HOW TO USE THE VERTICAL CENTRIFUGAL PUMP TYPHOON

Vertical centrifugal pumps maintain rotation concentricity through a wear bushing placed just above the impeller and must always be cooled. We have designed them so that this task is always performed by the working fluid, without the use of additional means, but it is important to remember that the vertical centrifugal pump should only be started when submerged at least up to the minimum level, never dry, to prevent the melting of fixed components.

Vertical centrifugal pumps are ideal when a continuous flow is required, but due to the high speeds and forces involved, it is preferable to avoid fluids rich in solid particles or highly corrosive, as they could damage the impeller and block the flow channels.

It is possible to handle fluids with viscosities up to 500 CPS or specific weights up to 1.9 kg/L by increasing the power of the motor. At the same number of revolutions [rpm], increasing the motor power does not affect the flow rate and head of the centrifugal pump but compensates for the increased effort due to heavier liquids.

A centrifugal pump is a very efficient but delicate machine. Knowledge of the plant and working fluid characteristics is necessary to choose the appropriate machine.

Due to their operating principle, centrifugal pumps create a suction vacuum. If the absolute pressure at the impeller inlet is lower than the vapor pressure of the working fluid, cavitation may occur (formation of bubbles of evaporated liquid and implosion on the impeller). Vertical centrifugal pumps by Fluimac must always be installed under a head, partially submerged. However, it is possible to control the maximum suction height through NPSH (Net Positive Suction Head) curves: The pump's NPSH (available) must always be greater than the NPSH required by the system, considering the geodetic height (height difference between the downstream and upstream tanks through which the fluid is moved), the pressure losses between these two sections, and the pressure difference between the free surface pressure of the downstream tank and the vapor pressure of the liquid.

In addition to the suction conditions, it is essential to know the characteristics of the discharge pipes because they influence the calculation of head. Before choosing the vertical centrifugal pump, it is necessary to know the head required by the system: at the geodetic height (height difference between the downstream and upstream tanks through which the fluid is moved), all the losses in the system due to friction and local factors need to be added. We can divide the losses into two types: distributed and localized. The first type depends on the flow of the fluid in the pipes, and knowledge of the dimensions and conditions of the pipes is required, while the second type depends on factors located in the system, such as bends, valves, or filters.

Finally, knowledge of the working fluid is required. Viscosity and density also affect the calculation of pressure losses and the choice of motor power.