AUTO SMAPLER HAVING AN ACCURATE ISOKINETIC SAMPLING CONTROL FUNCTION THROUGH AUTOMATED DIFFERENTIAL PRESSURE COMPENSATION AND METHOD FOR CONTROLLING ISOKINETIC SAMPLING USING THE SAME

摘要

An auto-sampler having an accurate isokinetic sampling control function through automated differential pressure compensation and a method for controlling isokinetic sampling using the auto sampler are provided to auto-control a flow control valve such that an absorption flux indication value corresponds to a calculated isokinetic sampling flow rate and correct an error generated when a difference between the total pressure and static pressure of exhaust gas to precisely measure the flux of the exhaust gas to thereby achieve exact isokinetic sampling. An auto-sampler is connected to a probe including a pitot(2), a suction nozzle and a temperature sensor(3) through an umbilical cable(50). The auto-sampler includes a temperature signal line(110) delivering a sensed chimney temperature signal, a sample transfer tube(120) in which an inhaled exhaust gas sample is transferred, a vacuum pump(125) providing an absorption force for transferring the sample, a gas meter(128) measuring the temperature of the sample, motor-operated valve(122) controlling the flow rate of the exhaust gas sample, a hydrostatic port(130) and a voltage port(140) to which the static pressure and voltage of the inhaled exhaust gas are respectively delivered, a static pressure sensor(135) measuring the hydrostatic of the exhaust gas, a differential pressure sensor(150) connected to the hydrostatic port and the voltage port to measure a dynamic pressure corresponding to a difference between the static pressure and voltage of the exhaust gas, a differential pressure correction(160) which selectively supplies the air and exhaust gas at fixed periods, and a controller(180) controlling the motor-operated valve.