MULTIPOSITION SELECTION VALVES

Description
The Model C25Z and C25G Cheminert valve are preferred valves for SIA and ZF, as well as stream selection valves for automated calibration systems and multiple sample stream analysis. Like the C22 series, they have a simple, flat plate rotary design.

The C25Z valve with Zero Dead Volume (ZDV) fittings (10-32), are available with 4, 6, 8, or 10 ports. The new C25G valve has 18 ports with 6-40 fittings, and is ideal for multi-component or multi-chemistry SIA and ZF applications. Nuts and ferrules are provided. Port diameters of 0.030" are available for C25Z and C25G valves. Standard specifications for all versions are 250 psi liquid at 75 deg. C.

Materials
Wetted components are manufactured from high-tech inert materials. The rotor is made of Valcon E2, a proprietary reinforced TFE blend and the stator is made of PPS, except for the C25G which has a PAEK stator. Life tests indicate that these valves, when used with fluids free of particulate and not reactive to valve components (cannot be used in prolonged contact with high concentrations of sulfuric or nitric acids, DMSO, THF or methlyene chloride) typically give more than 60,000 movements before requiring any service.

Actuators
The valves are available in a manual model, as well as with the following actuators:

• Micro-electric
• Pneumatic

The 24 VDC micro-electric actuator is a new microprocessor controlled model with state-of-the-art "intelligent" electronics. Features include:

• High speed
• Bi-directional (step either forward or backwards)
• One actuator fits all valves regardless of number of ports
• Automatic self-aligning
• Manual control with LED position indicator, step and home functions, and clockwise and counter-clockwise functions
• Remote control by contact closures (step and home functions) and BCD 5V negative true output and input (position indication and access)
• RS-232 bidirectional communication , with position indication output and position access input
• Universal power supply, 110/220 VAC to 24 VDC
• Compact size

The rapid switching capability of the micro-electric actuator has improved analyzer operation by minimizing the time during which lines are closed off as the valve switches. This gives a smoother baseline and reduces pressure fluctuations in the flow manifold. The actuator's internal intelligence allows it to be programmed for "timed injection", using Global FIA FlowTEK, or other suitable software. This feature allows reproducible timing of a full-cycle switching of the valve (load ->inject ->load, with a user defined pause in the inject position), providing partial loop injection, as well as variable volume injection. With the actuator's rapid, millisecond switching speed, timed injection can be used to inject very small volumes. Further information on this subject is available from Global FIA in a Technical Note and has been successfully applied to reproducible dilution systems.

The micro-electric actuators can be controlled either manually from a push-button or toggle-switch controller with an LED position indicator, or automatically using an appropriate device control software package such as Global FIA's FlowTEK. When using FlowTEK, up to four valves can be controlled through FlowTEK's digital output points. The valves can be controlled directly through an RS-232 serial port using FlowTEK when the micro-electric actuator is used.

The air actuator can be controlled by two solenoid air valves (available in 24 VDC and 110 VAC versions), but use of the Global FIA FlowTEK software together with the Valco Digital Valve Interface is recommended. The DVI allows the air actuator to be controlled by the simple push of a button or by low power (5 VDC) logic level signals (negative true), or by contact closures from a data system.

Service
Replacement of the valve rotor is easy. Simply remove three screws, replace the rotor, put the screws back and tighten them. With the micro-electric actuator, no adjustments are required; on initialization, the actuator automatically realigns the valve, and it is ready for use.

ORDERING INFORMATION