GAZAR Swing Check Valve

Swing check valves, like all check valves, are used to prevent back flow in the line. The pressure of the fluid passing through a system opens the valve, while any reversal of flow will close the valve. The swing check valve functions by allowing flow forces to move the closure element, it is a hinged clapper which swings or rotates around a supporting shaft. GAZAR Swing Check valves are manufactured and modified to the latest edition of API Standard 600/ASME B16.34 and tested to API Standard 598.

Acting design

Swing Check Valves are normally operated by the flow, if the flow stops and backs up, the valve will then be closed by the back-pressure.

Body

The body is full ported and spherical in form. The design utilizes large radiuses which allow for the stresses, flow resistance and turbulence to be kept to a minimum. Bosses are provided for optional drains.

Body-cover Joint

Standard body-cover joints of our swing check valves are machined as follows:

• Pressure Class: 150, 300, 600, 900 over.
• Joint Design: Male-and-Female, Ring Type Joint
• Pressure Class 600 also available in Ring Type Joint.
• GAZAR can supply any style of gasket required by customer.

Hinge Assembly

The hinge arm pivots on the hinge pin which is located near the disc’s center of gravity. Body penetration for the hinge pin is sealed with a soft steel gasket and flanged plug. The hinge arm is designed to withstand the shock load of quick closing to insure a longer life and continued shut-off. The hinge arm also has an integral disc stop that provides a positive stop in the open position.

Disc

Each disc’s seating surface is precision ground and mated to the seat ring for insurance of a positive shut off. The disc is secured to the hinge arm with the disc nut and pinned to prevent disengagement during service. We can provide either integral or overlaid seat facings at customer’s request.

Seat Ring

Seat rings are designed to greatly reduce and/or prevent any turbulence and avoid damages due to corrosion. The seat rings are forged or rolled in one piece and then seal welded and overlaid, if required. After welding and all required heat treating, the seat ring faces are machined, thoroughly cleaned and inspected before leaving for assembly.

Bolts And Nuts

For normal service conditions, ASTM A194 Class 2H and ASTM A193 Grade B7 nuts and stud bolts are furnished. If specified for high temperature service conditions, ASTM A194 Class 4 and ASTM A193 Grade B16 nuts and stud bolts are furnished. Standard bolting furnished for our stainless steel valves consists of ASTM A194 Class 8 and ASTM A193 Grade B8 nuts and stud bolts. GAZAR can supply any bolting as requested by the customer.

End Connections

Our standard production covers valves with:

• Flange ends with Raised Face (RF), Flat Face (FF) or Ring Type Joint (RTJ) that conform to B16.5.
• Butt-welding ends (BW) that conform to B16.25.
• All face-to-face/end-to-end dimensions conform to B16.10.
• Other special end connections are supplied according to customer’s requirements.

Accessories/optional Designs

Counterweight features are available as an accessory. Piston, tilting disc or API6D designs are also available to meet the customers’ requirements. Drains and bypasses are available as specified by the customer.