Digital Liquid Mass Flow Meters / Controllers LF-F/LV-F series
Overview
The LF-F/LV-F Series are digital liquid mass flow controller using a Peltier element which cools the liquid rather than the more common thermal heating element. This gives the advantage of removing the risk of boiling those chemicals that have a low boiling point, thus allowing a greater range of chemical control.
Features
- Offer micro-litre to ultra low flow rate control.
- Enable precision flow control of low boiling point and high viscosity liquids.
- Ultra clean.
Manufactured by HORIBA STEC
Specifications
Measurement Techniques
Cooling measurement method
The flow rate sensor in the LF-F/LV-F series of fine mass flow controllers for liquids consists of an electronic cooling element (Peltier element) that is in contact with a capillary tube, as well as several temperature detection elements. When the liquid is flowing, the sensor detects the temperature rise (ΔT) corresponding to the flow rate and displays it as flow rate. Unlike methods where heat is added, this cooling method enables flow rate measurement of liquids with low boiling points. It also prevents problems with interference due to the influence of secondary discharge (vaporization) and makes accurate flow rate measurements possible.
Structure/Operating principle
The LV-F series of mass flow controllers and LF-F series of mass flow meters use the same measurement principle. The LV-F also has a piezo actuator valve and an internal comparison control circuit. These compare the flow rate setting signal and the flow rate output signal and automatically control the valve aperture so that the two signals will match to control the liquid. Since they use a feedback control system, there are no flow rate variations as a result of external factors, and, there fore, stable, accurate control is possible. The use of piezo actuator valve, which is both stable and does not generate heat, as the control valve makes these units ideal for flow control of liquids with low boiling points.