates to a micro-propellant grain pouring system and a micro-propellant grain pouring method.

Background

At present, a micro power system with a low thrust characteristic has a wide application prospect in the aspects of micro satellite attitude and orbit control and missile precise guidance, and becomes one of the hot spots of the research of researchers at home and abroad. The micro-propulsion system can be divided into chemical micro-propulsion, cold air micro-propulsion and electric micro-propulsion according to different energy conversion modes, wherein the solid chemical micro-propulsion system has a good application prospect due to the advantages of simple structure, small volume, high integration level, reliable operation, low cost and the like. The conventional solid propellant manufacturing process can be divided into three types, namely a die casting method, a pressing and stretching method and a casting method, and the pressing and stretching method and the casting method are widely used grain forming methods at home and abroad at present, wherein the pressing and stretching method is commonly used for manufacturing middle and small engine charges by using a double-base propellant, and the casting method is commonly used for manufacturing large charges with complex configuration by using a composite solid propellant.

The invention patent CN201010598635.8 discloses an extrusion type micro-grain forming device, which generates a certain pressure by screwing a push rod, thereby extruding propellant grain slurry on a die into a die hole for forming. Although the device can realize the preparation of the micro-propellant grain, the formed grain possibly contains more bubbles, and for propellant slurry with higher viscosity, the extrusion, friction, rotation stress and the like generated in the preparation process can cause the energetic components to generate slow thermal decomposition and even explode.

The Wangjian et al (Wangjian, research on ink jet rapid prototyping technology of chemical chips [ D ]. Nanjing university of physical Engineers, 2006.) of Nanjing university of physical Engineers combined with the photocuring prototyping process and ink jet three-dimensional printing prototyping technology, established a rapid prototyping experimental apparatus for preparing Ultraviolet (UV) ink jet from energetic materials, proved that the ink jet rapid prototyping technology can rapidly, accurately, safely, automatically and no waste of medicament to realize the charging of micro-miniature drug columns, screened out the technological parameters applicable to ink jet rapid prototyping chemical chips through experiments, and analyzed the influence factors of ink curing. However, the main molding material of the technology is light-cured resin with high curing speed, low viscosity and small swelling, which is not suitable for other types of bonding systems, and high-viscosity propellant slurry cannot be used for preparing micro-propellant grains by the technology. In addition, the forming device comprises a UV light source, a three-dimensional forming platform, a forming control system, a spray head and a spraying action machine, the structure and the process are complex, and the cost is high.

Disclosure of Invention

The technical problem to be solved is as follows:

aiming at the defect that safe and reliable forming of the micro propellant grain is difficult to realize by high-viscosity materials at home and abroad at present, the system can effectively remove bubbles in high-viscosity slurry, realizes free filling and wall-attached casting forming of the microminiature propellant grain, and is simple and safe in preparation process.

The technical scheme of the invention is as follows: a micro-propellant grain pouring system is characterized in that: comprises a pressurizing device, a constant-temperature water bath circulating device, a vacuum device and a pouring device; the constant-temperature water bath circulating device is arranged at the periphery of the pouring device, and the internal environment temperature of the pouring device is maintained through circulating water with set temperature;

the pressurizing device is connected with the adapter cover through a pressurizing pipe, the adapter cover is hermetically arranged at the upper ports of the constant-temperature water bath circulating device and the pouring device, and propellant slurry is uniformly reserved from the pouring port by pressurizing the inside of the pouring device;

the vacuum device is communicated with the bottom of the pouring device through a vacuum tube, so that a negative pressure environment is provided for the propellant slurry in the falling process, and bubbles in the slurry are eliminated.

The further technical scheme of the invention is as follows: the pressurizing device is a high-pressure gas cylinder, and a pressure reducing valve is arranged between an outlet of the pressurizing device and a switching cover of the pouring device; the high-pressure gas cylinder is filled with nitrogen.

The further technical scheme of the invention is as follows: the constant-temperature water bath circulating device comprises a water bath cavity, a constant-temperature water bath circulating pump, a water inlet pipe and a water return pipe, wherein the water outlet of the constant-temperature water bath circulating pump is connected with the water inlet of the water bath cavity through the water inlet pipe, and the water return port of the constant-temperature water bath circulating pump is connected with the water outlet of the water bath cavity through the water return pipe.

The further technical scheme of the invention is as follows: the constant-temperature water bath circulating device is of a double-layer wall structure, a water bath cavity is formed between the inner wall surface and the outer wall surface of the constant-temperature water bath circulating device, and the inner wall surface, the switching cover positioned at the top end and the bottom plate positioned at the bottom end form a pouring device with a sealed structure; the switching cover is installed in a matching mode with the internal thread at the upper end of the water bath cavity through threads.

The further technical scheme of the invention is as follows: two transparent observation windows are symmetrically arranged on the side wall of the water bath cavity along the front wall and the rear wall, so that the flowing condition of the slurry during pouring can be observed conveniently, and the pouring process can be controlled.

The further technical scheme of the invention is as follows: the upper part of the pouring device is provided with a lining for preventing propellant slurry from corroding the inner wall of the pouring device, and the material of the lining is brass; the liner is a sleeve with a convergent hole at the lower end, the upper end of the liner is tightly pressed and installed in a water bath cavity in a threaded fit mode through a switching cover, the lower end of the liner is an inverted cone-shaped convergent nozzle, a mold is correspondingly arranged right below the convergent nozzle, and the slurry is made into a thin strip shape and falls into the mold after passing through the convergent nozzle.

The further technical scheme of the invention is as follows: the bottom plate of the pouring device is of a cavity structure, 12 holes communicated with the cavity are uniformly distributed on the upper surface of the bottom plate along the circumference, a concave platform is arranged at the center of the bottom plate and used for placing a mold, 4 flange through holes are locally formed in the bottom surface of the bottom plate along the circumference, the bottom plate is connected with the bottom of the pouring device through 4 screws, the bottom plate and the pouring device are sealed through a sealing ring, and a hole is formed in the center of the bottom surface of the bottom plate and communicated with the cavity of the bottom plate; 4 supporting legs are uniformly distributed along the circumference below the pouring device and are used for supporting the pouring device.

The further technical scheme of the invention is as follows: the water outlet of the water bath cavity is positioned on the side wall of the upper end, and the water inlet of the water bath cavity is positioned on the side wall of the lower end.

The further technical scheme of the invention is as follows: the vacuum device comprises a vacuum pump, a vacuum pipe, a vacuum valve and an exhaust valve, the vacuum pump is communicated with the bottom plate of the pouring device through the vacuum pipe, the vacuum valve and the three-way pipe, and the exhaust valve is installed at a third connector of the three-way pipe.

A method for pouring micro propellant grain in a micro propellant grain pouring system comprises the following specific steps:

the method comprises the following steps: placing the mold on a bottom plate, connecting the bottom plate with a pouring device through screws, and sealing the bottom plate with the pouring device by adopting an O-shaped ring;

step two: the water outlet of the pouring device is connected with the water return port of the constant-temperature water bath circulating pump through the water return pipe, and the water inlet of the pouring device is connected with the water outlet of the constant-temperature water bath circulating pump through the water inlet pipe; the vacuum pump is communicated with the bottom plate through a vacuum pipe and a vacuum valve three-way pipe in sequence;

step three: opening a constant-temperature water bath circulating device, setting the water bath temperature according to the melting temperature of the medicine slurry, and preheating for 1 hour;

step four: transferring the slurry into the lining, placing the lining in a pouring device, connecting the adapter cover with the pouring device through threads, connecting the pressurizing pipe with the adapter cover, closing the exhaust valve and opening the vacuum valve;

step five: opening a vacuum pump to vacuumize a pouring chamber at the lower half part of a water bath cavity, observing the falling of the slurry through a transparent observation window, opening a gas cylinder if the slurry cannot normally flow through a liner contraction section due to too high viscosity, and applying certain pressure to the slurry through adjusting a pressure reducing valve to enable the slurry to smoothly fall;

step six: when the mold is observed to be filled with the slurry, closing the gas cylinder and the vacuum valve, and then closing the vacuum pump and slowly opening the exhaust valve;

step seven: and (3) disassembling the bottom plate and the pouring device, taking out the mold, placing the mold in an oven for a period of time, and demolding after the propellant is cured to obtain the formed micro-propellant grain.

Advantageous effects

The invention has the beneficial effects that:

(1) the high-viscosity slurry can flow out easily by pressurizing the inner lining through the high-pressure gas cylinder, so that the slurry column pouring system is suitable for low-viscosity slurry and high-viscosity slurry; compared with the prior art which only heats the pouring cavity, the flow of the high-pressure gas cylinder can be controlled in a closed manner, the pressure is precisely controlled, and the flowing speed of the explosive column pouring process is more precisely controlled;

(2) the liner with a convergence structure at the lower end is adopted, so that the slurry can flow out in a dripping mode or in a bundle mode under the action of high-pressure air, and the flow rate of the slurry is wide in adjustment range, so that the size range of the micro-propellant grain which can be poured by the system is large; the nozzle and the lining are integrally designed, so that the pouring work can be better finished under the condition that accessories are not required to be added, and the design and manufacturing cost is reduced.

(3) The micro-propellant grain pouring system is adopted, bubbles in the grain slurry extruded from the lining nozzle can be removed through the vacuum device, so that the grain slurry falling into the die has no bubbles, and the grain column prepared after curing has a complete structure.

Drawings

FIG. 1 is a schematic view of a micro-propellant grain delivery system of the present invention;

FIG. 2 is a front cross-sectional view of the micro-propellant grain casting apparatus of the present invention;

FIG. 3 is a right sectional view of the micro-propellant grain casting apparatus of the present invention;

FIG. 4 is a left side sectional view of the micro-propellant grain casting apparatus of the present invention;

FIG. 5 is a top view of the micro-propellant grain casting apparatus of the present invention;

FIG. 6 is a front cross-sectional view of the adaptor cap of the present invention;

FIG. 7 is a top view of the adaptor cap of the present invention;

FIG. 8 is a front cross-sectional view of the liner of the present invention;

FIG. 9 is a top view of the liner of the present invention;

FIG. 10 is a front cross-sectional view of the base plate of the present invention;

FIG. 11 is a top view of the base plate of the present invention;

fig. 12 is a bottom view of the base plate of the present invention.

Description of reference numerals: 1. the device comprises a constant-temperature water bath circulating pump, a water return pipe, a high-pressure gas cylinder, a pressure pipe, a switching cover, a lining, a pouring device, a transparent window glass, a vacuum pump, a vacuum pipe, a water bath cavity, a vacuum valve, an exhaust valve, a bottom plate, a die, a water inlet pipe, a pressure reducing valve and a three-way pipe, wherein the constant-temperature water bath circulating pump comprises 2 the water return pipe, 3 the high-pressure gas cylinder, 4 the pressure pipe, 5 the switching cover, 6 the lining, 7 the pouring device, 8 the transparent window glass, 9 the vacuum pump, 10 the vacuum pipe, 11 the water bath cavity, 12 the vacuum valve, 13 the exhaust valve, 14 the bottom plate, 15 the die, 16 the water inlet pipe, 17 the pressure reducing valve and 18 the three-way pipe.

Detailed Description

The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Referring to fig. 1, the micro-propellant grain pouring system designed by the invention comprises a pressurizing device, a constant-temperature water bath circulating device, a vacuum device and a pouring device 4. The pressurizing device can pressurize the propellant slurry in the filling chamber of the pouring device, so that the propellant slurry can pass through the fine holes in the lining; the constant-temperature water bath circulating device maintains the environmental temperature of the pouring device through circulating water at a certain temperature, so that the temperature of the propellant slurry is maintained at a set temperature, and the propellant slurry is ensured to have stable fluidity; the vacuum device can provide a negative pressure environment for the propellant slurry in the falling process, and bubbles in the slurry are eliminated; the pouring device can realize the pouring molding of propellant slurry.

The one end of forcing pipe is connected with relief pressure valve 17's exit end, the other end and the switching lid 5 of forcing pipe are connected, the entry end of relief pressure valve 17 passes through the screw thread and is connected with high-pressure gas cylinder, switching lid 5 passes through the screw thread and is connected with the up end in water bath chamber 11, inside lining 6 is placed in the step department in water bath chamber 11, the screw thread terminal surface of switching lid 5 extrudees with the step face in water bath chamber 11, the centre is the edge of inside lining 6, consequently, inside lining 6 and switching lid 5 compress tightly sealed, nitrogen gas in the high-pressure gas cylinder passes through relief pressure valve 17 and transfers to behind the use pressure through the forcing pipe and gets into switching lid 5, thereby get into inside lining 6 that is equipped with propellant medicine thick liquid, can exert pressure to the medicine thick liquid, the nozzle outflow along the inside lining of extrusion propellant medicine thick liquid. The water bath cavity 11 is heated by circulating water, so that the temperature of propellant slurry is raised and maintained at a set temperature, and the temperature of the circulating water is controlled by a constant-temperature water bath circulating device. Two transparent observation windows 8 are symmetrically arranged on the side wall of the water bath cavity 11 along the front wall and the rear wall, so that the flowing condition of the slurry during pouring can be conveniently observed, and the pouring process can be further controlled. 4 supporting legs are uniformly distributed on a bottom plate 14 of the pouring device along the circumference and used for supporting the pouring device.

The side of the water bath cavity 11 is provided with two branch pipes which are respectively positioned on the side of the upper end and the side of the lower end of the pouring device, wherein the upper end is a water outlet, the lower end is a water inlet, the water inlet and the water outlet are communicated with the circulating water bath cavity of the pouring device, the water outlet of the constant-temperature water bath circulating pump is connected with the water inlet of the pouring device through a water inlet pipe, the water return port of the circulating water bath pump is connected with the water outlet of the pouring device through a water return pipe, and the circulating water bath pump, the water inlet pipe, the water inlet, the water outlet and the water return pipe jointly form the constant-temperature water bath circulating device.

The lining 6 is a part for protecting the inner wall of the pouring device from being corroded by propellant slurry, and considering that the brass has good heat conductivity and antistatic property, the lining is made of brass, the outer wall surface of the lining is tightly matched with the inner cavity of the water bath, the heat conduction between the inner wall of the water bath cavity and the lining can be promoted, the lower end of the lining is a convergent nozzle, and the slurry falls into a die in a thin strip shape after passing through the nozzle. The bottom plate is a supporting part of the mold, the bottom plate is of a cavity structure, 12 holes communicated with the cavity are uniformly distributed in the upper surface along the circumference, a concave table is arranged in the center and used for placing the mold, 4 flange through holes are locally formed in the bottom surface along the circumference, the bottom plate is connected with the pouring device through 4 screws, the bottom plate is sealed with the pouring device through a sealing ring, and a hole is formed in the center of the bottom surface of the bottom plate and communicated with the cavity of the bottom plate.

The central hole of the bottom plate 14 is welded with one end of a three-way pipe, the other two ends of the three-way pipe are respectively connected with an exhaust valve and a vacuum pump valve, and the other end of the vacuum pump valve is connected with a vacuum pump through a vacuum pipe.

The micro-propellant grain pouring system in the embodiment of the invention comprises a constant-temperature water bath circulating pump 1, a backwater 2 pipe, a high-pressure gas cylinder 3, a pressure pipe 4, a switching cover 5, a lining 6, a pouring device 7, a transparent window glass 8, a vacuum pump 9, a vacuum pipe 10, a water bath cavity 11, a vacuum valve 12, an exhaust valve 12, a bottom plate 14, a mold 15, a water inlet pipe 16, a pressure reducing valve 17 and a three-way pipe 18.

Referring to fig. 6 and 7, the upper end and the lower end of the adapter cap 5 are both external threads, wherein the external threads at the upper end are connected with one end of the pressurizing pipe 4, and the external threads at the lower end are connected with the upper end of the pouring device 7 and sealed by an O-shaped sealing ring; the center of the adapter cover 5 is a through hole which is respectively communicated with the pressurizing pipe 4 and the lining 6.

The other end of the pressure pipe 4 is connected with the outlet end of the pressure reducing valve 17 through pipe threads, and the inlet end of the pressure reducing valve 17 is connected with the opening of the high-pressure gas bottle 3 through pipe threads.

Referring to fig. 8 and 9, the lining 6 is in a circular tube shape, the upper end of the lining is in a step shape, the middle of the lining is a circular tube, the lower end of the lining is in a conical funnel shape, the outlet of the lining is a nozzle, the inner diameter of the nozzle is 2mm, the lining 6 is in clearance fit with the pouring device 7, and the step at the upper end of the lining 6 is used for supporting the lining 6 and positioning the lining.

Referring to fig. 2-5, pouring device 7 is the intermediate layer cavity structure, and the intermediate layer is water bath chamber 11, and there are two branches at pouring device 7's lateral wall face, is located upside and downside respectively, and the upside branch pipe is the delivery port branch pipe, and the downside branch pipe is the water inlet branch pipe, and the delivery port branch pipe is connected with the one end of wet return 2, and the water inlet branch pipe is connected with the one end of inlet tube 16, and the other end and the return water mouth of constant temperature water bath circulating pump 1 of wet return 2 are connected, and the other end and the delivery port of constant temperature water bath circulating pump 1 of inlet tube 16 are connected, install transparent window glass 8 on pouring device's the lateral wall for observe the pouring process of medicine thick liquid.

Referring to fig. 10-12, the bottom plate 14 is a cavity structure, 12 holes are uniformly distributed on the upper end surface along the circumference to be connected with the cavity, a groove is formed in the middle of the upper end surface, a mold 15 is placed on the groove, a hole with the diameter of 8mm is formed in the lower end surface of the bottom plate 14 and is communicated with the cavity, the hole in the lower end surface of the bottom plate 14 is connected with one end of a three-way pipe 18, and a flange of the bottom plate 14 is connected with the pouring device 7 through four screws and sealed by an O-shaped sealing ring.

The left end of the three-way pipe 18 is connected with the exhaust valve 13, the right end is connected with one end of the vacuum valve 12, the other end of the vacuum valve 12 is connected with one end of the vacuum pipe 10, and the other end of the vacuum pipe is connected with the vacuum pump 9.

The micro-propellant grain pouring forming method using the system comprises the following steps:

(1) placing the mold on a base, connecting the base with a pouring device through screws, and sealing the base with the pouring device by using an O-shaped ring;

(2) the water outlet branch pipe of the pouring device is connected with a water return port of the constant-temperature water bath circulating pump through a water return pipe, the water inlet branch pipe of the pouring device is connected with the water outlet of the constant-temperature water bath circulating pump through a water inlet pipe, and the vacuum pump is connected with the vacuum valve through a vacuum pipe.

(3) Opening a constant-temperature water bath circulation, setting the water bath temperature according to the melting temperature of the slurry, and preheating for 1 hour;

(4) transferring the slurry into the lining, placing the lining in a pouring device, connecting the adapter cover with the pouring device through threads, connecting the pressurizing pipe with the adapter cover, closing the exhaust valve and opening the vacuum valve;

(5) opening a vacuum pump to vacuumize a pouring chamber at the lower half part of a water bath cavity, observing the falling of the slurry through a transparent observation window, opening a gas cylinder if the slurry cannot normally flow through a liner contraction section due to too high viscosity, and applying certain pressure to the slurry through adjusting a pressure reducing valve to enable the slurry to smoothly fall;

(6) when the mold is observed to be filled with the slurry, closing the gas cylinder and the vacuum valve, and then closing the vacuum pump and slowly opening the exhaust valve;

(7) and (3) disassembling the bottom plate and the pouring device, taking out the mold, placing the mold in an oven for a period of time, and demolding after the propellant is cured to obtain the formed micro-propellant grain.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.