BENCHTOP LABORATORY MUFFLE FURNACE

STANDARD LABORATORY MUFFLE FURNACE MODEL

• PRODUCT FEATURES: all models are made of 14 ga steel (green enamel finish).
• QUALITY INSULATION: low-density refractory bricks, 4½” thick 2,300°F rated.
• LONG SERVICE LIFE & EASE OF MAINTENANCE grooved bricks optimize heat transfer and make maintenance much easier. FeCrAl heating elements are located into the groove of the bricks (but not moulded into the brick) and can be replaced without taking any bricks out. By being in the brick groove, radiant heat from the element is lowered, which offers a better temperature uniformity. The elements are protected from any contact that can occur during the furnace loading. This kind of design also allows the operator to replace just a few bricks when required.
• ACCURATE TEMPERATURE CONTROL: standard controller used is Watlow model PM6 (1/16 DIN) (Single set point controller). Base unit for simple applications. Just input you’re work temperature and let the Watlow EZ-Zone PM6 do its job with its precise PID control feedback loop. This unit also includes built in high limit (HL) overheat protection. HL is easy to program and reset.
• HORIZONTAL OPENING DOOR: heavily hinged door with a 180° opening. We offer a rugged industrial door design.
• FURNACE CHAMBER HEARTH PLATE: all furnaces come with a Cordierite hearth plate.

MODEL POWER OUTPUT

• “HP” MODELS: ramp up time is faster than standard models (see brochure for time Vs. Temperature curves). The “HP” version is especially appropriate when ordering the slide gate chimney option described below.

OPTIONS

Controls & Instruments

• PROGRAMMABLE TEMPERATURE CONTROLLER (4P/10S): Basically the same unit as the single set point unit but with programmable Capabilities. You have four (4) programs with 10 segments per program for a total of 40 segments. You can program your ramp-ups, soak and ramp down time temperature. This system permits you to have defined programs linked to your processes and treatment necessities. This unit also includes built in high limit (HL) overheat protection. HL is easy to program and reset.
• USB COMMUNICATION: This add-on USB port links up to your programmable temperature controller. By using you’re the freeware provided by Watlow and a laptop permits you to quickly modify or set recipes and change desired parameters.
• PROCESS TIMER: This unit paired with standard single set point temperature controller makes the easiest way to use our furnace when dealing with simple process requirements. Just set quantity and desired units, countdown will start when set temperature is obtained giving you consistent soak times. After soak time is finished unit shuts down and awaits next command from operator.
• 7-DAY TIMER: This option permits you to have the furnaces start automatically at defined time. Perfect to pre-heat furnace.
• SSR: This electronic part increases control accuracy in soaking and is much quieter than the mechanical contactors. Makes for a more sturdy electrical system because you don’t cycle contactor.
• TEMPERATURE CONTROLER/RECORDER: Info to come
• PAPER CHART RECORDER: Info to come

Furnace Door

• VERTICAL OPENING DOOR: counter weighted vertical opening door offered on all models. Makes loading parts in furnace easier and safer. Both hands can be used to handle parts.
• HEATING ELEMENTS IN DOOR: Elements in the door are available for F300 and F400 models only. Customers will need this option usually for burn-off applications or to prevent condensation on the door. Can also help in lower temperature uniformity (around 1100°F).
• DOOR SAFETY SWITCH: automatically shuts off the power to the elements as door is opened and restores it as door is closed. Prevent accidental electrical socks if operator touches live element with metal tongs. This option is also provided with horizontal hinged door with elements in door to prevent accidental scorching.

OTHER OPTIONS

• ADJUSTABLE EXHAUST VENT: it’s a slide gate on top of the furnace in case corrosive vapours have to be vented. When this option is selected, a peephole is included.
• NiCr HEATING ELEMENTS: at no extra charge. These elements are usually used for corrosive applications, in Nitrogen atmospheres and for Dental Lab applications.
• CORRUGATED HEARTH PLATE: This hearth plate is corrugated permitting you to complete lost wax process thus letting melted wax to be funnelled in the bottom of the furnace.
• SS 304 CASING: This option especially suited for dental laboratories and corrosive applications.
• FURNACE FLOOR STAND: we offer a heavy-duty floor stand. Can be ordered at specific high.
• INERT ATMOSPHERE (OPTION): This option allows you to generate a protective atmosphere in your oven at high temperature. Such type of atmosphere minimizes oxidation of the steel pieces. This option includes the following items:
  • N2 gas panel
  • Pressure regulator – 30ZAA201595680100000
  º flow meter calibrated for nitrogen (N2) with integrated flow control – MAX 9.5 scfm (N2)

MUFFLE FURNACE CHARACTERISTICS

• Cabinet design & construction choice of Enamel coated 16 gauge steel or (304) stainless steel
• Horizontal opening door heavily hinged door With a 180° opening
• Insulation 4½”/11cm pre-grooved refractory bricks (With the exception of the f50, which is 2 ½”)
• Temperature controller microprocessor temperature controller, with auto tuning pid parameter offering ramp/soak program capability
• Heating elements low watt density fecral heating elements
• Furnace chamber hearth plate the furnace comes standard with a cordiorite hearth plate.

FURNACE OPTIONS

• Vertical opening door Counterbalanced guillotine lifting door with “Zero weight positioning”
• Furnace floor stand Heavy-duty furnace stand
• Ni-cr heating elements Special heating elements used in corrosive environment
• Programmable controller 2 programs with 8 segments ramp/soak
• Solid state relay (ssr) For increase temperature accuracy and silent operation
• Adjustable exhaust vent Slide gate located on top of furnace to vent corrosive vapors, also comes with a peephole in door
• High limit controller Automatically shutdown heating elements when maximum temperature is exceeded
• Door safety switch Automatic Shut off heating elements when door is opened
• 3 phase 208-240v Available for the F300/F400
• Heating elements in door Offers greater heat distribution

OPERATING PROCEDURE

The furnace is preheated with a gas flame, gradually raising the temperature to 1600°F. The oil burners are then started and the temperature of the combustion chamber elevated to 2400°F. Preheating requires about ten days.
Charging of metal is started at 2400°F and the production of zinc vapor begins almost at once. Charging is continued at as rapid a rate as possible until a depth of 5½ in. of metal has accumulated in the vaporizing unit.

Conditions which determine the end of the cycle are: The rate of zinc vapor production for economical operation of the furnace, a low zinc content in the residue metal, as tapped from the furnace, and a lead content low enough to meet the requirements of the particular zinc oxide being produced.

The cycle is ended by tapping residue metal from the vaporizing chamber, emptying it as far as possible. This metal is drained through a tap, not shown, into cast iron molds. The temperature of the furnace is held constant while it is being drained.