Skip to main content

Pump Shaft Breakage: Case Studies and Solutions

By NTS

Pump shaft breakage is a common issue that can cause costly downtime and repairs in various industries. In this article, we will explore several case studies of pump shaft breakage and the solutions implemented to prevent future failures.

Case Study 1: Chemical Processing Plant

A chemical processing plant experienced repeated pump shaft breakages in their cooling water pumps. Investigation revealed that the pumps were not properly aligned with the motor and had excessive vibration due to the misalignment. This caused the pump shaft to fatigue and break over time. The problem was resolved by realigning the pumps and installing vibration monitoring equipment to detect any future misalignment or excessive vibration.

Case Study 2: Wastewater Treatment Plant

A wastewater treatment plant had issues with pump shaft breakage in their sludge pumps. The pumps were designed with a straight shaft and lacked a flexible coupling, causing excessive stress and vibration on the pump shaft. The problem was resolved by redesigning the pumps with a flexible coupling and a shorter shaft to reduce stress and vibration.

Case Study 3: Paper Mill

A paper mill experienced repeated pump shaft breakages in their pulp pumps. Investigation revealed that the pumps were handling abrasive pulp that was causing excessive wear on the pump components, including the pump shaft. The problem was resolved by replacing the damaged pump shafts with a more wear-resistant material and installing a vortex breaker in the suction line to reduce the impact of the abrasive pulp on the pump components.

Case Study 4: Power Plant

A power plant had issues with pump shaft breakage in their boiler feedwater pumps. Investigation revealed that the pumps were not properly lubricated, causing excessive heat and stress on the pump shaft. The problem was resolved by improving the lubrication system and installing temperature and vibration monitoring equipment to detect any issues with the lubrication and performance of the pumps.

Case Study 5: Oil and Gas Industry

An oil and gas company had repeated pump shaft breakages in their saltwater disposal pumps. Investigation revealed that the pumps were operating at a high flow rate and were experiencing cavitation, causing damage to the pump impeller and eventually leading to pump shaft breakage. The problem was resolved by reducing the flow rate and installing a cavitation eliminator to prevent future damage to the pump components.

Case Study 6: Mining Industry

A mining company had issues with pump shaft breakage in their tailings pumps. Investigation revealed that the pumps were not properly installed and were experiencing excessive vibration due to misalignment. This caused the pump shaft to fatigue and break over time. The problem was resolved by realigning the pumps and installing vibration monitoring equipment to detect any future misalignment or excessive vibration.

Case Study 7: Food Processing Plant

A food processing plant experienced repeated pump shaft breakages in their hot water circulation pumps. Investigation revealed that the pumps were operating at a high temperature and were experiencing thermal expansion and contraction, causing stress on the pump shaft. The problem was resolved by installing a flexible coupling and a longer shaft to accommodate the thermal expansion and contraction.

Case Study 8: Pharmaceutical Industry

A pharmaceutical company had issues with pump shaft breakage in their product transfer pumps. Investigation revealed that the pumps were not properly lubricated and were operating at a high temperature, causing excessive stress on the pump shaft. The problem was resolved by improving the lubrication system and installing temperature and vibration monitoring equipment to detect any issues with the lubrication and performance of the pumps.

Case Study 9: Water Treatment Plant

A water treatment plant experienced repeated pump shaft breakages in their high-pressure booster pumps. Investigation revealed that the pumps were operating at a high pressure and were experiencing excessive vibration, causing fatigue and eventual breakage of the pump shaft. The problem was resolved by installing a vibration eliminator and reducing the pressure of the system.

Case Study 10: Chemical Manufacturing Plant

A chemical manufacturing plant had issues with pump shaft breakage in their reactor feed pumps. Investigation revealed that the pumps were not properly aligned with the motor and were experiencing excessive vibration, causing fatigue and eventual breakage of the pump shaft. The problem was resolved by realigning the pumps and installing vibration monitoring equipment to detect any future misalignment or excessive vibration.

In each of these cases, the pump shaft breakage was caused by different factors, ranging from misalignment and excessive vibration to wear and lack of lubrication. However, in each case, the problem was identified and resolved by implementing appropriate design changes, maintenance procedures, and monitoring equipment to prevent future pump shaft breakage.

To prevent pump shaft breakage, it is important to properly design, install, and maintain pump systems. This includes ensuring proper alignment, installing flexible couplings, monitoring vibration and temperature, and using appropriate materials for the pump components. Regular maintenance, including oil changes and inspections, can also help to detect any issues with the pump system and prevent pump shaft breakage.

In conclusion, pump shaft breakage can be a costly and disruptive problem in various industries. However, by identifying the root cause of the problem and implementing appropriate solutions, pump shaft breakage can be prevented, leading to improved reliability, reduced downtime, and cost savings for businesses.

Comments

Popular posts from this blog

John Crane's Type 28 Dry Gas Seals: How Does It Work?

How Does It Work? Highest Pressure Non-Contacting, Dry-Running Gas Seal Type 28 compressor dry-running gas seals have been the industry standard since the early 1980s for gas-handling turbomachinery. Supported by John Crane's patented design features, these seals are non-contacting in operation. During dynamic operation, the mating ring/seat and primary ring/face maintain a sealing gap of approximately 0.0002 in./5 microns, thereby eliminating wear. These seals eliminate seal oil contamination and reduce maintenance costs and downtime. John Crane's highly engineered Type 28 series gas seals incorporate patented spiral-groove technology, which provides the most efficient method for lifting and maintaining separation of seal faces during dynamic operation. Grooves on one side of the seal face direct gas inward toward a non-grooved portion of the face. The gas flowing across the face generates a pressure that maintains a minute gap between the faces, optimizing flui...

Why Pump Shafts Often Break at the Keyway Area

By NTS Pump shaft failure can lead to significant downtime and repair costs in industrial plants. One of the most common locations for pump shaft failure is at the keyway area. In this article, we will explore the reasons why pump shafts often break at the keyway and what can be done to prevent such failures. The keyway is a high-stress point (weakest point)  on the shaft, where a key is inserted to transmit torque between the shaft and the pump impeller or coupling. During operation, the keyway experiences cyclic loading that creates a bending moment in the shaft, which is concentrated in the keyway area. Over time, this cyclic loading can cause fatigue failure in the shaft material, leading to a fracture at the keyway. In addition to cyclic loading, other factors can contribute to shaft failure at the keyway. Improper keyway design or installation can lead to stress concentrations or inadequate clearance between the key and keyway . Misalignment or overloading can also cause ex...

Boiler Systems: Troubles in Operation and Their Causes

Definition of boiler systems Boiler system is a system that is used to heat water and to generate required steam or hot water. The boiler system is generally composed of the following units: (a) Feedwater treatment unit: demineralizer, etc. In case that the raw water is supplied from a river, a lake and so on, the raw water treatment units (clarifier, filter,etc.) are required.  (b) Feedwater line, (c) Deaerator, (d) Boiler including preheater, superheater and desuperheater, (e) Steam and condensate line, (f) Condensate treatment unit, (g) Wastewater treatment unit, (g) Chemical injection unit. Classification of boilers by their structures (1) Cylindrical boilers (pressure : below 20 kgf/cm 2 ) : (a) Vertical boilers, (b) Flue-tube boilers, (c) Fire-tube boilers, (d) Fire and flue-tube boilers. (2) Water-tube boilers : (a) Natural circulation boilers (pressure : low to high), (b) Forced circulation boilers (pressure : low to high), (c) Once-through boilers (pressure : above 75 kgf/...

FACTORS IMPACTING COMPRESSOR SURGE

BY AMIN ALMASI. Surge can be a major challenge for turbo compressors. Operation in the surge area will result in instability, exposing the machine to destructive stresses and forces, high vibration, and even serious damage. Surge during shutdown (trip) has been reported for many turbo-compressors. This is particularly possible if the machine operates at high head and low flow, immediately before the trip, when the operating point can move toward the surge line and even pass it during coast-down (when the turbo-compressor reduces flowrate). When a turbo-compressor experiences a serious alarm, an emergency shutdown is usually initiated. But an immediate shutdown could result in a surge. In this case, the surge happens shortly after the shutdown (trip) and at a high energy level. This could be a surge at a high head (operating point could pass the surge line at high head). In many cases, there are advantages to not removing the driving power from the turbocompressor (tripping) immediately...

WHAT IS THE ULTRASONIC IN-LINE INSPECTION (ILI) PIGGING?

In-line inspection (ILI) of pipelines has established itself as the most efficient tool for evaluating the condition of a pipeline and an indispensable part of pipeline integrity management. Historically, there have been two major technologies used in in-line inspection for corrosion, the magnetic flux leakage (MFL) and ultrasonics (UT), each having their distinct properties and fields of application.  Ultrasonic (UT) ILI has always provided unique quality of information about the pipelines, rendering highest accuracy and tightest measurement tolerances. In the 1990s ultrasonic tools for detection of cracks have become available. Ultrasonic measurement principle: ultrasonic transducer slides along the internal surface of the  pipe wall measuring distance to the wall and the wall thickness (top), yielding the stand-off and the wall  thickness (bottom two B-scans) Ultrasonic (UT) based In Line Inspection tools for all types of liquid filled pipelines. This includes Ultras...