A hazardous area is a space in which exposure to a hazardous or harmful agent is possible. production factor. The danger is localized in the space around moving and rotating elements: cutting tools, parts, faceplates, gears, belt and chain drives, work tables, machines, conveyors, etc., especially when clothes and hair of the worker can be caught. The danger zone may be caused by electrical hazard, exposure to thermal, electromagnetic, ionizing and laser radiation, noise, vibration and other industrial hazards; the possibility of injury by flying parts of the material of the workpiece and tool during processing or from poor fastening of the part, tool. The dimensions of the dangerous zone can be constant (the zone between the pulley and the belt) and variable (the cutting zone). To ensure safety, it is necessary to provide for the use of devices that exclude or reduce the possibility of human contact with the danger zone.

Means of protection of workers according to the nature of their application are divided into two categories: collective and individual. Collective protection means are divided into devices: protective, safety, brake, automatic control and signaling, remote control - and safety signs.

Protective device(guards) - a class of protective equipment that prevents a person from entering the danger zone. Protective devices are used to isolate drive systems of machines and units, zones. Depending on the purpose and frequency of use, fences can be stationary, opening, folding or removable, solid or made of individual sections. For the convenience of servicing the protected parts of machines and mechanisms, doors or covers must be provided in stationary or large-sized fences.

Protective devices must have the necessary rigidity, and fastening must exclude cases of their self-opening. Constructive solutions for protective devices are very diverse. They depend on the type of equipment, the location of a person in the working area, the specifics of hazardous and harmful factors accompanying the technological process. Protective devices are divided into:

• by design - on casings, doors, shields, visors, slats, barriers and screens;
• manufacturing method - into solid, non-solid (perforated, mesh, lattice) and combined;
• installation method - stationary and mobile.

It is possible to use a movable (removable) fence. It

is a device interlocked with the working bodies of a mechanism or machine, as a result of which access to working area at the onset of a dangerous moment.

Portable fences are temporary. They are used in repair and adjustment work to protect against accidental contact with live parts, as well as from mechanical injury and burns. In addition, they are used at permanent workplaces of welders to protect others from the effects of an electric arc and ultraviolet radiation (welding posts). They are most often performed in the form of shields 1.7 m high.

The design and material of the enclosing devices are determined by the features of the equipment and the technological process as a whole. Fences are made in the form of welded and cast casings, gratings, meshes on a rigid frame, as well as in the form of rigid solid shields (shields, screens). Metals, plastics, and wood are used as fencing materials.

Protective devices are used to protect elements of building structures that can cause injuries to workers: low beams, ledges and drops in the floor plane; inconspicuous steps, ramps, places where there is a danger of falling (edges of loading platforms, cargo pallets, unenclosed areas, hatches, openings, etc.), narrowings of driveways, inconspicuous struts, knots, columns, racks and supports in areas of heavy traffic intra-factory transport, etc.; edges of protective devices that do not completely cover the moving elements of production equipment (guards for grinding wheels, milling cutters, gear wheels, drive belts, chains, etc.), enclosing structures of platforms for work carried out at height, as well as process fittings permanently suspended from the ceiling or walls, protruding into the working space.

Safety device designed to eliminate a hazardous production factor at the source of its occurrence.

Safety devices according to the nature of the action are divided into blocking and restrictive.

Locking devices according to the principle of operation, they are divided into mechanical, electronic, electrical, electromagnetic, pneumatic, hydraulic, optical, magnetic and combined.

restrictive device- a device that is triggered in case of violation of the parameters of the technological process or the mode of operation of production equipment. Restrictive devices according to their design are divided into couplings, pins, valves, keys, membranes, springs, bellows and washers.

Brake device designed to slow down or stop production equipment in the event of a hazardous production factor.

Mechanisms and rotating parts that cannot be protected by the nature of their work are equipped with electromagnetic, mechanical, manual, pedal or other braking devices, as well as systems that switch the engine to reverse. Some of the designs of braking devices are combined.

Brake devices are divided into:

• by design - into shoe, disk, conical and wedge;
• actuation method - manual, automatic and semi-automatic;
• principle of action - mechanical, electromagnetic, pneumatic, hydraulic and combined;
• purpose - for working, reserve, parking and emergency braking.

Automatic control and signaling device is designed to control the transmission and reproduction of information (color, sound, light, etc.) in order to attract the attention of workers and make decisions when a hazardous production factor appears or may occur.

Automatic control and alarm devices are divided into:

• by appointment - for information, warning, emergency and response;
• actuation method - for automatic and semi-automatic;
• the nature of the signal - into sound, light, color, sign and combined;
• the nature of the signal - to constant and pulsating. Remote control device designed to control a process or production equipment outside the hazardous area.

Remote control devices are divided into:

• by design - for stationary and mobile;
• operating principle - mechanical, electrical, pneumatic, hydraulic and combined.

Control questions

• 1. What are the main stages of construction preparation?
• 2. What colors are used as signal colors? What do they mean?
• 3. What does the equipping of workplaces include?
• 4. What are the requirements for the placement of construction machines and tools?
• 5. What are lightning rods for? How are they arranged?
• 6. What devices are used as means of collective protection?

determining the required number for ATP

It is advisable to start the selection and determination of the required number of equipment from the basic one (lifts, overpasses, etc.), then complete it with equipment for equipping posts, and compile sets of samples of equipment for personal use.

There are currently two selection methods:

1. Choice technological equipment using the "Table". The “Technological equipment table” establishes typical lists and the need for equipment according to average indicators (single types of vehicles, their operating conditions, typical maintenance and repair technologies, labor intensity standards).

2. NIIAT methodology.

Determining the need for ATP in equipment consists in selecting and compiling a list necessary equipment and establishing the standard (required) quantity of each sample. When determining the need for a number of basic samples by calculation, data are used on the distribution of labor inputs of TO and TR (as a percentage by type of work). When determining the need for inexpensive and simple samples, it is sufficient to use 1–2 ATP factors.

The methodology provides for several ways to determine the need for ATP in equipment:

1. Technological calculation according to the total annual labor intensity of maintenance and repair work performed using a sample, the number of posts and jobs, zones and sections.

2. Expert-technical method. According to the assessment of the technological need for a sample for an operation or work, the implementation of which is impossible without it, it is dangerous to use, or the quality of the results or labor productivity is significantly reduced.

3. Combined method, combining technological calculation and expert-technical method.

When choosing and compiling a list of equipment required for this ATP, the data of the current “Table” are used, the standards for the number of workers employed in maintenance and repair of rolling stock, “Regulations on maintenance and repair of rolling stock road transport”, technological documentation on TO and TR for this ATP, catalogs - reference books on technological equipment of domestic and foreign manufacturers.

The expert-technical method is used when the number of equipment cannot be determined by calculation due to low daily labor intensity or load, or use for non-systematic operations.

The determination of the staff number of equipment for the ATP in a combined way is carried out mainly for equipment, the staff number of which is determined by the technological calculation, but the results are adjusted taking into account the technological, technical and other requirements of the ATP or the sample.

Lecture No. 2 The main structural elements and components of thermal equipment.

Questions:

1. Working chambers.

2. Heating elements.

3. Thermal insulation.

4. Conveying and mixing devices.

6. Means of safety precautions and control and regulating devices.

Working chambers . The main element of the thermal apparatus intended for the thermal processing of food is the working chamber. It represents the space in which the food product is located at the time of thermal exposure.

Closed working chambers include: cooking vessels for digesters and autoclaves, steam chambers, chambers for IR and microwave processing, etc.

Open working chambers communicate with the environment. They may have the shape of a parallelepiped, cube, cylinder or other, in which one of the surfaces that form the volume is missing.

Closed working chambers compare favorably with open chambers in many technical and economic parameters: they are characterized by lower heat losses and, as a result, lower specific energy consumption; in these chambers, technological parameters are more accurately maintained and, consequently, a higher quality of culinary products is achieved.

Despite the disadvantages, open-type cameras are also widespread in enterprises. Catering. This is due to their ease of manufacture and the ability to implement in some of them many technological processes which makes them indispensable auxiliary devices.

The volume of the working chamber is determined, most often based on the volume of products in it, taking into account the safety factor:

font-size:14.0pt;line-height:150%">where V KAM is the volume of the working chamber, m3; V PROD - volume of products, m3; φ - safety factor.

The volume of the food product is determined by the required performance, taking into account the duration of the heat treatment:

font-size:14.0pt;line-height: 150%">where D - productivity of the device, kg/s; τ - duration of heat treatment, s; ρpr - product density, kg/m3,

Heating elements. Products placed in the working chambers are heated by contact with one or another heating medium, which, in turn, is heated by heating elements.

The heating elements are placed in the working chambers, taking into account the requirements of the cooking technology, provided that the loss of raw materials and energy is minimal, as well as the overall cost of production is reduced.

Thermal insulation . This is a layer of material that reduces heat loss in environment. The temperature of the outer walls of apparatuses covered with thermal insulation does not exceed 60 °C for cooking apparatuses and 70 °С for fryers, which eliminates the possibility of burns.

Basic requirements for heat-insulating materials: low coefficient of thermal conductivity, heat resistance and moisture resistance.

In some cases, when the temperature of the working chamber is low, the role of thermal insulation can be played by an air gap between the chamber and the housing. In this case, the thickness of the air gap layer should not exceed 5 ... 10 mm.

Very effective and economical is the combined thermal insulation, consisting of an external air gap and a layer thermal insulation material adjacent to the working chamber or the surface of the heating element placed on its walls.

The calculation of thermal insulation most often comes down to determining the thickness of its layer.

a - heat transfer coefficient from the outer surface of thermal insulation to air, W / (m2 K); t out - temperature of the outer surface of the heat-insulating layer, equal to the temperature of the outer wall of the thermal apparatus, "C; t env - ambient air temperature, °С; t ext - maximum temperature of the inner layer of thermal insulation, °C; λiz is the coefficient of thermal conductivity of the thermal insulation material, W/(m K).

Heat transfer coefficient:

α \u003d 9.7 + 0.07 (t out - t ok p).

Conveying and mixing devices . Conveying devices are used in continuous devices to move the food product inside the working chamber.

Rice. 1. Schematic diagrams of transporting devices:

a - tape; b - chain; in - screw; 1 - driving drum; 2 - driven drum; 3 - working chamber; 4, 5 - intermediate rollers; 6 - idle branch of the conveyor; 7 - working branch of the conveyor; 8 - mesh containers; 5 - shaft; 10 - auger blade (/ p - the length of the working sections of the conveyor)

The main working element of belt technological conveying devices (Fig. a) is a belt made, as a rule, from separate plates.

The belt speed does not exceed 0.1...0.3 m/s.

The performance of the belt conveyor is determined by the formulas:

when moving piece goods

G \u003d 3600 nυ / b,

where G - performance, pcs/h; n - the number of processed products, located simultaneously along the width of the tape, pcs.; υ - belt speed, m/s; b - the distance between the processed products along the length of the tape, m;

when moving bulk materials in a continuous layer, productivity (kg / s)

G = ρLhυ

where p is the bulk mass of the processed food product, kg/m3; L - width - product layer on the tape, m; h - product layer height, m.

In catering establishments, chain conveyors are most often used in steam chambers designed for cooking or defrosting. food products.

As the main element of chain conveyors, a chain is used, made up of individual steel links, flexibly connected to each other. Perforated containers are usually suspended from this chain, designed to contain the food product.

The productivity of the chain conveyor (kg/h) can be determined by the formula

G \u003d 3600 V cap ρφυ / b,

V capacity - capacity for the product, m3; φ - coefficient taking into account the degree of filling of the tank (φ = 0.7 + 0.9); b - distance between containers.

Screw conveying devices (Fig. C) are sometimes called screw. They are used in cylindrical working chambers.

The performance of the screw conveyor is approximately determined by the formula

where G - productivity, kg/s; D - outer diameter of the screw, m; d - shaft diameter, m; S - screw pitch of the screw blade, m; S1 - blade thickness, m; n - screw speed, s-1; p is the density of the product, kg/m3; φ" - coefficient taking into account the uneven loading of raw materials (φ" = 0.15 ... 0.2).

Mixing devices . In the working chambers of apparatus intended for heat treatment of viscous food products with a low coefficient of thermal conductivity, mixing devices (mixers) are placed to intensify the heating process.

Rice. 2. Schematic diagrams of agitators:

a) horizontal; b) horizontal with an inclination (φ - the angle of inclination of the blade); c) vertical; d) planetary; e) anchor; e) screw; g) twin-screw; h) ellipsoid

In devices of periodic action, when mixing homogeneous liquids, mixers with horizontal blades are used (Fig. a). The radially arranged straight blades create an intensive movement of the liquid in the cavity of their rotation and weak mixing along the height of the liquid column. For greater intensification of mixing, the blades are sometimes made inclined (Fig. b).

Agitators with vertical blades (Fig. C) are used for heating and mixing liquids of different densities. Such agitators provide good mixing of liquids throughout the volume.

Agitators with a planetary mechanism (Fig. d) are used when particularly intensive mixing of the liquid is required throughout the entire volume.

Agitators with anchor blades (Fig. e) are used in evaporators, cooking and melting apparatuses. These agitators are designed for constant mixing of the settling food particles in order to prevent possible burning or overheating of these particles during the technological process.

Agitators with screw (fig. e), twin-screw (fig. g) and elliptical (fig. h) blades provide good mixing of viscous food products throughout the volume.

Bearing elements of thermal devices. Elements that perceive and redistribute the force of gravity, the force impact of the working bodies of machines and mechanisms, as well as damping the vibrations that occur during their operation, are called carriers.

The most common in the construction of thermal apparatus as the supporting elements of the frame and frames placed on the bases.

Foundations are the places where machines and mechanisms are installed. Floors can be used as a base industrial premises or specially prepared concrete foundations.

Beds - supporting elements fixed on the bases, providing the distribution of static and damping of dynamic loads.

Usually, the beds are made of all-metal massive, which makes it possible to lower the center of gravity of the apparatus, to give it the necessary stability.

Frame - a supporting structure on which the working chamber of the apparatus, transmission and transport mechanisms, as well as systems that ensure safety and automatic control of processes are mounted technological processing food.

Frames are made in the form of all-metal welded or collapsible (using fixing threaded connections) designs. Standard metal-roll is usually used as the main elements of the frame - corners, channels, beams.

Safety equipment, control devices and auxiliary structural elements

The most common safety precautions include:

1. Means that exclude exposure electric current on the human body: protective grounding system; protective grounding system; protective shutdown system; system of protection against short circuit currents and current overload;

2. Means that exclude the impact of natural gas on service personnel;

3. Means that exclude the ingress of formed products of thermal decomposition of substances in the working chambers, and means that exclude the ingress of fuel combustion products into working room; special ventilation ducts (ventilation devices); traction devices;

4. Means that exclude mechanical destruction as a result of high pressure or vacuum - safety valves.

5. Control and measuring equipment - thermometers, pressure gauges, pressure vacuum gauges various types, intended for registration of the main technological parameters thermal devices.

Technological equipment

The following equipment is used in the production of beer:

• 1. Brewhouse:
  • · Filtrchan
  • Wort kettle
  • · Computer control panel
  • · Mash and decoction kettles
• 2. Fermentation and camp workshop:
  • Cylindrical-conical tanks
  • Horizontal fermentation tanks
  • · Classic camp tanks
• 3. Filtering:
  • Filtration unit SCHENK (Germany)
  • · Porcelain department
  • Yeast branch
• 4. Beer bottling shop:
  • Bottling line (0.5 glass)
  • Bottling line (3L PET)
• 5.CIP station
• 6. Carbon dioxide collection station

Characteristics of documented methods

In the course of the enterprise's activities, appropriate documented methods are used that determine the method of production, affecting the quality, based on standards, specifications, regulatory documents for the method of production. Regulatory documents include documents that establish rules, principles, characteristics relating to various kinds activities and results.

The requirements established by regulatory documents are based on modern achievements in science and technology, technology and regulated standards, progressive scientific standards of other countries.

The standards include documents in which, for the purpose of voluntary reuse, product characteristics, rules for the implementation and nature of the production process and all stages and stages are established. life cycle products.

Technical documents, which are not normative, are considered as normative if they are referred to in contracts or contracts for the supply of goods.

in the production of beer and soft drinks OJSC "Vyatich" uses the following regulatory documents: GOSTs or state standards(for raw materials, for finished products, for means of production); TU or specifications(for finished products, they are designed at the enterprise itself); SanPiNs or sanitary rules and norms (used to control the quality of raw materials and finished products microbiological and safety parameters). Examples of documents are given in the Appendix.

At present, the calculation of the need for ATP in technological equipment and its selection is carried out according to the current Table of technological equipment and a specialized tool for the ATP of Russia. Report card as a leader normative document for all ATPs in Russia, establishes a typical list and the need for equipment according to an average indicator (single types of vehicles, their operating conditions, typical maintenance and repair technologies, standards for their labor intensity, etc.) for specialized ATPs and does not take into account such important factors as different brands and types of the rolling stock fleet, local production conditions and operating conditions of vehicles at ATP, etc. The underestimation of these factors leads to the erroneousness of the decisions made when determining the needs of the ATP in equipment, to a decrease in the possible prospective level of mechanization of maintenance and repair, the effectiveness of mechanization, irrational use equipment and its distribution between sites, etc.

The methodology developed at NIIAT makes it possible to make a more correct and objective choice and determine the need for equipment for each ATP based on data characterizing local conditions production and operation of rolling stock. The technique can be used for:

Determination of the required lists and the required number of units of technological equipment in the reconstruction of existing and design of new ATP, individual zones, sections;

Evaluation of the correctness of equipping a particular ATP with technological equipment;

Distribution of technological equipment between zones, sections, posts;

Drawing up annual applications for the ATP for the purchase of new technological equipment;

Development of long-term plans for the development of the production base of ATP.

The methodology applies to all types and models of technological equipment and tools used in maintenance and TP of vehicles.

The selection and compilation of a list of the necessary equipment should be made according to the nomenclature, technical characteristics of the samples given in the current Table, recommended in the Methodology, and the definition regular number each sample according to the recommendations given in the Methods sections.

The methodology makes it possible to more fully take into account the local conditions of the work of the ATP, significantly reduce the likelihood of making erroneous decisions when equipping work posts and places with equipment and distributing it between the zones and sections of maintenance and TP, contributes to obtaining a higher technical and economic effect from the implementation of the planned measures for mechanization, increasing quality and reduce the cost of maintenance and repair work.

Determining the need for ATP in equipment consists in selecting and compiling a list of the necessary equipment and establishing the standard (required) quantity of each sample.

Determining the need for equipment is based on the analysis and mutual rational linking of the factors of ATP and SRT of equipment factors.

Data on ATP are determined according to the relevant (technical, reporting and other) documentation or calculations, and for equipment - according to technical specifications of each sample, given in the current Table of equipment catalogs, sample passport or other sources of information. During the reconstruction of the ATP or the construction of new ones, the data are established according to the design documentation.

Depending on the nature of the activities carried out at the ATP, when determining the need for equipment, all or only part of the factors of the ATP are taken into account. Equipment factors and ATP are subjected to a more versatile and in-depth analysis when determining the need for expensive, complex, large-sized equipment samples.

When determining the need for a number of basic equipment samples (car wash lines, etc.) by calculation, it is necessary to use data on the distribution of maintenance and TP labor costs as a percentage by type of work, given in the current Regulation on maintenance and repair of rolling stock of road transport.