Thermowells for thermometers to DIN 43772

The thermowell separates the measuring insert from the process. It withstands pressure, flow and attack by the medium, and it makes sure the sensor can be changed during operation without opening the plant. If it fails, it is not only the measuring point that is down — it becomes a leak.

We manufacture thermowells to DIN 43772 and ASME PTC 19.3 TW in Hanau, individually and in series: as a tube or from solid material, with a thread, flange or for welding in, in stainless steel, special materials or with a tantalum coating. Rebuilds to sample or drawing are the normal case, not the exception.

All designs fit our measuring inserts and connection heads — you can order a complete thermometer or just the spare tube.

Which design suits your installation?

Form 2 and form 3 differ only at the tip: the tapered tube reacts faster and withstands higher flow velocities, the straight tube is more stable and cheaper. Solid material (form 4, 4F, 45) is chosen for high pressure, high flow velocity or when a thermowell calculation is required.

Thermowells to DIN 43772

The classic designs for chemicals, energy and plant engineering — as a tube or from solid material, for plugging in, screwing in, welding in or flange mounting.

Corrosion protection with tantalum

Two-part flanged thermowells in which the tube is centred and clamped by the flange. The tantalum coating is included in the scope of supply and withstands even hot hydrochloric and sulphuric acid.

Furnace construction — metal and ceramic

For heat treatment, melting and firing processes. Up to +1,250 °C the metal tube to DIN EN 50446, above that the gas-tight ceramic tube.

Materials

Stainless steel
1.4571 (A182 F316Ti) is the standard and covers most applications. 1.4404 (F316L) is chosen where a low carbon limit is required, 1.4539 (F904L) for media containing chlorides. 1.0460 (A105) is used for solid-material thermowells in the steam circuit.

Coatings and linings
Tantalum for hot acids, ECTFE (Halar) and PFA for aggressive aqueous media, TP-50 as a non-stick layer, Stellite 1 and 6 against erosion. The tantalum coating on the RMR-2FT and RMR-3FT is included in the scope of supply.

Furnace materials
For temperatures above +800 °C, 1.4876, 1.4841, 1.4749 and 1.4762; Kanthal APM reaches +1,250 °C. Above that only ceramic remains.

Tests and calculation

With every thermowell we supply, on request, a 3.1 material test certificate to EN 10204 and dye-penetrant, pressure and X-ray testing. The strength calculation to DIN 43772 or ASME PTC 19.3 TW checks whether the tube withstands the flow and whether its natural frequency is far enough from the vortex shedding frequency — at high flow velocities that is the real reason for the design.

For the calculation we need the medium, density, operating pressure, temperature, flow velocity and the pipe inside diameter at the measuring point. Please add these details in the configurator under "Tests".

Thermowell on its own or a complete thermometer?

The thermowells on this page are supplied individually — as a spare tube or for installation in an existing measuring point. If you want to order the measuring insert, connection head and transmitter at the same time, the complete thermometers are in the two product branches:

• Resistance thermometers with metal thermowell — Pt100 / Pt1000, bis +600 °C
• Thermocouples with metal thermowell — Typ K, N, J, bis +1.100 °C
• High-temperature thermocouples — TSM und TSK, bis +1.600 °C

Please contact us

We are glad to help with questions about products, versions and delivery times.

Dennis Kühne
Phone: +49 6181 504 93 18
Mobile: +49 160 91437153
E-mail: info@ghi-gmbh.de