Due to its high output, stable quality and suitable for scale production, the rotary tablet press has become the main equipment for tablet production and is widely used by most pharmaceutical companies. According to GMP requirements, the rotary tablet press must have a vacuum cleaner. The following discussion focuses on the causes of dust generated by rotary tablet presses, the need to increase vacuum and the comparison of common vacuum cleaners.
1 rotary tablet press works
The main working process of the rotary tablet press is continuous filling, tableting and filming.
The granular material falls into the feeder through the hopper, and is forced to fall into the middle die hole by the own weight of the material, and the upper punch and the lower punch rotate along the rail guide, and the material is pressed into pieces by the upper and lower pressing wheels, and then Undercutting the upper rail guide pushes the pressed piece out of the middle die hole and then flows into the slot.
2The reason why the rotary tablet press produces dust
The main reasons for the dust generated by the rotary tablet press are as follows:
(1) Dust generated during the manual feeding process.
(2) For the ordinary feeder, the height of the feeding hopper is not properly adjusted, so that the gap between the hopper and the grid feeder is too large, and dust is also generated when feeding.
(3) For the forced feeder, the connection pipe between the feeding hopper and the forced feeder is not tightly sealed, and dust is also generated when feeding.
(4) Dust generated by the bottom of the ordinary feeder or the gap between the scraping plate and the turntable is too large to cause powder leakage.
(5) The material flow rate and the turret rotation speed do not match the dust generated by the flash phenomenon.
(6) The ram is worn due to prolonged use, resulting in excessive clearance between the ram and the die hole in the turret, and the dust generated by the phenomenon of “puffing powder†during the tableting process.
3 rotary tablet press increases the need for vacuuming
The dust generated by the rotary tablet press is easy to cause “pluggingâ€, damage the rail guide, and cause dust to be broken in the electrical cabinet. The contaminated tablet chamber is not suitable for cleaning and disinfection in the tablet chamber. The wear of the die hole in the turntable is intensified and wasteful. In the case of materials, it is necessary to increase the dust collection device, recycle materials, improve the utilization of materials, and comply with GMP.
In the production process of the rotary tablet press, due to the feeding device or the material itself, the dust can easily fall into the middle punching disc. At the same time, the clearance between the lower punching rod and the lower middle disc is too large, and the dust will fall into the dust. The lower punching plate, so a special vacuum cleaner must be used to remove the dust.
4 comparison of vacuum cleaners
4.1 External vacuuming
At this stage, the rotary tablet press generally uses an external vacuum cleaner to vacuum, mainly divided into mechanical dust collector, wet dust collector, electrostatic precipitator, filter dust collector, but commonly used mechanical dust collector, its main structure Vacuuming through a vortex pump
The working principle of the vortex air pump: the impeller of the air pump is composed of dozens of blades, which is similar to the gas turbine impeller. When the impeller of the vortex air pump rotates, the air in the middle of the impeller blade is subjected to the centrifugal force, moving toward the edge of the impeller, and is certain The centrifugal force moves away from the edge of the impeller and enters the annular cavity of the pump body. Due to the centrifugal force and the special shape of the cavity, it acts on the air at the same time, so that the moving air returns to the impeller again, and recirculates in the same way from the starting point of the blade. movement. Since the air is uniformly accelerated, the circulating airflow generated by the rotation of the impeller causes the air to escape in a spiral trajectory. The air filtered through the filter belt is discharged into the room, which produces a slight dust in the indoor environment.
If the vortex air pump runs for a long time, the vortex motor will heat up and the pump will be easily blocked. At the same time, the powder storage barrels produced by most manufacturers are not well sealed, which makes the vacuum cleaner's vacuuming effect poor.
4.2 built-in vacuuming
The other is built-in vacuuming, the fan is placed inside the tablet machine base, the power is transmitted through the main motor, the suction port is connected to the suction nozzle, and the suction port at the top of the tableting chamber sucks the air first through the cyclone separation device. The filter element is filtered, and the discharged air flows into the tableting chamber from the annular air passage inside the base, thus forming an internal dust removing system of the rotary tablet press.
The cyclone separator of the device has the advantages of simple structure, small occupied area, convenient operation and maintenance, small pressure loss and low power consumption, and is suitable for high temperature, high pressure and corrosive gas, and the motor temperature rise is low even if the operation time is too long. Does not reduce the vacuum effect.
5 Conclusion
Through the comparison of the above dust collecting devices, the individual thinks that the rotary tablet press preferably uses built-in vacuuming to achieve a good vacuuming effect.