Plant loading docks and high-speed doors combine to offer opportunities for big energy savings.
March 20, 2017
by Perry Knuston
Many facility managers miss out on opportunities to maximize energy efficiency – and the cost savings associated with it – throughout their material handling operations.
There is equipment available that delivers energy efficiency gains when moving raw product from cell to cell within a plant or shipping it out on trailers at the loading dock.
Let’s take a more in-depth look at equipment that maximizes energy use from inside the plant to the dock doors in shipping/receiving.
Whether it’s putting raw materials into a cell to be welded or putting thawing food into a freezer, moving materials within a plant results in a massive loss of energy. For many years, plants focused on using doors with high R-values, which minimize heat transfer through an object. These doors are typically heavy and slow moving. In high-cycle processes that demand dozens of openings and closings throughout the day, they’re often left open, allowing air from high- and low-temperature operations to infiltrate other areas in the plant.
Upgrading to high-speed doors provides an R-value high enough to minimize conduction of heat while delivering quick operational speeds. The most advanced high-speed, roll-up doors operate up to 2.5 metres per second. And minimizing air nfiltration conserves energy in a big way.
Hard-core doors are susceptible to forklift damage and the air penetration continues until they’re repaired. High-speed doors take a hit and automatically re-align on their tracks.
Industry-specific high-speed doors made from a smooth polypropylene fabric that handles acids and bases help facilities comply with the strictest of regulations. For example, the most advanced, CFIA-compliant roll-up doors will incorporate a one-piece radial header and non-corrosive side frames that are removable for regular cleaning. They also align with current good manufacturing practices.
Loading docks present one of the best opportunities for improved energy efficiency.
Drive-throughs provide energy benefits for many types of facilities. Since they allow docked trailers to open their doors inside the facility, they prevent the infiltration of outside contaminants, preserve cold chain integrity and reduce opportunities for conditioned air to escape through open loading dock doors.
After the trailer is secured to the loading dock, a vertical storage leveller bridges the difference in height and gaps between the dock floor and the trailer bed. They allow the loading dock door to close directly on the pit floor. This reduces energy loss by minimizing outside air infiltration and helps reduce contaminants from entering the building.
Security is enhanced by minimizing points of entry at the loading dock; and cleaning or washing down the pit floor is easier when the leveller is in the upright and stored position.
Vertical levellers provide the smoothest path between the facility floor and the trailer, which reduces “dock shock,” or whole-body vibration. That’s good for forklift operators and minimizes damage to products and equipment. The most advanced levellers reduce dock shock by incorporating specialized rear and front hinges that minimize the bumps and gaps. And a finely tuned lip chamfer at the front of the leveller reduces the speed bump effect normally felt by forklift drivers as they enter and exit the trailer.
The second piece of a good drive-through operation is a loading dock seal and shelter system. It creates an environmental barrier between the back end of the semi-trailer and the inside of the loading dock, dock seals and shelters to keep wind, rain, dust, bugs and other contaminants outside the building.
Some of the newest dock shelters, specifically designed for drive-through applications, complement vertical storing dock levellers. This allows the trailer doors to open inside the building, while still maintaining a tight, consistent seal around the trailer. Special design features ensure tight sealing against sides, across the full width of the top and at the corners without interfering with the opening and closing of trailer doors.
To complete a four-sided seal, an under-leveller seal closes off the space beneath the vertical leveller that is lowered into the back of the trailer.
Although safety is the most important consideration for any material handling operation, energy efficiency is also key. Plant managers now have options inside the facility and at the loading docks.
Perry Knutson is director of engineering for Rite-Hite Doors, a manufacturer of loading dock equipment, industrial doors, safety barriers and HVLS industrial fans based in Milwaukee, Wis.