Unexpected shutdowns of screw compressors can disrupt production and cause long-term damage to equipment. Motor overload, high-temperature alarms, and abnormal oil consumption are among the most frequent issues. This article analyzes these three common failures and provides data-driven optimization strategies to enhance operational efficiency and reduce maintenance costs.

1. Motor Overload: Causes and Solutions

Motor overload is one of the most prevalent screw compressor failures, characterized by current exceeding rated values, which may lead to motor burnout. The root cause lies in excessive resistance beyond the motor's design capacity. Below are the primary factors and corresponding solutions:

1.1 Filter Blockage

Causes: Severe clogging of air filters, oil filters, or oil-gas separators increases resistance in the intake and oil circuits, forcing the motor to work harder. Contaminants typically include dust, impurities, or degraded oil byproducts.

Data Analysis: Monitoring pressure differentials across filters helps assess blockage levels. Exceeding threshold values indicates the need for replacement or cleaning. Composition analysis of collected contaminants can further optimize filter selection and maintenance schedules.

Solutions:

• Scheduled Maintenance: Replace or clean filters per manufacturer guidelines, adjusting intervals based on environmental dust levels and oil quality.
• High-Quality Filters: Use filters with high precision and flow capacity to minimize clogging risks and extend service life.
• Differential Pressure Alarms: Install sensors to trigger alerts when thresholds are exceeded, prompting timely intervention.

1.2 Minimum Pressure Valve Failure

Causes: A faulty valve seal may fail to maintain minimum system pressure during startup, forcing the motor to overcome higher resistance.

Data Analysis: Pressure curve monitoring during startup reveals abnormal spikes, indicating potential valve leakage or sticking.

Solutions:

• Regular Inspection: Check valve seals and responsiveness periodically; replace or repair if defects are found.
• Quality Valves: Opt for durable, wear-resistant valves to improve reliability.
• Startup Optimization: Ensure unloading valves fully open before startup to reduce initial load.

1.3 Unloading or Intake Valve Malfunction

Causes: Faulty unloading valves may not release system pressure post-shutdown, while stuck intake valves can force the motor to start under load.

Data Analysis: Abnormal current spikes and rapid pressure rises during startup suggest valve issues.

Solutions:

• Routine Checks: Verify valve movement and sealing performance; clean or replace as needed.
• Valve Cleaning: Remove carbon deposits or debris to prevent obstruction.
• Control Program Adjustments: Ensure valves fully open/close during shutdown/startup sequences.

2. High Temperatures: Causes and Preventive Measures

Elevated temperatures degrade lubrication, accelerate wear, and may trigger shutdowns. Key causes and countermeasures include:

2.1 Oil Filter Blockage

Causes: Restricted oil flow due to clogged filters reduces cooling efficiency.

Data Analysis: Monitor pressure differentials and conduct periodic oil contamination tests.

Prevention:

• Timely Replacement: Follow manufacturer schedules, adjusting for oil quality and operating conditions.
• High-Performance Filters: Select filters with optimal flow and filtration.
• Oil Circuit Optimization: Minimize flow resistance through design improvements.

2.2 Thermostatic Valve Failure

Causes: Malfunctioning valves disrupt coolant flow regulation, leading to inadequate cooling.

Data Analysis: Temperature discrepancies across the valve indicate operational faults.

Prevention:

• Regular Testing: Inspect valve responsiveness and seals.
• Robust Valves: Choose corrosion- and heat-resistant models.
• Control Refinements: Fine-tune algorithms for precise coolant flow adjustment.

2.3 Cooler Contamination

Causes: Accumulated dust, oil, or scale reduces heat dissipation.

Data Analysis: Declining temperature differentials signal contamination.

Prevention:

• Systematic Cleaning: Remove internal and external deposits regularly.
• Ventilation Management: Prevent hot air recirculation around coolers.
• Design Enhancements: Improve cooling system efficiency to reduce thermal load.

3. Excessive Oil Consumption: Diagnosis and Control

High oil usage raises operational costs and risks lubrication failures. Primary causes include:

3.1 Return Line Blockage

Causes: Obstructed return lines prevent oil from cycling back to the compressor.

Data Analysis: Low return-line temperatures or visual inspections reveal blockages.

Control Methods:

• Line Cleaning: Clear carbon buildup and debris periodically.
• Premium Lubricants: Use oils resistant to carbon formation.
• Separator Optimization: Enhance oil-gas separation efficiency to minimize losses.

3.2 Oil-Gas Separator Failure

Causes: Damaged separators allow excessive oil to escape with compressed air.

Data Analysis: Oil content measurements in discharged air exceed thresholds.

Control Methods:

• Scheduled Replacement: Adhere to maintenance timelines based on operating hours.
• High-Efficiency Separators: Install advanced models with extended lifespans.
• Parameter Adjustments: Lower discharge temperatures to reduce oil vaporization.

3.3 Prolonged Low-Pressure Operation

Causes: Sustained low pressure reduces separator effectiveness, increasing oil carryover.

Data Analysis: Continuous suboptimal discharge pressure readings indicate issues.

Control Methods:

• Pressure Optimization: Adjust parameters to maintain recommended levels.
• Leak Detection: Identify and repair system leaks promptly.
• Demand Management: Avoid extended low-load operation through usage planning.

Implementing these data-driven maintenance strategies enables enterprises to optimize screw compressor performance, lower upkeep expenses, and prolong equipment service life.