Extreme duty check-valve?

[TGTimm]

We used a pumped HL system. I'd like to automate the pump, but this would require a check valve that could survive our extremely high carbonate hardness. So far, nothing has lasted more than a month. We've tried swing-type valves, ball-cone valves, and disc-type valves. All accumulate so much calcite in so little time that the pump would just run continuously. Additionally, our HL likes to eat metal where it encounters restricted flow (CO2 release?).

Any ideas?

[CPESystems]

Solenoid valve

Have you tried using an electric solenoid valve? Connected it to one leg of the power to your pump, it opens when the pump starts and closes when the pump shuts off.

[TGTimm]

Thanks, Don. I've been thinking along those lines--use a pressure tank and pressure sensor to detect the demand for HL, turn on the valve and the pump. I'm thinking a solenoid-actuated ball valve might survive the longest in our "hungry" and calcium-laden water, but a poppet-style pneumaticalyy operated valve might work, too--if it's rebuildable.

[Starcat]

Industrial Duty

A pneumatic or electrically operated Globe Valve [2-way] such as used in steam condensate return service may be considered. They are rugged.
They are made by a number of outfits such as Johnson Controls. The Spirax ones look good these days. I have one of those picked out for a boiler job.
They are also available in Stainless.
This type would likely be less problematic than a solenoid for extreme duty and offering very positive shutoff.

[TGTimm]

Excellent advise, Warren. I'll look into those valves. Probably not cheap, but considering that our HL pump--3hp 3phase--runs almost continuously all day long, the savings in electricity should offset the costs of putting this together pretty quickly.

Any advise on an appropriate pressure tank? Our HL is at 195F, ~60 psi. I'd like to use a bladder-type tank as I think our HL cooling in the tank would suck any airspace out rather rapidly--and also to help keep corrosion down. Since the only purpose of the tank is to sense demand, I don't think it needs to be very large--in fact, smaller should be better so we don't waste too much water getting to the hot stuff. I'm sure insulating the tank would also help with this.

Same question RE the pressure switch--I don't think a water well switch would last very long.

[Natrat]

There are lots of environmentally sealed pressure switches available. Look for something that isolates the switch from harsh chemical...a flexible plastic diaphragm with a packed silicon switch should work, no?