US 3740041 A
A mixing device adapted to bubble air through a sample solution in a reaction tube without disturbing the tube and without carrying any contaminating portion of the sample solution into the next tube whose sample solution is to be mixed by the same device. The device includes a cylinder having a piston connected with an air injecting probe adapted to be lowered into the reaction tube and to inject bubbles and thereafter to be retracted into the cylinder while at the same time wiping the exterior of the probe by means of a cylindrical curtain of air. Means are provided to retain the probe in retracted position until the next mixing cycle.
Description (OCR text may contain errors)
United States Patent 1191 Jones [111 3,740,041 1 51 June 19, 1973 [5 1 REAGENT MIXING APPARATUS 2,975,119 3/1961 Emmons 92 15 ux 3,313,215 41967 B 92 86  Inventor Rlchm'dsm 3,535,206 /1970 Gft l nel... 176/36 73 Assigneez Conner Chemistry, Inc, Maunabo 3,536,449 10/1970 Astle 141/130 X Primary Examiner-Dennis E. Talbert Jr. 22 F1 d: t. 14 1971 i l l l 6 0c Attorney-Irving Sllvermann, Myron C. Cass, PP 139,311 Sidney N. Fox et a1.
 U.S. Cl 261/64, /300 R, 23/253 R,  ABSTRACT /256,73/53,9l/52,9l/450,91/466, 92/15, 41 181 222/3 222 14 222 259 R, A mixing device adapted to bubble all through a sam- 261/3], 261/]2] ple solution in a reaction tube without disturbing the s 1 1 1m. (:1 Bold 47/02 tube and Without Carrying any contaminating Portion of 58 Field of Search 261/64, 81, 121; the Sample Solution the "eXtmbe Whose sample 55 55 25 3 5 15/300 73/53, 423 lution is to be mixed by the same device. The device in- R, 425 2 425 25 92/15 91/52, cludes a cylinder having a piston connected with an air 450, 449, 466, 462; 141/181, 129, 222/3, injecting probe adapted to be lowered into the reaction 143 5; 5 R tube and to inject bubbles and thereafter to be retractedinto the cylinder while at the same time wiping 5 References Cited the exterior of the probe by means of a cylindrical cur- UNITED STATES PATENTS tain of air. Means are provided to retain the probe in retracted position until the next mixing cycle. 2,893,354 7/1959 Austin et al. 91/450 X 9 Claims, 2 Drawing Figures PRESS. 1
s i Q 34 24 l 18 VENT s 1 1 1 54 S l l 52 4O PROGRAM 36 REAGENT MIXING APPARATUS BACKGROUND OF THE INVENTION In the art of automatic chemical analyzing apparatus, a plurality of reaction tubes passing through the apparatus is required to have the sample solutions mixed at some time during the passage. Mixing is best accomplished by injecting a stream of bubbles in the sample solutions.
The problems involved include not disturbing the position of the tubes by raising or rocking or agitating the same so that the transport apparatus can be of simple construction, avoiding a complex air injection apparatus for efficacy and economy and preventing the intercontamination between the sample solutions in the respective reaction tubes.
The invention accomplishes the solution of these problems in a novel and simplified manner. Other advantages of the invention will be obvious from the specification which follows.
SUMMARY OF THE INVENTION The apparatus of the invention has a cylindrical member with a reciprocable piston on its interior. The upper end of the cylinder has a port above the piston and the lower end of the cylinder is also ported below the piston. A hollow probe is connected to the bottom of the piston and a central constricted passageway permits the probe to be extended from and retracted into the cylinder. The constricted passageway is of a diameter slightly larger than the outer diameter of the probe so that air may escape around the probe in a curtain under certain circumstances. The interior of the cylinder has a gallery connected with the lower port below the piston and through which the probe extends and in addition connected with the constricted passageway.
Air applied under pressure to the top port will drive the piston downwardly to cause the probe to extend into a reaction tube and at the same time eject bubbles of air. Thereafter, air admitted to the bottom port will pass into the gallery, raise the piston and retract the probe while at the same time forcing a curtain of air out the restricted passageway and thereby wiping the probe while it is being retracted.
Magnetic means hold the piston in its upper position with the probe retracted.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a median sectional view through apparatus constructed in accordance with the invention showing the environment in which it will be used and showing diagrammatically apparatus for operating the same; and
FIG. 2 is a chart used to explain the operation of the apparatus of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT The reference character designates the apparatus of the invention, the same being mounted in the disposition shown to some suitable support (not shown) spaced above a line of reaction tubes 12 moving along a conveyor 14. Each tube has a sample solution 16 therein which is to be mixed without disturbing the tubes 12 or interfering with their movement. Each tube is adapted to be stopped in its travel for a short time under the apparatus 10 and have its sample solution mixed thereat.
The apparatus 10 comprises a cylinder 18 having a closure 20 at its upper end providing a port 21 connected by the conduit 22 at the point A to a pneumatic line leading to a suitable valve 24. The valve 24 enables the conduit 22 to be connected to a source of pressure 26 or to be closed off. The lower end of the cylinder 18 has a lateral port 30 connected by the conduit 32 at the point B to a pneumatic line leading to the valve 24 and capable of being vented as at 34 or connected to the source of pressure 26. The cylinder has a free piston 36 reciprocable therewithin, and a central hollow probe 38 connects with the piston 36 in such a manner that its upper end 40 opens above the piston. The lower end or tip 44 of the hollow probe 38 may extend out of the cylinder 18 by way of the conical plug 42 as shown in the drawing, or may be retracted! when the piston 36 moves upward, at which latter time the tip 44 will be located at the point 46 shown in broken lines.
The port 30 opens into a gallery 48 formed in the plug 42 and connecting with an axial passageway 50 slightly larger in diameter than the outer diameter of the probe 38.
Preferably, the upper end of the piston 36 carries a magnetic disc 52 adapted to cooperate with the lower surface of the closure 20 magnetically so that at the upper end of the piston stroke, the piston 36 will tend to remain adhered to the plug 20 .as shown by the broken line outline at 36. The material of plug 20 and disc 52 may be any suitable substance which can be permanently magnetized such as rubber with iron powder mixed therein.
In operation, as shown in the chart of FIG. 2, assume that the piston 36 is at the top of its stroke and the probe is fully retracted. A reaction tube 12 moves into the position shown directly below the device 10. Through a suitable programming device 54, the valve 24 is caused to provide the connections designated step 1. Air pressure is applied to the port 21 and the port 30 is vented to the atmosphere. Air entering the upper end of the cylinder 18 forces the piston 36 to leave its magnetic adherence to plug 20 and drives the piston 36 downwardly extending the probe 33 into the sample solution 16 of the tube 12. Continued application of pressure causes bubblesshown at 56 to pass out the end 44 which may be suitably restricted by a choke 58 to achieve the desired size of bubbles. After a short period of time, at which the step 2 occurs, with the connection to port 30 being either closed or vented, step 3 occurs.
In step 3, the valve 24 is operated to close conduit 22 so that the port 21 is closed and the conduit 32 is connected to pressure source 26 so that pressure is applied to the port30. Air entering the gallery 48 exerts pressure against the bottom of the piston 36 raising it and starting to retract the probe 38 from the sample solution 16. Since the port 21 is closed, air captured within the cylinder will escape to the opening 40 and pass down the interior of the probe 38 to clear its interior and bubble out of the solution while the probe is moving. Also, air passes down from the gallery 48 through the passageway 50 surrounding the exterior of the probe 38 with a curtain of air at high pressure and blowing the moisture off the surface of the probe so that when it is fully retracted it is dry. At this time, the piston 36 is in position 36 poised for the next cycle. This is step 4 with both parts vented.
The ability to retract the probe 38 enables the bottom end of the plug 42 to be positioned closely to the upper ends of the passing reaction tubes 12. Space is conserved thereby. The probe 38 is preferably made of soft plastic so that it is light in weight and so that any failure of synchronization of its operation with the movement of the conveyor 14 will not result in jamming or breakage.
The valve 24 may comprise a plurality of valves to accomplish the desired connections.
Modifications in the structure and programming and the valving sequence and arrangement can be made without departing from the spirit or scope of the invention as defined in the appended claims.
What it is desired to secure by Letters Patent of the United States is:
1. A reagent mixing apparatus comprising:
A. a cylinder adapted to be poised over a moving line of reaction tubes with the upper ends of the tubes passing close to the bottom end of the cylinder, said cylinder having an upper port and a lower port,
B. a piston reciprocable in the cylinder between the ports and having a hollow probe secured to the bottom end thereof with the probe having its upper end opening to the top of the piston,
C. means closing off the top of said cylinder but for said upper port,
D. means closing off the bottom end of the cylinder but having a central axially extending passageway through which the probe may be extended from and retracted into the cylinder,
E. a chamber formed within the cylinder below the piston at the bottom end of its stroke, connected with the lower port and being constructed and arranged to divide any air introduced through said lower port to raise the piston and retract the probe while at the same time blowing air through the central passageway around the periphery of the probe while it is being retracted,
F. the upper port adapted to be connected to a source of air pressure so that when such air pressure is applied thereto the piston will be driven downwardly and extend the probe out of the bottom end of the cylinder while at the same time air will be passed through the probe and out the bottom end thereof, and
G. means for retaining the piston at the upper end of its stroke when no air is being introduced to the upper port.
2. Apparatus as claimed in claim 1 in which the closing off means comprise a plug in the bottom end of the cylinder and the chamber and axially extending passageway are formed in the plug.
3. Apparatus as claimed in claim 2 in which the chamber comprises a gallery coaxial with the passageway and having a diameter greater than said passageway, the lower end of the chamber being connected with said passageway so that the probe extends through the center of the gallery while the upper end of the gallery opens to the bottom of the piston.
4. Apparatus as claimed in claim 3 in which the lower port opens in a lateral wall of said gallery.
5. Apparatus as claimed in claim 1 in which said retaining means comprise magnetically adherable structures on at least the facing surfaces of the means closing off the top of the cylinder and the upper part of the piston.
6. Apparatus as claimed in claim 1 in which the probe is formed of tubing of soft plastic material.
7. Apparatus as claimed in claim 1 in which the probe has a substantially larger internal diameter throughout its major extent than it has at its lower end.
8. Apparatus as claimed in claim 2 in which the means closing off the top of the cylinder comprises a closure and the upper port comprises a conduit extending through the closure coaxially therewith.
9. The combination of the apparatus of claim 1 with a source of air pressure, venting means and valve means including connections to said ports and control means for connecting said upper port to said source of pressure when said lower port is vented, for thereafter connecting the lower port to said source of pressure when said upper port is closed and thereafter venting both said ports.