Liquid Level Switch
Typ: NWS

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.

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Details

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

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