Most of the packaging of liquid products is realized by filling machines. According to the characteristics of liquid products, it is necessary to use large-capacity, high-precision automatic filling machine for packaging. For this reason, the technicians have specially developed a large-capacity, high-precision liquid filling machine to meet the needs of the enterprise's production.

1 Filling design

Filling composition

According to the specifications of the enterprise's products, the automatic filling machine consists of 3 kinds of independent automatic filling machines, capping machine, conveyor, baler and filling equipment for 30kg barrels, 250kg/1200kg barrels.

2Technical Parameters

Material characteristics: liquid, acid, density 1.2 ~ 1.3g/cm2;

Viscosity: 0.5～1.5Pas;

Ambient temperature: 5～35℃;

Filling capacity: 30kg;

Drum type: ≥100kg/min; 250kg;

Drum type: ≥140kg/min; 1200kg;

Drum type: ≥200kg/min;

Filling precision: 30kg;

Average error of barrel type (sampling): ≤±38g; 250kg;

Average error of barrel type (sampling): ≤±318g; 1200kg;

Average error of barrel type (sampling): ≤±1500g;

Measurement control: adopt mass flow meter to control the filling speed to ensure the required filling precision;

Maximum speed of conveyor: 12m/min;

Capping speed: 6～15 buckets/min;

Filling material: relevant parts comply with European food safety standards.

3 Filling process characteristics

Each filling line is completed by its own filling head, and each filling head is equipped with its own measuring device to ensure the accuracy of the filling quality.

There are 3 groups of filling points on the whole filling line, which can complete the filling of 3 different products (materials) respectively (only 1 product is filled during production). The filling machine on each filling point is equipped with 3 filling heads, which can independently complete the filling and metering of 3 buckets at the same time. When working, the empty barrels are put into the conveyor, transported to the filling position, positioned and locked by the relevant institutions, and then the filling head is automatically lowered and inserted into the mouth of the barrel after all the empty barrels are detected in place by the detecting device. The flow control valve and filling valve will be opened at the same time, and the material will be filled through the flow meter, flow control valve (fully open) and filling valve, and the flow meter will start to measure at the same time. When the filling reaches the set value (a certain percentage of the filling volume), the flow control valve receives a signal, the opening becomes smaller, and the flow of material through the flow control valve decreases until the completion of the accurate filling volume. After the filling is completed the flow meter sends out a signal, the flow control valve, filling valve at the same time quickly closed. Then the filling head lifts up and opens the locking and positioning device to complete the filling.

After filling, the product is transported to the capping station by conveyor to complete the capping process. After the capping is completed, the barrels are sent to the designated position by the conveyor, and the pneumatic pusher pushes the barrels into the labeling station to complete the labeling process. Finally, the barrels are put into the pallet on the roller conveyor by hand for palletizing, and after palletizing, the barrels are sent into the winding machine together with the pallet to complete the winding and packaging.

4 Development of filling machine

Weighing filling machine has a simple structure, high reliability, accurate measurement characteristics. Among them, the filling head is the key component, and the filling valve diameter corresponding to different barrel types is different. After filling, to prevent the material remaining on the surface of the filling head to cause pollution of the surface of the packaging container and the environment of the packaging place, it is required not to drip. The filling head has a special design in structure, the head surface is smooth cone surface, which is convenient for the residual liquid to be concentrated in the top of the cone after filling, and then the residual liquid will be sucked into the residual liquid collector through the small holes in the top of the cone, to ensure that there is no dripping after filling. The material to be filled is food grade, in order to prevent the material from being contaminated, all the actions of the filling head are pneumatically controlled, and its parts and seals are selected according to food grade.

The filling head must accurately complete the rising, descending, opening and closing actions during the filling work. Rising and falling are controlled by the main cylinder; opening and closing are controlled by the flow meter signal. Filling when the main cylinder on the filling machine down, filling valve inserted into the barrel mouth, filling valve on the small cylinder to launch and open the valve mouth, the material through the flow meter, filling valve will be injected into the barrel, at the same time, start real-time collection of signals issued by the flow meter (counting). After the barrel is full of polymerized ferric sulfate weighing and filling machine closes the valves before and after the flowmeter, the small cylinder on the filling head retracts to close the filling valve, the residual liquid recycling starts to work, the residual liquid on the head of the filling valve is recovered to the residual liquid recycler by the vacuum, at the same time, the main cylinder on the filling machine lifts up, the positioning locking device opens, and the barrel is moved out by the conveyor, the end of the filling.

5 Filling Control

Characteristics of filling control

It integrates computer technology, programmable control technology, data setting and display technology, high-speed counting technology (5 channels/module, 100kHz), etc. The hardware and software are reasonably configured. The weighing and filling machine has a high degree of automation, simple structure, low failure rate and easy operation and maintenance. All parameters meet the design requirements, including the filling accuracy control within ± 0.1%, higher than the user's requirements.

Main functions of filling control

Through the software programming to realize the flow signal acquisition, the PLC conversion, calculation, and grading control pipeline valve opening, closing, so as to achieve the filling accuracy control; the use of photoelectric position recognition function to control the positioning of the filling container and locking mechanism of the opening, closing, to achieve automatic positioning, automatic start-stop as well as no bucket without filling control function; material category selection and setting, the weighing filling machine automatically adjust and set the corresponding parameters manually, and the filling accuracy control. After the material category is selected and set, the weighing and filling machine automatically adjusts and sets the parameters for manual/automatic conversion. Automatic control is divided into automatic control of single machine and overall control of production line. In the automatic state between the single machine can realize the interconnection of interlocking, and in the single machine needs to debugging, maintenance or in case of failure and can be converted to manual operation state.

6 Conclusion

Large-capacity high-precision full-boost oil automatic liquid filling machine applies microprocessor control technology to manage process parameters, convenient and reliable automation of the production process. The application of PC on the filling machine and the key real-time monitoring, the use of foreign advanced main controller and configuration of high-speed counting module to collect the flowmeter signal; monitoring the instantaneous flow of materials in the pipeline, and can be over the limit of the flow alarm and display; the application of control technology so that the mechanical structure has been simplified, and the operation of the adjustment is also more convenient and quick.