Spiral quantitative feeder, also known as spiral feeder or rotary conveyor, is a commonly used continuous feeding equipment, widely used in industries such as chemical, building materials, grain, metallurgy, etc. It is used to continuously and uniformly transport powdered, granular or small block materials from one position to another, and achieve quantitative feeding during the conveying process.
Controlling the speed and conveying capacity of the spiral quantitative feeder is a key step in achieving precise feeding. Here are some commonly used control methods:
1、 Control the rotational speed
1. Variable frequency speed regulation
♦ Principle: Using a frequency converter to change the power supply frequency of the motor, thereby achieving stepless adjustment of the motor speed. The frequency converter can receive control signals, adjust the output voltage and frequency according to the magnitude of the signals, and thereby control the speed of the motor.
♦ Implementation: Introduce a frequency converter into the motor drive system of the spiral quantitative feeder, and control the motor speed through the frequency converter. The control system (such as PLC or microcontroller) sends control signals to the frequency converter, and the frequency converter adjusts the motor speed according to the signals, thereby achieving the speed adjustment of the screw shaft.
♦ Advantages: Wide speed range, high precision, good stability, and the ability to achieve soft start and soft stop of the motor, reducing the impact on the power grid and equipment.
2. Mechanical speed regulation
♦ In some simple application scenarios, the speed of the motor can also be adjusted by changing the diameter of the motor pulley or adjusting the transmission ratio, thereby adjusting the speed of the screw shaft. But this method has limited adjustment range and low adjustment accuracy.
2、 Control the conveying volume
1. Speed control method
♦ Due to the fact that the conveying capacity of the spiral quantitative feeder is proportional to its rotational speed, the conveying capacity can be directly controlled by adjusting the rotational speed. When it is necessary to increase the conveying capacity, the rotational speed of the spiral shaft can be increased; Conversely, reduce the rotational speed.
2. Spiral diameter adjustment
♦ Although direct adjustment of the spiral diameter is not common in conventional spiral feeders, in some specially designed feeders, the conveying capacity of materials may be affected by changing the diameter of the spiral blades. When the diameter of the spiral increases, the conveying capacity of the material will also increase accordingly; otherwise, it will decrease. But this method requires more complex mechanical structures and control systems, and the adjustment accuracy may be limited to some extent.
3. Feed inlet control
♦ Control the amount of material entering the hopper by adjusting the size of the feed port or installing a flow control valve. This method can affect the conveying capacity to some extent, but it is usually used as an auxiliary means combined with speed control to achieve more accurate quantitative feeding. In practical applications, comprehensive control is usually used to achieve precise quantitative feeding by combining multiple control methods. For example, frequency conversion speed regulation is the main method, supplemented by feed inlet control or spiral diameter adjustment (if applicable), and flexible adjustments are made according to the actual situation of the production site.
Precautions
♦ When controlling the speed and conveying capacity, it is necessary to ensure the stable operation of the spiral quantitative feeder and avoid the occurrence of overload or underload.
♦ Regularly inspect and maintain equipment to ensure the normal operation and good sealing performance of each component.
♦ Reasonably set control parameters according to production needs to achieve the best feeding effect.