Run Dry in Container Handling
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Run Dry
• Functions of lubrication
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Reduce friction
Even relatively instable containers will slide
Extended wear life of chains and components
Reduce energy consumption
Keep friction etc. at constant level
Debris is either repelled or washed down
System stayes relatively clean
Reduce the noise
No static charges are being built up
PET- run dry
• Customer asks for a dry system
• Question:
1. Do conveyors need to be dry?
or
2. Can lubrication not be tolerated?
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1. Conveyors need to be dry
• Solution: use plastic chains with dry lubrication
• Advantage:
• System is ‘dry’, some systems use as little as 10 L
lubricant per line per year!!
• System is lubricated so friction is reduced with all
advantages resulting from that
• Note: dry lubrication is not ‘ripe’ yet, supplier
must take responsibility and give performance
guarantees!!
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1. Conveyors need to be dry
Plastic chains lubricated with silicon based spray
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2. Lubrication cannot be tolerated
• Success depends on many factors:
• Container stability
• Friction between chain and container
• Speed
• Lay-out
• Other parameters
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Container Stability
• Formula: calculate critical friction
coeff.: Fc = R/HS
• R=Radius container base
• HS=Height center of gravity
• Example: stella bottle
• Fc=R/H=24/100=0,24
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Container Stability
R/HS > Fw => sliding
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R/HS < Fw => toppling
Stability of Petaloid Bottles
R becomes R1
With 5 feet: R1= cos36*R = 0,81*R
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Friction
• Friction is influenced by:
• Flatness of chain surface and gaps etc.
• Pollution of the surface
• Wear
• Humidity
• Quality of PET Preforms
• Temperature
• Question: what friction coefficients can be used
for calculations?
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Friction
• Friction of PET on plastic chain based on practical
experience (tolerance +/- 15%):
Friction PET
on:
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DRY
Lubricated
XLG
0,2
0,15
HP
0,18
0,14
PS
0,16
0,14
PS is still the best material for PET
0.30
0.25
0.20
LF
HP™
0.15
PS™
0.10
0.05
0.00
Cans
Glass
Paper
PET
Friction of PET on several Rex Materials without lubrication
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Lay-Out
• Critical are areas where:
• Bottles are accellerated or slowed down
• Conveyors are at an angle
• Bottles collide unsupported
• Chains are being polluted or occasionally get wet
• Curves (and the hinge) can heat up; UHMWPE has a
low PV-Limit!
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Other Parameters
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Electro-static charges
Wear Life of chain
Wear resistance of chain
Dry-in of cleaning agent
How well remain the bottles their shape?
With empty bottles: aerodynamics
Friction, shape and contact-heigth of guide rails
References Real Run Dry
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Successful with Rexnord chains
Fernbrook spring (water jugs), Milton, Canada
Coca Cola Londonderry, USA
Robinsons Softdrink, Norwich, UK
Other references
• Customers who had been promised run dry but
found out lubrication was required
• Volvic, France
• Levissima, Italy
• Acqua Vera, Italy
• Coca Cola Wakefield, UK
• Cott Beverage, UK
• Vrumona, Holland
• Coca Cola Grigny, France
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Conclusion
• Under perfect conditions the decision to run PET
without lube depends on:
• Bottle stability and friction on the chain
• Rule of thumb:
• If bottle stability factor Fc < 0,17:
Lubrication is necessary
• If bottle stability factor Fc > 0,25:
run
dry is possible
• 0,17 < Fc < 0,25: run dry can only be
successful under strict conditions
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Dry Lubrication
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Agenda
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What is Dry Lubrication
Features and Score of All Lubrication Systems
Products on the Market
Experiences
What is Dry Lubrication
• An automatic lubrication system with dosing units
that put very little lubricant on selected places
• Lubricant can be water or oil based, with teflon or
solid silicon micro-particles
• The most critical part is how the lubricant is
distributed on the chain:
• Brushes
• Shoes
• Spray
• It can be applied also inside the curves
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What is Dry Lubrication
Dosing unit
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What is Dry Lubrication
Brush distribution system
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What is Dry Lubrication
Wear shoe distribution
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What is Dry Lubrication
Chain surface lubrication
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Under the chain lubrication
Benefits (1)
• Dry floors: no water, foam or slime on the floors, which is unsightly & causes
accidents due to slipping
• No attack on equipment, bearings, motors and floor areas
• No slime or soap scum build up, on or under the conveyors
• Difficult-to-clean drip trays can be removed. Reduced hygiene schedules,
bacteria problems and the smells associated with it
• No false through-out from bottle inspector due to foam on bottom
• No soapy mess in the labellers or packers resulting in no package damage
• No (wet) lube carry-over onto trays and foils, no mould growth and more
stable pallets
• No ‘bacteriostatic’ lube in waste water system
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Benefits (2)
• Environmental
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Water consumption is reduced
Reduction in lube used versus wet lube.
Effluent treatment is greatly reduced
Total breakdown of lube in the waste water system
Reduced power consumption with no increase in forces during bottle build back
conditions
• Equipments
• Reduces the coefficient of friction to the wet lube standards so therefore reduces
wear and greatly extends the lifetime of conveyors and wear strips
• Motors, drive shaft's, sprockets etc have benefited from large reductions in load
and back pressure
• Production
• With virtually no falling bottles, production will benefit from less stoppages, a
better consistency of product and higher yields leading to increased line utilization
and efficiencies
• Cleaner, safer and more efficient environment
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Features and Score of Lubrication Systems
reduces chain wear
inhances product stability
reduces energy consumption
acts as a cleaner
prevents bacteria growth
is not sensitive to water hardness
does not leave deposits
does not need drip trays
does not need distribution end dosing system
is preventing static electricity build-up
prevents powder build-up
Run Dry
0
0
0
0
3
4
4
4
4
0
0
Just Water
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1
1
1
0
0
0
0
1
4
4
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Water&Soap Dry Lubricant
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4
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4
2
4
4
2
4
4
3
0
4
0
0
4
3
4
3
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Products on the Market
• CHP
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They claim to be the inventor
Good installed base in EU
Use wear shoes to distribute lubricant
They use XLG chains as reference
• Interflon
• Lubricant based on Teflon micro-particles
• They were the first lubricant supplier of CHP
• Use brushes to distribute lubricant
• Ecolab DryExx
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Lubricant based on Silicone micro-particles
They have a contract with CCE in USA
Use spray to distribute lubricant
They show XLG chains as reference
• DryLube
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Lubricant not based on Teflon, They sell the full service
They are based in UK, main customer base is there
They are certificated by CCE (UK)
Use brushes to distribute lubricant
• Diversey DryTech
• Use spray to distribute lubricant
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Experiences
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CHP in CC Antwerpen and SPA gave great results
DryExx is giving good results in CCE USA
DryLube gave good results in CCE UK
Diversey DryTech gave good results in Nestlè
Waters and CCE in France
• All report excellent results with XLG acetal chains,
some reported bad results with NG
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Water Lubrication
Recommendations and
Troubleshooting
„Hard Water“
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What is hard water?
• Hard water is a term for water which has high mineral
content
• Mainly calcium (Ca) and magnesium (Mg) carbonates
and other metal ions
• All fresh water resources contain these minerals
• The quantities of the minerals vary – depending on the
geographical region and the geological formation the
water went through
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Problems caused by hard water
• Hard water causes scaling
• Scale is caused by water evaporating and leaving behind
the mineral deposits
• These deposits are also known as limescale
• Decreases the life of chain, sprockets, wearstrips etc.
• Deposit build up around the link and the pin – sandpaper
effect
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Problems caused by hard water
Scaling on pin
and hinge
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Levels of hard water
• Several different scales with different units
• Most common units are:
• mg/l CaCO3 Eq. (Calcium carbonate equivalent)
• Parts per million weight/volume (ppm w/v or ppm m/v)
• °f (french degrees) >> 1 °f = 10 mg/l CaCO3 = 10 ppm
• Others:
• mmol/l
• 1 gr/U.S gal
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Levels of hard water
• Description of hardness correspond roughly with ranges of mineral concentrations:
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Soft: 0 - 20 mg/L CaCO3 Eq.
Moderately soft: 20 - 40 mg/L CaCO3 Eq.
Slightly hard: 40 - 60 mg/L CaCO3 Eq.
Moderately hard: 60 - 80 mg/L CaCO3 Eq.
Hard: 80 - 120 mg/L CaCO3 Eq.
Very Hard: >120 mg/L CaCO3 Eq.
• Behaviour of the hardness is also affected by
• the precise mixture of minerals dissolved in the water
• the water's acidity or alkalinity (pH)
• temperature
• Accelerated wear problems are expected due to hard water when
• the CaCO3 present is more than 250ppm (or higher than 20 French degrees)
• and the pH is higher than 7.
• >> elevated temperatures will also increase the crystal size
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Prevent scaling on chain and conveyor
1)
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Water softening
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Through so called „ion exchange units“
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Physical-chemical process which filters the water through
exchange media (e.g. resin with positevely charged sodium
ions)
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Relatively cheap, but the unit itself needs occasional
maintenance
Prevent scaling on chain and conveyor
2) Water treatment
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Chemical process
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Additives (Chelating agents) mixed up to the lubricant water to
prevent mineral deposits
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Basically EDTA (Ethylene Diamene Tetracetic Acid) concentration based on hardness condition of the water
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Increases lubrication
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Consult Lubricant Supplier
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Longer chain life due to reduced friction, but can be costly
because of constantly need of chemical additive
Prevent scaling on chain and conveyor
3)
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Soap lubricant
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Soap lubricant helps to keep the mineral deposits in
suspension
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Can be very efficient
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Depending on the water hardness
Running only with water?
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Seems to be a good idea >> no lubricants means less
process costs
Debris or spilled products are flushed away continously
- Very limited reduction of friction
- No reduction of bacterial growth
- Needs constant monitoring of mineral concentration
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Running dry?
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Reduced / no lubrication – lower costs
No slippery floors, no trouble with tough water pollution
regulations
• Rexnord has more than 20 years of experience in
succesfully dry running applications with LF, HP and PS
chains
• Specially formulated PS material
• Higher PV Limit allows 50% higher speed
• Optimized for PET – lowest friction available
• Various combinations of factors affect each conveyor’s
ability to be run economically without lubrication or with
reduced lubrication (see Run Dry section for details)
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Conclusion
• Every plant is different as to the water used in their
processes.
• Resolutions must be determined by contacting the water
softener, lubricant supplier, or a specialized water
treatment company.
• The final selection is generally based on cost, water
quality, and owner or operator preference.
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