ARMAC DevNotes · pages: Overview · Design & Calculations · Throttle Pressure-Drop Tables · Build & Commissioning · Calibration
Tie-in (two fittings, no fabrication)
- 50 mm T at the pump discharge -> high-side tap (HIGH, ~5.1 bar)
- Existing plugged 50 mm outlet, downstream of the manual tap -> low-side return (LOW, ~1.5 bar). Confirm it is downstream of the tap and not on the high-pressure bypass -- it flows the right way on first open if so.
Branch components (high -> low)
| # | Component | Note |
|---|---|---|
| 1 | Needle valve | flow trim + sheds surplus pressure; rated >= 6 bar |
| 2 | Solenoid valve (12 V) | on/off; rated >= 6 bar |
| 3 | Dosatron Huiji DN009 | 10% unit; vertical, ports at top, suction at base |
| 4 | Check valve | already purchased; oriented high->low, blocks low-side back-feed |
| 5 | 3-way suction valve | gel <-> clean water |
| 6 | Concentrate drum | + foot valve + strainer; short suction, lift < 1 m |
| 7 | Clean-water flush source | for the mandatory shutdown flush |
Branch pipe: 25 mm, reducing to G3/4" at the injector; high-side leg rated for the ~5.1 bar high side.
Fail-safe wiring (de-energised = safe)
- Solenoid normally CLOSED -- branch isolated on power loss.
- 3-way de-energised port = clean water -- suction never sits on gel when off.
- Check valve blocks the low side back-feeding the idle branch.
Consumables
Neat concentrate draw ~= 1.7-2.0 L/min:
| Application | Barricade used |
|---|---|
| 15 min | ~27-30 L |
| 30 min | ~54-60 L |
| 60 min | ~108-120 L |
Commissioning & calibration
- Confirm return side. At 120 L/min, open the branch briefly; confirm flow runs high->low (pump-side T -> plugged outlet). If it back-flows, the outlet is on the wrong side of the tap.
- Measure the two flows (wide open, then throttled) and check the expected DeltaP against Throttle Pressure-Drop Tables -- this replaces the original guesstimate.
- Set the needle valve. 3-way on clean water, open the solenoid; trim the needle until the branch draws ~2000 L/H (~= 33 L/min) -- bucket-time a temporary return or read the rise on the main flow sensor.
- Calibrate the dial (key test). Suction into a graduated container of neat Barricade; run for time t; record concentrate drawn DeltaV_gel and combined delivery Q_total (main flow sensor). Trim the dial until C = DeltaV_gel / (Q_total x t) = 0.014.
- Viscosity check. Confirm the piston primes and meters neat Barricade without stalling; if not, pre-dilute to a pumpable stock and re-target the dial.
- Flush verification. 3-way to clean water, run >= 2 min, confirm the branch clears. Mandatory every shutdown -- set gel kills these units.
- Inlet spot-check. A gauge on the Dosatron inlet should read ~2 bar in dosing; approaching 6 bar means the needle valve is too far open.
Control logic (for AR3 / TestSys)
Two actuators only -- solenoid and 3-way; no booster relay. State machine:
- Arm: 3-way -> gel, open solenoid (branch driven by the tap DeltaP). Interlock: only arm when the main flow sensor confirms delivery (dry-guard + correct operational condition).
- Disarm: 3-way -> clean water, hold solenoid open >= 2 min to flush, then close.
- Fail-safe: any fault -> solenoid closed, 3-way to clean water.
To be ported into the existing AR3 Arduino code (JF format) and validated on TestSys.