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The multiconveyor convection oven comprises a baking chamber, at least two spaced-apart conveyors mounted transversally one over the other in the baking chamber, a heating chamber behind the baking chamber. A convection system is provided for allowing a circulation of the air from the baking chamber

The multiconveyor convection oven comprises a baking chamber, at least two spaced-apart conveyors mounted transversally one over the other in the baking chamber, a heating chamber behind the baking chamber. A convection system is provided for allowing a circulation of the air from the baking chamber to the heating chamber and back to the baking chamber to cook the food. The convection system comprises air return passages providing a fluid communication between the baking chamber and the heating chamber, a blower housing extending vertically outside the heating chamber on a side thereof, at least two centrifugal blower chambers, one for each conveyor, mounted one over the other within the blower housing. Each centrifugal blower chamber has an air inlet in fluid communication with the heating chamber for drawing air from the baking chamber and an air outlet for throwing back heated air at high pressure. The convection system also includes plenum chambers and ducting means disposed within the baking chamber for conveying the heated air at high pressure exiting from the plenum and dispensing the same in the baking chamber to cook food.

대표청구항 ▼

The multiconveyor convection oven comprises a baking chamber, at least two spaced-apart conveyors mounted transversally one over the other in the baking chamber, a heating chamber behind the baking chamber. A convection system is provided for allowing a circulation of the air from the baking chamber

The multiconveyor convection oven comprises a baking chamber, at least two spaced-apart conveyors mounted transversally one over the other in the baking chamber, a heating chamber behind the baking chamber. A convection system is provided for allowing a circulation of the air from the baking chamber to the heating chamber and back to the baking chamber to cook the food. The convection system comprises air return passages providing a fluid communication between the baking chamber and the heating chamber, a blower housing extending vertically outside the heating chamber on a side thereof, at least two centrifugal blower chambers, one for each conveyor, mounted one over the other within the blower housing. Each centrifugal blower chamber has an air inlet in fluid communication with the heating chamber for drawing air from the baking chamber and an air outlet for throwing back heated air at high pressure. The convection system also includes plenum chambers and ducting means disposed within the baking chamber for conveying the heated air at high pressure exiting from the plenum and dispensing the same in the baking chamber to cook food. 1. An ignition device for an internal combustion engine comprising: a power transistor for controlling a primary current flowing through an ignition coil by its flowing and blocking operation in response to an ignition control signal inputted externally; and an abnormal current flowing prevention circuit for forcing said primary current to be cut off in case where said control signal was inputted representative of current flowing lasting over a predetermined period of time, said abnormal current flowing prevention circuit being integrated on a silicon substrate together with said power transistor, wherein said power transistor is an insulated gate type bipolar transistor, and said circuit is made up by a self-separation type NMOS transistor isolated by a p-well layer within said silicon substrate. 2. An ignition device for an internal combustion engine comprising: a power transistor for controlling a primary current flowing through an ignition coil by its flowing and blocking operation in response to an ignition control signal inputted externally; and an abnormal current flowing prevention circuit for forcing said primary current to be cut off in case where said control signal was inputted representative of current flowing lasting over a predetermined period of time, said abnormal current flowing prevention circuit being integrated on a silicon substrate together with said power transistor, wherein a Zener diode and a resistor connected in parallel with said Zener diode are included in said ignition control signal input stage, and wherein the Zener voltage of said Zener diode is made over a maximum voltage of said ignition control signal, its direction is such that clumping occurs with a voltage drop corresponding to Vf of the diode. 3. An ignition device for an internal combustion engine comprising: a power transistor for controlling a primary current flowing through an ignition coil by its flowing and blocking operation in response to an ignition control signal inputted externally; and an abnormal current flowing prevention circuit for forcing said primary current to be cut off in case where said control signal was inputted representative of current flowing lasting over a predetermined period of time, said abnormal current flowing prevention circuit being integrated on a silicon substrate together with said power transistor, wherein said abnormal current flowing prevention circuit comprises a reference pulse generating circuit for detecting that the ignition control signal is inputted over the predetermined period of time, a digital timer made up by a digital counter, and a latch circuit for carrying out latching with the digital timer output signal and dropping a gate voltage of an IGBT to carry out resetting when the ignition control signal is off. 4. An ignition device for an internal combustion engine comprising: a power transistor for controlling a primary current flowing through an ignition coil by its flowing and blocking operation in response to an ignition control signal inputted externally; and an abnormal current flowing prevention circuit for forcing said primary current to be cut off in case where said control signal was inputted representative of current flowing lasting over a predetermined period of time, said abnormal current flowing prevention circuit being integrated on a silicon substrate together with said power transistor, a current limiting circuit for preventing over-current of said primary current, said current limiting circuit being integrated on said silicon substrate, an input control for controlling said power transistor in response to said ignition control signal inputted, said input control circuit being integrated on said silicon substrate, of which control system supplies said ignition control signal of which voltage is over 3 V with respect to ground, wherein the power supply is supplied from said ignition control signal, and the current flowing threshold value for said ignition control signal is less than 3 V. 5. A one-chip type ignition device for an internal combustion engine comprising: an insulated gate type bipolar power transistor by which a high voltage is generated at a secondary side of an ignition coil by a flowing and blocking control of primary current through the ignition coil in response to a control signal outputted from an internal combustion engine electronic control apparatus; an input control circuit having a threshold value and a hysterisis, for controlling a gate voltage of said insulated gate type bipolar power transistor in response to said control signal inputted; a current limiting circuit for preventing the over-current of said primary current; and an abnormal current flowing prevention circuit for forcing the primary current to be blocked in case where said control signal was inputted representative of the current flowing over a predetermined period of time; and wherein said insulated gate type bipolar power transistor, said input control circuit, said current limiting circuit, and said abnormal current flowing protection circuit are integrated on a silicon substrate, said control circuit is made up by a self-separation type NiVIOS transistor isolated by a p-well layer within said silicon substrate. 6. A one-chip type ignition device for an internal combustion engine comprising: an insulated gate type bipolar power transistor by which a high voltage is generated at a secondary side of an ignition coil by a flowing and blocking control of primary current through the ignition coil in response to a control signal outputted from an internal combustion engine electronic control apparatus; an input control circuit having a threshold value and a hysterisis, for controlling a gate voltage of said insulated gate type bipolar power transistor in response to said control signal inputted; a current limiting circuit for preventing the over-current of said primary current; and an abnormal current flowing prevention circuit for forcing the primary current to be blocked in case where said control signal was inputted representative of the current flowing over a predetermined period of time; and wherein said insulated gate type bipolar power transistor, said input control circuit, said current limiting circuit, and said abnormal current flowing protection circuit are integrated on a silicon substrate, wherein a Zener diode and a resistor connected in parallel with said Zener diode are included in said ignition control signal input stage, and wherein a Zener voltage of said Zener diode is made over a maximum voltage of said ignition control signal, its direction is such that clumping occurs with a voltage drop corresponding to Vf of the diode. 7. A one-chip type ignition device for an internal combustion engine comprising: an insulated gate type bipolar power transistor by which a high voltage is generated at a secondary side of an ignition coil by a flowing and blocking control of primary current through the ignition coil in response to a control signal outputted from an internal combustion engine electronic control apparatus; an input control circuit having a threshold value and a hysterisis, for controlling a gate voltage of said insulated gate type bipolar power transistor in response to said control signal inputted; a current limiting circuit for preventing the over-current of said primary current; and an abnormal current flowing prevention circuit for forcing the primary current to be blocked in case where said control signal was inputted representative of the current flowing over a predetermined period of time; and wherein said insulated gate type bipolar power transistor, said input control circuit, said current limiting circuit, and said abnormal current flowing protection circuit are integrated on a silicon substrate, wherein said abnormal current flowing prevention circuit comprises a reference pulse generating circuit for detecting