Check valve fig. 407A, double-disc, wafer-type - straight DN50PN16 407A050C54

Application and Operating Principle in Hydraulic Installations

The check valve Fig. 407A is a key element for the safety of water and heating installations, designed for wafer-style mounting between pipeline flanges. Its main function is to automatically prevent backflow, protecting equipment from damage caused by uncontrolled reverse flow of the medium. Thanks to its double-disc construction with an integrated spring, the valve reacts immediately to changes in flow direction, closing securely in both vertical and horizontal positions. The stainless steel spring not only ensures rapid return of the discs to the closed position but also eliminates the risk of water hammer (so-called "water hammer"), which could damage other system components.

This model is particularly useful in pump-powered circuits where unidirectional flow of water, glycol, or other neutral media must be ensured. The flow coefficient Kvs of 34 m³/h at DN50 allows for efficient operation in installations with medium to high flow rates without creating excessive hydraulic resistance. It is worth noting that the valve has no drain function and cannot be upgraded to an automatic version – it is a fully mechanical device that operates reliably without the need for actuators or external power sources.

Materials of Construction and Resistance to Operating Conditions

The key to the long service life of this valve is the careful selection of materials responsible for its chemical and thermal resistance. The body is made of gray cast iron EN GJL-250, additionally protected by an epoxy coating – this combination shields the body from corrosion on both the outside and inside, even under difficult environmental conditions. The most critical moving parts – the closing discs, spring, and pin – are made of stainless steel AISI 304 (1.4301). Thanks to this, the valve can handle media that would quickly destroy standard steel or brass components.

Seals made of EPDM rubber ensure tightness over a wide range of operating temperatures. The valve is suitable for installations where the medium temperature reaches a maximum of +100°C (with temporary peaks up to +110°C), making it a universal solution for both domestic hot water (DHW) systems and low-temperature and high-temperature heating installations. The maximum working pressure of PN16 (16 bar) allows for safe operation in most standard building and medium-level industrial installations.

Wafer Mounting and System Compatibility

Mounting the Fig. 407A valve is simple and fast thanks to its wafer (flange-to-flange) construction, which allows it to be placed directly between two pipeline flanges without the need for additional branches or dimensional reducers. Mounting dimensions comply with EN 558-49, series 49, ensuring full compatibility with standard PN10–PN40 flanges used in the HVAC and water/sewage industries. The total weight is approximately 1.5 kg, facilitating handling during installation work at DN50 (2 inch) diameter.

It is worth highlighting the functionality of the measurement ports present in this model – they allow connection of a pressure gauge or other diagnostic devices directly before or after the valve without the need to disassemble the entire element from the pipeline. This valve can also operate in conjunction with other check or control valves in complex hydraulic circuits, increasing the safety of the entire flow control system.

Key operational data for this model include the nominal diameter DN50 (2") and nominal pressure PN16 (16 bar), which, with a flow coefficient Kvs of 34 m³/h, define its application range in installations with moderate flow rates. The device operates stably at temperatures up to +100°C (with temporary peaks up to +110°C), and its body made of epoxy-coated gray cast iron and moving parts made of AISI 304 stainless steel ensure resistance to chemical and thermal corrosion. The flange connections comply withEN 1092. The total weight is approx. 1.5 kg, facilitating transport and on-site installation by construction teams.

Thanks to its simple double-disc construction and high-quality materials, the Fig. 407A valve constitutes a reliable barrier against reverse flows, minimizing the risk of pump and heat exchanger failures throughout the installation. It is a