Swing check valves are best fit for horizontal pipeline installation. For small valve sizes, a vertical installation (up to 4 “) with upward flow only is still possible, but for heavier weights of discs chattering and high noise issues can occur, so far balanced discs are more indicated (tilting type) in vertical applications. Check anyway with ORION if the valve is suitable for the desired installed position.
The body is in carbon or stainless steel and is also available in many other CRA. It is carefully designed for total reliability, to keep the pressure drops to a minimum and simple maintenance. The basic dimensions, wall thickness, face to face and flanges, comply with the relevant BS, API and ASME standards. The body neck is cylindrical in order to host the pressure seal bonnet. The seat is welded in or threaded if required and an integral over-travel stop for the disc is incorporated. Two threaded bosses are provided for the location of the hinge pin, closed by threaded or welded plugs for absolute tightness in temperature. Valves are eventually provided with drain threaded or welded connection. The connection ends are typically butt-welding type for high temperature applications.
The cover is in forged or cast steel. It is cylindrical, generally machined from bar-stock material and accommodates a conical surface for body gasket seating at the lower peripheral edge. A locking flange with a set of bolts pulls the cover outward, against the gasket, giving a preload for initial sealing.
The disc is part of the trim and is in forged or cast steel. Opposite to the seating surface there is a threaded spigot for the connection to the hinge arm by a nut and cotter pin. The seating surface is ground and lapped.
It is basically supplied in graphite for best fit up to class 1500 and in AISI 316L stainless steel for 2500, carefully machined to provide a perfect tight seal. Upon request, AISI 316L can be installed on every pressure rating.
The hinge pin is part of the trim. It is machined from ground bar in stainless steel. The hinge pin is centred in the body with two threaded NPT plugs. The pin can be easily removed for valve maintenance. If welded plugs are required, a better tightness and safety is ensured, despite of accessibility. On larger valves, blind flanges or pressure seal blinds are provided as well.