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davef
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Joined: 14/05/2006
Location: New Zealand
Posts: 499

Posted: 09:32pm 07 May 2014

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I am looking for an electrically controlled ball valve for 50mm pipe for my microhydro project. Preferably 24Volt, but heh ...

I haven't had much luck sourcing something in NZ, so hoping for some keywords that would point me in the right direction.

Thank you,
davef

PS latching or low current as well.Edited by davef 2014-05-09

VK4AYQ
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Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 12:13am 08 May 2014

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Hi Dave

I have used a windscreen motor with a threaded rod in the output as a push pull device that could be attached to the ball valve handle, a couple if relays and limit switches for polarity reversal and limit stops, can be made very cheap as a controller but some electronics would be needed to control it.

The other possibility is a 2 inch control valve used in irrigation systems, they use a diaphragm and can be controlled by DC 12 volt I think but where quite expensive from memory.

All the best

Bob

Foolin Around

davef
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Joined: 14/05/2006
Location: New Zealand
Posts: 499

Posted: 01:15am 08 May 2014

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Bob,

Thanks for the windscreen motor suggestion.

My son come up with a similar concept, changing rotary motion into a linear motion such that 180 degrees rotation would open the valve and continuing through the other 180 degrees would close it. He just didn't suggest how to make it!

2" valves with solenoids are up in the $200-$300 ballpark, ouch!

Cheers,
Dave

Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 03:07am 08 May 2014

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You have not quoted what degree of control you want or at what operating pressure.

Another method would be to use a bank of solenoid valves, like the cheapish 1 inch garden irrigation solenoids and just switch on how many valves you need to control flow.

For example 4 x 1" solenoids will give the same flow as 1 x 2" solenoide valve, but you do need enough head pressure to open them (normally 30 psi +++)

Also some irrigation solenoids come with manual flow control adjustments, so you could adjust the flow rate through each valve to suit requirements or for a number of valves used.

Pete.

Sometimes it just works

davef
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Joined: 14/05/2006
Location: New Zealand
Posts: 499

Posted: 09:50am 08 May 2014

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Pete,

About 20 metres of head (28 psi)and I just want ON/OFF control. Also, I want to keep the "loss of head" at a minimum.

Thanks for the suggestion.

Dave

yahoo2

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Joined: 05/04/2011
Location: Australia
Posts: 1166

Posted: 01:28pm 08 May 2014

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A crusty old linear actuator would do the job. say a 100mm stroke with non adjustable limit switches in the gearbox. they are slow but have plenty of torque.

photo misappropriated from online auction site

I'm confused, no wait... maybe I'm not...

davef
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Joined: 14/05/2006
Location: New Zealand
Posts: 499

Posted: 05:45pm 08 May 2014

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yahoo2,

Thanks for that. My original idea was to use a linear actuator ... until I saw the prices.

Also, I hadn't even considered whether or not a linear actuator could "back-drive" or even hold something in position with the power off :(

The wiper motor is looking better all the time. I have an old Morris Oxford in the backyard that is going to offer it's wiper motor for a trial.

Thanks everyone for the suggestions, now to make something!

Cheers,
Dave

yahoo2

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Joined: 05/04/2011
Location: Australia
Posts: 1166

Posted: 06:35pm 08 May 2014

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I get mine from c band satellite dishes. second hand they are worth virtually nothing BUT most of them are 24 inch stroke. they are rated at 36 volt but should still work fine at 24 volt.

A standard duty 12 inch actuator shouldn't be any more than $70 new.

what about a power window mechanism? has that got built in limit switches?

I'm confused, no wait... maybe I'm not...

davef
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Joined: 14/05/2006
Location: New Zealand
Posts: 499

Posted: 07:20pm 08 May 2014

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Power window, now that sounds interesting ... I'll check that out. I also have a Toyota in the frontyard, going for junk, with power windows in it. Maybe, it is my lucky day!

Thanks yahoo2

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