Liquid transfer valve

A liquid transfer valve including movable valve portions. A second valve portion is movable with respect to a first valve portion to allow a probe to extend therethrough to pick up a sample liquid. Upon probe retraction, the second valve portion is movable to a position which allows the sample liquid to be injected into the valve where it is diluted and carried to a remote detector or delivery point.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to the field of measuring and testing instruments. 
More particularly, the invention relates to the field of liquid sample 
handling in measuring and testing instruments. In still greater 
particularity, the invention is a liquid transfer valve which is utilized 
with a movable probe. By way of further characterization but not by way of 
limitation thereto, the invention is a valve having a movable portion and 
a stationary portion which, in one position, allows the movable probe to 
access a sample substance and, in a second position, allows the sample 
substance to be ejected from the probe, combined with a diluent in a fixed 
ratio, and delivered to a remote location. 
2. Description of the Related Art 
Measuring and testing instruments utilizing automated sample handling 
devices may be complex to build and operate when a number of liquids are 
to be moved to various locations. These instruments normally require that 
a sample fluid be diluted with a second fluid or reactant before being 
subjected to testing. This dilution must be accomplished quickly in order 
to allow a large number of samples to be tested. It may also be desirable 
to introduce calibration standards into the system at various time 
intervals. In addition, while washing of the probe is necessary to prevent 
contamination of subsequent sample liquids, this washing should be 
accomplished quickly and easily. To minimize the time required to complete 
these functions it is desirable to minimize the amount of system movement 
required. 
Prior devices such as that shown in U.S. Pat. No. 3,747,412 issued to A. R. 
Jones on July 24, 1973 employ valves which include sections movable with 
respect to one another. The apparatus described in the above referenced 
U.S. Patent is a trapped volume device in which the probe is connected to 
a movable valve portion. A sample liquid is drawn through the probe and 
into the valve where a predetermined volume of the sample liquid is 
trapped. The sample liquid is combined with a fixed volume of another 
liquid after movement of the valve portions which align conduits connected 
to sources of these other liquids. While suited for its intended purpose, 
this device does not allow probe movement with respect to the valves and 
washing of the probe must be accomplished in a separate step. In addition, 
the device is complicated and requires much supporting hardware. 
SUMMARY OF THE INVENTION 
The invention is a liquid transfer valve which is employed with a movable 
probe. The valve includes a first stationary valve portion and a second 
movable valve portion. Movement of the valve portions with respect to one 
another into a first configuration, hereinafter designated as pickup 
position, allows the probe to move through these valve portions to pick up 
a sample liquid. After retraction of the probe through the movable valve 
portions, movement of the movable valve portion into a second position, 
hereinafter referred to as delivery position, allows the sample liquid to 
be injected into a passageway where it is mixed with another liquid. 
In the pickup position a first access port in the first valve portion and a 
clearance hole in the second valve portion are aligned, allowing passage 
of the probe therethrough. Upon retraction of the probe, the second valve 
portion moves with respect to the first valve portion such that a 
passageway in the second valve portion is aligned with the first access 
port in the first valve portion. A conduit in the first valve portion 
communicates with the first access port and this conduit is connected to a 
source of diluent or reactant. In the delivery position the sample liquid 
is delivered from the probe into the first access port at the same time a 
diluent is delivered through the conduit at a predetermined ratio. These 
liquids are comingled and the mixture is transported to a detector or 
remote location through the passageway in the second valve portion. A seal 
in the first access port contacts the probe to seal and cleanse the 
outside of the probe upon its retraction from the pickup position. 
Suitable valving external to the liquid transfer valve allows liquids to 
be dispensed through the conduit and through the probe to dilute samples, 
add and dilute calibration standards, and wash both the probe and the 
valve portions. The dispensed solution is then conducted through the 
passageway in the second valve portion and delivered to detectors or other 
remote locations. Sample pickup, delivery, dilution, calibration, and 
washing of the probe and valve is thereby accomplished with minimum probe 
and valve movement thereby simplifying these operations.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, a probe 11 extends through a liquid transfer valve 12. 
Valve 12 includes a first valve portion 13 and a second valve portion 14. 
A driving rod 15 is connected to second portion 14. Driving rod 15 is also 
connected to a conventional driving source such as a stepper motor (not 
shown). Probe 11 passes through an access port 16 in first valve portion 
13 and a clearance hole 17 (illustrated by the dotted lines in second 
valve portion 14). Probe 11 is insertable into a sample liquid 18. A 
passageway 19 extends through second valve portion 14 as will later be 
described. Probe 11 is connectable to a suitable pumping and valving 
system by flexible tube 21. First valve portion 13 and second valve 
portion 14 are biased together by a spring 22 employed with a connector 
20. Connector 20 allows rotational movement of second portion 14 with 
respect to first portion 13. 
Referring to FIG. 2, probe 11 is shown connected to an elevator mechanism 
which includes a supporting portion 23 and a threaded rod 24. Threaded rod 
24 is journaled in a conventional driving mechanism (not shown) to allow 
probe 11 to be raised and lowered. Passageway 19 extends into second valve 
portion 14. A conduit 25 extends through first valve portion 13 as will 
later be described. Passageway 19 is connected to a suitable detector, 
remote station, or waste container by flexible tube 26. Conduit 25 is 
connected to a suitable valving and pumping system by flexible tube 27. 
Referring to FIG. 3, probe 11 and liquid transfer valve 12 are shown in the 
pickup position. That is, probe 11 extends through a seal 28, access port 
16, and second access port 17 and into sample liquid 18. Conduit 25 
communicates with access port 16. Passageway 19 is effectively sealed from 
communication with access port 16. Probe 11 is connected to a sample pump 
(not shown) by flexible tube 21. 
Referring to FIG. 4, probe 11 and liquid transfer valve 12 are shown in the 
delivery position. That is, probe 11 has been retracted such that its tip 
is positioned in access port 16 and second valve portion 14 has been 
rotated such that passageway 19 communicates with access port 16. 
Clearance hole 17 is effectively sealed from access port 16. Conduit 25 
communicates with access port 16. Seal 28 contacts probe 11 and first 
valve portion 13. Probe 11 is connected to a pump system through suitable 
valving by flexible tube 21. 
MODE OF OPERATION 
Referring to FIGS. 1 and 3, second valve portion 14 is in the pickup 
position such that access port 16 and clearance hole 17 are aligned in a 
plane parallel to the direction of travel of probe 11 thus allowing probe 
11 to access sample liquid 18. This position for probe 11 is referred to 
as the pickup position. In this position, probe 11 picks up sample liquid 
18 which is aspirated therein by a sample pump connected to flexible tube 
21. Second valve portion 14 is rotatable on connector 20 which is spring 
loaded to bias second valve portion 14 against first valve portion 13. 
Driving rod 15 is used to rotate second valve portion 14 into the desired 
positions. 
Referring to FIG. 2, after the sample liquid has been picked up probe 11 is 
raised by the elevator mechanism. Second valve portion 14 is then rotated 
by driving rod 15 to the position shown in FIG. 4. The position of probe 
11 and second valve portion 14 shown in FIG. 4 is referred to as the 
delivery position. That is, sample liquid 18 taken into probe 11 is 
delivered into access port 16 while, at the same time, a diluent liquid is 
delivered to access port 16 through conduit 25. The sample liquid and 
diluent liquid pass downward into passageway 19 where they mix and are 
carried through flexible tube 26 to a desired location. The raising of 
probe 11 into the delivery position serves to cleanse the outside of probe 
11 as it passes seal 28. That is, contact of probe 11 with seal 28 removes 
any sample liquid remaining on the outside of probe 11. In the delivery 
position sample liquids, calibration standards, or wash liquid may be 
dispensed into probe 11 through flexible tube 21 while, at the same time, 
a diluent or wash liquid is dispensed through flexible tube 27 into 
conduit 25. Thus, probe 11, conduit 25, and access port 16 may be washed 
and the wash solution is conducted through passageway 19 and flexible tube 
26 thereby also washing them. The diluent and wash solutions may contain 
reactants, calibration standards, or substances compatible to the desired 
analysis or sample handling. The valve logic may also deliver only 
undiluted sample, wash solution, or diluent in the delivery position. 
Because a minimal amount of movement is required to pick up, dilute, and 
deliver a sample liquid or standard, a significant saving in time and 
accessory apparatus is achieved. In addition, the probe and valve may be 
washed while in the delivery position. Thus, rotation of second valve 
portion 14 into the pickup position shown in FIG. 3 and lowering of probe 
11 is all that is required to begin another sample dilution. Unnecessary 
motion is thus eliminated. Probe 11 is only required to move vertically to 
pick up sample liquids 18 from movable containers. Also, in the pickup 
position probe 11 may aspirate slugs of air before and/or after the sample 
to separate it from other liquid that may be in probe 11 or flexible 
tubing 21. Also, while in the pickup position, a reversible diluent pump 
connected to flexible tube 27 may aspirate air slugs if so desired. While 
in the delivery position, these air slugs may be delivered along with the 
liquids if such is desired. 
Advantages of the liquid transfer valve include the elimination of leaky or 
worn septums. There is no dripping of sample liquid from outside of the 
probe as it passes through a septum. Also, the device enables air slugs to 
be drawn into the probe and/or the diluent line and dead valve space is 
minimized resulting in a low hold-up volume. Also, no stirring is required 
for mixing of the sample liquid and the diluent liquid because the liquid 
flow through passageway 19 is sufficient to mix the liquids. The device 
also allows calibration standards to be easily introduced into the system. 
While particular forms of the invention have been disclosed with respect to 
a preferred embodiment thereof, it is not to be so limited as changes and 
modifications may be made without departing from the scope of the 
invention. For example, more than one conduit could be employed in first 
valve portion 13 if more than one liquid is desired to be combined with 
the sample liquid. In addition, more than one passageway in second valve 
portion 14 could be provided such that delivery of diluted sample liquid 
could be accomplished to multiple locations. Any number of conduits and 
passageways could be employed without departing from the inventive 
concept. Additionally, while second valve portion 14 was rotatably mounted 
to first valve portion 13, it would be possible to mount second valve 
portion 14 such that it would slide into the pickup and delivery 
positions. Another possibility would be to have lower portion 14 hinged 
such that it could drop away from first portion 13 to allow probe access 
through portion 13. Upon probe retraction, second portion 14 would be 
again positioned adjacent first portion 13 in the delivery position. Thus 
only passageway 19 would be required in second valve portion 14 
eliminating the need for second access port 17. 
The foregoing description, taken together with the appended claims, 
constitutes a disclosure which enables one skilled in the art and having 
the benefit of the teachings contained therein to make and use the 
invention. Further, the structure herein described constitutes a 
meritorious advance in the art which is unobvious to such skilled workers 
not having the benefit of these teachings.