SPECIFIC SPEED

Specific speed

Specific speed (NS) is calculated from:

NS = [N x FAQ^0.50] / [H^0.75]

N = pump speed, RPM
FAQ = capacity at best efficiency point (BEP) at maximum impeller diameter,
GPMH = head at BEP at maximum impeller diameter, FT

Specific speed identifies the type of pump according to its design and flow pattern. According to this criteria a pump can be classified as radial flow, mixed flow, or axial flow type. A radial flow pump is one where the impeller discharges the liquid in the radial direction from the pump shaft centerline, an axial flow pump discharges the liquid in the axial direction and a mixed flow pump is one that is a cross between a radial and an axial flow pump design.Specific speed identifies the approximate acceptable ratio of the impeller eye diameter (D1) to the impeller maximum diameter (D2) in designing a good impeller.

NS: 500 to 5000; D1/D2 > 1.5 - radial flow pump
NS: 5000 to 10000; D1/D2 <1.5>NS:10000 to 15000; D1/D2 = 1 - axial flow pump

NPSH

NPSH

A minimum amount of suction pressure (head) is needed for a pump to operate without cavitating. The term used to describe this suction pressure is Net Positive Suction Head (NPSH). The amount of NPSH the pump requires to avoid cavitation is called NPSHr. The amount of NPSH available to the pump from the suction line is termed NPSHa. When selecting a pump it is necessary to see how much NPSH it requires at the duty point and make sure the NPSH available exceeds that amount. It is normal practice to have at least 2 feet of extra NPSH available at the suction flange to avoid any problems at the duty point. Also, if the pump were inadvertently operated at a flow higher than the rating point then a higher NPSH would be required to avoid cavitation\

NET POSITIVE SUCTION HEAD:

Flooded suction:
NPSH = ha - hv + hs - hf

Suction lift:
NPSH = ha – hv - hs - hf

ha = the absolute pressure in feet of liquid on the surface of the supply liquid.
hv = the vapor pressure of the liquid being pumped expressed in feet of head.
Hs = the height in feet of the supply liquid surface with respect to the pump inlet.
Hf = suction line friction losses expressed in feet of head.

These calculations yield the available net positive suction head for a given system. This must be compared to the required net positive suction head NPSHr calculated by the manufacturer. NPSHa must exceed NPSHr.

PUMP CAVITATION

CAVITATION

Cavitation means that cavities or bubbles are forming in the liquid that we're pumping. These cavities form at the low pressure or suction side of the pump, causing several things to happen all at once:

* The cavities or bubbles will collapse when they pass into the higher regions of pressure, causing noise, vibration, and damage to many of the components.

*We experience a loss in capacity.

* The pump can no longer build the same head (pressure)

* The pump's efficiency drops.

The cavities form for five basic reasons and it's common practice to lump all of them into the general classification of cavitation. This is an error because we'll learn that to correct each of these conditions, we must understand why they occur and how to fix them. Here they are in no particular order :

1. Vaporization
2. Air ingestion (Not really cavitation, but has similar symptoms)
3. Internal recirculation
4. Flow turbulence
5. The Vane Passing Syndrome

MECHANICAL SEALS

Mechanical Shaft Seals

1. Operating Principles & Fundamentals
Since the development of the basic mechanical seal introduction of new and innovative seal technologies has enabled mechanical seal installation on virtually any fluid handling application. To sort through which seal design will provide optimum performance a thorough understanding of mechanical seal principles and fundamentals is mandatory.

A. Pusher & Non-Pusher Seal Designs: Pusher seals, while generally less expensive than non-pusher seal designs, will have a tendency to "hang-up" on the pump shaft when handling fluids which coke or crystallize as the secondary sealing member which must accommodate for travel as the seal faces wear is unable.

B. Seal Driving & Spring Compression: The rotary portion of a mechanical seal is either positive or friction drive. Incorporating an improper driving arrangement on a given application will result in premature and catastrophic failure.

C. Balanced & Unbalanced Seals: This difference in seal design will make the difference in seal performance. An unbalanced mechanical seal seeing high pressures has the fluid film between the seal faces reduced due to high hydraulic face loading resulting in overheating, rapid face wear, and premature seal failure.

D. Inside & Outside Seal Mounting: While inside mechanical seals are a preferred method outside seals can be used when fitting a pump with a shallow stuffing box which cannot dimensionally accommodate an inside seal.

Mechanical seals as per construction:

} single coil spring seal

} multi coil spring seal

} metal bellows seal

} rubber/ Teflon below seal

Seal categories:

}Category 1 :
seals are intended for use in non-ISO 13709 pump seal chambers, their application is limited to seal chamber temperatures from – 40 °C to 260 °C and absolute pressures up to 22 bar (315 psi).

}Category 2 :
Dimensional requirements of ISO 13709. Their application is limited to seal chamber temperatures from – 40 °C to 400 °C and absolute pressures up to 42 bar (615 psi).

}Category 3 :

provides the most rigorously tested and documented seal design. It is required that the entire seal cartridge is qualification tested as an assembly in the required fluid. They meet the seal chamber envelope requirements of ISO 13709 (or equal). Their application is limited to seal chamber temperatures from – 40 °C to 400 °C and absolute pressures up to (42 bar) (615 psi).

Seal types

>Type A :
seal is a balanced, inside-mounted, cartridge design, pusher seal with multiple springs and in which the flexible element normally rotates. Secondary sealing elements are elastomeric O-rings.

>Type B :
seal is a balanced, inside-mounted, cartridge design, non-pusher (metal bellows) seal in which the flexible element normally rotates. Secondary sealing elements are elastomeric O-rings.

>Type C :
seal is a balanced, inside-mounted, cartridge-design non-pusher (metal bellows) seal in which the flexible element is normally stationary. Secondary sealing elements are flexible graphite.

Seal arrangements

*Arrangement 1:
Seal configurations having one seal per cartridge assembly;

*Arrangement 2:
Seal configuration having two seals per cartridge assembly, with the space between the seals at a pressure less than the seal chamber pressure.

*Arrangement 3:
Seal configurations having two seals per cartridge assembly, utilizing an externally supplied barrier fluid at a pressure greater than the seal chamber pressure.

Seal orientations

-Arrangement 2 and Arrangement 3 seals can be in the following three orientations:

1. face-to-back (TANDEM OR FACING IN THE SAME DIRECTION) :

dual seal configuration in which one mating ring is mounted between the two flexible
elements and one flexible element is mounted between the two mating rings;

2. back-to-back (FACING IN OPPOSITE DIRECTION) :

dual seal configuration in which both of the flexible elements are mounted between the
mating rings; and

3.face-to-face (FACING TOWARDS EACH OTHER) :

dual seal configuration in which both of the mating rings are mounted between the flexible elements.

FLUSHING

-Why flushing is required ?

* To remove heat from seal faces generated due to friction between faces.
* To provide clean water for seal face lubrication
* To contains the leakage with-in a confined space and act as leakage carrier to safe location

- DIFFERENT METHODS OF BRINGING FLUID TO STUFFING BOX


1. DISCHARGE RECIRCULATION

2. SUCTION RECIRCULATION

3. FLUSHING

4. BARRIER/BUFFER FLUID

DUAL SEAL ARRANGEMENT

- TO PREVENT A COSTLY PRODUCT FROM LEAKING

- TO PREVENT DANGEROUS PRODUCT FROM LEAKING

- TO PREVENT A POLLUTENT FROM ESCAPING TO THE ATM.

- AS A BACKUP SEAL

FLUSHING PLANS

1. Plan 01 :
internal porting is used to direct flow to the seal chamber from an area behind the impeller near the discharge.

2. Plan 02 :
dead-ended seal chamber with no flush fluid circulation

3. Plan 11 :
product is routed from the pump discharge to the seal chamber .

4. Plan 13 :

Suction recirculation

5. Plan 14 :
combination of a Plan 11, recirculation from pump discharge, and Plan 13, recirculation to pump suction.

6. Plan 21 :

Recirculation from discharge thru orifice & cooler

7. Plan 22 :
Plan 21 with strainer

8. Plan 23 :

equipped with an internal circulating device that circulates seal chamber fluid through a cooler and back to the seal chamber

9. Plan 31 :
product is routed from the discharge of the pump into a cyclone separator.

10. Plan 32 :
the flushing product is brought from an external source to the seal.

11. Plan 52 :
Unpressurized buffer fluid circulation thru reservoir.fluid is circulated by pumpingring used with Arrangement 2 seals.

12. Plan 53A, Plan 53B, Plan 53C :
Pressurized barrier fluid circulation thru reservoir/blader/piston accumulator.Arrangement 3 pressurized dual seal systems

13. Plan 54 :
pressurized dual-seal systems with inner seal leakage into the pumped product

14. Plan 62 :

a quench stream is brought from an external source to the atmospheric side of the seal faces

15. Plan 71 :

Arrangement 2, unpressurized dual seals, which utilize a dry containment seal and where no buffer gas is supplied but the provision to supply a buffer gas is desired.

16. Plan 72 :
Arrangement 2 unpressurized dual seals. unpressurized buffer gas control.

17. Plan 74 :
Arrangement 3, dual pressurized seals, where the barrier medium is a gas. Pressurized barrier gas control system. The most common barrier gas is plant nitrogen

18. Plan 75 :
Arrangement 2, unpressurized dual seals, which also utilize a dry containment seal and where the leakage from the inner seal may condense.

19. Plan 76 :
Arrangement 2, unpressurized dual seals, which also utilize a dry containment seal and where leakage from the inner seal will not condense. Vent from containment seal cavity to vapor recovery.

INTRODUCTION TO PIPING COMPONENTS

INTRODUCTION TO PIPING COMPONENTS

1. PIPES

Piping in a particular plant can be compared with arteries & veins in our body. There are mainly two types of pipes from manufacturing point of view. The first is Seamless pipes & second is Welded pipes.

Various attributes of pipe are described below.

A) End Preparation:

There are three types of end preparation of pipes.
(a) Plain End (PE)
(b) Butt weld or Beveled End (BW/BE)
(c) Threaded End

B) Design & Dimension Standard:

This will provide the following information.

Nominal Bore (NB), Thickness, Outside Diameter (OD), Tolerance & Weight.

The Dimension Standard for pipe is as follows.

ANSI/ASME B 36.10 : For Carbon Steel (CS), Low Temperature Carbon Steel (LTCS), Low Alloy Steel (LAS) Pipes

ANSI/ASME B 36.19 : For Stainless Steel (SS) Pipes

C) Material

I. CS: It is used for temperature range from (–) 29°C to 4270C.
Most commonly used CS materials are as follows:

ASTM A 106 Gr. B (Seamless pipes)

API 5L Gr. B (Seamless & Welded)

ASTM A 53 Gr. B (Seamless & Welded)

IS 1239 (Upto 6” & ERW)

IS 3589 (Above 6”)

II. LTCS : It is used for low temperature i.e. from (–) 460C to 3430C.
The most commonly used LTCS materials are as follows:

ASTM A 333 Gr. 6 (Seamless pipes)

ASME A 671 (Welded pipes)

III. LAS : It is used for high temperature i.e. (-) 290C to 538°C
The most commonly used LAS materials are as follows:

ASTM A 335 Gr. P11, P12, P9 (Seamless pipes)

ASTM A 691 Gr.C60, C65, C70 (Welded pipes)



IV. SS : It is used for cryogenic temperature range i.e. from (-) 1960C to 5380C.
Most commonly used SS materials are as follows:

ASTM A 312 TP 304 / ASTM A 312 TP 304L

ASTM A 312 TP 316 / ASTM A 312 TP 316L

ASTM A 312 TP 321

(Various shortforms:
IS Indian Standard
ERW Electric Resistance Welding
LS * Standard)


2. FLANGES

Flanges are used to make a joint that is required to be dismantled.
Various attributes of Flanges are described below:

A) Type : There are five types of Flanges.

I. Weld Neck Flange

It has Butt Weld End Connection.
Radiography Test (RT) is possible.

II. Socket Weld Flange

Here Fillet welding is done from outside only.
Die Penetration Test (DP) is possible.

III. Slip On Flange

Here Fillet welding is done from inside as well as from outside.
DP Test is possible.

IV. Threaded Flange

It is mainly used in Galvanized pipes.

V. Blind Flange

It is used for ending a line.

B) Facing : There are four types of facing.

I. Raised Face

It is specified up to 600 (psi) rating pipe class.

II. Ring Joint

It is specified from 900 rating (psi) & above pipe class.

III. Flat Face

It is only used for 150 (psi) rating pipe class.
It is specified for utility fluids like Cooling Water and Low Pressure Nitrogen.

IV. Tongue & Groove

Its use is mainly dependent upon the nature of fluid to be handled.
It is specified to handle extremely hazardous fluids like Liquid Ammonia.

C) Design and Dimension Standard : The dimensional standards generally used are
ANSI/ASME B16.5 for size upto 24’ ANSI/ASME B16.47 series A & B for size above 24’’. Series B specifies compact design & is used when space and cost are the main constraints.

D) Material : Flanges are manufactured from following forged materials.

I. Carbon Steel – ASTM A 105 (used most of the times)
ASTM A 181 (it is obsolete now)

II. Low Temperature Carbon Steel — ASTM A 350 Gr. LF 2

III. Low Alloy Steel – ASTM A 182 Gr. F 11 (generally used)
ASTM A 182 Gr. F 1/F22/F9

IV. Stainless Steel – ASTM A 182 Gr. F 304
ASTM A 182 Gr. F 304 L
ASTM A 182 Gr. F 316
ASTM A 182 Gr. F 316 L
ASTM A 182 Gr. F 321

ASTM Sec. II A defines ferrous material. It gives detail properties of Ferrous Material
- Chemical Analysis
- Physical Properties (tensile strength,
Yield strength, hardness, etc.)

E) Pressure Class (Rating)

Rating is maximum allowable non-shock working gauge pressure. There are 150, 300, 600, 900, 1500, 2500 ratings. To select a pressure class the following two steps are followed.
Decide the group of material from Table 1A of ASME 16.5
Refer Table 2 of ASME 16.5 for design condition.

Spectacle Blind

It is not exactly a flange but it is kept between two flanges and is used for the temporary isolation of a line.

Design & Dimension Standard----LS 423-06
Material----Same as Flange
Facing----Same as Flange

Generally it is used up to 10” & above 10” it is used in two separate pieces. One is known as Slip Plate (Blind Part) & second is known as Slip Ring (Hollow Part).

3. PIPE FITTINGS

Pipe fittings are of different types.

3.1 Elbows : Used for change in direction of pipe routing.

(a) They are of 2 types :

45° Elbow which can be
Short Radius Elbow, R = 1D
Long Radius Elbow, R = 1.5D

90° Elbow which can be
Short Radius Elbow, R = 1D
Long Radius Elbow, R = 1.5D

(b) According to End connection elbows can be classified as

Socket Weld : for size upto 1½’’
Butt Weld : for size greater than 1½’’ ( > 2’’ in *)
Threaded : for size upto 1½’’ in G.I. Pipes

(c) Dimensional Standard

For Socket Weld & Threaded Elbows: ANSI/ASME B16.11
For Bevelled end Elbows: ANSI/ASME B 16.9

Thickness for Beveled end fittings = Thickness of pipe
Thickness for 3000# Socket weld elbows = Schedule 80 of respective pipe size.
Thickness for 6000# Socket weld elbows = Schedule 160 of respective pipe size.
Thickness for 9000# Socket weld elbows = Schedule XXS of respective pipe size.

(d) Pressure class for Socket Weld & Threaded Pipe Fitting It is as follows:

2000 psi or 2000 rating - used only for threaded pipe fittings

3000 psi - used only for Socket Weld Pipe fitting & threaded pipe fittings

6000psi - used only for Socket Weld Pipe fitting & threaded pipe fittings

9000psi - used only for Socket Weld Pipe fitting & threaded pipe fittings

(e) Material

Socket Weld and Threaded pipefitting are manufactured from following forged materials

(1) Carbon Steel – ASTM A 105

(2) Low Temperature Carbon Steel- ASTM A 350 Gr. LF2

(3) Low Alloy Steel – ASTM A 182 Gr. F11(generally used), F1, F6, F9

(4) Stainless Steel – ASTM A 182 Gr. F 304, F304L, F316, F316L, F321

Butt Weld pipe fittings are manufactured from pipes

(1) Carbon Steel – ASTM A 234 Gr. WPB

(2) Low Temperature Carbon Steel – ASTM A 420 Gr. WPL6

(3) Low Alloy Steel – ASTM A 234 Gr. WP11/WP22/WP9

(4) Stainless Steel – ASTM A 403 WP/304, 304L, 316, 316L, 321


3.2 Tee : Used for taking a branch.

(a) Tee can be

Equal/Straight tee – All 3 sizes are equal

Unequal/Reduced tee – Branch size is always smaller

Points (b), (c), (d) and (e) are same as elbows

3.3 Half Coupling : Used to take a branch upto 1½’’ size.

End connections are Socket Weld & Threaded
Used in Pipe class upto 300 rating

Points (c), (d), (e) same as elbow

3.4 Reducer/Expander : Used when change in pipe size is there.

Type – Concentric Reducer – Butt Weld

Eccentric Reducer – Butt Weld

In case of Eccentric Reducer one side is tapered while the other side is straight. Here the difference in elevation of the axis exists leading to eccentricity. Its construction is like a trapezoid.

In case of Concentric Reducer both sides are tapered and the axis is also the same. Its construction is like a cone.



Thumb Rule for Reduction:

Next Lower Size/2 ---> Higher Size

For E.g. if the Header Side is 6’’ then 6/2 = 3 and hence the next lower size possible is 2½’’.
Hence it can be seen that reduction from 6’’ to 2½’’ is possible. Further reduction beyond 2 ½’’ is not possible. Reducers can be manufactured in small size.

Dimension Standard: ANSI/ASME B16.9

Thickness is same as the pipe thickness.

Material: Same as BW Elbows

3.5 Full Coupling

: Used for Pipe to Pipe joint of small bore (upto1½’’)

End connections are Socket Weld & Threaded
Dimensional Standard, Material and Pressure class same as Half coupling

3.6 Weldolet:

Used to take Butt Weld branch for which Reducing tee is not possible
Used in high pressure, high temperature pipe class from 900 rating

Dimension Standard:

MSS SP 97
Header and Branch size with thickness is to be specified

Material:

Forged same as elbow / half coupling

3.7 Sockolets:

Same as Weldolet except there is a Socket weld end at Branch side.

Caps: Used at the end of the line for the termination of the line.

End Connection: The end connections are

Socket weld }

Up to 1 ½”
Threaded end }

Butt weld } Above 2”

Dimension Standard:

ANSI/ASME B 16.11 For SW & Threaded End
ANSI/ASME B 16.9 For BW/BE
Thickness for BW caps same as thickness of pipe.

Material: Same as Elbow

4. VALVES

Valves are used for main three purposes listed below.

For Isolation of flow.
For Regulation of flow.
For avoiding the reversal of the flow.

The valves used for isolation cannot be used for regulation but other way round is possible.

Various types of valves.
(1) Gate valve
(2) Ball valve
(3) Plug valve
(4) Butterfly valve
(5) Globe valve
(6) Needle valve
(7) Check valve
(8) Control valve (Handled by Instrumentation Department)
(9) Pressure relief valve or Safety valve (Handled by Instrumentation Department)

First five valves are used for isolating the flow, 5th & 6th valves are used for regulating the flow and 7th valve is used for avoiding the reversal of the flow.

4.1 GATE VALVE

It is the most commonly & very widely used valve in industrial piping for isolation of the flow. It is manually operated and it is not recommended for regulation of the flow. Installation of this valve is possible from both the ends. Hence it is bi-directional valve.

A) End Preparation:

(a) Cast Steel valves have Flanged or Butt weld end preparation.
(b) Forged Steel valves have Socket weld or Threaded end preparation.

B) Design & Dimension Standard:

The dimension Standard for gate valve is as follows.
API 600 :For Cast Steel valves (Flanged/BW valves)
API 602 :Forged Steel valves (SW/Threaded valves)
ANSI B 16.34 :For Pressure & Temperature limitation & Rating
ANSI B 16.10 :For face to face dimension of Flanged & BW end
API 598 :For Testing of valve

C) Main parts: Gate valve has following main parts.

Body
Bonnet
Internals/Trim/Wetted parts: Parts that come in direct contact with the fluid. Gate valve has following Internals/Trim/Wetted parts.
Wedge / Seat Ring / Stem / Gland Bush

D) Pressure Class:

There are 150,300,600,900,1500,2500 ratings for Flanged & BW valve.
There is 800 rating for SW or Threaded valve.

4.2 GLOBE VALVE

The fluid while passing through this valve changes its flow direction and hence this valve causes increased resistance to flow which result into considerable pressure drop. So this valve is not suitable where pressure drop is critical. This valve is mainly used for regulation of the flow.

Inlet and outlet of this valve are fixed. Hence installation of this valve is unidirectional. Flow direction is marked on the valve body.

A) End Preparation: Same as Gate valve.

B) Design & Dimension Standard:

BS 5352 :For SW/Threaded valves
BS 1873 :For Flanged/BW valves
ANSI/ASTM B 16.34 :For Pressure & Temperature limitation and Rating
ANSI/ASTM B 16.10 :For face to face dimension of Flanged/BW end valves
API 598 :For Testing of valve

C) Main parts:

Globe valve has following main parts:

Body
Bonnet
Internals/Trim/Wetted parts: Globe valve has following Wetted parts.
Disc
Seat Ring
Stem
Gland Bush


D) Pressure Class: Same as Gate valve.

E) Material: Same as Gate valve.

4.3 CHECK VALVE

-It is sometimes referred to as Non Return Valve.
-It is self-operated valve and allows the flow to pass in one direction and will not allow reverse flow.
-Installation of this valve is unidirectional.
-Flow direction is marked on the body.

A) Type and End Connection:

1) Lift Check Valve (up to 1 ½’’) : Socket Weld / Threaded / Butt Weld
2) Swing Check Valve ( >= 2’’) : Flanged / Butt Weld
3) Wafer type Check Valve: Wafer type / Wafer lug type. It is to be kept between two flanges.

B) Design & Dimension Standard:

BS 5352 : For Lift Check Valve
BS 1868 : For Swing Check Valve
API 594 :For Wafer Check Valve
ANSI/ASTM B 16.34 :For Pressure & Temperature limitation and Rating
ANSI/ASME B 16.10 : For Face to Face dimension
API 598 :For Testing of valve


D) Pressure Class: Same as Gate Valve

E) Material:

Lift Check Valve (up to 1.5” & SW / Threaded / BW): Same as forged Gate Valve
Swing Check Valve (>= 2’’& Flanged / BW): Same as cast steel Gate Valve
Wafer type Check Valve (Wafer type / Wafer lug type): Same as cast steel Gate Valve.

4.4 BALL VALVE

This valve is used for isolation & for quick on / off. It is mainly used in utility line i.e. cooling water, instrument air etc. and in hazardous and combustible fluid. Rotating the lever by 900 opens or closes this valves fully. Hence this valve is called quarter turn valve. Fire safe design as per API 607 is available for this valve. Installation of this valve is possible from both the ends. Hence it is bi-directional valve.

3-way and 4-way construction is possible in ball valve by providing “T” or “L” port in the ball.

A) End Connection:

Socket Weld & Threaded End – up to 1.5’’, 3-piece design
Flanged / Butt Weld- 2 piece design

B) Design & Dimension Standard:

BS 5351 For Ball Valves
ANSI/ASME B 16.10 For Face to Face dimension ANSI/ASTM B 16.34 For Pressure & Temperature limitation and Rating
API 598 For Testing of Valves

C) Main Parts:

Ball valve has following main parts.
Body
Ball valve has following internals.
Ball
Seat
Stem

D) Pressure Class: Same as Gate Valve

E) Material: Same as Gate Valve
Here Seat material is PTFE (Poly Tetra Fluoro Ethylene)

Fire safe valves are available as per API 607 & has following seats
Primary Soft Seat of PTFE
Secondary Metal to Metal Seat

4.5 BUTTERFLY VALVE

It is mostly used for isolation and in specific case used for regulation.
Regulation is not as precise as Globe Valve

A) End Connection: Same as Wafer check valve

Wafer type / Wafer lug type / Flange end/Butt end


B) Design & Dimension Standard:

API 609 For Butterfly valve
ANSI/ASME B 16.10 For Face to Face dimension
ANSI/ASTM B 16.34 For Pressure & Temperature limitation and Rating
API 598 For Testing of valve

C) Main parts:

Butterfly valve has following main parts:
Body
Butterfly valve has following internals:
Disc / Shaft / Seat

D) Pressure Class: Same as Gate Valve of cast steel type

E) Material: Same as cast steel Gate Valve
Seat Material: EPDM, Nitrile - These are one kind of Rubber, soft material
EPDM- Ethylene Propylene Di Monomer

4.6 PLUG VALVE

This valve is used for regulation, isolation and quick on / off in combustible or Hazardous fluid. 3-way and 4-way construction is possible in plug valve by providing “T” or “L” port in the plug.

A) End Connection:

Socket Weld/Threaded
Flanged/Butt Weld

B) Design & Dimension Standard:

BS 5353 For Plug valve
ANSI/ASME B 16.10 For Face to Face dimension
ANSI/ASTM B 16.34 For Pressure & Temperature limitation and Rating
API 598 For Testing of valves

C) Main Parts:

Plug valve has following main parts:
Body
Cover
Plug valve has following internals.
Stem
Plug
Sealant

D) Pressure Class: Same as Gate Valve

E) Material: Same as Gate Valve

4.7 CONTROL VALVE

These valves are self operated type. They have actuators. Actuators operate on the signal received from an instrument. They are used for very fine throttling and to have desired process parameters (pressure, temperature, flow) of fluid.

Control Valves can be of the following types based on parameters to be controlled:

· Pressure control valve-Receives signal from Pressure Indicator / Pressure Transmitter.
· Temperature control valve-Receives signal from Temperature Indicator/Temperature Transmitter
· Flow control valve-Receives signal from Flow Indicator/Flow Transmitter

There are two types of signal:

· Pneumatic – Valve has pneumatic actuator.(tubing is used)
· Electric – Valve has electrical (solenoid) actuator. (cables are used)

Based on construction, control valve has following types:

· Butterfly Valve
· Globe Valve
· Ball Valve

A) End Connection: Flanged End or BW. Flange end is always preferred because of regular servicing & maintenance.

B) Material: Same as other cast steel valves.

C) Design & Dimension Standard: Same as other valves.

D) Pressure Class: Same as other valves.

4.8 SAFETY VALVE

This valve is also known as Pressure relief valve. It is used for safe operation of plant. This valve releases excess pressure when it exceeds set pressure. Pressure is set by spring.

Inlet of this valve is one size lower or equal to the inlet pipe size. Outlet is at least one or more size higher to outlet pipe size.

A) Material & Pressure Class: Same as Gate Valve
Outlet Pressure class <= Inlet Pressure class
B) Main Parts:

Pressure safety valve has following main parts.
Body / Bonnet
Safety valve internals: Spring / Disc / Stem

C) Design & Dimension Standard: API 526: For Pressure & Temperature limitation and Rating and for Center to Face Dimension.


5 FASTENERS

It consists of Bolts, Full threaded Stud Bolts and Nuts.
Bolts have Hexagonal or Round head while Studs are without heads.
One stud with two nuts forms a set of fastener.
Fasteners are used for flange joints in piping to retain flanges and gaskets.
Threading is done on the studs and bolts by two methods.

1. Cut threads using cutting tool on Lathe.
2. Thread Rolling using rollers on thread rolling machine.

A) Design & Dimension Standard:

ANSI/ASME B 16.5 For Studs (Length & Diameter)

ANSI/ASME B 18.2.1 For thread types with details of Studs & Bolts

ANSI/ASME B 18.2.2 For Nuts

B) Material:

(1) CS : ASTM A 193 Gr B7 : For Stud,

ASTM A 194 Gr 24 : For Nut

(2) LTCS : ASTM A 320 Gr L7 : For Stud,

ASTM A 194 Gr 4 : For Nut

(3) LAS : ASTM A 193 Gr B16 : For Stud,

ASTM A 194 Gr 4 : For Nut ,

(4) SS : ASTM A 193 Gr B8 : For Stud,

ASTM A 194 Gr 8 : For Nut.

6 GASKETS

Gaskets are used to avoid Static leakage and metal to metal contact.
There are two types of gaskets from material point of view.

1. Metallic Gasket:

Metal is used in the construction of Gasket either as main
material or as reinforcing material..

e.g. Spiral wound gasket.

Used with RF flanges up to 600 rating.

Thickness of spiral wound gasket is 4.5 mm.

Ring joint Gasket used with RJ flanges from 900 rating.

2. Non-metallic Gasket:

Metal is not used in the construction of gaskets.
e.g. Flat Gasket
Thickness of this gasket is normally 2 to 3 mm.
It is used in FF and T&G type of flange.




A) Design & Dimension Standard:

ANSI/ASME B 16.20 For Metallic Gaskets
ANSI/ASME B 16.21 For Non-metallic Gaskets

B) Material:

For Metallic Gasket

(1) S.S. ring for ring joint gasket.
(2) Spiral wound Gasket

(a) S.S. (as reinforcement) & for inner and outer (centering) ring.

(b) Filler material as follows.

Graphite used for high temperature.
PTFE used for low temperature.
CAF – It is banned to use from health hazard point of view.

For Non-metallic Gasket

(1) Flat Gasket

(a) CAF (Compressed Asbestos Fiber)- It is banned to use from health hazard
point of view.
(b) PTFE
(c) Graphite

PIPING CODES & STANDARDS

The following codes and standards shall be used together with this standard specification for
materials, design and dimensional requirements.

American National Standard Institute (ANSI)
American Society of Mechanical Engineers (ASME)

ASME B 31.1 - Power piping

ASME B 31.3 - Process Piping for Petroleum refineries, Chemical,
Pharmaceutical, Textile, Paper, Semiconductor & Cryogenic plant

ASME B 31.4 - Piping generally used for transporting & distributing liquid Hydrocarbons & other liquids

ASME B 31.5 - Refrigeration piping

ASME B 31.8 - Piping generally used for transporting & distributing Gases.

ASME B 31.9 - Building services

ASME B 31.11 - Slurry transportation piping system

ASME B 16.5 - Pipe Flanges and Flanged Fittings NPS ½ Trough NPS 24

ASME B 16.9 - Factory-Made Wrought Steel Buttwelding Fittings

ASME B 16.10 - Face-to-Face and End-to-End Dimensions of Valves

ASME B 16.11 - Forged Fittings, Socket- Welding and Threaded

ANSI B 16.14 - Ferrous Pipe Plugs, Bushing and Locknuts with Pipe Threads

ASME B 16.20 - Metallic Gaskets for Pipe Flanges- Ring-Joint, Spiral- Wound, and Jacketed
ASME B 16.21 - Nonmetallic Flat Gaskets for Pipe Flanges

ASME B 16.25 - Buttwelding Ends

ASME B 16.28 - Wrought Steel Buttwelding Short Radius Elbows

ASME B 16.34 - Valves - Flanged, Threaded, and Welding End

ASME B 16.36 - Orifice Flanges

ASME B 16.47 - Large Diameter Steel Flanges NPS 26 Through NPS 60

ANSI B 18.2.1 - Square and Hex Bolts and Screws (Inch Series)

ANSI B 18.2.2 - Square and Hex nuts (Inch Series)

ASME B 36.10M - Welded and Seamless Wrought Steel Pipe

ASME B 36.19M - Stainless Steel Pipe

American Petroleum Institute (API)

API SPEC 5L - Specification for Line Pipe

API STD 594 - Check Valves: Wafer, Wafer-Lug, and Double Flanged Type

API STD 598 - Valve Inspection and Testing

API STD 600 - Steel Gate Valves- Flanged and Butt-welding Ends,
Bolted and Pressure Seal Bonnets

API STD 602 - Compact Steel Gate Valves- Flanged, Threaded, Welding, and Extended Body Ends

API STD 609 - Butterfly Valves: Double Flanged, Lug-and wafer Type


Manufacturers standardizations society-standard practice

MSS SP-6 : Standard Finishes for Contact Faces of Pipe Flanges and
Connecting-End Flanges of Valves and Fittings

MSS SP-25 : Standard Marking Systems for Valves, Fittings, Flanges & Union

MSS SP-45 : Bypass and Drain Connections

MSS SP-61 : Pressure Testing of Steel Valves

MSS SP-67 : Butterfly Valves

MSS SP-75 : Specification for High Test Wrought Butt Welding Fittings

MSS SP-82 : Valve Pressure Testing Methods

MSS SP-95 : Swadged Nipples and Bull Plugs

MSS SP-97 : Integrally Reinforced Forged Branch Outlet Fittings-
Socket welding, Threaded and Buttwelding Ends

American Society for Testing and Materials (ASTM)

ASTM Section II A Volume 1 & 2

ASTM Section V

ASTM Section VIII Division 1 & 2

British Standards (BS)

BS 5351 - Steel ball valves for petroleum, petrochemical & allied industries

BS 5352 - Specifications for steel wedge gate, globe & check valves 50 mm & smaller for petroleum, petrochemical & allied industries

BS 5353 - Steel plug valves

BS 1873 - Steel globe & globe stop & check valves (Flanged & butt-welded ends) for petroleum, petrochemical & allied industries

BS 6755 (Part 1&2) - Testing of Valves

CLASSIFICATION OF PUMPS

CLASSIFICATION OF PUMPS

How are pumps classified?

1. Applications they serve
2. The materials of construction
3. The liquid they handle
4. Their orientation in space

Types of Pumps:

General Choice
• Centrifugal
• Rotary
• Reciprocating

1 OH1 Foot mounted

2. OH2 Centerline mounted

3. OH3 (Inline flexibly coupled), OH4 (Inline Rigidly coupled), OH5 & OH6 (Inline closed coupled)

4. BB1 (Axial split 1 & 2 stage)

5. BB2 (Radial split 1 & 2 stage)

6. BB3 (Multistage axial split)

7. BB4 & 5 (Multistage radial split)

8. VS 4 & 5 (Sump Pump)

9. Reciprocating types can be Piston, Plunger or Diaphragm type

10. Rotary type can be Single rotor (vane, piston, flexible member, screw etc) or Multiple rotor type (gear, lobe, circumferential piston, or screw).

11. External and Internal Gear pumps

SOME IMPORTANT QUESTIONS......

1. Are centrifugal pumps variable speed?
Most centrifugal pumps do not have variable speed motors. However, you can control flow rate on the discharge using a valve.


2. What exactly is a positive displacement pump?
A positive displacement pump emits a given volume of fluid for each revolution of the motor. Bellows, double-diaphragm, flexible impeller, gear, oscillating, piston, progressing cavity, rotary lobe, rotary vane, and peristaltic pumps are all positive displacement pumps.


3. Which pumps can I run dry?
Peristaltic, piston pumps with ceramic heads, bellows pumps, and diaphragm pumps can be run dry for any length of time. Centrifugal, rotary vane, and gear pumps should not be run dry; exceptions are if the gear or impeller is made of a self-lubricating material such as RYTON in which case the pump can be run for a few minutes while priming.


4. What is the maximum viscosity rating for pumps?
This depends on the type of pump and the specific pump. Diaphragm pumps (especially double diaphragm pumps) and gear pumps are usually the best for viscous fluids.

How do pumps work?

Pumps move fluid in a variety of ways

1. Centrifugal Pumps - Use centrifugal force to push the fluid through the outlet.

2. Metering Pumps - Bellows, diaphragm, peristaltic, piston, and syringe pumps are all metering pumps that pull the fluid through the inlet valve into a chamber, close the inlet valve, and then push the fluid through the outlet valve.

3. Positive Displacement Pumps - Bellows, double-diaphragm, flexible impeller, gear, oscillating, piston, progressing cavity, rotary lobe, rotary vane, and peristaltic pumps have a fixed cavity that the fluid is pushed through by rollers, gears, or impeller. As the fluid is pushed through, it leaves a void or vacuum which pulls in more fluid.

LIQUID PUMP TERMINOLOGY

Cavitation—Process in which small bubbles are formed and implode violently; occurs when NPSHa < NPSHr.
Dead Head—The ability of a pump to continue running without damage when discharge is closed off. Only recommended for centrifugal pumps.
Density (specific weight of a fluid)—Weight per unit volume, often expressed as pounds per cubic foot or grams per cubic centimeter.
Flooded Suction—Liquid flows to pump inlet from an elevated source by means of gravity. Recommended for centrifugal pump installations.
Flow—A measure of the liquid volume capacity of a pump. Given in gallons per hour (GPH), gallons per minute (GPM), liters per minute (L/min), or milliliters per minute (mL/min).
Fluids—Include liquids, gases, and mixtures of liquids, solids, and gases. In this catalog, the terms fluid and liquid are both used to mean a pure liquid or a liquid mixed with gases or solids that acts essentially like a liquid in pumping applications.
Head—A measure of pressure, expressed in feet of head for centrifugal pumps. Indicates the height of a column of water being moved by the pump (without friction losses).
Pressure—The force exerted on the walls of a tank, pipe, etc., by a liquid. Normally measured in pounds per square inch (psi).
Prime—Charge of liquid required to begin pumping action when liquid source is lower than pump. Held in pump by a foot valve on the intake line or by a valve or chamber within the pump.
Seals—Devices mounted in the pump housing and/or on the pump shaft that prevent leakage of liquid from the pump.
Self-Priming—Pumps that draw liquid up from below pump inlet (suction lift), as opposed to pumps requiring flooded suction.
Specific Gravity—The ratio of the weight of a given volume of liquid to pure water. Pumping heavy liquids (specific gravity greater than 1.0) will require more drive horsepower.
Static Discharge Head—Maximum vertical distance (in feet) from pump to point of discharge with no flow.
Strainer—A device installed in the inlet of a pump to prevent foreign particles from damaging the internal parts.
Sump—A well or pit in which liquids collect below floor level; sometimes refers to an oil or water reservoir.
Total Head—Sum of discharge head, suction lift, and friction loss.

Valves:
· Bypass Valve—Internal to many pump heads that allow fluid to be recirculated if a given pressure limit is exceeded.
· Check Valve—Allows liquid to flow in one direction only. Generally used in discharge line to prevent reverse flow.
· Foot Valve—A type of check valve with a built-in strainer. Used at point of liquid intake to retain liquid in system, preventing loss of prime when liquid source is lower than pump.
· Relief Valve—Used at the discharge of a positive displacement pump. An adjustable, spring-loaded valve opens when a preset pressure is reached. Used to prevent excessive pressure buildup that could damage the pump or motor.

Viscosity—The "thickness" of a liquid or its ability to flow. Most liquids decrease in viscosity and flow more easily as they get warmer.

Welcome !!!!!!

Hi,Freinds

This is Dhananjay.Created this blog for Piping and Rotating Equipment people. I will try to give you all possible information about piping and rotating equipments. Wish me a good start and suggest me something usefull.

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