Hydraulic accumulator - Energy accumulation

Energy saving is the most important topic for the use of Hydraulic accumulators in hydraulic systems. Accumulators allow the use of smaller pumps and therefore, with lower installed power, lower heat dispersion, easier installation and maintenance. In other words, reduced operating costs. In systems where there is a large demand for oil in short times or where there are cycles with very short times, an economic solution can only be reached with Hydraulic accumulators.

As can be seen from the diagram opposite, the three uses have differentiated oil demands. Without Hydraulic accumulators, the flow rate of the pump must conform to the request for greater use, the 3. By using the accumulator, the flow rate of the pump (and consequently the cost of installation and operation) can be substantially reduced. The demand for oil for uses 1 and 2 is lower than the pump capacity. The amount of excess fluid is accumulated. The oil demand of the use 3 is higher than the pump capacity and the extra quantity is supplied by the accumulator. During breaks in the work cycles the Hydraulic accumulator is recharged.

In die-casting machines, for plastic injection molding and blow molding, large quantities of oil are required in a short time during the injection phase. The same need for large quantities of oil in a short time occurs in the rapid closing systems present in the turbines, in power plants, etc. in most cases, such rapid closing systems provide for the control of safety devices, ie during normal work, the oil demand is minimal (only to compensate for drainage losses). Without the Hydraulic accumulator, the pump should continuously pump a large non-pressure flow, so that when the safety devices require it (perhaps once or twice a year), the necessary quantity of oil is immediately available. such solutions would be very uneconomical.

Hydraulic accumulators maintain the closing pressure between two rollers for a long time. Once the closing pressure is reached, the pump can be inserted immediately on other uses. The Hydraulic accumulator maintains the required closing pressure throughout the entire process.

Instead of dissipating kinetic energy, it is stored by an accumulator that can return it as needed. This application is found among other things in the presses where, when the slider is lowered, the oil accumulates in the Hydraulic accumulator and can therefore be reused for the return journey.

Rational machining in pressing and molding operations involves high speeds in the vacuum approach phase and only the actual machining process takes place at lower speeds and at high pressure.
During the vacuum approach phase, both pump 1 (low pressure pump) and pump 2 (high pressure pump) and the Hydraulic accumulator are supplied with flow, all in order to obtain the desired high speed.
As the pressure increases at the end of the approach stroke, the check valve A closes and therefore only the pump 2 supplies reduced flow at high pressure, while the pump 1 recharges the accumulator.