Page 409 - Bürkert

Mass Flow Meter (MFM) for Gases

8701 • Direct flow measurement for nominal

flow rates from 10 mlN/min to 80 lN/
min (N2) in MEMS technology

• High accuracy
• Short response time
• Optional Fieldbus

Mass flow meters are used in process technology for the direct measure- Dimensions [mm] (see datasheet for more details)
ment of the mass flow of gases. In case of volumetric flow meters, it is
necessary to measure the temperature and the pressure either the den-
sity, because gases change their density or rather their volume depend-
ing on the pressure. The measurement of the mass flow, on the other
hand, is independent on pressure and the temperature. A
The digital mass flow meter, Type 8701, uses a sensor on silicon chip ba-
sis (see the description on page 2) located directly in the bypass channel.
Due to the fact that the sensor is directly in the bypass channel a very
short response time of the MFM is reached. The actual flow is given as A
an analog output signal or could be read out over RS communication.
Type 8701 can optionally be calibrated for two different gases, the user B
is able to switch between these two gases. The materials of the parts that
come into contact with the medium are selected according to customer
specification so that the unit can be operated with the complete range of
standard process gases.
Typical application areas are gas flow measurement in
• Test benches
• Environmental technology
• Medical technology and
• Analytical instruments
• C
Note: With the free downloadable communication software, numerous other functions can be
programmed. To do this, the MFC / MFM should connected via an adapter to a computer.
Technical Data A B C
107 28 115.5
2)
Nominal flow range (Q ) 10 ml /min to 80 l /min (N ),
1)
nom N N 2
Span 1:50 (2-100%), (higher span on request)
Operating medium Neutral, non-contaminated gases, (others on request)
Calibration medium Operating gas or air with correction function
Max. operating pressure 10 bar (145 psi)
(Inlet pressure)
Medium temperature -10 ºC to +70 ºC (-10 ºC to +60 °C with oxygen)
Ambient temperature -10 ºC to +50 ºC
Measuring accuracy ±0.8% o. R. (of reading)
(after 1 min. warm up time) ±0.3% F. S. (of full scale)
Repeatability ±0.1% F.S. (of full scale)
Response time (t 95% ) < 300 ms
Materials
Body Aluminium or stainless steel
Housing PC (Polycarbonate) or metal
Seals FKM, EPDM
Port connection G 1/4”, others on request
Electr. connection Plug D-Sub 15-pin
Additionally with Fieldbus: with PROFIBUS DP: Socket M12 5-pin
with DeviceNet/CANopen: Socket M12 5-pin
Power supply 24V DC
Voltage tolerance ±10%

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