swing check valve disassembly1-BODY

Available both in cast and forged steel, it has been designed to meet all the requirements of ASME, API and British Standards.

The body-bonnet connection is made by a pressure seal gasket. Its pre-stress condition is achieved by mean-sof bolts screwed to the bonnet flange. Ends are normally butt-welding although they can be also flanged on request.

All bodies are provided with integrally cast bosses, located and sized in accordance with ASME B16.34, which allow the provision of drain.


Usually constructed in the same materials as the body.


Supplied in forged stainless steel, hardfaced with Stellite-6 (2mm of min. thickness). Seat ring is renewable, normally welded to the body.

Sealing contact surface is lapped for a perfect tight seal.


The disc is normally constructed in forged stainless steel for diamters upto 8”, and in cast steel of the same material as the body for larger sizes. Contact face is overlayed with 2 mm minimum thickness of Stellite-6.

It is designed so that the valve can operate both in horizontal and vertical positions.


The pressure seal gasket is usually supplied of compressed graphite, bordered on the upper and lower edges with braided filaments of carbon fiber.

Gasket can also be made in stainless steel.

swing check valve parts25-HINGE (ARM)

The arm is constructed of the same material as the valve body. Designed to swing smoothly, is provided with an integral mechanical stop, suitably machined, which contacts the valve body when the valve is in fully open condition, and avoids the disc to create the first contact.


Constructed from a stainless steel forged bar, is normally designed for being assembled externally through the side/s of the valve body, although internal shaft designs are also available on request.

In the normal external shaft construction, one or two cover/s (19A), fitted to the body with 4 studs (28A) assure a perfect tightness. Seal between cover/s and body is achieved by using spiral wound gaskets (17A).

For some special applications, to avoid slamming effect, shock absorbers (dashpots) are installed in the valve, connected to the hinge pin through stuffing box/es.


Made of a single piece covering the upperpartofthepressuresealgasket. It is normally manufactured in the same material as the body.


It is made normally of the same material as the body, and constructed in four pieces, called segments. The segments are sized to minimize the gap between them.

The segmental ring supports all the forcers transmitted from the bonnet through the pressure seal gasket and the spacer ring. It is calculated to withstand all the force withoutcrac- king.


Designed sufficiently resistant to withstand the forces transmitted by the cover stud (28). The cover retainer is normally made of the same material as the body, but it can be constructed in any other material on request. It is machined to match exactly with the body, what guarantees a perfect alignment of the unit.