Technical resources

A multi-vane rotor turns inside a close-clearance housing. Material falls into the pocket at the inlet, is carried round as the rotor turns, and discharges at the outlet. Because the rotor tip runs close to the housing bore, the valve restricts air flow between the two zones while still passing solids.

The hardware is the same; the emphasis differs. 'Rotary feeder' usually implies a metering duty where the rotation speed controls the rate. 'Rotary airlock valve' usually implies a sealing duty where the priority is limiting air leakage. Most applications need some of both, and the specification should say which matters more.

Clearance is a trade-off between leakage and the risk of metal-to-metal contact as the valve heats up. Tighter clearance seals better but needs better machining, better bearings and a material that will not swell or gall. We set it from the differential pressure, the particle size and the temperature.

Usually one of three reasons: the clearance has opened through wear, the rotor is running faster than the dust can fill the pocket (so air passes through an empty pocket), or the pressure difference is higher than the valve was specified for. Measuring the actual differential pressure is the first step.

Not by default. A standard rotary airlock valve is not a certified explosion isolation valve. If your installation requires explosion protection, the hazardous zone, the equipment design and the applicable regulations must be assessed separately, and any claim of compliance has to be backed by certification we would need to hold for that specific product.

Measure the face-to-face length, the flange outside dimensions and bolt circle, the bolt hole diameter and count, the shaft diameter and keyway, and the mounting position of the drive. A photograph with a rule in frame helps. With those we can normally build a drop-in unit.

Material and bulk density, required capacity in kg/h or m³/h, operating temperature, the pressure or vacuum at the valve, the particle size range, and the drive voltage and protection class for your market. Drawings remove most of the remaining uncertainty.

Often, yes — if we can measure or obtain the critical dimensions. Send photographs and dimensions and we will confirm what we can supply, and say clearly where a match is not possible.