Filling of liquid materials (2)

3. Pressure filling method

This is a constant level filling method. As shown in Figure 9-3. The filling valve 5 is placed separately from the reservoir 8 . In addition, a liquid supply pump 7 is provided (the liquid material is fed into the filling valve via this pump and then into the container), and the connection between the container and the valve is sealed by the sealing cover 6 . The filling valve is also equipped with an overflow valve 3 . When the container is sealed, the filling valve is opened and filled, and the air in the container is discharged from the overflow tube to the reservoir. When the liquid level in the container reaches the overflow nozzle, the liquid material begins to flow through the overflow valve back to the sump. At this point, the liquid level in the container no longer changes. The relative position of the overflow nozzle and the top of the container determines the height of the liquid surface after filling. As long as the container under the filling is sealed, the liquid material will continuously flow out through the overflow tube. When the container is no longer sealed, the filling valve closes the fill and overflow ports. The liquid level in the reservoir remains unchanged by the float 4 . The liquid supply tank 1 is placed above the liquid reservoir and is connected to the liquid reservoir via the liquid supply valve 2 . The supply valve is controlled by a float.
This method is mainly used for the filling of non-foaming liquid materials and is generally limited to narrow neck containers.
4. Gravity vacuum filling method This method is a constant level filling and has the same features as the gravity filling method. Actually it is gravity filling under low vacuum (10~16Pa). This method requires that the container be sealed during filling and then fill the container with liquid material to a predetermined level. The reason for taking a low vacuum is mainly to eliminate the overflow and backflow phenomena of the pure vacuum filling method, and to avoid filling cracked bottles or notched bottles. It can also prevent drooling of liquid materials.

As shown in Figure 9-4, the reservoir is closed and located at the top. The supply pipe 1 extends from the top of the tank and is immersed in the lower part of the liquid material. The space above the liquid is maintained in a low vacuum, and the liquid level is controlled by the float 2 and maintained. At the prescribed height. The filling valve 4 is mounted below the reservoir. When the container is conveyed under the valve, the lifting mechanism lifts it up, conforms to the sealing cap 5, seals the container, and continues to rise to open the valve. As the container is gravity fed into the container via the sleeve in the valve. As with gravity filling, the liquid level in the vessel no longer rises when the vent is closed by the rising liquid material. After the filling is completed, the container is lowered and the filling valve is automatically closed by a spring.
This filling system is especially suitable for the filling of white wines and wines, because the degree of turbulence generated during the filling process is low and the volatilization of volatile gases in the wine is minimized, without changing the alcohol concentration. When filling fine wines, it does not lose mellow. In addition, this filling method can also be filled with toxic liquid materials (such as pesticides, etc.).
5. The pressure gravity filling method is a liquid level filling and is limited to the filling of CO2-containing beverages such as soft drinks, beer and champagne. The principle is to flow into the container by the gravity of the liquid material itself. The gravity vacuum method mentioned above is based on gravity filling under negative pressure, and this method is based on gravity under positive pressure. The purpose of pressurization is to keep the CO2 content in the liquid constant. The pressure is preferably 1 to 9 kg/cm2. However, this pressure is not used to enter liquid material into containers. As shown in Figure 9-5, the reservoir is sealed and placed above the turntable. Its liquid level is controlled by the float 1, and the space above the liquid level is filled with compressed air or CO2 to maintain a certain pressure (required when filling beer). CO2, to avoid contact of beer with oxygen, to control its oxygen content to ensure quality). The liquid material enters through the lower supply port 2 . The filling valve 4 is installed in the reservoir, and an exhaust pipe is arranged in the middle part of the filling valve. The top of the exhaust pipe protrudes from the liquid surface, and an inflation valve 6 is arranged, and the exhaust port 7 and the pressure relief port 5 are arranged at the lower end. When the container is raised to the filling valve opening, the container is closed by the sealing cap 3, then the spring is compressed, the filling valve is opened, and the filling is started. At the same time, the mechanical key opens the inflation valve on the top of the exhaust pipe so that the pressure in the vessel is equal to the pressure in the upper part of the reservoir, and is usually “isobaric”. When the liquid rises in the exhaust nozzle, the level no longer changes. In the case of long-spill-bottom lift-type filling, during the filling process, the speed of the exhaust gas can be changed so as to change the filling speed and slow down first and then quickly. The air in the container during filling is discharged into the reservoir through the exhaust pipe. When the liquid material is filled to the specified liquid level, the air at the top of the container has a certain pressure. To eliminate this pressure, install a mechanical pressure relief vent in the valve so that the pressure at the top of the container is the same as the atmospheric pressure. When the container is lowered and the seal is lost The liquid material will not be ejected.

6. Liquid Level Filling Method This method is a fixed level filling. It is usually used for the filling of narrow neck plastic bottles and glass bottles. Its feature is that the container does not need to be sealed when filling, so it is especially suitable for pressure resistance. Small plastic bottles, this is a relatively new filling method. As shown in Fig. 9-6, the liquid reservoir is sealed. The liquid material enters from the liquid supply port 6, and the liquid level is controlled by the float 5, and the upper part of the liquid maintains a certain pressure (0-15 Pa). The liquid flows into the container through the inlet pipe 2 and the filling valve 8 under pressure. Because the container mouth is not sealed, the air in the container is discharged from the inlet pipe when the liquid material is poured.

The flow of liquid material is controlled by a pneumatic controller consisting of a differential pressure or low pressure fluid device. The controller is mainly to detect whether the container is in place and to open and close the filling valve between the liquid reservoir and the inlet tube according to an appropriate signal. When the container is in place, the controller starts and filling begins. An air sensor tube is installed in the liquid inlet tube. During the filling process, low pressure (5-25 Pa) air flows into the container through the air sensor tube. When the liquid level rises to the sensor tube mouth, the sensor air flow stops, the air pressure in the sensor tube increases, the controller closes the filling valve through the role of the sensitive interface valve, the filling stops, and the liquid level remains constant.
The design of the inlet pipe should be able to accurately control the flow of liquid material into the container and make it flow along the inner wall of the container to ensure non-turbulent state, so that the liquid material can be reduced in contact with the air. After the screen is filled in the inlet pipe, high foaming liquid material can be filled. The filling speed of this method is much faster than that of gravity filling and vacuum filling, and the liquid level accuracy is very high. It is an ideal method for high-speed filling of plastic bottles.
(To be continued)