2.6 Antivibration Bolt-Down Requirement
01-999021-00 A0100
Installation Planning Guide
17
400/54 magnet without the SMS
autosampler: The antivibration
system for this magnet consists of
dampening equipment integrated
into the magnet legs, as illustrated in
2.6 Antivibration Bolt-Down Requirement
For the 400/54 and all long-hold magnets with an antivibration system, the magnet legs
must be bolted to the floor. The antivibration system used with these magnets incorporates
the dampening mechanism as an integral part of the magnet leg. Although in normal
operation these antivibration legs are stable, for maximum safety Varian requires that they
be anchored to the floor after installation. Anchoring to a floor is a standard procedure for
many types of equipment, and Varian expects that the customer’s plant or maintenance
personnel can usually accomplish it. The anchoring requires four 2.5-inch embedments for
each leg, anchored using 0.5-inch bolts. Details are provided in the manual MERCURY-VX
Accessory Installation; this note is provided for information purposes only.
2.7 Floor Vibration Requirements
The floor must be sufficiently rigid to reduce the vibration from adjacent dynamic loads to
a negligible level, defined as no single peak vibration greater than 20
µ
g acceleration, from
0 to 100 Hz. For sites exceeding this specification, antivibration equipment is necessary.
Sites with vibrations below 5 Hz are not recommended for the installation of any NMR
spectrometer. Use of the tire-type antivibration systems are not generally recommended at
sites with vibrations below 20 Hz or any site with large vibrations in the horizontal
directions. Ground floor or basement sites are generally preferred because the natural
resonant frequencies of most building structures are typically low frequencies and
horizontal in direction.
Measurement is made with an Ono Sokki Model CF 200 field FFT analyzer using 16 rms
time averages and a seismic accelerometer with 10 V/g sensitivity.
R = 21.125 in
3 leg pads on floor
9 x 9 in (22.9 x 22.9 cm)
Magnets:
Figure 4. Magnet Leg Antivibration
System Leg Placement and Sizes
400/54 and all LH
(53.7 cm)