Friday, October 23, 2020

Basics of reciprocating pump

Reciprocating pump

Reciprocating pump is a mechanical device which is used to discharge or transfer liquid from one source to another source with high pressure and fixed volume approx. It is a type of positive displacement pump.
Reciprocating pump converts mechanical energy into hydraulic energy by sucking the fluid from the sump into the piston cylinder where the liquid is discharged through the discharge valve.
Now we will discuss the construction of reciprocating pump below the list of main components of a reciprocating pump is piston, piston rod, connecting rod, piston cylinder, rider ring, cross-head, crankshaft, suction valve, discharge valve, piston ring, flywheel, shaft couplings, end cover, cylinder lubrication oil, lubrication oil pumps.
With the help of assembly, of the piston rod, connecting rod and crankshaft converts the rotary motion into the reciprocating motion. And the compression is going on with the help of reciprocating the motion of the piston.
which moves backward and forward motion in a tightly closed cylinder. In the assembly of piston, piston rod, connecting rod and crankshaft connecting rod and crankshaft.  the is directly connected through a cross head. The rotary motion converts to the reciprocating motion with the help of the cross head. As shown in the figure.
reciprocating pump cylinder

What is the working principle of reciprocating pumps?

The reciprocating pump suction valve is connected with suction line and discharge valve flange is connected with discharge line. When piston moving in a backward direction, the liquid sucks through the inlet valve into the cylinder and when piston starts moving in the forward direction inlet valve will close and the liquid inside the cylinder will start pressurizing the piston.
And moves in the forward direction that some pressure also creates on the discharge valve due to this pressure discharge valve will be open and liquid will start escaping from the cylinder after the completion of this process discharge valve closed. The piston movement start in backward direction and the liquid also starts sucking from inlet valve this process goes in each time the same this is the working principle of reciprocating the pump.

How do you know which pump is the centrifugal pump and each reciprocating pump?

  • With the help of the pump casing design.
  • In a reciprocating pump mostly, dampener is used to give the uniform flow.

Where is the reciprocating pump used?

Reciprocating pump used for high pressure, high viscosity fluid and control flow (uniform flow).

How many major parts are used in reciprocating pumps?

The parts name I have already mentioned you can check from here.
reciprocating pump is piston, piston rod, connecting rod, piston cylinder, rider ring, cross-head, crankshaft, suction valve, discharge valve, piston ring, flywheel, shaft couplings, end cover, cylinder lubrication oil, lubrication oil pumps

What do you mean by the stroke in the pump?

The stroke is used to control the flow by adjusting the piston movement. The stroke is directly proportional to the flow rate. It is an adjustment setting of a piston and connecting rod (tight or loose). And piston road where we can set the stroke of the piston.

How do you identify which one is single acting and which one is a double acting pump?

A single acting pump, one section line and one line discharge line connection is used in one cylinder. The suction of the liquid will be in backward movement and discharge will only be in forward direction only. Whereas in the double acting reciprocating pump on the same cylinder, two suction lines and two discharge line connections were used.
In the double acting reciprocating pump, the one tine suction and discharge of the liquid complete in backward and same operation will be continued in forward movement. So, the delivery and suction of the liquid in both directions. In the double acting cylinder, the piston movement is between both one section valve and one discharge valve. One section one discharge valve at the start of the cylinder other is the end of the cylinder.

Why use the double acting reciprocating pump?

This type of pump is used for linear flow, high head, high pressure and without more fluctuations in the flow. 

Which pump is used for dodging the chemical in the tank?

Most reciprocating pumps are used for dodging purposes. It is used for control flow and higher pressure. The discharge flow rate required for dozing chemicals is very low and this one can only be handled by reciprocating pumps.

What is the valve condition during the operation of the reciprocating pump?

During the operation of reciprocating pump when the suction is going on in the cylinder suction valve is open and during the discharge of the liquid the suction valve will be closed and discharge valve be open this is sequential process and automatic by the help of low pressure and high pressure in the cylinder.
There are many types of valves used in reciprocating pumps.

How many types of valves are used in reciprocating pumps? 

Suction and discharge valve are a non-return valve. Which is open in one direction only poppet valves, plate valves and nrv etc.   

Why is the dampener used in reciprocating pumps?

Dampener is used for controlling the flow and fluctuation of the liquid.

Which gas is used to dampener?

nitrogen is used for dampeners.

Why priming is not required in reciprocating pumps.

The chance of cavitation in the cylinder is very low because if some bubbles are shocked in the cylinder It is collapse during the discharge or escapes through the discharge valve because the suction valve will be closed during the discharge process. There will be less chance of air pockets in the inside body.

What is the SOP of reciprocating pump single acting?

  • Check the nitrogen pressure in the damper.
  • Check the lubrication of all parts.
  • All types of lubrication have been given in running conditions after that motor starts.
  • The pump operation will start during the start of the motor.
  • Before the start pump all suction and discharge valves should be in open conditions.

What is separation of reciprocating pumps?

Preventive measures for separation of reciprocating pumps. If the pump cylinder pressure goes below the vapour pressure of liquid and dissolved gases will be liberated from the liquid then cavitation takes place. The continued flow of the liquid is not possible due to this separation of liquid taking place.

Friday, October 16, 2020

Characteristics of positive displacement pump

Characteristics of positive displacement pump

The positive displacement pump gives approx. a constant flow at a wide range of pressures. Mostly positive displacement pump use for deliver high viscosity fluid. This type of pump is three types rotary, reciprocating and linear. This type of pump operates at the initial stage with always turn the valve in open condition because It has not shutoff head and continues to discharge the liquids, the cause of leakage in discharge line.


Pressure vs flow rate chart

Now in figures you can see centrifugal pumps flow rate is varying with respect to pressure where, as in the positive displacement pump more or less constant flow regardless of pressure as showing line showing in the graph.


Pressure vs flow rate chart

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You can see in the flow rate vs viscosity graph loss of flow as the viscosity goes up in centrifugal but the positive displacement pump’s flow actually increases. This is because the higher the viscosity liquids fill the clearances of the pump cylinder body more as compared to other causing pump and give higher volumetric efficiency.


Net Positive Suction Head Requirements

In centrifugal pump, the NPSHR varies respect of flow which is determined by pressure and viscosity as discussed above. In a PD pump NPSHR varies as a function of flow which is determined by speed. The lower the speed of a PD pump, the lower the NPSHR required.


 Characteristics curve of positive displacement pump

The characteristic curve of (HQ curve) a positive displacement pump showing in figure. H(Head) Q(flow) characteristic curve when positive displacement pumps that we have taken as an example. you know the working principle of reciprocating the pump. because reciprocating pumps is also a category of PD pump rather than Positive Displacement pump. I said that apart from the reciprocating pump there are many other types of pumps like screw pump, vane pump, gear pumps that also you know falls under the category of positive displacement pump. So, here we are discussing the HQ curve of reciprocating pump.




 Characteristics curve of PD pump

We have discussed the working principle of reciprocating pump how this pump works?

The pump sucks fluid from the sump then it discharges to the delivery tank. You know suction stroke and delivery stroke which is connected by a crank and connecting rod mechanism so the linear motion of the piston created by the crank and connecting rod also depends upon the frequency of the rotation of the crank speed. We have discussed that if we try to draw the HQ curve of a PD pump then the HQ curve looks like as show in figure.

So, the discharge noted by Q and discharged is by H. We try to you know develop the HQ curve for this kind of pump, then how will we get it? We have discussed that the PD pumps you know positive displacement pumps are this HQ curve is like this normally this class of pumps are used to deliver high head against an almost constant flow rate.

This is a characteristic feature of the positive displacement pump. So, it is normally used to deliver a high head against a constant speed here that remains almost constant flow rate. We have discussed that normally whenever it discharges from the open end of the cylinder to the close end of the cylinder.

Then it discharges water to the delivery sump and then high pressure develops because of that high pressure there is a leakage of some amount through the glands and as a result of which we get an actual curve which looks like this in figure.

Because of the leakage through glands the reciprocating pump performance is totally dependent on volume capture in cylinders. But if the speed is higher or fluctuating in reciprocating pump leakage chances also increase. 

Slip factor is the difference between theoretical discharge and actual discharge of a same pump. Due to some losses during the operation the pump slip factor was affected.

When the discharge pressure is increasing with increasing the head of the fluid because of the losses in friction, like slip and other types of mechanical parts rubbed.

Discharge and speed graph

In this curve is a linear line showing because if speed is increased the discharge pressure after reach the beyond limit of speed the linear line going to Flat. While the speed of the pump increases, the chances of leakage are also increasing, with other losses. 


Efficiency and head graph

Efficiency and head curve lines sowing approx linear but efficiency is totally dependent upon the head of the pump. 




 learn from other sources

Sunday, September 20, 2020

What is plain bearing

Sleeve bearings

Sleeve bearings are one of the most common and efficient types of bearings.We will show you the basic types of sleeve bearings and try to point out the differences between them and other types of bearing. There are two basic categories of bearings which are widely used in industry today: sliding contact bearings and rolling contact bearings.

The rolling contact bearings, also referred to as anti-friction bearings, rolling contact bearings utilize balls or rollers to reduce friction. Which rolls between the two races thereby cutting down on friction. The other category is made up of sliding contact bearings like this also referred to as sleeve or plane bearings A sleeve bearing is a non-moving or rotating surface on which a moving part such as a shaft slides or rolls. It has no balls or rollers and usually depends on some type of lubrication to help reduce wear and friction. You will often hear sleeve bearings referred to as journal bearings - well this is only partially true. We say it's only partially true because all of these bearings, the rolling contact and the sleeve bearings, may be referred to as journal bearings. The term journal is the name for the part of the shaft which fits inside the bearings therefore both rolling contact and sleeve bearings can be considered journal bearings.

Sleeve bearing clearance

Plain bearing

Types of plain bearing

However, the sleeve bearing there are two basic types of sleeve bearings now in common use they are the single piece type and the split type of course.

a properly installed and lubricated sleeve bearing will often last as long as the equipment. It's mounted in another variation in sleeve bearing and has to do with the thickness of the bearing.

The wall thickness can vary considerably depending on the application and the requirements of the equipment.

The advantages and disadvantages Sleeve bearing

Advantage Sleeve bearing

  1.  Sleeve bearings can support very heavy loads at high speeds.
  2. They usually require less radial space for installation, which is a very important consideration in some machines and equipment.
  3. Sleeve bearings are also normally quieter in operation than most rolling contact bearings since they have no moving parts because of their solid construction.
  4. They are much more resistant to unexpected overload and shock condition contamination, such as dirt dust and other foreign particles, and are less likely to damage sleeve bearings than precision rolling contact bearings.
  5. This is true because the smaller particles will embed themselves in the soft-bearing material, resulting in less damage to the bearing of another.
  6. Advantages they do not require as much care in storage sleeve bearings may be stored just about anywhere.
  7. Indefinitely with a minimal amount of deterioration, this is not true of rolling contact bearings.

Disadvantaged of Sleeve bearing

  1. The disadvantage of sleeve bearings is that they require more axial or linear space than a comparable rolling contact bearing.
  2. They generally require considerably more lubricant than comparable rolling contact bearings.
  3. Sleeve bearings also create a greater load on the driver during start-up.
  4. Since the shaft is riding directly on the bearing at which time there is a greater chance of damage to the shaft journal and would be the case where rolling contact bearings are used.
  5. However, once it reaches operating speed, the friction decreases since the shaft is riding on an oil film and not directly on the bearing itself.


Metals used in plain bearing manufacturing

The bearings themselves may be manufactured from several different metals depending on their application.

It is usually made of cast iron, bronze or aluminium sleeve bearings with a shell of aluminium or bronze that may have a lining or they may not however sleeve bearings with a shell of cast iron will normally have a lining such as the Babbitt lining being pointed out. Here the lining or coating which is used in sleeve bearings may be made of a variety of materials such as aluminium, copper lead cadmium base / plated silver and Babbitt of all the different metals a tin or lead based Babbitt is the most commonly used Babbitt is an alloy made of several metals. Which is applied as a thin coating over the shell enlarger sleeve bearings for heavy-duty equipment a thicker layer of Babbitt is used to line a rigid backing of steel-bronze or cast iron you are not expected to select bearings for use in equipment the manufacturer of the equipment will specify exactly what type of bearing is to be used. This is true because sleeve bearings are often designed specifically for a certain application.

Working principle of plain bearing

 A film of lubricant between the shaft and the bearing separates the two parts during the operation, reducing friction and also helping to dissipate any heat. This is generated by the lubricant and may be introduced into the bearings by a variety of methods force feeding lubrication systems. here are used frequently to pump oil through the bearings of various machines if grease is used as a lubricant it may be introduced through one of several methods and this would include grease fittings or a grease pocket as shown in this illustration another common method of lubricating sleeve bearings with oil is the use of oil rings which pick the lubricant up out of a sump below the bearings and carry it up to the bearings as the rings rotate on the shaft?

 Since there is such a variety of Lube systems in use, we won't go into detailed explanations of how they work in this course. You should already be familiar with the basic systems now in use once the lubricant reaches the bearing itself, the bearing design takes care of the distribution of the lubricant along the shaft journal, for instance, this bearing is lubricated by grease, the grease is forced downward by gravity through a slot at the top of the bearing until it comes into contact with the shaft. You won't encounter this type often since most sleeve bearings are lubricated with oil and not greased oil lubricated bearings are a different story, a force-fed Lube system in which the oil reaches the bearings and is distributed along the shaft through oil grooves. Which is machined into the surface of the bearing itself the workman is now pointing to one type of groove known as an axial groove?

Since it is parallel to the axis of the shaft note that the groove stops short of the end of the bearing. This is to prevent the lubricant from running out of the end of the bearing during operation of the machine this is called a circumferential oil groove. It channels the flow of lubricant around the circumference of the shaft, and bearing circumferential oil grooves are also used as collector grooves. The bearing of the oil flows along the length of the bearing then collects in this oil come channeled back to the oil sump. Through these drain passages from the groove, this arrangement helps to prevent leakage of the lubricant out of the end of the bearings of his bearing is pressure lubricated.

 The two basic types of sleeve bearings,  the split sleeve and the solid sleeve, were designed to restrict the radial movement of the shaft during operation of the machine. These sleeve bearings with a thrust shoulder are designed to restrict both the radial and axial movements of the shaft. There is a split sleeve bearing with thrust shoulders being pointed out as you can see the thrust faces are also coated with the same Babbitt lining.

Which is used on the inside of the bearing sleeve bearings with thrust faces will normally have oil grooves which run all the way to the ends as shown here this is necessary since lubricant must be supplied to the thrust faces of the bearings. Oil grooves in the thrust face like these then distribute the oil across the face of the bearing during operation, as with the basic sleeve bearing, there is a film of lubricant between the shoulder on the bearing and the bearing surface of the rotating assembly, this type of sleeve bearing then controls both the radial and axial movement of the shaft.

Thursday, September 10, 2020

What is balance drum and disk

What is the balance drum?

Balance drum in centrifugal pump

It is a device which is used to balance the axial thrust build-up by impeller. it is also used with thrust bearing which is transfer very less residual thrust load to thrust bearing.

This is the main benefit of drums. The balance drum is a circular device installed on pump rotor generally drum is installed on the discharge end side.

What is the balance disk?

Balance disk in centrifugal pump

The balance disk is use for compensate axial thrust and capable to compensate fully generated thrust load. The balance dick is used to manage axial clearance between casing and rotor disk. The balance dick is used immediately just after the last stage so it has full discharge pressure on one side of the disk.

What is balance piston?

Balance piston

The balance piston is also called the balance drum.

What is axial thrust bearing?

Thrust bearing

The residual axial thrust is always present in the system to compensate for this thrust using axial thrust bearing.

What is flange drum?

Flange drum is used in the combination of balance drum and balance disk. But principally depending on hub leeway.

What is stepped drum?

It is also used in the combination of balance drum and balance disk. But principally depending on hub leeway.

What is the difference between a balance disk and a balance drum?

Balance drum vs Balance disc

Both are used for compensate thrust load. Drum is use for managed high axial thrust and generally use in discharge end. The pressure acted on drums on both sides (left and right) and cancelled out to each other.

Balance line

The balance line is system use to compensate for generated thrust load by discharging fluids. the balance line is provided from the pump suction side to discharge side. To nullify the axial thrust generated by impeller discharge use a balance line also. Because of this back force the internal part will be damaged so a taping is given from discharge to balance drum.

Learn centrifugal pump 

Thrust load

Two types of thrust load are applied to bear axial thrust and radial thrust. Below is an example of the axial thrust mentioned. 

We will discuss boiler feed water pumps. It is also a multistage centrifugal pump. Suppose that in this pump suction pressure is 7 kg per centimetre square and discharge pressure is approx 130 kg Per centimetre Square at final outlet in 6 stage pumps.

According to this condition, in the first stage, impeller suction pressure will be around 8 kg per centimetre square due to the increase in velocity with the help of diffuser. 

The first stage of centrifugal multistage pump circulating Liquid on the periphery of casing around the Imperial Outlet. Suppose that at the impeller First stage discharge pressure is increased to around 20 kg per centimetre square. 

Due to this 20 kg Per centimetre Square in Outlet it will generate back pressure approx 20 kg/centimetre square and that force pushes the impeller assembly in backside according (Newton's third law of motion: 'Every action has the same and opposite reaction.). 

In the next 2nd stage, the suction pressure at inlet around 20 kg per centimetre square and discharge Pressure will be around 40 kg per centimetre square. 

Due to the same phenomena that occurred with the Second stage impeller also and the second stage discharge liquids also pushed the rotor assembly in back side after that liquid goes forward to the stage. This process is continued till the last stage. 

To balance this type of generated back Force, use three parts with pump casing, rotor assembly balance disc, balance drum, Balance line. And in the place of bearing or with the bearing to bear thrust load Thrust bearing is also provided. 

But the thrust bearing is not sufficient only for compensate hundred percent thrust load So Balance disc, balance line or balance drums used to reduce  net thrust use impeller in opposite to each other.

Sunday, August 30, 2020

What is LOTO

LOTO (Lockout-Tagout)

Lockout-Tagout system is mostly use in industries for safety of work men. In the LOTO system each department have self-color lock to isolate electrical system of equipment. Sometime LOTO are used for inlet and outlet pipe line's valve isolation. 
Every year globally many incidents are caused by improper control of hazardous energy and failure to follow Lockout-Tagout. 
Potential Hazardous energy comes in many different forms such as Chemical, Electrical, Hydraulic, Mechanical, Pneumatic, Thermal, OR Other source of energy.  below the picture of lock and tag.


Where LOTO is required?                                                                                        

When a workman is required to remove guard, maintenance job on equipment or any part needed to be change of the equipment. Tagout never should be use alone to isolate energy any types.
Simple Lockout.
Accomplished by individuals placing personal lock and tags directly on the point of isolation.
Complex Lockout.
Person is change as responsible for keeping all the hazardous energy source hazardous   material and Electrical.

Requirement for Lockout-Tagout devices

    •  Following requirements are adhered to while applying Lockout-Tagout Devices must be Substantial enough to present removal without excessive force.
    • Clearly indicating details of employee who installed the device.
    • Uniquely identified.
    • With one key only.

Lockout -Devices

Five colored locks for different discipline are defined Red - Electrical, yellow - Mechanical, Black - process, Blue - Instrument, Green - Other.                                                                             

When more than one agency or involved in the job each authorized person must affix his on personal lock and tags before beginning any work.
LOTO lock and tags

Multi-lock devices shall be used as need for additional locks Tag-out devices.

Who it effected?

  • LOTO impacts life of worker and facility's.
  • Three categories to stake holders include.
  • Authorized employees who are specifically trend and perform and maintain LOTO.
  • Affects employees who work with or near the equipment being serviced who are trained to recognized LOTO but not perform for Lockout-Tagout activities.
Effective Energy Control                       
Let know about the four-key compartment to an effective energy control program LOTO produced   that outline specify step and requirement authorized employees need to complete safe lockout of the equipment. 
A periodic inspection should follow for check workman are follow loto procedure properly or not, review and update the same. Give the LOTO training to all employee and work man.



Main point for to apply LOTO                                                                                                            
  • Shutdown perpetration - Locate all power sources that power the device. Each source should is identified on the lockout process of the instrument. 
  • Notifications - Inform all affected employees and teams that you are ready to start the lockout process. 
  • Shutdown - Turn off the device by following its normal shutdown procedure and isolate and services line also. 
  • Isolation - Disconnect the equipment by turning off the energy at the main power source Apply a lockout device and tag — Apply the lock to each energy stripping device to a suitable lockout device, each lockout point that is detailed in the lockout process.
  • The lockout tag that goes with it should clearly indicate who applied the lockout device. 
  • If many people are going to work on one piece of equipment, each must apply their own lock to the isolation device. 
  • This will ensure that the energy source remains closed until each worker removes their own lock. 
  • Discarding or securing any stored energy - this may include draining valves, releasing hydraulic pressure, closing moving parts, or in the process. 
  • Verification - Turn off the power by attempting to restart the device after electrical isolation. Once verified, the equipment returns to the switch off position.

Tagout picture, (do not operate tag)


do not operate tag for loto 


    • All indication Gauges, transmitter, and indicators should be check before the LOTO removed from energy source to confirm is that work is completed or not. Drains can become blocked and not function properly as designed.
    • When verifying isolation, personnel must be taking precautions to avoid any other putting themselves at risk or creating additional hazards.

Step for LOTO before staring the job

    • To Start LOTO - know the type, amount, hazards and control methods of energy
    • Review the activity to be conducted for which LOTO is to be done
    • Review relevant standards and procedures
    • Secure relevant P&ID, plans, drawings, etc. As necessary
    • Prepare plan of action i.e., Work Clearance Document.

Step for Removing LOTO and Restoring Equipment

    • Safeguard employees, ensure all are clear of the equipment.
    • Alert employees on re-energization.
    • Verify all tools have been removed and all guards reinstalled.
    • Remove LOTO devices.
    • Energize equipment.
Safe Work Closure (before putting the equipment in normal operation).
    • Check if all the barricades, notices, etc. Are removed.
    • Check if all Permits to Work associated with the equipment are closed
    • Check if all lock-out devices are returned to their respective designated locations.
    • Observe for any abnormal sound, vibration, etc.

Monday, July 27, 2020

Rolling contact bearing part 2

Rolling contact bearing

Learning Objective of this chapter
  • Explained the different combination of bearing
  • Decrease the internal clearance and pre-load of bearing
  • Learn about bearing codes

Interview question on bearing

Combination of bearing use in equipment

Three type of combination of bearing mentioned below
  • O type of arrangement (DB) back to back
  • X type of arrangement (DF) face to face
  • Tendon arrangement

O type of arrangement (Back to Back)

The distance or (pressure point) between inner and outer cage is more because the smaller deformation occur due to moment loads this type of arrangement bearing can take large moment load than X type of arrangement.
Two angular contact ball bearing or two taper rollers bearing which take combine loads and can be paired in combination of X arrangement, O arrangement and tendon arrangements. O arrangement two bearing use for directional and axial load

X type of arrangement (Face to Face)

X type of arrangement use if the shaft going hot during the operation, to prevent bearing damaged from this pre-load given during mounting of bearing on shaft increases.
But in O type of arrangement the co-efficient of thermal expansion for bearing and other part will be same. Because the axial and radial thermal expansions cancel out each other, and in this condition given pre-load during installation does not change.

X type of arrangement bearing can tolerate the inaccuracy of housing and it can tolerate shaft deflection due to poor shaft rigidity.
Tandem arrangement use for heavy loads with low speeds.

What is cage bearing and full complement bearing?

full complement bearing

Full complement without cage bearing have a greater number of rolling elements. It can support very large loads. But mutual contact of rolling elements increases friction to each other. It is run at relatively low speed or to slewing motions.

Caged bearing

Caged bearing has smaller number of rolling elements. It can support less loads as compared to full complement bearing. But in caged bearing mutual contact of rolling elements have less friction to each other, rolling element are separate in it. It can run high at speeds.

Where full complement bearing are used?

High load with very low speed.

Types of Bearing internal clearance

Zero operational clearance and slight pre-load, some positive clearance, arrangement has some pre-load.

What happen if clearance is less than required in a spherical roller bearing after mounting on the shaft?

Bearing life reduced and creating noise during operation due to thermal expansion. What do you mean of bearing pre-load.

why it is important?
  • Enhance the bearing stiffness
  • Enhance the accuracy of shaft guidance
  • Compensate for wear and settling in operation
  • Give a long service life

Radial load

Cylindrical roller Double row angular contact Deep grove

List of Axial load bear bearing

Single row angular contact,  Taper roller bearing,  Deep groove.

Rolling contact bearing materials is that silicon Nitrite, 52100 steel, 440c stainless steel, m 50 steel.


Most of ball bearing are made of ?

A) 20MC5, B) SAE2100, C) Silicon Nitrite, D) 440c stainless steel.

axial and radial force

Code for bearing

Bearing code are combination of three term (letter and number), that is prefix, basic code, suffix.
There are 4 different prefixes use in bearing nomenclature,
R means ring of cylindrical or taper roller bearing with rolling element and cage but not separable ring.
WS means ring and ball of thrust ball bearing.
GS means housing washer of thrust ball bearing.
K means cage with rolling elements. Go for code of bearings.

E high capacity bearing,
UA, UO AND UL means universal design of single row angular contact ball bearing with closed axial preload, no clearance and light preload respectively.
ZR and 2ZR bearing with one or two shields.
RSR and 2RSR bearing with one or two shields,
J, Y, M, F, L, T and TV pressed steel, pressed brass, machined brass, machined light alloy and plastic cage.
K means bearing with taper bore, taper 1:12 ratio.
PN (PO), P6, P5, P4, P2 tolerance class.
C1, C2, CN(CN), C3, C4, C5 bearing clearance.

For know, about inside bore, multiply last two digit with 5, and if D = 10, 12, 15, 17 then code number will be 00, 01, 02, 03 respectively.
And if d is more then 480 mm then written directly on bearings.

Full bearing code description with example 22320K EJ W 33 C33 C3 Means spherical roller bearing, straight bore, clearance is more then normal clearance, bore diameter is 120 mm, machined brass cage, high capacity bearing.

Sunday, July 19, 2020

Interview question on bearing

Interview question on bearing

What is bearing and why is it used?

Bearing is machine element, it is use for reduce the friction between two part of the machine, it is also increase the reliability and availability of a machine, and use for increase the life of machine and reduce the down time. There are many factors considered during the selection of appropriate bearing for a machine.

What factors are considered during selection of the machine?

there are many factors needed to be considered during the selection of a bearing are that is mentioned below. Equipment speed, equipment operating load, shaft torque, temperature of services fluid, availability of lubrication system, viscosity of the services fluid, type of load to be act on the machine and others.

What is function of bearing?

The main function of bearing are reducing the friction, support the machine shaft, smooth operation, increase reliability and availability of the machine parts.

How many type of bearing?

Three are many types of bearing but mainly two types of bearing mentioned below.
  • Rolling element bearing

    1. Ball bearing

      1. Deep groove ball bearing
      2. Angular contact ball bearing
      3. Self-align ball bearing
    2. Roller bearing

      1. Taper roller bearing
      2. Cylindrical roller bearing
      3. Needle roller bearing
      4. Spherical roller bearing
  • Plane bearing

    1. Sleeve bearing
    2. Thrust bearing
    3. Flange bearing
    4. Mounted bearing
    5. Spherical bearing
types of bearing

For father classification follow the link basics of bearing

How to calculate bearing life?

The bearing life calculation is based on operating load, operating speed and operating hours. According to ISO 281 the basic bearing rating calculation formula mentioned below, whereas c= basic bearing dynamic rating, p= exponent for bearing life, 3 for ball bearing and, 10/3 for roller bearing, P= dynamic bearing load, L10= basic bearing life (at 90% reliability) millionth of revolution.

bearing life calculation

What is L 10 bearing life?

L 10 means basic bearing life (at required % load reliability) millionth of rotation.

Where are bearings use?

The bearings are used in (small, medium, and heavy) machinery like pump, compressor, turbine, automobile, electrical motor, agriculture machinery, stitching machine, and all types of rotating machinery.

What is the application of bearing?

There are many applications of bearing according to their function. These are mentioned below.
  • Agriculture machine
  • Automobile (heavy and light)
  • Aeroplane
  • Plant machinery like, pump, compressor, turbine, blower and other type of rotating equipment.
  • Power generation equipment and others.

How to select bearing?

For bearing selection there are many factors need to considered
  • Rpm of the equipment
  • Carrying load of the machine shaft
  • Difficulty of installation of bearing
  • Space required for installation
  • Angular and parallel misalignment tolerance
  • Rigidity of the shaft and bearing both
  • Torque generates during operation
  • Lubrication availability
  • Easy to installation and dismantle
  • Thrust generate during operating
  • Viscosity of the fluid

Which alloy metals used to make bearing?

There are many types of alloy used for make bearing like, bronze, aluminium, zinc, lid, tin, antimony and other types of white alloy. These types of alloy are also used for heavy load and high-speed application.

Which type of bearing is used for heavy load and high-speed application?

Ball bearings are used for high speed application and minor misalignment tolerance, due to its point contact configuration. But for more load or heavy-duty application use for roller bearing. During the selection of bearing mainly 3 factors needed to consider temperature, speed and load.

What is radial play in bearing?

The radial play means, balls clearance within the bearing both cages, it is indicated by C1 to C5. Where C1 is tightened and C5 is looser than C2 > C3 > C4 > C5.

How to select lubricant for bearing?

There are three factors that must be considered during selection of bearing that is temperature, speed, and loads carried by the shaft.

What type of bearing use in overhang centrifugal pump?

Mostly angular contact ball bearing and deep groove ball bearing are use in overhang centrifugal pump.