For industries requiring high-capacity solids retention and superior filtrate clarity, ErtelAlsop Pak® Lenticular Filters offer a proven, scalable solution. Distributed by Purecowater, these depth filter modules combine the filtration efficiency of traditional plate and frame filter presses with the convenience and sanitary benefits of a contained cartridge system.
Whether you are processing botanical extracts, pharmaceuticals, food and beverages, or industrial oils, the ErtelAlsop Pak line—including the Zeta-Pak® and Disc-Pak®—provides versatile options to meet stringent purity standards.

What is a Lenticular Filter?
A lenticular filter consists of depth filter media sheets comprised of cellulose, diatomaceous earth (DE), perlite, or other filter aids, sealed into disc-shaped cells. These cells are stacked and bonded to a central core to form a robust cartridge.
Unlike surface filtration, which traps particles only on the top layer, depth filtration captures contaminants throughout the thickness of the media matrix. ThisTortuous path” structure allows for high solids loading capacity and the retention of haze, waxes, and ultra-fine particles.
According to clearsolutionscorp.com, the advantages of this design include:
- Enclosed System: Prevents product leakage and exposure to the atmosphere (ideal for volatile solvents or sanitary applications).
- High Surface Area: A compact footprint delivers high flow rates.
- Rapid Changeout: Modules can be replaced in minutes compared to the hours required for cleaning filter presses.

Product Series Overview
ErtelAlsop manufactures distinct series of lenticular filters to suit specific chemical compatibility and filtration goals.
1. Zeta-Pak® (MicroMedia®)
The Zeta-Pak® is the industry standard for depth filtration requiring high retention efficiency. It utilizes MicroMedia®, a formulation integrated with filter aids (such as DE or Perlite) and wet strength resins. These filters exhibit a positive Zeta Potential, which electrokinetically attracts negatively charged contaminants like bacteria and endotoxins, enhancing removal efficiency beyond simple mechanical straining [store.ertelalsop.com].
Common Applications:
- Botanical extract dewaxing (removal of lipids/waxes).
- Haze removal in spirits and wines.
- Bio-pharmaceutical clarification.
2. Disc-Pak® (AlphaMedia™)
The Disc-Pak® utilizes AlphaMedia™, which is 100% pure cellulose. It contains no resins, binders, or inorganic filter aids like DE. This makes it ideal for applications where imparting taste or odor is a concern, or where silica (DE) is prohibited.
Common Applications:
- Dielectric oils.
- Fragrances and perfumes.
- Light to medium viscosity liquids.
- Coolants and lubricating oils.
Technical Specifications
Purecowater supplies ErtelAlsop filters in standard industry configurations to fit existing lenticular housings. Below is a comparison of the typical specifications.
| Feature | Zeta-Pak® Specs | Disc-Pak® Specs |
|---|---|---|
| Media Type | Cellulose, Filter Aid (DE/Perlite), Resin | 100% Cellulose (No inorganic aid) |
| Micron Ratings | 0.25 to 15 Micron | 1, 5, 10 Micron |
| Dimensions | 12″ and 16″ Diameter | 12″ and 16″ Diameter |
| Cell Count | Typically 5 to 16 cells per module | Typically 5 to 16 cells per module |
| End Cap Config | Flat Gasket (DOE) or Double O-Ring | Flat Gasket (DOE) or Double O-Ring |
| Core Material | Polypropylene (Standard) | Polypropylene |
| Max Temp | ~180°F (depending on gasket/polymer) | ~180°F |
Why Choose ErtelAlsop Lenticulars?
Scalability and Modularity
Lenticular housings can be vertically scaled. A housing designed for 4-high stacking can run with 1, 2, 3, or 4 modules depending on batch size, without changing the footprint. This allows facilities to start small and expand capacity easily [membrane-solutions.com].
Superior Contaminant Retention
When removing deformable particles or gelatinous solids, depth media excels where pleated membrane cartridges might foul instantly. The thick matrix allows the filter to hold significantly more solids before reaching terminal differential pressure.
Configurations for Every Housing
ErtelAlsop Paks are available in two primary sealing mechanisms:
- Flat Gasket (DOE): Requires a tightening post; common in legacy beverage housings.
- Double O-Ring (Plugin): Plugs directly into the receiver plate for a secure, bypass-free seal; easier to install and remove.
Contact Purecowater for Sizing and Availability
Selecting the correct grade of depth media for your specific fluid—whether for stripping color with carbon-impregnated media or polishing oil—is critical to process economics.
Purecowater can assist in determining the optimal micron rating, media formulation, and gasket compatibility for your operation.