Consolidated. Consolidated Safety Valve Type 2700 Series INSTALLATION, OPERATION AND MAINTENANCE MANUAL. Type 2700 Series. CON-14 Revised 04/02

Transcription

1 Consolidated INSTALLATION, OPERATION AND MAINTENANCE MANUAL Consolidated Safety Valve Type 2700 Series Type 2700 Series P.O. Box 1430 Alexandria, Louisiana (USA) CON-14 Revised 04/02

2 H! ATTENTION Product Safety Sign and Label System Do not drop or strike. ATTENTION Hazards or unsafe practices which COULD result in product or property damage. If and when required, appropriate safety labels have been included in the rectangular margin blocks throughout this manual. Safety labels are vertically oriented rectangles as shown in the representative examples (left and below), consisting of three panels encircled by a narrow boarder. The panels can contain four messages which communicate: The level of hazard seriousness. The nature of the hazard. The consequence of human, or product, interaction with the hazard. The instructions, if necessary, on how to avoid the hazard. H! WARNING Know all valve exhaust/leakage points to avoid possible severe personal injury or death. WARNING Hazards or unsafe practices which COULD result in severe personal injury or death. H! CAUTION Wear necessary protective equipment to prevent possible injury. CAUTION Hazards or unsafe practices which COULD result in minor personal injury. H! DANGER Do not remove bolts if pressure in line, as this will result in severe personal injury or death. DANGER Immediate hazards which WILL result in severe personal injury or death. The top panel of the format contains a signal word (DANGER, WARNING, CAUTION or ATTEN- TION) which communicates the level of hazard seriousness. The center panel contains a pictorial which communicates the nature of the hazard, and the possible consequence of human or product interaction with the hazard. In some instances of human hazards the pictorial may, instead, depict what preventive measures to take, such as wearing protective equipment. The bottom panel may contain an instruction message on how to avoid the hazard. In the case of human hazard, this message may also contain a more precise definition of the hazard, and the consequences of human interaction with the hazard, than can be communicated solely by the pictorial. 2 Con-14

3 Contents Section Subject Page Product Safety Sign and Label System... 1 I. Safety Alerts... 4 II. Terminology for Safety Relief Valves... 5 Consolidated 2700 Series Valve Blow-Up... 7 Warranty Information... 8 Explanation of Nameplate... 8 Valve Operation... 9 III. Storage and Handling Prior to Installation IV. Recommended Installation Practices A. General Requirements B. Outdoor Safety Valve Installation C. Indoor Safety Valve Installation V. Hydrostatic Test Plug Removal Domestic and Export A. General Information B. Domestic Plugs C. Export Plugs VI. Testing A. General Information B. Application of Test Gags C. Presetting Adjusting Rings D. Steam Testing Instruction E. Hydroset/Electronic Valve Testing (EVT) VII. Disassembly Instructions A. General Information B. Specific Steps VIII. Inspection and Restoration of Parts A. General B. Specific Components IX. Re-Assembly A. General Information B. Specific Steps X. Trouble Shooting the Type 2700 Valve XI. Maintenance Tools & Supplies XII. Service Parts Inventory Philosophy XIII. Manufacturer s Field Service & Repair Program Glossary Service Department Locations Sales Office Locations Con-14 3

4 H! WARNING Improper use or repair of pressurized media or steam device may result in severe personal injury or death. H! WARNING Provide and use guarding to prevent contact with heated and/or pressurized parts. H! WARNING All potential hazards may not be covered in this manual. H! WARNING Heed all container label warnings. H! WARNING XXX Do not work with valves while under the influence of intoxicants or narcotics. H! WARNING Improper tools or improper use of right tools could result in personal injury or product damage. I. SAFETY ALERTS! READ UNDERSTAND PRACTICE 1. WARNING: Allow the system to cool to room temperature before cleaning, servicing or repairing the system. Hot components or fluids can cause severe personal injury or death. 2. WARNING: Always read and comply with safety labels on all containers. Do not remove or deface the container labels. Improper handling or misuse could result in severe personal injury or death. 3. WARNING: Never use pressurized fluids/gas/air to clean clothing or body parts. Never use body parts to check for leaks or flow rates or areas. Pressurized fluids/gas/air injected into or near the body can cause severe personal injury or death. 4. WARNING: It is the responsibility of the owner to specify and provide guarding to protect persons from pressurized or heated parts. Contact with pressurized or heated parts can result in severe personal injury or death. 5. WARNING: Do not allow anyone under the influence of intoxicants or narcotics to work on or around pressurized systems. Workers under the influence of intoxicants or narcotics are a hazard both to themselves and other employees and can cause severe personal injury or death to themselves or others. 6. WARNING: Incorrect service and repair could result in product or property damage or severe personal injury or death. See page WARNING: These WARNINGS are as complete as possible but not all-inclusive. Dresser cannot know all conceivable service methods nor evaluate all potential hazards. 8. WARNING: Use of improper tools or improper use of right tools could result in personal injury or product or property damage. 9. WARNING: This valve product line is not intended for radioactive nuclear applications. Some valve products manufactured by DFC may be used in radioactive environments. Consequently, prior to starting any operation in a radioactive environment, the proper health physics procedures should be followed, if applicable. 4 Con-14

5 1. CAUTION: Heed all service manual warnings. Read installation instructions before installing valve(s). 2. CAUTION: Wear hearing protection when testing or operating valves. 3. CAUTION: Wear appropriate eye and clothing protection. 4. CAUTION: Wear protective breathing apparatus to protect against toxic media. H! CAUTION NOTE: Any service questions not covered in this manual should be referred to Dresser s Service Department, Phone (318) II. Terminology for Safety Relief Valves Accumulation Accumulation is the pressure increase over the maximum allowable working pressure of the vessel during discharge through the pressure relief valve, expressed as a percentage of that pressure, or actual pressure units. Back Pressure Back pressure is the pressure on the discharge side of a safety relief valve: 1. Superimposed Back Pressure Superimposed back pressure is the pressure in the discharge header before the safety relief valve opens. Heed all service manual warnings. Read installation instructions before installing valve(s). H! WARNING a) Constant-Specify single constant back pressure (e.g., 20 psig/1.38 bar). b) Variable-Specify variable back pressure range using min. and max. limits (e.g., 0 to 20 psig/1.38 bar). 2. Built-up Back Pressure Built-up back pressure is pressure which develops at the valve outlet as a result of flow, after the safety relief valve has been opened. Blowdown Blowdown is the difference between set pressure and reseating pressure of a pressure relief valve, expressed as a percentage of the set pressure, or actual pressure units. Cold Differential Set Pressure Cold differential set pressure is the pressure at which the valve is adjusted to open on the test stand. This pressure includes the corrections for back pressure and/or temperature service conditions. Differential Between Operating and Set Pressures Valves in process service will generally give best results if the operating pressure does not exceed 90% of the set pressure. However, on pump and compressor discharge lines, the differential required between the operating and set pressures may be greater because of pressure pulsations coming from a reciprocating piston. It is recommended that the valve be set as high above the operating pressure as possible. Lift Lift is the actual travel of the disc away from the closed position when a valve is relieving. Know nuclear health physics procedures, if applicable, to avoid possible severe personal injury or death. H! CAUTION Wear necessary protective equipment to prevent possible injury. Con-14 5

6 Maximum Allowable Working Pressure Maximum allowable working pressure is the maximum gauge pressure permissible in a vessel at a designated temperature. A vessel may not be operated above this pressure, or its equivalent, at any metal temperature other than that used in its design. Consequently, for that metal temperature, it is the highest pressure at which the primary pressure safety relief valve is set to open. Operating Pressure The operating pressure is the gauge pressure to which the vessel is normally subjected in service. A suitable margin is provided between operating pressure and maximum allowable working pressure. For assured safe operation, the operating pressure should be at least 10% under the maximum allowable working pressure or 5 psi (.34 bar), whichever is greater. Overpressure Overpressure is a pressure increase over the set pressure of the primary relieving device. Overpressure is similar to accumulation when the relieving device is set at the maximum allowable working pressure of the vessel. Normally, overpressure is expressed as a percentage of set pressure. Rated Capacity Rated capacity is the percentage of measured flow at an authorized percent overpressure permitted by the applicable code. Rated capacity is generally expressed in pounds per hour (lb/hr) for vapors; standard cubic feet per minute (SCFM) or m 3 /min for gases; and in gallons per minute (GPM) for liquids. Relief Valve A relief valve is an automatic pressure-relieving device, actuated by static pressure upstream from the valve, a relief valve is used primarily for liquid service. Safety Relief Valve A safety relief valve is an automatic pressure-relieving device which may be used as either a safety or relief valve, depending upon application. A safety relief valve is used to protect personnel and equipment by preventing excessive overpressure. Safety Valve A safety valve is an automatic pressure-relieving device actuated by the static pressure upstream of the valve, and characterized by rapid opening or pop action. It is used for steam, gas or vapor service. Set Pressure Set pressure is the gauge pressure at the valve inlet, for which the relief valve has been adjusted to open under service conditions. In liquid service, set pressure is determined by the inlet pressure at which the valve starts to discharge. In gas or vapor service, the set pressure is determined by the inlet pressure at which the valve pops. Simmer Simmer is characterized by the audible passage of a gas or vapor across the seating surfaces just prior to pop. The difference between this start to open pressure and the set pressure is simmer, and is generally expressed as a percentage of set pressure. Valve Trim Valve trim includes the nozzle and disc. 6 Con-14

7 CONSOLIDATED 2700 SERIES VALVE H! SWAP ME 20 Part No. Nomenclature 1. Disc Holder 2. Guide 3. Base 4. Yoke 5. Upper Adj. Ring 6. Upper Adj. Ring Pin 7. Lower Adj. Ring 8. Lower Adj. Ring Pin 9. Spring 10. Top Spring Washer 11. Bottom Spring Washer 12. Bushing 13. Disc 14 Disc Collar 15. Lift Stop 16. Spindle 17. Compression Screw 18. Thrust Bearing 19. Com. Screw Adaptor ( Q Only) 20. Lifting Gear 21. Studs 22. Nuts THRU Q ORIFICE VENT (90 OUT OF POSITION) DO NOT PLUG 3 THRU Q ORIFICE Text Goes Here. Text Goes Here. Text Goes Here. Text Goes Here. Text Goes Here. Text Goes Here & 22 VALVE EXHAUST VALVE INLET Con-14 7

8 Warranty Information *WARRANTY STATEMENT - Dresser warrants that its products and work will meet all applicable specification and other specific product and work requirements (including those of performance), if any, and will be free from defects in material and workmanship. Defective and nonconforming items must be held for Dresser s inspection and returned to the original F.O.B. point upon request. INCORRECT SELECTION OR MISAPPLICATION OF PRODUCTS - DFC cannot be responsible for customer s incorrect selection or misapplication of our products. UNAUTHORIZED REPAIR WORK - DFC has not authorized any non-dresser affiliated repair companies, contractors or individuals to perform warranty repair service on new products or field repaired products of its manufacture. Therefore, customers contracting such repair services from unauthorized sources must do so at their own risk. UNAUTHORIZED REMOVAL OF SEALS - All new valves and valves repaired in the field by Dresser Field Service are sealed to assure the customer of our guarantee against defective workmanship. Unauthorized removal and/or breakage of this seal will negate our warranty. *Refer to Dresser s Standard Terms of Sale for complete details on warranty and limitation of remedy and liability. Explanation of Nameplate The valve nameplate contains several necessary pieces of information necessary to the proper operation of the valve. Included are: Valve Type ASME, and National Board of Boiler and Pressure Vessel Inspectors Approval Stamp Serial Number Set Pressure or Opening Pressure Disc Lift Operating Temperature Capacity 2700 Valve Series nameplate is located on the base of the valve, to the left of the Adjusting Ring Pins. If the nameplate is missing, a duplicate nameplate can be supplied by Dresser Flow Control. To order the replacement nameplate, call the DFC Field Service Supervisor at a/c (318) , with the valve serial number as stamped on the top of the discharge flange of the valve. VALVE IDENTIFICATION VALVE TYPE CODING B W B Series Temp. Class Orifice Butt Pressure Weld Designation Class Inlet ORIFICE SIZE DESIG- BORE NATION DIAMETER Q TABLE I PRESSURE RANGE No CLASS OPERATING TEMPERATURE LTR. B D DEG. F (MAX) Con-14

9 Valve Operation The Type 2700 Safety Valve operates on the principle that when steam pressure at the valve inlet, acting over the area of the disc seat (C) and bushing seat (A), generates a force that approaches that produced by the spring, the valve opens. Minimal leakage into the volume generated by the lower adjusting ring (B) causes additional force over a larger area acting on the disc holder (E), causing the valve to pop open. Proper adjustment of the upper adjusting ring allows the disc to go into full lift at overpressure. When full lift is attained, lift stop (H) rests against the yoke to prevent hunting, thus adding stability. When the inlet pressure drops to the desired closing pressure, the disc (C) moves downward, causing the valve to close. The arrangement of the disc and its complement of parts, that is disc holder (E), spindle (G), disc collar (F), and lift stop (H), allow the disc to seek its natural position for tight closure. The THERMOFLEX Disc design, by allowing for the rapid equalization of temperature around the valve seat, provides a degree of tightness far above that offered by competitive valves. H F C G E D B A FIGURE 1 Con-14 9

10 H! ATTENTION III. Storage and Handling Prior to Installation Safety valves should be stored in a dry environment to protect them from the weather. They should not be removed from the skids or crates until immediately prior to installation. Flange protectors and sealing plugs should remain installed until just prior to installation. Safety valves, either crated or uncrated, should never be subjected to sharp impact. This would be most likely to occur by bumping or dropping during loading or unloading from a truck or while moving with a power conveyor, such as a fork lift truck. The valve, either crated or uncrated, should always be kept with the inlet down (i.e., never laid on its side), to prevent misalignment and damage to internals. Even crated valves should always be lifted with the inlet down. Lift only in vertical upright position. H! ATTENTION Uncrated valves should be moved or hoisted by wrapping a chain or sling, around the discharge neck, then around the upper yoke structure, in such manner as will ensure that the valve is in vertical position during lift, (i.e., not lifted in horizontal position). Never lift the full weight of the valve by the lifting lever. Never hook to the spring to lift. When safety valves are uncrated and the flange protectors removed, immediately prior to installation, meticulous care should be exercised to prevent dirt from entering the outlet port while bolting in place. While hoisting to the installation, care should be exercised to prevent bumping the valve against steel structures and other objects. IV. Recommended Installation Practices A. General Requirements The valve should be installed to meet all the requirements of Figure 2 (below). ANCHOR DISCHARGE PIPING SOLIDLY TO BLDG. STRUCTURE Handle valve carefully. Do not drop or strike. RADIAL CLEARANCE REQUIRED WHEN VALVE IS OPERATING H! CAUTION BORE EQUAL TO MINIMUM VALVE OUTLET DIAMETER VERTICAL CLEARANCE REQUIRED WHEN VALVE IS OPERATING VENT (SEE FIGURE 3.) BODY DRAIN DRAIN DRAIN FLANGED INLET SHOWN WELDED INLET SIMILAR Prevent dirt from entering outlet or inlet port. * *MAX. DIMS. 3" 150# - 7-1/4 (185MM) 6" 150#-12-1/2 (318MM) 8" 150#-16 (407MM) 3" 3OO# - 7-5/8 (194MM) 6" 3OO#-12-7/8 (327MM) 8" 3OO#-16-3/8 (416MM) FIGURE 2 BORE EQUAL TO MINIMUM OF VALVE INLET DIAMETER 10 Con-14

11 The safety valve shall be connected to the header independent of any other connection, and attached as close as possible to the header, without any unnecessary intervening pipe or fitting. Necessary intervening pipe or fittings shall not be longer than the face-to-face dimension of the corresponding tee fitting of the same diameter and pressure, per ANSI/ASME Standards. No valve of any description should be placed between the safety valve and the header, nor on the discharge pipe between the safety valve and the atmosphere. In no case may the inlet piping to the valve have a flow area less than the area of the valve inlet. Excessive pressure loss at the inlet of the safety valve will cause extremely rapid opening and closing of the valve, which is known as chattering. Chattering may result in lowered capacity as well as damage to the seating surface of the valve. Severe chattering can cause damage to other parts of the valve. The following recommendations will assist in eliminating the factors that produce chatter: 1. The downstream corner of the header nozzle must be rounded to a radius of not less than 1/4 of the opening diameter. (See Fig. 3) 2. Pressure drop due to friction flow to the inlet of the valve should not be greater than 50% of the expected blowdown of the safety valve. A DRAIN Orifice Designation * 4* 6 7Q ANCHOR DISCHARGE PIPING SOLIDLY TO BUILDING STRUCTURE TABLE II 2700 YOKE VENT SIZES Yoke Vent Size (NPT) 1/2 1/2 1/2 3/4 3/4 1 1 *#5 is a smaller orifice than #4. FABRICATED DRIP PAN SHOWN AS CLOSE POSSIBLE YOKE VENT SCHEDULE 40 PIPE To decrease the effects of a phenomenon known as sonic vibrations, or flow induced vibrations, the following recommendations are made: SECTION A-A FIGURE 3 1. Safety valves should be installed at least eight to ten pipe diameters downstream from any bend in a steam line. This distance should be increased when the valve is installed on the horizontal section of a header which is preceded by an upward section. 2. Safety valves should not be installed closer than eight to ten pipe diameters either upstream or downstream from a diverging, or a converging, Y. 3. In cases where a piping configuration renders the above two recommendations impractical, or impossible, the downstream corner of the header nozzle inlet should be rounded to a greater extent than the upstream corner. The header nozzle entrance should be rounded so the radius at the downstream corner will be equal to a minimum of 1/4 of the nozzle diameter. The radius should be reduced gradually, leaving only a small portion of the upstream corner with a smaller radius. (See Fig. 3) 4. Safety valves should never be installed, in a steam line, in a position directly opposite to a branch line. A UNION Con-14 11

12 Excessive line vibrations are known to produce shifts in safety valve set pressures. Vibrations may possibly introduce chatter, causing damage to the valve and reduce its capacity. This vibration also contributes to increased incidents of seat leakage. Considerations should be given to eliminating this problem prior to installing the valve on the unit. Steam flowing vertically out a discharge elbow produces a downward reaction on the elbow. Effects of reaction force, vibration, and seismic loads, on all valve components and discharge piping, should be considered when designing the valve system.refer to ANSI B.31.1, Non-Mandatory Appendix II, Dresser Product Information Sheet SV/PI-15, and Dresser Bulletin SV-5 for further information. For optimum performance, safety valves must be serviced regularly and otherwise maintained. So that servicing can be properly performed, valves should be located in a manner that allows for easy access. Sufficient working space should be provided around and above the valve to permit access to adjusting rings. If two or more valves are located close together, the outlets should be parallel so as to offer as much protection as possible to personnel repairing, or working close to, the safety valve. Because foreign material passing into, and through, a safety valve is damaging, the system on which the valve is installed must also be inspected and cleaned. New systems are prone to contain welding beads, pipe scale, and other foreign materials which are inadvertently trapped during construction, and destroy the valve seating surfaces the first few times the valve opens. With regard to weld-end inlet valves, completely assembled valves may be installed without disassembly being necessary at the time of welding. During welding, the valve neck should be insulated to reduce thermal stresses. When stress relieving, insulation should also be utilized to reduce thermal stresses. In service, the valve neck should be insulated at least to the point of the inlet neck/valve body-bowl juncture. Safety valves should be installed in a vertical position. Nominal tolerance on vertical installation is plus or minus 1 degree. The discharge area of the outlet piping from a safety valve should not be less than the area of the outlet connection. Where more than one safety valve is connected to a common outlet pipe, the area of the pipe should not be less than the combined area of the outlet connections to the safety valves. All safety valve discharges should be piped so that the effluent is discharged clear from walkways or platforms. Ample provision for gravity drain should be made in the discharge pipe at, or near, each safety valve where water, or condensation, may collect. Each valve has an open gravity drain through the body, below the level of the valve seat, and this drain should be piped to a safe discharge area. If a silencer is used on a safety valve, it should have sufficient outlet area to prevent back pressure from interfering with the proper operation and discharge capacity of the valve. The silencer or other piping components should be constructed so as to avoid the possibility of creating corrosion deposit restrictions in the steam passages. Exhausts, drains, and vents must be installed so that they will not impose undue stresses on the safety valve. Any such stresses can produce body distortion and leakage. Therefore, the following recommendations are provided: 1. Discharge piping should not be supported by the valve. The maximum weight on the outlet of the valve should not exceed the weight of a flange and short radius elbow, plus a twelve (12) inch (304.8 mm) straight length of standard weight thickness pipe (with drip pan). 2. Clearance between the valve exhaust piping and the discharge stack should be sufficient to prevent contact when considering thermal expansion of the header, valve, and discharge stack. Movements due to vibration, temperature changes, and valve reaction forces should also be considered, to ensure adequate clearance between the exhaust piping and the discharge stack. 3. Flexible metal hoses are not generally recommended, but if used to connect valve outlets to discharge stacks, they must be of sufficient length, and be configured/installed in such a manner, that they will not become solid in any one position. Better results are obtained if the hoses are installed so that they will permit movement by bending, rather than by stretching and compressing along their length. 12 Con-14

13 The yoke can be vented to the atmosphere as in Figure 2. Precautions should be taken to vent the yoke in such a manner that it will exhaust into a safe area to prevent injury to personnel near the valve. The yoke vent piping must not be connected to the body drain piping. Do not plug the yoke vent hole or reduce vent hole pipe size, (Reference Table II), as this could lead to valve malfunction and damage. Precautions should be taken to prevent accumulations of foreign material or water in the vent pipe. This vent is a critical part of the valve system for controlling valve blowdown and lift. All face surfaces which require gaskets, to seal pressure, shall be inspected for cleanliness, or any defects that can cause leakage. Burrs, mashed serrations, uneven surfaces, etc., are all possible leakage producing defects. Proper gasket sizes and pressure ratings should be checked prior to starting valve installation. It is of utmost importance that the gaskets used be dimensionally correct for the specific flange, and that they fully clear the valve inlet and outlet openings. Gaskets, flange facings, and bolting should meet the service requirements for the pressure and temperature involved. Other valve installation considerations include: 1. Install the inlet gasket, if required, on the header mounting flange. Check for cleanliness, surface alignment condition, gasket condition, etc. When possible, inlet studs on the mounting flange should be used to guide the valve on the header mounting flange. Inlet studs should be lubricated with the appropriate lubricant. 2. When installing flanged valves, the flange bolts must be pulled down evenly to prevent body distortion, misalignment, and leakage. 3. With valve in position, screw on the stud nuts until all nuts are finger tight. An initial torque shall be placed, in turn, on each stud nut. Increase the torque progressively until the final torque is applied. Upon completion, recheck each stud nut s torque. Required torque will vary with bolting material and gaskets used. See your company engineering or specification department for details on torquing sequence and torque values. As an extra precaution, the gap between the two mating flanges should be checked during the torquing process to ensure that the flanges are being pulled together evenly. A final inspection and review should be made to ensure that all of the requirements for bolting the valve inlet have been implemented. 4. The outlet piping may now be installed. A complete inspection of components and their cleanliness is to be made prior to further work. Studs are to be lubricated with an appropriate lubricant. 5. Install the outlet gasket, studs and nuts. Stud nuts are to be pulled down finger tight. An initial value of torque is to be applied. The additional procedures outlined, in Step 3 are also to be followed. After being assured that the valve is properly installed, the drainage piping from the valve body-bowl is to be connected. This line also must be flexible, so it will not create stress on the valve under operating conditions. Prior to completing the installation, a visual check should be made to ensure that the valve lifting lever has room and is free to operate. At the time of installation, an inspection of the valve should be made to confirm that all adjustment components (i.e., ring pins, cap, etc.) are properly locked and sealed, as required by the ASME Code. For operational hydrostatic tests at the valve inlet, which do not exceed valve set pressure, the valve should be gagged. Refer to the final Field Testing portion of this manual (i.e., Section VI) for proper techniques. Ensure that the gag is removed upon completion of the inlet hydrostatic test. Prior to startup of the unit on steam, the sections of this manual which specify requirements for set pressure testing should be reviewed. For conditions where the valve is subjected to high steam pressures (i.e., those exceeding normal operating conditions), preparations should be made to gag the valves. These preparations should then be cleared with the boiler manufacturer and DFC Engineering. Refer to Section VI. B.3 of this manual for the proper gagging techniques. Con-14 13

14 The safety valve should be tested with full steam pressure to ensure that the safety valve installation has been properly accomplished. In some cases this is not practical, thus the use of the CONSOLIDATED Hydroset, or the Electronic Valve Tester (EVT), should be considered. For valves being tested for set pressure by using a Hydroset or EVT, only the set pressure is being verified. Other factors such as blowdown, lift, reaction force, proper discharge stack sizes and effects of thermal expansion cannot be determined, using these setting devices. Full flow steam testing is recommended at initial start-up to adjust blowdown and verify proper installation. Proper adjusting ring position can then be recorded and maintained when valves are serviced. Vent and drain piping should have a union connection to facilitate valve removal or servicing in place. (See Fig. 2) B. Outdoor Safety Valve Installation Safety valves operating under the best possible conditions (i.e., of favorable operating gap, relatively stable ambient temperatures, the absence of dirt and in relatively still air) will provide the maximum degree of safety, tightness and dependability. When a safety valve is installed in an outdoor location, it may be exposed to wind, rain, snow, ice, dirt and varying temperatures. Therefore, the following recommendations are made for proper protection, and to ensure that operational dependability can be restored to a level near that of the valve installed under ideal conditions: The inlet neck of the safety valve and safety valve body, up to the top of the base, should be insulated. The exterior surface of any such insulation should be made weather-proof by any suitable means. In addition to maintaining a more even temperature within the valve body, especially during widely fluctuating ambient temperatures, this insulation will effectively reduce thermal stresses, due to high temperature gradients, through the walls of the safety valve nozzle. Spring covers should be used to stabilize (as nearly as possible) the temperature of the spring, to prevent the accumulation of snow and ice between the coils of the spring, and to prevent dirt and fly ash from accumulating between the coils of the spring. Lifting gear covers should be installed to prevent ice, dirt and fly ash from accumulating in areas inside the safety valve cap. H! WARNING C. Indoor Safety Valve Installation Indoor valve installations should have inlet necks insulated only up to the underside of the valve body. Considerations should be given to ambient temperature changes greater than 100 F (37.8 C), because of possible set point changes which may occur. Know all valve exhaust/leakage points to avoid possible severe personal injury or death. 14 Con-14

15 V. Hydrostatic Test Plug Removal-Domestic & Export HYDROPLUG A. General Information Flanged inlet safety valves shipped without Hydrostatic Test Plugs should be removed from the boiler during hydrostatic tests and boiler nozzles blanked off to prevent possible valve damage. All valves shipped outside the continental United States are shipped with an export hydroplug (See Fig. 6). All welded inlet valves shipped within the continental United States are shipped with a domestic hydroplug (See Fig. 5), unless the customer specifically requests otherwise. All flanged inlet valves shipped within the continental United States are shipped without a hydroplug, unless one is specifically requested by the customer. Valves shipped with either type of hydroplug are identified by a Red on White CAUTION TAG which is attached to the valve by wires extending through the drain hole in the valve body. (See Fig. 4) FIGURE 4 Hydrostatic test plugs must be removed prior to firing boiler. The hydrostatic plugs are placed in the bore of the valve, inside the seating surface. Their purpose is twofold. First, they effect closure at a point differing from the seating surface of the valve so that, if the valve is lifted on hydrostatic test, the seating surface is not as likely to be damaged. Second, by raising the disc of the valve off its seat and increasing spring compression, the set pressure of the valve is increased to a point where the valve will not leak at one and one-half times design boiler pressure. It is not necessary to gag the safety valves when hydrostatic plugs are used. These plugs must, of course, be removed from the valves prior to placing the boiler in service. However, they should be retained, and reinstalled, whenever a hydrostatic test is conducted which exceeds the low set valve pressure. Before starting to disassemble the valve, be sure that there is no steam pressure in the drum or header. H! DANGER Do not disassemble valve with pressure in drum or header, as this will result in severe personal injury or death. Con-14 15

16 B. Domestic Plugs To remove the domestic plug, the following steps must be followed: 1. Remove the cap assembly, adjust release nut to 2nd hole from the top of the spindle and install cotter pin. 2. Back off the yoke stud nuts uniformly until compression screw engages release nut. Now remove yoke stud nuts. 3. Remove yoke and spring assembly, (See Fig. 7), from base, being careful not to damage the disc. 4. Remove the hydrostatic test plug from the seat bushing. This may be accomplished by inserting a threaded rod into the tapped hole in the plug and lifting up until free from bushing. Care should be taken as not to damage the seat bushing. 5. Remove the disc from the disc holder by turning clockwise until it is disengaged from spindle threads. NOTE: Hold the disc holder against the disc adjusting collar during this step, otherwise the disc holder will fall from the spindle and become damaged. CAP DROP LEVER UPPER & LOWER ADJ. RING PINS 3 THRU Q ORIFICE CAP LEVER PIN LEVER TOP WASHER ARM SPINDLE YOKE COMPRESSION SCREW COMPRESSION SCREW ADAPTOR (5 THRU Q ORIFICE) THRUST BEARING TOP SPRING WASHER RELEASE NUT COMPRESSION SCREW COMPRESSION SCREW LOCKNUT THRUST BEARING TOP SPRING WASHER SPRING LIFT STOP STUDS & NUTS DISC HOLDER GUIDE VENT DISC COLLAR UPPER ADJ. RING DISC LOWER ADJ. RING DRAIN SEAT BUSHING BASE FIGURE 5 SERVICE PLUG 6. Lap the disc and seat bushing and thoroughly TABLE III clean the seats with a clean cloth. 7. Lubricate the spindle tip with Anti-Seize, and TORQUE OF YOKE NUTS assemble the disc and disc holder to spindle by Orifice Designation Nut Torque turning the disc until the dropout threads disengage Ft. Lbs Ft. Lbs. 8. Reassemble yoke and spring assembly (See Fig Ft. Lbs. 7) into base, being careful not to damage the disc. 5* 170 Ft. Lbs. Locate the yoke vent to the side of the valve. The 4* 375 Ft. Lbs. lug on the top spring washer should be on the Ft. Lbs. right side of the valve when facing the outlet. 7Q 375 Ft. Lbs. 9. Replace the yoke and the stud nuts. Tighten the *#5 is a smaller orifice than #4. stud nuts according to Table III. 10. Remove cotter pin from release nut and position release nut so that 1/8 inch (3.175mm) of clearance is visible between lifting fork and release nut, then install cotter pin. 11. Install cap and lever assembly. 12. Valve is now ready for the initial field test on steam in order to check valve set point and blowdown. 16 Con-14

17 C. Export Plugs When hydrostatic plugs are installed in 2700 Valves scheduled for shipment to foreign countries, the disc is removed and dipped in preservative, then packed in a box. The package is then inserted into the valve outlet. To remove the special export plug, the following steps must be followed: 1. Remove the cap assembly, adjust release nut to 2nd hole from the top of the spindle and install cotter pin. 2. Back off the yoke stud nuts uniformly until compression screw engages release nut. Now remove yoke stud nuts. 3. Remove yoke and spring assembly, (See Fig. 7), from base. 4. Remove hydrostatic plug by turning until it is disengaged from spindle threads. SPINDLE DISC HOLDER EXPORT HYDROPLUG SEAT BUSHING FIGURE 6 NOTE: Hold the disc holder against the disc adjusting collar during this step, otherwise the disc holder will fall from the spindle and become damaged. 5. Remove the seal peel preservative from the disc. 6. Lap the disc and seat bushing, thoroughly clean the seats with a clean cloth. 7. Lubricate the spindle tip with Anti-Seize, and assemble the disc and disc holder to spindle by turning the disc until the dropout threads disengage. 8. Reassemble yoke and spring assembly (See Fig. 7) into base being careful not to damage the disc. Locate the yoke vent to the side of the valve. The lug on the top spring washer should be on the right side of the valve when facing the outlet. 9. Replace the yoke and the stud nuts. Tighten the stud nuts according to Table III. 10. Remove cotter pin from release nut and position release nut so that 1/8 inch (3.175mm) of clearance is visible between lifting fork and release nut, then install cotter pin. 11. Install cap and lever assembly. 12. Valve is now ready for the initial field test on steam in order to check valve set point and blowdown. FIGURE 7 Con-14 17

18 VI. Testing A. General Information Upon completion of hydrostatic testing of the boiler, but prior to placing the boiler in service, ENSURE THAT THE HYDROSTATIC TEST PLUGS ARE REMOVED FROM ALL VALVES. All Type 2700 Safety Valves are steam tested at the factory to verify set pressure adjustability and seat tightness. Every valve is set to have a clean popping action and to reseat tightly. However, because the boiler used in setting the valves has a small capacity, compared to the capacities of the Type 2700 Valves, the valves are factory set with a long blowdown to prevent chattering under initial start-up conditions. Final adjustments should be made on the operating system with conditions approximately those that will be realized under actual operating conditions. Note: DFC recommends full flow steam testing upon initial start up. Adjusting ring settings are initial adjustments only and are not intended to be final adjustments. The use of a DFC Hydroset or EVT, unit can serve to establish set pressure but cannot be used for verifying blowdown, lift, etc. (For additional information, see page 12, of this manual). It is recommended that the safety valves be tested and adjusted with the boiler isolated. Factors which can affect valve operation, and which should be considered when initially setting a valve, are as follows: 1. Ambient temperature near the valve and valve temperature stabilization. 2. Line vibration. 3. Valve capacity versus rated flow through the line on which the valve is mounted. 4. Discharge stack or drain piping binding. 5. Flow induced vibrations or pressure pulsations set up by upstream bends. Valve inlet nozzle configuration, or other internal piping configuration problems. 6. High water level in the drum. When the valves are subjected to working hydrostatic tests not exceeding the set pressure of the low set valve, valves may be gagged rather than using hydrostatic test plugs. For higher pressures, hydrostatic plugs should be used. A common source of safety valve trouble is over-gagging. During hydrostatic testing, and during safety valve setting, gags should be applied only hand tight. During setting, overgagging will also cause damage to the seating surface and result in seat leakage. The gag load applied should be only enough to ensure that the valves do not lift at the expected overpressure. During start-up, gags should never be applied when the boiler is cold. The spindle of the safety valve expands considerably with the temperature increase. If it is not free to expand with this temperature change it may become seriously overstressed and bent. Except for hydrostatic tests, boiler pressure should be brought up to within 80% of the pressure of the low set valve before applying gags. Tighten the gags of drum and superheater valves finger tight. When adjusting the ring positions of a valve, the valve must be gagged to prevent accidental lifting and personal danger. If testing the set pressure of a valve, the other valves in the system should also be gagged. 18 Con-14

19 B. Application of Test Gags (All Pressures) 1. Refer to Figure 5 on page 16. Remove top lever pin and top lever, then loosen the cap screw. Remove cap and drop lever as an assembly. The release nut is fixed to the spindle by means of a cotter pin. Note that the release nut does not quite engage top of compression screw. 2. Center the test gag in the exposed end of the SPINDLE and hook the legs of gag under the sides of the YOKE. Do not apply the gag load until the system steam pressure is equal to 80% of the pressure to which the low set valve is adjusted. 3. Apply the gag load by turning the gag screw clockwise. If the gag on any valve has not been tightened sufficiently, the valve will leak. On steam service the leakage is accompanied by a Sizzling sound. If this occurs, the hydrostatic test pressure or steam pressure should be reduced until the valve becomes tight and, then, the gag should be tightened still further. This procedure must be followed exactly, since it is very difficult to stop the leak by additional gagging once it has started. Any attempt to stop the leakage through the valve, without first lowering the system pressure, could result in damage to the valve seats. 4. After the hydrostatic test or steam test is completed, the gags should be removed when the hydrostatic pressure has been reduced to 80% to 90% of the pressure of the low set valve. Note: Under no circumstances should the gags be left on the valves during normal boiler operation. C. Presetting Adjusting Rings ORIFICE Q TABLE IV LOWER RING SEAT LEVEL ADJUSTMENT IN NOTCHES (Column A) UPPER RING SEAT LEVEL ADJUSTMENT IN NOTCHES (Column B) H! WARNING GAG Gag safety valve during ring adjustments to avoid possible severe personal injury or death. 1. Remove the caps on all valves to be set on the steam drum and main steam line. 2. Install a currently calibrated pressure gauge on the drum near the valve being set. When main steam valve are to be set, install the calibrated gauge upstream from the valves on the main steam line to read line pressure. 3. After the pressure in the boiler has increased to 80% of operating pressure, install gags on all boiler valves not being tested. Gags should be installed hand tight, (no wrenches or mechanical force). Con-14 19

20 4. On the valve to be tested, use the following procedure and Table IV, to bring the adjusting ring to seat level. a) Gag the valve to prevent the disc from accidentally lifting from the seat during adjustment. b) Remove both service port plugs. c) Remove the upper ring pin. d) Move the upper ring until it is level with the disc holder. e) From this point, move the upper adjusting ring down, (from right to left as viewed through the service plug hole), counting the number of notches until the number in Column B in Table IV, appropriate to the orifice size is reached. This will establish the upper adjusting ring at seat level. f) Adjust the upper adjusting ring as indicated in the upper ring Column of Table V use either the Saturated Column or Superheated Column as conditions warrant g) Replace the ring pin in the valve to hold the upper adjusting ring in position without binding. h) Remove the lower ring pin. i) Move the lower adjusting ring up until it contacts the disc holder. j) After referring to Table IV, lower the adjusting ring the number of notches indicated in Column A. This setting will place the lower adjusting ring at seat level. k) Once the lower adjusting ring is at seat level it can be preset to the beginning test position by moving the adjusting ring down one notch for each 600 PSI or part thereof. (Example: 1,000 PSI Set Pressure = 2 notches.) l) Replace the adjusting ring pin in the valve to hold the lower adjusting ring in position without binding. 5. Wire the adjusting ring pins together to prevent them from loosening and vibrating out under pressure. 6. Replace the service port plugs. 7. Remove the gag from the valve to be tested, and reinstall the cap and lever assembly on the valve. 8. Now the valve is ready for steam testing. D. Steam Testing Instructions 1. Attach a rope to the lifting lever on the valve to be tested. 2. Increase the boiler pressure at a rate not to exceed 2 PSI per second. Note and record the pressure indicated on the pressure gauge when the valve pops open. After the valve pops open, reduce the fire in the boiler and lower the pressure until the valve closes, note and record the pressure when the valve closes. If in raising the boiler pressure, the valve doesn t open within 3% overpressure (for ASME Section I valves), or 10% overpressure (for ASME Section VIII valves), reduce the fire in the boiler and pull the rope to open the valve. 3. Determine if the valve popping point and reseating points comply with the ASME requirements for valve operation as recorded in Table V. (See ASME Boiler and Pressure Code Section I, or Section VIII Valve Operation Standards for more details). To determine which standard to use, look at the nameplate on the valve. The symbol that is present on the nameplate will indicate the proper standard of operation. (See Table VI) 4. If the valve operation is in compliance with the standard, proceed to step If the valve is not in compliance, reduce boiler pressure to approximately 85% of valve set pressure. GAG the safety valve being adjusted. a) If set pressure is out of compliance turn the compression screw one sixth of a turn (clockwise to raise set pressure, and, counterclockwise to lower set pressure). Retest, and note the change in set pressure for one sixth turn-then calculate the number of turns needed to bring the set pressure to the desired pressure. Adjust as necessary. b) If the blowdown is excessive, raise the upper adjusting ring (5 to 10 notches). If the blowdown is insufficient, lower the upper adjusting ring (5 to 10 notches). Re-test as in step 2, if the blowdown is not within specification repeat step Remove the gag, and repeat Step 2, raising the pressure until the valve pops then proceed with the following steps until the subject valve is in compliance with the appropriate standard. 7. After one pop has been determined to be in compliance, test the valve two more times for consistency of set pressure and blowdown. Allow a minimum of 10 minutes between pops. If the operation remains in compliance with the standard, reduce the boiler pressure to approximately 85% of the set pressure and seal the valve cap and adjusting ring pins. 8. Proceed to the next valve to be tested. 9. When all valve have been tested and sealed, return the boiler to normal operating pressure. (See Table VII.) 20 Con-14

21 PRESETTING INFORMATION FOR USE ON 2700 SERIES SAFETY VALVES Set Pressure Lower Upper Ring Orifice (See Note 2 Below) Ring Position Position from to (See Note 1 Below) Saturated Superheated # TABLE V N down per each 600 psig not to exceed 5N down 20N 20N 15N 10N 10N 5N Seat Level Seat Level 5N 10N 10N 15N # N down per each 600 psig not to exceed 5N down 20N 20N 15N 10N 10N 5N Seat Level Seat Level 5N 10N 10N 15N # N down per each 600 psig not to exceed 5N down 25N 25N 20N 15N 15N 25N Seat Level Seat Level 10N 20N 20N 20N # N down per each 600 psig not to exceed 5N down 50N 40N 40N 40N 45N 65N Seat Level 10N 10N 15N 25N 25N # N down per each 600 psig not to exceed 5N down 55N 50N 45N 45N 45N 60N Seat Level 10N 15N 20N 25N 25N # N down per each 600 psig not to exceed 5N down 70N 65N 60N Seat Level 10N 20N Q. NOTE: All set pressures 900 1N down per each 600 psig not to exceed 3N down Set upper adjusting ring flush with seat level. Set upper adjusting ring 1/2 turn below seat level. 1. If the valve is to be set on superheated steam, establish 1. the position of the lower adjusting ring at seat level. 2. If set pressure is under 300 psig or valve is not listed on 1. above chart, contact the Consolidated Field Service 1. Department for setting information. Con-14 21

22 ASME Boiler and Pressure Vessel Code Section and Symbol V CODE SYMBOL STAMP ASME Section I UV CODE SYMBOL STAMP ASME Section VIII TABLE VI Set Pressure Tolerance (The valve must POP open within the range indicated below.) If valve set pressure is less than or equal to 70 psig +/-2 psig If valve set pressure is 71 psig up to and including 300 psig +/-3% of set pressure If valve set pressure is 301 psig up to and including 1000 psig +/-10 psig If valve set pressure is 1001 or greater +/-1% of set pressure If valve set pressure is less than or equal to 70 psig +/-2 psig If valve set pressure is 71 psig or greater +/-3% of set pressure Blowdown Requirements After opening, the valve must reclose within a range of 98% to 96%, however, if the valve set pressure is 100 psig or less the valve must reclose within a range of 2 to 4 psig below set pressure. After opening the valve must reclose before the system pressure returns to normal operating pressure. TABLE VII RECOMMENDED OPERATING GAP Boiler Design Pressure, psig (KPa) Over 15 to 300 (100 to 2100) Over 300 to 1000 (2100 to 6900) Over 1000 to 2000 (6900 to 13, 788) Minimum Differential as a Percent of Boiler Design Pressure 10% but not less than 7 psi (48 KPa) 7% but not less than 30 psi (210 KPa) 5% but not less than 70 psi (483 KPa) 22 Con-14