Centorr High Temperature Vacuum Furnace

Centorr Series 60 Front-Loading High Vacuum

and Controlled Atmosphere Furnace

This Series 60 Front Loading High Vacuum and Controlled Atmosphere Furnace is part of a longstanding C/VI tradition of quality and dependability in high-temperature, controlled atmosphere heating technology. This unit comes with a 30-day warranty and includes one day of test fire and training at our plant in Terryville, CT. We will include the complete, original manual.

The Series 60's cylindrical 11” x 11" hot zone is resistance heated (up to 1400^oC) and is insulated from the cold wall by a layer of graphite insulation.

Access to the hot zone for loading and unloading, as well as for routine maintenance and inspection, is gained through a full-opening front door. Swing clamps are provided to maintain a tight seal when the furnace is operated at slightly positive pressures.

The inside of the furnace chamber conforms to the best high-vacuum practices, with particular attention given to surface finish and choice of materials. The design and construction of high-quality vacuum furnaces calls for minimizing component surface area and potential leaks; thus, you won't find rough interior surfaces, inferior materials, ceramic refractory insulation, or internal coolant connections in this furnace.

Visual observation of the specimen and optical pyrometric monitoring capability are provided by a rotatable gas ported sight window located on the front door of the chamber, in line with the center of the hot zone. Ports are also provided for inert gas inlet, evacuation system, thermocouples, gauges, and other pertinent instrumentation.

Instrumentation is carefully positioned for optimal monitoring and control. Furnace temperature is controlled by a closed-loop circuit between the temperature sensor, the control instrument, and the power supply. The whole system is protected by a water-flow interlock that shuts down the hot zone if cooling water flow is reduced or closed off, and by an over-temperature interlock that shuts the heat zone down if furnace temperature exceed desired setpoint. Components are readily accessible for inspection and maintenance.

This furnace will be ready to operate as soon as connections are made to the proper utilities and a few start-up tests are performed. This furnace will be completely assembled and thoroughly tested before shipment.

Outstanding Features:

Provides clean, efficient, even heating; fast heating and cooling.
Can be used in rough vacuum or controlled inert gas.
Viton elastomer O-ring seals are used throughout the furnace chamber.
Three-mode temperature controller provides accurate temperature control stability from 50°C to maximum rated temperature of 1400°C.
Double-wall, water-jacketed vacuum chamber design eliminates "hot spots" typical in chambers cooled by tubing traces.
Hinged door provides full access to the inside of the furnace for easy loading, cleaning, and other operations. The furnace door is mounted by means of a double-pin hinge assembly; this prevents scuffing of O-rings and permits door to close snugly onto the main chamber flange. Swing clamps are provided to ensure a tight seal during operation with slightly positive pressures; a limit switch interlocked to the power supply will prevent operation if door is open.
A ¼” diameter rotatable gas ported sight window located on the front of the chamber in line with the center of the hot zone - allows for easy visual observation of the specimen.
A graphite retort sits firmly upon the graphite hearth. A dedicated gas system allows gas flow-through of up to four different gases independent of the chamber gas under the proper setup.
A spring-loaded top flange assembly accommodates multiple functions: a survey thermocouple along the vertical centerline of the hot zone, retort gas inlet plumbing and a means of withdrawing the gas inlet tube away from the retort during loading and unloading. A dynamic seal and couplings are provided to maintain the vacuum seal inside the chamber and within the retort gas system.
A gas control system including: a ball valve, a pressure regulator, pressure gauge, and a flow meter for five circuits, one for the chamber and four for retort gases (manifolded together).
Pressure gauges for reading pressure inside the retort and inside the chamber.
Heating element and insulation have long lives, and can be easily removed for cleaning or servicing.
Both operator and equipment are protected by water-flow and over-temperature interlocks.
General appearance is such that the furnace system will compliment any facility.
System is user-engineered for easy operation; techniques can be mastered in just a few hours.

Utility Requirements:

Electrical: 59 kVA 460/3/60, 79 amps
Water: 8 GPM @ 50 psig (30 l/min. @ 3.52 kgs/cm2) and 70°F (21^oC) maximum inlet temperature; pH should not exceed 7.0-7.5; conductivity should not exceed 300-400 micro mho/cm
Gas (inert): 30-50 psig delivery pressure
Compressed air: 60-90 psig (4.2-6-3 kgs/cm2), filtered and lubricated Floor space: 92" (2.33 m) wide x 106" (2.69 m) deep (with door open) Approximate weight: 2,800 Ibs. (1,270.1 kgs.)

Performance:

Maximum operating temperature:

1400°C in argon
1400°C in nitrogen
1400°C in helium
1400°C in 95% nitrogen and 5% helium
1400°C with 90% helium and 10% oxygen in retort

Operating pressure:

2 psig to 20-50 micron vacuum range

Maximum shell temperature of the furnace chamber: 150°F (65.5°C)

WARNING: This furnace is NOT designed to operate with a hydrogen atmosphere. Without special design features, hydrogen operation can be EXTREMELY DANGEROUS! DO NOT ATTEMPT!

Specifications:

Hot zone size: 11" diameter x 11" high {28 cm diameter x 28 cm high); useable size 10" diameter x 10" high (25.4 cm diameter x 25.4 cm high)
Heating element: cylindrical graphite, 3 equal sections
Heat shield: rigid graphite insulation
Work support: 3-pin graphite
Power feed-through s: water-cooled copper
Furnace loading: through full-opening front door
Furnace chamber: 304L stainless steel, double-walled, water-cooled
Pumping port: 1” (2.54 cm) port on rear wall of chamber
Sight port: one ¼” diameter rotatabte gas-ported sight window located on the front of the chamber in line with the center of the hot zone, for visual observation of the specimen
Chamber mounting: open frame with furnace supported in between the two (2) uprights; center of hot zone is 48" (121.9 cm) above the floor

Power Supply: 45 kVA, 460/3/60, 13 volt, 3 phase secondary

The power supply consists of the following:

Main power supply fuses to protect the power supply circuits Main power contactor used to connect power to the SCR controller Isolated stepdown transformer matched to the heat zone load
Silicon controlled rectifier (SCR) power pack and phasing system for continuously modulating power input to the furnace
Magnetic contactors and motor starters for all major electrical components
Water flow interlock - there are two (2) flow switches provided as part of this interlock system. The first is positioned after the heater jacket circuits. The second is wired in series with the first and is positioned after all of the water (cooling) circuits. If water flow falls below a predetermined level through either of the flow switches, the heat zone power will automatically shut down.
Set of water-cooled cables to connect furnace feed-throughs to the secondary of the power transformer
Amp and volt meters, for monitoring the power supply
Emergency power off- an emergency power off pushbutton, when actuated, completely removes all power from the furnace system.

Control Instrumentation:

The control console provides panel space for all operating controls, indicating meters, and instrumentation, and gas controls (the power supply is enclosed in the base of the console).
Sensors: Type "C" W5%Re/W26%Re thermocouples with moly sheath and ceramic insulation, 1/8" (3.2 mm) diameter by 10" (254 mm) long, with seal gland located on sides of chamber
Digital Programmable Controller: Yokogawa UP550 digital programmable temperature controller with 30 programs and 300 segments with .1^o resolution (three-year manufacturer’s warranty)

Yokogawa Light Loader

Over-Temperature Controller: Honeywell UDC 2000 over-temperature controller
Survey Thermocouple Display: Honeywell UDC 2000I digital indicator
Vacuum Gauge Controller: Granville-Phillips 275

Accessory Equipment:

Evacuation system "D6A3"
The evacuation system consists of mechanical vacuum pump, manifold, valves, and filter; valves are normally closed, and they will automatically close upon loss of power. This system is used primarily to evacuate the furnace chamber prior to backfilling with an inert gas.
The evacuation system is located immediately adjacent to the furnace chamber for maximum efficiency.
Components:

Mechanical (roughing) pump: Leybold D25B (20.0 CFM)
Oil mist eliminator: Massvac 360300
Roughing valve: Electro-pneumatically operated Inert Gas Kit (backfill)

Inert Gas Kit (backfill):

For inert gas operation, a number of subsystems exist within the inert gas system. There are two main systems; the chamber and the retort. Under the chamber, there are two systems; backfill and partial pressure. Backfill allows refill of inert gas into the chamber up lo the pressure of the relief valve on the chamber. Pressure can be read from the gauge mounted on the chamber or on the gauge on the control panel. Partial pressure is a function which combines the action of the pump with the inlet valve of the gas. Therefore, a pressure less than atmospheric can be maintained in the chamber. Partial pressure is available only when the furnace is being run without a retort. For the retort use, there are tubes to feed into and return gas from the retort, separate from the chamber gas systems. Pressure in the retort is read off the gauge on the front of the control panel. When operating property, the retort will exhibit a pressure slightly less than that of the chamber. This will ensure that retort gases will not escape into the chamber, avoiding the potential of harming the graphite hot zone. As designed, with the pressure differential active, a flow-thru condition exists through the retort. This means gas will be flowing out of the retort relief valve. This flow should be directed toward an exhaust device, a scrubber, or addressed in some other responsible manner. The chamber gas inlet can accept one gas; the retort can accept up to four inlet gases. All gases must be inert inside the chamber. The retort can accept a gas or gas mixture with a maximum content of 10% oxygen. Each of these five inlet lines have a manually controlled pressure regulator (and gauge} and flow meter. Tests have shown that the higher the flow, the greater the pressure difference, but a minimal pressure difference is all that is required. All of the valves are equipped with solenoids for electronic operation.

WARNING: This furnace is NOT designed to operate with a hydrogen atmosphere. Without special design features, hydrogen operation can be EXTREMELY DANGEROUS! DO NOT ATTEMPT!

Used