SAMPLE INJECTION VALVES

Description
The Model C22 and C22Z Cheminert valves have rapidly established themselves as popular injection valves for FIA. Their success is attributable in part to their simple flat plate rotary design and rapid switching capability (micro-electric actuation model).

The C22 valves with 1/4-28 threads, and the C22Z valves with 10-32 threads, are available with 4, 6, 8, or 10 ports. Nuts and ferrules are provided. Port diameters of either 0.030" or 0.060" are available for C22 valves and 0.030" for all C22Z valves. Standard specifications for all versions are 250 psi liquid at 750 C. On request, the pressure rating can be as high as 600 psi liquid.

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. 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 switching - less than 100 milliseconds
• Partial loop injection - with suitable software such as FlowTEK
• Variable volume injection with a single loop - with FlowTEK
• Automatic self-aligning
• Manual control with position indicator
• Remote control by contact closures or TTL level logic signals
• RS-232 bi-directional communication
• 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