A Long Experience in Energy Equipment and one Goal:
T h e C u s t o m e r ’s s a t i s fa c t i o n .
E N E R G Y
VALVITALIA reserves the right to change design, specification and materials without notice
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N E E D
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CONTENTS
Globe Control Valves
LTG1
LTG2
LTG3
LTG4
LTG5
RV631
4
4
6
8
9
18
Tree-way Control Valves
TRV1
TRV2
10
10
Rotary Control Valves
DYNA-LOK
K-LO
CB-54
CB-55
12
14
16
16
Steam Conditioning Control Valves
PRDV
SAN nozzles
20
22
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VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
LTG1 and LTG2 Control Valves
Globe straight-way, single seat LTG1 and LTG2 series are very versatile control valves of
general use for any applications under moderate p/T service conditions. LTG1 is the
standard design with screwed seat ring while LTG2 is the corresponding quick-change
version with the same flow coefficients and pressure differentials capability.
Due to their simple construction and to their large range of available materials these
valves are suitable for a wide range of applications, such asr corrosive, dirty, sticking and
slightly abrasive fluids. Angle-body LTA special design is also available with the same
trims of LTG series.
Main advantages:
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Excellent plug stability provided by heavy top guiding
design
Interchangeable low noise and anticavitation trim either
for std or quick-change design
Tight shut-off class V and VI also available
Wide flow range capability is allowed by a great number
of reduced capacity trims
LTG2 ANSI 300
Diaphgram Actuator
Technical characteristics:
Body:
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Bonnet:
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Trim:
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Packing:
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Sizes: 3/4”, 1”, 1”1/2, 2”, 3”, 4”, 6”
Ratings: up to ANSI 600 /PN100
Flanged, butt-welded, SW, and threaded
Cast construction, also wrought or by bar for smaller dimensions
Face-to-face dimensions as per IEC 60534 –3-1
materials: carbon, Cr-Mo and AISI 316 stainless steel
Flow direction: – to open.
– to close for some flashing applications
Materials: Carbon, Cr-Mo and Stainless Steels
Bolted to body
Extended for high and low temperatures
Bellows seal
Special design for cryogenic applications
Same materials as body
Top guided plug both in LTG1 and LTG2 constructions
Linear, modified linear and Eq% flow characteristics
Plug types: – contoured
– flat disc for quick opening operation
– skirted and drilled BRD design (linear characteristic) for special services
– soft seat - only for contoured and flat disc
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Adjustable by nuts and follower
Seal rings: reinforced braided teflon or pure graphite split-rings
Bellows seal
Rangeability:
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Cvmax / Cvmin better than 50:1 for 1" port and over
Cage (LTG2 only):
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Seat ring clamped into the body by the cage for quick-change feature
Large windows of cage do not affect the inherent flow characteristic
(including max Cv) of LTG1 corresponding trims
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VALVITALIA reserves the right to change design, specification and materials without notice
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Seat Ring:
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Threaded in LTG1 model and clamped-in in LTG2 model
Leakage Class
(IEC 60534-4) :
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Standard: class IV
Optional: class V and VI
Actuators:
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Pneumatic diaphragm or Piston type
Electric and Electro-Hydraulic actuators
LTA design
Globe types LTG1 and LTG2 are also available with angle body.
In this case they are designated as LTA1 and LTA2 Control Valves.
LTA series are special engineered designs. The advantages provided by LTA series
are the following:
1 - Different dimensions for valve inlet and outlet are available
2 - Inlet and outlet ratings can also be different
3 - Centre-to-face dimensions consistent with IEC standard when the connections have
the same dimensions
4 - Increased Cv values in comparison with LTG1 and LTG2 standard body style due to
less pressure drop of angle path
5 - Trims, characteristics, material and actuators are the same of standard LTG series
LTG1 ANSI 600
Electric Actuator
LTA Control Valve
Standard contoured plug
LTG1 Std contoured plug
BRD trim
Soft seated plug
LTG2 Std contoured plug
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VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
LTG3 Cage Control Valves
Globe straight-way LTG3 series is a very versatile control valve for the main applications.
Its high performance derives by using a balanced and cage-guided plug. LTG3 is particularly suitable for heavy duties and for any other application under most demanding
service conditions. Due to their simple construction, to the large range of trim types and
available materials, these valves are suitable for a wide range of applications, including
also high temperature and corrosive fluids, severe low-noise requirements and sour
service in accordance with NACE standard.
Main advantages:
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High pressure drop capability with no practical limitations
Improved plug stability due to large guiding areas
Wide-range capability is allowed by a great number
of reduced capacity trims
Excellent noise attenuation with low-noise
single-stage trim for gas and steam service
Improved cavitation protection on liquid services
Multistage trims also available for cavitation control.
Balanced plug construction reduces thrust and
actuator sizes
Piloted plug construction for tight shut-off up to
class V in high temperature services
LTG3 20” ANSI 900
LTA design
LTG3 are also available with angle body. In this case they are designated as LTA3 Control Valves.
LTA series are special engineered designs. The advantages provided by LTA design are the same of LTA1 series.
Technical characteristics:
Body:
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Bonnet:
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Trim:
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Cage:
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Sizes: 2", 3", 4", 6", 8", 10", 12", 14", 16", 18", 20"
Ratings: up to ANSI 150, 300, 600, 900, 1500, 2500 and equivalent PN
Flanged, butt-welded, socket-welded and threaded
Cast standard construction; wrought or bar for 2" and 3" sizes
Face-to-face dimensions as per IEC 60534-3-2 - long series
materials: carbon, Cr-Mo and AISI 316 stainless steel
Flow direction: – to open - general feature
– to close - for piloted plugs and some flashing services
Materials: Carbon, Cr-Mo and Stainless Steels
Standard or extended type either for high or low temperature applications
Bolted to body
Same materials as body
Balanced and fully cage-guided plug
Unbalanced design for small ports or low pressure drop applications
Piloted design for tight shut-off associated to high fluid temperature
Plug seal rings: PTFE, metal or metal and graphite
Low-noise drilled cage single stage LN and special ELN type
with additional acoustical benefit of 4 dB.
MPS multistage trim special design for high pressure drops
Multi-cage construction up to 6 stages. 7 stages and over
are obtained from a solid disk stack
Linear and equal% characteristics for standard trim design
VALVITALIA reserves the right to change design, specification and materials without notice
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LTG3 balanced plug
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Seat Ring:
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Quick-change and free-expanding type, precisely coupled
to the cage to ensure a perfect plug alignment
Leakage Class:
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Classes III, IV, IV S1 and V according to IEC 60534-4
Class VI is also available with soft-seat
Actuators:
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Pneumatic diaphragm or Piston type
Electric and Electro-Hydraulic actuators
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Single stage
Low noise cage
MPS trim
balanced plug
LTG3 plug with soft insert
Low noise cage construction
Linear characterized LTG3 cages
MPS multistage trim
LTG3 - cage assembling
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Double stage
balanced plug
LTG3 - control valve under cryogenic test
VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
LTG4 Series Control Valves
Globe straight-way LTG4 Series Control Valves have the same body, bonnet and seat ring
of LTG3 series. The main difference is the design of the plug which is balanced type and
contoured shaped for the throttling function. The cage, provided with large windows,
clamps the seat ring against the body and acts also as the integral guide of the plug.
The trim is of quick change type for an easy maintenance. These valves combine the benefits of plug balancing and quick-change feature of LTG3 series with the simple and versatile construction of contoured plug which allows a wide selection of materials, coatings and
flow characteristics. Also dirty, abrasive and very corrosive fluids can be successfully
handled without the inconvenient sometime occurring in conventional throttling cage valves. The limitations about low-noise and anticavitation characteristics are compensated by
the free-passage shape of the plug with reduced risk of local erosionand clogging.
Technical characteristics:
Body:
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Bonnet:
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Trim:
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LTG4 10” ANSI 2500
Flanged, butt-welded
Cast std construction; also wrought or bar construction for 2" and 3" sizes
Face-to-face dimensions as per IEC 60534-3-1 long series
Sizes: 2", 3", 4", 6", 8", 10", 12", ratings up to ANSI 150, 300, 600, 900, 1500, 2500
Materials: Carbon, Cr-Mo and Stainless Steels
materials: carbon, Cr-Mo and AISI 316 stainless steel
Flow direction: to open
Bolted joint to body
Extended type either for high and low temperature applications
as a standard feature
Same materials as body
Balanced and fully guided plug
Seal rings for leakage classes IV and better: metal, teflon, metal and graphite
Linear and equi% up to 2” port included - modified linear for higher sizes
Plug types: – contoured
– flat disc for quick opening operation
– soft seat
– soft seat
– cascade trim
Seat Ring:
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Quick-change and free-expanding type, precisely coupled
with the cage to ensure a perfect plug alignment
Leakage
Class:
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Classes III, IV, IV S1 and V according to IEC 60534-4
Class VI is also available with soft-seat plug
Actuators:
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Piston or pneumatic diaphragm spring return
Electric actuators on request
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Cascade trim
Represents one of the most valid systems to reduce erosion and cavitation and it finds wide applications in
small size valves, whether other “multistep” solutions
can not be used. The pressure drop is equally splitted
through a lot of labyrinth paths specially machined inside the trim itself. Control valves equipped with “cascade trim” can operate under very high pressure drops
with a longer working life compared to standard single
stage trims. Two separate sealing surfaces can be provided: by this way the first seal, between seat and cage,
acts as a sacrifice element.
VALVITALIA reserves the right to change design, specification and materials without notice
LTG4 - cascade trim
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LTG5 Series Control Valves
LTG5 Series top guided control valves are specially designed for the control of particular
fluids where dead zones inside the valve body are not tolerated due to risk of crystallization, local corrosion, scaling or seizure. These features pertain to top guided LTG1 series,
but a different plug-to-stem solid construction is performed in LTG5 valve to avoid any
residual areas where fluids can stagnate. Particular care is paid to the packing zone where
stagnation of fluid could cause stem corrosion, wear and leaks. Cv and other sizing factors
are the same of LTG1 series. Typical applications of these valves are:
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Food industry and drinking water
Pharmaceutical processes
Urea, melamine and similar plants
Main features:
1 - No dead zones inside the body with reduced contamination and erosion
2 - Stem-to-plug solid design which:
– avoids dead zones inside the bonnet including packing box chamber
– avoids coupling stem–to–plug which can be affected by local
corrosion and consequent loosening
– provides an excellent alignment between stem and plug with
benefit for the packing tightness
– increases trim stiffness due to oversized stem diameters
3 - reduced distance from packing to body inside cavity keeps the packing
temperature very close to that of internal fluid so to prevent solidification
inside the packing
LTG5 high pressure
lug body type
for urea service
Technical characteristics:
Body:
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Bonnet:
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Trim:
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Flanged and butt-welded connections –also plug type is available
Cast construction – also wrought or by bar for small dimensions
Face-to-face dimensions as per IEC 60534-3-1 long series
Sizes: 3/4”, 1”, 1”1/2, 2”, 3”, 4”, 6”
Ratings up to ANSI 600 – ANSI 1500 for sizes up to 2” included
Materials: carbon, Cr-Mo, AISI 316, AISI 316L, duplex,
hastelloy for sizes up to 3” – other on request
Flow direction: – to open
– to close only for balanced plug
Flanged to body
Same materials as body
seal rings: reinforced braided Teflon or pure graphite
Top guided unbalanced plug – integral with stem
Guide: an extra-long bush fitted into the bonnet
Flow characteristic: linear and equi% up to 2” port included
modified linear for higher sizes
Type of plug: contoured or flat for quick opening operation
Soft seat: teflon insert fitted into the plug
seat ring: threaded in std design – also welded-in or integral
for high corrosive services
Materials:
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Inox, hastelloy, duplex, HVD1, other alloys and coatings
on request and when necessary
Leakage
Class:
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Std IV – optional V or VI
Actuators:
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Pneumatic diaphragm or piston types
Electric and electro-hydraulic on request
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VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
TRV1 and TRV2 3-way Control Valves
TRV control valves series are especially designed for heat exchangers control where the flow rate of the heating
fluid which enters the heat exchanger is changed by the temperature controller. As outlined in the sketches of
Fig.1 and 2 both the two methods used for this process switch-off the flow rate into a by-pass line around the
exchanger. In the layout of Fig.1 the valve is the diverting type TRV1 with one inlet and two outlets while in the
arrangement of Fig 2 the valve is the mixing type TRV2 with two inlets from heat exchanger and by-pass. The use
of the by-pass around the exchanger limits the changes of pressure in the main line with many benefits for the
assisted final equipment (boilers, headers, etc.).
Fig.1 – DIVERTING TYPE 3-way control
valve in heat exchanger application
Fig.2 – Mixing type 3-way control
valve in heat exchanger application
TRV Design
In both designs the fluid tends to open the plug to ensure the max stability to the valve operation. The selection
between the two solutions is basedprincipally on fluid temperature and on the differential temperature T1-T2 across
the exchanger. TRV1 diverting type is generally preferred for high ⌬T(120° and over) but when T1 exceeds 350°C
(up to 450°C) mixing type TRV2 is preferred. Generally, mixing type is preferred as it is less expensive and
due to easier maintenance.
Technical characteristics:
Body:
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Bonnet:
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Trim:
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Sizes: from 1" up to 12"
Ratings: up to ANSI 150, 300, 600
900 and 1500 on request
Flanged connections
Cast standard construction; wrought or bar construction
also available for small sizes
Flow direction: see sketckes
Materials: carbon, Cr-Mo and stainless steels
Plain or extended type either for high or
low temperature applications as a standard feature
Bolted to body
Same materials as body
Intrinsically balanced in heat exhanger application
Plug is available in two design: standard and low-noise
TRV2 Control Valve
12” ANSI 600 (mixing type)
VALVITALIA reserves the right to change design, specification and materials without notice
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VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
DYNA-LOK rotary Control Valves
DYNA-LOK rotary control valves are provided with a double eccentric disc and a very
easy-to-be changed TFE based or metal seat ring. Thanks to DYNA-LOK disc off-set
design, the torque tending to close the valve and, more in general the torque needed
to control the disc rotation is sensitively reduced. In addition, the cam effect performed
by second shaft eccentricity guarantees a seal ring longer life. These valves can offer a
great flow control with an excellent shut-off withstanding also very high pressure drops,
independently of the flow direction.
Technical characteristics:
Body:
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Disc:
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Shaft:
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Bearings:
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Sizes:
wafer and lug body design: from DN 150 up to DN 2000
flanged body: from DN 250 up to DN 2000
Ratings: up to ANSI 300, PN 40 up to DN 600 included, ANSI 150, PN16 for greater sizes
For water mains DYNA-LOK control valves can be supplied in accordance with AWWA
std ratings and connections
Cast or fabricated construction depending on body style, size and material selection
Face-to-face dimensions as per EN 558, IEC 60534-3-1, ISO 5752
Materials: all carbon and stainless steel grades, duplex and copper alloys
Double eccentric design when tightness in closed position is requested
Full-bore swing-through construction with single off-set disc when no tightness is requested in
closed position
Solid or whrougt cast construction
Bi-directional flow but inlet on flat disc side gives better performance
Flow characteristic: increasing gain up to approx. 50° opening, linear from 45° to max travel
Materials: same as the body
Constructions: one or two pieces depending on sizes
Connection to the disc: by pins protected by set screws
External sealing: single stuffing box actuator side
Packing materials: teflon or graphite seal rings
Materials: stainless steels, 17-4-PH, XM19
Radial bearings: Teflon-based compounds embedded
in SS bushing. Over-sized bearings (total length = 3,5 x ⌽)
allow a smooth rotation and a long maintenance-free valve life
Axial bearings: axial thrusts are held by a couple
of anti-friction washers
High pressure DYNA-LOK
control valve with PRA actuator
Seat Ring:
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Two designs are available to fulfil different temperature conditions:
– spring-energized Teflon ring for temperatures up to 200°C
– SS ring for higher temperatures
Both seal rings are locked inside the body by means of an easily
removable spacer.
Leakage
Class:
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Teflon seal ring assembly is consistent with class V (IEC 60534-4)
for sizes up to 20”. For higher dimensions IVS1 class or better
depending on actuator
For metal SS type IVS1 class is allowed for all sizes
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Actuators:
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VALVITALIA reserves the right to change design, specification and materials without notice
Valvitalia DRA pneumatic diaphragm actuator for valve sizes up to 16”
Valvitalia PRA piston types actuators with low friction scotch-yoke
mechanism for larger valve sizes
Pneumatic rack and pinion both single and double acting for sizes
up 24” included
Electric, electro-hydraulic and hydraulic actuators for heavy duties
control purpose
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C O N T R O L
The requested torque to move the disc of a DYNA-LOK valve is mainly depending
on the differential pressure across the disc and on the values of pressures inside
the body. The ⌬p increases friction of seal ring and shaft bearings in closed
position, while, in opened position, it creates a dynamic force due to a not
balanced distribution of pressures acting on the disc. DYNA-LOK disc design limits
very much this second well-known effect especially in the usual working travel range
from 40° to 90°.
32” DYNA-LOK control valve - lug body construction
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VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
K-LO high-performance Rotary Control Valves
K-LO rotary control valves have been especially designed to meet the usual cavitation problems of processes when hot liquids and not negligible pressure drops
facilitate the development of cavitation. These special valves are deriving from the
double eccentric DYNA-LOK series by modifying the basic disc design with particular
baffles, integral or welded-in on both the disc sides, which increase the recovery
factor of valve as well as its cavitation index grows. These baffles are wing-shaped
and machined with many rectangular windows providing a moderate pressure drop
so to not greatly affect the Cv of the valve with the plain disc. The distribution of the
windows takes into account the presence of the sealing ring fitted into the body,
with particular care to the area close to the shaft axis. Due to particular disc baffled
design, max valve openings greater than the usual 90° are allowed to achieve higher
Cv values. As for DYNA-LOK valves, the off-set design reduces the torque tending to
close the valve. In addition, the cam effect caused by second shaft eccentricity
improves the seal ring life.
Technical characteristics:
Body:
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Disc:
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Shaft:
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Bearings:
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Sizes: from DN 250 up to DN 2000
Ratings: up to ANSI 300, PN 40, up to DN 600 included, ANSI 150, PN16 for greater sizes.
Flanged design (cast or fabricated construction depending on the size and material selection)
Face-to-face dimensions as per EN558, ISO 5752, basic series 13
Materials: all carbon and stainless steel grades, duplex and copper alloys
Double eccentric design when tightness in closed position is requested
Two disc designs are available: drilled wings for low noise services and multi-windows wings for
anticavitating service
Full-bore swing-through contruction with single off-set disc when no sealing device is requested
in closed position
Both sides flow directions. Best leakage performance is assured by flow on flat disc side
Opening up to 100°
High xFZ cavitation index values
Flow characteristic: increasing gain up to approx. 50° opening, linear from 50° to max travel
Materials: same as the body
Constructions: one and two pieces depending on sizes
Connection to the disc: by pins protected by screws
External sealing: single stuffing box actuator side
Packing materials: teflon or graphite seal rings
Materials: stainless steels, 17-4-PH, XM19
Radial bearings: Teflon-based compounds embedded in SS bushing. The oversizing of these
bearings (tot. length = 3,5 x ⌽) allows a smooth rotation and a long maintenance-free valve life
allow a smooth rotation and a long maintenance-free valve life
Axial bearings: axial thrusts are held by a couple of anti-friction washers
Seat Ring:
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Two designs are available to fulfil different temperature conditions:
– spring-energized Teflon ring for temperatures up to 200°C
– SS ring for higher temperatures
Both seal rings are locked inside the body by means of an easily removable spacer
Leakage
Class:
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Teflon seal ring assembly is consistent with class V (IEC 60534-4) for sizes up to 20”.
For higher dimensions IVS1 class or better depending on actuator
For metal SS type IVS1 class is allowed for all sizes
Actuators:
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Valvitalia DRA pneumatic diaphragm actuator for valve sizes up to 16”
Valvitalia PRA piston types actuators with low friction scotch-yoke mechanism for higher valve sizes
Pneumatic rack and pinion both single and double acting for sizes up 24” included
Electric and hydraulic actuators available on request
VALVITALIA reserves the right to change design, specification and materials without notice
14
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Cavitation and noise control
Multi windows wings
These special trim executions are machined, depending on wings
size, from a solid cast or forged block. The design of K-LO disc is very
effective against potential cavitating conditions due to its high xFZ
values, which are close to 0,4 at 70° opening approximately for all the
dimensions. This allows to avoid cavitation under critical conditions, such
as, for example: p1 = 15 bar, p2 = 10 bar and max vapour pressure = 2,5
bar (water at 125°C). Flow coefficients are slightly affected by the
anti-cavitation large windows of the wings, while allowed disc opening
is limited to the region where recovery factor is higher.
Drilled wings
Special drilled wings allow K-LO control valve to reduce noise. This
peculiar trim pattern combines high efficiency in reducing noise with an
excellent modulating performance.
Low-noise disc design
Anti-cavitation disc design
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VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
CB54 – CB55 Ball Control Valves
Control Ball Valves of CB series provide an excellent tightness, typical of on-off ball valves with a high rangeability. CB series valves match together the ability to transfer large
flows with a precise regulating action at small flows. In this way it is possible to reach
reangeability of 200:1 and with particular trims until 300:1. Furthermore the special trim
design of CB series provides noise and cavitation abatement.
CB series are available in two configurations:
1. CB 54 has a downstream drilled disc especially engineered to reduce aerodynamic noise
2. CB 55 special multi-path / multi-stage trim allows an excellent flow control, and it is especially designed
to reduce both noise and cavitation effects.
Technical characteristics:
Body:
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Ball:
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Shaft:
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Bearings:
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Seat:
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Actuators:
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Side entry flanged
and butt-welded design
Size: from 2” to 42”
Rating: from #150 to #2500
Face to face dimensions API 6D
Materials: carbon and stainless steel,
duplex, nickel alloys
CB 55 series with integral trim up to 4”
With removable trim for 6” and over
Soft / metal to metal seat
Flow direction:
– unidirectional: CB 54
– bidirectional: CB 55
Materials: same as body
CB54 drilled disc view
Anti blow-out design
Quick changing shaft packing
Materials: stainless steel, A564 T630,
A479 XM19
Packing: teflon or graphite ring
Radial bearings: generous sizing
of these bearings allows a smooth
rotation and a maintenance-free long life
Axial bearings: thrust due to internal
pressure is held from an antifriction washer
Spring energized, double-effect piston
construction on request
Soft / metal to metal seat
Pneumatic low friction skotch-yoke
PRA type
DRA pneumatic diaphragm type
Electric, hydraulic, electro-hydraulic
CB54 gas plant installation
Leakage
Class:
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Classes IV, IV S1 and V
according to IEC 60534-4,
Class VI is also available with soft-seat
VALVITALIA reserves the right to change design, specification and materials without notice
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CB54
CB55 sectional view
CB55
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VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
RV631 series Control Valves
RV631 control valves have their main application in boiler feedwater process,
They are expressly designed for processes that require low pressure drops when
the flow rate is high and the need to avoid cavitation when flow rate is small.
The special design of its cage, splitted in 3 steps along the travel, allows the
RV631 trim to meet these process requests. During the first travel section, in
which high pressure drops might generate cavitation phenomena, the process is
controlled by a properly designed multistep cage, which causes the fluid to pass
through six pressure reduction stages: in this way any vaporization is avoided.
The last section has a final single stage cage with large flow passages which
ensures the maximum flow rate with moderate pressure drop. Each section of
the cage, welded together to form a solid rugged unit, is separated by lips that
prevent the fluid passage between adiacent sections.
Technical characteristics:
RV631 Control Valve
Body:
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Bonnet:
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Trim:
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Cage:
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Sizes: 3”, 4”, 6”, 8”, 10”, 12”
Ratings: ANSI 150, 300, 600, 900, 1500
Flanged, BW, SW
Cast standard construction
Face-to-face dimensions as per IEC 60534-3-2
Flow direction: to open
Materials: Carbon, Cr-Mo and stainless steels
Bolted to body
Same material as body
Flow direction: to open
Packing materials: teflon or graphite seal rings
Materials: Carbon, Cr-Mo and stainless steels
Balanced and fully cage-guided plug
Unbalanced design for small ports or moderate pressure drop applications
Plug seal rings: PTFE, metal or metal and graphite
Flow characteristic: modified linear (see diagram)
Variable resistance along the travel: 6-stages for low openings,
3-stages for intermediate travel and single-stage
at full opening.
Different arrangements of stages distribution can be
performed to fulfil special applications
Seat ring:
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Quick-change and free-expanding type,
precisely coupled with the cage to ensure a perfect plug
alignment
Leakage
Class:
●
Classes IV, IV S1 and V according to IEC 60534-4
Actuators:
●
Pneumatic diaphragm or piston type
Electric and electro-hydraulic actuators
●
6-stage multistep cage detail
VALVITALIA reserves the right to change design, specification and materials without notice
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RV631 3-step cage
Last cage
section with
single-stage and
high specific CV
Intermeditate section
with 3-stage and
increased specific CV
6-stage first
anti-cavitation section
CV and XFZ vs travel
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VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
PRDV steam conditioning Control Valves
PRDV control valve is a very efficient and compact equipment for steam
conditioning either in turbine by-pass lines discharging to condenser or in
cogeration processes (see included layout). Conditioning includes pressure reduction and
integrated desuperheating devices. Pressure reduction is obtained through three stages,
except in LP applications where two stages are adequate to provide good performance
and noise limitation. The first stage is the throttling section where flow rate is adjusted
by the change of plug position inside a drilled cage. The second stage is a fixed
resistance performed by a drilled basket, which creates a backpressure on the seat in
order to reduce its velocity head and the generated noise. The third stage has a patented
cone-shaped special designed drilled ring wich contributes to noise reduction and
improves the mixing of steam with the downstream injected water. Shape and
orientation of this ring optimize the steam impact against the external surface of sprayed
water pattern, where the biggest water drops tend to reunite and to improve the
atomizing efficiency of the equipment as a whole. Desuperheating section consists of a
chamber installed downstream the third stage where some spring-assisted nozzles are
mounted. Great care is taken to avoid any risk of thermal shocks, including a
jacketing of internal surface of injection chamber which is recommended
for high pressure sytems and whenever steam inlet temperature exceeds 500°C.
PRDV Control Valve
(patented design)
Technical characteristics:
●
●
Sizes: sizes depending on service conditions
Ratings: inlet section up to ANSI 2500. Outlet section up to ANSI 900 included
Construction: from bar stock or forgings. Inlet connnection and injection chamber are
welded to main body section
Pressure seal design for inlet ratings over ANSI 900
Materials: carbon steel or Cr-Mo steels, F91 (9%Cr) depending on service conditions
Plug:
●
Unbalanced or balanced with seal rings and pilot assisted depending on service conditions
Seat Ring:
●
Welded-in by a double lip-seal joint which grants against thermal distortions
and allows an easy removal from the body
Leakage
Class:
●
●
Unbalanced and pilot assisted plug: class V (as to IEC 60534-4)
Balanced plug with seal ring: class IVS1
Actuators:
●
Double effect, spring-assisted Valvitalia LPA pneumatic
piston actuators are commonly used
Electric, electro-hydraulic and hydraulic actuators
for heavy duties control application
Body and
Bonnet:
●
●
●
●
Materials:
●
●
●
●
Trim: stellited or nitrided F6NM alloy steel
and AISI 422 (1-4935)
17-4-PH is used for inlet temperature up to 375°C
Stem: AISI 316 or XM19 depending
on service conditions
Packing: pure graphite seal rings
Pressure seal ring: low hardness AISI 316
PRDV Control Valve section
VALVITALIA reserves the right to change design, specification and materials without notice
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C O N T R O L
Sizing and noise prediction
Standard well-known sizing equations (IEC 60534-2-1)
are notapplicable to PRDV control valves as a whole
due to the fixed area devices assembled downstream
the throttling stage. For this reason, all the stages are
separately sized according to IEC equations and the
selection of the whole valve is performed for each
specific application. The accuracy of the combination of
calculated Cv is guaranteed by the Valvitalia’s deep
knowledge and large experience on this matter. The total
Cv of PRDV, including all downstream devices (fixed
resistances), is not useful for selecting the valve.
In limit flow conditions, where flow rate does not depend
on downstream pressure, the effective Cv value for
predicting the flow rate is the same of first stage.
The sizing of 2nd and 3rd stage is based on the assumption
that full pressure recovery occurs between the stages so
to allow a complete fluid reheat after the restrictions.
However, unexpected errors on fixed resistances sizing do
not affect the flow rate passing through the valve
as long as limit conditions are held on first stage.
To predict noise generated by PRDV control valves the
basic principles of IEC 605434-8-3 standard are taken into
account.
Both cone shaping of 3rd stage and the optimized
steam/water mixing do contribute to the reduction of
acoustic power transmitted downstream (IEC rw factor).
The overall PRDV noise calculation is made by a proprietary VALVITALIA method based on the most advanced
studies supported by on-line verifications.
Steam conditioning PRDV valves in a combined cycle process plant
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PRDV preheating layout – circulation type
VALVITALIA reserves the right to change design, specification and materials without notice
E N E R G Y
N E E D
SAN series desuperheating nozzles
SAN NOZZLES are variable area spring-assisted nozzles for desuperheating
service.
The closed position of the plug (51) is assured by the action of a
calibrated spring (53) loaded by a threaded nut (52) locked in position by
a pin (54). When the water pressure inside the nozzle rises, the ⌬p
between steam and water increases till the water action on the plug
exceeds the spring load and the plug starts opening.
The water starts to come out from the nozzle flowing through several
holes that, due to their special design, whirl the flow before it gets in
contact with the inside surface of the plug.
The plug perfectly atomizes the water performing a 90 degrees-shaped
conical blade.
The special plug profile on the external surface which is in contact with
steam flow improves plug stability in open position.
Spring load can be adjusted to obtain the desired opening pressure. 1,3
and 5 bar are our standard settings. Other set pressure values can be
provided for special requirements.
Materials:
SAN body materials are carbon steel or Cr-Mo steel
according to operating temperature.
INCONEL X-750 has been selected for springs to
ensure maximum stability at highest temperatures.
Injection chamber is normally manufactured with
the same pipe material.
SAN 5 nozzle
VALVITALIA reserves the right to change design, specification and materials without notice
SAN nozzle spray pattern
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C O N T R O L
SAN nozzle rear view
Spring settings for SAN nozzles
SAN series
SAN Desuperheater Mounting
Side-pipe mounting
Probe mounting
One or more SAN desuperheater can be fastened at the end on a tubular element flanged or welded to the pipe.
The spray is performed close to the pipeaxis by selecting the probe lenght.
A reference pin located on the desuperheater flange ensures the correct orientation of the nozzle inside the piping.
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VALVITALIA reserves the right to change design, specification and materials without notice
A Long Experience in Energy Equipment and one Goal:
T h e C u s t o m e r ’s s a t i s fa c t i o n .
Padova Plant.
Via Campolongo, 97 - 35020 Due Carrare (PD) - Italy
Phone: +39.049.9199611 - Fax: +39.049.9125455
E-mail: tgt_sales_cv@valvitalia.com
Web site: www.valvitalia.com
10.08 - 1000 - CVD.01
VALVITALIA S.p.A. - TGT DIVISION