Float Switch Buoyancy Comparison

Float Switch Buoyancy Calculations

Note: When calculating buoyancy for liquids other than water, make adjustments in step 3.

5.5’’ Float (Non Weighted)

1. Weight of the 5.5’’ Float in air = 1.12 pounds

2. Volume of the displaced liquid = 87.12 cubic inches

            4.189r3 Where r is float radius in inches
            (4.189) (2.75)3 = 87.12 cubic inches

3. The weight of the displaced volume of liquid = 3.138 pounds

            Water = 62.248 pounds/cubic foot
            62.248/123 = pounds/cubic inch = 0.03602 pounds/cubic inch
            (0.03602 pounds/cubic inch) (87.12 cubic inches) = 3.138 pounds

4. (Weight of the displaced volume of liquid) – (weight of the float) = total net buoyancy

            (3.138 pounds) – (1.12 pounds) = 2.018 pounds, total net buoyancy

 

4.5’’ Float (Non Weighted)

1. Weight of the 4.5’’ Pipe Mount Float in air = 0.35 pounds

2. Volume of the displaced liquid = 57.73 cubic inches

3. The weight of the displaced volume of liquid = 2.08 pounds

            Water = 62.248 pounds/cubic foot
            62.248/123 = pounds/cubic inch = 0.03602 pounds/cubic inch
            (0.03602 pounds/cubic inch) (57.73 cubic inches) = 2.08 pounds

4. (Weight of the displaced volume of liquid) – (weight of the float) = total net buoyancy

            (2.08 pounds) – (0.35 pounds) = 1.73 pounds, total net buoyancy

 

The above calculations compare the 5.5’’ Stainless Steel Float Switch to the 4.5’’ Float Switch.
The larger 5.5’’ float displaces over 40% more liquid and has over 15% more net buoyancy. 

 

Affiliations

  • American Water Works Association
  • Chesapeake Water Enviroment Assocaition
  • Environmental Protection Agency
  • National Rural Water Association
  • Water Enviroment Federation
  • Water Quality Association
  • Whel-Tech