An experimental device for detecting characteristics of a stirring paddle

Abstract

The utility model relates to stirring experimental device technical field and disclose an experimental device of stirring paddle characteristic detection, including work table, be provided with stirring system, gas supply system, measuring system and control unit on work table, this experimental device of stirring paddle characteristic detection, the collaborative work of stirring system, gas supply system and measuring system in the device, effectively solve the limitation problem of traditional device, and the speed regulating motor of stirring system drives the stable operation of stirring paddle, cooperate air compressor, buffer tank and rotor flowmeter of gas supply system, can stable control gas flow, and the bubble is cut into small size by stirring paddle and makes it even dispersion, eliminates the interference of gas phase to measurement, the light -electricity switch, electric energy meter and so on parts of measuring system, combine the dynamic compensation algorithm of PLC controller, reduce the measurement error of speed and power greatly, still can through digital viscosimeter can adapt the liquid system of many viscosity range, cover the detection demand of gas -liquid two -phase flow, break the limitation of traditional device single system.

Description

Technical Field

[0001] This utility model relates to the technical field of stirring experimental devices, specifically an experimental device for detecting the characteristics of a stirring paddle. Background Technology

[0002] Stirring is a core unit operation in industries such as chemical, petroleum, pharmaceutical, food, and wastewater treatment. It is widely used in processes such as mixing miscible liquids, dispersing immiscible liquids, gas-liquid contact, suspending solid particles, and enhancing heat transfer / chemical reactions. In the design and optimization of stirring equipment, stirring power is a key parameter for judging the stirring effect. Stirring power is usually obtained by experimentally measuring the power curve, that is, the relationship curve between the dimensionless power Np and the stirring Reynolds number Re.

[0003] However, traditional impeller characteristic testing devices have many shortcomings and cannot meet the requirements of high-precision and wide-range experiments. Traditional devices use mechanical instrument readings, which are easily affected by factors such as operator visual errors and reading response speed, resulting in low data accuracy. At the same time, traditional devices lack a real-time data acquisition system and cannot record the dynamic changes of speed and power during stirring, further reducing measurement accuracy. Traditional devices are only suitable for single liquid systems with viscosity of 0~10000mPa·s, and their effect on measuring the power curve of gas and liquid two-phase flow is extremely poor. On the one hand, it is impossible to stably control the gas flow rate, and on the other hand, it is difficult to eliminate the interference of gas phase on the measurement signal. Traditional devices require operators to manually adjust the motor speed and gas flow rate, which not only has large operating errors, but also poses a risk of equipment damage due to sudden increase in motor speed. In addition, when conducting experiments with and without baffles, two stirring tanks with different structures are required, resulting in large equipment footprint and low experimental efficiency. In view of this, an experimental device for testing impeller characteristics is proposed. Utility Model Content

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides an experimental device for detecting the characteristics of a stirring paddle, thus solving the problem of inaccurate experimental measurement results of the stirring paddle.

[0005] (II) Technical Solution To achieve the above objectives, this utility model provides the following technical solution: an experimental device for detecting the characteristics of a stirring paddle, comprising a worktable, on which a stirring system, an air supply system, a measuring system, and a control unit are provided; The mixing system includes a mixing tank, a vertical plate, a speed-regulating motor, a fixed roller, and a mixing paddle. The mixing tank is fixedly installed on the upper surface of the workbench, and the vertical plate is fixedly installed on the upper surface of the workbench. The variable speed motor is fixedly installed on the front surface of the workbench, the fixed roller is fixedly installed on the output end of the variable speed motor, and the stirring paddle is fixedly sleeved on the outer surface of the fixed roller. Preferably, the air supply system includes an air compressor, a buffer tank, and a rotor flow meter; The air compressor is fixedly installed on the upper surface of the workbench base plate, and the buffer tank is fixedly installed on the right surface of the workbench upright plate. The air compressor is connected to the buffer tank through a connecting pipe. The rotor flow meter is installed on the outer surface of the buffer tank.

[0006] Preferably, the measurement system includes a photoelectric switch, an electricity meter, a digital viscometer, and a temperature sensor. The photoelectric switch is fixedly installed in the inner wall of the stirring tank, the electricity meter is fixedly installed in the inner wall of the measuring equipment housing, the digital viscometer is fixedly installed in the inner wall of the measuring equipment housing, and the temperature sensor is fixedly installed in the inner wall of the measuring equipment housing.

[0007] Preferably, the control unit includes a PLC controller, which is fixedly installed on the upper surface of the workbench. The PLC controller is electrically connected to a photoelectric switch, an electricity meter, a digital viscometer, and a temperature sensor.

[0008] Preferably, the inner wall of the mixing tank is provided with a detachable baffle. The detachable baffle is connected to the inner wall of the mixing tank through a slot. The slot is opened in the shape of a dovetail groove, and the detachable baffle is provided with a corresponding locking block.

[0009] (III) Beneficial Effects Compared with the prior art, this utility model provides an experimental device for detecting the characteristics of a stirring paddle, which has the following beneficial effects: 1. This experimental apparatus for detecting the characteristics of agitators features a coordinated stirring system, an air supply system, and a measurement system. This effectively addresses the limitations of traditional apparatuses. The speed-regulating motor of the stirring system drives the agitator to operate stably. Combined with the air compressor, buffer tank, and rotor flow meter of the air supply system, the gas flow rate can be stably controlled. The agitator cuts the bubbles into tiny sizes and disperses them evenly, eliminating interference from the gas phase in the measurement. The photoelectric switch, energy meter, and other components of the measurement system, combined with the dynamic compensation algorithm of the PLC controller, significantly reduce the measurement errors of speed and power. Furthermore, the digital viscometer can adapt to liquid systems with multiple viscosity ranges, covering the detection needs of gas-liquid two-phase flows and breaking the limitations of traditional apparatuses that rely on a single system.

[0010] 2. The experimental apparatus for testing the characteristics of the stirring paddle adopts a modular and detachable structure, which significantly improves practicality and economy. The PLC controller of the control unit is electrically connected to each measuring component to realize automatic parameter acquisition and adjustment. This avoids errors caused by manual operation and prevents the risk of equipment damage caused by sudden increase in motor speed. The detachable baffle in the stirring tank is installed through a slot, which can flexibly switch between experiments with and without baffles without replacing the stirring tank, reducing the equipment footprint. At the same time, the layout of each system component is reasonable and relatively independent, which facilitates daily maintenance and repair. While improving experimental efficiency, it greatly reduces equipment investment and long-term use costs. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the experimental apparatus for detecting the characteristics of the stirring paddle of this utility model. Figure 2 This is a schematic diagram of the workbench structure of this utility model; Figure 3 This is a schematic diagram of the internal structure of the mixing tank of this utility model; Figure 4 This is a schematic diagram of the internal structure of the photoelectric switch of this utility model.

[0012] In the diagram: 1. Workbench; 2. Air compressor; 3. Buffer tank; 4. Rotor flow meter; 5. Mixing tank; 6. Vertical plate; 7. Speed-regulating motor; 8. Fixed roller; 9. Mixing paddle; 10. Removable baffle; 11. Photoelectric switch; 12. PLC controller; 13. Energy meter; 14. Digital viscometer; 15. Temperature sensor. Detailed Implementation

[0013] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0014] Please see Figure 1-4 This utility model provides a new technical solution: an experimental device for detecting the characteristics of a stirring paddle, including a workbench 1, on which a stirring system, an air supply system, a measuring system and a control unit are provided; The stirring system includes a stirring tank 5, a vertical plate 6, a speed-regulating motor 7, a fixed roller 8, and a stirring paddle 9. The mixing tank 5 is fixedly installed on the upper surface of the workbench 1, and the vertical plate 6 is fixedly installed on the upper surface of the workbench 1. Among them, the speed-regulating motor 7 is fixedly installed on the front surface of the workbench 1, the fixed roller 8 is fixedly installed on the output end of the speed-regulating motor 7, and the stirring paddle 9 is fixedly sleeved on the outer surface of the fixed roller 8. Furthermore, the air supply system includes an air compressor 2, a buffer tank 3, and a rotor flow meter 4; The air compressor 2 is fixedly installed on the upper surface of the base plate of the workbench 1, and the buffer tank 3 is fixedly installed on the right surface of the vertical plate of the workbench 1. The air compressor 2 is connected to the buffer tank 3 through a connecting pipe. The rotor flow meter 4 is installed on the outer surface of the buffer tank 3.

[0015] Furthermore, the measurement system includes a photoelectric switch 11, an energy meter 13, a digital viscometer 14, and a temperature sensor 15. The photoelectric switch 11 is fixedly installed in the inner wall of the stirring tank 5, the energy meter 13 is fixedly installed in the inner wall of the measuring equipment housing, the digital viscometer 14 is fixedly installed in the inner wall of the measuring equipment housing, and the temperature sensor 15 is fixedly installed in the inner wall of the measuring equipment housing.

[0016] Furthermore, the control unit includes a PLC controller 12, which is fixedly mounted on the upper surface of the workbench 1. The PLC controller 12 is electrically connected to the photoelectric switch 11, the electricity meter 13, the digital viscometer 14, and the temperature sensor 15.

[0017] Furthermore, the detachable baffle 10 is fixedly installed in the inner wall of the mixing tank 5. The detachable baffle 10 is connected to the inner wall of the mixing tank 5 through a slot. The slot is opened in the shape of a dovetail groove, and the detachable baffle 10 is provided with a corresponding locking block.

[0018] An experimental apparatus for testing the characteristics of a stirring paddle has the following steps for use: S1: Check device status: Confirm that there is no residual material in the mixing tank and that valves VA01~VA06 are all closed; check that the power connections of the air compressor, speed regulating motor, and viscometer are normal; Prepare experimental materials: Weigh an appropriate amount of sodium carboxymethyl cellulose, dissolve it in deionized water, stir well, and pour it into a stirring tank. The liquid level should not exceed 80% of the height of the stirring tank. Equipment initialization: Turn on the main power and control power in sequence, enter the software operation interface, and confirm that each instrument displays 0 or the initial value; S2: Start the viscometer: Click the viscometer control on the software interface to start it. Take the CMC solution through the VA06 sampling valve, measure and record the viscosity and experimental temperature. Adjusting motor speed: Click on the speed control motor, start, and slowly adjust the motor output signal to make the speed start from 100r / min, take 1 point at 20r / min intervals, and take a total of 10~12 points; Data recording: After each speed adjustment, wait 2-3 minutes until the data stabilizes, click on the software data recording to save the current speed, and at the same time observe the flow pattern in the mixing tank and record the phenomenon.

[0019] S3: Start the air supply system: Click the air compressor control in the software to start it, turn on VA01 (turn off after 10 seconds of exhaust); turn on VA02, and after the pressure displayed on PI01 stabilizes, turn on VA03 and VA04. Adjusting the gas flow rate: Adjust the air flow rate to the target value using a rotor flow meter and record the flow rate value; Repeated speed adjustment and data recording: The operation is the same as the liquid-liquid system. Take 10 to 12 speed points from 100 to 500 r / min. After each point stabilizes, record the speed, voltage, and current, and additionally record the liquid level in the stirring tank. End gas supply: After completing the measurement, close valves VA03 and VA04, click the air compressor control to stop, and open VA02 to release the remaining gas in the buffer tank.

[0020] When the air pressure decreases, the compressed air inside the tank expands and releases pressure, eventually stabilizing the outlet air pressure of the buffer tank at 0.6±0.05MPa, providing a stable air source for subsequent flow control. The main body of the rotor flowmeter is a conical tube, inside which is a float that can move up and down. When compressed air flows from bottom to top through the conical tube, the float is subjected to upward fluid impact force and buoyancy, as well as downward gravity and friction force. When the flow rate is stable, the float remains stationary at a certain height, which has a linear relationship with the flow rate. The flow-height curve has been calibrated for air medium before leaving the factory. Operators can read the gas flow rate by observing the float height and control the flow rate to the target value by adjusting the opening of the VA03 valve. The gas distributor is installed at the bottom of the mixing tank, and the gas distributor is installed around the center of the mixing shaft, in 2-3... The concentric circular distribution of small holes is suitable for turbine-type agitators. It can match the radial flow field generated by the rotation of the blades, allowing the gas to be quickly broken up by the blades. The surface is uniformly opened with Φ2mm small holes. When the stabilized compressed air passes through the small holes, it will be cut into tiny bubbles of Φ1~2mm. Under the action of the flow field generated by the agitator, these bubbles will be uniformly dispersed in the liquid, avoiding the power measurement error caused by the traditional "large bubble agglomeration". Hardware signal generation: The encoder disk is mounted on the motor shaft above the agitator and rotates synchronously with the agitator; the transmitter and receiver of the photoelectric switch are located on both sides of the encoder disk and aligned with the opening area of ​​the encoder disk. When the encoder disk rotates, the opening allows the light signal to pass through, while the disk body blocks the light signal, thus forming a continuous pulse signal. Dynamic compensation algorithm: The transparent plexiglass stirring tank will refract the LED light signal, causing some pulses to be lost. To eliminate this interference, the PLC presets a speed and reference pulse frequency comparison table, compares the real-time collected pulse frequency with the reference frequency, calculates the pulse loss ratio, and then fills in the lost pulses proportionally, ultimately reducing the speed measurement error. Signal stability assurance: The PLC can adjust the LED emission power of the photoelectric switch through software. At low speeds, the emission power is increased to enhance the light signal and avoid pulse loss. At high speeds, the emission power is reduced to avoid signal saturation at the receiving end, ensuring signal stability across the entire speed range. Data Acquisition: The DJSF series energy meter is electrically connected to the armature of the speed-regulating motor, supporting high-precision sampling of DC 0~1000V voltage and 600A current. The energy meter transmits the collected voltage and current data to the PLC controller in real time via the Modbus-RTU protocol. The motor output power is divided into effective stirring power and motor copper losses, which need to be corrected using a formula to obtain the actual stirring power, which is the motor input power. I²R represents the motor copper losses. Relying on the energy meter's ±0.2-level sampling accuracy, combined with formula correction, the measurement error of the stirring power is much higher than that of traditional devices. The digital viscometer uses a rotor rotation shear method. Personnel select a suitable rotor based on the fluid viscosity. When the rotor rotates at a fixed speed in the liquid, it experiences shear resistance from the liquid. This resistance torque is proportional to the viscosity. The viscometer converts the resistance torque into a viscosity value via a torque sensor and transmits it to the PLC for recording. A Pt100 temperature sensor is inserted into the stirring tank, and its resistance value changes with temperature. The PLC calculates the experimental temperature using a resistance-temperature conversion formula to correct for the liquid's density and viscosity. A buffer tank is installed on top to monitor the air pressure inside the tank in real time. When the air pressure is below 0.5 MPa, the PLC will issue an insufficient air pressure alarm on the software interface, prompting the operator to check the air compressor's operating status.

[0021] The experimental setup for the characteristics of the stirred impeller revolves around the logic of "stirring to establish a flow field → gas supply (gas-liquid experiment) → parameter acquisition → closed-loop control". Each system works in sync to achieve the experimental function: First, the stirring system is started. The speed-regulating motor drives the six-bladed disc turbine impeller to rotate (0~1500rpm stepless speed regulation) through the coupling. When the blades rotate, radial flow and shear force are generated. The radial flow rises along the wall of the stirring tank and then sinks from the center, forming a "radial-axial circulating flow". If it is necessary to switch the experimental conditions, the operator can switch between "with baffle / without baffle" by manually inserting and removing the baffle (without tools). With baffles, the fluid swirls and a composite flow is formed, improving mixing efficiency. Without baffles, the fluid flows mainly in a circular motion, eliminating the need to replace the mixing tank equipment.

[0022] If a gas-liquid experiment is to be conducted, the air supply system must be activated simultaneously: the air compressor first compresses the air to 0.7 MPa. After the compressed air enters the 5L buffer tank, pressure fluctuations are balanced through "air storage and depressurization" to stabilize the outlet air pressure at 0.6 ± 0.05 MPa. The stabilized air then flows through the rotor flowmeter. The float is balanced by the fluid impact force and gravity. The operator controls the flow rate between 0.25 and 2.5 m³ / h by adjusting the valve opening. 3 / h (accuracy ±5%); finally, the air is cut into Φ1~2mm microbubbles by the Φ2mm porous distributor at the bottom of the stirring tank, and is evenly dispersed under the action of the stirring flow field to avoid large bubble agglomeration affecting the measurement.

[0023] While the stirring system is running and the gas supply system (for gas-liquid experiments) is distributing gas, the measurement system simultaneously collects various experimental parameters: a photoelectric switch is aligned with a 6-hole equidistant encoder disk above the stirring paddle; as the encoder disk rotates with the stirring paddle, it alternately blocks the light signal, generating a pulse signal; to address the light refraction interference from the transparent stirring tank wall, the PLC presets a "speed-reference pulse frequency" lookup table (e.g., 100 r / min corresponds to 10 Hz), and by comparing the actual frequency with the reference frequency, it fills in the missing pulses. It can also adjust the LED emission power (5~20 mW) to ensure signal stability, ultimately achieving a speed error ≤ ±1 r / min; the power meter collects the motor voltage and current in real time, transmitting them to the PLC via the Modbus-RTU protocol; the PLC calculates the effective stirring power, and after correcting for motor copper losses, the power error is ≤ ±3%; in addition, the viscometer measures 10~10 rpm using rotor shear force. 5 The fluid viscosity is measured in mPa·s (accuracy ±2%). The Pt100 temperature sensor acquires the temperature through resistance-temperature conversion (to correct for fluid density and viscosity). The pressure gauge monitors the pressure of the buffer tank (0~1MPa) and triggers an alarm when it is below 0.5MPa.

[0024] The control unit automates the entire experimental process: after the operator issues commands such as "start motor," "adjust speed," and "start air compressor" through the software interface, the PLC drives the corresponding actuators to perform actions, such as stepless speed regulation of the motor through PWM pulse width modulation; the PLC receives a measurement signal every 100ms, converts it into displayable parameters such as speed, power, and viscosity, and automatically calculates the stirring Reynolds number to generate raw Np-Re curve data. The data is stored in "time-parameter" format (up to 1000 sets can be stored) and supports exporting to Excel via USB flash drive; at the same time, the PLC monitors the experimental status in real time. If the current exceeds 1.5A (motor overload), the temperature exceeds 40℃, or the flow rate exceeds the range, it will immediately cut off the power to the corresponding equipment, and the interface will display a fault code (such as "E01: motor overload") to avoid equipment damage.

[0025] Taking the gas-liquid experiment as an example, the entire collaborative process is clearer: Before the experiment, the operator first installs the baffle, injects the CMC solution, then calibrates the photoelectric speed compensation, and then starts the air compressor to stabilize the pressure in the buffer tank to 0.6 MPa; during the experiment, the motor drives the agitator to rotate at 200 r / min to form a composite flow, and the gas supply system injects 1.5 m³ of gas through the distributor. 3 The system generates uniform air bubbles per hour. The measurement system simultaneously collects data on rotation speed of 200 r / min, voltage of 195 V, current of 1.05 A, and viscosity of 500 mPa·s. The PLC calculates the power to be approximately 44.9 W. If any parameters are abnormal, the PLC will automatically adjust or trigger protection. After the experiment, the system automatically stores the data. The operator then turns off the equipment and exports the data, thus completing the determination of the stirring power curve.

[0026] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An experimental apparatus for detecting the characteristics of a stirring paddle, comprising a worktable (1), characterized in that: The workbench (1) is equipped with a stirring system, an air supply system, a measuring system and a control unit; The stirring system includes a stirring tank (5), a vertical plate (6), a speed-regulating motor (7), a fixed roller (8), and a stirring paddle (9). The mixing tank (5) is fixedly installed on the upper surface of the workbench (1), and the vertical plate (6) is fixedly installed on the upper surface of the workbench (1). Among them, the speed-regulating motor (7) is fixedly installed on the front surface of the workbench (1), the fixed roller (8) is fixedly installed at the output end of the speed-regulating motor (7), and the stirring paddle (9) is fixedly sleeved on the outer surface of the fixed roller (8).

2. The experimental apparatus for detecting the characteristics of a stirring paddle according to claim 1, characterized in that: The air supply system includes an air compressor (2), a buffer tank (3), and a rotor flow meter (4). The air compressor (2) is fixedly installed on the upper surface of the bottom plate of the workbench (1), and the buffer tank (3) is fixedly installed on the right surface of the vertical plate of the workbench (1). The air compressor (2) is connected to the buffer tank (3) through a connecting pipe. Among them, the rotor flow meter (4) is installed on the outer surface of the buffer tank (3).

3. The experimental apparatus for detecting the characteristics of a stirring paddle according to claim 1, characterized in that: The measurement system includes a photoelectric switch (11), an energy meter (13), a digital viscometer (14), and a temperature sensor (15). The photoelectric switch (11) is fixedly installed in the inner wall of the stirring tank (5), the energy meter (13) is fixedly installed in the inner wall of the measuring equipment housing, the digital viscometer (14) is fixedly installed in the inner wall of the measuring equipment housing, and the temperature sensor (15) is fixedly installed in the inner wall of the measuring equipment housing.

4. The experimental apparatus for detecting the characteristics of a stirring paddle according to claim 1, characterized in that: The control unit includes a PLC controller (12), which is fixedly installed on the upper surface of the workbench (1). The PLC controller (12) is electrically connected to the photoelectric switch (11), the power meter (13), the digital viscometer (14), and the temperature sensor (15).

5. The experimental apparatus for detecting the characteristics of a stirring paddle according to claim 1, characterized in that: The inner wall of the mixing tank (5) is provided with a detachable baffle (10). The detachable baffle (10) is connected to the inner wall of the mixing tank (5) through a slot. The slot is opened in the shape of a dovetail groove. The detachable baffle (10) is provided with a corresponding block.

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