centrifugal pump set failure modes and causes|pump tripping problem

In this edition of the Centrifugal Pump Minute, James Farley, Senior Director of Product Management for Griswold, takes a look at the different types of centrifugal pump impellers. Additionally, James discusses how the .

Centrifugal pump sets are essential components in various industries, playing a crucial role in fluid transportation and circulation processes. However, like any mechanical equipment, centrifugal pump sets are susceptible to failure due to various reasons. Understanding the common failure modes and causes can help in preventive maintenance, improving reliability, and minimizing downtime. This document summarizes the typical failure modes and causes for centrifugal pump sets, covering potential issues related to the magnetic field, motor rotor, shaft coupling, pump shaft, impeller, pump set as a whole, liquid flow, and more.

Centrifugal pumps, which are a common pump used in industry, are known to fail as a result of problems that arise within the fluid, such as cavitation, and mechanical faults, such as found in bearings and seals. Vibration monitoring has been found to be suitable in determining faults

Centrifugal Pump Problems

Centrifugal pumps can experience a range of problems that can lead to failure if not addressed promptly. Some common centrifugal pump problems include:

1. **Cavitation**: Cavitation occurs when the liquid pressure drops below the vapor pressure, leading to the formation of vapor bubbles. These bubbles can collapse violently, causing damage to the pump components.

2. **Vibration**: Excessive vibration can indicate misalignment, unbalanced components, or worn bearings, which can result in premature failure of the pump.

3. **Overheating**: Overheating of the pump can be caused by factors such as high operating temperatures, inadequate cooling, or insufficient lubrication, leading to damage to the pump components.

4. **Seal Leakage**: Seal leakage can result in the loss of fluid, reduced pump efficiency, and contamination of the surrounding environment.

Centrifugal Pump Failure Causes

The failure of centrifugal pump sets can be attributed to various root causes, including:

1. **Poor Maintenance**: Inadequate or irregular maintenance practices can lead to the accumulation of debris, corrosion, and wear on the pump components, ultimately causing failure.

2. **Incorrect Installation**: Improper installation, such as misalignment of components, incorrect coupling, or inadequate foundation support, can result in pump failure.

3. **Operating Conditions**: Operating the pump beyond its design limits, such as excessive flow rates, pressures, or temperatures, can cause premature wear and failure of the pump.

4. **Material Defects**: Defects in the materials used for manufacturing the pump components can lead to structural failures, such as cracks, fractures, or corrosion.

FMEA for Centrifugal Pump

Failure Mode and Effects Analysis (FMEA) is a systematic approach used to identify and prioritize potential failure modes of a system, such as a centrifugal pump. Conducting an FMEA for centrifugal pumps involves:

1. **Identifying Failure Modes**: Listing all possible ways in which the centrifugal pump can fail, considering factors such as design, operation, and maintenance.

2. **Assessing Severity**: Evaluating the potential consequences of each failure mode on the pump performance, safety, and operation.

3. **Determining Occurrence**: Estimating the likelihood of each failure mode occurring based on historical data, experience, and expert judgment.

4. **Analyzing Detection**: Assessing the effectiveness of current detection methods in identifying and mitigating the failure modes before they cause significant damage.

Pump Failure Report Example

A pump failure report typically includes the following information:

1. **Date and Time of Failure**: Recording the date and time when the pump failure occurred.

2. **Description of Failure**: Providing a detailed description of the symptoms, behavior, and impact of the pump failure.

3. **Root Cause Analysis**: Investigating and identifying the root cause of the pump failure, considering factors such as design, operation, and maintenance.

4. **Corrective Actions**: Outlining the steps taken to address the pump failure, including repairs, replacements, or modifications to prevent recurrence.

Pump Tripping Problem

Pump tripping is a common issue that can disrupt the operation of centrifugal pump sets. Some common causes of pump tripping include:

1. **Overload**: Operating the pump beyond its rated capacity can cause overheating, overcurrent, and tripping of the pump motor.

2. **Electrical Faults**: Short circuits, ground faults, or electrical surges can lead to sudden tripping of the pump motor.

3. **Mechanical Issues**: Mechanical problems such as bearing failures, misalignment, or coupling issues can result in pump tripping.

4. **Control System Malfunction**: Faulty sensors, controllers, or programming errors in the pump control system can trigger unnecessary tripping of the pump.

Centrifugal Pump Failure Modes

Centrifugal pump sets can fail in various modes, including:

1. **Mechanical Failure**: Mechanical failures, such as bearing wear, shaft misalignment, or impeller damage, can lead to pump failure.

2. **Hydraulic Failure**: Hydraulic issues, such as cavitation, recirculation, or excessive pressure, can impact the pump performance and efficiency.

3. **Electrical Failure**: Electrical faults, such as motor overheating, winding insulation breakdown, or power supply issues, can cause pump failure.

4. **Operational Failure**: Operational errors, such as incorrect startup procedures, inadequate monitoring, or improper maintenance, can result in pump failure.

Centrifugal Pump Fault Modes

The fault modes in centrifugal pump sets can be classified into different categories, including:

1. **Motor Rotor Faults**: Issues related to the pump motor rotor, such as winding faults, bearing wear, or overheating.

2. **Shaft Coupling Faults**: Problems with the shaft coupling, such as misalignment, coupling slippage, or fatigue failure.

3. **Pump Shaft Faults**: Failures of the pump shaft, such as bending, cracking, or corrosion.

The document summarizes common failure modes and causes for centrifugal pump sets. It outlines potential issues for the magnetic field, motor rotor, shaft coupling, pump shaft, impeller, pump set as a whole, liquid flow, impeller, …

The LNN type pump is a single stage, double suction, horizontal split volute type centrifugal pump designed for water works, drainage, general service and circulating applications. It can be used with motor, steam turbine and gasoline .

centrifugal pump set failure modes and causes|pump tripping problem