Overview

The WFB vertical self-priming pump is a centrifugal pump designed for "vertical" installation and equipped with a "self-priming" function. As the name suggests, "vertical" means the motor is positioned at the top while the pump head sits below, allowing for a straightforward, upright mounting configuration. Meanwhile, "self-priming" indicates that the pump can automatically draw liquid from positions lower than its inlet—eliminating the need to manually fill the suction line and pump chamber with liquid (i.e., no "priming" required)—before starting operation.

Key Features and Operating Principle

Self-priming principle:

This is its most essential feature. The pump body is designed with a gas-liquid separation chamber (fluid storage cavity).

Before the first startup, a certain amount of "priming fluid" needs to be injected into the pump chamber (which will then be stored in the reservoir).

After startup, the impeller spins at high speed, violently mixing the liquid with the air in the suction line to form a gas-liquid mixture.

The mixture enters the expanded gas-liquid separation chamber, where the reduced flow velocity allows the denser liquid to sink under gravity and return to the impeller via a reflux port, continuing its role in the mixing process.

Lighter air is continuously separated upward and expelled from the pump body.

This process repeats continuously until all the air is expelled from the suction line, creating a vacuum that allows liquid to be drawn up under atmospheric pressure, completing the self-priming cycle. Afterward, the pump transitions into its normal liquid-transfer mode.

Vertical structure:

The motor is arranged perpendicular to the pump shaft, resulting in a compact structure that occupies minimal floor space.

The bearings and motor are located at the top, away from the liquid, eliminating the risk of submersion and ensuring a better operating environment.

Clog-free impeller design:

For wastewater applications, WFB pumps typically use open or semi-open impellers, or single- or dual-flow impellers with wide flow passages that can easily handle solid particles and fibrous materials of a certain size, offering excellent anti-clogging performance.

Mechanical Seal:

High-performance mechanical seals are typically used, ensuring reliable sealing during pump operation and minimizing leakage.

Core structure

Vertical single-stage, single-suction design

Pump body: Designed for vertical installation, it occupies minimal space, making it ideal for areas with limited room—such as floor-level equipment rooms or mobile pump trucks.
Impeller: Semi-open or closed design, with blades featuring either backward-curved or radial profiles, balancing self-priming performance with efficiency.
Gas-liquid mixing chamber: Located at the top of the pump body, it features a specially designed flow channel that ensures thorough gas-liquid mixing, thereby reducing the self-priming height.

Self-priming device

Liquid storage chamber: A liquid storage chamber is located at the bottom of the pump body. Before the first startup, it must be filled with liquid; during subsequent operation, the self-priming capability is maintained via the siphon effect.
Return hole: A return hole is installed at the impeller outlet to allow some liquid to flow back into the suction pipe, enhancing gas-liquid mixing and reducing self-priming time.

Seals and Bearings

Mechanical Seals: Equipped with double-face mechanical seals or cartridge-style seals, offering excellent corrosion resistance and ensuring a leakage rate of ≤3 mL/h.
Bearings: The upper end features a rolling bearing (which supports radial forces), while the lower end has a sliding bearing (designed to handle axial forces), with a lifespan exceeding 20,000 hours.

Material Selection

Flow path components: Available in stainless steel (304/316L), fluoroplastics (PTFE/PVDF), fiberglass-reinforced plastic (FRP), and other materials, selected based on the corrosivity of the medium.
Structural components: The pump shaft is made of stainless steel or carbon steel with chrome plating, while the pump casing is crafted from cast iron or engineering plastic.

Performance advantages

Excellent self-priming performance

Self-priming height: Vertical suction lift can reach 5–8 meters (depending on the density and viscosity of the medium), while horizontal suction lift exceeds 50 meters.
Self-priming time: ≤90 seconds under clear water conditions (5-meter suction lift), and ≤180 seconds under thick slurry conditions (3-meter suction lift).
No priming required: After the initial fluid fill, subsequent startups don’t need manual priming—perfect for unattended operation scenarios.

Strong corrosion resistance

Material compatibility: Capable of handling media with pH values ranging from 1 to 14, including highly corrosive liquids such as concentrated sulfuric acid (up to 60%), hydrochloric acid (up to 35%), and sodium hydroxide (up to 50%).
Case: A chemical company used a WFB pump to convey 40% hydrofluoric acid, operating continuously for 12 months without corrosion or leakage—resulting in a pump lifespan three times longer than that of metal pumps.

High-efficiency and energy-saving design

Hydraulic Model Optimization: CFD simulations are used to optimize the flow passages, resulting in an efficiency improvement of 8%–12% compared to conventional self-priming pumps.
Energy-saving data: When pumping 50 m³/h of clear water with a head of 20 meters, the power consumption is only 7.5 kW—15% more energy-efficient than comparable products.

Seamless operation

Wide-channel design: The channel width is ≥30mm, allowing smooth passage of impurities like fibers and particles, thereby reducing the risk of clogging.
Case: A wastewater treatment plant used a WFB pump to convey sludge with a solids content of 5%, at a flow rate of 30 m³/h, and operated continuously for 6 months without any blockages.

Stable and reliable operation

Low-vibration design: Axial force-balanced structure minimizes vibration, with noise levels ≤75 dB (measured at 1 meter).
Intelligent Protection: Optional overheat, overload, and phase-loss protection devices are available to prevent motor burnout.

Industry Applications

Suitable for industries such as steel and metallurgy	Suitable for industries such as oil	Suitable for industries such as power and others
Suitable for industries such as environmental protection	Suitable for municipal engineering, etc.	Suitable for industries such as construction