Post on 15-May-2020
KEY DESIGN CHARACTERISTICS
MULTIPLE-STEP AXIAL FLOW HIGH RESISTANCE TRIM
78000 design is based on the principle of multi-step high resistance axial flow. Pressure reduction occurs along the
length of the plug through a series of throttling stages, designed to divide the total drop equally between the trim
elements or steps (assuming incompressible flow throughout), No individual stage is ever exposed to the full pressure
differential and as a result, trim life is greatly extended. In addition, the fluid takes a tortuous path. This adds
resistance and therefore velocity head loss.
LOW PRESSURE RECOVERY
The valve trim is designed to reduce pressure recovery (exhibits high C ); to lessen chances of vaporization at the
orifice; and consequently, eliminates cavitation for liquid service and contributes towards reduction of noise for all
fluids. When the plug is in the wide-open position, the fluid velocity is nearly constant through the trim. The tortuous
flow path adds significantly to the overall pressure losses. In the wide-open position, ideal conditions are approached:
that is, continuous pressure drop and no appreciable recovery. At this point, the C is practically equal to 1. At reduced
lift positions, the throttling mechanism is similar to a piping system with a number of single stage valves in series. Each
stage throttles a portion of the total pressure drop with an increase in velocity and subsequent pressure recovery.
Overall pressure recovery factor varies with the number of stages and please refer page 8 for the total Pressure
Recovery factor (C ) for each size.
TIGHT SHUT-OFF & SEAT PROTECTION
Protection against seat erosion is ensured by provision of ANSI/FCI 70.2 Class V seat shut-off when standard metal seats
are furnished. Pressure reduction is accomplished between the multi-step plug & the liner and not across the seat ring.
Thus in any severe service, seat ring damage due to high pressure drop can be ruled out.
SPECIAL SOFT SEAT DESIGN
Bubble tight leak tightness as per ANSI/FCI 70.2 Class VI can be achieved when optional soft seats are supplied. The
special seat ring with sliding collar shelters the resilient insert from the high-pressure fluid, when the valve opens.
HIGH-PERFORMANCE MATERIAL IS STANDARD
78000 series high pressure valves are manufactured from solid steel forgings to assure material integrity. Castings also
available as option. Without exception, the material specified as standard have been tested and selected to provide
trouble free operation in services with high pressures and erosive fluids. The high performance trim material
employed ensures durability of the valve for any severe application. Special trim material available for NACE and
corrosive application.
HIGH ALLOWABLE PRESSURE DROPS
With balanced trim design for sizes 2” through 6”, a wide range of allowable shut -off pressure drops is available with
conventional spring diaphragm actuators.
VARIETY OF BODY CONFIGURATION OFFERINGS
A standard angle body and optional in-line body styles are offered to accommodate a variety of piping requirements.
SIMPLE TRIM MAINTENANCE
The multiple step trim, made from specially chosen hard material gives maximum service life and the quick change
seat ring design provides ease of trim replacement.
LARGE FLOW AREA
Because of their relatively large flow passages and shearing action provided by the multiple stage plug & cage
designs, these valves are particularly well suited for applications involving fluids with entrained particles.
f
f
f
1
Leakage Class / Temperature Range(3)
Class IV : 0.01% of maximum rated capacity at 50 psig to atmosphereClass V : 5 x 10 ml/min of water per inch of orifice diameter per psi differentialClass VI: Bubble Tight as per ANSI/FCI 70.2
Special Designs available for applications outside the given temperature range, consult MIL
4
(3) :
Valve Size(Inch)
2 through 6
TypeTemperature Range
(Deg.C)
UnbalancedMetal Seat
BalancedMetal Seat
Soft Seat
-29
-29
-29
260
232
204
IV
IV
V
V
VI
Seat Leakage Class(As per ANSI/FCI 70.2)
1 through 6
1 through 6
PRESSURE DROP DIAGRAM OF A CONVENTIONAL VALVEIN CAVITATING SERVICE
(Pressure drops below the vapour pressure at thevena-contracta and then recovers, resulting in cavitation.
P1
P2
PV
78000 PLUG AT FULL OPEN POSITION(Continuous pressure drop & no appreciable recovery)
P1
P2
PV
3
Detail of thePTFE Soft-Seat Ring
PTFEInsert
78000 SERIES UNBALANCED PLUG CONSTRUCTION
Metal Seat
20
18
16
1512
1917
1
13
8
5
4
2
3
6
710
11
9
4
Material of construction(4)
(4): For other material consult MIL: Refer page 6, For sizes 2" through 6" only: Refer page 6, For balanced construction only, sizes 2" through 6"
(5)
(6)
Alloy Steel ASTM A 182 Gr. F11 / F22
St. Steel 17.4 PH ASTM A 564 Gr 630, Cond H 1075
Alloy Steel ASTM A 193 Gr. B7
St. Steel ASTM A 194 Gr. 8
Carbon Steel ASTM A 105
St. Steel ASTM A 479 Ty 304
St. Steel ASTM A 479 Ty 304
PTFE
Carbon Steel ASTM A 105
Stainless Steel ASTM A 182 Gr. F316
Alloy Steel ASTM A 193 Gr. B7
Alloy Steel ASTM A 194 Gr 2H
SS 304 + Asbestos or Graphite (spiral wound)
ASTM A 276 Ty. 420 (Roll Pin), SS 316 (Plug Pin)
Drawing
Ref. No.
Part Name Standard Material
1
2
3
4
5
6
7
8,18
8BS
8BF
9
10
11
12,13
14
15
16
17
19
20
Valve Plug Stem
Packing Flange Stud
Packing Flange Nut
Packing Flange
Packing Follower
Packing Spacer/Lantern Ring
Gland Packing
Bonnet, Body
Carbon Steel ASTM A 105Bonnet Flange(5)
Carbon Steel ASTM A 106 Gr. BBonnet Spacer(5)
Body Stud
Body Nut
Body Gasket
Roll Pin, Plug Pin
Balancing Seal Set(6)
Plug
Seat Ring
Seat Ring Gasket
<180 C0
GRAPHITE>180 C0
Spring energised Carbon Filled PTFE
Liner St. Steel 17.4 PH ASTM A 564 Gr 630, Cond H 1075
Spacer St. Steel 17.4 PH ASTM A 564 Gr 630, Cond H 1075
St. Steel 440 C ASTM A 276 Ty 440C, Hardened
St. Steel ASTM A 479 Ty 316+ Stellite No. 6 or PTFE
SS 304 + Asbestos or Graphite (spiral wound)
< 232 C0
5
78000 SERIES BALANCED PLUG CONSTRUCTION
18
16
15
12
1917
1
13
8
8BS
8BF
5
4
2
3
6
7
10
14
9
6
Optional Material for Corrosive Service(4)
Inconel X 750 ASTM A 461 (HRC 35 max.)
Alloy Steel ASTM A 193 Gr. B7
St. Steel ASTM A 194 Gr. 8
Carbon Steel ASTM A 105
St. Steel ASTM A 479 Ty 304
St. Steel ASTM A 479 Ty 304
Carbon Steel ASTM A 105
Carbon Steel ASTM A 105
Stainless Steel ASTM A 182 Gr. F316 (HRC 22 max.)
Alloy Steel ASTM A 193 Gr. B7
Alloy Steel ASTM A 194 Gr 2H
SS 304 + Asbestos or Graphite (spiral wound)
ASTM A 479 Ty 316
Spring energised Carbon filled PTFE
Drawing
Ref. No.
Part Name Standard Material
1 Valve Plug Stem
Packing Flange Stud
Packing Flange Nut
Packing Flange
Packing Follower
Packing Spacer/Lantern Ring
Bonnet, Body
Bonnet Flange(5)
Carbon Steel ASTM A 106 Gr. BBonnet Spacer(5)
Body Stud
Body Nut
Body Gasket
Roll Pin, Plug Pin
Balancing Seal Set(6)
Liner
Spacer
Plug
Seat Ring
Seat Ring Gasket
PTFE
GRAPHITEGland Packing
Ferralium 255, ASTM A 351 Gr. CD4MCU or
Ferralium 255, ASTM A 351 Gr. CD4MCU or
Inconel X 750 (HRC 35 max.)
Inconel X 750 (HRC 35 max.)
Nitronic 60, ASTM A479 Type S21800 with
HF on seat & guide area (HRC 35 max.)
St. Steel ASTM A 479 Ty 316+ Stellite No. 6 or PTFE
SS 304 + Asbestos or Graphite (spiral wound)
Monel K500 or
Monel K500 or
Nitronic 50, ASTM A479 Type XM19 withHard facing on seat area or
(4): For other material consult MIL, Certification to NACE MR01-75, Latest revision available(5)
(6)
: Refer page 6, For sizes 2" through 6" only: Refer page 6, For balanced construction only, sizes 2" through 6"
2
3
4
5
6
7
8,18
8BS
8BF
9
10
11
12,13
14
15
16
17
19
20
<232 C0
7
0
100
0 100
Flow Coefficients - Rated Cv, Critical Flow Factor - Cf
ValveSize &Rating
Travel(Inch)
MinimumOperable
Cv
Liquid Gas orSteam
OrificeDia
(Inch)
Trim Type
Cf Cf Cf CfCv Cv Cv Cv
A B B+
0.500
1.00
1.875
3.250
3.250
3.250
3.250
0.6 0.9850.992
0.991
0.991
0.988
0.988
0.988
0.9, 1.1 - 0.750.970
3.6, 4.5
12, 15
40, 55, 70*
40, 55, 70*
70, 110
55
0.982 0.970 3.5
13
40
40
60
40
0.970
0.970
0.970
0.970
0.970
0.982
0.978
0.978
0.978
0.978
2.4
8
30
30
30
0.03
0.06
0.12
0.61
0.61
1.5
0.61
0.125 0.998
0.997
0.997
0.997
0.997
- - - -
0.997
0.25
0.50
0.88
0.88
0.88
0.88
0.1, 0.3
1.2
4
15
15
15
1" 2500#<
1.5" 2500#<
2" 2500#<
3" 2500#<
4" 2500#<
6" 600#<
6" 900#>
8
* Cv-70 with cast body upto ANSI Class 600#
Trim Characteristic
78000 series valves have an inherent Mod. Linear characteristic, integrating the clearance flow concept over 10% of the initialvalve travel to avoid high pressure drops in the seating area and throttling at low lifts. The 10 to 100% of the travel ensuresprecise control.
Actuator Selection for 78000 series unbalanced valves
ValveSize
Stroke(inch)
Act.Size
Air to Open (38)
SpringRangePsig
SupplyPress.Psig
Shut off Pressure
Kg/cm2
SpringRangePsig
Shut off Pressure
Kg/cm2
1
1.5
Max.RatingANSI
Air to Close (37)
V VVI VI
250025 210 210 210 21012-16
18-22
14-20
24-30
16-25
23-33
15-25
18-30
15-25
18-30
15-25
18-30
420 420 420 420
210 210 175 175
420 420 316 316
70 70 35 35
140 140 60 60
28 28 17 14
70 63 28 21
28 28 17 14
70 63 28 21
28 28 17 14
70 63 28 21
30
30
50
40
60
30
60
30
60
30
60
2500
2500
2500
2500
2500
0.125
0.25
0.5
0.88
0.88
0.88
13
15
15
18
18
18
6-10
6-10
6-12
6-12
6-16
6-16
3-15
3-15
3-15
3-15
3-15
3-15
Actuator Selection for 78000 series balanced valves
ValveSize
Stroke(inch)
Act.Size
Air to Open (38)
SpringRangePsig
SupplyPress.Psig
Shut off Pressure
Kg/cm2
SpringRangePsig
Shut off Pressure
Kg/cm2
2
3
Max.RatingANSI
Air to Close (37)
V VVI VI
250035 210 210 210 21016-25
23-33
15-25
15-25
15-25
18-29
18-29
18-29
420 420 386 344
210
210
210
210
210
210
140 77
77
77
420
420
420
330
330
330
228
228
228
109
109
109
140
140
45
50
50
50
60
60
60
2500
2500
2500
0.5
0.88
0.88
0.88
15
18
18
18
6-16
6-16
3-15
3-15
3-15
3-15
3-15
3-15
2
3
4
6
4
6
9
Dimensions (mm)
10
VALVEANGLE VALVE INLINE VALVE
BUTT & SOCKET WELDBUTT WELD
A A AB B BH H H
SOCKET WELDSIZE(inch)
1 95
119
165
225
165
220
205
104
119
178
235
178
226
271
179
217
283
375
283
336
376
65
80
100
150
-
-
-
101.5
117
163
216
-
-
-
179
217
283
375
-
-
-
220
300
394
394
430
610
575
58
51
71
71
71
108
91
183
223
259
259
298
417
427
1.5
2
3
4X2
4X3
6X3
B
H
A
50
0(m
in)
B
H
A
50
0(m
in)
A
BH
50
0(m
in)
A
BH
50
0(m
in)
All dimensions in mm
Face to Face dimension tolerance 2mm+
Approximate dimensions of 78000 series Forged Valves, 2500#ANSI
Body
Bonnet
Trim
Type
Type
A(Liquid)
B+(Liquid)
B(Liquid)
Gas or Steam
Special
Yes
Yes
No
No
Type
Type
Type
Plug
Seat Ring
Type
Angle
Rating
Connection
Material
Material
Material
Material
Guiding
Size Refer Page 8
Refer Page 8
Flanged Butt-Weld Socket-Weld
Inline
Refer Page 5,7
Refer Page 5,7
Refer Page 5,7
Refer Page 5,7
Refer Page 2
Refer Page 9
Refer Page 9
Close Open Stayput
Refer Page 5,7
Unbalanced
Clamped
Liner
Balanced
Standard
Lubricator
Packing
Liner&Spacer
Flow Direction Flow to Open
IV V VI
Model Number
Leakage Class(ANSI/FCI 70.2)
Air to Open Air to Close
With Bellow Seal
Hand Wheel
Action
Air Failure
Actuator Size
Actuator
Actuator Spring Range
Accessories & Special Requirements
Pneumatic Spring Diaphragm
Piston Cylinder Manual
Electrical
FLUID PHASE
Required Parameters
LiquidSteam
Flow Rate (Start-up/Min/Nor/Max)
Inlet Press. (Start-up/Min/Nor/Max)
Outlet Press. Start-up/Min/Nor/Max)
Shut-off Pressure
Temperature
Specific Gravity or Density or Mol. Wt.
Vapour Pressure
Critical Pressure
Viscosity
Compressibility Factor
Specific Heat Ratio
Inlet & Outlet Pipe Size/Schedule
GasTwo-Phase
Liquid Gas Steam
Specification Data
Checklist below contains the necessary data to specify the basic 78000 series control valve. The pagereference will guide you to the appropriate sections when a selection is to be made. For accessoriesand special options, consult your MIL representative
Application Data
Checklist below provides a convenient means for listing all the process data required to properly size your 78000series control valve.
11
Working Temp
0F
100 38 20
ANSI 150#
WC9 WC9 WC9 WC9 WC9 WC9CF8M CF8M CF8M CF8M CF8M CF8M
ANSI 300# ANSI 600# ANSI 900# ANSI 1500# ANSI 2500#
19 53 51 105 101 158 152 264 253 440 422
363440
328427
301414
280390
264354
260345
255333
250312
248297
286 245
263 243
221 226
153
102
205
201
264 218
256 197
248 181
234 168
213 159
207 156
200 153
187 150
179 148
171 147
158 146
133 136
92
62
123
121
158 131
154 118
149 108
140 101
128 95
124 94
120 92
112 90
107 89
103 88
95 88
79 82
55
37
74
72
105 87
102 79
99 72
94 67
85 63
83 63
80 61
75 60
71 59
69 59
63 58
53 55
37
25
49
48
53 44
51 39
50 36
47 34
43 32
41 31
40 30
37 30
36 30
3034
2932
2726
18
12
25
24
18 17
16 15
14 14
12 12
10 10
9 9
8 8
7 7
6 6
5 5
4 4
2 2
1
1
1
1
93
149
204
260
316
343
371
399
427
454
482
510
537
565
200
300
400
500
600
650
700
750
800
850
900
950
1000
1050
0C
Max. Working Pressure in Kg./ cm2
Working Temp
0F
100 38 20
ANSI 150#
WCC WCC WCC WCC WCC WCCWC6 WC6 WC6 WC6 WC6 WC6
ANSI 300# ANSI 600# ANSI 900# ANSI 1500# ANSI 2500#
20 53 53 105 105 158 158 264 264 440 440
440 440
427 427
414 414
390 390
354 354
345 345
333 333
295 312
241 297
157 263
101 187
60 127
30 30
264 264
256 254
248 244
234 234
213 213
207 207
200 200
177 187
145 179
94 171
60 158
36 112
18 76
158 158
154 152
149 146
140 140
128 128
124 124
120 120
106 112
87 107
57 103
36 95
22 67
11 46
105 105
102 102
99 97
94 94
85 85
83 83
80 80
71 75
58 71
38 69
24 63
14 45
7 30
53 53
51 51
50 49
47 47
43 43
41 41
40 40
36 37
29 36
19 34
12 32
7 23
4 15
18 18
16 16
14 14
12 12
10 10
9 9
8 8
7 7
6 6
5 5
4 4
2 2
1 1
93
149
204
260
316
343
371
399
427
454
482
510
537
200
300
400
500
600
650
700
750
800
850
900
950
1000
0C
Max. Working Pressure in Kg. /cm2
Other useful information
Maximum working pressure for standard material (as per ASME B 16.34 - 1996)
FUNDAMENTAL DEFINITIONS
FLOW COEFFICIENT (Cv): Cv, which is universally accepted as a yardstick of control valve capacity is defined as thenumber of US gallons per minute of water at 60F that will pass through a given flow restriction with a pressure drop of1 psi. For example, a control valve, which has a maximum Cv of 16, has an effective full port area which allows flow of16 gallons per minute of water with 1 psi pressure drop.
CRITICAL FLOW FACTOR (Cf): Cf is a dimensionless expression of the pressurerecovery ratio in a control valve. As the fluid flows through a valve orifice, there isa marked increase in velocity. Increase in velocity is accompanied by a decrease inpressure. Velocity reaches a maximum and pressure it's minimum at the smallestcross-sectional flow stream area downstream of the orifice (vena contracta).Downstream to the vena contracta, the fluid decelerates and consequently thepressure recovers, hence the term pressure recovery.
P1: Valve Upstream PressureCf= P1- P2 P2: Downstream Pressure
P1-Pvc Pvc: Vena Contracta Pressure
PRESSURE
VELOCITY
VE
LO
CIT
Y&
PR
ESSU
RE
P2P1
VENA CONTRACTA
12