Thermo Scientific HESI-II Probe, User Manual

Page: 31 / 36

4
Maintenance
Replacing the Needle Insert
Thermo Scientific HESI-II Probe User Guide 21
To support flow rates from 1 to 2000
μ
L/min, Thermo Fisher Scientific provides two needle
inserts for the HESI-II probe. The difference between the two inserts is the size of the metal
needle and supporting ferrule (
Table 3 ).
Replacing the needle insert requires a 3 mm (7/64 in.) hex wrench or ball driver.
Y To replace the needle insert
1. Remove the HESI-II probe from the Ion Max API source (see “Removing the HESI-II
Probe” on page 9 ).
2. Unscrew the fingertight fitting from the sample inlet port (see Figure 16 on page 16 ).
3. Remove the needle insert from the probe as follows (see Figure 20 ):
a. Using a 3 mm (7/64 in.) hex wrench or ball driver, remove the two M4
×
35 mm
length, socket head cap screws.
b. Pull the end cover off of the probe.
c. Unscrew the needle insert, and then pull it out of the probe body.
Figure 20. Exploded view of the HESI-II probe
Table 3. Needle inserts
Description Metal needle Ferrule Flow rate range
32-gauge needle insert,
HESI-II probe 0.004 in. ID
0.009 in. OD
0.4 mm thru-hole 5 to 2000
μ
L/min
34-gauge needle insert,
HESI-II probe 0.003 in. ID
0.007 in. OD
0.2 mm thru-hole 1 to 10
μ
L/min
Metal needle insert
End
cover
Probe body
M4
×
35 mm length
socket head cap
screws (2
×
)