US 5,197,375 A · Conveyor oven control

Abstract

A control device for a multi-zone conveyor oven constructed according to the present invention comprises a microprocessor-based controller, appropriate control software, a keyboard and display for interaction with a user, means for sensing the conveyor speed and the heating chamber temperature, and means for controlling the power supplied to the conveyor motor and the heating elements. The controller provides facilities for user programming of sets of oven parameters, each set corresponding to a particular food product to be cooked in the oven. Each set of parameters includes the total cook time for the product and a desired temperature which is independently selectable for each heating zone. Once a set of parameters has been programmed, it is assigned to a particular key on the keyboard, and the user may select that entire set of parameters by simply pushing the assigned key. The parameters are stored in the EEPROM to prevent their loss during electrical power inteerruptions. High-accuracy, low hysteresis temperature control of the oven is provided by pulse-width-modulating the power supplied to the heating elements. Accurate and repeatable control of cooking time is provided by controlling the speed of the motor driving the product transport conveyor. Such control is provided by pulse-width-modulating the powere supplied to the motor according to motor speed information derived by sensing the motor shaft position. The controller also provides extensive fault detection, and degrades oven preformance as gracefully as possible.

Claims27

Dependent claims

A hysteresis-less control device for an oven having at least one cooking region and at least one means for heating said region;

said control device comprising:
means for receiving from a user a desired temperature selection to be produced by said heating means in said cooking region;
means for measuring a temperature in said cooking region;
means for supplying heating energy to said heating means;
and means operating over a continuous range of cooking region temperatures extending from above to below said desired temperature selection, in response to said temperature measurement means and to said temperature selection means, to adjust the average amount of heating energy supplied to said heating means so as to produce a temperature closely approximating said desired temperature selection.

2 more elements

A control device for an oven having a cooking region and means for transporting a product through said cooking region, said control device comprising:

means for receiving from a user a desired cooking time selection;
means responsive said desired cooking time selection for controlling the operating speed of said product transport means to maintain the product within said cooking region for a time equal to said cooking time selection;
said operating speed controlling means having:
means for measuring the operating speed of said product transport means;
means for supplying motive energy to said product transport means;
and
means responsive to said operating speed measurement means and said desired cooking time selection for adjusting the amount of said motive energy supplied to said product transport means to produce a cooking time closely approximating said desired cooking time selection.

4 more elements

Dependencies are inferred from the claim text.

Conveyor oven control

Life of this patent

Conveyor oven control

Life of this patent

Abstract

Claims27