At present, the cement packaging of many small cement enterprises in many places is mostly measured by simple double-mouth packaging machine and using a platform scale. The deviation of bag weight is large, the qualification rate is low, the labor intensity of workers is large, and the output at the time of Taiwan is also very low. The automatic metering control circuit designed in this paper makes a simple modification of the simple double-mouth packaging machine, which can achieve packaging and metering automation, improve the bag weight pass rate and the Taiwan time production, and the transformation investment cost only needs several hundred yuan.
The simple double-mouth packaging machine controls the swinging material valve through the handle, so that the No. 1 nozzle and the No. 2 nozzle wheel are discharged. After the transformation, the handle is actuated by the traction electromagnet, and the metering reed switch and the control circuit mounted on the scale arm realize the automatic metering conversion of the No. 1 nozzle and the No. 2 nozzle.
The working process is shown in Figure 1.

figure 1

First, the scale 砣 is pre-adjusted to the bag quantitative position. When the line is connected, if the electromagnet mQ1 is first sucked, the handle is pulled to close the No. 2 mouth of the material valve, and the No. 1 mouth is opened to measure the cement package. When the weight of the bag reaches the required level (such as 50 kg), the magnet is mounted on the scale to make the reed switch pull-in. Through the control circuit, the electromagnet mQ1 is de-energized and the mQ2 is electrically connected. The handle closes the No. 1 mouth of the material valve, opens the No. 2 mouth for cement packaging measurement, and the cement packaged in No. 1 mouth can be unpacked (the reed switch is disconnected after unpacking, and the working state of the circuit is not changed). When the cement bag packed in the No. 2 mouth reaches the required level, the reed switch is turned on for the second time, the control circuit is turned over, and the above process is repeated. This cycle reciprocates to achieve automated metering and metering. Throughout the process, the operator simply inserts the bag, unpacks and periodically calibrates the scale. If the counter and the unpacking mechanism are installed, the whole process of packaging, metering, production accumulation and unpacking can be automated. After the transformation, the control accuracy can reach ±0.4 kg, and the bag weight pass rate is 95%. Appropriate transformation of the transmission device to increase the speed of the packaging machine can increase the production time.

figure 2


Automatic metering control circuit, as shown in Figure 2.
BG1 and BG5 and J1 and J2 form two electronic switches. BG2 and reed switch form a trigger signal circuit. Each time the reed switch is turned on, an electric signal is generated, and C3 is added to the bistable circuit composed of BG3 and BG4. Input. This bistable circuit can control the direction in which the trigger signal is introduced so that it is applied to the base of the conducting tube each time without being applied to the base of the cut-off tube. Assume that BG3 is off and BG4 is saturated. At this time, the base of BG1 is turned on by R6 and R1 to obtain a forward bias voltage. Relay J1 pulls in and drives electromagnet mQ1 to work. The collector and base potential of BG4 tube are close to zero. When the trigger signal is added, the diode D8 is turned on, so that the circuit is quickly flipped to BG3 saturation, and BG4 is turned off. At this time, the base of the BG5 is forward-biased through R7 and R11, and the relay J2 is attracted to drive the electromagnet mQ2. Working, BG1 base is cut off due to reverse bias, J1 is released, mQ1 is not working, so every time the reed switch is turned on, the circuit is flipped once, and the electromagnets mQ1 and mQ2 are switched once.