Its spherical form of large radius allows for the stresses, turbulence and resistance to flow to be kept to a minimum.
Body-Bonnet Joints of check valves are machined as follows:
On 150, 300 & 600 classes; male and female.
On 900 and 1500 classes: RTJ.
Seat ring are manufactured in two different ways, depending on the class and type of valves:
- ✔️ Screwed seat rings, bottom seated type lapped on both side.
They are dry assembled, with a controlled torque setting to the body.
- ✔️ Welded-in seat rings, designed in order to prevent any turbulence and avoid damages due to corrosion.
Both are forged or rolled in one piece, for all dimensions. They are heat treated to obtain the requested surface hardness, and are perfectly cleaned before assembling.
Insert Seat Rings
These rings are manufactured with teflon or viton inserts, depending on fluid and service conditions.
They provide an elastometer primary seal. combined with a fire sale metal to-metal secondary seal, for temperatures from – 100oC (-144oF) to 204.4oC (400oF).
Where maintenance is a potential problem the viton insert is in the form of a toroidal ring so that it can easily be removed.
Our Standard Production Covers Values with
Flanged ends (RF) that conforms to ASME B 16.5 and Face to Face dimensions that conforms to ASME B 16.10, with a raised face serrated finish or on request with any other finish.
Butt-welding ends (BW) with end to end dimensions that conform to ASME B 16.10.
Customer must specify the type of schedule required, or class of pipe, or diameter and bore.
Ring-joint flanged ends (RTJ) that conform to ASME B16.5, with end to end dimensions as per ASME 10.
Other special end connections are supplied to customers’ special requirements.
Outside lever and weight on request swing check valves can be furnished with an outside lever and weight. In balancing the disc the valve will open with a minimum of pressure.
When the disc is weighed the valve will be very sensitive to a reversal of flow.
Dashpot feature in case of intermittent use or in presence of thrusts, dashpot feature is highly recommended. In such instance the dashpot feature gradually causes the opening and closing of disc preventing therefore dangerous shocks.
Check valves with pneumatic safety control. This is in the form of a simple pneumatic piston. In normal conditions of use, it pushes up the lever, thereby moving a special cam that allows the disc to move. Should there be no air in the cylinder, the spring allows the lever, and hence the disc to descend, thereby assuring that it encloses before any inversion of flow.