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Fisherr 2625 and 2625NS Volume Boosters

A Fisher 2625 or 2625NS volume booster is used inconjunction with a positioner on a throttling controlvalve to increase stroking speed. The 2625NS is anuclearservice version and uses elastomericcomponents that better withstand high temperatureand radiation environments.

The booster incorporates fixed deadband, soft seatconstruction, and an integral bypass restriction toeliminate positioner saturation problems that canoccur with volume boosters that do not have thesefeatures. Adjustment of the integral bypass restrictionis necessary for system stability. This adjustment does

not affect the deadband of the volume booster, butdoes permit the control valve to respond to small inputsignal changes without sacrificing steadystateaccuracy. It also allows the booster to deliverhighvolume output for fast stroking when large, rapidinput signal changes occur.

The volume booster, when used in conjunction with apositioner/actuator, is used only to improve strokingspeed. It is not recommended for other applicationsrequiring a highaccuracy, instrumenttype volumebooster. If the volume booster is to be used only withan actuator, for onoff control, the integral bypassrestriction on the booster must be closed (turned fullyclockwise).

Connectors and piping can be installed with either2625 or 2625NS volume booster for diagnostictesting.

The 2625 is certified for use in Safety InstrumentedSystem (SIS) applications. Certification is by exidaConsulting LLC, a global provider of functional safetyand control system security. SIS certification isidentified on the product by a label affixed to the lowerhousing.

W4727

Featuresn Fast ResponseBooster delivers the volume needed

for rapid actuator stroking when large inputchanges suddenly occur.

n Adjustable ResponseIntegral bypass restrictiontunes the booster response so that smooth actuatormotion follows the slow signal changes.

n Efficient OperationSoft seats provide tight shutoffto reduce unnecessary air consumption andeliminate saturation of positioner relays.

n Maintains AccuracyBooster permits high actuator

stroking speeds upon demand without degradingthe positioner steadystate accuracy.

2625 and 2625NS Volume BoostersD200071X012

Product Bulletin62.3:2625

October 2012


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Product Bulletin62.3:2625October 2012

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Specifications

Supply Pressure Ranges

When used in conjunction with a positioner or other

pneumatic accessory, always pipe the positioner andvolume booster with one common supply through aFisher 64 or 95H regulator (see figure 2). Ahighcapacity filter, such as the Fisher 262C, shouldbe installed in the supply line to the regulator. Supplypressure also must not exceed the maximumpressure rating of the actuator. Constructions areavailable in two maximum supply ranges.When Normally Used With Diaphragm Actuators: Upto 2.8 bar (40 psig)When Normally Used With Piston Actuators: Up to10.3 bar (150 psig)

Input Signal Pressure

Positioner output

Maximum Input Signal Pressure

10.3 bar (150 psig)

Fixed InputtoOutput Pressure Ratio

1 to 1

Nominal Deadband

Percent of Positioner Output Span(1):2.4 mm (0.094 inch) exhaust port: 2%9.5 mm (0.375 inch) exhaust port: 3.5%12.7 mm (0.5 inch) exhaust port: 5%

Construction Materials

Body: AluminumSeat Ring: Brass

Diaphragms2625: Nitrile/nylon2625NS: EPDM/metaaramid

Upper and Lower Valves:2625: NitrileCSM rubber/aluminum/stainless steel

2625NS: EPDM/aluminum/stainless steelORings:2625N: Nitrile2625NS: EPDMConnectors for Diagnostic Testing:J Stainless steelorJ brass

Operative Temperature Limits(2)

2625: -40 to 71_C (-40 to 160_F)2625NS: -40 to 93_C (-40 to 200_F)

Connections

Input Signal: 1/4 NPTSupply and Output: 3/4 NPT

Port Diameters(3)

Supply Port:J9.5 mm (0.375 inch) orJ 12.7 mm (0.5 inch)Exhaust Port:J2.4 mm (0.094 inch),J9.5 mm (0.375 inch) orJ12.7 mm (0.5 inch)

Maximum Flow Coefficients

See table 1

Hazardous Area Classification

Complies with the requirements of ATEX Group II

Category 2 Gas and Dust

Safety Instrumented System Classification

SIL3 capable - certified by exida Consulting LLC

Approximate Weight

2.3 kg (5 lb)

NOTE: Specialized instrument terms are defined in ANSI/ISA Standard 51.1 - Process Instrument Terminology.1. Zero to maximum supply.2. The pressure/temperature limits in this document and any applicable code or standard should not be exceeded.3. May be used in any combination.


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Figure 1. Sectional View of Fisher 2625 Volume Booster

INPUT SIGNAL

BYPASS RESTRICTIONADJUSTING SCREW

BYPASSRESTRICTION

SUPPLYPORT

OUTPUT TOACTUATOR

SUPPLY

EXHAUST

EXHAUSTPORT

DIAPHRAGMS

W06791

Principle of Operation

Refer to figures 1 and 2. Because of the bypassrestriction, large input signal changes register on thebooster input diaphragm sooner than in the actuator.A large, sudden change in input signal causes apressure differential to exist between the input signaland the output of the booster. When this occurs, thediaphragms move to open either the supply port or theexhaust port, whichever action is required to reduce

the differential. The port remains open until thedifference between the booster input and outputpressures returns to within the deadband limit of thebooster. With the bypass restriction adjusted for stableoperation, a signal with small magnitude and ratechanges passes through the bypass restriction and intothe actuator without initiating booster operation.

Both supply and exhaust ports remain closed,preventing unnecessary air consumption and possiblesaturation of positioner relays.


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Figure 2. Typical Installations

2625VOLUMEBOOSTER

POSITIONEROUTPUT

SIGNAL

POSITIONER

ACTUATOR

64 OR 95H

SUPPLY

Note:1 Connection location for diagnostic testing

WITH A PISTON ACTUATOR

WITH A DIAPHRAGM ACTUATOR

A07943

E1407

SIGNAL

DIGITAL VALVE CONTROLLERACTUATOR

64 OR 95H2625VOLUMEBOOSTER

2625VOLUMEBOOSTER

SUPPLY

OUTPUT A

OUTPUT B

Table 1. Maximum Flow Coefficients(1)

PORT SIZE COMBINATIONS COEFFICIENTS

Supply Port Exhaust Port Supply Port Exhaust Port

mm Inch mm Inch Cv Cv

9.5 3/8

2.4

9.5

12.7

3/32

3/8

1/2

3.74

3.74

3.74

0.23

2.29

2.52

12.7 1/2

2.4

9.5

12.7

3/32

3/8

1/2

4.98

4.98

4.98

0.24

2.30

2.72

Fisher 3570 valve positioner 0.25 0.25

Fisher 3582 valve positioner 0.17 0.19

Fisher 3610J, 3610JP, 3611JP, 3620J, 3620JP, 3621JP valve positioners 0.37 0.30

FIELDVUEtDVC5000, DVC5000f digital valve controllers (obsolete product) 0.24 0.27

FIELDVUE DVC6200, DVC6200f, DVC6000, DVC6000 SIS, DVC6000f digital valve controllers 0.37 0.31

FIELDVUE DVC2000 Digital Valve ControllerLow Pressure RelayHigh Pressure Relay

0.150.13

0.170.18

1. Consult your Emerson Process Management sales office for special stroking speed requirements.


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Figure 3. Dimensions

A08073

3/414 NPTSUPPLY CONN

9 EXHAUSTHOLES 7 (0.28) DIA

1/418 NPT INPUT CONN

21(0.84)

111(4.38)

48(1.88)

3/414 NPTOUTPUT TO ACTUATOR

121(4.75)

60(2.38)

mm(INCH)

2625NS forNuclearServiceApplicationsThe 2625NS volume booster uses EPDM(ethylenepropylene) elastomeric parts. These parts

have superior resistance to degradation at elevatedtemperature and radiation levels. This version isdesigned for nuclear service applications where oilfree

supply air is available.

Both the 2625 and 2625NS are available assafetyrelated items when processed using thecommercial grade dedication section of the 10CFR50,Appendix B, quality assurance program. 10CFR21reporting is also part of the safety related processingprogram. Seismic operability testing has been done to

qualify both versions as rigid items at levels up to 9g'suniaxial (in each axis). Further nuclear servicequalification data is available on request.


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Installation

Figure 2 shows typical installations for the 2625 or

2625NS volume booster on piston and diaphragmactuators. A single regulator that supplies both thepositioner and booster (or boosters) is recommended.The supply medium must be clean, dry, oilfree air ornoncorrosive gas.

Note

Use a clean, dry, oilfree air supply with instrumentscontaining EPDM components. EPDM is subject todegradation when exposed to petroleumbase lubricants.

Keep in mind that many actuators require larger casingor cylinder connections to take full advantage of thebooster's ability to deliver its highvolume output.Dimensions are shown in figure 3. Ensure that thesupply pressure is connected to correspond with theflow arrow on the booster.

Ordering InformationWhen ordering, specify:

1. Supply and exhaust port sizes. See table 1 for Cvvalues.

2. Supply pressure range of up to 2.8 bar (40 psig) orup to 10.3 bar (150 psig).

3. Stroking speed information when being mounted atthe factory, for proper tuning of the instruments.Specify either critical or noncritical stroke speedtime.

Note

Critical stroke speed time example: Valve to stroke in bothdirections in 4 seconds or less.

Noncritical stroke speed time example: Valve to stroke inapproximately 4 seconds in both directions.

4. Nuclear service, if applicable. Consult factory forordering assistance.

5. SIS certification, if applicable.


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Emerson Process ManagementMarshalltown, Iowa 50158 USASorocaba, 18087 BrazilChatham, Kent ME4 4QZ UKDubai, United Arab EmiratesSingapore 128461 Singapore

www.Fisher.com

The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are notto be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. All sales aregoverned by our terms and conditions, which are available upon request. We reserve the right to modify or improve the designs or specifications of suchproducts at any time without notice.

E 1986, 2012 Fisher Controls International LLC. All rights reserved.

Fisher and FIELDVUE are marks owned by one of the companies in the Emerson Process Management business unit of Emerson Electric Co. Emerson Process

Management, Emerson, and the Emerson logo are trademarks and service marks of Emerson Electric Co. All other marks are the property of their respectiveowners.

Neither Emerson, Emerson Process Management, nor any of their affiliated entities assumes responsibility for the selection, use or maintenanceof any product. Responsibility for proper selection, use, and maintenance of any product remains solely with the purchaser and end user.

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