Sample-sucking condition checking method and system

• US 4,893,515 A
• Filed: 12/20/1988
• Issued: 01/16/1990
• Est. Priority Date: 09/18/1986
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Uchida, Makoto
• Primary Examiner(s): Raevis, Robert R.
• Application Number:
  US07/287,553
• Time in Patent Office: 392 Days
• Field of Search: 73/863, 73/863.01, 73/863.02, 73/863.03, 73/864.34, 73/864.73, 73/863.83, 73/864.11-864.18, 73/864.21-864.25, 422/100
• US Class Current: 73/864.34
• CPC Class Codes: G01N 2035/1018 Detecting inhomogeneities, e.g. foam, bubbles, clots
• CPC Class Codes: G01N 35/10 Devices for transferring samples or any liquids to, in, or from, the analysis apparatus, e.g. suction devices, injection devices G01N35/0099 takes precedence
• CPC Class Codes: G01N 35/1016 Control of the volume dispensed or introduced
• CPC Class Codes: G01N 35/1095 for supplying the samples to flow-through analysers for a specific analyser see relevant groups, e.g. under G01N15/00, G01N21/00, G01N27/00, G01N30/00, H01J49/00

Abstract

In order to check a sample sucking condition at the sampling nozzle, minimum and maximum pressure values in normal sample sucking condition, and a judging value used in a formula for determining the sample sucking condition are preset. A pressure level before the start of the sample suction, a pressure level during the sample suction, and a pressure level immediately before the completion of the sample suction is measured. A clogged condition is detected during the sample suction. A normal condition and a no-sample condition are determined after the sample suction.

Claims

1. A sample-sucking condition checking method comprising the steps of:

(a) measuring a first suction pressure value P_o at a sampling nozzle, before suction of a sample starts;

(b) starting suction of the sample by driving a sampling pump;

(c) measuring a second suction pressure value P_p at the sampling nozzle when the suction speed of the sampling pump reaches a maximum level during the suction of the sample;

(d) comparing the second suction pressure value P_p with a maximum acceptable pressure value P_H to determine whether or not a clogged condition exists at the sampling nozzle;

(e) stopping the sampling pump if the clogged condition exists at said sampling nozzle;

(f) measuring, if no clogged condition exists at the sampling nozzle, a third suction pressure value P_e at the sampling nozzle when the suction speed of the sampling pump reaches a middle level before the completion of sample-suction; and

(g) comparing a first change between the first suction pressure value P_o and the second suction pressure value P_p with a second change between the first suction pressure value P_o and the third suction pressure value P_e to determine whether or not the sample-suction is normal.

2. The method according to claim 1, wherein the clogged condition includes:

space="preserve" listing-type="equation">P.sub.p >

P.sub.H,

wherein

P_p ;

the second suction pressure value when the suction speed of the sampling pump reaches a maximum level during sample-suction;

P_H ;

the maximum acceptable pressure value during normal suction of the sample.

3. The method according to claim 1, wherein the sample-sucking condition includes:

space="preserve" listing-type="equation">(1) P.sub.L ≦

P.sub.p ≦

P.sub.H and γ

=(P.sub.e -P.sub.o)/(P.sub.p -P.sub.o)>

C for a normal condition; and

space="preserve" listing-type="equation">(2) P.sub.p <

P.sub.L or γ

=(P.sub.e -P.sub.o)/(P.sub.p -P.sub.o)≦

C for a no-sample condition.

where

P_H ;

the maximum acceptable pressure value during normal suction of the sample;

P_L ;

the minimum acceptable pressure value during normal suction of the sample;

P_o ;

the first suction pressure value before start of sample-suction;

P_e ;

the third suction pressure value when the suction speed of the sampling pump reaches a middle level before the completion of sample-suction;

P_p ;

the second suction pressure value when the suction speed of the sampling pump reaches a maximum level during sample-suction;

C;

a determination value obtained experimentally.

4. The method according to claim 1, wherein a latch timing at the first, second and third suction pressure values is determined by measuring periods of time from the start of sample-suction.

5. The method according to claim 1, wherein the determination of whether or not the clogged condition exists is performed by detecting a plurality of second suction pressure values during the sample-suction.

6. A sample-sucking condition checking system comprising:

sampling nozzle to be immersed into a sample;

sampling pump connected to the sampling nozzle through a tube for sucking the sample;

pressure sensing means for measuring a first suction pressure value P_o at the sampling nozzle before suction of the sample starts, a second suction pressure value P_p at the sampling nozzle when the suction speed of the sampling pump reaches a maximum level during the suction of the sample, and a third suction pressure value P_e at the sampling nozzle when the suction speed of the sampling pump reaches a middle level before completion of suction of the sample; and

comparing means for comparing a first change between the first suction pressure value P_o and the second suction value P_p with a second change between the first suction pressure value P_e and the third suction pressure value P_o to determine whether or not sample-sucking condition is normal.

7. The system according to claim 6, wherein the sample-sucking condition includes:

space="preserve" listing-type="equation">(1) P.sub.L ≦

P.sub.p ≦

P.sub.H and γ

=(P.sub.e -P.sub.o)/(P.sub.p -P.sub.o)>

C for a normal condition; and

space="preserve" listing-type="equation">(2) P.sub.p <

P.sub.L or γ

=(P.sub.e -P.sub.o)/(P.sub.p -P.sub.o)≦

C for a no-sample condition.

space="preserve" listing-type="equation">(3) P.sub.p ≧

P.sub.H

for a clogged condition,

where

P_H ;

the maximum acceptable pressure value during normal suction of the sample;

P_L ;

the minimum acceptable pressure value during normal suction of the sample;

P_o ;

the first suction pressure value before start of sample-suction;

P_e ;

the third suction pressure value when the suction speed of the sampling pump reaches a middle level before the completion of sample-suction;

P_p ;

the second suction pressure value when the suction speed of the sampling pump reaches a maximum level during sample-suction;

C;

a determination value obtained experimentally.

8. The system according to claim 6, wherein the pressure sensing means includes microcomputer means for determining a latch timing at the first, second and third suction pressure values by measuring periods of time from the start of sample-suction.