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Basic filtration info.

  1. PES cartridges are often called "membrane" or "absolute" filters. They have very high efficiencies--over 99.98%.
  2. PP are depth filters. Plate-and-frame is also depth filter.
  3. Lenticular is identical to plate-and-frame except easier and cleaner to setup, but at a much higher cost.
  4. PES are never the first filtration. They always follow PP. Plate-and-frame or lenticular is often used before PP.
  5. Clogging of a filter quickly, after a small volume, simply means a coarser filtration is required. (or perhaps more effective fining or other clarification in the tank).
  6. If a filter clogs, it is working correctly. If a filter does not clog, then it may not be working correctly. Or you can move to a finer filtration.
  7. Increasing pressure is a clear indicator that a filter is becoming clogged.
  8. 30 psi is typically the maximum pressure for filtration of wine/beer/spirits. Many cartridges can withstand higher pressures, but the efficiency of the filters diminish at these higher pressures.
  9. You can backwash PP cartridges. However, backwashing PES presents great risk that the "membrane" becomes separated from the support---thus destroying the filter. This is not a risk with PP.
  10. The human eye can see 40 micron and larger particles. Thus the eye is a very poor instrument for ascertaining what filtration is required and how effective filtration is. Yeast are ~5 micron for example.
  11. The difference between 'clear' and 'brilliant' is the amount of light scatter from small particles. It can be very difficult for the eye to see light scatter through 4" (the diameter of a wine bottle). As a point of reference, smog scatters light. But smog can rarely be detected by the eye thru even 100', but quite easy to see off in the distance.
  12. Sheet filters (plate-and-frame) and PP cartridge do much the same. The greatest difference is simply the volume. Sheet can handle larger volumes. However, PP cartridges have efficiencies of ~90% while sheets are only about ~65% efficient. This is the primary reason why plate-and-frame filtration is nearly always followed by PP if the final filtration is PES.

Absolute vs High Efficiency vs Nominal
In practical terms, Absolute means all particulates below a specified size are removed.
In quantitative terms, most mfgs employ the standard of >99.98% efficiency.

PES cartridges exceed this 99.98% standard.

High Efficiency is typically reserved for filters of >90% efficiency. Our PP filters exceed this 90% standard.

Nominal filters are typically 60-70% efficient. Filter sheets and lenticular filters are nominal filters. 

["Absolute" PP filters?? Some manufacturers refer to high-efficiency PP cartridges as "absolute" or perhaps "semi-absolute". This is misleading because they are not "absolute" at the labeled porosity. For example, our 0.22 micron PP cartridge is 95% efficient (not absolute) for 0.22 micron particles, but 99.98% efficient (which is absolute) for 2.5 micron particles. We reserve the term "absolute" to PES cartridges to avoid confusion, and also to accurately reflect the intended use of the filter--as a final microbial filter.]

Cleaning PES cartridges

General Sterilization/Sanitation Methods

  • Chemical: Peracetic acid, chlorinated alkaline products, bleach, sulfur dioxide, and hydrogen peroxide at typical sanitation concentrations and temperatures.
  • Hot Water: 185°F at 5 psi
  • Autoclave: 250°F for 30 minutes at 2 psi up to 30 cycles
  • In-Line Steam: 250°F for 30 minutes at 2 psi up to 30 cycles

Do NOT backwash (reverse flow) PES filters

Specific Procedures

Procedure 1. This procedure does not involve caustic or acid.
a)Forward flow with cold water for 5 minutes to remove product.
b)Forward flow with hot water (175° F) for 5 minutes.
c)Now recirculate with hot water for 15-30 minutes. Leave hot water in unit overnight.
d)Rinse with hot water for 2 minutes the next morning.
f) Air-dry cartridge and store in open to avoid mold growth. You can store the cartridge in the filter housing, but be sure to open the valves so air can penetrate.
Cleaning solutions should be filtered. Flow rate ~ 4 GPM per 10" cartridge.

 

If Procedure 1 is not effective, this procedure may be used.

Caustic is dangerous. Wear rubber gloves, boots, safety glasses and apron.

Procedure 2. Hot cautic cleaning
a)Forward flow with cold water for 10 minutes to remove product
b)Forward flow with hot caustic solution (140°-150° F) for 30 minutes. (1% NaOH). This is recirculation but discard the first gallon or so.
c)Forward flow (recirculate) with acid solution for 5 minutes. Any weak acid is suitable including vinegar.
d)Forward flow with cold water for 30 minutes. Do not recirculate in this step. You must be certain that all caustic and acid is removed.
f) Air-dry cartridge and store in open to avoid mold growth. You can store the cartridge in the filter housing, but be sure to open the valves so air can penetrate.

Cleaning solutions should be filtered.
Flow rate should be 4 GPM/10" cartridge for hot caustic. 4-10 GPM/10" cartridge for cold water and acid solution.

Procedure 3. Alternative cleaning procedure using cold caustic:

a)Forward flow with cold water for 10 minutes to remove product
b)Soak overnight--up to 12 hours-- in caustic solution (1% NaOH)
c)Soak in acid solution for one hour (any weak acid including vinegar)
d)Forward flow with cold water for 30 minutes. Do not recirculate. You must be certain to remove all caustic and acid.
f) Air-dry cartridge and store in open to avoid mold growth. You can store the cartridge in the filter housing, but be sure to open the valves so air can penetrate.

Cleaning solutions should be filtered.
Flow rates should be 4-10 GPM/10" cartridge.

Cleaning PP cartridges

The cleaning procedure for PP cartridges is the same except you can reverse flow through PP cartridges. Be careful not to exceed the maximum pressure for reverse flow.

 Inserting Filter Cartridges
Lubricate the orings before inserting into housing. Food grade silicone spray or even water will work well.

 

Cartridge Filters vs Filter Sheets and Modules

Depth vs Membrane Filtration (Volume Filters vs Surface Filters)

Generally, depth filtration (sheet filter or lenticular module) is used to remove the vast majority of particulates. ABSOLUTE PES membrane cartridges are used just before bottling to ensure yeast (but not bacteria) removal. PP pleated cartridge filters are used ahead of PES to protect them from being overloaded. Also, PP cartridges are used in place of sheets  and modules for smaller volumes.

Absolute PES Cartridge Filters are Membrane Filters. Membrane filters are used as a final step to ensure microbial stability.

  • PES 0.45 micron will remove all yeast but not bacteria for wine and beer.

Membrane Filters are Surface Filters. In the simplest form, they are a thin layer of material (PES) with well defined and uniform hole sizes. Particulates smaller than the hole size pass through, anything larger than the hole size gets stopped on the surface of the membrane.

  • >99.999% Efficiency (Absolute)

High Efficiency PP Pleated Cartridge Filters have both depth and membrane filtration features.

  • >95% Efficiency
  • Large Surface Area.
  • Surface Area of 10" Cartridge filter is typically 0.6 m2. (for comparison, this is equal to the surface area of ~5 40x40 sheets).