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The Concept of the Basic Liquid. 技術研討資料. 主講人 : 龍仁生. 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 …
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The Concept of the Basic Liquid 技術研討資料 主講人 : 龍仁生
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 Topics
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
Manufacturing Process Stretched Polymeric Membranes e.g. PTFE
Manufacturing Process Cast Polymer Membranes e.g. PVDF
Manufacturing Process Membranes Track Etched e.g. Polycarbonate
"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 filter Membrane Characteristics That is why HA
Permeate Flow Path Inlet Flow Path • Filter "pack" contains membrane, 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. Typical Filtration Devices: Pleated Cartridges
Permeate Fluid Flow Path 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
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
Filtration Retention Mechanisms: Capture by • Sieving / Interception --- • Hard Particle--- Bridge/ Cake effect • Soft –Gel/Micro-bubble Hard Particles Soft Particles
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Capture by Adhesion / Adsorption Retention Mechanisms: • Very small particles in liquids have a negative charge and can be captured by attraction to a positive charge in a filter
過濾在時間的變化 particlel Time 壓差 Time
Hydrophilic: • Wetting smoothly with, water.". • No pre-wetting • Hydrophobic: • Fear of water; • Tending not to combine with water. • Requires pre-wetting. Hydrophobic Vs Hydrophilic
Hydrophobic Hydrophilic < 90? 90? > 90? No contact angle • Contact Angle is the measure of Wettability Hydrophobic Vs Hydrophilic i.e. Low contact angle = Hydrophobic High contact angle = Hydrophilic
What is Dewetting and how can it impact a process? SC1 SC2 H2O2 NH4F Piranha
QuickChange Filters are Non-Dewetting SC1 SC2 H2O2 NH4F Piranha Non-Dewetting Technology
Vent Drain Prewetting • Flow in one direction (prevents air entrapment) • Flow from upstream side into core • 60:40 IPA water solution • Flush with DI water
Filter Housing • POU typically single 10" filter housing • Materials of construction: • PFA, PVDF, PP, SS
Inlet Typical Flow Path Outlet Filter Cartridge Housing T-Line Design In-line Design Inlet Outlet
Inlet Typical Flow Path Outlet Filter Cartridge Housing T-Line Design In-line Design Inlet Outlet
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 T-Line Mounting Considerations Inlet Outlet
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 T-Line Mounting Considerations Vent Drain
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
Vent Drain outlet Typical Disposable Filter Assembly Internal Filter Element inlet Connections : Flartek, Butt Weld, etc.
Disposables Vs. Housings • Housings • Traditional design • Flexibility - 4" - 40" • Requires O-ring change • Increased contamination risk • Greater material selection • Easier customization • Limited Temp ( ~100C ) • Disposables • More compact footprint • Cleaner • no o-rings/seals • no handling of element • Easier for prewetting • Improved safety • Higher Temps ( 180C )
Membrane Contaminant Fluid Conditions Variables Which Effect Retention Structure - cast - stretched - irradiated Charge Pore size & pore size distribution. Porosity* Thickness Etc. REF.<C01> Type: - solvent - acid - base - mixture Viscosity* Flow rate/face velocity Temperature Pressure: - pulse - differential
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 basechemical • Filter Retention Defined by pore size and LRV Affected by Pore size distribution and pore size definition Summary