Page 4
007-03-004 Issue D
www.skcltd.com
Introduction to the chek-mate Flowmeter
The chek-mate flowmeter is designed specifically for use in the occupational health and
safety industry for the purpose of calibrating the air flow rate into air sample trains. Its flow
range makes it suitable for use across a broad range of air sampling methods and with a
broad range of air samplers, sample media and air sample pumps.
Operating Principle
The chek-mate is an orifice type flowmeter. Its reading is determined by measuring the
pressure drop across the orifice caused by the flow of air through the orifice, using a
differential pressure sensor. This type of flowmeter gives a mass flow reading meaning
that the pressure drop across the orifice will be constant for a given mass flow of gas
independent of the density of the gas.
The chek-mate also incorporates an ambient temperature sensor and an atmospheric
pressure sensor and uses the readings of these sensors to correct the mass flow reading
generated by measuring the pressure drop across the orifice to the current ambient
temperature and atmospheric pressure. This correction provides an indicated flow reading
that is equivalent to a volumetric flow reading when the inlet of the flowmeter is open to
atmosphere.
CalChek Pump Calibration
The 375-0550 chek-mate model incorporates a CalChek serial interface which enables it to
communicate directly with SKC AirChek 2000, AirChek 3000 and AirChek Touch pumps, in