USSR REVIEW OF BOOK ON HIGH-FREQUENCY HEATING OF ELECTRICS AND SEMICONDUCTORS

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00809A000700150374-9
• Release Decision: RIPPUB
• Original Classification: R
• Document Page Count: 5
• Document Creation Date: December 22, 2016
• Document Release Date: September 13, 2011
• Sequence Number: 374
• Publication Date: December 14, 1953
• Content Type: REPORT

Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9
COUNTRY USSR
PUBLISHED Monthly Periodical
WHERE
PUBLISHED Moscow
DATE
PUBLISHED Feb 1951
LANGUAGE Russian
CENTRAL uv T?C, Hsu
FOREIGN DOCUMENTS OR RADIO BROADCASTS CD N
SUBJECT DATE OF
Scientific - Electronics, high-frequency hrnti- INFORMATION 1950
Elektr- stvo, No 2, 1951, pp 92-94
NO. OF PAGES 5
THIS IS UNEVALUATED INFORMATION
HIGH_ FREQUENCY HEATING USSR OF BOOK ON
~TX:'iRtIG$ AND SE}ff,
- 1 -
FOR Own.I
Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9
A. V. Donskiy and A. A. Frunkin
The book V
Frequency Heating of Dielectrics and Semiconductors b 1 rovodnikov(High
Netushil, and Ye. P. Parini
rgoizdat 236 pages, p? es Maz13.7 A. V.
contains ten chapters, an appendix, ' (ndix, 1950
a bibliography, ,and y N. alphabetical Arubles),
It presents an account of basic phenomena and an alphabetical index.
of dielectrics and semiconductors. Elementary inf t
ng the highg on _ orma of high_frequency i Frequency heating
vacuum-tube oscillators. Oscillator circuits iapp is ble the theory
dielectric heating are discussed, and several industrial equipments
to
Basic relationships for the calculation of vacuum-tube i s, as w
instructions on their utilization, are given. The book isintded for ua bybed.
electrical engineers and production engineers who must deal with high-frequency
equipments for dielectric heating.
Chapter 1 is devoted to the importance of high
-frequency heating of
dielectrics and sc:utconductors in industry. The history of the problem emphasis on the priority of Soviet researchers in this field. The ban
problem is stated,
of industry in which hi-frequency heating is used very briefly are some technologi al characteristics of ehigh-fre hen. heatrgeds
quny
of various-substances (drying of wood, preheating of plastics, high-frequency
heating in the rubber industry, etc.). Plastics, Chapter 2 gives elementary information on electrostatics. The electric
field of a parallel-plate condenser is discussed. Such terms as electric field intensity, breakdown voltage, and energy
ization capacitance,
capacitor are defined and the relations between these . Polar-
of conductors, semiconductors, and dielectrin of an an electric field are
discussed. The concepts of values are given. PolPolarizable and polar molecules in dielectrics are
 Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9
Presented. The relationship between polarization and field intensity is derive,i.
The concept of dielectric constants is outlined. Formulas are given for calcu-.
lsting the energy and energy density of the electric field s is noted.
different nature of polariinzationemi
in a dielectric. conductor The
The charge distribution
s
s in dielectrics and in semiconductor at different stages of polarization
is described.
Chapter 3 discuv3es heating of materials in an alternating electric field.
The liberation of heat in conductors when an electric current flows in them and
the liberation of heat in conductors placed in an alternating electric field are
both discussed. Formulas are given for computing the electrical power converted
to heat in the material; examples are used to illustrate that very little heat
is liberated in conductors within an alternating field because of their very low
resistivity. Transfer of electrical energy from source to load is described and
the concept of skin effect is presented; the dependency of depth of current
penetration upon resistivit;; and frequency is given.
Chapter 3 also includes a discussion of the generation of heat in dielectrics
placed in an alternating electric field. The theory of dielectric losses is
presented in very elementary form. It is indicated that the basic cause of heat
generation within the dielectric is the friction which takes place between polar
molecules and between these molecules and the adjacent stationary particles.
These concepts are illustrated by graphs of t? Q' versus frequency, temperature,
and moisture content for various dielectrics.
placed Finally, Chapter 3 contains a discussion of heat generation in semiconductors
characteristiclofrbothnconductors and field.
dielectrics, energy semiconductors
lossespossess
of e both r kindsies
occur. At low frequencies, a semiconductor behaves like a conductor, while at
high frequencies the dielectric properties become most prominent. The concept
of equivalent electric circuit of a semiconductor is introduced, on the basis
of which formulas are given for calculating conductance, susceptance, effective
resistance, and reactance of semiconductors (g)b,r, and x). By way of illus-
tration, graphs give the dependence of E, tg 6, g, b, r, and x, upon frequency,
moisture content, and te.^peratur e fo_? some semiconductors.
In Chapter 4, instances of nonuniform heating of materials are discussed
and the conditions by which this nonuniformity can be obviated are set forth.
As an example, the distribution of temperature and moisture in non-
homogeneous samples of wood during the drying process is giver-. Using the
graphs of the preceding chapter, the authors demonstrate that, in the case of
transversely alternating wood layers with different initial moisture content,
a greater amount of heat will be generated within layers of 10$ moisture content
than in those having 5% moisture content; i.e., more heat is generated in the
more humid layers, while if the alternating layers contain 15% and 110-50% of
moisture, respectively, more heat is generated within the drier layers. This
is explained by the fact that at 10u moisture content, the curve of.r,.in the
case of spruce, passes throe h a caxir.iwss, and since the specific power p is
proportional tc r, p also reaches a maximum at that moisture content.
The heating in the case of a longitudinal distribution of the material
layers within the electric field is discussed. It is shown that in this
instance the specific power is proportional to the conductivity, and that the
more humid layers are heated to a greater extent.
The effect of an air gap between material and electrode is pointed out.
By simple mathematical computations, the authors show that the existence of an
air gap results in unsatisfactory heating conditions in the case of wood contain-
ing more than 15-20%.% moisture (temperature distribution is inversely pro-
portional to moisture). In high-frequency drying of wood, therefore, the
Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9
 Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9
existence of an air gap between wood and electrode is to be avoided. (Members
of the Electric Heating Section of VNT.TOE did not agree with the authors' con-
tention that it is undesirable-to have an air gap in the operating condenser
when subjecting wood to high-frequency drying.) Heating of anisotropic materials
is discussed. Graphs are given showing the conductivity and effective resistance
for birch in different' directions of the anisotropy axes as a function of
moisture content. It is shown that nonuniform temperature distribution within
the wood in the high-frequency heating process is caused by the heterogeneous
structure of the wood.
Heat generation in materials which fill the condenser in an uneven manner
is considered. Illustrations are given showing the temperature distribution
within bodies of various configuration when placed in condensers of different
shapes. The shape of a condenser producing uniform heating is ascertained.
A discussion follows on nonuniform heating due to formation of standing
waves. The formation of standing waves is explained, and the conditions under
which they occur are stated. The authors recommend that the distance between
the point of supply connection and the most remote point of the dielectric should
not exceed 1/20 of the wave length. If this condition is maintained, the non-
uniformity of the electric field will not exceed 5%. Systems for the compen-
sation of standing waves (by means of parallel supply of the load and connection
of tuned inductances) are given in those instances where, because of production
conditions, high frequency is required in heating dielectrics of large size.
The chapter is concluded by a brief description of dielectric heating in a
cavity resonator when waves of the meter and decimeter hand are used.
Chapter 5 considers the material being heated from the standpoint of
generator load. Formulas are given for calculating effective resistance and re-
actance of the charge depending upon the specific characteristics of the material
and the degree of filling of the condenser by the material being heated. Some
systems for compensating the changes in load parameters in the heating process
are discussed. Numerous systems of electrode arrangements are given: for the
cementing of variously shaped parts, for the heating of films and filaments, for
the drying of thin layers of materials, for the thawing out of soil, for conveyer
heating of materials, etc. Formulas are given for calculating the energy and
power theoretically required for various types of heat-treatment. Graphs are
supplied for determining the heat of fusion and evaporation of various substances
depending on the speed required in the process and weight of the material.
Formulas are given for calculating the power necessary to compensate for heat
losses into the surrounding medium and graphs are given showing the relation
between thermal losses (by convection and by radiation) and surface temperature
of the material. Examples are given at the end of the chapter for computing. the
power required, taking thermal losses into account.
Chapters 6, 7, and 8 are devoted ':o the theory of vacuum-tube oscillators.
Free oscillations in the case of theoretical and actual circuits are considered
and methods of producing damped and undamped high-frequency oscillations (spark,
electric machine, and vacuum-tube generators) are treated.
Construction, operation, and characteristics of electron tubes are described.
Oscillator tubes of various designs air- and water-cooled) and a magnetron used
for the generation of oscillations having a frequency greater than 220 Mc are
discussed.
The operation of a separately excited generator under conditions of first-
and second-order oscillations is discussed. The concept ofiintensity of gener-
ator operating conditions is introduced and systems of parallel slid series plate
supply. are treated. Instructions are given for selection of generator tubes and
design of the generator.
Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9
 Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9
Next, the operation of self-excited generators is considered. Conditions
of self-excitation and various feedback systems are given. In addition the
following topics are discussed: systems for obtaining grid bias, push-pull
operation, oscillators with two tuned circuits, and coupling of tuned curcuits.
Also, resonance curves of two coupled circuits are given for various values of
the coupling coefficient. Generator power supplies are discussed, in particular
the operation of A. N. Larionov's gas-filled rectifier.
In conclusion, some of the operational characteristics of short-wave and
ultrashort-wave generators are very briefly presented.
Chapters 9 and 10 deal with industrial high-frequency heating installations.
Operational characteristics of industrial vacuum-tube generators are discussed.
Methods of matching load and efficiency for generators with one and two tuned
circuits are described. Systems of automatic load matching and automatic
resonance tuning are given.
Systems and descriptions of industrial vacuum-tube generators are then
presented, specifically the following:
1. The high-frequency installation with two GKE-1000 tubes in push-pull
developed by TsIHILEPS (Centrhl Scientific Research Laboratory for the Electrifi-
cation of Industry and of Construction Work) for the preheating of molding
powders; power of 1.5 kw, frequency, 25-35 Mc; the installation makes it possible
to heat 100-120 g of standard molding material up to 120-140 oC within 30-40
seconds.
2. Diagram and description of the installation for the drying of wood,
also developed by TsNILEPS, with two G-45J4 tubes; oscillatory power. of 50 kw;
frequency 333, 476,.nd 666 kc.
Chapter 11, the last chapter, deals with the adjustment and operation of
industrial installations. This chapter covers operations which must be carried
out when adjusting and testing the installation and putting it into operation.
Methods of eliminating parasitic oscillations are discussed. Descriptions are
given of instruments and methods of measuring used in adjustments; e.g., measure-
ment of high-frequency current, voltage, and power. Methods of reducing inter-
ference to radio reception are discussed, and standards for permissible industrial
radio interference caused by industrial high-frequency installation are cited.
The chapter is concluded by rules for maintenance and safety procedures.
The appendix contains an example showing the calculations involved in
designing a 1.6-kw vacuum-tube generator for the heating of molding powders.
The book is undoubtedly of interest, since it is the first attempt to present
in a systematic manner the theoretical and experimental data presently available
in the field of dielectric heating.
Pamphlets and articles. published recently on high-frequency heating of
dielectrics and semiconductors deal only with specific and isolated phases of
this extensive and complex problem. In this book, an attempt is made to provide
a general review of all available data. However, apparently because of its limited
size, the book covers only a small portion of data (mostly experimental) accumu-
lated up to now by the personnel of various industrial enterprises and scientific
research establishments.
Nevertheless, the task undertaken by the authors.-- to present in the
simplest possible mnnner the basic phenomena underlying the high-frequency heat-
ing of nonmetallic materials, and to outline the functioning and the elements of
design of vacuum-tube generators of high-frequency oscillations, -- has been for
the most part fulfilled.
Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9
 Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9
STAT
There is some doubt as to whether the material of chapters 2, 3, and 4
has been presented in a sufficiently comprehensive manner. These chapters deal-
ing with the fundamentals of dielectric heating are schematic and formally
mathematical in presentation. In striving for an elementary explanation of these
phenomena, the authors have -very much oversimplified their physical meaning.
Although the preface states that production peculiarities and engineering
economic factors of high-frequency heating are to be treated by the authors in
separate publications, the economic aspects of high-frequency heating should have
been giver. definite consideration in this book. At present, there is an excess-
ive enthusiasm for dielectric heating, and large expenditures are frequently
made on researches where the prospect of success is obviously nonexistent.
Hence, there should have been included in the book (which had a sufficiently
large printing and undoubtedly will reach a wide circle of readers) an objective
evaluation, from the economic standpoint, of the various technological applica-
tions of high-frequency heating.
In describing generators with a single tuned circuit, the authors assert
(page 182) that over-all efficiency of the installation may reach 60-70%. Such
figures might mislead the reader and convey a false impression as to the actual
efficiency of the installation. As a matter of fact, the efficiency of industrial
installations at present is only 35-40%. The authors neglect heat losses from
the material being heated, and clearly underestimate losses in filament and grid
circuits and in the rectifier.
In describing systems of industrial vacuum-tube generators, the authors
merely discuss installations developed by TsNILEPS, without mentioning whether
they have been put into production.
At the same time, the authors fail to describe installations Lg-3 and LGD-10
which have been accepted for mass production, or the type GS-48 installation for
the drying of wood which is now manufactured by the Plant imeni Voroshilov.
In conclusion, it crust be admitted that in spite of the short-comings noted,
the bock is undoubtedly useful not only to those for whom it is intended, but
also to those concerned with planning, building, and reasearch in the field of
dielectric heating. Its publication is timely.
Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150374-9