What is an Air Vent Valve?

In this blog post, you’ll read:An air vent valve is very much popular as a safety device. It releases air into the water supply piping system to avoid air-related problems. The air vent valves have an automatic mechanical design and can control and maintain pressure without any help from an operator.
Table of Contents

Air Vent Valve Benefits

An air vent valve is very popular as a safety device. It releases air into the water supply piping system to avoid air-related problems. The air vent valves have an automatic mechanical design and can control and maintain pressure without any help from an operator. The air vent valves are made of brass. The internal apparatuses, such as the small levers and springs, are made of stainless steel. The area of air vent valve usage is relatively low temperatures. These valves’ highest pressure designed and dimensioned for is 10 bars.

Types of Air Vent Valves

  • Float type: This air vent valve releases air in the piping nonstop.
  • Float type quick ventilation: It dissipates a large quantity of air upon system startup and discharges accumulated air continuously.
  • Float-type vacuum breaker: This air vent valve takes in air to lessen vacuum conditions and releases accumulated air, if any.

The difference between air vent valves with and without a quick exhaust mechanism seems to be during the operation at low pressure up to 0.015 megapascals. The valve confirms a smooth initial water supply by exhausting a large amount of air from the piping at low pressure.

air vents
air vents

Purpose of Brass Air Vent Valve

  • To protect piping & sanitary materials from corrosion due to air (oxygen)
  • To protect against water flapping at the faucet due to the atmosphere.
  • To protect against noise caused by the entrance of air into cold/hot water supply systems, air conditioning systems, and other systems.
  • To smooth startup and steady operation of water supply and other systems/devices through air discharge during primary water conveyance.

Technical Specification & Product Description of Brass Air Vent Valve

Standard size1/2″, 3/4″, 1″
ThreadISO228, ISO7/1
Working Pressure1.6Mpa
Tested Pressure1.0Mpa By Gas
Working MediumGas, water
Working Temperature-20° C≤ T≤ 120° C
Technical Specification

The main parts of an Air Vent Valve:

  • Cap
  • O-ring
  • Closing Apparatus
  • Main body
  • Plug
  • Pin
  • Float 

Brass Air Vent Valve Materials

ComponentsMaterials made of
StrainerStainless Steel
BodyNickel Plated Brass
FloatPolyethylene resin
Disc AsslyBrass
Air Vent Valve Materials

Installation of Brass Air Vent valve

Perfect installation is complicated for the operation of air vent valves. These valves are designed to exile air from the piping system; they should be located where the air is most likely to collect. You should install them at system high points in the vertical position with the inlet down.

The air vent valves remove the air that gathers in heating and air conditioning systems. Due to the powerful presence of oxygen inside the piping, galvanic corrosion occurs. This corrosion effect can be reduced by using brass. Moreover, these valves permit the adjustment of the heating and cooling power. They avoid the creation of air pockets inside radiators and fan coil units. The air vent valves have to be installed in a vertical position only. These should be set on top of each system. It would be easily identified whether the air pockets are formed by checking distribution manifolds, riser pipes, etc. The airflow of these valves increases following the working pressure of a system. When the pressure rises to 6 bar, the airflow increases to a maximum. The presence of air in a heating system causes a fall in its efficiency.

How Does an Air Vent Valve Work?

When liquid is driven through the system initially, the primary air inside the piping is pushed into the air vent by the pressure of the flow. The float rests in the air vent’s lower part, allowing the valve to stay open and continuously discharge air.

After the primary air venting, liquid flows into the air vent. The float increases with the rising liquid and closes the valve.

The liquid level drops if air enters the vent while it is closed. As a result, the float lowers down & allows the valve to open and discharge air again.

Air in the pipeline comes from 3 initial sources:

  • The pipeline itself: Before starting, a pipeline isn’t theoretically empty. It’s always filled with air. The air must be exiled until the pipeline is filled with any fluid.
  • Fluid pumped: Water always holds 2% air by volume. Adhesives or other dense fluids can trap air in pockets; when the fluid moves through the system, air separates from that fluid.
  • Mechanical equipment: Air enters the system through pumps, packing, valves, and pipe joints.

When air is permitted to be stored in pumping systems, the risk of damage to mechanical equipment is high. Sometimes, efficiency will also be sacrificed. Applying air vent valves might be a good start if a pumping system faces pressure surges and lowered efficiency.

automatic air vent working specifications and sizes
automatic air vent working specifications and sizes

Application of a Brass Air Vent valve

Air vent valves, specifically brass ones, have become fundamental components in various systems where the regulation of air within the system is crucial. Their primary function is automatically releasing trapped air from the system while preventing unwanted fluid or air ingress. Here’s a deeper dive into the applications of a brass air vent valve:

Heating and Cooling Systems:

  • Radiators: Air can become trapped in radiators, affecting their efficiency. An air vent valve ensures that any accumulated air in a radiator is expelled, allowing hot water to fill the entire unit, thus maximizing its heating capability.
  • Underfloor Heating: In these systems, it’s essential to ensure there’s no air trapped within the pipes, as it can cause uneven heating. A brass air vent valve helps maintain consistent heating by releasing trapped air.

Water Distribution Systems:

  • Water Tanks: In large water storage units, trapped air can affect water outflow. The valve helps maintain a steady flow by releasing this air.
  • Pumps: Air accumulation in pumps can cause them to cavitate, reducing operational efficiency and potential damage. An air vent valve ensures that this doesn’t happen.

Industrial Applications:

  • Processing Plants: Maintaining an air-free environment in specific processes is essential, whether it’s a chemical plant or a food processing unit. Brass air vent valves help achieve this.
  • Hydraulic Systems: Air can alter the hydraulic pressure in machines. Installing an air vent valve helps maintain consistent pressure and prevents potential malfunctions.

Fire Protection Systems:

  • Sprinkler Systems: In fire sprinkler systems, trapped air can delay or alter the system’s response. Brass air vent valves ensure that the system reacts promptly when activated.

Boilers and Pressure Vessels:

  • Trapped air within boilers and pressure vessels can lead to inefficiencies and potential hazards. The brass air vent valve plays a crucial role in ensuring safety and optimal performance by venting out this unwanted air.

Solar Water Heating Systems:

  • Air pockets should be minimized for these systems to function at their best. The air vent valve ensures that air is expelled, allowing the solar-heated water to circulate effectively.

Benefits of Using Brass for Air Vent Valves:

Given its properties, brass is an ideal material for air vent valves. It offers corrosion resistance, ensuring longevity even when used in water-based systems. Its durability means it can withstand the pressures of most systems. Furthermore, brass’s natural antimicrobial properties reduce the chances of microbial growth within the valve.

The brass air vent valve is a small yet pivotal component across a multitude of systems. Its function goes beyond just releasing air; it ensures systems operate efficiently, safely, and effectively. Whether you’re looking to install a heating system at home or oversee a large-scale industrial operation, understanding the importance and application of a brass air vent valve is essential.

heating air vent applications
heating air vent applications

Precautions for Installing Brass Air Vent Valve

Before installing the air vent valve, you should carefully wash the inside of the piping to remove dirt & scale. The application position of the sealing agent or where to attach seal tape is much more critical at the connection time. When connecting the product to piping, we should pay attention to this. The valve shouldn’t be disassembled. You should prepare enough space for inspections, maintenance, and repairs. Installing the product under the roof or inside the wall is terrible. The vertical installation will provide you with the maximum feedback. This air vent valve should be fixed where air tends to accumulate. We can use a stop valve-like gate valve, ball valve, etc., for maintenance and inspections if needed. When the atmospheric temperature becomes low, you should drain water. Otherwise, water is not to be used for an extended period.

from Caleffi Hydronic Solutions

Advantages of using Brass Air Vent Valve

Air vent valves have garnered significant attention in various industries, and their relevance cannot be overstated. These devices, often overlooked in their simplicity, are cornerstones for the seamless operation of many systems. The value they bring comes from many advantages, some immediately apparent and others more subtle but no less crucial.

Firstly, the primary role of an air vent valve is to ensure that air, an unwelcome presence in most fluid systems, is systematically expelled. Trapped air is a known culprit in disrupting the flow, causing erratic system behavior, and even leading to complete blockages. By providing a reliable exit point for this air, the valve guarantees that fluid, be it water or another medium, moves unhindered. This isn’t merely a matter of ensuring flow but optimizing it. A system devoid of trapped air functions at its peak efficiency, pushing out maximum output for the energy consumed.

But there’s more to the air vent valve’s role than ensuring a smooth flow. Consider the damage potential of a phenomenon like a water hammer – that loud, damaging fluid-system clunk when water flow is suddenly halted. It’s not just disruptive; it can, over time, weaken system integrity, leading to leaks or even catastrophic failures. Here, the air vent valve plays its part. By facilitating the consistent removal of air, it acts as a buffer, mitigating the intensity of shock waves that result in water hammer.

The longevity of systems is another critical concern for operators. Corrosion, especially from the inside, is a silent destroyer. Trapped air pockets, especially in closed-loop systems, can accelerate corrosion rates. By venting out such pockets, air vent valves become indirect guardians of the system, warding off corrosion and ensuring the system’s longevity.

The financial implications cannot be ignored either. An efficient system, free of trapped air, ensures that pumps and related components don’t have to work harder than they should. This operational efficiency translates directly to energy savings and, by extension, financial savings. Over the long run, these savings can be substantial.

Air Vent Kit
Air Vent Kit

Accurate metering is a necessity in many industries. Erratic behavior due to trapped air can lead to inaccurate readings, impacting processes that rely on these readings. In such scenarios, the air vent valve extends beyond mere system health and touches upon the very quality of the output.

Operational noise is another concern addressed by these valves. Systems with trapped air are noisier. Beyond the simple nuisance factor, excessive noise can indicate a system struggling with inefficiencies. The role of the air vent valve in ensuring quieter operation is, thus, twofold – providing a better working environment and serving as a marker for system health.

In conclusion, the humble air vent valve, often overlooked in the grander system design scheme, is a linchpin for operational efficiency, system longevity, and financial prudence. Its advantages underscore the need for industries to recognize, adopt, and maintain these invaluable components.

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