Flowserve NRGS 11-2 - Manual (Page 5)

5
Explanatory Notes
continued
System description
The compact system NRGS -2, NRGS 6-2 works according to the conductivity measurement prin-
ciple. With the NRGS -2, NRGS 6-2 a maximum of 3 levels can be signalled in conductive liquids:
■
Low level alarm, pump ON, pump OFF with a normally open contact
The NRGS -2 / NRGS 6-2 has its level switch integrated in the electrode case for the control of all
functions. An external switching device is not required.
The NRGS -2 / NRGS 6-2 has two electrode tips for the detection of low water level. The signalling
of the low-level alarm is effected via two separate switching channels.
Function
The conductivity of the liquid is used to signal the liquid level. Some liquids are conductive, which
means that they allow an electric current to flow through them. For the safe functioning of this device
a minimum conductivity of the liquid to be measured is required.
The conductivity measurement method can detect two conditions: electrode tip submerged or ex-
posed, meaning switchpoint reached or not reached. Before installation, the length of the electrode
tip must be cut to the required switching levels, e. g. for max./min. alarm, controlling of a valve or
pump.
Designs
NRGS 11-2: Screwed design " BSP, EN ISO 228-, PN 6.
NRGS 16-2: Screwed design " BSP, EN ISO 228-, PN 40. Fig. 1
NRGS 11-2, NRGS 16-2
Technical Data
Type approval n°
TÜV · WR/WB · 02-392
Max. service pressure
NRGS -2: 6 bar g at 59 °C, NRGS 6-2: 32 bar g at 238 °C
Connections
Screwed ", EN ISO 228-
Materials
Terminal box
Die cast aluminium 3.26 G AlSi8Cu3
Stem S.S. .457 CrNiMoTi7-2-2
Housing .457
Flange Forget steel .0460 C22.8
Measuring electrodes S.S. .457 CrNiMoTi7-2-2
Electrode insulation PTFE
Spacer disc
PTFE