Feeding and blending

Question 1

what is the idea continuous feeding and blending units?

Answer 1

is to replaced the IBC with the feeding and blending unit (FBU)

Question 2

what is the advantages of the continuous blender?

Answer 2

ensures the homogenity of the powder blend

Question 3

what are general strenghs of continuous processing?

Answer 3

easy to integrate into an existing continuous process
Small footprint (less GMP space)
Less risk of demixing due to small volume, less itermediate tanks
No scale up
cuts off of operating costs
improved product quality (homogeneous shear rate and limite RTD)

Question 4

which feeder system do we have?

Answer 4

Volumetric and gravimetric feeding

Question 5

what is the main difference volumetric and gravimetric feeding

Answer 5

the screw speed is constanst in the volumertic feeding, whereas in the gravimetric feeding the the screw speed is based on the loss of weight

Question 6

What makes volumetric feeder difficult?

Answer 6

it changes the density at a constanst feeding. e..g Amore fedd the feeder is, the higher the bulk density which chould leads to bad zone. Also agglomeration.

Question 7

what can be done in a case of a agglomeration?

Answer 7

inregtration of a cone mill

Question 8

What

makes proper volumetric feeding challenging

Answer 8

Distrurbances resultsing in unequal material flow (feed rate vairation)
-Fill level can have an impact on bulk density
Natrual variation of product bulk density
Formation of dead zones, bridging, agglomeration, which leads to non-uniform filling of feeding too requires more control

Question 9

What should be used instead of the volumetric feeding?

Answer 9

Gravimetric or Loss in Weight Feeding

Question 10

How

does a Loss In Weight Feeder work

Answer 10

1. Setpoint by the formulation
2. control unit which set the rpm of the LWF
3. the Load cell measures the loss of weight of the feeder
4. the control can calculate how much material is being feeding
5. Increase of the rmp of te screws, if the setpoint is not reached
6. Aim is to maintain the constant flow of the material at the outled of the material

Question 11

What happened if the fill run empty

Answer 11

1. in refill one should be in the steady state as long as possible
2. Refill of the feeder, we have the increase of weight, weight signal can not be used during the refill process, therefore we switch shortly to the volumetric mood (plus settling time)

Question 12

what is the NAMUR Na 40 used for?

Answer 12

to measure feeder accuracy independently

both refill method and head affect are considered during the test

Question 13

how is the dosing accuracy in the N 40 defined?

Answer 13

as the deviation of the mean value from the nominal value

Question 14

how is the assessment of the performance of the LWF?

Answer 14

it has to be accuracy, by using the NAMUR which meaasures the the consistancy of the feeder flow around the setpoints

Question 15

whih type of mixing principle do we have?

Answer 15

radial and axial mixing

Question 16

radial mixing?

Answer 16

homogeneous bledn particles with each other

Question 17

axial mixing?

Answer 17

continuous mixing, detect the variation, bulk density changes

Question 18

How is fluctaution damp out?

Answer 18

by the RTD of the blender

Question 19

what happend of the RDT is increased?

Answer 19

the bigger the RDT, the better the demp effect of the belnder and still obatin a good quality

Question 20

to obtained the long RDT, the speed has to be lower. what is the conquencey of that?

Answer 20

it leads to an increase of the radial mixing , which affects the axial mixing. it’s reduces the variance reduction ratio

Question 21

what is the disavantages of the a higher RDT?

Answer 21

the better the blending process will be. But it aslo leads to increase of the blender size,affecting the start up phase (genra out of steck material)

Question 22

what does steady state means?

Answer 22

the input through the feeder equal the outcome of the blender. When the input and output is constanst, the mass of the blender is constanst

Question 23

how does a particle behaves inside a continuous blender?

Answer 23

each particle moves at a different speed through the blender–> probabality density function

Question 24

on what does the speed of the particle depends?

Answer 24

on particle characteristics (shape, size, density, van der waals etc)

Question 25

what happend if the one has difference powder characteristics?

Answer 25

if their speed is different through the blender, it can have an impact on startup but also material traceability

Question 26

what is at the SS?

Answer 26

the speed of the partciles does differ anymore

Question 27

how can the SS be reached quickly?

Answer 27

by using a smaller blender

Question 28

what are some challenges of CM?

Answer 28

equipemt complexity
complex formulation (too many ingredients, it's not possible to arrange so many feeders around one blender

Question 29

what are the challenges in low through put rates?

Answer 29

limitation of numbers of loss in weight feeders
load cell of loss in weight feeders ( resolution vs accuracy)
Volumetic feed rate of loss in weigh feeder
start up and shut down losses in continuous blender

Question 30

what is better in a low through put rates

Answer 30

semi continous or mini batch belnding Approach

Question 31

what are the benefits of CM?

Answer 31

higher quality, higher patient safety, faster time to market , reduced cost