Cata-Dyne™ Infrared Oven

Operation and Instructional Manual - Definitions

Batch Timer

The batch timer is typically used in paint booth applications where a pre-set amount of heat is required. The oven runs in standby mode until the timer is started. The oven then runs at full heat mode until the timer period is completed. The oven then returns to standby mode. The operator starts the full heat cycle by momentarily pressing the Start Timer switch. The time is set with the Timer Up and Timer Down switch.

Cata-Dyne™ catalytic heaters do not burn fuel with an open flame but instead use a compound called a catalyst to combine the incoming fuel gas with oxygen to produce infrared energy.  A catalyst is a compound that accelerates the rate of a chemical reaction without being consumed by the reaction itself.  In Cata-Dyne™ heaters, electric elements must heat the catalyst to above the critical temperature before fuel gas is released to the heaters.

The control panel is a self-contained control system which controls the valves and contactors in an oven system. It can control up to 56 heaters in one to eight zones.  It contains a combination of oven control boards, displays, switches, fuses, relays, contactors, temperature controllers, modulating valve controllers, and timers. There are two sizes of control panel the smaller one is  32" H x 20" W x 8" D and the larger is 38" H x 26" W x 10" D.

The minimum temperature required for the catalyst to chemically combine fuel and oxygen is the critical temperature.  Below the critical temperature, there is no heat producing reaction.  The control system must not permit gas to flow to the heaters if the catalyst is below the critical temperature or the potentially explosive fuel gas will escape into the atmosphere.

Full Heat is the mode of operation where the oven runs at its fully rated temperature.  The maximum heat output may be controlled by flow regulators or by using a Temperature Controller and a modulating gas valve.

A modulating valve is an electrically operated valve that uses a signal (typically 0-20V DC) to control the amount of gas flowing through the valve.  A temperature controller is used to provide a signal to a Modulating Valve Controller, which controls the flow of gas and thereby the temperature of the oven system.  The modulating valves used by CCI Thermal have a low flow or standby output but have no off position.  Therefore each modulating valve must be used in conjunction with a solenoid valve for full on-off control.

The Modulating Valve Controller or Signal Conditioner is a device which takes either a 4-20 milliamp signal or a voltage derived from a potentiometer and translates it into a pulse of varying width to control a modulating gas valve.  A quad Modulating Valve Controller can drive up to four modulating gas valves from one to four temperature controllers.

A motorized valve is an electrically operated valve used as a main gas valve in Cata-Dyne™ oven system.  The valve will open when voltage is applied to the motor (typically 120 VAC).  The valve is either off or full on - there is no pressure or flow control.

A solenoid valve is an electrically operated valve.  The valve will open when voltage is applied to the coil (typically 24 VAC or 120 VAC).  The valve is either off or full on - there is no pressure or flow control.  Combinations of these valves allow for control of single or multiple zones.

Standby is the state in which the heater is burning the minimum amount of fuel required to keep the catalyst pad above the critical temperature.  Therefore its heat output is much lower than the normal operating state.  Standby is used to reduce fuel consumption when a full shutdown and the subsequent pre-heat cycle is not required or desired.

The timer will allow unattended startup and shutdown of the oven system. It can be programmed to start the oven at a different time each day of the week.

The Temperature Controller is a device which controls the temperature of the oven system.  There are currently two types of temperature control systems used; open and closed loop controllers. The closed loop temperature controller is a digital device which can be programmed for a wide range of temperatures.  A temperature sensor, typically a thermocouple, provides feedback so that the controller can hold the oven at a relatively constant temperature. The temperature controllers used can be programmed to receive a wide range of sensors but K type thermocouples are most commonly used.  The output signal is the industry standard 4-20 milliamp output.  This output is fed to an amplifier called a Modulating Valve Controller which provides the drive for a modulating valve which will in turn modulate the gas flow in proportion to the control input.

The Percentage Temperature Controller is an open loop temperature controller that uses a rotary control or potentiometer with markings that range from about 30% to 100%.  The operator can select a setting anywhere within that range. This output from the control is again fed to modulating valve controller which will provide the drive for a modulating valve which will in turn modulate the gas flow.  Because there is no feedback from a temperature sensor to compensate for changes to the oven, this is called open loop control.  This type of control is less expensive than a full digital controller and is used where there is little change to the oven conditions and temperature control is less critical.

A Variable Frequency Drive (VFD) is used in conjunction with a blower motor to provide variable air flow.  It is inserted into the circuit between the fuses for the motor and the motor itself.  A VFD will often appear with recirculation blowers in cure ovens, but could be used anywhere a blower motor is required.  Control of airflow is usually accomplished with a keypad interface or up/down buttons. 

Note: output wiring from the VFD to any motor it controls must be contained in a dedicated conduit to ensure electromagnetic isolation.

An oven zone is a group of heaters which act together.  They receive gas from a common valve and have electric preheat elements that are switched on at the same time.  Zones allow various portions of an oven to generate more or less heat than others.  This accommodates different heat requirements of the various sizes and materials of the objects which are cured or heated in an oven.  Zones may also be used to heat objects in stages to reduce thermal shock.  Zones can be either true zones with full control or thermal zones which share common electric control but have separate temperature controllers and modulating valves.  Thermal zones are less expensive to implement than true zones.

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