After securing the chain around the rock in the crushing chamber, a man still in the chamber tells the loader operator to lift the rock. The operator lifts it about three feet into the air when, suddenly, the chain snaps. The rock plunges back into the crusher, missing the mans leg by a matter of inches.
Stories like these involving crusher blockages unfortunately still happen in the industry. Fortunately, this particular event unfolded without an injury. Still, an inch or two one way or another can often make the difference between a safe trip home from work and no trip home at all.
Ive heard and read stories about guys getting killed, says Paul Smith, international marketing manager for Astecs Aggregate and Mining Group. These machines can be deadly. After 20 years of climbing into quarries, I still keep my head on a swivel.
Aggregate producers cant control all of the factors that lead to accidents related to crusher blockages. They can, however, create a work environment and culture that best positions people to return home from work every day.
To Smith, one of the key factors that should be addressed related to crusher safety is a companys workforce. A number of people operating and working around crushing equipment dont have the adequate experience, he says. Producers and recyclers sometimes turn to a transient workforce, and that can present problems.
Our industry is so much about tribal knowledge, Smith says. Were still relying on grandpa to educate a grandson to operate a plant. Or, were adding crews to do short-time jobs and leaning on temporary labor.
Effective operators and contractors tend to put one of their best teams on crusher duty because they realize production starts and stops with these workers. But teams often consist of just two people a loader operator and a plant operator. A third person can make a difference in a number of areas, Smith says.
Its a luxury to have a third guy, but I would argue that having a guy at $15 an hour on the ground pays for itself, Smith says. Maybe this is the new guy whos being trained, or its the boss son. I do know that if that guy prevents a cone crusher from going down and losing a thrust bearing once or twice a year, hes going to pay for himself.
Operating a crusher at 90 percent efficiency versus 80 percent or less will boost a companys bottom line, as well. A third person focused on the crushing operation should improve efficiency, Smith adds.
Use a 30-[in.] x 54-[in.] jaw for example, he says. Take 80 percent of the first number thats 24 in. Thats the lump size you want to put into that crusher. Size the crusher to the size of the material. If you want to have max production, youll pay attention to those rules.
The workforce isnt the only area producers can focus on to avoid crusher blockages and enhance safety related to crushers. The most economical form of crushing is blasting, Smith says, so tighten shot patterns to reduce the amount of oversized material.
Its very practical to have a rock breaker right next to the primary crusher, says Ilkka Somero, Metsos product manager for jaw crushers. Often, you dont even need to break the rocks. Its enough to pull or push the rocks a little bit. Then the materials flow again.
Breakers and hydraulic hammers attached to excavators are also useful to reduce oversized material that can be loaded into a crusher, Somero adds. Smith suggests prepping material with a grizzly feeder if possible, as well.
Still, theres an additional cost associated with a grizzly, he says, as there is with a breaker. A sensor is yet another option for operators to alert themselves when oversized material is present in the feeder. Sensors obviously wont pull a large rock from the crusher for you, though.
They still cause the operator to react, Smith says. The oversized piece of material still has to be extracted. You have to shut down the plant. Its not a perfect solution, but it does help you from plugging the crusher.
Crusher design is another area some manufacturers have focused on to help producers and recyclers avoid blockages and create safer work environments. Sandvik, for example, addresses the blockage issue with its Prisec horizontal shaft impact (HSI) crusher.
According to Rowan Dallimore, an impact crusher manager at Sandvik, the Prisec model can be cleared while the crusher is running. To clear blockages, Dallimore says users stop the feeder and activate the hydraulic system. This lifts either the first or second curtain, allowing a blockage to pass through the crusher.
Once the blockage has been cleared the curtain can be lowered, and they will reset automatically into the previously set position with the hydraulic system switched off and the feed re-started by the crusher, says Dallimore, who estimates that the Prisec clears about 90 percent of blockages without having to stop the crusher. All of this is done with the crusher still running and no operator intervention inside the crusher.
Such a system saves users considerable time, too. Clearing a blocked crusher can take an hour or more, Dallimore says. He estimates that a typical blockage occurs in a stationary plant between five and six times a year, with mobile crushers experiencing even more blockages.
With the recycling business we never know what were going to crush within reason, Dallimore says. When its on a tracked mobile unit, they can be on one site one week and on a completely different site crushing completely different material the next week.
These dont necessarily behave well in a crusher, Smith says. You have the potential to rip belts; for stuff to get hung up at the bottom of the crusher. Or, it might block the discharge part of the crusher and you get buildup in that area.
Every producer is encouraged when they start up a new plant to baby the plant for a period of time, he says. See how the equipment handles that material. If they move it to a second location, things like moisture index change.
Ive read a story about a guy inside an impact crusher on a recycle job, Smith says. The door of the impactor was open, and he was inside it cleaning off some of the asphalt buildup. While in there, he motioned the guy to turn the impactor a little bit. When the guy did that the impactor came up to full speed, and the guy got chewed up in a matter of seconds.
Some of these machines behave like Swiss watches: They require a certain amount of oil, Smith says. We do a lot of things to safeguard and keep bad things from happening, but you still need to find, hire and train the right people. We really need to do that.
RUBBLE MASTER was founded in 1991 with the idea to enable contractors to recycle materials on-site without needing the same material processing experience as aggregate producers. The machines had to be compact with high throughput, easy to use and safe, so that on-site crushing became an attractive business to the contractor market. Since then, we have grown with our customers and today RUBBLE MASTER is the global market leader in mobile Compact Crushers.
RM NEXT elevates the most easy to use material processing equipment to a new level of simplicity, safety and performance. RM's refined machine controls are designed to give you the most out of your crusher or screen. Make light work out of daily maintenance. Troubleshoot issues faster and with confidence. And put more product on the ground.
RM Compact Crushers with the iconic low-mount engine design set the standard in mobile on-site crushing. Today's jobsites and workforce change rapidly. RUBBLE MASTER keeps thinking of new ways to make your life easier, so that you can achieve a high output without the hassle - growing your business.
As a result of the great development of the basic construction and the reconstruction of the towns and the rapid rise of the high-rise buildings, the old-style buildings die out, and the waste of the construction wastes is directly buried without treatment, Then it will cause long-lasting harm to our living environment. Crusher plant can deal with construction wastes well.
Our company, a professional construction machinery manufacturer in China, provides top quality crushing plant, asphalt plant, concrete batching plant for sale. If you are interested, just contact with us now!
Compared with the mobile crushing plant, the stationary crushing screen plant has no tires. In view of the present situation of construction waste treatment in our country, crushing plant has strong advantages, but with the increasing maturity of construction waste disposal market, it will slowly be transformed into fixed crushing plant, that is to say, mobile crushing station is transitional equipment, and slowly will be converted into fixed type.
It is mainly used for fields like metallurgical, chemical, building material, hydro-power that needs material processing, especially for highway, railway, hydro-power with the operation of mobile stone. Customers can choose multiple configuration according to types of raw material, size and finished material requirements.
Mobile crusher plant can not only reduce the cost of transportation, but also cooperate with brick making machine to make the raw material into finished products at one time. With the increasing market demand, various types of crushing plant are needed, such as jaw mobile crushing plant, tire mobile crushing plant and other types. These plants can produce product with high quality, high crushing ratio, reliable performance.
Vibration feeder takes eccentric shaft as excitation source, gear transmission, low noise, stable operation, long life, and it can screen fine material in advance to make crusher more efficient. Adjust the gap grid design to prevent material blockage. Customers can selectively install speed-regulating motor, easy to control the feed quantity, no need for frequent start-up of the motor.
Circular vibrating screen is a kind of screening machine, which mainly produces centrifugal inertia force (excitation force) with radial variation because of the unbalanced rotation of the vibrating wheel of the exciter. Itdrives the screen box and makes the screen vibrate. The trajectory of the screen frame is elliptical. The material on the screen is thrown up by the upward movement of the screen surface, and then falls back to the screen surface after a distance. In this way, the screening is completed in the process of moving from the feed end to the discharge end. The amplitude of the vibrating screen can be adjusted by changing the weight and position of the counterweight.
As far as the counterattack crusher is concerned, the rotor rotates at high speed under the drive of the motor while working, and the material entered from the feed port is hit by the plate hammer on the rotor, which is broken by the high speed impact of the plate hammer; the broken material is hit back on the liner and broken again; later, it is discharged from the outlet. Adjusting the gap between counterattack frame and rotor frame can change the particle size and shape of material.
The material is uniformly transported into the crusher through the feeder, and after the crusher is initially broken, the closed circuit system is formed by the circular vibrating screen to realize the cyclic crushing of the material, and the material in accordance with the grain size requirements is output by the conveyor, so as to achieve the production purpose.
Before the operation, check whether the supporting equipment can run normally, such as crusher, feeder, and so on, whether the connection of these supporting equipment is loose or falling off, and whether the transmission device is abnormal. Especially the crusher, ensure that there is no residual materials in the crusher. In addition, because the working environment of the stone crushing plant is complex, the tire of the mobile crushing station is a vulnerable part, the user should also check whether the tires can work normally before carrying out the operation, so as to ensure the overall performance and normal operation.
The circuit problem of the whole machine in the operation process is a problem that the user needs to pay attention to. If there are special noises, odors or sparks in the working process, stop the operation immediately, maintain in time and never work by force. Otherwise, the whole equipment and motor may be damaged, and it is easy to cause inestimable losses to the user.
Before the stop of the crushing plant, the user must ensure that all the equipment can stop after all the materials are discharged. After the mobile crusher stops, the user should also check the circuit of the equipment, the supporting equipment and lubrication in time. For any abnormal condition, repair and maintain in time. In addition, due to the complexity of the working environment of the aggregate crushing plant, users need to clean and maintain the equipment in time after operation.Get in Touch with Mechanic