Distributed by Purecowater, the ErtelAlsop Pak® Lenticular Filters represent the gold standard in depth filtration technology. Designed to replace traditional plate and frame filters, these lenticular modules provide a totally enclosed, leak-free environment that ensures product integrity and operator safety. Whether for pharmaceutical applications, food and beverage processing, or industrial chemical filtration, the Pak® series offers a versatile and scalable solution for high-efficiency solid-liquid separation.
What is a Lenticular Pak® Filter?
The concept of the lenticular filter module was originally invented by Alsop Engineering (now ErtelAlsop) in the 1940s. A “Pak” consists of stacked lenticular filter cells, ranging from 5 to 18 cells per module. Each cell acts as a double convex lens—hence the term “lenticular”—comprised of two depth filter sheets sealed by a patented polypropylene edge process.
This design combines the superior retention capabilities of depth filter media with the ease of use of a cartridge format. The result is a system that handles high solids loading while providing a wide range of particle retention, typically from 0.25 to 15 microns.

Key Features and Benefits
1. Enclosed Design for Safety and Hygiene
Unlike open plate and frame presses, the Pak® lenticular cartridges operate within a sealed housing. This eliminates leakage and exposure to the atmosphere, making them ideal for:
- Pharmaceuticals: Preventing contamination and ensuring sterility (Bio-Pak® grade).
- Volatile Chemicals: Protecting operators from fumes (using horizontal or vertical housings).
- Distilled Spirits: Preventing alcohol loss through evaporation/leakage.
2. High Solids Loading and Efficiency
The complex matrix of fibers and filter aids (such as Diatomaceous Earth or Perlite) within the media creates a tortuous path for fluid. This depth filtration mechanism traps particles not just on the surface, but throughout the thickness of the media, allowing for significantly higher dirt-holding capacity compared to pleated membrane cartridges.
3. Versatile Configurations
Modules are available in standard 12-inch (30.5 cm) and 16-inch (40.6 cm) diameters. They feature industry-standard end-cap configurations, ensuring compatibility with most existing lenticular housings on the market.
Product Specifications
Below are the general technical specifications for the ErtelAlsop Pak® series available through Purecowater.
| Feature | Specification Details |
|---|---|
| Diameters | 12″ (30.5 cm) and 16″ (40.6 cm) |
| Number of Cells | 5 to 18 stacked cells per module |
| Micron Ratings | 0.25 µm to 15 µm (Nominal) |
| End Configurations | Flat Gasket, Double O-Ring |
| Core Material | Polypropylene |
| Gasket Material | EPDM (Standard), Buna-N, Viton, Silicone available |
| Sterilization | Steam-in-place (SIP) or Hot Water Sanitization |
Media Options Breakdown
Selecting the right media is crucial for optimizing your filtration process. Purecowater can assist in determining the best media grade for your specific application.
| Media Series | Composition | Ideal Applications |
|---|---|---|
| MicroMedia® (Zeta-Pak) | Cellulose & Diatomaceous Earth (DE) / Perlite + Resin | Haze removal, botanical extracts, general clarification. High Zeta potential. |
| AlphaMedia® (Disc-Pak) | 100% Cellulose | Dielectric oils, perfumes, syrups. Used where DE is not permitted. |
| MicroClear® | Carbon-impregnated Cellulose | Color correction, odor removal, decolorization of spirits or chemicals. |
| Bio-Pak® | Pharmaceutical Grade Media | Critical pharmaceutical and biological applications. Low endotoxins. |
Common Applications
The ErtelAlsop Pak® filters are highly versatile and are currently deployed in a wide array of industries:
- Chemicals: Removal of carbon haze, catalyst recovery, and polishing of bulk chemicals.
- Food & Beverage: Filtration of sugar syrups, soft drinks, beer, wine, and distilled spirits.
- Botanical Extracts: Efficient removal of waxes and lipids (dewaxing) in cannabis or hemp oil processing using MicroMedia® XL series.
- Cosmetics: Clarification of perfumes, colognes, and lotions.
- Utilities: Filtration of transformer oils and dielectric fluids.
Why Partner with Purecowater?
As a distributor and OEM for top-tier filtration engineers, Purecowater provides more than just products; we provide solutions. We can help integrate ErtelAlsop Pak® cartridges into your existing system or design a custom housing and skid solution tailored to your flow rates and retention requirements.
For guidance on selecting the right micron rating, media type, and housing configuration for your unique process: