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PREM - electromagnetic flow transducers

Purpose

PREM electromagnetic flow transducers are intended for transducing volumetric flow rate and volume of conducting liquids to indications, recording of measurement results and transmitting these to peripheral devices (heat calculation units, regulators, centralized control devices and other secondary instruments).

Application field Transducers can be used on heat and power industry objects, industrial enterprises as well as housing and public utility sector.
Product features

General

  • Three configuration classes with different dynamic ranges B1, C1, D;
  • Different dynamic ranges in forward and backward direction;
  • Pulse-count outputs have several modes (reversing, accounting for flow direction, comparator, indicator of measurement error) which are set when device is ordered; by default reversing mode is set.

Design

  • Features sandwich or flanged;
  • Arrow on the housing indicating forward direction of the flow;

Protection against unauthorized interference

  • Hardware protection from unauthorized change of calibration factors;
  • Restricted access to change of setup variables;
  • Pulse weight is fixed (set by manufacturer when device is ordered).

General technical specifications

Performance characteristics

PREM transducers are used for measuring volume flow rate of water and other homogeneous liquids with specific electrical conductivity from10-3 to 10 S/m.

PREM transducers are inteded for use under exposure of the following external factors:

  • Measured medium non-aggressive to pipe internal finishing material (F4 fluoroplastic) and electrodes material (steel 121810);
  • Temperature of the measured medium within the range from 0 to +150°C;
  • Environmental temperature from -10 to +50°C;
  • Working pressure of the measured medium up to 1.6 MPa.

Transducers are powered from DC mains with nominal voltage 12 V and power 5 W.
Minimum length of straight piping section upstream and downstream the transducer shall be 2 DN.

Metrologic characteristics

Nominal inside diameter (DN) of transducers and corresponding maximum flow rate values  (Qma) regardless of the direction of measured media flow corresponds to values provided in Table 1.

Table 1

DN, mm

Qmax1

Qmax2 *

20

12

6.0

32

30

15

40

45

22.5

50

72

36

65

120

60

80

180

90

100

280

140

150

630

315

* - on Customer's request (corresponds to flow rate 5  m/s).

Transition (Q1, Q2) minimum (Qmin) flow rate values depending on transducer class and direction of measured media flow are determined from proportions indicated in Table 2.

Table 2

Class

Flow rate values depending on the flow direction of the measured media

backward direction

forward direction

backward direction

forward direction

backward and forward

Qmin

Qmin

Q2

Q2

Q1

B1

-

Qmax1/625

Qmax1/150

Qmax1/450

Qmax1/100

C1

-

Qmax1/625

Qmax1/150

Qmax1/250

Qmax1/100

D

Qmax1/375

Qmax1/375

Qmax1/150

Qmax1/150

Qmax1/100

Limits of permissible relative error of transducing flow rate and volume to pulse and digital signals as well as during indication of measured values through display depending on measurement range correspond to values indicated in Table 3.

Table 3


Class

Limits of error within flow rate measurement range, %

Q()min…Q()2

Q()2…Q1

Q1…Qmax1(2)

1, 1, D

± 5.0

± 2.0

± 1.0

Output signals:

  • One or two pulse-count signals;
  • Current signal within current variation range (4-20) mA proportional to the flow rate measured;
  • Digital signal in RS485 or RS232 interface standard.

Warranty period

Transducer warranty period - 4 years.