Pulsar Non-Contacting Area-Velocity Flow Measurement Without a PMD

Reliable Open Channel Flow Measurement for Wastewater Treatment Applications

Accurate flow measurement is essential for wastewater treatment plants, industrial facilities, and environmental monitoring applications. However, some sites face significant challenges when a conventional Primary Measuring Device (PMD), such as a Parshall flume or V-notch weir, cannot be installed due to site hydraulics, civil engineering requirements, or installation costs.

HSA Asia Sdn. Bhd. supports industrial and environmental monitoring applications with advanced flow measurement solutions from Pulsar Measurement. In a wastewater treatment project in Asia, a non-contacting area-velocity flow measurement system provided a practical solution for measuring raw-water inlet flow without modifying the existing channel.

By combining the Pulsar MicroFlow, dBMACH3, and FlowCERT, the end user was able to measure flow rate, monitor system performance, and cross-check the inlet pump's flow rate without installing a new Primary Measuring Device.

The Challenge: Measuring Flow Without a Primary Measuring Device

Primary Measuring Devices, including weirs and flumes, are commonly used in open channel flow measurement. These structures create a predictable relationship between water level and flow rate, allowing a secondary instrument to calculate flow based on the measured level.

Although effective in many applications, installing a PMD can require substantial civil engineering work and additional project expenditure. Certain site conditions and existing channel hydraulics may also prevent a PMD from being installed.

At a wastewater treatment facility in Asia, the end user required reliable flow measurement at a location where the existing hydraulic conditions did not permit the installation of a conventional PMD.

The challenge was to obtain accurate open channel flow measurement without modifying the existing channel structure.

The Solution: Pulsar Non-Contacting Area-Velocity Flow Measurement

HSA Asia identified a non-contacting area-velocity flow measurement system designed for open channels where a Primary Measuring Device is not available or practical.

The solution combines three key components:

• Pulsar MicroFlow: Uses K-Band radar technology to measure surface velocity without contacting the flowing water.

• Pulsar dBMACH3: An ultrasonic transducer designed for open channel applications to measure liquid level.

• Pulsar FlowCERT: Processes the measurement inputs and calculates flow rate using the programmed channel dimensions and configuration.

By combining velocity and level measurements with the channel's programmed geometry, the system provides a practical approach to flow measurement without requiring a conventional PMD.

1. Pulsar MicroFlow – Non-Contacting Velocity Measurement

The Pulsar MicroFlow is designed to measure surface velocity in open channels using non-contacting K-Band radar technology.

The sensor transmits microwave signals towards the moving water surface. Reflected signals undergo a frequency shift, which the instrument analyses to determine surface velocity.

Because the measurement is performed without direct contact with the water, MicroFlow is suitable for applications where contact-based sensors may be difficult to install or maintain.

Key benefits include:

• Non-contacting surface velocity measurement.

• Radar-based measurement technology.

• Suitable for open channels and challenging site conditions.

• Can be used for velocity measurement or as part of a complete area-velocity system.

2. Pulsar dBMACH3 – High-Accuracy Open Channel Flow Transducer

The Pulsar dBMACH3 is an ultrasonic transducer developed specifically for open channel flow applications.

Its specialised sun and submergence shields support operation in demanding environments. Its zero effective blanking distance beyond the nose cone allows installation very close to the high-flow level, subject to the application and installation requirements.

In the area-velocity system, the dBMACH3 supplies level measurement data that is combined with the velocity readings from MicroFlow.

This combination enables the system to determine flow rate based on both the movement of the water and the channel's dimensions.

3. Pulsar FlowCERT – Flow Calculation and Data Logging

The Pulsar FlowCERT receives measurement data from the MicroFlow and dBMACH3 and calculates the flow rate using the programmed channel shape and dimensions.

The controller displays flow information on its onboard screen and includes data-logging functionality. According to the project configuration, measurement records can be stored on the supplied 32 GB Micro SD card for subsequent downloading and analysis.

These capabilities help operators review flow data, support operational monitoring, and assess the performance of existing equipment.

Successful Installation at a Wastewater Treatment Plant in Asia

The non-contacting area-velocity flow measurement system was well suited to the application because the end user did not want to modify the existing channel.

The installed solution enabled the facility to measure the raw-water inlet flow without constructing a new Primary Measuring Device.

The measured flow rate also allowed the end user to cross-check the inlet pump's flow rate, helping verify the performance of the existing equipment.

This project demonstrates how combining radar velocity measurement, ultrasonic level measurement, and flow calculation can address open channel monitoring challenges where conventional PMD installation is impractical.

Applications of Non-Contacting Area-Velocity Flow Measurement

Pulsar non-contacting area-velocity flow measurement technology can be considered for a range of applications, including:

• Wastewater treatment plants.

• Raw-water inlet and outlet channels.

• Industrial effluent monitoring.

• Open channel flow measurement.

• Environmental water monitoring.

• Existing channels where civil modifications are difficult.

• Applications where a Primary Measuring Device cannot be installed.

The suitability of the system depends on site hydraulics, channel geometry, water-surface conditions, and the required measurement performance.

Why Choose HSA Asia for Pulsar Flow Measurement Solutions?

HSA Asia Sdn. Bhd. provides instrumentation solutions for flow measurement, water quality monitoring, environmental monitoring, and industrial process applications.

Our team supports customers with product selection, technical consultation, system configuration, installation support, and after-sales service to help identify solutions that suit their project requirements.

For applications requiring open channel flow measurement without a conventional Primary Measuring Device, HSA Asia can assist in evaluating suitable Pulsar Measurement technologies, including MicroFlow, dBMACH3, and FlowCERT.