
BGN
Page 7 BGN K01/0908
The limit values for temperature and air humidity at the
mounting location must be maintained. Avoid corrosive
atmospheres. If this cannot be avoided, ventilation must be
installed.
Please make sure that there is adequate clearance from
parts that might cause magnetic interferences such as
solenoid valves and ferromagnetic components like steel
brackets/supports. We recommend that the minimum lateral
distance between two adjacently mounted devices be
300 mm. The devices can be mounted close together if
vertically offset by one device length. The minimum lateral
clearance for interfering steel parts should be 200 mm. In
case of doubt, check the interference by moving the device
back and forth in the selected distance by about 200 mm
and testing whether the pointer position changes.
Select the mounting location so as to enable a reliable
reading of the scale values. Please take note as well of the
space requirement for any possible disassembly of the
device. As a rule, inlet and outlet sections in front of and
behind the device are unnecessary if the medium has a
linear flow profile. Avoid mounting accessories converging
on one side in front of the device. However, if this is
indispensable maintain a minimum device length of 250 mm
as an inlet section.
The nominal size of the pipes to be connected must
correspond to that of the meter. Avoid fittings converging on
one side directly in front of the device. As a rule, install
valves behind the measuring equipment if there are gases
involved.
7.1.1 Mounting/start-up
The device must be mounted in accordance with the
direction of flow from the bottom to the top (perpendicularly).
Please observe the prior reference to the BGF-type device.
The nominal size of the device and that of the pipes must be
the same. The pressure stages and, hence, the dimensions
of the flanges must coincide. The surface roughness of the
flange sealing surface must be suitable for the prescribed
gaskets.
Please check whether possible accessories like spring
stops, gas/liquid-type dampers are still correctly sitting on the
flange. Check whether the mounting clearance between the
flanges of the pipes corresponds to the assembly dimension
of the device plus two gaskets. To achieve stress-free
mounting, the flanges of the pipes must be aligned parallel to
each other.
Use connecting bolts and gaskets in the prescribed
dimensions. The gaskets must be suitable for the operating
pressure, the temperature and the measured medium. With
PTFE-coated devices, use gaskets whose interior and
exterior diameter correspond to the sealing strip of the
device.
Tighten the screws crosswise so that the process
connections are tight. See to the tightening torques of
screws especially with PTFE-coated devices.
The maximum torques for PTFE-coated devices are:
DN15/DN25 = 14 Nm/DN50 = 25 Nm/DN80 = 35 Nm/DN100
= 42 Nm (following VDI/VDE Guideline 3513).
Please check whether the pipe is adequately stable to rule
out the possibility of vibration or swinging of the device. (Do
not use steel mounting parts on the device.)
When gas is used as the medium, pay special attention to
the position of the valve. If the device is calibrated to more
than 1.013 bars absolute pressure, the valve is usually
installed behind the flowmeter. At 1.013 bars absolute
pressure (free exhaust) install it in front of the device.
If there is risk of dirt or solid matter penetrating the process
pipes, flush them beforehand so that these materials do not
get caught in the device. Ferromagnetic solid matter such
as spatter can lead to the breakdown of the device. If these
materials are still present during normal operating
conditions, mount a magnetic filter (accessory) in front of the
device. When using liquids, flush to avoid a surge of gas
bubbles. Slowly increase the supply pressure when using
gases to prevent pressure surges. Basically, avoid
activation using solenoid valves to prevent the float from
shooting upwards.
7.1.1.1 Gas measurement
When using gases, slowly let the operating pressure rise. At
the same time, vary the operating pressure through a setting
valve so that the float is not knocked around since otherwise
this would damage the measuring element.
7.1.2 Device settings
The measuring equipment is delivered ready for operation
according to your order specifications. The limit
transducers are set to the desired values. If you have
submitted no requirements, the basic setting for
1 contact device: - Minimum contact switching point at 10 %
of descending flow (damped/closed-circuit principle).
2 contact devices: Minimum contact switching point at 10 %
of descending flow and maximum contact switching point at
90 % of ascending flow.
7.1.3 Adjusting the limit transducer
The contacts are adjustable through the contact position
indicators located on the scale. Dismantle the indicator
cover, unfasten the contact position indicators, set to the
desired value and reattach them.