Air release valve – Müller

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An air release valve is a device installed on pipelines to automatically release air from the systems during operation. When air accumulates inside the pipeline, it can form air bubbles or air pockets, which may reduce flow rate, cause pipe vibration, or lead to water hammer.
The air release valve helps remove air, maintain stable pressure, and protect pumps and equipment.
Construction:
– Valve body: Typically cast from durable materials such as cast iron (GG25, GGG40), stainless steel (304/316), or steel, ensuring stable operation in various environment.
– Valve cover
– Float: The most critical component, usually spherical, hollow, and lightweight (commonly made of stainless steel). It is responsible for opening and closing the discharge mechanism based on the liquid level inside the valve.
– Sealing plug: Made from specialized rubber materials (EPDM/NBR) to tightly seal the air outlet when the valve is filled with water.
– Air outlet: Located on the top of the valve cover, where excess air is discharged
– Sealing gasket: EPDM / NBR
– Connection: threaded (DN15–DN50) or flanged (DN50–DN300)
– Lever/actuating mechanism: Connects the float to the sealing plug, transmitting mechanical motion as the float moves up and down.
Technical specifications:
– Size: DN15 - DN300 (suitable for various pipeline scales)
– Working pressure: PN10, PN16, PN25
– Operating temperature: 0–80°C, up to 120°C (stainless steel)
– Body material: Cast iron GG25, ductile iron GGG40, stainless steel 304/316
– Float: stainless steel 304/316
– Gasket: EPDM, NBR
– Connection type:
+ Threaded connection: Commonly used for smaller sizes (DN15 - DN50)
+ Flanged connection: Used for larger pipeline systems (DN50 - DN300)
– Media: clean water, light wastewater, fire protection systems, transmission pipelines
Key Characteristics:
– Fully automatic operation: Requires no power supply or manual intervention, helping to save costs and effort.
– Automatic air release, no external power required
– Improves system efficiency: Removing air bubbles from the pipeline helps maximize flow rate and reduce friction.
– High durability: The cast iron body is coated with epoxy for corrosion resistance, allowing it to withstand harsh working environments.
– Reduces the risk of water hammer and pipe rupture
– Stable operation with minimal maintenance
– Available in double-function type, allowing both large and small air discharge in a single valve
– Ductile iron body with high strength, suitable for medium- to heavy-duty pipelines
Benefits:
– Efficient removes air
– Increases actual flow rate
– High durability, easy installation
– Reduces pipe vibration and pressure surges
– Good chemical corrosion resistance
– Anti-clogging and self-cleaning design
– High level of synchronization
Disadvantages:
– Hygiene requirements: If the medium is dirty water, debris may adhere to the float or sealing gasket. Periodic disassembly and cleaning are required to ensure the valve does not become clogged or stuck.
– Unable to release very low-pressure air in empty pipelines (requires a specialized type).
– Fluid limitations: Not suitable for viscous, sticky fluids or those containing large solid impurities, as they may clog the float mechanism.
Applications
– At water supply pumping stations: Installed at the highest points of the discharge pipelines.
– Pipeline transmission networks: Installed at sections with elevation changes, pipeline peaks, or sloped segments.
– Fire protection systems (PCCC): Installed on main pipelines and branch lines.
– Automatic irrigation systems and high-tech agriculture: Installed at the main water source or at sections of drip/sprinkler irrigation systems.
– Wastewater treatment systems: Installed on pipelines carrying treated wastewater (clean effluent outlets).