9. Referring to the following screw tightening rotation sequence, securely tighten the three
Allen screws (3) that connect the valve cap (1) to the valve plunger body (13). One at a
time, tighten each screw to first torque. Then continue with the next torque value until the
final value is reached.
a. Finger tighten
b. 20 inch-pounds (2.3 Nm)
c. 40 inch-pounds (4.5 Nm)
d. 60 inch-pounds (6.8 Nm)
10.Tighten the three Allen screws (16) that secure the plunger valve body (13) to the cylinder
base (14) to approximately 30 to 40 inch-pounds (3.4 to 4.5 Nm).
BE CERTAIN ALL ALLEN SCREWS ARE SECURELY TIGHTENED. DO NOT
OVERTIGHTEN.
4.4.3
Model 20 Valve Specifications
Internal loop sample size:
2 μl standard. (Other sizes are available on special request.)
External loop sample size:
170 μl standard. (Other sizes are available on special request.)
Sample filter:
5 μm recommended (not furnished with valve).
Maximum operating temperature:
122°C (250°F) standard
Maximum sample pressure:
1380 kPa (200 psi) gage instrument air standard.
10350 kPa (1500 psi) gage with 2 80 550 kPa (80psi) gage air signals. Higher
operating pressure available on special request.
Minimum sample pressure:
34.5 kPa (5 psig)
Maximum leak rate between ports:
Less than 1 μl per minute between ports.
Material in contact with sample:
316 stainless steel and Teflon, standard. Other materials are available on special
request.
Connection size and type:
1.6 mm (
1
/
16
") O. D. tubing, with Swagelok® fittings
Actuating air:
345 kPa to 550 kPa (50 to 80 psig) instrument air standard. 550 kPa (80 psig)
maximum. Helium or nitrogen may be substituted for air.
Total switching time:
150 ms (total time from initiation of command signal to completion of change in
valve state)
Body size:
70 mm (2
3
/
4
") diameter by 70 mm (2
3
/
4
") height
Mounting:
Clamp type
Other:
A carrier purge (helium, hydrogen, or nitrogen) may be used (an external low-
pressure gas supply is required).
Valves
4.4 Model 20 Valve
Maxum II Valves and Oven Components
Service Manual, 10/2018, A5E42019844001
67
