Electrical equipment of industrial enterprises and installations. Workshop on analysis and diagnostics of financial and economic activities of an enterprise (RUB 250.00)

Chercher 10.03.2020
Litigation

Litigation

AND FOOD OF THE RUSSIAN FEDERATION

MOSCOW STATE AGRICULTURAL ENGINEERING UNIVERSITY NAMED AFTER V.P.GORYACHKINA

Zimin N.E., Trishkina L.V.

ANALYSIS OF ECONOMIC RESULTS,

FINANCIAL STATUS AND ASSESSMENT

OPERATION EFFICIENCY

for course work

in the discipline “Technical and economic analysis of enterprise activities”

Moscow 1998

UDC 658.012(075.8)

Methodological recommendations for course work in the discipline “Technical and economic analysis of enterprises’ activities.” Intended for students of specialty 060821 - economics and management at technical service enterprises of all forms of education.

Compiled by: N.E. Zimin, L.V. Trishkina.M.; MSAU, 1998. 73 p.

Table 20, library 19 title.

Reviewer: Patskalev A.F. (VNIETUSKH)

 Moscow State

agricultural engineering university

named after V.P. Goryachkin, 1998.

I. General provisions

1.1. Goals and objectives

Coursework, being important element training of highly qualified specialists, pursues the following goals:

    secure theoretical knowledge acquired by students while studying economic disciplines;

    master methodology for conducting technical and economic analysis of enterprises’ activities;

    develop students have the skills to work independently, collect and process economic information, conduct research based on actual data on the activities of enterprises;

    prepare a basis for performing the analytical part of graduation projects.

Coursework includes the following mandatory elements :

    Title page.

    Annotation.

    Introduction.

    Initial data.

    Analytical part.

6.1. Analysis economic results.

6.1.1. Analysis of balance sheet profit.

6.1.2 * Factor analysis of profit from the sale of goods, products, works and services.

6.1.3*. Analysis of profit from other operating income and expenses.

6.1.4*. Analysis of profit from non-operating income and expenses.

6.1.5. Analysis of the use of profits.

6.2. Analysis of the property and financial position of the enterprise.

6.2.1. Assessment of property status.

6.2.2. Valuation of capital invested in property.

6.2.3. Analysis of the enterprise's provision with its own working capital and assessment of the influence of factors on the magnitude of their change.

6.2.4. Analysis of the efficiency of using working capital.

6.2.5. Analysis of financial stability indicators.

6.2.6. Assessment of solvency and liquidity.

6.3. Assessing the efficiency of an enterprise.

6.3.1. Analysis of profitability indicators.

6.3.2. Assessing the efficiency of using enterprise resources.

7. Conclusion.

8. List of used literature.

9. Application.

1.3. Initial data

According to the curriculum for training economists-managers, coursework is completed after the second stage of practical training. Therefore, the main sources of data for analysis are the department’s assignments performed by students when compiling and submitting relevant reports on practice. These include: Form No. 1 “Balance Sheet of the Enterprise”, Form No. 2 “Profit and Loss Statement”, Form No. 5 “Appendix to the Balance Sheet” and others, which are given in the text of these guidelines for performing the analytical part of the work.

The student has the right to complete coursework based on materials from the enterprise, using the example of which he plans to write a diploma project. For students of correspondence and other forms of study, it is possible to complete coursework using information from the enterprises where they work. In all cases, the decision made is agreed with the course supervisor.

Academic discipline“Electrical equipment of enterprises and civil buildings” is a special study that involves the study of electrical equipment of machine-building enterprises: metalworking machines, automatic lines, general industrial mechanisms (cranes, elevators, flow-transport systems, compressors, pumps, fans), electrical equipment of electrothermal installations and welding installations, electrical equipment of civil buildings.

Main books:

Zimin E. N. and others. Electrical equipment industrial enterprises and installations / E. N. Zimin, V. I. Preobrazhensky I. I. Chuvashov: Textbook for technical schools. - 2nd ed., revised. and additional - M.; Energoizdat, 1981.—552 p.

The book outlines the most common and common electrical equipment issues technological installations, machines and machines of industrial enterprises. Examples are given for the calculation and selection of engines and other electrical equipment. Given electrical circuits control of general industrial installations. The first edition was published in 1968 under the title “Electrical equipment of industrial enterprises and installations in mechanical engineering.” The 2nd edition, completely updated, covers electrical equipment and installations of electrical engineering enterprises.

The book discusses basic electrical equipment, automation issues, electrical circuits of electrothermal and electric welding installations, hoisting and transport machines and mechanisms, metalworking machines and machines, pumps, compressors, fans and other installations.

Download the book Zimin E. N. Electrical equipment of industrial enterprises and installations (djvu, zip, 7.68 MB) - download book

Kharizomenov I.V. Electrical equipment and electrical automation of metal-cutting machines. M., “Mechanical Engineering”, 1975. 264 p.

The book lays out the basics electrical equipment machines, including latest achievements domestic and foreign machine tool industry. Particular attention is paid to electrical automation of machine tools as the main way technical progress in machine tool industry. Studying the electrical equipment of machine tools is necessary to understand modern means and opportunities in the field of automation of modern machines, automatic lines and factories. Without this knowledge, it is impossible to design a new machine or explain the operation of a modern machine with automated system management.

Download the book Kharizomenov I.V. Electrical equipment and electrical automation of metal-cutting machines (djvu, zip, 4.61 mb) - download book

Automation systems design technological processes: Reference Guide/A. S. Klyuev, B. V. Glazov, A. Kh. Dubrovsky, A. A. Klyuev; Ed. A. S. Klyueva. — 2nd ed., revised. and additional - M.: Energoatomizdat, 1990, - 464 p.

Systematized information and regulatory materials, necessary for the development of process automation projects. The second edition reflects changes in regulatory and technical documents, takes into account the requirements for improvement and reduction of labor intensity installation work. The first edition was published in 1980. For engineers and technical workers involved in the design, installation and operation of automation equipment and systems.

Download the book Designing Process Automation Systems: A Reference Guide. A. S. Klyuev (djvu, zip, 7.01 mb) - download book

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Electrical equipment of electrothermal installations:

Electric industrial furnaces. In 2 parts. Part 1. A. D. Svenchansky. Electric resistance furnaces. Ed. 2nd, revised M., “Energy”, 1975, 384 p.

The book provides the basics of heat transfer theory necessary for thermal calculations of electric resistance furnaces, their design features, drives, auxiliary mechanisms and equipment, issues of thermal and electrical calculations and rational operation of resistance furnaces. In addition, data on modern electric furnace materials are presented, as well as the basics of vacuum technology and temperature measurement technology. The book is intended as a textbook for students of electrical engineering universities and can also serve as a guide for engineering and technical workers.

Download the book Electric industrial furnaces. A. D. Svenchansky (djvu, zip, 16.98 MB) - download book

Electrotechnological industrial installations / I. P. Evtyukova, L. S. Katsevich, N. M. Nekrasova, A. D. Svenchansky; Edited by A. D. Svenchansky. - M.: Energoizdat, 1982. - 400 p.

The main types of electrical technological installations are described, with the main attention paid to those that are most widespread in industry and are large consumers of electricity, as well as those in which new electrical technological processes are implemented. Intended as a teaching aid for students studying in the specialty “Power supply of industrial enterprises, cities and Agriculture", in addition, may be useful to industrial workers designing and operating electrical installations.

Download the book Electrotechnological industrial installations. A. D. Svenchansky (pdf, zip, 16.98 MB) - download book

Electrical equipment of metal-cutting machines:

Ignatov V. A. et al. Electrical equipment of modern metal-cutting machines and processing complexes: Textbook. for vocational schools/V. A. Ignatov, V. B. Rovensky, R. T. Orlova. - M.: Higher. school, 1991. - 96 p.

The book provides information about automated electric drive, various engines, relay-contact and non-contact control equipment, protection and automation of machine tools, issues of program control of machine tools from a computer are considered, information is given on the installation, adjustment and operation of various electrical equipment, as well as on safety measures during their maintenance. The textbook can be used to vocational training workers in production.

Download the book Ignatov V. A. et al. Electrical equipment of modern metal-cutting machines and processing complexes (djvu, zip, 2.98 MB) - download book

Electrical equipment for general industrial installations:

Klyuchev V.I., Terekhov V.M. Electric drive and automation of general industrial mechanisms. - Energy, 1980. - 360 p.

The book outlines general issues electric drive and automation of operating modes of typical general industrial mechanisms of continuous and cyclic action. General provisions supplemented by analysis specific examples diagrams of electric drives of mechanisms of various machines, installations and technological complexes— cranes, lifts, excavators, conveyors, dredgers, etc.

In this book, intended as a textbook, the authors sought to reflect the issues as completely as possible. to be covered when delivering lectures in accordance with the current program. Both the content and the method of presentation of the materials in this book reflect the practice of repeatedly reading this course to students of the specialty “Electric drive and automation of industrial installations” at MPEI.

Download the book Klyuchev V.I., Terekhov V.M. Electric drive and automation of general industrial mechanisms (djvu, zip, 4.18 mb) - download book

Karpov F.F., V.N. Kozlov, O.G. Loodus. Automation pumping units. M. Gosenergoizdat, 1961, 48 p.

The purpose of this book is to familiarize readers with some simple electrical automation circuits for pumping units that can find application in one or another sector of the national economy. The book does not pretend to be a systematic presentation of the principles of constructing circuits. It also doesn't have detailed descriptions used factory-made equipment. To clarify it technical characteristics you need to use the appropriate catalogs based on the explanations that are provided with the diagrams.

Download the book Karpov F.F., V.N. Kozlov, O.G. Loodus. Automation of pumping units (djvu, zip, 4.18 MB) - download the book

Cranes and elevators of industrial enterprises. Directory. Ushakov P.N., Brodsky M.G.M., “Metallurgy”, 1974. 352 p.

In accordance with the regulations on cranes and elevators and state standards, interdepartmental instructions consider the rules for safe work with cranes and conditions safe operation elevators. Intended for engineering and technical workers involved in the design, manufacture, installation and operation of load-lifting cranes.

Download the book Cranes and elevators of industrial enterprises. Directory. Ushakov P. N. (djvu, zip, 10.66 mb) - download book

Electrical equipment for cranes at metallurgical enterprises. 3rd ed., revised. and additional Raputov B. M. - M.: Metallurgy. 1990. 272 ​​p.

The electrical equipment of cranes of metallurgical enterprises is considered: crane electric motors of direct and alternating current and their operating modes, electrical control and protection equipment, crane power supply, modern systems and control circuits using contact-relay and contactless equipment. Features of electrical equipment of cranes are given general purpose and special crashes working at metallurgical enterprises. Methods are given for calculating the power and selecting the electric motors of these cranes, choosing crane electrical equipment, etc. Material on the operation and repair of crane electrical equipment is provided.

Download the book Electrical equipment for cranes at metallurgical enterprises. Raputov B. M. (djvu, zip, 3.39 mb) - download book

Topic 2. Diagnostic normative models

Question 2.5. Types of financial and economic diagnostic models

Zimin N.E. Analysis and diagnostics of the financial condition of enterprises: Textbook. village – M.: IKF “EKMOS”, 2002. – 240 p. (P.95-99)

Chapter 4. Express diagnostics of financial condition

3. Assessment of financial condition rating

Financial stability, solvency and other characteristics financial condition, based on diagnostic results using financial statements enterprises must be supplemented with information about its rating.

The financial condition of an enterprise determines its competitiveness, as well as its potential in business cooperation and is a guarantor of the realization of interests for all participants in economic relations (the enterprise and its partners). Therefore, the financial condition must not only be characterized by a qualitative side, but also have a quantitative dimension. The latter can be implemented using a rating assessment of financial condition, based on the theory of financial analysis of enterprises in the sphere of material production in conditions of market relations.

Rating is a method comparative assessment activities of several enterprises in an industry, region or competitors. The rating is based on a generalized description of enterprises according to a certain system of indicators reflecting their financial condition. The final rating indicator reflects the results of comparing enterprises for each indicator of financial condition with a conditional reference enterprise that has the best results. In this case, the reference point is not the subjective assumptions of experts or judgments on the dynamics of individual indicators, but the highest results from the entire set of subjects being compared that have developed in real market competition.

The standard of comparison is the simulated most successful competitor, who has the best all indicators.

Standardized indicators j of the enterprise.

  • For each analyzed enterprise, the value of its rating assessment is determined by the formula
  • Enterprises are ordered (ranked) in descending order of the rating value.
  1. Indicators for assessing profitability (profitability) economic activity:
    • overall profitability enterprises – balance sheet profit
      for 1 rub. assets;
    • net profitability enterprises – net profit per
      1 rub. assets;
    • profitability equity– net profit per 1 rub. own capital;
    • overall profitability production assets- balance sheet profit to the average value of production assets and
      working capital in inventory.
  2. Indicators for assessing management effectiveness:
    • net profit per 1 rub. total product sales volume;
    • profit from product sales for 1 rub. total sales volume
      products;
    • gross profit from all sales per 1 rub. volume of all
      products;
    • profit from sales per 1 rub. volume of all sales.
  3. Indicators for assessing business activity:
    • return on all assets - revenue from sales of products
      1 rub. assets;
    • return on fixed assets - revenue from sales of products for
      1 rub. fixed assets;
    • turnover revolving funds– revenue from product sales for 1 rub. working capital;
    • inventory turnover - revenue from sales of products for
      1 rub. inventories and costs equivalent to inventories;
    • turnover accounts receivable– revenue from
      product sales for 1 rub. accounts receivable;
    • turnover is the most liquid assets– revenue from
      product sales for 1 rub. the most liquid assets;
    • return on equity capital – revenue from sales of products per 1 ruble. own capital;
    • return on borrowed capital – revenue from product sales
      for 1 rub. borrowed capital.

4. Indicators for assessing liquidity and market stability:

    • current ratio – working capital for 1 rub. urgent obligations;
    • absolute liquidity ratio –- cash, settlements and other assets for 1 rub. urgent obligations;
    • permanent asset index – fixed assets and other non-current assets to equity;
    • autonomy coefficient – ​​own funds per 1 rub. balance sheet currencies;
    • provision of inventories with own working capital - own working capital per 1 rub. inventories and costs.

5. Valuation indicators on the securities market:

    • earnings per share – ratio net profit minus dividends on preferred shares to the total number of ordinary shares;
    • share value - the ratio of share price to earnings per share;
    • profitability of a share - the ratio of the dividend per share to the market price of the share;
    • dividend yield - the ratio of the dividend per one
      share to earnings per share;
    • stock quote ratio – market price ratio
      shares to the book price of the share.

The versatility of the considered methodology lies in the fact that with its help it is possible to obtain a quantitative answer not only to assess the financial condition of the enterprise, but also to profitability, business activity, and production management efficiency. The complexity of rating diagnostics is determined by the corresponding set of indicators of financial and economic activity and production activities enterprises. This provides a unique opportunity to satisfy the needs of any user of diagnostic results. In this case, correction of the list of indicators is necessary. For example, when assessing financial condition, the fourth group of indicators can be supplemented with coefficients for increasing solvency or its loss, which are recommended by the official methodology.

The considered algorithm for obtaining a financial condition rating can be used to compare enterprises in any industry in the sphere of material production and be used in inter-industry comparisons. In this case, diagnostics can be carried out on the balance sheet date or over time.

In the first case, the initial indicators can be defined as growth or gain indices: data at the end of the period are divided by the indicator values ​​at the beginning of the period, or the difference between them is divided by the indicator values ​​at the beginning of the period. In this case, it is possible to use the average values ​​of indicators for the reporting period and previous periods. Thus, an assessment can be obtained not only of the current state of the enterprise on a certain date, but also an assessment of its efforts and capabilities to change this state over time, which allows for a more reasonable prediction of the real future.

print version

PREFACE

This book discusses basic electrical equipment, automation issues, electrical circuits of electrothermal and electric welding installations, hoisting and transport machines and mechanisms, metalworking machines and machines, pumps, compressors, fans and some other installations that have become widespread in industrial electrical engineering enterprises. The book was written in accordance with the program of the subject “Electrical equipment of industrial enterprises and industry installations” for secondary vocational students educational institutions.

The book does not include material only on the section of the “Electrical Lighting” program, for which there is a separate tutorial. Compared to the first edition, published in 1968 under the title “Electrical equipment of industrial enterprises and installations in mechanical engineering,” the book’s material has been revised and updated taking into account the latest achievements and development trends in the field of electrical equipment and automation of industrial production.

The presentation is based on the readers' knowledge of the subjects " Theoretical basis electrical engineering”, “Electrical machines and transformers”, “Fundamentals of industrial electronics”, “Fundamentals of automation and computer technology”, “Electric drive” and “Fundamentals of industry technology”.

INTRODUCTION

Electrification of the national economy of the USSR is the basis for building the economy of a communist society and developing the country's productive forces. Electrification ensures the fulfillment of the task of broad, comprehensive mechanization and automation of production processes, which makes it possible to increase the growth rate of social labor productivity, improve product quality and facilitate working conditions. Based on the use of electricity, technical re-equipment of industry is being carried out, the introduction of new technological processes and the implementation of fundamental reforms in the organization of production and its management. Therefore, in modern technology and the equipment of industrial enterprises, the role of electrical equipment is great, i.e., the set of electrical machines, apparatus, instruments and devices through which transformation is carried out electrical energy other types of energy and automation of technological processes is ensured.

Electrical mechanical engineering is one of the leading branches of the mechanical engineering industry. The process of manufacturing an electric machine consists of operations in which a variety of technological equipment is used. At the same time, the bulk of modern electrical machines are manufactured using mass flow production methods. The specificity of electrical engineering lies mainly in the presence of such processes as the manufacture and installation of windings of electrical machines, for which non-standardized equipment is used, usually manufactured by the electrical engineering plants themselves*

For the most part, the technological equipment and electrical equipment of electrical machine-building plants are typical for mechanical engineering in general. Electrical mechanical engineering is characterized by a variety of technological processes that use electricity: foundry, welding, processing of metals and materials by pressure and cutting, heat treatment, etc. Electrical mechanical engineering enterprises are widely equipped with electrified lifting and transport mechanisms, pumping, compressor and fan units. Automation affects not only individual units and auxiliary mechanisms, but increasingly their entire complexes, forming fully automated production lines and workshops.

Of primary importance for production automation are multi-motor electric drives and electrical controls. The development of electric drives follows the path of simplifying mechanical transmissions and bringing electric motors closer to the working parts of machines and mechanisms, as well as the increasing use of electrical speed control of drives. Complete thyristor converter devices are being widely introduced. The use of thyristor converters not only made it possible to create highly economical adjustable electric drives DC, but also opened up great opportunities for the use of frequency regulation of AC motors, primarily the simplest and most reliable asynchronous motors with a squirrel-cage rotor. Are becoming more widespread the latest tools electrical automation of technological installations, machines and mechanisms based on semiconductor technology, highly sensitive instrumentation and control equipment, contactless sensors and logic elements. The scope of application of program control of technological objects with the recording of the program on paper or magnetic tape is expanding. Electronic computers are increasingly used to control technological processes. IN modern conditions operation of electrical equipment requires deep and versatile knowledge, and the tasks of creating a new or modernizing an existing electrified technological unit, mechanism or device are solved by the joint efforts of technologists, mechanics and electricians. Requirements for electrical equipment arise from technological data and conditions. Electrical equipment cannot be considered in isolation from the structural and technological features electrified object, and vice versa.

Therefore, specialists in the field of electrical equipment of industrial enterprises must be well acquainted with both the electrical part and the basics of technological processes and the designs of electric heating and electric welding installations, metalworking machines and machines, hoisting and transport mechanisms, etc.

Electrical equipment of industrial enterprises and installations is designed, installed and operated in accordance with the Rules for the Construction of Electrical Installations (PUE) and other governing documents.

Chapter first

ELECTRICAL EQUIPMENT OF ELECTRIC HEATING INSTALLATIONS

1-1. GENERAL INFORMATION ABOUT ELECTROTHERMAL INSTALLATIONS

Electric heating is widely used in electrical engineering enterprises in the production of shaped castings from metals and alloys, heating of workpieces before pressure treatment, heat treatment of parts and assemblies of electrical machines, drying insulating materials etc.

An electrothermal installation (ETU) is a complex consisting of electrothermal equipment (an electric furnace or an electrothermal device in which electrical energy is converted into heat), and electrical, mechanical and other equipment that ensures the implementation of the work process in the installation. Electrothermal equipment is very diverse in principle of operation, design and purpose. In the most general form, all electric furnaces and electrothermal devices can be divided by purpose into melting furnaces for smelting or overheating molten metals and alloys and thermal (heating) furnaces and devices for heat treatment of metal products, heating materials under plastic deformation, drying products, etc.

According to the method of converting electrical energy into heat, they distinguish, in particular, furnaces and resistance devices, arc furnaces, induction furnaces and devices.

Electric furnaces and electrothermal resistance devices use the release of heat and electric current as it passes through solid and liquid bodies. Electric furnaces of this type are primarily designed as indirect heating furnaces. The conversion of electricity into heat occurs in solid heating elements, from which heat is transferred to the heated body by radiation, convection and thermal conductivity , or in a liquid coolant - molten salt, into which the heated body is immersed, and heat is transferred to it by convection and thermal conductivity. Resistance furnaces are the most common and diverse type of electric furnaces.

Resistance melting furnaces are used primarily in the production of castings from low-melting metals and alloys. Thermal furnaces are used for heat treatment of metals and drying of materials and products. Electrothermal resistance devices operate on the principle of direct heating: the body to be heated directly serves as a conductor of the body and heat is generated in it. The operation of electric arc melting furnaces is based on the release of heat in an arc discharge. In an electric arc, high power is concentrated and a temperature of over 3500° C develops. In indirectly heated arc furnaces, the arc burns between the electrodes, and heat is transferred to the molten body mainly by radiation. Furnaces of this kind are used in the production of shaped castings from non-ferrous metals, their alloys and cast iron. In direct heating arc furnaces, one of the electrodes is the molten body itself. These furnaces are designed for smelting steel, refractory metals and alloys. Direct arc furnaces, in particular, produce the majority of steel for shape casting. In induction furnaces and devices, heat in an electrically conductive heated body is released by currents induced in it by an alternating electromagnetic field. Thus, direct heating takes place here. An induction furnace or device can be considered as a kind of transformer, in which the primary winding (inductor) is connected to an alternating current source, and the heated body itself serves as the secondary winding. Induction melting furnaces are used in the production of castings, including shaped ones, from steel, cast iron, non-ferrous metals and alloys. Induction heating furnaces are used for heating workpieces for plastic deformation and for carrying out various types of heat treatment. Induction thermal devices are used for surface hardening and other specialized operations involving numbers and auxiliary letters. The first main letter indicates the heating method, for example: D - arc, I - induction, C - resistance. For melting furnaces, the second main letter of the designation determines the base metal for which the furnace is intended for melting: aluminum and its alloys; M - copper and its alloys (cromel brass), brass; O - tin, lead, C - steel and heat-resistant* alloys; Ch - cast iron, etc. The third main letter characterizes the most important design feature of a melting furnace, for example, for arc furnaces: P - with a rotary arch; B - drum; for induction furnaces: K - channel, T - crucible; for resistance furnaces: T - crucible, K - chamber, B - drum. A fourth (auxiliary) letter can also be added, for example the letter M, to designate a mixer. The number after the letter designation for most melting furnaces indicates the furnace capacity in tons.

In thermal resistance furnaces, the second main letter characterizes the main design feature: A - rotary; B - drum; B - bathroom; D - with a retractable hearth; K—conveyor; N - chamber; R - roller table; T - pusher; Ш - shaft, etc. The third main letter for these furnaces shows the nature of the environment in the furnace space: A - nitriding; 3 - protective; O - oxidative (air); C - salt, saltpeter; C—cementation, etc. The letters are followed by the dimensions of the working space in decimeters. For all furnaces, the maximum temperature in hundreds of degrees Celsius (°C) is indicated through a fraction. For units of several ovens, the unit designation corresponds to the designation of the first oven with the addition of the letter A, the denominator corresponds to the temperature of the last oven of the unit. To the notation

For furnaces with cooling chambers, the letter X and a number are added indicating the length of the chamber in decimeters.

Electrothermal installations, as a rule, are powered by alternating current (except for installations of vacuum arc furnaces, which require D.C.). In relation to ensuring the reliability of power supply, according to the PUE, ETUs mainly belong to electrical receivers of the 2nd or 3rd category,

ETU component electrical equipment includes: furnace transformers and autotransformers; converting units (for installations of furnaces and electrothermal devices, in which the conversion of electrical energy into thermal energy occurs at a frequency other than 50 Hz); switching and protective devices at the ETU input; ETU conductors—power electrical circuits connecting furnaces (electrothermal devices) with other electrical equipment; automatic regulators of the thermal regime of the furnace (devices); electric drives of auxiliary mechanisms of the ETU; boards, consoles and control stations. Below we briefly discuss the main types of ETS (for more details, see).

1-2. INSTALLATIONS OF RESISTANCE FURNACES

Design of resistance furnaces. The design of resistance furnaces is significantly influenced by the nature of the operation and the characteristics of loading and unloading heated materials, as well as temperature conditions, the presence or absence of an artificial atmosphere in the working space of the furnace. Based on the loading method and the nature of the work over time, furnaces are distinguished between periodic (catch) and continuous (methodical) operation. In a batch furnace, after loading, the heated body does not change its position during the entire time of heat treatment, i.e. until the moment of unloading. In a continuous furnace, heated products are loaded from one end of the furnace, gradually moved along its length, warming up to a given temperature, and released from the other end of the furnace. Such furnaces are used, in particular, in automatic production lines.

In Fig. Figure 1-1 schematically shows some of the main types of designs of thermal resistance furnaces: charge and methodical. The chamber furnace (Fig. 1-1, a) among intermittent furnaces is the simplest and at the same time universal. Its rectangular body 2 is made in the form of a chamber with a fire-resistant and heat-protective lining placed in a metal casing. The oven is loaded and unloaded through an opening in the front wall, closed by a door /. Small stoves are installed on legs for ease of loading, large stoves are installed directly on the floor. Heating elements 3 are located in the hearth and on the side walls of the oven, less often on its roof (for very large ovens, on the back wall of the oven and on the door). The bottom heating elements are covered with heat-resistant plates, on which the products are laid. Furnace doors are usually made with lifting ones, for small furnaces - with a manual or foot drive, for larger ones - with an electric drive.

The shaft furnace (Fig. 1-1.6) is a round, square or rectangular shaft. The furnace body 2 is buried in the ground and covered with a lid 4 with a shutter and an electric drive. Heating elements 3 are suspended on the side walls of the furnace. In such furnaces, heat treatment is carried out, for example, on long shafts. Some shaft furnaces have two or three thermal zones to ensure uniform heating of long products. In a bell-type furnace (Fig. 1-1, c), a removable housing 2 (cap) of cylindrical or rectangular shape with heating elements 3 on the side walls and a heat-resistant muffle 5 are installed by crane. The load is also placed using a crane on the stand under 6 of the furnace (with raised hood and muffle). The heating elements are powered using flexible cables and electrical connectors (plug connectors). Typically, several stands are served by one hood. Upon completion of heating, the bell is a type of chamber furnace. It is used for heat treatment and annealing of very large products. Here chamber 2 has no bottom and stands on columns, and the retractable one under 7 is mounted on a trolley with electric rollers or a winch. For loading and unloading, the door / is opened and the trolley moves out from under the chamber. The arrangement of the heating elements is the same as in a conventional chamber oven. A salt electrode bath (Fig. 1-1.0) is a metal or ceramic bath 5 filled with salt 10, into which electric heaters (electrodes) P are lowered. The part of the bath in which the electric heaters are located is separated from the working part by a partition. The bath is placed in housing 2 and covered on top with an umbrella 9. To start the bath (heat the salt), a special immersion electric heater is used. Salt baths provide quick and uniform heating of products placed in molten salt.

They are used, in particular, for heating for hardening and tempering of tools. Continuous furnaces are characterized by the presence of a transport mechanism that can be different ways. In a pusher oven (Fig. 1-1, e), which has a long rectangular chamber 2 with heaters 3, products on or without pallets 12 are periodically pushed along the guides or rollers of the oven feed using a pusher mechanism located in front of the loading door / mechanism with an electric or hydraulic drive. During pushing, the loading/unloading doors of the oven are opened. The advantages of a pusher furnace are primarily determined by the reliability of operation, since the pusher mechanism is located outside the furnace, as well as the ability to process large mass products.

The conveyor oven (Fig. 1-1, g) is a long chamber 2 with heaters 3 and doors and 1. The transport mechanism of the oven is a chain conveyor 13, the endless web of which consists of a woven metal mesh or chain links. The conveyor chain is stretched between the driving and driven drums and is driven by an electric drive through a transmission mechanism and the driving drum. The drums can be located inside or outside the oven. In the first case, there is less heat loss; in the second, the reliability of the furnace operation increases, and its loading and unloading is simplified. The drum furnace (Fig. 1-1, h) has in the chamber 2 heaters 3 heat-resistant drum (muffle) 14 Sarchimedean spiral. When the drum rotates using an electric drive, the products roll in the drum, gradually moving from the loading device 15 to the unloading point. Such furnaces are used, for example, for hardening small parts that do not have sharp edges. Then from the discharge end of the drum the parts enter the quenching tank 16.

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