Abstract
The sealing characteristics of the hydraulic cylinder in the hydraulic support will have an momentous implication on the safety and reliability of the whole system. The traditional test ...methods of the sealing characteristics of hydraulic support pure water hydraulic cylinder have many shortcomings, such as single means, complex process, poor accuracy and low efficiency. Based on this, this paper first analyzes the sealing principle and function of hydraulic support pure water hydraulic cylinder, then studies the CAT system of hydraulic support, and finally gives the design and utilization process of CAT system for sealing characteristics of hydraulic support pure water hydraulic cylinder.
•CFRP is used in the field of hydraulic cylinder to achieve the purpose of weight reduction.•A design method of radial stiffness of CFRP cylinder based on requirements of dynamic seal is proposed, ...which can map the low internal leakage performance of CFRP hydraulic cylinder. The composite structure of CFRP hydraulic cylinder tube is proposed for the special needs.•The experimental results support the performance of CFRP hydraulic cylinder for high pressure resistance, low leakage, low friction, and the weight loss effect is significant.
Hydraulic cylinders are widely used in mobile equipment such as aircraft, construction machinery, and heavy-duty robots. The large weight of the hydraulic cylinder seriously restricts the performance of the whole machine in terms of maneuverability, carrying capacity, endurance time, and energy saving. Using CFRP instead of metal can improve the weight reduction potential of a hydraulic cylinder. The law was found from the requirement for internal leakage prevention of hydraulic cylinder to the design of CFRP layer parameters. According to this law, the design method of radial stiffness of CFRP hydraulic cylinder is proposed. The composite structure of CFRP hydraulic cylinder was designed for the specific requirements of using CFRP to manufacture hydraulic cylinders. As an example, the prototype developed based on the radial stiffness design method and composite structure has reduced weight by 56.86% while maintaining the same performance as the conventional metal hydraulic cylinder. The light weighting of hydraulic cylinders brings considerable economic and environmental benefits.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The synchronous lifting process is a key technology for non-destructive salvage and smooth transfer of ancient ships and their internal cultural relics to the predetermined dock. This paper, starting ...with the principle of computer controlled hydraulic synchronous lifting technology, and taking the actual underwater synchronous lifting project of Sewol in South Korea as an example, demonstrates the feasibility of the technology transfer to the underwater cultural relic salvage project. In addition, it elaborates on the planning of the elevator arrangement, control actions, and system requirements for the integral salvage and relocation project of the ancient ship. Moreover, it introduces the construction implementation details of synchronous lifting equipment. The hydraulic lift follows vertical layout, and the hardware assembly involves the installation of steel strands, bottom anchors and brackets, hydraulic cylinders, control systems, and underwater pins. The success of the integral salvage of “Yangtze Rive
When a hydraulic cylinder connects two chambers directly to one or two hydraulic pumps driven by electric servo motors without any control valve in between, it can be called a motor-controlled ...hydraulic cylinder (MCC). Unlike valve-controlled cylinders, MCCs have no valve throttling, which significantly increases the energy efficiency. Among different MCC topologies, the two-motor-two-pump (2M2P) MCC has several advantages, such as cylinder pressure control and no mode switch oscillations. However, due to state coupling when controlling both piston position and minimum cylinder chamber pressure, the 2M2P MCC is a multi-input-multi-output (MIMO) system that usually requires advanced MIMO controller analysis and design. This paper presents a control algorithm for a 2M2P MCC with the minimum cylinder pressure control and passive load-holding function. This control algorithm is tested on a single-boom crane characterized by overrunning loads. It is designed based on the analysis of the system characteristics, requiring no MIMO controller analysis and design. A non-linear model of a single-boom crane driven by the proposed 2M2P MCC is created in MATLAB/Simulink and experimentally validated. Feedback controllers are designed and verified via simulations to realize position control, minimum cylinder pressure control, and load-holding under standstill command. For a given load and speed profile, the hydraulic system efficiency during pumping and motoring mode is 55-60% and 20-25%, respectively. The system's overall efficiency can be enhanced with electrical regenerative drives, which feeds the generated power from potential energy to the grid or battery and reused in the next working cycle. The experimental results presented in this paper verifies the efficacy of the proposed control algorithm and demonstrates its superior performance in achieving the desired system response under various operating conditions.
Reverse osmosis (RO) is a widely used desalination technology known for its high energy requirements. However, the incorporation of energy recovery devices (ERDs) in RO plants has proven effective in ...reducing specific energy consumption. The booster pump (BP) is an essential component utilized in conjunction with isobaric ERDs. Approximately 5 to 10 % of the capital cost for small to medium-sized RO units is attributed to the BP. The objective of this paper is to investigate the feasibility of implementing a newly designed isobaric ERD called DAC. The study focuses on an RO plant with a capacity of 48 m3/day. The proposed ERD undergoes design, manufacturing, and experimental testing. The major benefit is its ability to utilize the system feed pump as a BP, eliminating the need for a separate BP. This equipment reduction not only lowers the initial cost but also simplifies the system complexity. Furthermore, the system is designed to allow a comparison between the DAC and a pressure exchanger (PX) under the same operating conditions. However, unlike the DAC, the PX becomes unresponsive and does not function when the BP is turned off to allow the system feed pump to take over.
•Introducing a novel isobaric energy recovery device into the reverse osmosis system•Eliminating the requirement for a booster pump results in a reduction in both the initial cost and system complexity.•Conducting a comparative analysis between the DAC and a conventional pressure exchanger•The operation of pressure exchanger is dependent on the presence of a booster pump.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This article presents a dynamic model of the TMM-3M heavy mechanized bridge during the frame lifting stage, which is driven by a hydraulic system, constituting the initial phase of the bridge ...erection process. The model is constructed as a multi-body dynamic system, taking into account the elastic deformation of the rear outriggers, front tires, and front suspension system. The research model integrates a mechanical system controlled by hydraulic cylinders, with pressure being considered as a variable reacting to external loads during the system's operation. Lagrangian equations of the second kind are utilized to establish a system of differential equations describing the oscillations of the system and form the basis for investigating the dynamics of the frame lifting process. The system of differential equations is solved numerically using MATLAB simulation software based on the Runge-Kutta algorithm. The study has revealed laws regarding the displacement and velocity of components within the system, evaluating the stability of the TMM-3M heavy mechanized bridge during operation. This research paves the way for a comprehensive understanding of the working process of the TMM-3M heavy mechanized bridge, aiming for practical improvements to minimize deployment or retrieval time, reduce the number of deployment team members, enhance the automation of the operation process to reduce the workload for operators
The present research concerns the feasibility study of a hydraulic cylinder for high pressures made of composite material and aluminium alloy. The study concerns the design of a hydraulic cylinder, ...for applications on a big excavator (pressure = 300 bar), adopting structural steel, aluminium alloy and finally composite material (carbon fibres and epoxy resin). The design methods adopted are both analytical and numerical. The construction technique hypothesized to make the composite component (cylinder tube) is filament winding. To avoid the damage caused by the sliding of the piston seals on the inside diameter of the cylinder tube, an aluminium tube is provided on which the composite material is wound. A series of experimental tests were carried out on a scale prototype. The results show that the solution created by the composite material and the aluminium alloy has a significantly lower weight compared to the steel solution; the value is about 10.5%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A general dynamic modeling procedure for planar flexible manipulators.•A general procedure for force analysis of planar flexible manipulators.•Rigid body velocities and velocities caused by ...elasticity are represented as twists.•Coupling of dynamics of a manipulator and hydraulic cylinders using bond graph.•An implementation example for a planar flexible knuckle boom crane.
In this paper we present a modeling procedure for a flexible knuckle boom crane, which is actuated by hydraulic cylinders and is modeled as a planar multibody system. We propose a convenient framework where both rigid body velocities and velocities caused by flexible behavior are represented as twists. Such formulation allows for using screw transformations, which leads to systematic derivations. Dynamics of a crane and mass balance of hydraulic cylinders are coupled using the bond graph method. In addition, we present a procedure for the determination of reaction forces in passive joints, which is conveniently given as an extension of the dynamic modeling procedure. Both procedures are presented in a general and systematic manner such that they can be applied for a group of planar flexible manipulators.
We study the dynamics of luffing motion of a crane by numerical simulation and provide the simulation results, as well as determine the reaction forces in passive joints. The simulation results are validated by the ANSYS finite element analysis. The derived model provides a basis for design of luffing cylinders and can potentially be used for studying performance of a crane control system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper presents both an example of the innovation prototype risk assessment and the universal way of conduct in assessing such solutions. For this purpose, the authors proposed a prototype risk ...assessment method based on the assumptions of the SWOT and TOWS analysis and the multi-criteria technical innovation risk assessment method. In the assumptions of the developed method, an account was taken of the conclusions resulting from the prospect theory. A symptom of this action was, e.g., a characterization of the team of experts (working on the prototype) in terms of their individual personality traits and mind (which has not been used so far in practical methods of assessing risk). As a result of the conducted assessment (for an innovative hydraulic cylinder prototype), the innovation prototype risk was determined as low, which was presented both on the map of domination and the map of risk assessment for this prototype. The procedure presented in the paper was planned so as to ensure that, after the prototype moves to the commercialization phase, it will be possible, on the basis of the already made calculations, to apply the full risk assessment dedicated for technical innovations with ease. This gives it a universal nature.
Powered roof support in a longwall operation is designed to maintain a safe working area and allow the immediate roof to fail and collapse behind the support. The powered supports are loaded using ...large hydraulic pumps with non-return and preset-yielding valves. In addition to providing support to the immediate roof in the longwall production area, it also moves the armoured face conveyor and shearer forward as coal mining progresses. The research aimed to analyse the changes in the pressure values in the powered roof support section's hydraulic cylinders in relation to the occurrence of rock mass movements in the roof. The pressure measurements are based on the sensors in the sub-piston space of the powered roof support hydraulic prop located in the steel wall. The results allow a correlation to be developed between the roof movement and the loads generated in the hydraulic cylinders.
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