03/12
Electromagnetic
Flow Switch and Flow Meter
Installation and
Operating
Instructions
DWM 1000
DWM 2000
DWM 2000 L
DWM 2000 IP68
KROHNE
CERTIFIED
ISO
9001
S.A.
Contents
Page
Introduction.....................................................3
Special Features
Measuring Principles
Components
Installation.......................................................4
Mounting on Pipeline
Dimensions and Weight
Electrical Connection and Settings
DWM1000................................................5
DWM2000................................................6
Compatible Relays (for DWM1000)...........7
Version DWM2000 IP68.............................8
Version DWM2000 Long
Characteristics ........................................8
Components............................................8
Installation................................................9
Trouble Shooting............................................10
Technical Data................................................11
KROHNE Contact Addresses.....................12
2
3
DWM Flow Meters and Switches
The DWM electromagnetic flow meters and switches are
desi
gned to measure and monitor the flow rates of
e l e c t r i c a l l y c o n d u c t i v e l i q u i d s , p a s t e s a n d
s l u r r i e s
Versions
DWM 1000 flow switch, 2-wire
DWM 2000 flow meter, 4-20 mA current
DWM 2000 L (Long) for flow pipes of greater than 400m
DWM 2000 IP68 for immersed
DWM 2000 FT for food applications with
Special
Rugged design, IP55 protection, equivalent to NEMA 4
All wetted surfaces of ceramic, stainless steel and
Compatible with process temperatures up to 150°C
Suitable for operating pressures up to 25 bar
No moving parts, maintenance
Electronic unit replaceable without interruption of
Compatible for al l pipelines with nominal diameter
Readout connection possible with handheld consoles
system.
dia
meter or open
Tuchenhagen
instructions
Features
and
4X
standards.
platinum.
(300°F),
(DN)
(DWM
Measuring
If an electrical conductor moves through a magnetic field,
voltage,U, is induced in the conductor. In the case of
DWM, the liquid in the flow pipe is the electrical
In the diagram below, the DWM creates the magnetic
B, perpendicular to the direction of flow. The induced
ge U is directly proportional to the local flow velocity v.
U = k x B x v x D k - Instrument
Voltage U is tapped of f from the electrodes, neutral
ground electrode (connection
DWM 1000 Flow Switch - Voltage U is converted into a
switching signal with adjustable switching
DWM 2000 Flow Meter - Voltage U is converted into a
proportional output signal current between 4-20 mA
independant).
and ambient temperatures between - 25 à +
50mm
2000
Principle
channels.
connection (detailed in a separate
leaflet).
(2”).
only).
B - Strength of magnetic
v - Flow
D - Electrode
velocity
socket)
output/readout.
applications.
free.
constant
spacing
point.
(360psi).
field
60°C
flow.
the
conductor.
field,
volta-
and
flow-
(load
a
Components of DWM
1 Connection
2
Gasket
3
Sensor
4 Threaded Connection
5 Earthing
6 Earth Clamping
7 Cable Entry Gland M20x1.5
8
Housing
9 Blanking
10 Supply
11 Connection
12 Magnetic Coils and Electrode
13 Electronic
14 Cover
15 Cover With Fitted
Socket
Cable
Plug
Terminals
Unit
Screws
1000/2000
Strap
Chamber
Gasket
(1")
Contacts
4
M20 x 1.5
Installation
Mounting onto the
The DWM should be mounted onto the pipeline (nominal diameter (DN) 50mm (2") by means of the connection socket
provided.
Refer to the diagrams below for the orientation and positioning of the connection socket. The socket should be inserted as
far
as
depth of insertion so that the protrusion of the probe is 1/8 of the true internal diameter (i.e. not the
The location hole in the pipeline should be drilled to a diameter of 39 mm (1.54") with a maximum of 0.5 mm play between
the
socket and bore. Secure the socket perpendicular to the pipe with four spot welds, then carry out an unbroken weld of the
entire
The straight line flow distance required between the DWM and an upstream flow disturbance (inlet, pump, elbow etc) is
advised
The DWM must be installed into the socket using the supplied gasket, which ensures water tightness and flush positioning of
the
ceramic probe head. Teflon tape should not be used on the thread as this insulates the required earthing contact, and
pre
vents from correct protrusion of the probe.
Only the electronics unit must be rotated according to the flow direction (see “Electrical Connection and
pipeline
the corresponding pipeline diameter (DN) marking. In case there is pipe insulation, it is necessary to calculate
diameter, with an electrode of 1.2mm diameter and setting of 90 to
to be 10 x DN and 5 x DN from downstream
DN).
150A.
disturbances.
Setting”).
Installation on plastic p
In the case where the unit is to be installed on a plastic flow pipe, it is necessary to assure an earth connection. In all cases
KROHNE to ensure an effective
ipes
solution.
Welding
Socket
Correct
Incorrect
the
consult
Dimensions and Weight
Diecast aluminium housing - weight excluding socket approx. 1.85Kg
DWM1000
DWM2000
(4.08lbs)