KROHNE OPTIFLEX 7200 Guided Radar Level Transmitter

Overview of the KROHNE OPTIFLEX 7200

The KROHNE OPTIFLEX 7200 is a two-wire guided radar level transmitter based on Time Domain Reflectometry (TDR) for liquids in storage and process applications. KROHNE describes it as the premium device of the OPTIFLEX family for level and interface measurement in the chemical, oil and gas industries. It covers tank heights up to 60 m, process pressures up to 100 barg and process connection temperatures up to +250 °C, and its modular design allows the converter to be mounted compactly on the probe or remotely from it.

Seven Star LLC supplies the KROHNE OPTIFLEX 7200 to refineries, gas plants, tank farms and chemical sites in the Sultanate of Oman and the wider GCC. As a trusted supplier with engineering support in Muscat, we check probe type, nozzle geometry, process seal and hazardous-area approval against the duty before an order is placed, so the transmitter arrives ready for commissioning.

Measuring Principle

The converter of the KROHNE OPTIFLEX 7200 sends low-intensity electromagnetic pulses of approximately one nanosecond width along a rigid or flexible probe. The pulses travel at the speed of light; when they reach the product surface, part of the energy is reflected back with an intensity that depends on the dielectric constant of the liquid. The device measures the time between emission and reception, and half of that time corresponds to the distance from the flange facing to the surface. Distance is then converted into level, volume or mass, and up to 30 strapping-table points can be stored for volume calculation.

When two liquids are present, the remaining part of the pulse continues through the upper layer and is reflected again at the interface, so the same probe reports level and interface simultaneously as long as the upper liquid has the lower dielectric constant; a reversed interface probe handles cases such as water over carbon disulphide. For products with a very low dielectric constant (below about 1.6), Tank Bottom Following mode calculates the level from the shift of the probe-end reflection. KROHNE states that dust, foam, vapour, agitated or boiling surfaces and changes of pressure, temperature and density do not affect performance.

Engineering Design of the KROHNE OPTIFLEX 7200

Four constructions are available: compact (C) with the converter on the probe; remote (F) with the converter up to 100 m away on a signal cable; sensor extension (S) using a coaxial cable of up to 15 m; and double sensor extension (D) combining both. The housing is polyester-coated aluminium or 316L stainless steel, rated IP66/IP68 and NEMA 4X/6, and a quick-coupling system lets the converter be rotated or removed while the probe stays under process conditions. An optional 128 × 64 pixel LCD with a four-button keypad can be ordered with the unit or added later.

Probe choice is the heart of the KROHNE OPTIFLEX 7200 design. The range includes single rods of 8 mm and 10 mm, a fully TFM-T62 PTFE-coated rod for corrosive media, single and double 4 mm cables for distances up to 60 m, a double rod, a reversed-interface probe and coaxial probes of 22 mm and 42 mm for low-dielectric liquids and narrow nozzles. A PTFE process seal covers −1 to 40 barg, while the ceramic seal system extends the rating to 100 barg and, with a Kalrez 7075 gasket, to +250 °C.

Key Features

The main capabilities of the KROHNE OPTIFLEX 7200 listed in the technical datasheet are:

• Level accuracy of ±2 mm up to 10 m and ±0.02 % of measured distance beyond 10 m, with ±1 mm repeatability.
• Interface measurement with an upper layer as thin as 50 mm and an interface accuracy of ±5 mm up to 10 m.
• Two-wire 4–20 mA output with HART 7, plus an optional second current output or a relay switch output.
• SIL 2/3 certification to EN 61508 for the compact and sensor extension versions, with SFF values up to 95 %.
• Remote converter up to 100 m from the probe and horizontal or vertical housing orientations for difficult mounting positions.
• Ceramic process seal option for pressures up to 100 barg and temperatures up to +250 °C.
• Diagnostics according to NAMUR NE 107, a real-time clock for event logging and a quick setup assistant for commissioning.
• Optional NACE MR0175/ISO 15156 and MR0103 construction for sour-service oil and gas applications.

Industrial Applications

For the KROHNE OPTIFLEX 7200, KROHNE lists typical duties such as hydrocarbon level in refineries, liquefied gas storage, solvents, alcohols, acids and bases, foaming reactors and installation on magnetic level indicators or bypass chambers. In Oman these translate directly to crude and condensate storage at oil and gas fields, separator and knock-out drum interface measurement, LPG spheres installed with a stilling well, and chemical dosing tanks at refineries and petrochemical complexes in Sohar and Duqm. The reversed-interface probe and the 50 mm minimum layer make the instrument a practical choice for oil-water separation in produced-water treatment.

Power and desalination plants in the GCC also use the KROHNE OPTIFLEX 7200 and similar guided radar on condensate pots, deaerators and chemical injection skids, where agitation and vapour would disturb other technologies. For each of these projects, Seven Star LLC supplies the KROHNE OPTIFLEX 7200 from Muscat with the correct probe length, flange rating and Ex approval, and can offer complementary instruments such as the KROHNE OPTIWAVE 7500 radar level transmitter, the VEGA VEGAFLEX 86 guided wave radar sensor or the VEGAFLEX 81 TDR level transmitter where a project standard calls for them.

Technical Specifications of the KROHNE OPTIFLEX 7200

The table summarises data for the KROHNE OPTIFLEX 7200 from the KROHNE technical datasheet TD OPTIFLEX 7200 R03 (02/2024). Final values depend on the probe and process seal selected.

How to Order

To receive a formal quotation for the KROHNE OPTIFLEX 7200, send Seven Star LLC your RFQ with the medium and its dielectric constant, tank height, nozzle size, process pressure and temperature, required probe type, output option and hazardous-area approval. Our instrumentation division in Muscat will confirm the order code and the current lead time. The technical datasheet can be downloaded from this page, and our engineers support customers in Oman and the GCC from selection through installation.