Bayard Norepol EA controllable anti-pollution check valve

The check valve protects drinking water networks against backflow of fluids, negative pressures in the network and back pressure from a network that may not carry drinking water.

Specifications:
- Body and bonnet in ductile iron GS/EN-GJS-450-10;
- Valve holder and seat in bronze/CuSn5Zn5Pb5;
- EPDM valve.
- Guide rod in stainless steel or bronze (depending on model).
- PETP anti-scale sleeve.
- Return spring and screws in stainless steel.
- PTFE pressure test tap.
- Nickel-plated alloy air vent.
- Horizontal or vertical upward mounting only.

Operation:
The valve is pushed by a spring, which creates a minimum pressure differential, greater than 0.10 mWC, in accordance with standard NF P 43-017. Thus in operation the downstream pressure remains lower than the upstream pressure, even at zero flow, which ensures excellent sealing. In the event of back pressure in the downstream network or accidental negative pressure in the upstream network, the pressure difference between upstream and downstream decreases, the shut-off mechanism closes and seals before the fluid reverses. This anticipatory closing effect gives this device an anti-pollution character.

Installation recommendations:
- The Norepol anti-pollution check valve is a sanitary safety device requiring an upstream isolation valve.
- A downstream isolation valve and a cleanable filter with drain are recommended to facilitate servicing and maintenance operations.
- The whole assembly must be placed in an accessible chamber.
- The clearance around the device must allow leak tests, repairs, fitting and removal to be carried out without difficulty.
- Before fitting the Norepol, clean the pipework by flushing it vigorously.
- Fitting a drain filter upstream of the Norepol is recommended; when used on loaded water, it is mandatory.

Complies with standards:
- NF P 43-017 and NF E 29-305-1 and ISO 5752.