×
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

Float Sizing for flow contol

Float Sizing for flow contol

Float Sizing for flow contol

(OP)
I need to design a float that is attached to an arm that will open or close a butterfly valve that controls the water level in a retention tank. It is identical the way the float works in a typical toilet. As the level decreases, the float moves down and opens the valve allowing more water in. As the water level rises, so does the float and that closes the valve. I've contacted the valve manufacturer and he said the shut-off torque for the valve is 850 in-lbs. I was figuring that the lever arm from the centerline of the valve shaft to the float would be about 36in. How do I calculate the size of the float so that will in fact float yet be able to provide the required torque to shut off the valve. If you can give me a hand with this I'd really appreciate it.

RE: Float Sizing for flow contol

torque = 850 lb-in
lever arm= 36 in
force required at float end = 850/36=23.6 lb
To have this force, flaot must have volume to displace this much of liquid.
Volume of float = 23.6/(density of water 0.036 lb/cubic inch) = 655 cubic inch.

The volume of your float = 655 + wt of its own/0.036

RE: Float Sizing for flow contol

Why dont you just buy it?

Dont try to overspecify a piece of equipment. Your concern would be to activate at a certain level - the vendor should provide the solution

Best Regards

Morten

RE: Float Sizing for flow contol

Directly controlled Float valves are slow and lethargic ones prone to problems.Try valves with pilot type float valves.The pilot could be as small as the one in the bath room and response will be far better and faster.You have one more advantage that the main valve need not be there near the tank controlled by the float- remote pilot.
For further details post your e-mail id  for contacting.

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