Many enclosures for industrial controls, e.g., pneumatic positioners, require venting. Typically, such venting is accomplished by cutting a hole in one of the exterior surfaces of the enclosure and covering the hole with a fine mesh screen. This approach does permit venting, however, it does not prevent windblown dust and rain, splashing water, hose-directed water, etc., from entering the enclosure and possibly damaging the contents thereof. Thus, this venting technique and other variations thereof are unsatisfactory since they may result in undesirable damage to the controls contained within the enclosure and costly downtime for the machine or device being regulated by the controls.
Because of the foregoing, it has become desirable to develop a device which permits the venting of an enclosure and prevents the entry of contaminants into the enclosure.