Lull 1044C-54 Series II Service Manual - Manual (Page 357)

Axles and Brakes
31200079 9-13
Accumulator
General
The accumulator is a 3000 psi piston-type accumulator. It has a oil volume
of 116 cubic inches and gas volume of 126 cubic inches, with a bore size
of four inches.
The pneumatic accumulator is operated by compressed gas. Gas and
hydraulic oil occupy the same container. When oil pressure rises, incoming
oil compresses the gas. When oil pressure drops, the gas expands, forcing
oil out. The gas is separated from the oil by a “free floating” piston (see
Fig. 9-3). This prevents mixing of gas and oil and keeps gas out of the
hydraulic system. The piston (Item 4) fits into a smooth bore and uses
seals (Item 6) to separate gas (Item 3) from oil (Item 5). O-rings (Item 2) in
the end caps prevent leakage of gas/oil.
The accumulator must be “pre-charged” with gas before use in a system.
This is done by filling the gas chamber with dry nitrogen to a pressure of
400 psi. The gas valve (Item 1) is used for pre-charging and testing the
accumulator.
Fig. 9-3: Accumulator
2
# Description
1 Gas Valve
2 End Cap O-Rings
3 Gas Chamber
# Description
4 “Free-Floating” Piston
5 Oil Chamber
6 Piston Seals
K
111
7
6
1
3
4
5
To Hydraulic System
2