Series-FLT93

Supported Applications

The FLT93 Series FlexSwitch is a heavy-duty thermal dispersion flow, level, and temperature switch and monitor for industrial processes. Because thermal dispersion sensing has no moving parts, the switch responds to changes in fluid flow, liquid level, or temperature to trigger an alarm or control signal with minimal maintenance.

The insertion-style design uses a configurable, modular construction with customizable sensor elements, control circuits, and interconnecting cables, allowing tailored setups for both hazardous and non-hazardous environments. This makes the series a good fit for flow and level detection and temperature monitoring of gases and liquids, including wet/dry interface detection, across process, utility, and safety-interlock duties.

Operating Conditions & Performance

The FLT93 handles a wide process temperature window, offered as -40 to 177°C and, for higher-temperature service, -73 to 260°C. Pressure ratings are grouped into a low-pressure class to 3.5 bar and a medium-pressure class to 35 bar.

• Power: 115 Vac, 230 Vac, 24 Vdc, or 24 Vac.
• Alarm output: SPDT or DPDT relay contacts.
• Cable entry: one 1" NPT, two 1/2" NPT, or two M20 entries.
• Wetted materials: 316L stainless steel (standard or electropolished), Hastelloy C, and Monel 400.

Process connections include 1/4" Male NPT, 3/4" Male NPT, 1" Male NPT, 1" Male BSPT, flanged, and a retractable packing gland with graphite packing material. Insertion depth is selectable across 30 mm, 51 mm, 102 mm, 152 mm, 229 mm, 305 mm, and 457 mm. Local enclosures are offered in stainless steel and aluminum, both with agency approvals for hazardous locations covering Groups B, C, D, E, F, and G and Exd IIC.

Configuration Options

The FLT93 family is highly configurable through a structured model number, so units differ by base model, application, enclosure, output, and options.

• Model designator: B (basic model with standard features), C (sanitary model with 3A certification), F (flow model with high sensitivity), L (in-line NPT model for pipe mounting), and S (standard model with enhanced durability).
• Application type: FL for flow, LV for level, and TM for temperature.
• Enclosure type: standard polycarbonate, 316L stainless steel, or explosion-proof.
• Output configuration: SPDT relay, 4-20 mA current loop, or 0-10 VDC voltage output.
• Agency approval: options include Factory Mutual (FM), FM (T4 rated), ATEX with CE marking, and FMc.

Additional order options add an alarm relay with LED indicator, a built-in heater for low-temperature applications, an RS485 communication interface, and a remote mounting kit.

Key Product Differences

Configured part numbers are built from the model designator followed by the option string. The five catalogued configurations in this series are:

• FLT93F-1B1A203C4A00000
• FLT93F-1B2A203C4A00H21
• FLT93S-1B1A201C4B00000
• FLT93S-1B1A202C4B00000
• FLT93S-1B1A203C4B00000

The FLT93F builds are high-sensitivity flow versions and the FLT93S builds are standard, enhanced-durability versions; both draw on the same FlexSwitch sensing platform and modular option set described above.