Burkert 8745 MFC Ethernet, Руководство по эксплуатации

Страница: 28 / 70

28
Technical data
Type 8745 Ethernet, 8745 Analogue
6.7.4 Quality of the operating fluid
Use the operating fluid that is given on the product Type-label.
The operating fluid must be clean and dry.
The gas or gas mixture must obey the quality criteria
in Tab. 19. The quality criteria are given in standard
ISO 8573-1, Compressed Air - Part 1: Contaminants and
purity classes. The operating gas must obey the quality
criteria to obey the following requirements:
•
the necessary measurement accuracy of the product
•
to meet the safety requirements
•
to meet the closed-loop control accuracy of an MFC
For further information on the quality criteria, refer to
ISO 8573-1.
Tab. 19: Quality criteria of the fluid
Criteria Quality class Value
Maximum particle size 2 1 μm
Maximum particle density 2 1 mg/m³
Maximum dew point under
pressure
4 3 °C
Maximum oil concentration 1 0.01 mg/m³
6.8 Pressure loss (MFM)
A Mass Flow Meter has a pressure loss that depends on the fol -
lowing parameters:
•
the flow rate value
•
the size of the product fluid-connections
•
the type of the product fluid-connections
•
the size of the product base-block
•
the type of operating gas
→ Determine the pressure-loss value depending on whether the
operating fluid is air or a gas other than air.
6.8.1 Operating gas is air
If the operating gas is air, then read the pressure-loss value
directly from the diagrams in Fig. 13 or in Fig. 14.
For example, if the flow rate through an MFM with 1/2" threaded
fluid-connections is 1400 l
N
/min then the pressure loss for air, as
given in Fig. 13 , is 140 mbar.
English