Cuprum & PWMaster
PWMaster
Hey Cuprum, I’ve been building a self‑regulating fan array for a bookshelf, and I’m trying to nail down the exact static pressure and airflow curve. Do you have any tricks for perfecting a cooling loop around a non‑standard shape?
Cuprum
Sure, first make sure every joint is tight—any leak throws off the pressure reading. Measure the static pressure with a manometer at the fan inlet and outlet, then plot that against the flow rate you get with a low‑flow meter. For a weird shape, lay out the loop on a piece of cardboard, run a thin tube through it and watch where the air slows; that’s where you’ll need a larger pipe or a less restrictive bend. Keep the path as straight as possible, use 90‑degree elbows only when you can’t avoid a sharp angle, and always leave a small gap for air to fill in. Test with a real fan at full speed, record the numbers, tweak the pipe diameter or the fan speed, and repeat until the curve fits the design. Patience and precise measurements are the only ways to get a true, repeatable loop.
PWMaster
Nice checklist, and I’ll add a couple of my usual tweaks. Measure static pressure with a differential gauge at each elbow and pull the loss coefficient k from the latest data sheet—those 90° elbows are usually k≈4.3 for 2″ pipe, so if you’re using 3″ you’ll need to cut that to around 2.5″ to stay on budget. Don’t forget a clean filter on the inlet; a dirty filter will shift the curve overnight. Keep a log of every test, because one bad reading can skew the whole loop. Good luck, and let me know if the fan’s pitch changes after you tweak the pipe diameter.
Cuprum
Sounds solid, but remember to double‑check every connection—any slip and the static pressure will drop. Keep the logs tidy, label each test clearly, and don’t skip the filter check twice a week; a clogged filter can throw the whole curve off. Once you’ve hit the target pressure, lock the pipe size in place with clamps so the diameter doesn’t shift during operation. Let me know when you run the final run‑through.
PWMaster
Got it, will tighten every joint, clamp the 2″ pipe, and run a final pressure sweep at 55 L/s. I’ll log the differential readings at each elbow, filter pressure drop, and compare them to the 4.3 loss coefficient from the 90° data sheet. Expect the curve to plateau within ±1 % of target. Will ping when the run‑through is complete.
Cuprum
Sounds like a thorough plan. Keep the logs clean, double‑check the clamps, and when you hit that 55 L/s run, make sure the readings stay within that one‑percent band. Let me know how it turns out.