Two-roller gear crusher

Introduction

The complex of works performed in a certain sequence, ensuring the restoration of the machine, is the technological process of repair.

The scope, nature and sequence of repair, the structure of the machines depends on the design features of the machines, the production capabilities of the repair personnel and the method of repair. Therefore, in order to cover all repair operations and carry out them in sequence, ensuring the high quality of the work performed. It is necessary to think through the technical process of repair, constantly take care of its implementation, for this it is necessary design and technical preparation of repair.

Design preparation consisting in provision of technical documentation (working drawings of repaired machines, technical specifications for repair, instructions and books of rejection cards, etc.).

Process preparation includes the development of the process for the repair of the main parts, the design and manufacture of a special measuring tool and devices, the compilation of specifications and the determination of consumption rates for material, parts, units, devices and tools.

Depending on the repair method used in the plant, the repair process may vary. It should include: handover of the machine, control and sorting of parts by serviceability, assembly of units and machines as a whole, testing of repaired machines, painting and acceptance of machines from repair.

The most important factors determining the operational reliability and service life of transport and process machines and equipment are the operational properties of the surface layer of the material and its strength. During operation, the working surfaces of the parts often wear out, which requires their complete replacement and, as a result, an increase in the cost of repair. In some cases, the entire manufacture of parts is generally irrational due to the high cost of materials and the difficulty of processing. Therefore, to solve the problems of increasing the physical and mechanical parameters of the working surfaces of parts and increasing their service life, various methods of restoration and surface hardening are used in machine building and service enterprises.

A large reserve of technical service enterprises is the organization of restoration of worn out parts. Increasing the recovery volume of parts significantly reduces the cost of spare parts, and therefore the cost of repairs and services in general.

Description of the arrangement and operation of the twin roll crusher

Two-roll toothed crusher is widely used in the construction materials industry, especially in the grinding of viscous and wet materials. The two-roll toothed crusher is located in the grinding shop.

The working element in the two-roll toothed crusher is two rolls rotating towards each other and extended by a distance determined by the maximum size of the incoming product. Material to be crushed is tightened between rolls due to friction and is gradually crushed. Motor power of high-speed roller is 90 kW, motor power of slow-speed roller is 20 kW. The capacity was 2530t/h. The degree of grinding depending on the properties of the crushed material for hard rocks is from 4 to 6, for soft, viscous 712 or more. The crusher operates under dusty conditions. A particular type of wear is mechanical wear, which occurs as a result of the abrasive material entering the parts of the crusher. Two major repairs are carried out.

The actions of the crusher rolls are based on the principle of splitting and breaking the pieces between the rolls rotating towards each other. Bearings in which shaft of first roll rotates are rigidly fixed on base of welded metal structure. Bearing of second roll is retained by springs, shafts and other parts. Rotation of rolls is carried out from motors through V-belt gears.

Recovery Job Instruction for Twin Roll Gear Crusher Part

1.9.1 Basic types of defects

Shaft defects: shaft bending, bearing neck wear.

Shaft or axle parts are present in any mechanism and play an important role in ensuring functional operability of assemblies and assemblies. During operation, shafts and axles are subjected to operational loads, as a result of which defects can occur, the main of which are given in the article. Existing methods for eliminating shaft and axle defects have their own characteristics, which must be taken into account when choosing the repair and restoration technology. Keywords: defect, repair, restoration, surfacing, spraying, electroplating, polymer compositions. Parts of the "shaft" type include parts of machines designed to transmit torque and perceive active forces from parts and supports located on it. Pulleys, gears, flywheels, etc. are attached to the shaft. Some of these parts, called drive parts, receive rotational movement from an external energy source (engine). Rotation is transmitted to other parts by shaft. They are called wingmen. Thus, the shaft, when moving, necessarily transmits a force (torque), and therefore experiences torsion and bending deformations. Shafts in shape are divided into straight or curved (cranked), whole or compound (assembled from several parts), solid or hollow (hollow). Shafts and axles receive large loads during operation. Therefore, they are made of carbon structural steel, subjected to pressure treatment, surface cementation, quenching and tested for strength. A properly designed shaft is a beam of equal resistance. Shafts and axles rotate, and therefore experience alternating loads, stresses, and deformations. Therefore, breakdowns of shafts and axles have a fatigue character. The main defects of shafts and axes include:

Wear and balls of support necks. Generally, there is a lack of lubrication between the friction surfaces at a high rotational speed.

Deflections, bends, and twists. They are formed when the limit loads on the shaft or axle are exceeded, or if they overheat during operation .

Cracks. They arise mainly from the impact and vibration loads, are quite difficult to detect and can lead to emergency wear and failure of the unit or mechanism.

Destruction of threaded surfaces. Most often, there is a cut and crush of the thread as a result of sharp axial loading or when increased torque occurs on the threaded connection.

Destruction of key or spline slots. It also occurs at impact and vibration loads or when the permissible torque values ​ ​ at the key or spline connection are exceeded.

Working of surfaces for rubber reinforced cuffs (glands). Occurs as a result of mechanical, abrasive or erosive action. Defects and restoration of shafts and axles are carried out during major or current repairs of cars. The shafts and axes are selected based on the results of measurements, visual inspection and the results of metallographic studies (if necessary). If it is possible to restore the shaft or axle, a decision is made on the method of restoration and repair.

The repair plant currently has a sufficient number of methods to repair almost any worn and damaged part. But for practical use, it is necessary to choose one, the application of which is technically possible and most economically feasible. Choosing an effective method of restoring parts is an important task to improve the organization of repair production. The choice of the method of restoring parts is influenced by: the type of defect and the amount of wear; Material, size, shape, and mass of the part accuracy and type of processing; specialization of production, equipment availability; cost of recovery, and service life of restored parts.

2 organizational part

2.1 Types and content of repairs of two-roll toothed crusher

Repair services shall be performed once a month to restore the technical state of the equipment that resulted from its operation during the period prior to this scheduled repair and shall ensure that the equipment is operated without failure until the next repair.

Current (small) repair is the smallest type of scheduled repair in terms of volume, in which due to adjustment of mechanisms, replacement and repair of quickly worn parts, normal operation of the machine is ensured until the next scheduled repair.

Average repair - average in volume and complexity type of planned repairs of the machine. Its purpose is a limited restoration of the machine's resource and ensuring its operation before the next scheduled repair. Simultaneously with the average repair of the mechanical part, for example, lifting and transportation machines, as a rule, overhaul of electric engines is carried out, including their disassembly and impregnation of the windings with hot insulation varnishes, drying in furnaces, assembly and testing .

Overhaul is the most complex and time-consuming type of planned repair of the machine. Its purpose is full or close to full (not lower than 0.8 machine life up to the first 18)

overhaul) restoration of machine life. During overhaul, the machine is completely disassembled into units and parts, washed, dried, defective parts, restored, assembled, painted, tested and put into storage finished products with the execution of all regulatory and technical documentation.

Maintenance:

Cleaning of equipment from dust, dirt and process waste.

External inspection in order to detect defects of equipment and its individual units: motors, V-belt reduction gear, crusher casing, tensioner.

Opening of crusher hatches to inspect and check the condition of units and parts: gear rolls, bearings, etc. Check the status of loading and unloading devices.

Opening and detailed disassembly of individual units, the further operability of which causes doubt. When inspecting the rolls, evaluate the degree of wear of the teeth (restore worn teeth by welding).

Make sure that rolls are serviceable, make sure that units and parts are safely attached (tighten loose bolts).

Adjustment of clearances in equipment units and smooth running of movable conjugates. Check the clearance between the rollers, adjust it if necessary (the rollers must be installed reliably and correctly on the frame, the clearance between the rollers must be 20 mm).

Adjustment of couplings.

Check, tighten or replace collars and seals on gearbox shafts and roll shafts.

Serviceability check and adjustment of safety devices and locking systems.

Minor repair of the casing with replacement of its individual elements.

Washing and filling of lubricants and crankcase lubrication systems (bearings, reduction gear box).

Equipment assembly and idling testing.

Different types of testing.

Work on modernization of units and parts.

Overhaul:

Complete disassembly of the crusher by units.

Clarification of the list of defects with inclusion of previously unaccounted for repair works.

Restoration or replacement of worn-out units and parts, including basic: gearbox, tensioner, geared rolls assembly, safety device.

Repair or replacement of the foundation under the crusher.

Work on modernization of equipment and individual units.

Crusher assembly, fitting, adjustment of movable units and elements.

Replacement of damaged components: loading and unloading devices.

Restoration or replacement of fences.

Packing and painting of unprocessed crusher surfaces, replacement of plates and inventory numbers, restoration of inscriptions and indicators.

Adjustment and adjustment of equipment, testing.

2.2 Organization and technology of overhaul of two-roll toothed crusher

The main objective of the major repair of machines is to perform, at the lowest cost of time, labor and material and technical resources, the restoration of serviceability and full or at least 0.8 value of the resource installed for the new machine, with the replacement or restoration of any parts, including basic ones.

The feasibility of overhaul of machines is also due to the fact that in modern conditions of industrial development there is not yet and soon there will be the possibility of a complete replacement

worn out equipment for a new one. Often, using progressive methods of restoring and strengthening the surfaces of parts, the resource of the repaired machine is increased to the level of a new, and sometimes higher.

Equipment repair is effective when it is performed qualitatively, with the greatest savings in materials and labor. Premature equipment shutdowns for repairs and long delays in the start of planned repairs inevitably lead to higher repair costs. Untimely repair leads to progressive wear of units and parts and, as a result, to equipment accidents.

The quality of repair determines the technical condition and productivity of the equipment, thereby determining the appropriate level of its extensive and intensive use and, therefore, the volume of products produced. The duration of repair processes affects the level of extensive use of equipment, since the time of equipment shutdown for repair work is associated with it.

The effectiveness of capital repairs depends on a very large number of organizational and technical and economic factors: the repair organization system, the availability of high-precision technological and test equipment, the use of high technologies for restoring parts, the introduction of modern systems for evaluating, monitoring and managing the quality of products at repair enterprises.

The peculiarities of the enterprises "location, the conditions of their activity in terms of the continuity of the technological process of production of the main products, the dimensions of the repaired machines, equipment and units impose specific requirements for organizing and carrying out major repairs in various industries, which will be discussed below.

In the conditions of metallurgical plants, overhaul of large units is associated with certain difficulties. There is a need to simultaneously attract significant funds, to provide all areas of work with qualified workers. This causes difficulties in carrying out scheduled preventive repairs of other units. For major repairs, a significant number of employees of specialized trusts are used. In this regard, the improvement of the technology, organization and mechanization of major repairs of the main metallurgical units contributes to a significant reduction in the labor intensity of the repair work and its duration.

It should be noted that at the metallurgical enterprise there is a limit to the growth of the number of repair workers, since with a large increase it becomes unprofitable to maintain significant personnel of repair workers who cannot be fully loaded between major repairs.