Reliability of the belt conveyor bed when restoring failed roller supports

The reliability of modern belt conveyors, whose length reaches tens of kilometers, is primarily determined by the reliability of the roller supports that support the belt and ensure its movement. As they wear out, some roller bearings fail and need to be repaired or replaced. The dynamics of the number of working roller supports is determined by the system of Kolmogorov equations. Their solution allows us to find the probabilities of finding the system in states with a different number of working elements. The article finds probabilities for two cases. In the first case, when restoring, only one roller support is repaired each time. In the second case, all roller supports are repaired or replaced. In the case of sequential recovery, the mathematical expectation of the number of properly working roller supports may be less than the total number by several units. There are always elements that need to be repaired. If the recovery rate of the elements is many times higher than the failure rate, the mathematical expectation of the number of properly operating roller supports is less than the total number of roller supports by less than one, during most of the time all roller supports are serviceable. In the case of simultaneous recovery of elements, an equally high level of reliability is achieved even with comparable failure and recovery rates. The results obtained can be used to determine the necessary reserve of spare structural elements and to plan the maintenance of conveyors.

Slippery damper of an overlay for arresting and manipulating droplets on nonwetting surfaces

In diverse processes, such as fertilization, insecticides, and cooling, liquid delivery is compromised by the super-repellency of receiving surfaces, including super-hydro-/omni-phobic and superheated types, a consequence of intercalated air pockets or vapor cushions that promote droplet rebounds as floating mass-spring systems. By simply overlaying impacting droplets with a tiny amount of lubricant (less than 0.1 vol% of the droplet), their interfacial properties are modified in such a way that damper-roller support is attached to the mass-spring system. The overlayers suppress the out-of-plane rebounds by slowing the departing droplets through viscous dissipation and sustain the droplets’ in-plane mobility through self-lubrication, a preferential state for scenarios such as shedding of liquid in spray cooling and repositioning of droplets in printing. The footprint of our method can be made to be minimal, circumventing surface contamination and toxification. Our method enables multifunctional and dynamic control of droplets that impact different types of nonwetting surfaces.

Vibration of an axially loaded heterogeneous pinned-pinned beam with an intermediate roller support

The present paper is devoted to the issue of what effect the axial load (compressive or tensile) has on the eigenfrequencies of a heterogeneous pinned-pinned beam with an intermediate roller support (called a PrsP beam). This problem is a three point boundary value problem (eigenvalue problem) associated with homogeneous boundary conditions. If the Green functions of the three point boundary value problem (BVP) are known the eigenvalue problem that provide the eigenfrequencies for the beam loaded axially can be transformed into an eigenvalue problem governed by a homogeneous Fredholm integral equation. The later eigenvalue problems can be reduced to an algebraic eigenvalue problem which then can be solved numerically by using an effective solution algorithm which is based on the boundary element method.

DESIGN AND PRODUCT DESIGN IN CAD/CAM/CAE NX SYSTEM MANAGED BY TEAMCENTER PLM SYSTEM

The article discusses a system widely implemented in the designing of equipment for the NX construction industry. Along with this system, a modern automation tool was used. The most common and most used products are Siemens products: PLM-system "Teamcenter". The functionality of this configuration is huge, it includes such applications a "Manager of Structure", "Classifier", "Advanced Studio", "Ray Tracing Studio", etc. For example, it is possible to create a single product structure with various configurations, machine components and assemblies, using the "Structure Manager". This structure allows to simplify the introduction of changes and the development of a digital electronic model. For the final visualization and rendering, the NX system provides a certain set of tools, which includes "Extended Studio" and "Ray Tracing Studio". "Advanced Studio" is an application allowing to get high-quality image, including the effects of materials, textures, lighting, shadows and reflections for the product in the CAD/CAM/CAE NX system. "Ray Tracing Studio" allows to get the rendering of the future product. In the Ray Tracing Studio editor, it is possible to configure such parameters as dynamic tracing setting, real-time ray tracing setting, display static high-quality tracing setting, and general display settings. Creation of a product in this system can be considered by the example of a digital electronic model of a roller support.

DETERMINATION OF THE CHANGE OF THE DESIGN POSITION OF THE PROFILE OF THE BELT CONVEYOR ON THE LOAD OF THE ROLLER BEARINGS

The article attempts to establish the basic patterns in the formation of loads in the structure of the conveyor frame due to changes in the design position of the constituent elements based on analytical calculations. The amortization replacement of rollers and the establishment of a change in the projected resource caused the change in the design position.The aim of the work is to study the interaction of the elements of the belt conveyor on the convex region of the profile when the design position changes and to determine the change in the resource of the roller support elements. The purpose of the work is formulated from the analysis of unplanned stops and premature replacement of conveyor elements, in particular conveyor rollers, on the convex region of the profile.To achieve this goal the influence of the geometric parameters of the convex section of the belt conveyor profile on the force interaction of the belt and roller supports was considered, and the change in the resource of the roller bearings was determined.To characterize the geometric parameters of the convex section of the belt conveyor, the following were selected: the number of roller supports, the distance between the roller supports, the radius of curvature of the conveyor profile, the angle of the curved section. The mathematical model is based on the belt equilibrium equation, which contains the tension forces of the conveyor belt and the forces from the action of roller supports. Particular attention is paid to establishing the effect of changing the geometric parameters of the convex section on the roller bearing life. It has been established that a decrease in the radius of the transitional convex section as a result of a change in the initial design position by 2.4 times leads to an increase in the force acting on the roller support by 161%. It was found that the increase in force is the reason for the rapid exit from the operational state of the rolling bearings of the roller bearings, as evidenced by the intensive drop in the resource of the rollers (18 times).The proposed algorithm for determining the main parameters of the force interaction of the elements of the belt conveyor on the convex region of the profile will make it possible to predict the resource and prevent the conveyor from leaving the premature operational state.

PENERAPAN METODE RELIABILITY CENTERED MAINTENANCE (RCM) PADA PERAWATAN MESIN CONVEYOR UNLOADING PHOSPHATE ROCK (Studi Kasus PT PETROKIMIA GRESIK)

Proses bongkar material bahan baku pupuk merupakan proses yang penting dalam operasional PT Petrokimia Gresik. Dalam proses distribusi atau pengangkutan raw material dari pelabuhan menuju gudang pabrik atau ruang produksi, salah satu peralatan utama yang digunakan adalah conveyor. Selama ini, conveyor 02M603 yang digunakan dalam proses bongkar di pelabuhan PT Petrokimia masih sering mengalami kerusakan sehingga menimbulkan kerugian salah satunya dalam bentuk biaya demurrage. Solusi dari permasalahan ini ialah memberikan usulan rencana jadwal perawatan mesin dengan menggunakan metode reliability centered maintenance. Hasil penerapan metode Reliability Centered maintenance diperoleh empat komponen yang harus dirawat secara terjadwal (time directed) yaitu: carrier roller, support carrier, impact roller dan rubber seal. Komponen-komponen tersebut merupakan komponen yang paling sering mengalami kerusakan dan menyebabkan downtime pada conveyor 02M603. Berdasarkan hasil analisis diusulkan agar perawatan dilakukan bukan selama 100 jam atau setiap 1 kali bongkar karena salah satu komponen, yaitu carrier roller memiliki nilai MTTF dibawah 200 jam, sehingga apabila perawatan dilaksanakan tiap 200 jam dapat memperbesar kemungkinan terjadinya downtime akibat kerusakan carrier roller.

Analysis of Functionally Graded Timoshenko Beams by Using Peridynamics

In this study, a new peridynamic formulation is presented for functionally graded Timoshenko beams. The governing equations of the peridynamic formulation are obtained by utilising Euler-Lagrange equation and Taylor’s expansion. The proposed formulation is validated by considering a Timoshenko beam subjected to different boundary conditions including pinned support-roller support, clamped-roller support and clamped-free boundary conditions. Results from peridynamics are compared against finite element analysis results. A very good agreement is obtained for transverse displacements, rotations and axial displacements along the beam.

Experimental evaluation of the load capacity of the rollers of gravity conveyors for pallets

The main approaches to calculating the load capacity of the carrying rollers of gravity conveyors are presented. It is shown that in practice, in the designs of modern non-driven conveyors for pal-lets, the priority when choosing the pitch of the carrier rollers is the stability of the movement of the load, rather than minimizing the number of rollers. In connection with the urgent task of reducing the metal consumption and the cost of gravity roller conveyors for pallets, the purpose of the work is to experimentally determine the load capacity of the rollers of gravity conveyors for pallets with plastic bearing housings. The experimental studies were carried out in the laboratory of the Depart-ment of Applied Mechanics on a Galdabini Quasar 50 universal testing machine using a special roller support for two roller designs - with a solid axis and on half-axles. The test results showed that the stiffness of a roller with a solid axis in the load range up to 670 N is about 1358.4 N / mm, and in the load range from 670 to 1500 N - 2229.9 N / mm. The rigidity of the roller on the axle shafts in the entire load range is 2048.0 N / mm. The analysis of the obtained results showed that for loads over 670N the use of the axle slightly increases the stiffness coefficient, and, on the contrary, it decreases in the load range up to 670N. In order to reduce the cost of carrying rollers with plastic bearing housings, it is advisable to use a design on semi-axles.

Determination of the loads on the rollers of the tubular belt conveyor

The article presents methods for determining loads on rollers of a six-roll support of a tubular belt conveyor, based on the equilibrium laws of elastic cylindrical plates and shells filled with a freight. In this case, the forces acting on the rollers of the tubular conveyor are the sum of the forces caused by the weight and expansion of the bulk load, the weight and bend of the belt, as well as the inertial forces associated with the curvature and the deflection of the belt under the weight of the bulk load. The dynamic forces acting on the rollers as the belt moves are determined from the equation of the oscillations of a heavy flexible string using the Ritz method. As a result of the research, analytical dependences of the forces acting on the rollers of the six-roller support of the tubular conveyor on the parameters of the conveyor, the belt, the properties of the bulk load and the radius of curvature of the conveyor are obtained, and an assessment of the component these forces is given. The results can be used to determine the parameters of the tubular conveyors rollers and increase the service life of the rollers.

PENGARUH NORMALIZING TERHADAP BAJA 20Mn Cr6 HASIL PENGECORAN UNTUK SUPPORT ROLLER

Rotary Kiln machine is used in fertilizer plant which is function to mix the fertilizer ingredients. Part of the Rotary Kiln is support by using a roller. Support roller is made of 20MnCr6 material, AISI 5120 (0.18% C) with casting process. Normalizing phase on casting processes is using to increase strength of the material The objectives of the normalizes process is to eliminate residual stresses, softening, increasing toughness, homogenization of micro structures and to ease machining processes. The effect of normalizing can be measured by using mechanical test, ie tensile test, hardness test and microstructure analysis. Test specimens were made the same material with normalizing and without normalizing process. Normalizing process temperature at 900oC heating for 150 minutes with air cooling for 7 hours. The results has shown that normalizing material has lowest tensile strength of 41.05 kgf/mm2 is compared to 42.16 kgf/mm2. However, the ductile fracture is higher 41.2% is compared to 29.52%, the microstructure formed uniformly evenly compared without normalizing. The softening process also makes the roller support rotate due to rubbing with riding ring.