An IP-rated transit case has a water and air-tight seal between lid or cover and body. That seal must be maintained in the face of relative movement caused by rough handling, pressure differentials between interior and exterior, and temperature extremes. That seal is formed by an O-ring. Continue reading
Protective cases are typically used when something delicate needs to be transported from point A to point B. And, you want to ensure it arrives intact. To many, a protective case is nothing more than a case with an inch or two of foam lining the interior. This is an overly simplistic perspective. Protective case designs are quite diverse. Often, they reflect the unique characteristics of the items they are developed to protect. Continue reading
For shipping and transit cases, traditional refrigeration technology is giving way to thermoelectric cooling. Here’s why: Continue reading
At Sierra Cases, we like to stay on top of the latest innovations in material technology, and one of the most revolutionary materials we’ve seen in a long time is spider silk. Being hailed as “the super material of the future,” spider silk is more than five times stronger than steel, ten times stronger than Kevlar, more elastic than a rubber band and yet can be found in some of our own backyards. Continue reading
When space for rack mount equipment is at a premium, there’s usually one direction to go: up. That’s why it can be tempting to look for the tallest possible rack mount case. Here’s why that might not be a good idea. Continue reading
According to the Bureau of Labor Statistics (BLS), back pain is one of the leading reasons for workplace absence. The data reveals many of these injuries occur while lifting. That’s why it’s important to not lift too much and minimize twisting while lifting. Continue reading
In the desert, relative humidity levels may be as low as 5%. In the tropics, 100% is possible. Anything over 40% is generally considered humid. Humidity causes metal to corrode and mold to form. Lower humidity is a problem too, as drops in temperature cause condensation. If that happens inside a transit case or shipping container, the contents can be damaged or completely ruined. Continue reading
Humidity causes mold and corrosion. Add in temperature changes, condensation can be a problem, too. A desiccant placed in an enclosure adsorbs moisture for a while, but eventually it loses effectiveness and needs replacing. Knowing the level of humidity in a transit case or shipping container, action can be taken before damage occurs. Continue reading
You can’t prevent moisture from entering an enclosure. It’s in the sealed-in air. It’s in the enclosed materials. It even permeates through the walls and seals of the enclosure. And, when a transit case is equipped with a breather for pressure equalization, air will be drawn in from outside, too. Continue reading
When warm air meets a cold glass of beer, condensation forms on the surface. The resulting drips may be annoying, but they won’t ruin your beer. Should condensation occur inside a transit case, it’s another story. Continue reading
Newton’s Laws of Motion can be problematic for electronics. Why? The first Law of Motion tells us a body will continue in motion unless acted upon by an external force. In the second law, acceleration is the rate at which an object changes its velocity. It’s dependent upon mass and force. So, drop a box from the back of a truck and it accelerates earthwards until it hits unyielding ground. The contents want to keep moving. Instead, they experience severe, possibly destructive, deceleration. Continue reading
Boats, trucks, trains and planes can be bad for electronic equipment. The constant vibration is the problem. Vibration damages boards and components, which causes premature failure. It’s why mission-critical equipment should be protected in a high-quality transit case engineered to absorb the shaking. Continue reading
Thankfully, deserts cool off at night. That relieves the stress on equipment baking under the scorching sun. The reverse is not true in extremely cold regions. Places, such as Siberia, can see the mercury dive below -50°C (-58°F) and not substantially rise for days or even weeks. Continue reading
According to MIL-HDBK-310, “GLOBAL CLIMATIC DATA FOR DEVELOPING MILITARY PRODUCTS”, the highest temperature ever recorded is 58°C (136°F). This was measured in North Africa in 1922. However, in 2012, the World Meteorological Organization found flaws in the measurement method. So, the official record holder is now Furnace Creek Ranch in California with a temperature of 57°C (135°F). Continue reading
Molding processes are all very similar: a material, usually a thermoplastic, takes on the shape of a cavity. That cavity is created by a mold tool, and is a 3D mirror image of the finished part. What differs between molding processes is how the material gets into the cavity. It can be placed in it, as in rotational or compression molding, or it can be forced in under pressure, which is injection molding. Continue reading
A defense contractor needed a transportable, air conditioned, rack mount case able to handle various climate conditions around the globe on land or by sea. Because it would be installed on the deck of a ship during operation, the case had to meet several military specifications including MIL-648C. Continue reading
High-density polyethylene (HDPE) makes excellent transit cases, especially when formed by the rotational molding process. HDPE is lightweight, strong, corrosion-proof, and resistant to solvents and acids. It remains stable through a wide temperature range. Rotational molding (roto-molding for short) distributes HDPE powder over the surfaces of a mold. The mold is heated and rotated. This allows liquid HDPE to create hollow shapes with complex geometries.
We’re all familiar with electrical heating, but cooling by electricity? Here’s a primer to get you up to speed.
The Thermoelectric Effect
Most engineers are familiar with the thermocouple. A pair of dissimilar electrical conductors are arranged in parallel and joined at each end. Continue reading
High temperatures shorten the life of electronic components. That’s why cooling is essential. And, as designers continue to increase the power density of modern systems, the problem is getting worse. So, to avoid premature failure when electronics are mounted in a transit case, proper cooling is paramount.
The greatest strength of the well-constructed transit case is also its greatest weakness. An airtight seal keeps moisture and dust at bay but can lead to a significant pressure differential. If the case becomes pressurized—say you close it at night and leave it in the desert sun all day—the sides might bulge, and the seal could give way. Continue reading