×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Actuator:Sluice gate

Actuator:Sluice gate

Actuator:Sluice gate

(OP)
Hi there,

We are specifying 84" x 144" sluice gates in one of our projects and we expect very high torque and thrust required for the actuator to pull up the gate under a head of 40ft water. What type/brand of electric actuators do you suggest?

Thanks

RE: Actuator:Sluice gate

PersianEng,

Have you considered a hydraulic piston actuator?  Or does the spec require electric?

RE: Actuator:Sluice gate

It may help is you gave the torque needed for the actuator, and also opening/closing speed.

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

RE: Actuator:Sluice gate

Ashereng is right.  Speed can be an important spec.  Electrics usually operate at only 12-15" per minute.  If this stroke is 144", it might take 10 minutes to open.  Likewise, if there is a power failure it may be necessary to maintain control of the valve.  A hydraulic accumulator can handle multiple strokes after power is lost.  This accumulator would push fluid into the hydraulic actuator.

However, hydraulic actuators can be tall.  If there is a height issue, electrics may be the way to go.

RE: Actuator:Sluice gate

(OP)
Valid point. However we do not know the actual operating speed and only know that it does not have to be fast; since the gate is operating rarely upon plant shut down or startup.

Hydraulic actuators are not allowed in most water treatment application because of the possibility of contamination and housekeeping considerations. Therefore we are bound to use electric actuators.

RE: Actuator:Sluice gate

If there is no need for speed, then almost any actuator can be geared to do the work.

What actuator are you using now?

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

RE: Actuator:Sluice gate

If hydraulic fluid is not acceptable, you could also use air.

RE: Actuator:Sluice gate

(OP)
Ashereng,

I see what you are saying; that's true.Thanks.

aticooper,
Air is clean but the air cylinder to handle huge thrust load has to be very big.

RE: Actuator:Sluice gate

PersianEng

What is the thrust required?

RE: Actuator:Sluice gate

The height of the cylinder actuator (either pneumatic or hydraulic)  will be within inches of the height of the electric actuator.
With the valve open, the lead screw will have to pass through the electric actuator and stick up into the air. (probably inside a fixed protection tube)
So you can have a 144" stroke cylinder, or a 144" long ACME- threaded actuating screw.  

A pneumatic cylinder will presumably run on your plant air system, so typically that means you can have 80 psi you can count on.  

A hydraulic actuator typically draws from a 1500 psi system,
So the relative areas of the pneumatic vs hydraulic are almost 20:1 (or a 4.3:1 diameter ratio, neglecting the (important) cross-sectional area of the actuating rod)

If you need fail action, you can use a pneumatic accumulator about the size of a tank car, or a hydraulic accumulator which would be much smaller, or you could use an electrical failsafe which would be basically batteries and an inverter, and comparatively quite compact.  



RE: Actuator:Sluice gate

PersianEng
I agree that hydraulics are a housekeeping problem but that relates to "hydraulic systems". One option you may want to consider is a hybrid unit where the controls and power to the unit is electrical and the actuator is a sealed self-contained hydraulic unit. Check out www.rexa.com
Regards,
ABScott

RE: Actuator:Sluice gate

abscott,

We're fitting a Rexa unit to one of our gas turbines as a trial replacement for the pneumatic IGV actuator. Do you have any experience of the Rexa products? I'm looking for any operation pitfalls or weaknesses which Rexa clearly won't be publicising.

----------------------------------
  I don't suffer from insanity. I enjoy it...

RE: Actuator:Sluice gate

ScottyUK

We mount them on large globe valves for power plants and pipelines where large pneumatic actuators do not provide the precise control necessary. They are expensive -- but provide very accurate control. We haven't had any problems as far as I know.
Regards,
ABScott

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources