Reliable Point Level Detection with an Extended Reach

The Liquiphant FTL81 is designed for liquid level applications where the switching point needs to be reliably detected at a specific position inside a vessel.

Its vibronic measuring principle provides dependable MIN and MAX point level detection, while the extension pipe up to 3 m (9.8 ft) allows the sensor to reach deeper into tanks and vessels.

This makes the FTL81 a particularly practical choice when a standard-length level switch is not enough to reach the required measurement point.

Designed for Safety-Critical Applications

The FTL81 is more than a conventional point level switch. It is designed for FailSafe overfill protection and functional safety applications up to SIL3.

The device features permanent self-monitoring and internal redundancy, while its permanent LIVE signal monitors the functional safety of the instrument. This approach helps maintain high availability of the measurement signal when the level switch forms part of a safety system.

Reliable Even Under Difficult Process Conditions

A major advantage of the Liquiphant measuring principle is that the reliable measurement values are not affected by several common process disturbances.

The FTL81 is specified to remain reliable despite:

• Changing media properties
• Flow and turbulence
• Gas bubbles
• Foam
• Vibrations
• Build-up

This makes it well suited to applications where the process medium or operating conditions can change and a stable switching point remains important.

Ready for High Temperatures and High Pressure

The FTL81 is designed for demanding process conditions, with a process temperature range of -60 to +280 °C (-76 to +540 °F).

Its process pressure range extends from vacuum to 100 bar (1,450 psi), while the minimum medium density is 0.4 g/cm³ (0.4 SGU).

These capabilities give the FTL81 a broad operating range for industrial liquid level applications.

Simple Integration into Safety Systems

The FTL81 uses a 2-wire 4–20 mA interface according to NAMUR NE 06 / NE 43.

It can be integrated through the Nivotester FailSafe FTL825 with two-channel safety outputs, or directly into a safety PLC, depending on the system architecture.

No adjustment is required for startup, which helps keep commissioning straightforward.

Long-Term Reliability with No Moving Parts

The vibronic design contains no mechanically moving parts, eliminating mechanical wear during normal operation.

For safety applications, Endress+Hauser specifies a proof-testing interval of up to 12 years, with slave devices testable at the press of a button.

The FTL81 also monitors the fork for conditions including damage, corrosion, build-up and mechanical blocking, helping identify problems before they affect the intended safety function.

Built for Deep Tanks and Different Process Connections

The FTL81 combines its extended sensor design with a choice of threaded and flanged process connections.

Available thread options include G3/4, G1, R3/4, R1, MNPT3/4 and MNPT1, while flange options range from DN25 to DN100, ASME 1" to 4" and JIS 10K to 20K.

The main wetted materials are 316L and Alloy C, depending on the selected configuration.

A Level Switch Designed to Stay Dependable

The value of the FTL81 is not simply its wide temperature or pressure range. Its real strength is the combination of FailSafe operation, permanent self-monitoring, long extension capability and a measurement principle that remains reliable under difficult process conditions.

For safety-related level detection, especially where the switching point needs to be located deeper in a vessel, the FTL81 offers a well-considered and dependable solution.

Key Features

• FailSafe vibronic point level switch for liquids
• Designed for MIN and MAX safety applications
• Functional safety up to SIL3
• Permanent self-monitoring and internal redundancy
• Reliable measurement despite foam, gas bubbles, turbulence, vibration and build-up
• Process temperature -60 to +280 °C
• Process pressure vacuum to 100 bar
• Minimum medium density 0.4 g/cm³
• 2-wire 4–20 mA interface
• Extension pipe up to 3 m (9.8 ft)
• No mechanically moving parts
• Proof-testing interval up to 12 years
• Fork monitoring for damage, corrosion, build-up and mechanical blocking
• Dual Sealing / Second line of defense
• 316L / Alloy C wetted-part options
• Threaded and flanged process connections
• International explosion protection, SIL, WHG and marine approvals depending on configuration

Typical Applications

The Liquiphant FTL81 is suitable for:

• Tank overfill protection
• MIN/MAX level detection
• Safety-related liquid level monitoring
• Deep tank level switching
• High-temperature liquid applications
• High-pressure process vessels
• Hazardous-area level applications
• Applications requiring SIL3 functional safety
• Applications with foam, gas bubbles or turbulence
• Process vessels where build-up may occur

Frequently Asked Questions

What is the Endress+Hauser Liquiphant FTL81 used for?

The Liquiphant FTL81 is a FailSafe vibronic point level switch for liquids, designed for MIN and MAX safety applications and overfill protection. It supports functional safety applications up to SIL3.

What is the maximum process temperature of the FTL81?

The FTL81 supports a process temperature range of -60 to +280 °C (-76 to +540 °F).

What is the maximum process pressure?

The specified process pressure range is vacuum to 100 bar (1,450 psi).

What is the minimum medium density?

The minimum specified medium density is 0.4 g/cm³ (0.4 SGU).

How long can the FTL81 extension pipe be?

The FTL81 is available with an extension pipe up to 3 m (9.8 ft), making it suitable for applications where the switching point is located deeper inside a vessel.

Does the FTL81 support SIL3?

Yes. The FTL81 is designed for safety systems requiring functional safety up to SIL3, in accordance with the standards specified by Endress+Hauser.

Does the FTL81 use a 4–20 mA output?

Yes. The FTL81 uses a 2-wire 4–20 mA interface, specified according to NAMUR NE 06 / NE 43.

Can the FTL81 be used in hazardous areas?

Yes. Endress+Hauser specifies the FTL81 for use in hazardous areas and offers international explosion protection certificates depending on the selected configuration.

Can the FTL81 handle foam and gas bubbles?

Yes. Endress+Hauser states that reliable measurement values are not affected by gas bubbles, foam, flow, turbulence, vibration or build-up.

What process connections are available?

The FTL81 is available with threaded and flanged process connections. Thread options include G3/4, G1, R3/4, R1, MNPT3/4 and MNPT1, while flange options include DN25–DN100, ASME 1"–4" and JIS 10K–20K.