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Impacting Hydraulic Breaker Longevity
Rock has literally been around forever. Breaking rock is still a work in
progress, but the evolution of breaker technology over the years has
made the task considerably easier. New and improved features of
hydraulic breaker attachments have even allowed some breakers to
work in applications where they otherwise could not. These features
directly influence performance and can also have a tremendous
impact on the longevity of a breaker.
The different environments in which breakers must work present a
variety of challenges, almost all of which can be overcome with the
right technology. Noise level regulations and the density of the
material to be broken are just two of many potential issues. While
almost any breaker on the market can accomplish the basic task
of breaking material, not every breaker will have the same service life or perform up to the requirements of a specific job.
Advances in technology have fundamentally set some breakers apart from the rest. The latest available features not only contribute to more efficient production on the job site, but they could also mean the difference between accomplishing the desired result and literally destroying the breaker itself. With so much at stake in demanding breaking applications, it is essential to consider the available technology that today's breakers have to offer.
Easy on the Ears
Breakers are used in many different locations and applications, and therefore varying features of a breaker will be more or less important depending on the site. In many situations, the noise level of the breaker is a major concern. It isn't hard to imagine the noise generated by the constant hammering of a breaker against rock, concrete or any other hard material. There is no mute button to press when it comes to breaking. However, many breakers do have sound suppression systems that will lower sound emissions.
The design of the breaker housing will significantly affect noise output. For example, a box completely wrapped around the breaker's percussion mechanism will essentially act as a muffler. Since openings must remain in the box for maintenance purposes, noise can be reduced further by adding rubber plugs or covers to these openings to seal off sound coming from inside. Other available features are polyurethane wear components, which prevent metal-to-metal contact between the breaker's power cell and box, greatly reducing the vibrations inside the breaker.
When a large breaker is hammering away at rock, perhaps, in a quarry miles from civilization, the noise level may not always matter. But breaking applications also often occur in public places, such as near schools and hospitals. In these situations there may be restrictions on when the work can be performed based on the decibel rating or sound power level of the breaker.
At distances as far as 75 yards, a breaker without sound suppression can still register a volume of at least 85 decibels (about the same as a loud vacuum cleaner or noisy restaurant). With advanced versions of sound suppression, the exact same noise level may be registered only 10 yards away, getting much quieter as the distance from the breaker increases. Having this ability to limit noise allows a breaker to work longer hours in more applications.
Even in cases where no noise restrictions exist, the reduced vibrations from the breaker add to the service life of the machine by reducing wear and tear. The lower volume and diminished vibration going back to the carrier eases the stress on the operator as well.
Holding Power in Check
Not only can breakers produce a lot of noise, but they can also generate an incredible amount of power. While many applications require a breaker's full available force, often situations will arise where only a fraction of that power is needed. Fortunately, technology that automatically manages the power output of the breaker is available.
Many contractors may feel that having more power is always the best policy. But using too much power can cause serious wear and damage to a breaker's components. Breakers are designed so that the tool steel will stay pushed up inside the breaker as a shock wave is delivered through the tool and into the material being broken. If the full power of a heavy-duty breaker is delivered when it far exceeds what's needed in lighter material, the tool can actually fire out from the bottom of the breaker with every blow as it tries to penetrate deep into the material. This causes severe abuse to the tension bolts that hold sections of the breaker together as well as the tool retaining components.
This type of situation can also lead to a blank fire. A blank fire occurs when there is little or no resistance against the tool, but the breaker's internal mechanism still delivers a power blow. The result is that the tool actually has to reach a metal-to-metal stop to prevent it from coming out of the breaker, causing excessive wear.
Power control technology prevents these problems by monitoring the density of the material being broken. For harder materials, it will allow 100 percent of the energy the breaker is capable of producing to be delivered. For lighter material, the system will regulate the breaker's output performance, limiting the machine to half power to reduce or eliminate the chance of a blank fire. The system simply saves a great deal of wear and tear on a breaker.
Starting Off Right
As important as power management is in preventing unnecessary abuse to the breaker, it can also potentially impede the breaker from getting started in some applications. Therefore, start sequence options have been developed to complement power control. This option allows a breaker operator to control whether or not down pressure needs to be applied before the breaker will begin to operate. This feature usually comes with two startup modes from which to choose.
One mode is intended primarily for jobs on firm ground involving breakers capable of producing a lot of force. This mode automatically prevents the breaker from blank firing by requiring that the breaker's tool steel be in contact with solid material before it will start to run. This can be especially helpful in conditions where visibility is poor or nonexistent, such as while breaking underwater. In these cases the operator may not know exactly where contact is being made with the material.
The ability to avoid a blank fire is ideal for a breaker from the standpoint that it prevents unnecessary stress on the breaker's components. On the flip side, however, there are some situations where unstable material must be broken. Because there isn't full contact pressure against the tool, the breaker will not begin to run in the first start sequence mode. However, a second mode in some start sequence systems will allow the breaker to operate and start breaking lighter material without down pressure against the tool.
A breaker's power control system comes back into play in this situation by limiting the breaker's output power to half of its potential. The power continues to be managed until there is enough contact pressure from the material to warrant the use of full power.
Keeping Out the Dirt
Finding a balance between breaking in firm or soft material is certainly a key factor in keeping a breaker in good condition. Another cause for concern arises when a breaker is used in applications with particularly high dust loads. These situations usually require additional protection to keep debris from being ingested into the breaker. This can easily happen when breaking in a horizontal or overhead position, such as during tunneling work.
A lot of the material that is being knocked loose may fly onto the breaker and get ingested through the lower bushing. This is problematic because the debris particles will stick to the grease that is lubricating the tool in that area. The combination of lubricant and aggregate forms an abrasive paste that can greatly accelerate wear.
An advancement in breaker design that counteracts this problem is a sealing system that prevents debris from entering the breaker. Not only does this stop the entry of abrasive and damaging material into the breaker, but it also allows clean lubricant to remain in the lower bushing area longer. Without a system to protect against debris ingestion, lubricant is consumed more quickly and wear bushing life is reduced. The same bushings can last twice as long or more if debris is sealed out.
Furthermore, the percussion piston may experience a shorter life cycle without protection in dusty environments. In fact, if enough abrasive material gets into the breaker, the piston's life may be dramatically shortened.
Grease Is the Word
While outside elements pose the greatest risk to a breaker's durability, the internal mechanisms must be protected as well. The very nature of the components of hydraulic breakers and what they do dictates that most breakers on the planet need consistent lubrication to function properly and avoid breakdowns. However, the method of greasing a breaker can vary.
Some breakers require manual lubrication at set time intervals, usually every two to four hours. The primary disadvantage of manual lubrication is that a breaker may wind up running without lubricant for a short time until it's refilled, which can be very hard on the breaker's components. And because there are so many lubrication points on a breaker, stopping to apply grease also contributes to dreaded downtime.
Taking these drawbacks into account, technology was created to automatically lubricate breakers as they work. Automatic lubrication systems are sometimes mounted to the breaker's carrier. Lubricant is applied through a hose that runs down to the breaker attachment. A carrier-mounted system is certainly more efficient than manual lubrication. The downside is that if a breaker is frequently moved from one carrier to another, it would require a separate system for each machine to which the breaker is mounted.
A more recent development in automatic lubrication technology involves a system that is actually mounted to the breaker, a design that allows the system to go wherever the breaker goes. In addition to taking the responsibility for greasing the breaker out of the operator's hands, a breaker-mounted automatic lubrication system provides a constant and uniform supply of lubrication at the proper intervals, further extending the life of the wear components.
Making the Best of a Bad Break
As a machine is used for more and more hours over its life cycle, it is almost inevitable that at some point a given breaker will encounter a hard section of material that it isn't able to handle with its normal energy output. What happens in this instance is that the energy wave that goes through the tool steel is not powerful enough to split or chip the material to be broken. Instead, the shock wave bounces off of the material and the energy is reflected back up into the breaker. The breaker's piston then changes direction, causing it to back feed hydraulic oil in the breaker and create a spike in the system.
If the piston moves down to deliver a "double hit" at the same time as a recoil wave is moving up the tool steel, the resulting collision can amount to a far greater impact than the breaker's components were designed to withstand. Tools and pistons could conceivably break in this situation.
This type of problem has been addressed through technology that monitors the movement of the piston and thus prevents it from bouncing or double hitting. While this does help prevent damage to the breaker, it doesn't necessarily help the operator finish the job of breaking the hard material.
Another feature implemented on some breakers is energy recovery. This feature takes advantage of the high-pressure accumulator, which is essentially a storage cell that momentarily collects the reflected energy coming back into the breaker. This energy, which is basically a volume of hydraulic oil, is then released during the next blow delivered by the breaker. Furthermore, the energy is released in addition to the breaker's normal power output. The combined energy effort can create performance increases of up to 25 percent in some cases. This boost in impact power may be enough to help break through the tough section of material that created the issue in the first place.
Because the breaker is recycling the energy from the initial bounce-back, it doesn't require any additional effort from the carrier. The adjustment requires no operator input. It occurs automatically as needed but otherwise is turned off. The system effectively takes a potentially devastating situation and instead uses it to the breaker's advantage.
Breakers need every advantage they can get in a world of breaking applications that is loaded with variables. Technology that will maximize a breaker's productivity and keep problems to a minimum is not a figment of an idealist's imagination. It does exist. Breakers lacking this technology simply run a heavy risk of failure, from excessive downtime to not even being able to work on the job in the first place. Meanwhile, in the demanding world of mining, tunneling, trenching, and demolition, the right technology is helping the fittest breakers to not only survive, but to continue to thrive for years to come.
SAI (Soosan America Inc.)
model CB 450