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Bermad Model C50 - Wastewater Combination Air Valve

BERMAD C50 is a high quality combination air valve for a variety of sewage and wastewater networks and operating conditions. It evacuates air during pipeline filling, allows efficient release of air and gas pockets from pressurized pipes, and enables large volume air intake in the event of network draining. With its advanced aerodynamic design and double orifice, this valve provides excellent protection against air and gas accumulation and vacuum formation with improved sealing under low pressure conditions


Features & Benefits

  • Straight flow body with large diameter automatic orifice – Higher than usual flow rates.
  • Aerodynamic, full-body kinetic shield – Prevents premature closing without disturbing air intake or discharge.
  • Dynamic Sealing – Prevents leakage under low pressure conditions (0.1 bar).
  • Elongated body design – Prevents solids from making contact with valve’s operating parts.
  • Compact, simple and reliable structure with fully corrosion-resistant parts – Lower maintenance and increased life span.
  • Two inlets – Enabling back flushing and drainage.
  • Factory approval and Quality Control – Performance and specification tested and measured with specialized test bench, including vacuum pressure conditions.

Typical Applications

  • Sewage and wastewater pumping stations – Air relief and vacuum prevention.
  • Sewage and wastewater pipelines – Protection against air and gas accumulation and vacuum formation at elevations, slope change points and at road / river crossings.
  • Municipal and industrial wastewater treatment plants – Protection against air and gas accumulation and vacuum formation.

Additional Features

  • Surge Protection (anti-slam) – Smoother operation, preventing damage to the valve and the system (C50-SP).
  • Inflow Prevention – Prevents intake of atmospheric air in cases where this could lead to damaged pumps, required re-priming, or disruption of siphons (C50-IP).
  • Drainage Valve.

Principles of Operation

Pipeline filling:

During the filling process of a pipeline, high air flow is forced out through the kinetic orifice of the air valve. Once water enters the valve’s chamber, the float buoyed upwards causes the kinetic orifice to close. The unique aerodynamic structure of the valve body and float ensures that the float cannot be closed before water reaches the valve.

Pressurized Operation:

During pressurized operation of the pipeline, air accumulates in the upper part of the air valve chamber, causing the float to gravitate downwards. This in turn causes the automatic orifice to open, releasing the accumulated air. Once the air is discharged, the water level and float rise, causing the automatic orifice to close.

Pipeline Draining:

When a pipeline is drained, a negative differential pressure is created causing atmospheric air to push the float down. The kinetic orifice stays open and air enters the valve chamber, preventing vacuum formation in the pipe.

Surge Protection (anti-slam):

The Surge Protection device is fitted to the air valve outlet. In the event of a pressure surge it partially closes the valve’s outlet. The approaching water column decelerates due to the resistance of the rising air pressure in the valve.

Inflow Prevention:

The inflow prevention mechanism is a Normally Closed check device fitted on the valve’s outlet and preventing flow of atmospheric air into the valve.

Valve Selection

  • Body Material – Glass-reinforced Nylon
  • Inlet sizes – DN50, DN80 (2”, 3”)
  • Connections:
    - Threaded Male & Female BSPT
    - Flange ISO PN16
  • Outlets – Sideways, downwards
  • Additional features:
    - Surge Protection (C50-SP)
    - Inflow Prevention (C50-IP)

Operational Data

  • Pressure rating: ISO PN10
  • Operating pressure range: 0.1 - 10 bar
  • Operating temperature: up to 60°C

Air Flow Performance Charts

Air Relief and Intake

(Pipeline Filling, Draining and Vacuum Conditions)

Air Release

(Pressurized Operation)

PDF Datasheets

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Engineering Data*

2D CAD Drawing

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Engineering Data*
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Product code

Bermad Model C50 - Wastewater Combination Air Valve

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