Ten serwis zostanie wyłączony 2025-02-11.
Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 2

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
Working and moving in confined, limited and narrow spaces, specific to underground mining activities, also requires the use of hydraulically operated equipment, capable of developing large forces, with small dimensions. An example of such equipment includes pumping units comprising low-pressure electric pumps and oscillating hydraulic pressure intensifiers. They use low pressure in the primary side of the intensifier and generate high pressure in the secondary side of the intensifier. Such pumping units are usually used to achieve and maintain high pressure, either in the volumes of closed spaces (in strength tests on pipes and tanks) or at the end of the active stroke of hydraulic cylinders (in hydraulic presses). On an experimental laboratory bench, which comprises a test cylinder, powered by a pumping unit, equipped with an oscillating hydraulic pressure intensifier, and a load cylinder, powered by another pumping unit, with the possibility of load control, the authors show that: the application range of these pumping units can be extended in the third direction, too, useful for underground mining activities, namely for drive of hydraulic cylinders with low gauge / displacement speeds and constant high load (high working pressure) over the entire working stroke length; the uniformity of displacement of these cylinders, with load throughout the stroke length, which are powered and driven with such pumping units, is slightly affected by the pulsating mode of operation of the hydraulic pressure intensifier. A set of experimental measurement results is presented for a constant value of the load over the entire displacement stroke of the test cylinder.
EN
Oscillating hydraulic pressure intensifiers, of the minibooster type, are supplied at the inlet, in the primary, by low-pressure pumps and provide, at the outlet, in the secondary, high pressure to the hydraulic consumers (linear or rotary hydraulic motors under load). The pressure increase in the secondary, proportional to the amplification factor of the intensifier occurs at a much lower flow rate than the supply flow rate, and thus the two hydraulic parameters (pressure and flow rate) at the outlet of the intensifier are affected by oscillations. Because of this, the miniboosters are designed for static applications, which require low displacements of hydraulic motors. The authors aimed to expand the field of use of miniboosters by reducing the flow rate and pressure pulses with the help of hydro-pneumatic accumulators mounted on the primary and secondary of the intensifiers. If these pulsations can be mitigated, then low-pressure pump units of small dimensions, equipped with miniboosters, can be used in dynamic mining-specific applications, in complete safety, such as, for example, those involving relatively uniform displacement, under load, of some hydraulic jacks. A numerical simulation model developed in Simcenter Amesim highlights the effect of using hydro-pneumatic accumulators on the mitigation of flow rate and pressure pulsations of the oscillating hydraulic intensifiers. Numerical simulations performed with and without hydro-pneumatic accumulators mounted on the primary and secondary of the intensifier highlight the following aspects: • hydro-pneumatic accumulators can be used successfully for the partial damping of flow rate and pressure pulses, but they must be dimensioned for each specific application and work optimally for a relatively narrow pressure range; • using hydro-pneumatic accumulators can sufficiently improve the uniformity of displacement and the velocity of displacement of a hydraulic cylinder, so that it can be used in less demanding dynamic applications, as well.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.