Danfoss VRJ, Инструкции по применению

Страница: 19 / 24

Application Guidelines
19
AB141686422149en-US0401
Sound and vibration management
Speed bypass
Gas pulsation
Mechanical vibrations
If vibrations still occur at some typical
frequencies, a speed bypass function is available
within the VRJ. This function allows avoiding some frequency ranges and avoiding vibrations
to occur. Refer to “Danfoss VRJ Installation and
Operation instructions” for setting details.
The VRJ scroll compressor has been designed
and tested to ensure that gas pulsation has been
optimised for the most commonly encountered
air conditioning pressure ratio. On heat pump
installations and other installations where the
pressure ratio lies beyond the typical range,
testing should be conducted under all expected conditions and operating configurations to
ensure that minimum gas pulsation is present. If
an unacceptable level is identified, a discharge
muffler with the appropriate resonant volume
and mass should be installed. This information
can be obtained from the component
manufacturer.
Vibration isolation constitutes the primary
method for controlling structural vibration. VRJ
scroll compressors are designed to produce
minimal vibration during operations. The use
of rubber isolators on the compressor base
plate is very effective in reducing vibration
being transmitted from the compressor to
the unit. Rubber grommets are supplied with
all Danfoss compressors. Once the supplied
rubber grommets have been properly mounted,
vibrations transmitted from the compressor base
plate to the unit are held to a strict minimum.
In addition, it is extremely important that the
frame supporting the mounted compressor be
of sufficient mass and stiffness to help dampen
any residual vibration potentially transmitted to
the frame. The tubing should be designed so as to both reduce the transmission of vibrations to
other structures and withstand vibration without
incurring any damage. Tubing should also be
designed for three-dimensional flexibility.
During unit development, the complete
compressor speed range should be covered, in
order to define if abnormal vibrations occur or
not. As ultimate solution, speed bypass can be
applied.
For more information on piping design, please
see the section entitled “Essential piping design
considerations”.