Huky 500 – Measuring Air Flow

Huky 500 is an ingenious hobbyist roaster; especially how air flow is managed. The original design utilized one fan for drum ventilation and bean cooling;  placed directly under the bean dump door. Much later the detachable vent pipe was extended to allow fan placement on the side of the roaster; making the last stage easier to manage.

The damper inside the vent pipe is very well made, fits snug, but small in size. That makes adjustments difficult but usable. Another option for drum air control is fan speed control with either a variac or sliding light dimmer.

Lets look at measuring Huky 500 air flow with an inexpensive anemometer available on Ebay for @ 10$. Two ways to accomplish this are with the vent pipe attached sitting on the fan assembly (roaster end open) or directly on the fan/funnel assembly.

(Damper is open during fan speed measurements)

Wide open fan speed ran @ 15 m/s (meters per second). Let say this is the 100% and fan off is 0%. The sliding controller has a low detent; this is the first logical measuring point.

2.5 m/s gives @ 16% air.

Next up is the approximate 1/2 way point; 7 m/s. 47% of total.

Finally the approximate 3/4 point; 11 m/s. 73% of total. Now we have four approximate fan settings for drum air flow.

Note: The damper can be used in conjunction with fan speed controller.

What about using the stock damper for air control?

Here’s what I measured using an anemometer awhile back.

100% – 14 m/s (damper open)

92% – 13 m/s (damper 3/4 open)

71% – 10 m/s (damper 1/2 open)

42% – 6 m/s (damper 1/4 open)

24% –  3.4 m/s (damper cracked open; resting on closed)

11% – 1.5 m/s (damper fully closed)

Problem is there is no dial to set the damper. But it is possible to construct one using a 1/2″ split collar. One could use a 1/2″ washer attached to the split collar and make a dial and pointer arrangement.

The 1/2″ split collar also makes a nice damper stopper.

Happy roasting with your Huky 500!