April 9th, 2015
How to Prevent Build-Up, Avoid Engine Overheat
As we approach warmer months, producers should take the time to review the effects of processing recycled asphalt pavement (RAP) on an engine’s cooling ability.
Asphalt dust contains oil, which in heated conditions will emulsify to a liquid form mixed with aggregate dust. The asphalt dust then sticks to the cooling fins of the radiator and begins to build dramatically, affecting the heat exchange ability of the radiator. This eventually causes the engine to overheat.
The “heated condition” is caused by a number of factors, the first being the ambient temperature. The warmer the temperature, the more oil will stick. The other variable is the radiator itself. Even at engine operating temperature, the radiator is very warm. And even under normal operating conditions, the radiator is warm enough to attract the oil.
Those operating in higher elevations have yet another factor to consider – the volume of air flow. Air flow is commonly measured and identified in cubic feet per minute (CFM). At higher elevations, the air velocity is affected due to thinner air. Many believe that a larger radiator package is the answer to this, as it gives your radiator increased cooling surface area to perform the same cooling function requirement a smaller radiator package can achieve at lower elevations. We at KPI-JCI and Astec Mobile Screens agree, and have addressed these conditions by oversizing our radiator packages to accommodate higher elevations. The current designs of the cooling packages are at a capacity rate of between 120-140 degree ambient temperature ranges (depending on engine size), which provides the flexibility to operate at higher elevations.
With that said, larger radiators are not immune to asphalt build-up. To combat the build-up issue, a strict maintenance regiment is necessary. Staying ahead of the build-up is the only effective way to accomplish this. Remember, even a light coating can be an issue and is often not visible during an inspection. So what can you do?
- The first thing to do is to perform a daily inspection of the radiator. This can be accomplished during start-up examinations like checking the oil and inspecting belts and hoses. Pay special attention to the corners of the radiator, as build-up tends to migrate to these areas.
- The second is to perform a daily cleaning of the radiator. We recommend a radiator cleaner specifically designed for asphalt cleaning. Our operations and maintenance manuals list some of these cleaners that we have extensively tested and have found to be safe and effective. These cleaners were recommended by our dealers, who saw them work firsthand with their customers in the field.
The top cleaners we recommend are Astec Excel Clean HD (no affiliation with Astec Industries, our parent corporation), Citrus King and Citrus Fullback™.
To clean the radiator, you must first begin on a cold radiator with the engine shut off. Apply the selected cleaner with a suitable applicator such as a high-quality garden sprayer. Allow it to soak for 10-20 minutes, and then rinse thoroughly with cold water from a pressure washer or garden hose. You may need to repeat the cleaning process more than once, depending on the severity of the build-up.
The key to removing build-up is to not wait until build-up is visible, as this will require you to physically remove the build-up before a cleaner can work. Remember to use care when using a pressure washer so radiator fins are not damaged. Once the cleaning is complete, compressed air should be used to remove the water so the dust does not get trapped or retained on the wet radiator.
Radiators that have been removed from the equipment and taken to a radiator shop to be professionally cleaned will still have build-up, especially toward the center of the core. Having the radiator professionally cleaned is often not enough. If the cleaners I’ve suggested are used and the recommended cleaning method is conducted daily, it will prevent overheating issues and the need to remove the radiator for a professional cleaning.
Two other methods to prevent build-up include positioning the equipment so wind blows dust away from the radiator and using dust suppression. Dust suppression is often not an option, however, as the volume of moisture is usually not admissible in most spec product requirements.
The key ingredient in preventing build-up is to stay proactive rather than reactive in your maintenance protocols. This is the best way to keep your operation running smoothly. For more information on cleaning procedures, contact our service department at 1-800-532-9311.
February 17th, 2015
Top Ways to Improve Wear Part Life
Recently, I was asked the best way to prolong the life of wear parts, specifically HSI blow bars, jaw dies, VSI parts and cone liners. Producers often want to know how many hours can be logged or how many tons of material can be produced before having to replace wear parts. The answer is the same every time: It depends on each operation and application.
There are a number of variables to examine when considering wear parts life, including:
- Feed size. By feeding too large of material or producing too many fines, producers can cause damage to a crusher and dramatically affect throughput production and wear parts life. Using screens to separate the material so that material is at product size, near size or smaller prevents the material from getting reintroduced into the crusher and helps prevent accelerated wear.
- High-quality parts. Using quality OEM wear parts that fit your crusher and application can also prolong wear life. Using after-market or pirated parts can have warranty implications if the use of these parts causes any damage to the crusher.
- Crusher settings and speeds. Crusher settings and speeds can change the outcome of single pass crushing. Improving the efficiency of a crusher can reduce wear and extend wear part longevity.
- Dust suppression. Water is very abrasive and is often the necessary evil, as it has both a health and an environmental impact. Using dust suppression can have positive results if the nozzle type and placement, pressure and volume are correct and meet the goal for dust control. Nozzle placement is very critical for wear parts life. If nozzle placement is incorrect, it can accelerate wear.
- Composition of material. The natural characteristics of material have an impact of wear parts longevity as well. The characteristics include chemical composition, hardness and abrasiveness. Although producers cannot change the material characteristics, they can educate themselves. I often hear from producers that their rock is really abrasive or very hard, but when asked, they don’t know exactly how abrasive or hard the material is. Knowing the exact characteristics of material can empower producers to select the best wear parts for their operations.
The best way to learn about material characteristics is to have samples tested. These tests include:
- A crush test. This determines how friable the rock is. A crush test provides you with information on how much product tonnage you can make in a single pass, depending on your gradation requirements. If the material can be crushed in a single pass, the wear parts only see the material once, thus prolonging the wear parts life.
- The Burbank Abrasion test. This test demonstrates how abrasive material is on steel parts, which enables producers to select the best wear parts for their equipment.
- A chemical analysis. This determines the chemical composition of the rock, which defines the amount of silica oxide, iron oxide and aluminum oxide present in the material. This test provides producers with the percentage of silica present in material, or as we call it, percentage hard parts.
- A compression test. This test determines the psi (pounds per square inch) strength of the rock. In other words, how much energy is required to break the rock? This test is especially targeted for jaw and cone crushers and will help determine your closed-side-setting (CSS) and reduction ratio.
By considering all of these variables, producers can realize significant savings when it comes to wear parts and production. Of course, it all boils down to education. By regularly attending factory training and consulting factory experts, producers can make the right choices to improve their operations. Taking time to invest in education will always help producers save money and improve the efficiency of their operations by eliminating the downtime associated with uninformed choices. We all benefit from ongoing training, regardless of our role in a business.
November 13th, 2014
Top Three Benefits to Pre-Ordering Parts
Analyzing your operation’s wear part needs is a crucial step in keeping equipment up and running throughout the year. There are numerous benefits to pre-ordering the wear parts you need before you need them – here are the top three:
- Guaranteed product availability and reduced downtime. By pre-ordering, you guarantee that the wear parts are available the moment you need them. Pre-ordering is especially important if you require a unique configuration or non-standard alloy. For example, KPI-JCI and Astec Mobile Screens stocks cone liners with 18 percent manganese content. If your preference is for a 14 percent or 21 percent alloy, lead times can be up to 16 weeks from the date of order. When your machines aren’t crushing, you’re not making money. By pre-ordering, you can reduce unplanned downtime and the loss of revenue that comes with it.
- Knowledge of cost. By ordering parts before you need them, you will know the cost upfront and won’t waste valuable time trying to price shop. Pre-ordering also helps you avoid expensive expediting charges and other unexpected surprises that can arise from waiting until the last minute. You can’t crush without wear liners, and pre-ordering removes that as a worry during the height of the crushing season when so much else requires your attention.
- Highest quality parts available. When it comes to crusher liners, poor quality can have several consequences, the most obvious being that liners wear faster than they should. If you’re changing manganese more often, that means you are down more often, paying more in labor costs to change those liners, and producing less. Discount suppliers may also leave you hanging if the parts you bought don’t perform as advertised. At KPI-JCI and Astec Mobile Screens, quality is extremely important in all that we do. We’re original equipment manufacturers and we stand behind all of our products like an OEM should, wear parts included. We continue to work hard to provide high-quality wear components that are also affordable. We’d rather make that investment up front so you don’t pay the price later.
Every operation has different needs, which is why the best way to plan ahead is to work with your local authorized dealer to put together a forecast. Look at the current operating plan, review historical use and consider any potential changes to future operations. Factory parts sales representatives are also a valuable resource in developing a plan by sharing best practices or helping design in flexibility to meet any unique challenges. Make it a team effort, because you have people ready and willing to help.
Contact your authorized KPI-JCI and Astec Mobile Screens dealer today to take advantage of its parts pre-order program.
April 7th, 2014
Top Ways to Reduce Wear on a VSI
When it comes to preventing wear in a vertical shaft impactor, consider these top six tips:
- No steel or metal allowed in the VSI. A metal detector or magnet is highly recommended. A metal detector attached to the feed conveyor works best as it detects stainless steel and items that a magnet will not pick up.
- Check the size. Large rocks must not exceed the mass noted in the manufacturer manual. Top size, as noted in the manual, should never be exceeded. More importantly, however, is the largest allowable mass of a single rock in the input feed. An individual rock should not weigh more than specified in the manual.
- Low feed rates. A less-than-capacity feed rate or inconsistent feed rate will cause abnormal wear and increase the risk of carbide breakage. Ideally, there will be a smooth and uninterrupted flow of rock through the crusher. Choke feeding the crusher provides a smoother flow. A low feed rate results in a higher wear cost per ton.
- Minimize water, particularly in the crusher feed. Water can create abnormal wear traits. Eliminating any free water will significantly increase the life of the wear parts of the VSI.
- Install a screen. Screening increases crushing efficiency and reduces wear costs. Screening prior to the VSI will ensure the proper feed size. In a closed-circuit system, effiecint screening after the VSI will remove sized product and decrease wear costs.
- Feed Tube Adjustment. The feed tube should be properly adjusted within 3/8” of the top of the rotor to ensure proper feed delivery into the rotor. This keeps rock from wearing the top of the rotor and improves crushing efficiency.
March 26th, 2014
Top Three Rules for Maintaining a Jaw Crusher
When it comes to maintaining a jaw crusher and securing the most uptime possible, the key is to develop a proactive preventive care program and become properly trained on the equipment.
While producers are sometimes solely focused on one specific part of an operation — like how large material can be and still be fed into a crusher — what they should be concerned about is how much production can be achieved and the best way to achieve it. That all boils down to maintenance and education. But maintenance is far more extensive than just greasing bearings and miscellaneous housekeeping.
Because of the violent nature of a jaw crusher, the equipment — regardless of application or manufacturer — will fail at some point without preventive care. But a proper maintenance program can help producers avoid costly breakdowns by repairing problems in their infancy. This could be something as minor as a loose or missing bolt, a broken weld, a loose belt, or a buildup of material that is allowed to remain. When taken care of daily, they remain small issues that can be immediately resolved to avoid downtime, but, over time, they can affect the longevity of the equipment.
While new technology can greatly enhance the efficiency of an operation, it can also add a challenge to those who have not been exposed to it. The following these guidelines can help extend the lifespan of your equipment:
- Avoid oversized feed. To establish a preventive care program that will extend the lifespan of a jaw crusher, producers must go beyond greasing bearings daily and consider the application of equipment. Because the jaw crusher is most often the primary crusher in a quarry or recycling operation, it is asked to perform the most difficult stage of product reduction. It is too often misapplied by feeding too large of material, however, which creates loss of production and the potential to damage the crusher. When an oversized rock is introduced into the jaw but is too large to fit into the chamber, it causes an interruption in crushing, which equals no production. A general rule of thumb is to keep the maximum feed size under 80 percent of the jaw opening or gap as measured from the top of the stationary die to the top of the moving die.
- Keep fines manageable. Although too large of material can cause problems for the producer, too many fines can also affect crushing performance. An excess of fine material will fill in all of the voids, which are necessary for the material that is being crushed to expand into. This creates an event called compaction. Compaction amplifies the forces in the crushing chamber, up to five times the normal crushing forces. As with any force that is generated, the energy must find a point of release, which is usually in the jaw base structure or in the shaft and bearings. Over time, this can cause damage. Excessive amounts of fine material also limit production because these fines are taking the place of otherwise crushable larger rock. Compaction can also be caused by improper use of the jaw die or plates. The corrugations of the jaw dies are crucial to the jaw performance, as the corrugations provide the expansion room needed as well as the leverage required to break the rock. Jaw dies should be flipped or replaced once the remaining corrugations get to about 20 percent of their beginning dimensions or irregular wear is detected. The wear of a jaw die should be gauged by the remaining corrugations at the bottom, not the overall weight of the jaw die itself.
- Aim for attrition crushing. If the proper feed size is introduced into the jaw and the jaw die maintenance is performed as recommended, the result will be a higher output, and true attrition crushing will take place. Attrition crushing, or rock-on-rock crushing, helps with output gradations and improves wear cost for the producer, as more of the wear takes place on the rock rather than the jaw dies.
As with all crushers, the maintenance of a crusher depends on how it is applied and taking a proactive approach to maintenance items like wear parts. Replacing wear parts before they are worn out costs less and improves the crusher’s performance, ultimately saving money, increasing uptime, and providing crusher longevity.
Although the fundamentals of jaw crusher maintenance apply to all jaw crushers, it is important to consider each scenario according to each specific producer when it comes to preventive care. Every producer needs to consider what he can do to improve his situation by adding to or developing a program that will work for his specific needs. There are no two identical applications, both in material and in people themselves. But there are similarities that can be the foundation for building a good maintenance program, so it is important to remain flexible. Keeping an open mind to suggestions may save you money and make you more profitable. It also serves as a morale booster to the employees asked to operate and maintain the equipment, and maintaining good employees will help in assuring that proper maintenance is being performed.
For more information about maintaining jaw crushers, visit Aggregates Manager's website for a detailed article. To contact KPI-JCI and Astec Mobile Screens' Field Service Representative Wade Lippert directly, e-mail him at email@example.com.