Types of Pumps
The key to success with pumps is to get the right type of pump for the job. There are many types of pumps, but it is important to choose the right one for the job. The right type of pump can make a huge difference in the performance of your pumps. In this blog post, we will cover the different types of pumps and help the readers to understand about them.
We will discuss the following topics on this post regarding the Types of Pumps. This post is going to be useful for the readers handling the pumps for the various applications on board ships and in industries.
1) Pumps classifications (Primary).
2) Pump working principles.
3) Details of all type of pumps.
A pump is a machine for transferring a liquid or gas.
The conversion of pressure energy from mechanical energy is performed by pump.
Transfer of liquid to higher potentiality from the lower side is performed by pump.
The Pumps are of following two types
- Positive Displacement
Centrifugal pump works on the principle of centrifugal forces. A Vacuum creation takes place at the eye of impeller. Due to the vacuum a liquid or gas is inducted in.
Centrifugal force pushes the liquid or gas outward. Vanes convert the kinetic energy of the flowing fluid into pressure energy due to the shape of the casing.
Subcategories of Centrifugal Types of Pumps
As per the flow type, centrifugal pumps are of the following three subcategories.
1) Radial Flow
2) Axial Flow
3) Combination of Radial and mixed flow.
Radial Flow Pumps: – In these pumps, liquid flows in the perpendicular direction to the shaft. These pumps transmit the fluid at high pressure. These pumps have low handling of flow.
Axial Flow Pumps;- In the axial flow type pumps, liquid flows parallel to the shaft. In axial flow pumps, Liquid flows at high rate with low pressure.
Combination of Radial and mixed flow;- In these types of pumps, liquid flows in a conical pattern. The flow is a mixture of Axial and radial
Positive Displacement Pumps
This type of pump produces a depression at the inlet side. The pump draws the fluid in suction stroke and delivers the fuel at high pressure in discharge stroke.
The delivery of fluid is with a fixed quantity in each stroke.
The everyday use of these pumps is for the process with high pressure and fixed delivery.
These types of pumps are self-priming types.
Categories of Positive Displacement Pumps
These pumps are of following two categories basing on the flow of fluid.
- Reciprocating;- In this category the basic working principle is expansion and contraction. In the expansion pump draws the fluid through suction and discharges the fluid at higher pressure on the contraction.
The design of these pumps is of following type.
- Piston Pump.
- Plunger pump
- Bladder Pump.
- Diaphragm type pump
- Roller pump.
2. Rotary Types of Pumps ,
In these types of pumps Gear or screw creates the pumping space. The trapped fluid moves along the spaceand displace it to the discharge side.
Rotary pumps are of the following types.
- gear pump
- Screw Pump
- Cavity pump
- Lobe type pump
- Vane pumps
Most popular use is of Gear pump, screw and reciprocating pumps on board ships.
The gear pump is the category of positive displacement type pump. There are two gears in the gear pump, Drive gear, and driven gear. Both the gears rotate in opposite direction to each other.
During their disengagement movement gear teeth at suction side creates the suction. This process creates a vacuum to suck the fluid. Rotating gears carry the fluid with their rotation along with the casing.
This process transfers the fluid at the pressure on the discharge side. The engagement of gears creates the seal to develop high pressure at the discharge.
Screw pups are positive displacement type pumps and are self primed. These pumps consist of multi shafts with left and right hand screws.
Shafts rest on ball bearings.
During the rotation of the pump, fuel enters the suction port. Fluid propels along the body, and high-pressure fluid exists out at the discharge outlet.
The flow of fluid is axial along with the screw.
The screw displaces the fluid during its rotation.
The mechanical efficiency of the screw pump is better than the gear pump due to the design. The screw pump consumes moderate power than the gear pump, therefore savings of energy.
A safety valve in the outlet side of the screw pump prevents catastrophic failure. In the event of obstruction in the discharge line, the safety valve will operate avoiding damage to the pump.
Reciprocating Types of Pumps
This type of pump category has the piston and cylinder. The pump cylinder connects with the suction and discharge pipes with non-return valves. The non-return valves are uniflow type.
The piston rings seal the cylinder. connecting rods connects the piston with the driving shaft.
sub-categories of reciprocating Types of Pumps.
1) Single acting pump
2) Double-acting pumps.
Pump function is easily explained through the following diagram.
1) In the upward stroke, valve 1 closes due to the suction effect.
2) Valve 3 opens due to the pressure effect.
3) Another side of the assembly, valve 4 closes, and valve 2 opens, expelling the pressurized fluid.
During the downward stroke, valve 1 opens, and valve 4 closes, expelling the fluid to discharge. On the other side, valve 3 opens due to the suction effect, and valve 2 closes.
Air vessel reduces the pulsating effect at the discharge.
Advantages of Centrifugal Types of Pumps
- Discharge of fluid is with steady flow.
- These pumps don’t use air vessels for the reduction of pulsating effect.
- No relief valve.
- High discharge flow rate
Disadvantages of centrifugal Types of Pumps
- Low discharge flow rate.
- The usage of the pump is only with low viscosity fluids.
- The problem of high cavitations.
Advantages of Positive displacement Types of Pumps
- Pumps are self-prime type.
- Pumps have high discharge head pressure.
- The usage of the pumps is for high viscosity fluids.
No cavitation problem
- Pumps are self-prime type.
- Pumps have high discharge head pressure.
- The usage of the pumps is for high viscosity fluids.
- No capitation problem
Positive displacement Disadvantages -Types of Pumps -Types of Pumps
- Unsteady discharge flow
- It needs an additional component to reduce the pulsating effects.
- Low discharge flow rate.
Important Guidelines for the Pump maintenance
- Carry out the greasing of bearings regularly
- Check and maintain the Lube oil level of mechanical seals.
- Carry out the tightening of the gland packings carefully in case of any leakage.
- Replace the gland packings periodically.
- Check the power drawn by the pump motor in the running condition of the pump.
- Check the vibration of the pump regularly.
- Monitor the suction and discharge pressure of the pump while the vessel is on light load and fully loaded condition for the variation of NPSH.
- Check and tighten the coupling bolts.
- Clean the filters and strainers in the system line of the pump.
In alignment, we align the centreline of the pump with the centreline of the driver.
Alignment is very crucial in the case of the pumps using the rotating seals. A minor misalignment at the power end may cause the frequent failure of seal.
Problems due to misalignment
We are listing below the problems due to the misalignment.
- Misalignment can cause them to and fro the movement of the seal. To and fro movement of the seal will result in the opening up of the lapped face of the seal.
- A mechanical seal can’t support the misaligned shaft.
- There will be severe fretting on the shaft or sleeve.
- Pump bearing will have excessive loading.
- Parts of the seal will make contact and will result in damages.
- Wear rings will have the contact.
- The shaft will touch with a bush bearing at the end of the packing.
- The impeller will have contact with the pump volute/ back plate.
Important Points before the alignment -Types of Pumps
- The shaft of the pump should be straight and well balanced.
- Wear rings should be in good condition with correct clearance.
- Clearance between impeller to volute or back plate should be proper.
- End the soft foot on Pumpm and driver.
- Relieve the excess forces on the pump and pipes.
- Good condition bearings with proper clearance should be used.
- The mechanical seal should be with proper load on face. The seal should be as closer about the pump bearing.
Stages of Alignment
- Carry out the levelling of the pump and driver. Without levelling oil, the level will be challenging to maintain the lube oil level.
- Take many measurements in axial and radial directions to observe the location of the pump concerning the driver.
- Consider the operating temperatures of the units.
- Add the shims at required points/ foot.
Acceptable methods of alignment
- Reverse Indicator method;- This method is acceptable. But this method is time-consuming.
- This method is an accurate method for small diameter flanges.
- Axial float doesn’t affect the alignment.
- The use of flexible coupling is possible.
- Rotation of both the shaft is essential.
- Laser alignment method.;- this procedure f alignment is the latest method widely acceptable in industries.
- C and D frame adapter method;- This method is the easiest alignment method. This procedure takes care of thermal expansion problems.
Reason of vibrations in Pump
Listed below re the causes of vibrations in pump
- Suction starvation
- Vapour or gas lock in the fluid
- Gas in suction line.
- Insufficient Net Positive suction Head
- There will be steady misalignment in centrifugal pumps.
- Improper clamping of pipe lines
- Worn out or loose bearings
- Unbalance in rotating element
- Bent shaft
- Vibration transmission from driver
- Opening and closing period of shutoff valve is not matching with the the pump speed.
- Vibration in reciprocating pumps
- Fluid end leaky valves
- Poor condition of valves
- Insufficient lubrication i the pump rod, stuffing box and power end of pump.
- Worn out piston rings
- Gas or vapours in liquid
- Over speeding
Best Books on Pumps
Centrifugal Pumps. Selection, Operation, and Maintenance
An Introduction to Water System Pumps Operation and Maintenance
Introductory technical guidance for civil and mechanical engineers interested in operation and maintenance of water distribution system pumps. Here is what is discussed:
3. OPERATION OF PUMPS
4. PUMP MAINTENANCE
5. PUMP DRIVERS
8. PUMP SAFETY
9. MOTOR AND ENGINE SAFETY.
Pump Operation and Maintenance
This book was written to help every engineer, foreman, and mechanic charged with pump operation and maintenance to reduce costs. It can be used by personnel in every industry. Typical men who will find this book of much use include plant, mechanical, chemical,petroleum,marine sanitary, civil, irrigation, mining, power-plant,nuclear, and hydraulic engineers. Industries in which the procedures describe may be used include chemical, petroleum, textile, paper, food, power, marine, networking, mining, waterworks, sewerage,nuclear-energy, and Petrochemical
Pump Questions and Answers
Pump Questions and Answers – covering the construction, application, operation, installation, maintenance, and troubles of centrifugal, reciprocating, regenerative, rotary, and vertical turbine pumps,
Questions and Answers On Pumps and Pumping Machinery
This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it.
This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.
Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. To ensure a quality reading experience, this work has been proofread and republished using a format that seamlessly blends the original graphical elements with text in an easy-to-read typeface.
Pump Handbook: Third Edition
Newly revised, and bringing together the resources of international experts, this job-critical guide is the one and only guide to the design, application, specification, purchase, operation, and maintenance of pumps of all kinds. Covering everything from advanced seals to basic design paradigms, the Pump Handbook takes you through all the latest developments in pump technologies. This important update, the first in 14 years, offers practical guidance to help you:
*Design leading-edge pumps of all types for any uses.
*Select and purchase the right pump for your application.
*Specify materials, drivers, valves, piping, intakes, and other components—using both SI and Customary Units.
*Choose and apply controls and valves
*Install and operate any type of pump.
*Test, maintain, and troubleshoot pumping equipment and peripherals.
*Find details on centrifugal, jet, positive displacement, and other pumps.
*Keep state-of-the-art reference data and resources always at hand.
Centrifugal Pump Handbook
This long-awaited new edition is the complete reference for engineers and designers working on pump design and development or using centrifugal pumps in the field. This authoritative guide has been developed with access to the technical expertise of the leading centrifugal pump developer, Sulzer Pumps. In addition to providing the most comprehensive centrifugal pump theory and design reference with detailed material on cavitation, erosion, selection of materials, rotor vibration behavior and forces acting on pumps, the handbook also covers key pumping applications topics and operational issues, including operating performance in various types of circuitry, drives and acceptance testing.
The Practical Pumping Handbook
The Practical Pumping Handbook is a practical account of pumping, piping and seals starting with basics and providing detailed but accessible information on all aspects of the pumping process and what can go wrong with it. Written by an acknowledged expert with years of teaching experience in the practical understanding of pumps and systems.
“The real value of this book is how easy it is to read and understand. I have bought several copies for our Technicians in the mill, and it will be provided to individuals as they enter our Pump and Mechanical Seal training program
Handbook of Pumps and Pumping
Written by an experienced engineer, this book contains practical information on all aspects of pumps including classifications, materials, seals, installation, commissioning and maintenance. In addition you will find essential information on units, manufacturers and suppliers worldwide, providing a unique reference for your desk, R&D lab, maintenance shop or library.
* Includes maintenance techniques, helping you get the optimal performance out of your pump and reducing maintenance costs
* Will help you to understand seals, couplings and ancillary equipment, ensuring systems are set up properly to save time and money
* Provides useful contacts for manufacturers and suppliers who specialise in pumps, pumping and ancillary equipment
We hope you enjoyed our blog post about Types of Pumps. In this blog, we outlined the different types of pumps and what they are used for, along with their function, size, and more! Keep in mind that these are just the most common types of pumps and there are plenty of others out there. Please let us know if you have any questions or comments by visitinghttps://www.marinediesel.co.in/contact-us/. Thank you for reading, we would love to hear from you!
Good Luck !!