Flowserve NRG 16-38S - Manual (Page 10)

10
Explanatory Notes
– continued –
Function
Designs
Water level limiter NRG 16-11
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
monitored is required (at least 10 µS / cm at 25 °C).
The relay de-energizing delay is 15 sec.
Level monitoring NRGT 26-1
The principle of capacitance measurement is applied to determine the liquid level.
The electrode rod and the vessel wall form a capacitor. If the level of the dielectric
located between the two capacitor plates changes, the current which flows through
the plates changes proportionally to the level. A dielectric is defined as an insulating
substance, which excludes many liquids such as water. In order to receive a useful
measuring result the measuring rod, which is completely submerged in the liquid,
must be completely insulated. After calibrating the zero point/measuring range
(0%/100%) of the electronic control unit, the level can be read off from a remote
display unit. The level measuring range (control range) can be changed during
operation.
■ NRG 16-38 S
1 Level electrode NRG 16-11
1 STARLOCK
® retaining ring 11.5/4.8
1 Level electrode NRGT 26-1
Both level electrodes are installed together in one flange DN 100, Fig. 1
■ NRG 16-39 S
2 Level electrodes NRG 16-11
2 STARLOCK
® retaining rings 11.5/4.8
1 Level electrode NRGT 26-1
All level electrodes are installed in one flange DN 150, Fig. 2
System components
NRS 1-7
Control unit for low-level sensing electrode NRG 16-11 (M
IN
alarm) designed to use
in conjunction with level electrodes NRG 16-38 S and 16-39 S.
Function: Signalling of low-level alarm
STARLOCK ® is a registered trademark of Gebr. Titgemeyer GmbH & Co. KG, Osnabrück