Apparatus for automatically measuring the viscosity of liquids

• US 4,388,823 A
• Filed: 03/10/1981
• Issued: 06/21/1983
• Est. Priority Date: 03/26/1980
• Status: Expired due to Fees

• Current Assignee: Medica Tekku Kabushiki Kaisha
• Original Assignee: Medica-Test
• Inventors: Garnaud, Guy, Bouhier, Roger
• Primary Examiner(s): Ciarlante, Anthony V.
• Assistant Examiner(s): Carlson, David U.
• Application Number:
  US06/242,387
• Time in Patent Office: 833 Days
• Field of Search: 73/57
• US Class Current: 73/54.18
• CPC Class Codes: G01N 11/12 by measuring rising or falling speed of the body; by measuring penetration of wedged gauges G01N11/16 takes precedence

Abstract

The apparatus for measuring the viscosity of liquids comprises an inclined viscosimetric tube (1) enclosing a ball (3). A device is provided for measuring the duration of fall of the ball (3) in the tube (1). An electromagnet (8) adjacent the tube (1) has poles (9) which set up along the tube (1) a gradient of a magnetic field allowing the automatic rising of the ball (3). The apparatus is used mainly for measuring the viscosity and the time of the coagulation of blood.

Claims

1. Apparatus for automatically measuring the viscosity of liquids, comprising in combination a viscosimetric tube (1), kept in an inclined position and containing a ball (3) made of magnetic material, means (2) for introducing the liquid to be tested in said tube and means for measuring the duration of fall of said ball (3) in the tube (1) containing the liquid, said means being associated with means for converting into viscosity the duration of fall of the ball (3) from the top of the tube, electromagnetic means for applying to said ball a magnetic field so as to maintain said ball at the top of said tube and means for suppressing the magnetic field and allowing the fall of the ball (3) in the tube (1), wherein said electromagnetic means (8) comprise an electromagnet having two poles with their ends (9a) being disposed relative to one another and defining an air gap (10) which is lengthy and narrow, along which the viscosimetric tube (1) is placed, with the distance (d) between said tube and the ends (9a) of the two poles (9) augmenting progressively between the top and the bottom of the tube (1), so as to create along the tube a magnetic field gradient directed towards the top of the tube which permits automatic rising of the ball from the bottom of the tube to the top of the tube when the electromagnet is energized.

2. Apparatus according to claim 1, wherein said electromagnet (8) is associated with control means (14 to 24) allowing automatic and periodic operation of the electromagnet for the purpose of performing repetitive measurements of viscosity, and wherein said control means comprise a first temporization circuit (23, 24) controlling the stopping of operation of the electromagnet (8) during a controllable and adequate period for allowing the measurement of the duration of fall of the ball (3), and a second temporization circuit (14 to 18) which controls by means of a relay (19) the energizing of the electromagnet (8) during an adequate period for allowing the rising of the ball in the viscosimetric tube (1).

3. Apparatus according to claim 1 wherein said poles (9) have near their ends (9a) a transverse, triangular section, with the ends (9a) of said poles being rectilinear and forming between them an angle (a) substantially between 0°

and 20°

, the minimal distance between the ends (9a) being smaller than the diameter of the tube (1) and the latter forming with a plane (P) parallel to the two rectilinear ends (9a) of the poles (9) an angle (b) between 5° and

20°

.

4. Apparatus according to claim 3, wherein said air gap (10) defined between the poles (9) of the electromagnet (8) has a length which is substantially equal to the height of the fall of the ball (3).