Equipment Focus: Cracking The Code

Features - Feature

Makers of hydraulic hammers and breakers say technological advances have given equipment users a greater range of choices.

March 29, 2011
Curt Harler

Contractors can buy a good breaker without breaking the bank, say makers of such equipment. Whether the job is smashing pavement or wrecking reinforced walls, today’s breaker manufacturers have equipment to fit the job. And, they offer machinery that complies with regulations in an environmentally touchy world, they say.

“Undersize the hammer to the excavator and to the job,” advises Jerry Fifer, tech support manager for Doosan Heavy Attachments, which handles the Tramac product line. “Go with a slightly smaller hammer so you have the weight to hold it down.” Having the power absorbed by the target material – rather than having the power shiver back up the piston – is more efficient. The job might take a bit longer, but the hammer is not exposed to as much fatigue.

“Advancement in hydraulic breaker design has seen vast improvement in the last decade from some premium product manufacturers,” says Kevin Loomis, North American product manager - hydraulic attachments for Atlas Copco Construction Equipment.

That new technology has extended product service life, reduced operating costs and lessened negative impact on the environment.

“Today's recycler should demand the latest advancements in hydraulic breakers, such as the ability for the breaker to automatically adjust breaking power to match the demand of the material being broken,” Loomis says. This translates into longer overall life and more efficient operation, which reduces wear and cost.

Automatic lubrication systems attached directly to the breaker are now available and take the daily maintenance out of the operator’s hands while also providing a more consistent and improved flow of wear, reducing lubrication.

On top of that, local noise restrictions are becoming more prevalent and sound emissions must not be ignored when choosing a breaker today.

Be sure the machine driving the hammer is large enough to haul the hammer around the work site, say manufacturers. More importantly, be sure it will hold the hammer down on the concrete. “The piston drives the hammer through the concrete,” Fifer says. “Without sufficient weight, the piston hits the tool and tries to lift the excavator up.” The result is a vibrating machine. The farther out the boom is stuck, the more leverage the unit has to work against the operator.

“It is really important to have a machine large enough to hold the hammer down and keep it stable,” Fifer adds.

Hammers come in two common configurations: fully hydraulic and nitrogen gas-fired. “Both do the job,” says Fifer, whose company sells both. There can be more maintenance required with gas-fired units, since they have to be recharged, whereas hydraulic units do not. But the gas-fired units typically are less expensive.

“Both types will get you to the same place,” Fifer says. “If it works for you, it’s a good hammer.”

Loomis says there is no calculation that can provide guaranteed performance figures to determine the quantity or size of breaker required. But most breaker manufacturers offer production figures that document typical results of their product across various ranges of material types.

“When reviewing these results, it will be possible to estimate the number of breakers it will require to produce a given amount of processed material per hour,” Loomis says. Each breaker is designed to fit a specific range of carrier such as a skid steer, backhoe or excavator.

Often the breaker selection process will start by reviewing which model will properly fit an existing carrier in the contractor’s fleet. From there, manufacturers’ production figures can be used in combination with consultation from the manufacturers’ representatives to determine if more breakers or larger breakers will provide the desired results.

Contractors who have not had previous experience with a specific breaker may greatly benefit by renting a breaker to get first-hand knowledge of performance and features, Loomis suggests. “A premium breaker manufacturer will be able to facilitate a rental purchase and can often apply a percentage of rental revenue to the purchase price of the breaker,” Loomis says.

The power of a breaker is in the momentum of the piston and the length of its stroke. The most efficient way to break material is to increase the stroke momentum until the material breaks, Fifer says.

An analogy might be driving a nail into a wall to hang a picture. You wouldn’t use a sledge hammer when a 16-ounce hammer would do. On the other hand, it pays to know whether the wall is flimsy wallboard or whether you will be driving into a wooden stud. The same holds true with cracking or crushing demolition material.

Loomis says it is imperative that the breaker is installed on a machine that falls within the published weight range of the specific breaker model. Installing too large of a breaker can create an unstable environment for the operator, which can lead to equipment tipping or structural damage to the carrier, he says. Installing too small of a breaker can lead to structural damage of the breaker and tool breakage.

“After picking a proper breaker to physically fit your carrier, you must next confirm that the hydraulic output of the carrier is sufficient to fulfill the requirement of the breaker without exceeding the maximum value,” Loomis comments. “There is no substitute for an actual flow and pressure test on the carrier to determine if the carrier’s auxiliary hydraulic circuit will be sufficient for your breaker choice,” he says.

Fifer recently was called to a bridge deck job where the demo team was using a 7,500 psi, 600-pound hammer to pound six-inch holes in the decking. He recommended changing to a smaller hammer. The job ran faster since such large holes were not really required. And, the hammers will last longer in such cases, he says.

“Buy a breaker with the flow range to do different things,” Fifer says. “Adjust the flow to the job.” There are units that will self-adjust, he adds.

On a concrete sidewalk cracking project, the machine can run fast. If the job involves hard rock, run the hammer slower. “A good rule of thumb is to give the hammer more dwell-time with each hit,” Fifer says.

All breakers have a flow range and recommended hydraulic pressure for operation. Typically, they are mounted on equipment, like loaders. The flow rate, in gallons per minute (gpm), must be kept within the skid steer’s range. Many smaller skid-steers have a flow range of around 20 gpm, says Fifer. However, large units will have pumps that run anywhere from 40 to 90 gpm.

“You have to cut the flow down to match the breaker,” Fifer says. On most machines hat is easy to do under the dash where the flow rate can be electronically adjusted. Older machines might require flow dividers. A 2,500 psi pressure is typically within the maximum pressure rating of most manufacturers. “Usually, it is not the pressure but the flow that is a concern,” Fifer says.

Noise and dust are the two major environmental concerns with hammers and breakers.

Some manufacturers address the processes at the origin, to limit noise before it is created, while others use systems to reduce the noise after it is produced.

Loomis says his breakers use both approaches. “Our Energy Recovery system smoothes the operation cycle by processing reflected energy in an innovative and controlled process to reduce vibration and ultimately noise, while our VibroSilenced box mounting design provides a suspension system within a sound dampening enclosure.”

Many hammers today are cradle-mounted. Those which fit inside a cradle can be silenced. Basically, they are designed so that the noise is muffled within the cradle.

Dust is another story. There are two approaches. If the material must be broken on-site, keeping the area hosed down so the dust is suppressed is advised. The use of mist-makers is another way to suppress suspended dust. Those approaches do not always work in a downtown area where there are many passers-by and the dust seems to blow everywhere.

One way to proceed in those cases is to take that material off-site to a location where it can be broken without environmental hazard.

“Limiting the ingestion of dust into a breaker will reduce wear and maximize component life,” Loomis says. Standard systems on specific Atlas Copco breaker models use a process of collecting clean air from the top of the breaker and processing it through the impact chamber to produce air flushing at a bushing area near the tip of the tool. This is designed to keep dust out of the cavity.

An optional dust protector system is available on specific breakers that provides a two-stage level of dust protection by adding multiple seal surfaces to actively prevent the ingestion of dust. For the most extreme dust intensive environments, internal water spray nozzles to stop dust at the source are available, as are carrier-mounted hydraulic air compression systems.

With the constant growth in brands of hydraulic breakers available today, a savvy buyer needs to compare which options are available on a base model as compared to options that must be purchased additionally, Loomis says.

“This can greatly skew the impression of the overall investment, like a fully-loaded vehicle compared to a stripped down model,” says Loomis. “Don’t let the purchase price be the only factor in the buying decision. The cost of operation and resale value must be carefully considered as well.”

Loomis suggests a buyer be sure to compare apples to apples in various brands by asking to see the AEM (Association of Equipment Manufacturers)-certified energy ratings for the breaker in question. “Often, manufactures will publish a foot-pound class which is an arbitrary number that the manufacturer assigns to a model, whereas the AEM energy rating is an actual, certified measurement allowing consumers to make an educated comparison based on fact,” Loomis concludes.