The document discusses marine air compressors used on ships. It describes the various uses of compressed air on ships, including starting main/auxiliary engines, automation/control, pneumatic tools, fog horns, and more. It provides details on compressor requirements, operating principles, intercooling benefits, maintenance procedures, and common issues like low efficiency.
The gas turbine is an internal combustion engine that uses air as the working fluid. The engine extracts chemical energy from fuel and converts it to mechanical energy using the gaseous energy of the working fluid (air) to drive the engine and propeller, which, in turn, propel the aeroplane.
The gas turbine is an internal combustion engine that uses air as the working fluid. The engine extracts chemical energy from fuel and converts it to mechanical energy using the gaseous energy of the working fluid (air) to drive the engine and propeller, which, in turn, propel the aeroplane.
100++-interview questions and answers on steam turbine.pdfmaheshwali1
100++-interview questions and answers on steam turbine
Is it possible to have a negative absolute pressure?
No, absolute pressure is measured with reference to a perfect vacuum so it is impossible for it to go negative. You can only measure negative pressure between two different pressures. For example if you allow atmospheric air to gradually flow into a vacuum vessel and measure pressure inside relative to outside it will show a negative pressure reading.
What type of problems do you face in steam turbines related to vacuum?
Problems such as:
· Low vacuum
· High exhaust pressure
· High exhaust temperature
· Higher specific steam consumption
· More cooling water circulation
· Hot well level variation
How do you create vacuum in steam condensers?
Vacuum is created in condenser by steam jet ejectors, where high pressure 8–12 kg/cm2 steam is passed through nozzle which is connected to air line from condenser. This creates high negative pressure there by evacuating air from condenser.
Generally there are Two Types of Ejectors:
Hogger Ejector: Initially this ejector is used for pulling vacuum. It has steam and air lines connections, steam is vented directly into atmosphere. It consumes more steam than main ejectors. It requires 20–30 minutes to create 85% of operating vacuum.
Main Ejector: It comes with first stage and second stage. Air line from surface condenser is given to 1st stage then again air from 1st stage is collected and discharged into 2nd stage. 2nd stage ejector has air vent line.
It consumes less steam than hogger ejector. Generally an ejector come with 1W + 1S i.e. one working and one stand by.
Also vacuum pumps called liquid ring vacuum pumps are used to create vacuum in condensers. Which consume less energy than steam jet air ejector
How does low vacuum affect on turbine speed?
Lower vacuum creates back pressure on turbine blades and rotors. So in emergency, vacuum breaker valve is opened to bring down the turbine speed to zero in minimum time to avoid any further damages.
What is the effect of low vacuum & high exhaust pressure on steam turbine performance?
Low vacuum or high exhaust pressure & high exhaust temperatures lead to more steam consumption to generate unit power.
What are the potential reasons for lower vacuum in steam condenser?
· More condenser load than design
· Lesser amount of cooling water circulation in condenser
· Higher atmosphere temperature
· Location of the steam condenser at higher elevations.
· More exhaust temperature
· Air leakages in the system
· Lesser efficiency of steam ejector or vacuum pump
· Ejector inter condense (1st stage) condensate seal break
· Lesser pressure & temperature of motive steam at ejector inlet
· Worn out ejector nozzles
· Improper quality of motive steam
· Variation in condenser inlet & outlet cooling water temperatures
· Operation of Turbine at lower load
· Lower gland seal steam pressure
What are the effects of air le
Classification of Pneumatic Elements Included Valves, CompressorMohammad Azam Khan
Pneumatic systems range from simple air-driven pistons to multiple-actuator mining operations. All pneumatic systems use a source of compressed air to power moving parts, or actuators. Pneumatic systems commonly use compressed atmospheric air, as it is abundant and inexpensive. Atomized oil is added to the air in some blends to ease its passage through mechanical systems. Pneumatic systems are generally preferred over similar, liquid-using hydraulic systems, due to their quietness, ease of use and cost efficiency.
This slide is about some new methods of compressing system. There is a huge use of reciprocating air compressor, but Rotary and liquid rim compressors are new with more efficiency.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
2. Marine air compressor is important auxiliary machinery
on ships It is used for producing compressed air, which
has a number of applications on board, both in the
engine and deck department.
Uses of compressed air on ship
30 bar for starting of main engine and auxiliary engine.
7 bar for automation and control air for main and
auxiliary engine.
For chipping, buffing, pressurized water jet cleaning,
pneumatic tools, pneumatic pumps like Weldon pumps.
Ships whistle and fog horn.
For supplying water through hydrophore.
For soot blowing of boiler and economizer.
For general cleaning and services 2
3. Two starting compressor must be fitted ,of
sufficient total capacity to meet the engine
requirements.
Each compressor must be able to press up air
receiver from 15 bar to 25 bar in 30 minutes.
If the emergency generator is arranged for
pneumatic starting, the air supply shall be from a
separate air receiver.
Total air receiver capacity must be sufficient for 12
starts for reversible engine and 6 starts or non-
reversible engines.
3
5. Air is drawn through the air inlet filter and suction valve
into the first stage cylinder on each downwards stroke of
the piston.
As the piston commences it’s upwards stroke, the spring
plates close the suction valve and the air is compressed in
the cylinder until the required pressure is reached.
At this pressure, the first stage delivery valve opens and the
compressed air is delivered to the first stage cooler.
It passes through the cooler to the outlet cover and then
into the second stage cylinder through the second stage
suction valve.
After compression, the air passes through the delivery valve
into the after cooler to the receiver.
5
6. Volumetric efficiency
It is the ratio of the volume of air taken in during each stroke to the swept volume
of the cylinder.
A loss in the volumetric efficiency of the compressor can be due to the poor valve
condition, dirty intake filter , increased bumping clearance , discharge line
blocked ,or restrictions in the intercooler
intercooler between stages.
6
6
7. 1-The work done in compressing the air is
reduced, thus power can be saved.
2-Prevents mechanical problems as the air
temperature is controlled.
3-The suction and delivery valves remain in
cleaner condition as the temperature and
vaporization of lubricating oil is less .
4-The machine is smaller and better balanced.
5-Effects from moisture can be handled better,
by draining at each stage .
7
8. Reduced air temperature, volume and increased air density for next
stage
So increased volumetric efficiency and compressor efficiency.
Due to reduced temperature give better lubrication for cylinder and
piston rings
Drain are fitted from which water and excessive oil can be drained out,
to prevent air bottle corrosion and starting air explosion and fouling of
inter coolers and pipe.
Save the work done.
Advantages of inter cooling of air compressor
To avoid excessive temperature rise associated with higher compression
ratios, and to approach isothermal compression.
Saving in power.
Volumetric efficiency is increased.
Reduced the volume of air delivered and also reduced the compressor
size.
It can reduce the air temperature.
Due to less temperature suction & delivery valves remain cleaner without
being fouled with carbonized oil.
It can avoid a danger of an explosion takes place in compressor cylinder.
It allows good lubrication of the compressor piston.
Moisture separation is easier through inter cooler drains.
8
9. To reduce final discharge air temperature thus air bottle size can be
reduced.
To reduce air volume after it has been compressed to the final
pressure.
So greater amount of air could be stored in air bottle.
Increase volumetric efficiency
Type of intercooler and after cooler
Intercooler is single pass type
After cooler is double pass U-tube type
Normal parameters of air compressor
LP discharge pressure: 4 bars
HP discharge pressure: 30 bars.
Intercooler inlet air temperature: 130 ° C
Intercooler outlet air temperature: 35 ° C
After cooler inlet air temperature: 130 ° C
After cooler outlet air temperature: 35 ° C
9
10. Change the switch to manual position on the switch
board.
Check the L.O sump level and condition.
Open the moisture drain valve.
Open the compressor discharge valve & charging valve
of air bottle.
Open cooling water system valves.
Turn the compressor flywheel by hand (one turn).
Start the motor, after draining the moisture shut the
drain valve.
Check the motor ampere consumed.
Check the pressure gauge readings.
Frequently drain the moisture.
When charging full, open drain valve and stop the
compressor
10
11. It is the clearance given to avoid the chance of mechanical
bumping of the piston and the cylinder head cover.
It is the distance between the top of the piston and the
cylinder cover when the piston is at Tdc.
It is approximately between the 0.5 % to 1% of the cylinder
bore.
It is checked by placing lead metal ball on the top of the
piston and then turning the compressor manually and then
take it out and measurment is done by vernier.
It can be adjusted by placing the gasket between the cylinder
block and cylinder head cover .we can also adjust it by adding
the shims under the connecting road.
11
11
12. Checked by filling time with the previous record and also check
the first stage discharge pressure.
If compressor efficiency is lower, compressor will run longer and
compressor temperature will rise.
First stage and second stage pressure gauge must be correct and
stable.
No escape of air from suction filter.
Intercooler and after cooler outlet air temperature should not be
high.
If open drain valve nothing can be found.
Low L.O consumption.
Oily air mixture must not blow out from breather pipe 12
13. Relief valve
- Normally fitted at discharge side of 1st stage
intercooler and 2nd stage after cooler.
- Each valve operate at 10% above stage working
Pressure.
Bursting disc
It is fitted on each cooler shell of air compressor,
relief of pressure when cooler tubes burst.
13
14. Fusible plug on the discharge side of the
compressor (above 105˚)
Lube oil low pressure alarm and trip.
Water high temperature alarm and trip.
Water no-flow trip.
Motor overload trip.
Delivery air temperature high max 93˚C
Drain valve at each coolers / unloader.
Non return valve at delivery side.
14
15. All the compressors need to be unloaded during starting ,stopping and
the regular intervals.
why unloading at starting
During the starting of a motor the starting current is very high , so to
avoid further overloading of the motor the compressor is started
unloaded
why at regular intervals
Intermittently the compressor is unloaded to remove the condensed
water inside which could go outside with the air
why at stopping
At stopping the same is done so as to drain all the moisture inside an in
preparation fort next starting.
Unloader (Magnetic valve)
Normally, an electrical timer relay mechanism is applied for no load
start of the compressor, when the compressor starts ,the timer function
to open the unloader (magnetic valve) to enter no load state (unloading)
approximate 5-10 seconds ,the magnetic valve closed and pressure rise
operation starts.
15
17. First of all make sure all the spare including
critical spares are available onboard before
commencing the work.
Be sure to disconnect both main power supply
and operating power supply during
maintenance.
Putting up sign boards
Before maintenance discharge the compressed
air from their receiver tank and make sure no
pressure is left in the compressor.
Crankcase oil and jacket water is drained
completely.
Opened up the cylinder head bolts and take
out the first stage valve assembly.
17
18. Remove the bottom end bolts and take out the
piston, remove the circlip to take out the gudgeon
pin out .
Remove the top end bearing and piston rings from
the piston.
All the part like piston rings ,piston outer diameter
, groove width should be calibrated .
Cylinder liner should be calibrated with bore gauge
Crankpin diameter should be measure with
micrometer at two places forward aft and port
starboard .
Sump oil should be renewed.
Suction and discharge valve should be lapped for
proper sealing. 18
19. Piston rings must be renewed if necessary.
Renew lube oil filter and suction filter.
Checking the bumping clearance by putting the lead ball
on the top of the piston.
Refill crankcase with new lube oil .
Turn the compressor by putting the bar in the flywheel to
check the free movement of the reciprocating parts.
After open the water to detect any leakages .
Manually open the drain valve to run the compressor
initially for just few second ,check the motor amperes.
Keep close eye on pressure gauge that how much time is
taken to press up the bottle till 25 bar.
All records of clearances must be kept with in and send
to the company.
19