Overhauling industrial power turbine compressor assemblies
Overview
This standard identifies the competences you need to carry out a complete overhaul of an industrial power turbine compressor assembly, in accordance with approved procedures. The compressor assembly to be overhauled will have been removed from the turbine assembly, and the overhauling activities may take place in a maintenance or manufacturer's workshop.
In carrying out the overhauling operations, you will be required to follow laid-down procedures and to use specific dismantling and rebuilding techniques. The overhauling activities will involve removing all ancillary components and subassemblies, removing the compressor blades, stators, bearings and seals, and stripping the compressor housing of all its components. You will then be required to inspect the components for damage and wear, and to make decisions on which components can be re-used and which will need replacing.
You will then rebuild the compressor assembly, which will involve fitting replacement or overhauled sub-assembly units and the replacement of all damaged, worn and `lifed' components. The overhauling activities will include making all necessary checks and adjustments to ensure that components are correctly replaced, positioned, aligned, adjusted, torque loaded, locked and fastened, and that the correct sealants are used.
Your responsibilities will require you to comply with organisational policy and procedures for the overhauling of the power turbine compressor assembly, and to report any problems with the overhauling activities, or with the tools and equipment used that you cannot personally resolve, or that are outside your permitted authority, to the relevant people. You must ensure that all tools, equipment and materials used in the overhauling activities are removed from the work area on completion of the activities, and that all necessary job/task documentation is completed accurately and legibly. You will be expected to work with a minimum of supervision, taking personal responsibility for your actions and for the quality and accuracy of the work that you carry out.
Your underpinning knowledge will provide a good understanding of your work, and will provide an informed approach to applying appropriate overhauling techniques and procedures to power turbine compressor assemblies. You will understand the dismantling and reassembly methods and procedures used, and their application. You will know how the compressor assembly functions, the purpose of the individual components and associated defects, in adequate depth to provide a sound basis for carrying out the overhauling activities to the required specification. In addition, you will have sufficient knowledge of these components to ensure that they are fit for purpose and meet the specifications, thus providing a sound basis for carrying out the reassembly.
You will understand the safety precautions required when carrying out the overhauling activities associated with power turbine compressor assemblies, especially those for lifting, handling and supporting the equipment being removed and replaced. You will be required to demonstrate safe working practices throughout, and will understand your responsibility for taking the necessary safeguards to protect yourself and others in the workplace.
Performance criteria
You must be able to:
- work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
- follow the relevant overhauling schedules to carry out the required work
- establish the components to be removed and, where appropriate, mark components to aid re-assembly
- ensure that any stored energy or substances are released, safely and correctly
- ensure that all removed components are correctly identified and stored in the correct location
- carry out the overhaul to the agreed level, using the correct tools and techniques
- report any instances where the overhauling activities cannot be fully met, or where there are identified defects outside the planned overhaul schedule
- complete the relevant documentation, in accordance with organisational requirements
- dispose of unwanted components, waste materials and substances, in accordance with safe working practices and approved procedures
- deal promptly and effectively with problems within your control and report those that cannot be solved
Knowledge and Understanding
You need to know and understand:
- how to work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
- the hazards associated with overhauling power turbine compressor assemblies and how to minimise them to reduce any risk
- the importance of wearing protective clothing (PPE) and other appropriate safety equipment during the overhaul
- how to obtain and interpret drawings, specifications, manufacturers' manuals, history/maintenance reports, and other documents needed in the overhauling process
- how to carry out currency/issue checks on the specifications you are working with
- the quality control procedures to be followed during the overhauling operations
- the procedure for obtaining replacement parts, materials and other consumables necessary for the overhaul
- company policy on the repair/replacement of components during the overhauling process
- terminology used in power turbine compressor assemblies
- the basic principles of how the compressor assembly functions, its operating sequence, the working purpose of individual units/components and how they interact
- the extent to which the equipment is to be dismantled for overhaul
- the sequence to be adopted for the dismantling/reassembling of the compressor assembly
- the techniques used to dismantle the power turbine compressor assembly, without damage to the components or surrounding structure
- the need to protect the system integrity by ensuring that exposed components are correctly covered/protected
- how to lift and move large components and assemblies; the methods and equipment used to transport, handle and lift the components during the overhauling activities
- the need to ensure that lifting and handling equipment is within its current certification dates
- methods of checking that components are fit for purpose, how to identify defects and wear characteristics, and the need to replace `lifed' and consumable items
- the uses of measuring equipment
- methods of reassembling the power turbine compressor assembly, using new or previously overhauled components
- how to make adjustments to replaced components/assemblies to ensure that they function correctly
- the various mechanical fasteners that are used, and their method of removal and replacement
- the various types of electrical connectors that are used, methods of unlocking, orientation indicators, and locating and locking in of the connections
- the tools and equipment used in the overhaul activities, and how to check that they are in a safe/usable condition
- the importance of ensuring that all tools are used correctly and within their permitted operating range
- the importance of ensuring that all tools, equipment and components are accounted for and returned to their correct location on completion of the overhauling activities
- the procedure for the safe disposal of waste materials
- the need to complete overhaul documentation and/or reports following the overhauling activity
- the problems that can occur during the overhauling activity, and how they can be overcome
- the extent of your own authority and to whom you should report if you have a problem that you cannot resolve
Scope/range
Scope Performance
- Carry out all of the following during the overhaul of the power turbine compressor assembly:
- obtain and use the appropriate documentation for the overhaul activities
- adhere to procedures or systems in place for risk assessment, personal protective equipment and other relevant safety regulations and procedures to realise a safe system of work
- provide and maintain safe access and working arrangements for the work area
- ensure that the compressor assembly is suitably supported, and that appropriate lifting and handling equipment is available
- carry out the overhauling activities, following good practice/approved procedures
- ensure that components and surrounding structures are maintained free from damage and foreign objects
- return all tools and equipment to the correct location on completion of the activities
- leave the work area in a clean and safe condition on completion of the activities
- Dismantle the power turbine compressor assembly, to include removing all of the following:
- compressor housing
- bearings
- locking devices
- compressor stators
- sub-assemblies
- wire thread inserts
- compressor blades
- seals and gaskets
- pipes and unions
- curvic couplings
- shims and packing
- Carry out all of the following activities on the equipment being overhauled:
- cleaning parts prior to dismantling
- pre-disassembly checks and tests
- releasing stored energy (where applicable)
- draining/removing any remaining fluids
- proof-marking/labelling of components to aid reassembly
- dismantling equipment to unit/sub-assembly level
- dismantling units to component level
- applying protection to openings to prevent entry of contaminating debris
- replacing all damaged or defective sub-assemblies and components
- removing and replacing components having interference fits (such as by expansion, contraction, pressure)
- checking components for wear and serviceability (such as visual, measurement, NDT, use of probes/scopes)
- drilling, reaming and riveting (where appropriate)
- replacing all `lifed' and consumable items (such as seals, bearings, gaskets)
- balancing components (where applicable)
- reassembling the compressor
- setting and adjusting replaced components
- `blue bedding' components
- making mechanical connections
- applying correct lubrication during assembly
- applying gaskets and sealant/adhesives
- electrical bonding of components
- securing components using mechanical fasteners and threaded devices (such as nuts, bolts, circlips, pins)
- tightening fastenings to the required torque
- applying locking and retaining devices (such as circlips, pins, wire locking, lock nuts, stiff nuts, swage nuts)
- Replace/refit a range of compressor assembly components, to include ten of the following:
- compressor housing
- locking devices
- compressor stators
- wire thread inserts
- compressor blades
- pipes and unions
- curvic couplings
- mechanical controls (such as plungers, springs, rollers)
- bearings
- static seals/gaskets
- electrical controls (such as solenoids, motors, switches)
- dynamic seals
- shims and packing
- mechanical securing devices
- other specific components
- Carry out checks and tests on the overhauled equipment, to include all of the following:
- visual inspection for completeness of all operations
- visual inspection for freedom from damage or foreign objects
- applying protection to openings to prevent entry of contaminating debris
- carrying out any `special-to-type' test rig checks
- Overhaul power turbine compressor assemblies in compliance with one of the following:
- BS, ISO or BSEN standards and procedures
- customer standards and requirements
- company standards and procedures
- turbine manufacturer's requirements