Flanged gate valve with soft sealing - series 20.900 - DN 250; L=250mm BRA.20.900

Product detailed description

Flanged gate valves are essential components in industrial and commercial HVAC systems, water distribution networks, and wastewater management. Installers and technicians commonly use these valves to isolate sections of pipe for maintenance, repairs, or system adjustments. In building services engineering, they are frequently found in heating circuits, chilled water loops, and domestic hot and cold water systems. Their robust construction and reliable sealing make them ideal for applications where frequent manual operation is not required.

Correct selection and installation of flanged gate valves depend on accurate assessment of system parameters such as nominal diameter, pressure ratings, and operating conditions. These valves are typically integrated into larger piping systems using standard flange connections and require careful alignment during installation to ensure leak-free performance. Their design allows for full flow when open and complete shut-off when closed, making them suitable for control and isolation tasks in a variety of fluid handling applications.

Technical parameters

Installation and connection

Installation begins with verifying the flange dimensions and bolt hole patterns to ensure compatibility with the adjacent piping. The valve should be installed in a straight section of pipe with sufficient clearance for bolting and alignment. Flange faces must be clean and free from debris before tightening bolts evenly in a crisscross pattern to prevent uneven stress on the gasket. Common installation mistakes include over-tightening bolts, misalignment between flanges, and failing to check for proper seating of the sealing elements. A visual inspection and pressure test after installation confirm correct assembly and function.

Compatibility and accessories

This valve is compatible with standard PN 16 flanged piping systems. It requires a suitable gasket, typically made of EPDM or NBR, to ensure a tight seal between the flanges. Additional components such as bolts, nuts, and washers should be selected based on the system’s operating conditions and the materials of the connected piping. No specific accessories are required for this model, and no related products are recommended for simultaneous installation.

Technical background for designers

The operating principle of this gate valve involves a wedge-shaped disc that moves vertically to either fully open or fully close the flow path. The disc is guided by trunnions and sealed against the valve seat using an EPDM-coated wedge and four NBR O-rings. The body is made of ductile iron (GJS 500-7), which provides high strength and resistance to deformation under pressure. The stem is constructed from AISI 420 stainless steel, offering good corrosion resistance and mechanical strength. The choice of materials ensures long-term reliability in water-based systems but limits the valve’s suitability for steam or oily fluids due to potential degradation of the sealing elements.

Service and operation

Periodic inspection is recommended to ensure smooth operation and integrity of the sealing surfaces. Key checkpoints include verifying the absence of leaks around the flanges and checking for any signs of corrosion or wear on the stem and seating surfaces. No scheduled maintenance intervals are specified, and no lubrication is required for the stem or moving parts. If the valve becomes difficult to operate, disassembly and cleaning may be necessary to remove accumulated debris or deposits.

Frequently asked questions

Can this valve be used in steam systems?
No, the valve is not suitable for steam applications due to the use of EPDM and NBR sealing materials, which degrade under high-temperature steam conditions.

What is the maximum operating temperature for this model?
The valve is rated for continuous operation up to +85°C, beyond which the sealing materials may begin to deteriorate.

Can the valve be used in wastewater systems?
Yes, the valve is suitable for wastewater applications provided the system operates within the specified temperature range and does not contain substances that could chemically attack the sealing materials.