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Kl Series Desiccant Breathers

DES-CASE KL Series Desiccant Breathers: How Steel Standpipe Design Handles Vibration and Harsh Environments

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What Are DES-CASE KL Series Desiccant Breathers and Who Are They For?

The DES-CASE KL Series desiccant breathers are steel-standpipe-based contamination control devices engineered for vibration-prone and harsh operating environments. Unlike plastic-housing breathers, the steel standpipe construction provides structural durability, making the KL Series well-suited for mobile and off-road equipment, truck differentials, nautical applications, and heavy industrial settings including mining, wind energy, pulp and paper, petrochemical, and aviation.

The series is offered in three volumetric sizes — 93 (320 cc), 96 (600 cc), and 121 (1040 cc) — and can be ordered with or without check valves, giving maintenance engineers flexibility across a wide range of airflow and reservoir-size requirements.

How Does the KL Series Filter Airborne Contamination?

The KL Series achieves 3 µm absolute filtration efficiency, rated at β₃ ≥ 200, using a glass fiber filter media. This rating means that for every 200 particles at 3 µm entering the filter, fewer than one passes through — a critical performance threshold for hydraulic systems operating under ISO cleanliness targets.

All components outside the check valves are constructed from copolyester, Buna-N, stainless steel, galvanized steel, and aluminum (check-valve models). Check valves are silicone and crack at just 0.05 psi (0.003 bar), allowing airflow with minimal restriction. The breather is chemically compatible with all mineral oils, most synthetic oils, and diesel fuels; contact DES-CASE technical support for other fluid compatibility inquiries.

How Does ZR Gel Adsorption Prevent Moisture Ingression?

The drying agent in every KL Series breather is ZR Gel, a 3–6 mm granular desiccant. ZR Gel is a color-indicating material: it transitions from red to yellow as it becomes saturated, giving technicians a clear visual cue for service intervals without disassembly.

Water adsorption capacity scales with breather size:

  • KL 93: 3 fl. oz (94 ml) maximum water retention, 0.6 lbs (250 g) desiccant
  • KL 96: 5.5 fl. oz (172 ml) maximum water retention, 1 lb (460 g) desiccant
  • KL 121: 10 fl. oz (300 ml) maximum water retention, 1.8 lbs (800 g) desiccant

All three sizes operate across the same temperature range: -40°F to 194°F (-40°C to 90°C), making them viable for both cold-start mobile equipment and heated industrial reservoirs.

What Airflow Capacity Does Each KL Series Size Support?

Airflow capacity determines which breather size matches a given reservoir’s breathing rate. Without check valves, the KL 93 and KL 96 each handle up to 25 cfm (700 l/min), while the KL 121 scales to 53 cfm (1500 l/min). When check valves are fitted, maximum airflow is reduced: KL 93 and KL 96 are rated at 11 cfm (300 l/min) each, and the KL 121 at 14 cfm (400 l/min).

DES-CASE notes that these figures are general sizing guidelines only. Humidity level, frequency of airflow, ambient temperatures, and chemical compatibility all factor into proper breather selection. For larger applications or special circumstances, DES-CASE recommends direct technical consultation.

What Are the KL Series Mounting Dimensions and Thread Specifications?

Physical sizing is relevant when retrofitting an existing breather port or designing a new installation:

  • KL 93: 3.9 in (98 mm) diameter, 7.1 in (180 mm) height, ¾” BSPP male thread
  • KL 96: 3.9 in (98 mm) diameter, 9.4 in (240 mm) height, ¾” BSPP male thread
  • KL 121: 5.1 in (130 mm) diameter, 11 in (280 mm) height, 1¼” BSPP male thread

The KL 93 and 96 share the same footprint and thread, simplifying upgrades from a smaller to a larger desiccant volume without repiping.

How Are KL Series Breathers Serviced and What Spare Parts Are Available?

The KL Series is designed for field serviceability. Spare parts are available by size and include spin-on cartridges, ZR Gel refills, and complete spare kits. Each spare kit (RK-93, RK-96, or RK-121) contains one KL Spin-On cartridge, one ZR Gel refill, two foam filters, one bottom seal sticker set, and one adapter plug — everything needed for a full in-field service.

  • Spin-On (93/96): KL90 (P/N 9331034)
  • Spin-On (121): KL120 (P/N 9317903)
  • ZR Gel refill 93: RF-300 (P/N 9331156)
  • ZR Gel refill 96: RF-600 (P/N 9331155)
  • ZR Gel refill 121: RF-1000 (P/N 9331157)
  • Spare Kit 93: RK-93 (P/N 9318115)
  • Spare Kit 96: RK-96 (P/N 9318116)
  • Spare Kit 121: RK-121 (P/N 9318117)

Summary

  • DES-CASE KL Series breathers use a steel standpipe for vibration resistance and are available in 320 cc, 600 cc, and 1040 cc sizes.
  • Filtration is 3 µm absolute (β₃ ≥ 200) via glass fiber media; desiccant is ZR Gel with red-to-yellow color indication.
  • Temperature range is -40°F to 194°F (-40°C to 90°C); compatible with mineral oils, most synthetics, and diesel fuels.
  • Check-valve cracking pressure is 0.05 psi (0.003 bar); airflow without check valves reaches 53 cfm (1500 l/min) on the KL 121.
  • Complete spare kits (RK-93, RK-96, RK-121) support full field serviceability with spin-on cartridge, ZR Gel refill, foam filters, seal stickers, and adapter plug.

Step-by-step

  1. Select the KL Series size (93, 96, or 121) based on reservoir breathing rate, desiccant volume requirement, and available mounting space.
  2. Specify the order code: choose drying agent code R (ZR Gel) and check valve option V (with) or – (without) based on airflow and backpressure requirements.
  3. Verify chemical compatibility with the fluid in service; contact DES-CASE technical support if using fluids other than mineral oil, common synthetics, or diesel.
  4. Install using the correct BSPP male thread: ¾” for KL 93/96, 1¼” for KL 121.
  5. Monitor the ZR Gel color indicator — replace or service when color transitions from red to yellow.
  6. Use the appropriate spare kit (RK-93, RK-96, or RK-121) for field service, including spin-on cartridge, ZR Gel refill, foam filters, seal stickers, and adapter plug.

Products discussed in this episode

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