Danfoss Maneurop NTZ048, Отбор и руководство по применению

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RECIPROCATING COMPRESSORS
18
SOUND AND VIBRATION MANAGEMENT
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 72 65 72 65
7755001
NTZ068 71 64 75 68
NTZ096 84 78 84 77
7755002 NTZ108 82 75 82 75
NTZ136 77 71 84 77
NTZ215 84 78 88 81
7755002
NTZ271 84 78 88 81
(*) Operating conditions:
R404A, Evap. temp.: -35°C, Cond. temp.: 40°C, 400 V / 50Hz
Sound produced by a compressor is
transmitted in every direction by the
ambient air, the mounting feet, the
pipework and the refrigerant in the pi-
pework. 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 re-
Sound
Compressors in operation are one of
the sources of sound and vibration in a refrigeration system. Both pheno-
mena are closely related.
quire no external cooling they can be
insulated or enclosed in a sound proo-
fing material lined compartment.
Sound transmitted by mounting feet,
pipework and refrigerant should be
treated the same way as vibration (see
next section).
Vibration
The mounting grommets delivered
with the compressor should always
be used. They will largely attenuate
the compressor vibration transmit-
ted to the base frame. These rubber
grommets have been selected and
calculated in accordance with the vi-
bration 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 trans-
mission would occur and the service
life reduced. Suction and discharge
lines must have adequate flexibility in
3 planes. Eventually vibration absor-
bers may be required.
Vibration is also transmitted by the
refrigerant gas. Maneurop® NTZ com-
pressors have built-in mufflers to re-
duce pulsation. To further reduce vi-
bration an extra discharge line muffler
can be installed.