Repair of the press roll grinder - course project

Introduction

The shortage of material and energy resources does not make it possible to adequately provide enterprises with new industrial equipment, therefore, in order to maintain the existing fleet of industrial equipment in working condition, it is necessary to develop and improve the repair services of enterprises, that is, services that ensure the restoration of the operability of machines and equipment.

When restoring worn-out parts, the so-called repair blanks are obtained by applying an additional layer of material - a repair allowance - to the worn-out surfaces. The use of such blanks makes it possible to significantly reduce the number of technological operations in the manufacture of an article suitable for installation in industrial equipment.

A well-designed recovery process allows you to obtain parts with properties close to, and in some cases superior to, the properties of a new part.

It is also important that the restoration of worn-out parts is an environmental and resource-saving process. For example, 57 kg of metal and about 1 MJ of energy are used to manufacture a 4.8 liter crankshaft of an internal combustion engine, with a chip loss of about 2.5 kg in the processing step. When restoring the same crankshaft, metal costs will be approximately 2.6 kg, energy costs 9.5 MJ, and waste losses - only 0.12 kg.

However, the standard operating time of the restored industrial equipment (its service life) is approximately half that of the standard operating time of the new equipment, however, when using modern restoration methods and optimal organization of the technological process, the use of the restored industrial equipment is reasonable and economically profitable.

1.1 Name, classification and technical characteristics of machines.

Grinding is a process of sequentially reducing the size of pieces of solid material from the initial size to the desired size. When crushed stone is produced, a finished product is obtained as a result of grinding. In other cases, this process is preparatory for further processing, for example, in the production of cement.

Depending on the initial and final size of the pieces of material, two main types of grinding process are distinguished: crushing and grinding. Depending on the size of the final product, it is distinguished: crushing - large (size of pieces 100350 mm), medium (40100 mm), small (540 Mm); grinding - coarse (particle size 50.1 mm), thin (0.10.05 mm), ultra-thin (less than 0.05 mm).

Theoretical foundations of crushing and grinding of stone materials. The energy required for grinding the material depends on a number of factors: strength, brittleness, homogeneity of the starting material, its humidity, size, shape, mutual arrangement of the pieces, crushing method, type and state of the working surface of the machine, etc. Analytical relationships that establish the relationship between the energy consumption for grinding and the physical and mechanical properties of the ground material and the parameters of the final product are approximate.

To determine the energy necessary for grinding, several hypotheses have been developed: the first speaks of the proportionality of the energy of the newly formed surface (the first hypothesis of grinding is the hypothesis of surfaces); the second is about the proportionality of energy to the volumes or masses of divided bodies (the second hypothesis is volumes); the third, combined, hypothesis speaks of the proportionality of the grinding energy to the resulting surfaces and volumes of crushed bodies.

Classification of methods and machines for grinding materials. Depending on the purpose and the principle of operation of machines designed for grinding materials, the following methods of destruction are used: crushing (Fig. 1.1, a), impact (Fig. 1.1, b), splitting (Fig. 1.1, c), fracture (Fig. 1.1, d), abrasion (Fig. 1.1). At the same time, several methods can be implemented simultaneously, for example, crushing and abrasion, impact and abrasion, etc. The need for various grinding methods, as well as different structures and sizes of grinding machines, is caused by a variety of properties and sizes of the materials being ground, as well as various requirements for the size of the finished product. Machines used for grinding are divided into crushers and mills.

3.2 Maintenance, maintenance and overhaul of equipment.

Typical works performed during maintenance, repair of equipment

The scheduled preventive repair system includes:

- daily maintenance;

- periodic maintenance;

- ongoing repair;

- overhaul;

- equipment modernization;

- unscheduled repair.

Daily maintenance

Daily maintenance of the equipment includes the following works:

- external inspection, lubrication, in accordance with lubrication map, and equipment cleaning;

- troubleshooting of small faults and adjustment of individual devices;

- supervision of compliance with the rules of equipment operation.

Workers-operators and on-duty workers of the repair and maintenance service take part in the daily maintenance of the equipment.

The results of daily maintenance are reflected in reports of locksmiths on duty on daily maintenance and recorded in the equipment maintenance register.

Periodic maintenance

Periodic maintenance of the equipment includes the following list of works:

- permanent cleaning of equipment and premises, where it is installed;

- daily and periodic inspections of equipment;

- monitoring of the state of geometrical dimensions of the assembled shapes;

- daily and periodic lubrication of friction conjugates;

- periodic flushing of tanks and systems for lubrication of friction surfaces of equipment parts;

- periodic replacement of lubricant in equipment crankcase;

- adjustment of movable joints of parts and mechanisms of equipment and moulds;

- lifting of detachable connections attachments;

- check of friction and rolling surfaces condition

- check of serviceability of limitation stops, ceilings;

- checking and tightening of loosened bolts, keys. Replacing Worn Parts Listed

-Verifying the operation and regulation of coupling and brake connections;

- replacement of parts with service life less than the overhaul period;

- continuous check of equipment accuracy;

- inspection and testing of electrical equipment.

Scheduled maintenance is performed during equipment interruptions. Works performed during periodic maintenance are noted in the report of the team of locksmiths on maintenance are recorded in the equipment maintenance register and are taken into account in the equipment logbook

Inspections of equipment subordinate to Gosgortekhnadzor are carried out according to the schedule developed in accordance with the Rules of Gosgortekhnadzor. Inspection of equipment under Gosgortekhnadzor is carried out periodically in accordance with the schedule approved by the chief engineer of the enterprise and agreed with Gosgortekhnadzor.

Maintenance

List of typical works performed during the current repair:

- repeat all periodic maintenance activities

- check the whole machine;

- partially disassemble the equipment or machine, remove all fences and casings. Disassemble in detail the units subject to the greatest wear and tear, which will not ensure their reliable operation until the next repair cycle;

- clean all equipment and moulds, wash parts of disassembled units;

- check clearances between rollers and bushings, replace or repair worn out parts;

- check the operation of couplings and brakes, if necessary replace the ring or linings. Adjust friction clutches and brakes;

- replace worn gears, grind burrs on gear teeth;

- replace worn and broken fasteners: bolts, screws, nuts, pins, cotter pins, etc., grind other fasteners;

- check the operation of the equipment, parts of the start-up and stop mechanisms of the machines, locking, fixing and safety devices, if necessary, eliminate the detected defects;

- replace worn out parts that will not be able to work until the next scheduled repair;

- repair safety and protective devices;

- check the lubrication supply system operation, repair it if necessary;

- check the condition of springs and replace them if necessary;

- replace worn belts;

- assemble repaired equipment units, check their operability;

- identify parts requiring replacement during the next scheduled repair;

- check equipment operation at idling, noise and bearing heating. If faults are detected, they must be eliminated;

- perform works on electrical equipment

Depending on the accepted form of organization of the repair and maintenance service at the enterprise, the current repair is carried out by the production shop operating the equipment, or the repair and mechanical workshop.

Overhaul

Works performed during overhaul:

- all maintenance works are performed

- Complete disassembly of the machine and its units;

- replacement or repair of basic parts;

- replacement or restoration of all worn out parts;

- Stagnation or stacking of rails;

- replacement of gearboxes, electric motors, and other equipment components if necessary;

- check of condition and repair of linings;

- assembly of all machine units, check of correct interaction of units and all machine mechanisms. Idling and load test

- filling and painting of the machine surface, replacement of the plate;

- perform works on electrical equipment

The scope of work for each specific type of equipment or form is determined by the list of defects, which is compiled during the previous scheduled repair and specified during disassembly of units or assemblies and defects of equipment and form parts.

Overhaul of equipment and forms at the plant operating them is carried out by the repair and mechanical workshop or from the branch inter-plant repair specialized enterprise.

Unscheduled repair

This type of repair is carried out in case of failures or accidents of equipment that is in operation. The reasons for unscheduled repairs of the equipment are violations of the maintenance rules and operating modes established by the manufacturer's instructions, defects arising during design, manufacture and repair, damage or hidden defects, as well as natural or accelerated processes of wear of mating parts.

A violation of the production process of a site, workshop or enterprise caused by a failure of the equipment is considered an accident.

Ways to improve equipment maintenance and repair:

- improving the quality of maintenance, strengthening the responsibility of maintenance duty and repair personnel of workshops and operational personnel;

- rational centralization of current and major repairs in order to ensure the optimal ratio of the composition and volume of repair work (both for workers in workshops and for specialized repair enterprises);

- improving the clarity of equipment repair planning, implementation of warranty repairs;

- maximum application of nodal and aggregate repair methods, implementation of strengthening technologies;

- Improved accounting and systematic analysis of the causes of unscheduled equipment outages

The main content of the STOIR system is:

1. Maintenance of equipment during the overhaul period taking into account diagnostics of its technical condition and compliance with all norms and rules

2. Execution of planned preventive repairs of equipment

3. Continuous improvement of equipment design and its modernization to improve reliability, repairability and improve operating conditions

The STOIR

system adopts the following concepts and definitions:

Maintenance - a set of operations or an operation to maintain the operability or serviceability of the product during use as intended, waiting, storage and transportation.

Maintenance (repair) periodicity is the interval of time or operating time between this type of maintenance (repair) and the subsequent same type or other of greater complexity.

Duration of maintenance (repair) - calendar time of one maintenance (repair) of this type.

Labor intensity of maintenance (repair) - labor costs for carrying out one maintenance (repair) of this type.

Scheduled repair - repair, installation on which is carried out in accordance with the requirements of regulatory and technical documentation.

Scheduled repairs include maintenance and major repairs.

Routine repair - repair performed to ensure or restore the operability of the product and consisting in replacement and (or) restoration of individual parts.

Overhaul - repair performed to restore serviceability and complete or close to complete restoration of the product life with replacement or restoration of any parts thereof.

Repair cycle - the smallest repeated time intervals or operating time of the product, during which all established types of repairs are carried out in a certain sequence in accordance with the requirements of the regulatory and technical documentation.

Post-repair warranty period - the time during which the repair contractor guarantees the fulfillment of the established requirements for the product, provided that the consumer complies with the rules of operation, including the rules of storage and transportation.

Reliability - the property of the equipment to perform the specified functions, keeping in time the values ​ ​ of the established operational parameters within the specified limits corresponding to the specified modes and conditions of use, maintenance, repairs, storage and transportation.

Durability - the property of the equipment to maintain operability until the limit state occurs with the installed maintenance and repair system.