Why Is Your Industrial Pump Failing?

Nothing is more frustrating for engineers and operation managers than pump failure. A failure can cause massive amounts of damage and cost you tens of thousands of dollars in clean-up and repair – not to mention the downtime and environmental hazard.

Often, pump repair skills are learned on the job. This hands-on learning has its time and place, but it can leave unfortunate gaps in pump knowledge, especially when it comes to diagnosing complex issues. This means that issues are often not noticed until the pump completely fails.

Learning how to recognize the symptoms of underlying problems in your pump can help you catch issues early – and fix them! Every symptom is related to an underlying cause and, therefore, has a solution. When you fix those issues, you can extend the life of your pump and improve your overall performance. You’ll also deepen your understanding of your own processes and systems.

Centrifugal Pump Basics

Today, we will be primarily addressing issues faced by centrifugal pumps, which are the most common type of pump found in the industrial sector. Traditionally, centrifugal pumps use an impeller which moves the fluid outward as it rotates. The movement of the impeller creates suction at the inlet, drawing material in.

Disk pumps are a unique form of centrifugal pumps. Instead of an impeller, they use parallel rotating disk packs to create momentum in the fluid and propel it through the system. Since the disk packs do not impact the fluid directly, it creates an unparalleled laminar flow.

Symptoms of Pump Failure and Their Causes and Solutions

Low NPSH-A

When your NPSH-A (Net Positive Suction Head – Available) drops below the NPSH-R (Net Positive Suction Head – Required), your pump won’t be able to function properly.

Potential Causes
This is often caused by a clogged suction line, low suction level, or negative static head. 
Solutions
Your immediate fix is to ensure your suction level is at the correct height and clear any clogs in your line.
If this happens repeatedly, you should ask the following questions:
-> Why is my material continually clogging?
-> Is my pump suited for the material it is moving?
-> Why is the suction level continually changing?
-> Is my pump’s NPSH-R too high?
Deadheading

Deadheading is when the discharge flow reduces to zero, i.e. a condition in which a centrifugal pump operates continually without any fluid flow through the pump. This condition causes pressure to increase inside the pump while churning. It can also cause the pump to violently vibrate and damage your bearings or blow your seal.

Potential Causes
There are a number of potential causes of deadheading, but primarily it is caused by clogging, thick or viscous material, or user error.
Solutions
This is a more complex issue because of the large number of potential causes. First, ensure that your pump is set up properly and that there has been no user error. For example, if the discharge valve is restricted too much, deadheading is a potential outcome.
If the pump is set up correctly, you should check for clogs next.
Once you are sure your lines and pump are free of clogs, it is time to evaluate the NSPH and your pump’s ability to handle the material you are pumping through it. Unfortunately, the only solution in this scenario is to redesign your system around a different pump or use a different material.
High Minimum Stable Continuous Flow

If you are operating below your minimum stable continuous flow, your pump will vibrate, potentially causing damage. When your pump’s minimum stable continuous flow is high and you are pumping viscous material, it can be hard to meet that flow rate, resulting in damage.

Potential Causes
Changes in your flow can be caused by pumping high pressure materials or substances like oil, which can change temperature. It can also be caused by maintenance such as flushing the line because of clogs.
Solutions
If your pump is vibrating and you cannot identify another reason, this could very well be the cause. Unfortunately, the only solution to this problem is using a pump with a minimum stable continuous flow that matches the material you are pumping. If you are pumping thick material, it not only requires a large amount of pressure to move, but generally it also will move more slowly.

Running Dry

When a pump runs dry, it means the pump is operating without an adequate amount of fluid. This can cause damage to many types of pumps within seconds. For example, pumps with most types of mechanical seals must maintain liquid against the seal face for lubrication. Running dry quickly destroys the seal.

Potential Causes
Running dry can be caused by many scenarios, including clogs of highly viscous materials, air in the line, or a hole in the line.
Solutions
First things first, check for a hole in your line that might be letting air in. Next, check for clogs. If there is a hole, patch it. If there is a clog, remove it.
If your pump is continuously running dry, you are most likely using a pump that cannot handle air, while pumping a viscous material that is prone to air pockets.

What Should You Do if Your Pump Is Continuously Failing?

If you are continuously experiencing pump failure, it might be time to consider if you are using the right tool for the job. Traditional centrifugal pumps are efficient and widely used for that reason, but when you introduce highly viscous or difficult to pump materials into the equation, they can cause problems.

That is where Discflo’s disc pumps come in.

Our disc pumps are specially designed for highly viscous materials, so our NPSH-R is one third of that of a traditional centrifugal pump and our minimum stable continuous flow is a fraction of what is currently available from traditional pumps. Because disc pumps are designed for highly viscous materials, our pumps can also handle up to 20% air, which minimizes running dry.

Moreover, our disc pumps generate pressure differently than traditional centrifugal pumps, as our disk packs never contact the product directly. This unique method for generating pressure minimizes deadheading, as the pressure does not build up within the product.

Our disc pumps are built to last years with minimal maintenance, making your life easier and decreasing your costs in the long run. In fact, our disc pumps often run as long as 20 years with little maintenance and no repairs.

So if you are pumping viscous materials or operating in difficult applications where traditional pumps are failing you, Discflo’s disc pumps are your long-term, cost effective solution.

Contact our sales team today to talk about how our pumps can improve your operation.

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