Dry Storage Cabinets For Optics – Check This Out..
A useful first step to eliminate enclosure moisture is to define the enclosure environment utilizing a temperature/humidity data logger. These affordable, battery-powered devices (~$200) record Electronic Dry Cabinets. Additionally they indicate the dew-point conditions inside the enclosure (Fig. 6). Maintaining enclosure temperatures above dew-point temperatures is a requirement for condensation prevention.
Pursuing this option can be accomplished in a variety of ways, ranging from desiccant to thermoelectric dehumidifiers-the challenge is to select an alternative which is inexpensive to both implement and keep. Water-absorption ability of desiccant is dependent on many different factors (e.g., desiccant type, humidity, temperature). As an example, silica gel can absorb up to 40% of its weight in water. A 4’ x 6’ x 2’ electrical enclosure in a hot/humid environment would saturate 125 g of desiccant within two air exchanges. Therefore, the resulting frequency of required desiccant change-outs (which affects maintenance costs) is basically driven by how well the enclosures are sealed. Unfortunately, when it comes to desiccant regimes, each act of opening an enclosure to examine the desiccant may serve as an air exchange.
Dehumidifiers are relatively inexpensive, although finding convenient available power inside an enclosure may be problematic. The positive feature is that dehumidifiers remove the manual intervention connected with a desiccant regime. The negative feature of dehumidifiers is because they introduce yet another piece of equipment that can ultimately fail.
Another strategy is to lower the opportunity of condensation through internal heaters (or light bulbs) to help keep the interior enclosure temperature well above dew-point temperatures. The down-side is the fact that higher temperatures may be detrimental to some heat-sensitive electronic components, and also the higher temperature actually allows the air to hold more moisture. Venting and fans can help avoid condensation in certain situations-although the Dry Storage Cabinets For Optics still exists. One interesting product the designers of GORE-TEX® have produced involves screw-in vents which allow enclosures to breathe, while providing a barrier to moisture and contaminants. The theory behind this kind of venting is that it decreases the stress on door seals when you can find pressure differentials between the enclosure as well as the environment. By equalizing pressure, the chance of moist air at higher pressure defeating your home seals is lessened.
Moisture-hardening of electronics includes a variety of techniques. In terms of connectors, using waterproof connectors or hardening existing connectors and splices with heat-shrink tubing can be of use to minimize water intrusion and corrosion. Avoiding horizontal orientation of components like printed circuit boards in the enclosure can minimize surfaces where condensation may collect for longer amounts of time. Conformal coatings for lower-voltage printed circuit boards and the use of potting (see Fig. 7) of higher-voltage components greatly boost the moisture resistance of components. Potting costs vary according to the scale of order, material selection jmmhra part geometry, but representative costs for very small orders (less than 10) typically fall within the range of $18 to $45 per part. Yet another advantage of potting is the added defense against shock and vibration.
Moisture protection of electronics is most beneficial approached by pursuing practices that maximize Moisture Control Cabinets during equipment installation, coupled with being willing to mitigate failure through any one moisture-protection measure during operations. This tactic, along with tracking equipment-maintenance performance to know how well moisture-protection measures work, can lead to long-term minimization of electronics moisture-induced problems. MT.