Edge Of Bucket Research Articles

Synthesis of basic geometry parameters of excavator working equipment

Problem. Single-bucket excavators have become one of the most popular machines today, which are widely used to perform a variety of construction works. The working area or service area is one of the main characteristics of the work equipment of the manipulation type. It must meet certain requirements, which are: the largest digging depth, unloading height and digging radius at the level of the parking lot. To ensure the parameters of the given working area, it is necessary to correctly select the basic geometry of the working equipment: the length of the boom and the handle, the turning radius of the bucket edge. Goal. The purpose of the work is to automate the synthesis of basic geometry parameters of the hydraulic excavators, according to the specified parameters of the service area (working area). Methodology. A system of non-linear equations establishing a relationship between the geometric parameters of the working equipment and the parameters of the working area was obtained. Results. The software for the OS Windows was developed. The program outputs not only numerical results. To visualize them, contours of the resulting working area are built. Originality. The relationship between the geometric parameters of the working equipment and the parameters of the working area has been established. A mathematical model and software for automating the synthesis of geometric parameters of working equipment have been developed. Practical value. The developed software can be applied not only at the design stages of new types of excavator working equipment, but also in the process of preparing the machine for specific types of work. The proposed approach can also be extended to the synthesis of parameters of the lever mechanisms of other construction machines, in particular, the working equipment of loaders, looseners, etc.

Определение оптимальной силы и скорости копания грунта одноковшового гидравлического экскаватора с ковшом сферической формы

Introduction. The paper describes the scope and purpose of single-bucket hydraulic excavators. The method of digging a single-bucket excavator with a bucket of spherical shape, which allows to increase productivity, is considered. The urgency of increasing the productivity of these machines is formulated. The purpose of the work: to determine the optimal strength and speed of digging the soil of a single-bucket hydraulic excavator with a spherical bucket. Research methodology. To confirm the effectiveness of the proposed bucket design, a diagram of the forces acting on it during digging is presented. The rheological model of the process of digging with a bucket of spherical shape is considered. A mathematical model in the form of a system of second-order differential equations has been compiled on the basis of the force scheme and the rheological model. Research results. A mathematical model has been identified that makes it possible to calculate the dependence of the speed and optimal force when digging the soil with a spherical bucket of a single-bucket hydraulic excavator, depending on the design parameters of the bucket and the parameters of the soil. The dependence for determining the friction force of the soil inside the bucket arising during digging is given. The dependencies for determining the weight of the soil in the bucket and the bucket itself are described. The dependence for calculating the lateral pressure of the soil using a stabilometer is given. The dependences of the calculation of the friction force of the external soil on the bucket and the friction force of the external soil on the soil in front of the bucket edge are presented. A dependence for determining the normal force from the external soil to the compacted soil in front of the bucket edge is proposed. The concept of a "compacted core of the soil" in front of the bucket edge is given and the dependence for determining its depth is given, however, a more precise definition of the latter requires additional research. A dependence is proposed for determining the mass of soil located in front of the bucket edge. The conditions for the possibility of digging the soil are accepted, in which the digging speed is greater than zero, and the digging force is minimal. An algorithm is described that allows you to select the minimum force for the digging process based on the dependencies given in the work. A block diagram of the algorithm for selecting the minimum force for the process of digging with a spherical bucket is given. The selection of the minimum digging force will confirm the effectiveness of a single-bucket hydraulic excavator with a spherical bucket.

Determination of the Bucket Wheel Drive Power by Computer Modeling Based on Specific Energy Consumption and Cutting Geometry

Starting from the general principles of material cutting, with applicability to coal and overburden excavation using bucket wheel excavators (BWEs), this paper proposes another method for calculating the drive power of the bucket wheel excavator by computer modeling. This approach required two steps. In the first step, the volume of the excavated material for one slewing movement of the boom and for a particular excavation geometry was determined, and the slewing time in the open pit coal mine was measured. In the second one, the values of the specific energy (SE) consumption for cutting were determined by laboratory tests on samples of material taken from the open pit mine. The proposed method allows for the estimation of the load of the bucket wheel drive motor by taking into account only the specific energy necessary for the cutting of the material, the excavated volume during one slewing, and the time required to excavate this volume, and not the wear coefficients of the teeth or bucket edge. This method is important for establishing the correlation between the height of the excavated slice and the slewing speed of the boom in order to optimize the drive power of the bucket wheel and thus improve energy efficiency, increase the performance of excavators, and reduce operating costs.

Comparison of laboratory wear test results with the in-service performance of cutting edges of loader buckets

The in-service cutting edge of a mining loader bucket was investigated and its wear behavior compared with samples tested in the laboratory to assess how well the wear testing methods correlate with the in-service conditions. The examined in-service cutting edge of a bucket made of a wear resistant steel had been run in an underground mine with quarry gravel. The wear behavior of the cutting edge was simulated in the laboratory scale with several application oriented abrasive and impact-abrasive wear testing methods. In addition to the contact mode, high loads, large abrasive size, abrasive type, and the comminution of the abrasive formed the basis for the design of the laboratory experiments. The wear surfaces and cross-sections of the original cutting edge and the test samples were characterized, and the wear behaviors were compared with each other. Work hardening of the steels occurred in all cases, but the amount of plastic deformation and the depth of the wear scars varied.

CFD Analysis of Flow Physics and Aerodynamic Performance of a Combined Three-Bucket Savonius and Three-Bladed Darrieus Turbine

In this paper, the performance of a combined three-bucket Savonius and three-bladed Darrieus turbine was analyzed computationally by using Fluent 6.2 CFD software. Two-dimensional steady-state CFD simulations were performed for without overlap, and with five overlaps namely 16.2%, 20%, 25%, 30%, and 35%. The flow physics of the combined turbine was analyzed with the help of pressure, velocity and vorticity contours. Further, the aerodynamic coefficients were evaluated with respect to angle of attack for various tip speed ratios. It was concluded that the power augmentation of the combined turbine occurred for low overlap in Savonius turbine due to high aerodynamic lift-to-drag coefficient of the Savonius turbine, caused by the increase of dynamic pressure from bucket-vortex interactions on the concave face of the returning bucket. And it also occurred for high aerodynamic lift-to-drag coefficient (14.5) of the Darrieus turbine from the increase of velocity difference across the Darrieus blade with small overlap (16.2%) in Savonius turbine. For without or with low overlap (16.2%), coanda flow occurred across the overlap between the inner edge of bucket and the central shaft that migrated from the downstream side of the advancing bucket towards the upstream side and then reached the concave face of the returning bucket increasing dynamic pressure on it, and hence augmented power production for the combined turbine. However, high value of overlap (20% onwards) caused vortex separations from the inner edges of bucket destabilizing the coanda flow for which the aerodynamic coefficients were lowered.

Application of siphon principle to fluid drainage in transurethral surgery

Transurethral resection is usually performed using an all-in-one drape with a fluid collection pouch, drainage port and hose. Gravity drainage of irrigation fluid through the hose is often hampered, resulting in fluid retention in the pouch. We applied a siphon principle to facilitate fluid drainage by making a U-shaped bend near the distal end of the hose, using an adhesive tape, and hooking the distal end of inverted U shape on the edge of bucket placed on the floor. When the hose is filled with irrigation fluid up to the crest of the siphon, fluid flow driven by atmospheric pressure continues until the pouch is evacuated. Repriming and restarting occur automatically throughout the operation. This simple device has virtually eliminated fluid retention in the pouch and proved to be especially useful in transurethral prostatectomy, which requires a large amount of irrigation fluid.

On the Discharge from the Bucket of the Bucket Elevator

The handling capacity of a vertical bucket grain elevator of centrifugal discharge type, which was deficient owing to the lower discharge efficiency, was considerably improved by changing the shape of the bucket. Further researches on the behavior of grain until the discharge which had caused the improvement were carried out on a model equipment and the following results were obtained. In regard to the discharge efficiency the bottom and top angles of the bucket are essential and those exceeding 25° and 70° respectively seem to be more favourable. If the bottom angle is smaller than 25°, some part falls out before reaching the chute ; if the top angle is smaller than 70°, some quantity is overflowed before the bucket arrives at the top position. Discharge takes place mostly passing closely over the bucket edge in an approximately parabolic motion with a initial velocity nearly equal to the circumferential velocity of the edge.

On the Discharge from the Bucket of the Bucket Elevator

The handling capacity of a vertical bucket grain elevator of centrifugal discharge type, which was deficient owing to the lower discharge efficiency, was considerably improved by changing the shape of the bucket. Further researches on the behavior of grain until the discharge which had caused the improvement were carried out on a model equipment and the following results were obtained. In regard to the discharge efficiency the bottom and top angles of the bucket are essential and those exceeding 25° and 70° respectively seem to be more favourable. If the bottom angle is smaller than 25°, some part falls out before reaching the chute ; if the top angle is smaller than 70°, some quantity is overflowed before the bucket arrives at the top position. Discharge takes place mostly passing closely over the bucket edge in an approximately parabolic motion with a initial velocity nearly equal to the circumferential velocity of the edge.