1. Section IV Feeding Technology and Product Overview
Lucas Frei
Regional Sales Manager Ukraine

2. Why are Feeders Necessary?
To set the precise throughput to a downstream process
Continuous processes such as mixing or extrusion become “slaves” to the feeders
Provide an accurate blend of bulk solids and liquids for a formulation
Eliminate pre-mixing of solids/segregation
Using individual feeders for each component of the blend
Feeders are used to set the flow rates of both liquids and bulk solids.

3. Volumetric Feeding

4. Volumetric Feeding I Speed Regulated Volumetric Feeding: Motor Drive
Setpoint
Motor Drive

5. Gravimetric Feeding

6. Gravimetric Control Principle
Controller
Weight signal
Speed
Setpoint

7. Gravimetric Feeding Loss-in-Weight Feeding

8. Loss-in-Weight Principle

9. Refill Levels
Refill
starts
Refill
stops

10. Important Refill Considerations
Choosing the Proper Refill Device
Reaction Time of the Device
Device must be LEAK FREE
Material characteristics
Choosing the Proper Hopper Size for Refill
Choosing the Refill Times
Defining importance of accuracy during refill, particularly when low rate feeding

11. Bellows

12. Venting
Venting
with filter bag
Central venting

13. Feeding Modes There are two basic feeding modes: Batch Continuous
Gain-in-weight batch
Loss-in-weight batch
Continuous

14. GIW Batching via Volumetric Feeders
Volumetric feeders dose bulk material into a weigh hopper
Increase in collection hopper weight is measured
Scale’s weight info is used to control each feeder based upon setpoint or recipe
volumetric feeders
hopper on load cells

15. Gain-in-weight batch operation in slow motion

16. Gain-in-Weight Batch Systems
Advantages
Only one scale device for load hopper
Cost effective since feeders are volumetric
Well suited to large batches
Disadvantages
Total batch time is dependent upon the number of individual batch times necessary
Combination of large single batches and very small batches not as versatile (due to large taring values of the collection hopper)

17. Loss-in-Weight Batch Principle
Loss-in-weight feeders dose bulk material into a collection hopper
loss-in-weight feeders
collection hopper
Click for LIW Batch video

18. Loss-in-Weight Batch Systems
Advantages
Each ingredient is batched out in its own LIW feeder
Feeders can then operate simultaneously, making overall batching process shorter
Can also batch out variety of ingredients at different bulk densities and high variation in mix percentages with high accuracy
Used for minor and micro ingredient weighing where individual percentages and accuracies required are outside the realm of GIW or scaling applications (0.5% of full load )
Disadvantages
Higher initial investment for loss-in-weight feeders

19. Continuous Feeding
Benefits: • Online recipe control • No premix station required • No product segregation • Shorter residence time • No waste of premix

20. Feeding Types

21. Typical Feeders Used in Processing
Weigh belt feeders
Rotary Valves
Vibratory tray
Volumetric
Gravimetric/Loss In Weight
Screw Types – twin and
single screw
Gravimetric/Loss-in-Weight
Microfeeding

22. Weigh Belt Feeding Operation: Material is conveyed along a belt
Belt Speed
Drive
Command
Belt Tare Weight
Material & Belt Weight
Operation:
Material is conveyed along a belt
Belt is suspended on weigh bridges
Belt load is measured, belt speed then calculated by control unit

23. Weigh Belt Feeder Benefits
Low cost for high volumes of flow
Function easy to understand
Compact for high flow rates
Can be extended to use as a conveyor
Handle large particle size bulk material
Low power requirements
Works well in difficult environments

24. Rotary Valves Operation:
Series of pockets delivers material volumetrically to process
Advantages:
Simple design – good for free flowing materials
Can be designed for explosion containment
Disadvantages:
Not ideal for packing/cohesive materials
No good control on product delivery, i.e. pocket fill may vary
Difficult to manage and clean
Pulsating Discharge
Limited turndown capabilities

25. Vibratory Feeders Operation: Material is conveyed by vibration
Can be volumetric or gravimetric
Advantages:
Simple design – good for free flowing materials
Can also be good for difficult flow materials - high aspect ratio
Gentle on products where attrition may be an issue
Disadvantages:
Not ideal for packing/cohesive materials
No good control on product delivery, ie LUMPS IN TRAY
Limited turndown capabilities

26. Unique Drive Technology
Quick and precise control due to displacement feedback
Resonance tracking allows different configurations without adjustment
Strong vibration motor with four air gaps
Enhanced LWF Algorithm improves accuracy
Magnet
Tray
Feedback
Sensor N S N
(S) S
(N) N
(S)
Spring
Shock mounts
Coil

27. Screw Feeders Operation:
Material conveyed by either single or double screw
Can be volumetric or gravimetric
Advantages:
Twin screws can be good for cohesive materials
Accurate delivery of product
Disadvantages:
Design options are critical with regards to overall cleanability

28. Single Screw vs Twin Screw
Single Screw ideal for free flowing materials, high volumes
Twin Screw ideal for more cohesive materials
Twin screws have a “self wiping” effect
Twin screws can also provide more even flow to the process

29. Microfeeding as defined by K-Tron
Microfeeding is defined as the ability to feed powders consistently and in a dynamic method to a process, at rates as low as 20 gram/hour*
Can be provided in either volumetric or gravimetric design, with gravimetric resulting in highest accuracies at low rates
Can also be provided for batch or continuous feeding
It has been used in limited cases as a doser, but it is not recommended for constant on/off operation
* Reminder: 20 g/h = 0.33 g/min feedrate
1% 2sigma dev. (60s) = 3.3 milligram/min

30. Gravimetric Feeding Weigh Belt Feeding

31. WBF Control Loop
Controller
Setpoint
Speed
Weight signal

32. WBF Control Principle I
Single scale version

33. WBF Control Priniciple II
Twin scale version

34. Gravimetric Feeding Flow Metering

35. Smart Flow Meter Unique design features: continually free path
gentle handling of bulk material
easy to clean
no energy needed to transport bulk material
practically maintenance free
independent of bulk material
integrated autotare system
no moving parts
simple, robust design

36. Measuring Force FR
The resulting force FR is measured by the upper sensor station. FR

37. Measuring Principle I
The flow meter measures the force FR exerted by the material on the slide.
As with the belt feeder:
Massflow = F • v
g • l • cos a
v=?

38. Measuring Force FP
The resulting force FP is measured by the lower sensor station FP

39. Taring at the touch of a button
The K-SFM can easily be tared at any time by diverting the flow of material through the bypass.
SFM VIDEO

40. Bulk Solids Pump:a New Approach To Solids Feeding

41. Feeding Concepts Definition of a Bulk Solids Feeder
A method of bulk solid flow control based on the correlation between machine speed and discharge rate.
Typical conveying systems are:
Screw feeder
Belt feeder
Rotary feeder
Vibratory feeder

42. BSP Technology Ideal Feeder Characteristics: Gentle Product Handling
True Positive Displacement Action
Absolutely Linear Over Full Operating Range
Excellent Uniformity of Discharge
100% Active Discharge (minimal residual material)
Able to Handle Differential Pressures
Low Maintenance Design
High Wear Resistance
Low Power Consumption
Quick and Easy to Clean

43. Comparison of Feeding Concepts
Feature
Screw Feeder
Belt Feeder
Rotary Feeder
Vibratory Feeder
BSP
True positive displacement action No
Dependent on material
Yes
Linear over full operating range
Poor
(dep. on screw fill)
yes
Uniformity of discharge
(pulses)
Good
Active discharge
(no residual material)
limited
(product build-up in screw flight)
limited (product build-up on belt)
Bad
(product build-up on the rotary wall)
Unaffected by differential pressures
Limited
Mechanical & maintenance simplicity
Wear Resistance
Very good
Power Consumption
High
Medium
Low
Product Degradation
Very low

44. Lock-Up Principle
The BSP principle provides continuous, positive displacement volumetric control by exploiting the phenomenon known as lock-up.
LOCK-UP

45. BSP Video Clip
click on the graphic to start the video

46. Liquid Feeders

47. Feeding Liquids Volumetric Loss-in-weight
Depending on the application and accuracy required, two feeding modes are possible:
Volumetric
Loss-in-weight

48. PID Control Principle setpoint pump flow meter controller drive
command DC
motor
current
motor drive
thoughput feedback

49. Design The liquid tank is mounted on either 3 SFT‘s or a scale
Flexible connections to the pump which is independent of the weigh system
The controls are standard K-Tron loss-in-weight controls

50. K-TRON Weighing Technology

51. The Principle
The K-SFT supplies a fully compensated true weigh signal.
* ASIC: Application Specific Integrated Circuit

52. SFT Features One-time only calibration by manufacturer
Integrated linearization and temperature compensation
High accuracy and reliability in any environment
Fast sampling time samples per second
1: 4`000`000 resolution in 80ms
Improved filtering techniques - real time calculation - not just sample averaging
Simultaneous sampling/processing

53. Improved Performance

54. Accuracy

55. Prevention of bridge building with difficult flowing materials
ActiFlow
Prevention of bridge building with difficult flowing materials

56. Hoppers & Agitation AC Agitator Drive Vertical Agitator
Horizontal Agitator

57. Vertical Agitation Requires additional headroom above the feeder
Heavy motor on lid can make servicing difficult
Needs a separate motor starter (DOL)
Causes clean-ability issues.
Expensive

58. Poor Flow in Hoppers = Poor consistent feeding
Difficult powders:
May get compacted
Form ratholes & bridges
Result in operation:
Production interruption
Quality problems
Screw feeder accuracy is a function of consistent screw fill
Ratholes or bridges

59. Alternative Solutions for Improved Hopper Flow
Design Options
Vertical Agitation
Flexible Elastomer Liners
(eg FlexWall, Shear Hoppers)
Bin Vibrators
Air Injectors (eg Magic Mushrooms)
Elastomer Coatings

60. Hopper Flow Aids – Pros and Cons
OPTION
PROS
CONS
Vertical Agitators
May be better suited for Large Hoppers
Require additional headroom for operation and maintenance
Can cause weight disturbances in gravimetric feeders
Cleanability and accessability are concerns
Flexible Liners
Keeps material fluid in hopper
Can cause additional packing and densification of cohesive materials
Liners can stain =cleanability concern
Can cause weight disturbances
Bin Vibrators
External to process
Can cause additional packing of material
Can cause weight disturbances depending onfrequencies

61. Flow Aid for LIW feeders - ActiFlow
Click for Actiflow video

62. ActiFlow Design
The ActiFlow Device is bolted to the outside of the hopper wall, with no product contact. It is ideal for applications which require a stainless steel hopper.
The special design ensures material activation has a minimal effect on the weighing system.

63. Questions?