KROHNE DW 181-182-183-184 EN - Manual (Page 9)

Installation and operating instructions DW 181 - 184 9
1 Mechanical Installation
1.1 Positioning the flow switch
No obstacles along the pipe within five diameters (D) upstream and two diameters downstream of
the instrument.
1.2 Installation in hazardous areas (Ex applications)
Read all instructions referring to flow switches in hazardous locations before installation.
Check that the flange, gasket and other materials in contact with the product are compatible. Refer
to the information given on the converter nameplate, the flange markings and specifications given
in the ATEX approval certificate.
1.3 Connecting the DW 18 to the pipe
• Before installation, clean the piping to remove any dust or weld debris.
• Fit the instrument on the pipe with the arrow on the housing pointing in the direction of flow.
• Flange connections: ensure that the gaskets are in place, flange facings are aligned and parallel
and that the bolts have been tightened with the amount of torque specified in European or local (if
outside the E.U.) standards.
1.4 Flow direction
The DW 183 and DW 184 can be installed in any position on the piping. However, the position of
installation and the flow direction must be indicated in the customer order (i.e. up, down, left to right
and right to left) as the weight of the baffle disc is taken into account when calibrating the
instrument. Flow direction must be indicated for DW 181 and DW 182 instruments equipped with
type A indicators.
The DW 184 is used for high-velocity or turbulent flows in pipes with diameters greater than
DN250. A special device, called a stilling well, is immersed in the liquid flow and channels the fluid
through a tube in which the disc moves, secured to the end of a rigid support. This reinforced pivot
enables the flow switch to be used in difficult conditions.
These instruments are only supplied with an index display (indicator type “G”) and switches. They
are not equipped with a graduated dial. The heights of the connection piece indicated for the
production of the mating flange must be respected.