Panametrics DewPro MMR30, Installation & Operation Manual

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DewPro® MMR30 Installation & Operation Manual 7
Chapter 2. Installation Guidelines
2.3 Method II - Orifice at Inlet
Figure 6: DewPro with Orifice Restriction at Inlet
In case the application requires the dew point measurement under atmospheric pressure, the orifice flow restriction
is to be mounted at the inlet of the DewPro
®
bypass.This may not be typical for dryer applications. The dew point
reading will be lower since the water vapor pressure is reduced by the factor of the pressure drop across the inlet
orifice.
In this configuration, the outlet of the DewPro
®
bypass is not flow restricted and will be equipped with a 6 mm (1/4”)
tube fitting. In order to prevent back diffusion of water vapor from the ambient air, five feet of exhaust tubing should
be mounted to the tube fitting, or, better, a diffusion coil from Panametrics can be used.