Company Profile

Endress Hauser Flow Transmitters: Prowirl and Prosonic Signal Processing Platforms

Quick Answer: Endress Hauser Prowirl and Prosonic transmitters use different signal processing methods for vortex and ultrasonic flow measurement. Prowirl focuses on wet steam detection and mass flow for steam lines while Prosonic handles difficult acoustic paths in pipes with bubbles, solids, or low conductivity media. Silver Automation Instruments offers compatible replacement vortex and ultrasonic flow meters with similar signal processing at shorter lead times and lower landed cost.

This guide covers Prowirl 200 and Prosonic Flow 91/92/93 series plus newer Prosonic P and S models. We avoid marketing language and focus on what engineers actually see in the field.

Prowirl signal processing in steam and gas service

Prowirl vortex meters use a differential switched capacitor sensor. That sensor reads the bluff body vibration and ignores pipe noise. The transmitter converts that signal to volumetric flow at standard or actual conditions. Prowirl 200 can calculate mass flow for steam when you enter pressure and temperature. The onboard temperature compensation is useful for saturated steam lines where density changes quickly with pressure.

We have seen Prowirl F 200 units on steam headers in chemical plants across Southeast Asia. A common setup is a DN25 or DN40 meter on a 6 bar steam line at 165 °C. The transmitter sends 4-20 mA HART to a PLC and also stores a wet steam warning. In practice, wet steam alarm is a reason many plants choose Prowirl over older vortex meters.

One limitation is firmware. Some older Prowirl 72 and 73 units do not have the same signal processing. Replacement spares are not always available in Vietnam or Nigeria. Local distributors often quote long lead times for complete flow computers.

Prosonic signal processing for ultrasonic flow meters

Prosonic Flow transmitters rely on time of flight signal processing. The platform filters raw ultrasonic bursts and calculates transit time difference. That method works on clean liquids, hydrocarbon, demineralized water, and some gas flows. Prosonic Flow 93T is common in custody transfer systems where two paths are required. Prosonic P 100 is used in utilities for water and wastewater lines.

The signal processing inside Prosonic models handles aeration and solids up to a limit. In wastewater plants in the Middle East, a DN200 clamp on Prosonic P 500 can read flow even with 2 to 3 percent suspended solids. But when the pipe wall is rusty or scale builds up, signal quality drops. The same happens on old concrete pipes with uneven inner surfaces.

Most engineers skip this part, but clamp on ultrasonic meters need good pipe data. Pipe material, wall thickness, and liner type must match the on site condition. If a plant does not have as-built drawings, direct inline ultrasonic or vortex is easier to commission.

Alternatives from Silver Automation Instruments

Silver Instruments supplies vortex flow meters that cover DN15 to DN300 in 316L stainless steel. They handle steam, compressed air, and gas measurement. The digital signal processor filters low flow noise and provides stable output below 2 kg/h for small gas lines. A paint manufacturer in Indonesia replaced a Prowirl F 200 with a Silver vortex meter on a 10 bar compressed air line. The process team only needed to send pipe size, flow range, and signal type.

For ultrasonic applications, Silver Instruments offers inline and clamp on ultrasonic flow meters. Inline models suit clean water, RO permeate, and low conductivity liquids. Clamp on models suit retrofit jobs where you cannot cut the pipe. A desalination plant in Oman uses a Silver inline ultrasonic meter on seawater feed at DN150 and 52000 µS/cm. The unit sends 4-20 mA HART and Modbus RTU to the control room.