How To Select a Furnace

Uses: These models are designed for those users who require automatic temperature controlled furnaces from 250° F to 2000° F (Model C-601) or up to 2250° F (Model C401H)

At A Low Cost: An ideal unit for many of the small jobs found in Tool rooms, Production Shops or Laboratory.

Temperature Control: Auto tuning microprocessor-based controller.

Elements: C-601 chrome nickel wire. C401H-high temperature iron-aluminum wire.

Wiring: furnace is completely wired and equipped with cord ready to plug into a 115 volt outlet. control, relay and wiring connections are enclosed on the base.

General construction: Furnace case of sheet steel is assembled by use of electrical welding and sheet metal screws. The spring counter-balance door rises vertically on lever arrangement keeping the hot face away from operator. The C401H walls and door are constructed of high quality insulating brick backed by 1800° F block insulation. Furnace is finished in heat resistant hammer tone gray.

Safety switch: These models come equipped with a door safety switch. when door is opened, power is disconnected from the heating elements.

How To Select a Furnace

Uses: These furnaces are designed for general use in the shop, laboratory or factory where temperatures from 300°F to 2250° F are required. They are used for heat treating metal, assaying and all types of testing.

Temperature controls: Auto tuning microprocessor-based controller.

Elements: High temperature iron-aluminum alloy wire elements are coiled and mounted on the side wall in porcelain plates.

The C133 Has a bottom element mounted in groves in floor and covered by refractory heart plate.

Model C136 assaying furnace has no bottom element and the side elements are raised 1.75" above the floor to prevent burnout due to spillage.

General construction: Case is constructed of heavy gauge sheet steel and finished in gray hammertone. The easily operated, counter-balanced door is always away from operator. All walls and door are constructed of the finest quality insulating fire brick backed by 1800° F block insulation. Comes complete with cord and plug.

Safety switch: These models come equipped with two door safety switches. When door is opened, elements are disconnected from power source. Solid state zero voltage switching of power to elements.

How To Select a Furnace

"Heat Treating Furnaces" also known as hardening furnaces
Heat treat (Hardening) furnaces have higher heat output power than draw furnaces due to the elevated temperatures at which they operate. Heat transfer to the tool steel is accomplished by a very efficient process called direct radiation. Temperature uniformity in these furnaces is best in the red heat range. Normal maximum temperature is 1232°C (2250°F). Optional 1316°C (2400°F.) maximum temperature versions are available.

Uses: These furnaces are designed for general use in the shop, laboratory or factory where temperatures from 300°F to 2250°F ±25 °F are required. They are used for heat treating metal, assaying and all types of testing. 2400° F maximum temperature option available at additional cost.

Temperature Controls: Auto tuning microprocessor-based controller.

Heating elements: Alloy wire elements are coiled and mounted on the side walls in easy to change porcelain plates.

General construction: The furnace case is constructed of heavy gauge sheet steel and finished in gray hammertone. The walls and door are constructed of the finest quality insulating fire brick backed up by 1800°F block insulation.

Safety switch: These models come equipped with dual door safety Switches. when the door is opened, power is disconnected from the heating Elements.

Door: The counter balanced easy to operate door, opens up and away from the furnace, keeping the hot side away from the operator.

A Kaowool® rope seal is installed on the door where it meets the Chamber.

How To Select a Furnace

"Draw Furnaces" also known as annealing, tempering or forced
Draw furnaces are used for tempering and other low temperature processes. They normally operate at temperatures below red heat range where heat transfer to the tool steel is accomplished by the process of convection heat transfer. To increase convection efficiency, these furnaces are equipped with a fan in the heating chamber to move air (Forced Convection). This delivers a temperature uniformity of ± 6°C (± 10°F) or better. Maximum temperature is 677°C (1250°F.). Optional 1093°C (2000°F.) maximum temperature versions are available

Draw Units: These models are equipped with a stainless steel fan and motor for forced convection temperature uniformity.

Uses: These furnaces are designed for general use in the shop, laboratory or factory where temperatures from 300-1250°F. ±10°F are required. They are used for such purposes as tempering, annealing and stress relieving. 2000°F maximum temperature option is available for all models at additional cost.

Temperature Controls: Auto tuning microprocessor-based controller and solid state relays for precise temperature control.

Heating Elements: Alloy wire elements are coiled and mounted on the side walls in easy to change porcelain plates.

General Construction: The furnace case is constructed of heavy gauge sheet steel and finished in gray hammertone. The walls and door are constructed of the finest quality insulating fire brick backed up by 1800° F block insulation. Comes complete with cord and plug.

Safety Switch: These models come equipped with dual safety switches. When the door is opened, power is disconnected from the heating elements and fan motor.

Door: The counter balanced easy to operate door, opens up and away from the furnace, keeping the hot side away from the operator.

A kaowool® Rope seal is installed on the door where it meets the chamber.

How To Select a Furnace

Uses: Designed for those who desire a hardening furnace, a quench tank plus a separate furnace for tempering or drawing all within a Minimum floor space. The two chambers allow for immediate tempering or drawing after quench without waiting for the hardening furnace to cool to the lower temperature required.

Controls: Both chambers are equipped with their own electronic control, thermocouples and solid state relays. Auto tuning microprocessor based controls are accurate to ± 1/4 of 1%. Each chamber is equipped with door safety switches that remove power from that chambers heating elements and fan blower.

Heating Elements: Alloy wire elements are coiled and mounted on the side walls in easy to change porcelain plates.

General Construction: Case is constructed of galvanized sheet metal and mounted in angle steel frame. Space is provided for air circulation between chambers, the quench tank is stored beneath the lower chamber and can be rolled out for use. The control panel face is attractive brushed stainless steel.

The upper chamber door rises vertically, the lower chamber door swings to the side. A heavy duty chrome plated latch is used to hold the lower door closed. The lower chamber is equipped with a stainless steel, centrifugal type fan to circulate the air and provide very close temperature gradients. The fan is operated by a 1/4 HP motor.

Easy access to controls and wiring is provided by removable side panel on control cabinet.

Welded steel plate quench tank on caster is standard on most dual units. Door seal is standard for inert protective atmosphere on 2250°F chambers.

How To Select a Furnace

Uses: These furnaces are designed for heavy duty, larger volume jobs requiring controlled temperatures up to 2100°F continuous or 2250°F intermittent.

Controls: These furnace come standard with a digital programmable main control and a digital high limit safety control. Solid state power switching to the heating elements, and dual door limit safety switches that interrupt power to the elements when the door is opened.

Elements: High temperature alloy wire elements are mounted in porcelain plates on the walls and floor and in grooves in the brick door, this provides all around heating and close gradients throughout the furnace chamber. A ceramic hearth plate covers the floor element.

General Construction: Case is finished in a pleasing gray hammertone. The counter-weighted vertical rising door keeps the hot face away from the operator, it opens easily, remains securely in both the open and close positions and includes a kaowool® rope seal. All walls and door are constructed of 4 1/2" of the finest quality insulating fire brick backed up by 2" of 1800°F block insulation. This combination of insulation and wall thickness helps to give fast heat up and excellent heat retention for economical operation.

How To Select a Furnace

Uses: Designed for those who desire a large hardening furnace plus a separate furnace for tempering or drawing, all within a Minimum floor space. The two chambers allow for immediate tempering or drawing after quench without waiting for the hardening furnace to cool to the lower temperature required.

Controls: These furnaces come standard with two sets of individual digital programmable control and a digital high limit safety control. Solid state power switching to the heating elements. Each chamber is equipped with dual door limit safety switches that interrupt power to the elements when the door is opened. Fan stops when lower door is opened. (Note: door blocks view of the lower set of controls)

Elements: High temperature alloy wire elements are mounted in porcelain plates on the walls and floor and in grooves in the brick door, this provides all around heating and close gradients throughout the furnace chamber. A ceramic hearth plate covers the floor element.

General Construction: Furnace frame is constructed of heavy steel angle with 18 gauge sheet steel metal panels to form exterior case. Door of upper unit rises vertically and the door of the lower unit swings to the side. A Kaowool® rope seal is installed on the upper and lower doors where it meets the chamber for an inert protective atmosphere. A chrome refrigerator latch is used to hold the lower door closed. Lower unit is equipped with an stainless steel, centrifugal type fan to circulate the air and provide very close temperature gradients. The fan is operated by a 1 HP motor.

How To Select a Furnace

Uses: This large capacity furnace can be used for various types of heat treatment processes which require temperatures up to 2100°F continuos temperature or 2250°F intermittent.

Controls: These furnaces come standard with a digital programmable main control and a digital high limit safety control. Solid state power switching to the heating elements, and dual door limit safety switches that interrupt power to the elements when the door is opened. All wiring is complete and ready to be connected to your power source. Input controls allow operator to adjust temperatures of various zones so that uniform temperatures can be had throughout the chamber.

Elements: High temperature alloy wire elements are mounted in grooves on the walls and door, this provides all around heating and close gradients throughout the furnace chamber.

General Construction: Furnace frame is constructed of 2 1/2" x 2 1/2" x 3/16" angle steel with 18 gauge sheet steel panels. The door is mounted on heavy hinges on the side and secured in the closed position with a heavy duty latch. A Kaowool® rope seal is installed on the door where it meets the chamber. The exterior is finished in a hammertone gray enamel. Walls are constructed of 4 1/2" of insulating brick backed up by 2" of 1800°F block insulation.

The 24" x 24" x 30" chamber in the C30FHWC gives you 10 cubic ft. of space, and the 24" x 24" x 36" chamber in the C36FH gives you 12 cubic ft. of space.
Standard 240 VAC, 3 Phase . 208 or 480 VAC optional. Also available with an optional vertical rising door.

How To Select a Furnace

Uses: This large capacity furnace can be used for various types of heat treatment processes which require temperatures from 200°F to 1950°F. The 6 bladed axial flow fan mounted in the roof circulates the air within the chamber resulting in close gradients throughout. OPTION: 2250 rating using a 4 zone control.

Controls: Furnace is equipped with Cress Electronic Control. The control, contactor and fan motor are all completely wired ready for simple connection to your power. A limit switch is mounted on the furnace body which automatically turns elements off when the door is opened. Programmable controls and recorder are also available as an extra. A back-up control, with a separate contactor and thermocouple, is standard.

Elements: Heavy chrome-nickel wire elements are coiled and mounted in grooves in walls and door to provide all around heating which also helps produce close gradients throughout the chamber. Solid state zero voltage switching of power to elements.

General Construction: Furnace frame is constructed of heavy steel angle with 18 gauge sheet metal panels to form exterior case. Case is finished in a pleasing gray hammertone. The vertical rising door is mounted on heavy levers and is opened by lifting up on a wide handle. The counterweight holds the door up in the raised position and the weight of the door gives a good brick to brick seal in the lowered position. A Kaowool® rope seal is installed on the door where it meets the chamber. This door protects the operator from burns because the hot surface always faces away from him. Door opens manually very smoothly and easily. All walls and door are constructed of 4 1/2” of the finest quality insulating brick backed up by 1 1/2" of block insulation. The roof is arched giving added strength and providing space for fan. This combination of insulation and wall thickness helps to give fast heat up and excellent retention for economical operation.

How To Select a Furnace

"Draw Furnaces" also known as annealing, tempering or forced
Draw furnaces are used for tempering and other low temperature processes. They normally operate at temperatures below red heat range where heat transfer to the tool steel is accomplished by the process of convection heat transfer. To increase convection efficiency, these furnaces are equipped with a fan in the heating chamber to move air (Forced Convection). This delivers a temperature uniformity of ± 6°C (± 10°F) or better. Maximum temperature is 677°C (1250°F.). Optional 1093°C (2000°F.) maximum temperature versions are available

Uses: These furnaces are designed primarily for annealing glass, and use as a bake out oven. However, it can be used for any purpose requiring controlled temperatures of up to 2250°F. When enquiring, please state temperature desired.

Controls: These furnaces come standard with a digital programmable main control and a digital high limit safety control. Solid state power switching to the heating elements, and dual door limit safety switches that interrupt power to the elements when the door is opened.

Elements: High temperature alloy wire elements are mounted in grooves in the brick walls. The design of the heating coils provides all around heating and close gradients throughout the furnace chamber.

General Construction: Heavy angle steel frame with 18 gauge sheet metal panels form the case. The walls are constructed of 4.5" of the finest quality insulated firebrick backed up by 1800°F block insulation. Counterweight lid opens easily. The lid is insulated with ceramic fiber. This combination of insulation and wall thickness helps to give fast heat up and excellent heat retention for economical operation.

How To Select a Furnace

Digital temperature controls fall into two basic types, process controllers and high limit controls (over temperature controls).
Process Controls handle the temperature and time requirements of the heat treat processes. These controls come in two types, non-programmable (single set point) and programmable.
Non-Programmable controls such as the model 935 are a single set point control, you simply input the desired temperature, along with a length of time to hold this temperature once achieved. The furnace heats to the desired temperature as fast as possible, holds for the amount of time, then ends the process. At the end of the process, the control can either hold the temperature or let the furnace cool down. The timer can be disabled. When disabled the control only requires a temperature setting input. The furnace will stay at the set temperature until changed or turned off. This is the least expensive standard control.
Programmable Controls such as the models SD4R and the F4H allow the heat up rate to be controlled, temperature can be ramped down as well as ramped up, multi-step heat treating can be input as a single process, and heat treat process programs can be stored in the controls memory for easy and accurate repeatability. In manual mode (non-program), the controls work the same as the model 935 with the timer disabled.
High Limit Controls such as the model LV help protect the furnace and load in the case of a failure in the primary (process) control or other related primary control loop components. The high limit control loop is completely independent of the primary control loop.
All control types are available with an optional audible alarm feature, which can signal a given process point or end of process.
The programmable process controls are available with an optional data communication package which allows full control interface with a computer.