YDK CAST IRON THREADED AIR RELEASE VALVE – MODEL: KAX(T)

In water supply and drainage, HVAC, fire protection, and industrial piping systems, the build-up of air pockets obstructs the flow, reduces pump efficiency, and creates a risk of hydraulic shock. To avoid these problems, the YDK cast iron threaded air release valve, Model KAX(T), is installed on piping systems. This is a simple float-operated valve that releases air automatically without letting the fluid escape.

With its convenient threaded connection, the valve can be installed quickly and removed easily for replacement.

Construction and material table of the YDK cast iron threaded air release valve KAX(T)

The YDK cast iron threaded air release valve, Model KAX(T), is made up of 10 main parts, ensuring the automatic open/close function that vents excess air to the outside.

Dimension table of the YDK cast iron threaded air release valve, Model KAX(T)

Operating principle of the YDK cast iron threaded air release valve

The YDK KAX(T) single float air release valve operates by a fully automatic mechanical mechanism. When the valve chamber contains no liquid, the float sits in its low position and the valve is open, allowing air to escape freely to the outside.

When liquid enters the valve chamber, the buoyant force (Archimedes’ principle) acting on the float makes it move to the upper position, where it contacts and presses against the valve seat, performing the sealing function and preventing the liquid from escaping.

The closing/opening process takes place continuously and automatically throughout the operating cycle, meeting the requirement of venting accumulated air from the piping system without losing any liquid.

Installation locations and operating notes for the cast iron threaded air release valve

Installation locations of air release valves in the system

The valve should be installed at the local high points of the piping system, where air tends to accumulate because of its density difference from the liquid. For pipelines with continuously changing elevation, multiple air release points should be provided, one for each local high point, rather than being limited to a single location.

In fire protection systems, common installation locations for air release valves are the tops of vertical risers and the area near the water supply inlet to the sprinkler system.

In domestic and industrial water supply systems, common installation locations for the YDK cast iron threaded air release valve are after the pumping station and on pipe sections that rise through the floors of a building.

Mandatory installation orientation requirement: The valve must be installed vertically, with the valve head pointing upward, so that the float mechanism works correctly according to the principles of gravity and buoyancy. Installing it tilted or horizontally will distort the float’s path of movement, causing the valve to lose its automatic open/close function.

Operating notes for the cast iron threaded air release valve

In addition to its standard function for cold and hot water, the YDK cast iron threaded air release valve, Model KAX(T), can also be used with oil having a specific gravity of 0.85 or higher. Therefore, when selecting the valve for oil applications, the specific gravity of the liquid must be determined accurately to ensure that the float’s buoyancy is sufficient to perform the sealing function.

The nominal working pressure of the valve is PN16, corresponding to a shell test pressure of 1.5 MPa and a seat test pressure of 1.1 MPa. Operating beyond the rated parameters for extended periods can shorten the service life of the EPDM rubber sealing components.

During installation, the hex bolts must be tightened using the symmetrical method (in a diagonal sequence), to ensure the force is distributed evenly across the entire flange face and to avoid flange misalignment that could cause leakage at the joint.

Periodic maintenance of the YDK cast iron threaded air release valve

Because the main operating mechanism relies on the movement of the float and the tightness of the rubber seat, these components must be inspected periodically to detect sediment build-up or material aging at an early stage.

The recommended inspection interval is once every 3 to 6 months, depending on the quality of the water source used in the system. For water sources with a high sediment content, the inspection interval should be shortened to avoid deposits reducing the sensitivity of the float and preventing the valve from closing completely.

The inspection normally covers: observing whether the float moves freely, assessing the elasticity of the valve seat, and checking the condition of the O-ring and sealing gaskets.

Safety note for maintenance: Before removing the cover for inspection or maintenance, isolate the relevant pipe section or reduce the pressure in that area to a safe level. This avoids the risk of liquid spraying out at high pressure when the cover is opened while the pipeline is under pressure.

If you need consultation or a special quotation for the YDK cast iron threaded air release valve KAX(T), please contact An Phu Thanh via Hotline/Zalo: 0946 729 913. Our experienced team is always ready to support you.