Revista HIDRAULICA | HIDRAULICA Magazine

ISSN 2343–7707 ; ISSN-L 1453-7303

HIDRAULICA Magazine No. 4 / 2014


Hidraulica no.4/2014


EDITORIAL

HALF FULL
Petrin DRUMEA

Manager of Publication

About hydraulics in our country we have spoken often, often stated our opinion, and pointed out the problems of this activity field, but very rarely and quite a bit have emphasized also the good stuff. In this editorial I will try to highlight the half full glass, avoiding to criticize many things that bother me. .…. (read more)


DEVELOPMENT OF A TEST BENCH FOR ANALYSIS  OF THE SUPPLY PRESSURE VARIATION IN HYDRAULIC SYSTEMS
Authors: R.M. Castro, J.M. Neto, Y.M. Morona, K. Machado, A. S. Rocha

Hydraulic systems have gained widespread use and applicability to the industrial manufacturing process. Although the hydraulic technology is old, there are many modern applications such as presses, mechanical excavators, backhoes, loaders, forklifts and cranes. However, studies show that the stability of the supply pressure is a determinant for gain efficient of any hydraulic equipment. This study aimed to analyze the characteristics of the variation in supply pressure in a hydraulic system under different conditions of operation, through a test bench. Were first showed constructive and operating characteristics of the major components analyzed, these being…. (read more)


EXPERIMENTAL RESEARCH ON VISCOUS FLUID FLOW  THROUGH SEALING LABYRINTHS
Authors: Sanda BUDEA, Stefan SIMIONESCU, Mircea D. CAZACU

This article refers to the results of experimental research regarding the viscous fluid flow through sealing labyrinths of turbo machines. This labyrinths can be met both at the interstice between rotor and housing, and in the zone of the interstice of the balancing disc.  Within the experimental researches, fluid flows through the labyrinths at different Reynolds numbers were visualized, pressure variations along the length of the labyrinth and increase in rotation speed of the mobile ring were analysed. The experimental results have largely overlapped the numerical ones, confirming that…. (read more)


MECHATRONIC DRIVE SYSTEM FOR CLEANING MACHINE OF PHOTOVOLTAIC PANELS
Authors: Radu RADOI, Marian BLEJAN, Ioana ILIE

The efficiency of the photovoltaic panels depend on the cleanliness of the reception surface of solar energy. As in time on this are deposited all kinds of impurities, the productive efficiency can drop even up to 50 %. It is necessary from this cause their regular cleaning. The paper presents  the structure of the cleaning machine, hydraulic scheme and the mechatronic system based on…. (read more)


INFLUENCE OF NITRIDING THERMOCHEMICAL TREATMENTS UPON CAVITATION EROSION RESISTANCE OF DUPLEX X2CrNiMoN22-5-3 STAINLESS STEELS
Authors: Lavinia Madalina MICU, Dorin BORDEASU,  Ilare BORDEASU,  Mihaela POPESCU,  Octavian Victor OANCA, Sebastian Titus DUMA

The duplex stainless steels X2CrNiMoN22-5-3 is widely used today, in chemical industry, in shipbuilding industry, in construction industry, in food industry etc., because it has good resistance to intercrystalline corrosion and, better physical and mechanical properties then austenitic steels. The mechanical properties of those steels, depends very much on their chemical composition and on the applied treatment. This paper presents the effect and the advantage of applying nitrogen during the nitriding thermochemical process upon the cavitation erosion resistance of the stainless steels X2CrNiMoN22-5-3, in comparison with the quenching heat treatment and low tempering. The researches were undertaken at Timisoara “Politehnica” University in the Cavitation Laboratory, using… (read more)


TRIBOLOGY PERSPECTIVE ON SEATBELT PRETENSIONING SYSTEM
Tribology perspective on seatbelt pretensioning mechanism
Author: Paul IMRE

This paper presents the factors and forces involved in the concept propulsion unit of a seatbelt pretensioning mechanism. The function and role of seatbelt pretensioning will be presented as an introduction, but the paper will focus on the propulsion from a tribology perspective focusing on the experiments and simulations performed to determine…. (read more)


OPTIMIZING THE ENERGY CONSUMPTION OF AN INDUSTRIAL WATER-SUPPLY PUMP SYSTEM BY ENSURING AN OPTIMAL FLOW RATE
Authors: Gencho POPOV, Boris KOSTOV, Miglena HRISTOVA, Donka IVANOVA, Anka KRUSTEVA

This work presents theoretical research about the possibilities for achieving at the same time a system’s optimal flow and maximum energy efficiency, by using the frequency method of flow rate regulation, with a number of pumps working in parallel. Features, concerning the change of the specific energy consumption, used for the ensuring of different total flow rates in the system, are also indicated. An interesting conclusion is the fact that…. (read more)


TWO OPERATING MODES ELECTRO-HYDRAULIC SERVO VALVE
Authors: Teodor Costinel POPESCU, Alina Iolanda POPESCU

This material refers to a new type of hydraulic equipment for proportional distribution of the working fluid, electro-hydraulic servo valve type, which can work also in high adjustable frequency, through remote electronic control. The equipment, which can be used in precision hydraulic systems, particularly those with automatic operating mode, is patent pending. It offers several advantages over conventional solutions.… (read more)


EXPERIMENTAL RESEARCH ON HIGH EFFICIENCY SOLAR AIR HEATING COLLECTORS
Authors: Adrian CIOCANEA, Dorin Laurentiu BURETEA

The paper presents a comparison between two solar air heating collectors: a single passage and a through-pass one with the same geometry, cross section and materials used. Both collectors were exposed to the sun in the same conditions of irradiation, angle of inclination, wind speed and internal air flow rate. Thermal transducers were mounted in the same position for both collectors in order to obtain the inlet temperature spectrum. According to the experimental data… (read more)

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