Pelton Turbine Needle Valve

[mls1]

We have a small Pelton Wheel type hydroelectric project with two needle valves. The needle valves have an internal hydraulic actuator and one of them has a compromised seal and is leaking oil. That is a big problem in the environmentally sensitive area. I've seen needle valves with a hydraulic spear actuators that were external so that a leaking seal would not get into the water. We are thinking this would be a good option for fixing the problem. I have not found many manufacturers of needle valves, are there any in the US? Any additional recommendation to fix this issue? Thanks!

 

[btrueblood]

What size?

 

[btrueblood]

Also, does it have to be hydraulic acutated, or could it be manual, or electric? Any idea what the flow range and head pressure range can be?

 

[btrueblood]

Yeesh, I should wait a bit before hitting the submit button. How hard would it be to rework the valve to expose the stem (add in a packing sleeve) and then use an off-the-shelf actuator of whatever type?

 

[mls1]

I don't have the physical size handy but attached is a photo of the turbine and you can see the two valves. I don't know about the feasibility of modifying these valves but I think replacement may be warranted simply because they took a pretty good beating a few years ago when the penstock was replaced. The contractor did not use proper controls and rock were spit through the valves. We're lucky the pelton wasn't damaged.

The turbine is a Sanden from Norway from 1985. It's rated 850kW with 550Ft of head and 360RPM. I don't have the actual head available but it's at least several hundred feet.

I tried to attach two photos, one of the inside and one of the outside, but it may reduce to just one. I'll post the other one if need be.

 

[mls1]

Here's the other photo.

 

[btrueblood]

Ok, when you said small I was thinking a few to 10 hp, that looks like a bit more. And the generator looks like it ties to the grid, so control for synchronous speed is important? It might be best to get the bespoke valve, and not try to jury rig one from another manufacturer.

Have you contacted the manufacturer to see if they have options available?

If you must use hydraulics, consider finding biodegradable fluids, or propylene glycol/water mixtures, to reduce environmental impacts.

 

[btrueblood]

Finally, if you're really stuck, call these guys and see if they can help:

http://www.canyonhydro.com/contact.html

 

[LittleInch]

what you have there is not commonly called a needle valve - most of those have literally needles like you would darn a sock.

What you have is an axial control valve or sometimes axial plug control valve.

Mokveld in Netherlands make very good ones, also petrolvalves, Dyna-flow and others, but use these search terms and you'll be better informed.

Most of these operate via a gear mechanism to an external actuator, but then have some interference with flow.

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