Waters 2707 Operator's Manual page 60

Pairing air needles with titer plates or vials
Consider the following dimensions when choosing an air needle:
• Height of the titer plate, in mm (Ht)
• Well depth, in mm (Dw)
• Thickness of capmat or seal, in mm
(Cd)
• Set needle height, in mm (Nh)
• Distance of the air needle point
through the capmat or seal in mm,
minimum 2 mm (Ac)
Ht – Dw must be between 2 and 6 mm,
at which value you can calculate the
protrusion length of the sample
needle—the distance between the point
of the sample needle and the point of
the air needle—as Ht – Cd – Nh – Ac.
On the basis of protrusion length, choose the most suitable air needle.
Air needle type
50 mm, yellow
56 mm, red
62 mm, white
(standard needle)
68 mm, blue
74 mm, green
80 mm, black
3-10 Maintaining the Autosampler
H
Protrusion length from
34
28
22
16
10
4
C
A
D
w
t
N
Protrusion length to
40
34
28
22
16
10
d
c
h