Blood collecting apparatus

• US 5,403,279 A
• Filed: 05/10/1994
• Issued: 04/04/1995
• Est. Priority Date: 06/29/1988
• Status: Expired due to Term

• Current Assignee: Terumo Kabushiki Kaisha (Terumo Corporation)
• Original Assignee: Terumo Kabushiki Kaisha (Terumo Corporation)
• Inventors: Inoue, Satoshi, Inaba, Fumiaki
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US08/240,493
• Time in Patent Office: 329 Days
• Field of Search: 604/4, 604/65, 604/67, 604/245, 604/403, 604/903, 128/770, 128/771
• US Class Current: 604/65
• CPC Class Codes: A61M 1/0245 combined with blood container shaking means

Abstract

A blood collecting apparatus includes a measuring device provided with a sensor for measuring the amount of collected blood when blood is collected into a blood container, and a controller for calculating the amount of collected blood based on an output y of the measuring sensor. The output y is a function of an n-times measured weight w of collected blood such that y=aw+b, wherein a and b are constants characteristic of the measuring sensor. The controller detects the output yi of the measuring sensor in n+1 units of respective known amounts wi of collected blood, and corrects the constants a and b on the basis of such detected data. The controller, moreover, automatically detects the output yO of the measuring sensor every predetermined cycle in a state where the measured weight w of collected blood is zero, and corrects the constant b of the function y=aw+b on the basis of such detected output yO.

Claims

1. A blood collecting apparatus (10), comprising:

a blood collecting chamber (13);

a blood container (1) received in said blood collecting chamber (13);

means for evacuating air from said blood collecting chamber (13) to generate a negative pressure in said blood collecting chamber (13), to thereby form a blood collecting evacuated chamber (13);

weight measuring means including a weight measuring sensor (33) for generating an output signal y corresponding to a weight w of blood collected in said blood container (1);

control means (65) for calculating the amount of collected blood in said blood container (1) based on the output signal y of said weight measuring sensor (33) being in a given relationship with the measured weight w of the collected blood, which is expressed as a function y=f(w), where f(w) comprises at least one constant value (a, b),

said control means (65) including memory means (66) for storing specific values of said at least one constant (a, b) of the function y=f(w) of said weight measuring sensor (33);

means for setting said control means (65) in a correction mode, before starting blood collection or after completion of blood collection in said blood container, and wherein in the correction mode, said weight measuring sensor (33) senses the weight of n samples, where n is an integer of 2 or more, of known weight and said output signal of said weight measuring sensor is coupled to said control means which calculates the known weight based on said function y=f(w) and corrects said at least one constant value (a, b) of said function y=f(w) if the calculated weight is not the same as said known weight, and said control means automatically rewrites the corrected value of said at least one constant value in said memory means (66), thus correcting the measuring characteristic of said weight measuring sensor (33);

said control means (65) thereafter calculating the weight, of the collected blood based on said output signal y, said function y=f(w), and said corrected values of said at least one constant value (a, b);

means for taking out an output signal y of said weight measuring sensor (33) at predetermined intervals when a measured weight w of collected blood is zero, and wherein an off-set value of said function y=f(w) is corrected on the basis of said output signal y taken out of said weight measuring sensor (33) at said predetermined intervals;

a pressure measuring means including a pressure measuring sensor (73) for detecting the pressure in the blood collecting evacuated chamber (13) and for generating an output z which is a function of the pressure detected by said pressure measuring sensor;

said control means (65) calculating a pressure based on said output z of said pressure measuring sensor (73) being in a given relationship with the measured pressure p, which is expressed as a function z=f(p), where f(p) comprises at least one further constant value (c, d);

said memory means (66) of said control means (65) storing specific values of said at least one further constant value (c, d) of the function f(p) of said pressure measuring sensor (73); and

wherein when said control means is in said correction mode, said pressure measuring sensor (73) senses the pressure of n known pressure amounts, where n is an integer of 2 or more, and said output signal z of said pressure measuring means is coupled to said control means (65) for calculating the known pressure based on said function z=f(p) and correcting said at least one further constant value (c, d) of said function z=f(p) if the calculated pressure is not the same as said known pressure, and said control means automatically rewrites the corrected value of said at least one further constant value in said memory means (66), thus correcting the measuring characteristic of said pressure measuring sensor.

2. The blood collecting apparatus of claim 1, wherein said at least one constant value of said function y=f(w) comprises two constant values (a and b).

3. The blood collecting apparatus of claim 2, wherein said at least one further constant value of said function z=f(p) comprises two further constant values (c and d).

4. The blood collecting apparatus of claim 1, wherein said at least one further constant value of said function z=f(p) comprises two further constant values (c and d).