Thermal mass flow controller LV-F series

for liquidsdigitalprecision

The LF-F and LV-F Series are digital liquid mass flow controllers using a Peltier element which cools the liquid rather than using the more common method of thermal heating. This technique removes the risk of boiling chemicals with a low boiling point, thus allowing for greater 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. Measurement Techniques Cooling Measurement Method The flow rate sensors in these mass flow controllers for liquids, consists of an electronic cooling element (Peltier element) which 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 Both The LV-F 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, therefore, stable and accurate control is possible.