Dilute solution apparatus

An apparatus for the preparation of a dilute solution of a sample of a fluid which apparatus comprises a valve means communicating with a dilution means, a line to said dilution means to supply diluent from a reservoir to said dilution means, a line in communication with said valve means to remove diluted sample from said dilution means through said valve means, a line in communication with said dilution means having a valve for connection to a supply of compressed gas thereto or for connection to atmospheric pressure, flow control means to control flow of diluent from said reservoir to said dilution means, and control means for controlling operation of said valve means, said valve and said flow control means, wherein said valve means comprises a two-position valve having a housing equipped with ports, the chamber of said housing containing a movable two-position valve core equipped with flow channels each of which separately communicates with two adjacent ports, a first port being in communication with inlet means for said fluid, a second port being in communication with an outlet means for said fluid, a third port being in communication with said dilution means, a fourth port being in communication with the diluted sample in said dilution means and a fifth port being for removal of said diluted sample from the apparatus, a first said flow channel communicating in its first position with said first and second ports and in its second position with said second and third ports and a second flow channel communicating in its first position with said third and fourth ports and its second position with said fourth and fifth ports, and wherein said dilution means comprises a narrow diameter cylindrical chamber connected at its upper end to the third port of said valve means and connected at its lower end to a wide diameter closed cylindrical chamber which has at the side wall at its lower end a line in communication with the fourth port of said valve means and said reservoir and has at its upper end a line having a valve therein whereby said line may be connected to a supply of compressed gas or to the atmosphere, said narrow diameter cylindrical chamber having located concentrically therein and axially slidably movable within a close fitting plunger equipped with seals to prevent fluid leakage and having at its lower end depending into said wide diameter chamber a flange end for abutting engagement with the under surface of the wide diameter chamber at the point where the narrow diameter cylindrical chamber is attached to the wide diameter chamber, and said wide diameter closed cylindrical chamber having concentrically located therein and axially slidably movable within a close fitting, double acting barrier piston equipped with seals to prevent fluid leakage and having a stirring means located within said wide diameter chamber and below said double acting barrier piston.