Natural gas filter differential pressure: how it indicates a blockage

The natural gas filter protects meters, regulators, and valves from contaminants. As it fills, the pressure drop across it increases.

Measurement before and after

Differential pressure is the difference between the upstream and downstream pressure of the filter.

Clean filter

At normal flow, the pressure drop should be relatively low and consistent with the manufacturer's specifications.

Clogged filter

As contamination increases, the differential pressure rises and flow may become restricted.

Correct monitoring

Differential pressure should be evaluated at a specific flow rate, as it naturally increases as the flow rate increases.