18th Mar. 2026
What is a mid-opening pump (single suction impeller)
Centrifugal pump: The pump casing is horizontally split along the axial line (upper and lower halves). During maintenance, there is no need to dismantle the pipelines or motor, as the rotor can be directly removed by opening the cover.
Single suction impeller: The liquid enters the impeller center from **one side (one end)** and is accelerated by the blades before being thrown out.
Conventional single-stage mid-opening pumps are mostly equipped with double-suction impellers (water intake on both sides).
Single suction volute open impeller pump is commonly seen in:
A few special single-stage mid-opening pumps (single-side water intake)
Multi-stage medium opening pump (BB3): equipped with multiple single suction impellers arranged in a back-to-back configuration.
Working Principle of Single-Suction Impeller
Consistent with conventional centrifugal pumps:
The motor drives the pump shaft and single-suction impeller to rotate at high speed.
The liquid is axially drawn into the impeller center from one side.
The centrifugal force imparts kinetic energy and pressure energy to the liquid, flinging it toward the pump casing.
After deceleration through the volute and guide vanes, kinetic energy is converted into pressure energy and discharged from the outlet.
Multistage: The liquid sequentially enters the next stage of single-suction impellers for progressive pressurization, achieving high head.
Working principle of single suction impeller
Consistent with ordinary centrifugal pumps:
The motor drives the pump shaft and single suction impeller to rotate at high speed.
The liquid is sucked into the center of the impeller from one side axially.
Centrifugal force gives the liquid kinetic energy and pressure energy, and throws it towards the pump casing.
Through the deceleration of the snail shell/guide vanes, kinetic energy is converted into pressure energy and discharged from the outlet.
Multi stage: The liquid enters the next stage in sequence and is gradually pressurized by a single suction impeller to achieve high head.
Application scenario (pump opening in single suction impeller)
Mainly used in situations with high flow rate, medium to high head, stable requirements, and easy maintenance:
Urban water supply/plant
Water supply pump room and booster pump station of the water plant
Long distance water transmission and pipeline network pressurization
power industry
Thermal power plant: boiler feedwater pump (high-pressure multi-stage), circulating water pump
Nuclear power plant: important plant water and cooling water pumps
petrochemical
Refinery: crude oil transportation, oil product transfer
Chemical industry: process fluids, cooling water, boiler water
Mining/Metallurgy
Mine drainage, mine drainage
Steel mills and smelters: high-pressure circulating water
Water Conservancy/Municipal Administration
Flood control, drainage, and water diversion projects
Wastewater treatment plant: reclaimed water reuse, sludge water upgrading
Firefighting/Industrial
High pressure fire water system
Industrial cooling, cleaning, and spraying systems
