SCHMIDT® Flow Switch SS 20.200

Thermal Flow Switch for monitoring the flow rate of air and gases. Patented sensor head, largely independent of flow direction and dirt-resistant. Visual indicator of switching and operating status. Increased resistance to media with optional protective coating.

 

  • Dumb-bell head (largely independent from flow direction, easy to clean)
  • Flow switch
  • Probe length 100 … 500 mm
  • Measuring ranges 0 … 1 m/s to 0 … 20 m/s
  • Potentiometer (pre-programmed as option)
  • Optional coated

 

  • Exhaust air monitoring system
  • Filter monitoring
  • Cooling air monitoring
  • Fume cupboards
  • Workplace exhausts
  • Semiconductor process equipment

 

SCHMIDT® Technology - simply a question of better measurement

Specifications

Technical data
Measuring quantityStandard flow velocity wN, based on standard conditions 1)
Measured mediumAir, nitrogen, other gases on request
Measuring range wN0 … 1 / 2.5 / 10 / 20 m/s
Lower detection limit wN0.06 m/s
Threshold wN5 … 95 % of measurement range (min. 0.1 m/s)
Threshold setting wNPotentiometer (270°)>br>Optionally pre-programmed by factory (potentiometer deactivated)
Measuring accuracy
Switching hysteresis wN± 5 % of threshold value; min. 0.1 m/s
Threshold pre-programmed wN± 3 % of measuring value + 0.1 m/s
Response time (t90) wN3 s (jump of wN from 0 to 5 m/s in air)
Switch-on delay20 s
Temperature gradient wN< 2 K/min (at wN = 5 m/s in air)
Operating temperature
Sensor- 20 … + 85 °C
Electronics- 20 … + 70 °C
Storage temperature- 20 … + 85 °C
Material
HousingPBT, fibre-glass reinforced
Sensor tubeStainless steel 1.4571
Sensor headPBT, fibre-glass reinforced, stainless steel 1.4571
Protective coatingPolyurethane derivative (optional)
Sensor cablePVC
General data
HumidityMeasuring mode: Non-condensing (< 95 % RH)
Operating pressure (max.)0 … 10 bar (overpressure)
DisplayLED green: operating status;
LED red: switching status
Supply voltage24 V DC ± 20 %
Current consumptionTypical 40 mA (max. 70 mA, without signal current of relais output)
Switching outputSemiconductor relais; max. 30 V / 100 mA / 300 mW RON,max = 25 Ω
Electrical connectionNon-detachable cable, 4 wires, length 2 m
Maximum cable length100 m max.
Mounting positionArbitrary
Minimum immersion depth58 mm (< 58 mm on request)
Protection type / classHousing: IP65 (with installed rubber plug), sensor head: IP67 / III or PELV (EN 50178)
MTTF value (per 01.01.2011)> 50 years
Probe length100 / 200 / 350 / 500 mm
WeightApprox. 100 g (L = 350 mm)

1) Standard velocity wN based on standard conditions of 20 °C and 1,013.25 hPa, related to adjustment reference; fmr = final measuring range

Subject to technical changes.

Order information

 DescriptionArticle-Number
Basic sensorSCHMIDT® Flow Switch SS 20.200; without protective coating504 475 -XYSN xx
SCHMIDT® Flow Sensor SS 20.200; with swichting output, cable length 2 m, with protective coating505 504 -XYSN xx
 Options
Mechanical TypeSensor length 100 mm 1   
Sensor length 200 mm 2   
Sensor length 350 mm 3   
Sensor length 500 mm 4   
Measuring rangeMeasuring range 0 … 1 m/s  1  
Measuring range 0 … 2.5 m/s  2  
Measuring range 0 … 10 m/s  3  
Measuring range 0 … 20 m/s  4  
Signalization relais/LEDFlow velocity wN above switching threshold: relais closes / LED on   1 
Flow velocity wN above switching threshold: relais opens 1) / LED on   2 
Flow velocity wN below switching threshold: relais closes / LED on   3 
Flow velocity wN below switching threshold: relais opens 1) /LED on   4 
Setting thresholdWith setting potentiometer, without pre-setting    P 00
With setting potentiometer, selectable pre-setting from 5 up to 95% of measuring range    P 05 … 95
Selectable pre-programming (not changeable) from 5 up to 95% of measuring range    F 05 … 95

1) The configuration “open relay” in case of an alarm is called a “fail-safe” because both a power failure and a cable break can be signalized as an alarm as well.

Accessories

Connection technology

DescriptionArticle-Number
Power supply 24 V/1 A DC (output), 115/230 V AC voltage supply535 282

Mounting and fixing technology

DescriptionArticle-Number
Mounting flange made of galvanized steel301 048
Wall mounting flange stainless steel, PTFE clamp ring520 181
Compression fitting stainless steel G½, atmospheric pressure532 160
Compression fitting brass G½, atmospheric pressure517 206
Compression fitting stainless steel G½, max. 10 bar, with protection against pressure losses524 919
Compression fitting brass G½, max. 10 bar, with protection against pressure losses524 891
Welding sleeve steel G½, according to EN 10241, 5 pieces524 916
Welding sleeve stainless steel G½, according to EN 10241, 2 pieces524 882

Miscellaneous

DescriptionArticle-Number
Clip-on bars for protection of sensor head against mechanical impacts, stainless steel531 026
Attachable 2-wires-clip for protection of sensor head against mechanical impacts, stainless steel, H2O2-resistant559 124

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