Propeller Meters -- Design
Propeller meters are bulk water meters, designed specifically to handle dirty
fluids. Originally these meters were designed for the irrigation market, where
the water can be silt laden, have plant material, small rocks, etc. There are
only three propeller blades and they have a very long body with the front edges
angled backwards. This allows vegetation to hit the rotor and slide off of it
without catching.
There is one basic design, which has been installed in a variety of bodies to
meet application requirements. They range from saddle types to in-line flanged
units with integral straightening vanes. If your situation is such that you cannot
easily shut down the water flow to remove the meter, specify a design that has
a removable flange top. This allows you to leave the body in the line and remove
the measuring element for cleaning.
Saddle meters
These are available in both strap on and weld on body designs. In both cases
we need to know the pipe I.D. and O.D. If the pipe is PVC or other plastic, tell
us and we will provide saddles with wider straps.
Flow ranges
The flow ranges of a propeller meter are different from the flow range in a typical
bulk water meter. Example - A 3" propeller meter is rated for 40 to 250
GPM, where a 3" standard bulk water meter is typically min/max/peak ranges
of 4/600/750 GPM.
Installation
Be sure to install these meters in a straight pipe with a minimum of 5 pipe diameters
upstream and 1 diameter downstream.
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