MEMORY SEAL BALL VALVES MAINTENANCE MANUAL 2 12, Class 150 & 300, Regular Port, Flanged Unibody

Transcription

1 MEMORY SEAL BALL VALVES MAINTENANCE MANUAL 2 12, Class 150 & 300, Regular Port, Flanged Unibody I INTRODUCTION These rugged, versatile, high performance, regular port, ball valves meet all requirements for oil and gas pipeline service. The valves can withstand a large variety of fluids and almost any corrosive service in chemical, oil, petrochemical, gas, pulp, paper processing and other industries. See catalog VEL-UB-2000 for pressuretemperature ratings. The valves comply with ASME/ANSI B16.34 (face-to-face, flange details), BS 5351 (minimum port size, wall thickness and markings), ISO 5211 (actuator mounting), API 598 (inspection and testing) and TA-LUFT (emission). In terms of fire safety, the unibody ball valve line meets or exceeds the minimum requirements specified in the following standards: API 607 3rd & 4th editions and BS 6755 part 2. As a result, Velan ball valves are ideally suited for applications in LP gas, petroleum and petrochemical processing. II PREPARATION Process requirements should be evaluated against valve performance characteristics and component materials before installation to assure that the valve is well suited for the intended service. Valve components (specifically seats and seals) must remain inert when placed in contact with the pipeline fluid. The pressure and temperature of the fluid in the pipeline must not exceed the maximum pressure at any given operating temperature as defined in the catalogue (VEL-UB-2000). The seat material and pressure rating are indicated on a tag fastened to the valve. Contact Velan Technical Support with any questions or concerns. These ball valves are designed for bi-directional flow unless there is an arrow on the body indicating a specific direction (in this case, the ball is drilled for cavity relief). 1 Maintenance Manuals

2 III WARNINGS & PRECAUTIONS V DISASSEMBLY For safety reasons, it is important to take the following precautions before servicing any valve: IV Personnel servicing or adjusting any valve must wear appropriate apparel and safety equipment. The pipeline and valve must be de-pressurized and bled before service can begin. The segment of the pipeline where the valve to be serviced resides should be isolated by closing all adjacent valves. Any fluid remaining in the isolated portion of the line should be removed using standard bleeding procedure. In order to relieve any pressure in the ball cavity, the valve of interest should be cycled (open to close to open) and then adjusted so that it is approximately half-open. GENERAL MAINTENANCE The Velan Unibody Ball Valve has been designed for minimal routine maintenance. In general, the following preventive maintenance should be performed: The packing is live loaded (using two Belleville washers), so frequent adjustment of the packing bolts is not necessary. However, the four packing flange bolts will occasionally have to be tightened to prevent or eliminate leakage in the vicinity of the stem. Ideally, the system pressure should be relieved before attempting to adjust these bolts. Caution should be used, however, when adjusting the packing flange bolts in order to prevent over-tightening. If excessive torque is used when tightening these bolts, the valve will become difficult to cycle and damage to the packing may result. See Table 1 below for recommended packing bolt torque values. TABLE 1: Required Packing Flange Bolt Torque Valve size Bolt Torque Bolt Torque (inches) (lbf in) (Nm) Periodically, the valve should be visually inspected to ensure that it is functioning properly. Frequent observation is suggested when the valve is subjected to severe operating conditions. Read and follow the instructions in the maintenance manual. For reference during reassembly, use a digital camera to take pictures of the valve at various stages of the disassembly process. Lay out the parts on a clean, flat surface in the order that they are removed so that the valve, when fully disassembled, resembles the exploded view in Figure 3. Do not scratch, nick or gouge any sealing surfaces. NOTES: a) Velan recommends that all seats and seals be replaced each time the valve is disassembled and reassembled. b) A special tool is required to disassemble the seat retainer (item 71 in figure 3). The tool should be fabricated, according to the instructions below based on the valve size, before the valve is removed from the line. 2" Valve A hexagon bar (1.70" maximum across parallel flats) and an adjustable wrench can be used to remove the seat retainer from 2" valves. 3"-12" Valves A symmetric, cross-shaped tool with a welded nut (for torque application) is required to remove the seat retainer from 3" to 12" valves. See Table 2 and Figure 1 for pertinent seat retainer pocket dimensions (dimensions shown are actual pocket dimensions; clearance must be added between the tool and the seat retainer cavity to ease insertion). TABLE 2: Dimension for Seat Retainer Tool Cavity Valve size Dimension A Dimension B (inches) (inches) (inches) R R R R R R.50 2

3 DISASSEMBLY V A A R B point up while the continuous raised face should be placed on a clean, soft, flat surface to ensure that it is not scratched, nicked or gouged while the valve is being serviced. See Figure 2 below for proper valve orientation. Secure the valve to the work surface so that it will not rotate. SEAT RETAINER SECTION A-A A FIGURE 1: Seat Retainer Tool Cavities DISASSEMBLY PROCEDURE: D1. Review the Warnings and Precautions portion (Section III) of this manual. D2. Remove the valve from the pipeline. Adjust the handle lever or gear operator until the valve is in the fully closed position. D3. If the valve is fitted with a handle: Remove the handle bolt (item 56 in Figure 3) and handle washer (item 57) Remove the handle (item 33 in Figure 3) from the stem or If the valve is fitted with a gear operator or an actuator: Remove the gear operator or actuator from the bracket (typically four bolts) Remove the gear operator or actuator mounting bracket (typically four bolts) Remove the driver from the stem Remove the key(s) from the stem D4. Remove the four packing flange bolts (item 17A in Figure 3) and the packing flange (item 11). D5. Remove the gland bushing (item 12 in Figure 3). D6. Pry out and discard the gland bushing sleeve (item 18 in Figure 3, an off-white, Teflon, thin walled tube) from the gland bushing. D7. Remove and discard the two O-ring seals (items 74A and 74B in Figure 3) from the gland bushing (item 12). D8. Orient the valve so that the waterway axis is perpendicular to the work surface. The raised face that includes the seat retainer should WORK SURFACE NOTE: HANDLE PARTS OMITTED FOR CLARITY FIGURE 2: Valve Orientation for Disassembly D9. Use a pen, marker or other instrument (do not use anything that will permanently scratch the face) to make a continuous, radial line from seat retainer (item 71 in Figure 3) portion of the raised face to the body (item 1) portion of the raised face. This line will be used during re-assembly to guarantee that the seat retainer face and body face are coplanar. D10. Using the seat retainer removal tool, described under Note b (page 2) and fabricated before the valve is removed from the pipeline, unscrew (counterclockwise) and remove the seat retainer (item 71 in Figure 3) from the body (item 1). D11. Remove and discard the body seal (item 19 in Figure 3, off-white, large diameter, thin Teflon piece) that resides on the cylindrical area of the seat retainer (item 71). D12. Carefully remove the ball (item 5A in Figure 3) and place it on a clean, flat, soft surface. Orient the ball so that it will not roll off the work surface. When handling the ball, use special care to avoid damaging the polished outer surface. If this surface becomes scratched, nicked or gouged, valve performance will be adversely affected. 3

4 V DISASSEMBLY A 11 74A 12 74B 18 13A 63A 36 13B 63B 17B A PARTS DESCRIPTION QTY 01 - Body Stem 1 05A - Ball 1 05B SS grounding ball (not shown) Thrust washer Stem bushing Seats Packing flange Gland bushing 1 13A - Packing ring (graphite) 1 13B - Packing rings (PTFE) 1 set of 3 17A - Packing flange socket head cap screws 4 17B - Handle stop socket head cap screws Gland bushing sleave Body gasket Handle Belleville washers SS grounding spring (not shown) Hex head bolt Flat washer 1 63A - Large diameter packing washers 2 63B - Small diameter packing washer Seat retainer sleeve 1 74A - Dynamic (small dia.) O-ring 1 74B - Static (large dia.) O-ring 1 FIGURE 3: Exploded View D13. Remove and discard both seats (item 9 in Figure 3). One seat resides within the body while the other can be found in the seat retainer. D14. Remove the stem (item 4 in Figure 3) by pushing it into the body. A soft rubber mallet can be used to facilitate removal of the stem. It is important to use caution when removing the stem. Damage to the stem (scratches, nicks or gouges) in the sealing area will adversely affect packing performance. D15. Remove the upper packing washer (item 63A in Figure 3), the graphite packing ring (item 13A) and the lower packing washer (item 63A). It is important to use caution when removing these components. Damage to the body (scratches, nicks or gouges) in the sealing area will adversely affect packing performance. Discard the graphite packing ring. D16. Remove the Belleville washers (item 36 in Figure 3, quantity 2), the upper packing washer (item 63B), the Teflon packing rings (item 13B, quantity 3) and the lower packing washer (item 63B). Again, it is important to use caution when removing these components. Damage to the body (scratches, nicks or gouges) in the sealing area will adversely affect packing performance. Discard the Teflon packing rings. D17. Apply a force, through the packing chamber, to the top surface of the stem bushing (item 7 in Figure 3) until it breaks free from the body (item 1). Remove the stem bushing and thrust washer (item 6, off-white, Teflon washer) from the waterway and discard these parts. The thrust washer may remain on the stem shaft when the stem is removed from the body in step D14. D18. Inspect the body to verify that all components (especially the stem bushing and the thrust washer) have been removed from the waterway. 4

5 Read and follow the instructions in the maintenance manual. Inspect all sealing surfaces before reassembly. Order, stock and carry extra seal kits. Order, stock and carry extra O-rings. These O-rings are commercially available in a wide range of materials. Typically, valves are configured at the factory with O-rings made from Vitron. See the table below for specific O-ring dimensions listed by valve size. TABLE 3A: Dynamic (small diameter) O-ring Dimensions Listed by Valve size Valve Cross-sectional Inner Diameter Size Diameter (inches) (inches) 2 & & TABLE 3B: Static (large diameter) O-ring Dimensions Listed by Valve size Valve Cross-sectional Inner Diameter Size Diameter (inches) (inches) 2 & & Use a commercially available O-ring lubricant on all exposed O-ring surfaces. Before assembling any threaded component, lubricate the external thread surface with a thin coat of Never Seez or an equivalent, nickel-graphite based (copper-free), commercially available thread lubricant. When a torque value is indicated, use a torque wrench to tighten the component to the specified value. Do not interchange parts from different valve assemblies (especially handles and seat retainers). TABLE 4: The Seal Kit Parts List ASSEMBLY VI Part Item No. in Fig. 3 Qty. Thrust Washer 6 1 Stem Bushing 7 1 Seat 9 2 Packing Ring (Graphite) 13A 1 Packing Ring (PTFE) 13B 3 Gland Bushing Sleeve 18 1 Body Gasket 19 1 Small Diameter O-Ring 74A 1 Large Diameter O-Ring 74B 1 ASSEMBLY PROCEDURE: A1. Using a solvent that is compatible with both the process and the valve parts, clean all components and body sealing surfaces before assembly. Visually inspect all parts and replace any components that appear worn or damaged. A2. Orient the valve so that the waterway axis is perpendicular to the work surface. The portion of the body where the seat retainer is inserted should point up while the continuous raised face should be placed on a clean, soft, flat surface to ensure that it is not scratched, nicked or gouged while the valve is being serviced. See Figure 2 above for proper valve orientation. Secure the valve to the work surface so that it will not rotate. A3. Install a new seat (item 9 in Figure 3) from the Velan Seal Kit into the body (item 1). The seat has a small diameter (inside and outside) area and a large diameter (inside and outside) area. The small diameter area should face down as the seat is inserted in the body. See Figure 4 below. If the seat does not slide easily into the pocket in the body, use a rubber mallet, a metal bar and an old seat to tap the new seat into position. The old seat should be placed on top of the new seat to prevent any damage caused by the hammering operation. When the seat is located in its final assembled position, there should not be any gap between the inside diameter of the seat and the corresponding pocket in the body. SEAT PARTIAL VIEW OF THE BODY FIGURE 4: Seat Installation in Body 5

6 VI ASSEMBLY A4. Slide a new thrust washer (item 6 in Figure 3) and a new stem bushing (item 7) down the stem (item 4) shaft until the thrust washer bottoms out on the stem shoulder. A5. Install the stem subassembly in the body (item 1 in Figure 3). A6. From the inside of the body (item 1 in Figure 3), tap the stem (item 4) lightly with a plastic hammer or rubber mallet to ensure contact between the stem shoulder, the thrust washer (item 6) and the body. A7. In order to facilitate insertion of the ball (item 5A in Figure 3), the stem (item 4) must be properly aligned. If the stem has a double "D" configuration: Orient the double "D" flats so that they are perpendicular to the waterway centerline. See Figure 5 below. or If the stem has machined keyways: Orient the machined "V"-groove on the top surface of the stem so that it is perpendicular to the waterway centerline. See Figure 6 above. A8. Carefully insert the ball (item 5A in Figure 3) into the body (item 1) with the stem slot oriented so that it will interface with the stem. The ball should be assembled in the closed position. A slight rotational motion will help ease the ball into its assembled location. See Figure 7 below. TRANSLATE & ROTATE BALL INTO ASSEMBLY POSITION STEM CUTOUT STEM FLATS FIGURE 7: Ball Installation WATERWAY CENTERLINE FIGURE 5: Stem Double D Orientation LARGE DIAMETER WASHER FLANGE GLAND BUSHING GRAPHITE RING V GROOVE WATERWAY CENTERLINE FIGURE 6: Keyed Stem Orientation SMALL DIAMETER WASHER TEFLON RING FIGURE 8: Packing Arrangement BELLEVILLE WASHERS NOTE: For Steps A9 through A18, refer to Figure 8 above. 6

7 ASSEMBLY VI A9. Install the smaller diameter packing washer (item 63B in Figure 3) over the stem (item 4) and into the packing chamber. A10. Install new Teflon packing rings (item 13B in Figure 3) over the stem (item 4) and into the packing chamber. The packing arrangement should resemble Figure 9 below. A18. Carefully slide the gland bushing subassembly (items 12, 18 and 74 in figure 3) over the stem (item 4) and into the packing area. A19.Install the packing flange (item 11 in Figure 3) over the stem (item 4). The contoured surface on the packing flange should mate with the contoured top surface of the gland bushing (item 12). Four counterbored holes should be visible when the packing flanged is assembled properly. See Figure 11 below. FIGURE 9: Teflon Packing Arrangement A11. Install the second, small diameter packing washer (item 63B in Figure 3) over the stem (item 4) and into the packing chamber. A12. Install the Belleville (cupped) washers (item 36 in Figure 3), arranged as shown in Figure 10 below, over the stem (item 4) and into the packing chamber. FIGURE 10: Belleville Washer Configuration A13. Install the large diameter packing washer (item 63A in Figure 3) over the stem (item 4) and into the packing chamber. A14. Lubricate the internal and external surfaces of the graphite packing ring (item 13A in Figure 3, charcoal colored) with Molly-Koat GNSpray or an equivalent molybdenum-disulfide based commercial lubricant. Install the graphite packing ring over the stem (item 4) and into the packing chamber. A15. Install the second large diameter packing washer (item 63A in Figure 3) over the stem (item 4) and into the packing chamber. A16.Push a new gland bushing sleeve (item 18 in Figure 3, an off-white, Teflon, thin walled tube) into the gland bushing (item 12). A17. Install a new large diameter O-ring (item 74B in Figure 3) in the external machined groove of the gland bushing (item 12). Install a new small diameter O-ring (item 74A) in the internal machined groove of the gland bushing (item 12). Select a commercially available O-ring lubricant that is compatible with the O-ring material and apply it to the exposed surfaces of both O-rings. MATING CONTOURED SURFACES FIGURE 11: Packing Flange-Gland Relative Orientation A20. Lubricate the threads of the packing flange bolts (item 17A in Figure 3) with Never-Seez or an equivalent, nickel-graphite based (copper free), commercially available thread lubricant and insert these bolts through the packing flange (item 11) into the body (item 1). Using the values given in Table 1, gradually tighten the flange bolts, with a torque wrench, following the sequence indicated in Figure 12 below. Bolt 1 should betightened to a certain torque value below that suggested in Table 1. Then, bolt 2, bolt 3 and bolt 4 should be tightened to the same torque value as bolt 1. Following the sequence shown in the Figure 12 below, repeat until all bolts are gradually tightened to the torque values listed in Table FIGURE 12: Packing Flange Bolt Sequence 7

8 VI ASSEMBLY A21.Install a new seat (item 9 in Figure 3) in the machined pocket of the seat retainer (item 71). See Figure 13 below for proper seat orientation. FIGURE 13: Seat Installation in Seat Retainer A22.Install a new body seal (item 19 in Figure 3) over the external cylindrical surface of the seat retainer (item 71). A23. Lubricate the external threads of the seat retainer with Never-Seez or an equivalent, nickel-graphite based (copper free), commercially available thread lubricant and insert the seat retainer (item 71 in Figure 3) into the body (item 1). Using the tool fabricated previously and described in the Disassembly Section of this manual under Note b, tighten the seat retainer until the body face and seat retainer face are coplanar. The mark across the raised face created in Disassembly Step D9 must line up to assure metal-to-metal contact between the body and the seat retainer (metal to metal contact is required to guarantee that the valve will perform adequately during a fire). The torque required to restore the seat retainer to its original position is approximated, according to valve size, in Table 5. TABLE 5: Approximate Seat Retainer Torque Valve size (inches) Torque (lbf ft) Torque (Nm) A24.If the valve is fitted with a handle: Install the handle (item 33 in Figure 3) on the stem (item 4). or If the valve is fitted with a gear operator or an actuator: Assemble the key(s) into the machined keyway(s) of the stem (item 4 in Figure 3). Install the driver on the stem (item 4 in Figure 3). A25.In order to assure that the ball is positioned properly between the seats, cycle the valve (close to open to close) twice before continuing (for valves fitted with a gear operator or an actuator, use an adjustable wrench across parallel flats of the driver and a long lever pipe). A26. Using a torque wrench, verify that the valve has been reassembled properly by measuring the torque required to turn the stem. The torque should be at least 25% of the maximum torque specified in the Velan Unibody Catalogue (VEL-UB-2000), but not greater that the maximum torque specified in the catalogue. A27.If the valve is fitted with a handle: Assemble the handle washer (item 57 in Figure 3) and handle bolt (item 56). or If the valve is fitted with a gear operator or an actuator: Attach the gear operator or actuator mounting bracket to the body (item 1 in Figure 3, typically four bolts required for attachment). Attach the gear operator or actuator to the bracket (typically four bolts required for attachment). A28. Reinstall the valve in the pipeline. VELAN, INC 7007 Côte de Liesse Montreal, Quebec Canada H4T 1G2 VELAN VALVE CORPORATION 94 Avenue C Williston, Vermont USA Tel: (514) Fax: (514) PRINTED IN CANADA 8 VEL-BVUB4-2001