The best meter for odorant injection systems

You need a meter, but NOT a gear meter
accurate metering pump

No matter which pump you use to inject chemicals, you still need a method to verify that the chemicals were actually injected. You can have the most sophisticated dosing pump in the world, but if the tank is empty, the stroke count doesn’t mean a thing. 

The choice of meter technology is the next most important consideration. The low viscosity of odorants, require that they be measured by a meter with tight internal fit. A piston style meter, with its 0.0002” tolerances is far superior to gear style meters with at least 5 times more internal clearance. When the fluid viscosity is less than 5 cps, the large gap on the side of the gears allows fluid to slip by unmeasured. Be careful when reviewing accuracy claims for gear meters, they are usually based on a much more viscous fluid and not applicable to mercaptans.

Lastly, the application is subject to abrupt on/off flow, the potential for slight reverse flows, vibrations and turbulence. Through the use of sophisticated, anti-dither software, Max can give you an accurate flow rate and total and only report the net forward flow; something that simple proximity style encoders often overlook. 

Max equipment specified:

The Model P213 is used to accurately measure instantaneous injection rates from 1 - 1500 cc/minute. For instantaneous rates above 1500 cc/minute the Model P214 is the recommended meter. If you would like a quote for a similar project, please let us know.


We installed a Max Model P213 meter 25 years ago and placed a spare on the shelf. That spare is still sitting there with the shipping caps in the ports - Mike P. Williams Pipeline Co.

Products Specified for this Application

Precision low flow meter Model P213
0.5 to 1800 cc/min (0 to 0.48 gpm) with a 210 bar (3000 psi) pressure rating
High accuracy flow meter Model P214
5 to 10,000 cc/min (0 to 2.64 gpm) in 210 bar (3000 psi) and 500 bar (7250 psi) versions