Folks,
The valves arrived today, and appear to be in good order. Basically a stainless steel valve body with a 1/2" bore.
These are available in a variety of wiring modes, but the most likely for us is a power-on=open, power-off=closed mode. It operates on VDC 5-24. Apparently they will also work on VAC 5-24.
Use cases tested:
Normal Operation:
Apply 00VDC : Valve closed (OK)
Apply 05VDC : Valve open (OK - current draw of 150mA declines to 0 as valve closes)
Apply 12VDC : Valve open (OK)
Apply 24VDC : Valve open (OK)
Apply 00VDC : Valve closes (no current draw - motor is powered via a capacitor in this configuration)
Fail modes:
Apply 12V, jam valve open: Valve stalls. No oscillation, no back off. No current change noticable as a detection mechanism. Valve closes completely after removing blockage, but only just (capacitor charge will disipate with time, meaning that after a while the valve will remain partially open if left in this state for some time).
Disassembly test:
The unit has a ribber seal to minimise risk of liquid penetration. I broke it down only to the point of identifying the gears - I wasn't up for remembering the gear configuration at this point to verify the opperating modes for the motor
. Suffice to say it looks very well built for the price, with no plastic moving parts, and silicon grease on all friction surfaces.
Verdict:
All up - these look like the ducks nuts! I'm going to do a hydrostatic test overnight (with any luck) to make sure the valve itselve is a good seal, but for our purposes this is going to do the trick nicely.
I've attached a couple of pics of the outside of the unit (didn't think to do the inside while I had it open - sorry).
Pros:
Super fast delivery - UPS (left China Friday, arrived Monday afternoon)
Very reasonable price
Cons:
Payment requires an international bank transfer (CBA charged me $30 for the honour, and then a fee for paying by VISA on the day).
Star rating - Mega!
I'm going to ask around our club to see if anyone is interested in a bulk buy, but I'd be cautious about bringing in too many. 24 units will keep us under the import duty threshold, but many more will draw attention.
Andy