A negative pressure feeder for quantitative suction of material by a material loading machine

Abstract

The utility model provides a kind of negative pressure feeder for the quantitative suction of feeding machine, it includes: bunker, feeding device, suction device, feeding device includes feeding screw, feeding power mechanism, feeding screw is installed at bunker bottom, feeding power mechanism is located outside bunker, and is connected with the one end of feeding screw and drives feeding screw, and the other end of feeding screw exports from the discharge port of bunker, suction device includes suction pipe, pipe cleaning valve, air supplement valve, suction pipe is horizontally arranged, and suction pipe is communicated with discharge port, two valves are all arranged in the top of suction pipe, and first air inlet, which is communicated with pipe cleaning valve, and second air inlet, which is communicated with air supplement valve, are arranged on suction pipe, pipe cleaning valve controls the switch of first air inlet, and air supplement valve controls the size and switch of the air intake of second air inlet.The utility model solves the problem that negative pressure feeder cannot accurately control the amount of material conveyed to feeding machine in prior art.

Description

Technical Field

[0001] This utility model relates to the field of material conveying technology, and in particular to a negative pressure feeder for quantitative material intake in a feeding machine. Background Technology

[0002] Vacuum metering feeders use a vacuum negative pressure conveying device to draw material from a negative pressure feeder. Vacuum negative pressure conveying devices generally have a high conveying speed, and the suction speed cannot be adjusted by controlling the fan airflow, which can easily cause pipe blockage. For precise control, it needs to be used in conjunction with a negative pressure feeder. The material is pushed out by a screw inside the negative pressure feeder and then transported through pipes to the vacuum metering feeder.

[0003] The processing capacity of vacuum metering feeders is typically 5-20 t / h. Summary of the Invention

[0004] The technical problem to be solved by this utility model embodiment is to provide a negative pressure feeder for quantitative material intake of a feeding machine, thereby solving the problem that the existing negative pressure feeder cannot accurately control the amount of material conveyed to the feeding machine.

[0005] To solve the above-mentioned technical problems, this utility model provides a negative pressure feeder for quantitative material suction in a feeding machine, comprising: A hopper is used to hold materials. The hopper has an inlet at the top and an outlet at the bottom. A feeding device is installed at the bottom of the hopper. The feeding device includes a feeding screw and a feeding power mechanism. The feeding screw is installed through the bottom of the hopper. The feeding power mechanism is located outside the hopper, connected to one end of the feeding screw and driving the feeding screw. The other end of the feeding screw outputs from the outlet of the hopper. The suction device is connected to the discharge port of the silo and includes a suction pipe, a cleaning valve, and an air replenishment valve. The suction pipe is arranged horizontally, and both valves are located at the top of the suction pipe. The suction pipe is connected to the discharge port. The suction pipe is provided with a first air inlet connected to the cleaning valve and a second air inlet connected to the air replenishment valve. The pigging valve controls the opening and closing of the first air inlet; The supplemental air valve controls the amount of air intake and its on / off state at the second air inlet; The feeding device is set to multiple sets, and correspondingly, the suction device is also set to multiple sets.

[0006] The pipeline cleaning valve includes a pipeline cleaning valve body, a pipeline cleaning plug, and a pipeline cleaning valve cylinder. The bottom opening of the pipeline cleaning valve body is connected to the first air inlet. Several ventilation holes are opened on the pipeline cleaning valve body. The pipeline cleaning valve cylinder is installed at the upper end of the pipeline cleaning valve body. The pipeline cleaning plug is placed in the pipeline cleaning valve body. The piston rod of the pipeline cleaning valve cylinder is connected to the pipeline cleaning plug and moves up and down to control the opening and closing of the first air inlet.

[0007] The air replenishment valve includes an air replenishment valve cavity, an air replenishment plug, an air replenishment valve cylinder, and an air regulating mechanism. The bottom opening of the air replenishment valve cavity is connected to the second air inlet. An air inlet is provided on the side of the air replenishment valve cavity. An air regulating mechanism for adjusting the air intake is installed at the air inlet of the air replenishment valve cavity. The air replenishment valve cylinder is installed at the upper end of the air replenishment valve cavity. The air replenishment plug is disposed in the air replenishment valve cavity. The piston rod of the air replenishment valve cylinder is connected to the air replenishment plug and moves up and down to control the opening and closing of the second air inlet.

[0008] The air regulating mechanism includes a first air regulating plate and a second air regulating plate. The first air regulating plate and the second air regulating plate have the same shape. With the center of the first air regulating plate as the center, n fan-shaped areas with the same angle are set, where n is an even number. Multiple arc-shaped ventilation openings are opened in the fan-shaped areas. The radii of the arc-shaped ventilation openings of two adjacent fan-shaped areas are different, and the arc-shaped ventilation openings of two adjacent fan-shaped areas are staggered. The first air regulating plate is fixed at the air inlet of the air supply valve cavity, and the second air regulating plate rotates with the first air regulating plate on the same central axis.

[0009] It also includes a stirring device, which includes a stirring and dispersing device and a stirring power mechanism. The stirring and dispersing device is installed in the silo, and the stirring power mechanism is connected to the stirring and dispersing device to transmit power. The stirring and dispersing device includes a rotating shaft, multiple dispersing mechanisms, and two threaded push plates. The two threaded push plates are wound around the rotating shaft, and the threads of the two threaded push plates rotate in opposite directions. The dispersing mechanisms are fixed on the rotating shaft and are located on both sides of the threaded push plates. The mixing and dispersing device is located above the feeding screw, and the rotating shaft is perpendicular to the feeding screw.

[0010] The dispersing mechanism includes a dispersing plate and a dispersing rod. The dispersing plate is vertically fixed on the rotating shaft, and the dispersing rod is vertically fixed on the dispersing plate. The dispersing rod is parallel to the rotating shaft.

[0011] The diameter of the feed screw thread decreases from one end to the other, and the end with the smaller diameter feed screw thread is located in the suction tube, with space between the feed screw thread and the suction tube.

[0012] The feeding power mechanism includes a feeding motor and a feeding reducer. The feeding motor and the feeding reducer are connected for power transmission, and the feeding reducer is connected for power transmission to the feeding screw. The stirring power mechanism includes a stirring motor and a stirring reducer. The stirring motor and the stirring reducer are connected for power transmission, and the stirring reducer is connected to the rotating shaft for power transmission.

[0013] Multiple level gauges are installed on the side wall of the silo. The detection part of the level gauge is located in the silo and between two adjacent feeding screws. The height of the detection part of the level gauge is higher than the height of the feeding screw.

[0014] Two ventilation openings are provided at the top of the hopper.

[0015] This utility model provides a negative pressure feeder for quantitative material suction in a feeding machine, which can realize both rapid feeding and slow, precise feeding modes, and is suitable for various feeding production processes. In the slow, precise feeding mode, it can stably and accurately control the material conveying volume. The feeding device and the suction device form a set, which can realize material conveying for multiple pipelines and different production needs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the negative pressure feeder for quantitative material intake in a feeding machine according to this utility model.

[0017] Figure 2 This is a front view of the negative pressure feeder for quantitative material intake in a feeding machine according to this utility model.

[0018] Figure 3 for Figure 2 Sectional view at point AA.

[0019] Figure 4 for Figure 3 A magnified view of a section at point B.

[0020] Figure 5 This is a top view of the dismantled upper part of the hopper according to this utility model.

[0021] Figure 6 This is a schematic diagram of the structure of the stirring and dispersing device of this utility model.

[0022] Figure 7 This is a schematic diagram of the feeding screw of this utility model.

[0023] Figure 8 This is a schematic diagram of the air regulating mechanism of this utility model.

[0024] In the picture: 1. Hopper; 2. Feeding device; 3. Suction device; 4. Mixing device; 5. Level gauge; 6. Vent; 11. Inlet; 12. Outlet; 21. Feeding screw; 22. Feeding power mechanism; 31. Suction pipe; 32. Pipe cleaning valve; 33. Air replenishment valve; 34. First air inlet; 35. Second air inlet; 41. Mixing and dispersing device; 42. Mixing power mechanism; 221. Feeding motor; 222. Feeding reducer; 321. Pipe cleaning valve cavity; 322. Pipe cleaning block; 323. Pipe cleaning valve cylinder; 331. Air replenishment valve cavity; 332. Air replenishment block; 333. Air replenishment valve cylinder; 334. Air regulating mechanism; 411. Rotating shaft; 412. Dispersing mechanism; 413. Threaded push plate; 421. Mixing motor; 422. Mixing reducer; 3341. First air regulating plate; 3342. Second air regulating plate; 4121. Dispersing plate; 4122. Dispersing rod. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0026] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Example

[0028] This utility model provides a negative pressure feeder for quantitative material suction in a feeding machine, such as... Figure 1-8 It includes: a hopper 1, a feeding device 2, a suction device 3, and a mixing device 4. The hopper 1 is used to hold materials, and an inlet 11 is opened at the top of the hopper 1 for conveying materials into the hopper 1, such as... Figure 3 The lower end is provided with a discharge port 12, which is used to transport the material in the hopper 1 to the subsequent vacuum metering feeder.

[0029] The feeding device 2 is installed at the bottom of the hopper 1, such as... Figure 3 The feeding device 2 includes a feeding screw 21 and a feeding power mechanism 22. The feeding screw 21 is installed through the bottom of the hopper 1. The feeding power mechanism 22 is located outside the hopper 1. The feeding power mechanism 22 includes a feeding motor 221 and a feeding reducer 222. The feeding motor 221 and the feeding reducer 222 are connected for power transmission. The feeding reducer 222 is connected to one end of the feeding screw 21 and drives the feeding screw 21. The other end of the feeding screw 21 is output from the discharge port 12 of the hopper 1.

[0030] The material suction device 3 includes a material suction pipe 31, a cleaning valve 32, and an air replenishment valve 33, such as... Figure 3-4 The suction pipe 31 is arranged horizontally and is connected to the discharge port 12 of the hopper 1. The cleaning valve 32 and the air replenishment valve 33 are both located on the top of the suction pipe 31. The suction pipe 31 is provided with a first air inlet 34 connected to the cleaning valve 32 and a second air inlet 35 connected to the air replenishment valve 33.

[0031] The pigging valve 32 controls the opening and closing of the first air inlet 34.

[0032] The supplemental air valve 33 controls the amount of air intake and the on / off state of the second air intake port 35.

[0033] like Figure 1-2 The feeding device 2 is set to three sets, and correspondingly, the suction device 3 is also set to three sets.

[0034] like Figure 4 The pigging valve 32 includes a pigging valve cavity 321, a pigging plug 322, and a pigging valve cylinder 323. The bottom opening of the pigging valve cavity 321 is connected to the first air inlet 34. Several ventilation holes are provided on the pigging valve cavity 321. The pigging valve cylinder 323 is installed at the upper end of the pigging valve cavity 321. The pigging plug 322 is disposed in the pigging valve cavity 321. The piston rod of the pigging valve cylinder 323 passes downward into the pigging valve cavity 321 and connects with the pigging plug 322. The pigging valve cylinder 323 controls... The cleaning block 322 moves up and down in the cleaning valve cavity 321. When the cleaning block 322 moves to the bottom of the cleaning valve cavity 321, it blocks the first air inlet 34, which is then closed. When the cleaning block 322 moves upward, the first air inlet 34 is opened. When the suction pipe 31 is under negative pressure, external air enters the cleaning valve cavity 321 through a large number of ventilation holes and flows to the suction pipe 31 through the first air inlet 34.

[0035] like Figure 4The air supply valve 33 includes an air supply valve cavity 331, an air supply plug 332, an air supply valve cylinder 333, and an air regulating mechanism 334. The bottom opening of the air supply valve cavity 331 is connected to the second air inlet 35. An air inlet is provided on the side of the air supply valve cavity 331. An air regulating mechanism 334 for adjusting the air intake volume is installed at the air inlet of the air supply valve cavity 331. The air supply valve cylinder 333 is installed at the upper end of the air supply valve cavity 331. The air supply plug 332 is disposed in the air supply valve cavity 331. The piston rod of the air supply valve cylinder 333 extends downward into the air supply valve cavity 331. Connected to the air replenishment block 332, the air replenishment valve cylinder 333 controls the air replenishment block 332 to move up and down in the air replenishment valve cavity 331. When the air replenishment block 332 moves to the bottom of the air replenishment valve cavity 331, the air replenishment block 332 blocks the second air inlet 35, and the second air inlet 35 is closed at this time. When the air replenishment block 332 moves upward, the second air inlet 35 is opened. When the suction pipe 31 is under negative pressure, external air enters the air replenishment valve cavity 331 through the air adjustment mechanism 334 and flows to the suction pipe 31 through the second air inlet 35.

[0036] Combination Figure 1 , 4 8. The air regulating mechanism 334 includes a first air regulating plate 3341 and a second air regulating plate 3342. The first air regulating plate 3341 and the second air regulating plate 3342 have the same shape. With the center of the first air regulating plate 3341 as the center, four fan-shaped areas with the same angle are set. Multiple arc-shaped ventilation openings are opened in the fan-shaped areas. The arc-shaped ventilation openings of two adjacent fan-shaped areas have different radii and are staggered. The first air regulating plate 3341 is fixed at the air inlet of the air supply valve cavity 331, and the second air regulating plate 3342 rotates with the first air regulating plate 3341 on the same central axis. The air regulating mechanism 334 can adjust the air intake volume entering the suction pipe 31 through the air supply valve 33.

[0037] As shown in 3, 5, and 6, the mixing device 4 includes a mixing and dispersing device 41 and a mixing power mechanism 42. The mixing and dispersing device 41 is installed in the silo 1. The mixing power mechanism 42 is connected to the mixing and dispersing device 41 to transmit power. The mixing and dispersing device 41 includes a rotating shaft 411, three dispersing mechanisms 412, and two threaded push plates 413. The three dispersing mechanisms 412 are spaced apart on both sides of the two threaded push plates 413. The two threaded push plates 413 are wound around the rotating shaft 411, and the threads of the two threaded push plates 413 rotate in opposite directions. The dispersing mechanisms 412 are fixed to the rotating shaft 411. The dispersing mechanism 412 includes a dispersing plate 4121 and a dispersing rod 4122. The dispersing plate 4121 is vertically fixed to the rotating shaft 411, and the dispersing rod 4122 is vertically fixed to the dispersing plate 4121. The dispersing rod 4122 is parallel to the rotating shaft 411. Figure 3 , 5 The dispersing mechanism 412 disperses and mixes the material in the silo 1; for example Figure 1The feed inlet 11 is located in the middle of the upper part of the hopper 1. The material in the hopper 1 tends to accumulate in the middle. The threaded push plate 413 pushes the material in the hopper 1 to both sides to prevent the material from accumulating.

[0038] Combination Figure 3 , 5 6. The mixing and dispersing device 41 is located above the feeding screw 21, and the rotating shaft 411 is perpendicular to the feeding screw 21.

[0039] The stirring power mechanism 42 includes a stirring motor 421 and a stirring reducer 422. The stirring motor 421 and the stirring reducer 422 are connected for power transmission, and the stirring reducer 422 is connected for power transmission to the rotating shaft 411.

[0040] like Figure 3 The thread diameter of the feed screw 21 decreases from the right end to the left end. The end of the feed screw 21 with the smaller thread diameter is located in the suction pipe 31, and there is space between the thread of the feed screw 21 and the suction pipe 31.

[0041] like Figure 2-5 Two level gauges 5 are installed on the side wall of the silo 1. The level gauges 5 are used to detect the height of the material in the silo 1. The detection part of the level gauge 5 is located in the silo 1 and between two adjacent feeding screws 21. The height of the detection part of the level gauge 5 is higher than the height of the feeding screw 21.

[0042] Two ventilation openings 6 are provided at the top of the silo 1.

[0043] During operation, it is divided into a fast feeding mode and a slow, precise feeding mode; During rapid feeding, the air replenishment valve 33 is open, the cleaning valve 32 is closed, and the first air inlet 34 is closed. The air adjustment mechanism 334 of the air replenishment valve 33 can control the amount of replenished air. The suction pipe 31 is connected to the negative pressure suction device in the direction of the vacuum metering feeder. (Refer to...) Figure 3 A high negative pressure is generated in the suction pipe 31, which sucks away a large amount of material from the suction pipe 31, the discharge port 12, and the bottom of the hopper 1. The screw diameter at the left end of the feeding screw 21 is small, leaving a large space between it and the discharge port 12 and the suction pipe 31, so that the material can be quickly and in large quantities sucked away through the discharge port 12 in the fast feeding state.

[0044] In slow, precise feeding mode, open pigging valve 32, such as... Figure 3-4 The pigging valve cavity 321 has numerous ventilation holes, allowing a large amount of external gas to enter the suction pipe 31 through these holes. Consequently, the suction pipe 31 is unable to effectively remove material from the outlet 12 and the bottom of the hopper 1. Figure 4The feeding screw 21 pushes the material in the hopper 1 to below the first air inlet 34, and the feeding screw 21 controls the pushing amount. The airflow entering from the ventilation hole of the cleaning valve cavity 321 goes down through the first air inlet 34 and into the suction pipe 31. The airflow carries the material below the first air inlet 34 to the left end of the suction pipe 31, realizing slow and precise feeding.

[0045] In summary, the negative pressure feeder for quantitative material suction of the present invention can realize both fast feeding and slow precision feeding states, and is suitable for a variety of different feeding production processes. In the slow precision feeding state, it can stably and accurately control the material conveying amount. The feeding device and the suction device form a set, which can realize material conveying for multiple pipelines and different production needs.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A negative pressure feeder for quantitative material intake in a feeding machine, characterized in that, include: The hopper (1) is used to hold materials. The hopper (1) has an inlet (11) at the top and an outlet (12) at the bottom. Feeding device (2) is installed at the bottom of silo (1). The feeding device (2) includes a feeding screw (21) and a feeding power mechanism (22). The feeding screw (21) is installed through the bottom of silo (1). The feeding power mechanism (22) is located outside the silo (1), connected to one end of the feeding screw (21) and drives the feeding screw (21). The other end of the feeding screw (21) is output from the outlet (12) of the silo (1). The suction device (3) is connected to the outlet (12) of the silo (1) and includes a suction pipe (31), a cleaning valve (32), and an air replenishment valve (33). The suction pipe (31) is arranged horizontally, and both valves are set at the top of the suction pipe (31). The suction pipe (31) is connected to the outlet (12). The suction pipe (31) is provided with a first air inlet (34) connected to the cleaning valve (32) and a second air inlet (35) connected to the air replenishment valve (33). The pigging valve (32) controls the opening and closing of the first air inlet (34); The supplemental air valve (33) controls the amount of air intake and the on / off state of the second air inlet (35); The feeding device (2) is set to multiple sets, and correspondingly, the suction device (3) is also set to multiple sets.

2. A negative pressure feeder for quantitative material intake in a feeding machine according to claim 1, characterized in that, The cleaning valve (32) includes a cleaning valve cavity (321), a cleaning plug (322), and a cleaning valve cylinder (323). The bottom opening of the cleaning valve cavity (321) is connected to the first air inlet (34). Several ventilation holes are opened on the cleaning valve cavity (321). The cleaning valve cylinder (323) is installed at the upper end of the cleaning valve cavity (321). The cleaning plug (322) is set in the cleaning valve cavity (321). The piston rod of the cleaning valve cylinder (323) is connected to the cleaning plug (322) and moves up and down to control the opening and closing of the first air inlet (34).

3. A negative pressure feeder for quantitative material intake in a feeding machine according to claim 2, characterized in that, The air replenishment valve (33) includes an air replenishment valve cavity (331), an air replenishment block (332), an air replenishment valve cylinder (333), and an air regulating mechanism (334). The bottom opening of the air replenishment valve cavity (331) is connected to the second air inlet (35). An air inlet is provided on the side of the air replenishment valve cavity (331). An air regulating mechanism (334) for adjusting the air intake is installed at the air inlet of the air replenishment valve cavity (331). The air replenishment valve cylinder (333) is installed at the upper end of the air replenishment valve cavity (331). The air replenishment block (332) is located in the air replenishment valve cavity (331). The piston rod of the air replenishment valve cylinder (333) is connected to the air replenishment block (332) and moves up and down to control the opening and closing of the second air inlet (35).

4. A negative pressure feeder for quantitative material intake in a feeding machine according to claim 3, characterized in that, The air regulating mechanism (334) includes a first air regulating plate (3341) and a second air regulating plate (3342). The first air regulating plate (3341) and the second air regulating plate (3342) have the same shape. With the center of the first air regulating plate (3341) as the center, n fan-shaped areas with the same angle are set, where n is an even number. Multiple arc-shaped ventilation openings are opened in the fan-shaped areas. The arc-shaped ventilation openings of two adjacent fan-shaped areas have different radii and are staggered. The first air regulating plate (3341) is fixed at the air inlet of the air supply valve cavity (331), and the second air regulating plate (3342) rotates with the first air regulating plate (3341) on the same central axis.

5. A negative pressure feeder for quantitative material intake in a feeding machine according to claim 1, characterized in that, It also includes a stirring device (4), which includes a stirring and dispersing device (41) and a stirring power mechanism (42). The stirring and dispersing device (41) is installed in the silo (1). The stirring power mechanism (42) is connected to the stirring and dispersing device (41) to transmit power. The stirring and dispersing device (41) includes a rotating shaft (411), multiple dispersing mechanisms (412), and two threaded push plates (413). The two threaded push plates (413) are wound around the rotating shaft (411). The threads of the two threaded push plates (413) rotate in opposite directions. The dispersing mechanisms (412) are fixed on the rotating shaft (411) and are located on both sides of the threaded push plates (413). The mixing and dispersing device (41) is located above the feeding screw (21), and the rotating shaft (411) is perpendicular to the feeding screw (21).

6. A negative pressure feeder for quantitative material intake in a feeding machine according to claim 5, characterized in that, The dispersing mechanism (412) includes a dispersing plate (4121) and a dispersing rod (4122). The dispersing plate (4121) is vertically fixed on the rotating shaft (411), and the dispersing rod (4122) is vertically fixed on the dispersing plate (4121). The dispersing rod (4122) is parallel to the rotating shaft (411).

7. A negative pressure feeder for quantitative material intake in a feeding machine according to claim 1, characterized in that, The thread diameter of the feeding screw (21) decreases from one end to the other. The end of the feeding screw (21) with the smaller thread diameter is located in the suction pipe (31), and there is space between the thread of the feeding screw (21) and the suction pipe (31).

8. A negative pressure feeder for quantitative material intake in a feeding machine according to claim 5, characterized in that, The feeding power mechanism (22) includes a feeding motor (221) and a feeding reducer (222). The feeding motor (221) and the feeding reducer (222) are connected for power transmission, and the feeding reducer (222) is connected for power transmission to the feeding screw (21). The stirring power mechanism (42) includes a stirring motor (421) and a stirring reducer (422). The stirring motor (421) and the stirring reducer (422) are connected for power transmission, and the stirring reducer (422) is connected for power transmission to the rotating shaft (411).

9. A negative pressure feeder for quantitative material intake in a feeding machine according to claim 1, characterized in that, Multiple level gauges (5) are installed on the side wall of the silo (1). The detection part of the level gauge (5) is located in the silo (1) and between two adjacent feeding screws (21). The height of the detection part of the level gauge (5) is higher than the height of the feeding screw (21).

10. A negative pressure feeder for quantitative material intake in a feeding machine according to claim 1, characterized in that, Two ventilation openings (6) are provided at the upper end of the hopper (1).

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