December 2, 2011
Pumps need regular maintenance and attention to continue running smoothly and efficiently.
by Thomas Aldridge
How many of us have gotten into our car for a quick run to the grocery store, and tried to start it only to hear a click, click, click? Anyone who has experienced this has learned that the car battery needs to be replaced every few years. We all know that we have to do other vehicle maintenance, such as oil changes, filters, lights, etc., on a regular basis as well. But what does it cost us if we don’t perform this maintenance — a delay and maybe some money while the repairs are made?
As an operator/owner of a quarry or a mine, we are faced with these same issues every day with all of our equipment — especially pumping equipment. Picture a pump on the site as the battery in the example above. What happens when that pump goes bad and stops the operation at the plant? How quickly do those lost minutes add up in time and cost? Just like proper maintenance on our personal vehicles, the pumps that we work with need regular maintenance and attention, too.
But where do we start?
Just like the start of the song “Do Re Mi,” let’s start at the very beginning. For any piece of equipment to be maintained properly, especially a pump, the first step is the selection of the “proper” pump. Part of this selection comes from the flow expectations and the head pressure necessary to overcome the system resistance. Is the pump going to be on a fixed system and maintain flow or pressure, or is it a utility pump that will be moved throughout the plant or site for flood control? When we choose a battery for our vehicle, we look at the cold-cranking amps and the size to make sure we are putting the right battery in.
The use of the pump is also a key factor. Knowledge of the application and the performance expectations help to make sure the pump meets the pumping needs of the engineering team, and knowledge of the maintenance meets the reliability needs of the operations team.
And what do we look for?
In a nutshell, pumps are mechanical equipment that are highly cyclical, so loading conditions have a significant impact on the maintenance requirements. And based on statistical reliability, for any piece of equipment, the question is not if it will fail, but when. We know that our battery will not last forever, so we have to prepare for when it needs attention. For pumps, preventive and regular maintenance is what helps to increase the life of the equipment.
A primary factor in appropriate maintenance is familiarity with the equipment and the application where it is used. You can tell a lot about equipment by looking and listening. Just like a doctor, scrutinize its performance over time and identify differences that occur from when the pump operated new versus how it acts over time. In most cases, the symptoms will show themselves in noise, vibration, or heat. When your car takes a little extra time to start or the lights seem dim, you know it may be time to check the battery.
The next basic maintenance check is to inspect for leaks and inspect the general wear parts. Maintain your fluid levels. These are items that can and should be done every day. A large number of maintenance failures are the result of easily fixed problems. Replacement wear parts should be kept on hand, and a regular program used to inspect and maintain them should be implemented. It can be as simple as brushing corrosion from your battery terminals.
Another maintenance factor in a mine or quarry application is the damage caused by abrasive materials. Are you pumping fine solids or slurries that erode the material and damage lip seals or mechanical seals? It is important to check the compatibility of the materials of construction and the materials being pumped to make sure they fit. Wear rings and wear plates should be adjusted periodically to keep the efficiency of the pump where it should be. Impellers should be inspected for damages. If abrasive material is a factor, be sure to use easily repaired or replaced materials. A fabricated component is sometimes easier to weld and repair than a casting that will require special welding materials or techniques.
The most frequently addressed area for maintenance is seals and bearings. They should be properly lubricated. Watch them for signs of heat and overloading. A bearing problem can amplify and result in additional problems with other parts of the system. Inspect drive-system components on a regular basis. Belts and sheaves are in constant contact with one another and wear over time. Keys can shear. Elastomeric drive components can be impacted by the environment, and then wear is accelerated with heavy and regular use.
Filters should be inspected and changed on a regular basis. In dusty situations, it may be necessary to use an air cleaner suitable for higher dust areas. Engine and drive manufacturers provide guidance on recommended service intervals that should be followed and adjusted based on actual operating conditions.
And lastly, one of the unspoken maintenance items is to watch for signs of abuse, misuse, or mishandling. As pumps are moved around a site, they can bounce and get bumped. Sometimes an unfamiliar operator or mechanic can create more problems than they fix.
So, what’s the next step?
It is important to know the equipment, the process, and the tools with which you are working. Identify the limits and the conditions around you. Have manuals and training materials available for reference. Establish procedures that are consistent and repeatable. Talk with co-workers, and share tips and tricks for maintenance. Use gauges and meters on the pumps and piping to compare to the specified or target values, as well as comparative information.
One of the hardest parts for most of us as engineers, mechanics, and all-around tinkerers is to keep up with maintenance, and then also think we can fix it if it does break. Be prepared to make the tough call and evaluate the repair versus replace situation on equipment. At a certain point, the equipment will start to increase in cost beyond what it becomes worth to use.
So, to make sure that we are not stuck without the battery, we need to look and know the equipment we use, make sure it is right for us, and then steadily maintain it. Kurt Vonnegut said, “Another flaw of the human character is that everybody wants to build, and nobody wants to do maintenance.” But in real life, if we don’t do the maintenance, we can’t build. After all, if our battery is dead, the car won’t go.
10 Keys to Pump Maintenance
1. Know the application.
2. Pick the right equipment.
3. Daily inspection and maintenance — look and listen to what is happening.
4. Watch abrasive and corrosive factors.
5. Check fluids and leaks.
6. Maintain wear parts.
8. Perform proper weekly checks on engines and drives.
9. Watch for abuse or misuse.
0. Monitor performance.
Thomas Aldridge is a sales engineer with Griffin Pump & Equipment Inc.