Equilibrating instrument for preparing quality control solutions

An equilibrating instrument for preparing quality control solutions of a liquid and gas including, in combination:

• (a) a housing having at least one gas inlet for connection to a source of compressed gas;
• (b) at least one humidifier in said housing for receiving gas from said inlet, said humidifier having an outlet connection on the exterior of said housing;
• (c) a heat block secured to said housing and having at least one elongated vertical cavity open at the top and having a decreased diameter bottom opening to define an internal upwardly facing annular shoulder;
• (d) thermostatically controlled means in said housing for maintaining said heat block at a given constant temperature;
• (e) a diffusion tube having an open top and terminating at its lower end in a gas inlet nipple defining an external downwardly facing annular shoulder, said tube being receivable in said cavity with its downwardly facing annular shoulder seated on said upwardly facing annular shoulder of said cavity and its nipple extending through said bottom opening to a point exterior of said housing so that said tube is supported in said cavity and yet readily manually removable out the top of said cavity;
• (f) a diffuser means in the lower portion of said diffusion tube;
• (g) a flexible gas conveying tubing exterior of said housing connecting said humidifier outlet to said diffusion tube nipple so that gas can be passed from said humidifier upwardly through said diffusion tube;
• p1 (h) a valve block positionable on top of said housing to overlie the upper open end of said diffusion tube, said valve block including a valve body having first, second and third ports;
• (i) a sample selecting tube connecting to said third port and positioned to extend under the valve block downwardly into the open top of said diffusion tube to terminate close to said diffusion means;
• (j) first and second syringes connected to said first and second ports;
• and
• (k) a manually operable valve member extending into said valve body for connecting said first and third ports together when in a first position and connecting said second and third ports together when in a second position whereby a liquid to be equilibrated with gas can be injected into said diffusion tube by said first syringe with said valve member in said first position and gas passed into said diffusion tube and through said diffusion means to bubble up through said liquid until equilibration at said given temperature is completed and thereafter, a small "dead sample" withdrawn into said first syringe and said valve member then turned to its second position to permit withdrawal of a sample of the prepared quality control solution into said second syringe for quality control purposes, and whereby said flexible gas conveying tubing can be easily disconnected after equilibration if it should be damaged or contaminated and replaced without disassembling other component parts of the instrument and whereby said diffusion tube itself can be removed and disposed of or easily cleaned and replaced without affecting other components by simply lifting off said valve block and removing the tube out the open top of said cavity.