A pre-foaming machine for lost foam casting and its working method

Abstract

The present invention relates to a pre-foaming machine for lost foam casting and a working method thereof, which comprises a housing, a feeding assembly, a heating assembly, a transmission pipeline and a crushing assembly. The structure is reasonably arranged, the overall volume is reduced, and the integrated work of material heating, foaming and discharge is realized. Through reasonable pipeline arrangement, the foamed material can be easily crushed and transported to the outside of the device through the pipeline, which reduces labor and improves work efficiency.

Description

Technical Field

[0001] The invention relates to a pre-foaming device, in particular to an integrated pre-foaming machine for lost foam casting capable of realizing rapid foaming and rapid discharge and a working method thereof. Background Art

[0002] The application field of lost foam molds is becoming wider and wider, and it is a new casting technology with great development prospects. Lost foam molds have many advantages, such as: (1) The size and shape of the lost foam mold castings are accurate, the reproduction is good, it has the characteristics of precision casting, and the surface finish of the castings is high. (2) The sand core and core making department are eliminated, and the casting defects and waste caused by core making and core setting are eradicated. (3) Dry sand molding without binder, moisture, and any additives is adopted, which eradicates various casting defects and waste caused by moisture, additives and binders. (4) The sand processing system is greatly simplified, the molding sand can be fully reused, and the molding sand preparation department and the waste sand main department are eliminated.

[0003] Pre-foaming is one of the essential key steps in lost foam casting. The quality of pre-foaming is directly related to the quality and precision of the outer surface of the casting. With the widespread attention paid to the application of lost foam technology, people have also paid more attention to pre-foaming process equipment. However, the existing pre-foaming equipment is usually large in size and has unreasonable structural settings, especially for the material processing process after heating, which is more complicated and requires more labor resources. Summary of the invention

[0004] The main purpose of the present invention is to provide a device with reasonable structure, small volume and capable of quickly discharging pre-foamed materials.

[0005] In order to achieve the above-mentioned object, the present invention provides a pre-foaming machine for lost foam casting, which particularly comprises a casing, a feeding component, a heating component, a conveying pipeline and a crushing component;

[0006] The casing has a top wall, and the top wall has a feeding port; the feeding assembly is arranged inside the casing and below the feeding port; the heating assembly is connected to the feeding assembly, and the heating assembly includes a heating chamber and a stirring member, and the stirring member is arranged in the heating chamber; the transmission pipeline has a first compressed air pipe, a second compressed air pipe and an air outlet pipe, the upstream ends of the first compressed air pipe and the second compressed air pipe are both connected to the compressed air pump, the downstream ends of the first compressed air pipe are connected to the heating chamber, and the upstream end of the air outlet pipe is connected to the heating chamber; the crushing assembly has a crushing chamber and a crushing member, the crushing member is arranged in the crushing chamber, the crushing chamber is connected to the downstream end of the air outlet pipe, the lower end of the crushing chamber has a discharge port, the discharge port is connected to the second compressed air pipe through the discharge pipe, and the second compressed air pipe is also connected to the discharge pipe.

[0007] The beneficial effects of the above scheme are: reasonable structural setting, reduced overall volume, and realization of integrated work of material heating, foaming and discharge. Through reasonable pipeline layout, the foamed material can be easily crushed and transported to the outside of the device by pipeline, reducing labor and improving work efficiency.

[0008] A preferred solution is that the conveying pipeline also includes a backblowing assembly, the backblowing assembly includes a connecting pipe, the connecting pipe has a first plug interface, a second plug interface and a third plug interface, the first plug interface is connected to the first discharge pipe, the second plug interface is connected to the second compressed air pipe, the third plug interface is connected to the second discharge pipe, and the insertion section of the second compressed air pipe in the second plug interface extends beyond the first plug interface.

[0009] A preferred solution is that the feeding assembly has a feed barrel, a three-way pipe, a buffer barrel, a receiving bucket and a feed pipe that are connected in sequence, and the downstream end of the feed pipe is connected to the heating chamber.

[0010] The beneficial effect of the above solution is that it is convenient to control the outflow of materials, especially the provision of a three-way pipe facilitates the change of the outflow direction of the materials.

[0011] A preferred solution is that the three-way pipe includes a first branch pipe, a second branch pipe and a third branch pipe, the first branch pipe is connected to the barrel outlet of the feed barrel, the second branch pipe is connected to the buffer barrel, the third branch pipe is connected to the return pipe, the end of the return pipe extends to the outside of the casing, the top wall has an outlet, and the discharge pipe extends from the outlet to the outside of the casing;

[0012] The second branch pipe is provided with a first valve, the third branch pipe is provided with a second valve, the first valve has a first cylinder and a first plug plate, the first plug plate is arranged on the second branch pipe, the second valve has a second cylinder and a second plug plate, the second plug plate is arranged on the third branch pipe.

[0013] A preferred solution is that a buffer valve is provided in the buffer barrel, the buffer valve has a third cylinder and a closing plate, and the closing plate has a weighing unit.

[0014] The beneficial effects of the above scheme are: automatic weighing of materials is achieved, eliminating the process of manual weighing before putting the materials in, further improving automation, and making it easier to use.

[0015] A preferred solution is that the stirring member has a stirring motor and a stirring rod connected in sequence, the stirring rod has an axis rod and a plate body, the plate body includes a plurality of vertical plates arranged perpendicular to the axis rod and a horizontal plate arranged parallel to the axis rod, and the horizontal plate is spaced apart from the inner wall surface of the heating chamber at a distance of less than 1 cm.

[0016] The beneficial effect of the above scheme is that the end of the horizontal plate is very close to the inner wall surface. According to practical experience, the ends of the stirring rods of the existing structure are far away from the inner wall surface, which makes it impossible to stir the foaming material on the inner wall surface well during the stirring process, which often causes the problem of uneven local stirring. However, since the horizontal plate of this scheme is very close to the inner wall surface, the uniformity of stirring is significantly improved, thereby ensuring the foaming effect.

[0017] A preferred solution is that the heating chamber comprises a multi-layer structure, wherein the multi-layer structure comprises a stainless steel layer, a heat-insulating layer, a heating film layer and an aluminum shell layer in sequence from the outside to the inside.

[0018] The structural setting is very reasonable. The aluminum shell layer can achieve very good heat conduction effect, while the thermal insulation layer can achieve very good thermal insulation effect.

[0019] A preferred solution is that the pre-foaming machine for lost foam casting also includes a video monitoring device, which includes a camera, a controller and a display screen connected in sequence, the camera is arranged in the heating chamber, and the display screen is arranged on the outer wall of the casing.

[0020] The working method of the pre-foaming machine for lost foam casting provided by the present invention comprises the following steps:

[0021] S1: Add the material to be foamed into the feeding port, and the material moves into the feeding assembly;

[0022] S2: the material enters the heating component, specifically the heating chamber, from the feeding component;

[0023] S3: starting the heating operation so that the temperature in the heating chamber rises to a required temperature;

[0024] S4: stirring and turning the material in the heating chamber by a stirring member, and performing a foaming process at the same time;

[0025] S5: Stop the foaming process, start the compressed air pump, so that the first compressed air pipe supplies positive pressure airflow to the heating chamber, and the material in the heating chamber moves downstream along the air outlet pipe driven by the positive pressure airflow;

[0026] S6: the material is transferred along the air outlet pipe to the crushing chamber of the crushing assembly, and the crushing element performs a crushing operation on the material in the crushing chamber;

[0027] S7: The crushed material enters the second compressed air pipe along the discharge pipe, and the compressed air pump provides positive pressure to the second compressed air pipe, so that the second compressed air pipe drives the crushed material to be discharged.

[0028] A preferred solution is,

[0029] The feeding assembly comprises a feed barrel, a tee pipe, a buffer barrel, a receiving bucket and a feed pipe which are connected in sequence, and the downstream end of the feed pipe is connected to the heating chamber; the tee pipe comprises a first branch pipe, a second branch pipe and a third branch pipe, the first branch pipe is connected to the barrel outlet of the feed barrel, the second branch pipe is connected to the buffer barrel, the third branch pipe is connected to a return pipe, the end of the return pipe extends to the outside of the casing, the top wall has an outlet, and the discharge pipe extends from the outlet to the outside of the casing;

[0030] The second branch pipe is provided with a first valve, the third branch pipe is provided with a second valve, the first valve has a first cylinder and a first plug plate, the first plug plate is arranged on the second branch pipe, the second valve has a second cylinder and a second plug plate, the second plug plate is arranged on the third branch pipe; the buffer barrel is provided with a buffer valve, the buffer valve has a third cylinder and a closing plate, and the closing plate has a weighing unit;

[0031] The working method comprises the following steps:

[0032] Y1: The material enters the feed barrel and then enters the three-way pipe;

[0033] Y2: Open the first valve of the second branch pipe, that is, control the first plug plate through the first cylinder to make the second branch pipe open, so that the material enters the buffer barrel;

[0034] Y3: Weighing the buffer barrel by a weighing unit, and then opening the buffer valve, that is, controlling the closing plate by a third cylinder to open the passage of the buffer barrel, so that the material enters the receiving bucket;

[0035] Y4: the material then enters the heating chamber from the receiving bucket;

[0036] Y5: When there is no need to add materials into the buffer barrel, the second valve is opened, that is, the second plug plate is controlled by the second cylinder to open the third branch pipe, so that the material in the feed barrel is discharged from the return pipe and recycled.

[0037] A preferred solution is that the heating chamber comprises a multi-layer structure, wherein the multi-layer structure has a stainless steel layer, a heat-insulating layer, a heating film layer and an aluminum shell layer in sequence from the outside to the inside; the pre-foaming machine for lost foam casting also includes a video monitoring device, which includes a camera, a controller and a display screen connected in sequence, the camera is arranged in the heating chamber, and the display screen is arranged on the outer wall of the casing;

[0038] The working method comprises the following steps: providing heat through a heating film layer, the heat quickly heats the internal material along the aluminum shell layer, and the heat is kept warm through the insulation layer, and a stable structure is provided and easy to fix through the stainless steel layer; in addition, the internal environment of the heating chamber is photographed by a camera, and the working environment in the heating chamber is displayed on a display screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0040] Figure 1 It is a structural schematic diagram of a pre-foaming machine for lost foam casting of the present invention;

[0041] Figure 2 It is a schematic structural diagram of a pre-foaming machine for lost foam casting of the present invention (part of the housing is omitted);

[0042] Figure 3 It is a structural schematic diagram of another viewing angle of the pre-foaming machine for lost foam casting of the present invention (with part of the housing omitted);

[0043] Figure 4 It is a structural schematic diagram of a feeding assembly of a pre-foaming machine for lost foam casting of the present invention;

[0044] Figure 5 It is a structural schematic diagram of a feeding assembly of a pre-foaming machine for lost foam casting of the present invention;

[0045] Figure 6 It is a structural schematic diagram of a stirring structure of a pre-foaming machine for lost foam casting of the present invention;

[0046] Figure 7 It is a structural schematic diagram of a cross-sectional state of a heating chamber of a pre-foaming machine for lost foam casting of the present invention;

[0047] Figure 8 It is a schematic diagram of a pre-foaming machine for lost foam casting of the present invention;

[0048] Fig. 9 The present invention is a schematic structural diagram of a back-blowing assembly of a pre-foaming machine for lost foam casting. DETAILED DESCRIPTION

[0049] The technical scheme in the embodiment of the present invention is described clearly and completely below in conjunction with the accompanying drawings in the embodiment of the present invention. In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0050] First embodiment:

[0051] like Figures 1 to 3 As shown, the present invention provides a pre-foaming machine for lost foam casting, which includes a casing 1, a feeding component 10, a heating component 20, a conveying pipe 30 and a crushing component 40.

[0052] The housing 1 has a top wall 2, and the top wall 2 has a feeding port 3 and an outlet 6; the feeding assembly 10 is arranged inside the housing 1 and below the feeding port 3. The heating assembly 20 is connected to the feeding assembly 10, and the heating assembly 20 includes a heating chamber 21 and a stirring member 22, and the stirring member 22 is arranged in the heating chamber 21; the transmission pipeline 30 has a first compressed air pipe 31, a second compressed air pipe 32 and an air outlet pipe 33, and the upstream ends of the first compressed air pipe 31 and the second compressed air pipe 32 are both connected to a compressed air pump 34, and the compressed air pump 34 can be two independent pumps. The downstream end of the first compressed air pipe 31 is connected to the heating chamber 21, and the upstream end of the air outlet pipe 33 is connected to the heating chamber 21; the crushing assembly 40 has a crushing chamber 41 and a crushing piece 42, and the crushing piece 42 is preferably a stirring rod structure or an impact block structure for crushing the material. The crushing piece 42 is arranged in the crushing chamber 41, and the crushing chamber 41 is connected to the downstream end of the air outlet pipe 33. The lower end of the crushing chamber 41 has a discharge port 43, and the discharge port 43 is connected to the second compressed air pipe 32 through a first discharge pipe 44, and the second compressed air pipe 32 is also connected to a second discharge pipe 45.

[0053] The working method of the pre-foaming machine for lost foam casting provided by the present invention comprises the following steps:

[0054] S1: Add the material to be pre-foamed into the feeding port 3, and the material moves into the feeding assembly 10;

[0055] S2: The material enters the heating assembly 20 from the feeding assembly 10, specifically, enters the heating chamber 21;

[0056] S3: Start the heating operation so that the temperature in the heating chamber 21 rises to the required temperature;

[0057] S4: The material in the heating chamber 21 is stirred and turned by the stirring member 22, and a pre-foaming process is performed at the same time;

[0058] S5: Stop the pre-foaming process, start the compressed air pump 34, so that the first compressed air pipe 31 supplies positive pressure airflow into the heating chamber 21, and the material in the heating chamber 21 moves downstream along the air outlet pipe 33 driven by the positive pressure airflow;

[0059] S6: The material is transferred along the air outlet pipe 33 to the crushing chamber 41 of the crushing assembly 40, and the crushing member 42 performs a crushing operation on the material in the crushing chamber 41; the purpose of the crushing operation is to crush and reduce a part of the material that has formed adhesion or agglomeration, which is beneficial to the subsequent foaming process.

[0060] S7: The crushed material enters the second compressed air pipe 32 along the first discharge pipe 44, and another compressed air pump 34 provides positive pressure to the second compressed air pipe 32, so that the second compressed air pipe 32 drives the crushed material to be discharged from the outlet 6 of the top wall 2 along the second discharge pipe 45. Another process after pre-foaming is the foaming process, which is usually completed by the corresponding foaming mold.

[0061] Second embodiment:

[0062] like Figure 8 and Fig. 9 As shown, the conveying pipeline also includes a backblowing assembly 50, which includes a connecting pipe 54. The connecting pipe 54 has a first plug interface 51, a second plug interface 52 and a third plug interface 53. The first plug interface 51 is connected to the first discharge pipe 44, the second plug interface 52 is connected to the second compressed air pipe 32, the third plug interface 53 is connected to the second discharge pipe 45, and the insertion section 55 of the second compressed air pipe 32 in the second plug interface 52 extends beyond the first plug interface 51.

[0063] The working method of the pre-foaming machine for lost foam casting of the present embodiment is as follows:

[0064] In S7: the crushed material enters the connecting pipe 54 from the position of the first plug port 51 along the first discharge pipe 44, and at the same time, the second compressed air pipe 32 supplies airflow to the connecting pipe 54, so that the material in the connecting pipe 54 enters the second discharge pipe 45 along the third plug port 53 and finally rises to the position of the top outlet 6. In addition, since the insertion section of the second compressed air pipe 32 in the second plug port 52 extends beyond the first plug port 51, when the airflow is supplied to the connecting pipe 54 through the second compressed air pipe 32, no back-blowing phenomenon occurs, that is, the material will not be blown back to the direction of the first discharge pipe 44.

[0065] Third embodiment:

[0066] like Figure 4 and Figure 5 As shown, the feeding assembly 10 has a feed barrel 9, a tee pipe 11, a buffer barrel 12, a receiving bucket 13 and a feed pipe 14 connected in sequence, and the downstream end of the feed pipe 14 is connected to the heating chamber 21; the tee pipe 11 includes a first branch pipe 15, a second branch pipe 16 and a third branch pipe 17, the first branch pipe 15 is connected to the barrel outlet 8 of the feed barrel 9, the second branch pipe 16 is connected to the buffer barrel 12, and the third branch pipe 17 is connected to the return pipe 18, and the end of the return pipe 18 extends to the outside of the housing 1. The top wall 2 has an outlet 6, and the second discharge pipe 45 extends from the outlet 6 to the outside of the housing 1;

[0067] The second branch pipe 16 is provided with a first valve, the third branch pipe 17 is provided with a second valve, the first valve has a first cylinder 161 and a first plug plate, the first plug plate is arranged on the second branch pipe 16, the second valve has a second cylinder 171 and a second plug plate, the second plug plate is arranged on the third branch pipe 17; the buffer barrel 12 is provided with a buffer valve, the buffer valve has a third cylinder and a closing plate, and the closing plate 122 has a weighing unit;

[0068] The working method comprises the following steps:

[0069] Y1: The material enters the feed barrel 9 and then enters the three-way pipe 11;

[0070] Y2: Open the first valve of the second branch pipe 16, that is, control the first plug plate through the first cylinder 161 to make the second branch pipe 16 open, so that the material enters the buffer barrel 12;

[0071] Y3: Weigh the material in the buffer barrel 12 through the weighing unit, and then open the buffer valve, that is, control the closing plate through the third cylinder to open the passage of the buffer barrel 12, so that the material enters the receiving bucket 13;

[0072] Y4: The material then enters the heating chamber 21 from the receiving bucket 13;

[0073] Y5: When it is not necessary to add materials into the buffer barrel 12, the second valve is opened, that is, the second plug plate is controlled by the second cylinder 171 to open the third branch pipe 17, so that the materials in the feed barrel 9 are discharged from the return pipe 18 and recycled.

[0074] Fourth embodiment:

[0075] like Figure 6 and Figure 7 As shown, as a preferred embodiment, the stirring member 22 of this embodiment has a stirring motor 221 and a stirring rod connected in sequence, the stirring rod has a shaft 222 and a plate body, the plate body includes a plurality of vertical plates 223 arranged perpendicular to the shaft 222 and a horizontal plate 224 arranged parallel to the shaft 222, and the horizontal plate 224 is spaced apart from the inner wall surface of the heating chamber 21 by less than 1 cm.

[0076] The heating chamber 21 includes a multilayer structure 25, wherein the multilayer structure 25 has a stainless steel layer 26, a heat preservation layer 27, a heating film layer 28 and an aluminum shell layer 29 in sequence from the outside to the inside; the pre-foaming machine for lost foam casting also includes a video monitoring device, which includes a camera, a controller and a display screen 24 connected in sequence, the camera is arranged in the heating chamber 21, and the display screen 24 is arranged on the outer wall 4 of the casing 1. The heating film layer 28 is preferably a resistance wire structure, which is electrically heated by power supply. The heat preservation layer 27 adopts the heat preservation structure in the prior art, such as an asbestos heat preservation layer.

[0077] The working method includes the following steps: heat is provided by the heating film layer 28, the heat is quickly heated along the aluminum shell layer 29 to heat the internal material, and the heat is kept warm by the insulation layer 27, and a stable structure is provided and easy to fix by the stainless steel layer 26; in addition, the internal environment of the heating chamber 21 is photographed by a camera, and the working environment in the heating chamber 21 is displayed by the display screen 24.

[0078] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A pre-foaming machine for lost foam casting, characterized in that: include: The casing has a top wall, and the top wall has a feeding port; A feeding assembly is arranged inside the housing and below the feeding port; A heating assembly, the heating assembly is connected to the feeding assembly, the heating assembly comprises a heating chamber and a stirring member, the stirring member is arranged in the heating chamber; the heating chamber comprises a multi-layer structure; A transmission pipeline, comprising a first compressed air pipe, a second compressed air pipe and an air outlet pipe, wherein the upstream ends of the first compressed air pipe and the second compressed air pipe are both connected to a compressed air pump, the downstream end of the first compressed air pipe is connected to the heating chamber, and the upstream end of the air outlet pipe is connected to the heating chamber; A crushing assembly, wherein the crushing assembly comprises a crushing chamber and a crushing member, wherein the crushing member is arranged in the crushing chamber, wherein the crushing chamber is connected to the downstream end of the air outlet pipe, wherein the lower end of the crushing chamber comprises a discharge port, wherein the discharge port is connected to the second compressed air pipe through a first discharge pipe, and the second compressed air pipe is also connected to the second discharge pipe; The pre-foaming machine for lost foam casting also includes a video monitoring device.

2. The pre-foaming machine for lost foam casting according to claim 1, characterized in that: The conveying pipeline also includes a backblowing assembly, which includes a connecting pipe, and the connecting pipe has a first plug interface, a second plug interface and a third plug interface, the first plug interface is connected to the first discharge pipe, the second plug interface is connected to the second compressed air pipe, the third plug interface is connected to the second discharge pipe, and the insertion section of the second compressed air pipe in the second plug interface extends beyond the first plug interface.

3. The pre-foaming machine for lost foam casting according to claim 1, characterized in that: The feeding assembly comprises a feed barrel, a three-way pipe, a buffer barrel, a receiving bucket and a feed pipe which are connected in sequence, and the downstream end of the feed pipe is connected to the heating chamber.

4. The pre-foaming machine for lost foam casting according to claim 3, characterized in that: The three-way pipe includes a first branch pipe, a second branch pipe and a third branch pipe, the first branch pipe is connected to the barrel outlet of the feed barrel, the second branch pipe is connected to the buffer barrel, the third branch pipe is connected to the return pipe, the end of the return pipe extends to the outside of the casing, the top wall has an outlet, and the second discharge pipe extends from the outlet to the outside of the casing; The second branch pipe is provided with a first valve, the third branch pipe is provided with a second valve, the first valve has a first cylinder and a first plug plate, the first plug plate is arranged on the second branch pipe, the second valve has a second cylinder and a second plug plate, the second plug plate is arranged on the third branch pipe.

5. The pre-foaming machine for lost foam casting according to claim 4, characterized in that: A buffer valve is provided in the buffer barrel, the buffer valve has a third cylinder and a closing plate, and the closing plate has a weighing unit; The stirring member has a stirring motor and a stirring rod connected in sequence, the stirring rod has an axis rod and a plate body, the plate body includes a plurality of vertical plates arranged perpendicular to the axis rod and a horizontal plate arranged parallel to the axis rod, and the horizontal plate is spaced apart from the inner wall surface of the heating chamber by less than 1 cm.

6. The pre-foaming machine for lost foam casting according to claim 1, characterized in that: The multi-layer structure comprises a stainless steel layer, a heat-insulating layer, a heating film layer and an aluminum shell layer in sequence from the outside to the inside.

7. The pre-foaming machine for lost foam casting according to claim 1, characterized in that: The video monitoring device comprises a camera, a controller and a display screen which are connected in sequence. The camera is arranged in the heating chamber, and the display screen is arranged on the outer wall of the casing.

8. The working method of the pre-foaming machine for lost foam casting according to claim 1, characterized in that: The following steps are included: S1: Add the material to be foamed into the feeding port, and the material moves into the feeding assembly; S2: the material enters the heating component, specifically the heating chamber, from the feeding component; S3: starting the heating operation so that the temperature in the heating chamber rises to a required temperature; S4: stirring and turning the material in the heating chamber by a stirring member, and performing a foaming process at the same time; S5: Stop the foaming process, start the compressed air pump, so that the first compressed air pipe supplies positive pressure airflow to the heating chamber, and the material in the heating chamber moves downstream along the air outlet pipe driven by the positive pressure airflow; S6: the material is transferred along the air outlet pipe to the crushing chamber of the crushing assembly, and the crushing element performs a crushing operation on the material in the crushing chamber; S7: The crushed material enters the second compressed air pipe along the first discharge pipe, and the compressed air pump provides positive pressure to the second compressed air pipe, so that the second compressed air pipe drives the crushed material to be discharged.

9. The working method of the pre-foaming machine for lost foam casting according to claim 8, characterized in that: The feeding assembly comprises a feed barrel, a tee pipe, a buffer barrel, a receiving bucket and a feed pipe which are connected in sequence, and the downstream end of the feed pipe is connected to the heating chamber; the tee pipe comprises a first branch pipe, a second branch pipe and a third branch pipe, the first branch pipe is connected to the barrel outlet of the feed barrel, the second branch pipe is connected to the buffer barrel, the third branch pipe is connected to a return pipe, the end of the return pipe extends to the outside of the casing, the top wall has an outlet, and the second discharge pipe extends from the outlet to the outside of the casing; The second branch pipe is provided with a first valve, the third branch pipe is provided with a second valve, the first valve has a first cylinder and a first plug plate, the first plug plate is arranged on the second branch pipe, the second valve has a second cylinder and a second plug plate, the second plug plate is arranged on the third branch pipe; the buffer barrel is provided with a buffer valve, the buffer valve has a third cylinder and a closing plate, and the closing plate has a weighing unit; The working method comprises the following steps: Y1: The material enters the feed barrel and then enters the three-way pipe; Y2: Open the first valve of the second branch pipe, that is, control the first plug plate through the first cylinder to make the second branch pipe open, so that the material enters the buffer barrel; Y3: Weighing the buffer barrel by a weighing unit, and then opening the buffer valve, that is, controlling the closing plate by a third cylinder to open the passage of the buffer barrel, so that the material enters the receiving bucket; Y4: the material then enters the heating chamber from the receiving bucket; Y5: When there is no need to add materials into the buffer barrel, the second valve is opened, that is, the second plug plate is controlled by the second cylinder to open the third branch pipe, so that the material in the feed barrel is discharged from the return pipe and recycled.

10. The working method of the pre-foaming machine for lost foam casting according to claim 8 or 9, characterized in that: The stirring member comprises a stirring motor and a stirring rod connected in sequence, the stirring rod comprises a shaft and a plate body, the plate body comprises a plurality of vertical plates arranged perpendicular to the shaft and a horizontal plate arranged parallel to the shaft, and the horizontal plate is spaced apart from the inner wall surface of the heating chamber by less than 1 cm; The multi-layer structure comprises a stainless steel layer, a heat-insulating layer, a heating film layer and an aluminum shell layer in sequence from the outside to the inside; the video monitoring device comprises a camera, a controller and a display screen connected in sequence, the camera is arranged in the heating chamber, and the display screen is arranged on the outer wall of the housing; The working method comprises the following steps: providing heat through a heating film layer, the heat quickly heats the internal material along the aluminum shell layer, and the heat is kept warm through the insulation layer, and a stable structure is provided and easy to fix through the stainless steel layer; in addition, the internal environment of the heating chamber is photographed by a camera, and the working environment in the heating chamber is displayed on a display screen.

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