Drying method, especially for inside of security camera, uses one way filter with direction selective water vapor permeability to allow space inside casing to breathe

摘要

An airtight casing (10) is provided around the space (2) to be kept dry and at least one opening (17) is provided in the casing. A one-way filter (40) is provided in the opening and has a direction-selective water vapor permeability so that the permeability in the direction from the space towards the ambient atmosphere is greater than the permeability in the opposition direction. Fluctuations in the pressure drop across the filter are made to occur. Independent claims are also included for the following: (A) Camera (1), especially a security camera, comprising an airtight casing containing at least one airtight window (16) for an image sensor (22) and containing at least one opening which houses the above one-way filter; (B) Packaging for transporting or storing moisture-sensitive objects, comprising an airtight casing containing at least one opening which houses above one-way filter; (C) Optical instrument comprising an airtight casing containing at least one opening which houses the above one-way filter and (D) Double glazing unit comprising two or more glass panes sealed within an enclosing film and containing at least one opening which houses the above one-way filter.