 |
|
|
||||||
 |
||||||||
 |
||||||||
|
||||||||
 |
||||||||
| FAQ's : |
Pilgrim International's Frequently Asked Questions (FAQ's) and Discussion Forum: In order to strive to meet our customers expectations, to ensure that we are continually refining and developing our product offering, Pilgrim International have provided this open forum. The 'Coupling Concepts' arena allows technical issues to be discussed, ideas and techniques shared and all are posted for other end users and potential customers to benefit from. Please see a selection of Pilgrim's own FAQ's we have developed. Should your own questions not be have been covered sufficiently please feel free to post them to us directly here , and we will respond accordingly. B) FEATURES OF PILGRIM RADIAL FIT BOLT C) FEATURE OF THE CHAT - COUPLING HOLE ALIGNMENT TOOLING J) MANUFACTURING CAPACITY AND DELIVERY SCHEDULE
Q1) How many bolts have Pilgrim International supplied to date? A1) The Pilgrim Radial Fit Bolts were first supplied in 1987. Over 20,000 Pilgrim Radial Fit Bolts are in service worldwide in both the Power Generation and Marine Industries. Q2) Approximately how many units have Pilgrim supplied for both 50HZ or 60HZ rated turbine machines? A2) Many Pilgrim Radial Fit Bolts have been supplied for use both on 50HZ and 60HZ rated machines. These would include Nuclear, Hydro Electric and Fossil Plants in USA, Canada, Korea, Taiwan, UK - for Westinghouse, GE, Alstom, Hitachi, MHI, MAN, Parsons, Siemens and Toshiba machines. PILGRIM Radial Fit Bolts have also been supplied to for use on a number of Siemens and MHI Gas Turbines. Q3) Have Pilgrim had any problems with the Radial Fit Bolts, possibly in areas such as sleeve cracking, thread failure of the puller or difficulty with the separation of the bolt and sleeve, in the products history? A3) Pilgrim have never experienced any kind of cracking problems with the sleeve or any other part of the assembly. We have never experienced thread failure of the puller. The puller is manufactured from high quality alloy steel and is heat- treated for optimum strength. There are a minority of examples, were we have experienced occasional problems in separating the Bolt and Sleeve. These instances resulted from incorrect clearance between the sleeve and the hole, or poor hole preparation prior to bolt installation. None of these cases were as a direct result of Pilgrim's product design or manufacturing procedure. In such cases Pilgrim International's technical assistance proved invaluable in identifying the cause and resolution of these issues. On these occasions, the bolt still can be removed quickly and efficiently by utilising the alternative method of separation using the bolt tensioning equipment. Q4) How many Bolts does Pilgrim make in a month on average? A4) During the year 1999, Pilgrim's average monthly output of bolts was approximately 188. Q5) How many bolts does Pilgrim make in a month on average at present? A5) At present our average monthly output of bolts is approximately 200. B) FEATURES OF PILGRIM RADIAL FIT BOLT: Design based features Q6) When Pilgrim carry out the bolt design for a 60HZ rated machine, what are the important factors in order to get a reliable design? How is the bending stress at bolt neck reduced? How is the centrifugal force of the nut reduced? A6) Pilgrims are aware of the special requirements of a Radial Fit Bolt that is designed specifically for a 60HZ rated machine application. In order to minimise the level of bending stress in the shank of the bolt, the bolt shank is increased to a maximum diameter. The effect of centrifugal force caused by the mass of the nut is also minimised by reducing the size of the nut and machining off redundant areas of the nut. The Pilgrim Radial Fit Bolts can also be manufactured from materials of higher technical strength to compensate for bending stresses. Q7) Which type of thread form do you use, fine pitch or coarse pitch and advise the technical reason? A7) For the Power Generation bolt designs, which use the internal taper thread, Pilgrim use a fine pitch thread. The fine pitch thread gives greater shear strength properties and retains a greater material cross-sectional area in the bolt for lower stresses. Thread forms used on the bolt are fine threads for maximum retained loading. Following tensioning, some relaxation of the bolt occurs as the threads deflect. This deflection is minimised by using carefully selected fine thread forms thus ensuring maximum retained axial load in the bolt. Q8) How is the bolt assembly prepared, and how do Pilgrim maintain a consistency of the coefficient of friction (µ) during installation? A8) The bolt and sleeve are assembled dry. No lubrication should be applied to the nut/bolt thread, as it is not considered necessary for a hydraulic tensioning based procedure. Lubrication of the nut/bolt parts reduces the effective coefficient of friction (µ) between surfaces that Pilgrim's product design calculations have been based upon. This will ultimately cause the initial setting of the sleeve to be compromised resulting in potential removal problems at a later time. Q9) What is the value for the coefficient of friction (µ) that Pilgrim utilise? A9) The coefficient of friction figure of 0.15 is very well recognised in many different industries as a realistic value to use for torque transmission through steel couplings. Although much higher values are often quoted in academic texts, it is unlikely that these actually apply to on-site conditions. The 0.15 value has always been traditionally used and accepted in the marine industry, for the same calculations and it has been fully approved by the classification societies such as Lloyds, RINA and DNV. Q10) What level of stress concentration factor should we consider at bolt neck? A10) The design of the Radial Fit Bolt allows a stress level of 70% of the material yield strength in the bolt shank annulus area when subjected to the applied load. The annulus area is based on the external diameter of the shank and the diameter of the bore at the base of the taper thread. Stress concentration factors are avoided by using radii and chamfers at all changing sections. Q11) Why does Pilgrim use the 'cross design' oil groove for the separation of bolt and sleeve? A11) The 'double helical' or 'cross design' oil grooves were designed to give optimum distribution of oil during the oil injection removal method. The double cross over groove allows the oil to flow in both directions along the bolt optimising its effect as a mechanism for sleeve removal. C) FEATURE OF THE CHAT - COUPLING HOLE ALIGNMENT TOOLING: Design based features Q12) What type of coupling alignment bolt can we use? A12) Pilgrim promote a range of Coupling Hole Alignment Tooling (CHAT) which we were originally commission to design and supply by one of our turbine OEM partners. The CHAT complements the use of Radial Fit Bolts by quickly and accurately achieving alignment prior to bolt installation. Q13) What are the clearances between the Coupling Hole Alignment Tooling (CHAT) alignment sleeve and the coupling hole? A13) The Coupling Hole Alignment Tool (CHAT) has a minimum to maximum diameter range of 2.5 mm. It is usual to design the sleeve to be 1 mm below the nominal design size of the coupling hole at its minimum diameter. Therefore the tool has a potential to expand 1.5 mm above the nominal hole size to allow for hole variations. Q14) What kind of material does Pilgrim use for its components? Please make suggestions as to the reasons for this material selection? A14) The majority of bolts, sleeves and nuts are manufactured from a high quality grade of alloy steel BS970 817M40'T'. This grade of material can be sourced locally to our facility in England and provides the following mechanical properties required for the Pilgrim Radial Fit Bolt design. The material has the following advantages:- - similar in mechanical properties to conventional bolts - excellent availability in the UK - good machineability - high strength material selection if required - similar material properties to most turbine couplings The specification is equivalent to the following standards SNCM 447 ASTM4340 DIN 34CrNiMo6. Q15) What kind of coating is used on the bolt sleeves? A15) The sleeve component is finished with Tufftriding process. Tufftriding is a surface nitriding process that prevents pick-up or galling between the bolt and sleeve. Tufftriding also improves and maintains the consistency of the coefficient of friction (µ) between the bolt and sleeve and improves corrosion resistance. Q16) What kind of parts do Pilgrim recommend to have on-site at the power station as emergency spare parts? A16) The amount of spare parts any one customer wishes to hold varies. However Pilgrim would always recommend the following spare parts as a minimum requirement in case of emergencies:- Coupling Bolts 1 x Radial Fit Bolt assembly of each coupling design 2 x Sleeves of each coupling set Bolt Tensioning Kit Ideally it is advisable to have a complete spare set of the tensioning kit as all the parts are crucial for installation and removal. However the following part is a minimum. 1 x Seal Kit for Hydraulic Head Morpress Pack Air Pump 1 x Complete spare seal kit for pump unit 1 x Hose assembly complete with quick fit connectors Note that Pilgrim can supply spare parts with very short deliveries please contact us directly for further information. Q17) How do we control radial fit bolt weight and tolerance? If for example the bolt weight variation is within 5g, is it possible to adjust the weight of the parts by re-machining? A17). During the initial manufacture by Pilgrim, our components are toleranced to avoid large weight variations. The Radial Fit Bolt assembly (i.e. 1-Bolt, 1-Sleeve and 2-Round Nuts) will be individually weight matched against the batch of existing bolts. The maximum variation would be in accordance with your specification. Each component of an assembly is identified with a number so that the original combination can be maintained. It is not usually necessary to adjust the bolt weights on site but if required we would suggest machining the top face of the round nut. Q18) What is the mechanism to return the hydrualic tensioner piston after tensioning? A18) The piston of the tensioner can easily be returned by hand. This is achieved by turning the hydraulic head with the tommy bar so that it screws down on the puller whilst still connected to the bolt. This action applies a controlled and uniform force to retract the piston. This procedure should be completed after each use of the hydraulic tensioner. Q19) How much tolerance for scratch damage on the coupling bolt holes is allowed and what is the standard for this? A19) Please click here to see our attachment that shows the technical information sheet for flange hole tolerance and surface condition required prior to correct bolt installation. Q20) How much clearance is there needed between radial fit coupling bolt sleeve and coupling bolt hole on the coupling? A20) The outside diameter of the sleeve is machined to a size equal to the measured coupling hole diameter minus the sleeve clearance given by Pilgrim. The clearance is specified in the instruction manual data table supplied with the radial Fit Bolts. Q21) How are the bolt sleeves supplied, are they pre-machined before dispatch or can they be machined at site? If they can be machined on-site what kind of tool is required for machining the bolt sleeves after the final hole dimensions have been measured? A21) The sleeves for the Pilgrim Radial Fit Bolts can be supplied either in a finished machined condition or in a state ready for on site machining. This is entirely at the end users discretion. However as part of the bolt tensioning kit, a mandrel is provided as standard to hold the sleeves during the machining process. A different mandrel is provided for each size of sleeve ordered. Click here for attachment drawing. Q22) How is the radial fit bolts removed from the coupling holes? A22) This is a standard reference procedure used for installing and removing the Pilgrim Radial Fit Bolts. If your power station already has Pilgrim bolts please click here to email us with either your or our previous purchase order numbers. This will allow us to send to you the specific site operational removal data needed. Please do not attempt to remove the Pilgrim Radial Fit Bolts without this data, as doing so may invalidate any prior product warranty or guarantee. Q23) Is there any control of the amount of tightening on the Radial Fit Bolt? A23) The use of Hydraulic Tensioning Tools to apply the axial load to the coupling bolt is a far more accurate method of tensioning than conventional torque tightening. It is therefore widely accepted that the retained load after the hydraulic tensioning can be predicted and relied upon. Pilgrim International can verify retained loads during our test procedure by bolt elongation measurements. If necessary the bolt elongation could be verified on site using a micrometer. Pilgrim can provide taper plugs to fit to the bolts to assist measurement taking. Click here for attachment drawing. Q24) What is the type of oil can be used for the pump or hydraulic tensioner? A24) The Morpress Pack Air Pump is supplied without oil in its tank and will need to be filled before use. The type of oil recommended for use in both this and the hydraulic tensioner is premium grade hydraulic oil having an ISO viscosity grade number ISO VG 32 and Kinematic viscosity limits at 40°C of 28.8 cSt minimum to 35.2 maximum. Examples of this type of oil are :- Shell Tellus V25 Esso Nuto HP32 Q25) Do you have ISO 9001 system? A25) Pilgrim is a quality approved to ISO 9001 company. Q26) When did you get this System Approval? A26) Our original approval dates back to 6th December 1989. Click here to see the QA Certificate. Q27) What kind of test do you carry out before you dispatch your products? A27) All new designs of Pilgrim Radial Fit Bolts go through a fully functional test. Using a special test block that simulates the actual coupling, the sleeves are fully expanded and then the bolts fully tensioned. The oil injection removal procedure is also tested, as is the alternative method of separation using the bolt tensioning removal equipment. The hydraulic components are all fully pressure tested and certified. Additional non-destructive testing (NDT) can be undertaken to meet the individual requirements of customers should they be required. Q28) What is included in the QA System for the bolt manufacture? A28) For each component required to be made, a manufacturing and inspection plan is prepared. The planning controls the issuing of material purchased specifically for the component and all the stages of manufacturing, inspection and testing. Each stage of the planning is signed off when completed. Examples of the QA System can be provided. Q29) Do you have ISO 14001 system? A29) Pilgrim is an environmental approved to ISO 14001 company. Q30) When did you get this System Approval? A30) Our original approval was 1st October 1996. Click here to see the Environmental Certificate. Q31) What is Pilgrim's policy concerning the environment. A31) Pilgrim International shall maintain long-term environmental plans (environmental management programs) which shall be continually adapted to developments, new discoveries and experiences relating to the environment. All operations shall be conducted in a manner that protects the environment, prevents pollution and conserves energy and natural resources. All environmental effects shall be taken into account when business decisions are made. Q32) What machining capability does Pilgrim have? A32) Pilgrim has a wide range of machines and processes specifically available to manufacture this product range covering: Turning, Milling, Boring, Drilling and Grinding. The main equipment list includes:- CNC Lathes (3) Vertical Boring Machine Radial Arm Drills Milling Machines Deep Hole Boring Machine Grinding Machines Engraving Machine J) MANUFACTURING CAPACITY AND DELIVERY SCHEDULE: Q33) What is Pilgrim's manufacturing capacity? A33) Pilgrim has a very flexible manufacturing capacity that can be adapted to meet the needs of our customers. We currently work a one-shift system with additional overtime. There is ample opportunity to strengthen capacity should this be required for large orders. Q34) What is your normal delivery schedule, and shortest delivery schedule in an emergency? A34) The normal preferred delivery schedule is 11-12 weeks, depending on the quantity of bolts required. For small quantities of bolts required quickly, the delivery schedule would typically be 4-6 weeks. For spare parts such as sleeves, small quantities of bolts and bolt tensioning kit parts required in an emergency, the delivery schedule would be approximately 7 days. Note that the above dates are typical, for specific delivery or lead times please contact our sales department directly. K) INSPECTION AND MAINTENANCE: Q35) How often should all the parts be inspected on maintenance? A35). Inspection and Maintenance Coupling Bolts - any maintenance procedures for conventional coupling bolts issued by the turbine OEM should be upheld. The Pilgrim Radial Fit Bolt does not require any maintenance unless a problem is found. Inspection of the bolt and sleeve can only really be carried out if the bolt is removed from the coupling hole. Visual inspection of the bolt sleeve and nut components should include the condition of all threads especially the internal taper threads, Also the condition of the taper surfaces of the bolt and sleeve for any damage as well as the outside diameter of the sleeve. If there is any doubt about the condition of any component further inspection should be carried out or the component should be replaced. Bolt Tensioning Kit - all components of the Tensioning Kit should be inspected well in advance of the intended work on the Radial Fit Bolts. If any parts are missing or damaged then they will need to be replaced. Visual inspection of the Tensioning Kit should include the condition of the threads both internal and external as well as all other surfaces for mechanical damage. It is advisable that a spare seal for the hydraulic head is available during the use of this equipment. Morpress Pack Air Pump - the Air Pump should be checked well in advance of the intended work on the Radial Fit Bolts to confirm it is in good working order. The gauge calibration should be checked prior to use and adjusted as required. The condition of all hoses and connections should be visually checked and replaced as necessary. |
| Terms & Conditions/Disclaimer | Best view 1024 x 768 |
Pilgrim International Ltd. © 2005 |