New sensors & controls for temperature, pressure.

New and updated sensors and controls for temperature and pressure were recently announced by Gefran, Inc. (formerly Gefran ISI), Winchester, Mass. The latest addition to the firm's Geflex line of modular temperature controls is the GFX4, the first four-loop model in the series. Introduced in 2003, the Geflex family was the first to combine a PID controller, power solid-state relay (SSR), current transformer, and digital communications in one device (above).

Also new are redesigned M and W series (mercury- and oil-filled, respectively) melt-pressure transmitters for extrusion. They include a feature said to be brand-new to melt-pressure sensors: zero-output correction with a magnetic pen. The new Autozero function eliminates signal variations in the absence of pressure, but requires no screwdriver adjustment of of an internal trim "pot." Instead, the operator uses a magnetic "pen" attached to the outside of the transmitter (right).

Also new is the "GTP" coating on the sensing tip, which lowers the coefficient of friction and is highly resistant to abrasion, corrosion, and high temperatures. It is said to give better protection during extrusion than any other coating on the market. In addition, the electronics housing is 20% smaller than before, and the transmitters' accuracy and stability are enhanced by a new auto-compensation feature that adjusts pressure readings for changes in process melt temperature.

A third new development is K-Series sodium/potassium-filled melt-pressure transmitters for temperatures up to 1000 F (538 C). They are aimed at medical tubing and other processes using high-heat engineering resins. The K-Series is available with the same magnetic-pen Autozero function as the M/W series. Tel: [phone] * www.gefran.com

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