PTFE Bushing Protect Graphite Immersion Plate Heaters
Shown here in white PTFE, a bushing is installed in a graphite immersion heat exchanger. The bushing provides a number of features that enhance the lifetime of the plate heater. While bushing could be manufactured from a range of materials, PTFE provides an excellent blend of mechanical characteristics and chemical compatibility or corrosion resistance.
- Graphite can be threaded with small diameter pipe threads for service connection (to steam lines for instance); however the small thread are relatively weak due to the small amount of graphite surrounding the threads. By using a larger diameter thread and a bushing, the strength of the interface is improved substantially.
- The PTFE bushing also has excellent dielectric properties that reduce possible galvanic action at the fitting interface.
- The PTFE bushing also reduce damage to the graphite heater if excess mechanical force is placed on the service piping. The service pipe may damage the bushing without breaking the graphite.
- Threading service fittings directly into graphite can be an intimidating processes, since damaging the graphite plate heater service port is costly and time consuming to repair. Factory installed bushings greatly reduced the risk of installation related damage.
Active Chemical Systems Inc. encourages the use of PTFE bushing on all direct threaded graphite service connections.