Data Sheet

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Bulletin 71.4:LR128

D103577X012

November 2014

www.fisherregulators.com

Type LR128 Relief Valve or

Backpressure Liquid Regulator

Figure 1. Type LR128 Relief Valve or Backpressure Regulator

Introduction

The Type LR128 pilot-operated, pressure relief valve

or backpressure regulator is designed for liquid

industrial/commercial applications. The Type LR128

provides smooth operation, tight shutoff and long

life. Its internally actuated metal plug eliminates

disadvantagesassociatedwithexibleelementstyle

regulatorsandthespeciallyengineeredowpath

deectsdebris,protectingtheseatfromdamageand

erosion. The Type LR128 is used in conjunction with a

Type MR98H pilot and Type 112 restrictor. An internal

inlet strainer prevents large particles from entering the

main valve, limiting damage to internal parts.

• Rugged design

• Reliable

• Thoroughly tested

• Internally actuated

• Compact

• 1, 2, 3 and 4 in. /

DN 25, 50, 80 and

100 body sizes

• Recommended for water

and oil applications

• Full SST construction

available for

harsh environments

• API 614 Compliant

Backpressure Liquid Regulator

Summary of content (16 pages)

PAGE 1
Bulletin 71.4:LR128 November 2014 Type LR128 Relief Valve or Backpressure Liquid Regulator • Rugged design • Reliable • Thoroughly tested • Internally actuated • Compact • 1, 2, 3 and 4 in. / DN 25, 50, 80 and 100 body sizes • Recommended for water and oil applications • Full SST construction available for harsh environments • API 614 Compliant Figure 1.
PAGE 2
Bulletin 71.4:LR128 Specifications Main Valve Body Sizes, End Connection Styles and Structural Design Ratings(1)(2) See Table 1 Maximum Inlet Pressure(1) Type LR128 Main Valve: See Table 1 Type MR98H Pilot: See Table 2 Type 112 Restrictor: 1500 psig / 103 bar Maximum Outlet Pressure Type LR128 Main Valve: See Table 1 Type MR98H Pilot: 450 psig / 31.0 bar Relief Set Pressure/Backpressure Control Ranges See Table 3 Main Valve Plug Travel 1 in. / DN 25: 0.37 in. / 9.4 mm 2 in. / DN 50: 0.
PAGE 3
Bulletin 71.4:LR128 7 TRIM PACKAGE W7398 11 3 TYPE MR98H PILOT 9 TYPE MR98H PILOT 10 1 5 6 2 TYPE LR128 RELIEF VALVE OR BACKPRESSURE REGULATOR Figure 2. Type LR128 Features and Benefits Features and Benefits 1 2 3 Tight Shutoff – The Type LR128 uses a diaphragm and metal plug, eliminating the disadvantages of fl exible element style regulators. When open, the metal plug defl ects particles and debris away from the diaphragm.
PAGE 4
Bulletin 71.4:LR128 7 8 4 12 W7345 Figure 2. Type LR128 Features and Benefits (continued) allows thorough testing of all new designs. Tests are conducted on Fisher® branded regulators for performance features such as fl ow, strength, shutoff and material compatibility. 4 and shows the actual valve position. The travel indicator makes in-service inspection and troubleshooting easy. Also, it can be used for remote alarming and monitoring stem position.
PAGE 5
Bulletin 71.4:LR128 Table 1. T ype LR128 Main Valve Body Sizes, End Connection Styles, Structural Design Ratings and Maximum Operating Relief (Inlet) Pressure(1) MAIN VALVE BODY SIZE In. MAIN VALVE BODY MATERIAL END CONNECTION STYLE(2) DN WCC Steel 1, 2, 3 and 4 STRUCTURAL DESIGN RATING(3) 25, 50, 80 and 100 CF8M Stainless steel maximum operating relief (inlet) pressure including build-up(3) Maximum Operating Outlet Pressure psig bar psig bar psig bar NPT or SWE (1 and 2 in.
PAGE 6
Bulletin 71.4:LR128 TYPE 112 RESTRICTOR TYPE MR98H PILOT PM O C MAIN SPRING DIAPHRAGM AND PLUG ASSEMBLY internal strainer M1217 inlet pressure outlet pressure atmospheric pressure loading pressure Type LR128 with Type MR98H Pilot and tYPE 112 Restrictor Figure 3.
PAGE 7
Bulletin 71.4:LR128 and plug assembly. Force from the main spring, in addition to inlet pressure bleeding through the Type 112 restrictor, provides a downward loading pressure to keep the main valve diaphragm and plug assembly tightly shutoff. When the inlet pressure rises above the set pressure, the pressure on the pilot diaphragm overcomes the pilot control spring and opens the pilot valve plug. The pilot then exhausts the loading pressure from the top of the main valve diaphragm and plug assembly.
PAGE 8
Bulletin 71.4:LR128 CAVITATION PREDICTION 375 / 26.0 335 / 23.1 OUTLET PRESSURE (P2) psig / bar 295 / 20.3 255 / 17.6 215 / 14.8 175 / 12.1 135 / 9.3 95 / 6.6 55 / 3.8 15 / 1.0 0 45 / 3.1 90 / 6.2 135 / 9.3 180 / 12.4 225 / 15.5 270 / 18.6 315 / 21.7 360 / 24.8 405 / 27.9 450 / 31.0 INLET PRESSURE (P1) psig / bar CONTINUOUS SERVICE REGION INTERMITTENT SERVICE REGION FULL CAVITATION REGION Figure 4. Cavitation Sizing for Water Table 4.
PAGE 9
Bulletin 71.4:LR128 Table 5. Type LR128 Main Valve Minimum Differential Pressure(1) MAIN VALVE BODY SIZE in. DN 1 psid bar d psid bar d 17E68 (standard) Nitrile (NBR), Low Minimum Differential 30 2.1 30 2.1 17E97 Nitrile (NBR), High Erosion Resistance 35 2.5 35 2.5 17E88 Fluorocarbon (FKM), High Temperature Capability 30 2.1 30 2.1 17E68 (standard) Nitrile (NBR), Low Minimum Differential 18 1.2 19 1.3 17E97 Nitrile (NBR), High Erosion Resistance 24 1.7 24 1.
PAGE 10
Bulletin 71.4:LR128 Table 8. Flow and Sizing Coefficients for Type MR98H Pilot WIDE-OPEN COEFFICIENT BODY SIZE 1/2 in. / DN 15 Cv Cg 3.4 120 C1 Km 35.3 0.88 IEC SIZING COEFFICIENTS XT FD FL 0.787 0.78 0.94 Km = FL2 Table 9. Type 112 Restrictor Flow Coefficients Restrictor Setting Cv Setting 2 0.03 Setting 4 0.07 Setting 6 0.14 Setting 8 0.17 C1 35 Table 10.
PAGE 11
Bulletin 71.4:LR128 Table 12. Cv(1) at % Offset (Pressure Build-Up Above Setpoint)(2) Spring Range, Part Number and Spring Color 35 to 75 psig / 2.4 to 5.2 bar 1D7455T0012 (Green) 70 to 140 psig / 4.8 to 9.7 bar 1E395727192 (Red) 130 to 200 psig / 9.0 to 13.8 bar 1L380027142 (Blue) 100 to 375 psig / 6.9 to 26.0 bar 14B9942X022 (Unpainted) BODY SIZE Set Pressure 1 in. / DN 25 2 in. / DN 50 3 in. / DN 80 4 in.
PAGE 12
Bulletin 71.4:LR128 Table 13. Capacity(1), Water (GPM / L/min) for 1 and 2 in. / DN 25 and 50 Bodies at % Offset (Pressure Build-Up Above Setpoint)(2) Spring Range, spring Part Number and Spring Color 70 to 140 psig / 4.8 to 9.7 bar 1E395727192 (Red) 130 to 200 psig / 9.0 to 13.8 bar 1L380027142 (Blue) 100 to 375 psig / 6.9 to 26.0 bar 14B9942X022 (Unpainted) 1 in. / DN 25 10% psig 35 to 75 psig / 2.4 to 5.2 bar 1D7455T0012 (Green) BODY SIZE Set Pressure 20% 2 in.
PAGE 13
Bulletin 71.4:LR128 Table 13. Capacity(1), Water (GPM / L/min) for 3 and 4 in. / DN 80 and 100 Bodies at % Offset (Pressure Build-Up Above Setpoint)(2) (continued) Spring Range, Spring Part Number and Spring Color 70 to 140 psig / 4.8 to 9.7 bar 1E395727192 (Red) 130 to 200 psig / 9.0 to 13.8 bar 1L380027142 (Blue) 100 to 375 psig / 6.9 to 26.0 bar 14B9942X022 (Unpainted) 3 in. / DN 80 10% psig 35 to 75 psig / 2.4 to 5.2 bar 1D7455T0012 (Green) BODY SIZE Set Pressure 20% 4 in.
PAGE 14
Bulletin 71.4:LR128 type MR98H Pilot M OPTIONAL INDICATOR COVER 1/4 NPT VENT travel indicator t cover removal clearance TYPE 112 RESTRICTOR 1/8 NPT CONTROL LINE connection E D 1/2 NPT PILOT EXHAUST connection D1 1/4 NPT PILOT SUPPLY connection valve trim v removal clearance G A B ERAA03112_A Figure 5. Type LR128 Dimensions Schematic Table 15. Type LR128 Dimensions Dimensions, In. / mm body size, In. / DN a cl150 rf CL300 RF 1 / 25 3.62 / 91.9 3.88 / 98.6 4.13 / 104.9 7.25 / 184.
PAGE 15
Bulletin 71.4:LR128 Ordering Information Carefully review each specification on page 2, then complete the Ordering Guide on this page. If a pilot setpoint is not requested, the regulator will be factory set at the approximate midrange. Please complete the Specification Worksheet on page 16. Ordering Guide Body Size (Select One) 1 in. / DN 25*** 2 in. / DN 50*** 3 in. / DN 80*** 4 in.
PAGE 16
Bulletin 71.