Materials Research Furnaces, Inc

 

    

 

  3000C Graphite Furnace

 

General Specifications
  • Top loading with pneumatic cover lift
  • Graphite zone
  • 20 x 16 diameter element with a usable zone of 18" dia. x 14" high (457mm x 355mm)
  • Available in smaller sizes
  • 3000C maximum temperature in Argon, 2200C in 0.01 Torr vacuum
  • Pyrometer & Retractable Thermocouple
3000C Graphite Furnace

A 3000C furnace with a near 2 cubic foot work area will satisfy all your ultra high temperature requirements. Operation in vacuum is possible but the maximum temperature is limited to 2200C at 0.01 Torr to maximize lifetime of the heating element and shields. Operation is facilitated with the pneumatic chamber cover lift for easy load access and a retracting temperature thermocouple that will retract automatically and switch over control to a pyrometer at a pre-set temperature setpoint. Applications include: sintering, carbon fiber processing, ceramic firing, degassing, heat treating.

Major parts:

  1. Chamber and hot zone
  2. Evacuation system
  3. Gas system
  4. Power supply
  5. Controls
  6. Data acquisition system
  7. Water cooling system
  8. Utilities

 

1. Chamber and hot zone :

The furnace chamber is round and is supplied with a pneumatic top lid that holds all top shielding to facilitate loading and unloading. The chamber is double-walled, manufactured from 304L grade stainless steel and is welded together by the heli-arc method. The chamber is electropolished for a clean, shiny and durable finish. The top cover is attached to the pneumatic lifting assembly for easy, full access to the hot zone. In our graphite type zones, we utilize fibrous graphite insulation. A resistance heated graphite heating element surrounds the work area. Power to this element is delivered through a set of six unique tapered graphite pins that requires no threaded connections. This reduces down time for element replacement. The element zone area measures 20" x 16" with a usable zone 18" dia. x 14" high (457mm x 355mm). The usable area has a temperature uniformity of +/-10oC. A 5/8 diameter rotatable gas ported quartz sight window is located on the front of the chamber.
The chamber has a 4" pumping port on the back side to accommodate an optional high vacuum system. The bottom of the chamber houses ports for the adjustable power feed throughs. The furnace chamber is mounted on a structural, mild steel angle frame, which will house the evacuation system and associated electrical components. The water and gas manifolds will also be mounted to this frame. The control console is located to the right side of the furnace.
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2. Evacuation System:

The roughing pumping system offered will evacuate the furnace to the 20-100 milliTorr vacuum level. This is accomplished with the use of a 38 C.F.M. (1075 lpm) Rotary Vane Pump. An electro-pneumatic vacuum valve is provided to isolate the chamber for operation in gas. A manual pressure relief valve is provided for leak checking the system . Vacuum levels can be monitored by visually observing the vacuum compound gauge or the Vacuum Gauge Controller. The vacuum system is operated by means of a graphical panel. The 4" port on the chamber will accommodate an optional high vacuum system.

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3. Power Supply:

Hot zone power is supplied by a three Phase SCR Controlled transformer. This Power Supply is designed to accommodate a ramp rate of 100 C/minute, and Operating Temperature of 3000oC. All circuit breakers, contactors and power controls are housed in one cabinet together with the instrumentation.

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4. Process Gas System:

This furnace system was designed to provide a positive inert gas environment for your work samples. The standard positive pressure used in this furnace is 2 P.S.I.G. An adjustable relief valve and a compound gauge (30 P.S.I.G. x 30 in. Hg.) are located on the top of the furnace body. The inlet gas flow is regulated by means of a valve mounted on a flow meter, and a solenoid gas inlet valve.

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5. Control System:

Temperature control is established with a Eurotherm controller reading a two Color Optical Pyrometer and a type "C" Thermocouple and controlling an automatic TC remover. This retractable TC is sealed with metal vacuum tight bellows, eliminating the need for sliding seals. The TC will control the zone temperature from room to 1500 C. The pyrometer will then read temperature from 1500C to 3000C. At the change-over the thermocouple will automatically be retracted into the shielding, protecting it from over-heating.

The vacuum gauge and controller with a pneumatic vacuum valve and control panel instruments allow monitoring and operation of the vacuum system.

The operation of the furnace is made simple and requires only minimal operator interaction, but still allow supervisors or technical personnel to re-configure and further customize the furnace operation.

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6. Optional DAQ/ HMI System :

As with any of our furnace system, our HMI control system with a user friendly operator interface is available as an option. This package has the added advantage that furnace data is stored, alarms are displayed/recorded, security is added to keep operators from entring unauthorized parameters, and the furnace PC can be networked. Fully automated runs are programmable as well. Classic temperarture and vacuum controllers with push-buttons and switches are the standard operating method.

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7. Furnace Water Cooling Manifold:

The closed drain water manifold provided with this system is designed to adequately cool the furnace and power cables. A water flow switch is installed with a light for visual indication and interlocking the hot zone power. The water manifold has several circuits supplying water to the various parts of the furnace. Each one of these can be manually adjusted to allow each circuit just the proper amount of flow to save water and allow a drain temperature of approximately 100 F.

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8.UTILITIES:

 

POWER 130 kVA, 480 V/3Ph/60-Hz (other voltages available)
WATER 34 G.P.M.(130 LPM) @ 68 F and 50-60 P.S.I.G.
PROCESS GAS AR, 30 LPM. @ 30 P.S.I.G.
COMPRESSED AIR 60-80 PSIG

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