Attention points for the suction and discharge pipes of sewage self-priming pumps:

(1) The suction pipe of each sewage pump should be equipped with a separate suction pipe and strive to be as short as possible to improve hydraulic conditions, reduce head loss, and minimize the possibility of impurities blocking the pipeline.

The design flow rate of the suction pipe is generally 1.0-1.5m/s, with a minimum of 0.7m/s to prevent sedimentation inside the pipe. When the suction pipe is short, the flow velocity can be increased to 2.0~2.5m/s. To facilitate the removal of accumulated air in the suction pipe, the horizontal part of the suction pipe should be slightly raised along the direction of water flow, and the pipe slope can be 0.005. When the connection between the suction pipe and the water pump needs to gradually shrink, an eccentric head should be used. The inlet of the suction pipe should be equipped with a horn mouth, with a diameter of 1.3-1.5 times the diameter of the suction pipe. The horn mouth is installed in the sump of the water collection tank.

A valve should be installed on the suction pipe of a self-priming water pump for maintenance purposes. If the pump is not self priming, it should be started by using a vacuum pump or water injector to divert water, and it is not allowed to install a bottom valve on the suction pipe, as the bottom valve is prone to blockage in sewage, affecting the start of the pump and increasing head loss and power consumption.

(2) The outlet pipe of a sewage pump generally has a flow velocity of not less than 1.5m/s. When two or more water pumps share the same outlet pipe and only one pump is working, the flow velocity should not be less than 0.7m/s to avoid sedimentation in the pipe. When the outlet pipe of the pump is connected to the outlet main pipe (connecting pipe), it should not be connected from the bottom of the main pipe to avoid sedimentation in the outlet pipe of the pump when it stops running.

When two or more water pumps share the same outlet pipe, each pump's outlet pipe should be equipped with a valve, and a check valve should be installed between the valve and the water pump; If the water pump adopts a separate outlet pipe and is free flowing, generally no check valve is required. All valves should be installed in the horizontal section as much as possible to prevent dirt from settling on the valve disc.

The laying of pipelines in sewage pumping stations generally adopts exposed installation. The suction pipe is often installed on the ground, while the outlet pipe is often installed overhead due to the depth of the pump room, usually mounted on a bracket along the wall. The layout of pipelines shall not hinder traffic and maintenance work within the pump station. It is not allowed to install pipelines above electrical equipment, or to obstruct traffic, equipment lifting, and maintenance within the station. Attention should be paid to the suction and discharge pipes of the sewage pump at the passage. The distance between the suction and discharge pipes of the sewage pump and the bottom of the pipe should not be less than 2.0m, and the pipeline should be stable. For the convenience of installation and disassembly, the pipelines inside the pump station generally use flange interfaces. Corresponding anti-corrosion measures should be taken for pipelines and valves.