Diploma - Goat crane

Contents

Contents

 

Introduction

1 Analysis of existing structures

2 Design calculations

2.1 Calculation of lifting mechanism

2.2 Calculation of trolley movement mechanism

2.3 Calculation of crane movement mechanism

3 Strength calculations

3.1 Calculation of crane running wheels strength

3.2 Calculation of bearings

3.3 Calculation of running wheels

4 Operating part

4.1 Maintenance

4.2 Lubrication of crane mechanisms

4.3 Types of repairs

4.4 Faults of crane equipment

5 Occupational safety

5.1 General Information

5.2 Rules for Crane Driver

6 Industrial ecology

6.1 General Information

6.2 Measures to reduce environmental hazards

7 Economic justification

Conclusion

List of literature used

Introduction

 

Goat cranes of various types are increasingly used in many sectors of the national economy in transshipment, installation and other works.

The structural features of goat cranes are largely determined by their purpose. In addition to a relatively small number of various special purpose cranes, it is necessary to allocate cranes for servicing hydraulic structures, for construction and installation work, for the assembly of ships and gantry cranes for general purpose, which are also otherwise called reloading gantry cranes.

Cranes of the first group are equipped with several lifting mechanisms with a lifting capacity of up to 500 tons and have relatively low operating speeds. They have a particularly massive design and are designed for a long life.

Cranes for construction and installation work are made with a lifting capacity of 1 to 400 tons and are adapted for frequent relocation. They, as a rule, can, depending on local conditions, be assembled in various (up to 15-20) versions with varying span, lifting height of cargo, etc. Cranes of this type are made with a conless or cantilever bridge. The speeds of working movements are low, the mode of operation is light. From the number of shipbuilding in recent years, cranes for sectional assembly of ships have begun to spread, the carrying capacity of which reaches 800 tons with spans of up to 80-140 m and a lifting height of up to 60-80 m.

Recently, special cranes for reloading large-capacity containers weighing up to 40 tons have also become widespread.

The most common are cantilever gantry cranes for general purposes, serving warehouses of piece and bulk cargo, railway container sites, lower warehouses of timber farms, etc. They are also widely used at various technological facilities: landfills for the production of reinforced concrete products, open assembly sites of factories, etc. The load capacity of these cranes is assigned within 3-50 tony are manufactured mainly with two-console bridges.

The increasing proliferation of goat reloading cranes in the domestic economy is a consequence of the fact that, like bridge cranes, they have high productivity and are easy to manage. Gantry cranes do not require the installation of crane racks (which reduces the cost of the transshipment installation by 40-60%) and can move cargo from the span on the bridge console; their installation is much easier with almost the same labor input.

In particular, goat cranes have become the main means of mechanizing transshipment work at rail warehouses and transshipment sites, and their use in the construction materials industry is increasing.

1 Analysis of existing structures

Goat cranes designed for the mechanization of transshipment and warehousing are of great use in industry. General-purpose cranes usually have a carrying capacity of 3.2... 50 t, spans of 10... 40 m, lifting height of 7... 16 m. Goat cranes with a carrying capacity of over 8 t are used to service warehouses of long-sized cargoes, open landfills of reinforced concrete products factories, shipping sites of machine-building plants, etc. When spans up to 35 m, the use of cranes with double-beam bridges and simple two-rail support freight carts of bridge cranes is justified. Placing a suspension between bridges allows you to 10... 15% reduce the height of the crane, although it should be noted that double-beam bridges are complex to manufacture and metal-intensive. In this work, we design a general purpose gantry valve of normal design with two rigidly fixed supports and a flexible suspension of the load-gripping element. Steel structures of cranes of normal design are made of sheets; mechanisms of such cranes consist of separate units connected by toothed couplings; gears are made in the form of separate reduction gears, running wheels are installed on angular axles. Figure 1.1 shows the diagram of the goat crane.

Design calculations

 

2.1 Calculation of lifting mechanism

2.1.1 Selection of kinematic diagram of lifting mechanism drive 

General calculation of load lifting mechanism includes selection of hook with suspension, polyspast, engine, reduction gear, couplings, brake, selection of rope, calculation of drum.

It is necessary to calculate the mechanism for lifting the load of an electric goat crane with a lifting capacity of Q = 20,000 kg for mechanization of transshipment work in open areas of enterprises. Lifting speed of the load has to be № g = 0.16 m/s. Lifting height H = 12 m. Mechanism classification group M3 in accordance with ISO 4301/1 − 86, in accordance with GOST 25835 − 83 - 3M. Kinematic diagram of lifting mechanism drive is shown in Figure 2.1.

 Operational part

4.1 Maintenance

Maintenance of cranes consists of operations regulated in the documentation to maintain their operability and serviceability during the service life. Maintenance of cranes is performed during overhaul periods. The following types of maintenance are recommended depending on the scope, labor intensity and periodicity of the performed works:

daily (EO);

Maintenance No. 1 (TO-1);

Maintenance No. 2 (TO-2);

Maintenance periodicity TO-1 - not more than 1250 hours, and TO-2 - not more than 5000 hours of machine time.

The structure of crane maintenance is as follows: M-TO-1 -TO-1 -TO-1 -TO-2-TO-1 -TO-1 -TO-1-TO-2-TO-1 -TO-1 -TO-1 M, where M is small repair.

Daily maintenance of the crane (not more than 45 minutes) includes:

- serviceability check of safety devices;

cleaning of the cockpit, cleaning from dust and dirt of running trolleys and mechanisms of the cargo trolley;

inspection of ropes and slings;

troubleshooting detected faults.

During TO-1 (duration not more than 4 hours), the operations provided for daily maintenance are performed, and additionally it is necessary to inspect and check:

- mechanical equipment and metal structures (absence of cracks, thickness of elements subject to corrosion);

welds on structural steel bearing elements;

places of attachment of axle boxes of running wheels;

dead-end stops and their attachment states;

value of hook wear in dangerous sections;

- correct installation  and attachment of buffers   and movement limiters; if necessary, tighten the attachment;

tightening of cover and gear box housing attachment; condition of panel attachment for inspection of gear box bearings; if necessary, tighten the attachment;

tighten the condition and tightening of plugs of oil filling and oil discharge holes of reducers, if necessary;

couplings and shafts, check tightening of bolts connecting parts of couplings; if necessary, tighten the bolts;

drum, rope and bearing housings attachment; if necessary, tighten the attachment;

degree of wear of drum cutting ridge, serviceability of rope clamping devices;

- rope units, attachment of their axes and bearings, turning of units on axes, condition of flanges and streams of units;

- rope, clean it from dust; wash and grease;

- attachment of the holder and cross-arm of the hook; if necessary, tighten the attachment; 

- running wheels (pay attention to the wear value in the rolling circle along the flanges    );

- electrical equipment,  grounding circuit, presence , compliance , serviceability of starting equipment , absence of noise, vibration  and excessive heating of electric motor housings during operation, electromagnet control circuit;

- track switches , rotation of their shafts  , action of device of levers self-return to initial position  , action of contact  elements.

During maintenance No. 2, the works stipulated by TO-1 are carried out and additionally:

to believe that there is no violation of the alignment of the shafts of electric motors and reduction gears, as well as the attachment of axle boxes, the condition of bearings of running wheels, drum, blocks, suspensions; Add or replace lubricant, if necessary;

inspect electrical equipment, clean accessible parts of electric motors , braking devices , holes of ventilation casing; check attachment of parts of braking device and engines to places of installation; check motor bearing panels, condition of contacts and starting equipment, insulation resistance (dry if necessary ); check the vibration  and noise level of the motors  ; check the clearance between the shoes and the brake pulley; brake torque value; check the ground condition.

4.2 Lubrication of crane mechanisms

During operation of the crane, friction occurs in bearings and wheels, gear and hinge gears, block units and hinge joints, leading to increase in temperature and wear of friction surfaces near the strut. To reduce friction heating and wear of friction surfaces, we use various lubricants (oil, fat, graphite, etc.). - substances having the ability to firmly cover rubbing parts with protective film. The friction force between the film is much less than the friction force between the dry surfaces of the friction parts, and the film does not break even if the two friction parts act on one another with greater force. Thus, the main purpose of the lubricant is to reduce the friction force in the rotating parts and, as a result, reduce energy consumption, increase the efficiency, reduce wear of the friction parts, as well as prevent metal corrosion. To lubricate the mechanisms of cranes, two types of lubricants are used: liquid and grease plastic. Each operating manual of the valve has a lubrication card, the diagram of which shows the lubrication points and their numbers, and the text contains the names of the mechanisms or parts to be lubricated, the name of the grades and the periodicity of lubrication replacement. during maintenance of cranes it is necessary to strictly follow the instructions contained in lubrication cards. The valve lubrication is performed according to lubrication diagrams, in compliance with the following requirements:

before lubrication, carefully remove dirt from the oils, plugs of the lubricated surfaces, as well as wiping the syringe, lubricating equipment;

oil is poured into reduction gear box through filling funnel with clean mesh pre-laid in it;

after draining the extracted oil to the reduction gear box, fill the diesel fuel and at idle roll the mechanisms for 3-5 minutes, then drain the washing liquid, and fill the fresh oil with the lubrication table, respectively;

lubrication of the units is carried out immediately after stopping the crane (especially in winter), while the rubbing parts are heated, and the lubrication is liquefied, which will accelerate the lubrication process and ensure its supply to all rubbing surfaces;

in cold season oil is heated to 8090% (but not open fire) to accelerate filling;

When the lubricant is supplied to the friction units by the syringe, we ensure that the fresh lubricant reaches the friction surfaces and squeezes out the old lubricant (in places where this requirement cannot be met, a certain amount of lubricant is needed). Then, the lubricant squeezed out of the gap is removed by wiping dry at a given place;

lubrication of rollers, control axes is produced through appropriate lubrication holes or gaps between friction parts, or during partial disassembly;

hydraulic system filling with operating fluid is performed in accordance with the valve operating manual.

4.3 Types of repairs

Ongoing repairs (small, medium goat cranes) are carried out in the workshops and in the areas where they are installed and operated. Taking into account the structural features of the crane, the mode and conditions of its operation, we regulate a specific amount of repair work.

Works performed during maintenance 1:

development and inspection of individual units, which are inaccessible for direct observation, defect of parts requiring replacement or restoration;

checking the condition of the cargo hook, its support and attachment, as well as the condition of the hook suspension;

defect of transmission shafts of reduction gears, splines and key joints;

monitoring of connection strength of half-couplings attachment on the shaft, degree of teeth wear in toothed joints, elastic rings and holes in bushing-flange couplings, as well as replacement of worn-out parts and alignment of couplings;

inspection and revision of running wheels (condition and degree of wear of rolling surfaces, presence of cracks and breakaways on attachment of gear rims;

check of brakes of all crane mechanisms (condition of working surfaces of brake pulleys and friction liners, shoes and belts), restoration or replacement of extremely worn parts, adjustment of brakes;

performance of works stipulated by crane maintenance, as well as inspection of ropes and their attachment, check of operation of all safety devices and devices, addition or replacement of lubricant in friction units.

Works performed during maintenance 2:

replacement of damaged defective transmission shafts, worn-out reduction gears, equipment of centralized lubrication systems and other components of units, mechanisms and metal structures that are not suitable for further operation;

replacement of damaged and extremely worn running wheels;

check and elimination of running-in of one crane support or slippage of running wheels;

replacement of worn-out sections of trolley track;

revision of drums, compensating units, lifting mechanisms with replacement (if necessary) of worn out parts;

performance of works stipulated by Maintenance 1. The procedure for disassembly, defectation, repair, assembly of cranes units and mechanisms shall be specified in the regulatory and technical documentation for repair and in the operating instructions for cranes of manufacturers.

Industrial ecology

6.1 General Information

Environmental protection is a system of measures aimed at maintaining interaction between human activity and habitat, ensuring the conservation and restoration of natural wealth, rational use of natural resources, preventing the direct and indirect impact of the results of society on nature and human health. The commissioning of railway transport facilities is allowed when fulfilling all environmental requirements determined by regulatory and technical documentation and legal acts, when equipping them with means of nature protection, after conducting an environmental assessment of the environmental impact of objects.

When operating railway transport facilities, standards for the consumption of natural resources, maximum permissible impacts on natural complexes, established standards for maximum permissible emissions (MPA), discharges (MPA), and physical radiation (MPA) must be observed by local authorities.

Emergencies in peacetime arising from various factors are classified as follows: situations accompanied by the release into the environment of hazardous substances associated with the occurrence of fires, explosions and their consequences; transport communication situations, including collision and derailment of railway trains, accidents on product pipelines, on main engineering networks, especially electric ones, resulting in disruption of the life of the population in a large area; natural disasters, including earthquakes of 5 points or more (on a 17-point scale), catastrophic floods and floods, tsunamis, massive forest and peat fires, epidemics; situations of a military-political nature in peacetime, including international terrorism and banditry, committed against individual citizens or objects, explosions in public places, on the streets, at airports, train stations, etc.

In this regard, security in practical conditions is carried out in two areas:

prevention of output of systems (objects, processes) to emergency (non-calculated) modes, which is achieved by ensuring reliability, durability, reliability;

prevention of escalation of emergency situation into accident and catastrophe, which is achieved by performing technical diagnostics and providing protective equipment.

From the point of view of assessing the types and sources of pollution of the environment by transport, two approaches can be considered: traditional, covering only the transport processes themselves, and complex, including the full range of possible factors related to transport.

The traditional approach takes into account the inflow of pollutants into the biosphere directly as a result of the functioning of the rolling stock, for example, the exhaust gases of transport engines entering the air, and the discharge of effluents into the reservoirs. This includes occasional accidents of vehicles with dispersion in the biosphere of their cargoes - toxic, aggressive, radioactive and other substances. Such contamination occurs due to technical imperfections of vehicles or personnel errors. The integrated approach differs from the traditional one in that it additionally takes into account the pollution of the biosphere or its changes as a result of transport construction and operation of transport enterprises, which should include repair plants, depots and other permanent structures.

Along with sulfur compounds, vehicles and combustion plants emit significant amounts of nitrogen oxides (forming nitric acid with atmospheric moisture), as well as fluorine, chlorine, hydrochloric acid and others.

These very active substances not only adversely affect the living world, but also intensely destroy metal structures, paint coatings and even concrete and stone structures.

Great damage is caused to buildings, bridges and other transport facilities. Biological contamination of water and land is caused by insufficiently treated effluents from vehicles and permanent structures. Such pollution is found in freshwater basins, which are consumed in some cases for drinking.

Water treatment methods are divided into mechanical, chemical and biological. Mechanical purification consists in the sludge of water in special tanks or land reservoirs, as well as in its passage through filters that deter solid particles in a suspended state and a significant part of undissolved carbon.

However, it should be recognized that these devices can no longer meet modern requirements, and they are replaced by more advanced ones. For example, more efficient settling tanks for clarifying turbid and colored waters are being introduced. For a more complete separation of petroleum products, flotation plants have been created, which equip depots, repair plants, and trellopropytic enterprises.

Chemical purification uses appropriate reagents that remove or neutralize harmful chemical impurities in waste water. 

At large repair plants, depots, closed systems begin to be used, where synthetic detergents after washing rolling stock, various units and parts (before repair, painting, chrome plating and other operations) are not dumped into the sewer, but are regenerated and reused. In such systems, the spent detergent solution is settled, then sludge dropped to the bottom of the tank and oil products floated to the surface are removed from it. Finally, if the solution is heavily contaminated with fine particles, it is subjected to a second purification cycle using coagulants. Such reagents include iron sulphate and magnesium oxide hydrate or mixtures thereof. After they are added to the solution, a precipitate falls on the bottom, which is removed, and the clarified solution with the addition of a fresh portion of detergent goes into operation. Sludge removed from solution is destroyed, and petroleum products are used as fuel.

6.2 Measures to reduce environmental hazards

In order to reduce the harmful impact on the environment, environmental measures must be carried out during design, construction and operation.

Around the enterprise there should be a sanitary protection zone at least 50 m wide. This zone is landscaped and landscaped. Green spaces enrich the air with oxygen, absorb carbon dioxide, noise, clean the air from dust and regulate microclimate.

Production with harmful secretions (painting, blacksmithing, woodworking and other areas) is concentrated, if possible, in branches on the outskirts of the city.

The maximum permissible emission of harmful substances into the atmosphere is determined in accordance with the requirements of GOST 17.2.3.0298. At the same time, it is assumed that the concentration of harmful substances in the surface layer of the atmosphere should not exceed MPC.

In order to maintain the purity of atmospheric air within the limits of standards, the automotive repair plant provides for the preliminary purification of ventilation and process emissions with their subsequent dispersion in the atmosphere.

Air removed from the painting compartment using spray painting is cleaned in hydrofilters before being released into the atmosphere.

Afterburning or catalytic afterburning is used to clean the air removed from the drying chambers. In the first case, the solvent vapors contained in the air are combusted in the burning natural gas jet, in the second case, the contaminated air is heated to 400 C and supplied to the catalyst, where the harmful gaseous impurities are afterburned.

Wet dust collectors, such as bubble bubbles, are used to clean the air from welding aerosol released during welding, where contaminated air in the form of bubbles passes through the liquid layer and is cleaned. Plate electrofilters can also be used, in which dust particles receive an electric charge and settle on the electrode, while the cleaning efficiency is 0.95.

Reducing the emission of harmful substances by boiler plants can be achieved by transferring from flaring liquid fuel to the combustion process with excess air (supercharged). In addition, during the entire heating season it is necessary to clean the chimneys at least once every 2 months. It is also important to repair them in a timely manner.

In cases where treatment facilities cannot or are not available, the concentration of harmful substances in the air of the surface layer can be reduced by rational dispersion of dust and gas emissions in the atmosphere. This is achieved by means of high pipes, exhaust shafts of increased height or increased emission speed (flare release).

The atmosphere in the surface layer is favorably affected by artificial reservoirs which absorb dust, humidify, cool and ionize the air.

Conclusion

To carry out modernization, we needed to capitalize 1760 thousand tenge, while the cost of maintaining and operating the crane per 1 ton of cargo amounted to:

up to modernization 0.0132 thousand tenge;

after modernization of 0.0099 thousand tenge, i.e. decreased  by 0.0033 thousand tenge, which made it possible to obtain savings on actual crane productivity of 2746.22 thousand tenge.

The payback period for additional capital investments is 0.64 years.

Calculation of economic efficiency of crane modernization indicates its feasibility.