2. Valves
Piping Department
Valve – An integral part of the piping system
Classified on the basis of
a) Valve function/action
- On/off (stopping or starting flow)
- Regulating (varying the rate of flow)
- Checking (permitting flow in one direction only)
b) Operation
- Manual/Auto operation (e.g. Ball, globe, gate, butterfly,
needle)
- Self operation (e.g. Check valve)
The internal elements of a valve are collectively referred to as a
Valve Trim. The trim typically includes a disk, seat, stem, and
sleeves needed to guide the stem.
3. Valve components
Piping Department
The basic parts that make up a valve
are:-
a) The DISC - The moving part directly
affecting the flow irrespective of its
shape.
b) The SEAT - The non moving part the
disc rests on.
c) The PORT - is the maximum internal
opening for flow (that is when the valve
is fully open).
d) The STEM - in case of manual
operated valve, disc is actuated by the
stem. Two types –
a) Rising stem (e.g.. Gate, globe)
b) Non rising/rotating stem (e.g. ball,
butterfly)
4. Valve components
Piping Department
e) The BONNET - three types
a) Screwed - For services where there is no harm to personnel. More
suitable for small valves requiring frequent dismantling.
b) Bolted - Frequently used in hydrocarbon applications. For moderate
pressures and to facilitate frequent cleaning and inspection.
c) Breech-lock - The breech-lock is a heavier infrequently used are more
expensive construction, also for high pressure use and involves seal
welding of the bonnet with the body.
f) LANTERN RING - As an option the bonnet may include a ‘lantern ring’
which serves two purposes –
a) either to act as a collection point to drain off any hazardous seepages,
b) or as a point where lubricant can be injected.
5. Piping Department
Gate Valve
• A gate valve is a valve that opens
by lifting a round or rectangular
gate/wedge out of the path of the
fluid.
• Gate valves are sometimes used
for regulating flow, but many are not
suited for that purpose, having been
designed to be fully opened or
closed. When fully open, the typical
gate valve has no obstruction in the
flow path, resulting in very low
friction loss.
6. Piping Department
• Gate valves are characterized as having either a rising or a non-rising
stem.
• Rising stems provide a visual indication of valve position.
• Non-rising stems are used where vertical space is limited or
underground.
Gate Valve
7.
8. Piping Department
Globe Valve
• A Globe valve is a type of valve used for regulating flow in a pipeline,
consisting of a movable disk-type element and a stationary ring seat in a
generally spherical body .
• Globe Valves are named for their spherical body shape with the two
halves of the body being separated by an internal baffle.
• Automated globe valves have a smooth stem rather than threaded and
are opened and closed by an actuator assembly.
• When a globe valve is manually operated, the stem is turned by a hand
wheel.
9.
10.
11. Ball Valves - Introduction
Piping Department
• Ball valves are flow valves that are quarter-turn
• These valves allow for shut-off and/or purposes of control.
• A ball valve is a valve that opens by turning a handle attached to a ball
inside the valve.
• The ball has a hole, or port, through the middle so that when the port is in
line with both ends of the valve, flow will occur.
• When the valve is closed, the hole is perpendicular to the ends of the
valve, and flow is blocked.
12.
13.
14. Ball Valves – Types
Full port, Standard port & Reduced port
Piping Department
• A full port ball valve has an over sized ball so that the
hole in the ball is the same size as the pipeline resulting
in lower friction loss. Flow is unrestricted, but the valve is
larger.
• A standard port ball valve is up to one pipe size
smaller than nominal pipe size but still has a significantly
better flow than globe valve. Usually less expensive.
• A reduced port ball valves have more than one pipe
size flow restriction and are not recommended in building
services piping, but rather for process piping in
hazardous material transfer.
15. Ball Valves – Types
V-Port Ball Valve
Piping Department
• A v port ball valve has either a 'v' shaped
ball or a 'v' shaped seat.
• This allows the orifice to be opened and
closed in a more controlled manner with a
closer to linear flow characteristic.
• Linear flow characteristic produces
equal change in flow per unit of valve stroke,
regardless of the position of the valve.
• When the valve is in the closed position
and opening is commenced the small end of
the ‘v' is opened first allowing stable flow
control during this stage.
16. Ball Valves – Types
One piece, Two piece and Three piece
Piping Department
• One piece ball valves are almost always reduced bore(thus significant
pressure drop), are relatively inexpensive and generally are throw-away. Have
no potential body leak path.
• Two piece ball valves are generally slightly reduced (or standard) bore, they
can be either throw-away or repairable. Best price value.
• The 3 piece design allows for the center part of the valve containing the
ball, stem & seats to be easily removed from the pipeline. This facilitates
efficient cleaning of deposited sediments, replacement of seats and gland
packing's, polishing out of small scratches on the ball, all this without removing
the pipes from the valve body. The design concept of a three piece valve is for
it to be repairable.
17.
18.
19. Piping Department
• Three-way ball valves have an L-
or T-shaped hole through the
middle.
• Multi port ball valves with 4 or
more ways are also commercially
available, the inlet way often being
orthogonal to the plane of the
outlets.
• This valve has two L-shaped
ports in the ball that do not
interconnect, sometimes referred to
as an "x" port.
Ball Valves – Types
Two way & three way ball valves
20. Piping Department
Ball Valves – Applications
Ball valves have many good points and are often considered superior to
many other kinds of valves.
• Ball valves are very easy to use and can both maintain and regulate three
things
-high pressure
-high volume and
-high flow of temperature.
• Other advantages of ball valves are that they are sturdy devices that can
be purchased for a low price and they have a long service life.
• An added plus is that the regulating element's design makes it easy for
the ball valve to work without concern about side loads, which often plague
globe or butterfly valves.
• The ball valve design allows for the easy ability to fix the seats if a
problem arises and also seals without having to take away the body of the
valves from the line.
21. Piping Department
Ball Valves – Applications
• Ball valves are durable and usually work to achieve perfect shutoff even
after years of disuse.
• They are therefore an excellent choice for shutoff applications (and are
often preferred to globe valves and gate valves for this purpose). They do
not offer the fine control that may be necessary in throttling applications but
are sometimes used for this purpose.
• Ball valves are used extensively in industry because they are very
versatile, pressures up to 10,000 psi, temperatures up to 200 Deg C. Sizes
from 1/4" to 12" are readily available They are easy to repair, operate
manually or by actuators.
• Ball valves are to be found being used in a number of different industries.
• Some of these include the chemical, oil, pharmaceutical, allied process
and also services such as corrosive and cryogenic.
22. Piping Department
Butterfly Valves – Introduction
• A butterfly valve is a type of flow control device, typically used to
regulate a fluid flowing through a section of pipe.
• A flat circular plate is positioned in the center of the pipe. The plate has a
rod through it connected to an actuator on the outside of the valve.
Rotating the actuator turns the plate either parallel or perpendicular to the
flow.
• Unlike a ball valve, the plate is always present within the flow, therefore
a pressure drop is always induced in the flow regardless of valve position.
• A butterfly valve is from a family of valves called quarter-turn valves.
23. Piping Department
Butterfly Valves – Types
TYPES
• Resilient butterfly valve which has a flexible rubber seat. Working pressure
232 PSI. The resilient butterfly valve, which uses the flexibility of rubber, has
the lowest pressure rating.
• High performance butterfly valve which is usually double eccentric in
design. Working pressure up to 725 PSI. The high performance butterfly
valve, used in slightly higher-pressure systems, features a slight offset in the
way the disc is positioned, which increases the valve's sealing ability and
decreases its tendency to wear.
• Tricentric butterfly valve which is usually with metal seated design.
Working pressure up to 1450 PSI.
• The valve best suited for high-pressure systems is the tricentric
butterfly valve, which makes use of a metal seat, and is therefore able to
withstand a greater amount of pressure.
24.
25. Piping Department
Butterfly Valve - Mounting Schemes
BUTTERFLY VALVE MOUNTING SCHEMES
Wafer Style Butterfly Valves - The wafer style butterfly valve is installed
between two flanges. The valve is kept in place by using bolts or studs and nuts
from flange to flange. This type of installation, of course, makes it impossible to
disconnect just one side of the piping system from the valve. That is where the
lug style valve comes in.
Lug Style Butterfly Valves - Lug style valves have threaded inserts at both
sides of the valve body. This allows them to be installed into a system using two
sets of bolts and NO nuts. The valve is installed between two flanges using a
separate set of bolts for each flange. This setup permits either side of the piping
system to be disconnected without disturbing the other side.
A lug style butterfly valve used in dead end service generally has a reduced
pressure rating. For example a lug style butterfly valve mounted between two
flanges has a 150 psi pressure rating. The same valve mounted with one flange,
in dead end service, has a 75 psi rating.
26.
27. Piping Department
Butterfly Valve - Applications
• Butterfly valves are commonly used as control valves in applications
where the pressure drops required of the valves are relatively low.
• Butterfly valves can be used in applications as either shutoff valves
(on/off service) or as throttling valves (for flow or pressure control).
• Typical uses would include isolation of equipment, fill/drain systems,
bypass systems, and other like applications where the only criteria for
control of the flow/pressure is that it be on or off.
• Two special applications for a butterfly valve include the use of a valve for
free discharge and the use of a butterfly valve for flashing or choking
cavitation.
(Cavitation is defined as the phenomenon of formation of vapour bubbles of a
flowing liquid in a region where the pressure of the liquid falls below its vapour
pressure)
28. Piping Department
Check Valve - Introduction
• A check valve, clack valve, non-return valve or one-way valve is a mechanical
device, a valve, which normally allows fluid (liquid or gas) to flow through it in
only one direction.
• Check valves work automatically and most are not controlled by a person or
any external control; accordingly, most do not have any valve handle or stem.
• An important concept in check valves is the cracking pressure which is the
minimum upstream pressure at which the valve will operate.
• Typically the check valve is designed for and can therefore be specified for a
specific cracking pressure.
30. Piping Department
Check Valve - Applications
• Pumps commonly use inlet and outlet ball check valves.
• Check valves are used in many fluid systems such as those in chemical,
and power plants, and in many other industrial processes.
• Check valves are also often used when multiple gases are mixed into one
gas stream. A check valve is installed on each of the individual gas streams to
prevent mixing of the gases in the original source.
31.
32.
33. Piping Department
Valves – Design Code & MOC
• Design Code - ASME B 16.34 (Valves-Flanged, Welded and Threaded
End)
• Material of Construction - Valves are made using an assortment of
materials, some of which include
- Carbon steel
- Stainless steels
- Alloy steel
• Valve Inspection, Testing - API 598 covers the testing and
inspection requirements for gate, globe, check, ball, plug & butterfly
valves.
34. Piping Department
Valve Type & Service
Final Comparison
VALVE TYPE SERVICE
BALL General type valve, Used for all fluids.(On/Off)
GATE Usually, used for Liquid (On/Off), never used for flow rate control
(Knife Gate type used for Low pressure, Liquid Mud)
GLOBE Used for flow rate control (Small diameter Utility connection etc.)
CHECK Used for prevention of back flow
NEEDLE It’s a Small Size, used for flow rate control certainly, compare with others.
BUTTERFLY It has not Compact, easy to operate, so that used for Firewater, Bulk line, usually.
MODULAR It has Double Block & Bleed function, so that used for Branch line of High pressure
Instrument.
PLUG Used for fluid include solid body, like a sand, Used for High pressure valve in
Wellhead
35. Piping Department
Valve Material & Specificity
CS VALVE MATERIAL
Classification CS (high temp.) LTCS ( low temp.)
Forging Casting Forging Casting
B
O
D
Y
Material Code ASTM A105(N) ASTM A216 ASTM A350 ASTM A352
Using Grade - WCB LF2/LF3 LCC
Min.Y.S. (ksi) 35 36 35 40
Min.T.S. (ksi) 60 70 60 70
Impact Test
(Aver. J/deg.)
N/A N/A 18J/-50F 20J/-50F
Chem.
Content
C
S
CE
0.3
0.035
NA (0.5 :S5)
0.3
0.045
N/A
0.3
0.025
NA
0.25
0.045
NA ( 0.55:S23)
Trim Material A182 F316, A182 F6A(13 Cr.)
Stellite-6 hard facing
A564 Gr.630(Age hardening),
A182 F316, A564 Gr.630, Stellite-6
Bolt/Nut Material A193-B7/A194-2H A320-L7/A194-7
Seat Material PEEK/PTFE PEEK/R-PTFE
Seal/Packing Viton, Teflon, Graphite Viton, Teflon, Graphite
36. Piping Department
Valve Material & Specificity
SS VALVE MATERIAL
Classification Stainless Steel Duplex Stainless Steel
Forging Casting Forging Casting
B
O
D
Y
Material Code ASTM A182 ASTM A351 ASTM A182 ASTM A890
Using Grade F316/ F316L CF8M F51 4A
Min.Y.S. (ksi) 30/25 30 65 60
Min.T.S. (ksi) 75/70 70 90 90
Chem.
Content
Ni
Cr
C
S
Mo
10-14
16-18
0.08/0.035
0.03
2-3
9-12
18-21
0.08
0.04
2-3
4.5-6.5
21-23
0.03
0.02
2.5-3.5
4.5-6.5
21-23.5
0.03
0.02
2.5-3.5
Trim Material A182 F316, A182 F XM-19(22Cr,13Ni)
,Stellite-6 hard face, A479 316 (ENP),
A182 F51, Stellite-6 hard facing
A479 S31803
Bolt/Nut Material A193-B7/A194-2H, A193-B8M/A194-8M A320-L7/A194-7, A182 F51/F55
Seat Material PEEK, /RPTFE PEEK, R-PTFE
Sael/Packing Viton, Teflon, Graphite Viton, Teflon, Graphite
37. Piping Department
Valve Material & Specificity
ALLOY STEEL VALVE MATERIAL
Classification Ni-Al-bronze (for Cu-Ni) Titanium
B
O
D
Y
Material Code ASTM B148(Casting) ASTM B381(Titanium forging)
ASTM B367 (Titanium Casting)
Using Grade UNS C95800 F2(Forging), C2(Casting)
Min.Y.S. (ksi) 35 40
Min.T.S. (ksi) 85 50
Chemical
Content
Cu: 81.3%
Ni: 4.5%
Iron: 4%
Al: 9.5%
C: 0.03
Iron 0.25
Ti: app.99%
Trim Material ASTM B151 UNS C70600
A182 F316 AISI 316
ASTM B381- F2
Bolt/Nut Material A193-B8M/A194-8M ASTM F467/468 Gr.5 or 9
Seat Material PEEK / PTFE PTFE
Sael/Packing Viton, Teflon, Graphite Viton, Teflon, Graphite
38. Piping Department
Ball Valve Specification
CLASSIFICATION ASME or API BS or EN
Design Standard API 6D, API 608
ASME B16.34 (Pressure Temp. Rating )
BS 5351
EN 13547 ( Al-Bronze valve)
Face to Face
dimension
API 6D
ASME B16.10 (long Pattern)
BS EN 558 Part 2
Housing Design One Piece Body or Split Body (2 piece, 3 piece) , Side or Top entry
Seat Arrangement Floating Type: L.P. & small size (ex: 150/300#:<12”, 600/900#;<8”, 1500/2500#:<4”)
Trunnion type: H.P. & large size (ex: 150/300#:>=12”, 600/900#;>=8”,
1500/2500#:>=4”)
Bore Type RB: Reduced Bore, FB: Full Bore
Operator Lever: L.P. & small size (ex: 150/300#:<12”, 600/900#;<8”, 1500/2500#:<4”) ,
Gear Operate: H.P. & large size (ex: 150/300#:>=12”, 600/900#;>=8”, 1500/2500#:>=4”)
Actuator : Electric Actuator, Hydraulic Actuator, Pneumatic Actuator
Pressure rating ASME B16.34 (150#,300#....2500#) EN13547 (PN20,PN50… PN420)
Fire Test Cert. API 6FA, ISO-10497, API 607
Body/Seat Hyd. Test API 6D, ISO 5208 BS EN 12266 Part-1
Leakage Rate ISO 5208 Rate “A” BS EN 12266 Part-1 Rate “A”
Locking Device - Car Seal or Pad Lock (ASTM F993), - Mechanical Inter-locking device
39. Piping Department
Gate Valve Specification
CLASSIFICATION ASME or API BS or EN
Design Standard API 602 : for size <=2”
API6D, API 600 (Style B): for size >=2”
BS 5352: SW, FNPT
BS 1414: Flanged
Face to Face
dimension
API 6D, ASME B16.10 BS 1414
BS 5154
Housing Design -Regular type with OS&Yoke, solid disc, bolted bonnet/grand Rising stem
- Knife edge gate.
Seat Arrangement Renewable metal seat
Integral seat with hard facing.
Operator Hand wheel
Pressure rating API 800# ; for size <=2”
ASME B16.34 (#150, #300…)
EN13547 (PN20,PN50… PN420)
Cl. 800#
Fire Test Cert. ISO 10497 ( type approval)
Body/Seat Hyd. Test
& Leakage Rate
API 598
ISO 5208, Rate ”A”
BS/EN 12266 Part-1
40. Piping Department
Globe Valve Specification
Classification ASME or API BS or EN
Design Standard ASME B16.34, API 600 BS 1873: Flanged,
BS 5352 :SW, FNPT
Face to Face
dimension
ASME B16.10 BS EN 588 Part-2: Flanged
BS 5352: SW, FNPT
Housing Design Regular type with outside screw and yoke, solid disc, bolted bonnet/grand
Seat Arrangement Renewable seat,
Integral seat with hard facing.
Operator Hand wheel
Pressure rating ASME B16.34 (150#, 300#....),
API 800#: for size <=2”
EN13547 (PN20,PN50… )
Cl.800
Fire Test Cert. ISO 10497
Body/Seat Hyd. Test API 598 BS EN 12266 Part-1
Leakage Rate API 598 BS EN 12266 Part-1, Rate ”B”
41. Piping Department
Check Valve Specification
Classification ASME or API BS or EN
Design Standard Swing Check: API 6D/ASME B16.34
Dual Plate : API 594 / ASME B16.34
Piston : ASME B16.34
Swing Check: BS 1868
Piston :BS EN 15761 Flange,
BS 5352;SW,FNPT
Face to Face
dimension
ASME B16.10/API 6D: Swing Type
API 594 : Dual Plate type
BS 2080 ( for size <=1.5”)
Housing Design Swing: Straight pattern, Piston: Bolted Bonnet, Dual plate: lugged Wafer
Seat Arrangement Swing/Dual Plate: Metal to Metal, Piston: Spring loaded ball/piston, renewable
Operator Not Applicable
Pressure rating ASME B16.34 (150#,300#,...)
API #800: for size <=2”
EN13547 (PN20,PN50…)
Cl.800#
Fire Test Cert. ISO 10497
Body/Seat Hyd. Test ISO 5208:swing check
API 598:dual plate check
ISO 5208: swing
BS EN 12266 part-1: piston
Leakage Rate ISO 5208 Rate”A”: swing check
API 598 table-5, rate”C”: dual plate
ISO 5208 rate”A”: swing
BS EN 12266 part-1 Rate ”B”: piston
42. Piping Department
Needle Valve Specification
Classification ASME or API BS or EN
Design Standard ASME B16.34 BS 1873
Face to Face
dimension
ASME B16.10 BS 2080
Housing Design Manufacturer standard
Seat Arrangement Integral or Renewable seat
Operator Hand Wheel
Pressure rating API #800, #3000, #6000
Fire Test Cert. ISO 10497
Body/Seat Hyd. Test BS EN 12266 Part-1
Leakage Rate BS EN 12266 Part-1 rate ”A”
43. Piping Department
Butterfly Valve Specification
Classification ASME or API BS or EN
Design Standard API 609 Category-A or B BS 5155
Face to Face
dimension
API 609 Table-2 BS 5155
Housing Design Wafer Type ( Lug Type ,Fully Lug type), Flange Type
Seat Arrangement Renewable
Operator Hand wheel: small size (ex: Up to 6”size) ,
Gear Operate: large size (ex: 8” and above)
Actuator : Electric Actuator, Hydraulic Actuator, Pneumatic Actuator
Pressure rating ASME B16.34 (150#,300#...)
Fire Test Cert. ISO 10497, API 6FA,
Body/Seat Hyd. Test API 598
Leakage Rate API 598 Table-5
44. Piping Department
Data Sheets
LINE SIZE
MATERIAL • Body Material
• Trim Material
• Seat Material
• Gasket Material
• Bolt/Nut Material.
OPERATOR • Hand Wheel
• Gear Operated
• Chain Operated
• Lever Operated
SEAT ARRANGEMENT • Integral
• Renewable
CONSTRUACTION
FEATURES
• Reduced Port, Standard Port or Full Port.
• One piece, Two Piece or Three Piece.
• Stem – Rising/Non Rising/Rotating
• Bonnet – Screwed, Bolted or Breechlock.
• Mounting System – Lug or Wafar type
PRESSURE RATING
47. What are Steam
Traps?
The duty of steam trap is to remove the condensate and non
condensable
gases from the steam main line It must involve negligible
consumption or loss
of live steam.
An example:
Without steam traps being used condensate would form in the
distribution
piping, creating a wide range of problems. Steam would enter a set of
tubes or
a coil at one end and come out at the other end as either steam,
condensate or
a two-phase mixture of the two; very dangerous, damaging and
wasteful.
Piping Department
48. Uses
• Thus by installing steam traps in strategic locations throughout the
distribution system we can eliminate those problems. With proper
placement and specification of steam traps we can create and
maintain an efficient, cost effective steam supply and distribution
system
The three important functions of steam traps are:
• - Discharge condensate as soon as it is formed.
• - Have a negligible steam consumption.
• - Have the capability of discharging air and other non-condensable
gases.
Piping Department
Steam
Traps
49. Types of Steam Traps
a) THERMOSTATIC b) MECHANICAL c) THERMODYNAMIC
TEMPERATURE DENSITY KINETIC ENERGY
Piping Department
50. a) Mechanical Steam
Traps
• It works on the principle of the difference in density between
steam and condensate.
• This trap is made up of mechanical apparatus that is driven by the
density of condensate to operate a float or a bucket.
• It has a float that rises and falls in relation to condensate level and
this usually has a mechanical linkage attached that opens and
closes the valve. Mechanical traps operate in direct relationship to
condensate levels present in the body of the steam trap.
• They can continuously pass large volumes of condensate and are
suitable for a wide range of process applications.
Piping Department
51. Types of Mechanical Stream
Traps
• Float and thermostatic type(ball float type)
• Inverted Bucket type
Piping Department
53. Advantages
• The trap continuously discharges condensate at steam temperature. This makes it the first choice
for applications where the rate of heat transfer is high for the area of heating surface available.
• It is able to handle heavy or light condensate loads equally well and is not affected by wide and
sudden fluctuations of pressure or flow rate.
• As long as an automatic air vent is fitted, the trap is able to discharge air freely.
• It has a large capacity for its size.
Piping Department
54. Disadvantag
es
• Although less susceptible than the inverted bucket trap, the float type trap can be damaged by
severe freezing and the body should be well lagged.
• As with all mechanical type traps, different internals are required to allow operation over varying
pressure ranges. Traps designed to operate on higher differential pressures have smaller orifices
to balance the bouyancy of the float. If a trap is subjected to a higher differential pressure than
intended, it will close and not pass condensate.
Piping Department
55. Mechanical Stream
Traps
Inverted bucket steam trap
• Most widely used
trap in the industry.
• There aren't
necessarily situations
where this type of trap
wouldn’t work but
rather situations
where a less
expensive, smaller,
possible long lasting
type of trap cold have
been applied.
(ii) the arrival of steam causes
the bucket to become buoyant,
it then rises and shuts the
outlet.
In (ii), air reaching the trap at
start-up will also give the bucket
buoyancy and close the valve.
The bucket vent hole is
essential to allow air to escape
into the top of the trap for
eventual discharge through the
main valve seat. The hole, and
the pressure differential, are
small so the trap is relatively
slow at venting air. At the same
time it must pass (and therefore
waste) a certain amount of
steam for the trap to operate
once the air has cleared. A
parallel air vent fitted outside
the trap will reduce start-up
times.
(i) The bucket hangs down, pulling
the valve off its seat. Condensate
flows under the bottom of the
bucket filling the body and flowing
away through the outlet.
(iii) the trap remains shut until the
steam in the bucket has condensed
or bubbled through the vent hole to
the top of the trap body. It will then
sink, pulling the main valve off its
seat. Accumulated condensate is
released and the cycle is repeated.
Piping Department
56. Advantages
• The inverted bucket steam trap can be made to withstand high pressures.
• Like a float-thermostatic steam trap, it has a good tolerance to waterhammer conditions.
• Can be used on superheated steam lines with the addition of a check valve on the inlet.
• Failure mode is usually open, so it's safer on those applications that require this feature, for
example turbine drains.
Piping Department
57. Disadvantag
es
• The small size of the hole in the top of the bucket means that this type of trap can only discharge
air very slowly. The hole cannot be enlarged, as steam would pass through too quickly during
normal operation.
• There should always be enough water in the trap body to act as a seal around the lip of the
bucket. If the trap loses this water seal, steam can be wasted through the outlet valve.
• Like the float trap, the orifice in an inverted bucket trap is designed to operate up to a maximum
differential pressure. If the trap is subjected to a higher differential pressure thanintended, it will
close and not pass condensate.
Piping Department
58. b) Thermostatic Steam
Traps
• This type of trap operates on the principle of expanding liquids
and metals.
• They have a valve that is driven on / off the seat by either
expansion / contraction caused by
temperature change.
• They differ from mechanical traps in that their design requires
them to hold back some condensate waiting for it to cool
sufficiently to allow the valve to open.
• In most circumstances this is not desirable as condensate needs to
be removed as soon as it is formed.
Piping Department
61. Advantage
s
• Bimetallic steam traps are usually compact, yet can have a large condensate capacity.
• The valve is wide open when the steam trap is cold, giving good air venting capability and
maximum condensate discharge capacity under 'start-up' conditions
• Bimetallic steam traps are usually able to withstand waterhammer, corrosive condensate, and
high steam pressures.
• The bimetal elements can work over a wide range of steam pressures without any need for a
change in the size of the valve orifice.
Piping Department
62. Disadvantag
es
• As condensate is discharged below steam temperature, waterlogging of the steam space will
occur unless the steam trap is fitted at the end of a long cooling leg, typically 1 - 3m of unlagged
pipe (see Fig. 11.2.14). Bimetallic steam traps are not suitable for fitting to process plants where
immediate condensate removal is vital for maximum output to be achieved.
• Bimetallic steam traps do not respond quickly to changes in load or pressure because the
element is slow to react.
Piping Department
63. Thermostatic Steam
Traps
Liquid Expansion Type
• Thermal expansion traps contain a thermostatic element that is filled with oil.
• As the oil heats up and expands, it causes a piston to move and thereby close a valve.
• During start up, air and condensate are expelled from the open valve.
• When the oil is sufficiently heated by the steam, the valve closes to keep the steam from escaping
• This trap contains an oil-filled cylinder encasing a sealed bellows with an enclosed piston driven rod with a valve on one end.
• When the temperature of the condensate, flowing through the trap housing, begins to rise the oil in the cylinder begins to expand in
response.
• As the oil expands it drives the rod assembly toward a valve seat located in the inlet of the trap body.
• As the condensate surrounding the cylinder cools down the oil contracts allowing the rod assembly to retract from the valve seat.
• Condensate begins to flow until it heats sufficiently to close the valve again.
• The Liquid Expansion Trap also has an adjustable nut on one end. This allows the set temperature to be adjusted within the operating
range of the trap.
Piping Department
64. Advantage
s
• Liquid expansion traps can be adjusted to discharge at low temperatures, giving an excellent 'cold
drain' facility.
• Like the balanced pressure trap, the liquid expansion trap is fully open when cold, giving good air
discharge and maximum condensate capacity on 'start-up' loads.
• The liquid expansion trap can be used as a start-up drain trap on low pressure superheated steam
mains where a long cooling leg is guaranteed to flood with cooler condensate. It is able to
withstand vibration and waterhammer conditions.
Piping Department
65. Disadvantage
s
• The flexible tubing of the element can be destroyed by corrosive condensate or superheat.
• Since the liquid expansion trap discharges condensate at a temperature of 100°C or below, it
should never be used on applications which demand immediate removal of condensate from the
steam space.
• If the trap is to be subjected to freezing conditions the trap and its associated pipework must be
well insulated.
• The liquid expansion trap is not normally a trapping solution on its own, as it usually requires
another steam trap to operate in parallel. However, it can often be used where start-up rate is not
an important consideration, such as when draining small tank heating coils.
Piping Department
66. Thermostatic Steam
Traps
Balanced pressure type
Operation of balanced
pressure steam trap
capsule
• The trap will open whenever it is in contact with
anything that is cooler than condensate at the
pressure at which the plant is working.
• It will therefore pass air whenever the air has
cooled to below steam temperature.
• Balanced pressure traps are very light, small and
cheap.
• They are not suitable for handling large quantities.
• The expansion element consists of one or more
capsules or bellows.
• This element expands and contracts in response
to temperature changes.
Piping Department
67. Advantage
s
• The flexible tubing of the element can be destroyed by corrosive condensate or superheat.
• Small, light and has a large capacity for its Size.
• The valve is fully open on start-up, allowing air and other non-condensable gases to be discharged
freely and giving maximum condensate removal when the load is greatest.
• This type of trap is unlikely to freeze when working in an exposed position (unless there is a rise in
the condensate pipe after the trap, which would allow water to run back and flood the trap when the
steam is off).
• The modern balanced pressure trap automatically adjusts itself to variations of steam pressure up
to its maximum operating pressure. It will also tolerate up to 70°C of superheat.
• Trap maintenance is simple. The capsule and valve seat are easily removed, and replacements
can be fitted in a few minutes without removing the trap from the line.
Piping Department
68. Disadvantag
es
• The older style balanced pressure steam traps had bellows which were susceptible to damage by
waterhammer or corrosive condensate.
• Welded stainless steel capsules introduced more recently, are better able to tolerate such
conditions.
• In common with all other thermostatic traps, the balanced pressure type does not open until the
condensate temperature has dropped below steam temperature (the exact temperature difference
being determined by the fluid used to fill the element).
• This is clearly a disadvantage if the steam trap is chosen for an application in which waterlogging
of the steam space can not be tolerated, for example; mains drainage, heat exchangers, critical
tracing.
Piping Department
69. c) Thermodynamic Steam
traps
Thermodynamic traps work on the difference in dynamic response to velocity
change in flow of compressible and incompressible fluids.
As steam enters, static pressure above the disk forces the disk against the
valve seat. The static pressure over a large area overcomes the high inlet
pressure of the steam.
As the steam starts to condense, the pressure against the disk lessens and
the trap cycles. This essentially makes a TD trap a "time cycle" device: it will
open even if there is only steam present, this can cause premature wear. If
non condensable gas is trapped on top of the disc, it can cause the trap to
be locked shut.
Piping Department
70. Types of Thermodynamic Steam
Traps
• Traditional disc type
• Orifice type
Piping Department
71. Thermodynamic Steam
Traps
Traditional thermodynamic type
The trap operates by means
of the dynamic effect of flash
steam as it passes through
the trap. The only moving
part is the disc above the flat
face inside the control
chamber or cap.
On start-up, incoming
pressure raises the disc, and
cool condensate plus air is
immediately discharged from
the inner ring, under the disc,
and out through three
peripheral outlets (only 2
shown, Figure i).
At the same time, the flash steam pressure builds up
inside the chamber above the disc, forcing it down against
the incoming condensate until it seats on the inner and
outer rings. At this point, the flash steam is trapped in the
upper chamber, and the pressure above the disc equals
the pressure being applied to the underside of the disc
from the inner ring. However, the top of the disc is subject
to a greater force than the underside, as it has a greater
surface area.
Hot condensate
flowing through the
inlet passage into the
chamber under the
disc drops in
pressure and
releases flash steam
moving at high
velocity. This high
velocity creates a
low pressure area
under the disc,
drawing it towards its
seat (Figure 11.4.1,
ii).
Eventually the trapped pressure in the
upper chamber falls as the flash steam
condenses. The disc is raised by the now
higher condensate pressure and the
cycle repeats (Figure 11.4.1, iv).
Piping Department
72. Advantages
• Thermodynamic traps can operate across their entire working range without any adjustment or
change of internals.
• They are compact, simple, lightweight and have a large condensate capacity for their size.
• Thermodynamic traps can be used on high pressure and superheated steam and are not affected
by waterhammer or vibration.
• As the disc is the only moving part, maintenance can easily be carried out without removing the
trap from the line.
Piping Department
73. Piping Department
Disadvantages
Thermodynamic steam traps will not work positively on very low differential
pressures, as the velocity of flow across the underside of the disc is
insufficient for lower pressure to occur.
74. Thermodynamic Steam
Traps
Orifice Type
The basic principle behind this trap is that the expanded volume of
steam
compared to condensate has a throttling effect at the orifice.
These are devices containing a hole of predetermined diameter to
allow a
calculated amount of condensate to flow under specific pressure
conditions. In
practice, condensate loads and steam pressures can vary
considerably. For
instance, start-up and running loads can differ considerably along
with steam
pressure which will change due to the actions of temperature controls.
These
varying conditions can result in the fixed orifice either holding back
condensate
in the process or passing live steam, which can affect plant
performance and
Piping Department
75. Fixed orifices are often sized on running conditions, so that they hold
back
enough condensate and do not pass steam. If this is so, at start-up,
they are
undersized to a greater degree and the steam space stands a good
chance
of waterlogging.
The alternative is to size them so as not to waterlog during start-up.
The hole is then effectively oversized for running conditions, and the
device will pass steam. The size of hole is usually a compromise
between the two conditions, such that, at some points in between,
the hole is correctly sized.
Piping Department
Thermodynamic Steam Traps
Orifice Type
77. Disadvantages
Advantages
• Can be used successfully when pressures and loads are constant.
• There are no moving parts.
• Can be used successfully when pressures and loads are constant.
• If sized on running load, fixed orifice traps will waterlog on start-up, reducing
plant performance over this period, increasing start-up times and the risk of
corrosion.
• If sized on start-up load, fixed orifice traps will waste steam when the plant
is running, effectively increasing running costs.
• Fixed orifice traps often block with dirt due to the small size of orifice.
• The cost of replacing a heat exchanger due to corrosion will be far higher
than the cost of replacing the fixed orifice trap with a steam trap.
Note: Fixed orifice traps are not recommended for draining condensate
from any application susceptible to varying load conditions.
Piping Department
78. Applicable Codes and Standard
• Pressure ratings per ANSI/FCI-69-1
• Performance testing per ANSI/ASME PTC-39.1
• End connections per ANSI B1.20 for threaded ends, per ANSI
B16.11 for socket welding ends.
Piping Department
81. Rupture Disc
A rupture disc or bursting disc is a pressure relief device that protects
a
vessel or system from over pressurization.
Piping Department
83. Features
• Rupture discs have a one-time-use membrane that fails at a
predetermined pressure, either positive or vacuum.
• Rupture discs provide fast response to an increase in system
pressure but once the membrane has failed it will not reseal.
• A rupture disk is just another pressure relieving device. It is used
for the same purpose as a relief valve, to protect a vessel or
system from overpressure that can cause catastrophic failure and
even a death.
Piping Department
84. When to use?
• Rupture disks cost less than
relief valves. They generally
require little to no
maintenance.
• A rupture disk is a non
reclosing device, which means
once it opens, it doesn’t close.
• Rupture disks are extremely
fast acting.
Piping Department
85. • System contents can plug the
relief valve during relief.
• High viscosity liquids.
Piping Department
86. Used as alone and with relief
valve
A stand-alone rupture disk is used when:
• You are looking for capital and maintenance savings
• You can afford to loose the system contents
• The system contents are relatively benign
• You need a pressure relief device that is fast acting
• A relief valve is not suitable due to the nature of the system
contents
A rupture disk / relief valve combination is used when:
• You need to ensure a positive seal of the system
• The system contains solids that may plug the relief valve over
time
• TO SAVE MONEY! If the system is a corrosive environment, the
rupture disk is specified with the more exotic and corrosion
resistant material
Piping Department
87. Construction
Material
• Standard materials of construction are carbon steel and 316
Stainless Steel.
• Commonly used: Inconel, Monel, Aluminium, Nickel, Hastelloy B
& C
• Less Commonly used: Gold, Titanium, Platinum, Silver
Piping Department
89. Strainers
To protect the mechanical equipments such as pumps, condensers,
compressors, heat exchangers etc. from the detrimental effect of
sediment,
rust, pipe scale or other extraneous debris
Piping Department
Purpose
90. Types of
Strainers
Mainly of 2 types according to their body configuration-
• Y-type
• Basket type
Piping Department
91. Y-Type Strainer
1. Body
2. Cover
3. Basket
4. Gasket
5. Plug
6. Gasket Plug
7. Bolts / Nuts
• Its body has a compact cylindrical shape that is very strong and
can handle high pressures
• Lower dirt holding capacity
• Used where infrequent cleaning is required (difficult to clean)
• Preferred for steam and other gases, also used in liquids
• Can be installed horizontally as well as vertically
Piping Department
93. Basket Type
• Pressure drop is less due to larger
free straining area
• Preferred for liquids
• Basket type strainer the preferred
type for liquid applications.
• Greater dirt holding capacity
• Can only be installed only in
horizontal pipelines
Piping Department
94. Criteria for
selection
• Flow rate
• Dirt holding Capacity
• Size of perforation
• Installation Orientation
Piping Department
95. Types of screens
• Perforated screens – Formed by punching a large number of
holes in a flat sheet of the required material using a multiple
punch. The perforated sheet is then rolled into a tube and spot
welded relatively coarse screens and hole sizes typically range
from 0.8 mm to 3.2 mm. Consequently, perforated screens are
only suitable for removing general pipe debris.
• Mesh screens - Fine wire is formed into a grid or mesh
arrangement. This is then commonly layered over a perforated
screen, which acts as a support cage for the mesh.
By using a mesh screen, it is possible to produce much smaller
hole sizes than with perforated screens. Hole sizes as small as
0.07 mm are achievable. Subsequently, they are used to remove
smaller particles which would otherwise pass through a perforated
screen.
Piping Department
96. End
connections
• Threaded
-Usually a tapered female pipe thread.
• Flanged
• Weld ends
- Socket weld are available upto 3’’
• Special ends
Piping Department
97. Material of
Construction
• Carbon steel
Body - ASTM A216 Gr. WCB
Screen - 304 Stainless Steel, ASTM A240
Gasket - Spiral wound graphite filled
Cap - Forged steel A105N
Carbon steel ASTM A216 WCB
Bolts - Carbon steel ASTM A193 B7
End connections- SCREWED NPT / SOCKET WELD or as per
customers specification.
Flanged to ANSI B16.5 or as per customers
specification
• Stainless Steel
Body - ASTM A351 CF8M
Cap - ASTM A479 316L
Strainer screen -ASTM A240 316L
End connections- SCREWED NPT / SOCKET WELD or as per
customers specification.
Flanged to ANSI B16.5 or as per customers
specification
Piping Department
98. Datasheet
• Type of Strainer (Simplex, Duplex, Self-
Cleaning)_____________________
• Material of Construction (C.I., C.S., S.S.)
___________________________
• Basket Perforation Size _________________________________________
• Mesh Liner Desired, if so Mesh Size _______________________________
• Open Area % Desired (if known) __________________________________
• Maximum System Pressure Desired(PSI)___________________________
• Maximum Operating Pressure (PSI) _______________________________
• Maximum Pressure Drop Desired (If known)
_________________________
• Flow in GPM _________________________________________________
• Product to be Strained (Oil, Water, etc.)
____________________________
• Viscosity (If other than water) ____________________________________
• Specific Gravity (If other than water)
_______________________________
• Pipe Size Desired in Inches ______________________________________
• Other Information you want us to
• Consider In Sizing/Recommendation ______________________________
Piping Department
100. Flame
Arrestor
• Passive devices
• Allows gas to pass through but stops a flame in order to prevent a
large fire or explosion
• Quench the flame by absorbing the heat of the flame
• Use wound crimped metal ribbon type flame cell element.
All flame and detonation arrestors work on the same "heat
absorption" theory:
• Disperse the flame front
• Release its energy
• Cool flame to below ignition point of the gas/vapour contained in
the system
Flame stabilised on
arrestor element
Flame arrestor
element absorbs
and quenches
flame front
Protected side
Exposed side
Piping Department
101. Contd.
• The thin metal ribbons, or elements, draw the heat out of the gas
and conducts it to the surrounding environment. The triangular
channels divide the gas, exposing as much surface area as possible.
The triangular channels also help to break up the pressure wave,
thereby reducing the impact on equipment.
• Elements consists of alternate layers of crimped and uncrimped
metal built into a circular frame
• To quench a flame the height of the cells in the element are below
the MESG of the gas/ vapour therefore stopping onward passage.
• The type of gas in the system and it’s corresponding gas group
determines the design of the arrestor element. The SS316L element
must be designed to accommodate the specific gas group that could
possibly ignite and propagate in the system. The available designs
consist of
International Electric Code (IEC) group gases
into IIC, IIB, IIA and I, the National Electric Code
(NEC) groups gases into A, B, C and D categories
depending on the MESG value of the gas.
Piping Department
102. Factors affecting flame propagation
• Pipe lengths, bends or flow obstructions.
• Initial operating pressure
• Flame stabilization on the element.
• MESG value of a gas
Piping Department
103. Types
• End-of-line (vent to atmosphere)
- for unconfined low pressure deflagrations
- installed in furnace air inlets and exhaust stacks.
• In-line
- deflagration
- detonation
• Designed, manufactured and tested according to API2000 and
BS7244
Piping Department
104. Selection
criteria
• For end-of-line flame arrestor
- hazardous group designation
- Process gas temperature
- material of construction
- Connection type and size
- Flame stabilization performance characteristics
• For in-line flame arrestor
- Location of the ignition source from the arrestor
- What needs to be protected
- Initial operating pressure
Piping Department
105. Material of
construction
• Housing construction - Aluminium, Cast Iron, Cast Steel, 304ss and
316Lss.
Flame cell element - 316Lss in a crimped ribbon form
Piping Department
Standard Design Special Design
Body C.I Welded C.S S.S &AL
Element Ring S.S S.S S.S
Element 316L S.S
Standard Coating Inside and outside epoxy 250 micron without S.S & Al Part.
106. Installatio
n
• To be mounted either vertically or at angle to allow for fluid drain.
• To avoid blockage or increased pressure drop due to plugging off
of the cell
Piping Department
