SOP for Operation and Cleaning of Fluidized Bed Dryer

To provide a procedure for the operation and cleaning of FBD (Fluidized Bed Dryer). 

It is applicable to the operation and cleaning of FBD located in the Production area. 

Operator: To operate and clean the equipment as per this procedure. 
Supervisor: To ensure that the SOP is followed. 


  • Ensure the cleanliness of FBD and the area. 
  • Mount the filter bag on Bag hanger and bring it to working position by Pneumatic hand lever valve for filter bag ‘up’ and ‘down’ position at clamp provided for the purpose. 
  • Lock filter bag by supplying compressed air at inflatable seal for filter bag sealing. 
  • Load the product to be dried in the product container mounted on the trolley. Run in the trolley along with loaded product container and position it in line with the main body. Lift the loaded product container to the FBD by using on/off valve at the control panel till the Product container top face is stopped by sealing gasket of main body. 
  • Set the Dry air temperature by temperature controller at the control panel as stipulated in the BMR.  
  • Ensure that spring loaded earthing probe is in contact with the product container with spring pressure before switching on the motor. (The connection of earthing should be positive and shall be checked from time to time. Ensure that main body and product container are connected to the earthing terminals before each operation). 
  • Check and set the compressed air line pressure at 4 bars in the main line. 
  • Switch on the Mains supply. 
  • Set the Cycle timing by Timer at control panel as stipulated in BMR or as per the product requirement. 
  • Switch on the Exhaust blower. 
  • Open the inlet and exhaust dampers to start fluidization. The material being fluidized can be observed through the sight glass window. If the granular mass is sluggish or does not move when the air damper is opened, the damper must be moved between open and close position several times until the material slides along walls of container. Ensure inlet and exhaust damper is fully open. 
  • The filter bags will be shaken out at scheduled time duration through Pneumatic solenoid valve. During shaking operation keep inlet damper at close position. This will ensure effective shaking at Filter bags. 
  • As per the set cycle time, FBD will switch off automatically. 
  • Switch off the Mains.  
  • Shake the finger bag well connected with the pneumatic solenoid valve. 
  • Operate the hand lever at the control panel to release pressure, so that the product container is released and the trolley can be moved. 
  • Run out the trolley along with the product container. 
  • Unload the product from the product container by manual tilting arrangement provided for the purpose. 
  • To prevent accumulation of heat, the blower should be allowed to run for a certain period of time after the heating has been stopped. 
  • Record the details of operation in the Equipment usage log-book. 

Partial Cleaning
  • At the beginning of every shift operation wipe FBD bowl, retarding chamber and other utensils with dry lint free cloth. 
  • At the end of shift operation wipe FBD bowl, retarding chamber and other utensils with dry lint free cloth.

  • Switch off the main power supply. 
  • Close the compressed air valve. 
  • Dismantle the FBD bag and clean as per SOP  ‘Cleaning and storage of FBD bags and Sieving bags’. 
  • Dismantle the product container sieves. Clean the sieves to ensure trouble free fluidization.  
  • Clean the product container, main body and rinse with potable water. Apply 1% soap solution if required to clean the machine parts. Finally rinse with purified water. 
  • Dismantle the air filters and clean as follows at least once in a week: 
  • Remove the filter, place it in a clean poly bag and affix the label ‘To be cleaned’. 
  • Transfer the filter to the cleaning area. 
  • De-dust the filter with vacuum cleaner. Suction must be in the same direction to the actual flow direction. 
  • Pass the compressed air through the filter in the opposite direction to the actual flow direction. 
  • Pass the compressed air through the filter in the opposite direction to the actual flow direction. 
  • Clean the filter with raw water by passing the water through the filter in the opposite direction to the actual flow direction. 
  • Clean the filter with 0.1% detergent solution, if required. 
  • If detergent solution is used, again clean the filter with water till the filter is free from froth.  
  • Finally, clean the filter with Purified water. 
  • Allow the filter to air dry. 
  • Cover the cleaned and dried filter in a separate clean poly bag and affix the label ‘Cleaned’. 
  • Take the filter to FBD for re-fixing. 

Cleaning of finger bag
The cleaning of the finger bag should be done cautiously dedust the individual finger chamber of the finger bag. Keep it in a polythene bag and send it for laundering to the linen Deptt.
  • Cleaning of retarding chamber, trolley, and bowl – Take retarding chamber along with trolley and bowl to the washing area. Wash out the Retarding chamber and trolley with hot water and scrub both of them with a clean nylon scrubber. After washing with hot water then wash both of them with 0.1% v/v solution of Teepol, then rinse retarding chamber and trolley thoroughly with hot water and followed by D.M. Water. If the powder is found stuck then use steam to remove the powder.
  • Confirming the effectiveness of cleaning – The DM Water rinse of retarding chamber and bowl is sent for testing to the quality control laboratory to ensure the absence of the previous product’s traces.
  • Assembling – Fix the laundered finger bag in a metallic hanger around the retarding chamber. Clamp the retarding chamber on the body with the fixed bolts. Lift the bottom of FBD. And seal the trolley with a bowl to the retarding chamber.
  • Fix the ‘Cleaned Slip’ Label.

Frequency of cleaning: 
  • Clean the machine as mentioned in steps after every product change over and after three consecutive batches of the same product. 
  • Record the details of cleaning in the Equipment usage log-book. 

Equipment Holding Time After Cleaning
  • Plastic Poly shall be used to cover FBD bowel, Retarding chamber mouth, FBD bags till the next batch is commenced.
  • The dryer must retain covered until the next batch is ready.
  • After cleaning, if dryer is not used within 72 hours, repeat the partial cleaning procedure before use.

SOP: Standard Operating Procedure. 
FBD: Fluidized Bed Dryer. 


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