# String Wound Cartridge (VAREN)

> Fil-Trek Cartridge Filters. Canonical page: https://www.fil-trek.com/products/cartridge-filters/varen

Category: Cartridge Filters
Series: VAREN
Model format: `VS-[MEDIA]-[MICRON]-[OD]-[LENGTH]-[CORE]-[END CAP]-[SEAL]`
Example: `VS-PO-5-D1-20-PO-E4-BN`

## Overview
String-wound depth cartridge for rugged particulate reduction across water, chemical, and utility process streams

## How It Works
Fluid flows outside-in through a tightly wound depth matrix; coarse outer layers capture larger particles while inner layers retain finer debris

## Applications
- General plant/process water and well/desal intake sand & silt removal
- Chemical/batch prefiltration and coatings/inks guard service
- Cooling, boiler makeup, and utility line protection at 0.5–100 µm
- Data centers: TCS CDU filtration, FWS cooling tower, chilled water filtration

## Physical Specifications
- **flow direction:** Outside-to-inside
- **backwash-able:** No
- **outside diameter options:** 2.5", 4.5"
- **inner diameter options:** 1.0"
- **nominal length options:** 10", 20", 30", 40"
- **end cap options:** DOE W/ Cut Ends, DOE W/ Extended Core, SOE W/ 222, 222/Fin Single Open End, SOE W/ 226, 226/Fin Single Open End, SOE W/ Plastic Spring & 222, Pre-Attached Spring (one end only)
- **caps materials:** Polypropylene, Tinned Steel, Stainless 304, Stainless 316
- **cores materials:** Polypropylene, Tinned Steel, Stainless 304, Stainless 316
- **gasket material options:** Buna-N, EPDM, Silicone, Viton, Teflon encap. Viton

## Media Specifications
- **media primary options:** Polypropylene, Polyester, Cotton, Rayon, Acrylic, Nylon, Fiberglass
- **micron ratings:** 0.5, 1, 3, 5, 10, 20, 50, 100
- **efficiency percent:** 90%
- **media rating:** Nominal
- **beta ratio:** 10
- **changeout dp:** 35 PSID
- **burst pressure:** 75 PSID
- **max temperature:** 200°F (Polypropylene), 350°F (Polyester), 300°F (Bleached Cotton, Rayon, Nylon), 750°F (Acrylic, Fiberglass)
- **approvals certifications:** FDA Listed, NSF 61

## Housing Compatibility
- Standard cartridge filter housings

## Ordering
- Model format: `VS-[MEDIA]-[MICRON]-[OD]-[LENGTH]-[CORE]-[END CAP]-[SEAL]`
- Example: `VS-PO-5-D1-20-PO-E4-BN`

### Od codes
- **D1:** 2.5"
- **D6:** 4.5"

### Length codes
- **STD:** See Table

### Media codes
- **PO:** Polypropylene
- **PF:** FDA Polypropylene
- **PN:** NSF 61 Polypropylene
- **PE:** Polyester
- **CO:** Bleached Cotton
- **RA:** Rayon
- **AC:** Acrylic
- **NY:** Nylon
- **FG:** Fiberglass

### Seal codes
- **Blank:** None (E1 only)
- **BN:** Buna-N
- **EP:** EPDM
- **SI:** Silicone
- **VI:** Viton
- **TEV:** Teflon encap. Viton

### Core codes
- **PO:** Polypropylene
- **TN:** Tinned Steel
- **S4:** Stainless 304
- **S6:** Stainless 316

### Cap codes
- **E1:** DOE W/ Cut Ends
- **E3:** DOE W/ Extended Core
- **E4:** 222/Flat Single Open End
- **E5:** 222/Fin Single Open End
- **E6:** 226/Flat Single Open End
- **E7:** 226/Fin Single Open End
- **E8:** SOE W/ Plastic Spring & 222
- **E9:** Pre-Attached Spring (one end only)

### Size codes
- **10:** OD 2.5, 4.5", ID 1", length 10"
- **20:** OD 2.5, 4.5", ID 1", length 20"
- **30:** OD 2.5", ID 1", length 30"
- **40:** OD 2.5", ID 1", length 40"

### Micron ratings
- 0.5, 1, 3, 5, 10, 20, 50, 100

## Contact
- **sales@fil-trek.com** — all filtration product inquiries, projects, filter housings, and filtration systems
- **filters@fil-trek.com** — replacement filter media, filter elements, filter bags, hardware, and spare parts

## Links
- HTML: https://www.fil-trek.com/products/cartridge-filters/varen
- Markdown: https://www.fil-trek.com/products/cartridge-filters/varen.md