Versatile Liquid Flow Meter for up to 120 ml/min and Highly Viscous FluidsSensirion Liquid Flow Meters SLQ QT500

The SLQ-QT500 features a flow range of up to 120 ml/min for water-based and hydrocarbon-based liquids, such as alcohols, solvents, oil, fuel and adhesives. It is the first choice for measurement of liquids containing particles or with a high viscosity. The SLQ-QT500 in combination with one of the SCC1 sensor cables can be easily integrated into demanding coating systems in the semicon industry, as well as into a wide array of dispensing and liquid flow systems in other industries.

The high sensitivity and measuring speed offers new possibilities for the monitoring and control of fast dispensing processes. The sensor is available with calibrations for H2O and isopropanol (IPA). Due to its micro-thermal measurement principle and large inner diameter, the measurement performance of the SLQ-QT500 does not depend on the viscosity itself, and so there is no strict upper or lower viscosity limit (e.g. kinematic viscosities of up to ~1000 mm2/s). It is also ideal for liquids that contain small particles, as long as they do not abrade the quartz glass tube.

For wetted parts, only PFA for the fittings and quartz glass for the inner flow channel have been chosen. As with all other Sensirion liquid flow meters, this reliable device has no moving parts and measures through the wall of a straight flow path.

The SLQ-QT500 liquid flow meter in combination with one of the SCC1 sensor cables offers a modular solution with a suitable electrical interface for almost any environment:

  • The SCC1-USB sensor cable provides a plug-and-play connection to a PC for operation with Sensirion’s viewer software or user-built programs for laboratory and desktop applications.
  • The SCC1-RS485 sensor cable featuring a stable RS485 interface and including advanced functionality such as dispense volume totalizer, automatic dispense detection, and data buffer for asynchronous read-out is designed for demanding industrial automation environments.
  • The SCC1-Analog sensor cable allows simple and quick readings or integration into generic controller systems without programming. In addition to a 0-10 V analog voltage output, the cable provides a configurable digital (high/low) output that can be programmed to act as a flow switch or pulse output.


  • Maximum flow rate for hydrocarbons and water-based liquids: 120 ml/min
  • For high- and low-viscosity liquids or for liquids with small particles
  • Fast response time down to 50 ms
  • Highest sensitivity down to the lowest flow rates
  • RS485, USB, or 0-10 V analog voltage output
  • Straight flow path, no moving parts
  • Assured purity
  • Superb chemical resistance
  • Inert wetted materials: PFA and quartz glass
  • Maximum recommended operating pressure: 12 bar


  • High-end semiconductor process control
  • High-viscosity applications
  • Industrial automation
  • Fast dosing operations