Standard and Hazardous-Duty Features of DMC Air Conditioners
Hazardous (Flammable and Explosive) Locations
DMC offers the most rugged hazardous-duty air conditioners. It designs and builds its units from scratch for both harsh duty and hazardous duty. Therefore, all its "explosion-proof" air conditioners meet the same high standards for extreme duty as its standard products.
If your equipment needs to be not only rugged but also safe ("explosion proof") for use in the presence of hazardous gases, dusts or flyings, click here
Options
DMC standardizes its products to speed delivery and to enable us to offer products that can serve most tough applications without the delays and additional costs of making the additional features, options.
However, many applications need at least minor changes to the basic products — most commonly to the electrical configurations, to add heat, and to make them safe for hazardous areas. Therefore, DMC offers a number of options. Click here to go to Options page.
We acknowledge that many of our clients do not normally concern themselves with the types of problems that DMC builds products to solve. Consequently, they need help in identifying the problems, as well as in understanding the solutions. Therefore, we have set up this site with three key aspects:
- I. Training and Informational Resources — Materials to help prospective users educate themselves on the areas related to harsh environments. This is designed specifically to introduce information to enable people with only a passing interest in the topics to solve their immediate problems.
- II. Information by Industry and Type of End User — Information about the problems of potential users according to specific industry, and specifically how DMC can help with your particular needs. This section helps identify potential solutions to your problems, and then shows how DMC might provide those solutions.
- III. Information About Our Products — Materials about the types of products that DMC offers,and their features, construction, and applications.
If these standard features do not meet all of your requirements, DMC also offers a variety of additional options.
DMC designs and builds all its air conditioners specifically for harsh conditions, whether intended for hazardous-duty or for non-explosive environments. As a result, all units have the following features to make them more durable and reliable than light-industrial and commercial-grade units in corrosive, dusty, humid, hot, cold, hazardous and other difficult environments:
- To increase durability, we make the cabinets of heavy-gauge 316L stainless steel, not the 22 gauge or lighter painted or galvanized steel found in most commercial-grade units. We use type 316 stainless steel instead of type 304 stainless because it resists corrosion much better in a wider variety of harsh environments.
- To help resist acidic and caustic corrosion as well as that from salt and humidity, DMC protects all condensers and evaporators with a low-porosity (close to zero) epoxy coating (e-coat) electrostatically applied by immersion and then baked.
- To make air conditioners less sensitive to electrical problems and easier to repair, DMC uses only mechanical controls, not electronic. We protect the controls of ordinary-location units inside a sealed NEMA 4X/IP56 box and those of hazardous-location units in a NEMA 7 box.
- To enable dirt and sand particles to pass between the fins without clogging them, both the evaporator and condensers have a maximum of 10 heavy-weight fins per inch instead of the more common 14 to 20 light-weight fins. DMC also use extra strong fan motors to enable them to move dusty air through the units.
- DMC air conditioners cool well at low ambient temperatures, because our patented design enables DMC units to maintain their full rated cooling capacities up to 131°F (55°C) and down to 32°F (0°C) without modification (and down to -40°F/C as an option). Hence, these air conditioners will cool when the ambient temperatures are too low for ordinary air conditioners, but when it is still warm enough for a sealed building in the sun to heat up uncomfortably.
- By designing the units for high ambient conditions and rating them at 131°F (55°C), we assure that they will have extra cooling capacity at lower ambient temperatures. For instance, at 95°F/35°C, the standard temperature generally used for rating commercial-grade air conditioners, DMC units have an actual capacity more than 20% greater than their rated capacities. We also assure that they maintain their full rated cooling capacities at high altitudes.
- To lengthen the life of the fan and blower motors, we use specially-made totally-enclosed motors with 300-series stainless-steel shafts mounted on ball bearings and designed with Class F insulation for continuous duty at 70°C.
- DMC uses only tough backwardly-inclined blower wheels for both the evaporators and the condensers. The wheels are made of an especially strong polyamide 6 plastic reinforced with 30% glass fiber — to make them stronger, quieter, more energy-efficient, better able to handle heavy sand and dust loads in the air, and more corrosion-resistant than other types of wheel, particularly propeller types made of aluminum or with slinger wheels.
- To make them more durable and maintenance free, the DMC air conditioners use only resilient low-maintenance hermetically-sealed scroll compressors instead of reciprocating, rotary or open-drive compressors.
- DMC wires the units for many different electrical configurations. We can also adjust the designs to compensate for loss of capacity when operating the units at 50 Hz instead of 60 Hz.
- To ease maintenance and make access simple, DMC mounts components on a reinforced 16-gauge 316L slide-in tray. We also include at least four refrigerant-access valves, a head-pressure control valve, a shut-off valve on the receiver, an expansion valve, a suction-line filter/dryer, a moisture indicator, a sight glass and a receiver. A head-pressure control helps eliminate the possibility of freeze up of the evaporator. We also protect the units against high and low refrigerant pressures and against overheating of the compressor and other motors.
- To avoid corroding the condenser by mixing condensate water with the corrosive gases and particles in the air, DMC makes the units with dry condensers by using fans without slinger rings (which throw the condensation back onto the condensers in commercial-grade units).
- Air filtration is provided by permanent polypropylene electrostatic type filter elements secured with Velcro strips to make them easy to remove and remount after cleaning with compressed air or water.
- The units will meet the NEMA 4X and IP56 standards so that they will have long lives in corrosive and/or wet environments.
- In those units with heat, DMC provides integral electrical-resistance heat with corrosion-resistant incoloy tubular elements (not light-weight wires) in capacities of 5KW or 10KW.
- DMC air conditioners are the "greenest" under harsh conditions; because DMC designs its units specifically for operation and durability under extreme conditions, they retain their energy efficiency in tough environments, not just in clean testing laboratories when new.
- DMC uses environmentally-friendly refrigerants.
- DMC makes all its equipment in the United States of America.
