control+valves general+catalogue valvitalia

A Long Experience in Energy Equipment and one Goal:

The Cus tomer ’s sa t i s fac t ion .

2VALVITALIA reserves the right to change design, specification and materials without notice

E N E R G Y N E E

VALVITALIA reserves the right to change design, specification and materials without notice3

CONTENTS

Globe Control Valves

LTG1 4LTG2 4LTG3 6LTG4 8LTG5 9RV631 18

Tree-way Control Valves

TRV1 10TRV2 10

Rotary Control Valves

DYNA-LOK 12K-LO 14CB-54 16CB-55 16

Steam Conditioning Control Valves

PRDV 20SAN nozzles 22

D S C O N T R O L

LTG1 and LTG2 Control ValvesGlobe straight-way, single seat LTG1 and LTG2 series are very versatile control valves ofgeneral 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-changeversion 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 andslightly abrasive fluids. Angle-body LTA special design is also available with the sametrims of LTG series.

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Main advantages:

Technical characteristics:

Body:

Bonnet:

● 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

● 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

Packing: ● Adjustable by nuts and follower● Seal rings: reinforced braided teflon or pure graphite split-rings● Bellows seal

Rangeability: ● Cvmax/Cvmin better than 50:1 for 1" port and over

Cage (LTG2 only): ● 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

Trim: ● 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

VALVITALIA reserves the right to change design, specification and materials without notice

LTG2 ANSI 300Diaphgram Actuator

E N E R G Y N E E

5 VALVITALIA reserves the right to change design, specification and materials without notice

Leakage Class(IEC 60534-4) :

● Standard: class IV● Optional: class V and VI

Actuators: ● Pneumatic diaphragm or Piston type● Electric and Electro-Hydraulic actuators

LTG1 ANSI 600Electric Actuator

LTA Control Valve

Seat Ring: ● Threaded in LTG1 model and clamped-in in LTG2 model

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 available2 - Inlet and outlet ratings can also be different3 - Centre-to-face dimensions consistent with IEC standard when the connections have

the same dimensions4 - Increased Cv values in comparison with LTG1 and LTG2 standard body style due to

less pressure drop of angle path5 - Trims, characteristics, material and actuators are the same of standard LTG series

Standard contoured plug BRD trim Soft seated plug

LTG1 Std contoured plug LTG2 Std contoured plug

D S C O N T R O L

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LTG3 Cage Control ValvesGlobe 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 parti-cularly suitable for heavy duties and for any other application under most demandingservice conditions. Due to their simple construction, to the large range of trim types andavailable materials, these valves are suitable for a wide range of applications, includingalso high temperature and corrosive fluids, severe low-noise requirements and sourservice in accordance with NACE standard.

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.

Main advantages: ● 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

LTA design


Body:

Bonnet:

● 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

LTG3 20” ANSI 900

LTG3 balanced plug


Trim: ● 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

Cage: ● 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

E N E R G Y N E E


Leakage Class: ● Classes III, IV, IV S1 and V according to IEC 60534-4Class VI is also available with soft-seat

Actuators: ● Pneumatic diaphragm or Piston type● Electric and Electro-Hydraulic actuators

Seat Ring: ● Quick-change and free-expanding type, precisely coupled to the cage to ensure a perfect plug alignment

Low noise cage construction LTG3 - cage assembling LTG3 - control valve under cryogenic test

Single stageLow noise cage

MPS trimbalanced plug

Double stagebalanced plugLTG3 plug with soft insert Linear characterized LTG3 cages MPS multistage trim

D S C O N T R O L

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LTG4 Series Control ValvesGlobe straight-way LTG4 Series Control Valves have the same body, bonnet and seat ringof LTG3 series. The main difference is the design of the plug which is balanced type andcontoured 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 bene-fits of plug balancing and quick-change feature of LTG3 series with the simple and versati-le construction of contoured plug which allows a wide selection of materials, coatings andflow characteristics. Also dirty, abrasive and very corrosive fluids can be successfully handled without the inconvenient sometime occurring in conventional throttling cage val-ves. The limitations about low-noise and anticavitation characteristics are compensated bythe free-passage shape of the plug with reduced risk of local erosionand clogging.


Body:

Bonnet:

● 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

● Quick-change and free-expanding type, precisely coupled with the cage to ensure a perfect plug alignment

LTG4 10” ANSI 2500


Trim: ● 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:

Leakage Class:

● Classes III, IV, IV S1 and V according to IEC 60534-4Class VI is also available with soft-seat plug

Actuators: ● Piston or pneumatic diaphragm spring return● Electric actuators on request

Cascade trimRepresents one of the most valid systems to reduce ero-sion and cavitation and it finds wide applications insmall size valves, whether other “multistep” solutionscan not be used. The pressure drop is equally splittedthrough a lot of labyrinth paths specially machined insi-de the trim itself. Control valves equipped with “casca-de trim” can operate under very high pressure dropswith a longer working life compared to standard singlestage trims. Two separate sealing surfaces can be provi-ded: by this way the first seal, between seat and cage,acts as a sacrifice element. LTG4 - cascade trim

E N E R G Y N E E


LTG5 Series Control ValvesLTG5 Series top guided control valves are specially designed for the control of particularfluids where dead zones inside the valve body are not tolerated due to risk of crystalliza-tion, 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 wherestagnation of fluid could cause stem corrosion, wear and leaks. Cv and other sizing factorsare the same of LTG1 series. Typical applications of these valves are:

Main features:

Body:

Bonnet:

● 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

● Food industry and drinking water● Pharmaceutical processes● Urea, melamine and similar plants

1 - No dead zones inside the body with reduced contamination and erosion2 - 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

● Inox, hastelloy, duplex, HVD1, other alloys and coatings on request and when necessary

LTG5 high pressurelug body type

for urea service

Trim: ● 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:

LeakageClass:

● Std IV – optional V or VI

Actuators: ● Pneumatic diaphragm or piston types● Electric and electro-hydraulic on request


D S C O N T R O L

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TRV1 and TRV2 3-way Control ValvesTRV control valves series are especially designed for heat exchangers control where the flow rate of the heatingfluid 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 theexchanger. In the layout of Fig.1 the valve is the diverting type TRV1 with one inlet and two outlets while in thearrangement of Fig 2 the valve is the mixing type TRV2 with two inlets from heat exchanger and by-pass. The useof 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.).

In both designs the fluid tends to open the plug to ensure the max stability to the valve operation. The selectionbetween the two solutions is basedprincipally on fluid temperature and on the differential temperature T1-T2 acrossthe 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 anddue to easier maintenance.

TRV Design

Body:

Bonnet:

● 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 orlow temperature applications as a standard feature

● Bolted to body● Same materials as body


Trim: ● Intrinsically balanced in heat exhanger application● Plug is available in two design: standard and low-noise

Fig.1 – DIVERTING TYPE 3-way controlvalve in heat exchanger application

Fig.2 – Mixing type 3-way controlvalve in heat exchanger application


TRV2 Control Valve12” ANSI 600 (mixing type)

E N E R G Y N E E


D S C O N T R O L

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DYNA-LOK rotary Control ValvesDYNA-LOK rotary control valves are provided with a double eccentric disc and a veryeasy-to-be changed TFE based or metal seat ring. Thanks to DYNA-LOK disc off-setdesign, the torque tending to close the valve and, more in general the torque neededto control the disc rotation is sensitively reduced. In addition, the cam effect performedby second shaft eccentricity guarantees a seal ring longer life. These valves can offer agreat flow control with an excellent shut-off withstanding also very high pressure drops,independently of the flow direction.


Body:

Disc:

● Sizes: wafer and lug body design: from DN 150 up to DN 2000flanged 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 sizesFor water mains DYNA-LOK control valves can be supplied in accordance with AWWAstd 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

● Two designs are available to fulfil different temperature conditions:– spring-energized Teflon ring for temperatures up to 200°C– SS ring for higher temperaturesBoth seal rings are locked inside the body by means of an easily removable spacer.


Shaft: ● 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

Bearings: ● 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

Seat Ring:

Leakage Class:

● Teflon seal ring assembly is consistent with class V (IEC 60534-4) for sizes up to 20”. For higher dimensions IVS1 class or betterdepending on actuator

● For metal SS type IVS1 class is allowed for all sizes

Actuators: ● 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

High pressure DYNA-LOKcontrol valve with PRA actuator

E N E R G Y N E E


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 limitsvery much this second well-known effect especially in the usual working travel rangefrom 40° to 90°.

32” DYNA-LOK control valve - lug body construction

D S C O N T R O L

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K-LO rotary control valves have been especially designed to meet the usual cavita-tion problems of processes when hot liquids and not negligible pressure drops facilitate the development of cavitation. These special valves are deriving from thedouble eccentric DYNA-LOK series by modifying the basic disc design with particularbaffles, 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-shapedand machined with many rectangular windows providing a moderate pressure dropso to not greatly affect the Cv of the valve with the plain disc. The distribution of thewindows 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 baffleddesign, max valve openings greater than the usual 90° are allowed to achieve higherCv values. As for DYNA-LOK valves, the off-set design reduces the torque tending toclose the valve. In addition, the cam effect caused by second shaft eccentricity improves the seal ring life.


Body:

Disc:

● 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


Shaft: ● 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

Bearings: ● 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 lifeallow a smooth rotation and a long maintenance-free valve life

● Axial bearings: axial thrusts are held by a couple of anti-friction washers

K-LO high-performance Rotary Control Valves

● 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

Seat Ring:

Leakage Class:

● 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: ● 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

E N E R G Y N E E


Low-noise disc design

Cavitation and noise control

Multi windows wingsThese special trim executions are machined, depending on wings size, from a solid cast or forged block. The design of K-LO disc is veryeffective against potential cavitating conditions due to its high xFZvalues, which are close to 0,4 at 70° opening approximately for all thedimensions. This allows to avoid cavitation under critical conditions, suchas, for example: p1 = 15 bar, p2 = 10 bar and max vapour pressure = 2,5bar (water at 125°C). Flow coefficients are slightly affected by the anti-cavitation large windows of the wings, while allowed disc openingis limited to the region where recovery factor is higher.

Drilled wingsSpecial drilled wings allow K-LO control valve to reduce noise. This peculiar trim pattern combines high efficiency in reducing noise with anexcellent modulating performance.

Anti-cavitation disc design

D S C O N T R O L

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Body:

Ball:

● 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


Shaft: ● Anti blow-out design● Quick changing shaft packing● Materials: stainless steel, A564 T630,

A479 XM19● Packing: teflon or graphite ring

Bearings: ● 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 pistonconstruction on request

● Soft / metal to metal seat

Seat:

Leakage Class:

● Classes IV, IV S1 and V according to IEC 60534-4, Class VI is also available with soft-seat

Actuators: ● Pneumatic low friction skotch-yokePRA type

● DRA pneumatic diaphragm type● Electric, hydraulic, electro-hydraulic

CB54 – CB55 Ball Control ValvesControl Ball Valves of CB series provide an excellent tightness, typical of on-off ball val-ves with a high rangeability. CB series valves match together the ability to transfer largeflows with a precise regulating action at small flows. In this way it is possible to reachreangeability of 200:1 and with particular trims until 300:1. Furthermore the special trimdesign 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 designedto reduce both noise and cavitation effects.

CB54 drilled disc view

CB54 gas plant installation

E N E R G Y N E E


CB55CB55 sectional view

CB54

D S C O N T R O L

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RV631 control valves have their main application in boiler feedwater process,They are expressly designed for processes that require low pressure drops whenthe 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 theRV631 trim to meet these process requests. During the first travel section, inwhich high pressure drops might generate cavitation phenomena, the process iscontrolled by a properly designed multistep cage, which causes the fluid to passthrough six pressure reduction stages: in this way any vaporization is avoided.The last section has a final single stage cage with large flow passages whichensures the maximum flow rate with moderate pressure drop. Each section ofthe cage, welded together to form a solid rugged unit, is separated by lips thatprevent the fluid passage between adiacent sections.


Body: ● 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


Bonnet: ● 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

Trim: ● 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)

RV631 series Control Valves

● 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

Cage:

Leakage Class:

● Classes IV, IV S1 and V according to IEC 60534-4

Seat ring: ● Quick-change and free-expanding type, precisely coupled with the cage to ensure a perfect plug alignment

Actuators: ● Pneumatic diaphragm or piston type● Electric and electro-hydraulic actuators

RV631 Control Valve

6-stage multistep cage detail

E N E R G Y N E E


RV631 3-step cage

Last cagesection withsingle-stage andhigh specific CV

Intermeditate sectionwith 3-stage andincreased specific CV

6-stage firstanti-cavitation section

CV and XFZ vs travel

D S C O N T R O L

20

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 andintegrated desuperheating devices. Pressure reduction is obtained through three stages,except in LP applications where two stages are adequate to provide good performanceand noise limitation. The first stage is the throttling section where flow rate is adjustedby 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 inorder 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 sprayedwater 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 achamber 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.


Body and Bonnet:

● 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

PRDV steam conditioning Control Valves

● Double effect, spring-assisted Valvitalia LPA pneumatic piston actuators are commonly used

● Electric, electro-hydraulic and hydraulic actuatorsfor heavy duties control application

Actuators:

Leakage Class:

● Unbalanced and pilot assisted plug: class V (as to IEC 60534-4)● Balanced plug with seal ring: class IVS1

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(patented design)

PRDV Control Valve section

E N E R G Y N E E


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 areseparately sized according to IEC equations and the selection of the whole valve is performed for each specific application. The accuracy of the combination ofcalculated Cv is guaranteed by the Valvitalia’s deep knowledge and large experience on this matter. The totalCv of PRDV, including all downstream devices (fixed resistances), is not useful for selecting the valve.In limit flow conditions, where flow rate does not dependon 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 assumptionthat full pressure recovery occurs between the stages soto allow a complete fluid reheat after the restrictions.However, unexpected errors on fixed resistances sizing donot affect the flow rate passing through the valveas long as limit conditions are held on first stage.To predict noise generated by PRDV control valves thebasic principles of IEC 605434-8-3 standard are taken intoaccount.Both cone shaping of 3rd stage and the optimizedsteam/water mixing do contribute to the reduction of acoustic power transmitted downstream (IEC rw factor).The overall PRDV noise calculation is made by a proprie-tary VALVITALIA method based on the most advancedstudies supported by on-line verifications.

Steam conditioning PRDV valves in a combined cycle process plant PRDV preheating layout – circulation type

D S C O N T R O L

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SAN NOZZLES are variable area spring-assisted nozzles for desuperheatingservice.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 bya pin (54). When the water pressure inside the nozzle rises, the �p between steam and water increases till the water action on the plugexceeds the spring load and the plug starts opening.The water starts to come out from the nozzle flowing through severalholes that, due to their special design, whirl the flow before it gets incontact with the inside surface of the plug. The plug perfectly atomizes the water performing a 90 degrees-shapedconical blade. The special plug profile on the external surface which is in contact withsteam flow improves plug stability in open position.Spring load can be adjusted to obtain the desired opening pressure. 1,3and 5 bar are our standard settings. Other set pressure values can be provided for special requirements.


SAN series desuperheating nozzles

SAN 5 nozzle SAN nozzle spray pattern

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.

E N E R G Y N E E


Side-pipe mounting Probe mounting

Spring settings for SAN nozzles SAN nozzle rear view

SAN series

SAN Desuperheater 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.

D S C O N T R O L

A Long Experience in Energy Equipment and one Goal:

The Cus tomer ’s sa t i s fac t ion .

VALVITALIA S.p.A. - Control Valves DivisionVia Campolongo, 97 - 35020 Due Carrare (PD) - Italy

Phone: +39.049.9199611 - Fax: +39.049.9125455E-mail: [email protected]

Web site: www.valvitalia.com

Padova Plant.

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