We offer the widest product range of low-flow (mass) flow meters and controllers on the market. Numerous styles of both standard and bespoke instruments can be offered for applications in laboratory, machinery, industry and hazardous areas.
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Learn more about how Coriolis-based flow meters can be used as microfluidic flow meter instead of thermal flow meters. Read the customer story of a microfluidics system builder who used Bronkhorst products.
Are you looking for technical documentation, are you interested to learn more about the measuring principles of Bronkhorst products, or you do want to get in contact with a Bronkhorst Service Engineer? This section will guide you to the relevant service & support topics.
Bronkhorst High-Tech BV the leaders in Mass Flow Meter / Mass Flow Controller technology for gases and liquids, Pressure Controllers and Evaporation Systems.
As is the case with gases, the inline principle is used to measure the mass flow rate of liquids. This ‘inline measurement’, also known as ‘direct through-flow measurement’, can be distinguished in two measurement principles: Constant Temperature Anemometry (CPA) and Constant Power Anemometry (CPA). As the measurement occurs by ‘sensing’ the flow in the main flow channel of the liquid flow rate measurement device, these principles have no bypass sensor.
A thermal mass flow sensor uses the thermal properties of liquids to measure their mass flow rate. To this end, as can be seen in Figure 1, heat is introduced into the streaming liquid by a heater, and the (temperature) sensor measures how much heat is absorbed by the liquid. In these thermal mass flow meters for liquids, the heater as well as the sensor are built around a stainless-steel main flow channel tube with no moving parts or obstructions inside the tube.
The heater/sensor assembly is arranged around the tube and, by following the CTA principle, a constant difference in temperature (ΔT) is created. In the current setup, the first element operates as a temperature sensor, and the second element (downstream) works as a heater, as shown in Figure 2. The heater is heated to a certain constant temperature difference (ΔT) over the medium temperature. The actual mass flow rate is calculated by measuring the variable power required to maintain this constant temperature difference as the liquid flows passes the sensor.
The principle of CPA is similar in some ways to CTA. In this case, however, the two elements are used both as heater and as temperature sensor, as shown in Figure 3. Both elements are provided with an equal amount of constant power. The temperature difference (ΔT) between them is a measure for the liquid mass flow rate.
Liquid flow control can be achieved by integrating a control valve onto the body of the liquid mass flow meter or by adding a separate close-coupled control valve. Bronkhorst liquid flow control valves have a purge connection to eliminate air or gas during start-up. The electronic control function is part of the normal circuitry of Bronkhorst thermal liquid mass flow meters.
Please have a look at our blog series ‘How to handle low liquid flows?’ with recommendations for a setup for low liquid flow rates of typically less than 100 grams per hour.
Bronkhorst High-Tech designs and manufactures innovative instruments and subsystems for low-flow measurement and control for use in laboratories, machinery and industry. Driven by a strong sense of sustainability and with many years of experience, we offer an extensive range of (mass) flow meters and controllers for gases and liquids, based on thermal, Coriolis and ultrasonic measuring principles. Our global sales and service network provides local support in more than 40 countries. Discover Bronkhorst®!