A pump is a mechanical device used to transfer fluids from one place to another place. According to the working principle, pumps divide into two categories. The first type of pump is a Positive displacement pump, while the second is a dynamic pump. This article mainly explains the dynamic pump types, working, applications, and some other aspects.
What is a Dynamic Pump?
A dynamic pump is a type of pump that delivers kinetic energy to the working fluid through the action of axial or centrifugal force, which then transforms that energy into an increase in pressure or flow rate.
A dynamic pump is also known as a kinetic pump because it pumps the fluid by providing kinetic energy. This pump most commonly uses a centrifugal force to pump the fluid. Dynamic pumps are used for applications that require a continuous flow rate.
These types of pumps contain an impeller, diffuser/volute casing, and housing.
The main difference between a dynamic pump and a positive displacement pump is their working method. Dynamic pumps use a rotating impeller to generate a cavity, while a positive displacement pump uses a reciprocating part (such as a piston or plunger) to generate a cavity.
The dynamic pumps have fewer rotatory components than the positive displacement pumps. They have low weight than the PD pumps.
A centrifugal pump and a submersible pump are the most common examples of the dynamic pump.
Working Principle of Dynamic Pump
A dynamic pump is a type of pump that uses a centrifugal force to transfer fluid from one place to another. A rotating part (such as a rotor or impeller) generates this centrifugal force.
As the fluid passes through the impeller, it provides kinetic energy to the fluid and increases fluid velocity. After passing through the impeller, when this high-velocity fluid passes through the volute casing, it slows the fluid and converts the fluid velocity into pressure energy. After this process, the outlet valve opens, and fluid is discharged to the desired area.
Read Also: Types of Positive Displacement Pumps
Types of Dynamic Pumps
The dynamic pump has the following major types:
- Submersible pump
- Centrifugal Pump
- Axial Pump
- Hydrant System
- Horizontal Centrifugal Pump
- Vertical Centrifugal Pump
1) Axial Pump
The axial pump is one of the most famous types of dynamic pumps. These pumps are utilized for high flow rates at the comparatively short delivery head. So, the energy transfer from the axial pump takes place only through the flow-related process.
In an axial pump, the liquid is parallel to the shaft of the pump. In these pumps, water enters radially while discharges axially.
Read More: Axial Pump Working and Types
2) Centrifugal Pump
A centrifugal pump is a type of dynamic pump that uses centrifugal force to convert mechanical energy into hydraulic energy. The conversion of energy occurs through the two major components of the pump: volute casing and impeller.
The main purpose of the volute casing is to gather the liquid exiting the impeller and transform the fluid velocity into pressure energy.
These dynamic pumps are most commonly used to pump liquids from the low head to the high head. These dynamic pumps are used in pharmaceutical, septic tanks, chemical, mining, petroleum, power plants, municipal, agriculture, and other fields.
Read More: Centrifugal Pump Working and Types
3) Vertical Centrifugal Pump
A vertical centrifugal pump is also known as a cantilever pump. They have a unique shaft and bearing mount configuration that permits the volute to swing in the sump while the bearings are installed out of the sump.
These pumps don’t need a stuffing box for shaft sealing but use throttle bushing. This pump takes very low installation space. It is the best option If you want to install a pump in a limited surface area. They are ideal for high-pressure and hot fluids.
4) Horizontal Centrifugal Pump
The shaft of a horizontal centrifugal pump usually installs horizontally between overhung or bearings. This type of pump has easy installation and maintenance, with easy access to internal components.
You must select the right shaft design to deliver the required pump pressure. The horizontal pumps are ideal for low-suction applications, and high-suction requires a built-in bearing shaft.
On the other hand, horizontal centrifugal pumps take up a larger space when the facility has concerns about the space occupied. However, these pumps have low operating temperature and pressure than the vertical pumps.
5) Submersible Pump
A submersible pump is mechanical equipment that works by pushing the water toward the surface instead of pulling it. It has a hermetically sealed motor connected to the pump body that helps to push the fluid toward the surface.
These types of dynamic pumps are most commonly used for slurry pumping, general industrial pumping, sewage pumping, septic tank pumping, and drainage.
Read Also: Working of Submersible Pump
6) Hydrant System
A hydrant system is a water source that supplies water at sufficient pressure and flows through a network of nozzles, pipes, and hydrants throughout a building for firefighting applications.
This pump has a series of pipes linked directly to the key water supply to supply water to each hydrant outlet in the event of an emergency.
Each hydrant pump has multiple discharge valves to which you can connect a fire hose. This hydrant system assists firefighters in fighting the fire suppression process. The hydrant system increases firefighters’ ability to control fires in the construction site in which it is placed.
Read Also: Different Types of Pumps
Advantages and Disadvantages of Dynamic Pumps
Advantages Dynamic Pumps
- These pumps have small sizes.
- They need a short space for installation.
- They have less cost.
- The maintenance of a dynamic pump is easy as compared to the positive displacement pump.
- They can control low to medium-viscosity fluids.
- They are best for low-head to medium-head applications.
- They provide a continuous supply of fluid.
Disadvantages of Dynamic Pumps
- These types of pumps have shaft misalignment problems.
- They have issues related to impeller damage.
- Wear a ring of this pump damage in a brief period.
- They have seal ring damage problems.
- The bearings of these pumps damage very quickly due to overshooting.
- They have priming issues.
- They need manual priming.
Applications of Dynamic Pumps
- These pumps are widely used for pumping crude oil.
- Dynamic pumps are used in the chemical industry.
- They use for commercial and household applications.
- These pumps use in the food industry.
- These pumps are widely employed in fire protection industries.
- They use for cellulose, petrochemical, hydrocarbons, paint, and beverage production.
Dynamic Pump Vs Positive Displacement Pump
The main difference between a dynamic pump and a positive displacement pump is given below:
| Dynamic Pump | Positive Displacement Pump |
|---|---|
| A dynamic Pump provides kinetic energy to the fluid to pump it from one area to other. | A positive displacement pump transfers the fluid by trapping it in a closed cylinder. |
| It uses an impeller and diffuser to pump the fluid. | It uses a reciprocating or rotary part (such as piston, diaphragm, screws) to pump the fluid. |
| The flow rate varies according to the pressure variation. | The pressure variations don’t affect the flow rate. |
| As the fluid viscosity increases, the pump performance reduces due to the pump’s internal friction losses. | The viscosity doesn’t affect the performance of the positive displacement pump because internal clearance easily handles the viscosity changes. |
| The dynamic pump has the highest efficiency at a specific pressure. As you change the pressure, the pump efficiency also changes. | The pressure doesn’t highly affect the performance of the positive displacement pump. |
| It has cavity issues. | It doesn’t have cavity issues. |
| The dynamic pumps need initial priming. | The positive displacement pumps are self-priming. |
| The desired power for a dynamic pump is higher than the PD pump. | It requires lower for driving. |
| It has a low cost. | It is an expansive power. |
| The dynamic pump has the following examples: 1) Centrifugal Pump 2) Axial Pump 3) Submersible Pump 4) Septic Tank Pump 5) Multistage Pump | The positive displacement pump has the following examples: 1) Reciprocating Pump 2) Rotary Pump 3) Screw Pump 4) Diaphragm Pump 5) Plunger Pump |
FAQ Section
What are the types of Dynamic Pumps?
The dynamic pump has the following major types:
- Centrifugal Pump
- Axial Pump
- Vertical Centrifugal Pump
- Horizontal Centrifugal Pump
- Submersible pump
- Hydrant System
- Multistage Pump
What are the Dynamic Pump used for?
Dynamic pumps are most commonly used for low-head to medium-head applications. They are best suitable to pump low-viscosity fluid. Dynamic pumps are used for continuous fluid flow applications. They are most
What are the parts of Dynamic Pump?
The dynamic pump has the following major parts:
- Impeller
- Casing
- Diffuser
- Shaft
- Electric Motor
- Crankshaft
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