Conditions, aspects and stages of automation of TGV systems. Mukhin-automation of heat and gas supply and ventilation systems. Sensors are one of the most important functional elements of any control system. Their properties and characteristics often largely determine p

Technological parameters, objects of automatic control systems. Sensor and transducer concepts. Displacement transducers. Differential and bridge circuits for connecting sensors. Sensors of physical quantities - temperature, pressure, mechanical forces. Monitoring of media levels. Classification and diagrams of level gauges. Methods for controlling the flow rate of liquid media. Variable level and variable differential pressure flowmeters. Rotameters. Electromagnetic flowmeters. Implementation of flow meters and scope.Methods for controlling the density of suspensions. Manometric, weight and radioisotope density meters. Control of the viscosity and composition of suspensions. Automatic granulometers, analyzers. Moisture meters for enrichment products.

7.1 General characteristics of control systems. Sensors and Transducers

Automatic control is based on continuous and accurate measurement of input and output technological parameters of the beneficiation process.

It is necessary to distinguish between the main output parameters of the process (or a specific machine) that characterize the ultimate goal of the process, for example, the qualitative and quantitative indicators of processed products, and intermediate (indirect) technological parameters that determine the conditions for the process, the operating modes of the equipment. For example, for the process of coal beneficiation in a jig, the main output parameters can be the yield and ash content of the produced products. At the same time, these indicators are influenced by a number of intermediate factors, for example, the height and looseness of the bed in the jig.

In addition, there are a number of parameters that characterize the technical condition of technological equipment. For example, the temperature of the bearings of technological mechanisms; parameters of centralized liquid lubrication of bearings; condition of reloading nodes and elements of flow-transport systems; the presence of material on the conveyor belt; the presence of metal objects on the conveyor belt, the levels of material and slurry in containers; duration of work and downtime of technological mechanisms, etc.

A particular difficulty is caused by automatic on-line control of technological parameters that determine the characteristics of raw materials and processing products, such as ash content, material composition of ore, degree of opening of mineral grains, grain size and fractional composition of materials, degree of oxidation of the surface of grains, etc. These indicators are either controlled with insufficient accuracy or not controlled at all.

A large number of physical and chemical quantities that determine the modes of processing of raw materials are controlled with sufficient accuracy. These include the density and ionic composition of the pulp, volumetric and mass flow rates of technological streams, reagents, fuel, air; food levels in machines and apparatus, ambient temperature, pressure and vacuum in apparatus, food moisture, etc.

Thus, the variety of technological parameters, their importance in the management of enrichment processes require the development of reliably operating control systems, where the on-line measurement of physicochemical quantities is based on a variety of principles.

It should be noted that the reliability of the parameter control systems mainly determines the operability of the automatic process control systems.

Automatic control systems are the main source of information in production management, including in automated control systems and process control systems.

Sensors and Transducers

The main element of automatic control systems, which determines the reliability and performance of the entire system, is a sensor that is in direct contact with the controlled environment.

A sensor is an automation element that converts a monitored parameter into a signal suitable for entering it into a monitoring or control system.

A typical automatic control system generally includes a primary measuring transducer (sensor), a secondary transducer, an information (signal) transmission line and a recording device (Fig. 7.1). Often, the control system has only a sensitive element, a transducer, an information transmission line and a secondary (recording) device.

The sensor, as a rule, contains a sensitive element that senses the value of the measured parameter, and in some cases converts it into a signal convenient for remote transmission to a recording device, and, if necessary, to a control system.

An example of a sensing element would be the diaphragm of a differential pressure gauge that measures the pressure difference across an object. The movement of the diaphragm caused by the force from the pressure difference is converted by an additional element (transducer) into an electrical signal, which is easily transmitted to the recorder.

Another example of a sensor is a thermocouple, where the functions of a sensing element and a transducer are combined, since an electrical signal is generated at the cold ends of the thermocouple, which is proportional to the measured temperature.

More details about sensors of specific parameters will be described below.

Transducers are classified into homogeneous and non-homogeneous. The first have the same physical nature of the input and output values. For example, amplifiers, transformers, rectifiers - convert electrical quantities into electrical ones with other parameters.

Among the heterogeneous ones, the largest group is made up of converters of non-electrical quantities into electrical ones (thermocouples, thermistors, strain gauges, piezoelectric elements, etc.).

According to the type of output value, these converters are divided into two groups: generator ones having an active electrical value at the output - EMF and parametric ones - with a passive output value in the form of R, L or С.

Displacement transducers. The most widespread are parametric transducers of mechanical movement. These include R (resistor), L (inductive) and C (capacitive) converters. These elements change in proportion to the input displacement the output value: electrical resistance R, inductance L and capacitance C (Fig. 7.2).

An inductive transducer can be made in the form of a coil with a mid-point tap and a plunger (core) moving inside.

The converters under consideration are usually connected to control systems using bridge circuits. A displacement transducer is connected to one of the bridge arms (Fig. 7.3 a). Then the output voltage (U out) taken from the tops of the A-B bridge will change when the working element of the converter is moved and can be estimated by the expression:

The supply voltage of the bridge (U feed) can be constant (with Z i = R i) or alternating (with Z i = 1 / (Cω) or Z i = Lω) current with frequency ω.

Thermistors, strain and photoresistors can be connected to a bridge circuit with R elements, i.e. transducers whose output signal is a change in the active resistance R.

A widely used inductive converter is usually connected to an alternating current bridge circuit formed by a transformer (Fig. 7.3 b). The output voltage in this case is allocated on the resistor R, included in the diagonal of the bridge.

A special group is made up of widely used induction converters - differential-transformer and ferro-dynamic (Fig. 7.4). These are generator converters.

The output signal (U out) of these converters is generated in the form of an alternating current voltage, which eliminates the need to use bridge circuits and additional converters.

The differential principle of the formation of the output signal in the transformer converter (Fig. 6.4 a) is based on the use of two secondary windings connected towards each other. Here, the output signal is the vector difference of the voltages arising in the secondary windings when the supply voltage U pit is applied, while the output voltage carries two information: the absolute value of the voltage - about the magnitude of the plunger movement, and the phase - the direction of its movement:

Ū out = Ū 1 - Ū 2 = kX in,

where k is the coefficient of proportionality;

X in - input signal (plunger movement).

The differential principle of the formation of the output signal doubles the sensitivity of the converter, since when the plunger is moved, for example, upward, the voltage in the upper winding (Ū 1) increases due to an increase in the transformation ratio, the voltage in the lower winding (Ū 2) decreases by the same amount ...

Differential transformer converters are widely used in control and regulation systems due to their reliability and simplicity. They are placed in primary and secondary instruments for measuring pressure, flow, levels, etc.

Ferrodynamic converters (PF) of angular displacements are more complex (Fig. 7.4 b and 7.5).

Here, in the air gap of the magnetic circuit (1), a cylindrical core (2) with a winding in the form of a frame is placed. The core is installed using cores and can be rotated through a small angle α in within ± 20 о. An alternating voltage of 12 - 60 V is applied to the excitation winding of the converter (w 1), as a result of which a magnetic flux arises that crosses the area of ​​the frame (5). A current is induced in its winding, the voltage of which (Ū out), other things being equal, is proportional to the angle of rotation of the frame (α in), and the voltage phase changes when the frame is turned to one side or the other from the neutral position (parallel to the magnetic flux).

The static characteristics of the PF converters are shown in Fig. 7.6.

Characteristic 1 has a converter without a bias winding (W cm). If the zero value of the output signal needs to be obtained not on average, but in one of the extreme positions of the frame, the bias winding should be connected in series with the frame.

In this case, the output signal is the sum of the voltages taken from the frame and the bias winding, which corresponds to the characteristic 2 or 2 ", if you change the connection of the bias winding to antiphase.

An important property of a ferrodynamic converter is the ability to change the slope of the characteristic. This is achieved by changing the size of the air gap (δ) between the stationary (3) and movable (4) plungers of the magnetic circuit, screwing in or unscrewing the latter.

The considered properties of PF converters are used in the construction of relatively complex control systems with the implementation of the simplest computational operations.

General industrial sensors of physical quantities.

The efficiency of enrichment processes largely depends on technological modes, which, in turn, are determined by the values ​​of the parameters that affect these processes. The variety of enrichment processes determines a large number of technological parameters that require their control. To control some physical quantities, it is enough to have a standard sensor with a secondary device (for example, a thermocouple - an automatic potentiometer), for others additional devices and converters are required (density meters, flow meters, ash meters, etc.).

Among the large number of industrial sensors, one can single out sensors that are widely used in various industries as independent sources of information and as components of more complex sensors.

In this subsection, we will consider the most simple common industrial sensors of physical quantities.

Temperature sensors. Monitoring the thermal modes of operation of boilers, drying plants, some friction units of machines allows you to obtain important information necessary to control the operation of these objects.

Gauge thermometers... This device includes a sensing element (thermal balloon) and an indicating device connected by a capillary tube and filled with a working substance. The principle of operation is based on a change in the pressure of the working substance in a closed thermometer system depending on the temperature.

Depending on the state of aggregation of the working substance, liquid (mercury, xylene, alcohols), gas (nitrogen, helium) and steam (saturated vapor of a low-boiling liquid) manometric thermometers are distinguished.

The pressure of the working substance is fixed by a manometric element - a tubular spring, which unwinds when the pressure rises in a closed system.

Depending on the type of working substance of the thermometer, the temperature measurement range is from - 50 o to +1300 o C. The devices can be equipped with signal contacts, a recording device.

Thermistors (resistance thermometers). The principle of operation is based on the property of metals or semiconductors ( thermistors) change its electrical resistance with temperature. This dependence for thermistors has the form:

where R 0 – conductor resistance at T 0 = 293 0 K;

α Т - temperature coefficient of resistance

Sensitive metal elements are made in the form of wire coils or spirals, mainly of two metals - copper (for low temperatures - up to 180 ° C) and platinum (from -250 ° to 1300 ° C), placed in a metal protective casing.

To register the controlled temperature, the thermistor, as a primary sensor, is connected to an automatic AC bridge (secondary device), this issue will be discussed below.

Dynamically, thermistors can be represented by a first-order aperiodic link with a transfer function W (p) = k / (Tp + 1), if the time constant of the sensor ( T) is much less than the time constant of the object of regulation (control), it is permissible to take this element as a proportional link.

Thermocouples. To measure temperatures in large ranges and over 1000 ° C, thermoelectric thermometers (thermocouples) are usually used.

The principle of operation of thermocouples is based on the effect of DC EMF on the free (cold) ends of two dissimilar soldered conductors (hot junction), provided that the temperature of the cold ends differs from the junction temperature. The magnitude of the EMF is proportional to the difference between these temperatures, and the magnitude and range of measured temperatures depends on the material of the electrodes. The electrodes with porcelain beads strung on them are placed in protective fittings.

The thermocouples are connected to the recording device with special thermocouple wires. A millivoltmeter with a certain graduation or an automatic DC bridge (potentiometer) can be used as a recording device.

When calculating control systems, thermocouples can be represented, like thermistors, as a first-order aperiodic link or proportional.

The industry produces various types of thermocouples (Table 7.1).

Table 7.1 Characteristics of thermocouples

Pressure Sensors. Pressure (vacuum) and differential pressure sensors received the widest application in the mining and processing industry, both general industrial sensors and as components of more complex control systems for such parameters as slurry density, media flow rate, liquid media level, suspension viscosity, etc.

Gauge pressure measuring instruments are called manometers or pressure gauges, for measuring vacuum pressure (below atmospheric pressure, vacuum) - with vacuum gauges or traction gauges, for simultaneous measurement of excess and vacuum pressure - with manovacuum gauges or traction pressure gauges.

The most widespread are spring-type (deformation) sensors with elastic sensitive elements in the form of a manometric spring (Fig. 7.7 a), a flexible membrane (Fig. 7.7 b) and a flexible bellows.

.

To transmit readings to a recording device, a displacement transducer can be built into the manometers. The figure shows induction-transformer converters (2), the plungers of which are connected to the sensitive elements (1 and 2).

Instruments for measuring the difference between two pressures (differential) are called differential pressure gauges or differential pressure gauges (Fig. 7.8). Here, the pressure acts on the sensing element from both sides, these devices have two inlet connections for supplying higher (+ P) and lower (-P) pressures.

Differential pressure gauges can be divided into two main groups: liquid and spring. By the type of sensing element, the most common among spring ones are membrane (Fig. 7.8a), bellows (Fig. 7.8 b), among liquid ones - bell ones (Fig. 7.8 c).

The membrane block (Fig. 7.8 a) is usually filled with distilled water.

Bell differential pressure gauges, in which the sensitive element is a bell partially submerged upside down in transformer oil, are the most sensitive. They are used to measure small pressure drops in the range of 0 - 400 Pa, for example, to control vacuum in furnaces of drying and boiler plants

The considered differential pressure gauges are scaleless; the controlled parameter is recorded by secondary devices, which receive an electrical signal from the corresponding displacement transducers.

Mechanical force sensors. These sensors include sensors containing an elastic element and a displacement transducer, strain gauge, piezoelectric and a number of others (Fig. 7.9).

The principle of operation of these sensors is clear from the figure. Note that a sensor with an elastic element can work with a secondary device - an AC compensator, a strain gauge sensor - with an AC bridge, piezometric - with a DC bridge. This issue will be discussed in more detail in subsequent sections.

A strain gauge sensor is a substrate on which several turns of a thin wire (special alloy) or metal foil are glued as shown in Fig. 7.9b. The sensor is glued to the sensitive element that perceives the load F, with the orientation of the long axis of the sensor along the line of action of the controlled force. This element can be any structure under the influence of the force F and operating within the elastic deformation. The strain gauge also undergoes the same deformation, while the sensor conductor is lengthened or shortened along the long axis of its installation. The latter leads to a change in its ohmic resistance according to the formula R = ρl / S known from electrical engineering.

We add here that the considered sensors can be used to control the performance of belt conveyors (Figure 7.10 a), measure the mass of vehicles (cars, railway cars, Figure 7.10 b), the mass of material in bunkers, etc.

Assessment of the conveyor performance is based on weighing a specific section of the belt loaded with material at a constant speed of its movement. The vertical movement of the weighing platform (2), mounted on elastic ties, caused by the mass of the material on the belt, is transmitted to the plunger of the induction-transformer converter (ITP), which generates information to the secondary device (U out).

For weighing railway cars, loaded vehicles, the weighing platform (4) is based on strain gauge blocks (5), which are metal supports with glued strain gauges, which experience elastic deformation depending on the weight of the weighing object.

HEAT AND GAS SUPPLY

AND VENTILATION

Novosibirsk 2008

FEDERAL AGENCY FOR EDUCATION OF THE RUSSIAN FEDERATION

NOVOSIBIRSK STATE

ARCHITECTURAL CONSTRUCTION UNIVERSITY (SIBSTRIN)

ON. Popov

SYSTEM AUTOMATION

HEAT AND GAS SUPPLY

AND VENTILATION

Tutorial

Novosibirsk 2008

ON. Popov

Automation of heat and gas supply and ventilation systems

Tutorial. - Novosibirsk: NGASU (Sibstrin), 2008.

The tutorial discusses the principles of developing automation schemes and existing engineering solutions for the automation of specific heat and gas supply and heat consumption systems, boiler installations, ventilation systems and microclimate conditioning systems.

The manual is intended for students studying in the specialty 270109 of the direction "Construction".

Reviewers:

- IN AND. Kostin, Doctor of Technical Sciences, Professor of the Department

heat and gas supply and ventilation

NGASU (Sibstrin)

- D.V. Zedgenizov, Ph.D., senior researcher laboratories

mine aerodynamics IGD SB RAS

© Popov N.A. 2008 r.

MZH VSh-1986 304 p.
The physical foundations of control of production processes, the theoretical foundations of control and regulation, technology and automation equipment, automation schemes for various Tgv systems, technical and economic data and prospects for automation are considered.
Table of contents of the book Automation and automation of heat and gas supply systems and ventilation.
Foreword.
Introduction.
Basics of automation of production processes.
General information.
The importance of automatic control of production processes.
Conditions, aspects and stages of automation.
Features of automation of Tgv systems.
Basic concepts and definitions.
Characteristics of technological processes.
Basic definitions.
Classification of automation subsystems.
Foundations of the theory of control and regulation.
Physical foundations of management and structure of systems.
The concept of managing simple processes (objects).
The essence of the management process.
Feedback concept.
Automatic regulator and structure of the automatic regulation system.
Two ways to control.
Basic principles of management.
Control object and its properties.
The storage capacity of the object.
Self-regulation. The influence of internal feedback.
Lag.
The static characteristics of the object.
Dynamic mode of the object.
Mathematical models of the simplest objects.
Manageability of objects.
Typical research methods Asr and Asu.
The concept of a link in an automatic system.
Basic typical dynamic links.
Operational method in automation.
Symbolic notation of the equations of dynamics.
Structural diagrams. Connection of links.
Transfer functions of typical objects.
Automation equipment and means.
Measurement and control of parameters of technological processes.
Classification of the measured values.
Principles and methods of measurement (control).
Accuracy and measurement errors.
Classification of measuring equipment and sensors.
Sensor characteristics.
State system of industrial instruments and automation equipment.
Means for measuring basic parameters in Tgv systems.
Temperature sensors.
Gas (air) humidity sensors.
Pressure (vacuum) sensors.
Flow sensors.
Measurement of the amount of heat.
Sensors for the level of separation of two media.
Determination of the chemical composition of substances.
Other measurements.
Basic circuits for switching on electrical sensors of non-electrical quantities.
Summing devices.
Signal transmission methods.
Amplifier-converting devices.
Hydraulic boosters.
Pneumatic amplifiers.
Electric amplifiers. Relay.
Electronic amplifiers.
Multi-stage amplification.
Executive devices.
Hydraulic and pneumatic actuators.
Electric actuators.
Driving devices.
Classification of regulators by the nature of the reference action.
The main types of driving devices.
Asr and microcomputer.
Regulatory authorities.
Characteristics of the distribution bodies.
The main types of distribution bodies.
Regulating devices.
Static calculations of regulator elements.
Automatic regulators.
Classification of automatic regulators.
Basic properties of regulators.
Regulators of continuous and intermittent action.
Automatic control systems.
Regulation statics.
Dynamics of regulation.
Transient processes in Asr.
Stability of regulation.
Stability criteria.
Quality of regulation.
Basic laws (algorithms) of regulation.
Related regulation.
Comparative characteristics and choice of the regulator.
Control parameters.
Reliability of Asr.
Automation in heat and gas supply and ventilation systems.
Design of automation schemes, installation and operation of automation devices.
Basics of designing automation schemes.
Installation, adjustment and operation of automation equipment.
Automatic remote control of electric motors.
The principles of relay-contactor control.
Control of an asynchronous electric motor with a squirrel-cage rotor.
Control of an electric motor with a wound rotor.
Reversing and control of standby electric motors.
Remote control circuit equipment.
Heat supply systems automation.
Basic principles of automation.
Automation of district heating stations.
Automation of pumping units.
Automation of replenishment of heating networks.
Automation of condensate and drainage devices.
Automatic protection of the heating network against pressure increase.
Automation of group heating points.
Automation of heat consumption systems.
Automation of hot water supply systems.
Principles of thermal management of buildings.
Automation of heat supply in local heating points.
Individual regulation of the thermal regime of the heated premises.
Pressure regulation in heating systems.
Automation of low power boiler houses.
Basic principles of boiler automation.
Steam generator automation.
Boiler technological protection.
Boiler automation.
Automation of gas-fired boilers.
Automation of fuel combustion devices for micro-boilers.
Automation of water treatment systems.
Automation of fuel preparation devices.
Automation of ventilation systems.
Automation of exhaust ventilation systems.
Automation of aspiration and pneumatic transport systems.
Automation of aeration devices.
Air temperature control methods.
Supply ventilation systems automation.
Automation of air curtains.
Automation of air heating.
Automation of artificial climate installations.
Thermodynamic Basics of Well Automation
Principles and methods of moisture control in Well.
Central Well Automation
Refrigeration automation.
Automation of autonomous air conditioners.
Automation of gas supply systems for gas consumption.
Automatic regulation of gas pressure and flow.
Automation of gas-using installations.
Automatic protection of underground pipelines against electrochemical corrosion.
Automation when working with liquid gases.
Telemechanics and dispatching.
Basic concepts.
Construction of telemechanics schemes.
Telemechanics and dispatching in Tgv systems.
Prospects for the development of automation systems Tgv.
Feasibility study of automation.
New directions of automation of Tgv systems.
application.
Literature.
Subject index.

Download file

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Textbook. for universities / A. A. Kalmakov, Yu. Ya. Kuvshinov, S. S. Romanova, S. A, Shchelkunov; Ed. V.N.Bogoslovsky. - M .: Stroyizdat, 1986 - 479 p: ill.

The theoretical, engineering and methodological foundations of the dynamics of heat and gas supply and microclimate conditioning systems (TGS and SCM) as objects of automation are presented. Given os ...

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Textbook. for universities / A. A. Kalmakov, Yu. Ya-Kuvshinov, S. S. Romanova, S. A. Shchelkunov; Ed. V.N.Bogoslovsky. - M .: Stroyizdat, 1986 .-- 479 p .: ill.

The theoretical, engineering and methodological foundations of the dynamics of heat and gas supply and microclimate conditioning systems (TGS and SCM) as objects of automation are presented. Given the basic ...

• 1.99 MB
• added 02/14/2011

Textbook. manual for universities. - L., Stroyizdat, Leningrad. department, 1976 .-- 216 p.

The tutorial outlines the basic concepts from the theory of automatic control and outlines an engineering approach to the choice of types of regulators, describes the elements of regulators, examines the advantages and disadvantages of the applied circuits and ...

• 1.58 MB
• added 12/02/2008

Khabarovsk, 2005
Album number 1 of typical design solutions
"Automation of heating systems and
hot water supply "

Album No. 2 of typical design solutions

Methodological materials for use
in the educational process and in the design of the diploma.

• 7.79 MB
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Tutorial. K .: Avanpost-Prim, 2005 .-- 560 p.

The textbook is a presentation of the course "Special technology" for the training of adjusters of devices, equipment and systems of automatic control, regulation and management in the field of ventilation and air conditioning.
The book describes the main provisions of the theory of automati ...

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Methodical materials for use. No author.
in the educational process and in the design of the diploma for students of the specialty 290700 "Heat and gas supply and ventilation" of all forms of education.
Khabarovsk 2004 Without author.

Introduction.
Ventilation system with supply air temperature control.
Syst ...

ON. Popov

SYSTEM AUTOMATION

HEAT AND GAS SUPPLY

AND VENTILATION

Novosibirsk 2007

NOVOSIBIRSK STATE

ARCHITECTURAL CONSTRUCTION UNIVERSITY (SIBSTRIN)

ON. Popov
SYSTEM AUTOMATION

HEAT AND GAS SUPPLY

AND VENTILATION
Tutorial

Novosibirsk 2007

ON. Popov

Automation of heat and gas supply and ventilation systems

Tutorial. - Novosibirsk: NGASU (Sibstrin), 2007.
ISBN
The tutorial discusses the principles of developing automation schemes and existing engineering solutions for the automation of specific heat and gas supply and heat consumption systems, boiler installations, ventilation systems and microclimate conditioning systems.

The manual is intended for students studying in the specialty 270109 of the direction "Construction".

Reviewers:

- P.T. Ponamarev, Ph.D. associate professor of the department

electrical engineering and electrotechnology SGUPS

- D.V. Zedgenizov, Ph.D., senior researcher laboratory of mine aerodynamics, IGD SB RAS

© Popov N.A. 2007 year

INTRODUCTION
Modern industrial and public buildings are equipped with sophisticated engineering systems to ensure the microclimate, economic and industrial needs. The reliable and trouble-free operation of these systems cannot be ensured without their automation.

Automation tasks are solved most effectively when they are worked out in the process of developing a technological process.

The creation of effective automation systems predetermines the need for a deep study of the technological process not only by designers, but also by specialists of installation, commissioning and operating organizations.

At present, the state of the art makes it possible to automate almost any technological process. The feasibility of automation is solved by finding the most rational technical solution and determining the economic efficiency. With the rational use of modern technical means of automation, labor productivity is increased, the cost of production is reduced, its quality is increased, working conditions are improved and the culture of production rises.

Automation of TGiV systems includes issues of control and regulation of technological parameters, control of electric drives of units, installations and actuators (IM), as well as issues of protection of systems and equipment in emergency modes.

The tutorial covers the basics of designing automation of technological processes, automation schemes and existing engineering solutions for the automation of TGiV systems using materials from standard projects and individual developments of design organizations. Much attention is paid to the choice of modern technical automation equipment for specific systems.

The manual includes materials for the second part of the course "Automation and control of heat and gas systems" and is intended for students studying in the specialty 270109 "Heat and gas supply and ventilation."

1. DESIGN BASICS

AUTOMATED SYSTEMS

HEAT AND GAS SUPPLY AND VENTILATION

1. 
   Design stages and project composition

In accordance with SNIP 1.02.01-85, the design of automation systems for technological processes is carried out in two stages: a project and working documentation, or in one stage: a working project.

The following basic documentation is being developed in the project: I) block diagram of management and control (for complex control systems); 2) functional diagrams of automation of technological processes; 3) plans for the location of boards, consoles, computer equipment, etc .; 4) application lists of instruments and automation equipment; 5) technical requirements for the development of non-standardized equipment; 6) explanatory note; 7) assignment to the general designer (related organizations or the customer) for developments related to the automation of the facility.

At the stage of working documentation, the following are developed: 1) a block diagram of management and control; 2) functional diagrams of automation of technological processes; 3) basic electrical, hydraulic and pneumatic circuits of control, automatic regulation, control, signaling and power supply; I) general types of boards and consoles; 5) wiring diagrams of boards and consoles; 6) diagrams of external electrical and pipe wiring; 7) explanatory note; 8) custom specifications of instruments and automation equipment, computer technology, electrical equipment, boards, consoles, etc.

In a two-stage design, structural and functional diagrams at the stage of working documentation are developed taking into account changes in the technological part or automation decisions taken during the approval of the project. In the absence of such changes, the mentioned drawings are included in the working documentation without revision.

In the working documentation, it is advisable to give calculations of regulating throttle bodies, as well as calculations for choosing regulators and determining the approximate values ​​of their settings for various technological modes of equipment operation.

The structure of the working project for one-stage design includes: a) technical documentation developed as part of the working documentation for two-stage design; b) local estimate for equipment and installation; c) assignment to the general designer (related organizations or the customer) for work related to the automation of the facility.
1.2. Initial data for design
The initial data for the design are contained in the terms of reference for the development of an automatic process control system. The terms of reference are drawn up by the customer with the participation of a specialized organization entrusted with the development of the project.

The assignment for the design of an automation system contains the technical requirements imposed on it by the customer. In addition, a set of materials required for design is attached to it.

The main elements of the assignment are the list of objects of automation of technological units and installations, as well as the functions performed by the control and regulation system, which provides automation of the control of these objects. The task contains a number of data defining the general requirements and characteristics of the system, as well as describing control objects: 1) the basis for design; 2) operating conditions of the system; 3) a description of the technological process.

The basis for the design contains links to planning documents that determine the procedure for designing an automated process, the planned design timeframe, the stages of design, the permissible level of costs for creating a control system, a feasibility study for the feasibility of designing automation and assessing the readiness of an object for automation.

The description of the operating conditions of the designed system contains the conditions of the technological process (for example, the class of explosion and fire hazard of premises, the presence of an aggressive, humid, damp, dusty environment, etc.), requirements for the degree of centralization of control and management, for the choice of control modes, to the unification of automation equipment, conditions for the repair and maintenance of the fleet of devices at the enterprise.

The description of the technological process includes: a) technological schemes of the process; b) drawings of production facilities with the placement of technological equipment; c) drawings of technological equipment with an indication of design units for the installation of control sensors; d) power supply schemes; e) air supply schemes; f) data for calculating control and regulation systems; g) data for calculating the technical and economic efficiency of automation systems.

1.3. Purpose and content of the functional diagram
Functional diagrams (automation diagrams) are the main technical document that defines the functional block structure of individual nodes for automatic monitoring, control and regulation of the technological process and equipping the control object with instruments and automation equipment.

Functional automation diagrams serve as the source material for the development of all other documents of the automation project and establish:

a) the optimal amount of automation of the technological process; b) technological parameters subject to automatic control, regulation, signaling and blocking; c) basic technical means of automation; d) placement of automation equipment - local devices, selective devices, equipment on local and central boards and consoles, control rooms, etc .; e) the relationship between automation tools.

On functional diagrams of automation, communications and liquid and gas pipelines are depicted with symbols in accordance with GOST 2.784-70, and pipeline parts, fittings, heating and sanitary devices and equipment - in accordance with GOST 2.785-70.

Devices, automation equipment, electrical devices and elements of computer technology on functional diagrams are shown in accordance with GOST 21.404-85. In the standard, primary and secondary converters, regulators, electrical equipment are shown with circles with a diameter of 10 mm, actuators - with circles with a diameter of 5 mm. The circle is divided by a horizontal line when depicting devices installed on boards, consoles. In the upper part of it, the measured or adjustable value and the functional characteristics of the device (indication, registration, regulation, etc.) are written with a conventional code, in the lower part - the position number according to the diagram.

The most commonly used designations of measured quantities in THG systems: D- density; E- any electrical quantity; F- consumption; H- manual action; TO- time, program; L- level; M- humidity; R- pressure (vacuum); Q- quality, composition, concentration of the environment; S- speed, frequency; T- temperature; W- weight.

Additional letters specifying the designation of the measured quantities: D- difference, drop; F- ratio; J- automatic switching, running around; Q- integration, summation over time.

Functions performed by the device: a) display of information: A-alarm; I- indication; R- registration; b) formation of a profitable signal: WITH- regulation; S- enable, disable, switch, alarm ( H and L- respectively, the upper and lower limits of the parameters).

Additional letter designations reflecting the functional characteristics of the devices: E- sensitive element (primary transformation); T- remote transmission (intermediate conversion); TO- control station. Signal type: E- electric; R- pneumatic; G- hydraulic.

The symbol of the device should reflect those signs that are used in the scheme. For example, PD1- a device for measuring the differential pressure, showing a differential pressure gauge, PIS- a device for measuring pressure (vacuum), showing with a contact device (electrocontact pressure gauge, vacuum gauge), LCS-electric contact level regulator, TS- thermostat, THOSE- temperature sensor, FQ1- a device for measuring the flow rate (diaphragm, nozzle, etc.)

An example of a functional diagram (see Fig.1.1),
Rice. 1. 1. An example of a functional diagram

automation of the reduction and cooling plant

where the technological equipment is shown in the upper part of the drawing, and below in the rectangles are devices installed in place and on the operator's (automation) panel. On the functional diagram, all devices and automation equipment are designated by letters and numbers.

The contours of technological equipment on functional diagrams are recommended to be performed with lines 0.6-1.5 mm thick; pipeline communications 0.6-1.5 mm; instruments and automation equipment 0.5-0.6 mm; communication lines 0.2-0.3 mm.

Automation of heat and gas supply and ventilation systems

Section I. BASES OF AUTOMATION OF PRODUCTION PROCESSES

Chapter 1. General information

1. The importance of automatic control of production processes
2. Conditions, aspects and stages of automation
3. Features of TGV systems automation

Chapter 2. Basic ideas and definitions

1. Characteristics of technological processes
2. Basic definitions
3. Classification of automation subsystems

Section II. FUNDAMENTALS OF CONTROL AND REGULATION THEORY

Chapter 3. Physical foundations of management and structure of systems.

1. The concept of managing simple processes (objects)
2. The essence of the management process
3. Feedback concept
4. Automatic regulator and structure of automatic regulation system
5. Two ways to control

1. basic management principles

Chapter 4. Control object and its properties

1. The storage capacity of the object
2. Self-regulation. Impact of internal feedback
3. Lag
4. Object static characteristics
5. Dynamic Object Mode
6. Mathematical models of the simplest objects
7. Object manageability

Chapter 5. Typical research methods for ACP and ACS

1. The concept of a link in an automatic system
2. Basic typical dynamic links
3. Operational method in automation
4. Symbolic notation of equations of dynamics
5. Structural diagrams. Connecting links
6. Transfer functions of typical objects

Section III. TECHNOLOGY AND AUTOMATION MEANS

Chapter 6. Measurement and control of parameters of technological processes

1. Measured value classification
2. Principles and methods of measurement (control)
3. Accuracy and measurement errors
4. Classification of measuring equipment and sensors
5. Sensor characteristics
6. State system of industrial instruments and automation equipment

Chapter 7. Means for measuring basic parameters in THV systems

1. Temperature sensors
2. Humidity sensors for gases (air)
3. Pressure sensors (vacuum)
4. Flow sensors
5. Measurement of the amount of heat
6. Sensors for the level of separation of two media
7. Determination of the chemical composition of substances
8. Other measurements
9. Basic circuits for switching on electrical sensors of non-electrical quantities
10. Summing devices
11. Signaling Methods

Chapter 8. Amplifier-converting devices

1. Hydraulic boosters
2. Pneumatic amplifiers
3. Electric amplifiers. Relay
4. Electronic amplifiers
5. Multi-stage amplification

Chapter 9. Actuators

1. Hydraulic and pneumatic actuators
2. Electrical actuators

Chapter 10. Drivers

1. Classification of regulators by the nature of the reference action
2. The main types of drivers
3. ACP and microcomputer

Chapter 11. Regulatory authorities

1. Distribution body characteristics
2. The main types of distribution bodies
3. Regulating devices
4. Static calculations of regulator elements

Chapter 12. Automatic regulators

1. Classification of automatic regulators
2. Basic properties of regulators

Chapter 13. Automatic control systems

1. Regulation statics
2. Divamics of regulation
3. Transient processes in ACP
4. Stability of regulation
5. Stability criteria
6. Regulation quality
7. Basic laws (algorithms) of regulation
8. Related regulation
9. Comparative characteristics and choice of regulator
10. Control parameters
11. Reliability ACP

Section IV. AUTOMATION IN HEAT AND GAS SUPPLY AND VENTILATION SYSTEMS

Chapter 14. Designing automation schemes, installation and operation of automation devices

1. Basics of designing automation schemes
2. Installation, commissioning and operation of automation equipment

Chapter 15. Automatic remote control of electric motors

1. Relay-contactor control principles
2. Squirrel cage induction motor control
3. Wound-rotor motor control
4. Reversing and control of standby motors
5. Remote control circuit equipment

Chapter 16. Automation of heat supply systems

1. Basic principles of automation
2. Automation of district heating stations
3. Automation of pumping units
4. Automation of replenishment of heating networks
5. Automation of condensate and drainage devices
6. Automatic protection of the heating network against pressure increase
7. Automation of group heating points

Chapter 17. Automation of heat consumption systems

1. Automation of hot water supply systems
2. Thermal management principles for buildings
3. Automation of heat supply in local heating points
4. Individual regulation of the thermal regime of heated rooms
5. Pressure regulation in heating systems

Chapter 18. Automation of low-power boiler houses

1. Basic principles of boiler automation
2. Steam generator automation
3. Boiler technological protection
4. Boiler automation
5. Automation of gas fired boilers
6. Automation of fuel combustion devices for micro-boilers
7. Automation of water treatment systems
8. Automation of fuel preparation devices

Chapter 19. Automation of ventilation systems

1. Automation of exhaust ventilation systems
2. Automation of aspiration and pneumatic conveying systems
3. Automation of aeration devices
4. Air temperature control methods
5. Supply ventilation systems automation
6. Automation of air curtains
7. Air heating automation

Chapter 20. Automation of artificial climate installations

1. Thermodynamic foundations of SCR automation
2. Principles and methods of humidity control in SCR
3. Automation of central storage facilities
4. Refrigeration automation
5. Automation of autonomous air conditioners

Chapter 21. Automation of gas supply and gas consumption systems

1. Automatic regulation of gas pressure and flow
2. Automation of gas-using plants
3. Automatic protection of underground pipelines against electrochemical corrosion
4. Liquid Gas Automation

Chapter 22. Telemechanics and dispatching

1. Basic concepts
2. Construction of telemechanics schemes
3. Telemechanics and dispatching in TGV systems

Chapter 23. Prospects for the development of automation of heating systems

1. Technical and economic assessment of automation
2. New directions of automation of heating systems

The widespread introduction of automation and automation in various branches of technology made it necessary to study the discipline "Automation of production processes" by students of practically all engineering and technical specialties of higher education.

The task of studying the discipline includes acquaintance with modern principles and methods of effective management of production processes and installations, as well as automatic means. The fundamentals of the theory of control and regulation, the principle of operation and the device of automation means, the main fundamental solutions of the circuits are presented. used in heat and gas supply and ventilation (TGV) systems to increase labor productivity and save fuel and energy resources.

Automation of the production process is the pinnacle in the technical equipment of this industry. Therefore, along with the obligatory special knowledge on automation objects, serious training is required in fundamental disciplines - special sections of mathematics, physics, theoretical mechanics, electrical engineering, etc. A feature of automation is the transition from traditional stationary modes and calculations to non-stationary, dynamic, inherent in the field of using automation tools.

The book examines modern domestic automatic systems, as well as some of the latest foreign developments.

When automating, a large amount of graphic material is used in the form of various schemes, therefore, the key to successful mastering the course is the obligatory knowledge of the alphabet of automation - standard symbols. When considering automation schemes, the author limited himself only to fundamental solutions, giving the reader the opportunity to expand his knowledge, using reference and normative literature.

Based on materials from http://www.tgv.khstu.ru