AU8326887A - Method and apparatus for conveying information in a liquid sample transport system - Google Patents

Description

METHOD AND APPARATUS FOR CONVEYING INFORMATION IN A LIQUID SAMPLE TRANSPORT SYSTEM

1. BACKGROUND OF THE INVENTION 1.1 Field of the Invention

The present invention relates to transport systems for liquid samples. The invention lends itself to use in a wide diversity of systems, including automated clinical blood analyzers which utilize small-bore conduits to transport blood samples from point to point within the instrument, industrial systems such as networks of conduits used in monitoring the contents of reaction vessels to optimize product yield and quality, and pipelines wherein relatively large sample throughput is possible.

In all of these types of systems, whereby liquid samples are transported in a conduit via a flowing stream, it would be desirable to provide a way of conveying certain information within the liquid sample or the flowing stream itself. Thus, in an automated blood analyzer it would be desirable to identify each patient corresponding to each blood sample flowing through the analyzer conduit. Moreover, it would be desirable if information could be incorporated with a particular sample at some upstream location in the analyzer conduit directing a particular analysis out of a menu of possible analyses to be performed on the sample at a conduit location further downstream.

In the case of an industrial system, such as a reaction vessel monitoring system, whereby samples are periodically taken of reaction vessel contents and transported via a closed conduit to a remote location for analysis, it would be advantageous to incorporate information directly into the sample stream. For example, a particular reactor could be identified downstream. Alternatively, a valving system could be put in place whereby the flowing stream could be shunted automatically to any of several downstream locations depending on the information associated with the stream or sample.

Accordingly, the field of the invention is broad, and encompasses a myriad of potential applications and uses, ranging from medicine to chemical analysis to industrial monitoring processes to bulk pipeline transport. 1.2 Background of the Invention

Although the present invention comprises a breakthrough in liquid transport, in that the inventors herein, are unaware of any previous efforts to convey information such as described herein through a liquid transport system, it is relevant at this juncture of the disclosure to point out as background information the types of systems wherein the invention is particularly applicable.

An automated apparatus for the analysis of liquid samples as a flowing stream was disclosed in each of United States Patent Nos. 2,797,149 and 2,879,141, both assigned to the instant assignee. In this basic apparatus _r the liquid samples are sequentially aspirated from containers located on a turntable arrangement and into a conduit, each sample being separated from the next successive sample by a segment of air. Customarily, the conduit is made of glass, rubber or poly- vinylchloride. As the aqueous liquid samples wet the inner surface of the conduit, a residue or thin film of sample liquid adheres to the surface during passage along the conduit. This adhered liquid film is, in part, taken up by the next successive liquid segment, which is thereby contaminated. Various expedients have been successfully utilized to reduce this intersegment contamination.

United States Patent No. 3,479,141, assigned to the instant assignee, discloses an automated analytical apparatus wherein a series of aqueous liquid samples are processed as a flowing stream with substantially no contamination between samples by the mixing of a portion of a prior sample with a succeeding sample (carryover) . In such, apparatus, a liquid, which is immiscible with the liquid samples and which preferentially wets the interior conduit wall, is referred to as a carrier fluid and is used to pass the successive samples along the conduit. The individual samples are encapsulated in the immiscible liquid and do not contact the conduit wall, whereby no sample residue adheres to the wall and contamination of a next liquid sample is avoided. The individual sample segments are surrounded by and flow in a stream of the immiscible liquid, which can be silicone. An air segment can be provided between sample segments and within the immiscible fluid to insure that successive sample segments do not coalesce.

United States Patent No. 4,253,846 describes a system wherein discrete liquid sample segments are conveyed along a conduit in an immiscible liquid stream, and described in United States Patent No. 3,479,141 above. As in United States Patent No. 3,479,141, cited above, the immiscible fluid fully encapsulates each sample segment which is passed along the system. In such a system, reagents are injected, on a selected basis, into the successive liquid samples as they are passed along a portion of the conduit, so as to reach with the same. United States Patent No. 4,259,291, also assigned to the instant assignee, illustrates a mode of introducing sample to establish a stream of alternating gas and liquid segments to which diluent is later added.

United States Patent No. 4,526,754, assigned to the present assignee, describes a system to which the present invention is especially applicable. This patent, which is incorporated herein in its entirety by the present reference thereto, relates to a sample transport system whereby a plurality of different samples can be conveyed over long distances in a single conduit. Moreover intersample mixing or contamination is avoided. The system basically comprises a liquid coating on the interior walls of the conduit, which coating is immiscible with both the samples and the flowing stream with which they are associated within the conduit. The flowing stream comprises a carrier stream of alternating gas segments and a carrier liquid immiscible with the conduit coating. In use, sample liquids are injected within the gas segments so as to intersect the segments, thus providing smaller gas segments at either end of the sample segment. Upstream of the point of sample injection is provided a means for detecting the initial gas segment, i.e., prior to its being injected with sample liquid, to provide signals to cause sample injection at the desirable point within the gas segments.

Despite the wide range of existing liquid sample transport systems, such as those described above, the present inventors are aware of no teaching of incorporating complex information directly into the flowing stream, such as is taught herein. The present state of the art of transport systems is bereft of such a way of information conveyance. The present invention, on the other hand, provides a way of improving the prior systems by enabling the identification of particular samples, their source, their nature, and by directing a virtually limitless diversity of downstream processes to be performed on the sample, such as selective analyses, routing of samples to a multiplicity of ultimate stations, and many other sample manipulations.

2. SUMMARY OF THE INVENTION

Briefly stated, the present invention comprises a method and apparatus for providing information with respect to a liquid sample in a flowing stream.

The method comprises causing at least one liquid sample to flow through a conduit with the flowing stream; incorporating with the sample or the stream at a first conduit location a sequence of aliquots of a fluid immiscible with the sample or stream, the sequence of aliquots having at least one parameter corresponding to the information to be provided; detecting the parameter of the sequence at a second conduit location, the second conduit location being downstream of the first conduit location; and interpreting the detected parameter to provide the information.

The apparatus of the present invention comprises a conduit having a first conduit location and a second conduit location downstream from the first conduit location; an inlet means communicating with the first conduit location, for incorporating with the liquid sample or the flowing stream a sequence of aliquots of a fluid immiscible with the sample or stream, the sequence of aliquots having a parameter corresponding to the information to be provided; a detection means provided at the second conduit location, the detection means being capable of detecting the parameter of the sequence; and means for interpreting the detected parameter to provide the information.

3. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a detail view of a preferred embodiment of the present invention, whereby an inlet means communicating with a conduit is depicted, as well as the introduction of a sequence of fluid aliquots into the flowing stream.

Figure 2 illustrates typical aliquot spacing within the flowing stream.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention relates broadly to liquid transport systems in general, whereby one or more liquid samples is transported through a conduit via a flowing stream. The flowing stream can be continuous or intermittent. Thus it can be part of an automatic chemical analyzer wherein samples are intermittently introduced into a conduit with spacing segments such as air between samples, or the flowing stream can itself comprise a carrier liquid, such as one immiscible or miscible with the sample. As presently envisioned, the sample is preferably aqueous.

The fluid of which the segments of aliquots is comprised likewise has wide latitude, provided it be immiscible with the sample and flowing stream. Thus, it can be a gas or a liquid. Preferably the fluid is a gas such as air or nitrogen, or an immiscible oil such as a silicone or fluorocarbon. Especially preferred is the use of air.

The fluid aliquots can be incorporated with the sample or stream at any place with respect to the sample convenient for the particular application. While it is preferable to introduce the aliquots directly into the sample near its ^* downstream edge, they could also be placed anywhere else within the sample, i.e., near its middle or near its upstream edge. Moreover, the aliquots could be incorporated outside the sample boundaries, i.e., in the flowing stream or carrier liquid.

The sequence of the aliquots introduced is provided with one or more parameters which is later detected and interpreted to provide the information. Such parameter can be spacing between aliquots, wherein n number of aliquots defines n minus 1 spaces. If the sequence provides five aliquots, four spaces occur. If these are made of two distinct volumes, then 16 possible codes can be incorporated in such five aliquot sequences. For purposes of illustration, if a long space is designated as 1 and a short space is 0, sequences corresponding to 0000, 0001, 0011, 0111, 1111, 1110, 1100, 1000, 0010, 0100...are attainable, equivalent to the numbers 0 through 15. Such spacing sequences are then detected at a conduit location downstream from where the aliquots were introduced, and are then interpreted to provide the informa¬ tion ascribed to the sequences. Thus each sequence can correspond to some sample information, such as its source, its content, directions for further operations to be performed on the sample such as an analysis for a particular component in the sample, and other desirable information.

In addition to the sequence of aliquot spacing, other sequence parameters can be employed. For example the fluid aliquots can contain variations in color or optical density which can be detected using a spectrophotometer. Still further, spacing and optical parameter variations can be used concurrently. Clearly there are many other parameters of the aliquot sequence which can be relied upon to convey informa¬ tion which would occur to one skilled in the art, and which would be within the spirit and scope of the present invention.

When the parameter is detected at conduit location downstream of the inlet location, it is interpreted; that is, the detected parameter is subjected to a recognition process such as human correlation, computer manipulation or other "decoding" operation. In the case where the information desired is identification of which one of several reaction vessels the sample originated from, for example, a sequence of two fluid aliquots (defining one space therebetween) might be visually interpreted by the operator as corresponding to "reaction vessel 1"; two spaces signifying "reaction vessel 2"; and so forth.

Alternatively, a binary system of long and short spaces, such as described infra, could be used in conjunction with a spectrophotometer to generate a signal. Such a signal could then be used as input data for a computer programmed to perform some process, either on the sample or otherwise. Thus, the computer could provide a printout in response to the sequence parameter; it could direct the performance of a particular analysis on the liquid sample; it could actuate a system of automatically operated valves to direct a particular sample to one of several shunt pathways from the conduit, such as to individual storage tanks, depending on the nature of the sample. These and other applications of the invention would be apparent as needs present themselves.

The conduit of the present invention can vary widely as to its size and composition. However, it is presently preferred that its interior surface, i.e. that part of the conduit wherein the liquid sample and flowing stream are contained, be coated with a substance which wets the conduit, but which is immiscible with the liquid sample and the flowing stream, as well as with the fluid aliquots. Especially preferred is that the conduit be a tube comprising a fluorocarbon polymer such as Teflon or Kel-F, the interior walls of which are coated with a silicone or fluorocarbon oil. The sequence of aliquots is introduced through an inlet means at a first conduit location, whereas the inlet can be manual or automated, and might comprise any suitable physical means for introduction of the fluid aliquots, it is preferred that it comprise an air supply provided with a valve means capable of intermittently opening and closing the air supply to provide the sequence of aliquots. Such an embodiment is depicted by Figure 1.

Thus inlet means 5 comprises an air source 6, valves 3 and 4 and the connective pipes 7 and 8. Valves 3 and 4 operate in sequence to introduce a fluid aliquot air bubble 9 which is carried downstream with the sample and flowing stream in conduit 1. A previously introduced aliquot bubble 2 is shown in its downstream position.

Figure 2 depicts a typical sequence of fluid aliquots 1, 2, 3 and 4. In this embodiment is shown variation in spacing between aliquots as described infra. The aliquots are -travelling through conduit 1 with the sample and flowing stream.

As mentioned previously, the present invention is especially adaptable to a sample transport system such as that depicted in United States Patent No. 4,526,754 which issued on July 2, 1985 to Donald A. Burns, et al. That patent is hereby incorporated into and made a part of the present disclosure.

SUBSTITUTESHEET

Claims (16)

WHAT IS CLAIMED IS:

1. A method for providing information with respect to a liquid sample in a flowing stream, the method comprising causing at least one liquid sample to flow through a conduit with the flowing stream; incorporating with the sample or the stream at a first conduit location a sequence of aliquots of a fluid immiscible with the sample or stream, the sequence of aliquots having at least one parameter corresponding to the information to be provided; detecting the parameter of the sequence at a second conduit location, the second conduit location being downstream of the first conduit location; and interpreting the detected parameter to provide the information.

2. The method of claim 1 in which the liquid sample is aqueous.

3. The method of claim 1 in which the fluid is a gas.

4. The method of claim 1 in which the fluid is air.

5. The method of claim 1 in which the fluid is incorporated in the flowing stream or near the downstream edge of the liquid sample.

6. The method of one of claims 1 through 5 in which the parameter comprises the spacing between the aliquots in the sequence.

7. The method of one of claims 1 through 5 in which the parameter comprises the spacing of the aliquots and the volume of the aliquots in the sequence.

8. The method of one of claims 1 through 5 in which the information is conveyed to a sample processing means wherein the processing means performs a process on the sample in response to the information.

9. The method of claim 8 in which the process comprises the analysis of the sample for an analyte.

10. An apparatus for providing information with respect to a liquid sample in a flowing stream, the apparatus comprising a conduit having a first conduit location and a second conduit location downstream from the first conduit location; and inlet means communicating with the first conduit location for incorporating with the liquid sample or the flowing stream a sequence of aliquots of a fluid immiscible . with the sample or stream, the sequence of aliquots having a parameter corresponding to the information to be provided; a detection means provided at the second conduit location, the detection means being capable of detecting the parameter of the sequence; and means for interpreting the detected para¬ meter to provide the information.

11. The apparatus of claim 10 in which the inlet means comprises an air supply provided with a valve means capable of intermittently opening and closing the air supply to provide the sequence of aliquots.

12. The apparatus of claim 11 in which the valve is automatically opened and closed to provide the sequence of aliquots.

13. The apparatus of one of claims 10 through 12 in which the conduit additionally comprises a third conduit location which is provided with a sample processing means, wherein the processing means is capable of performing a process on the liquid sample in response to the information.

14. The apparatus of claim 13 in which the processing means comprises a device capable of analyzing the sample for the presence of at least one analyte.

15. The apparatus of one of claims 10 through 12 in which the conduit comprises a substance coated at its internal surface with a liquid which wets the substance, but which is immiscible with the liquid sample, the flowing stream and the fluid aliquots.

16. The apparatus of claim 15 wherein the substance is a fluorocarbon polymer.