u horizontal slurry pump design

What Is The Best Type Of Non-Return Valve Used On Sewage Pump Stations?

Flap Valves

The flap valve (or swing check valve) is designed to swing in one direction. They simply have a flap which opens with the flow of the liquid being pumped, and then shuts as the liquid tries to return – typically sealing against a brass or rubber seat.

Ball Check Valves

The ball type check valve has a rubber ball inside which is pushed out of the way as the flow of the liquid hits the ball. This creates a full bore passage whilst the liquid is being pumped; once the flow is stopped, the ball falls back into position and seals any liquid to pass backwards.

What type of check valves are best?

When selecting the right non-return valve for your sewage station, it’s important to consider the key disadvantage of flap valves is that rags, wet wipes and fibrous items can catch onto the edges of it causing blockages, whereas in contrast the round ball option will not allow any debris to attach to it.

With this in mind,Dura Pump always recommends ball check non-return valves as the most efficient and most reliable valve for a sewage pump station.We’ve also proved this by replacing flap NRVs which were experiencing regular blockages with the ball check valves, resulting in fewer blockages and increased efficiency for our customers.

Why is an non return valve (NRV) in a pump setup crucial when dealing with sewage and wastewater applications?

AnNRV in a pumpsetup for sewage and wastewater is crucial to prevent backflow of effluent into the pump or wet well when the pump stops. This protects the pump from damage caused by reverse rotation and prevents contamination of upstream systems, maintaining sanitary conditions.

What specific challenges does a non-return valve for a borehole pump face when the borehole is extracting wastewater or sewage, and how is it addressed?

A non-return valve for a borehole pump extracting wastewater or sewage faces challenges from solids and debris that can cause fouling or blockages, preventing proper closure. These are addressed by using valves specifically designed for wastewater, often featuring full bore designs, robust construction, and sometimes weighted flapper mechanisms to ensure reliable sealing despite the presence of suspended solids.

Describe the primary function of a non-return valve for a borehole pump when it's part of a system pumping sewage.

The primary function of a non-return valve for a borehole pump in a sewage pumping system is to maintain the prime of the pump and prevent the pumped sewage from flowing back down the bore when the pump is turned off. This ensures that the pump doesn’t have to re-prime itself with sewage each time it starts, reducing wear and energy consumption, and preventing contamination of the bore.

How does the selection of an appropriate NRV in a pump system for municipal wastewater differ from a clean water application?

The selection of an appropriate NRV in a pump system for municipal wastewater differs significantly from clean water. Wastewater NRVs must be designed to handle corrosive liquids, abrasive solids, and potential clogging. They often feature robust, self-cleaning designs, materials resistant to chemical attack, and larger clearances to pass solids, whereas clean water NRVs can be more delicate and designed for efficiency with clear fluids.

What are the potential consequences if a non-return valve for a borehole pump fails in a wastewater disposal system?

If a non-return valve for a borehole pump fails in a wastewater disposal system, potential consequences include severe backflow of sewage into the borehole or pump, leading to pump damage from reverse rotation, loss of prime, increased energy consumption due to constant re-priming, and significant environmental contamination or health hazards from uncontrolled sewage discharge.