M20 Procedure - Valve Cap Disassembly; M20 Procedure - Actuator Disassembly - Siemens Maxum II PD PA AP Service Manual

It is important for proper procedures to be used when cleaning valve and detector parts. All
foreign contamination adhering to the part should be removed using an appropriate cleaning
solvent, such as hexane, acetone, or methanol and a dust/lint free cloth. Use of an ultrasonic
cleaner is often helpful. After cleaning, it is necessary remove excess cleaning fluid from the
components by blowing with clean air or shaking. Components must be air dry before
reassembling.
It is possible and often better to use an appropriate detergent, such as Alconox® for cleaning
instead of solvent. However, after cleaning with a detergent, it is necessary to rinse the part
thoroughly with deionized water (distilled water is also acceptable) in order to remove detergent
residue. All water must then be removed by blowing with clean air or shaking. Components
must be completely dry before reassembling.
4.4.2.8

M20 Procedure - Valve Cap Disassembly

1. Loosen the three Allen screws (16), holding the plunger valve body (13) to the valve cylinder
base (14). The screws should be loosened to the point that most of the spring pressure is
relieved (approximately 1/8" or 3.2 mm).
Do not remove the three Allen mounting screws at this time.
2. To remove valve cap (1), remove the three Allen screws (3) and six Belleville washers (2)
holding the valve cap (1) to the valve plunger body (13).
3. Remove the valve cap (1) from the plunger valve body (13).
4. Inspect the valve cap Teflon base seal disc diaphragm (4) and the Dacron disc cushion
diaphragm (5) for dirt, contamination or breaks.
Regardless of whether damage or contamination is evident, discard old seal and cushion,
and replace them with new component(s).
5. Visually inspect the rest of valve. If it is clean and in good condition, install a new disc seal
diaphragm (4) and cushion diaphragm (5).
To reassemble the valve cap, refer to the applicable steps later in this chapter.
Note
The valve cap and fittings will be cleaned before reassembly. This step will be executed
later in this chapter.
4.4.2.9

M20 Procedure - Actuator Disassembly

Note
In the next three steps, valve plungers (6) are checked for sticking.
Maxum II Valves and Oven Components
Service Manual, 10/2018, A5E42019844001
NOTICE
To prevent damage to the valve cap (1), do not place polished surface of the valve cap
against any abrasive surface. Place it on a lint free cloth free of foreign contaminants.
Valves
4.4 Model 20 Valve
63