The basic swing Check valve consists of a valve body, a cover, and a disk that is linked to a hinge. The above disk swings, moving away from the valve-seat. This movement allows the flow to move in the forward direction, and it moves back to valve-seat when upstream flow is stopped, to prevent backflow.

The disc in a swing type Check valve has no guides as it fully opens or closes. There are many disk and seat design available, in order to meet the requirements of different applications.

The swing check valve allows full, unobstructed flow and automatically closes as pressure decreases. These valves are fully closed when flow reaches zero, in order to prevent backflow.

Turbulence and pressure drop in the valve is very low.

Borrowing its characteristics from a Swing Type Non-Return Valve the Multidoor Swing Check Valve comes in sizes 700 MM & Above with Two halves of a spherical shell (Body) with a diaphragm in between, freely swinging doors (2-4 depending upon size) on robust trunnion pins, metal to metal seats and faces is all that make a multi-door check valve. With its inclined seat, large girth, suitable disposition of mass on doors, ensure the doors close, following deceleration of forward moving water column on pump trip, about the time the forward motion ceases or before that, makes this valve truly non-slam with Recoil characteristics. Valve has an integral foot and does not require anchoring.

The dual disc check valve is known as non-return valve or retainer less check valve. The valve allows the medium to flow in one direction only and to prevent flow of fluids to the opposite direction. The valve is working in an automatic system which contains an articulated mechanism.

It is much lighter in weight and smaller in size compared to a conventional swing check valve body design. This valve design is the result of attempts to provide an alternative in solving the problem associated with swing check valves. The valve contains two spring-loaded plates that are hinged on a central hinge pin.

Ball Type Check Valves is a non-return valve with a very simple and robust design. The heart of the valve is rubber coated ball. The hinge-pin-disc mechanism used in conventional check valves, which is the cause of most operation and maintenance issues such as pressure drop, imperfect sealing, leakage, clogging, etc., is eliminated. As the pump starts, the ball moves out totally from the flow path, giving a full bore with maximum flow discharge and minimum head losses. As the pump stops, the ball rolls back and seats perfectly on the rounded valves seat ensuring totally leak-proof sealing.

The tilting disk check valve is similar to the swing check valve. Like the swing check, the tilting disk type keeps fluid resistance and turbulence low because of its straight-through design. Tilting disk check valves can be installed in horizontal lines and vertical lines having upward flow.

Some designs simply fit between two flange faces and provide a compact, lightweight installation, particularly in larger diameter valves. The disk lifts off of the seat to open the valve. The airfoil design of the disk allows it to “float” on the flow. Disk stops built into the body position the disk for optimum flow characteristics. A large body cavity helps minimize flow restriction.

As flow decreases, the disk starts closing and seals before reverse flow occurs. Back-pressure against the disk moves it across the soft seal into the metal seat for tight shutoff without slamming. If the reverse flow pressure is insufficient to cause a tight seal, the valve may be fitted with an external lever and weight. These valves are available with a soft seal ring, metal seat seal, or a metal-to-metal seal. The latter is recommended for high temperature operation. The soft seal rings are replaceable, but the valve must be removed from the line to make the replacement.