When the liquid Filling machine starts to fill, the filling control loop adopts cascade proportional double cross-limit control. There is a deviation signal between the outlet weight of the material and the set value. The main regulator operates in the reverse mode. One of its output signals is sent to the high-value selector for judgment and comparison with the liquid flow signal. The output of the high-value selector is multiplied by the gun liquid ratio coefficient and sent to the gun volume regulator as the set value. At the same time, the other output signal of the main regulator is sent to the low-value selector for judgment and comparison with the Electronic scale gun volume signal. The output of the low-value selector is used as the set value for the liquid flow regulator. The main regulator outputs the deviation signal of the material weight through the high-low value selector to control the liquid regulator and the gun volume regulator, and actuate the regulating valve to meet the needs of the material filling changes. 

The automatic filling machine is a straight-flowing, continuous liquid filling equipment. It is driven by a motor, featuring a flat conveyor belt and a pair of barrel-feeding screws driven by a servo motor. These components separate the barrels and synchronously send them into the barrel feeding star wheel. The barrel feeding star wheel is driven by the sealing part through a chain and sends the empty barrels to the weighing plate under the filling machine. Once the position is detected, filling begins. After filling is completed, it enters the sealing area, where the inner cover is placed, the inner cover is sealed, and the outer cover is pressed. Finally, the sealed ones pass the sealing inspection and enter the next stage, while those that fail the inspection go to the bucket rejection area. When the empty barrels pass through the electronic scale filling nozzle for rough filling and then undergo precise filling by the filling nozzle, they are transported by the conveyor belt to the next process. Place the empty barrels on the automatic liquid filling conveying chain, and the pusher pushes the empty barrels to the filling weighing line and filling station. After the bucket delay reaches the point, the weight value of the empty barrel is collected for automatic skin removal, and then the filling head is opened to start large-flow rapid pre-filling. When the pre-filling volume is reached, the empty barrel enters the electronic scale filling nozzle for rough filling again. The filling volume is determined by the length of the electronic scale filling time of the filling nozzle. After the filling is completed to the preset value of the coarse valve, it enters the small-flow slow filling stage, and when it reaches the preset value of the fine valve, the filling head is completely closed. After the filling is completed, the filling weight line is restarted, and the automatic filling weight line drives the heavy barrel to the next process. Thus, the filling weight work is completed. 

The Filling system transports the empty barrels to the filling position, aligns the barrel opening and the spray gun opening, and presses the "start" button. The spray gun is driven by the cylinder and enters the barrel; when the spray gun is detected to be in place, the bottom valve opens, and the nitrogen supply valve starts to inject dry nitrogen through the filling port into the barrel, replacing the air inside the barrel with nitrogen, which accelerates the drying of the barrel inner wall and ensures the safety of filling. During nitrogen filling, it is necessary to ensure that the air in the container is replaced. The specific amount of nitrogen filling can be adjusted by the control instrument. After a certain amount of nitrogen is filled, the nitrogen supply valve is closed, and the control instrument automatically removes the empty barrel's skin weight from the scale, then both the fast and slow feeding ball valves are opened simultaneously; first, the material is added quickly, and the spray gun stays at a very low position for a period of time before starting to rise below the liquid level for filling; at the middle point, it stays for three times as the liquid level rises, then stops at the barrel opening, and then adds material slowly; when the filling volume reaches the preset advance volume, the ball valve and the bottom valve are closed; the spray gun rises outside the barrel; the vacuum suction device is activated to ensure no residual liquid droplets leak. All the sealing parts of the pipeline are sealed with polytetrafluoroethylene material to meet the no-leakage requirements. After the material filling and filling are completed, the full barrel is automatically pushed to the real barrel roller path, and the automatic pneumatic cap screwing is carried out; the capped real barrel is pushed to the bucket unloading buffer position. 

After pressing the automatic filling start button on the control panel of the weighing filling machine, the PLC automatically executes the filling program, opens the gun valve, and starts the pump motor. After the motor starts, it opens the gun valve to the maximum opening degree for large-volume filling. During the weighing process of the electronic scale, the tare weight is automatically deducted. Then, the control valve is opened, and the material is quickly fed into the weighing hopper from the storage bin. When the preset value is reached, the control door is closed, and the rapid feeding mode is changed to a slow feeding mode. When the material quantity reaches the drop value, the control door is closed, and the filling process is completed. After stabilization, the PLC sends data and keeps the signal to the weighing instrument. The weighing instrument automatically compares with the set underfill, overfill, and upper limit values. If it is an appropriate amount, the "filled properly" light is on; if it is overfill or underfill, the "out of tolerance" light is on and an alarm is triggered. When there is a shortage, it is allowed to replenish by pressing the "slow feeding" button and automatically reaching the appropriate amount. After the filling is completed, the gun valve closes the filling opening degree, the electronic scale monitor is connected and interlocked, and if the electronic scale weight is detected, the next step is continued; when the filling target quantity of the electronic scale is detected, the filling gun is closed, the electromagnetic valve of the pump motor is closed, and the circulation switch enters the normal operation state.