Peek polymer selected for insulator in sensor

Edited by the Engineeringtalk editorial team Dec 22, 2000

Victrex Peek polymer has been selected by the Foxboro Company for the insulator component of its award-winning 871FT series of non-invasive sanitary flow-through conductivity sensors

Victrex Peek polymer has been selected by the Foxboro Company, Massachusetts, for the insulator component of its award-winning 871FT series of non-invasive sanitary flow-through conductivity sensors.

In addition to meeting tough mechanical and thermal demands, Peek polyaryletherketone offers full compliance with FDA and 3A standards, making the sensor uniquely suitable for dairy applications.

According to Joe Downey, Marketing Manager at Foxboro, "The 871FT sensors are used to measure the conductivity of liquid solutions in processing industries where temperatures can run as high as 200C (392F) and pressures range between 200-250 psi.

We chose Peek polymer because it retains superior mechanical properties under the kinds of processing conditions found in the food, pharmaceutical, pulp and paper and chemical industries." "The fact that Peek polymer meets all the requirements of the U.S.

Food and Drug Administration (FDA) for use in food contact applications was a necessary requirement for being 3A approved," explains Downey.

"The 3A Standard requires that any sensor coming into contact with a dairy product must have a surface finish of 16 micro inches or smoother.

Because Peek polymer can be machined to a food grade finish, we are able to meet these requirements".

Conductivity sensors are used in processing industries because conductivity is proportional to the amount of impurities in the liquid solution.

"For example," explains Downey, "juice manufacturers will periodically clean their processing lines with a caustic solution.

After the caustic solution has cleaned the lines, water is pumped through and then the conductivity is measured.

As long as there is residual cleaner remaining in the water, there will be a high conductivity value.

As the line gets cleaner, the conductivity level will drop until the point is reached where the manufacturer can begin pumping juice through the line again." "In other situations, sensors may be used to control the concentration of acids, bases and solvents," continues Downey.

"For example, a pickle manufacturer may want to maintain the concentration of salt at a certain level, which could be 10% to 12% by volume.

An analytical device like the sensor is needed therefore to maintain this level".

Chemical resistance is a critical property requirement in sensors as many applications are exposed to strong chemicals such as cleaning and sterilizing products.

Peek polymer is insoluble in all common solvents, and, being semi-crystalline, has excellent resistance to a very wide range of organic and inorganic liquids, even at elevated temperatures.

Victrex plc, which has its sales, technical and production headquarters at Thornton Cleveleys in Lancashire, UK, had a turnover of more than £58m in the last financial year.

The company exports 98 percent of its VICTREX Peek polymer output to OEMs in the automotive, industrial, medical, food and electronics market sectors in Europe, North America and Asia Pacific.