***Under Pressure

Nov. 1, 2001
Every rental center owner, and for that matter every contractor, is looking for ways to maximize equipment productivity and reduce machinery operating

Every rental center owner, and for that matter every contractor, is looking for ways to maximize equipment productivity and reduce machinery operating costs. Many contractors in the drilling and construction industry have requested more pressure, but don't want all the cost associated with a high-pressure machine. New models meet that growing demand and offer more versatility and application possibilities, increasing unit usage while at the same time decreasing operating expenses.

High pressure was once only needed in select applications. Today, many contractors are requesting more pressure because of new applications or technologies that demand that pressure. Not that long ago, to get 200 psi one had to rent a compressor with minimum of 700 cfm. With the introduction of the 400 cfm compressor, the volume decreased considerably, thus decreasing the cost of a machine, although the 400 cfm unit is still more compressor than is often needed. As demand increases in lower volume, higher-pressure applications, the opportunity for the rental house to capitalize on this growth also increases. Following are some examples of those applications.

  • Water well maintenance and rehabilitation techniques are aimed at clearing sediment from the bottom of new wells. In the process, wells must be pumped for a period of time to clear all the small particles. Two hundred psi provides the necessary pressure required for cleaning and pushing material through the filter, and in deeper wells, the pressure to overcome the water head.
  • Directional drilling requires the use of pneumatic hammers when layers of rock are encountered. To drill 3- to 5-inch holes, the preferred operating pressure is above 150 psi. If the pressure is too low, the overall performance is diminished. If the pressure is too high, the hammer can get stuck. Typically, 200 psi provides a good balance between drilling rates and hole accuracy.
  • Ice blasting is becoming very popular in some areas. Because the blasting material is dry ice, no debris is left other than the paint or corrosive substance that is being removed. The dry ice particles from the machine hitting against the surface remove the old paint or coating. A pressure of about 200 psi applies enough energy to the particles, making the coating removal process very efficient.
  • The old saying “pressure is productivity” holds true when 200 psi is used for fiber optic cable laying. Although many manufacturers of fiber optic cable laying equipment recommend 150 psi, contractors have found that 200 psi allows for faster and better quality work.

Reducing fleet size

Some machines have been designed with the intention of increasing application opportunities with one machine. This is made possible because of a couple of technological advances in compressors. New compressors provide a higher pressure with less volume. Also, new engines increase the power output. Machines are more efficient requiring less horsepower to produce the same amount of air. It also should be noted, however, there is a bonus to this reduced horsepower — a significant reduction in noise level.

One benefit of requiring less volume is the thousands of dollars saved on buying a compressor with less volume. This in turn reduces rental costs for the contractor. But the goal is not to add one more compressor to the fleet for special applications. Some compressors offer a unique feature allowing a 300 cfm machine to be used in low and high-pressure applications.

A new feature called a dual pressure regulator allows one machine to be used for high and low pressure. By flipping a switch, the compressor produces either 100 or 200 psi air. This benefits both contractors and rental houses because the same machine can be used for many applications.

Parts commonality also will save more money for those purchasing this type of compressor. Parts from the machine are interchangeable with the popular size compressors in the medium range class. Parts commonality reduces the need for large amounts of inventory on unique parts and increases productivity of service personnel.

There are also low-fuel shutdown indicators. Some compressors offer both a low fuel alarm and low fuel shutdown. These devices greatly decrease the chance of running out of fuel, a time consuming mistake that causes downtime for the contractor and, too often, an unprofitable service call for the rental center. Low-fuel shutdown indicators keep air from getting into and damaging the fuel pump.

Other standard features intended to increase machine life include a water/fuel separator and an inline fuel filter. Some compressors maintain a fuel tank capacity of nine hours of runtime at 100 percent of volume and pressure. Although it is unlikely any compressor will run at 100 percent for a full shift, this benefit greatly reduces time wasted traveling to fill the tank.

Another standard feature highly requested by rental companies to increase efficiency is glow plugs. The initial cost is greatly offset by the reduced wear on the engine and increase in resale value.

Maximizing fleet life

No argument for increasing productivity can be made without discussing maintenance. Regular servicing of a compressor is expected at regular intervals. Fluids must be changed every 1,000 hours, filters changed every 500 hours and hoses should be inspected every 500 hours of operation. Air ends should be overhauled every 8,000 hours of service. Consult with the manufacturer for engine overhaul guidelines.

Manufactures are also expanding service options to include extended warranty packages to increase the value and life of a machine.

New designs in compressor body construction are also intended to increase the life of the compressor. More formed body parts decrease the number of bolts necessary to build the body. Fewer bolts on the outside minimize corrosion. New designs in grills also offer less corrosion. Oval grill holes, as opposed to square grill holes, eliminate rough corners and corrosion points. This translates into longer life for the compressor and less contaminants taken in through the grill.

All in all compressors keep advancing. By increasing quality through technology and design enhancements the rental house and customer keep getting a better product and ultimately more productivity.

Article provided by Portable Power, an Ingersoll-Rand Business Unit, Mocksville, N.C.