Working principle & Sketch of the Hydraulic Accumulator

 Hydraulic Accumulator:-


The accumulator means a device that can store something. The hydraulic accumulator is a device that can store water energy temporarily and make available this energy when it's required. In the case of hydraulic machines such as lifts and cranes, the liquid under pressure is required during the upward motion of lifts or when the load is being lifted by a crane. These machines do not need any energy otherwise when a lift is moving down or load is being lowered by the crane. Therefore, an accumulator can store energy when the machines do not require energy and supply the same when machines require energy. The function of any hydraulic accumulator is analogous to that of the flywheel of an IC engine or electric storage battery. Besides storages of energy hydraulic an accumulator helps to dampen pressure surges and shocks in the hydraulic system so as to function as a pressure regulator.

Simple Hydraulic Accumulator:-

Its consists of a vertical cylinder which consists a sliding ram. A load is placed on the top of the ram to create pressure in the cylinder chamber. One side of the cylinder has an inlet, connected to the pump and another side of the cylinder has an outlet., connected to the machines. The liquid at high pressure is supplied by the pump and liquid enters the cylinder chamber to raise the ram with the load. When the hydraulic machine is Idle, the liquid can be accumulated in the cylinder chamber till the ram reaches its uppermost portion in the cylinder chamber. The cylinder is now completely filled up with the liquid at this point and the maximum amount of pressure energy at a later stage can be supplied to the hydraulic machine as and when is required during its working stroke. The maximum amount of energy that can be stored in the hydraulic accumulator is called the capacity of the accumulator and it is equal to the work done in lifting the ram with weight.

Hence,.....          Capacity of Accumulator = weight x height of lift (L)

                                                        weight = pressure(P) x area of cross-section of ram (A)

                                                                    = P x A

such as Capacity of Accumuulator = P x A x L


 2.  Differential Hydraulic Accumulator:- It consists of a fixed vertical ram that has the central liquid passage of small diameter. The ram surrounded by a closely fitting brass or silver at the lower end. the bush is surrounded by an inverted sliding cylinder which has a circular projected collar at its bottom end. The weight is placed on the collar. The passages for the liquid to enter leave the sliding cylinder provided in the fixed ram. The advantage of the differential accumulator is that can store liquid at high pressure by a comparatively small load on the ram.



The liquid from the pump with pressure enters the cylinder through the central vertical passage provided in the fixed ram. The entring liquid in the cylinder causes the loaded sliding cylinder t move upward by exerting pressure P on the annular area of the sliding cylinder which equals to the cross-section area of the brass sleeve on the ram, thereby storing the hydraulic energy. When the liquid is drawn by the machine from the accumulator, the liquid sleeve the cylinder from the same central passage provided in the fixed ram.

The capacity of an acculumator is equal to the work done in lifting the siliding cylinder with weights on its collar.

Capacity of accumulator = weight(W) x lift(L)

                                       = W x L

But, weight(W) = pressure(P) x cross-section area of brass lining(A)

                          = P x A

                      A = π / 4 x ( D2 – d2)                           where, D= external dia. of brushing lining

                                                                                                d= dia. of fixed ram

Capacity of the Accumulator = P x A x L

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