The flow sensor market: an introduction

Flow sensors are increasingly indispensable devices used across various industries by businesses and manufacturers seeking to accurately measure the flow rate of liquids, gases, or both. Sensors play a crucial role in modern technology, from ensuring efficient performance of HVAC systems to the ever-evolving computing technology of Industryamp;nbsp;4.0.

In this blog, we’ll be covering the broad capabilities of fluid and gas flow sensors within systems. That said, Flusso’s sole focus is on air and gas flow sensors that provide essential data for monitoring, controlling, and optimising processes across industries, from automotive and medical to a host of consumer appliances.

Flusso is proud to be emerging as a major player in the flow sensor space, offering miniature airflow and velocity sensors at scale with outstanding accuracy and reliability.

Different types of flow sensors and their applications

There are various types of flow sensor available on the market, and each is tailored to slightly different use cases. Below, you can find key information on how to differentiate between their functionalities and forms, as well as understand core applications in the space.

1. Differential pressure sensors

Differential pressure sensors operate by relating air or fluid velocity to pressure. These sensors typically consist of a constriction in the flow path that causes a pressure drop across the device. By measuring the pressure differential before and after the constriction, operators can accurately determine the flow rate of the gas or fluid passing through. They’re often used in HVAC systems — where they help regulate air and fluid flow for efficient climate control — plus chemical manufacturing facilities and pharmaceutical production. In each instance, they monitor air or liquid flow rates to regulate dosing and quality.

2. Vortex flow meter

A bluff body is placed in the flow of fluid, steam, or gas; vortex flow meters measure flow rate by detecting vortices shedded from the bluff, with the frequency of these vortices proportional to the velocity of the matter (and thus the flow rate). These highly accurate, durable meters are suited to chemical and petrochemical processing, water treatment plants, and energy management systems.

3. Rotameter

A vertical, tapered tube containing a float that rises or falls against a calibrated scale, thus providing a direct visual indication of flow rate. Rotameters are simple, reliable, and cost-effective, often used for measuring gas and liquid flow in lab experiments, chemical dosing systems, and industrial settings. Their simplicity and ability to operate without external power make them a preferred choice for many applications.

4. Optical flow meter

Optical flow meters use a non-contact measurement technique involving laser or LED light beams analysing scattered light patterns from particles within the fluid or gas. Precise and sensitive, such sensors are ideal for avoiding fluid contamination in the likes of pharmaceutical manufacturing, microfluidics, semiconductor fabrication, and biomedical research.

5. Turbine flow sensors

Turbine flow sensors utilise a rotating turbine placed in the path of the gas or fluid flow; the speed of the turbine is proportional to the flow rate. Though typically designed for liquid flow measurements, with appropriate design modifications and calibration, turbine flow sensors can also be adapted for gas flow measurements. They are employed in various industries, including petroleum, chemical, and pharmaceuticals.

6. Ultrasonic flow sensors

Ultrasonic flow sensors analyse the time it takes for ultrasonic pulses to travel upstream and downstream in a flow path (typically in fluids). There are two main types: transit-time and Doppler. Transit-time sensors measure the time difference between sound waves travelling with and against the flow, while Doppler sensors measure frequency shifts from particles within the fluid. Non-invasive and easy to maintain, they are often used in water and wastewater management, as well as in the oil and gas industry.

7. Positive displacement flow sensors

Positive displacement flow sensors are typically used with fluids. They work by periodically filling and emptying known volumes of a fluid into the system containing the sensor, measuring the displacement of the pre-existing contents, and translating that information into flow rate data. These types of flow sensors are suitable for applications requiring high accuracy, such as metering liquid flow in industrial processes.

8. Magnetic flow sensors

Magnetic flow sensors measure flow rate by detecting voltage generated by a conductive fluid passing through a magnetic field. They are commonly used in industries such as water treatment, pulp and paper, and chemical processing, where accurate flow measurement is critical. These types of flow sensors are typically larger than the increasingly compact technologies in the flow sensing space, including the standout offering from Flusso.

9. Coriolis flow meter

These measure mass flow rate by detecting how the Coriolis effect deflects fluids or gases as they pass through vibrating tubes. The deflection is directly proportional to the mass flow rate. Coriolis flow meters are renowned for their versatility and reliability, and can even measure fluid density; they’re most often used in chemical processing, food and beverage production, and pharmaceuticals.

Fresh focus on Flusso’s expertise

10. Flow sensors based on thermal principles

Last but by no means least: Flusso’s sensors hinge on the accuracy of thermal sensing principles. Our proprietary sensor technology contains a heating element and temperature sensors that detect shifts in the temperature profile as air/gas flows through the sensor.

In the absence of flow, the temperature sensors positioned around the heating element will display uniform readings. When there is flow, the variation in temperature between the upstream and the downstream sensors provides information about the flow characteristics.

Currently, our sensors operate in the anemometric mode: increased airflow leads to more heat dissipation from the heating element. This results in a change in the temperature difference between the upstream and downstream sensors.

Our thermal flow sensors are developed to measure air velocity and mass flow, and we’re proud to be at the forefront of innovation in the space. A little more detail on these two measurements below:

Air velocity

As the name suggests, air velocity sensors measure the speed of air passing through the system and the sensor. We’re spearheading a new era for air velocity sensor tech, bringing incomparably compact sensors that provide real-time data on the speed of airflow in various environments, ranging from HVAC systems to hyperscale data centres and beyond.

Our air velocity sensors offer a wide range of measurement capabilities, from low to high velocities, depending on the specific needs of the industry and use case. Air velocity sensors are compact and minimally intrusive, reducing the risk of interference with flow patterns and thus minimising the chance of inaccurate velocity readings.

In addition to HVAC and ventilation management in the likes of automotive and computing, environmental monitoring systems utilise air velocity flow sensors to assess air quality and minimise the impact of pollutants and contaminants. We’re finding that air velocity sensors have an integral role to play in research, refinement, and product development across various common and niche use cases; our sensors’ outstanding accuracy and repeatability bring partners real-time air speed and temperature measurements that are integrated seamlessly into existing flow paths.

Mass flow

Flusso’s mass flow sensors directly quantify the mass of air or gas passing through a system; they are more robust and less prone to performance drift over time compared to several of the other flow-sensing technologies covered on this page.

Flusso’s thermal mass flow sensors provide accurate and reliable flow measurements across several exciting and emerging applications. Here are some core industries we’re operating within and adding value to:

• Automotive: Used to regulate indoor air quality and pneumatic functionality such as smart seats.
• Hyperscale data centres: Detecting airflow rates to optimise server temperatures and optimise energy usage.
• Consumer appliances: From air purifiers to computing tech, mass flow sensors precisely measure airflow to regulate performance.
• Semiconductors: Facilitating the safe manufacturing and movement of semiconductor wafers to minimise contamination and bolster efficiency.
• Environmental monitoring: Measuring gas flow in emissions monitoring systems to aid regulatory compliance and pollution control efforts.
• Medical devices: Measuring and regulating precise drug administration in the likes of smart inhalers and large-volume autoinjectors.

Future-facing sensor solutions

It’s evident that flow sensors of various forms and functionalities are instrumental to helping industries increase their performance efficiency and optimise energy expenditure. From smart HVAC to the ever-evolving world of medical treatment, flow sensors facilitate precise measurement and control of fluids, gases, and air.

Core advancements in sensor technology have led to the development of Flusso’s extraordinarily accurate, robust, and seamlessly integrated air velocity and mass flow sensors based on thermal principles. Our product offering is proving invaluable to our partners as they develop new product features, become more sustainable, and otherwise push the boundaries of innovation.