Centrifugal Pump With Self Priming Device - China

Centrifugal pump with self priming device

The core principle of converting a conventional centrifugal pump into a self-priming pump is simply: It is to ensure the pump can retain water after shutdown and automatically expel air from the suction pipe upon startup.

The key to modification liesThe not in altering the impeller, but in installing two essential systems—the "water storage" and "gas-liquid separation" mechanisms—into the pump body.

1 - Maintain priming: For ordinary centrifugal pumps, water must be filled before each start-up as the water in the pump casing and suction pipe will drain out.

During modification, install a check valve(non-return valve) at the inlet to allow water to flow in but not out.

After shutdown, water can remain in the pump body and suction pipe, eliminating the need for refilling during the next startup

2 - Air Removal: Simply retaining water is not enough—there is still air in the suction pipe.

Self-priming pumps rely on an air-water separation chamber: the impeller mixes water and air into an air-water mixture and ejects it.

When the mixture enters a cavity with suddenly increased volume, the flow velocity drops sharply, causing the air to rise and be discharged through the outlet while the water falls back to continue the cycle.

After several repetitions, the air in the suction pipe is completely removed, and water rises

The core method for converting a centrifugal pump into a self-priming pump involves installing a foot valve or check valve in the suction pipe, along with improvements to the pump body sealing and priming system

Common modification methods

Install a foot valve or check valve: Install a foot valve at the bottom of the suction pipe or inlet to prevent water backflow and ensure the suction pipe remains fully filled with water.

Install an automatic suction device: Add a water collection pipe at the inlet and an air-water separator at the outlet to achieve automatic air venting.

Set up the water suction tank: Install a negative pressure water tank or filling chamber, ensuring sufficient liquid is retained for next startup

Key modification steps

Improve the shaft seal: Replace the cast iron bushing with a brass bushing and use a mechanical seal kit (static ring, dynamic ring, spring, etc.

) to ensure the sealing performance of the rotating shaft.

Pump Body Modification: Install a stationary ring sleeve and rubber gasket in the packing chamber, machine threads at the impeller shaft end to match the spring seat, and sequentially install the sealing kit.

Pipeline Connection: All components must be tightly sealed, with no air leakage in the suction and drainage pipelines

Precautions

Initial Water Filling: Before startup, fill the pump body with water, then close it after expelling air through the vent valve.

Sealing Inspection: Regularly check the wear condition of the pump body and impeller, and promptly replace worn components.

Installation Position: The pump should be installed as close as possible to the liquid source, with the inlet pipe kept as short as possible to minimize flow resistance

Company Contact:

• Posted By: Zhangjiagang free trade zone kenshine international trading Co.,LTD

• Phone: +8651258583352

• Address: Room 216-108, Textile resources market, Zhangjiagang , SUZHOU , China

• Email:

• Website: http://www.kenshine-pump.com

• Business Description: Our company is specialized in water pumps, electromechanical equipments and accessories etc for many years:
  
  …Various fluid pumps(centrifugal pump, chemical industrial pump, submersible pump, self priming pump, sewage pump, electromagnetic pump, diaphragm pump, gear pump, screw pump etc and their parts such as mechanical seal, pump casings, coupling, impellers etc)
  
  …Oil drilling equipments and parts (triplex mud pump, mud valve, drilling motor, drilling bits and parts of mud pumps such as piston, cylinder, valves and seats etc)
  
  …Mechanical parts and tools, instruments etc