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1. HYDRAULICS
ACCUMULATOR
(PENUMPUK
HIDROLIK)

3. WHAT`S AN ACCUMULATOR?
ACCUMULATOR
• A DEVICE IN WHICH POTENTIAL ENERGY IS
STORED IN THE FORM OF COMPRESSED GAS OR
SPRING OR BY A RAISED WEGHT
ACCUMULATOR
• Accumulator is a pressure vessel for storing
hydraulic pressure in it utilizing compressible and
decompressible nature of nitrogen gas. So, it can
be said that the accumulator has a similar function
to the rechargeable electrical battery.

4. DIFFERENT TYPES OF ACCUMULATOR:
1. Shell
2. Bladder
3. Gas Valve Core
4. Bladder Stem Lock Nut
5. Valve Cap
6. Name Plate
7. Fluid Port
8. Anti-extrusion Ring
9. Spacer Ring
10. Fluid Port Lock Nut
11. Fluid Vent Screw
12. Seal Ring
13. Gas Port Adapter
14. Gas Port Lock Nut

5. BLADDER
ACCUMULATOR
COMMONLY USED
HYDRO PNEUMATIC
ACCUMULATOR
BLADDER IS FILLED
WITH NITROGEN
FITTED IN WELDED OR
FORGED STEEL
PRESSURE VESSEL
BLADDER IS MADE OF
ELASTIC
MATERIAL(RUBBER)
PRE-CHARGED
PRESSURE CAN BE
ADAPTED BY GAS
VALVE ON TOP OF
BLADDER

6. ADVANTAGE
• HIGHEST EFFICIENCY WITH 97 PERCENT ENERGY RETAINMENT
DISADVANTAGE
• NITROGEN WILL PERMEATE THE FOAM BLADDER MATERIAL OVER
TIME AND NEED TO BE PERIODICALLY RECHARGED

7. B) DIAPHRAGM ACCUMULATOR

8. Advantages:
-Diaphragm accumulators have most of the
advantages of bladder-type units
- but can handle gas compression ratios of up to
8:1.
Disadvantages:
-they are limited to smaller volumes
-their performance can sometimes be affected by
gas permeating across the diaphragm.
- Leakage problem also occur in this type of
accumulator

9. PISTON
ACCUMULATOR
Advantage: Virtually no nitrogen escapes so they will not
have to be recharged.
Disadvantage: A bit heavier, and less efficient than the
bladder mod, they are more susceptible to fluid
contamination. Lower response time than the bladder
and diaphragm.

10. M E TA L B E L LO W ACC U M U L ATO R
ADVATAGES
-long stroke relative solid height, which gives maximum
storage volume for a given container size.
-Metal bellow type include exceptionally low spring
allowing the gas charge to do all the work with little
change in pressure from full to empty
-It provides exceptionally high level accumulator
performance. It can be produced with broad spectrum
alloys resulting broad range of fluid compatibility.
Disadvantages:
-Response time is more
-high cost

11. HYDRAULIC
ACCUMULATORS
APPLICATION
W H E R E A R E A C C U M U L ATO R S U S E D ?

12. EMERGENCY AND SAFETY
• An accumulator which is kept constantly under pressure is valuable in the event of an
electrical power failure as it can provide the flow and pressure necessary to perform an
additional function or complete a machine cycle.
Shock or pulsation dampening
• An accumulator can be used to cushion the pressure spike
from sudden valve closure, the pulsation from pumps or the
load reaction from sudden movement of parts connected to
hydraulic actuators.

13. ENERGY CONSERVATION
• An accumulator can be used to supplement a pump during peak demand thereby
reducing the size of the pump and motor required. The accumulator is charged during
low demand segments of the pump cycle time and then discharges during the high
demand portions of the circuit.
Noise reduction
• An accumulator is effective at reducing hydraulic system
noise caused by relief valves, pump pulsations, system shock
and other circuit generated noises.

14. LEAKAGE COMPENSATION
• An accumulator can be used to maintain pressure and make-up for fluid lost due to
internal leakage of system components including cylinders and valves.
Thermal expansion
• An accumulator can absorb the pressure differences caused
by temperature variations in a closed hydraulic system.

15. IMPROVED RESPONSE TIMES
• An accumulator (bladder type) has virtually instantaneous response time that can
provide fluid very quickly to fast-acting valves such as servos and proportionals to
improve their effectiveness.