Vocational Training at IOCL, Panipat ( Mechanical Department) Report
SUMMER TRAINING REPORT
Indian Oil Corporation Ltd,Panipat
In partial fulfilment of requirements for the degree of
BACHELOR OF TECHNOLOGY
SWAMI KESHVANAND INSTITUTE OF TECHNOLOGY,
MANAGEMENT AND GRAMOTHAN
Ramnagaria, Jagatpura Jaipur-302 017, Rajasthan India
Dr. N.K. Banthiya
Industrial training plays a vital role in the progress of future engineers.
Not only does it provide insights about the industry concerned, it also
bridges the gap between theory and practical knowledge. I was fortunate
that I was provided with an opportunity of undergoing industrial training
at INDIAN OIL CORPORATION L TD. Panipat. The experience gained
during this short period was fascinating to say the least. It was a
tremendous feeling to observe the operation of different equipments and
processes. It was overwhelming for us to notice how such a big refinery is
being monitored and operated with proper coordination to obtain desired
results. During my training I realized that in order to be a successful
mechanical engineer one needs to possess a sound theoretical base along
with the acumen for effective practical application of the theory. Thus, I
hope that this industrial training serves as a stepping stone for me in
future and help me carve a niche for myself in this field.
My indebtedness and gratitude to the many individuals who have helped
to shape this report in its present form cannot be adequately conveyed in
just a few sentences. Yet I must record my immense gratitude to those
who helped me undergo this valuable learning experience at IOCL
I am highly obliged to Mr. Yogesh Joshi, Training and Development
Department for providing me this opportunity to learn at IOCL. I thank
Shri Anand Prakash, Chief Manager (Maintenance Department) for guiding
me through the whole training period. I express my heartiest thanks to
Shri Sirajuddin Ahmed, for sharing his deep knowledge about various
pumps and other equipments in workshop. I would also like to thank Mr.
Samir Das in valve section for explaining us about different valves and
their repairing. My special thanks to the SPM Instruments team for the on
field experience of vibration testing of equipments and Shri Sanjay Lamba
for showing us detailed procedure of analysis of vibrations.
I am grateful to Shri Sanjay Gathwal, Senior Mechanical Engineer for his
simple yet effective explanation of Panipat Refinery as a whole and
guiding us about various other aspects of career as a mechanical
Last but not the least I am thankful to Almighty God, my parents, family
and friends for their immense support and cooperation throughout the
Petroleum is derived from two words – “petro” means rock and
“oleum” means oil. Thus the word “petroleum” means rock oil. This is a
mixture of hydrocarbons; hence it cannot be used directly and has got
to be refined. Petroleum is refined in petroleum refinery.
Indian Oil Corporation Ltd. (IOC) is the flagship national oil company
in the downstream sector. The Indian Oil Group of companies owns
and operates 10 of India's 19 refineries with a combined refining
capacity of 1.2 million barrels per day. These include two refineries of
subsidiary Chennai Petroleum Corporation Ltd. (CPCL) and one of
Bongaigaon Refinery and Petrochemicals Limited (BRPL). The 10
refineries are located at Guwahati, Barauni, Koyali, Haldia, Mathura,
Digboi, Panipat, Chennai, Narimanam, and Bongaigaon.
Indian Oil's cross-country crude oil and product pipelines network span
over 9,300 km. It operates the largest and the widest network of
petrol & diesel stations in the country, numbering around 16455.
Indian Oil Corporation Ltd. (Indian Oil) was formed in 1964 through
the merger of Indian Oil Company Ltd and Indian Refineries Ltd. Indian
Refineries Ltd was formed in 1958, with Feroze Gandhi as Chairman
and Indian Oil Company Ltd. was established on 30th June 1959 with
Mr S. Nijalingappa as the first Chairman.
Panipat Refinery has doubled its refining capacity from 12 MMT/yr to 15
MMT/yr with the commissioning of its Expansion Project. Panipat Refinery
is the seventh refinery of Indian Oil. It is located in the historic district of
Panipat in the state of Haryana and is about 23 km from Panipat City. The
original refinery with 6 MMTPA capacity was built and commissioned in
1998 at a cost of Rs. 3868 crore (which includes Marketing Pipelines
The major secondary processing units of the Refinery include Catalytic
Reforming Unit, Once through Hydrocracker unit, Resid Fluidised Catalytic
Cracking unit, Visbreaker unit, Bitumen blowing unit, Sulphur block and
associated Auxiliary facilities. In order to improve diesel quality, a Diesel
Hydro Desulphurization Unit (DHDS) was subsequently commissioned in
Referred as one of India’s most modern refineries, Panipat Refinery was
built using global technologies from IFP France; Haldor-Topsoe, Denmark;
UNOCAL/UOP, USA; and Stone &Webster, USA. It processes a wide range
of both indigenous and imported grades of crude oil. It receives crude
from Vadinar through the 1370 km long Salaya-Mathura Pipeline which
also supplies crude to Koyali and Mathura Refineries of Indian Oil.
Petroleum products are transported through various modes like rail, road
as well as environment-friendly pipelines. The Refinery caters to the high-
consumption demand centers in North-Western India including the States
of Haryana, Punjab, J &K, Himachal, Chandigarh, Uttaranchal, as well as
parts of Rajasthan and Delhi.
A pump is a device that moves fluids or sometimes slurries by
mechanical action. Pumps can be classified into three major groups
according to the method they use to move the fluid: direct lift,
displacement, and gravity pumps.
Pumps operate via many energy sources and by some mechanism
(typically reciprocating or rotary), and consume energy to perform
mechanical work by moving the fluid by manual operation, electricity,
engine or wind power.
Common Pumps Used In IOCL
1. Centrifugal Pumps
A centrifugal pump is a pump that consists of a fixed impeller on a
rotating shaft that is enclosed in a casing, with an inlet and a discharge
connection. As the rotating impeller swirls the liquid around, centrifugal
force builds up enough pressure to force the water through the discharge
outlet. This type of pump operates on the basis of an energy transfer, and
has certain definite characteristics which make it unique. The amount of
energy which can be transferred to the liquid is limited by the type and
size of the impeller, the type of material being pumped, and the total
head of the system through which the liquid is moving.
Centrifugal pumps are designed to be used as a portable pump, and are
often referred to as a trash pump. It is named so because the water that
is being pumped is not clean water. It is most often water containing soap
or detergents, grease and oil, and also solids of various sizes that are
suspended in the water.
The major types of centrifugal pumps used in the refinery are:
1. Vertical Cantilever Pump
It is a specialized type of vertical sump pump designed to be
installed in a tank or sump but with no bearing located in the lower
part of the pump. Thus, the impeller is cantilevered from the motor,
rather than supported by the lower bearings.
A cantilever pump is considered a centrifugal pump configured with
the impeller submerged in the fluid to be pumped. But unlike a
traditional vertical column sump pump, there are no bearings below
the motor supporting the impeller and shaft.
The cantilever pump has a much larger diameter shaft, since it has
no lower sleeve bearings that act to support the impeller and shaft.
In general, cantilever pumps are best for relatively shallow sumps,
usually around 8 to 10 feet maximum. This is because the deeper
the sump, the larger the shaft diameter that is required to
cantilever the impeller.
2. Split Case Pumps
This type of pump has a split casing at the suction side. It prevents
the turbulence and formation of eddies at inlet.
Split Case pumps are designed to pump clean water or low viscosity
clean liquids at moderate heads more economically, which is widely
used for liquid transfer and circulation of clean or slightly polluted
water. And the typical applications are Municipal water supply,
Power plants, Industrial plants, Boiler feed and condensate systems,
Irrigation and dewatering and marine service.
Less noise and vibration, suitable to a lifting speed working
Inverted running is available for the same rotor, the risk of water
hammer is lower;
Unique design for high temperature application up to 200 ℃,
intermediate support, thicker pump casing, cooling seals oil
Vertical or horizontal with packing seal or mechanical seal can be
designed according to the different working condition;
Beautiful outline design.
Specifications of a Centrifugal Pump in Refinery
Offered Capacity: 317 LPM
Sealing: Mechanical Seal
Power Rated: 7 KW
Applications of Centrifugal Pump in Panipat
For circulation of cooling water
For pump the fluid (crude oil, VGO, diesel etc.) in reactors,
coulombs etc. with high pressure.
In liquid storage tanks
Net Positive Suction Head (NPSH) Overview
Net Positive Suction Head (NPSH) NPSH Available is a function of the
system in which the pump operates. It is the excess pressure of the liquid
in feet absolute over its vapor pressure as it arrives at the pump suction.
In an existing system, the NPSH Available can be determined by a gauge
on the pump suction.
The Hydraulic Institute defines NPSH as the total suction head in feet
absolute, determined at the suction nozzle and corrected to datum, less
the vapor pressure of the liquid in feet absolute. Simply stated, it is an
analysis of energy conditions on the suction side of a pump to determine
if the liquid will vaporize at the lowest pressure point in the pump.
The pressure which a liquid exerts on its surroundings is dependent upon
its temperature. This pressure, called vapor pressure, is a unique
characteristic of every fluid and increased with increasing temperature.
When the vapor pressure within the fluid reaches the pressure of the
surrounding medium, the fluid begins to vaporize or boil. The temperature
at which this vaporization occurs will decrease as the pressure of the
surrounding medium decreases.
A liquid increases greatly in volume when it vaporizes. One cubic foot of
water at room temperature becomes 1700 cu. ft. of vapor at the same
It is obvious from the above that if we are to pump a fluid effectively, we
must keep it in liquid form. NPSH is simply a measure of the amount of
suction head present to prevent this vaporization at the lowest pressure
point in the pump.
NPSH can be defined as two parts:
NPSH Available (NPSHA): The absolute pressure at the
suction port of the pump.
NPSH Required (NPSHR): The minimum pressure required at
the suction port of the pump to keep the pump from cavitating.
NPSHA is a function of your system and must be calculated, whereas
NPSHR is a function of the pump and must be provided by the pump
manufacturer. NPSHA must be greater than NPSHR for the pump system
to operate without cavitating. Thus, we must have more suction side
pressure available than the pump requires.
Cavitation is a term used to describe the phenomenon, which occurs in a
pump when there is insufficient NPSH Available. When the pressure of the
liquid is reduced to a value equal to or below its vapor pressure the liquid
begins to boil and small vapor bubbles or pockets begin to form. As these
vapor bubbles move along the impeller vanes to a higher pressure area
above the vapor pressure, they rapidly collapse.
The collapse or "implosion" is so rapid that it may be heard as a rumbling
noise, as if you were pumping gravel. In high suction energy pumps, the
collapses are generally high enough to cause minute pockets of fatigue
failure on the impeller vane surfaces. This action may be progressive, and
under severe (very high suction energy) conditions can cause serious
pitting damage to the impeller.
Cavitation is often characterized by:
Loud noise often described as a grinding or “marbles” in the pump
Loss of capacity (bubbles are now taking up space where liquid
Pitting damage to parts as material is removed by the collapsing
Vibration and mechanical damage such as bearing failure
Erratic power consumption
The way to prevent the undesirable effects of cavitation in standard low
suction energy pumps is to insure that the NPSH Available in the system
is greater than the NPSH required by the pump.
2. Screw Pumps
Main Elements of Screw Pump Design
The pumping element of a two screw pump consists of two intermeshing
screws rotating within a stationary bore/housing that is shaped like a
The rotor and housing/body are metal and the pumping element is
supported by the bearings in this design.
The clearances between the individual areas of the pumping screws are
maintained by the timing gears.
When a two screw pump is properly timed and assembled there is no
metal-to-metal contact within the pump screws.
The pumping screws and body/ housing can be made from virtually any
machinable alloy. This allows the pump to be applied for the most severe
applications in aggressive fluid handling. Hard coatings can also be
applied for wear resistance.
The stages of the screw are sealed by the thin film of fluid that moves
through the clearances separating them.
Finally, in a two screw design, the bearings are completely outside of the
pumped fluid. This allows them to have a supply of clean lubricating oil
and be independent of the pumped fluid characteristics. The external
housings also allows for cooling which means the quality of the lube oil
can be maintained in high temperature or horsepower applications.
These pumps are based on the basic principle where a rotating cavity or
chamber within a close fitting housing is filled with process fluid, the
cavity or chamber closes due to the rotary action of the pump shaft(s),
the fluid is transported to the discharge and displaced, this action being
accomplished without the need for inlet or outlet check valves.
Specifications of a Screw Pump
Name: Emergency Lube Oil Pump
Driver: Electric Motor
Liquid Handled: Lube Oil
Pumping temperature: 65o
Specific Gravity: 0.88
Rated Capacity: 237 LPM
Suction Pressure: Atmospheric
Discharge Pressure: 10 Kg/cm2
NPSH available: 10 m
Mostly used for high viscous fluid.
Used where high pressure is needed.
Pump Selection on basis of Process Parameters
Selecting between a Centrifugal Pump or a Positive Displacement Pump is
not always straight forward. Following factors are considered while
selecting a pump:
1.Flow Rate and Pressure Head
The two types of pumps behave very differently regarding pressure
head and flow rate:
The Centrifugal Pump has varying flow depending on the system
pressure or head.
The Positive Displacement Pump has more or less a constant flow
regardless of the system pressure or head. Positive Displacement
pumps generally give more pressure than Centrifugal Pumps.
2.Flow and Viscosity
In the Centrifugal Pump the flow is reduced when the viscosity is
In the Positive Displacement Pump the flow is increased when
viscosity is increased.
Liquids with high viscosity fill the clearances of a Positive
Displacement Pump causing a higher volumetric efficiency and a
Positive Displacement Pump is better suited for high viscosity
applications. A Centrifugal Pump becomes very inefficient at even
3.Mechanical Efficiency and Pressure
Changing the system pressure or head has little or no effect on the flow
rate in the Positive Displacement Pump.
Changing the system pressure or head has a dramatic effect on the flow
rate in the Centrifugal Pump.
4.Mechanical Efficiency and Viscosity
Viscosity also plays an important role in pump mechanical
efficiency. Because the centrifugal pump operates at motor speed
efficiency goes down as viscosity increases due to increased
frictional losses within the pump. Efficiency often increases in a PD
pump with increasing viscosity. Note how rapidly efficiency drops off
for the centrifugal pump as viscosity increases.
5.Net Positive Suction Head – NPSH
In a Centrifugal Pump, NPSH varies as a function of flow determined
In a Positive Displacement Pump, NPSH varies as a function of flow
determined by speed. Reducing the speed of the Positive
Displacement Pump, reduces the NPSH.
Common Problems encountered in Pumps
The types of pumps that are most commonly used in a Refinery
plant are centrifugal pumps. These pumps use centrifugal action to
convert mechanical energy into pressure in a flowing liquid. The
main components of the pump that are usually prone to problems
shafts, seals and bearings.
An important aspect of the impeller is the wear rings. If the impeller
is too close to the stationary element, the impeller or the casing will
be worn out. The other part is the shaft. It runs through the center
of the pump and is connected to the impeller at the left end.
Seal is a very important part in the pump. Seals are required in the
casing area where the liquid under pressure enters the casing.
The last main part of the pump is the bearing. The pump housing
contains two sets of bearings that support the weight of the shaft.
The failures causing the stoppage of the pumps are primarily
experienced by these parts and will be termed as failure modes.
There are 12 major failure modes (bad actors) for the most
pumps. The following is the definition adopted to characterize the
various modes of failure:
♦Shaft: The pump failed to operate because of shaft problem, such
as misalignment, vibration, etc.
♦Suction Valve: A failure due to something wrong with the pump
suction, such as problems in valve, corroded pipes or slug
accumulated in the suction.
♦Casing: A failure due to defective casing, such as misalignment or
♦Operation Upset Failure of a pump due to operational mistakes,
such as closing
a valve which should not be closed.
♦Coupling A failure due to coupling distortion or misalignment.
♦Gaskets A failure due to a gasket rupture or damage caused by
♦Control Valve A failure due to malfunction of the control valve due to
pressure or flow in the line of service.
FUNDAMENTALS OF VIBRATION
Most of us are familiar with vibration; a vibrating object moves to and fro,
back and forth. A vibrating object oscillates. We experience many
examples of vibration in our daily lives. A pendulum set in motion
vibrates. A plucked guitar string vibrates. Vehicles driven on rough terrain
vibrate, and geological activity can cause massive vibrations in the form
In industrial plants there is the kind of vibration we are concerned about:
Machine vibration is simply the back and forth movement of
machines or machine components. Any component that moves back
and forth or oscillates is vibrating
Machine vibration can take various forms. A machine component
may vibrate over large or small distances, quickly or slowly, and
with or without perceptible sound or heat. Machine vibration can
often be intentionally designed and so have a functional purpose.
(Not all kinds of machine vibration are undesirable. For example,
vibratory feeders, conveyors, hoppers, sieves, surface finishers and
compactors are often used in industry.)
Almost all machine vibration is due to one or more of these
(a) Repeating forces (b) Looseness (c) Resonance
(a) Repeating Forces
Repeating forces in machines are mostly due to the rotation of
imbalanced, misaligned, worn, or improperly driven machine components.
Worn machine components exert a repeating force on machine
components due to rubbing of uneven worn parts. Wear in roller bearings,
gears and belts is often due to improper mounting, poor lubrication,
manufacturing defects and over loading.
Improperly driven machine components exert repeating forces on
machine due to intermittent power supply. Examples include pump
receiving air in pulses, IC engines with misfiring cylinders, and
intermittent brush commutator contact in DC Motors.
Looseness of machine parts causes a machine to vibrate. If parts
become loose, vibration that is normally of tolerable levels may
become unrestrained and excessive.
Looseness can cause vibrations in both rotating and non rotating
Looseness can be caused by excessive bearing clearances, loose
mounting bolts, mismatched parts, corrosion and cracked
Machines tend to vibrate at certain oscillation rates. The oscillation
rate at which a machine tends to vibrate is called its natural
oscillation rate. The natural oscillation rate of a machine is the
vibration rate most natural to the machine, that is, the rate at
which the machine 'prefers' to vibrate.
if a machine is 'pushed' by a repeating force with a rhythm
matching the natural oscillation rate of the machine? The machine
will vibrate more and more strongly due to the repeating force
encouraging the machine to vibrate at a rate it is most natural with.
The machine will vibrate vigorously and excessively, not only
because it is doing so at a rate it 'prefers' but also because it is
receiving external aid to do so. A machine vibrating in such a
manner is said to be experiencing resonance. A repeating force
causing resonance may be small and may originate from the motion
of a good machine component. Such a mild repeating force would
not be a problem until it begins to cause resonance. Resonance,
however, should always be avoided as it causes rapid and severe
Why Monitor Machine Vibration?
Monitoring the vibration characteristics of a machine gives us an
understanding of the 'health' condition of the machine. We can use
this information to detect problems that might be developing.
If we regularly monitor the conditions of machines we will find any
problems that might be developing, therefore we can correct the
problems even as they arise. In contrast, if we do not monitor
machines to detect unwanted vibration the machines are more likely
to be operated until they break down.
Below we discuss some common problems that can be avoided by
monitoring machine vibration
(a) Severe Machine Damage
(b) High Power Consumption
(c) Machine Unavailability
(d) Delayed Shipments
(e) Accumulation of Unfinished Goods
f) Unnecessary Maintenance
(g) Quality Problems
h) Bad Company Image
(i) Occupational Hazards
Types of Vibration Monitoring Parameters
Vibration amplitude may be measured as a displacement, a velocity, or
acceleration. Vibration amplitude measurements may either be relative,
or absolute. An absolute vibration measurement is one that is relative to
free space. Absolute vibration measurements are made with seismic
Displacement measurement is the distance or amplitude displaced from a
resting position. The SI unit for distance is the meter (m), although
common industrial standards include mm and mils. Displacement
vibration measurements are generally made using displacement eddy
Velocity is the rate of change of displacement with respect to change in
time. The SI unit for velocity is meters per second (m/s), although
common industrial standards include mm/s and inches/s. Velocity
vibration measurements are generally made using either swing coil
velocity transducers or acceleration transducers with either an internal or
external integration circuit.
Acceleration is the rate of change of velocity with respect to change in
time. The SI unit for acceleration is meters per second2 (m/s2), although
the common industrial standard is the g. Acceleration vibration
measurements are generally made using accelerometers.
Vibration Monitoring Sensors & Selections
Sensors & Sensor Selection:
In industry where rotating machinery is everywhere, the sounds made by
engines and compressors give operating and maintenance personnel first
level indications that things are OK. But that first level of just listening or
thumping and listening is not enough for the necessary predictive
maintenance used for equipment costing into the millions of dollars or
supporting the operation of a production facility.
The second layer of vibration analysis provides predictive information on
the existing condition of the machinery, what problems may be
developing, exactly what parts may be on the way to failure, and when
that failure is likely to occur. Now, you may schedule repairs and have the
necessary parts on hand. This predictive maintenance saves money in
faster, scheduled repairs and prevents failures that are much more
expensive in terms of repairs or lost production.
Application of these vibration sensors, with their associated
equipment, provides effective reduction in overall operating
costs of many industrial plants. The damage to machinery the
vibration analysis equipment prevents is much more costly than the
equipment and the lost production costs can greatly overshadow the
cost of equipment and testing.
Predicting problems and serious damage before they occur offers a
tremendous advantage over not having or not using vibration
Specific areas of application include any rotating machinery such as
motors, pumps, turbines, bearings, fans, and gears along
with their balancing, broken or bent parts, and shaft
The vibration systems find application now in large systems such
as aircraft, automobile, and locomotives while they are in
Dynamic fluid flow systems such as pipelines, boilers, heat
exchangers, and even nuclear reactors use vibration analysis to find
and interpret internal problems.
What is a valve?
A valve is a mechanical device which regulates either the flow or the
pressure of the fluid. Its function can be stopping or starting the flow,
controlling flow rate, diverting flow, preventing back flow, controlling
pressure, or relieving pressure.
Basically, the valve is an assembly of a body with connection to the pipe
and some elements with a sealing functionality that are operated by an
actuator. The valve can be also complemented whit several devices such
as position testers, transducers, pressure regulators, etc.
Common Valves Used In PANIPAT REFINERY
Application In Refinery
Gate valves have an extended use in the petrochemical industry
due to the fact that they can work with metal-metal sealing.
They are used in clean flows.
When the valve is fully opened, the free valve area coincides with
area of the pipe, therefore the head lose of the valve is small.
This valve is not recommended to regulate or throttling service
since the closure member could be eroded. Partially opened the
valve can vibrate.
Opening and closing operations are slow. Due to the high friction
wear their use is not recommend their use in often required
This valve requires big actuators which have difficult automation.
They are not easy to repair on site.
The ball valve has a spherical plug as a closure member. Seal on ball
valves is excellent, the ball contact circumferentially uniform the seat,
which is usually made of soft materials
Depending on the type of body the ball valve can be more or less easily
maintained. Drop pressure relative its hole size is low.
Application in Refinery
They are used in steam, water, oil, gas, air, corrosive fluids, and can also
handle slurries and dusty dry fluids. Abrasive and fibrous materials can
damage the seats and the ball surface.
The seat material resistance of the ball valve limits the working
temperature and pressure of the valve. The seat is plastic or metal
Ball valves are mostly used in shutoff applications. They are not
recommended to be used in a partially open position for a long time
under conditions of a high pressure drop across the valve, thus the
soft seat could tend to flow through the orifice and block the valve
The development of this type of valve has been more recent than
other ones. A major conviction on saving energy in the installations
was an advantage for its introduction, due its head loss is small. At
the beginning they were used in low pressure installations service,
but technologic improvements, especially in the elastomer field let
their extension to higher performances.
As any quarter turn valve, the operative of the butterfly valve is
quiet easy. The closure member is a disc that turns only 90º; to be
This is a quick operation.
Few wear of the shaft, little friction and then less torque
needed means a cheaper actuator. The actuator can be manual,
oleo hydraulic or electrical motorized, with automation available.
Butterfly valves geometry is simple, compact and revolute,
therefore it is a cheap valve to manufacture either saving material
and post mechanization.
Its reduced volume makes easy its installation. Gate and globe
valves are heavier and more complex geometry, therefore butterfly
valve can result quiet attractive at big sizes regarding other types of
Application in Refinery
Butterfly valves are quite versatile ones. They can be used at
multiples industrial applications, fluid, sizes, pressures,
temperatures and connections at a relative low cost.
Butterfly valves can work with any kind of fluid, gas, liquid and also
with solids in suspension. As a difference from gate, globe or ball
valves, there are not cavities where solid can be deposit and
difficult the valve operative.
Pressure and temperature are determinant and correlated designing
factors. At a constant pressure, rising temperature means a lower
performance for the valve, since some materials have lower capacity. As
well gate, globe and ball valves, the butterfly valve can be manufactured
with metallic seats that can perform at high pressure and extreme
Plug valves have a plug as a closure member. Plug can be
cylindrical or conical. Ball valves are considered as another group
despite that they are some kind of plug valve.
Plug valves are used in On/Off services and flow diverting, as they
can be multiport configured.
They can hand fluids with solids in suspension.
Lift plug valve type are designed to rise the plug at start valve
operation, in order to separate and protect plug-seat sealing
surfaces from abrasion
It require high maintenance cost
Require more time for maintenance
A Globe valve may be constructed with a single or double port and plug
arrangement. The double port type is generally used in a CONTROL VALVE
where accurate control of fluid is required. Due to the double valve plug
arrangement, the internal pressure acts on each plug in opposition to
each other, giving an internal pressure balance across the plugs.
This gives a much smoother operation of the valve and better
control of the process. Some control valves are 'Reverse Acting'.
Where a valve normally opens when the plug rises, in the reverse
acting valve, the valve closes on rising. The operation of the valve
depends on process requirements. Also depending on requirements,
a control valve may be set to open or close, on air failure to the
The Globe valve is used where control of fluid flow or pressure is
required and it can be operated in any position between open and
6.Non Returning Valve
A check valve may be defined simply as a mechanical device typically
used to let fluid, either in liquid or gas form, to flow through in one
direction. They usually have two ports or two openings – one for the fluid
entry and the other for passing through it. Often part of household items,
they are generally small, simple, and inexpensive components.
Operational Principal of Check Valve
Check valves are available with different spring rates to give particular
cracking pressures. The cracking pressure is that at which the check valve
just opens. If a specific cracking pressure is essential to the functioning of
a circuit, it is usual to show a spring on the check valve symbol. The
pressure drop over the check valve depends upon the flow rate; the
higher the flow rate, the further the ball or poppet has to move off its
seat and so the
There are two main types of check valve :
1. The 'LIFT' type. (Spring loaded 'BALL' & 'PISTON' Types).
2. The 'SWING' (or Flapper Type).
A safety valve is a valve mechanism which automatically releases a
substance from a boiler, pressure vessel, or other system, when the
pressure or temperature exceeds preset limits.
It is one of a set of pressure safety valves (PSV) or pressure relief
valves (PRV), which also includes relief valves, safety relief valves, pilot-
operated relief valves, low pressure safety valves, and vacuum pressure
PRESSURE SAFETY VALVE OR RELIEF VALVE:
The relief valve (RV) is a type of valve used to control or limit
the pressure in a system or vessel which can build up by a process upset,
instrument or equipment failure, or fire.
Schematic diagram of a
pressure relief valve.
The pressure is relieved by allowing the pressurized fluid to flow from an
auxiliary passage out of the system. The relief valve is designed or set to
open at a predetermined set pressure to protect pressure vessels and
other equipment from being subjected to pressures that exceed their
design limits. When the set pressure is exceeded, the relief valve
becomes the "path of least resistance" as the valve is forced open and
a portion of the fluid is diverted through the auxiliary route. The diverted
fluid (liquid, gas or liquid–gas mixture) is usually routed through
a piping system known as a flare header or relief header to a central,
elevated flare where it is usually burned and the
resulting combustion gases are released to the atmosphere
It should be noted that PRVs and PSVs are not the same thing, despite
what many people think; the difference is that PSVs have a manual lever
to open the valve in case of emergency.
TEMPERATURE SAFETY VALVE:
Water heaters have thermostatically controlled devices that keep them
Both gas and electric water heaters have temperature-limiting devices
that shut off the energy source when their regular thermostat fails
Thermostatically controlled gas valves found on most residential gas
water heaters have a safety shutoff built into the gas valve itself. When
they react to excessive temperature, the gas flow to the burner is
PROTECTION USED IN INDUSTRY:
The two general types of protection encountered in industry are thermal
protection and flow protection.
For liquid-packed vessels, thermal relief valves are generally
characterized by the relatively small size of the valve necessary to provide
protection from excess pressure caused by thermal expansion. In this
case a small valve is adequate because most liquids are nearly
incompressible, and so a relatively small amount of fluid discharged
through the relief valve will produce a substantial reduction in pressure.
Flow protection is characterized by safety valves that are considerably
larger than those mounted for thermal protection. They are generally
sized for use in situations where significant quantities of gas or high
volumes of liquid must be quickly discharged in order to protect the
integrity of the vessel or pipeline. This protection can alternatively be
achieved by installing a high integrity pressure protection
1. Vacuum safety valves (or combined pressure/vacuum safety valves)
are used to prevent a tank from collapsing while it is being emptied, or
when cold rinse water is used after hot CIP (clean-in-place) or SIP
2. Safety valves also evolved to protect equipment such as pressure
vessels (fired or not) and heat exchangers.
3. The term safety valve should be limited to compressible fluid
applications (gas, vapor, or steam).
4. Many fire engines have such relief valves to prevent the over
pressurization of fire hoses.
Valve Type Application Other information
Ball Flow is on or off Easy to clean
Butterfly Good flow control at high capacities Economical
Globe Good flow control Difficult to clean
Plug Extreme on/off situations More rugged, costly than ball valve
For any academic discipline, especially practical streams like engineering
field knowledge should go hand in hand with theoretical knowledge. In
university classes our quest for knowledge is satisfied theoretically.
Exposure to real field knowledge is obtained during such vocational
training. We have learnt a lot about pumps, safety valves, flow control
valves, compressors, machine vibrations and their analysis and many
more things of working in an industry. We might have thoroughly learnt
the theory behind these but practical knowledge about these were mostly
limited to samples at laboratory. At IOCL we actually saw the equipments
used in industry. Though the underlying principle remains same but there
are differences as far as practical designs are considered.
We also got to know additionally about other features not taught or
known earlier. This has helped to clarify our theoretical knowledge a lot.
Apart from knowing about matters restricted to our own discipline we also
got to know some other things about the processing of crude and
manufacturing of various petrochemical products and fuels which we
might not have necessarily read within our curriculum. Such vocational
trainings, apart from boosting our knowledge give us some practical
insight into corporate sector and a feeling about the industry
environment. The close interactions with guides, many of whom are just
some years seniors to us have also helped us a lot. It is they who, apart
from throwing light on equipments, have also shown the different aspects
and constraints of corporate life. Discussions with them have not only
satisfied our enquiries about machines and processes but also enlightened
about many other extracurricular concepts which are also important. Thus
our training in IOCL has been a truly enlightening learning experience.