1 steam training terumo
TRANSCRIPT
ST-01-00
INTERNAL TRAININGFOR
STEAM PIPING WORK
TAIKISHA VIETNAM ENGINEERINGTERUMO BCT PROJECT
VERSION 1OCTOBER 2013
PURPOSEGive critical knowledge to staffs
A Saturated Steam Property
A 1. Absolute Pressure and Gauge PressureA 2. Saturated Steam Property
B Steam pipe expansionB 1. Expansion amountB 2. Long Pipe/Main Pipe Expansion absorbtion (Expansion Joint, Expansion Loop, Fixing and Guiding)
* Expansion Joint* Expansion Loop* Fixing* Guiding
B 3. Branch ( 2 elbow, 3 elbow ..), it depends on lengh from fixed pointB 4. Steam Piping arround Equipment
C Steam condensateC 1. Steam condensateC 2. Steam trap selection, location; Steam drain pipe inside of hot well tank; Reducer, valve directionC 3. Insulation of Steam trapC 4. Flash SteamC 5. Flash tank
D Pressure reducing valveSteam Pressure reducing valve
E Steam Pressure GaugeSteam Pressure Gauge
ST-01-01TERUMO BCTSTEAM PIPING
TRAINING CONTENTS
ST-01-02A-1STEAM PIPING
ABSOLUTE PRESSURE and GAUGE PRESSURE
Absolute pressure and gauge pressureGauge pressure. ..Gauge pressure is the pressure as indicated by a gauge. It is important to understand that gauges are calibrated to read zero at atmospheric pressure. Gauges measure only the difference in pressure between the total pressure of the fluid in the vessel and the atmospheric pressure.
Gauge pressures are expressed as "kgf/cm2G", "psig" or"kPa(G)".
Absolute pressure.. .Absolute pressure is the "total" or "true" pressure of a fluid. When the fluid pressure is greater than the atmospheric pressure, the absolute pressure of the fluid is determined by adding the atmospheric pressure to the gauge pressure, and when the fluid pressure is less than the atmospheric pressure, the absolute pressure of the fluid is found by subtracting the gauge pressure from the atmospheric pressure.Absolute pressures are expressed as "kgf/cm2abs", "psia" or "KPa (A)"However, it is normal to omit "G", "g", "abs" or "a" except when it is necessary to discriminate gauge pressure from absolute
Example 1: A pressure gauge reads 1.8MPa (18kgf/cm2). What is the absolute pressure in this case?Solution : Absolute pressure=[1.8+0.1] MPa; (18+1.03) kgf/cm2 =1.9MPa; (19.03kgf/cm2)
Example 2 : A compound gauge on the suction pipe reads 200mmHg. What is the absolute pressure?Solution : Absolute pressure=760-200=560mmHg
(bar) (°C) (m3/kg) (kg/m3) (kJ/kg) (kcal/kg) (kJ/kg) (kcal/kg) (kJ/kg) (kcal/kg) (kJ/kg)
1 99.63 1.694 0.59 417.51 99.72 2675.4 639.02 2257.9 539.3 2.02671.1 102.32 1.549 0.645 428.84 102.43 2679.6 640.01 2250.8 537.59 2.03731.2 104.81 1.428 0.7 439.36 104.94 2683.4 640.93 2244.1 535.99 2.04761.3 107.13 1.325 0.755 449.19 107.29 2687 641.77 2237.8 534.49 2.05761.4 109.32 1.236 0.809 458.42 109.49 2690.3 642.56 2231.9 533.07 2.06731.5 111.37 1.159 0.863 467.13 111.57 2693.4 643.3 2226.2 531.73 2.07681.5 111.37 1.159 0.863 467.13 111.57 2693.4 643.3 2226.2 531.73 2.07681.6 113.32 1.091 0.916 475.38 113.54 2696.3 643.99 2220.9 530.45 2.0861.7 115.17 1.031 0.97 483.22 115.42 2699 644.64 2215.8 529.22 2.0951.8 116.93 0.977 1.023 490.7 117.2 2701.5 645.25 2210.8 528.05 2.10371.9 118.62 0.929 1.076 497.85 118.91 2704 645.83 2206.1 526.92 2.11242 120.23 0.885 1.129 504.71 120.55 2706.3 646.39 2201.6 525.84 2.1208
2.2 123.27 0.81 1.235 517.63 123.63 2710.6 647.42 2193 523.78 2.13722.4 126.09 0.746 1.34 529.64 126.5 2714.6 648.36 2184.9 521.86 2.15312.6 128.73 0.693 1.444 540.88 129.19 2718.2 649.22 2177.3 520.04 2.16852.8 131.2 0.646 1.548 551.45 131.71 2721.5 650.03 2170.1 518.32 2.18353 133.54 0.606 1.651 561.44 134.1 2724.7 650.77 2163.2 516.68 2.1981
3.5 138.87 0.524 1.908 584.28 139.55 2731.6 652.44 2147.4 512.89 2.23314 143.63 0.462 2.163 604.68 144.43 2737.6 653.87 2133 509.45 2.2664
4.5 147.92 0.414 2.417 623.17 148.84 2742.9 655.13 2119.7 506.29 2.29835 151.85 0.375 2.669 640.12 152.89 2747.5 656.24 2107.4 503.35 2.3289
5.5 155.47 0.342 2.92 655.81 156.64 2751.7 657.23 2095.9 500.6 2.35856 158.84 0.315 3.17 670.43 160.13 2755.5 658.13 2085 498 2.3873
6.5 161.99 0.292 3.419 684.14 163.4 2758.9 658.94 2074.7 495.54 2.41527 164.96 0.273 3.667 697.07 166.49 2762 659.69 2064.9 493.2 2.4424
7.5 167.76 0.255 3.915 709.3 169.41 2764.8 660.37 2055.5 490.96 2.4698 170.42 0.24 4.162 720.94 172.19 2767.5 661 2046.5 488.8 2.4951
8.5 172.94 0.227 4.409 732.03 174.84 2769.9 661.58 2037.9 486.73 2.52069 175.36 0.215 4.655 742.64 177.38 2772.1 662.11 2029.5 484.74 2.5456
9.5 177.67 0.204 4.901 752.82 179.81 2774.2 662.61 2021.4 482.8 2.570210 179.88 0.194 5.147 762.6 182.14 2776.2 663.07 2013.6 480.93 2.594411 184.06 0.177 5.638 781.11 186.57 2779.7 663.91 1998.6 477.35 2.641812 187.96 0.163 6.127 798.42 190.7 2782.7 664.64 1984.3 473.94 2.687813 191.6 0.151 6.617 814.68 194.58 2785.4 665.29 1970.7 470.7 2.732714 195.04 0.141 7.106 830.05 198.26 2787.8 665.85 1957.7 467.6 2.776715 198.28 0.132 7.596 844.64 201.74 2789.9 666.35 1945.2 464.61 2.819716 201.37 0.124 8.085 858.54 205.06 2791.7 666.79 1933.2 461.74 2.86217 204.3 0.117 8.575 871.82 208.23 2793.4 667.18 1921.6 458.95 2.903618 207.11 0.11 9.065 884.55 211.27 2794.8 667.53 1910.3 456.26 2.944519 209.79 0.105 9.556 896.78 214.19 2796.1 667.83 1899.3 453.64 2.984920 212.37 0.1 10.047 908.56 217.01 2797.2 668.1 1888.7 451.1 3.024821 214.85 0.095 10.539 919.93 219.72 2798.2 668.33 1878.3 448.61 3.064322 217.24 0.091 11.032 930.92 222.35 2799 668.54 1868.1 446.19 3.103423 219.55 0.087 11.525 941.57 224.89 2799.8 668.71 1858.2 443.82 3.142124 221.78 0.083 12.02 951.9 227.36 2800.4 668.86 1848.5 441.5 3.180525 223.94 0.08 12.515 961.93 229.75 2800.9 668.99 1839 439.23 3.218726 226.03 0.077 13.012 971.69 232.08 2801.4 669.09 1829.7 437.01 3.256727 228.06 0.074 13.509 981.19 234.35 2801.7 669.17 1820.5 434.82 3.294428 230.04 0.071 14.008 990.46 236.57 2802 669.24 1811.5 432.67 3.33229 231.96 0.069 14.508 999.5 238.73 2802.2 669.28 1802.7 430.56 3.369530 233.84 0.067 15.009 1008.33 240.84 2802.3 669.31 1793.9 428.48 3.4069
(total heat)
The Saturated Steam Table with properties as boiling point, specific volume, density, specific enthalpy, specific heat and latent heat of vaporization
ST-01-03A-2STEAM PIPING
SATURATED STEAM PROPERTY
Abs. pres.Boiling point
Specific volume (steam)
Density (steam)
Specific enthalpy
of liquid water (sensible heat)
Specific enthalpy of steam Latent heat of
vaporizationSpecific
heat
Example: A pressure gauge at Steam header indicates 7.0kgf/cm2. What is the steam temperature in this case?Solution : Absolute pressure= (7.0+1.03) kgf/cm2 = 8.03kgf/cm2 => Steam temperature is ~ 170 °C
Linear coefficient of expansion of various material pipes α ; Unit m/m℃
(source) Mechanical engineering handbookFor PVC pipe, reference value of manufacturer
Carbon Steel Pipe
SUS Pipe
Copper Pipe
Polyvinyl chloride pipe (60~80)×10-6
Copper pipe 16.5×10-6
Stainless pipe 16.7×10-6
Steel pipe 12.2×10-6
Cast iron pipe 10.5×10-6
184
0.20.40.60.81
134152165175
Saturatedvapor temp℃
120
Pipe expansion/contraction per meter
Gauge pressureMPa0.1
Saturated vapor temperature
96-2ST-01-04
H-103-EB-1
STEAM PIPINGEXPANSION AMOUNT
Steel pipe
Stainless steel , copperPVC
Pipe
exp
ansi
on/c
ontra
ctio
n pe
r met
er (m
m)
Temperature difference ⊿t(℃)
The temperature expansion of pipes depends on the start and final temperature of the pipe and the expansion coefficient of the piping material at the actual temperature. The general expansion formula can be expressed as:
ΔL = α x L x Δt
whereΔL = expansion (m, inch)L = length of pipe (m, inch)Δt = temperature difference (˚C, ˚F)α = Linear coefficient of expansion (m/m˚C)
)()()/(3)( 102.12 Ct
mCmmmEX
mm Oo
LL Δ×××=Δ −
)()()/(3)( 107.16 Ct
mCmmmEX
mm Oo
LL Δ×××=Δ −
)()()/(3)( 105.16 Ct
mCmmmEX
mm Oo
LL Δ×××=Δ −
TWO METHODS (for TERUMO BCT SITE)
METHOD 1: EXPANSION LOOP
Advantages:1. Water leak: very low posiblity [Note] 1. All the fittings of expansion loop should be welded2. Anchor load: small 2. Should be mounted in between fixed points3. Installation cost: inexpensive 3. Should not be branched from the loop4. Access hole: not necessary5. Installation place: roof space, horizontal * Although many designers frequently use EJ,
expansion loop is more effective for hot/cold water piping which allows smaller expansion capacity.
Disadvantages1. Need big space for loop installation
METHOD 2: EXPANSION JOINT
Advantages [Note] 1. Guiding bolt must be removed1. Need small space after installation
2. Mainly accommodate axialDisdvantages: movement while slightly absorb1. Water leak: High Posiblity lateral movement2. Anchor load: Big 3. Should be mounted in the3. Installation cost: Expensive right direction4. Access hole: Necessary (must) 4. Pipes should be guided to5. Installation place: Piping rack accommodate vibration6. Expansion capacity: max. 50 mm 5. Should not be over-pressurized7. Guiding: needs multiple guides in water pressure test on site
(standard interval of steel bracing is acceptable)
ST-01-05B-2STEAM PIPING
PIPE EXPANSION ABSOBTION
Guide Anchor/Fixing
Guide Anchor/Fixing
Loop
Expansion
METHOD 1: EXPANSION LOOP
Installation of expansion loop(1) Expansion loop size --- carbon steel piping
Example Pipe diameter 4" with expansion capacity 100mmW and H of loop should be: W=1.5m and H=3.3m
Test Pipe diameter 50A with expansion capacity 48mm
W and H of loop should be: W=……………...m and H=…………………..m
ST-01-06B-2STEAM PIPING
PIPE EXPANSION ABSOBTION
Expansion capacity e (mm)
Pip
e di
amet
er (B
)
METHOD 2: EXPANSION JOINT
EXAMPLE OF VENN JB-14 SERIES
NOTE:Pipe Expansion <=> Expansion Joint Contraction
ST-01-07B-2STEAM PIPING
PIPE EXPANSION ABSOBTION
ExpansionExpansion
ContractionContraction
FIXING AND GUIDING METHODA. Fixing/guiding interval
(material: SS400)(1kg=9.8N, 1kg/cm2=0.098MPa)
Relation of normal pressure (P kg/cm2) andguiding interval L2 (carbon steel pipe)
Requirements for 1. able to withstand horizontal loadmetallic attachment 2. avoid unnecessary material
3. easy to manufacture (simple structure)
h should be as small as possible(to reduce bending moment)
102H-104-AB-2
STEAM PIPINGPIPE EXPANSION ABSOBTION
Nominal size
3/8
Allowable shear stress
ST-01-08
Allowable stress 58.8MPa (600kg/cm2)
26 (265)
under normal state kN(kg)
(1176)(1633)
1/25/83/47/8
115160
4677
(2145)(2698)
1 1/4 1 3/8
1 1 1/8
210264339402493558
(6789)(7691)
(5033)(5697)
(470)(787)
2 877 (8947)
(3462)(4102)
753
1 1/2 1 5/8
Bolt shear stress
1 3/4 1 7/8
665
δ1>δ2
Cantilever shear stress
Normal pressure (kg/cm2)
Guiding interval(m)
Guided
Guided
(double-bellows)
Anchor
When pipe diameter is D, L1 should not exceed 4D
(single-bellows)Anchor Anchor
Fixed Fixed
FIXING AND GUIDING METHODB. Fixing/guiding of steam or hot water piping
1. Making use of structural beam
If piping load exceeds 1.96kN (2,000kg), gusset plateshould be installed to reinforce bracket
Bending moment on fixed point includes weight of riser.ℓ should be as short as possible.
ST-01-09103H-104-B
B-2STEAM PIPING
PIPE EXPANSION ABSOBTION
ℓ
(Material)
Expandwelded
insulation
[Main fixing point]
Angle steel (H≦800)20-100A L5x40x40125-250A L5x50x50
Anchor bolt (p<5kg/cm2)20-100A 12φ x 4 pcs125-250A 15φ x 6pcs
(+2pcs for existing building)
Insulationgusset plate
welded
[Main/sub-fixing point]
W=D+200
D --- Pipe nominal size
expand welded
Reinforcmentbeam
metallic
Channel steel
or[Riser]
l
[Riser]
FIXING AND GUIDING METHOD2. Making use of slab --- fixing onto slab is not recommended (possibility of fall)
3. Inside tunnel
Piping arrangement is designed along the wall For pipe hanger, flat bar is preferred to round bar,in order to secure space for maintenance. which should be welded to pipe.Fixing/guiding method with the help of wall For , strength of anchor bolt should be checkedshould be sought. especially for high-temperature steam service.
4. Fixing of bending part
ST-01-10104H-104-B
B-2STEAM PIPING
PIPE EXPANSION ABSOBTION
(Material)
Angle steel (H≦1,000)20-100A L5x40x40125-250A L5x50x50
Anchor bolt (p<5kg/cm2)20-100A 12φ x 4 pcs125-250A 15φ x 6pcs
W=D+200D --- Pipe nominal size
[Main/sub-fixing point]
Insulation
welded
approx 1/5 H
When H>800
weldedwelded
welded
welded
waterproofmortar
Concrete pad Anchor bolt
hooked up with slab reinforcement
welded welded
welded
C
FIXING AND GUIDING METHOD5. Inside trench
6. Guiding[Requirements of metallic guides] a. Friction should be smaller
b. Piping misalignment or movement should be restrained
(Ceiling-mounted piping)
(Riser) (Floor-mounted piping)
* Although pipe itself can be entirely insulated,installation of pipe shoes is somewhat painstaking.
ST-01-11105H-104-B
B-2STEAM PIPING
PIPE EXPANSION ABSOBTION
Plan view
PlateSleeve
Elevation viewRiser clamp
Insulation tube
Pipe hangers and supports
Regular roller support Hanger Pipe sleeve U-bolt or flat bar pipe strap
Chain Chain Bracket
Guide Hanger Hanger Guide Fixed
* Guides should be installed every 2-3 hangers
weldedwaterproof(asphalt, pitch, etc.)
U-bolt to eliminate vibrationroller support
* prepare drain ditch where necessary
FIXING AND GUIDING METHODC. Fixing/guiding of hot/cold water piping
1. Insulated pipinga) insulation may interfere with fixing/guidingb) condensation may occur through bolt
Although condensation canbe completely prevented, this requires higher cost.
2. Fastening by welding on site
[Note] Pipe can be tightly attached in the above method, but condensation mayoccur with cold water piping. Applicable only for hot water piping.
3. Pipe is insulated at sub-fixing point (where tight fastening is not necessary)
For cooling water piping1. Expansion loop is preferred if space is available2. Wood or rigid urethane O-ring should be applied at hanging part of pipe
ST-01-12106H-104-C
B-2STEAM PIPING
PIPE EXPANSION ABSOBTION
Insulation
welded direction of
Insulation (cypress)*lauan not acceptable
U-bolt welded to pipe
Rigid urethane O-ring
welded
insulation
welded
welded
W=D+200(D --- pipe nominal size)
Rigid urethane O-ring
Insulation (rigid urethane O-ring)
Insulation (cypress)
Guiding bracket
U-bolt or hanger (* if fixed, bending moment works on bracket) Dew drain pan
(if necessary; EJ should not be installed in the room which is susceptible to water leak)
A. Branch piping of horizontal main pipe
B. Use of eccentric reducer
C. Avoiding obstruction
D. Use of globe valve
Globe valve should not be installed in horizontal pipewhich carries large volume of steam condensate. Condensate is likely to be trapped in the valve.(Valve may be installed horizontally where volume of condensate is fewer (e.g.) bypass of pipe end trap)
Steam pipe dia. Drainpipe dia. Return pipe dia. Equalizer dia.
125~150 50 125~150 5080~100 40 80~100 4050~65 32 50~65 32
25~40A 20A 25~40A 20A
ST-01-1362F-102-A.B.C.D
B-4STEAM PIPING
BRANCH PIPING (EXAPMPLES)
Bad
expansion/ contraction
expansion/ contraction
branch (up)
Branch (upward) Branch (upward)Branch (downward)
Riser (down) Horizontal
main* Condensate is likely trapped
not exceed 600
* Pipe end trap of main pipe is omitted.
Steam
Steam
Steam
Steam
Steam condensate
Steam condensate
approx. 400
upward (Not against the steam flow)
downward
BushingBushing
Steam
Obstruction
Drain plugor valve (15A)
drainpipe
Steam
Drain plugor valve (15A)
Obstruction
Return
Steam condensate and dirt
Steam condensate
Steam condensate and dirt
Steam d
Equalizer
POINT
POINT
* BRANCH PIPING MOVES DUE TO MAIN PIPING THERMAL EXPANSION/CONTRACTION
Comparison by installation position
a) Single fixed point and no support at the end1. Friction of guides should be minimized and guides should withstand buckling load of pipe2. Branch pipe should also accommodate expansion/contraction of pipe
(combined with three elbows, etc.)3. Force at A-1 is small (friction of guides, etc.)
b) Single-bellows EJ with two fixed points1. Horizontal load on anchors is larger than c) below2. Branch pipe should also accommodate expansion/contraction of pipe
(combined with three elbows, etc.)3. Distance between the two fixed points should be within the allowable expansion capacity of EJ
c) Double-bellows EJ with two fixed points1. Since thermal expansion/contraction (δ) is smaller than a) and b) above, anchor load is small.
(* where it is necessary to minimize piping stress on construction such as building, etc.)2. Double-belows EJ is more expensive than other types3. Expansion capacity is larger than b) above and d) below.
d) Two fixed points and EJ (single-bellows) at the end1. Horizontal load on anchors is larger than c) above but smaller than b).2. Branch pipe should also accommodate expansion/contraction of pipe
(combined with three elbows, etc.)3. EJ is less expensive than b) above, but its expansion capacity may become smaller -should be checked in advance.
ST-01-1495H-103-B
B-4STEAM PIPING
BRANCH PIPING (EXAPMPLES)
expansion/contraction
shrink/stretch Not fixed
(single-
expansion/contraction expansion/contraction(double-bellows)
(single- bellows)
expansion/contraction
expansion/contraction expansion/contraction
expansion/contraction
expansion/contraction
expansion/contractio
expansion/contractio
E. Steam branch piping [Reference](the number of elbows combined with)
Low pressure steam Lower than 1.0MPaCondition Temperature difference 100℃ (100℃-0℃=100℃)
Pipe length 25mAverage expansion coefficient of steel pipe 12x10-6mm/mm ℃
ST-01-1563F-102-E・F
B-4STEAM PIPING
BRANCH PIPING (EXAPMPLES)
4 elbows
2 elbows 3 elbows
2 elbows 3 elbows 4 elbows
expansion/ contraction
expansion/ contraction
expansion/ contraction
Dis
tanc
e fr
om
anch
or to
elb
ow
Distance from anchor to the point of branching out
Anchor Horizontal steam main Expansion joint Anchor
mm
ST-01-16B-4STEAM PIPING
BRANCH PIPING - REMINDER
A. Around boiler
◎
(3) Water-tube boilera. Steam drum is protected from boiling water
and branch pipe does not have to rise.b. Branch pipe should be combined with 4 or
more elbows to prevent thermal expansionin one direction
(4) Smoke tube boiler-1 (5) Smoke tube boiler-2Branch pipe should be combined with [for machine room with limited space]4 or more elbows. In case space is not available to install branch pipeHorizontal pipe should run over 2m each. combined with 4 or more elbows, ball joint shouldLong elbow for welding should be used. be used to absorb thermal expansion.
ST-01-1757F-101-A
B-3STEAM PIPING
STEAM PIPING ARROUND EQUIPMENT
Steam drum
Water drum
Over 2m Over 2m
Ball joint
Over 2m
According to the law, building a branch pipe from the boiler to the 1st valve is designated as boiler engineering work, which requires the license of boilder welder. (the license is not required for screwed-type
Example :From Boiler to Header: 5 Elbows
POINT
B. Around steam (supply) headera. Size of spare valve --- steam flow (kg/h) of spare valve should
be predefined by multiplying normal steam flow (kg/h) by 0.2.* or follow specification, if provided
b. Dirt Pocket --- 80A-100Ashould be located farthest from supply main
c. Drain valveDischarge water of each circuit at start-up(to prevent steam hammer of branch pipe)Should be mounted on large-sized branch pipe (125A-)Drainpipe should be connected slightly above the spare valve.
d. Pressure gauge of each circuit --- * if necessary Socket should be prepared in advance.Supply of steam in circuit can be checked with gauge.For year-round type header (hotel, hospital, etc.), pressure gauge should be mounted on each circuit.
C. Around heat exchanger D. Ventilation of safety valve of high pressure boiler
E. Around hot well tankVent pipe --- approx. 32A-50A
(1) If installed in limited space, ventilation should be adequately done.
(2) To avoid condensation from dripping out of open endof vent pipe, pipe should be extended by 5m or longer.Or a condensate drain pipe should be built at open end,connected to water drainpipe.
Pump boost pressure should be 1m or higher.(by using tall tank, etc.)Pump suction pressure should be checked beforehand.
--- J-101 Calculation of pump suction pressure
ST-01-1858F-101- B・C・D・E
B-3STEAM PIPING
STEAM PIPING ARROUND EQUIPMENT
drain water
Plug
Spare valve
Drain valve
Trap
Dirt pocket
Air vent
Safety valve
Air vent
Relief pipe should extend to safe area outside
steam
Relief valve 25A
Drain valveTrap
Vent
Drain valve
Drain valve(open)
Gas flue
Rise up tosafe area
High-pressure boiler
Condensate returnVent pipe
Flash steam● Return pipe should NOT end here (air will enter return pipe and cause pipe to corrode)
(Atmospheric pressure) water supply
Boiler water feed pump
Silencer(if necessary)
* It is acceptable that backflow will occur due to a vacuum inside return pipe when turning off the boiler.
POINT
POINT
POINT
ST-01-1964F-103-A
C-1STEAM PIPING
STEAM CONDENSATE
Steam trapSteam traps are a type of automatic valvethat filters out condensate (i.e. condensed steam) and non-condensable gases such as air without letting steam escape. In industry, steam is used regularly for heating or as a driving force for mechanical power. Steam traps are used in such applications to ensure that steam is not wasted.
Vaporization and CondensationSteam is formed when water vaporizes to form a gas. In order for the vaporization process to occur, the water molecules must be given enough energy that the bonds between the molecules (hydrogen bonds, etc.) break. This energy given to convert a liquid into a gas is called 'latent heat'.
Steam-based heating processes use latent heat and transfer it to a given product. When the work is done (i.e. steam has given up its latent heat), steam condenses and becomes condensate. In other words, condensate does not have the ability to do the work that steam does. Heating efficiency will therefore suffer if condensate is not removed as rapidly as possible, whether in steam transport piping or in a heat exchanger.
Three physical states (phases)
TLV Information
Water
Saturation, super-heating and subcooling
Steam used for HVAC
Steam used for Power (ex thermal power
A. Type
* Need freeze protection of steam/condensate when equipment is turned off.
* Can be installed vertically; however, maintenance-wise, better to be installed horizontally.
(3)Thermodynamic trap --- operated on the difference in kinetic and thermal characteristics of steam and condensate
(1)Mechanical trap --- operated by changes in fluid density Installed horizontally
(2)Thermostatic trap --- operated by changes in fluid temperature (of steam and condensate)
ST-01-2064F-103-A
C-2STEAM PIPINGSTEAM TRAP
Open bucket --- single valve Inverted bucket --- single valve Ball foat
Bellows Bimetal (strip) Bimetal (disc)
Labyrinth 2-orifice (impulse) 2-orifice
Labyrinth Disc (lever) Disc
Control chamber
Disc
Adjustor
Cylinder
Vent
B. Comparison of steam traps
Same as left Same as left Same as left
Same as left Same as left Same as left
N/A
Moderate
Price Reasonable Reasonable Reasonable
Maintenance cost Low
Freezing
Temperature control N/A
Condensate outside bucket may damage trap
Simple structure, comparatively small compared with open bucket (single valve)
Small Large
Reasonable
N/A
Same as left Condensate tends to remain inside trap. Frozen condensate may damage trap.
Low Inexpensive
N/A
Same as left
Durable
Same as left Withstand approximate value to inlet pressure
Valve and pin joint are easily worn out
Same as left
Discharging capacity is larger than open bucket type
Same as inverted bucket Same as inverted bucket
Compared with free float, less durable because valve port is worn out
Installation Only horizontally
Structure, Size
Application
Valve is easily worn out resulting in leakage
Applicable for all pressure ranges but discharging capability is extremely small (max. 1-2t/h)
Durability
Simple structure but large sized
Change in condition of use
Automatically respond
Against back pressure
Withstand approximate value to inlet pressure
Yes
Capacity(operation cycle)
Small(intermittent)
Medium(intermittent)
Large(continuous)
Large(intermittent)
Air venting
N/A Vent small amount of air along with move of bucket. This does not affect operation.
Yes
Cooled condensate is intermittently discharged at start-up
Start-up
Steam loss None 2-3% of loss compared with open bucket
Yes Yes
Need to vent air remaining in trap
Remaining condensate is automatically discharged
Cooled condensate is continuously discharged at start-up
Inverted bucket Float (free)
Float (lever)
Steam entering open bucket causes it float/sink and thereby discharge port opens/closes
Steam entering inverted bucket causes it float/sink and thereby discharge port opens/closes
By sensing difference in density and condensate, floating ball (no attach-ment) floats/sinks to release condensate continuously
By sensing difference in density and condensate, floating ball (attached with lever of valve) floats/sinks to open/ close valve
Mechanism
ST-01-2165-1F-103-B
C-2STEAM PIPINGSTEAM TRAP
TypeMechanical
Open bucket (single valve)
\B. Comparison of steam traps
Same as left
None
Steam loss
Continuously vent air Same as left Same as left
Same as left
Same as left
Very compact Compact Compact
Anywhere Same as left
N/A OK OK
High
Inexpensive Reasonable Reasonable
Maintenance cost
Price
By installing vertically, freezing can be prevented
Same as leftFreezing
Temperature control
Suitable for low-pressure service (approx 1kg/cm2), mostly for heating
Pressure-wise, widely applicable next to open bucketApplication
DurabilityThermo-bellows is not durable
Highly durable because of less impact on valve port
Structure, Size
Installation Direction to which bellows expand/contractCondensate does not remain in trap. No possibility of freezing
Large(intermittent)
Change in condition of use
Need adjustment for even a slight change
Adjustment not necessary unless significantly changed
Extremely weak against back pressure
Extremely weak against back pressure but able to withstand to a certain extent by adjusting settings
Withstand higher back pressure than strip type.No adjustment needed up to 50% of inlet pressure for practical use
Against back pressure
Remaining condensate is automatically discharged
Discharge of remaining condensate at start-up is very smooth
Start-up
If trap is set to allow no steam loss, it takes longer until valve is opened
Air venting
Capacity(operation cycle)
Small(intermittent)
Large(intermittent)
TypeThermostatic
Thermo-bellows Bimetal (strip)
Bimetal (disk)
Thermo-bellows operates on temperature difference
Bimetallic strips made from metals with different expansion coefficients deflect by condensate temperature, permitting valve port to open/close.
Bimetallic discs made from metals with different expansion coefficients deflect by condensate temperature, permitting valve port to open/close.
Mechanism
ST-01-2265-2F-103-B
C-2STEAM PIPINGSTEAM TRAP
B. Comparison of steam traps
Application
Durability
Very compact
Anywhere
N/A
Low
Price Inexpensive Inexpensive
Temperature control N/A
Maintenance cost Moderate
No damage from freezing
By installing vertically, freezing can be preventedFreezing
Less durable because of continuous operation
Operation over the above-mentioned limit significantly affects durability
Structure, Size Compact
Change in condition of use
Better to be adjusted
Installation Anywhere
Withstand up to 70% of inlet pressure with the help of adjustment device
Withstand up to 50% of inlet pressureAgainst back
pressure
Despite steam loss, applicable for high-pressure systems, 100kg/cm2 or higher
Max pressure 10kg/cm2, discharge 1-2t/h for practical use
Automatically respond
Approx 5% of loss compared with open bucketSteam loss
Air ventingVent air along with trap operation
Same as left
Capacity(operation cycle)
Large(intermittent)
Theoretically large but small in practice(intermittent)
Flash steam of condensate creates pressure over piston which opens/closes valve
Disk is pushed up by condensate pressure and consequently valve is opened to discharge. When steam enters instead of condensate, internal pressure lowers to push down disk and valve is closed as a result.
Mechanism
Remaining condensate is automatically discharged
Depending on installation, remaining condensate may prevent valve from opening
Start-up
Need adjustment, otherwise considerable steam loss
ST-01-2365-3F-103-B
C-2STEAM PIPINGSTEAM TRAP
TypeThermodynamics
Impulse Disk
C. Pressure before/after trapWhere P1≒P2 P --- Initial steam pressure (MPa)
P1= P - ΔP(MPa) ΔP --- Total pressure drop of steam pipe (MPa)
P3 = P' + ΔP' + P' --- Pressure at the opening of steam return (MPa)No pressure (0) when drained to the atmosphere
ΔP' --- Friction loss of return pipe (MPa)h --- Rise of return pipe (m)
Pressure differential before/after trap affects volume of discharge
Estimation of trap inlet pressure (P2)● If pressure drop of H Ex is large Estimate trap outlet pressure (P3 - back pressure) to select trap type● If pressure exists at trap outlet (P3) and P1 - P3 is small affects draining capacity (QT)
QT ∝√P2-P3
* Normally, P1≒P2 however, P2 < 1.0-1.5MPa (10-15kg/cm2)
D. Calculation of working pressure differential of trap (Exercise)
P --- 0.35MPa (3.5kg/cm2)P4 --- 0.1MPa (1.0kg/cm2)Steam straight pipe length 60mSteam return straight pipe length 30m
[Solution]Trap inlet pressure P2 = 0.35 - *0.06 - *0.03 = 0.26MPa (2.6kg/cm2)* 0.06MPa (0.6kg/cm2) --- Pressure drop of steam pipe
Assuming pipe's equivalent length is double the straight length (60m) = 120m.Where pressure drop per unit pipe length is 0.05MPa (0.5kg/cm 2)/100m,
ΔP' = 0.05 ×
* 0.03MPa (0.3kg/cm2) --- Pressure drop of automatic valve (assumed approx. 3m)(◎ In principle, pressure drop of automatic valve should not be included in pipe's equivalent length, but be separately calculated)Trap outlet pressure P3 = 0.1 + *0.014 +
* 0.014MPa (0.14kg/cm2) --- Pressure drop of steam return pipeAssuming pipe's equivalent length is double the straight length (30m) = 60m.Where pressure drop per unit pipe length is 0.023MPa (0.23kg/cm 2)/100m,
ΔP' = 0.023 × = 0.014MPa (0.14kg/cm2)
∴ Pressure differential P2 - P3 = 0.26 - 0.144 = 0.116MPa (1.16kg/cm2)
Normally, rise of return pipe is max. 5m per pressure differential of 0.1MPa (1kg/cm 2).It is recommended to prepare a list of various traps with working pressure differential in advance. This should be helpful for test-run.
(Note) When automatic valve is shut, steam condensate will not be drained and thereforeaccumulate at the bottom of heat exchanger.
ST-01-2466F-103-C・D
C-2STEAM PIPINGSTEAM TRAP
h100
120100
3100
60100
= 0.06MPa (0.6kg/cm2)
= 0.144MPa (1.44kg/cm2)
Header
Trap Flash tank
E. Selection of steam trap(1) By mounting position
(free flow) (Return riser) * exceptional (Horizontal return)● Any type of trap is OK ● Open bucket type is not suitable ● Open bucket and Disk types
● Bimetal type is most suitable; are suitableshould be kept draining ● For bimetal type, it should be
● For disc type, operating cycle should be kept dischargingset shorter to discharge small amount of steam
● Need to intentionally create pressure differential between trap and the partwhere condensate is generated
(2) By piping conditiona. Condensate is charged from steam supply main --- (for drip trap)
Few restriction on trap mounting positionAllows continuous supply of steam over long hours(disk type may be suitable for the part where steam is intermittently supplied at low pressure)
b. Condensate is discharged from heat exchangerSee above (1) By mounting position
(3) By operating conditionFor intermittent operation over a short time,Need to check whether trap can vent air and its air venting capability
whether valve is opened or not when low-temperature condensate is accumulatedThe most suitable type should be Bimetal disc type
(4) Safety factor of trap
◎ (Condensate capacity under normal operation x (2 to 3)) < max capacity of product spec
(Reason) a. Because most traps operate intermittently, condensate capacity should be largerwhen valve is opened than when continuously operated.
b. Trap inlet pressure and back pressure on trap outlet under actual operation may varydepending on operational state.
c. Condensate capacity on start-up should be larger than normal operation.d. In addition to condensate, trap needs to vent air mixed in steam.
(Note) Trap's discharging capability should not be excessive.Safety factor varies depending on the type of trap. See manufacturers' catalog for more details.
Steam main pipe (downward slope)Steam rising pipebefore pressure reducing valveEquipment
33
Trap mounting position Safety factor32
ST-01-2567F-103-E
C-2STEAM PIPINGSTEAM TRAP
TLV Information
(5) Selecting trap by condition of use [Reference]
Inlet pressure Highly safe at any Widely applicable next Max. 10kg/cm2 Normally 2kg/cm2 1kg/cm2 or lesspressure to upward bucket Max. 4-5kg/cm2
Allowable back Inlet pressure should Inlet > outlet Inlet pressure should Inlet > outlet Weak against backpressure be larger than outlet. Need adjustment if be larger than double pressure
outlet pressure exceeds the outlet50% of inlet
Condensate capacity Commonly Large Max. 2-3 ton/h 500-600 kg/h Max. 9-11 ton/h Max 2 ton/hSteam supply pipeWidely applicable Widely applicable Low pressure and OK OK with low pressure
intermittent supply steamFree flow Widely applicable as OK OK OK OK
long as properly placed Riser NG OK OK NG OKHorizontal OK Continuous discharge OK OK OK
is recommendedContinuous OK OK OK OK Steam temperature
and pressure shouldbe constant
Intermittent Not recommended OK OK but trap may not Not recommended OKwork properly at start-up depending on pip-ing condition
F. Considerations in piping and mounting trap(1) Return pipe and trap mounting position
Condensate of main pipe should be returned with a separate return pipe to HWT. (Note) Where steam pressure is equal Condensate of heat exchanger should be gathered in a common return pipe. in supply mainThe number of traps to be mounted on horizontal main should be minimized. (condensate capacity should be checked)
(2) Trap mounting position
Ball float BellowsOpen bucket Bimetal disc Disk
ST-01-2668F-103-E・F
C-2STEAM PIPINGSTEAM TRAP
Pipi
ng c
ondi
tion
For e
quip
men
tO
pera
ting
cond
ition
A/C Radiator
Boosterheater (reheater)
A/C
Header
As close as possible
Return
Cooling leg over 1.2mCooling leg over 1.2m
Dirt pocket
Steam main
a. Normally, trap should be mounted nearby equipment(to prevent pressure drop at inlet and secure discharging capability)
b. Thermodynamic trap --- needs cooling leg (to ensure stable operation)
c. Pipe end trap
-- Intermittent → low --- should be set to 3-4.-- Continuous discharge → Back pressure on trap outlet is generally high --- Safety factor can be set to minimum.
(3) Checking of trap operation [Note] Install if necessary
Test valve --- to check the presence of Sight glass --- (example) TLV-T5N condensate in steam return allows to check trap operation with the move of ball
inside domed sight glass
(4) Protecting from back pressure (reduction of discharge capacity)
Decrease of trap capacity due to back pressure (%)(To ease static pressure of condensate in return main)
(5) Mounting position
(6) Use of strainer [Note] Applicable when strainer is mounted before automatic valve
(7) Mounting trap at higher position (8) Lifting trap
H is determined by pressure differentialof steam supply and return pipes. Max 5m per 0.1MPa (1kg/m2) of difference
50 20 12 675 38 30 25
Back pressure (%)
Inlet pressure (MPa)0.035 0.175 0.70
25 6% 3% 0%
ST-01-2769F-103-F
C-2STEAM PIPINGSTEAM TRAP
Sight glassTest valve (G.V.)
Return main
Connect from the above of return
Return main
back pressure
Discharge capacity decreases due to back pressure
Pressure increase due to re-vaporization of high temperature
d
Steam main
Condensate
steam steam
Condensate
open
open
open
Valveopen
openopen
* Useful for test-run. By opening the valve a couple of times, removing of strainer mesh for cleaning can be omitted.
* For anti-freezing purposes(Note) Strainer should not be placed upward.
Does not act as heater if condensate Steam main
Dirt drainvalve
Return
Discharged to return main if dirt is not contained in condensate
POINT
POINT
STEAM TRAP INSULATION
ST-01-28C-3STEAM PIPINGSTEAM TRAP
Steam transport piping is insulated to prevent steam losses due to radiant heat. It is also important to insulate valves and pressure reducing valves having large radiant heat surface areas that are connected to this piping. What about steam traps?Steam is supplied to the inlet of a steam trap, so the inlet piping should also be insulated to prevent radiant heat losses.But is it OK to insulate all steam traps without regard to the conditions? Actually, no-there are some circumstances in which it is not acceptable. There are many different types of traps, and whether or not it is OK to insulate the trap depends on what type it is.
1. Traps that can be insulated without adverse effects:
Float typeBecause the valve opens and closes based only on the change in water level inside the trap, insulating the trap has no adverse effects whatsoever.
Bucket typeThe buoyancy of the bucket is used to open and close the valve, but this happens in conjunction with the process of the steam condensing in the trap, so heavily insulating the trap may result in impaired operation.
2. Traps that should only have light insulation:
Disc type and thermostatic typeWith these types of trap, the trap must cool down for the valve to open (‘the cooling of the trap’ is a necessary condition for the valve opening movement). If the trap is insulated, it is difficult for the trap to cool down, and the opening of the valve is delayed. This delay in valve opening causes condensate that should have been discharged to pool, so these types of trap must not be insulated.
3. Traps that should only have light insulation:
As we can see from the breakdown of traps into these categories, only with float type traps is it acceptable to insulate the trap without regard to conditions. Care must be taken with all other types of traps, as over-insulating may lead to condensate pooling.
At the same time, care must also be taken that traps in the ‘should not be insulated’ group do not get too cold, as this results in the danger of the valve opening even in the absence of condensate, thus leading to large steam losses.
At the time of the oil crises some 30 years ago, there was talk in Japan of huge energy savings to be gained by placing an empty can over steam traps, and actually this idea provided a brilliant balance between not insulating at all and over-insulating. In fact, most modern-day disc traps come equipped with a cap that is similar to this empty can.
As we have seen, when insulating traps it is critical to do so only with an understanding of the trap’s characteristics.
ST-01-29C-4STEAM PIPINGFLASH STEAM
Flash SteamFlash steam is a name given to the steam formed from hot condensate when the pressure is reduced.
Flash steam is no different from normal steam, it is just a convenient name used to explain how the steam is formed. Normal or “live” steam is produced at a boiler, steam generator, or waste heat recovery generator – whereas flash steam occurs when high pressure / high temperature condensate is exposed to a large pressure drop such as when exiting a steam trap.
High temperature condensate contains high energy that cannot remain in liquid form at a lower pressure because there is more energy than that required to achieve Saturated water at the lower pressure. The result is that some of the excess energy causes a % of the condensate to Flash.
Condensate discharged out of the orifice of a trap partially evaporates (flash evaporation) due to the pressure difference (illustration).
ST-01-30C-4STEAM PIPINGFLASH STEAM
What causes Flash Steam?Flash steam occurs because the saturation point of water varies according to pressure. For example, the saturation point of water is 100 °C at atmospheric pressure, but is 184 °C at 1.0 MPaG.
So what happens when condensate kept under pressure at 184 °C is released to atmosphere? The condensate contains too much energy (enthalpy) to remain entirely liquid, and a portion of it evaporates, causing the temperature of the remaining condensate to drop to the saturation temperature (i.e., 100 °C if discharging to atmosphere). This phenomenon is known as flash evaporation.
In other words, when hot condensate is discharged into a lower pressure environment, its enthalpy (total energy) remains the same, but its saturation point drops (the temperature at which condensate can exist in both the liquid and gaseous state). To compensate for the excess amount of energy, part of the water molecules absorb the excess energy as latent heat and evaporate to form steam.
Additional NoteOne of the first things that come to mind when visualizing flash steam are the steam clouds that can appear outside a non-sub-cooling trap releasing to atmosphere. These steam clouds can often be misinterpreted as a live steam leak when in fact they are simply comprised of flashed condensate with fine water droplets in suspension, caused by the flashing of hot condensate being released to atmosphere.
ST-01-31C-4STEAM PIPINGFLASH STEAM
Calculating the % Flash Steam GeneratedThe % of flash steam generated (flash steam ratio) can be calculated from:
where:
•hf1 = Specific Enthalpy of Saturated Water at Inlet*•hf2 = Specific Enthalpy of Saturated Water at Outlet•hfg2 = Latent Heat of Saturated Steam at Outlet* In traps designed to have a significant amount of sub-cooling of the condensate before discharge, the sensible heat of condensate at the trap inlet can be significantly lower than when estimated using inlet pressure saturated steam values.
As seen in the below examples, a higher % of flash steam is generated when condensate is discharged to atmosphere (example 1) compared to when it is
2
21(%)fg
ff
hhh
Flash−
=
ST-01-32C-4STEAM PIPINGFLASH STEAM
hf1; hf2 hfg2
ST-01-33C-4STEAM PIPINGFLASH STEAM
Volume of Flash Steam generatedSteam is much less dense than water, which means that a small increase in the percentage of flash steam generated can appear as a large increase in volume of steam generated. The animation below shows the difference in ratio of steam to condensate for examples 1 and 2 (see above) when applied to condensate ret rn piping
To understand with great detail, the specific volume of condensate at 100 °C is 0.00104 m3/kg, and the specific volume of atmospheric steam is 1.67 m3/kg. When high temperature condensate at 1.0 MPaG is discharged to lower pressure such as atmosphere, 16.1% by mass of that condensate flashes into steam. The resulting volumetric ratio can be contrasted as follows:
Calculating Flash to Condensate Ratio (Metric)1.Condensate Volume: (1 - 16.1%) x 0.00104 m3/kg = 0.000873 m3/kg2.Steam Volume: 16.1% x 1.67 m3/kg = 0.269 m3/kg3.Flash to Condensate Ratio: 0.269 m3/kg / 0.000873 m3/kg = 308:1
The greater the pressure difference, the larger the amount of flash steam generated at discharge.
ST-01-34C-4STEAM PIPINGFLASH STEAM
What to Do With Flash Steam?The vapor cloud formed by flash steam is a natural by-product of condensate discharge. Since flash steam is of the same quality as live steam, modern facilities often try to reuse significant amounts of flash steam whenever possible.
Reusing flash steam generated by a higher pressure system for use in a lower pressure system can enable considerable energy savings in addition to improving a plant's working environment by reducing vapor clouds. When trying to implement a waste heat management system, condensate recovery
t d fl h t t ft l t d t th
Flash steam from a high pressure system is recovered into a flash tank and reused as steam in a low pressure system.
A. Example of use (Functions of flash tank)1. If higher- and lower-pressure return pipes are
directly connected, condensate in higher-pressurereturn will be re-vaporized and increase backpressure on lower-pressure return.Flash tank is installed to prevent this.(to reduce influence on trap capacity of lower-pressure return)
2. To make efficient use of lower pressure steamwhen higher-pressure return has large volume ofcondensate.
B. Dimension criteria
Flash tank dimensions MAX. 0.55MPa (5.5kg/cm2)
50×11/1650×9/16
50×11/1680A 80A 16 50×9/16
50A 50A 16
6000 0.43~0.55 0~0.1 1830 220 350
80A
490 150 80A
150 300 370 1253600 0.43~0.55 0~0.1 1830
32×3/4
1800 0.43~0.55 0~0.1 1830 150 50×11/1640A 32A 16 32×11/32
32A 25A100 50A 12 25×9/32
300 300 125 65A
15×1/2
1140 0.43~0.55 0~0.1 1520 150 250 250
250 150
20×3/8
680 0.43~0.55 0~0.1 1220 150 25A 20A 9 20×9/32100 40A
9 20×3/1620A 20A75 32A
20×5/16
320 0.22~0.5 0~0.1 920 150 220 120
220 120
20×3/16
140 0.22~0.5 0~0.1 920 150 20A 20A 9 20×5/3275 32A
Port dia.x Orifice
90 0.15~0.55 0~0.14 920 150 220 120
(mm) (mm) (mm) (mm)
9 20×1/875 32A 20A 20A
(mm) Port dia.x Orifice
G H Wall thickness
TrapHigh pressure Low pressure
E FCondensate under 0.5MPa (kg/h)
Pressure range of trap (MPa) A B
High pressure Low pressure (mm) (mm)(mm) (mm)
ST-01-35F-105A・B
C-5STEAM PIPINGFLASH TANK
72
C D
(1kg/cm2≒0.1MPa)
Am
ount
of l
ow-p
ress
ure
stea
m g
ener
ated
(kg)
Hig
h pr
essu
re c
onde
nsat
e (k
g)x
100(
%)
Humidifying
Regenerator
Flash tankHigh pressure header
Low pressure header
High
Low pressure steam trap
Higher pressure trap
Lower pressure trap
Not to exceed 1,500
Lower pressure steam
Low pressure return water
Relief valve
Flash tankSame dia. as trap i / lHigher pressure
condensate return
Dirt legDrain cock Pressure on higher pressure side
2
Flash steam
Steam pressure on lower pressure side -
A. Direct-operated (figure on the right shows outer sensor type using pressure detection tube)Operation: Valve is directly regulated by expansion/contraction of control spring (the force of spring is balanced against downstreampressure)Chracteristics:1. Simple structure, compact, light-weighted2. Applicable to a limited range of flow3. As upstream flow or pressure fluctuates
downstream pressure tends to deviatefrom preset pressure ("offset")
Application:Small-sized equipment with less load fluctuations
B. Pilot-controlled Operation:Valve is regulated by the force of steamCharacterictics:1. Complicated structure, large-sized,
expensive. Easily affected by any dirt which enters valve
2. Applicable for a wide range of flow3. Offset is less likely to occurApplication:Steam piping, general equipment (not small-sized, load fluctuations)In general, pilot-controlled type valve is commonly used for steam piping.
C. Parallel arrangement* Applicable where downstrempressure largely fluctuates.Or use this arrangement as a spareunit.
D. 2-step reducing* Applicable where intended down-stream pressure cannot be obtainedor downstream pressure cannot bekept constant with a single pressurereducing valve.
[Note](*) Unit should be pre-assembled(*) Specification of pressure reducing
valve, other valves, strainershould be mentioned in the drawing.
(*) Relief pipe of safety valve shouldbe extended to safe area outside
ST-01-36E-106-A・B・C・D
DSTEAM PIPING
PRESSURE REDUCING VALVE UNIT73
Over 3,000
Over 3,000
Over 3,000
not to exceed 200
not to exceed 200
Equalizer
Downward safety valve
(* See [Note] below)
(*)
(*)
Should be pre-assembled
Bypass pipe diameter --- 1/2 of upstream pipe
Bypass pipe diameter --- 1/2 of upstream pipe
Bypass pipe diameter --- 1/2 of upstream pipe
safety valve
safety valve
safety valve
Over 6m away from each other
(*)
(figure on the right shows internal sensor
A. Mounting positionMeasuring device should be mounted around equipment below: B. SpecificationO --- Normally installedΔ --- If necessary Pressure/compound gauge
--- Normally unnecessary Shape --- roundScale/pointer --- easy to read(operating pressure should be indicated
with red line)Size --- dia 100φ-150φGage cock --- durable handle, no steam lossSize --- dia 75φ-100φ* rimless tipe
Max scale --- 150% of operating pressureGauges should be connected with siphon pipe
* Measuring device is not necessary for below:1. Trap unit of supply header2. In/outlet of radiator body
C. Installation(1) When automatic valve is installed (2) Around header
● Pressure differential before/aftertrap can be measured
● Operating state of automaticvalve can be observed
● Pressure on primary side can bemeasured but operating state of AV or trap cannot be observed
-Outlet - - O -
Boiler water feed pump
Inlet - -
Trap on main drainpipe
Pipe end - - - OVertical - - - -
Main pipe end Vertical OHorizontal Δ Δ
O -
- Δ- O
- OVacuum pump Tank - -Outlet - -
OHumidifier Inlet(steam spray)
-
- ---
- Δ
Booster heaterInlet O
Outlet - -
-Return - - Δ -
- -
Return -
A/C heater Inlet OOutlet -
Heat exchanger Inlet O
- -
High pressure header
Supply O -
Low pressure header
Supply O -
-Boiler
ST-01-37
-
Inlet - - -Outlet O
Steam ReturnPressure Gauge
Compound Gauge
Pressure Gauge
Compound Gauge
F-107-A・B・CE
STEAM PIPINGSTEAM PRESSURE GAUGE
Outlet - --Δ
-
--
- -- O-
74
Heat source
Load side
Remarks
Hexagonal Square Rounded Round (wrench
(Gauge connectig port)
Rimless Fully rimmed Semi-rimmed Insert
(Gauge shape)
Max.1,900
Bushing
Socket
(3) Low pressure steam
(4) High pressure steam
(5) Installation
ST-01-38F-107-C
ESTEAM PIPING
STEAM PRESSURE GAUGE75
Hot
wat
er su
pply
Hot
wat
er su
pply
Hea
ting
Hea
ting
Hea
ting
Hea
ting
"
"
A/C Direct heating
Booster heater
Symbol
Pressure gauge Compound gauge
Pressure reducingvalve
Pressure gauge should be installed in the following cases:● When it is necessary to distinguish circuits in summer/wintertime.● Pressure is reduced in each circuit
Air
Kitc
hen
Kitc
hen