DE1067836B - Process for pressure control for ovens, especially for iron and steel processing, and arrangement for implementation - Google Patents

Description

GERMAN

In industrial furnaces, especially for iron and steel processing, preferably for annealing, is the pressure inside the furnace is kept constant by means of a regulator. In the course of the annealing process then the setpoint for the pressure regulator changed manually on a case-by-case basis.

The invention relates to a method which has an adjusting element for regulating the pressure for ovens, in particular for iron and steel processing, preferably annealing, which is a enables automatic regulation of the furnace pressure. According to the invention, the amount of energy supplied is measured, the furnace pressure measured and set to the maximum setpoint and the setting element for the furnace pressure in a preferably electrical follow-up control device with that supplied to the furnace Adjusted energy as a reference variable. In the case of gas or oil-fired stoves, the reference variable can be the Sequence control device be the fuel or air amount supplied to the combustion point or points, while In the case of electric ovens, the reference variable of the sequential control device is expediently the one fed to the oven electrical power is. In practical implementation, the arrangement is advantageously made in such a way that that a current corresponding to the energy supply to the furnace and a pressure difference of the furnace interior with respect to the external pressure is essentially proportional current of a comparing device are supplied, which acts on the one or more setting members for the furnace pressure.

The furnace pressure which is established in the process according to the invention is in accordance with technological requirements, e.g. when there is a large amount of heat supplied, as long as the goods heated in the furnace are not heated up the desired temperature is higher than the heat input that only reduces the furnace losses has to cover. In particular, when the item to be heated has reached the desired temperature, there is no There is more pressure difference between the inside and outside of the furnace.

It has already been proposed (British Patent 630,962), the in a gas-fired oven To regulate the furnace draft or the gas supply depending on the furnace temperature. But neither finds a measurement of the pressure prevailing in the furnace or a measurement of the amount of energy supplied instead of. Such a device is unable to give a clear picture of what is prevailing in the furnace To deliver pressure ratios, and the control of the energy supply or the furnace train as a function the temperature also has the disadvantage that external. Influences in the fuel and Air supply can significantly influence the furnace pressure and especially as long as the material to be inserted is in use

Pressure control method for ovens,
especially for iron and

Steel processing,
and arrangement for implementation

Applicant:

Siemens & Halske Gesellschaft mbH,
Vienna

Representative: Dipl.-Ing. C. Wallach, patent attorney,
Munich 2, Kaufingerstr. 8th

Claimed priority:
Austria from August 12, 1954

Paul Louis Wachendorfer, Genoa (Italy),

and Ing.Rudolf Bourek, Vienna,
have been named as inventors

Has not yet reached the target temperature, an uneconomical amount of energy is being supplied to the furnace.

An embodiment of the invention is shown in the drawing. This example relates on a gas-fired stove. In such ovens, as well as z. B. in the case of oil-fired stoves the or the amount of air supplied to the burners, depending on the calorific value of the fuel in a certain The relationship to the amount of fuel is a measure of the energy, in particular the supply of heat energy to the oven, serve.

In the figure of the drawing, 1 is an oven, e.g. B. for iron or steel annealing with the combustion point 2, the gas is supplied via the line 3 and air in the appropriate ratio via the line 4. In the exhaust duct 5 of the furnace, a flap 6 is provided which, for. B. can be opened more or less by the electric motor 7, which also changes the pressure inside the furnace.

A flow meter, preferably a ring balance 8 with electrical torque compensation, is connected to the air line 4, the output current I _{1 of} which is accordingly proportional or essentially proportional to the amount of air supplied to the furnace and thus also proportional to the thermal energy supplied to the furnace. The pressure inside the furnace

"....,. ... .., 909 640/292

The external pressure is measured by means of a pressure difference meter, preferably also with a ring balance 9 with electrical torque compensation, whereby the output current i _{2 of} this ring balance is proportional to this pressure difference. The currents I ₁ and i ₂ are fed to a comparison device, .Z.-B / the windings of a current comparison relay 10.

■ As long as the pressure in the furnace corresponds to the pressure assigned to the amount of heat or air supplied corresponds, the tongue 11 of the Stromyer balance relay 10 is in the zero position. If there is a deviation of the pressure of the value assigned to the inflowing air volume, the relay tongue strikes after the one or the other side and closes the '-.' circuit for the · motor 7, which is in. the one or other direction, begins to run and the flap 6 opens or closes until it is again in Furnace 1 has set the pressure that is assigned to the heat energy supplied in each case.

The dependence between the amount of air and the furnace pressure can be determined by the resistor 12 or by weight loading of the ring balance body can be set as desired and thus adapted to the requirements. In particular, this makes it possible for the pressure difference between the internal furnace pressure to disappear and external pressure at a certain value of the supplied amount of energy or air. reach.

In electric ovens, where the electrical power is used as the reference variable for the sequence control device, the electrical power can be converted into a proportional current by means of a transducer, which replaces the current i ± in the sequence control circuit according to the drawing. In the case of oil-fired stoves, the amount of oil can also be converted into a proportional electric current by means of an oil meter. Such an oil meter can, for. B. drive a tachometer dynamo, which converts the flow rate into a proportional voltage and thus into a proportional current.

Claims (5)

Claims 1. Process for pressure regulation for furnaces, especially for iron and steel processing, with an adjusting member for pressure regulation, characterized in that the amount of energy supplied measured, the furnace pressure measured and set to the maximum setpoint and that Setting element for the furnace pressure in a preferably electrical slave control device groove the energy supplied to the furnace is adjusted as a reference variable. 2. The method according to claim 1, characterized in that with gas or oil-fired Furnaces as the reference variable of the sequential control device supplied to the burning point (s) (2) Amount of fuel or air is used. 3. The method according to claim 1, characterized in that that in electric ovens as a reference variable of the follow-up device the dem Furnace supplied electrical power is used. 4. Arrangement for a method according to one of the preceding claims, characterized in that that a current corresponding to the energy supply to the furnace and a pressure difference of the furnace interior with respect to the external pressure is essentially proportional to a current Comparison device (IQ) are fed to the one or more setting members (6, 7) for the Furnace pressure acts. 5. Arrangement according to claim 4, characterized in that in gas or oil firing a ring balance (8) with electrical torque compensation that measures the amount of air supplied and a further ring balance (9) with electrical torque compensation is provided are, whose output currents are a current comparison relay that controls the setting element for the furnace pressure (10) are supplied. Considered publications:
British Patent No. 630 962. 1 sheet of drawings ® 909 640/292 10.