The intake valve (also known as the unloader) is one of the most critical components in any compressed‑air system. Its primary function is to precisely regulate the air entering the compressor airend, directly influencing operating pressure, energy efficiency, and overall system lifespan. Below are five of the world’s leading brands in the design and manufacturing of screw‑compressor intake valves:

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Atlas Copco – Sweden

A global pioneer in compressor technology and developer of some of the most precise air‑inlet control mechanisms.

Main Intake Valve Series:

• GA Series Intake Valve – Designed for oil‑injected GA compressors from GA 7 to GA 75.

• ZR/ZT Oil‑Free Valve Assembly – Purpose‑built for oil‑free models with electronic solenoid‑controlled actuation.

• XP/XC Valve Module – Equipped with an intelligent load/unload mechanism.

Key Feature: High‑precision sealing with a brass valve seat and smooth initial‑pressure control during startup (Soft Start Bypass).

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Ceccato (Italy)

An Italian brand with European assembly known for practical, user‑friendly designs in oil‑injected screw systems.

Main Series:

• CDX Series Intake Valve – Industrial‑grade design for 5–75 HP units.

• CFX Modular Inlet Valve – Developed for Ceccato’s new production lines, offering fast installation and easy servicing.

Key Feature: Serviceable components with FKM O‑rings and a hybrid pneumatic–electrical control system for enhanced pressure stability.

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ELGi (India)

One of Asia’s strongest compressor brands, offering a wide range of intake‑valve configurations.

Main Series:

• LD/EG Series Intake Valve – Compatible with EG Series airends (EG 11 to EG 75).

• VFD‑Compatible Valve Assembly – Designed for variable‑frequency drive systems to optimize energy consumption.

• O‑Ring Enhanced Unloader – New‑generation design with improved serviceability.

Special Feature: Continuous‑modulation air‑inlet control to minimize impact during load engagement

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 Fusheng (Taiwan)

A well‑known Asian manufacturer focusing on durable, cost‑efficient designs.

Main Series:

• SA Series Inlet Valve – Used in SA 22 to SA 110 screw compressors.

• VH Series Modular Valve – Built for heavy‑duty industrial applications and 24‑hour operation.

Key Advantage: Composite structure featuring a hardened aluminum piston and heat‑resistant stainless‑steel springs.

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Hitachi (Japan)

A Japanese manufacturer recognized for its highly engineered mechanical unloader systems.

Main Series:

• OSP Series Intake Valve – Tailored for two‑stage oil‑free compressors.

• HISCREW Series Inlet Control Valve – Equipped with a servo pilot valve for smooth inlet‑pressure regulation.

Engineering Highlight: High‑accuracy pressure‑response behavior, stable load/unload control, and up to 12% lower power consumption compared to the previous generation.