Last Updated on May 5, 2023 by asifa
A dynamic pump is a variable device that can use a selection curve (for positive displacement pumps) instead of a graph. Also, the size of the pump must be large enough to consider the effect of the oil viscosity. Dynamic Pump is a velocity pump in which moving energy is added to a liquid as the flow rate increases. When liquid exits the pump before it enters the drain pipe or goes down, an increase in energy is generated to raise the energy (pressure).
The real difference between dynamic pum ps and positive displacement pumps is how they work with the valve closed. The displacement pump physically circulates the liquid, so closing the valve in the displacement pump creates a constant pressure which can cause the tube or pump to fail. The difference with variable pumps is that they can operate safely with the valve closed (for a short time).
Table of Contents
Type of Dynamic Pumps
1) Radial flow pump
This type of dynamic pump is also called a centrifugal pump. The fluid enters along the axis or in the center, is accelerated by the impeller and exits at a right angle (radial) to the axis. For example, a centrifugal fan is commonly used to run a vacuum cleaner. Another type of radial flow pump is the vortex pump. The liquid moves in a tangential direction around the working wheel. The conversion of the mechanical energy of the motor into potential flow energy takes place via several vortices excited by the impeller in the working channel of the pump. In general, axial flow pumps operate at higher pressures and lower flow rates than axial flow pumps or mixed flow pumps.
Centrifugal pumps are relatively simple in nature. They use the kinetic energy of the motor to move liquids. The motor is connected to the shaft and then the impeller of the pump is rotated, reminiscent of the “water wheel” on an old ship. The rotation passes the water through the entry point of the shell and is eventually released.
2) Axial flow pump
They are also called full fluid pumps. The liquid is pushed in or out to move the liquid on the axis. This dynamic pump operates at lower pressures and flow rates than radial flow (centrifugal) pumps. Without special precautions, the axial flow pump cannot accelerate.
At low flow rates, the increase in total head and high torque associated with the pipe means that the starting torque must be a function of the acceleration of the complete liquid mass in the pipe system. If there is a lot of liquid in the system, slowly increase the pump speed. Mixed flow pumps are a compromise between radial flow and axial flow pumps. The fluid undergoes radial acceleration and lift and positions the impeller in the position 0 to 90 degrees from the axial direction. Therefore, mixed flow pumps operate at higher pressures than axial flow pumps, while having higher flow rates than radial flow pumps. The outlet angle of the flow determines the discharge characteristics of the head associated with the radial and mixed flow.
Centrifugal pump drying danger:
- Pump bushing and bearing are damaged due to overheating.
- Shaft mismatch
- The sealing ring is damaged
- The wear ring is broken
- Damage to the butterfly
Advantages of Dynamic Pumps:
- Small size, space saving, low capital cost
- The dynamic pump requires low maintenance.
- There is no danger of closing the drain outlet on start-up.
- Management of large quantities
- Ability to work head down
- Able to work in low and medium viscosity liquids.
Disadvantages of the Dynamic Pump
- Additional initial P / P required.
- Not work high head.
- Not suitable with high viscous fluid.
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