If the lifting requirements exceed the capabilities of a hydraulic crane, or jobsite conditions limit access to the work area, an articulating crane can be an effective alternative.
These types of cranes are suited for those applications that need more lift and reach, IMT officials say. These cranes can operate lower to the ground so they are helpful in avoiding overhead obstructions. Because they are also typically lighter than hydraulic telescopic cranes of comparable capacity, they can carry more payload.
Articulating cranes, which come with stabilizers built into the crane base, also enable more precise placement of material.
With truck-mounted air compressors, the key is to correctly size a compressor to the application. If a compressor is undersized, it will take more time to finish a task. If oversized, there may be efficiency issues.
A compressor is usually sized according to the amount of air it can compress to 100 lbs per square inch (psi) in one minute, which is denoted in cubic feet per minute (cfm), officials at Kaeser Compressors, a leading worldwide manufacturer of energy-efficient compressed air equipment (www.kaeser.com), say.
Altitude can affect cfm ratings, note officials at Chicago Pneumatic, a quality leader in performance air tools since 1901 (www.cp.com). The higher the altitude, the thinner the air and the less cfm a compressor can generate. Air compressor manufacturers have charts available that will outline cfm ratings at higher altitudes.
The first step in determining the size of air compressor needed is to determine the types of tools that will be running. Then, the cfm requirements to run the tools need to be established. This information is typically labeled on the tool, or can be found in the owner’s manual.
Next, determine if there will be the need to run more than one tool simultaneously, and how often air will be needed. Some compressors have several outlets to power multiple tools.
Undersizing an air compressor is usually not the problem, note officials at Vanair, the world’s largest manufacturer of powerful, lightweight and compact vehicle-mounted air compressors, generators, welders and battery boosters (www.vanair.com). A common mistake is the tendency to oversize the unit.
Most pneumatic tools are rated at 90 to 110 psi, they point out. Delivering higher pressures to the tools than required can cause damage and will shorten tool life.
Oversizing can also impact the compressor’s longevity, add officials at Doosan Infracore Portable Power, whose product line includes generators, air compressors and light towers (www.doosanportablepower.com/americas). A compressor that is too large won’t work hard enough. If it is never really loaded, it won’t build up enough heat to evaporate the moisture, and that can shorten the life cycle.
The inability to achieve the desired operating cycle can also lead to trouble with the air/oil separation system that removes the compressor oil (used to lubricate the system) from the compressed air, they add.
Air compressors come in rotary screw and reciprocating piston models and each has certain benefits.
Rotary screw compressors are compact, lighter weight than reciprocating piston compressors and are designed to run for extended periods of time, making them more efficient, say IMT officials. Plus, they have on-demand air. As soon as the compressor comes on, it is producing air.
Reciprocating compressors are designed for short, intermittent job needs, they continue. These models are more forgiving, are not as susceptible to moisture or particulate contamination and are “significantly” less expensive than rotary screw units.