WFB Series Sealless Self-Priming Pump: Leak-Free Transfer Without a Foot Valve
The WFB Series Sealless Self-Controlled Self-Priming Pump eliminates mechanical and packing seals entirely, replacing them with a multi-face centrifugal dynamic sealing arrangement. This design prevents the common leakage problems — drips, spills, and seepage — that plague conventional pump installations across petrochemical, municipal, and industrial facilities.
How the Self-Priming Mechanism Works
At startup, the pump relies on a vacuum-principle design integrated with an electric air control valve at the suction inlet. When the pump stops, this valve opens instantly, allowing outside air to enter the suction line and break any siphon effect. The pump chamber retains enough liquid for the next start, achieving what the manufacturer describes as “prime once, self-prime permanently.” This electromechanical integration means operators do not need to manually refill the chamber after each shutdown cycle.
Key Design Features
Sealless Dynamic Sealing System
The centrifugal dynamic seal operates without physical contact during normal running, which reduces wear and extends service life compared to mechanically sealed equivalents. The seal geometry has been optimized to minimize energy loss while maintaining containment integrity.
Material Flexibility
Depending on the transferred medium, the pump body can be manufactured in cast steel or stainless steel grades, allowing adaptation to corrosive chemical streams, high-purity water, or abrasive slurries.
Vacuum-Assisted Restart
The electric air control valve coordinates with the pump’s internal geometry to ensure rapid re-priming. This is particularly valuable in batch-process operations where pumps cycle on and off frequently throughout a shift.
Technical Specifications
| Parameter | Value |
|---|---|
| Speed | 2960 r/min, 1480 r/min |
| Suction/Discharge Diameter | 50 mm – 400 mm |
| Rated Flow | 5.6 – 1600 m³/h |
| Rated Head | 10 m – 125 m |
| Self-Priming Height | 4 m – 6 m (at ambient temperature, pressurized) |
| Ambient Temperature | ≤ 40 °C |
| Medium Temperature | ≤ 50 °C |
Model Designation Guide
The model code follows a straightforward pattern: the leading number indicates inlet diameter in millimeters, “WFB” designates the sealless self-priming type, the next number is rated flow in m³/h, and the final number is rated head in meters. For example, 80WFB-50-32 means 80 mm inlet, 50 m³/h flow, 32 m head.
Installation and Commissioning Notes
- Initial priming: Fill the pump chamber through the “prime port” or body ball valve before first start. After priming, tighten the prime port cap or close the ball valve to prevent air ingress.
- Pipeline support: Do not rest suction or discharge pipe weight on the pump flanges. Use independent pipe supports.
- Rotation check: Verify shaft rotation matches the direction arrow (clockwise viewed from the motor side) using jog-mode startup.
- Vertical discharge section: Install 0.5–1 meter of vertical pipe at the discharge before any bend.
- Winter protection: For outdoor installations in cold climates, provide hot-water or steam tracing, or drain the pump chamber when idle.
- Concentrated sulfuric acid: Never use water as the priming medium when pumping concentrated sulfuric acid.
Operational Limits
Running with the discharge valve closed for extended periods can cause vibration and liquid vaporization. Flow should not be throttled using the suction-side valve, as this promotes cavitation. Continuous operation below 30% of design flow requires a bypass line, and operation above 120% of design flow risks cavitation and motor overload.
Typical Applications
The WFB series serves a broad range of sectors including petroleum refining, power generation, chemical processing, steel manufacturing, pharmaceutical production, electroplating, environmental protection, municipal water treatment, textile dyeing, mining, and general commercial building services. Industries that previously relied on long-shaft submerged pumps, submersible pumps, or conventional self-priming designs have adopted this sealless alternative to reduce maintenance downtime and eliminate seal-replacement costs.
Altitude and Temperature Correction
Published self-priming heights are based on standard atmospheric conditions at sea level with ambient-temperature water. When installed at higher elevations or handling warm liquids, the rated self-priming height must be corrected using the formula: [Hs] = Hs − Hh − Ht, where Hh accounts for the atmospheric pressure difference at altitude and Ht accounts for the vapor pressure difference at the actual medium temperature.
Why Choose Chaodun Pumps
Chaodun Pump manufactures the WFB series at its production facility in Shandong, China, with quality control procedures covering hydraulic performance testing, material verification, and assembly inspection. The sealless design philosophy reduces the total cost of ownership by eliminating seal failures — one of the most common causes of unscheduled pump downtime in chemical and industrial service.
FAQ
Does the WFB pump need a foot valve?
No. The self-priming design with electric air control valve eliminates the need for a foot valve on the suction line.
What is the maximum self-priming height?
Under standard conditions (sea level, ambient water temperature), the pump achieves 4–6 meters of self-priming height. This value requires correction for altitude and medium temperature.
Can it handle corrosive liquids?
Yes. The pump body is available in cast steel or stainless steel configurations, selected based on the chemical compatibility requirements of the transferred medium.
How long does the dynamic seal last?
Because the sealing arrangement operates without friction during normal running, service life typically exceeds that of comparable mechanically sealed pumps by a significant margin.
What happens if the pump sits idle in winter?
For outdoor cold-weather installations, provide steam or hot-water tracing, or drain the pump chamber through the drain port to prevent freeze damage.