Safety Features In RMG

RMG is a rapid mixing granulator which is used for wet granulation during tablet manufacturing in pharmaceutical industries.It is a very high speed equipment & various safety features must be installed in RMG for the safety & protection of operator, product & equipment itself.

In this article we will discuss some key safety features which must be installed in RMG & you must highlight these safety features while generating URS or user requirement specifications

  • Air Purging System
  • Overloading Sensors
  • Lid Sensors
  • Alignment Sensor

Air Purging System

A Compressed air purging system is installed in RMG where a continuous stream of compressed air is coming out along the shaft of impeller blades & chopper blades.This compressed air purging always remains ON as soon as we turn RMG ON, either for processing or washing.


The purpose of this purging air system is to prevent the entry of powder particles into the shafts of impeller & chopper blades motors during the batch processing & to prevent the entry of water during the washing process.


The equipment life is increased & chances of cross contamination are also prevented.

Overloading Sensors

Overloading sensors are installed in RMG to indicate that the load on a specific rotational component of the rapid mixing equipment is higher than the recommended values.This overloading signal is displayed on the HMI and a specific alarm system beeps to indicate that do not proceed further otherwise the overload on motor may result in its damage.


To understand the concept of overloading sensors in RMG let’s discuss it on the basis of real time explanation.

In RMG there are three motors installed which bear the load & these are

  • Impeller Motor
  • Chopper Motor
  • Wet Mill Motor

Impeller motor

During the process of kneading, when we add binder solution over the powders the load is increased on the motor which is rotating the impeller blades to mix the binder solution with powders.

If this load is increased than the recommended values the over load sensors immediately send signals to the PLC & display it over the HMI.Alarm system is activated to convey the alert,  stop the mixing process otherwise the motor may burn out.

Chopper Motor 

In the same way the chopper motor is used to rotate the chopper blades to break the large lumps & if the lumps formed are very large creating hindrance for blades to rotate it sends the same overload signals to HMI as in case of impeller motor.

Wet Mill Motor

When the kneading process is completed the wet mass is delivered to the wet mill to reduce its size & the motor of the wet mill is also sensitive to the load.If the wet mill motor is overloaded during wet sieving the sensors installed along it will send signals to HMI through PLC and alarm will ring.


The cost of motors installed in RMG is very high & their smooth running is very important to achieve the set production targets so these types of overloading sensors in RMG prevent motor damage & breakdowns.

Lid Sensors

As the name indicates this safety feature monitors the status of the lid in a rapid mixing granulator.

Two lids are installed in a rapid mixing granulator.One is over the main mixing bowl of RMG & other is over the wet mill.

The function of these sensors is to sense the opening & closing status of these lids & if these lids are open the mixing process in the main mixing bowl will not start & in the same manner if the lid of the wet mill is open this sensor will not allow the wet mill to start.


We know that the blades speed is very high & if any operator inserts their hand in the mixing bowl or wet mill chamber by opening its lid it may result in a serious accident.So these sensors ensure operator safety.

Alignment Sensor

Alignment sensor senses the position of the wet mill & if the wet mill is not at its place it will not start the working of the wet mill.


If the wet mill is not at its place the product spillage may occur so this sensor ensures product safety.

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