Thermal mass flowmeters straight piping line requirements 

Generally, thermal mass flow meter can be installed vertically, horizontally or at any angle but requiring less straight pipe to make sure the flow from upstream is smoothly. User need to make sure the 10 pipe diameter lengths upstream and 5 pipe diameter lengths downstream.

Installation Requirements

Straight pipe line of thermal mass flowmeters installation required:

Standard standard pipeline thermal mass flow meter required
Curved pipe line in the upstream or downstream Curved pipe line in the upstream or downstream
Curved pipe line that may create turbulence in the upstream or downstream curved pipeline thermal mass flow meter straight pipeline required
There are valves or pressure controller or any other device may cause turbulence in upstream or downstream of the flowmeter thermal mass flowmeter straight pipeline required in valves pipe
If the pipeline of the flowmeter is upsized thermal mass flow meter staright pipeline required in upsized
If the pipeline of the flowmeter is downsized thermal mass flow meter staright pipeline required in downsized
On a horizontal pipe line, normal air or gas thermal mass flow meter straight pipe require in horizontal pipe thermal mass flow meter straight pipe require in horizontal pipe (2)

Above or under the pipeline           Side of the pipeline
On a horizontal pipe line, high humidity air or wet natural gas. thermal mass flow meter straight pipe required in horizontal pipe                   thermal mass flow meter straight pipe required in horizontal pipe

45 degree under the pipe line or just under the pipeline

thermal mass flow meter straight pipe require in horizontal pipe (2)                thermal mass flow meter straight pipe required in horizontal pipe

On the side of the pipe. Do not recommend to install the meter above the pipeline
On a vertical pipeline, when the density of the gas is higher than air make sure the flow goes from down to up