SU1307451A1 - Method of automatic control of baking oven thermal conditions - Google Patents

Abstract

The invention relates to baking processes in the baking industry and can be used in other industries to control the heat regime of ovens with significant thermal inertia and. aims to save fuel and improve the quality of baked products. The method of automatic control of the thermal regime of a baking oven consists in regulating the supply of fuel to the gas burner 3 depending on the furnace load, determined depending on the total mass of dough pieces per unit of time using the mass sensor 7, with a time delay tj determined by the difference between time t | Proofings and the transition time tj of the oven, and with the correction for the oven temperature Measured by the temperature sensor 5 installed in the baking chamber (PC) of the oven 4. At this time, the change in time pa1 :: stroke is determined by. accounting data on the thermal inertia of the furnace 4, stored in the memory S ko fO Thebes.1.

Description

MHKponpv eccopa I (M), and the duration of proofing (controlled by sensor 8) so that, by the time the dough pieces are transplanted from conveyor 9 of proofing cabinet 6 to conveyor 10 of furnace 4, the amount of heat emitted by PC heating surfaces corresponds to the new value furnace load. Simultaneously1

The invention relates to baking processes of bakery products in the baking industry and can be used in other sectors of the industry to control the thermal regime of ovens with significant thermal inertia.

Purpose . invention - saving fuel and improving product quality.

. The method of automatic control of the thermal regime of a baking oven consists in regulating the fuel supply depending on the furnace load with a time delay and corrected by the oven temperature, the delay time being determined by the difference between the proofing time and the transient time of the oven, the furnace load is set to depending on the total mass of the test billets per unit of time entering the growth chamber.

FIG. shows the implementation of the proposed method of regulating the thermal mode of the furnace; on - timing charts showing the sequence of operations

The letter A denotes the input of the microprocessor, intended: to enter data on the type of product, quality test, etc.

In the initial stage of operation of the furnace, in the presence of conditions for safe gas combustion (gas pressure within the prescribed limits, presence of vacuum in the furnace), the microprocessor uses the program recorded in its memory block 2 to burn the gas burner 3 and output the furnace 4 to heat mode, while the temperature of the medium of the baking chamber is contour, with the dough billets being fed into the oven 4, the current temperatures of the medium PC are compared with the calculated value and, depending on the comparison result, are produced using M A section of mathematical dependencies recorded in the f block 2 of the memory, which is used to calculate the gas flow rate. 2 Il.

Rolled by means of a temperature sensor 5 installed in the baking chamber of the oven 4.

Using data on the dynamic parameters of the oven stored in memory block 2, the microprocessor 1 is predicted. The time when the temperature of the medium of the baking chamber reaches the specified value. The duration of the proofing is simultaneously calculated. When, until the end of the process of heating the furnace, there remains a period of time equal to the calculated duration of the proofing, the loading of proofing board 6 is started with dough pieces. In this case, the total mass of dough pieces arriving on the proofing unit of time (i.e. loading) is determined using the mass sensor 7. Data on the mass of dough pieces entered into the microprocessor 1 "

Using this data, the data about the test and the type of products are determined by the mathematical dependencies stored in memory block 2, the microprocessor calculates the amount of heat needed to bake the products, the mass of which is measured, and change the flow rate accordingly. gas supplied to the gas burner 3. The time at which the gas flow rate is changed is determined taking into account data on the thermal inertia of the furnace 4 stored in the memory of the microprocessor and the duration of the proofing controlled by the sensor 8, with this calculation to the time of transplantation of dough pieces from the conveyor 9 proofing cabinet 6 on the conveyor 10

Oven A (i.e., by the time the blanks were supplied to the oven), the amount of heat generated by the heating surfaces of the baking chamber corresponded to the new load value of the oven. Simultaneously with the feeding into the oven 4 dough pieces, the current value of the temperature of the medium of the baking chamber is compared with the calculated value. If this temperature does not match the specified value, a microprocessor 1 is used to make an appropriate correction of the mathematical dependencies recorded in memory block 2 for which the gas flow was calculated. The calculated temperature of the medium of the baking chamber is calculated using the microprocessor 1 according to the type of product, quality

test, the actual duration of proofing and the actual duration of baking using sensor 1 1. The task of the duration of baking calculated according to the form. product and quality of the test, and the task for the duration of proofing - according to the same data and taking into account the temperature value in the proofer 6, controlled by the sensor 12.

The following notation is used in the diagrams: t - time; N. - load

ka proofer (mass of dough pieces loaded into the cabinet per unit of time); P - gas consumption; Hp - kiln load Mass of dough pieces loaded into the kiln per unit of time); Q - the amount of heat entering the baking chamber. During the operation of the furnace, calculate the length of time

()

g

where tj is the time delay for changing the flow rate;

t. - duration (time) proofing;

t is the time interval from the moment the gas flow rate changes to the moment the furnace load changes, corresponding to 1 Sh.y this flow rate change (furnace transition time).

From the moment the load changes at the entrance to the proofer 6 (point 1), the microprocessor 1 starts counting the time delay and simultaneously calculates the value of this

holders by the formula (I). The tj value, calculated taking into account the thermal inertia of the furnace (taking into account the transport delay and constant furnace time), can be calculated once and periodically adjusted if necessary.

The value of t is calculated on the basis of current data on the type of product, quality of dough and temperature in the proofer. After the expiration of the time interval t (point 2) in accordance with the new load value (the value of Нр to the right of point 1), the gas flow is changed. After time t (point 3), the furnace load changes. At this point in time, the new value of the amount of heat entering the baking room is set.

camera 9

p, corresponding to the new value of the furnace load. If the actual temperature value at point 3 does not correspond to the calculated value, then the mathematical dependencies used to calculate the new value of the gas flow are corrected at the point corresponding to the new load of the proofer.

The application of the proposed method in the bakery industry to control the thermal regime of baking ovens saves fuel by reducing its consumption in advance while reducing the furnace load, especially when controlling the thermal regime of ovens with high thermal inertia.

In addition, more accurate maintenance of the temperature setpoint in the baking chamber allows higher quality products to flow.

Claims (1)

Invention Formula Automatic control method. nor the thermal regime of the baking oven, which provides for the regulation of the fuel supply depending on furnace load and furnace temperature measurement, characterized in that, in order to save fuel and improve product quality, the furnace load is predicted depending from the total mass of dough pieces per unit of time entering the proofer, and the regulation of the fuel supply is carried out with a time delay and with correction 51307451 the furnace temperature, the time between the proof time and the delay time being determined by the difference in the furnace transition process. .2