System & Maintenance · DWG LS-013

Desiccant breather sizing calculator

Thermal-expansion and rapid-draw CFM models with port-adequacy checks, ranked against Des-Case, Guardian and TTI desiccant and particle breathers. Donaldson (Hy-Pro) is listed for its T.R.A.P. and particle units; it has no desiccant units in the data.

LubeSuite methodLast reviewed 4 Oct 2026

Source: Des-Case standard breathers data sheet (PDF)

The air-flow (CFM) models and estimated desiccant life (desiccant capacity ÷ moisture load) are LubeSuite estimates; breather capacities come from maker data (Des-Case, Donaldson, Guardian, TTI).

Breather Sizing Calculator

Reservoir · fill / headspace

Breather Type

Desiccant: silica gel dries the incoming air and a filter stops particles — sized by flow, replaced when the gel is spent (Est. Life).

Application Type

Total Reservoir / Tank Volume

Used to calculate headspace and validate that fluid level swing is physically possible.

Typical Fill Level Headspace = total volume × (1 − fill level).

Headspace Volume (air space above fluid)

Headspace Estimator — Box / Rectangular

Length (in)

Width (in)

Air height (in)

Measure the empty air space above the oil line. Result fills the headspace field above in gallons.

Temperature Swing — Cold Start → Operating

→

Use ambient low for cold, max operating temp for hot.

Max Fluid Level Swing (actuator stroke / pump demand)

Volume displaced when actuators extend / fluid is pumped out. The calculator will flag if this exceeds available headspace.

Rapid Draw Rate (optional — overrides 30-min warmup model)

Use when fluid is rapidly displaced by actuators or a pump cycle — e.g. 200 gal in 1.5 min. This computes instantaneous peak CFM directly from flow rate, which is more accurate than the thermal model for fast-draw applications.

Ambient Relative Humidity

Operating Hours / Day

Supplier

All shown by default — click to toggle a supplier off.

Desired Change Interval (optional — filters by Est. Life)

Shows desiccant breathers whose estimated life is at or above this interval (1 mo = 30 days, as in the Est. Life column). T.R.A.P. and particle-only breathers are changed by ΔP indicator, so when they're selected under Breather Type they're listed separately.

Existing Breather Port Size (optional — to check adequacy) If selected, the tool will flag if this port is undersized for the required CFM.