Standard Flap Valves

Be Free of Debris!
Be Free of Debris!

Flap Valves are put on the end of a flanged pipe to allow the flow of water out of the pipe, but prevent anything from flowing back in, such as sticks, leaves or other debris. Under direct pressure the valve will open, and it will close when the pressure from outfall fluid is relieved.

Standard Features

Flap Valve

1. Cast Iron Design.
As opposed to fabricated parts, our cast parts have less potential for failure over time.

2. Machined Bronze to Bronze Seat.
Our machined seat provides a strong, flat surface for the lid to close against. It can withstand even the harshest conditions.  The 30" to 36" flap valves employ resilient to bronze seating.

3. Two Part Epoxy Coating.
Our flap valves have a coating that gives lasting protection against corrosion.

4. Stainless Steel Hinge & Cotter Pins.
Our valve pins are made of stainless steel so they won’t corrode and bind up the valve.

5. Optional Resilient to Bronze Seating.
This allows for a softer reseating surface and can offer an improved seal.

Stainless Steel Flap Valves

SS StandardFlap Valve

Penn-Troy offers a 4” flap valve in 304 and 316 stainless steel and a 6” valve in 316 stainless steel. Each disc is supplied with a buna-n seal.

Operation

When properly installed, the flap valve will swing open under direct pressure to release the outfall fluid and close when the direct pressure is relieved. The Troy Valve A2540 Flap Valve has a 10-degree inclined seating plane to ensure positive seating.

Maintenance

Periodic inspection is recommended to determine that the flap disc remains free to swing open and that the bronze seats have not been damaged.

Installation

Valve must be installed so that the bolt holes in the flange (125-lb. template) straddle the vertical center line. See drawing for diameter and quantity required.

Parts

Parts are available by request. Please contact us for more information.

Application Notes

Head Loss Through a Flap Valve

Tests have been performed by Rodney Hunt Company in Massachusetts and other companies to determine the head loss through a flap valve. The tests showed that the head loss is small in comparison with other losses in the system. Tests were run with the flap disc removed from the valve and then with the flap disc in place. The difference in the head loss was therefore the result of the disc. The approximate maximum head loss obtained for the various sizes of flap valves is as shown in the following table:

SIZE OF FLAP (inches) MAXIMUM HEAD LOSS (feet)
6 .031
10 .04
12 .05
18 .076
24 .11

Flap Valve Sensitivity

Flap valves are normally very sensitive and open with a differential head of less than .2 ft.