CONTROLS A Division of BRAY INTERNATIONAL, Inc.
Resilient Seated Butterfly Valves Technical Manual - Table of Contents Topic Page(s) Introduction to Torques.........................................3 Reduced Disc Diameter Bray Valves 30/31/3A...6 Seating & Unseating Torques...............................7 20/21, 30/31 Imperial (Lb-Ins)................................8 20/21, 30/31 Metric (N-m).....................................9 32/33, 35/36..........................................................
Resilient Seated Butterfly Valves – Torques Torques INTRODUCTION CASE I There are a number of torques which butterfly valves may experience such as: TT = Th + Tbf + Tss+ Tsu Tsu - Seating and Unseating Torque Td - Dynamic Torque Resulting from fluid flow Tbf – Bearing Friction Torque Tss – Stem Seal Friction Torque Te – Eccentricity Torque resulting from disc offset from centerline of stem (either single, double or triple offset) Th – Hydrostatic Torque Factors which influence the butterfly valve torqu
Resilient Seated Butterfly Valves – Torques D. Seating/Unseating Torques (Tsu) A. Bearing Friction Torque (Tbf) The seating/unseating torque value (Tsu) is a function of the pressure differential, the seat material’s coefficient of friction, the finished surface of the disc edge, the amount of interference between the seat I.D. and disc O.D. when flanged in piping, the seat thickness, and the type of service (media) for which the valve is being used.
Resilient Seated Butterfly Valves – Torques As shown in Figure 2, dynamic torque for Bray’s symmetrical disc valves is at 0° angle of opening and increases until the angle of opening reaches 75°-80°, where it then decreases to a zero value at full open (90°) (no internal friction factors considered, just dynamic torque only).
Resilient Seated Butterfly Valves – Torques Reduced Disc Diameter Bray Series 30/31/3A Valves Bray offers a reduced disc diameter for 4”-20” for Series 30, 31 and 3A valves. The purpose of reducing the disc diameter is to decrease the seating/unseating torques and extend the seat life on low pressure applications. Bray does the following to differentiate reduced diameter discs from full diameter discs: By reducing the disc diameter, the interference between the disc O.D. and seat I.D.
Resilient Seated Butterfly Valves – Seating & Unseating Torques Seating & Unseating Torques Bray has developed Seating/Unseating Torque Charts for three Classes of Service for its valves with standard discs (rated for full pressure) and for valves with reduced diameter discs (rated for 50 PSI / 3.5 bar.). Characteristics of Application Class A The guidelines for selecting a Class to be used for determining a valve’s seating/unseating torque are given below.
Resilient Seated Butterfly Valves – Seating & Unseating Torques Series 20/21 and 30/31/3A Torques (Lb-Ins) Valve Differential Pressure (PSIG) Valve Size Inches Class A Non-Corrosive, Lubricating Service Class B General Service Class C Severe Service Torque : 8 Reduced Disc Full Disc 0 psi 50 psi 100 psi 150 psi 175 psi 0 psi 50 psi 1 1.5 2 2.
Resilient Seated Butterfly Valves – Seating & Unseating Torques Series 20/21 and 30/31/3A Torques (N-m) Valve Differential Pressure (Bar) Valve Size mm Class A Non-Corrosive, Lubricating Service Class B General Service Class C Severe Service Torque : 9 Reduced Disc Full Disc 0 bar 3.4 bar 7 bar 10.3 bar 12 bar 0 bar 3.
Resilient Seated Butterfly Valves – Seating & Unseating Torques Series 32/33, 35/36 Torques (Lb-Ins) Valve Size inches Class B General Service (Imperial) Class C 24 26 28 30 32 34 36 40 42 44 48 54 60 66 72 78 84 90 96 32, 35 - Max P = 75 psi 33, 36 - Max P = 150 psi 0 psi 25 psi 50 psi 75 psi 0 psi 50 psi 6,700 7,900 9,200 10,400 11,700 13,500 14,300 18,200 20,200 20,800 22,000 41,500 55,500 115,700 8,100 9,800 11,600 13,300 15,600 18,500 20,100 26,200 29,200 32,500 39,000 73,500 98,200 159,
Resilient Seated Butterfly Valves – Seating & Unseating Torques Seating/Unseating Torques Bray Series 22/23 Valves Valve Size ∆P = 0-150 psi ∆P = 0-10.3 bar Lb-In N-m 50 288 33 2.5 65 350 40 3 80 560 63 4 100 720 81 5 125 960 108 6 150 1,300 147 8 200 2,402 271 10 250 3,840 434 12 300 5,812 657 14 350 8,000 904 16 400 11,000 1,243 18 450 15,500 1,751 20 500 19,300 2,181 24 600 30,500 3,446 In.
Resilient Seated Butterfly Valves – Torques Dynamic Torque Factors (Imperial) To Use the Torque Chart, note the following: 1. Dynamic Torque values include all bearing friction and 3. Bray recommends sizing control valves between 20° and 2. Dynamic Torque values are per 1 PSI ∆P. To determine 4. Dynamic Torque will tend to close all Bray valves whose 70°, with 60° the preferred angle. stem-seal friction torques. disc are symmetrical to the stem.
Resilient Seated Butterfly Valves – Torques Dynamic Torque Factors (Metric) To Use the Torque Chart, note the following: 1. Dynamic Torque values include all bearing friction and 3. Bray recommends sizing control valves between 20° and 2. Dynamic Torque values are per 1 Bar ∆P. To determine 4. Dynamic Torque will tend to close all Bray valves whose 70°, with 60° the preferred angle. stem-seal friction torques. disc are symmetrical to the stem.
Resilient Seated Butterfly Valves – Valve Sizing Coefficients Valve Sizing Coefficients: 1. Valve Sizing Coefficients (Cv) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pages 14-15 1. Cv stands for Valve Sizing Coefficient, sometimes called the Flow Rate Coefficient. 2. Cv varies with the valve size, angle of opening and the manufacturer’s valve style. 3.
Resilient Seated Butterfly Valves – Valve Sizing Coefficients Series 20/21 - Valve Sizing Coefficient (Cv) Valve Size inches Disc Position (Degrees) 10º 20º 30º 40º 50º 60º 70º 80º 90º 1 0.1 1 3 6 11 21 36 56 61 1.5 0.2 2 6 11 26 50 87 129 147 2 0.9 7 16 27 45 73 123 172 244 2.
Resilient Seated Butterfly Valves – Valve Sizing Coefficients Series 30/31/31H/3A/3AH/31U - Valve Sizing Coefficient (Cv) Valve Size Inches Disc Position (Degrees) 10º 20º 30º 40º 50º 60º 70º 80º 90º 2 0.8 7 16 27 43 61 84 114 144 2.
Resilient Seated Butterfly Valves – Valve Sizing Coefficients Series 20/21 - Valve Sizing Coefficient (Kv) Valve Size mm Disc Position (Degrees) 10º 20º 30º 40º 50º 60º 70º 80º 90º 25 0.087 0.865 2.595 5.190 9.515 18.165 31.140 48.440 52.765 40 0.173 1.730 5.190 9.515 22.490 43.250 75.255 111.585 127.155 50 0.779 6.055 13.840 23.355 38.925 63.145 106.395 148.780 211.060 65 0.865 9.515 21.625 37.195 61.415 99.475 173.865 268.150 379.735 80 1.730 13.840 30.
Resilient Seated Butterfly Valves – Valve Sizing Coefficients Series 30/31/31H/3A/3AH/31U - Valve Sizing Coefficient (Kv) Valve Size mm Disc Position (Degrees) 10º 20º 30º 40º 50º 60º 70º 80º 90º 50 0.692 6.055 13.840 23.355 37.195 52.765 72.660 98.610 124.560 65 0.865 9.515 20.760 37.195 57.955 92.555 140.995 192.895 243.930 80 1.730 12.975 30.275 52.765 83.040 133.210 230.955 314.860 398.765 100 2.595 23.355 53.630 94.285 147.915 237.010 429.040 606.
Resilient Seated Butterfly Valves – Flange to Valve Bolting Guide Examples of Typical Flange to Valve Bolting* ** Lug Style Bolting Valve Body Raised Face Flange Raised Face Flange Valve Body Washer Washer **Minimum Bolt Engagement Must Be Equal to Diameter of Bolt Flange Width + Including Raise Face If Applicable Necessary Minimum Bolt Engagement Equal to Bolt Diameter + Washer Width Bolt = Length ** Wafer Style Bolting Flat Face Flange Flat Face Flange Washer Flange Width x2 + Including
Resilient Seated Butterfly Valves – Flange Bolt Tensioning Data Flange Bolt Tensioning Bray Butterfly Valves with Metal Mating Flanges A question frequently asked at Bray is “What torque do I apply to the flange bolts to insure the valve is properly installed?”. Initially this seems to be a simple request until all of the factors are analyzed. The installation of a valve requires several components: the valve, mating flanges, nuts, bolts and studs.
Resilient Seated Butterfly Valves – Flange Bolt Tensioning Data 5. When all bolts are snug-tight, each bolt in the joint then shall be tightened additionally by the applicable amount of nut rotation given in Note 1. During tightening there shall be no rotation of the valve or flange. Note 1 For bolt lengths not exceeding 8 diameters or 8 inches (203.2 mm) = 1/4 turn For bolt lengths exceeding 8 diameters or 8 inches (203.
Resilient Seated Butterfly Valves – Flange Bolt Tensioning Data Series 22/23 Installation - Flange Bolt Torque Chart, 150 lb Flanges Valve Size Normal Torque Range Max Torque Range In mm Ft-lbs N-m Ft-lbs N-m 2 50 30 40 35 50 2.
Resilient Seated Butterfly Valves – Standard Metal Specifications Series 20/21 - Standard Metal Specifications Part Material Body Disc/Stem 1-12”(25-300mm) One Piece Disc Disc/Stem 14-20” (350-500mm) Fabricated Stem ASTM No. UNS No. Cast Iron A126 Class B Ductile Iron A395 Gr.
Resilient Seated Butterfly Valves – Standard Metal Specifications Series 30/31, 31H, 3A/3AH, 31U - Standard Metal Specifications Part Material Body Disc Stem ASTM No. UNS No. 30/31 31H 3A/3AH • • • • • • Cast Iron A126 Class B Ductile Iron A536 Gr. 65-45-12 F33100 Ductile Iron A395 F32800 Carbon Steel A216 WCB J030002 Nickel Aluminum Bronze B148 C95800 Aluminum B26 Class B Aluminum Bronze B148 C95400 Nickel Aluminum Bronze B148 C95800 Nylon Coated Ductile Iron A536 Gr.
Resilient Seated Butterfly Valves – Standard Metal Specifications Series 32/33, 35/36, 35F, 36H - Standard Metal Specifications Part Material Body Disc UNS No. 32-36 36H 35F • • • Cast Iron A126 Class B Ductile Iron A536 Gr. 65-45-12 F33100 Carbon Steel A216 Gr. WCB J030002 316 Stainless Steel A351 CF8M J92900 Nickel Aluminum Bronze B148 C95800 Nylon Coated Ductile Iron A536 Gr.
