Application guidelines
21
FRCC.PC.002.A5.22
Sound and vibration management
Vibration
Sound
The mounting grommets delivered with the
compressor should always be used. They will
largely attenuate the compressor vibration
transmitted to the base frame. These rubber
grommets have been selected and calculated in
accordance with the vibration frequencies that
are typical for the compressor. For that reason
other grommet types or brands shall not be used.
The base on which the compressor is mounted
should be sufficiently rigid and of adequate mass
to ensure the full effectiveness of the mounting
grommets. The compressor should never be
rigidly mounted to the base frame otherwise
high vibration transmission would occur and
the service life reduced. Suction and discharge
lines must have adequate flexibility in 3 planes.
Eventually vibration absorbers may be required.
Vibration is also transmitted by the refrigerant
gas. Maneurop® NTZ compressors have built-in
mufflers to reduce pulsation. To further reduce
vibration an extra discharge line muffler can be
installed.
Compressors in operation are one of the sources
of sound and vibration in a refrigeration system.
Both phenomena are closely related.
Sound produced by a compressor is transmitted
in every direction by the ambient air, the
mounting feet, the pipework and the refrigerant
in the pipework. The easiest way to reduce
the sound transmitted through ambient air
is to fit an acoustic hood accessory. Because
Maneurop® NTZ compressors are 100% suction
gas cooled and require no external cooling they
can be insulated or enclosed in a sound proofing
material lined compartment.
Sound transmitted by mounting feet, pipework
and refrigerant should be treated the same way
as vibration (see next section).
Compressor
model
Sound power level*
at 50 hz dB(A)
Sound power level*
at 60 Hz dB(A)
Acoustic
hood
code no.
without hood
with hood
without hood
with hood
NTZ048
70
65
73
68
120Z0575
NTZ068
65
60
69
64
NTZ096
82
74
85
77
120Z0576
NTZ108
76
69
80
75
NTZ136
77
71
80
75
NTZ215
86
80
88
81
120Z0577
NTZ271
86
80
88
81
(*) Operating conditions: R404A, Evap. temp.: -31°F, Cond. temp.: 104°F