INNOVATIVE DESIGN FROM ENTRATECH SYSTEMS RESISTS CORROSION IN NEW LONG-LIFE COOLANTS
03 November 2002 - Solvay Advanced Polymers Llc

“Typically these sensors are put into a cooling system’s expansion tank,” explains Mike Richardson, president of Entratech Systems, “but because of the high-temperature properties of the AMODEL resin, this new design can be installed directly into the radiator.”

Unique design, unique material
Conventional sensors send a continuous current path through a metal probe tip immersed in the coolant. The hybrid organic-acid technology used in new long-life engine coolants, however, can corrode the probe through the action of electrolysis. Richardson’s design uses a proprietary AC type of signal sent through a stainless steel probe.

The sensor incorporates special circuitry with an on-board microchip to process the signal from the coolant. A connecting wire to an indicator lamp or other warning device alerts the equipment operator to a low-coolant situation. The circuit can be interfaced to engine computers, it performs a power-up self test, and it features a time delay to prevent false alarms caused by sloshing of coolant in normal operation.

The unit’s stainless steel probe is insert molded into a housing that features integral threads for mounting the sensor into the coolant through a threaded hole in a radiator or expansion tank. A composite design was needed to insulate the probe from a metal tank. Richardson specified the AMODEL material because it is able to retain its dimensional stability at the elevated temperatures encountered in a vehicle cooling system, preventing leaks at the sensor’s installation site.

Operating performance and processing ease
AMODEL AS-1933 HS grade of polyphthalamide was developed specifically for improved performance in automotive cooling system environments. This material exceeds industry performance requirements even when tested at temperatures as high as 135°C (275°F). It also resists degradation or dimensional change after prolonged exposure to conventional glycol or long-life HOAT coolants.

This glass-reinforced grade can be readily processed using conventional equipment and methods. Entratech molds its housing on a press that has cartridge heaters in each mold half. Richardson says, “the material runs well, and we have not experienced any instances of incomplete mold fill.” Maximum part density was established through experimentation and programmed into the molding machine computer.

In final assembly, the probe is attached to the circuit board by a threaded stud, and the board is encapsulated in a two-part epoxy potting resin. Power, ground, and signal wires exit the potting for appropriate attachment to a vehicle’s electrical system.

http://www.solvayadvancedpolymers.com

More News:
  • For November 2002
  • From Solvay Advanced Polymers Llc
  • For High-performance polymers