Tuesday 21 January 2020

What chemical is used in chilled water?

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What chemical is used in chilled water?



Chiller chemicals are used to control corrosion and to prevent bacteria growth. The most common chiller corrosion chemical is a closed loop nitrite, borate, silicate product. The second chemical is a cooling water biocide. The most common biocide used to control bacteria is gluteraldehyde and isothiazolin. If freezing is a concern, you may consider using a propylene glycol solution such as Dowfrost.

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How do I feed my chiller chemicals?



If you can not manually dump the chemicals into a basin, chiller chemicals are either injected into the water system with a metering pump through an injector quill or it is slug feed with a chemical pot feeder.
How often should I check the chemicals in my chiller?

Depending how critical your system is, you may need to check it daily. On most very general water systems, once a week is good. Properly operating chiller systems are tight and should not loose much water. If you are losing chemical, you are losing water. So if you are always adding chemicals, you need to check for water loses.

What tests need to be perform on a chiller system?

Monitor the conductivity of the water and keep this for reference. Conductivity is and chemical usage is important when trouble shooting a system. Monitor the nitrite or based product used as a corrosion inhibitor and use dipslides to monitor bacteria development.

Wednesday 9 October 2019

SIZE OF SEWAGE TREATMENT PLANT / CAPACITY OF SEWAGE


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SIZE OF SEWAGE TREATMENT PLANT / CAPACITY  OF SEWAGE 


Before Calculating the size of STP calculate Total Domestic  Water Demand Required

Total domestic water demand  =  TWD 
Estimated Sewage X = 90 % of TWD
Estimate Sewerage X  = 90/100 * TWD

For  If TWD = 1600 KLD( Kilo  liter per day)

Capacity of S.T.P           = 90 / 100 * 1600 KLD
                                                      = 1440 KLD

 Space Requirement For 1440 Cum STP = 

Consider Total Depth 3.00 (Standard Depth )

Liquid Depth  L = 3.0 Mtr

 Size Of STP = 1440/3 = 480
                        =480/15 (Breadth Assumed) = 32 (Width )

Total Space =15*32*3= 1440 CUM 

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Tuesday 8 October 2019

Thumb rules for designing a Column layout


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Thumb rules for designing a Column layout


Three thumb rules to be followed are as follows:

  1. Size of the Columns
  2. Distance between Columns
  3. Alignment of columns

1.Minimum Size of RCC columns

The size of the columns depends on the total load on the columns. There are axial loads and lateral loads. Large beam spans induce bending moment not only in the beams, but also in columns which are pulled by the stresses in the beams. It is important to use advanced structural design software like ETabs or Staad pro. I highly recommend every structural designer learn these software. The thumb rules are for general designing in very small projects.
For this general thumb rule, we will assume a structure of G+1 floors high, using standard 6″ walls.
Minimum size of an RCC column should not be less than 9” x 12” (225mm x 300mm) with 4 bars of 12 MM Fe415 Steel.
These days the minimum I use in my projects is 9″ x 12″ (225 mm x 300mm) with 6 bars of 12 MM Fe500 steel. You can never go wrong with strong columns. I also recommend use of M20 grade concrete for the structure (ratio 1 part Cement : 1.5 parts Sand : 3 parts Aggregate with 0.5 parts water by volume). I recommend use of 8 MM stirrups at a distance of 150 MM center to center throughout the length of column.
This setup of 9″ x 12″ RCC columns is safe for G+1 Floors. There are a lot of other considerations, but this is just a thumb rule.

2.Span (distance) between two columns

For the above column setup, a span of up to 5 meters is quite safe. One can use beams of size 9″ X 12″ (225 MM x 300MM) with a slab thickness of 5″ (125 MM) cast in M20 concrete for spans up to 5m. There are other considerations like secondary and tertiary spans, point loads and wall loads which have to be considered. It is complicated, but thumb rules can work if the structure is simple. It is always recommended to use structural design software like ETabs or Staad pro for design.
In a beam of up to 5 meters length, secondary spans of up to 4 meters, wall loads of up to 8 kN per running meter, I can use steel as below.
  • Top Steel – 2 bars of 12 MM
  • Crank bars – 2 bars of 12 MM, cranked at an angle of 45° at a distance of L/4 at both ends of a simply supported beam
  • Bottom Steel – 3 bars of 12 MM.
This configuration can change depending on a lot of factors.

3.Alignment of Columns

Placing of columns depend completely on the plan. A planner has a very important job. A grid column placement is always preferred in order to reduce point loads and unnecessary complications while construction. This reduces the cost of construction as well as time required for construction. Beams which have continuity with other simply supported beams have reduced bending moments, and thus require less steel and concrete depth to be safe.

Columns have to be connected with each other for smooth transfer of loads. An experienced planner will keep such things in mind when planning the structure.

Monday 7 October 2019


Understanding Grades of Concrete
Grades of concrete are defined by the strength and composition of the concrete, and the minimum strength the concrete should have following 28 days of initial construction. The grade of concrete is understood in measurements of MPa, where M stands for mix and the MPa denotes the overall strength.
 
Concrete mixes are defined in ascending numbers of 5, starting at 10, and show the compressive strength of the concrete after 28 days. For instance, C10 has the strength of 10 newtons, C15 has the strength of 15 newtons, C20 has 20 newtons strength and so on.
 
Different mixes (M) come in various mix proportions of the various ingredients of cement, sand and coarse aggregates. For instance, M20 comes in the respective ratio of 1:1:5:3. You can see other examples below in the table.
 
Concrete GradeMix Ratio (cement : sand : aggregates)Compressive Strength
MPa (N/mm2)psi

Grades of Concrete
M51 : 5 : 105 MPa725 psi
M7.51 : 4 : 87.5 MPa1087 psi
M101 : 3 : 610 MPa1450 psi
M151 : 2 : 415 MPa2175 psi
M201 : 1.5 : 320 MPa2900 psi

Standard Grade of Concrete
M251 : 1 : 225 MPa3625 psi
M30Design Mix30 MPa4350 psi
M35Design Mix35 MPa5075 psi
M40Design Mix40 MPa5800 psi
M45Design Mix45 MPa6525 psi


High Strength Concrete Grades
M50Design Mix50 MPa7250 psi
M55Design Mix55 MPa7975 psi
M60Design Mix60 MPa8700 psi
M65Design Mix65 MPa9425 psi
M70Design Mix70 MPa10150 psi
 

Sunday 6 October 2019

How deep is a sump pit?

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How deep is a sump pit?
The typical pit is 30 inches in depth and 18 to 24 inches across. The standard sump pit insert available in home improvement centers is 26 gallons and 18 inches diameter. In many cases the pit needs to be a minimum of 24 inches and up to a depth of 36 inches. But some builders just use a common 5-gallon bucket.
A small pit fills up with water very quickly and the sump pump has to turn on and off frequently, which shortens the life of the pump and of its check valve. Installing a store-sold backup pump in a small basin is impractical because of the risk of its float getting stuck and basement flooding.
In case the sump pit is still too small or crowded, you may need to dig through the bottom of the pail to place the main pump deeper or to cut the concrete and install a full-size sump pit. But many pumps have set turn-on level of 6 to 8" and turn-off at 3" level. Then, making the pit deeper would not affect the short-cycling of the pump. A larger diameter pit will take longer to fill, or install a pump with a switch that turns the pump on at a much higher level.
When the sump pump short-cycles, its thermal overload protection kicks in and shuts the pump down – the basement floods even though the sump pump is not broken and will return back to normal after it cools down.
The Hi & Dry backup pumps will not trip! They are placed well above the pit or the normal water level. Inside the pit, they only need enough space for the suction pipe and a float. And Hi & Dry battery pumps feature a slim-line vertical switch to avoid the risk of entanglement.

Sunday 28 July 2019

All Estimated salary scale as per Education and Position in Saudi Arabia and UAE


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All Estimated salary scale as per Education and Position  in Saudi Arabia and UAE 

SAR - Saudi Riyal
AED - UAE Dihram  

Civil / Architect Engineer (Designer)                AED / SAR 9k - AED 20k Per Month
Min Qualification B.E/ B.Tech 5 to 10  experience 

Civil / Architect Engineer (Site Engineer)         AED / SAR 5k - AED 16k Per Month
Min Qualification B.E/ B.Tech 5 to 10  experience 

Civil / Architect Inspector                                 AED / SAR 5.5 k - AED 10k Per Month
Min Qualification Three Years Diploma / Ten year experience / B.E/ B.Tech two years experience

Civil / Architect Engineer (QA/QC Engineer )  AED / SAR 4k - AED 12k Per Month
Min Qualification Three Years Diploma / Ten year experience / B.E/ B.Tech two years experience


Civil / Architect Supervisor                               AED / SAR 3k - AED 9k Per Month
Min Qualification Three Years Diploma / Five year experience 


Civil / Architect Draft-Man AutoCAD Operator    AED / SAR 4k - AED 9k Per Month 
Min Qualification Three Years Diploma OR Short course in AutoCad  


Mechanical Engineer (Designer)                AED / SAR 9k - AED 20k Per Month
Min Qualification B.E/ B.Tech 5 to 10  experience 

Mechanical Engineer (Site Engineer)         AED / SAR 5k - AED 16k Per Month
Min Qualification B.E/ B.Tech 5 to 10  experience 

Mechanical Inspector                                 AED / SAR 5.5 k - AED 10k Per Month
Min Qualification Three Years Diploma / Ten year experience / B.E/ B.Tech two years experience

Mechanical Engineer (QA/QC Engineer )  AED / SAR 4k - AED 12k Per Month
Min Qualification Three Years Diploma / Ten year experience / B.E/ B.Tech two years experience


Mechanical Supervisor                               AED / SAR 3k - AED 9k Per Month 
Min Qualification Three Years Diploma / Five year experience 


Mechanical Draft-Man AutoCAD Operator    AED / SAR 3k - AED 9k Per Month  
Min Qualification Three Years Diploma OR Short course in AutoCad  

MEP Manager (Mecanical / Electrical Engineer)      AED / SAR 12k - AED 20k Per Month   
Min Qualification B.E/ B.Tech 10 to 15  experience 


Electrical  Engineer (Designer)                AED / SAR 9k - AED 20k Per Month
Min Qualification B.E/ B.Tech 5 to 10  experience 

Electrical  Engineer (Site Engineer)         AED / SAR 5k - AED 16k Per Month
Min Qualification B.E/ B.Tech 5 to 10  experience 

Electrical  Inspector                                 AED / SAR 5.5 k - AED 10k Per Month
Min Qualification Three Years Diploma / Ten year experience / B.E/ B.Tech two years experience

Electrical Mechanical Engineer (QA/QC Engineer )  AED / SAR 4k - AED 12k Per Month
Min Qualification Three Years Diploma / Ten year experience / B.E/ B.Tech two years experience

Electrical Supervisor                               AED / SAR 3k - AED 9k Per Month 
Min Qualification Three Years Diploma / Five year experience 


Electrical Draft-Man AutoCAD Operator    AED / SAR 3k - AED 9k Per Month
Min Qualification Three Years Diploma OR Short course in AutoCad  
    

MEP Manager (Mecanical / Electrical Engineer)      AED / SAR 12k - AED 20k Per Month 
Min Qualification B.E/ B.Tech 10 to 15  experience 

Civil Team Leader Manager (Civil / Architect Engineer)      AED / SAR 12k - AED 20k Per Month   

  Project Engineer (Team Leader)        AED / SAR 12k - AED 24k Per Month

Sr. Structural Engineer                            AED / SAR 10k - AED 20k Per Month

Project Manager, (Unspecified Type / General) 
                            AED / SAR 15k - AED 25k Per Month


Project Manager, Construction   AED / SAR 15k - AED 30k Per Month

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Mechanical Piping Engineer Most Important Interview Question and Answer

Mechanical PIPING Engineering  Interview Questions and Answer
This is help Full for Piping QA/QC Engineer , Piping Inspector ,Oil and Gas Piping Engineer and Sr Mechanical Piping Engineer

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Written By Afreen Ali

01.      What are the steps in selection of valve?
ANSWER :-  What to handle, liquid, gas or powder, fluid nature, function, construction material, disc type, stem type, how to operate, bonnet type, body ends, delivery time, cost, warranty.

02.      What are functions of valves? 
ANSWER :-  Isolation, regulation, non-return and special purposes.

03. What are isolating valves?
ANSWER :-  Gate, ball, plug, piston, diaphragm, butterfly, pinch.

04.      What are regulation valves? 
ANSWER :-  Globe, needle, butterfly, diaphragm, piston. pinch.

05.      What are non-return valves? 
ANSWER :-  check valve.

06.      What are special valves?
 ANSWER :-  multi-port, flush bottom, float, foot, pressure relief, breather.

07.      What materials are used for construction of valves?
ANSWER :-  Cast iron, bronze, gun metal, carbon steel, stainless steel, alloy carbon steel, polypropylene and other plastics, special alloys.

08.      What is trim?
ANSWER :-  Trim is composed of stem, seat surfaces, back seat bushing and other small internal parts that normally contact the surface fluid.

09.      Which standard specifies trim numbers for valve? 
ANSWER :-  API 600.

10.      What are wetted parts of valve?
 ANSWER :-  All parts that come in contact with surface fluid are called wetted parts.
11.      What is wire drawing?
ANSWER :-  This term is used to indicate the premature erosion of the valve seat caused by excessive velocity between seat and seat disc, when valve is not dosed tightly.

12.      What is straight through valve?
ANSWER :-  Valve in which the dosing operation of valve is achieved by 90 degrees turn of the dosing element.

13.      What pressure tests are carried out on valves? 
ANSWER :-  Shell-hydrostatic, seat-hydrostatic, seat-pneumatic

14.      What are available valve operators?
ANSWER :-  Handlever, handwheel, chain operator, gear operator, powered operator likes electric motor, solenoid, pneumatic and hydraulic operators, Quick acting operators for non-rotary valves (handle lift).

15. What are ball valve body types?
ANSWER :-  Single piece, double piece, three piece, the short pattern, long pattern, sandwich and flush bottom design.

16. What are two types of ball valve? 
ANSWER :-  Full port design and regular port design, according to type of seat, soft seat and metal seat.

17. Why ball valves are normally flanged?
 ANSWER :-  Because of soft seat PTFE which can damage during welding.

18. What are butterfly valve types? 
ANSWER :-  Double flange type, wafer lug type and wafer type.

19. What are types of check valve? 
ANSWER :-  Lift check valves and swing check valves.

20. What are non-slam check valves?
ANSWER :-  Swing check valve, conventional check valve, wafer check valve, tilting disc check valve, piston check valve, stop check valve, ball check valve.

21. Where stop check valve is used?
ANSWER :-  In stem generation by multiple boilers, where a valve is inserted between each boiler and the main steam header. It can be optionally dosed automatically or normally.

22. Where diaphragm valves are used? 
ANSWER :-  Used for low pressure corrosive services as shut off valves.

23. Where diaphragm valves are used?
ANSWER :-  Used for low pressure corrosive services as shut off valves.

24. What is Barstock Valve?
ANSWER :-  Any valve having a body machined from solid metal (barstock). Usually needle or globe type.

25. What is BIBB Valve? 
ANSWER :-  A small valve with turned down end, like a faucet.

26. What is Bleed Valve? 
ANSWER :-  Small valve provided for drawing off liquid.

27. What is BlowDown Valve?
ANSWER :-  Refers to a plug type disc globe valve used for removing sludge and sedimentary matter from the bottom of boiler drums, vessels, driplegs etc.

28. What is Breather Valve?
ANSWER :-  A special self acting valve installed on storage tanks etc. to release vapour or gas on slight increase of internal pressure (in the region of 1/2 to 3 ounces per square inch).

29. What is Drip Valve? 
ANSWER :-  A drain valve fitted to the bottom of a droplet to permit blowdown.

30.What is Flap Valve?
 ANSWER :-  A non return valve having a hinged disc or rubber or leather flap used for low pressure lines.

31.What is Hose Valve?
ANSWER :-  A gate or globe valve having one of its ends externally threaded to one of the hose thread standards in use in the USA. These valves are used for vehicular and firewater connections.

32.What is Paper-Stock Valve?
ANSWER :-  A single disc single seat gate valve (Slide gate) with knife edged or notched disc used to regulate flow of paper slurry or other fibrous slurry.

33.What is Root Valve?
ANSWER :-  A valve used to isolate a pressure element or instrument from a line or vessel, or a valve placed at the beginning of a branch form the header.

34. What is Slurry valve? 
ANSWER :-  A knife edge valve used to control flow of non-abrasive slurries.

35. What is Spiral sock valve? 
ANSWER :-  A valve used to control flow of powders by means of a twistable fabric tube or sock.

36. What is Throttling valve? 
ANSWER :-  Any valve used to closely regulate flow in the just-open position.

37.   What is relief valve?
ANSWER :-  Valve to relieve excess pressure in liquids in situations where full flow discharge is not required, when release of small volume of liquid would rapidly lower pressure.

38.   What is safety valve?
 ANSWER :-  Rapid opening (popping action) full flow valve for air and other gases.

39.   What is foot valve?
ANSWER :-  Valve used to maintain a head of water on the suction side of sump pump. basically a lift check valve with integrated strainer.

40. What is float valve?
ANSWER :-  Used to control liquid level in tanks, operated by float, which rises with liquid level and opens the valve to control water level. It can also remove air from system, in which case, air flows out of system in valve open condition, but when water reaches valve, float inside valve raises to dose the valve and stop flow of water. Used in drip legs.

41.      What are flush bottom valves?
ANSWER :-  Special type of valves used to drain out the piping, reactors and vessels, attached on pad type nozzles.

42.      What are types of flush bottom valves? 
ANSWER :-  Valves with discs opening into the tank and valves with disks into the valve.

43.   What are types of flush bottom valves? 
ANSWER :-  Valves with discs opening into the tank and valves with disks into the valve.

44.   What are the uses of three-way valve?
ANSWER :-  Alternate connection of the two supply lines to a common delivery vise versa, isolating one safety valve, division of flow with isolation facility.

45.   What are uses of four way valve?
ANSWER :-  Reversal of pump suction and delivery, By pass of strainer or meter, reversal of flow through filter, heat exchanger or dryer.

46.   What is metal seated lubricated plug valve?
ANSWER :-  A plug valve with no plastic material, where grease is applied to contacting surfaces for easy operation.

47.   What are three patterns of plug valve design? 
ANSWER :-  Regular pattern, short pattern and ventury pattern.

48. What is regular pattern plug valve?
ANSWER :-  Rectangular port, area almost equal to pipe bore, smooth transition from round body to rectangular port, for minimum pressure loss.

49. What are short pattern plug valve?

ANSWER :-  Valves with face to face dimension of gate valve, as a alternative to gate valve.

50.     What are ventury pattern plug valve?
ANSWER :-  Change of section through the body throat so graded to have ventury effect, minimum pressure loss.
50A.     What are inverted plug design valve? 
ANSWER :-  Plug valve with taper portion up of plug. For 8" and higher size.
51.     What is pressure balanced plug valve?
ANSWER :-  With holes in port top and bottom connecting two chambers on top and bottom of plug, to reduce turning effort.
52.     What are Teflon sleeved plug valve?
ANSWER :-  PTFE sleeve between plug and body of valve, low turning effort, minimum friction, temperature limitation, anti static design possible.
53.     What are permasil plug valve?
ANSWER :-  Plug valves with Teflon seat instead of sleeves, for on-off applications, can handle clean viscous and corrosive liquids, Graphite seat for high temperature applications. Drip tight shut off not possible.
54.     What are eccentric plug valve?
ANSWER :-  Off center plug, corrosive and abrasive service, on off action, moves into and away from seat eliminating abrasive wear.

55.   What is pinch valve?
ANSWER :-  Similar to diaphragm valve, with sleeves of rubber or PTFE, which get squeezed to control or stop the flow, Cast iron body, for very low service pressures like isolation of hose connections, manufacture standard.
56.   What is needle valve?
ANSWER :-  Full pyramid disc, same design as globe valve, smaller sizes, sw or threaded, flow control, disc can be integral with stem, inside screw, borged or barstock body and bonnet, manufacturers standard.
57.   How to install a globe valve?
ANSWER :-  Globe valve should be installed such that the flow is from the underside of the disk, Usually flow direction is marked on the globe valve.
58.   What are globe valve port types? 
ANSWER :-  Full port: More than 85% of bore size, Reducer port: One size less than the connected pipe.
59.   What are globe valve disk types?
ANSWER :-  Flat faced type for positive shutoff, loose plug type for plug renewal or needle type for finer control.
60.   What are characteristics of globe valve stem? 
ANSWER :-  Always rising design, with disk nut at the lower end and handwheel at upper end.

61.   What is pinch valve?
ANSWER :-  Similar to diaphragm valve, with sleeves of rubber or PTFE, which get squeezed to control or stop the flow, Cast iron body, for very low service pressures like isolation of hose connections, manufacture standard.
62.   What is needle valve?
ANSWER :-  Full pyramid disc, same design as globe valve, smaller sizes, sw or threaded, flow control, disc can be integral with stem, inside screw, borged or barstock body and bonnet, manufacturers standard.
63.   How to install a globe valve?
ANSWER :-  Globe valve should be installed such that the flow is from the underside of the disk, Usually flow direction is marked on the globe valve.
64.   What are globe valve port types?
 ANSWER :-  Full port: More than 85% of bore size, Reducer port: One size less than the connected pipe.
65.   What are globe valve disk types?
ANSWER :-  Flat faced type for positive shutoff, loose plug type for plug renewal or needle type for finer control.
66.   What are characteristics of globe valve stem? 
ANSWER :-  Always rising design, with disk nut at the lower end and handwheel at upper end.

67.   What are types of globe valve?
ANSWER :-  Angle globe valve, plug type disc globe valve, WYE-body globe valve, composite disc globe valve, double disc globe valve.
68.   What is angle globe valve? 
ANSWER :-  Ends at 90 degree to save elbow, higher pressure drop.
69.   Where plug type disc globe valve is used?
ANSWER :-  For severe regulating service with gritty liquids such as boiler feedwater and for blow off service.
70.   Where WYE body globe valve is used? 
ANSWER :-  In line ports with stem emerging at 45 degree, for erosive fluids due to smoother flow pattern.
71.   What is double disc globe valve?
ANSWER :-  Has two discs bearing on separate seats spaced apart, on a single shaft, for low torque, used for control valves.
72.   What are port types for gate valves? 
ANSWER :-  Full port and reduced port. Default is reduced bore. Full port has to be specified in bom.
73.   How to close a gate valve? 
ANSWER :-  Turn the hand wheel in clockwise direction.

74.   What are port types for gate valves?
 ANSWER :-  Full port and reduced port. Default is reduced bore. Full port has to be specified in bona.
75.   How to close a gate valve? 
ANSWER :-  Turn the hand-wheel in clockwise direction.
76.   What is lantern ring?
ANSWER :-  It's a collection point to drain off any hazardous seepage or as a point where lubricant can be injected; it is in the middle of packing rings.
77.   What are types of gate valves?
ANSWER :-  Solid plane wedge, solid flexible wedge, split wedge, double disc parallels seats, double disc wedge, single disc single seat gate or slide, single disc parallel seats, plug gate valve.
78.   What are the types of bonnets?
ANSWER :-  Bolted bonnet, bellow sealed bonnet, screwed on bonnet, union bonnets, A U-bolt and damp type bonnet, breech-lock bonnet, pressure seal bonnet.


79 . What is preferred location for drain?
ANSWER :-  Must be located at the bottom section of drum.

80. What are the steps in selection of valve?
ANSWER :-  What to handle, liquid, gas or powder, fluid nature, function, construction material, disc type, stem type, how to operate, bonnet type, body ends, delivery time, cost, warranty.

81. What are functions of valves?
 ANSWER :-  Isolation, regulation, non-return and special purposes.

82. What are isolating valves? 
ANSWER :-  Gate, ball, plug, piston, diaphragm, butterfly, pinch.

83. What are regulation valves?
ANSWER :-  Globe, needle, butterfly, diaphragm, piston, pinch.

84. What are non-return valves? 
ANSWER :-  check valve,

85. What are special valves? 
ANSWER :-  multi-port, flush bottom, float, foot, pressure relief, breather.

86. What materials are used for construction of valves?
ANSWER :-  Cast iron, bronze, gun metal, carbon steel, stainless steel, alloy carbon steel, polypropylene and other plastics, special alloys.

87.  What is trim?
ANSWER :-  Trim is composed of stem, seat surfaces, back seat bushing and other small internal parts that normally contact the surface fluid.

 88.Which standard specifies trim numbers for valve? 
ANSWER :-  API 600.

 89.  What are wetted parts of valve?
ANSWER :-  All parts that come in contact with surface fluid are called wetted parts.

90. What is wire drawing?
ANSWER :-  This term is used to indicate the premature erosion of the valve seat caused by excessive velocity between seat and seat disc, when valve is not dosed tightly.

91. What is straight through valve?
ANSWER :-  Valve in which the closing operation of valve is achieved by 90 degrees turn of the closing element.

92.What pressure tests are carried out on valves?
 ANSWER :-  Shell-hydrostatic, seat-hydrostatic, seat-pneumatic

93.What are available valve operators? 
ANSWER :-  Hand-lever, hand-wheel, chain operator, gear operator etc.

94. What is the full form of ASME?
ANSWER :-  American Society for Mechanical Engineers.


95. Which Piping code is used for Power piping and which code is used for Process Piping design?
ANSWER :-
o  Power Piping: ASME B 31.1
o  Process Piping: ASME B 31.3

96.  What are the main differences between ASME B 31.1 and ASME B 31.3? 
ANSWER :-  The main differences are listed below:
o  Material allowable stresses are different in both codes.
o  Stress increases due to occasional loads are different in each code.
o  B 31.3 neglects torsion while calculating sustained stresses, but B 31.1 includes it.
o  Sustained stress calculation is specific in B 31.1 but undefined for B 31.3.
o  B 31.1 intensifies torsion but B31.3 does not intensify it.

97.   How to calculate the basic allowable stress for a material?
ANSWER :-  The basic allowable stress is defined in respective code. For example as per B 31.3 the basic allowable stress for a material is the minimum of the following:
1/3rd of tensile strength at design temperature.
2/3rd of yield strength at design temperature.
i00% of average stress for a creep rate of o.oi% per woo hours.
67% of average stress for rupture at the end of w0000 hours.
8o% of minimum stress for ruptures at the end of w0000 hours.
For austenitic stainless steel or nickel alloys the lower of yield strength and go% of yield strength at temperature.
For structural grade materials 0.92 times of the lowest value of point (a) to (f)

98.   What is the main difference between Constant and Variable Spring Hanger? When to use these hangers?
ANSWER :-
o  In Constant Spring hanger the load remains constant throughout its travel range. But In variable spring hanger the load varies with displacement.
o  Spring hangers are used when thermal displacements are upwards and piping system is lifted off from the support position. Variable spring hanger is preferable as this is less costly.
o  Constant springs are used:
o  When thermal displacement exceeds 5o mm
o  When variability exceeds 25%
o  Sometimes when piping is connected to strain sensitive equipment like steam turbines, centrifugal compressors etc and it becomes very difficult to qualify nozzle loads by variable spring

99. What are the types of compressors?
ANSWER :-  Positive Displacement, Centrifugal and Axial, rotary screw, rotary vane, rotary lobe, dynamic, liquid ring compressors.

100. What are types of compressor drives? 
ANSWER :-  Electric motor, gas turbine, steam turbine and gas engine.

101. How Centrifugal compressors work?
ANSWER :-  High-speed impellers increase the kinetic energy of the gas, converting this energy into higher pressures in a divergent outlet passage called a diffuser. Large volume of gas at moderate pressure.

102.What are types of steam turbine and why are they popular?
ANSWER :-  Condensing and non-condensing, Popular because can convert large amounts of heat energy into mechanical work very efficiently.

103. Where gas turbine drive is used?
ANSWER :-  Desserts and offshore platforms where gas is available, for gas transmission, gas lift, liquid pumping, gas re-injection and process compressors.

104. What are the auxiliary equipments of compressor?
ANSWER :-  Lube oil consoles, Seal oil consoles, Surface condensers, Condensate pump, Air blowers, Inlet air filters, waste heat system, compressor suction drum, knock out pot, Pulsation dampner, volume bottles, Inter and after coolers.

105. What are the types of seal oil system? 
ANSWER :-  Gravity and pressurized.

106. What factors to be considered while designing compressor housing? 
ANSWER :-  Operation, Maintenance, Climate conditions, Safety, Economics.

107. What are the compressor housing design points?
 ANSWER :-  Floor elevation, building width, building elevation, hook centerline elevation.

108. What are the types of compressor cases? 
ANSWER :-  Horizontal split case, Vertical split case.

109. How to located temperature and pressure instruments?
ANSWER :-  Temperature in liquid space, at down-corner side and pressure in vapour space, in area except down-corner sector

110.   What are necessary parts of inlet line of compressor?
ANSWER :-  Block Valve, Strainer, Break out flanges in both inlet and outlet to remove casing covers, Straightening vane in inlet line if not enough straight piece in inlet line available, PSV in interstage line and in discharge line before block valve.

110A. What points to be considered for reciprocating compressor piping layout? 
ANSWER :-  High pulsation, simple line as low to grade as possible for supporting, analog study, all branches dose to line support and on top, Isolate line support from adjacent compressor or building foundations