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
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
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
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