- Published on Monday, 10 September 2012 09:16 - Written by Ed
Holtgraver Sub-arctic climates experience temperatures from 100°
F (38° C) in the summer to –60° F (–51° C) in the winter (Figure
1). While there is nothing spectacular about the high end of the
range, the low end impacts the functionality of pneumatic
actuators. WHAT CAN HAPPEN There is never a good time for an
actuator to fail, but a failure when the temperature is at 60
below or when a blizzard limits capacity for transporting repair
parts could be especially troublesome. Careful selection of
valve actuation is critical. When considering safety integrity,
one assesses what might cause failure in a product. To
illustrate, let’s begin with an off-the-shelf pneumatic actuator
intended for normal service and then consider what may fail if
applied at –60° F (–51° C). Our basic parameters are as follows:
- The actuator housing is steel. - The drive shaft is a
precipitation-hardened stainless steel. - The seals are buna. -
The shaft bushings are Nylon