Sample changing chemical analysis method and apparatus

A method of analyzing a liquid chemical sample which comprises the steps of:

• (a) drawing a liquid sample into a fluid flow path by application of partial vacuum to said flow path,
• (b) blocking the flow of liquid at a point in said flow path during said application of partial vacuum so as to protect the source of said partial vacuum from the flow of said sample thereto,
• (c) introducing a portion of said sample into a flow cell of a chemical analyzer, and
• (d) analyzing said sample in said flow cell.

A method of analyzing a liquid chemical sample which comprises the steps of:

• (a) moving a liquid chemical sample from a source thereof into a first fluid flow path,
• (b) moving a liquid additive from a source thereof into a second fluid flow path,
• (c) measuring a quantity of said sample from said first flow path and a quantity of said additive from said second flow path,
• (d) mixing said measured quantities of sample and additive together,
• (e) introducing at least a portion of said mixture of sample and additive into a flow cell of a chemical analyzer, and
• (f) analyzing said mixture in said flow cell, said measuring of at least one of said liquids being accomplished by blocking off a portion of the respective said flow path containing said quantity of said liquid.

A method of analyzing a liquid chemical sample which comprises the steps of:

• (a) moving a liquid chemical sample from a source thereof into a first fluid flow path,
• (b) moving a liquid additive from a source thereof into a second fluid flow path,
• (c) measuring a quantity of said sample from said first flow path and a quantity of said additive from said second flow path,
• (d) mixing said measured quantites of sample and additive together,
• (e) introducing at least a portion of said mixture of sample and additive into a flow cell of a chemical analyzer, and
• (f) analyzing said mixture in said flow cell, said measuring of at least one of said liquids being accomplished by filling a measuring receptacle in communication with the respective said flow path to overflowing with the respective said liquid.

The method of analyzing a plurality of liquid chemical samples which comprises the steps of:

• (a) moving a first liquid chemical sample from a source thereof into a first fluid flow path,
• (b) moving liquid additive from a source thereof into a second flow path,
• (c) measuring a quantity of said first sample from said first flow path and a quantity of said additive from said second flow path,
• (d) mixing said measured quantities to produce a first mixture,
• (e) purging said flow paths of said first sample and said additive in preparation for respectively receiving a second liquid sample from a source thereof and further liquid additive from a source thereof,
• (f) introducing at least a portion of said first mixture into a flow cell of a chemical analyzer
• (g) moving said second sample from said source thereof into said first flow path,
• (h) moving said further additive from said source thereof into said second flow path,
• (i) measuring a quantity of said second sample from said first flow path and a quantity of said further additive from said second flow path, and
• (j) analyzing said first mixture in said flow cell.

A system for analyzing a liquid chemical sample which comprises:

• (a) a source of liquid chemical sample,
• (b) chemical analyzing means having a flow cell,
• (c) gas pressure/vacuum source means,
• (d) first fluid conduit means between said sample source and said flow cell,
• (e) second fluid conduit means between said flow cell and said pressure/vacuum source means, and
• (f) means for sequentially shifting said pressure/vacuum source means between a vacuum mode wherein said pressure/vacuum source means applies partial vacuum to said second conduit means to draw said sample through said first conduit means into said flow cell for analysis, and a pressure mode wherein said pressure/vacuum source means applies pressure to said second conduit means to return said sample to its said source and purge said flow cell and conduits of said sample.

A system for analyzing a liquid chemical sample which comprises:

• (a) chemical analyzing means having a flow cell,
• (b) a source of liquid chemical sample connected to said flow cell,
• (c) vacuum source means connected to said flow cell and adapted to selectively draw said sample from said sample source into said flow cell, and
• (d) microporous filter stop membrane means between said flow cell and said vacuum source means for blocking the flow of said sample liquid to said vacuum source, said filter stop membrane means having the physical characteristics of substantially blocking the flow of liquid therethrough while allowing the substantially free passage of gas therethrough.

A system for analyzing a series of liquid chemical samples which comprises:

• (a) a plurality of liquid chemical sample sources,
• (b) sample selector valve means selectively connectable with each of said sample sources,
• (c) a liquid additive source
• (d) mixing receptacle means adapted to receive measured quantitites of a selected sample and of said additive,
• (e) sample measuring means connected to said selector valve means and to said receptacle means,
• (f) additive measuring means connected to said additive source and to said receptacle means,
• (g) chemical analyzing means having a flow cell connected to said receptacle means, and
• (h) liquid transporting means connected to both of said measuring means and to said receptacle means for transporting sample from a selected sample source and additive from said additive source into the respective said measuring means, transporting measured quantitites of the selected sample and additive from the respective said measuring means into said receptacle means to produce a sample-additive mixture in said receptacle means, and transporting said mixture from said receptacle means into said flow cell for analysis.