The valves described in this manual are manufactured by VALCO Instruments Co, Houston, Texas. As
members of the W- series product line, they are known as " minivalves."The valve body is made of Nitron-
ic- 60 with 1/16 inch fittings. The W- series valves are also known as the 18900F series. These valves have
better leakage resistance and a longer life expectancy. An installed valve system is an integrated part of the
HP 5890 Series II Gas Chromatograph. Proper instrument operation will prolong the life of the valve system.
Read all the accompanying information and avoid the following operational abuses:
1) Exceeding the specified temperature and pressure ranges.
2) Plugging a valve with column packing or sample precipitation.
3) Scoring of valve surfaces with column packing or particulates in liquid or gas sample.
4) Contaminating the system with samples (noneluting materials) or poor quality support
VALCO VALVES 18900F
Basically, valves are composed of four assemblies a driver,valve body, rotor, and preload assembly.
The valve body is made of Nitronic- 60. This is a high chromium, high nickel content stainless steel, that has
excellent chemical resistance, anti galling characteristics, and high tensile strength.
(plumbing) is connected to the valve body ports by the use of provided ferrules and fittings.
All general purpose valve bodies include mechanical stops in their index lips. The stops are predetermined
to limit rotor rotation (i.e., 90 Degrees, 60 Degrees, and 36 Degrees), so the correct flow path results when
the index pin is close to or against either stop of the index lip.
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