Appendix - A Specifications for High Temperature Vacuum Brazing Furnace

Transcription

1 Appendix - A Specifications for High Temperature Vacuum Brazing Furnace 0.0 VENDOR SELECTION CRITERIA Vendors must have adequate experience in the design, fabrication and supply of similar vacuum brazing equipments. List of those customers using equipments of similar ratings must be furnished. Any other information which substantiates the capabilities of the vendor should be furnished. An expert committee will review all evidence provided and also open literature to ascertain the capabilities of the vendor. Vendor not meeting above criterion will be rejected. 1.0 GENERAL Horizontal, front loading, external/internal gas quench vacuum brazing furnace for brazing Ti alloys, steels, superalloys, ceramics and cerametalic materials. The furnace shall be designed and manufactured to confirm AMS 2750D/BS 5500 Cat 3 British Pressure Vessel standards. 2.0 TECHNICAL SPECIFICATONS 2.1 Hot zone effective size : 600±10mm wide 600±10mm high 900±15mm deep 2.2 Ultimate vacuum level : torr range or better. 2.3 Operating temperature : 350 C 1370 C 2.4 Ultimate temperature : 1450 C (for short term clean up cycle) 2.5 Temperature uniformity in hot zone : 250 C to 500 C... ±7 C 501 C to 700 C ±5 C 701 C to 1370 C.. ±3 C 2.6 Maximum charge weight : 500 kg 2.7 The furnace should be capable of operating when connected to three phase 415±10%, 50±2 Hz supply. All systems to be designated accordingly to match the voltage level. 2.8 Design of electrical and electronic control circuits and all instrumentation shall be tropicalized. 2.9 Panel air conditioner to maintain the temperature of electrical, electronic control circuits and instrumentations Time Vs temperature characteristics of furnace with the change of maximum 500kg: a. Ramp rate : 12 C per minute rate with a charge of 500kg from room temperature to operating temperature of 1370 C. b. Cooling rate : i. Controlled cooling with heater ON & vacuum pumps ON from 1370 C to 250 C under controlled cooling rate. ii. Natural furnace cooling with heater OFF & vacuum pumps ON from 1370 C to 250 C iii. Cooling with inert gas (GFQ) with heater OFF & vacuum pumps OFF with adjustable gas

2 pressure of (a) 5PSIG, (b) +5 PSIG and (c) +15 PSIG of gas pressure in the hot zone Pump down time : a. Diffusion pump warm up time: min. approx. b. To torr: 20 min. approx. c torr: 2 hr. approx Leak rate (Pressure rise method) shall be less than 5 microns/hour in dry, empty and cold furnace The horizontal vacuum chamber, inclusive of autoclave-type front door, shall be double wall construction with provision for water cooling system. All weldments of the furnace chamber construction shall be tested as per ASME standard construction practice to the acceptance leak rate of less than 5 microns/hour. Test certificate shall be submitted along with the furnace Gas Quenching : Re-circulating inert gas quenching system, external type (working pressure of gas in the hot zone shall be 5PSIG, +5 PSIG and +15 PSIG) 2.15 Heating elements : Heavy duty Lanthanum doped molybdenum (MoLa) cross rolled heating elements capacity to meet ramp rate of 12 C per minute Thermocouples : International standard R type thermocouple Tolerance Class I grade Standard IEC (BS EN ) to be used The vendor shall provide job loading and unloading trolley along with the supply of furnace Small molybdenum wire basket for charging small components shall be provided by the vendor. 3.0 BASIC TECHNICAL REQUIREMENTS 3.1 Vacuum chamber and support structure The chamber, including flanges shall be fabricated in stainless steel material having high temperature and corrosion resistance properties. All stainless steel surfaces exposed to vacuum shall be smooth and clean to reduce outgassing The chamber shall be designed in accordance with AMS 2750D/ BS 5500 Cat 3 British Pressure Vessel Standard/ ASME standard or equivalent A separate port for a feed-through shall be provided for up to twelve work thermocouples to check the temperature at various points in the hot zone as and when required The outer shell shall be primed and then finished with two coats of heatresistant paint. 3.2 Vacuum system Suitable mechanical pump, roots blower, holding pump and diffusion pumps from reputed makes like Strokes/ Leybold/ Edward/ Varian shall be designed and supplied. 3.3 Electrical system and control system PLC logic to control sequential operation of vacuum pumping system (PLC

3 from a reputed make like Allen Bradley, Seimens etc) Mimic diagram to read the vacuum pumping system Proven electronic control circuit to control the temperature of the furnace with in ±3 C of the programmed value (please refer Para 2.5) The controlled power feeding the heating element shall be through a Variable Reactance Transformer/Silicon Control Rectifier (SCR)/ Thyrister control.. The Variable Reactance Transformer shall be of water cooled type All power cables and control cables to be routed through metallic ducts Vendor to supply all the necessary power cables, control cables and compensating cables etc The control panel shall have necessary feed back system to indicate voltage and current drawn by heating elements in different zones Potentiometer to fine tune the power feeding the heating elements so as to achieve temperature uniformity in the hot zone with in ±3 C All thermocouples, compensating cables, connectors and plugs used to measure the temperature shall be of tolerance Class I grade IEC (BS EN )/ ASME or of equivalent standard. 3.4 Gas quenching system Suitable Gas Quench shall be provided with re-circulating inert gas quench system to distribute gas through circumferentially located internal zone for rapid and uniform cooling of the charge. 3.5 Vacuum gauge controller Suitable vacuum gauges and display/ controller from reputed make like Leybold/ Edwards etc to measure the entire range of vacuum shall be profiled. 3.6 Control and temperature instrumentation Furnace temperature controller cum programmer from reputed make like Honeywell to have the following features shall be provided: - Microprocessor based with 3 mode digital controller. - Auto tuning to enhance control strategies. - Superior accuracy (±0.1% typical) and repeatability. - Sixteen event output for process control. - Plug-in memory card to provide minimum 99 program storage. - Each program can contain up to 99 segments. - A clear, user friendly key board. - Three seven segment LED s. - A Two-line LCD display. - A six-segment profile projection etc PC based integrated/ supervisory control system with manual override facility. If the furnace control circuit is designed to operate all the functions on PC based circuit, then adequate provision shall be made to operate the furnace on MANUAL MODE also. This provision is essential to ensure that due to

4 some reason if there happened to be as snag in the PC based circuit, the control to be changed over to Manual Override. Manual Override switch to operate all the sequential operation of the vacuum system, gas fan quenching, furnace temperature control, display of all indicating and control instruments, recording instruments and all safety interlocks for safe operation of the furnace. Data acquisition system to log the heat treatment cycle s parameters such as vacuum, hating cycle, cooling for a period of 22 hours Remote Tele-diagnostic facility to be provided: Tele-diagnostic facility to establish a link between the user and the manufacturer, to study the status of the furnace and to make corrective action for software snags from the manufacturer s end. If the problem is in the hardware, necessary message shall be sent to the user for corrective action Over temperature protection A digital controller from reputed make like Honeywell for over temperature protection, range from 100 C to 1500 C (can be set at any desired level) and compatible for R, S and B type thermocouples shall be provided Data recorder - An alpha-numeric, high speed, microprocessor based recorder. - At least 16 channels for recording temperatures and vacuum levels. - To record at least 13 channel of temperature (thermocouples settable for K, R, S and B type). 4.0 OPTIONAL: CLOSED LOOP COOLING SYSTEM. A self contained water cooling system of adequate capacity to cool the furnace when operated to its maximum temperature on long dwell cycle and also to cool the vacuum pumps, gas fan heat exchanger etc. 5.0 INFRASTRUCTURE AVAILABLE AT DMRL DMRL will provide the following infrastructure: Power supply switch gear, Compressed air and Re-circulating water cooling system. NOTE: The vendor shall specify the requirements for the above in their technical quotes. 6.0 SAFETY, ALARM AND INTERLOCKS. 6.1 All essential safety interlocks such as water pressure, air pressure, grounding of heating elements, furnace over temperature protection for safe operation shall be included in the control circuit. Visual alarms shall be provided to indicate failure or malfunction of critical operations. Acknowledgment circuit for audio alarms to be provided. Failure of critical operations shall require manual resetting before the operation can resume. 6.2 In the event of a power failure, all vacuum valves MUST get closed there by protecting the hot zone, vacuum pumps and the work load from damage. 6.3 Electrical control cabinet shall have emergency switches. 6.4 The overall design of the furnace system shall place an emphasis on safety, userfriendly operation, accessibility of components for maintenance and reliable performance.

5 7.0 ASSEMBLE AND ACCEPTANCE TESTING The entire furnace shall be assembled and tested at manufacturer s work as per vacuum furnace acceptance standards like AMS 2750D/ BS 5500 Cat 3 British Pressure Vessel Standards and all the functional capability of the furnace brought out in the specifications and the same tests shall be repeated at DMRL after installation and commissioning. 8.0 SPARES 8.1 Spares and services : Vendor shall guarantee: a. Availability and supply of spares for a minimum period of 10 years from commissioning of the furnace. b. After sales service to be available for at least 8 years after expiry of warranty, based on annual maintenance contracts or on call basis. 8.2 The vendor shall provide the following spares for two years trouble free operation of the furnace: LEVEL I O rings for the system Thermocouples Pirani Gauge head Penning Gauge head Emergency fuses LEVEL II Heating elements diffusion pump heater diffusion pump oil rotary pump oil Solenoid valves LEVEL III quartz viewing glass pressure relief valve ON/OFF switches indication lamps contactors rotary pump service kit roots pump service kit 2 sets 5 nos 2 nos 2 nos 2 sets 2 nos 10 ltrs 50 lts 1 no 1 no 20 nos 20 nos 8.3 The supplier shall also give a detailed list of spares which are essential and which are not included in 8.2 for both the furnace and control system, segregated as Level- I, Level-II and Level-III spares depending on the probability of failure during two year period of warranty. The list should be comprehensive comprising of mechanical, electrical, electronic, vacuum system and hydraulic spare components listed separately category wise. The supplier should clearly indicate the description, quantity and cost against each spare part in the list, which shall enable the user to select only those spares as required by the user. 9.0 INSTALLATION REQUIREMENTS

6 The supplier shall provide all necessary details such as floor area requirement, foundation drawings, installation drawings and any other special requirements immediately after placement of order DOCUMENTATION Three sets of following documents in English are required to be supplied: a. Programming manual. b. Operator s instruction manual. c. Maintenance and spare parts manual of mechanical, electrical, electronic, vacuum and control systems including bought out items. d. Electric and electronic circuit drawings for control systems and interface for component level trouble shooting. NOTE: of the above at least one set each is required to be supplied with in 3 months of the placement of order, and balance along with the furnace INSTALLATION AND COMMISSIONING Installation, commissioning and testing of the furnace shall be carried out by the manufacturer. DMRL will assist the manufacturer s engineer to install the furnace. The manufacturer shall indicate the requirement of the crane/ forklift and any other requirement to install and bring all the special tools required for installation. 12. WARRANTY The vendor shall provide warranty for a period of 24 months from the date of commissioning and acceptance for the performance of the total equipment supplied. The supplier should ensure continued supply of spares throughout the useful life of the furnace (minimum of 10 years). 13. TRAINING Manufacturer shall train three DMRL engineers at their site, in furnace operation and maintenance. The training should coincide with the inspection of the furnace at the manufacturer s site. The training shall also include those portions of the package, which are bought out from third party. At the time of installation and commissioning at DMRL few more operators and maintenance personal shall be trained. Duration of training at the manufacturer s site: 2 weeks The training shall be free of charge. Cost of travel, boarding and lodging of DMRL engineers will be borne by DMRL AFTER SALES SERVICE After sales service from factory trained and competent service engineers within 48 hours of breakdown call is required Service during the period of warranty shall be free or charge It is the manufacturer s responsibility to upkeep of the furnace and the control system including all the sub systems supplied by third party The supplier shall be prepared to enter into annual maintenance contract after warranty period and shall quote for the same Details of No. of service engineers, spares stocking and address of service center in India shall be provided.

7 15.0 REFERENCES Manufacturer should submit along with their offer a reference list of users of their furnaces. The list should contain the following: Total number of similar furnaces built as on date (of the type/model offered to DMRL) and other details in the format given below: Sl.No. Model & Year of supply Address of customer where the furnace is in use India/ Abroad Address and Contact details 16.0 DELIVERY The vendor shall supply the vacuum brazing furnace along with accessories within a period of 32 weeks from the date of placement of order SPECIFICATION DEVIATION (VERY IMPORTANT) The supplier must provide along with the offer a clause-by-clause statement of deviation/ compliance of the furnace offered as compared to that of the specification PRICE FORMAT The vendor shall quote the price as per the format given below. This is essential to compare different offers. Bids that are not quoted as per the format provided are liable to be rejected. Sl.No. Description Qty. Price Remarks 1. Price for basic furnace as per specification. 2. Price for Level-I, Level-II and Level- III spares. 3. Price for all optional features. 4. If any other item not included in the specification