Inline process refractometer


PDF data sheet
  • Ex-protection version of the iPR-B3
  • Suitable for all applications in explosion-proof areas
  • Certified according to European Classification ATEX ib II A T4
  • Permanent inline real-time measurement of the concentration of dissolved solids

Automatic process refractometer iPR - EX

Fully automatic process refractometer for direct measurement of dissolved solids, process monitoring and control. Principle of the critical-angle refractometer with sapphire prism and high-resolution photodiode array; no influence of color and opacity of the medium on the measuring result. Measuring head made of stainless steel, chemical resistant, food safe, hygienic, for process temperatures up to 120 °C (with connected water cooling) and pressures up to 1 MPa.

The explosion protection version of the process refractometer consists of an intrinsically safe, single-certified sensor, which is installed in the hazardous area. The measuring signals are routed to the non-explosive area via a special cable (maximum length 500 m) and connected to 4 zener barriers. The connection to the central control system is realized with a RTU Modbus or serial RS 485 interface.

Alternatively, Schmidt + Haensch offers a control unit, which is also installed outside the hazardous area. The 7 “touch screen is individually configurable. The measured data can be output via Ethernet as a 24 V or 4-20 mA signal or control a relay.

For data transmission to other systems, serial RS 232, 485 interfaces, a CAN bus or UPC server are available.

Up to two measuring heads can be connected at the same time.


Main specifications

StandardsATEX Ex II 1G Ex ia IIC T4
IEC in preparation
Measuring range1,32000 – 1,52000 nD
Resolution0,00001 nD
Precision±0,00014 nD


Ambient temperature-20 °C to +65 °C
Process Temperature-20°C to +120 °C*
Temperature resolution/precision0.01°C / ±0.2°C (0° to 70°C)
Process pressure0 to 1 MPa (145 psi, 10 bar)

Additional informationen

Wetted partsSapphire (prism), stainless steel, FKM
Protection classIP 67
Light source / wavelengthLED, 589 nm
Interface, switchesModBus, RS485 and 24V with external Zener barriers
Dimensions330mm x 149mm (length x diameter)

Control unit

Operation1 and 2 measuring headsets are available, connectable with built-in Zener barriers
Display7" Touchscreen, 800x480 pixel
DIN rail parts (expandable)Switch inputs (24 V) and outputs (24 V / relay / 4-20mA) / Communication (RS232 / RS485), CAN, UPC Server
HighlightsConfiguration of measuring head and outputs / Adjust switching thresholds and analog outputs /
Concentration and other scales user programmable
Power85V ... 265V 50/60Hz

* with cooling by cooler circuit only, electronic max. +65°C

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