Automatic powder metering and feeding system

Abstract

An automatic powder metering and feeding system comprises an ejector (7), a metering and weighing device (1), a variable-frequency rotary discharger (2) and a PLC (programmable logic controller) control background (9), and is characterized in that the ejector (7) is a cylindrical base of the metering and feeding system, the metering and weighing device is a conical stock bin, an upper opening of the variable-frequency rotary discharger (2) is connected with a bottom opening of the conical stock bin, and a lower opening of the variable-frequency rotary discharger (2) is connected with the PLC control background (9). A lower opening of the variable-frequency rotary discharger (2) is connected with the top of the ejector (7) through a second cloth bag (6); and the PLC control background (9) is respectively communicated with the power frequency rotary discharger (3), the stirring motor, the air hammer, the cantilever weight sensor, the rotating shaft (1.3), the pressure transmitter (7.3) and the Roots blower (8) through communication lines. The automatic powder metering and feeding system has the advantages that the feeding flow of the powder is intelligently controlled, the airflow ejector conveys the powder away, and intelligent control over powder conveying is achieved.

Description

Technical Field

[0001] The utility model relates to a powder conveying device, specifically an automatic metering and feeding system for powder. Background Art

[0002] At present in China, for the conveying of powders with a particle size of about 50 - 100 μm, the degree of automation in the control of conveying flow rate is not high, and there are many defects in reliability during the conveying process. Usually, in the technical link of conveying flow rate control, most of the time, the frequency of a rotary ash discharge valve is manually adjusted to increase or decrease the conveying volume, and accurate conveying flow rate data cannot be obtained; due to the poor fluidity of ultra-fine powders, in the current conveying process, there are often situations where the powder is air-suspended at the funnel, with powder above but no powder discharging.

[0003] Since the powder is pneumatically conveyed, in the past, an air lock was set under the variable-frequency rotary discharge valve below to prevent the wind from below from disturbing the air lock. However, due to poor sealing effect, the flow field cannot meet the design requirements, that is, in actual operation, the air power sent by the Roots blower pushes up from the place where the powder falls, resulting in poor discharging and inability to normally convey the powder. This is a common problem in the current industry.

[0004] Therefore, the known pneumatic conveying methods for powders have the above-mentioned various inconveniences and problems. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a safe and reliable automatic metering and feeding system for powder.

[0006] To achieve the above purpose, the technical solution of the utility model is:

[0007] An automatic metering and feeding system for powder, including an ejector, a metering and weighing device, a variable-frequency rotary discharger, and a PLC control background, characterized in that:

[0008] The ejector is the cylindrical base of the metering and feeding system. In the radial pipeline on one side of the cylindrical base, a Venturi valve, a check valve, and a pressure transmitter are sequentially arranged. A Roots blower is also arranged in the pipeline where the pressure transmitter is located. On the other side of the cylindrical base, a jet output pipeline is provided;

[0009] The metering and weighing device is a conical silo. A rotating shaft is provided at the center of the conical silo. A stirring motor is provided at the top of the rotating shaft. Several cantilever weight sensors are provided in the middle of the outer side wall of the conical silo. A stirring support arm with an inverted trapezoidal cross-section is provided in the middle part of the rotating shaft. A spiral blade is provided below the stirring support arm at the lower part of the rotating shaft. An air hammer is provided at the upper part of the outer side wall of the conical silo; the top opening of the conical silo is connected to the industrial frequency rotary discharger arranged above through the first cloth bag on one side of the platform, and a spare flexible cloth bag is provided on the other side of the platform; an insertion valve is provided above the industrial frequency rotary discharger, and a powder storage hopper is connected above the insertion valve;

[0010] The upper opening of the variable frequency rotary discharger is connected to the bottom opening of the conical silo, and the lower opening of the variable frequency rotary discharger is connected to the top of the ejector through the second cloth bag;

[0011] The PLC control background communicates with the industrial frequency rotary discharger, stirring motor, air hammer, cantilever weight sensor, rotating shaft, pressure transmitter, and Roots blower respectively through communication wires.

[0012] The powder automatic metering and feeding system of the present utility model can also adopt the following technical measures to further realize.

[0013] In the aforementioned powder automatic metering and feeding system, the rotating shaft is arranged from the top opening of the conical silo to the bottom opening of the conical silo.

[0014] In the aforementioned powder automatic metering and feeding system, the ejector is an ejector assembly that can generate negative pressure for the feeding system.

[0015] In the aforementioned powder automatic metering and feeding system, the elevation angle of the conical silo is greater than 70°.

[0016] In the aforementioned powder automatic metering and feeding system, the air hammer is a vibrating air hammer, which improves the fluidity of the powder and prevents the powder from adhering to the side wall of the silo.

[0017] In the aforementioned powder automatic metering and feeding system, the cloth bag is a flexible breathable cloth bag.

[0018] In the aforementioned powder automatic metering and feeding system, the venturi valve is provided with an air flow adjustment mechanism, which can be adjusted according to the powder flow rate above.

[0019] After adopting the above technical solutions, the powder automatic metering and feeding system of the present utility model has the following advantages:

[0020] 1. The automatic device of the feeding system has intelligent control over the feeding flow rate of the powder;

[0021] 2. The air flow ejector is equipped with a venturi valve to adjust the wind speed to send away the powder;

[0022] 3. Achieved intelligent control of powder conveying, solving the problem that the powder in the variable-frequency rotary discharger does not fall due to being disturbed by the wind below. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the metering and weighing device according to the embodiment of the present invention.

[0024] In the figure: 1 is the metering and weighing device, 1.1 is the stirring motor, 1.2 is the cantilever weight sensor, 1.3 is the rotating shaft, 1.4 is the stirring arm, 1.5 is the spiral blade, 1.6 is the air hammer, 1.7 is the flexible cloth bag, 2 is the variable-frequency rotary discharger, 3 is the power-frequency rotary discharger, 4 is the plug valve, 5 is the first cloth bag, 6 is the second cloth bag, 7 is the injector, 7.1 is the one-way valve, 7.2 is the Venturi valve, 7.3 is the pressure transmitter, 8 is the Roots blower, 9 is the PLC control background, and 10 is the powder storage hopper. Specific Embodiments

[0025] The present invention will be further described below in conjunction with the embodiments and their accompanying drawings.

[0026] Embodiment 1

[0027] The powder automatic metering and feeding system of the present invention includes an injector 7, a metering and weighing device 1, a variable-frequency rotary discharger 2, and a PLC control background 9.

[0028] Now please refer to Figure 1 , Figure 1 It is a schematic structural diagram of the metering and weighing device according to the embodiment of the present invention. As shown in the figure, the metering and weighing device 1 is provided with a weighing cantilever weight sensor 1.2 on the conical silo, which collects the silo data in real time, calculates the powder conveying flow rate (kg / h), and feeds it back to the on-site instrument with communication function, and then wires the instrument to the PLC terminal. The instrument information is displayed on the PLC control background 9, and the program is programmed to have the function of online remote range change; the PLC can set program control according to the terminal working conditions. That is, if the terminal needs to increase the feeding amount, the variable-frequency rotary discharger 2 below the silo will automatically increase the conveying speed according to the instructions of the background. The first cloth bag 5 is connected to the inlet of the power-frequency rotary discharger 3 and the metering and weighing device 1.

[0029] Set a replenishment program in the PLC. When the weight of the powder silo is lower than 15% of the full load weight, the power-frequency rotary discharger 3 under the upper powder storage hopper 10 will be automatically started, and the power-frequency rotary discharger will be intelligently started and stopped by the PLC control intermediate relay.

[0030] An ejector 7 is installed at the bottom to convey the powder delivered by the variable-frequency rotary unloader to the terminal. The ejector needs to be equipped with a venturi valve to adjust the air flow rate sent by the Roots blower 8. The greater the speed, the higher the negative pressure attraction on the powder delivered by the variable-frequency rotary unloader. On the contrary, if the air flow speed in the venturi valve is low, the air flow will flow upward to fill the upper space, blocking the powder falling from the upper variable-frequency rotary unloader and causing blockage. A check valve needs to be installed at the front section of the venturi valve because when the air source stops, the powder will flow back from the terminal and clog the ejector, causing blockage.

[0031] To solve the problems of poor powder fluidity in the powder bin, easy adhesion to the side wall, and easy formation of hollow cavities inside the powder that prevent it from flowing, the elevation angle of the conical hopper of the bin is designed to 70° to ensure that the powder can flow down more easily under its own gravity. A stirring and rotating shaft 1.3 is set in the center of the conical powder bin to break the hollow cavities inside the powder. The rotating shaft of the stirring device extends from above the powder bin to the outlet of the conical hopper of the bin. The stirring device is powered by a stirring motor 1.1 above the powder bin, and the motor speed is reduced to about 10 r / min. Too high a rotation speed will cause the powder to fly up and suspend, and at this time, the powder cannot flow downward to the lower variable-frequency rotary unloader under the action of gravity. Multiple stirring arms 1.4 are arranged on the rotating shaft of the stirring device, and the arms can be arranged in various ways to form a turbulent flow for the powder within the maximum space range, greatly increasing the fluidity of the powder. An air hammer 1.6 controlled by a solenoid valve is installed on the outer wall of the bin. The solenoid valve is controlled by a PLC program to supply air to hammer the bin at regular intervals to break the powder adhering to the surrounding of the bin. At the same time, a spiral blade 1.5 can be set at the end of the stirring and rotating shaft. The spiral blade is an integrated structure with the rotating shaft. When the spiral shaft rotates, the powder is forcibly conveyed into the lower variable-frequency rotary unloader below. The lower variable-frequency unloader continues to send the powder to the lower ejector according to the set speed. The above technical improvements are all aimed at improving the fluidity of the powder.

[0032] The air flow is provided by a Roots blower at the front end or directly uses compressed air. A pressure transmitter is installed on the air flow pipeline behind the Roots blower and outputs to the PLC. The air volume of the Roots blower is selected according to the maximum conveying volume required at the terminal. When the variable-frequency rotary unloader is stopped on the PLC, or when the deformable rotary unloader stops working due to other reasons, the air source Roots blower automatically stops, and the stirring motor of the powder bin and the upper industrial-frequency rotary unloader also automatically stop. When the value of the pressure transmitter is less than the set value, both the upper variable-frequency rotary ash valve and the upper industrial-frequency rotary unloader stop working. This control logic is to prevent the system from feeding powder in a state without air source, causing equipment blockage and damage.

[0033] The utility model has substantial features and remarkable technical progress. The automatic powder metering and feeding system of the utility model comprises an ejector assembly capable of generating negative pressure. The weighing device is provided with weight sensors around the powder bin. The replenishment of the powder in the bin is controlled by a power-frequency rotary discharge valve above. When the weight of the bin is lower than the set value, the rotary discharge valve above opens; when it is higher than the set value, the rotary discharge valve above closes. The powder is stored in a large-capacity hopper above, and a knife gate valve is arranged below the hopper. The knife gate valve is normally open and only closes when the equipment below needs to be overhauled. A flexible air-permeable cloth bag 6 is connected between the power-frequency rotary discharge valve above and the bin below to balance the atmospheric pressure. The start and stop actions of the motor of the power-frequency discharger are communicated by a relay and a PLC, and intelligent control can be achieved by PLC programming. The weighing device can count the flow rate (kg / h) of the variable-frequency rotary discharge valve below the bin according to the change of the weight of the bin. When the terminal needs to increase the flow rate, the PLC automatically increases the frequency of the variable-frequency discharge valve below to accelerate the rotary discharge speed. When the terminal needs to reduce the flow rate, the frequency of the variable-frequency discharge valve below can be reduced to reduce the rotary discharge speed. The frequency converter of the motor of the variable-frequency discharge valve is communicated with the PLC, and intelligent control can be achieved by PLC programming. The weighing device is provided with weight sensors around the powder bin and outputs to an intermediate instrument. The intermediate instrument is communicated with the PLC, and the range and alarm signal can be programmed and set on the PLC. A spiral auger blade is arranged at the hopper opening of the bin. The spiral auger blade is fixed on the rotating shaft to forcefully output the powder, and the motor of the spiral shaft is decelerated to a low speed to slowly stir the powder continuously. A flexible air-permeable cloth bag is connected between the variable-frequency rotary discharge valve below the bin and the ejector pump below. A venturi valve for adjusting the air flow speed is arranged behind the ejector check valve. The venturi valve is equipped with an air flow adjustment mechanism, and the air flow speed can be manually adjusted in advance according to the amount of the powder flow rate above.

[0034] The above embodiments are only for illustrating the utility model, rather than limiting the utility model. Those skilled in the relevant technical fields can make various transformations or changes without departing from the spirit and scope of the utility model. Therefore, all equivalent technical solutions should also belong to the scope of the utility model and should be defined by each claim.

Claims

1. An automatic powder metering and feeding system, comprising an ejector (7), a metering and weighing device (1), a variable-frequency rotary discharger (2), and a PLC control background (9), characterized in that: The ejector (7) is a cylindrical base of the metering and feeding system. In the radial pipeline on one side of the cylindrical base, a Venturi valve (7.2), a check valve (7.1), and a pressure transmitter (7.3) are successively arranged. A Roots blower (8) is also arranged in the pipeline where the pressure transmitter is located. On the other side of the cylindrical base, there is an ejection output pipeline; The metering and weighing device (1) is a conical silo. A rotating shaft (1.3) is arranged at the center of the conical silo. A stirring motor (1.1) is arranged at the top of the rotating shaft. Several cantilever weight sensors (1.2) are arranged in the middle of the outer side wall of the conical silo. A stirring support arm (1.4) with an inverted trapezoidal cross-section is arranged in the middle part of the rotating shaft. A spiral blade (1.5) is arranged below the stirring support arm at the lower part of the rotating shaft. A pneumatic hammer (1.6) is arranged at the upper part of the outer side wall of the conical silo; The top opening of the conical silo is connected to the industrial-frequency rotary discharger (3) arranged above through the first cloth bag (5) on one side of the platform, and a spare flexible cloth bag (1.7) is arranged on the other side of the platform; An insertion plate valve (4) is arranged above the industrial-frequency rotary discharger (3), and a powder storage hopper (10) is connected above the insertion plate valve; The upper opening of the variable-frequency rotary discharger (2) is connected to the bottom opening of the conical silo, and the lower opening of the variable-frequency rotary discharger (2) is connected to the top of the ejector (7) through the second cloth bag (6); The PLC control background (9) communicates with the industrial-frequency rotary discharger (3), the stirring motor (1.1), the pneumatic hammer (1.6), the cantilever weight sensor (1.2), the rotating shaft (1.3), the pressure transmitter (7.3), and the Roots blower (8) respectively through communication wires.

2. The powder automatic metering and feeding system according to claim 1, wherein The rotating shaft is arranged from the top opening of the conical silo to the bottom opening of the conical silo.

3. The powder automatic metering and feeding system according to claim 1, characterized in that, The ejector (7) is an ejector assembly that can generate negative pressure in the feeding system.

4. The automatic powder metering and feeding system according to claim 1, wherein The elevation angle of the conical silo is greater than 70°.

5. The powder automatic metering and feeding system according to claim 1, characterized in that, The pneumatic hammer is a vibrating pneumatic hammer, which improves the fluidity of the powder and prevents the powder from adhering to the side wall of the silo.

6. The automatic powder metering and feeding system according to claim 1, wherein The cloth bag is a flexible breathable cloth bag.

7. The powder automatic metering and feeding system according to claim 1, characterized in that, The Venturi valve is provided with an air flow adjustment mechanism, which can be adjusted according to the powder flow rate above.

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