Schematic diagram of the water-lubricated screw mechanism

Overview of the Core Principles of Water-Lubricated Screw Compressors

Water-lubricated screw technology is a compression‑equipment operating mode that replaces conventional lubricating oil with deionized water or specially treated water. In this system, water not only provides lubrication between friction pairs but also fills the clearance between the rotor and the casing to ensure gas sealing, while efficiently removing the heat generated during the compression process.

Compression Process and the Mechanism of Water Film Formation

The screw compressor typically consists of a pair of intermeshing male and female rotors. As the rotors rotate, the tooth‑groove volume gradually expands to complete the intake process; subsequently, the grooves seal off and connect with the discharge port, causing the volume to decrease and compress the gas. During this cycle, a small amount of high‑pressure water is injected into the working chamber through a dedicated nozzle:

• Lubrication and friction reduction: Water forms a continuous film on the rotor surface and along the gear mesh line, reducing the likelihood of direct metal-to-metal contact and minimizing wear.
• Dynamic sealing: The incompressibility of water fills the minute clearances between rotors and between the rotor and the housing, preventing high-pressure gas from leaking into low-pressure areas.
• Cooling and temperature control: Water absorbs the heat of compression, keeping the exhaust temperature within a safe range and preventing thermal deformation of the materials.

Analysis of the Water Circulation System and Schematic Diagram Paths

A complete water-lubrication system comprises four key stages: water injection, separation, filtration, and reinjection. In the schematic diagram, the fluid flow path typically follows the logic outlined below:

• Water injection stageThe water pump pressurizes and delivers the treated water to the host unit’s air inlet or the medium-pressure injection point, with flow rate automatically adjusted according to the load.
• Gas–water mixtureThe compressed wet hot gas enters the vapor–liquid separator, where centrifugal force and gravity are used to achieve preliminary separation.
• Purification and ReuseThe separated water is filtered through a filter element to remove impurities and trace dissolved substances, then cooled before being returned to the storage tank, completing the closed-loop cycle.

Technical Features and Application Areas

Compared with conventional lubrication schemes, water-lubrication technology demonstrates distinct engineering advantages under specific operating conditions:

• The exhaust gases contain no oil residues, meeting the stringent cleanliness requirements of industries such as food and pharmaceuticals, and electronics and semiconductors.
• Eliminates the need for complex oil‑line cleaning and waste‑oil disposal, making long-term operations and maintenance significantly simpler.
• It has specific control standards for influent water quality and must be used in conjunction with softening treatment or online monitoring equipment.

The operational logic depicted in this schematic is broadly applicable to scenarios such as air compression, biogas purification, and the conveyance of process gases in chemical engineering. In practical engineering applications, it is recommended to tailor the water‑injection locations and seal‑gap design to the specific properties of the working medium, thereby ensuring the system’s long‑term stable operation.