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What is a centrifugal pump: graphite elements that compose it and main uses

The rotodynamic pump or better known as centrifugal pump, is a rotary type pump and currently the most used in the industry for fluid handling. These pumps have countless uses in different industries, including transforming the mechanical energy of the pump into the kinetic energy of a fluid.

What is a centrifugal pump: graphite elements that compose it and main uses

What is a centrifugal pump?

The rotodynamic pump or better known as centrifugal pump, is a rotary type pump and currently the most widely used in the industry for fluid handling. These pumps have countless uses in different industries, including transforming the mechanical energy of the pump into the kinetic energy of a fluid.

This device is the perfect complement in hydraulic installations and highly adaptable according to the industry.

Now that we know what a centrifugal pump is, we will explain the types that exist:

  1. Position of the axis of rotation: in which horizontal, vertical and inclined pumps are used.
  2. Shell design (shape): where the volute and turbine pumps are used.
  3. Housing mechanical design: where axially split and radially split pumps are used.
  4. Suction shape: single and double pumps are used.

Therefore, with this article we are going to know what is a centrifugal pump, and what is it used for, what are the fundamental parts and what are the specific applications of graphite as a mechanical component, how it works and its advantages.

Types of vacuum or sweep centrifugal pump?

It is the machine used to pump or evacuate fluids in general. Among the types of vacuum pumps, there are industrial blowers or sweep pumps with graphite components used as vanes on the rotor. It is important to mention that the pumps are rotary and, as mentioned before, they are pumps that transform mechanical energy into kinetic energy. That is to say, they accelerate or evacuate the particles of a fluid.

Once we have defined what a centrifugal pump is, we will explain the parts that make up the pump, focusing on the vacuum or sweep pump and its function:

Components

  1. Inductor or better known as stator: Fixed part that makes up the motor and consists of the steel frame that protects the magnetic core of the inductor, protecting the elements of the pump and dissipating the heat that is created inside the motor. Graphite gaskets resistant to high temperatures are used here.
  2. Air gap: This is the clearance that creates a gap between the rotor and the stator. Graphite braided packing is used to seal rotary movements.
  3. Casing: Body of the pump that contains and protects the internal mechanisms, since the material used for its manufacture depends on the fluid to be pumped. They are almost always made of cast iron, stainless steel or bronze when dealing with corrosive liquids.
  4. Bearing: Support and guide of the pump shaft, which is perfectly aligned of the different rotating parts that compose the pump.
  5. Turbine, impeller or rotor: Moving part of the pump composed of radial blades that impart kinetic energy to the fluid.
  6. Vanes: These are the graphite plates or blades that sweep air into the compression chamber. They are placed in slots in the rotating center (rotor) and can move radially, making contact with the wall of the compression chamber.
  7. Mechanical seal: Sealing element between the static and dynamic components of the pump, according to the pump, graphite seals may be used.

Operation

The vacuum or sweep function is carried out within the compression and/or vacuum chamber.

High rotor speeds exert centrifugal force on the graphite vanes, causing them to make tight contact with the chamber walls.

The eccentric position of the rotor within the compression chamber allows the graphite vanes to elongate or extend depending on their position.

Because of this, the fluid enters the chamber at the highest volume position z and is swept by the vanes to the lowest volume position. In this way the fluid is compressed and expelled from the chamber.

Conversely, the fluid enters at the lower volume position and would be swept to the higher volume position. Defining the operation of an industrial blower

Why graphite components?

Among the various types of centrifugal pumps, different graphite components are used. Among the qualities of graphite, we can highlight the following:

  • Low coefficient of thermal expansion
  • Self-lubrication
  • High temperature resistance
  • Durability
  • Sliding contact

These qualities make graphite an extremely important mechanical element. In addition, vacuum and compression pumps using graphite vanes have the advantage of expelling a clean fluid (air), without grease or oil residues like other types of pumps, for example piston pumps.

In ESGRAF we commercialize different grades of graphite for the elaboration of components such as vanes, seals and pipes.