Dursty Media – In many application, it is observed that media carrying durst will affect the reading of the meter, As the designing of DP based FM like Orifice, Ventury etc is based on the parameters provided by the users, No calculation is taken into consideration for the durst carried by the media, but with no other option in gas flow measurement the DP based FM is being used although with In-accurate reading. The Thermal Mass FM will not such affected by the durst and gives output based on the velocity sensed, In case of accumulation of durst in sensor can be clean with in 15 mins. Also the designing of orifice plate which is made to create DP gives in accurate value if the durst get accumulated that particular hole hence not recommended for durst air.

Low Flow / Pressure Profile – The basic requirement of DP based Flow Measurement technology is to have differential pressure between inlet – outlet position to understand the flow but in the low flow & pressure profile, generation of differential pressure is poor hence In-accurate reading, whereas the thermal mass flowmeter can sense the flow velocity of 0.01m/S also.

Engine Efficiency – Many Boiler, Furnace, Gas based genset etc manufacturer needs high rangeability in flow measurement to understand the efficiency of their systems. The DP based Flow Meters are efficient when the flow is running in between 40 to 70% of Flow range, whereas the Thermal Mass flowmeter is having 100: 1 turn down ratio gives more accurate result.

Compressed Air – In many industries compressed air is being used to energize various machines, whereas accurate measurement is essential for energy management, quality control, chilling efficiency etc. Proper measurement is essential as generation of compressed air involves cost. Thermal Mass Flow meter can be used to check minimum flow with high accuracy, it can also be used to detect the leakage too in the pipe to avoid any wastage of air.

Bigger Line Size – It is very difficult to install DP based Flowmeter in bigger line size whereas Thermal Mass flowmeter can be installed in a 3/4 inch hole available in line. Also the DP based Flowmeters have multiple devices like Plate, DPT, Manyfold Valve, Tubing and Flow Computing Unit whereas the Thermal Meter is only one device whose sensor needs to be inserted.

Maintenance / Installation – As explained earlier in bigger line size the installation of DP based Flowmeter involves cost also for any installation of DP FM, need multiple devices interconnection, whereas in thermal Mass only one probe is getting inserted inside the pipe. Accordingly during Maintenance need proper shut down for DP FM whereas in Thermal FM only probe is required to clean in case of durst accumulation only.

Portability – In DP based FM, actually the Meter is designed based on the parameters provided by the User, which can not be used in different application, whereas the Thermal Mass FM is calibrated with Full Range than it can be used in multiple line size, different gases just by changing basic parameters in Set-Up menu and can be used in line size upto 5000mm or more.

OverAll Costing – For DP FM, since its more mechanical, the over all cost (Freight, Cutting/Drilling in Pipe, Installation & Maintenance) is higher and if it is for bigger line size than the cost will be more higher. Whereas in Thermal FM no such requirement hence overall cost is lesser than DP FM

Disadvantages of Thermal Mass Flowmeter –

• Need Frequent cleaning if the media is having heavy moisture.
• Can not be made to be used in steam.
• Can not be made to be used in liquid.