TUBE CLAMPING ARRANGEMENT FOR A DIALYSIS MACHINE

Abstract

The present invention relates to a detection arrangement, comprising: an actuation element, which is designed to be moved back and forth between at least one first and one second position; a fastening portion, which is designed such that the actuation element can be brought into contact with a tube; a spring element, which interacts with the actuation element such that the spring element exerts a force on the actuation element in the direction of the second position; a retaining element, which interacts with the actuation element such that the actuation element can be moved into the first position by means of the retaining element; and a control element, which is designed to detect at least one parameter of the actuation element and/or of the retaining element and evaluate same so that the control element, on the basis of this evaluation, provides information about the condition of the detection arrangement.

Claims

1. A detection arrangement comprising an actuation element that is configured to be moved to and fro between a first position and a second position; a fastening section that is configured such that the actuation element can be brought into contact with a tube a spring element that cooperates with the actuation element such that the spring element exerts a force on the actuation element toward the second position; a retaining element that cooperates with the actuation element such that the actuation element can be moved into the first position by means of the retaining element; and a control element that is configured to detect at least one parameter of the actuation element and/or of the retaining element and to evaluate it such that the control element provides information relating to the state of the detection arrangement on the basis of said evaluation.

2. A detection arrangement in accordance with claim 1, wherein the actuation element can be configured as a clamp and the first position can be an open position of the clamp and the second position can be a closed position of the clamp; and wherein the fastening section can be configured as a reception region for a tube.

3. A detection arrangement in accordance with claim 1, wherein the actuation element is configured as a probe finger.

4. A detection arrangement in accordance with claim 1, characterized in that the spring element is a magnet, in particular a permanent magnet, an electromagnet, or a polymagnet.

5. A detection arrangement in accordance with claim 1, characterized in that the spring element has a non-linear force/distance progression.

6. A detection arrangement in accordance with claim 1, characterized in that the control element is configured to activate the retaining element during a movement of the actuation element in the direction of the second position to move the actuation element in the direction of the first position.

7. A detection arrangement in accordance with claim 1, characterized in that the retaining element is a spring, in particular a tension spring or a compression spring, and/or an electric motor, in particular a stepper motor.

8. A detection arrangement in accordance with claim 1, characterized in that a sensor for determining the position of the actuation element or of the probe finger or of the clamp is present.

9. A detection arrangement in accordance with claim 1, characterized in that the parameter is the position of the actuation element or of the probe finger or of the clamp over the time; and/or in that the parameter is the starting current and/or the current progression over the time of the retaining element.

10. A detection arrangement in accordance with claim 1, characterized in that the control element is configured to control the retaining element such that the retaining element moves the actuation element into the first position or in the direction of the first position.

11. A detection arrangement in accordance with claim 10, characterized in that the control element is configured to control the retaining element such that the actuation element is moved partially or completely into the second position and then partially or completely into the first position.

12. A detection arrangement in accordance with claim 11, characterized in that the control element is configured to carry out the partial or complete movement of the actuation element in the direction of the first position and in the direction of the second position repeatedly at the same frequency or at at least two different frequencies and/or with a frequency sweep.

13. A dialysis machine that is configured to be equipped with a tube system comprising at least one blood tube or that is equipped with such a tube system, wherein the dialysis machine has at least one detection arrangement in accordance with claim 1.

14. Use of a detection arrangement in accordance with claim 1 in a dialysis machine.

15. A method of operating a detection arrangement in accordance with claim 1 for determining the presence of a tube and/or the tube content.

Description

[0079] There are shown:

[0080] FIG. 1: the time progression of the position of the clamp from closed to open and then to the partially closed state;

[0081] FIG. 2: the time progression of the power consumption of the retaining element, with the different times T in accordance with FIG. 1 corresponding to those in accordance with FIG. 2;

[0082] FIG. 3: shows an exemplary force/distance progression of a polymagnet in comparison with an alternative spring element;

[0083] FIG. 4: a schematic design of an exemplary clamping arrangement;

[0084] FIG. 5: an exemplary relationship between the control signal and the reaching of a specific power value; and

[0085] FIG. 6: an exemplary progression of the viscosity of blood over the treatment duration.

[0086] FIG. 1 shows the distance or the position of the clamp blade, i.e. the gripping edge of the clamp over time starting from the closed position W of the clamp.

[0087] The time progressions of the position of the clamp blade are shown for three different situations in FIG. 1. FIG. 1 shows the following three variants: A is the time progression without a tube in the clamp; B is the time progression with an air-filled tube in the clamp; and C is the time progression with a liquid-filled tube in the clamp.

[0088] FIG. 2 shows the time progression of the power consumption of the stepper motor, i.e. of the retaining element.

[0089] FIG. 2 only shows the variants “Tube inserted” and “No tube inserted”.

[0090] Starting from the coordinate origin, the clamp initially remains closed. The retaining element in the form of a stepper motor is currentless. The closed state S is reached and ensured by a polymagnet. The polymagnet or another spring element is arranged such that the clamp is moved into or held in the closed position by the polymagnet or by the spring element.

[0091] The stepper motor is supplied with power at the time T.sub.1. The stepper motor exerts a force on the clamp acting in the open position O. This force acts against the force applied by the spring element. The clamp opens, as can be seen from FIG. 1. The clamp has reached its open position at the time T.sub.oprn.

[0092] FIG. 2 shows the progression of the power consumption of the retaining element over time and illustrates that a starting current is initially required (between T.sub.1 and T.sub.open) to open the clamp. From the time T.sub.open to T.sub.2 onward, a retaining force is sufficient to hold the clamp in its open state. In particular the dependence of the required power consumption on the position of the clamp is illustrated in FIG. 2. Here, the power value I.sub.A shows the value required for the maintenance of the open position; I.sub.B illustrates the power value that is required to open the clamp when the clamp was not fully closed; and I.sub.C illustrates the power value that is required to open the clamp when the clamp was fully closed.

[0093] It further results from FIG. 2 that both the starting current between T.sub.1 a T.sub.open and the retaining current that is needed to hold the clamp open is identical or largely identical for the variants “Tube inserted” and “No tube inserted”. This is due to the fact that the clamp is opened from its completely closed state and is then held in the open position in both cases, i.e. in all three cases, the position of the clamp (first in the closed position and then in the open position) is identical so that the retaining device has to perform the same work to open the clamp and hold it in this position.

[0094] The current of the stepper motor is deactivated at the time T.sub.2, which has the result that the clamp starts to close due to the force of the spring element.

[0095] FIGS. 1 and 2 schematically show the progressions of the position of the clamp and the power consumption of the stepper motor for the three above-named variants from the time T.sub.2 onward. The distance between the progressions of the three variants first increase and then decreases, as can in particular be seen from FIG. 1.

[0096] If the progression in accordance with FIG. 1 is measured using a Hall sensor or the like, it can be determined from the absolute value of the distance S at a specific point in time or from the time progression of S over T or from a comparison of the absolute value or of the progression with a reference value whether no tube is inserted in the clamp or whether a tube has been inserted in the clamp and whether it is filled with air or with blood. The clamp is closed the most in the variant without a tube at a specific time T.sub.z since no tube counteracts the closing movement. The blood filled tube is closed the least; the distance for the air filled tube is therebetween. If the absolute position of the clamp or of the time progression is measured, a statement can be made on which variant is present without any measurement of the power consumption.

[0097] Alternatively, in a further embodiment that manages without a sensor, the position of the clamp can equally be detected.

[0098] A preferred embodiment comprises the starting current of the anyway required retaining element, in particular of the stepper motor, being used to check which of the variants is present. As can be seen from FIG. 2, the retaining element has power applied at the time T.sub.z so that the clamp opens again from this time onward, which is not shown in FIG. 1. FIG. 1 schematically illustrates the different time progressions of the variants during the closing procedure, that is the distance covered by the clamp over the time. FIG. 2 shows the starting current resulting from the different progressions on an interruption of the closing procedure at T.sub.z.

[0099] The starting current differs both in its maximum value and in its progression, as can be seen from FIG. 2. It results from FIG. 2 that both the maximum value of the starting current and the area under the progression of the current over the time is greater for the case that no tube is inserted than for the case that a hose is inserted.

[0100] This is due to the fact that the clamp without a tube has to cover a further distance at the closing procedure starting at the time T.sub.z and has to overcome a greater force of the spring element than is a tube is inserted. It can thus be determined from the absolute value of the starting current and from the integral below the progression of the starting current over the time whether a tube is located in the reception region of the clamp or not.

[0101] The above-described closing and opening procedures of the clamp can be carried out once or multiple times. On a multiple opening and closing, the frequency can be set in a suitable manner. In FIG. 1, three frequencies are indicated at which the above-named procedure of the partial closing and opening of the clamp is carried out. The frequency here is f1 > f 2 > f3.

[0102] FIG. 3 shows an exemplary force/distance progression of a polymagnet in comparison with an alternative spring element having a linear force/distance progression. A conclusion on the position of the clamp can be drawn from the required starting current due to the non-linear force/distance progression.

[0103] FIG. 4 shows a schematic design of an exemplary clamping arrangement. The left side here shows the clamping arrangement in a closed position while the right side shows the clamping arrangement in an open position. The retaining element is shown schematically by an electric motor 1. The spring element 3a, 3b is shown as a polymagnet, with the upper element of the polymagnet being the element rotatable by the electric motor and with the lower element of the polymagnet being the element displaced in the z direction on a rotation of the upper element. The clamp is shifted between the open and closed positions by the displacement of the lower element of the polymagnet. In the closed position shown on the left side, the movable element of the clamp is shifted upward and can clamp a tube closed in this position.

[0104] An exemplary relationship between the control signal and the reaching of a specific current value is shown in FIG. 5. The frequency here can, as shown in FIG. 5, be set as so small that a distance change at the clamp cannot yet be measured or can only be unnoticeably measured.

[0105] FIG. 6 shows by way of example the progression of the viscosity of the blood over the progression of a treatment time. The viscosity here increases with the time, with the water content in the blood decreasing over the treatment time.