The vibratory round separator is ideal for separating solids from liquids or segregating dry materials into various particle sizes. Depending on the size of the machine, as many as four screen decks can be incorporated into a single separator for simultaneous classification into five fractions. Most round separator manufacturers offer machines with screen diameters varying between 18 and 100 in.
These versatile machines are critical for processing in a vast number of industries, and thus need to remain functional as not to cause stoppages in the process. Equipment failure during production can be very costly when material reprocessing is required. And downtime can cause a company to lose profits in lost production. Therefore, keeping the equipment healthy is important for the efficiency and profitability of any process.
A cursory inspection of your separator and its components should be performed daily, while a more complete, systematic inspection should be executed weekly to help prevent larger problems that will happen should a component failure occur.
There are several components of a round separator that are critical to making sure your separator continues to perform in good working order. If something goes wrong with the separator and production must stop, the key to minimizing downtime is making sure that you are stocking these spare components.
There are plenty of replaceable pieces to a round separator, but none more common or critical than the screens inside the separator. A torn or otherwise compromised screen can result in significant costs to deal with reprocessing, scrapping, or even recalling off-spec product. When a screen tears, coarse material that should be rejected by the screen can now pass through it. The consequences can be serious. In many applications, a screen is used to remove objectionable or even hazardous coarse material. Once the screen tears, there is no longer any assurance that such materials will be rejected.
However, any screen’s service life can be maximized through proper selection and maintenance. For example, screen mesh is available in several different wire diameters for a given opening, and often service life can be extended simply by selecting a mesh with a heavier wire diameter.
No matter what mesh is selected for the process, practically all screens will fail if left to operate indefinitely. Therefore, a spare screen is crucial to any process. Having a spare screen will ensure minimal downtime because of screen failure. If a spare is not available, your process could be down for an extended period before receiving a replacement.
Many applications encounter screen blinding during processing. Screen blinding occurs when the screen mesh openings are blocked or closed by the material that is being screened. Near-size particles become trapped or build up on the wires effectively blocking the screen openings preventing further material from passing through the screen. This is a common screening problem that may be easily fixed with screen-cleaning devices.
To counter screen blinding, one of the most common equipment features to use are sliders and balls in the form of self-cleaning kits and ball trays. These components are used to shear off (sliders) or tap out (balls) trapped near-size material from the underside of the screen.
Anti-blinding devices, such as sliders and/or balls, are wear components that lose their effectiveness over time. Proper monitoring and maintenance of such devices will keep screens clear and free from blinding. Because these components wear out over time and can be easily monitored, they are not as critical to keeping on-hand for replacement as other components. But having them available for replacement would never be discouraged.
The motor is considered the heart of the vibratory round separator. Like the screen, the motor is a critical component. Without the motor, there would be no motion. Without motion, there would be no separation. It’s that simple. It is essential to take proper care of the motor, and, in addition, have a backup plan.
The key detail to keep in mind when caring for your motor is lubrication. When dealing with manual greasing, the questions are always going to be “What?”, “When?”, and “How much?”
What? – The grease that will go into your motor will depend on the motor type and the application. There are many types of greases available, and most separator manufacturers will offer the most common along with high-temperature and food-grade greases for special applications. Make sure the correct grease is being used for your motor and for your application. Putting the wrong grease in the motor will increase the risk of premature bearing failure and force you to replace the motor.
When? – Each motor in a vibratory separator should have a schedule based on usage hours as to how often grease must be added to the motor. Users should always consult the operator’s manual to make sure the schedule is followed. Lack of lubricating the motor will increase the risk of motor failure.
How much? – The operator’s manual should also cover how much grease is needed when adding it to the motor. Under-greasing will not provide enough lubrication to the bearings which will eventually cause motor failure.
Over-greasing could be even more harmful to the motor. This can lead to higher operating temperatures or collapsed seals that can invade the motor’s electric winding components and cause failure. Inside the bearing, over-greasing can also cause improper mixing of the lubricant resulting in the separation of the oil from the thickener. This separation can cook the thickener into a hardened paste that can block new grease from reaching important elements of the bearing that can also cause failure. For these reasons, it is important to dispense the appropriate amount of grease to your motor.
An alternative option to manual greasing is an automatic grease lubricator. Most separator manufacturers offer automatic lubricators that can help preserve the life of the motor. These automatic lubricators are a perfect solution providing the right grease, at the right time, in the right amount promoting ease and consistency of maintenance and longer bearing life. These auto-lubricators assure bearings are being lubricated correctly, taking the guesswork out of “When?” and “How much?”.
Taking care of your motor is crucial to keeping your process running. But no motor is going to last forever. Eventually, the motor bearings are going to fail. To avert a shutdown of the separator for any long period of time, a spare motor should be kept on-hand. Keeping a spare motor on-hand assures limited downtime should motor failure occur.
Spout connectors and screen gaskets are the rubber components within a round separator. As with all rubber products, with age components tend to dry out, become brittle, and begin to crack. When this happens with screen gaskets, the seal becomes compromised and material tends to work its way around the gaskets. What occurs is material leaks outside of the separator or, worse, material bypasses the top screen and making its way down to the screen below the compromised gasket. This will cause either the loss of good material or reject material getting into the good material. Either way, the efficiency of the separator will be compromised.
To avoid this issue, make sure to replace your gaskets regularly in accordance with the manufacturer’s recommendations.
Spout connectors also have a tendency of drying out and cracking. Material is continually running through the spout connectors and the wear on them can be severe. Additionally--due to the motion of the separator--the connectors are continuously flexing which increases the wear. Cracked or torn spout connectors can cause major losses of material, which could cause problems by allowing the material into the manufacturing environment.
To avoid the problems that can occur with faulty rubber goods, it is recommended to check them periodically for wear and cracking and identify forthcoming failures. Extra gaskets and spout connectors should be kept on-hand for timely replacement.
Springs and Spools
Springs are another component on a round separator that will wear over time and need replacement. When a spring is worn, it will be noticeable by the spring being compressed, bent, or broken. When spring replacement is required, it is best to replace the entire set of springs on the separator so that the mechanical energy of the springs is equal.
Spools are the components that hold the springs in place between the base and the frames. These pieces tend to wear down over time and will need replacement.
It is recommended to inspect your springs and spools daily and to keep on-hand a spare set for your separator to minimize the downtime should one or more of these components become compromised.
The clamp rings are the mechanisms that hold the screens and frames together within a round separator. These clamps need to be tightened to a specified torque level. Each manufacturer may have a different foot-pound value. Thus, the operator’s manual should be consulted for that value as well as the proper method of installment.
Over-tightening a clamp could cause damage to the clamp, nut, or bolt. Under-tightening a clamp will cause problems with the stability of the frames and screens. So be sure to follow the installment instructions, closely considering the suggested torque values. The more the clamps are untightened and retightened, the more wear you’re putting on the component. So, if the separator is disassembled and reassemble often, it is important to inspect the clamps regularly to preemptively determine any indication of wear to the component. Catching this early will allow you to replace the clamp, reducing the chances of clamp failure and, thus, downtime for the separator.
A center-tie-down is used to stabilize the screen, reducing the whipping action of the mesh caused by the vibration from the motor within the round separator. These components quite often need to be replaced.
Some center-tie-downs have left-hand threads between the components. Because of this, operators will often attempt to force the cap onto the pedestal, breaking the threads on the components. This will prompt the need to replace the tie-down. Additionally, if the material is abrasive or it is a high-temperature application, the components of the center-tie-down will wear. Once the integrity of the center-tie-down is compromised, a full replacement is required. Keeping a spare center-tie-down could prevent a lengthy downtime of the separator.
As you can see, there are numerous wearable components in a vibratory round separator. Correctly maintaining those components will save your company in many ways: material reprocessing costs, lost production due to downtime, maintenance costs, and more.
Properly maintaining your separators and keeping the appropriate spare parts on-hand in case of component failure will increase your odds of sustaining a continuous operation. Many manufacturers will offer spare parts kits that include most of the items mentioned to help you ward off any failure induced downtime and help keep your process more efficient and profitable.
For more information, contact SWECO (Florence, KY) at 859-283-8400 or visit www.sweco.com.