Emerson Vilter VSG128, Installation, Operation And Service Manual

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Section 3 • Installation
HPLD Single Screw Compressor • Installation, Operation and Service Manual • Emerson • 35391HP
Testing System For Leaks
CAUTION
Do not hydro test compressor unit. Failure to comply
may result in damage to equipment.
CAUTION
The compressor unit along with other system units
contain many components with various pressure
ratings. Pressure relief protection provided considers
the design pressure of a system components.
Before replacing a pressure relief valve with a relief
valve having a higher pressure setting, all system
components must be evaluated for acceptability.
Vilter
TM
equipment is tested for leaks at the factory. One
of the most important steps in putting the system into
operation is field testing for leaks. This must be done to
assure a tight system that will operate without any ap-
preciable loss of gas.
First, if test pressures exceed the settings of the system,
relief valves or safety devices, they must be removed and
the connection plugged during the test. Secondly, all
valves should be opened except those leading to the at-
mosphere. Then, open all solenoids and pressure regula-
tors by the manual lifting stems. All bypass arrangements
must also be opened.
Hydrocarbon Systems
“Oil pumped” dry nitrogen, or anhydrous CO
2
in this order
of preference may be used to raise the pressure to the
proper level for testing.
When the proper pressure is attained, test for leaks with a
mixture of four parts water to one part liquid soap, with a
few drops of glycerin added. After all leaks are found and
marked, relieve the system pressure and repair the leaks.
Never attempt to repair soldered or welded joints while
the system is under pressure. Soldered joints should be
opened and re soldered.
Do not simply add more solder to the leaking joint. After
all the joints have been repaired and the system is con-
sidered “tight”.
Remove the drum and bring the pressure to the recom-
mended test level with oil pumped dry nitrogen or CO
2
.
Then check the entire system again for leaks, using a
halide torch or electronic leak detector. Be sure to check
all flanged, welded, screwed and soldered joints, all gas -
keted joints, and all parting lines on castings. If any leaks
are found, they must be repaired and rechecked before
the system can be considered tight again, remembering
that no repair should be made to welded or soldered joins
while the system is under pressure.
CO
2
Systems
A CO
2
system will tend to be more prone to leaks due
to the higher working pressures, and therefore its leak
detection should become a regular maintenance proce-
dure. For a charge size of above 661 lbs, for example, the
recommendation would be to perform the leak detection
procedure about 4 times a year.
An oil stain will be a visual indicator of a CO
2
leak, but there
are also leak detection sprays available in the market (such
as Weicon´s or Bulleye´s), infrared hand held leak detec-
tors (such as D-TEK CO2), and ultrasonic leak detectors
of several brands
1
.
Oil For Single Screw Compressors
Due to the need for adequate lubrication, Vilter
TM
rec-
ommends only the use of Vilter
TM
lubricants, designed
specifically for Vilter
TM
compressors. With the extensive
research that has been performed, we are able to offer
specific lubricating oils. Use of oil not specified or supplied
by Vilter
TM
will void the compressor warranty.
1
Information taken from Commercial CO
2
Refrigera-
tion Systems Guide for Subcritical and Transcritical CO
2
Ap-
plications, by Emerson