MTS Series 505 SilentFlo Hydraulic Power Unit Model 505-180 - Manual (Page 44)

Model 505.60 - 505.180 SilentFlo™ HPU 44
General Safety Practices: Hydraulic Power Units and
Safety
Know the causes of
unexpected actuator
motions
The high force and velocity capabilities of MTS actuators can be destructive and
dangerous (especially if actuator motion is unexpected). The most likely causes
of unexpected actuator response are operator error and equipment failure due to
damage or abuse (such as broken, cut, or crushed cables and hoses; shorted wires;
overstressed feedback devices; and damaged components within the servocontrol
loop). Eliminate any condition that could cause unexpected actuator motion.
Do not use RF
transmitters
Keep radio frequency (RF) transmitters away from the workstation computers,
remote terminals, and electronics consoles. Intense RF fields can cause erratic
operation of the more sensitive circuits in the system.
Know compressed gas
hazards
Some environmental chambers use liquid nitrogen or some inert gas to achieve a
required test atmosphere. Typically these gasses are supplied in pressurized
tanks.
Observe the following safety practices when you work with high-pressure air or
gases:
• When you charge an accumulator, follow all the charging instructions
provided in the appropriate product information manuals. When precharging
accumulators, properly identify the type of gas to be used and the type of
accumulator to be precharged.
• Use only dry-pumped nitrogen to precharge nitrogen-charged accumulators.
(Dry-pumped nitrogen can also be labeled “oil pumped” or “dry water
pumped.”) Do not use compressed air or oxygen for precharging: the
temperature increase caused by rapid gas compression can result in highly
explosive conditions when hydraulic fluid is in the presence of oxygen or
compressed air.
• Always follow the recommended bleeding procedures before you remove or
disassemble components that contain pressurized gas. When you bleed a gas
or remove a fitting, hose, or component that contains a gas, remember that
many gases cannot support life. Therefore, as the ratio of released gas to
oxygen increases, so does the potential for suffocation.
• Wear appropriate safety devices to protect your hearing. Escaping air or gas
can create a noise level that can damage your hearing.
• Ensure that all pressurized air or gas is bled out of a pneumatic or gas-
charged device before you start to disassemble it. A thorough understanding
of the assembly and its pressurized areas is necessary before you undertake
any maintenance. Refer to the appropriate product information for the
correct bleeding procedure.
It may not be obvious or intuitive which bolts or fittings are used to restrain
a pressurized area. On some assemblies, you must remove a cover plate to
gain access to the structural bolts. Sometimes, to protect you from a rapid
release of trapped gases, a small port is exposed when you remove this
cover plate. Exposing this port ensures that the gas precharge is fully bled
before disassembly. However, this is not the recommended procedure for
bleeding a pneumatic or gas-charged device, because it can expose you to
the dangers of escaping compressed gas and particulates that are expelled
from the chamber or around the seals. Do not assume that cover plates and
ports are installed in all the critical locations.