Inline Fans

Inline fan, hose and shroud have to share the same nominal size. The conversion: 4 inch = 100 mm, 6 inch = 150 mm, 8 inch = 200 mm, 10 inch = 250 mm. The fans with switch, thermostat and run-on timer are available in all four sizes, the axial inline fan with speed controller in 100 to 200 mm (4 to 8 inch).

Your fan shroud sets the size — running an 8 inch shroud means an 8 inch fan and an 8 inch hose. Reducing the diameter mid-run adds resistance and costs airflow.

All four move air through a round duct; they differ in how they are controlled:

• Two-speed with switch — two fixed power levels selected on the switch. The simplest option once you have found your operating point.
• Temperature speed control — built-in electronic speed controller with thermostat, regulating on its own by the air temperature inside the duct.
• Run-on timer — keeps running for 2 to 30 minutes after switch-off, adjustable on the dial of the control unit.
• Axial with speed controller — steplessly adjustable directly on the power cable, with a 230 V plug and a mounting base for wall or ceiling.

The first three are inline duct fans in a plastic housing with a ball-bearing motor (service life up to 40,000 hours, overheating protection with automatic reset, protection class IPX4). The axial fan is a black plastic unit with an AC motor and protection class IP44.

The inline fan with temperature speed control has a thermostat in its control unit. You set a temperature target plus the lower continuous speed. If the air temperature in the duct rises 2 °C above the target, the fan switches to full speed; once it drops below the target again, it returns to the lower speed you set.

That matches how mining load changes: with the miner throttled or idle, the low step is enough and things stay quiet. When waste heat picks up, the fan ramps up by itself. If you would rather turn a dial yourself, take the axial inline fan with stepless control.

The fans with switch, thermostat and run-on timer deliver 245 to 1400 m³/h depending on nominal size. The axial inline fan reaches 322 to 900 m³/h at a static pressure of 160 to 380 Pa. A larger nominal size means more volume — which is why 10 inch is the usual choice when a miner at full load has to push all its waste heat through one run.

On length: the units are designed for duct systems of up to 8 to 10 metres. Every bend and every metre adds resistance, so the short, straight run is always the more efficient one. If pressure falls short, several inline fans can be installed in series in the same run — that raises the pressure build-up and with it the volume of air transported.

Either works; the fan can sit anywhere in the duct system, vertically or horizontally. On the exhaust side it pulls warm air out of the shroud and pushes it to the window, the wall outlet or the room you want to heat. On the intake side it brings cool outside air to the miner.

If you remove the miner's original fans and switch fully to external cooling, you also need a fan spoofer, otherwise the miner reports a fan error. The fan is built for clean air: in dusty environments put a dust filter in front of it, or the impeller will clog up.

An inline fan is the quieter part of the setup — what stays loud is usually the miner itself. The most effective lever is speed: if you do not need the full airflow, turn it down and the noise drops noticeably. The axial fan does this steplessly on the power cable, the thermostat model automatically via the target value, the others through the second power step.

Two more things help: an insulated ducting hose absorbs sound along the run, and tight joints prevent hissing at the transitions. Audible vibration usually comes from rigid mounting — better to let the flexible hose carry the fan than to couple it hard to the wall.

The fan is spliced into the run: hose from the fan shroud over one port, a second hose over the other. Fix both connections with a hose clamp and seal them with aluminium tape where needed. The units work with rigid and flexible ducting alike.

A practical detail is that the inline fans come apart: you can fit the housing into the run first and insert the turbine unit later — release the locking screws, open the tension bands, take out the turbine, almost without tools. The same applies to maintenance, without dismantling the duct system again. The axial fan is screwed to a wall or ceiling by its base and connected via a 230 V plug; the run-on timer model requires electrical knowledge for wiring.