SU780079A1 - Method of regulating temperature in cathode-ray equipment - Google Patents

Description

(54) METHOD FOR REGULATING TEMPERATURE IN ELECTRON-BEAM INSTALLATION

I

The invention relates to electrical engineering and can be applied to heat objects in an electron beam installation.

The known method of heating objects in electron-beam installations using the redistribution of electron beam energy over the object's surface, is implemented in device 1. According to this method, according to a given program, the maximum heat input density in places of intense heat sink and energy shadow is achieved by reducing the speed of movement of the electron beam surface. This method, however, does not allow sufficiently accurate maintenance of the temperature on the object's surface, since random perturbations in the heating process distort the specified temperature distribution.

The closest technical solution to the present invention is a method of temperature control during electron beam heating, implemented in a known device, according to which a heated electron beam is applied to the surface of the heating object, which sets the beam power signals, the speed of its movement and focusing, measures the temperature distribution at object surface, compare the measured temperature with a given field of temperatures, on the result. The tattoos form a mismatch signal at any point on the surface, and the power and speed of movement of the beam p vary over it.

However, when regulating the temperature with this method, local overheating occurs under the electron beam.

J5 beam focused on the surface of the object in a small spot of constant size, and, consequently, accelerated evaporation and deterioration of the structure of the matter. Besides

 The energy loss of the electron beam to evaporation and radiation increases. The aim of the invention is to improve the quality of the heating object by reducing local overheating and

25 metal evaporation losses.

The goal, achieved by the fact that they form an additional mismatch signal averaged over the entire surface, compares it

30 P indicated by the signal of dissipation.

form a difference signal, algebraically add it to a given focusing signal — and control the electron beam focusing by the sum signal.

On tHr.l (a, b, p, d, e, f, g) the graphs of the formation of the focusing control signal of the electron beam are shown in FIG. 1 (3) - the graphs of the distribution of the intensity of heat input in the spot of the energy effect depending on the current center coordinate of this spot, (at normal electron beam power); on fit. 2 - an example of a device that implements the proposed method. In Fig. 1, the following notation is accepted: X is the spatial coordinate, Y is the size of the object heated by the vertigo, T is the temperature, T is the set temperature, TC is the measured temperature, ir is the error signal, lGy is the additional antenna. mismatch signal, A-Up - differential signal, F y; - Focus correction signal of the electron beam, a given signal. electron beam focusing, F is the total signal of the earth focus of the beam 1 6 beam, q the heat input power density, dYI diameter of the energy source, the current coordinate of the center of the energy spot (XQ Xd (1). The definitions used in FIG. 2 .; 1 — electron gun, 2 — electron beam, 3 heating object, 4 — scanning pyrometer, 5 — comparing device, 6 — driver unit, 7 — electron beam power control signal forming unit, 8, speed control signal generating unitelectron beam motion, 9 - correction signal formation unit for locating the electron beam, 10 - program block, 11 - deflecting system, 12 - suimmator, 13 focusing system, 14 - energy spot, 15 crystallizer;; -v --.- - .. v., ™.,., i., ..., ...

The essence of the proposed method is as follows (see AIG,). The specified temperature distribution T (jp) (fig. La) on the object's surface during its heating in an electron-laser unit is constantly distorted due to various disturbing factors (gas emissions from the surface of the melt, changes in heat exchange conditions with the environment, changes in the heat constant material and others). Therefore, to stabilize the temperature at a given level, the actual temperature distribution T, (x) (fig.1a) on the surface of the object is measured, the set temperature is compared with the measured temperature, and

Up (x) signal (Fig. 16) mismatch.

Signal disagreement: more

 one

averaged (Up J J Up (x) d), additionally averaged signal U i

(Fig. IB) the mismatch is compared With the error signal and a difference signal u.Up (x) is obtained (Fig. 1d) g in proportion to which the signal F is generated, | (x) (Fig. 1e) of the electron beam focus correction. Received focus correction signal. they are folded algebraically with a given signal 1 (x) (Fig. 1e) for focusing the electron beam and for the resulting total signal F2 (x)

(Fig. 1g) control the focusing of the electron beam.

The algorithm for changing the parameters of a given focusing signal of an electron beam is preliminarily calculated on a computer. The basic, initial, prerequisite for the calculation is. minimization (with unchanged electron beam power).

power of heat input in the energy impact (to reduce local overheating and carbon loss of the material) taking into account specific heating conditions - a given temperature distribution, heat exchange conditions of an object with the environment, a given law of electron beam motion, etc. According to THIS, the electron beam moving over the surface of the object, more distributed (within the surface) in areas with lower heat transfer, for example, in the center of the object. Conversely, the dispersed electron beam is reduced in the areas of more intensive cooling, for example, at the edges of the object (see Fig. 1h).

As shown graphically on d) i.1c5, the power density distribution q of heat deposits inside the energy impact spot follows the HopWartbHoro Gaussian distribution q (x) Part. „, X × P (), l where qq (x is current value

  the maximum density of heat input in the spot of the energy impact,

k k (X (, - current value

electron beam concentration ratio ..

Q The concentration coefficient is associated with the electron beam focus control signal proportional to k (xd)), where Y is the proportionality coefficient.

The diameter d spot of the energy impact is conventionally determined at the level of 5% of the maximum value.

The preceding method can be implemented in the device shown in FIG. 2, as follows. Using an electron gun 1, an electron beam 2 is injected onto the surface of the heating object 3. The temperature distribution on the object's surface is measured by scanning with a pyrometer 4, and the signals corresponding to this temperature are fed to the comparative device 5. At the same time, signals corresponding to the specified temperature arrive , from the driver unit 6, in the comparison device, the error signals are generated, which are then fed to the unit. / (Normalization of the electron beam power control signal, block of formation of the electron beam speed control signal and block 9 of forming the electron beam focus correction signal. Blocks 7 and 8, in addition to the error signals, also receive the specified signals from the program block 1, control signals modularity, formed in block 7, is fed to the electron gun - for controlling the power of the electron beam, and the control signals, nor the speed, formed in block 8, are fed to the deflection system 11-d In order to control the speed of the electron beam, in block 9. The error signals are averaged, the averaged values are compared with the error signal and the difference signals are selected, in proportion to which the electron beam focus correction signals are generated. The correction signals as well as the specified focus signals from program block 10 , are algebraically folded in the adder 12. The resulting cy 1 m signals are fed to the focusing system 13 to control the focusing of the electron beam.

When using an electron beam nibble as a controlling influence in the process of temperature control in electron beam installations, the law of motion

The electron beam can be quite simple, easily implemented by instrumentation, for example, sinus, circular, spiral laws. The law of progressive scan and others.

The application of the proposed method in the processes of smelting metal in the molds will allow to obtain higher quality metal by reducing local overheating and carbon loss of the metal (or alloy components),

and reduce the loss of energy and metal to evaporate.

Claims (2)

1. Rogachev L.V. et al. The control device of the electron beam energy distribution over the target. Materials of the Scientific and Technical Conference of the SKGMI, Ordzhonikidze, 1972, pp. 273-275. 2. USSR author's certificate number 418836, cl. G 05 D 25/02, 1972. but I f TO x / V fui: 2