www.sitspa.com
TRASCO
®
- User and Maintenance Manual
114.02 - Rev. 2 - 2
nd
March 2020
Approved by: SIT S.p.A.
28
5.5 Hub machining in ATEX environment
5.6 Elastic spider check
The machining of the bore, the seat of the keyway and the threaded bore for the fixing screw must follow the instructions provided in
the UNI-ISO 2768 standard. Any other machining on couplings to be used in hazardous zones must obtain the express consent of SIT.
The customer must provide SIT with a technical drawing showing the machining to be carried out. It is the responsibility of SIT to evaluate
and approve it.
The elastic spider must undergo periodic checks for wear.
The first check must be made after 2000 hours of operation or after 3 months from the start of use.
The next check should be made after 4000 hours or 12 months, provided that the first inspection did not show excessive wear values that
led to replacement of the elastic spider.
The check is performed using a feeler gauge to assess the wear of each element of the spider.
If the measured value (Z value) is higher than that indicated in the Z VALUE FOR CHECKING SPIDER WEAR, it is recommended to replace
the spider with an equivalent one.
SIZE
QUOTE Z
[mm]
19/24
3
24/32
3
28/38
3
38/45
3
42/55
4
48/60
4
55/70
5
65/75
5
SIZE
QUOTE Z
[mm]
75/90
6
90/100
8
100/110
9
110/125
9
125/145
10
140/160
12
160/185
14
180/200
14
Table 5.4 - Z value for checking spider wear
Z
5.4.2 Compact marking
Where the size of the coupling does not allow complete marking, the Directive allows a reduced version which refers to this manual for
its comprehension.
The letter
X
refers to this manual which includes a summary table of the temperature class and the resulting maximum permissible
ambient temperature that must be at least 20 K less, in accordance with the elastic spider’s ability to resist.
I M2 / II 2GD Ex h X
