Valves
Caution: We recommend to exchange Cheminert fittings, supplied
with Valco Valves, by Upchurch fittings, unless you want to keep track of
the kind of ferrules you will use to secure the tubing into a fitting.
A mismatch of ferrules will cause a leak.
Flow Injection systems use a two position valve, where the volume of the injected sample is defined by the volume of an external loop. Sequential Injection systems use a multiposition valve, where the volumes of sample and reagents are controlled by a syringe pump. Conventional two and multiposition valves described on this page are not transparent to the user, a feature which prevents visual inspection of valve function and makes identification of valve malfunction difficult. FIAlab “Lab-on-Valve”® technology avoids this problem, and brings additional advantages, especially for the Sequential Injection technique.
Two Position Injection Valve
With the valve in Position A, sample flows through the external loop while the carrier flows directly through to the detector. When the valve is switched to Position B, the sample contained in the sample loop and valve flow passage is injected in the detector.
The volume of injected sample is defined by the volume of the external loop.
Cheminert® Injection Valves for Flow Injection Analysis
Model C22 Sample Injector - 1/4-28 fitting
C22 valves are used for sample injection or column switching. The valve caps have female threads for direct connection of lines – no couplings are required. Multicolored flangeless fittings are included.
Available models:
C22-3186EH 6 port, 2 position external sample injector valve
C22-3188EH 8 port, 2 position external sample injector valve
C22-3180EH 10 port, 2 position external sample injector valve
C22-3192EH 12 port, 2 position external sample injector valve
All valves come with an actuator and power supply.
Two Position Injection Valve
Multiposition Valves
Sample and reagents are sequentially aspirated by syringe pump into the holding coil, mixed by flow reversal and then transported to the detector. Turning of the rotor switches the position of the groove between the central port and peripheral ports. For details see Principles or the complimentary CD Tutorial.
Schematic of a Multiposition Valve
Cheminert® Valves for Sequential Injection Analysis
Model C25 Multiposition Stream Selector - 1/4-28 fitting
The Cheminert® Model C25 valve for Sequential Injection and column switching selects and isolates one of 6, 8, or 10 ports, with the other ports being dead-ended. The Model C25 has female 1/4-28 threaded fitting details for direct connection of lines - no couplings are required. Multicolored Cheminert flangeless fittings are included.
Available models:
C25-3186EMH 6 position external selection valve
C25-3188EMH 8 position external selection valve
C25-3180EMH 10 position external selection valve
All valves come with a actuator and power supply.
10 port Multiposition Valve with Cheminert Fittings
