Global Processing

New temperature sensor for autoclave steam sterilizers resists moisture intrusion

June 30, 2008
New moisture-resistant RTD is designed for the harsh environments of autoclave steam sterilizers. The new RTD, Model 3312B, uses a proprietary cable material that withstands moisture intrusion during pressure and vacuum cycling, and meets USP Class VI requirements for use in sanitary environments. The new cable material also withstands the physical abuse that often occurs during loading and unloading of large sterilizers. The material has low memory and, thus, resists kinking. Model 3312B comes in a variety of both sheath and lead-wire jacket diameters. It is also available in a sharp-pointed version for easy insertion into rubber capped vials, small bottles in tray washers and sterile bags. It does not sacrifice time response, assuring quick, accurate temperature measurement without delay or inaccurate readings. The 3312B was developed after extensive research at Weed Instrument demonstrated that with Teflon or Silicon jacketed wires, the two material types used in most other autoclave sensor designs, moisture intrusion frequently occurs. During the pressure and full vacuum cycling in the sterilizer chamber, moisture is drawn through the jacketed material and onto the bare copper wires leading to the sensor. Repeated testing over an 8 month period proved that sensor failure is a function of the cable material and not improper sealing of the cable to the sensor. The 3312B, which utilizes the proprietary cable jacket material, eliminates the moisture intrusion problems.