Temperature: Flexible sensor installs in straight and bent thermowells

By Control Engineering Staff July 19, 2007

Here’s something for your maintenance technician: a temperature sensor that can be cut to length and even bent for insertion into existing thermowells. This device eliminates the need for a variety of different lengths and can save time required to replace and repair sagging or damaged thermowells. The Worm flexible sensor, from Moore Industries , helps save maintenance time and reduces inventory.

In new and MRO applications, Worm flexible sensors replace straight probes with a rugged flexible design that installs in minutes. The designs reportedly provide response times faster than any other standard straight sensors, with all popular RTD and thermocouple configurations available.

With straight sensors, the connection head and thermowell assembly components must normally be removed for installation. The Worm bends around and through the top or face of the enclosure, sliding through the enclosure’s entry port, and snaps into place without removal of the enclosure, rigid conduit, connection head, or any assembly components.

The company says a Worm sensor can be installed using a pair of pliers and wire cutters. The installer simply determines the proper length, cuts the Worm spring accordingly, slides the spring over the sensor wires, snaps a cap/clip on the end, and slides the assembly into the thermowell, enclosure or transmitter head. Spacers are supplied to keep the assembly straight.

The Worm is reportedly largely immune from external temperature effects, even in a short thermowell. The temperature assembly keeps the spring-loaded sensor in place, shielding it from external ambient temperatures that can throw readings off. Worm sensors are available with a variety of RTDs and thermocouples, including 100 and 1000 ohm, platinum, copper, nickel RTDs, J- and K-type thermocouples, and others. Worms interface with PC-programmable or HART temperature transmitters, also available from Moore Industries.

—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com , Control Engineering Weekly News