Danfoss Performer SM Series, Выбор и руководство по применению

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Hp
>13 ft/s
0.5%
max. 13 ft
max. 13 ft
0.5%
u-trap
>13 ft/s
evaporator
lp
25 to 40 ft/s
Hp
lp
condenser
23
Proper piping practices should be
employed to ensure adequate oil
return, even under minimum load
conditions, with special consideration
given to the size and slope of the
tubing coming from the evaporator.
Tubing returns from the evaporator
should be designed so as not to trap oil
and also to prevent oil and refrigerant
migration back to the compressor
during off-cycles.
If the evaporator is situated above
the compressor, as is often the case
in split or remote condenser systems,
a pump-down cycle is strongly
recommended. Without a pump-
down cycle, the suction line must
have a loop at the evaporator outlet to
prevent refrigerant from draining into
the compressor during off-cycles.
If the evaporator is situated below the
compressor, the suction riser must
be trapped so as to prevent liquid
refrigerant from collecting at the
thermal expansion valve bulb location
(see fig. 1). When the condenser is above the
compressor, a suitably sized U-shaped
trap close to the compressor is
necessary to prevent oil leaving the
compressor from draining back to
the discharge side of the compressor
during off cycle. The upper loop
also helps avoid condensed liquid
refrigerant from draining back to the
compressor when stopped (see fig. 2).
Piping should be designed with
adequate three-dimensional flexibility.
It should not be in contact with the
surrounding structure unless a proper
tubing mount has been installed. The
tubing mount is necessary to avoid
excess vibration, which can in time
result in connection or tube failure due
to fatigue or wear from abrasion. Aside
from tubing and connection damage,
excess vibration may be transmitted to
the surrounding structure, generating
an unacceptable noise level. (For more
information on noise and vibration, see
the section on: "Sound and vibration
management" p.27).
sYsteM design RecoMMendations
fig 1 fig 2
The SY/SZ240 to SY/SZ380 incorporate
an internal relief valve set to open
between the internal high and low
pressure sides of the compressor when
the pressure differential between
the discharge and suction pressures
surpasses 450 to 550 psi.
This safety feature prevents the
compressor
from developing
dangerously high pressures should
the high pressure cutout fail to shut
down the compressor for any reason.
Hp
lp
Relief valve
internal pressure
relief valve
essential piping design
considerations