Heinrichs Messtechnik GmbH • Robert-Perthel-Straße 9 • 50739 Köln • Tel.: +49 (221) 49708-0 • info@heinrichs.eu
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Liquid Level Switch
- Measuring length up to 4000mm
- Level indicator in percent, 4-20 mA analogue output
- Four devices for various applications
- For ATEX applications
The KOBOLD liquid level switch NWS is designed as a 2 and 3-wire switch and can be universally used in vessels and pipelines. The NWS operates on the tuning fork principle in air at resonance frequency. A piezoelectric crystal is used for excitation of oscillations and for monitoring the actual oscillation frequency.
When the fork is immersed in liquid, the frequency changes: this change is detected electronically and the output signal is changed. The NWS operates as a 2-wire switch in series with the load. The simple electronic switch is operated by the liquid. The NWS can also be connected to a PLC through a third terminal.
Applications
- Oils and foamed olis
- Water
- Paints and transparent inks
- Sauces
- Milk
- Liquids containing carbon dioxide
The KOBOLD NWS is ideal for hygienic and sterile applications and for CIP cycles up to 150 °C.
Technical data
Material
Fork: stainless steel 1.4404
Process connection: stainless steel 1.4404
Electronic housing:
- NWS-… 200: PAG, glass-fibre- reinforced cover with window, 330° rotatable
- all other types: stainless steel 1.4301
Process connections:
- pipe thread DIN EN 10226-1
- NPT-thread
- Tri-Clamp®
- pipe connection DIN 11851 (sanitary connection)
- aseptic-connection DIN 11864
- DRD flange
- Flange B 25 PN 40 DIN 2527
- Flange B 50 PN 40 DIN 2527
- Flange ANSI B 16,5 – 1″, 300 lbs
- Flange ANSI B 16,5 – 2″, 300 lbs
Ingress protection:
- plastic housing: IP 65 (NWS-… 200)
- stainless steel housing
- plug connection: IP 67
- cable connection: IP 68
Max. Max. operating pressure: 45 bar flange connection: see pressure steps
Max. Temperature of medium:
- -20 … 130 °C (NWS-… 200…)
- -20 … 90 °C (or all other NWS)
- short-time 150 °C for CIP (valid for all models NWS)
Min. medium density: 800 g/l
Ambient temperature: -20 °C … +70 °C
Min. immersion depth for switch points: 12 mm (marker on fork)
Power supply:
- NWS-… 200..:
- .. 240 V DC/AC (50/60 Hz)
- 2-wire; 24 V DC, 3-wire
- NWS-… 23/24:
- 24 VDC, 3-wire
- NWS-… 2E … (ATEX): Isolation Switching Amplifier to IEC 60947-5-6 (Namur) necessary
Delay:
- 1 s wet /dry
- 1 s dry / wet
Viscosity: 5000 mm2/s max. at 25 °C (influence on the response time)
Hysteresis: 4 mm vertical, 1 mm horizontal
Repeatability: ± 1 mm
ATEX / IECEx-version
- Type of protection: intrinsically safe ia
- Designation:
- Ex II 1G Exia IIC T6 Ga
- IECEx Exia IIC T6 Ga
- To use in connection with intrinsically safe Isolation Switching Amplifier according to IEC 60947-5-6
