Centrifugal pumps or dynamic pumps are the heart of most of the industries. Centrifugal pump is used to convert the driver energy of a fluid flowing through it into kinetic energy. This conversion is possible by accelerating the fluid to the outer rim of an impeller. The amount of energy imparted to the fluid is proportional to the velocity at the edge of the impeller. Now, if the impeller moves faster, greater energy is imparted to the liquid. Also, the bigger the impeller, the higher is the velocity of the liquid at the tip.
Working of a centrifugal pump explained in detail:
A centrifugal pump does not create pressure. It only creates flow. When a resistance is created to the flow of the liquid, it controls the kinetic energy of the liquid that is flowing out of an impeller. Pump volute or the casing is responsible for creating the first resistance that slows down the fluid. Due to this, some of the kinetic energy gets converted into pressure energy. The resistance to the pump’s flow can be measured by a pressure gauge. This instrument is attached to the discharge line.
The key hydraulic factors responsible for the performance of the pump must be close paid attention to. Here are a few key performance parameters of the centrifugal pump defined in detail:
- Friction Head (hf):
- size of pipe
- condition of pipe
- type of pipe
- the number of pipe fittings
- type of fittings
- flow rate
- nature of the liquid
- Velocity Head (hv):
- Pressure Head:
The concept of head is used for Newtonian fluids or true fluids such as water and petrol like non-viscous liquids. Hence, the term head is basically the measurement of kinetic energy created by the pump. It measures the height of a liquid column which the pump creates. Head measures energy of the centrifugal pump . The end users can describe the performance of a pump on any Newtonian fluid, be it as heavy as sulphuric acid or as light as gasoline, by using head. Here, head relates to the velocity gained by the liquid while moving through the pump.
In the pipe and fittings the head required to deal with the resistance to flow is known as friction head. Friction head depends on the following factors:
The energy created in a liquid due to its motion at some velocity say V is called velocity head. This factor is usually insignificant and is mostly ignored in high-head systems. However, in low-head systems, it can be a large factor and must be considered.
This factor is considered when a pumping system begins from or empties into a storage tank that is under some pressure. Here atmospheric pressure is not taken into consideration. The pressure in converted to feet of liquid.
What is added to system head?
- Vacuum in the suction tank
- Positive pressure in the discharge tank
What is subtracted from system head?
- Positive pressure in the suction tank
- Vacuum in the discharge tank
When we combine different types of head, it sums up to the total system head at a particular rate of flow.
Rotech Pumps has an experience of over sixty years in the business of engineering, manufacturing, designing and distribution of pumps, mechanical seals, valves and we offer sound pumping solutions which are backed by solid expertise.