Characterizing a filter with a pressure controller & mass flow meter
A common application of Alicat’s mass flow and pressure devices is the characterization of a static device with pressure drop, most commonly a filter or fixed orifice. Filters and static orifices have pre-defined curves for the relation between pressure and flow rate. A customer will most likely want to develop this curve or test a specific filter to ensure that it agrees with the published data.
Depending on the specific device under test, the pressure or flow rate will need to be controlled while the other is measured. The most common scenario for filter characterization is to control the mass flow rate and measure the differential pressure which is what this lab replicates. However, you can also control the differential pressure across the device under test and measure the flow rate.
Using differential pressure control to characterize a filter
An Alicat differential pressure controller is used to characterize a filter’s flow vs. a pressure drop curve. A PC-15PSID-D pressure controller is used to set the pressure drop across the filter, while an M-10SLPM-D mass flow meter is used to measure the flow rate required to generate that pressure drop.
As an alternate configuration, the flow meter may be placed upstream of the pressure controller. Mass in equals mass out.
Advantages: Serial input of the desired pressure drop allows the user to run canned scripts at known time intervals while a common control interface is used for both pressure and flow.