theories and pracvitces in rubber mixing technology frank.j.borzenski
DESCRIPTION
Theories and practices in rubber mixing technologyTRANSCRIPT
Theories and Practices in Rubber Mixing Technology
Mill Room Mixing TechnologyMill Room Mixing TechnologyMill Room Mixing TechnologyMill Room Mixing Technology
A seminar for the Indian Rubber CommunityA seminar for the Indian Rubber Community
November 2010November 2010November 2010November 2010presented bypresented by
Frank J. Borzenski Frank J. Borzenski
TOPICS
• Basic Rubber Mixing Technology and Machinery
• Material variables affecting batch mixing
T ti l d I t hi b t h i• Tangential and Intermeshing batch mixers
• Batch mixer mechanical options affecting mixing
• Operating variables affecting batch mixing
• Mixing procedures and operating parameters
Optimizing the mixing process• Optimizing the mixing process
BASIC RUBBER MIXING TECHNOLOGY
Type General Advantages Disadvantages
PRIMARY COMPOUNDING MACHINERY
Mills First rubber compoundingmachine(not generally a primary mixer. they are used as a post mixer forming device)
- Very versatile- Broad range of shear capability- accepts all feed forms - good for short production runs
- difficult to control- difficult to automate- batch to batch variation (due
to weighments, feeding, andheat & shear history)
- dirty operation- safety considerations- low output- varying power demand- labor intensive
Batch Mixers Most common rubber compounding machinery
- accepts all feed forms - high output- can be automated good for short production runs long life expectancy broad range of shear capability
- varying power demand- batch to batch variation
(mixer control & weighments)- post mixer variable product
heat history capital intensivebroad range of shear capability capital intensive need post mixer forming can be labor intensive
Continuous Mixers Specialty applications high output energy efficient ease of process optimization
need free flowing feed (particulate rubber)
require sophisticated weigh & p p easily automated uniform product shear & heat
history
q p gfeed systems
not applicable for short runs capital intensive may need post mixer forming
Twin Screw Extruders Twin Screwextruders
- newer technologySpecialty applications
energy efficientease of process optimizationextruders - Specialty applications ease of process optimization
easily automated geometry optimized for use uniform product shear & heat
history
C ti lConventional Batch Mixing
Mill RoomMachinery
Mixer & Mill (s)Mixer & Mill (s) Mixer & singlescrew extruderswith pushers(roller, pork chopor pellet head)
Mixer & twin screw extruder/ sheeterMixer & twin screw extruder/ sheeter
TANDEM MIXER CONCEPT
Primary MixerPrimary Mixer(with ram)
Secondary Mixer(without ram)
Post Mixer forming
CM – MILL INSTALLATION
Continuous Mixer
CM EXTRUDER INSTALLATION(Continuous Mixer and Extruder)(Continuous Mixer and Extruder)
“MVX” (Mixing Venting Extruder)
Material Supply Using Powder Pre-Mix Technology
Pre-Mix - (Distribute)
Dispersive Mixing
And ExtrusionAnd Extrusion
Material Supply Using multiple feeders
TWIN SCREW EXTRUDERS
Polymer addition
Filler & misc. Chemical addition
Venting
Plasticizer additionPlasticizer addition
Product extrusion
TYPICAL TWIN SCREW INSTALLATION
Basic Mixing Theory
The Quality Objectivee Qua ty Object e
QUALITY PRODUCT
PRODUCT POTENTIAL PROCESSABILITY
When properly fabricated the The product mix must easilyp p ypart must meet all physical
requirements
p ybe formed & cured Into the final
product shape
“PROCESS TECHNOLOGY”
CompoundingMachinery
Compound Ingredients MachineryIngredients
THE MIXING TASK
BASIC TYPES OF MACHINERY MIXINGS C S O C G
TYPES OF MIXING
REACTIVE DISPERSIVEHigh shear
DISTRIBUTIVEHigh shear
GLOBAL FLOW MODEL IN INTERNAL BATCH MIXERS
V tM
W ll M i d R iW ell M ixed Region
H ig h S h ea r R egion
qnw L
DISPERSIVE AND DISTRIBUTIVE MIXING
Raw Material Variables Affectingthe
Mixing Process
TYPICAL MATERIAL CONCERNS WHEN MIXING
• Polymer type, age, uniformity & purity• MW & MWD entanglements• Thermal & oxidative characteristics• Homogenization of single or multiple polymers
(phase morphological concerns-compatibly)• Environmental and geometric affects on the polymerspolymers
• Filler type (extending, reinforcing,& reactive fillers)• Age, uniformity, purity, reactivity
P ti l i d ti l i di t ib ti• Particle size and particle size distribution• Requirement to breakdown agglomerates or pellets • Possible forming of agglomerates• Requirements for efficient filler/polymer interaction
• Type of plasticizers, protective additives, reactive chemicals• Age uniformity purity reactivity• Age, uniformity, purity, reactivity• Lubricating affects of liquid and melting additives• Threshold temperature (melting) effects for incorporation• Maximum temperature limitations
COMPONENT CONSIDERATIONS“Feed Form Example”
(kW)
(410)
(NR)
(410)
(298)
(336)
(298)LBS. (50.9Kg)
(298)
(261)
(224)
(186)
PSI(32 ‘C)
(121 ‘C)
(149’C)(186)
(149)
(112)
lbs.(0.045) (0.136) (0.455) (4.55) (45.5) (KG)
AVERAGE WEIGH OF RUBBER FEED UNIT
COMPONENT CONSIDERATIONS“E i t l Aff t ” R bb F d T t E l“Environmental Affects” - Rubber Feed Temperature Example(temperature & % moisture))
100
NAT,L RUBBER MASTICATION
AVG POWER
60
80
MOONEY REDUCTIION RATE
AVG POWER
40
60% ofscalerange MIX TIME
0
20Legend--scale range
mix time 0-10 min.avg kw 0-200mooney reduction rate 0-10 M/min.
-10 4 21 320
RUBBER FEED TEMPERATURE DEGREES CENTIGRADE
(90 F)(14 F) (70 F)(40 F)
The
“Tangential” and “Intermeshing”
Batch Mixers
Banbury®or
Intermix®
BASIC COMPONENTS OF THE BATCH MIXER
AIR or HYDRAULICCYLINDER (s)(ram actuator)
HOPPER
ASSEMBLY
( )
HOPPER COVER
Rotor end plate & Dust stops
rRAMor WEIGHT
CHAMBERROTORS(Tangential or Intermeshing)
DROP DOORTHERMOCOUPLE INDROP DOOR OR END FRAME
Batch dischargingmechanismMixer motor drive
& reduction set(indicated mix temperature)
Mixer rotor torque demandTHE BATCH MIXER(Batch Mixing of a Tread Compound)
Ram position
Indicated mix temperature
Mixer rotor torque demand( g p )
F-270 2-wing =270 liter net chamber volumeF-270 standard hopper volume= 299 literstotal F-270 mixer & hopper volume=569 liters
Typical Fill factor = 0 75Mixer rotor input power
TIME
Typical Fill factor = 0.75Batch weight=228.8 KGComposite bulk density=0.588 KG/liter S.G. ( product) = 1.13 Kg/liter
V l f f d b d
389liters 203 liters
Volume of product based onMixing action causing a changeVolume of feed based on Composite Bulk density
Volume of product based on Product density
Mixing action causing a change In apparent density of the mix
29”
270 liters@ 75% fill
389liters
11.5””
569liters
270liters
75% fill after mixingFill after feeding ( generated gases & air is removed
from under the ram)
BATCH MIXER TECHNOLOGY
INTERMESHING TANGENTIALIntermix ® Banbury ®
Machinery in Application(BASED ON MACHINE SALES 2008 & 2009)
AREAS OF APPLICATION % OF INTERMIX® BATCH MIXERS IN
% OF BANBURY® BATCH MIXERS IN APPLICATIONBATCH MIXERS IN
APPLICATION MIXERS IN APPLICATION
TIRE COMPOUNDS
48 61
TECHNICAL RUBBER GOODS ie, seals, hose, automotive custom mixing etc.
46 16
WIRE AND CABLE 2 0WIRE AND CABLE
2 0
PLASTICS COMPOUNDING 4 23
100%
100 %
RATIO OF BATCH MIXERS SOLD
1.0
1.1
Note: the data is approximate
AREAS OF MIXER APPLICATION
Intermix ®&&
Banbury®• medium viscosity rubbermedium viscosity rubber
&plastic formulations
• general rubber goods
Banbury ®• high volume application
Intermix ®®• specialty rubber and plastic
• sticky materials• multiple step rubber mixing
applications(especially final mix of highviscosity compounds)
(low temperature compounding)• extreme quality applications•reactive mixing applications •single step rubber mixing applications
viscosity compounds)
TANGENTIAL MIXER
Dispersive Distributive
DISTRIBUTIVE & DISPERSIVE MIXING
Dispersive
Even speed or friction operationEven speed or friction operation
Tangential Mixer ST™ Rotorsg
0 - 0 RotorOrientationOrientation
0 - 90 RotorOrientation
0 - 180 Rotor0 - 180 RotorOrientation
INTERMESHING MIXERDISTRIBUTIVE & DISPERSIVE MIXING
DispersiveDistributive
DISTRIBUTIVE & DISPERSIVE MIXING
TEMPERATURE CONTROLLED SURFACE COMPARISON
300
350
200
250
300
me
[dm
3 ]
Tangential
100
150
00
Empt
y vo
lum g
Internal Mixer
0
50
E
IntermeshingInternal Mixer
0 2 4 6 8 10
Temperature controlled surface [m2]
TEMPERATURE CONTROLLED SURFACE COMPARISON
Surface-to-Volume Ratio vs. Machine Size
TEMPERATURE CONTROLLED SURFACE COMPARISON
100
120
Small
60
80
ea/ V
olum
e
40
60
Are
Large
0
20
1 2 3 4 5 6 7 8Machine Size
FEEDING EFFICIENCY - INTERMESHING VS. TANGENTIAL MIXERSFEEDING EFFICIENCY INTERMESHING VS. TANGENTIAL MIXERS
VIC™ SERIES INTERMIX® BATCH MIXER
Adjustable Rotor to Rotor Clearance
B t h MiBatch Mixer Mechanical Options
Aff ti Mi iAffecting Mixing
CRITICAL COMPONENTS TO BE DISCUSSED Ram PositionRam actuation(air or Hydraulic)
a os t oIndicator (RPI)
Ram /plunger/ weight design
Mixer sidesMixer rotor end platesMixer rotor end plates
Drop doordesigndesign
Mixer rotors
Dust stops
EFFECTIVE BATCH & CYLINDER PRESSURE
CYLINDER PRESSURE- air or hydraulic oil pressure applied to the piston(s) forcingpp p ( ) gthe weight down
“EFFECTIVE” BATCH PRESSURE- pressure applied by the bottom of the
weight on the batch
EFFECTIVE BATCH & AIR CYLINDER PRESSUREBATCH PSI = F (wt of components) + (PSI T x area top piston) (PSI B x area bottom piston)
PSI T(PSI ABOVE PISTON)
Install gaugefor P top
BATCH PSI = F (wt of components) + (PSI T x area top piston) – (PSI B x area bottom piston)AREA WEIGHT AREA WEIGHT
(PSI ABOVE PISTON)
PSI B( PSI BELOW PISTON)
90
LegendPSI(top)PSI(B)PSI (B res.)PSI (EFF.-1)PSI (EFF-res)
MIXER AIR CYLINDER PERFORMANCEIncreased pressurization time
Install gaugefor P bottom
( PSI BELOW PISTON)
BATCH PSI 50
60
70
80PSI(CYLINDER)
RESIDUEBATCH PSI(EFFECTIVE PRESSUREON BATCH)
10
20
30
40RESIDUE PSIBLOCKAGEFAST
PRESSURIZATIONSLOW PRESSURIZATION
0 15 20 30 40 50 600
TIME (SECONDS)
HYDRAULIC RAM BENEFITS
Eliminates compressed airrequirements
• Efficient application of high batch pressure
• Increase of process repeatabilitydue to the elimination of thevariations in the plant air supply
• Potential reduction in plantoperating expenses
• Options of adjustable layback
• Option of speed / position• Option of speed / positionprofiling
WtHYDRAULIC RAM PERFORMANCE
BATCH PSI = F (wt of components) + 2( (PSI T x area top piston) – (PSI B x area bottom piston)AREA WEIGHT AREA WEIGHT
Wtcomponents
Hydraulic ram Behavior
2500
seconds
hydraulic dn forcepressure
Ram pressurization time
PSI T(PSI ABOVE PISTON)
1500
2000
2500
c pr
essu
re
pressurehydraulic opposing forcepressurenet effective batchpressure
batch pressure
down force hydraulic
PSI B( PSI BELOW PISTON)
0
500
1000
Hydr
aulic
100 psi batch pressure
50 psi batch pressure
batch pressure
opposing force hydraulic
BATCH PSI( EFFECTIVE PRESSURE
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
time ( seconds)
( EFFECTIVE PRESSUREON BATCH)
CRITICAL WEIGHT PROCESS RELATED ITEMS
• Weight (ram or plunger) design• Weight (ram or plunger) design
• Weight to throat clearancesWeight to throat clearances
• Weight layback position
• Weight to rod connection
WEIGHT DESIGN (TANGENTIAL MIXERS)C O
•V bottom
Water Cooled Option
•V bottom(optional water cooling)
•Keel bottom * (optional water cooling)
* New Technology item
INTERMESHING PLUNGER OR WEIGHT DESIGN
or
•Contoured Keel Bottom™ or “V” bottom
•Water cooled (standard)
CRITICAL WEIGHT PROCESS RELATED ITEMS
“X” Weight to Throat Clearance “Y” Weight Layback Position
Too tight a clearance can cause: Too low a layback can cause:Too tight a clearance can cause:• Mix chamber seal off• Weight Jamming
Too wide a clearance causes:
y• Mix chamber seal off• Poor mixing (tunneling)• Reduced batch weight• Rapid mix temperature rise
• Blow by• Excessive noise, vibration & wear
p p
Too high a layback can cause:• Poor mixing
WEIGHT FULL DOWN POSITION (LAYBACK)
“Y” = Layback weight positiong p
Mixer Volumes (liters)FV LB(inches) NVFV LB(inches) NV
(Reference Volume) (LAYBACK) (NET VOLUME)
F-270 NST (257) 0 240 F-270 NST (257) 0.75 248 +8F 2 0 NST (2 ) 1 2 6 16
Increased usable volume can result in a larger batch weight
F-270 NST (257) 1.5 256 +16
g g
TANGENTIAL MIXER RAM / WEIGHT TECHNOLOGYRam “Y” Layback Position (fixed position)
Ram
Ram Cushion Pad & Spacer
Cushion Pads& Spacer
CHAMBER VOLUME SPECIFICATION
R f V lReference Volumeor Catalogue
Ram Full Down Volume
Net Chamber Volume
RAM POSITIONING SYSTEM & CONTROL PACKAGES
Basic Two Position Selection (Mechanical)• Discrete two position• Selectable pressure control• Selectable pressure control• Two packages sold• Reported 10% increase in productivity
Variable Layback with Pressure and Speed y pControl (hydraulic)•Infinite position and pressure control•Ran travel Speed & speed profile control
WEIGHT POSITION INDICATIONThe Tell Tale Rod
Tell-tale rodlocation
The Tell Tale Rod
Tell-tale rod directed through the hole in hopper cover plate
Tell-tale rod attached to sloping surface of weight
ELECTRONIC WEIGHT / RAM POSITION INDICATOR (RPI™)
ram position
Continuous Ram Position Monitor
ELECTRONIC WEIGHT / RAM POSITION INDICATOR (RPI )
60
70
80
90
100
otal
trav
el)
Signal Relating to Ramposition
0
10
20
30
40
50
m p
ositi
on (
% o
f of t
o
ram position
Sensor Location
24 volt power supply
-20
-10
00 2 4 6 8 10 12
time ( seconds)
ramSensor Location
Pneumatic Hopper Hydraulic Hopper
ELECTRONIC WEIGHT / RAM POSITION INDICATOR (RPI™)
The RPI Output & Batch Weight
ELECTRONIC WEIGHT / RAM POSITION INDICATOR (RPI )
Over Filled G d Fill U d Fill dOver Filled Good Fill Under Filled
The “RPI” Mix Topography & Process Optimization
Mixer
Indicated
Motor amps
Ram positionMix temp.
Ram position
Mixer motor power
Discharge Add oil Brush Load Rubber & Filler
MIXER SIDES SPRAY SIDE JET SIDEMIXER SIDES
Older Design Banbury® Sides
Drilled sideDrilled sideOptimized for maximum heat transfer
OIL INJECTION PORTS
CONVENTIONAL DUST STOPS(with process & lubrication oils)
The Banbury® Dust stop --- as an exampleStandard Hydraulic Design
(with process & lubrication oils)
Lubrication oil- seals and lubricates the (stationary) gland ring to (rotating) wear ring on the rotor. A majority of lubricating
Processoil
oil goes out of the assembly between rotating rotor and stationary gland ring and is collected in buckets attached tothe drip trays or is directed into a central collection reservoir. It is lubricating oil and need not be compatible with the product
oil
L b il mix. Should run when rotors are turning.
Process oil- is considered a purge oil to keep ingredients beingmixed from entering the clearances between the rotating rotor
Lube oil
and stationary rotor end plate. The process oil enters the mixing chamber and becomes part of the mixed batch. The process oil pump should be shut off when the drop door is open and product is not being mixed. There is a timer that shuts off the process oil pump after a signal is given. Excess process oil can cause mix quality and productivity issues.
CRITICAL PROCESS RELATED ITEMS (tangential mixer)
New standard with drilled passageways Old Design with
The temperature of the door top can affect mix quality and operating efficiency
New standard with drilled passageways Old Design with cored cooling
- too hot a door top can cause drop door jamming ( mechanical expansion between REP)
- too cool a door top can cause powder leakage
too hot or too cool a door top can cause product hang up (sticking)- too hot or too cool a door top can cause product hang up (sticking)
- too hot or too cool a door top can cause thermocouple error at low mix temperatures
THERMOCOUPLE DESIGNS(for mix temperature detection)
350
400degrees F Thermocouple response
100
150
200
250
300
insertion
0
50
100
0 5 10 15 20 25time
(seconds)
THERMOCOUPLE POSITIONSTangential Banbury® Mixers
End Frame Door TopTangential – Banbury® Mixers
THERMOCOUPLE FOR PRODUCT TEMPERATURE DOCUMENTATIONProtrusion heightFOR PRODUCT TEMPERATURE DOCUMENTATION
Hardened bushing
– Thermocouples are mounted in hardened bushings for increased support to extend life– The protrusion height can affect Thermocouple accuracy
Th l b iti ti ( b d d t d d d t t )– Thermocouple error can be positive or negative ( based on product and drop door temperature)
ROTOR DESIGN (INTERNAL) FOR TEMPERATURE CONTROL TYPES
Core Pipe CoolingCore Pipe Cooling(Flood Cooling)(Flood Cooling)
( )
Core Spray CoolingCore Spray Coolingp y gp y g(Spray Cooling)(Spray Cooling)
Core body & Wing Tip CoolingCore body & Wing Tip Cooling(Wing Tip Cooling)(Wing Tip Cooling)
2 piece rotor Tip & Body2 piece rotor Tip & Body2 piece rotor Tip & Body 2 piece rotor Tip & Body CoolingCooling
(“SC” (“SC” -- Super CoolingSuper Cooling))
TANGENTIAL MIXER ROTOR TECHNOLOGY
Production Rate and Rotor Alignment
Synchronous Technology & Production Rate
g
3000
3500
2000
2500
nds
/ hr friction
0-0 alignment0-90 alignment
500
1000
1500
Poun 0-90 alignment
0-135 alignment
0 67 % fill 71 % fill 74 % fill 78 % fill
Fill Factor
70 liter mixer with 2 wing RotorsReference formulation A (synthetic tire tread formulation)discharge based on indicated mix temperature
TANGENTIAL MIXER ROTOR TECHNOLOGYS h T h l & M Vi itSynchronous Technology & Mooney Viscosity
Average Mooney and Rotor Alignment
95
STD Deviation Mooney and Rotor Alignment
8
9
80
85
90
Moo
ney
Visc
osity
friction0-0 alignment0-90 alignment0-135 alignment
3
4
5
6
7
Std
Devi
atio
n friction0-0 alignment0-90 alignment0-135 alignment
70
75
67 % fill 71 % fill 74 % fill 78 % fill
Fill factor
0
1
2
3
67 % fill 71 % fill 74 % fill 78 % fill
fill factor
70 liter mixer with 2 wing Rotors70 liter mixer with 2 wing RotorsReference formulation A (synthetic tire tread formulation)
FUME & DUST COLLECTION
MIXER VENTING(fume & dust collection)
• Piping & Hood designT t l V l Fl
(fume & dust collection)
Side View Front View
• Total Volume Flow• Air Velocity (capture velocity)
Operating VariablesAffectingAffecting
Batch Mixing
PRIMARY OPERATINGO GVARIABLES AFFECTING BATCH MIXERS
• Batch Weight / Fill Factor• Mixer Temper (metal temperature control)• Mixer RPM• Feed Material Considerations (temp & form) • Environmental Effects• Mixer Applied Batch Pressure• Mixer Applied Batch Pressure• Mixing Steps and Procedures
BATCH SIZE CALCULATION
BATCH SIZE(THEORETICAL)(THEORETICAL)
batch wt. = (net mixer volume) (density compound) (fill factor)
Fill factor (Intermix ) = 0.85 (fill factor (Banbury®))
INTERMIX ® vs. BANBURY® BATCH WEIGHT & FILL FACTOR
Banbury ® ST™ equipped mixer @ 50-60 psi batch pressureIntermix ® NR5™ equipped mixer @ 65 - 75 psi batch pressure
140
160
80
100
120
LegendTangentialIntermeshing
ML 4@100 C
20
40
60g100 C
0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.90
FILL FACTOR FILL FACTOR
FLOATING WEIGHT POSITION INDICATOR
The RPI Output & Batch Weight
Over Filled U d Fill dOver Filled Good Fill Under Filled
MIX TOPOGRAPHY & PROCESS OPTIMIZATION
Ram bottoms at or close high power demand
INDICATED MIX TEMPERATURE
MIXER RPM
MIXER POWER
RAM POSITION
OPTIMUM FILL FACTOR (Banbury®)
50
46
48PRODUCTMOONEYML4
44
67 69 74 80
42
PROPRIETARY 67 69 74 80
% FILL
PROPRIETARYNR SINGLE STEP MIX
105C DISCHARG25 RPM 25 PSI BATCH
MIXER METAL TEMPERATURE & HEAT TRANSFER
T t C t lTemperature Control - Maximum Productivity
Optimum Quality- Optimum Quality
Heat Transfer Optimum Material Flow(Stick-Slip)(Stick Slip)
MIXING ACTION “BANBURY®”
DispersiveDistributive
Dispersive
Even speed or friction operationEven speed or friction operation
BANBURY® METAL TEMPERATURE REQUIREMENTS
Component Desired Effect
Rotors release of product mixDoor top release of product mix / adjust to get TC accuracyWeight / Ram release of product mixWeight / Ram release of product mixRotor end plates release of product mix
Sides slight friction of product mix against surfaceSides slight friction of product mix against surface
BANBURY® TCU SETTINGS (starting points)( ll t t ºF)
Polymer Type Rotors Sides Door(all temperature ºF)
Natural rubber (NR) 90 120 90Synthetic rubber (SBR) 140 120 120Natural / synthetic bl d 110 120 110blends 110 120 110
EPDM / EPR 120 160 120Nitrile (NBR) 80 90 90Chloroprene (CR) 140 90 90Butyl (IIR) 70 80 70
TEMPERATURE CONTROL UNIT “TCU”
ST™ ROTOR PERFORMANCECure Uniformity & Rotor TemperatureTread Compound – Final Mix
F-270 4wSTmixer body @49 C (120 F)mixer door @ 27 C (81 F)fill factor @ 75%fill factor @ 75%batch Pressure @ 4.1 bar (60 psi)mixer @ 30 rpm70 sec rm dn mix time
rotor water @ 71 C (160 F)
70 sec rm dn mix time
rotor water @ 60 C (140 F)rotor water @ 60 C (140 F) rotor water @ 49 C (120 F)
INTERMIX® TCU SETTINGS
Legendinput KWH
Intermix Performance data
0.2
0.25
0.3 energy in mix (kwh)
kwh Intermix Performance data
0.05
0.1
0.15
60
70
Legend% removed by mixer% into mix% mic looses
% of input40 50 60
K0 mixer NR-5 rotorsFF= approx 70%rpm= 60synthetic rubber final mix
Mixer TCU setting C
30
40
50 Kwh
40 50 6010
20
K0 mixer NR-5 rotorsFF= approx 70%
Mixer TCU setting CFF= approx 70%rpm= 60synthetic rubber final mix
g
MIXER RPM & MIX TIME (TYPICAL BEHAVIOR)
5
6
Cycle Time & Mixer RPM
2
3
4Mix Time(minutes)
0
1
0 20 40 60 80 100 120
Mixer rpm ( 3D 2 wing)
BANBURY® MIXER RPM, TCU SETTINGS & MOONEY VISCOSITY
100 90
Mixer rpm, Mixer temperature, Mooney Viscosity, & Cycle time
BANBURY® MIXER RPM, TCU SETTINGS & MOONEY VISCOSITY
60
70
80
90
60
70
80
Legendcycle time 100%=10 minutesMooney 0-90 ML4% f f ll
70 F mixer
30
40
50
60
30
40
50Mooney 0-90 ML4std deviation 100% = +/- 66.7% of full
scale mooneyML 4
90 F mixer
28 56 84 1120
10
20
0
10
20140 F mixer
28 56 84 1123D mixer 2 wing rotor100 lb. #4SS Natural43 PSI batch pressureuniform feed @ approx. 10 Lb. chunks70 F f d t t
mixer rpm 70 F mixer tcu setting
90 F mixer tcu setting
140 F mixer tcu setting70 F feed temperaturedischarge @ 285 -300F
140 F mixer tcu setting
COMPONENT CONSIDERATIONS “Feed Form”
(kW)
(410)
(298)
(NR)
(336)
(298)
(261)
LBS. (50.9Kg)
PSI
(32 ‘C)(121 ‘C)
(224)
(186)
(149)
(112)
(121 ‘C)
(149’C)
(0.045) (0.136) (0.455) (4.55) (45.5) (KG)
A AG G O
(112)
lbs.
AVERAGE WEIGH OF RUBBER FEED UNIT
COMPONENT CONSIDERATIONS “ENVIRONMENTAL EFFECTS”
NAT,L RUBBER MASTICATION
COMPONENT CONSIDERATIONS ENVIRONMENTAL EFFECTS
* TEMPERATURE
* HUMIDITY80
100AVG POWER
60% ofscale
MOONEY REDUCTIION RATE
20
40
Legend--scale rangemix time 0-10 min.avg kw 0-200mooney reduction rate 0 10 M/min
range MIX TIME
-10 4 21 320
mooney reduction rate 0-10 M/min.
RUBBER FEED TEMPERATURE DEGREES CENTIGRADE
(90 F)(14 F) (70 F)(40 F)
Effective batch pressure guidelines
Tangential Mixer Intermeshing MixerT i l 1 4 5 b 4 6 (7) BTypical Operating range*
1.4 - 5 bar20 - 72 psi
4 - 6 (7) Bar68 - 87 (102) psi
Tangential Mixer- use very low (float) effective pressure during discharging the batch, when injecting oil and
low effective batch pressure when mixing low viscosity products to prevent tunneling.- use high effective pressure at the start of the mixing cycle and when mixing high
Vi it d t b i i dViscosity products are being mixed- using high effective pressure mixing at the start of a mixing cycle and low pressure mixing
at the end of the mix cycles have resulted in significant process quality and rate advantages
Intermeshing Mixerg- use very low (float) effective pressure during oil injection and when discharging the batch-Use maximum pressure to minimize cycle time- Use lower effective pressure to extend cycle time and improve mixing if required)
*Note : (float) is the pressure applied to the batch due to the weight of the ram/weight assemblyNote :- (float) is the pressure applied to the batch due to the weight of the ram/weight assembly- effective pressures above and below the typical range are possible based on the
application and stage of the mixing process
Mixing ProceduresAnd
Operating Parameters
(the Art of Rubber Processing)
MIXING PARAMETERS, STEPS & PROECEDURES“The Art of Mixing”
I. MIXING STEPSSINGLE STEP MIX
ti l i l t
III. MIXER OPERATING PARAMETERS- % fill(batch weight)
The Art of Mixing
- conventional single step- upside down single step- process specific single step
MULTIPLE STEP MIX
( g )- temper ( TCU settings)- ram pressure- mixer speed
MULTIPLE STEP MIX- premastication (optional )- master batch- remill (optional )
fi l i
IV. MEANS OF CYCLE CONTROL- time- indicated temperature
- final mix
II MIXING PROCEDURES
- energy (kwh)- torque (power hp or kw)- other ( i.e., rotor revolutions)
II. MIXING PROCEDURES- order of additions- number of additions- number of ram cleanings (brushes)- procedure required for reactive compounding- discharging procedures
SINGLE PASS MIXINGSingle pass addition procedure, (simple conventional)
1. load rubber & any peptizers or AO2. load fillers & misc chemicals & cures ( cure may be added with brush)3 l d / i j t il3. load / inject oils
4. (ram down mix, brushing the ram is optional then discharge)
Single pass addition procedure, (Upside down)1. load all fillers , chemicals , oils, & cure (cure may be added with brush)2. load rubber
3. (ram down mix, brushing the ram is optional then discharge)
Single pass addition procedure ( process specific)- steps can be combined1. load rubber & any peptizers
2. (ram down mix)3 load fillers ( possibly multiple additions) & misc chemicals3. load fillers ( possibly multiple additions) & misc chemicals
4. (ram down mix, brushing the ram is optional)5. load oils (ram up or inject with ram down under low pressure)
6. (ram down mix )7. load cures
8. (ram down mix, brushing the ram is optional then discharge)
MIXING PROCEDURES (Multiple Step Mix – 2 or more passes through the mixer)First pass (to reduce viscosity, combine rubbers, distribute chemicals)
1. add rubber & any peptizers or AO2. (ram down mix & discharge)
Second pass (to disperse & distribute fillers & misc chemicals & mix oils)1. load First pass & fillers ( possibly multiple additions) & misc chemicals2. (ram down mix, brushing the ram is an option)3. load oils 4. (ram down mix & discharge)
Third pass ( optional) (to reduce viscosity and improve dispersion)Third pass ( optional) (to reduce viscosity and improve dispersion)1. add second pass ( additional fillers are sometimes added)2.(ram down mix then discharge)– possible 2nd addition of fillers and/ or misc chemicals)
Fourth pass ( to add the curing package and possibly reduce viscosity)(can be accomplished on a post mixer mill using predispersed cure package)
1. add ½ of previous pass 2. add cure package3. add ½ of previous pass4. (ram down mix, brushing optional, then discharge)
MIXING PROCEDURES (Mix Step Events Options & Details)
Order of addition of formulation materials1. Addition sequence of materials
MIXING PROCEDURES (Mix Step Events Options & Details)
Number of additions1. Multiple additions followed by ram down mixing of fillers may be required to improve
mix quality in a mix cycle
Number of ram cleanings1. Multiple ram raises to clean the ram and reduce mix temperature rise. Mixer rpm
may be lowered to reduce mix temperaturemay be lowered to reduce mix temperature.
Discharging procedure (option 1. highly recommended)option 1. float ram , open drop door, dwell door open , close drop door , raise ramoption 2 raise ram , open drop door , dwell door open , close drop dooroption 3 float ram, open drop door, dwell door open, raise ram, close drop door
OPERATING PARAMETERS SELECTION CONSIDERATIONS•Batch weight
•amount to be added in each addition if multiple additions of filler are required
OPERATING PARAMETERS SELECTION CONSIDERATIONS
filler are required
•Mixer rpm•Mixer rotor speed during feedingMi er rotor speed d ring ram do n mi ing•Mixer rotor speed during ram down mixing
•Mixer rotor speed when brushing•Mixer rotor speed when discharging
•Mixer ram effective batch pressure•Pressure during ram down mixing for each event•Ram travel time & pressurization time
•Mixer Temperature control unit settings•Rotors•Sides•Drop door•Rotor end plates•Mixer ram (if temperature control is available)
MIX CYCLE CONTROL (typical)
• Time ( from initial ram down or for each event)
MIX CYCLE CONTROL (typical)
• Indicated Mix Temperature
• Energy (KWH or HP-Hr) ( from initial ram down or for each event)Energy (KWH or HP Hr) ( from initial ram down or for each event)
• Rotor revolutions
• Torque or Power (Kw or Hp)
(combination of above)
The Optimizationof the
Mixing Process
Single step mixing (an approach to process optimization)
Event Description rpm batch PSI time (sec. KWh1 load polymer,all black, chemicals ,oils ,fillers ,cures 10 up 17 0.092 ram down mix to 175 F 50 50 50 2.663 raise ram and brush 30 up 20 1.01 4 ram down mix to 225 F 25 30 30 1.875 discharge batch- float ram open, drop door& dwell 15 sec 30 up 30 0.00
close drop door and raise ram 147 5.72
(loading)(di h & k Event 1
Event 5(discharge & makeready)
Event 2Event 4(ram down mixing)(ram down mixing)
Event 1
Event 3(Brush-clean ram)
Event 1
Event 2Event 4
Event 5
Event 3
The Batch Mixer
Tangential Intermeshing