SCHMIDT® Flow Sensor SS 20.700

Flow rates of gases – an important measurement in industrial processes.

 

  • "Heavy-Duty applications"
  • Double-pin sensor head, sensor elements completely encapsulated in stainless steel
  • For air and other gases in applications with harsh conditions (medium with aggressive components, contamination, high humidity)
  • Flow and temperature signal
  • Probe length of 250 or 600 mm
  • Remote sensor (optional)
  • Measuring ranges 0 … 10 m/s up to 0 … 220 m/s, special measuring range
  • Special gas adjustment for different gases (optional)
  • Pulse output
  • Grease free / O2 applications / PWIS-free (optional)
  • Pressure resistant up to 16 bar
  • Temperature range up to +120 °C
  • Module interface for expansion of sensor functions

 

The thermal SCHMIDT® Flow Sensor SS 20.700 is the perfect solution for extremely demanding industrial applications. It can be used for a diverse range of applications, such as compressed air monitoring, gas monitoring on process burners, consumption recording of gases and a great deal more.

 

Two specific versions „Oxygen O2 >21 %" and „Grease-free and Oxygen O2 >21 % (PWIS-free)" provide the required safety for applications with corresponding requirements.

 

The double-pin sensor head has been designed especially to meet the needs of so-called „heavy-duty applications“. Thanks to the sensor elements being completely encapsulated in stainless steel these are ideally suited for extremely demanding applications. The sensor is also resistant against aggressive media.

 

The SS 20.700 records flow velocity as well as media temperatures of up to 120 °C. It can be used in small tubes from DN40 upwards and can involve a sensor length of up to 600 mm to measure the volumetric flow rate in large channels and ducts. The sensor can be used in overpressure up to 16 bar.

 

This sensor is very easy to install: screw in the sensor using the compression fitting included, align the sensor in the gas flow and centrally in the pipe, connect it electrically – and job done!

 

The SS 20.700 operates without any moving parts and due to the measuring principle drifting or ageing do not play a role. This reduces the maintenance required for the sensor to an absolute minimum. Should cleaning nevertheless be necessary, it can be carried out very easily and in a variety of ways - simply the spirit of „heavy-duty“.

 

  • Heavy-Duty applications
  • Compressed air consumption measurement
  • Inert gas flow measurement
  • Flow rate control
  • Compressor control
  • Exhaust air monitoring
  • Control of the combustion air at block heating plants and fuel cells
  • Air mass flow measurement in burners and combustion engines

 

For calculations of measuring range with our flow calculator, please use settings for SS 20.600.

 

SCHMIDT Technology – Simply a question of better measurement

Specifications

Technical data
Measuring quantityStandard flow velocity wN based on standard conditions 1)
Temperature of medium TM
Measured mediumAir or nitrogen
Optional: Pure oxygen, argon, CO2, other gases on request
Measuring range wN0 … 10 / 20 / 60 / 90 / 140 / 220 m/s
Optional: Customised measuring ranges in steps of 1 m/s
Lower detection limit wN0.1 m/s
Measuring range TM-20 … +120 °C
Measuring accuracy
Standard wN±(3 % of measured value + [0.4 % of fmr; min. 0.08 m/s]) 2)
Response time (t90) wN10 s (jump of wN from 0 to 5 m/s in air)
Temperature TM (wN > 2 m/s)±1 K (10 … 30 °C); ±2 K (remaining measuring range)
Operating temperature
Sensor probe-20 … +120 °C
Electronics-20 … +70 °C
Storage temperature-20 … +85 °C
Material
EnclosureAluminium, anodised
Sensor tubeStainless steel 1.4571
Sensor headStainless steel 1.4404
Sensor cable (of remote probe)Jacket TPE, halogen free
Compression fittingStainless steel 1.4571, NBR (or FKM), depending on version
General data
HumidityMeasuring mode: Non-condensing (< 95 % RH)
Operating pressure (max.)16 bar (overpressure)
Display4 x Duo-LED (green/red/orange)
LED ring
Supply voltage24 V DC ± 20 %
Current consumptionTyp. 80 mA (without pulse outputs); max. 200 mA (excluding signal current of pulse output 2 [relay] and current consumption of extension module)
Analog outputs
Type: Auto U / I)
wN, TM
0 … 10 V / 4 … 20 mA (switching of signal characteristic depends on RL)
-Voltage output (0 … 10 V): RL ≥ 550 Ω (short-circuit protected)
- Current output (4 … 20 mA): RL ≤ 500 Ω
- Change-over hysteresis: 50 Ω
- CL ≤ 10 nF
Pulse outputs: SignalizationStandard: Frequency f ~ wN
f = 0 … fmax
fmax = 100 Hz (option: fmax = 10 … 99 Hz)
Optional: Pulse quantity:
1 pulse/1 m3; 1 pulse/0.1 m3; 1 pulse/0.01 m3 (max. 100 pulses/s)
Pulse outputs: Technology1. Highside-driver (PNP, open collector) at protected supply voltage; not galvanically isolated)
Short-circuit protected (analog): 100 mA
High level: > supply voltage - 3 V
Leckage current: IOFF < 10 µA
2. Semiconductor relay; output galvanically isolated
Output voltage/current: Max. 30 V / 50 mA
Electrical connectionMain: Plug-in connector M12 (A-coded), male, 8-pin (shielded), screwed
Module interface: Plug-in connector M12 (A-coded), female, 5-pin (shielded), screwed
Maximum cable lengthVoltage interface: 15 m
Current interface (pulse output): 100 m
Mounting positionArbitrary (exception: Temperature element may never be placed “above” heater element)
Mounting tolerance±3° relative to flow direction (uni-directional)
Minimum immersion depthDN40
Protection typeSensor probe: IP67; enclosure: IP65; electrical connectors: IP67 (with correctly attached cable)
Protection classIII (SELV or PELV)
Probe lengthCompact version: 250/600 mm
Remote version: Probe 250/600 mm
Remote cable: 1 … 10 m (step: 1 m)
WeightApprox. 500 g max.

1) Standard conditions: TN = 20 °C and pN = 1,013.25 hPa

2) Related to adjustment reference; "fmr" = final measuring range

Subject to technical changes.