Metal flap system VALVE HD

Product overview
The ACO Q-Flap Valve is a robust, lightweight non-return valve designed to let water discharge freely while preventing backflow. Mounted to a wall or headwall, it is typically installed above the waterline at outfalls, where dependable one-way flow control is essential.

The gravity-operated flap opens quickly under outgoing flow and closes automatically as soon as the head of water changes, helping protect networks from tidal surges, rising rivers, and flood events. Its smooth, responsive action supports free-flow systems without trapping debris, reducing the risk of silt build-up and keeping pipework clear over time. With durable HDPE construction, ACO Q-Flap Valve delivers long-term performance in demanding drainage, wastewater, and coastal environments, with minimal maintenance required.

Features

• UV-stable for outdoor use: High UV protection supports long-term performance in exposed locations.
• Built for harsh environments: Manufactured from high-quality HDPE with SS316L components (Q-Flap HD only) for excellent corrosion and chemical resistance.
• Long service life: Engineered for a 50-year design life with minimal maintenance.
• Serviceable sealing: EPDM lip seal is easy to replace when required.

Benefits

• Lightweight and easy to handle: HDPE construction keeps weight low, making installation quicker and safer.
• Stops backflow automatically: The valve opens with outgoing flow and closes securely to prevent reverse flow and flooding.
• Clean, efficient operation: Fast opening helps prevent silt and dirt build-up in the pipe. The limited opening angle also ensures the flap cannot remain stuck open.

Options / Variants
ACO Q-Flap Valve HD

• Technical info: Wall mounted (other options available).
• Permanent meter water column: 1 Mwc (above opening).
• 72-hour meter water column: 5 Mwc (from invert level).
• Standard available sizes: DN 100-2000M.
• 50 Year design life.
• Welded hinge construction.
• Includes DN 400 stainless steel reinforcement.
• Custom made designs possible.

ACO Q-Flap Valve SD

• Technical info: Wall mounted (other options available).
• Permanent meter water column: 1 Mwc (above opening).
• 72-hour meter water column: 5 Mwc (from invert level).
• Standard available sizes: DN 100-500M.
• Faster install time: only four fixing points.
• Bolted construction.

Other mounting options

• Wall mounting with an angle of 10°.
• Flange connection.
• Spigot end for connecting with socket/coupling or to be inserted in existing pipe.
• Opening moments of the flap valve can be adjusted on request.

Technical specifications

• Model: Q-Flap Valve (HD and SD variants).
• Material: HDPE (body); SS316L components on Q-Flap HD where specified.
• Seal: Replaceable EPDM lip seal.
• Design life: 50 years (engineered).
• Operation: Gravity-operated flap for one-way flow; fast opening and automatic closing; limited opening angle to reduce risk of stuck-open condition.
• Mounting: Wall-mounted or headwall-mounted; multiple mounting options (angled mount, flange, spigot).
• Hinge/Construction: Welded hinge construction (HD); bolted construction (SD).
• Reinforcement: DN 400 stainless steel reinforcement included in HD variant.
• Standard sizes: HD listed as DN 100-2000M; SD listed as DN 100-500M.
• Performance heads: Permanent meter water column ~1 Mwc (above opening); 72-hour water column rating up to ~5 Mwc (from invert level) as indicated for variants.
• Installation: Lightweight design for easier handling and quicker installation; SD variant requires only four fixing points for faster install.
• Applications: Drainage, wastewater and coastal outfall protection; protection against tidal surges, rising rivers and flood events.