Page 44 - 《橡塑技术与装备》英文版2025年12月

HINA R&P TECHNOLOGY AND EQUIPMENT

as it is compressed. The volume of a certain amount of gas When charging the accumulator with nitrogen, it can
is roughly inversely proportional to its pressure, which is the be done offline separately or on-site without dismantling the
basic principle of an accumulator. equipment. The following method and steps for charging the
accumulator with nitrogen are exemplified by online charging.
During the charging process, use the accompanying FPU-
1 charging and testing device. The specific operation is as
follows (see Figure 7):
(1) Check the nitrogen cylinder, accessories, and warning
labels for completeness to ensure the safety and effectiveness
of nitrogen filling. If they do not meet the requirements, they
should be properly disposed of.
(2) Disconnect the power supply of the hydraulic system,
1—Gas filling screw;2—Diaphragm; 3—Valve plate; 4—Shell;
5—Liquid connection port and keep the hydraulic system in a stopped state.
Figure 6 Schematic diagram of diaphragm accumulator (3) Open the pressure relief hand valve of the hydraulic
structure system and observe the pressure gauge on the hydraulic system
until the system pressure drops to 0 MPa. At this point, all the
Before use, the gas inside the accumulator is usually
oil in the accumulator flows back to the oil tank.
precharged to a precharge pressure P0, at which the volume V0
(4) Open the top cover of the accumulator, connect the
of the gas corresponds to the capacity of the accumulator.
inflation and testing device to the accumulator, connect vone
When the pressure of the hydraulic oil is lower than
end of the nitrogen hose to the connection port (at C) and the
P0, it cannot enter the accumulator, and the accumulator
other end to the nitrogen cylinder (not required for pressure
does not function at this time. Only when the pressure of the measurement).
hydraulic oil is higher than the gas pressure P0 can it enter the
(5) Rotate the handle of the FPU-1 inflation and detection
accumulator. As the pressure oil enters, the gas is compressed,
device to its maximum position (rotate counterclockwise to the
and the pressure continues to rise. Therefore, in order for
maximum), and close the deflation valve (at position B).
the hydraulic oil to continuously enter the accumulator, its
(6) Install the nitrogen pressure regulating valve onto the
pressure also needs to rise accordingly. When the pressure
nitrogen cylinder, connect the nitrogen hose to the pressure
of the hydraulic oil stops rising, it can no longer enter the
regulating valve, and connect the other end to the check valve
accumulator.
port (at C) of the inflation and testing device.
The pressure of the gas and hydraulic oil together
(7) Rotate the handle of the accumulator's inflation
constitutes the stored energy. When the port pressure drops, the
and testing device counterclockwise. When you hear the
gas will push the hydraulic oil out of the accumulator. Once sound of gas escaping, observe the pressure gauge on the
the hydraulic oil is completely expelled, the gas pressure will
tool (this pressure represents the nitrogen pressure inside the
decrease to P0.
accumulator). Based on the value displayed on the pressure
Due to limitations in the pressure resistance and safety of gauge, determine whether inflation is necessary. After making
the shell, each accumulator has a maximum allowable pressure
the determination, rotate the handle of the inflation and testing
limit. Once the shell ruptures, the accumulator may explode.
device clockwise again to tighten the inflation screw on the
To avoid potential combustion risks, nitrogen is usually used as
accumulator.
the working gas in accumulators. During the inflation process,
(8) Slowly open the handle on the nitrogen cylinder,
it is necessary to strictly follow the product instructions.
observe the pressure gauge on the inflation and detection
4.3 Method for charging nitrogen into device (note that the pressure inside the nitrogen cylinder must
accumulator be higher than the inflation pressure), adjust its outlet pressure

·38· Vol.51，No.12