KROHNE DWM1000, DWM-2000 User Manual

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)