Vibration Standards for Screw Compressors

Introduction: The Core Significance of Vibration Monitoring

As a core power‑driving device in industry, the operational stability of screw compressors directly determines production safety and energy efficiency. Vibration is the most intuitive indicator for assessing mechanical health; excessive vibration not only accelerates wear on bearings, gears, and seals but can also lead to structural fatigue, pipeline rupture, and even unplanned shutdowns. Establishing a scientifically sound vibration‑control system is essential for ensuring the long‑term, reliable operation of such equipment.

Core Measurement Parameters and Standard Test Locations

Vibration assessment primarily relies on three physical quantities: displacement, velocity, and acceleration. For medium- to high-speed rotating machinery,Root mean square vibration velocity (mm /s)It is currently the most widely adopted quantitative parameter in the engineering field. Standard test points typically cover the following areas:

• Horizontal, vertical, and axial positions of the bearing housings on both the drive side and the non-drive side of the host machine.
• Motor support frame and base mounting node
• Near the connection flange between the oil–gas separator and the cooler

When collecting data, avoid the resonance zones of external piping, ensure that the measurement point surfaces are smoothly ground, and use a dedicated magnetic holder or adhesive probe to guarantee tight coupling.

Industry-Wide Reference Thresholds for Evaluation

International standards for evaluating vibration in rotating machinery often use multiple reference points.ISO 10816Series of standards. This system classifies different alarm levels based on equipment quality, foundation stiffness, and rated rotational speed. Under normal operating conditions, the root-mean-square value of vibration velocity for a unit in excellent condition should be kept within4.5 mm within /s; The operating section falls within 4.5 至 7.1 mm A value of /s is within the acceptable range, but the inspection interval should be shortened and trends recorded; if the value exceeds the limit… 7.1 mm The /s indicator signals a potential fault, and a shutdown for maintenance should be scheduled. Note that the specific limit values must strictly adhere to the equipment manufacturer’s technical manual, as variations in discharge pressure, cooling method, and installation configuration can lead to changes in the actual tolerance limits.

Analysis of Typical Causes of Excessive Vibration

Abnormal vibrations are often caused by the combined effects of multiple factors; during troubleshooting, it is essential to distinguish between mechanical‑structural and fluid‑dynamic sources.

• Rotor dynamic balancing failure: Long-term carbon buildup or component shedding disrupts the mass distribution, generating high-frequency centrifugal forces.
• Poor shaft alignment: Coupling installation misalignment or insufficient thermal expansion compensation results in periodic impact loads.
• Bearing clearance exceeds the specification.: Nonlinear vibration response induced by inadequate lubrication or fatigue spalling
• Fluid Pulsation and Surge: Damage to the intake valve disc, fluctuations in pipeline backpressure, or operating conditions deviating from the design point can trigger strong low-frequency vibrations.

Preventive Maintenance and Long-Term Management Mechanisms

Reliable vibration management hinges on systematic operation and maintenance procedures. It is recommended to deploy online monitoring terminals to capture real-time changes in spectral characteristics, enabling early warning. Routine maintenance should prioritize the following key steps:

• Regularly inspect and tighten the foundation anchor bolts, and replace aged or failed rubber vibration isolation pads.
• Maintain the cleanliness of the lubrication system’s oil by measuring its viscosity and water content in accordance with the prescribed procedures.
• Use a laser alignment instrument to calibrate the drive shaft system, thereby eliminating assembly‑induced cumulative errors.
• Establish a vibration logbook and compare it with historical baseline data to identify progressive degradation trends.

When monitoring values continue to rise or are accompanied by unusual noises or abnormal temperature increases, the load‑reduction procedure should be initiated immediately, and a specialized agency should be engaged to perform shaft alignment or component replacement. Systematic data tracking and targeted maintenance can significantly reduce unplanned downtime and extend the overall service life of the equipment.