Endress+Hauser TM111 iTHERM Direct-Contact Thermometer

Endress+Hauser TM111 direct-contact iTHERM ModuLine thermometer

The Endress+Hauser TM111 is the thermometer in the iTHERM ModuLine range that has no thermowell: the sheath of the sensor insert is in direct contact with the process medium. That gives the shortest thermal path and the fastest response of the family. The datasheet describes it as a metric direct-contact RTD or thermocouple thermometer for industrial use, with a measuring range of –200 to +1,100 °C and a pressure range up to 75 bar (1,088 psi).

Seven Star LLC supplies the TM111 in Oman and the GCC as an independent supplier in Muscat. Because the sensor itself touches the fluid, this model is best for clean, non-aggressive, non-abrasive lines where speed and low cost matter more than the ability to replace the sensor with the line under pressure.

TM111 technical specifications

How direct contact changes what you can and cannot do

In a thermowell-based thermometer the insert can be pulled while the line stays closed. In the TM111 the insert is welded to its process connection and is not replaceable and not spring-loaded, except where a compression fitting is used as the connection. That is a real maintenance difference: changing the sensor means isolating and depressurising the line. The datasheet also states that there is no standardised flow-rate calculation for thermometers without a thermowell, and recommends a thermowell version if there is any concern about mechanical load.

On the other side of the balance, the lack of a thermowell removes the thermal mass, so a thin-film QuickSens insert reaches the headline t90 under 1.5 s. Direct contact is therefore well suited to fast control loops, such as outlet temperature on small exchangers and skids.

TM111 versions, compression fittings and process connections

• Thermometer without a fixed connection: bare insert, or with a movable TK40 compression fitting (spherical or cylindrical for weld-in, or with G or NPT thread), spring-loaded as an option
• Fixed threaded connections with lagging: G or M thread, NPT thread, or a cap nut with female G 1/2 or G 3/4 thread for existing wells (diameter 9 or 12 mm)
• Versions without lagging, where the terminal head threads straight onto the process connection
• Extension neck in welded-in-place lengths, or the minimum fixed extension on a fixed connection

The datasheet warns that thin 3 mm sheathed cables used with a compression fitting can kink under vibration, depending on length, head weight and orientation, so use the 6 mm insert or support the head on longer assemblies. Compression fittings are rated for lower pressure than the thread itself, and 316L fittings are single use because they deform when tightened.

TM111 compared with the other iTHERM ModuLine models

Choose the TM111 for speed and economy, and move up to the TM131 or TM151 whenever process safety, hot-swap maintenance or high pressure is required.

Selection and ordering checklist for the TM111

• Is the fluid clean, non-abrasive and compatible with the sheath material?
• Operating temperature and pressure against the 75 bar or 50 bar limits above
• Insert diameter 3 mm or 6 mm; sensor Pt100 or thermocouple; accuracy class
• Process connection: thread type and size, cap nut for an existing well, or compression fitting
• Immersion length U and any lagging or neck length
• Terminal head, transmitter and protocol (4–20 mA, HART, PROFIBUS PA, FOUNDATION Fieldbus, IO-Link, PROFINET with Ethernet-APL)
• Hazardous-area zone and approval, SIL where needed

Installation, commissioning and maintenance of the TM111

Because the tip is wet, check chemical compatibility of the sheath before ordering and do not use the instrument for abrasive slurries. Use a new copper seal on cylindrical threads. If the thermometer is fitted into an existing well through a cap nut, remember that the insert is not spring-loaded and the length has to match the well exactly, otherwise a gap will slow the reading.

Fit a transmitter within its ambient limit of –40 to +85 °C. For service, plan shutdown windows for sensor replacement; record the serial number so that an identical unit can be ordered. A periodic comparison with a reference thermometer is the usual proof that drift is within tolerance.

TM111 applications in Oman and the GCC

The TM111 is suited to utility and skid-mounted duties: chilled water and hot water headers in district cooling, cooling-water loops in power and desalination plants, compressed air and lube oil lines, HVAC plant rooms in large buildings, and packaged process units. In hot, humid Gulf conditions, the head with a transmitter is kept inside its ambient limit by a short neck, a shaded location and stainless fittings. Its low cost makes it popular where many measuring points must be supplied for one project.

Information to send with a TM111 request for quotation

• Tag, service, quantity and P&ID
• Medium, temperature, pressure and flow
• Connection type and size, or compression fitting requirement
• Insert diameter, sensor type, class and immersion length
• Head, transmitter and protocol; hazardous-area details
• Certificates needed and delivery site in Oman or the GCC

Documents and quotation

The manufacturer technical information for the TM111 is attached to this page. Read it together with your project specification, because the thermowell, sensor, head and transmitter options that apply to your tag are fixed by the order configuration, not by the model name alone. Approvals and ratings should always be checked against the exact configuration that is quoted.

Seven Star LLC quotes against your data sheet or loop drawing and confirms lead time, stock position and the documents that ship with the instrument. Send us the details listed above and we will respond with a priced offer for delivery in Oman and the wider GCC.