Azbil Micro Flow MQV9005 - Relationship between Differential Pressure and Flow Rate

7-10
Chapter 7. SPECIFICATIONS
*1. The notations mL/min (standard) and the L/min (standard) refer to volumetric flow rate per minute after conversion to
20°C , 101.325 kPa (1 atm). The reference temperature can also be changed to 0°C, 25°C or 35°C in the
C- 19
flow rate
display unit selection. The controllable flow rate range varies according to the gas type.

Gas type and control
range (P.7-11)
*2. For natural gas 13A, the device is calibrated based on the two types of gas listed below. (Changes can be made using
the keys.) If a gas other than these types are used, please contact Azbil Corporation.
Gas type (using Azbil
Corp. terminology)
Calorific value in
MJ/m
3
(N)
Methane (%) Ethane (%) Propane (%) Butane (%)
Natural gas 13A-46MJ 46.04655 88 5.8 4.5 1.7
Natural gas 13A-45MJ 45.007 88.9 6.8 3.1 1.2
*3. For air/nitrogen and oxygen (for the oxygen model). For details about accuracy for other gas types, please contact Azbil.
Also, analog output accuracy (± 0.3 %) is not included in the control accuracy.
*4. Differential pressure required for obtaining full-scale flow rate. (Outlet pressure=0 kPa (gauge))
*5. Operation is possible even below the required differential pressure, but the controllable flow rate range becomes
narrower.

Relationship between differential pressure and flow rate (P.7-12)
*6. For the advisability of using an inlet pressure of 0.5 MPa (gauge) or more, contact the azbil Group.
*7. The MLP100 Loader Package for the MQV is required (sold separately).
*8. Only models with RS-485 communications option.
*9. The maximum operating differential pressure of the MQV0200/0500 may also vary depending on the power voltage. For
details, see the graph below.
Relationship between power voltage and maximum operating differential pressure in MQV0200/0500
21.0
140
160
180
200
220
240
260
280
300
22.0 23.0 24.0 25.0 26.0 27.0
25 °C
40 °C
60 °C
Power voltage [V]
Maximum operating dierential pressure [kPa]
MQV0200 MQV0500
Handling Precautions
•
If this device is operated with a differential pressure exceeding the maximum
operating differential pressure shown in the graph on the preceding page, the
voltage to the valve becomes insufficient and the target flow rate cannot be
obtained. Additionally, even if the voltage does not become insufficient, flow
rate hunting may occur if the operating differential pressure exceeds 300 kPa.
Always operate this device with a differential pressure less than 300 kPa.
21.0
140
160
180
200
220
240
260
280
300
22.0 23.0 24.0 25.0 26.0 27.0
25 °C
35 °C
50 °C
Power voltage [V]
Maximum operating dierential pressure [kPa]