Transcript Nitrogen Tire Inflation Membrane vs. PSA

Nitrogen Tire Inflation
Membrane vs. PSA
July 18, 2015
Parker Hannifin PSA
• We make PSA units in
Baltimore
• Typically for high flow,
high purity applications
• Do not believe it
meshes w/ auto market
due to increased
attention required
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PSA System Operation
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The Case for PSA
• Touted as new technology
• NOTE: It is an old technology that is well known outside Autos
• Price per scfm
• Fuzzy math on the flow rate
• Lower price, lower quality from China
• NOTE: Nearly equivalent price, or higher in USA
• Air Factor
• Much better at higher purities
• NOTE: Relatively close at lower purities
• Dewpoint
• Will approach -70F vs. -40F for membranes vs. +45F for dry air
• NOTE: 11ppm vs. 79 ppm vs. 6500 ppm @ atmosphere
• Purity
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• 99.99% is possible, usually touted at 99%
• NOTE: Need about 97%+ in the tank to get 95% in the tire
PSA Facts – Carbon Molecular Sieve
• CMS
• Adsorbs oxygen under
high pressure, desorbs at
atmosperic pressure
• Controlled by valve cycling
• High grade CMS vs. low
grade CMS
• Has a finite life
significantly hampered by
contamination
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• Water or oil or oil vapor
PSA Facts – Contamination
• CMS behaves just like
a carbon filter
• Releases adsorbed
oxygen and water
vapor
• Oil, water and
hydrocarbon vapor
attach, plug up the
pores and compromise
life and performance.
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PSA Facts – Proprietary Fill Technique
• Ensures long term
performance
• Eliminates ratholing,
channeling, dusting, etc.
• Hampers long term
performance & life of unit
• Buffer differential pressure
• Fluidization
• Carbon integrity
• Vessel Sizing
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• Gas velocity
PSA Facts - Portability
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• If towers are not
packed properly,
carbon will shift as
moved
• As carbon shifts,
ratholing, channeling
and dusting will occur
• Units life &
performance is
compromised
• Very heavy and difficult
to move around,
especially on casters
PSA Facts – Maintenance
• Membrane: passive vs.
PSA: active
• Membrane is more
trouble free
• Solenoid Valves
• Frequent cycling - wear
• Maintenance team
• Stock replacements
• Controllers
• Valve timing
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PSA Facts - Pressure
• No benefit from higher
pressure found in most
auto shops
• One mfg advertises 8
scfm equivalent
membrane flow.
• True flow is 6 scfm
• At what purity?
• 40% drop 95% - 98%
• Say flow in equivalent
membrane is 8 scfm
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PSA Fill Times – No Tank
• N2 fill cycle: 8 mins
• Purge time: 6 mins
• Fill time: 2 mins
• Without tank, no N2
produced during
long purge cycle
• Compare
membrane vs. PSA
in 10 cf tire (40 cf
tot)
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• 5.1 scfm membrane
w/ tank:
• Makes N2 during
purge
• Cycle = 40/5.1 =
7.84 mins
• 6 scfm psa, no tank
• No N2 during purge
• 7 mins fill time
• Cycle: 7 mins + 6
mins = 13 mins
Parker Hannifin PSA Features
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PSA for Tire Inflation
• Built in China
• Quality?
• Issues?
• For sale? Ownership?
• Membrane & steel price
increase
• What’s best for customer?
• Deceptive flow
• Deceptive price
• What is true price?
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• Long term focus?
• Serviceability is now their
responsibility
• Reports of other Chinese
PSA providing 81% N2
• Tank often an option
• Membranes for stationary
units
• Couldn’t compete w/ portable
Take a Look Inside
• This is a picture of a PSA
unit designed for tire
inflation
• Compare w/ membrane
• Too many chances for
critical failures
• Not making money when
nitrogen is down
• Is this, coupled with all of
the other factors, truly worth
the savings?
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