BW7A Butterfly Valves. Installation and Maintenance Instructions /1 IM-P CH Issue 1

Transcription

1 BW7A Butterfly Valves Installation and Maintenance Instructions /1 IM-P CH Issue 1

2 INSTALLATION AND MAINTENANCE INSTRUCTIONS CONTENTS SECTION. General 1 Additional Recommendations 1.2 Installation 2 Post Installation Proceedures 2.2 Effect of Flange Weld Types on the Butterfly Valve 2.3 Valve Inspection and Maintenance 3 Removal from Pipe work 3.2 Overhaul and Reassembly (Valve) 3.3 / 3.4 Correct Assembly of Valve (Valve) 3.5 Actuator Orientation 4 Mounting of actuators to the valve 5 Air Supply 6 Solenoid Valve 7 Actuator Maintenance 8 Component Diagrams 9 SPIRAX SARCO LTD Charlton House CHELTENHAM GL53 8ER telephone (0242) telex fax (0242) All correspondence should be sent to the above addressin the unlikely event that products need to be returned then these should be forwarded, clearly labelled and identified to our Returns Investigation Dept., Runnings Road, Kingsditch Trading Estate, Cheltenham, Glos, GL51 9NX Scottish Office (041) Printed in U.K. Copyright 1993

3 SECTION 1 GENERAL The BW7A series Butterfly valves are designed for use on water systems The butterfly valves should be stored in a cool and well ventilated, preferably air-conditioned, warehouse. Do not remove the protective coverings During long-term storage, open and shut the valves once every three months. In addition, apply rust-prevention oil on the plated parts, such as position indicators, worm shafts, bolts and nuts periodically, approximately once every six months After the valves are unpacked, avoid any point or spot loads on critical parts before use. 1.2 Additional Recommendations Before installation, check that the material type of the seat ring and disc meets the required specifications When handling butterfly valves, pick them up by the neck (the upper stem housing) with a nylon sling Install valves in a pipeline only after the flange weld zones have cooled down. Flanges should never be welded with a butterfly valve installed between them Sharp edges, gashes, or flash on the piping flanges should be filed off to prevent damage to the valve seat ring (Fig 1). The pitch circle of flange bolt holes should be exactly concentric with the piping bore The flange surfaces should be cleaned with compressed air then wiped with a solvent-soaked cloth. (Fig. 2) The pipeline should also be cleaned by compressed air or steam blower before installing the valve. Fig A short piece of pipe should be inserted between the butterfly valve and a check valve, bend, or pump, to prevent interfer ence with disc operation. (Fig.4) No gasket is required between the butterfly valve and the piping flanges. (Fig.4) Seat rings should be kept free from solvent. No oily substances except those made of NBR or Viton should come in contact with the seat ring Pipes whose walls are lined with resin should have the lining continuously extended up to the flange surface and the lining flared to cover the surface. The inside diameter as measured on the resin lining should be equal to or more than the rated size of the butterfly valve Special attention should be paid to the orientation of the butterfly valve when it is installed downstream from a bend. (Figs. 5 through 7) Fig The valve should be aligned exactly with the pipeline Before final tightening of flange bolts, make sure that the valve disc is not obstructed by the walls of the pipe when opened and closed. (Fig. 3) Fig. 2 Fig

4 Installation of a Butterfly Valve Adjacent to a bend Where practicable, the butterfly valve should be installed upstream from a bend. Fig. 5 Fig. 6 If a downstream installation is unavailable, the valve stem should have parallel orientation with the axis of the upstream piping. Fig. 7 Installation of a butterfly valve downstream from a bend with the stem not parallel to the axis of the upstream pipeline is not acceptable for the following reasons:- (1) differences in fluid velocity (pressure) on both sides of the disc may cause it to vibrate, and (2) in some cases, may cause erosion of the disc on the side having higher fluid velocity

5 SECTION 2 INSTALLATION After aligning the pipes, put two bolts into the bottom two flange holes for temporary support of the butterfly valve while it is being placed into position. (Fig. 8) Put two jacking bolts between the pipe flange as shown in the illustrations. By adjusting the jacking bolts and the two flange bolts, maintain the gap between the flanges at about 3 to 5 mm beyond its final position. Drop the butterfly valve into position. During this operation, care should be taken to keep the surfaces of the joints free from dents, scratches, etc. (Fig.9) Fig. 9 Fig. 8 Fig Before the butterfly valve has been lowered completely onto the bottom flange bolts, place another two bolts immediately below the upper lugs of the valve. Then ease the valve down until the lugs rest on the bolts. (Figs. 8 & 10) Remove the jacking bolts and install all remaining bolts. Partially tighten all bolts then align the valve. Once valve alignment is checked, tighten all bolts until the pipe flanges touch the metal surfaces of the valve. Take care to apply equal load to all bolts around the flange

6 2.2 Post Installation Procedures Pipelines should be flushed and cleaned after installation of valves Inspect and check for any leaks in the piping flanges, valve glands, or bottom cover by hydrostatic or pneumatic testing If any leaks are found retighten bolts carefully, making sure that the distribution of load to all bolts is uniform The butterfly valve should not be closed to hold a test pressure exceeding the rated pressure of the valve. If such testing is required, the valve should be removed and temporarily replaced by a blank flange During long-term shutdown of a pipeline the butterfly valve should be operated periodically at least once every two weeks The Butterfly valve should not be operated with the disk at 30 o or less for long periods. If this type of service is required, please consult our Technical Sales Department for specialist advice. 2.3 Effect of Flange Weld Types on the Butterfly Valve The inner wall of the pipe may sometimes interfere with valve disc operation depending upon the type of flange weld. The following instructions and table show two types of flange weld and applications of BW7A valves to these flanges. Weld Type A Weld Type B Typing Weld Type A Weld Type B Cast Iron Cement-Lined Minimum pipe bores allowing of pipe Pipes for Pipes made use of ISOA valves with weld Std Gas SCH40 SCH60 SCH80 Std Gas SCH40 SCH60 SCH80 water works by NKK type A (mm) Valve size Pipe Pipe X X X X 246 NOTE: (1) : applicable: (2) Possible change in bores due to sagging of pipes and allowable manufacturing tolerances in pipe diameter and thickness are taken into consideration in the above table. (3) Arc welded carbon steel pipes, JIS G3457, lined with rubber accepts BW7A valves of all sizes

7 SECTION 3 INSPECTION and MAINTENANCE Inspect the disc and seat ring for any corrosion or wear once a year If any abnormality is noticed during the operation, it may be that foreign matter is clogging the valve, or the seat ring is damaged. Remove the valve from the system for inspection. (Fig 11) Rust-prevention and lubrication procedures are outlined in the table below:- Fig. 11 Plated parts anti-rust oil Wd-40 or equivalent (indicator, bolts, nuts and worm shaft) Shafts and shaft sealings Molykote 111Dow Corning Gears Grease Shell Alvania No 2 Disc edge Silicon Grease Molykote 111 Dow Corning Removal Before removing a butterfly valve from a pipeline, first check that system pressure has been completely released. The system should also be completely drained before opening up a piping joint Shut the valve before loosening the flange bolts. Remove the bolts, leaving the bottom two in place. Open the flanges by means of jacking bolts, then remove the valve (Fig. 11). Overhaul and Re-assembly Overhaul and re-assemble for inspection or repair in accordance with the following procedures: Isolate the actuator electrically and pnuematically. Ensure valve is closed Remove the four bolts (33) which join the valve body and the actuator Grip the body in a vice and extract the actuator from the valve. The upper stem (3) will remain in position (Fig.12) Remove the machine screws (8) with a screw driver Grip the upper stem (3) in the vice and take out the valve body (1). (Fig.13) Remove the two bolts, and take out the bottom cover (6) and gasket (14). (Fig. 14) Now insert one of the bottom cover bolts into the threaded hole at the bottom end of the lower stem and turn it a few times. Remove the lower stem by pulling out the bolt (4). (Fig.15) Hold the disc (2) in both hands and push it out from the seat ring (12). (Fig 16) Insert a screw driver between the seat ring (12) and the valve body (1). (Fig. 17) Insert your fingers into the gap between the body (1) and the seat ring (12) and take it out (Fig 18). Fig

8 Upper stem (3) Gasket (14) Bottom cover (6) Fig. 13 Spring Bolt Fig. 14 Lower stem (4) Bottom cover bolt Seat ring (12) Disc (2) Fig. 15 Fig. 16 Body (1) Seat ring (12) Fig. 17 Fig

9 Proper Assembly of the Valve Before assembly, clean each component carefully with solvent, and check for damages or defects Replace the dust seal (Blow-out proof) and gaskets with new ones at each overhaul, even if they appear intact The lower stem (4) may be put temporarily in place to help align the seat ring (12). Remove after alignment Put the seat ring (12) into the body (1) Bottom first. Make sure that the holes of the two components match exactly (Fig. 19) To position the seat ring (12) to fit into the body (1), push the upper part of seat ring downward so that it curves like the letter U. Take care to keep the secondary seal ring (11) inplace (Figs. 19 and 20). Body (1) Fig. 19 Secondary seal ring (11) Seat ring (12) Apply grease to the stem Fig. 20 Disc (2) Fig

10 3.4.6 Check that the top and bottom holes of the seat ring completely match those of the body Apply silicone oil to the top and bottom ends of the disc (2) and place it into the bore of the seat ring (12) (Fig.21). Apply grease to the stem Lower stem (4) Fig Apply grease to the lower stem (4) and put it in place taking care not to do damage to the bottom of the seat ring (12) Body (1) Gasket (14) Bottom cover (6) Spring washer Bolt Fig. 23 Machine screw (8) (Fig 22) After the lower stem is fitted into the disc (2), place the gasket (14) and bottom cover (6) on the bottom end of the body (1) and tighten them with the bolts and spring washers (Fig.23) Looking down from the top of the body (1), check that the holes of the seat ring (12) and disc (2) are properly aligned with the valve. Dust seal (5) (Blow-out proof) Upper stem (3) Apply grease to the upper stem (3) and lower it down to fit into the disk, (2), aligning the flats. Insert the upper stem until the dust seal (5) is flush with the flange of the body, then (5) tighten down the two machine screws (8). (Fig. 24). Disc (2) Fig

11 SECTION 4 ACTUATOR ORIENTATION 4.1 Orientation BVAT actuators are normally installed with their major axis parallel to the pipeline. However, the actuator can be positioned above, below, or alongside the valve without affecting it's operation. The circumferential pinion gear allows re-orientation of the extended output shaft and housing to accommodate installation where physical obstructions might otherwise prove prohibitive Determine mode of operation of the valve (normally open or normally closed). 2. Determine direction of mounting of actuator (in line or cross line). SECTION 5 MOUNTING A PNEUMATIC ACTUATOR ON A BUTTERFLY VALVE Ensure valve is in fully closed position Mount Stop Plate and Actuator over valve spindle (Fig 25) Tighten the actuator flange using the bolts (33) and spring washers (34). (Fig 25) Operate the actuator to open and shut the valve to ensure full 90 movement Fig

12 SECTION 6 AIR SUPPLY 6.1. Air Supply BVAT actuators are factory lubricated hence a lubricated air supply is not required. The air must however be dry and clean. Any other non corrosive gas can be utilised as the operating medium as can light hydraulic oil Supply Pressure Operating Pressure - 6 barg 6.3. Supply connections - No solenoid BVAT - Connect air supply to port marked "A" (Fig 26) Connection size - G¼ BVAT actuator stroke direction can be reversed. To achieve this, remove gear/rack piston assembly, rotate 180 and re-install. This will reverse the direction of rotation of the output shaft Supply connections - solenoid All models of BVAT actuators can be fitted with an integral electrical solenoid valve. See Section 7 for details For BVAT actuators the air supply connection is on the mounting block. Connection size ¼" BSP. The exhaust is through a 1 / 8 " BSP male connection on top of the solenoid Air Consumption The following table shows the amount of air consumed per 90 stroke in litres. SECTION 7 SOLENOID VALVE 7.2. Selection BVAT actuators can be fitted with solenoid valves It is important that the correct solenoid valve is chosen to suit the voltage applied. The table below lists the options available. Table of Solenoid options Model MV11 MV12 MV13 MV14 Voltage 240/220 Vac 110 Vac 24 Vac 24 dc 7.2. Solenoid valve - Electrical supply Solenoid valves have IP65 plugs suitable for 7mm O/D cable Power consumption MV11 to MV14 = 4.5W Air to port Model A B Fig

13 SECTION 8 ACTUATOR MAINTENANCE 22½ - 45 Caution: The actuator must be isolated both pneumatically and electrically before any maintenance is carried out. 8.1 General Periodic checks should be performed to ensure all fasteners remain tight. All actuators are supplied with sufficient lubrication for their normal working life. If required, recommended lubrication for all actuators is Gulf Sovereign LC Grease. Depending upon the conditions under which the actuator is operating i.e. extended duty, non compatible operating medium or abnormal operating conditions, periodic replacement of internal 'O' rings is recommended. Kits containing all the necessary 'O' rings are available from Spirax Sarco. 8.2 Actuator Disassembly Disconnect actuator air and electrical supplies Remove actuator and mounting bracket from valve. Caution: All valves can trap pressurised media in the cavity. Isolate the piping system in which the valve is mounted then relieve any pressure in the valve body Remove the actuator bracket from the actuator to begin repair (note mounting position of bracket for easy reassembly). See fig Remove solenoid (if fitted) by removing bolts. Use care to retain 'O' ring seals Each end cap (19) is fitted no to the body (17) with a machined sleeve fit. Remove all screws (29) from both end caps. After the screws are removed gently prise off each end cap, being careful not to damage the end cap 'O' rings. Caution: Uniformly loosen all end screws on each end cap two or three turns at a time, in sequence, to relieve pre-load of the springs use caution when removing end caps The two pistons (18) can be removed by rotating the actuator shaft, driving the piston assemblies outward until the gear rack and pinion have disengaged Remove retainer ring (27) and the washer (28) from the shaft Remove the shaft (pinion gear) out through the bottom of the body New 'O' rings can be fitted if all actuator surfaces are clean and free from grit and scratches. If the inside walls of the body are scored the actuator will leak after rebuilding. Shallow marks barely detectable to touch are acceptable Lubricate the actuator thoroughly with grease. Apply a light film of grease to the 'O' rings. Fig 27 position with the piston assemblies situated at the body ends. (Normal position is that which provides the proper output shaft orientation - See Fig 27) Gently push each piston into the actuator body. Turn the top shaft extension clockwise. Do not allow the pistons to rotate. At the proper point of engagement between the centre gear and the piston assemblies, both pistons will move towards the centre of the body when the shaft is turned clockwise Once the centre gear and pistons are properly engaged ensure that smooth movement and 90 operation can occur without moving the pistons out of the actuator body. This is important!! Replace the actuator and caps (19) taking care to properly fit the sealing 'O' rings Replace the washer (28) over the top extension Install the shaft clip (27) into the mating groove on the top shaft extension. 8.4 Spring Replacement When replacing springs in a BVAT actuator ensure the springs are replaced in the end cap in the indentical position from which they were removed Important: Ensure they are positioned as shown in Fig Place springs in the end cap pocket using the alignment nibs cast into each cap With the springs pointing up and the end cap on a solid surface, place the actuator body over the springs and end cap Force the body down and begin by engaging 2 body bolts by hand through the end cap. Take each bolt up in small and equal turns. Once the end cap is temporarily secured to the body turn the actuator over to its normal position and uniformly take up the end cap bolts. 8.3 Actuator Reassembly Replace the top bearing (22) and bottom bearing (20) Replace the centre gear through the bottom of the actuator body. The bottom hole in the actuator body is a larger inside diameter than the top hole Very carefully align the pistons square to the body Align the centre gear so that the teeth will "pick up" the piston assembly's rack teeth when turning the top extension clockwise. Important Proper 90 rotation can only be assured if the centre gear teeth begin to mesh with the piston assemblys teeth at the "Proper Tooth" between these meshing pairs To ensure proper meshing of the teeth, rotate the centre gear 22½ - 45 (one or two teeth) counter clockwise from its natural Up to BVA200T BVA500T & 1100T Fig

14 Uniformly load all springs to prevent any from buckling Replace springs in other end cap in a similar manner. SECTION 9 COMPONENTS NOTCHED Handlever Parts List No. Name of Part Qty 1 Body 1 2 Disc 1* 3 Upper stem 1 4 Lower stem 1 5 Dust seal 1 (Blow-out proof) 6 Bottom cover 1 7 Spring pin 1 8 Machine screw 2 11 Secondary seal ring 2* 12 Seat ring 1* 14 Gasket 1* 15 Bolt 2 16 Spring washer 2 17 Actuator body 1 18 Piston 2 19 End cap 2 20 Bottom bearing 1 21 Springs? 22 Top bearing 1 23 'O' ring 2* 24 'O' ring 2* 25 'O' ring 1* 26 'O' ring 1* 27 Retainer ring 1 28 Washer 1 29 Screws 8 32 Cam flange 1 33 Bolt 4 34 Washer 4 * Available as spares Part No's 17 to 29 are shown on page