15-tube reducing furnace is mainly used for reduction from tungsten oxide to tungsten powder. The equipment is fully automatic. 

Technical specification

Type	GN15R(A)
Dimensions of pipes	124 mm (ID) 140 mm (OD)*13800 mm (L)
Length of heating zone	7390 mm
Length of cooling zone	3295 mm
Weight of furnace	≈35T
Outside dimension	19407×5400×3368 mm
Heating power	460KW
Power supply	380 V three-phase A.C., 50 Hz
Max. working temperature	1050℃
Number of trays in furnace	27*15 pieces
Dimensions of double trays	Upside: 466*91*36 mm Downside: 500*95*60 mm
Flow rate of inlet H2	Max. 900 Nm3/h
H2 inlet pressure	0.03-0.08 bar Adjustable)
N2 inlet pressure	3 bar
Compressed air inlet pressure	6 bar
Dew point of H2	-60℃
Temperature uniformity	Temperature variation for the same point ≤±5℃ Temperature variation of 15 tubes on the same cross section ≤±15℃

Structure and their function

Furnace body

• Furnace steel box: It is welded by five Q235 steel plates and used for installing furnace tubes, thermal insulation, heaters, and temperature measuring device.
• Furnace frame: It is welded by 10# square steel tubes and used for supporting the furnace body and tubes.
• Thermal insulation: The insulation is composed of insulation materials and firebricks. Insulation materials include: alumina fiber blanket, alumina fiber multi-layer blocks, ceramic fiber boards, and calcium silicate boards. Firebricks include: light alumina bricks, high-density alumina bricks, special bricks for heaters, and silicon carbide plates.

Furnace tubes

15 furnace tubes

Trays:

• 450 sets of double trays
• Material of the trays：0Cr28Ni48W5

Heating and temperature control system

• 6 heating zones
• Heating material：0Cr27Ai7Mo
• 3 thermocouples per heating zone (Each in upside, middle, and downside)

Automatic system

• Trays inlet: Trays are transferred to the front of the furnace through chain wheels. Then trays inlet system, which is driven by servo motor, takes the trays to inlet position of each furnace tube. After trays are pushed into furnace tubes by pneumatic cylinder, tube doors close.
• Trays outlet: When back door of a furnace tube opens, trays outlet system, which is driven by servo motor, will pull the trays out and take trays to unloading system.
• Trays separating: In unloading system double trays will be separated by mechanical arm.
• First unloading: Trays are pushed to first unloading position, then fixed by clamping pneumatic cylinder and turned over by rotary pneumatic cylinder to unload.
• N2 protection: In order to protect the material from the air after getting out of the furnace, two N2 pipes are installed in trays outlet system for blowing N2 towards trays. A transparent cover with N2 filling in is installed for unloading system till the first unloading position. Automatic doors are used at entrance and exit position of the cover.
• Trays cleaning: After first unloading, trays are pushed to cleaning position and cleaned by metal brush, which is driven by serve motors.
• Second unloading: After cleaning, trays are turned over again for second unloading at the second unloading position.
• Loading: Trays are pushed to loading position by pneumatic cylinder. When system detects trays, electronic scale starts automatically, then weighs and loads according to preset weight.
• Evening: Trays are pushed to evening position by pneumatic cylinder. Evening device moves through pneumatic cylinder.
• Trays laying: Filled trays are taken to laying position and then mechanical arm lay the upper tray onto the under tray.

Electric control system

• Siemens S7-300 PLC for working process control (including temperature, flow-rate of process gases, etc.)
• Fifteen glass rotary flow meters
• Solenoid valve for pushing pneumatic cylinder and furnace doors opening and closing
• Visualization-PC system: IPC (Industrial Personal Computer) supplied by Siemens
• Language: Chinese and English

Gas system

Gas control panel: Each of H2 and N2 has an individual main pipe. Process gases are measured by glass rotary flow meter and controlled by solenoid valves.

Main suppliers

Electric part

Circuit breakers	Schneider
Miniature circuit breakers
Contactors
Relays
Control push button
Control switch
LED indicator
Power supplies
Motor circuit breakers
Emergency-off pushbutton
Servo motor
Control cabinet, panels	Chinese suppliers
Terminal boxes
Cable
Limit Switches
Control transformer
Fuses and fuse links	Wohner
Interposing relays	Phoenix Contact
Proximity switches	Turck
Electric motors & decelerator	SEW
Thyristor controller	AEG
PLCs	Siemens S7 type300 with ET200M
Operator panels, PC	Siemens
Pressure sensors	E+H
Glass rotary flow meter	Chinese supplier
Alarm beacons	American supplier

Mechanical part:

Lead screws, sliding blocks, rails	Chinese supplier
Trays (Cr28Ni48W5)
Heaters (0Cr27Ai7Mo)
Furnace tubes (Cr28Ni48W5)
Insulation materials, firebricks
Pneumatic elements (control&execute)	Rexroth

Note: Grand New has patent of the pushing cylinder, thus the supplier and drawings are not available.

Period of warranty

The warranty is valid for 12 months after the signing date of final acceptance protocol. This guarantee covers the replacement of defective parts only.

This guarantee shall be void if:

• Equipment is not installed and used in accordance with GN’s instructions.
• Any repairs or alterations are made to the equipment by anyone other than a duly authorized representative of GN, or, replacement parts other than GN supplied or recommended are used.
• Any failure is due to misuse of the equipment.

The guarantee does not cover damages resulting from normal wear, corrosion, or improper maintenance. The guarantee does not cover easily damaged parts. For products from sub-suppliers, guarantees shall not in any case exceed the implied guarantees of the sub-suppliers.

• Technical documentation
  To ensure safe operation and proper maintenance of the equipment, the scope of delivery also includes the following documents in 2 copies, both in Chinese and English.

• Installation drawings
• Process diagrams
• Spare parts list
• Wiring diagram
• PLC-program
• Operation guidance
• - Instruction

• Definition of the delivery scope

Scope of delivery:

• The whole reducing furnace;
• A whole automatic system
• A whole set of double trays
• Following spare parts shipped with the equipment:

Parts	QTY	Supplier
Heater	3	Chinese supplier
Alumina fiber multi-layer block	1
Fluororubber gasket (OD170*10)	3
Fluororubber gasket (OD160*10)	3
Flange seal ring	15
Anti-slip rubber blanket	4
Limit Switch	4
Inductive switch	4	AirTAC
Thyristor controller	1	AEG
Proximity switches	2	Turck
Tool case	1

Not included in the delivery scope of the Seller and to be prepared by the Buyer before start of installation works:

• Power supply up to the connection terminals in the power cabinet;
• UPS power supply
• Any supply lines for cooling water, compressed air, and other process gases up to connecting points of the equipment;
• Layout for the foundation of the furnace and of the ceilings;
• Operating-media/ process materials for tests and run;