Learn - Sep. 05, 2022
An Axial flow pump, is a high flow rate and low head fluid pumping equipment, which is 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. The axial flow pumps are widely used in agricultural drainage and irrigation, urban water supply and drainage, water transfer engineering, salt making, desalination project... Strictly speaking, it is not a centrifugal pump, its shape is also different from the common chemical centrifugal pumps, 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. 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.
The horizontal axial flow pump is composed of the pump par and the transmission part. The pump is composed of the impeller, pump casing, shaft, bearing box and other components. The structure of horizontal axial flow pump as below:
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.
The pump casing is also known as 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. The axial flow pump can be mounted by hanging on the pipe, with advanced thermal compensation technology. The installation of ZW horizontal axial flow pump can be done without the base plate, and there is no expansion joint on the entire pipeline, which can save a lot of procurement costs for the end user. Therefore, our horizontal axial flow pumps are often used with evaporator, crystallizer, reactor, cantilever installation structure is conducive to coordination and unity with the evaporation system.
According to the working condition, there are different shaft sealing systems for axial flow pumps, but generally the most widely used are packing seal, single mechanical seal, or double mechanical seal.
■Packing seal, efficient and simple, packing seal for inner and outer sealing, replacing packing, no need to stop operation, so it is really fast and convenient.
■ Single mechanical seal, conforms to API682, flush Plan02 or Plan32 or Plan54. Choose the flushing water pressure according to the requirements of working conditions. The flow rate is usually 3-26L/min. Turn on the flush water 5 minutes before starting the axial flow pump, and then turn it off 5 minutes after stopping the axial flow evaporation forced circulation pump.
■ Double 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 flush water 5 minutes before starting the propeller pump, and then turn it off 5 minutes after stopping the operation.
Mechanical seal can achieve no leakage, no pollution to the environment, so that the service life of the horizontal axial flow pump is longer, ensuring the safety of the working environment, ECO-friendly. Most of the end users choose mechanical seal as the shaft sealing system for their axial flow pumps.
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.
The shaft of an axial flow pump, according to the different user procurement budget, can choose butt welding shaft, cladding shaft or complete 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.
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.
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 evaporative 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 evaporators
