HB29

HB Series Bench Mounted General Purpose 2200°F (1200°C) Electric Box Furnaces

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LOCKED BY SERIES
Type Bench
Power Source Electric
Loading Front
Uniformity AMS Class 5 (± 25ºF / 14ºC)
Atmosphere
Lining Brick

Applications

LOCKED BY SERIES

Description

The HB Bench furnaces are good general purpose bench mounted box furnaces. The door is an easy to operate spring loaded vertical plug door. Elements are located on the sides. They feature a digital PID tuning control for automatic temperature control. They reach 2200°F (1200°C) with the iron-aluminum-chrome elements or 2100°F (1150°C) with the optional nickel-chrome elements. Many options are available such as special hearths, inert atmosphere operation, stands, and special controls and recorders.


Processes


Markets

Specifications

Dimension
W
H
D
Inside
12
8
24
External
45
38
40
Hearth
11
-
22
Work Cubic Feet 1
* All dimensions in inches unless otherwise specified.
Power
Standard Pwr 8
High Power 12
Max Temp (°F) 2200
Element # 4
* All power values in KW unless otherwise specified.
Weight
Ship Weight 400
Max Load 150
* All weights in Lbs unless otherwise specified.


Additional Features

SPRING LOADED VERTICAL PLUG DOOR
The furnace door is a spring loaded swing up vertical door. The spring holds the door tightly closed, counterbalances it while opening, and holds it up while open. The hot face of the door is kept from the operator. There is a 1/2” refractory plug which protrudes into the furnace chamber and provides an effective heat lock. There is a 2” refractory to refractory seal around the perimeter of the door. Pneumatically operated vertical doors are optional.
CERAMIC HEARTH INCLUDED
The standard hearth is a 3/4” thick ceramic plate elevated on ceramic standoffs 1/2" above the bottom firebrick. This air space aids uniformity.
DIGITAL PID CONTROL SYSTEM
The standard control is a Honeywell UDC 2500 digital PID 3 mode tuning control. All fuses, transformers, contactors, and controls are located in a NEMA 1 panel. Mechanical power contactors are standard; solid state contactors and SCR power controls are optional. The thermocouple is Type K. Thermocouple break protection is included. Limit switches shut off furnace power if the door is opened or the power panel back is removed. Control voltage is 120 volts. A NEMA 13 lighted On/Off switch is included. The control circuit and each power branch circuit are fully fused. Customer must connect fused power supply to single point on panel.
FURNACE UNIFORMITY
The temperature uniformity inside approximately 2/3 of the furnace chamber is in the range of +/-25F (+/-13C) at 1800oF (975C).
TESTING AND INSTRUCTIONS
The furnace is power tested to insure proper watt ratings. The controls are fully calibrated and the control system completely tested. A complete instruction manual includes easy start up instructions, theory of operation, maintenance instructions, parts list, general dimension drawing, general assembly and subassembly drawings where required, and a detailed trouble shooting guide. A ladder logic diagram and panel layout are prepared on CAD for easy readability.
WARRANTY
The furnace is warranted for one year except for elements and thermocouples which are warranted for six months. See warranty sheet Q12W.
FAST HEAT UP:
Heats up to 2100 Deg F in less than one hour at 240 volts, less than 2-1/2 hours at 208 volts.
EFFICIENT MULTILAYERED INSULATION
The furnace is insulated with 2-1/2” of low K factor refractory firebrick as the primary insulation. This is backed up by 2” of very low K factor mineral wool board on all surfaces except the bottom which has 2” of hard calcium silicate back up for solid hearth support. This yields an excellent combination of strength, insulating quality and fast heat up and cool down time. All refractory is coated with a special facing that prolongs firebrick life and helps prevent spalling and dusting. The refractory sections are available completely shaped for easy replacement without cementing. All sections fit together with engineered heat locks which improve the insulating integrity of the furnace. No asbestos is used.
HEATING ELEMENTS AND CERAMIC ELEMENT HOLDERS
Standard elements are coiled iron-aluminum-chrome alloy. The elements are supported in element plates along the sides. These provide perfect support for the coiled element as well as excellent radiating characteristics. The smooth surface prevents premature failure of the element as it expands and contracts. Nickel-chrome elements are optional.
HEAVY DUTY BENCH MOUNTED CASE
The furnace case is constructed of 10, 14 and 16 gauge steel with stiffeners. The entire case is primed with 800F silicone paint and finished in machine enamel. Lifting rings are provided.

Additional Options

ALLOY HEARTHS
Lower temperature furnaces are available with fabricated alloy hearths. These have welded sides (normally 1" high) and reinforced bottoms. 304, 330 and Inconel 601 series stainless steels are commonly used.
ANGLE IRON FLOOR STAND
Hearth level is approximately 32” from floor with this stand.
CONTROL, RECORDER AND ELECTRICAL OPTIONS
CONTROL, RECORDER AND ELECTRICAL OPTIONS
HIGH K.W.
See specifications for amount.
INERT GAS PANEL
The furnace case is tightly sealed for use with a protective inert atmosphere. Argon, nitrogen and gases enriched with up to 4% combustible gas (such as hydrogen or propane) can be used. No safety systems are required. A threaded alloy fitting introduces the gas into the furnace chamber. The element connection chamber is typically purged. The door seal is augmented with a woven ceramic fiber gasket. A properly sized flowmeter/regulator is included with the atmosphere system. A rule of thumb on atmosphere usage is to figure six to ten times the furnace volume times the number of hours the work will be in the furnace.
JIC CONTROL OPTION
This includes a NEMA 12 control cabinet, all oil tight switches and a panel mounted fused disconnect switch. Zone switches if included are percentage timers.
OVERTEMPERATURE SYSTEM
Honeywell UDC 1200 digital high limit back up control with manual reset, back up contactors and separate thermocouple.
SILICON CARBIDE HEARTHS - BENCH AND SMALL DUAL CHAMBER FURNACES
The optional hearths feature molded sides and are 1" thick.Silicon carbide features high strength at high temperatures, a non warping flat surface, and excellent heat transfer (which is important if there are elements under the hearth).
SINGLE ZONE SCR POWER CONTROLLER
A zero fired SCR power control with two-leg control is used instead of contactors. This is constructed with transient voltage protection, sub-cycle fuse protection, extra large heat sinks, and positive zero firing. Gain and bias adjustments are included for tuning.
SOLID STATE CONTACTOR(S)
For faster cycle times, longer contactor life, and quieter operation

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Brochure For HB