Solutions for Unstable Filling Volume of Filling Machine
Solutions for Unstable Filling Volume of Filling Machine
Solutions for Unstable Filling Volume of Filling Machine
October 31, 2022

Reasons and solutions for unstable filling volume of filling machine

Filling accuracy is the first element to express the performance of the filling machine, which directly affects the quality of medicines. The stability of filling accuracy is an important guarantee for the production of qualified medicines. Aiming at the phenomenon of unstable filling volume in the ceramic pump filling system of the filling and stoppering machine, the reasons can be analyzed from two aspects of mechanical structure and electrical control, and proposing the solutions.

1. Reasons Analysis

(1)The mechanical structure is shown in the figure

The mechanical structure of the filling system is as follows:

1. Liquid distribution system: It is used to transfer the prepared liquid medicine to the dispenser or liquid medicine bag.

2. Dispenser: a buffer-dispensing integrated tank and a closed dispenser. The following table shows the configuration methods of the commonly used dosing system.

Liquid Storage Tank
Buffer Dispensing Integrated Tank
Closed Dispenser
Liquid Medicine Bag

Note: Y means yes, N means no.

3. The filling part is mainly composed of rotary valve motor and driving unit, multiple sets of filling motor and driving unit, transmission gear, roller screw and ceramic pump.

4. Needle frame structure: used to track and locate the bottle for corresponding filling.

(2) Electrical control

Filling is carried out by the absolute position control mode of the servo motor, which can be precisely positioned. When the servo motor does not reach the specified position, the servo motor will alarm and stop the filling action and equipment. At the same time, the control of the rotary valve is the same as the control of the filling pump. There is also the control of the reciprocating and lifting of the needle holder. The above three points are all electrical control.

2. Solutions

From the above, the inaccurate filling volume is generally caused by dripping or bubbles, and the main reasons for dripping and bubbles and the solutions are as follows:

(1)The sterilizer does not choose non-metallic materials. During sterilization, the pump rod is in contact with the metal material, and the pump rod is adhered to the metal material, which is easy to cause the pump rod to wear, resulting in poor air tightness and air bubbles during the filling process.
Solution: try to use special sterilization equipment.

(2)When the pump is installed, the pump body and the pump rod are mixed, and the gap of the pump does not match, which is easy to cause the pump rod to wear, and the air tightness is poor, and air bubbles appear during the filling process.
Solution: The pump body and the pump rod are marked, not mixed.

(3)The installation position of the liquid storage tank, the liquid dispenser, the ceramic pump and the needle holder. The height difference between the installation position of the buffer tank and the installation position of the ceramic pump is too large, and the pressure of the ceramic pump is too large, which may easily lead to dripping of the filling needle.
Solution: Minimize the height difference between the installation positions of each component. If it cannot be reduced, add a buffer device between the buffer tank and the pump.

(4)If the connection between the silicone tube, the dispenser and the ceramic pump is not tightened, air bubbles or drips will occur;
Solution: add a check before each boot, if the above situation occurs, replace the connector or silicone tube immediately.

(5)The connection between the ceramic pump and the rotary valve is too shaken or the verticality of the pump is problematic, resulting in dripping;
Solution: Increase the number of tests after each installation of the pump. If the connection slip knot is too shaken, please replacing it.

(6)The rigidity of the filling servo motor itself is insufficient, resulting in slight shaking of the ceramic pump in the later stage of filling, resulting in dripping.
Solution: Manually adjust the rigidity of the servo motor until it is suitable.

(7)The filling speed is too fast, resulting in excessive pressure on the silicone tube, resulting in dripping.
Solution: You can reduce the filling speed, change the acceleration and deceleration of the filling pump, or replace the wall thickness of the silicone tube.

(8)The length of the needle holder and silicone tube is too long, resulting in excessive shaking and dripping.
Solution: Tighten the needle holder. If it cannot be fastened, replace the fastener. Reduce the length of the silicone tube as much as possible. If there is still shaking, add a fastener in the middle.

(9)Due to the excessive setting of the suction volume, the liquid medicine will return to the silicone tube, and bubbles will easily be generated at the needle mouth when the next filling is performed, thus affecting the filling volume (mainly small-sized products).
Solution: According to different pharmaceutical processes, add different formulas for suction volume, and call different formulas for suction volume under different circumstances.
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