DE2418067A1 - Multideck baking oven control - boosts heat input for heating up period and reduces input before reaching working temp - Google Patents

Abstract

A multi-deck baking oven, fitted with a two-stage gas-or oil-fired burner and a flue gas circulation system is so controlled that the high heating input is applied during warming-up period. Just before the working temp. is reached, the input is reduced, manually or automatically, to the normal level. This ensures a speeded-up starting period but prevents burning the pastry by excessive heat, even when there is a frequent change in the baking periods. A simple time programmer cuts out the human element.

Description

Method and device for heating a deck oven Die The invention relates to a method and a device for heating a deck oven with one or more heating units, for example burners.

Deck ovens with single-stage burners are known in the art equipped, which are operated, for example, with oil or gas.

The temperature control in the individual baking rooms takes place via a Flue gas circulation via appropriate flue gas ducts and radiators on the upper and undersides of the individual baking rooms. When designing the burner output must In general, a compromise can be made that leads to an unfavorable baking behavior leads.

On the one hand, the burner should perform in terms of fast Heating up or heating up the oven should be as large as possible, while on the other hand smaller in terms of uniform burner operation when the oven is heated up have to be. Although in the latter case a relatively low output of the burner is sufficient, much larger burner capacities must be used for practical reasons in order to ensure acceptable heating times for the oven in the morning as well as during Change the baking program. This results in the main disadvantage that when heating up between two baking periods easily overheating occurs later affect the baked goods as so-called flames.

Furthermore, deck ovens have already been proposed that depend on on the baking volume, i.e. on the size and number of the in the flue gas circuit switched-on baking rooms have different burner outputs. For example a two-stage burner was proposed in this context, which is dependent on is switched from the baking volume. Such a measure is suitable for the intended purpose of a seasonal operation with constantly changing Requires baking space, but this does not avoid the disadvantages mentioned above, because, for example, for heating such a deck oven in turn the same compromise difficulties exist.

The present invention is therefore based on the object of an improved Method and a corresponding device for heating a deck oven to create with a burner and a flue gas circulation, always an optimal one Operating behavior with short heating times is guaranteed without the so-called Flaming phenomena occur on the baked goods.

The solution to the problem is given in a method of the above Kind achieved in that the control of the operating temperature when heating with increased heating output and after heating up with normal cooling output will. This eliminates all of the aforementioned compromise-related difficulties, because the large heating power required for a short heating-up time is sufficient Heating is reduced. The normal heating output that then sets in is that Adjusted the heat output requirement of the deck oven in operation and much smaller, so that, for example, a burner evenly in normal operation can go through. This results in a lower switching frequency as well less control processes required.

There is also no overheating of the heat exchangers between two baking periods Radiant surfaces on, so that the next baking period can be initiated safely can.

The heating power is expediently reduced before the operating temperature is reached switched back. This can, for example, be around 20-50 ° C below the operating temperature take place. The oven temperature increases very quickly to one when it is heated up certain temperature range below the operating temperature, after which a further slow activation to the operating temperature takes place. This will also avoids short-term overheating of the radiant surfaces, which then occurs would if the increased 'heating power only when the operating temperature is reached would be switched off.

In a very simple embodiment, the downshift the heating power is done by hand. For this purpose, for example, only one The performance of a changeable burner or at least one two-stage burner is required, which is changed by an operator after sufficient heating. In this case, there are no further control-related aspects to carry out the method Measures required.

However, it is much cheaper if the downshift is automatic is made. This can be time-dependent or dependent on, for example the difference between the operating temperature and the current temperature take place. The automatic switch back has the advantage that a monitoring can be omitted during heating and that the power reduction in any case is made safely. Because the increased heat output especially when very short Heating-up times are desirable, a considerable risk for the baked goods in continuous operation and also represents for the deck oven, the less reliable manual operation should reserved only in exceptional cases. With regard to the dependency of the power downshift the time control is particularly simple, since only a time recording from switching on until it is necessary to switch back.

The temperature-dependent downshift is even safer because it is always the influencing variables, the oven temperature or the flue gas temperature directly must be taken into account.

Furthermore, the control of the operating temperature can also be more can be made as two heating or burner output levels.

For example, it is possible to have a large one at the beginning of the heating process Provide power level, with ever decreasing power levels in time switched off one after the other. However, such a procedure is relatively complex and should only be reserved for special applications where it is not only on a quick overall heating, but also on a quick achievement the exact operating temperature.

A device is used to carry out the method according to the invention proposed, which is characterized by a direct to a full load line 28 a two-stage heating unit 16 or a selector switch that can be switched over to two parallel branches 26 and through one of the parallel branches optionally with a full load line 28 of the Heating unit 16 or to the selector switch 26 connecting switch 34, wherein in the parallel branches on the one hand a time relay 36 and on the other hand a temperature differential element 38 lying.

The selector switch enables direct control of the full load line For example, a two-stage bl or gas burner by hand or a switchover to an automatic mode, with the two parallel branches via the switch can optionally be switched off and a time- or temperature-dependent switch-off With such a device, all process steps can be carried out perform optionally so that only a single assembly is required. By the use of a selector switch can advantageously be used at any time in the automatic Operational sequence can be intervened manually if there is a fault on the timing relay or is present on the temperature differential element.

Another embodiment is that the two-stage heating unit as a two-stage heating unit or as a two-stage burner or as two separate single-stage heating units or burners is formed.

This results in a particular versatility of the invention Contraption. The same applies if a with oil and / or gas and / or Electricity-powered two-stage heating unit is used. In one and Different energy sources can be used at the same time for the same furnace to cover different power requirements when heating up also when baking.

The invention is illustrated below using a drawing Embodiment explained in more detail.

A deck oven lo has a baking chamber group 12.

All baking rooms are powered by a single burner via a circulation system 16 heated, and the - smoke or heating gases reach a common gas supply 18 in unspecified radiators above and below the baking rooms 12, are arranged. After flowing through the radiators, the heating gas is via a Gas recirculation 20 returned to the burner 16 to return to the after heating Radiators to arrive.

To achieve gas circulation and more even heating fans or the like, not shown, can of course be present be. -.

The individual baking chambers are over at the front-through flaps covered shooting openings accessible.

The temperature T in the individual baking chambers 12 is a Thermocouple 22 detected.

A selector switch 26 is on the one hand to control the oven heating directly to a full load line 28 of the burner 16 and on the other hand via a Changeover switch 34 connected to two parallel branches in which, on the one hand, a timing relay 36 and on the other hand a temperature differential element 38 are located. The parallel branches can with the changeover switch 34 optionally connected to the full load line 28 of the burner 16 will. The partial load line 30 is controlled directly by the thermal sensor 22.

When the switch 26 is turned on, the burner 16 is used for the purpose of Heating the deck oven 1o operated with an increased burner output, what for example by appropriate control of gas or oil valves or of Current regulators can be achieved.

Depending on the position of the switch 34, the switch-on signal of the Selector switch 26 either with a time dependency a t or as a function passed on from a temperature difference aT to the full load line 28 of the burner 16. When the changeover switch 34 is in the position shown in the drawing, when the selector switch 26 is switched on, the parallel branches start up of the timing relay 36, which after the time At to influence the full load line 28 and thus to a switch back of the increased burner output to the normal one Burner output leads.

When the changeover switch 34 is thrown, a corresponding downshift takes place only when the temperature difference element 38 has a certain temperature difference aT between the actual temperature and the target temperature. The target temperature is then controlled with reduced power.

Instead of the time- or temperature-dependent switch-back, a manual switch back can be made using the selector switch 26, however, an automatic switch back via one of the parallel branches is preferred will. For this reason, manual operation should be reserved for exceptional cases and can be used, for example, if the automatic links are defective, be waited or would have to be switched over for an exceptional operation. Although in principle no operator is required, it is for safety reasons constant manual intervention in the otherwise automatic process is possible.

The device is also very suitable for a subsequent Attachment to already existing deck ovens, as the burner control can also be used without changes initiated immediately by hand or automatically depending on the time on the deck oven can be. Any thermal sensors may not be used until later and wired, with a transition from time dependency to at any time Temperature dependence and vice versa is possible.

The device described thus enables in a simple manner Realization of all process steps according to the present invention. she is comparatively simple and inexpensive with the greatest possible versatility.

- patent claims -

Claims (9)

Claims method for heating a deck oven with one or more heating units, for example burners, characterized in that that the control of the operating temperature when heating with increased heating power and is carried out after heating up with normal heating power. 2) Method according to claim 1, characterized in that the heating power is switched back before the operating temperature is reached. 3) Method according to one or more of the preceding claims, characterized in that the downshift is carried out manually. 4) Method according to one or more of the preceding claims, characterized in that the downshift is carried out automatically. 5) Method according to claim 4, characterized in that the downshift takes place time-dependent. 6) Method according to claim 5, characterized in that the downshift depending on the difference between the operating temperature and the current one Temperature takes place. 7) Method according to one or more of the preceding claims, characterized in that the control of the operating temperature with more than two heating or burner output levels are carried out. 8) Device for performing the method according to one or more of the preceding claims, characterized by a direct to a full load line (28) of a two-stage heating unit (16) or switchable to two parallel branches Selector switch (26) and through one of the parallel branches, optionally with a full load line 28 of the heating unit (16) or the selector switch (26) connecting the switch (34), on the one hand a timing relay (36) and on the other hand in the parallel branches a temperature differential element (38) lie. 9) Apparatus according to claim 8, characterized) that that the Two-stage heating unit as a two-stage heating unit or as a two-stage burner or as two separate single-stage ones Heating units or burners are designed. 1o) Device according to claim 9, characterized by a with oil and / or gas and / or electricity powered two-stage heating unit. Blank page