LL series roots flowmeter is a volume flow measuring instruments which is used to continuously measure volume flow of liquid. It is consisted of measuring part and totalizer part which can display cumulative flow on site. If it matches with photoelectric Pulse digital converter and flow totalizer, it can do remote distance measurement. The flowmeter uses tower wheel-type precision corrector. It is high accuracy and easy to regulate. It is widely used in raw oil and oil products to measure flow of high viscosity fluid.