Can I measure flow in both directions through my flowmeter?
The flowmeter is designed and calibrated for flows in the direction of the arrow embossed on the flowmeter body. No damage will occur if the flow is reversed provided that the gas is clean. For higher flowrate the meter can be used in reverse flow with a correciton. See application “FLOW-Reverse Flow 4000 and 4100 Series Flowmeters” for a discussion on this correction. These flowmeters cannot determine the direction of the flow. If your setup presents the flowmeter with momentary flow reversals, such as during pump or valve operation, you may see significant measurement errors. Vane type pumps are especially prone to this problem. If you suspect flow reversals, look at the analog output on an oscilloscope to see if the instantaneous flow is going near zero. This type of momentary flow reversal will cause the flowmeter to read high. Contact the factory for more information.
