HVAC — capture filter loading and volume flow mechanically

Filters age, dampers drift, volume flows shift. A ring balance delivers the current differential pressure over weeks, months, and years — no drift, no readjustment required, directly usable for replacement intervals, volume flow control, and filter diagnostics.

Typical installation points

Before and after filter stages (G4, F7, F9, HEPA H13/H14)
Across dampers and volume flow controllers
Between supply and exhaust ducts
In stairwells for smoke-control overpressure (pressure ventilation)
In control cabinets to monitor filter mats

Why a ring balance fits here

HVAC is less about peak accuracy and more about long-term stability. An electronic pressure sensor in a ventilation duct is stressed by vibration, temperature swings, and humidity — drift, zero-point shift, and sensor failures follow. The ring balance is a passive mechanical measuring element: no diaphragm or spring under pressure load, no components that age or fatigue.

Filter monitoring

When pressure drop rises above a threshold, a contact switches or the 4–20 mA signal triggers a filter-change alarm.

Volume flow measurement

Combined with an orifice plate, a ring balance converts differential pressure directly into a volume flow display — square-root scale available on request.

Stairwell overpressure

Intrinsically safe variant (RW65_EX_II) for combustible environments, ATEX-certified.

Long-term stability

No drift from vibration or temperature cycles — the measuring element does not age.

Steady signal at small spans

In the typical filter monitoring range (50–250 Pa) the mechanical inertia of the ring body acts as a low-pass filter — pressure fluctuations from fan start-up or duct turbulence are physically damped. No nervous output signal, no damping parameters in the controller that can be misconfigured. At larger spans (>600 Pa) the restoring force of the calibration weight dominates and response time shortens accordingly.