SCHMIDT® Flow Sensor SS 23.700 Ex

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
PWIS-conform (optional)
Pressure resistant up to 16 bar
Temperature range from -20 °C up to +120 °C
ATEX (optional):

- Gases, zone 2: II 3G Ex ec ic IIC T4 Gc

- Dust, zone 22: II 3D Ex ic tc IIIC T135°C Dc

Finalist - Best of Industry Award 2024 in the category process industry - process instrumentation

The SCHMIDT^® Flow Sensor SS 23.700 Ex 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.

The order option "PWIS-conform" provides 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 23.700 Ex records flow velocity as well as media temperatures from -20 °C 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 23.700 Ex 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 quantity	Standard flow velocity w_N based on standard conditions ¹⁾ Temperature of medium T_M
Measured medium	Air or nitrogen Optional: biogas, methane, natural gas, argon, CO₂, special gases and mixtures and others (on request)
Measuring range w_N	0 … 10 / 20 / 60 / 90 / 140 / 220 m/s Optional: Customised measuring ranges in steps of 1 m/s
Lower detection limit w_N	0.1 m/s
Measuring range T_M	-20 … +120 °C
Measuring accuracy
Standard w_N	±(3 % of measured value + [0.4 % of fmr; min. 0.08 m/s]) ²⁾
Response time (t₉₀) w_N	10 s (jump of w_N from 0 to 5 m/s in air)
T_M (w_N > 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
Housing	Aluminium, anodised
Sensor tube	Stainless steel 1.4571
Sensor head	Stainless steel 1.4404
Sensor cable (remote sensor)	Jacket TPE, halogen-free
Compression fitting	Standard: Stainless steel 1.4571, FKM PWIS-compliant: Stainless steel 1.4571, coating DurniCoat (NiP)
General data
Humidity	Measuring mode: Non-condensing (< 95 % RH)
Operating pressure (max.)	16 bar (overpressure)
Display	4 x Duo-LED (green/red/orange)
Supply voltage	24 V DC ± 20 %
Current consumption	Typical 80 mA (without pulse outputs); max. 200 mA (excluding signal current of pulse output 2 [relay])
Analog outputs Type: Auto U / I)	w_N, T_M 0 … 10 V / 4 … 20 mA (switching of signal characteristic depends on R_L) -Voltage output (0 … 10 V): R_L ≥ 550 Ω (short-circuit protected) - Current output (4 … 20 mA): R_L ≤ 500 Ω - Change-over hysteresis: 50 Ω - C_L ≤ 10 nF
Pulse outputs: Signalization	Frequency: w_N ~ f = 0 … f_max; f_max = 10 … 100 Hz Optional: 1 pulse/1 m³; 1 pulse/0.1 m³; 1 pulse/0.01 m³ (max. 100 pulses/s)
Pulse outputs: Technology	1. 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: I_OFF < 10 µA 2. Semiconductor relay; output galvanically isolated Output voltage/current: Max. 30 V / 50 mA
Electrical connection	Plug-in connector M12 (A-coded), male, 8-pin (shielded), screwed ATEX approval only in combination with original cable!
Maximum cable length	Voltage interface / current interface / pulse outputs: 100 m Voltage mode: Use AGND and R_L ≥ 10 k (mass offset)
Mounting position	Arbitrary (exception: Temperature element may never be placed “above” heater element)
Mounting tolerance	±3° relative to flow direction (unidirectional)
Minimum immersion depth	DN40
Protection type	Sensor probe: IP67; enclosure: IP65 (with correctly attached cable)
Protection class	III (PELV)
ATEX-Declaration	Gas (zone 2): II 3G Ex ec ic IIC T4 Gc Dust (zone 22): II 3D Ex ic tc IIIC T135°C Dc
Probe length	Compact version: 250/600 mm Remote version: Probe 250/600 mm; cable: 1 … 10 m (step: 1 m)
Weight	Approx. 500 g max.

¹⁾ Standard conditions: T_N = 20 °C and p_N = 1,013.25 hPa

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

Subject to technical changes.

Order information

	Description	Article-Number
Basic sensor	SCHMIDT^® Flow Sensor SS 23.700 Ex; output signal 4 … 20 mA and 0 … 10 V; impulse output, incl. pressure-tight stainless steel compression fitting; 16 bar overpressure	569 700 -	A	B	C	D	E	F	G	DD
	Options
Type	Standard		1
Mechanical type	Sensor length 250 mm			1
	Sensor length 600 mm			2
	Remote version (selectable sensor length): 250 / 600 mm cable length: ____ m (1 … 10 m; 1-m-steps)			9
	Pressure-tight compression fitting, stainless steel G½				1
	Pressure-tight compression fitting, stainless steel R½ (PT)				2
Measuring ranges and adjustment¹⁾	Measuring range 0 … 10 m/s					1
	Measuring range 0 … 20 m/s					2
	Measuring range 0 … 60 m/s					3
	Measuring range 0 … 90 m/s					4
	Measuring range 0 … 140 m/s					5
	Measuring range 0 … 220 m/s					6
	Special measuring range (10 … 220 m/s) in 1 m/s steps: ___ . ___ m/s					9
	Standard adjustment						1
	Standard adjustment with factory calibration certificate						2
	Standard adjustment with conversion factor for Methan (max. 90 m/s)						3
	Standard adjustment with conversion factor for Biogas (60 % Methan, 40 % CO₂, max. 35 m/s)						4
	Standard adjustment with conversion factor for CO₂ (max. 60 m/s)						5
	Standard adjustment with conversion factor for Natural Gas (88 % CH₄; max. 160 m/s)						7
	Standard adjustment with conversion factor for Argon (max. 100 m/s)						8
	Standard adjustment with conversion factor for special gases and mixtures						9
Impulse output	Standard 100 Hz (= final value of measuring range w_N)							1
	1 impulse / 1 m³ for pipe diameter (round) _____ mm							2
	1 impulse / 0,1 m³ for pipe diameter (round) _____ mm							3
	1 impulse / 0,01 m³ for pipe diameter (round) _____ mm							4
Scope of application	Standard application								1
Scope of application	PWIS-conform (paint-wetting impairment substances), with pressure tight compression fitting stainless steel G1/2 with cutting sealing (only for C = 1)								3
Overpressure	Operating pressure DD: 00 (atmospheric) … 16 bar										00 … 16

¹⁾ Other gases on request.

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

Accessories

Connection technology

Description	Article-Number
Connecting cable, 8-pole, length 5 m, with coupler socket and open cable end	524 921
Connection cable 8-pole, length can be selected (2 … 100 m; 1 m steps), free of halogen, with cable end sleeves ¹⁾	524 942
Power supply unit: output 24 V / 1A DC, supply voltage 115/230 V AC (strip terminal)	535 282

Mounting and fixing technology

Description	Article-Number
Welding sleeve, steel, G½ acc. to EN 10241, 5 pieces per pack	524 916
Welding sleeve, stainless steel 1.4571, G½ acc. to EN 10241, 2 pieces per pack	524 882
Assembly kit for pipe assembly, suitable for MD 10.010 / 10.015, including pipe clamps and collar for adjustment to pipe diameter	531 394
Probe ball value 1" inside thread, connection to flow sensor: ½" inside thread, incl. plug and chain	530 940
Probe ball value 1 ¼" inside thread, connection to flow sensor: ½" inside thread, incl. plug and chain	530 941
Probe ball value 1 ½" inside thread, connection to flow sensor: ½" inside thread, incl. plug and chain	530 942
Probe ball value 2" inside thread, connection to flow sensor: ½" inside thread, incl. plug and chain	530 943
Straight-run probe ball valve ¾" inside thread, with threaded adapter for ½" full-length screw connection	532 355
Welding socket, steel, outside thread ¾", 5 pieces per pack	531 200
Welding socket, stainless steel, outside thread ¾", 2 pieces per pack	531 201

Measured value display

Description	Article-Number
LED display MD 10.010 in wall housing to show volume flow and flow velocity, 85 … 250 V AC and sensor power supply	527 320
LED display MD 10.010, similar to 527 320 but with 24 V DC voltage supply	528 240
LED display MD 10.015, similar to 527 320 but with additional sum function and second measuring input	527 330
LED display MD 10.015, similar to 527 330 but with 24 V DC voltage supply	528 250