Vibration Standards for Screw Air Compressors

The core reference basis for vibration standards

Vibration assessment for screw air compressors does not rely on a single numerical value; rather, it requires a comprehensive evaluation that takes into account the equipment’s type, power rating, and rotational speed. In practical industrial applications, the primary references are the vibration‑evaluation standards for rotating machinery issued by the International Organization for Standardization, as well as the corresponding national standards. These standards typically categorize machinery into distinct power and speed ranges and establish corresponding vibration‑intensity assessment zones, ranging from “good” to “permissible,” with allowances for short‑term operation, up to the “machine damage” level.

Key Locations and Parameters for Vibration Measurement

Accurately acquiring vibration data is a prerequisite for assessing compliance with standards. Measurement locations are typically selected on bearing housings, machine casings, or structurally rigid components to faithfully reflect the vibration conditions of the rotor and bearings. With regard to evaluation parameters,Root mean square vibration velocityIt is the most commonly used indicator for quantifying mid-frequency vibration energy and assessing the overall vibration intensity of a machine. For high-frequency impact vibrations, it may be necessary to refer to vibration acceleration parameters. During measurement, ensure that the sensor is securely mounted to avoid introducing additional measurement errors.

Common factors causing abnormal vibration

When the vibration levels of a screw air compressor exceed the permissible limits, they are typically caused by the following mechanical or installation issues:

• Rotor imbalance: The rotor of the host machine or the motor rotor exhibits uneven mass distribution due to wear, scaling, or manufacturing tolerances.
• Poor alignmentThe coupling between the motor and the main machine is not aligned with sufficient precision, resulting in additional bending moments during operation.
• Bearing wear: Excessive clearance or damage to the support bearings causes instability in the rotor’s operating trajectory.
• Foundation and Fastening Issues: Loosening of anchor bolts, insufficient foundation stiffness, or cracking of the grouting layer can trigger overall resonance.
• Pipeline stress: External connecting pipelines impose additional tensile stresses on the housing, leading to body deformation and increased vibration.

Vibration Control and Routine Maintenance Strategies

To keep the vibration of screw air compressors within specified limits, companies should establish a comprehensive equipment‑condition monitoring system. After installation, new equipment should undergo an initial vibration test and have baseline data recorded as a reference for future comparisons. During routine operation, data should be collected regularly using portable vibration analyzers or online monitoring systems. If vibration levels show an upward trend or approach the standard alarm thresholds, the equipment should be promptly shut down for inspection to identify potential issues in the rotor, bearings, and connecting components, thereby preventing continued operation under fault conditions that could lead to more serious mechanical failures.