DES-CASE Rebuildable Steel Breathers: How to Size and Rebuild RS-Series for Bulk Storage - PE Energy

What are DES-CASE Rebuildable Steel Breathers and where are they used?

DES-CASE Rebuildable Steel Breathers (RS-Series) are heavy-duty desiccant breathers engineered for extreme environments, bulk storage tanks, and large circulating lube oil systems. The rugged steel housing sets them apart from standard plastic-bodied breathers, making them suitable for power generation, pulp and paper, steel manufacturing, chemical and harsh environments, hydraulic reservoirs, and diesel tank storage.

Models range from DC-RS-3 (3 lbs desiccant) up to DC-RS-200 (200 lbs desiccant), with thread connections scaling from 2″ NPT on smaller units to 4″ NPT on the largest. This breadth of sizing means a single product family can serve both a small hydraulic reservoir and a large industrial bulk storage installation.

How do DES-CASE RS-Series breathers filter and adsorb moisture?

Each RS-Series unit combines two protection mechanisms: a pleated microglass filter element rated at 1 µm absolute for particle removal, and a desiccant media — standard silica gel — that adsorbs water vapor from incoming air. The operating temperature range is -20°F to 220°F (-29°C to 104°C).

Water adsorption capacity scales directly with desiccant load. Key reference points from the spec sheet:

DC-RS-3 (3 lbs / 1.4 kg desiccant): 0.14 gal (0.5 L)
DC-RS-25 (25 lbs / 11 kg): 1.2 gal (4.5 L)
DC-RS-100 (100 lbs / 45 kg): 4.8 gal (18 L)
DC-RS-200 (200 lbs / 91 kg): 9.5 gal (36 L)

The sight glass indicator provides a clear visual cue: silica gel changes color from blue to pink when the unit requires rebuilding, eliminating guesswork during routine inspections.

How do you size a DES-CASE RS-Series breather for your application?

Maximum airflow is the primary sizing parameter. DES-CASE publishes application sizing guidelines for each model, though the manufacturer notes that humidity level, frequency of airflow, ambient temperatures, and chemical compatibility must all be considered. Larger and special-circumstance applications require the most thorough analysis; DES-CASE technical support is available for assistance.

Representative airflow ratings from the spec sheet:

DC-RS-3 and DC-RS-5: 85 cfm (2,407 L/min)
DC-RS-15: 205 cfm (5,805 L/min)
DC-RS-100: 270 cfm (7,645 L/min)
DC-RS-150: 250 cfm (7,079 L/min)
DC-RS-200: 240 cfm (6,796 L/min)

Note that airflow capacity is not strictly linear with desiccant volume — the DC-RS-100 actually has the highest rated airflow at 270 cfm. Thread diameter increases with unit size: 2″ NPT for RS-3 through RS-9, 3″ NPT for RS-15 through RS-75, and 4″ NPT for RS-100 through RS-200.

What customization options are available for DES-CASE RS-Series housings?

The RS-Series supports a broad customization matrix to match chemical compatibility requirements. Steel housing options include carbon steel (standard), 304 stainless steel, and 316 stainless steel. Gasket and seal materials include Buna-N (standard), Viton®, EPDM, and SBR Rubber.

Desiccant media options go beyond standard silica gel: activated carbon, molecular sieve, and activated alumina are available. Filter media alternatives include polyurethane filter and plastisol filter in addition to the standard microglass element. The units are compatible with all mineral oils, most synthetic oils, and diesel fuels; for other chemicals, DES-CASE recommends contacting their technical support team.

How do you rebuild a DES-CASE RS-Series breather?

The rebuildable design is the defining feature of the RS-Series — rather than discarding the entire unit, maintenance technicians replace internal components using factory-supplied rebuild kits. Each unit’s desiccant bag is made from polypropylene with handles for easy removal and replacement. Desiccant bags for units above RS-25 are packaged in 25 lb increments for handling convenience.

Rebuild parts and accessories use a standardized part-code structure: replace the “X” in the part code with the appropriate RS model number. For example, the sight glass cartridge for a DC-RS-150 is ordered as DC-RS-150-SG1.

Available rebuild components:

DC-RS-X-RK: Complete Rebuildable Steel Breather Kits
DC-RS-X-F1: Microglass Filter Elements
DC-RS-X-D1: Desiccant Bag Sets
DC-RS-X-SG1: Sight Glass Cartridges
DC-RS-X-P1: Foam Pad Inserts
DC-RS-X-G1: Gasket Seals

DES-CASE also recommends installing a pressure/relief valve on any tank or storage system where these breathers are used.

Summary

DES-CASE RS-Series breathers filter to 1 µm absolute and operate from -20°F to 220°F (-29°C to 104°C).
Ten models (RS-3 through RS-200) hold 3–200 lbs of desiccant with water adsorption capacities from 0.14 gal to 9.5 gal.
Maximum airflow ratings range from 80 cfm to 270 cfm depending on model; sizing must also account for humidity, airflow frequency, and ambient temperature.
Housing, seal, desiccant media, and filter media are all customizable; compatible with mineral oils, most synthetics, and diesel fuels.
On-site rebuilding via standardized part kits (RK, F1, D1, SG1, P1, G1) extends service life without replacing the steel housing.

Step-by-step

Select the RS-Series model based on maximum airflow (cfm), desiccant capacity (lbs), and thread size (2″, 3″, or 4″ NPT) required for your tank or system.
Specify housing material (carbon steel, 304 SS, or 316 SS), seal material, and desiccant media type to match chemical compatibility requirements.
Install the breather on the tank or reservoir and fit a pressure/relief valve as recommended by DES-CASE.
Inspect the sight glass indicator regularly — blue silica gel is active; a color change to pink signals that rebuilding is required.
Remove the desiccant bag using its polypropylene handles and replace with a new desiccant bag set (DC-RS-X-D1).
Replace the microglass filter element (DC-RS-X-F1) and any worn gasket seals (DC-RS-X-G1) during each rebuild cycle.

Products discussed in this episode

Browse all DES-CASE products on PE Energy Industrial Supply.

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