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Yarway 9100 Series ARC® ValveFor Centrifugal Pump Protection
Flow ControlYarway is either a trademark or registered trademark of Tyco International Services AG or its affiliates in the United States and/or other countries. All other brand names, product names, or trademarks belong to theirrespective holders.
General DescriptionThe 9100 Series ARC® provides reliable,economical protection for centrifugalpumps against the serious damage fromoverheating and instability that can resultfrom even a few minutes of low flow. Byproviding recirculation flow to the inlet ofthe pump, the 9100 ARC® helps ensure aminimum flow for stable pump operation.
The modulating 9100 ARC® createsoperating economies in several ways.The ARC® recirculates only the flowrequired to help ensure a minimum flowthrough the pump at all times. Under fullprocess main flow demand, recirculationflow is not required. But as the processmain flow demand decreases, recirculationbecomes necessary. Unlike continuousrecirculation, the ARC® responds directlyto this need. The use of an ARC® valveeliminates the need to oversize the pumpand prime mover. Such oversizing addssignificantly to the capital cost of thepump and prime mover as well as to thecost of energy needed for operation.
An ARC® valve also saves most of thecosts of a conventional multiplecomponent flow control loop because thevalve itself is a completely self-containedsystem: it is a flow sensing orifice; acheck valve; a recirculation control valveand a pressure letdown device. As a self-contained system, it requires no instrumentsignal or power source, or any of theassociated maintenance.
Manufactured and tested in the USA, the 9100 ARC® is one of an entire family of ARC® (automatic recirculation control)valves. These valves have deliveredconsistent and reliable service for overthree decades. In the USA alone, morethan 15,000 ARC® valves have beeninstalled in power plants, refineries, and chemical plants.
A self-contained system, the 9100 Series ARC® valverequires no instrument signal or power source.
Yarway 9100 Series ARC® ValveFor Centrifugal Pump Protection
Figure 2Changing process flowControlled recirculation
The heart of the recirculation valve is amain flow sensing check valve disc,which is flow sensitive, not pressuresensitive. The disc modulates to thedemand for process flow at the sametime helping ensure a minimum flowthrough the pump. This modulatingcharacteristic results in a consistent,stable, and repeatable performanceover full pressure range.
The disc is shown in the closed positionin Figure 1. In this position there is noprocess flow and the bypass is fullyopen. This protects the pump againstplanned or accidental “dead heading”which can result from a closed down
stream pump isolation valve or processcontrol valve.
As the disc lifts (Figure 2) in response toan increase in flow to the process, thebypass element which is integral to thedisc, closes the bypass flow orificesreducing recirculation flow. Recirculationflow is controlled with disc position. Thismodulation feature assures that the totalof process flow and recirculation flowexceed the minimum flow through thepump as specified by the pumpmanufacturer.
When the disc is set at full lift position,as in Figure 3, the bypass is closed.
As process flow decreases, the reverseaction occurs and the recirculation flowagain increases. Flow enters the bypasselement at the bottom of the discassembly and is controlled bycharacterized orifices inside the discstem. Flow continues through anannulus in the bypass bushing and isdirected to the outlet of the valve.
The valve provides for single phase flow in the bypass, eliminating thepossibility of flashing or cavitation. Thisis accomplished by the valve design, and if necessary, external backpressure regulator.
Operation
Yarway 9100 Series ARC® ValveFor Centrifugal Pump Protection
The cost of the electricity consumed incontinuous recirculation cooling issignificantly higher than many peoplerealize. For example, the manufacturer of a1200 gpm pump with a discharge head of500 feet, may require 400 gpm
recirculated flow to keep it cool (Figure 4).Continuously pumping 400 gpm against a500-foot head requires 65 horsepower. Ina 10¢/kwh power cost area, total annualcost savings using an ARC® valve wouldbe $48,000 (Figure 5).
300
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100
0
1600
1500
1400
1300
1200
1100
1000
900
800
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200 400 600 800
400,000
160,000
120,000
80,000
48,00040,000
0 65 100 200 300 400 0 65 100 200 300 400
Requirements for Pump Circulation (hp)
Figure 4
Assume SP GR = 0.90
Recirculation Volume, gpm
Electric Rate 12¢/kwh
Power Required for Recirculation (hp)
Figure 5
10¢
Pump Operating Cost (8760 h/yr.) $/yr.
Discharge Head (ft. of water)
Disch
arge H
ead (psi)
Yarway 9100 Series ARC® ValveFor Centrifugal Pump Protection
Flow Conditioner 20 (600 class only) ASTM A351 Type CF8M
2
11
1012
4
35
6
789
1
18
14
13
20
16
15
C
B
A
In high pressure pumping applications thesystem often does not provide adequatepressure in the bypass line to preventcavitation or flashing. Either of theseconditions is undesirable in that it cancause damage to both valves and thepipe system or cause a reduction in flowbeyond the minimum desired, jeopardizingthe pump protection system. All PRV’s willexperience a velocity induced recoveryeffect which will limit the amount ofpressure drop a valve can take and causea reduction in flow capacity.
The requirement of back pressure is generic to all pressure reducingapplications. Pressure reduction even by multiple stage cascading such as in the 7100 Series ARC® can minimize therequirement, however no valve design willredefine a fluid’s physical properties.
This becomes especially important inmodulating systems. A fixed orifice will notprovide the proper back pressure at allflow levels. As the flow in the bypass line
is reduced, the orifice becomes lesseffective. Proper system design should beused to optimize valve pressure reductionand consider all fluid dynamic effectsdownstream of any pressure reducingdevice.
When adequate back pressure is notavailable downstream of a pressurereducing valve, vapor bubbles will form inthe zone just downstream of the valve laststage control surface. This zone is definedas the “Vena Contracta” and representsthe point of highest fluid velocity andlowest pressure. The potential for 1)damage to downstream pipingcomponents and 2) flow reduction existsfrom this point. When line pressureremains below the fluid vapor pressure,any existing bubbles will remain andexpand as piping friction further reducesline pressure. This can be defined as a“FLASHING CONDITION” and ischaracterized by a polished appearanceon affected surfaces. When the line
pressure drops below the fluid vaporpressure and then recovers, anyentrapped vapor bubbles will collapse(implode). This is defined as a“CAVITATING CONDITION” and ischaracterized by a cinder like appearanceon affected surfaces. The resolution ofeither condition is best addressed byeliminating vapor formation. This can beassured by the provision of adequate backpressure. The “Back Pressure Factor” iskey to reliable system operation and mustnot be ignored in piping designconsiderations.
As such we feel it is the obligation of aresponsible Automatic RecirculationControl Valve manufacturer to analyze thesystem needs and supply a Back PressureRegulator (BPR) when it is warranted bythe laws of fluid dynamics. For on/offsystems this could be a simple orifice, butfor modulating conditions it must be adevice like the BPR noted herein.
Yarway 9100 Series ARC® ValveFor Centrifugal Pump Protection
5 Plunger ASTM A479-431 Stainless Steel with Heat TreatmentASTM A564 Type 631 (17-7 PH) H-900
6 Spring Heat Treatment7 Spring Retainer AISI 304 Stainless Steel8 Spiral Ring AISI 3029 Flow Conditioner ASME SA747-CB7Cu-110 Retaining Ring AISI 316 Stainless Steel11 Set Screw ASTM A194 Grade 8 (18-8)12 Nameplate AISI 300 Series Stainless Steel13 Drive Screw Stainless Steel
Option: BPR is available in stainless steel configuration upon request.
Parts and MaterialsItem Part Material1 Body ASME SA1052 Seat ASTM A747-CB7Cu-1 with Heat Treatment3 Plunger Guide ASTM A276-S21800 (Nitronic 60 Bar)4 O-ring TFE/P (Fluoraz 799)
5 Plunger AISI 431 Stainless Steel with Heat Treatment
6 Spring Retainer AISI 304 Stainless Steel
7 Spring ASTM A564 Type 631 (17-7 PH) H-900 Heat Treatment
Energized 8 “U” Cup Seal Filled TFE
9 Retaining Ring AISI 304 Stainless Steel10 Nameplate AISI 300 Series Stainless Steel11 Drive Screw Stainless Steel12 Spacer A269-30413 Spiral Ring Inconel® X-750
Yarway 9100 Series ARC® ValveFor Centrifugal Pump Protection
Performance – Profiled in Yarway’s Hydraulic Performance Test LabIn our hydraulic performance test laboratory, state-of-the-art data acquisition and computer graphics techniques are called upon for evaluation of the significant performancecharacteristics of Yarway recirculation control valves. The lab’s equipment makes it possible to test a valve over its complete flow range for factors including:
• Total flow through the pump
• Disc position
• Pressure drop across the main check
• Bypass Cv• Bypass DP
• Bypass leakage Cv• Valve response to sudden changes in flow
These detailed analyses are the user’s complete assurance that the valve meetsperformance requirements in all respects and can be supplied with the valve.
A certified test curve is shipped with each valve (see page 11 for example).
Insist on it, as you would for your pump!
Hydraulic Performance Test Lab
Yarway 9100 Series ARC® ValveFor Centrifugal Pump Protection
Tyco Flow Control (TFC) provides the information herein in good faith but makes no representation as to its comprehensiveness or accuracy. This data sheet is intended only as a guide to TFC products and services. Individuals using this data sheet must exercise their independent judgment in evaluating product selection and determining product appropriateness for their particular purpose and system requirements. TFC MAKES NO REPRESENTATIONS OR WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE WITH RESPECT TO THE INFORMATION SET FORTH HEREIN OR THE PRODUCT(S) TO WHICH THE INFORMATION REFERS. ACCORDINGLY, TFC WILL NOT BE RESPONSIBLE FOR DAMAGES (OF ANY KIND OR NATURE, INCLUDING INCIDENTAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES) RESULTING FROM THE USE OF OR RELIANCE UPON THIS INFORMATION. Patents and Patents Pending in the U.S.and foreign countries. Tyco reserves the right to change product designs and specifications without notice. All registered trademarks are the property of their respective owners. Printed in the USA.
www.tycoflowcontrol.com
How to Order
Our sales representatives will help you select the correct valve for your application.Please complete this form before contacting the sales office to help ensure all necessary information is provided.
Comments:
NACE Materials Required?
Flow Test with Performance Certificate Required?
Customer Inspection Required Prior to Shipment?
Certificate of Compliance for Hydro Test Required?
Magnetic Particle Test Required?
Radiograph Inspection Required (specify scope)?
Certified Material Test Report (Pressure Containing Components only)?
Orientation of ARC Valve:
Desired End Connections:
Desired Pressure Class:
Desired Body Material:
Desired Seal Material (except 2" to 8" 9200 and 9300):
Pump Drive Type:
Ethylene Propylene (EPR or EPDM)
150 300 600 900 1500 2500
Vertical Horizontal
Raised Face Flange
Flat Face Flange Ring Type Joint (RTJ)
Butt Weld EndsOther - Specify in “Comments”
A216 Gr. WCB A351 Gr. CF8MA351 Gr. CK3MCuN (6Mo)
TFE Propylene (Aflas or Fluoraz)Fluorocarbon Rubber (Viton®)Other - Specify in “Comments”
Constant Speed - Motor DrivenVariable Speed (VFD) - Motor DrivenVariable Speed - Turbine DrivenOther - Specify in “Comments”
A995 Gr. CD3MWCuN (Super Duplex)
Liquid: Boiler Feed Water (In this case disregard S.G. and V.P.)
Automatic Recirculating Control (ARC®) Valve Data Sheet
Flow tests are generally conducted on all model 5300 and 7100 ARC® valves and one model 9100 or 9200 ARC® valve per sales order line item at no additional cost.Model 9300 ARC® valves and other flow test requirements are upon request and at additional cost. If flange drilling is other than ANSI, please specify in “Comments.”Please include Pump Curve if available.