Synchronization in multi-motor hydromechanical systems

Introduction. The paper submits the analysis of existing design solutions of flow dividers used to synchronize hydraulic drives of working bodies of technological and mobile machines. The market demands for multithreaded throttle flow dividers without valves with the controlled division ratio, such as multi-axle vehicle chassis, are identified. The objective of the work was to analyze the possibility and rationale for developing a throttle four-way flow divider without valves with sensing elements of the Venturi tube type. The solution should provide the synchronicity of movement (rotation) of more than three working bodies of technological and mobile machines.Materials and Methods. A patent search for the designs of hydraulic flow dividers is carried out, and systems that require the division of the hydraulic fluid flow into more than two executive bodies are considered. An upgrade option, which allows dividing the flow into four branches, is proposed for the design of a three-channel throttle flow divider without valves.Results. The urgency of developing a multithreaded throttle flow divider without valves for application in industrial and mobile machines is validated. Two types of four-flow dividers are considered, their weaknesses are indicated. It is noted that the development of a multithreaded throttle flow divider based on the designs created in 1989 and 1991 will reduce the number of hydraulic pumps and get rid of the series connection of double-flow dividers. In this way, it is possible to reduce pressure losses in the hydraulic system and implement adaptive control of hydraulic motors of multi-motor mobile machines. The possibility to obtain a divider/combiner into four flows by adding an outlet chamber connected to the membrane chamber through a channel entering the Venturi nozzle on the basis of a three-flow throttle divider is shown. The principle of operation of such equipment is described.Discussion and Conclusions. The principles of construction of throttle flow dividers without valves are considered. An upgrade option is proposed to increase the number of division channels from three to four. However, to validate the operability of this design, a numerical analysis of the various modes of operation of the divider is required — calculation of the reduced volumetric stiffness of its working cavities. The information obtained can be used to modernize the hydraulic units of technological and mobile machines, increase their reliability, manufacturability, and efficiency. The issues that need to be solved in further research are identified.

Measuring system for monitoring the polydimensional deformation of superstructures of bridges and over-bridges improvement of volume hydraulic drive construction and road machines using flow shareholders

Due to its advantages, the hydraulic drive is widely used in road construction machines. Depending on its design, the share of the hydraulic drive, which is the most expensive unit of a road construction machine, accounts for thirty to eighty percent of all failures. Reliable hydraulic drive, provides, to a large extent, the reliability of the whole machine and the efficiency of the construction organization as a whole. The efficiency of the hydraulic drive of construction machines, and, as a consequence, the machines themselves, is ensured by a set of measures, among which the most important is the quality design, manufacture and operation, combined into a single structural system. Depending on the quality of cleaning of the working fluid, the service life of hydraulic machines can be increased or decreased several times. Accumulation of pollutants in the hydraulic drive, the hardness of which is significantly higher than the hardness of metals, causes rapid wear of the surfaces of hydraulic units and the service life is rapidly reduced. Cavitation in the pump is accompanied by a pulsation of fluid pressure and noise. These pulsations are due to the return flow of fluid from the discharge cavity of the pump, which is accompanied by hydraulic shocks and as a result of alternating shocks, a pressure pulsation in the discharge line of the pump. The amplitude of these pulsations can, under known conditions, reach a value that causes the destruction of the pump. The possibility of cavitation can be reduced by rational choice of modes of operation of the hydraulic system and the correct design of its units, but this phenomenon can be completely eliminated only by using auxiliary pumping pumps, as well as increasing the pressure in the suction line of the pump. On the basis of the analysis of perspective directions of improvement of the hydraulic drive of the excavator the following improved scheme of it is developed. Usually only high-flow hydraulic motors can be used in flow dividers. But in our case it is necessary that the device had, first of all, small mechanical losses and small cost, and accuracy of division of working liquid which follows on filters can be small. In the volume flow divider, hydraulic motors are used: gear, piston, vane, screw, roller. The simplest dividers of volume type are paired (connected by shafts) hydraulic motors of lamellar (vane) and roller types. Hydraulic motors in this scheme are flow measuring devices (dispensers), which supply for one revolution the volume of liquid, equal without taking into account the leaks in the hydraulic motor, its working volume. The use of a flow divider as a source of hydraulic energy makes it possible to improve the hydraulic drive by combining in a single system the purification of the working fluid and the ejector feed of the pump. The most promising, in terms of cost, are flow dividers based on vane and rotary hydraulic motors..

Design And Control System of Automatic Control System of Coal Flow on Belt Conveyor Installation

In a power plant unit whose main fuel is coal, there is generally use a belt conveyor installation. This conveyor belt serves to supply coal from the crusher unit to the combustion chamber of the power generation unit. In this study, we discuss a case where the installation of a belt conveyor which was initially only one line was then made a new branch that supplies coal to other power generating units. Equitable capacity distribution and continuity of coal distribution are the main focus of this study. Therefore, a design of automatic control system of coal flow divider on belt conveyor installation was designed. The working principle of this coal flow splitting system is to control the movement of the straight blade plough that directs the flow of coal to each unit at the certain time and continuously. Straight blade plough in the form of steel metal plate with a thickness of about 10 millimeters in which one end is connected to the end of the pneumatic cylinder. Automatic control system of coal flow divider in belt conveyor installation designed using CX-Programmer and CX-Designer applications. CX-Programmer serves to create automatic control logic concepts. While the CX-designer functions to create a Human Machine Interface (HMI), making it easier for operators to control the course of the coal supply process. The results of this study are in the form of control logic lines that can be applied to Programmable Logic Control (PLC) device and Human Machine Interface (HMI) equipment.

Analysis of a New SEN Design with an Inner Flow Divider

To minimize the product imperfections due to slag entrapment and surface defects, the fluid flow pattern inside the mold must be symmetric, commonly named double-roll flow. Thus, the liquid steel must enter into the mold evenly distributed. The submerged entry nozzle (SEN) is crucial in product quality in vertical steel slab continuous casting machines because it distributes the molten steel from the tundish into the mold. This work evaluates the performance of a novel bifurcated nozzle design named “SEN with flow divider”. The symmetry at the outlet ports is obtained by imposing symmetry inside the SEN. The flow divider is a solid barrier attached at the SEN bottom inner wall, the height of which slightly surpasses the upper edges of the outlet ports. The performance analysis is done first using numerical simulations, where the Computational Fluid Dynamics (CFD) technique and the Smoothed Particle Hydrodynamics (SPH) approach are used. Then, experimental tests on a scaled model are also used to evaluate the SEN performance. Numerical and physical simulations showed that the flow divider considerably reduces the SEN outlet jets’ broadness and misalignment, producing compact, aligned, and symmetric jets. Therefore, the SEN design analyzed in this work is a promising alternative to improve process profitability.

Treatment of Complete Displacement of the Bilateral Legs into an Aortic Aneurysm Using an Iliac Branch Device

Purpose: Migration is a major cause of reintervention after endovascular aneurysm repair (EVAR). In patients with common iliac artery (CIA) dilation due to proximal migration of the iliac limb, internal iliac blood flow can be preserved by implanting an iliac branch device (IBD). Case Report: In this report, we discuss the case of a patient in whom the bilateral limbs were completely displaced into the aortic aneurysm due to proximal migration of the iliac limb after EVAR. By taking advantage of the characteristics of this migration, we formed a pull-through wire through the native terminal aorta without passing through the flow divider of the stent graft, and the IBD was deployed safely. Conclusion: The present case indicates that the preservation of at least 1 internal iliac artery is possible in patients with CIA dilation due to proximal migration of the iliac limb. However, the unique features of each case must be considered to determine the appropriate approach.

INVESTIGATION OF TRANSITIONAL PROCESSES IN THE ADAPTIVE SYSTEM OF HYDRAULIC DRIVES OF THE MECHANISM FOR CUTTING AND UNLOADING STALK FODDER

The problem of creating an energy-efficient and competitive mechanism for cutting and unloading stalk fodder from trench storage, by developing and justifying the parameters and modes of operation of the adaptive system of hydraulic drives of the mechanism is researched. The principal implementation of the adaptive system of hydraulic drive of the mechanism for cutting and unloading is proposed, in which a spool flow divider is placed between two executive hydraulic motors, which allows to regulate the supply of a U–shaped frame according to the load change which affects the cutting mechanism. The adaptive system of the hydraulic drive of the mechanism allows to stabilize energy consumption for separation of a portion of a stalk fodder under the condition of change and fluctuation of parameters which essentially influence the process of separation and unloading of a stalk fodder from the monolith. The transients in the adaptive systems of hydraulic drives of the mechanism for cutting and unloading of stalk fodder are received and analyzed. As a result of the study, it was found that by changing the operating widths of the slide valve of the separator in the direction of reduction, a significant increase in the responsiveness of the hydraulic drive system of the mechanism for cutting and unloading to the changes in the loading on the cutting apparatus. As a result, the range of the adjustment of the feeding of the hydraulic cylinder of the U–shaped frame, which increases the efficiency of stabilizing the separation process from the monolith of block-portion of stalk fodder with a minimum power of the hydraulic drive system, is substantially expanded. It is noted that the dynamic characteristics of the hydraulic drive of the mechanism for cutting and unloading stalk fodder adaptive to the load are influenced by the design parameters of the spool flow divider which implements feedback. On the basis of the conducted experimental research recommendations on the choice of constructive parameters of the spool flow divider are given.

Influence of Flow Divider on Overall Efficiency of a Hydrostatic Drivetrain of a Skid-Steer All-Wheel Drive Multiple-Axle Vehicle

The efficiency of a skid-steer, all-wheel drive, multiple-axle vehicle with a hydrostatic drivetrain equipped with low-speed motors when it operates on soft terrain was studied. A flow divider enables a single pump to simultaneously power more than one motor circuit with different pressures in each. It prevents kinematic discrepancy and improves vehicle mobility. There are two types of flow divider: spool type and gear type, where each type has its own set of performance characteristics, such as flow range, pressure drop, accuracy and application parameters. In the present work, the influence of the characteristics of both types of flow divider on overall vehicle driveline efficacy is described.

Application Based Performance Analysis of a Priority Flow Divider Valve Using Power Hydraulic Systems

Priority flow divider valve (PFDV) splits the flow in two different paths: Primary flow path and Secondary flow path. It can be used in twice applications: a system needs to perform dual functions against dual loads simultaneously and to obtain a stable flow by supplying a compensated flow from secondary flow line to the primary flow line using an energy storage device and a control valve. Two different hydraulic systems are identified to analyze the steady and dynamic performance of the PFDV. The first hydraulic system with PFDV is designed for automobile steering system with a load sensing control strategy in the presence of multiple actuators whereas second system is designed for wind turbine hydraulic power transmission to obtain stable power from it in the absence of generator. Both power hydraulic systems are modeled using bond graph technique and simulated in SYMBOLS SHAKTI software to analyze the PFDV performance.