JPH0113048B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a rotatably driven measuring tube, which is held in a predetermined position in the bottom region of the measuring tube and which is rotated by the wall surface of the tube. The spheres are made of fibrin (fibrin).
The core gyrometer is adapted to be entrained by the wall of the measuring tube at the time of its formation. A coagulometer is a device that measures blood coagulation function.

Prior Art Such core gyrometers are well known. In such core gyrometers, a glass bulb is located in the measuring tube, which is supported in a steeply inclined manner and is driven in rotation, in comparison with the radius of curvature at which the measuring tube wall transitions into the measuring tube bottom. The sphere is held in place in the bottom region of the measuring tube by gravity due to the inclined state of the measuring tube. In this case, the glass bulb is usually rotated in its position due to the rotation of the measuring tube.
Now, when the blood begins to coagulate and the formation of fibrin or fibrin begins, the fibrin adheres to the walls of the glass bulb and the measuring tube, so that the glass bulb is carried away from its position by the measuring tube during its rotation. becomes. Therefore, a change in the position of the glass bulb occurs,
The operator can visually confirm the change in position. Based on this, for example, a time measuring device or a similar recording device, which was switched on at the beginning of the measurement, is switched off. Such a measurement method is generally referred to as the "ball method" and is well known.

It is not possible with a coagulometer of the type described above to automatically record the onset of coagulation and thereby automatically determine the coagulation time of a given sample introduced into the measuring tube. Because the first
Second, the entrained movement of the glass bulb is relatively uncertain, and secondly, in such an arrangement, the glass bulb will quickly shift due to its own weight to the center of the bottom of the measuring tube, even if it is visually discernible. This is because it often occurs that the ball undergoes very little displacement movement which cannot be recorded automatically and reliably enough. A further disadvantage of this configuration is that only clear plasma samples can be processed due to the need for visual detection. When using poorly defined plasma samples or pure blood, the moving movement of the sphere cannot be detected visually with sufficient certainty.

Furthermore, a steel ball is placed in a measuring tube that moves up and down,
Core gyrometers are known in which this steel ball is held stationary relative to a moving tube by means of two mutually opposing magnets. In this core gyrometer, a sensor device consisting of a lamp and a photocell is arranged in the vertical axis direction. Usually the measuring tubule is
Performs relative motion to the ball held by a magnet. Once the formation of fibrin begins with the onset of solidification, the entrainment of the steel ball by the up-and-down measuring tube also begins. As a result, the steel ball disappears from in front of the photocell, the light of the lamp reaches the photocell and a control pulse is formed which can be used to stop the previously activated counting device.

Such a core gyrometer has a complicated structure and is expensive to manufacture. In any case, two systems are required for the sphere. That is, a holding system using a magnet and an optical detection system that triggers a control signal. The steel ball and the wall of the measuring tube must be manufactured with high precision to ensure reliable entrainment. In addition, it is costly to force the measuring tube to move up and down. Therefore, in order to make it more cost-effective, a motor for driving an eccentric cam is provided below the measuring tube. The eccentric cam periodically lifts the measuring tube guided into the mounting hole, and the measuring tube lowers again under its own weight. However, such a device is sensitive to disturbances, and depending on the weight of the measuring tube, it may not descend quickly, only partially, or may descend very slowly. First of all, this is because the holes are not particularly protected and there is a risk of dust adhering to them. Therefore, the movement of the steel ball is automatically recorded, but the recording is unreliable given the high cost of the equipment configuration. Even in this case, only substantially clear plasma samples can be used with the optical detection device, and not blurred plasma samples or pure blood samples.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a core gyrometer which has a simple construction and which reliably and reliably performs automatic detection of the onset of coagulation.

Means for Solving the Problem The above problem is achieved by configuring the travel path of the ball in the bottom area of the measuring tube as follows, and assigning the restriction pin 4 concentrically protruding from the bottom 3 to the travel path as follows. It is solved by forcing people to do something. That is, the sphere 5 is constructed and attached in such a way that it has only a small distance from the area corresponding to the sphere of the limiting pin 4 and from the area corresponding to the sphere of the wall surface 2 of the measuring tube, and furthermore, the sphere The solution is to provide a sensor 9 in the travel path along which the ball 5 moves, which triggers a control pulse in response to the sphere.

With the above configuration, at the start of coagulation, the fibrin matrix is formed not only between the sphere and the travel path area of the sphere, but also between the sphere and the measurement tubule area corresponding to the sphere, and between the spheres and the restriction corresponding to the sphere. It also comes to be formed between the opposing region of the pin. In this case, the limit pin prevents the ball from shifting into the center of the bottom of the tube due to its own weight as it is carried along by the rotating measuring tube. This configuration ensures that the spheres are reliably entrained at the beginning of coagulation and
It was found that the ball accurately passes through the predetermined path of travel in the entrainment phase. This position change of the sphere can then be recorded automatically and correspondingly reliably by a sensor that triggers a control pulse. This type of core gyrometer has a very simple configuration. Only a rotational drive mechanism for the measuring tube is required. In this case, it is furthermore advantageous to hold the sphere in position in the bottom region of the measuring tube at the beginning of the measuring phase by simple known means. It is thus advantageous to provide the measuring tube in an inclined position and to hold the sphere in position by gravity.

Advantageous embodiments of the core gyrometer according to the invention are set out in the patent claims.

By using a groove as claimed in claim 2, it is ensured that the ball is substantially always in only point contact with the measuring tube at the beginning of the measuring phase. Therefore, there is no tendency for the ball to be carried away prematurely in this phase, and especially for the ball to spin or swing.

Furthermore, it has been found that if a recess is provided in the region of the limiting pin and the wall of the measuring tube close to the sphere, a particularly reliable entrainment of the sphere can be determined very precisely in time.

It is also advantageous to use a magnetic sensor and to form the sphere from a ferromagnetic material. This makes it possible to test not only clear plasma samples, but also non-clear plasma samples and pure blood samples, making this type of coagulometer particularly applicable to a wide range of fields.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The measuring tube 1 of the core gyrometer shown in FIGS. 1 and 2 has a substantially cylindrical side wall 2 . This side wall surface has a slightly thinner material as it goes upwards and is bent at a right angle to form the bottom 3 of the measuring tube. The respective circular edges of the measuring tubes are indicated by a, b, c, d, and the angular portions of the web 8 are indicated by x, y to clarify the correspondence between FIGS. 1 and 2.

A conically tapered limiting pin 4 projects upwardly from the bottom 3 concentrically with respect to the central longitudinal axis of the tubule.
Furthermore, the bottom part 3 defines a ball travel path for the steel ball 5 placed in the small tube (see FIG. 2). This ball traveling path is defined by the groove 6. The groove 6 is formed in the bottom and has a radius of curvature slightly larger than the radius of the sphere 5. With such a configuration, the ball 5 essentially makes point contact within the groove 6.

As can be seen in FIGS. 1 and 2, the limiting pin 4 is provided with a plurality of small webs 7 spaced apart from each other and parallel to the longitudinal axis of the measuring tube, so that the limiting pin 4 can be The cylinder has a recess. The side wall surface 2 of the measuring tube is also provided with a recess in its lower part, in the region co-operating with the sphere 5, with small webs 8, which are likewise spaced apart from each other and parallel to the longitudinal axis of the measuring tube. is forming. This web 8 ends at the bottom 3 with a radius of curvature, so that it is not completely closed in FIG. The webs 7 and 8 are only so far apart that they cannot come into contact with the ball 5 located in the groove 6, at least during the normal operating phase. The dimensions of the arrangement of the grooves 6 and the dimensions of the balls and the webs are such that the balls 5, in normal phase, have only a small distance from the respective opposing areas of the webs 7 and 8, respectively.

In this case, in contrast to the side wall surface 2, the web 8 of the side wall surface is designed to extend into the groove 6 by itself with a radius of curvature corresponding to the radius of curvature of the groove 6. Further, the webs 7 and 8 are constructed so that both their height and width become slightly narrower toward the top.

The core gyrometer has a dry incubator (not shown) in which a measuring tube is rotatably supported at a slight inclination of approximately 10°. This tilted state is shown in FIGS. 2 and 4. The measuring tube 1 is slowly rotated about its longitudinal axis by a rotary drive mechanism. To determine the clotting time, ie the onset of formation of a fibrin matrix in the clotted precipitate, the clotted precipitate, which consists of clear plasma, dull plasma or pure blood, for example, is introduced into a measuring tube. Due to the inclination of the measuring tube, the steel ball 5 is held in a defined position relative to the measuring tube 1. Since the steel ball 5 is in point contact with the rotating measuring tube, it also rotates, but due to its own weight, it normally remains at a predetermined spatial position. Once solidification begins, the narrow space between the steel ball 5 on the one hand and the free part of the groove 6 on the other hand, for example, the side wall surface 2 and the limiting pin 4, and also, apart from this, for example the corresponding web regions 7 and 8.
Immediately in the narrow space between, a fibrin matrix is formed which is better adhered to webs 7 and 8. This results in a reliable and time-exactly defined entrainment of the steel ball 5 by the measuring tube 1. That is, the steel ball 5 now follows a rotational movement towards the measuring tube and thus first leaves the predetermined position shown in solid lines in FIG.
In the exemplary embodiment, this precisely defined position change is detected by a magnetic sensor 9 which is arranged adjacent to the outer cylindrical part of the measuring tube 1 and in the area of the path along which the steel ball 5 travels in the entrainment phase. This magnetic sensor triggers a control pulse to stop the coagulation time recording device that was previously activated when the coagulation precipitate was introduced.

The magnetic sensor 9 used in the example is shown in FIG. 3 together with its control circuit. The magnetic sensor used here has an integrated Hall effect element and is configured to proportionally convert changes in magnetic flux density into changes in voltage, producing an output voltage that increases positively as magnetic flux density increases. Occur. A magnetic sensor using this type of Hall effect element does not have hysteresis characteristics, so it can be regarded as a linear converter. A permanent magnet is provided on the back side of the sensor chip. This permanent magnet generates an inductive bias that ensures that changes in magnetic flux density occur only due to the proximity of magnetic material. This type of change in magnetic flux density occurs along the sensor chip. This is because the permanent magnet on the back side of the sensor chip and the magnetic material passing in front of it on the front side are responsible for the magnetic flux changes. Passive used to suppress noise effects
Sensor 9 via RC-low pass filter 11
The signal sent from the first operational amplifier 1 is capacitively
2 reaches the non-inverting input side. In particular, this first operational amplifier is connected in such a way that its inverting input is supplied with a portion of the output voltage of the operational amplifier via a resistor-resistor circuit, one resistor being adjustable. This variable resistor is at the same time bridged by a capacitor. The amplification factor of the operational amplifier 12 is determined in this case by the set ratio of the two resistance values. The bridging capacitor C automatically reduces this set ratio, or amplification factor, as the frequency increases. Signals with high voltage change rates, which often cause disturbances, are thereby completely eliminated and do not have any influence on the measurements.

The signal obtained at the output side of the operational amplifier 12 in this way is sufficiently amplified and then sent to the second operational amplifier 1.
3. This operational amplifier operates as a voltage comparator with hysteresis characteristics.
The hysteresis characteristic prevents continuous switching. This circuit is constructed as follows. That is, a voltage of, for example, half the supply voltage is applied to the inverting input of the operational amplifier 13 via two resistors in the form of a voltage divider, so that the operational amplifier 13 is switched from the first operational amplifier 12 to the operational amplifier 13. The circuit is configured to deliver a pulse when the voltage applied to the non-inverting input of the circuit exceeds half of the supply voltage. This pulse is used as a stop signal for a recording device (eg, an electronic stopwatch, not shown) that measures clotting time. The process of signal generation is as follows. That is,
During the entrainment phase, the ball 5 first approaches the sensor 9 and passes in front of it, as shown by the dotted line in FIG.
As a result, a half-wave-like signal course occurs. With the described arrangement and the configuration of the second operational amplifier, a precise point in time on the rising edge of said half-wave is detected and a stop signal is sent to the electronic stopwatch.

Furthermore, in order to eliminate the influence of the power supply voltage and to stably maintain the operating point once set, it is advantageous to power the described control circuit, including the sensor, by a voltage stabilizing circuit. At the same time, a constant temperature reference voltage source delivers the reference voltage necessary to adjust the offset voltage of the sensor.

The embodiment described here has a particularly simple design, in which the steel ball 5 is held in position during the first phase of the measurement by gravity and the inclination of the measuring tube. In this special case,
It is also possible to stand the measuring tube vertically and hold the ball in place by a small stop magnet with a certain force. FIG. 4 shows a simplified arrangement of a known core gyrometer for reference.

Effects of the Invention According to the present invention, a core gyrometer is obtained which has a measuring tube in which the balls placed therein are reliably entrained at the onset of blood coagulation, and in which the entrainment of the balls is reliably detected.

[Brief explanation of drawings]

FIG. 1 is a plan view of the measuring tube of the core gyrometer according to the present invention, FIG. 2 is a cross-sectional view of the measuring tube along the - line, and FIG. 3 is a circuit diagram of the magnetic sensor of the core gyrometer according to the present invention and its necessary control unit;
FIG. 4 is an explanatory diagram showing a simplified overall arrangement of a known core gyrometer. 1... Measurement small tube, 2... Side wall surface, 3... Lower part,
4... Limiting pin, 5... Ball, 6... Groove, 7, 8...
...web, 9...magnetic sensor, 10...Hall effect element, 11...RC-low-pass filter, 1
2, 13... operational amplifier, a, b, c, d... each circular edge of the measuring tube, x, y... angled portion of the web 8, 101... measuring block, 102... measuring tube, 103 ...ball, 104...magnetic sensor,
105...Hall effect element.

Claims (1)

[Scope of Claims] 1. comprises a rotatably driven measuring tube and a ball held in a predetermined position in the bottom region of the measuring tube and capable of rotational movement by the wall of the tube;
In core gyurometers, in which the balls are entrained by the wall of the measuring tube at the time of fibrin or fibrin formation, a running path for the balls is provided in the bottom region of the measuring tube; A limit pin 4 is disposed concentrically protruding from the ball 5.
is configured such that it has only a small distance from the area corresponding to the ball of the restriction pin 4 and the area corresponding to the ball on the wall surface 2 of the measuring tube, and furthermore, in the movement path followed by the ball when entrained, Core gyrometer, characterized in that it is provided with a sensor 9 which triggers a control pulse in response to the sphere. 2. The core gyrometer according to claim 1, wherein the ball traveling path is defined by a groove formed in the bottom part 3 of the measuring tube, and the radius of curvature of the groove is slightly larger than the radius of the ball 5. 3. The core gyurometer according to claim 1, wherein the limiting pin 4 and the measuring tube wall 2 are provided with a longitudinal recess in the region closer to the sphere. 4. Core gyrometer according to claim 3, wherein the recess is formed by small webs 7, 8 spaced apart from each other and parallel to the longitudinal axis of the measuring tube. 5 The web 8 provided on the measuring tube wall surface 2 is
The core gyurometer according to claim 4, which enters the groove with a radius of curvature corresponding to the radius of curvature of the groove. 6. The core gyrometer according to claim 1, wherein the sensor is a magnetic sensor 9, and the ball 5 is made of a ferromagnetic material. 7. The core gyrometer according to claim 6, wherein the magnetic sensor 9 is provided with an integrated Hall effect element. 8 The magnetic sensor 9 is controlled by an operational amplifier 12.
, the magnetic sensor sends a signal to the non-inverting input of the operational amplifier, and the magnetic sensor sends a signal to the non-inverting input of the operational amplifier
The inverting input side of 2 is connected to a portion of its output voltage via two resistors, one of which is adjustable and bridged by a capacitor. Claim 6 or 7
Core gillometer as described in section. 9. The core gyrometer according to claim 8, wherein a passive RC low-pass filter 11 is inserted and connected between the output side of the magnetic sensor 9 and the non-inverting input side of the operational amplifier 12. 10. The core gyrometer according to claim 7, wherein a second operational amplifier 13 is connected after the first operational amplifier 12, and the second operational amplifier is connected as a voltage comparator having hysteresis characteristics. .