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Gemlab Box-Muffle Combo Furnace Model BV50-1200

Gemlab's model BV50-1200 is a feather-weight, desktop furnace occupying minimum work space and it is the most economical furnace designed by Ted Themelis. This furnace employs unparallel versatility and impeccable design of its class not found anywhere in the industry. Depending on the configuration mode the furnace can be used as classic box furnace or with a vertical top-loaded alumnina muffle. tube. Any gemstone may be loaded and heat-treated for days, weeks or months in air, oxidizing, nitrogen controllable atmosphere with or without chemicals additives; also the gemstone may be heated in vacuum.


Model BV50-1200 with the
vertical muffle 50 mm tube

Direct gas purge mode - Vaccum mode
In this mode the gemstones are loaded from the top opening of an alumina Close One End tube and hermetically sealed with the 3-pc set flange. Under this configuration, oxygen or nitrogen can be directly purged into the muffle via the gas purge assembly at any temperature to 1200oC and directed out of the heat treating room via an exhaust assembly. Chemical additives may or may not be used. Vacuum can be applied instead of gas purging for selected heating applications. In this mode, one crucible OD=40mm L=100 mm is used holding about 1250-1300 carats of gemstones.

Feature & standard equipment

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Bench-top, only 250 (D) x 250 (W) x 350 (H) mm
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Feather-weight, only 15 kgs
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Oper. temp. 1100oC (continuous); 1150oC (short time)
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Double steel shell design ensures outside furnace skin temperature below 60oC (EN661010 safety standard)
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Cooling fans ensuring continuous ventilation
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Single gas inlet port allows single gas purge assembly including a flowmeter, pressure gauge, on-off valve..
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Vertical tube, top loading/unloading muffle attachment provides direct gas purging of gas using single-flow meter air, oxygen, oxygen-nitrogen, or vacuum operation to maximum 1150oC..
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Aluminium 3-pc set flange assembly for sealing hermetically one end of the alumina muffle
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All alumina ceramics (99.5% pure): 1 pc. Close One End muffle tube, 1 pc. straight crucible, 6 pcs dishes, 1 pc disk; spacer
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Vacuum system: 2-stage pump, gauge, fittings, hose
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Thermocouple"K-type" assembly with t/ce extension wire
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Artificial Intellegent auto temperature programmer controller
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SSR (Solid State Rectifier) Controller & Trigger
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High quality Kanthal wire A1 heater.
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1500-grade hot face with excellent temperature uniformity
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Controls: Lighted ON-OFF switch, heater ON-OFF switch, heater indicator, buzzer-alarm.
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Plugs to any 220Vac-10A single-phase electric outlet

 

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Model BV50-1200 without the muffle tube can be used as a box furnacel

Front-door heating-no muffle, no gas purging
Model BV50-1200 is suitable for many heating applications where gemstones may be heated with/without additives. No gas purging in this mode. The gemstones may loaded into the heating chambers equipped with locking latch. The heating chamber can accomodate as many crucibles can fit in the heating chambers 100x100x100 mm with maximum loading capacity of about 4,400 carats. Chemical additives may or may not be used. Vacuum cannot be used in this mode.

Glipses and features of model BV50-1200 combo

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Model BV50-1200 at soaking temp. 1100oC in vacuum. Vacuum gauges shows about 25" Hg. The temperature at the ceramic tube is about 220oC, below the maximum safety temperature of 300oC

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Model BV50-1200 during the testing shows PV=1000oC which is in agreement with SV=1000oC without any temperature tolerance. The amperage is about 3 A @ 220 Vac or indicating that 720 are required to produce and maintian heat at 1000oC.

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Model BV50-1200 shows the vertical muffle tube tube; the muffle is sealed with a flange assembly; port-IN and port-OUT and thermocouple is also shown. The heating wire is embedded in the hot face of he furnace insulated with 1500-grade refractory material.

Consumables and life expectancy of the parts BV50-1200 combo

ELECTRICITY

Electricity consumption depends on many factors. On a typical heating process the furnace requires about 700 Watts to maintain 1200oC furnace soaking temperature for several hours.

MUFFLE TUBE

A typical muffle tube lasts usually more than 30 heating runs if properly sealed at soaking furnace temperature about 1200oC in air; life expectancy is reduced proportionally as the furnace temperature is increased; about 20 runs in vacuum at soaking 1200oC for 2 hours
CRUCIBLE AND OTHER TECHNICAL CERAMICS The life expectancy of technical ceramics (crucibles, disk, dish) depends on many factors (heating up rate, cooling down rate, soaking temperature, time are soaking temperature, type of fluxes and other additives is used. Technical ceramics usually last 10+ runs at soaking 1200oC for several hours; less if fluxes are used in the heating process.
THERMOCOUPLE K-type thermocouple assembly lasts over 300+ runs at 1200oC furnace operating temperature.
HEATING ELEMENTS The life expectancy of the heating wire depends on many factors which should be carefully considered. No guarantee is made by any heating wire manufacturer. The heater wire cannot be replaced as it is embedded in the ceramic insulation. If the life expectasncy of the heater is consumed, then the heater module should be replaced. Life expecatancy of the wire is more than 5,000 of hours of operation at 1200oC.

Technical specifications Comparison features between all Gemlab models

 

 

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