KROHNE H54 M4 EN User Manual
Page 5
5 H54 Installation and operating instructions
1.3
Key for Pressure Equipment Directive
PED
/ / /
1 2 3 4 5
1 Pressure Equipment Directive
2
Fluid
G
Gases, liquefied gases, gases dissolved under pressure, vapors and those liquids
whose vapor pressure lies more than 0.5 bars over the normal atmospheric pressure
(1013 mbars) at the maximum permissible temperature
L
Liquids whose vapor pressure lies a maximum of 0.5 bars above the atmospheric
pressure at the maximum permissible temperature
3
Fluid group
1
Group 1:
Explosion-hazardous, highly flammable, readily flammable, flammable
(when the maximum permissible temperature lies above the flash point),
highly toxic, toxic, fire stimulating
2
Group 2:
All the fluids not specified in Group 1
4
Category
3.3
In accordance with Article 3.3 of Directive 97/23/EC
I
Category I to 97/23/EC
II
Category II to 97/23/EC
III
Category III to 97/23/EC
5
Conformity evaluation process
SEP
Solid
engineering
practice
A
Module A internal process inspection
A1
Module A1 internal process inspection with supervision of the acceptance
H
Module H Comprehensive quality assurance
The PED key marking is contained on the rating plate of the instrument.
1.4 Functional
principle
The flowmeter operates in accordance with the float measuring
principle.
A metal cone is installed in the measuring unit H54, in which
a suitably formed float can move freely up and down.
The flowmeter is inserted into a vertical pipeline and the
medium flows through it from bottom to top.
The guided float adjusts itself so that the buoyancy force
A acting on it, the wave resistance W and its weight G are
in equilibrium (G = A + W).
An annular gap which depends on the flow rate results.
The height of the float in the measuring unit, which depends
on the flow, is transmitted by a magnetic coupling and
displayed on a scale. Strong magnetic fields can lead to
deviations in the measured value.
The installation of several instruments in immediate vicinity to
each other does not cause notable influences.