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What is an Axial Flow Pump? Horizontal Axial Flow Pump / Elbow Pump / Forced Circulation Evaporation Pump

Learn - Sep. 05, 2022

axial flow pump elbow pump forced circulaion pump

An Axial flow pump, is a high flow, low head big fluid equipment, also known as the Horizontal Axial Flow Pump, Elbow Pump, Forced Evaporation Circulation Pump, used to handle large flow and low head of clear liquid or containing crystallization medium, is agricultural drainage and irrigation, urban water supply and drainage, water transfer engineering, salt making, desalination project commonly used equipment. Strictly speaking, it is not a centrifugal pump, its shape is also different from the common chemical pump, it has a huge inlet and outlet, like a huge horn, the maximum diameter of the outlet can reach 1800mm, the impeller like a giant fan. We often see these giant pumps in salt production, water treatment centers, desalination, mirabilite, alkali production, etc.

Horizontal axial flow evaporation circulation pump, used for large capacity, low head working conditions, as a transport or forced circulation pump, this article introduces the caliber of 1000-1800mm (big diameter ) large evaporation circulation pump, model for ZW. With its heavy-duty construction and flexible design, these series pumps ensure maximum reliability and are perfectly suitable for all kinds of large capacity low head industrial processes.

■ Horizontal axial flow pump structure

The horizontal axial flow pump is composed of the pump and the transmission part. The pump is composed of impeller, pump casing, shaft, bearing box and other components.The structure of horizontal axial flow pump as below:

the structure of horizontal axial flow ump

1.  The impeller. Impeller for cantilever support, spherical hub, impeller blade can be adjusted, by adjusting the blade placed Angle, can achieve to broaden the range of pump performance parameters. The blade shape of horizontal axial flow pump is a three-dimensional twisted structure. By using the Clearance Flow Numerical Simulation Theory and based on the CFD platform, optimize hydraulics and promote propeller profile performance  ,provides high efficiency while reducing net positive suction head (NPSH). The impeller of axial flow pump is carried out unsteady numerical calculation of the whole flow field, and the theoretical 3D impeller model with the best hydraulic model is designed. The propeller is provided with a short tube, easy to adjust the clearance of the impeller outer edge.

2.  Pump casing. That is, the pump bady, the pump shell, which is a curved pipe flow channel design, is a very vivid Elbow Pump, the pump body is modular Mosaic welding. For special High Pressure conditions, the integral forging molding is adopted. Horizontal axial flow pump can be mounted by suspension, with advanced thermal compensation technology. The installation of ZW horizontal axial flow pump can be done without the base, and there is no expansion joint on the entire pipeline, which can save a lot of procurement costs for the end user. Horizontal axial flow pump is often used with evaporator, crystallizer, reactor, cantilever installation structure is conducive to coordination and unity with the evaporation system.

3.  The shaft seal. According to the working condition, choose packing seal, single mechanical seal, or double mechanical seal.

①Packing seal, efficient and simple, packing seal for inner and outer sealing, replacing packing, no need to stop operation, fast and convenient.


②Single mechanical seal, conforms to API682, flush Plan02 or Plan32 or Plan62. Choose the flushing water pressure according to the requirements of working conditions. The flow rate is usually 3-26L/min. Turn on the rinse water 5 minutes before starting the machine, and then turn it off 5 minutes after stopping the axial flow evaporation forced circulation pump.

③Double mechanical seal, conforms to API682, flush Plan54. The flushing water pressure is 1-2bar higher than the sealing chamber pressure, and the flow rate is usually 6-52L/min. Turn on the rinse water 5 minutes before starting the machine, and then turn it off 5 minutes after stopping the pump.

Mechanical seal can achieve leakage, no pollution to the environment, so that the service life of the horizontal axial flow pump is longer, to ensure the safety of the working environment, ECO-friendly. Most of the end users choose mechanical seal.

Last but not least, the packing seal and the mechanical seal can be interchanged with only a small number of replacement parts. That’s pretty cool.

4.  Shaft. Horizontal axial flow pump shaft, according to the different user procurement budget, can choose welding shaft, cladding shaft, shaft. ①Butt welding shaft, the full name is butt welding type hot cladding shaft, carbon steel shaft with excellent mechanical properties and corrosion resistance titanium shaft butt welding together, the outer surface of butt welding shaft is wrapped with a shaft sleeve, butt welding type hot cladding shaft can meet the requirements of corrosion resistance, high temperature resistance, wear resistance. ②Cladding shaft, a material with corrosion resistance is wrapped around a carbon steel shaft. ③Forging and forming one shaft. Heavy paired duty shaft provides maximum strength and stiffness in severe pumping conditions. The forging and forming shaft not only has corrosion resistance but also provides bearing capacity and operation stability.

5.  Bearing. Pre-loaded bearings for easy assembly and maintenance. The bearing box is designed for large space oil storage. There is oil level observation port, so that the bearing can be fully lubricated and cooled to ensure the long-term normal operation of the bearing.

Transmission part, the axial flow pump in the whole chemical process is to provide circulating power when the feed liquid is concentrated and crystallized, promote the circulation of the feed liquid, improve the heat transfer coefficient of the feed liquid evaporation process, avoid the damage to the crystal, often running at low speed. ZW Horizontal Axial Flow Pump is slow type axial flow pump technology, will not destroy the crystal, small cavitation margin, stable operation. It could be chosen belt pulley, reducer, connected electric motor. When the motor power is ≥200kw, it is recommended to choose universal joint drive and reduction gears.

■Application of Horizontal Axial Flow Pump

horizontal axial flow pump for salt making factory

Axial flow pump is suitable for high flow, low head conditions, conveying clear liquid or solution containing a small amount of crystallization.

  • Salt making requires evaporative forced circulation pump

  • phosphoric acid making process requires evaporation forced circulation pump

  • Mirabilite industry requires evaporation forced circulation pump

  • Alumina industry requires evaporation forced circulation pump

  • Sugar industry requires evaporation forced circulation pump

  • Water and wastewater treatment processes MVR project

  • Desalination projects circulating pump

  • Ammonium phosphate plant requires evaporation forced circulation pump

  • Combined alkali and ammonium ammoniate plant pump

  • Cold precipitation axial flow pump

  • Salt precipitation axial flow pump

  • Scrubber axial flow pump

  • The cooling axial-flow pump used in caustic soda plant evaporates the circulating axial-flow pump