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創新需求需求再造The Concept of the Basic
Liquid
主講人 : 龍仁生
技術研討資料
創新需求需求再造
Topics The key point to the filter Filter Cartridge
Filter type Depth fiber, Membrane, Hollow Fiber…
Filter Device Membrane, Support…
Membrane Characteristic Retention Wet-ability --- De-wet
Filter Housing SS, PFA, PVDF,PP…
How to choice an optimal filter
創新需求需求再造
The key to filter in Chemica • The Filter pore size / Retention
– How much ? 0.1um, 0.2um…
– Lower filtration rate, Higher retention
• The Chemical Compatibility / Pre-wetting – PTFE
– UPE
– PP
– Nylon
• Cleanness• Low Hold Volume
創新需求需求再造
Typical Depth Filter Structure
創新需求需求再造Manufacturing Process
Stretched Polymeric Membranes e.g. PTFE
創新需求需求再造 Manufacturing Process
Cast Polymer Membranes e.g. PVDF
創新需求需求再造
Manufacturing Process
Membranes Track Etched e.g. Polycarbonate
創新需求需求再造
Membrane Characteristics
"Pore size" (maximum pore size = "retention rating )
The largest sized pores in a filter
"Porosity" A measurement of the openness of a filter i.e. 80% porosity equates to 80% open
volume, 20% material
"Pore size distribution" The range and frequency of pore sizes
which make up a the filterThat is why HA
創新需求需求再造Typical Filtration Devices:
Pleated Cartridges Filter "pack" contains membr
ane, plus upstream & downstream fibrous supports.
Supports can be a source of particles .
Pulse pressure is a potential shedding source
It is not easy to prewet and flush.
PermeateFlow Path
Inlet Flow
Path
創新需求需求再造Typical Filtration Devices:Stacked Disk Cartridges
Downstream components are rigid and cleaner than other membrane supports.
Excellent in pulse pressure shedding.
Horizontal disks prevent efficient gas venting
FluidFlowPath
Permeate
創新需求需求再造
Typical Filtration Devices:Hollow Fiber Cartridges
Filter area can be greater than pleated structure
Benefits of self-supporting, high surface area, high flow.
Used mostly in water filtration and photochemical.
Low pressure drop
創新需求需求再造
Capture by Sieving / Interception ---
Hard Particle--- Bridge/ Cake effectSoft –Gel/Micro-bubble
Hard ParticlesSoft Particles
Filtration Retention Mechanisms:
創新需求需求再造
Retention Mechanisms:
Very small particles in liquids have a negative charge and can be captured by attraction to a positive charge in a filter
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Capture by Adhesion / Adsorption
創新需求需求再造
過濾在時間的變化
0
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10
15
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過濾
Shedding
過濾Shedding
過濾
Sheddingparticlel
Time
Time
壓差
創新需求需求再造
創新需求需求再造
Hydrophobic Vs Hydrophilic
Hydrophilic: Wetting smoothly with, water.". No pre-wetting
Hydrophobic: Fear of water; Tending not to combine with water. Requires pre-wetting.
創新需求需求再造
Hydrophobic Vs Hydrophilic
Contact Angle is the measure of Wettability
Hydrophobic
< 90?
Hydrophilic
No contact angle 90? > 90?
Low contact angle = HydrophobicHigh contact angle = Hydrophilic
i.e.
創新需求需求再造
創新需求需求再造
PTFE membrane surface energy is 18 dynes/cm; PTFE has a higher affinity for air than water. Gas bubbles stick to the membrane surface, forming nucleation sites.
As more gas bubbles pass through the pore, these nucleation sites grow and begin to block the pore.
Finally, the pore completely fills with gas, effectively blocking the pore and rendering it unusable. As more pores in the filter dewet, the flow through the filter dramatically decreases.
What is Dewetting and how can it impact a process?
SC1SC2H2O2
NH4FPiranha
創新需求需求再造
QuickChange membrane surface energy is 35 dynes/cm; when wet, this membrane has a higher affinity for water than air.
Dissolved gas bubbles do not stick to the membrane surface, eliminating the formation of nucleation sites.
Dissolved gas bubbles are swept through the pore, leaving the usable filtration area intact. Flow rates are maintained over extended periods in use.
QuickChange Filters are Non-Dewetting
SC1SC2H2O2
NH4FPiranha
Non-Dewetting Technology
創新需求需求再造
Flow in one direction (prevents air entrapment) Flow from upstream side into core 60:40 IPA water solution Flush with DI water
Prewetting
Vent
Drain
創新需求需求再造
Filter Housing
POU typically single 10" filter housing
Materials of construction: PFA, PVDF, PP, SS
創新需求需求再造
Filter Cartridge Housing
T-Line Design In-line DesignInlet
Outlet
Typical Flow Path
Inlet Outlet
創新需求需求再造
Filter Cartridge Housing
T-Line Design In-line DesignInlet
Outlet
Typical Flow Path
Inlet Outlet
創新需求需求再造
T-Line Mounting Considerations
Bowl Down (top of the head points toward ceiling)
Easier to drain upstream side of filter
Air does not get trapped in core
– Liquid remains in core after drain
– 20" can be difficult to mount filters
Inlet Outlet
創新需求需求再造
T-Line Mounting Considerations
Bowl Up (top of the head points towards the floor)
Complete draining of filter core Easy filter installation Recommended configuration for 20"
housings
– Liquid drains from upstream side of filter
– Must vent downstream side of housing
Vent
Drain
創新需求需求再造Reduced Tool Space Required
• A typical tool design requires enough space to lower the bowl below the cartridge for filter changeout.
• With Chemlock, the bowl only needs to be lowered below the head, then the cartridge and bowl can be removed as a single unit.
• Tool Space Savings - Approx. ~ 8 inches!
• 18” in space savings with 20” bowl
創新需求需求再造Typical Disposable Filter
Assembly
Connections : Flartek, Butt Weld, etc.
Vent
Drain
inlet
outlet
Internal Filter Element
創新需求需求再造
Disposables Vs. Housings
Disposables More compact footprint Cleaner
no o-rings/seals no handling of eleme
nt Easier for prewetting Improved safety Higher Temps ( 180C )
Housings Traditional design Flexibility - 4" -
40" Requires O-ring
change Increased
contamination risk Greater material
selection Easier
customization Limited Temp
( ~100C )
創新需求需求再造
Variables Which Effect Retention
Membrane Contaminant Fluid Conditions
Structure- cast- stretched- irradiated
Charge
Pore size & pore size distribution.
Porosity*ThicknessEtc.
REF.<C01>Type:- solvent- acid- base- mixture
Viscosity*
Flow rate/face velocity
Temperature
Pressure: - pulse- differential
創新需求需求再造
Summary Five major filtration mechanism
1.Cake filtration 2.Size exclusion 3.interception 4.adhesion 5.adsorption
Two major filter types Depth filter—Pre filter-dirty process Membrane filter – Final filter-precision filtration
Filter Wetability Hydrophobic membrane – used for solvent
Hydrophilic membrane –Not need to prewet for water base chemical
Filter Retention Defined by pore size and LRV Affected by Pore size distribution and pore size definition