What level of noise is considered normal for the indoor unit of a screw compressor?

The normal noise range for the indoor unit of a screw compressor

It is normal for screw compressors to generate a certain level of noise during operation. Typically, the normal operating noise level of indoor units in commercial or industrial screw compressors falls within approximately…70 to 85 decibelsHowever, this figure is not absolute; the specific acceptable noise level can vary depending on the unit’s cooling capacity, compressor specifications, motor power, and design and manufacturing processes.

In practical assessments, the most accurate reference is the documentation provided with the equipment upon shipment.Technical nameplate or product manualIf the measured noise level falls within the range specified in the manual and the sound is steady and uniform, it can be considered normal.

Main factors affecting the indoor unit noise of screw compressors

Understanding the sources of noise helps to better assess equipment condition. In screw compressors, internal noise is primarily generated by the following components:

• Mechanical noise:It originates from the meshing of the screw rotors, the operation of the bearings, and the rotation of the motor. This constitutes the baseline noise during equipment operation.
• Aerodynamic noise:Aerodynamic noise generated by the high-speed flow of refrigerant or gas within piping, as well as by throttling and exhaust processes.
• Electromagnetic noise:Vibration and noise generated by the drive motor under the action of an alternating magnetic field.
• Structural Vibration Noise:Noise generated when minute vibrations during equipment operation are transmitted to the enclosure or mounting base, triggering resonance.

How to determine whether noise is abnormal

Although screw compressors generate noise during operation, certain specific sound patterns may indicate potential equipment issues. If any of the following conditions occur, it suggests that the noise level may have exceeded the normal range:

• Sudden change in voice:The noise level suddenly increased significantly, without a corresponding noticeable rise in load.
• Abnormal noise detected:Hear distinct metallic scraping, piercing whistles, muffled knocking, or irregular banging.
• Accompanied by violent shaking:Visible abnormal vibrations are observed on the equipment enclosure or connecting pipelines.
• Periodic anomaly:The noise exhibits a distinct periodic pattern of increasing and decreasing amplitude, which may be attributable to loose internal components or inadequate lubrication.

Effective Measures for Reducing In-Cabinet Noise in Screw Compressors

To improve the working environment and extend equipment lifespan, the following measures can be implemented to control and manage noise:

• Proper Installation and Vibration Damping:Ensure that the equipment mounting base is level and stable, use approved vibration-isolating pads or springs, and eliminate vibration transmission paths.
• Regular maintenance and servicing:Replace the lubricating oil on schedule, clean the filters, inspect and tighten any loose internal components, and ensure proper lubrication of the rotor and bearings.
• Optimize airflow distribution:Ensure that the air inlets and outlets are unobstructed, and that all duct connections are tightly sealed to minimize aerodynamic noise caused by flow turbulence and pressure losses.
• Add soundproofing facilities:Install sound-absorbing materials or acoustic enclosures on server room walls or the exterior of equipment to effectively absorb and block noise transmission.