DE2543185A1 - Peristaltic pump with delivery control unit - has timing cycle generator connected in series to preselection and control units for cyclic delivery - Google Patents

Abstract

Peristaltic pump designed partic. for precise delivery of amounts of infusion whose quantities are chosen in relation to e.g. the absorption capacity of the patient, and the type of infusion medium. A timing cycle generator for producing predetermined timing impulses ins connected in series with a preselection unit and a control unit for preselecting the quantity delivered per unit time. A detector produces test impulses depending on the amount of the medium conveyed by the pump whereby a monostable trigger circuit prevents a double counting of the amount of medium. A current circuit receives the test and quantity representing impulses and, depending on a comparison made between the impulses, produces a signal for controlling a motor which drives the pump. A programmable alarm is actuated should the amount of medium conveyed per unit time be too small or too large.

Description

Device for controlling and regulating the delivery rate of a medium a peristaltic pump The invention relates to a device for controlling and Control of the flow rate of a medium within a unit of time with a peristaltic pump.

In peristaltic pumps or infusion devices, there is a need to generate the number of drops as a function of time in a medium, e.g. a liquid such as blood, remedies, food, saline and other infusion therapy preparations, and to deliver it intravenously into the patient . Determining the amount of a patient to be infused depends on their metabolism, absorbency and the infusion It is therefore absolutely necessary to convey the amount of infusion with great precision and to regulate it to the specified value or to control it to new values during the infusion process.

The known infusion devices can have the predetermined number the drop in a unit of time, e.g. per second or per minute, do not comply and are not able to guarantee that the drops fall absolutely regularly.

This disadvantage is particularly noticeable with different Solutions of the lines or tubes leading to the infusion medium, which also have different diameters (clear widths). As a result of the technical Inadequacy of the infusion devices and the tubes or lines, which bring the infusion medium to the actual pump, the drop size changes of the infusion medium in an uncontrolled manner. The respective viscosity of the infusion medium is not even taken into account here, so that another factor of uncertainty is available for the exact adherence to the infusion amount required for the patient can even be lifesaving. Therefore, the known infusion devices are continuously monitored and readjusted by the nursing staff.

It is well known that every manipulation of the nursing staff involves dependency his level of training and his attitude to work a more or less big source of error in itself.

The object of the invention is to design a control and regulating device, which is independent of the technical and human inadequacies.

The invention aims at a precise promotion of the amount of infusion with the values due to the determination of the metabolism, the patient's ability to absorb and of the infusion medium are given, the Dimensions of the tubes and the manipulation of the nursing staff during the infusion process cannot result in any unintentional changes in the amount of infusion.

The invention is characterized by: - a clock for Generation of predetermined time pulses with a preselection device for preselecting the Delivery rate per unit of time and with a circuit to avoid changes the equidistance between two pulses representing the delivery rate; - a Detector for generating measuring pulses depending on the one supplied to the pump Amount of the medium, with means provided to avoid duplication Counting the amount of medium; - a circuit that represents the flow rate Pulses and receives the measuring pulses and in dependence of comparison between the pulses a signal is generated to control a motor for the drive the pump; - a programmable alarm device for giving an alarm if the or Too great a flow rate of the medium per unit of time.

An exemplary embodiment of the invention is based on the drawings explained in more detail. 1 shows the entire control circuit in a block diagram; FIG. 2 shows a modified exemplary embodiment for part of the control system of FIG. 1; 3 shows a graphic illustration to explain the mode of operation of a component the control system of FIG. 1.

In Fig. 1, a reduction stage 1 is used as a clock generator, which is connected to the normal power supply network via the transformer T. The power supply network can have a frequency of 50 Hz or 60 Hz. If those Should have a reduction ratio of 3: 1, every 60 Milliseconds a pulse is generated, which is transmitted via line 111 to the downstream Preselection device 2 is given. This preselection device can in the embodiment as Frequency multiplier be formed, which through the input 21 on the line 22 is controlled.

In input 21, which can be designed as a decade switch, the desired number of drops per unit of time is set. E.g. can 1 to 99 drops per minute can be set. The preselector 2 sends the pulses to the downstream circuit on its output line 23 3, in which care is taken that they have the same time intervals between them exhibit. If this is not the case, these equidistance will be between corrected according to the impulses. These corrected impulses correspond to the preselected number of drops per unit of time. The time unit can be seconds, minutes or hour. These corrected pulses reach one via line 31 Converter 4, which in this embodiment is designed as a differentiating element is. This converter differentiates the rising edges of the incoming pulses and gives this differentiation over the line; 42 on the circuit 5. In the same In this way, the falling edges of the pulses can also be differentiated.

The differentiation of an edge of the incoming pulses is therefore made to prevent in the comparison circuit 5 at the same time Pulses can reach the lines 42 and 43. Instead of the differentiators 4 and 41, the components of FIG. 2 can also be used, resulting in a will be explained in more detail later.

The infusion device or peristaltic pump 12 is on the tube or cutlery 61 is connected to a vessel (not shown) from which the infusion liquid flows drop by drop into the drop chamber 6. With the exit of the drop chamber 6 the hose or the cutlery 62 is connected. This cutlery 62 is from the eccentric shaft 121 the Influences peristaltic pump or infusion device 12, so that the liquid, which is located in the cutlery 62, in peristalsis movements is moved further and is thus conveyed to the end 63 of the cutlery 62. At this At the end 63, for example, an infusion needle can be connected, which carries the infusion liquid gives intravenous to the patient. The cutlery 62 is between the eccentric shaft 121, which consists of several individual parts 122, and a plate-shaped element 64 arranged so that the peristalsis movements are caused by the movements of the eccentric shaft 121 can take place in the cutlery 62.

Around the drop chamber 6 is a double photoelectric scanning device 7 arranged. This dual arrangement ensures that every drop is properly handled is detected regardless of the respective shape of the drop chamber 6 (cutlery with grooves) and the manipulations of the nursing staff. As is well known, it is Nursing staff are not technically trained and therefore cannot convince themselves whether a correctly shaped drop chamber 6 is also correctly in front of the scanning device 7 is arranged because an infusion process is carried out quickly and medically correctly has to be, so that unfortunately there is no time for such technical matters is. In order to avoid such errors, the double probe device 7 is used intended.

This scanning device is each a gallium arsenide diode 71, which emits its light beam onto a phototransistor 72 made of silicon. the Both light bundles are arranged in such a way that they are in the drop chamber 6th do not cross. With each passage of a drop from the cutlery 61 into the drop chamber 6, the photoelectric scanning device 7 generates and outputs a pulse via line 73 to a monostable tilting circuit 8. This tilting circuit prevents that a pulse is counted twice, for example. Such a miscalculation is caused by it avoided that the first mentioned correct drop impulse the monostable tilting circle 8 tilts into its unstable state, in which it remains e.g. 10 milliseconds, to then return to its stable state. During the unstable State have pulses that the scanning device 7 via line 73 to the monostable Apply multivibrator 8, no influence whatsoever. This ensures that each drop in the drop chamber 6 also generates only one pulse. Each of these Droplet impulse arrives via line 81 to a converter 41, in which either the rising edge or the falling edge of the pulses can be differentiated. the Differentiated pulse edges reach the comparison circuit via line 43 5.

At this point I would like to briefly mention the importance of the two converter stages 4 and 41 received, which are designed as differentiators. Because the flanks the TARGET impulses of the lines 42 and the ACTUAL impulses of the line 43 are differentiated it is impossible for the two types of pulses to be in the Comparison circuit 5 arrive. Such a measure is necessary because im Embodiment of the comparison circuit 5 is designed as a buffer counter. The TARGET impulses of the line 42, which the desired number of drops per unit of time are counted into the buffer counter 5 in one direction. The ACTUAL impulses, which indicate the effective number of drops per unit of time, are counted via line 43 in the buffer memory 5 in the other direction, so that the SoLL pulses of the line 42 are added and the ACTUAL pulses of the line 43 can be subtracted from the NOMINAL pulses. Such a scheme is shown in FIG shown. It is assumed that the DESIRED pulses on line 42 in additive Direction in the buffer counter 5 are counted. That means that the target impulses of the line 42 result in a positive counter reading, e.g. at the counter reading +1 control device 10 is activated via line 51, so that via line 101 the motor 11 of the pump 12 can start. Assume now that a drop has fallen from the area 61 into the drop chamber 6 and that this drop has passed through the detector 7 was detected. The ACTUAL pulse passes through the elements 8, 41 through the line 43 into the buffer counter 5 and reduces the count + 1 to the counter reading 0. The motor 11 is switched off again immediately. In other words said, in the direction of patient 63, there is an equivalent amount of the infusion fluid been promoted. If now 3 target impulses, i.e. 3 drops per time unit over the Line 42 are entered into the buffer counter 5, so is the status of the counter +3. The motor 11 rotates and moves the pump 12 until 3 drops, i.e. 3 actual pulses have set the counter 5 to the value 0 via the line 43. In Fig. 3 is the Rotation range of the motor denoted by M. Let us now assume that there are too many Drops fall from the cutlery 61 into the droplet chamber 6. This is straightforward the case when the cutlery 61 has an inside diameter that is too small or when that The capillarity of the infusion liquid is too small. In this case you can e.g.

several drops fall one after the other into the drop chamber, which causes the Scanning device 7 detected according to regulations.

Via the line 43, the corresponding ACTUAL pulses reach the Buffer counter 5 and bring it to the counter reading of -7, for example. The engine 11 is not in action, so no infusion fluid is currently heading Patient can be transported. Only when the prescribed nominal impulses, which represent the number of drops per unit of time, via line 42 in the When buffer counter 5 is reached, its target value changes e.g. from -7 to the value 0. The However, motor 11 is only put into operation when the counter reading is restored gets to +1. At this point, however, it should be noted that according to Fig. 3 a dashed line is drawn at counter reading -2. This dashed Line is a value that when exceeded in the control unit via one of the lines 51 - 52 a special manipulation is carried out. The case has just been described that the counter reading of the buffer counter went beyond this point -2 in the direction -7. When this is exceeded in this direction, a is not in control unit 10 The specially shown circuit is activated at the next start of Motor 11 has a reduced speed compared to the previous and normal Programmed speed.

If now, as already mentioned, the counter reading has reached + 1, so the motor 11 starts via the control device 10 only at a reduced speed. This avoids that too many drops from the cutlery 61 in the drop chamber 6 can fall. This self-regulating effect makes the entire Infusion device made independent of the geometric dimensions of the cutlery 61 and the capillarity of the infusion liquid currently used.

The amount that is conveyed by the cutlery 62 in the direction of the patient 63 Infusion liquid is based exclusively on the preselection device 21, 22 set and preprogrammed values, such as the number of drops per unit of time. If, in addition, a number of drops is preprogrammed in the input 21 of the preselection device 2 is whichever is smaller talk 40 drops per minute, the next time you start the Motor 11 the same difficulties occur again as previously described. To avoid this, input 21 sends a signal to the via line 24 Control unit 10, which has a circuit, not shown, in this control unit 10 so that the engine 11 with a further reduction the next time it is started its speed is driven.

According to FIG. 1, the buffer memory 5 is a programmable alarm transmitter 9 subordinate. This alarm device gives an alarm under certain conditions. this will in the following in context explained in more detail with FIG. 3. It it is now assumed that the drops from the cutlery 61 into the drop chamber 6 are not arrive in the desired number as set in input 21 of the preselection device 2 has been. In this case, the count grows in a positive direction and exceeds the value +5. This means that the nominal impulses of the line 42 in greater Number are present in the buffer memory 5 as are the ACTUAL pulses via the line 43.

At this limit value +5, the motor according to FIG. 3 is switched on via the line 52 and the control unit 10 and line 101 stopped. Via line 91 there the buffer counter 5 sends a signal to the alarm transmitter 9, so that the alarm transmitter 9 emits an acoustic signal or a visual alarm is triggered. This alarm can be sent to the collecting room via lines for the nursing staff, where a central monitoring device several Infusion pumps monitored. The alarm transmitter 9 also indicates which one There is an alarm, e.g. that in the present case too few drops from the cutlery 61 fall into the drip chamber # 6. If this condition persists for a long time, it could the patient is not receiving enough infusion.

This becomes a matter of course for the nursing staff when the alarm is given fixed immediately.

The alarm transmitter 9 is also from the buffer memory in another case controlled via line 92. It is now assumed that by some Circumstance, e.g. due to a defect in control unit 10, drive motor 11 is not more turns off 50 that the peristaltic pump 12 is an insufficient amount of infusion fluid the patient 63 could supply if it lasts for a long time State. If now many drops fall from the cutlery 61 into the drop chamber 6 A large number of ACTUAL impulses also reach the buffer memory 5 via the line 43. According to FIG. 3, these pulses change the count in the negative direction. At the count -9, the limit value is provided, which over the line 92 the Alarm 9 activates when there is a risk that more drops will enter the peristaltic pump drip in as was preprogrammed. The alarm transmitter 9 gives as already described also in this case its visual or acoustic alarm, which is both on the device visible or visible in a distant room as well as via electrical lines. it is audible in which room e.g. the central monitoring devices of the whole Hospital for the various life-sustaining technical devices are housed.

If, for example, the supply bottle of the infusion liquid is empty and in the worst case in the input 21 of the preselection device 2 only one drop per Minute is preprogrammed then it would take far too long to complete the limit value +5 of the buffer counter 5 (Fig. 3) is reached. In these 5 minutes the patient gets an unacceptable overdose of infusion amount and in the worst case Trap air, causing immediate embolism. To prevent this life-threatening In the status quo, the buffer counter 5 is connected to the alarm transmitter 9 via the line 93. If, for example, such a small number of drops is preprogrammed in input 21 as e.g. 1 drop per Minute, then the alarm device 9 receives over the Line 93 a signal for triggering the acoustic or optical alarm point.

In some cases the infusion fluid is very low Capillarity capacity as a result of incorrect cutlery 61, 62. Therefore it often follows a second undesired drop from the cutlery 61 into the drop chamber 6. Um To avoid this process, an overpressure is artificially created in the drop chamber 6 generated by the drop restoring device 13. This is done by im Buffer counter 5 is given a signal to control unit 10 according to its content is, which at the time via line 102 the electromagnetic coil 13 under Tension is applied and the plug 131 clamps off the hose 62.

In this way, the overpressure is generated in the drop chamber 6, so that the unwanted drip is avoided.

For the same purpose, the overpressure could also be generated thereby be that the motor 11 the eccentric shaft 121 a short time in the opposite Direction after the drop fell. In this case it would be the drop reset device 13 of course no longer required.

In Fig. 2, a modified circuit is shown, which instead the differentiators 4, 41 shown in FIG. 1 can be used. As Was said in connection with FIG. 1, the pulse edges in the differentiators 4, 41 differentiated to avoid that about the same time the TARGET pulses via line 42 and the ACTUAL pulses via line 43 in the buffer counter 5 can reach. The TARGET pulses, which are from the circuit 3 on the line 31 are present, reach the memory 44 in the exemplary embodiment in FIG. 2.

The same happens with the NOMINAL pulses, which are from the monostable Multiyibrator 8 reach the identically organized memory 45 via line 81. It does not matter at what point in time the two pulses enter the memory 44 or 45 arrive. They are stored there, and only by the clock 46 interrogated via lines 47 and 48. The clock generator 46 is e.g. Line 49 is controlled in such a way that it sends its query pulses via line 47 at a different point in time in the memory 44 of the TARGET pulses than its query pulses via line 48 in the memory 45 for the actual pulses.

This ensures that the impulses which are transmitted via line 42 itn the buffer counter 5, never coincide with the pulses, which reach the buffer counter 5 via line 43. The following circuit arrangements of Fig. 2 are the same as shown in Fig. 1 and in connection with of this figure have been described. Finally, it should be noted that that the timer 46 is not over the line by another control circuit 49 'is controllable. This clock generator 46 can be a normal run-time oscillator be.

Claims (10)

P a t e n t a n s p r ü c h e 9 Device for controlling and regulating the delivery rate of a medium within a unit of time with, a peristaltic pump, characterized by: - A clock generator Cl) for generating predetermined time pulses with a preselector t2) and with a circuit (3) for preselecting the delivery rate per unit of time and to prevent changes in the equidistance between two representing the delivery rate Impulses; - A detector (6,7) for generating measurement pulses as a function of the the pump (12) supplied amount of the medium, wherein a means (8) is provided to avoid double counting the amount of media; - a circuit (5) of the receives the impulses representing the delivery rate and the measuring impulses and in Depending on the comparison between the pulses, a signal is generated for controlling a motor (11) for driving the pump (12); - a programmable alarm device (9) to give an alarm if the flow rate of the medium is too small or too high per time unit. 2. Apparatus according to claim 1, characterized in that the clock generator (l) connected to an AC power supply network with a specific frequency and is designed as a digital reduction stage for delivering time pulses to the downstream preselection device (2), which can be controlled by an input (21), that the downstream circuit (3) represents the preselected flow rate Pulses generated per unit of time and equidistance changes between two successive ones Pulses corrected, using a transducer (4) the corrected pulses differentiated and on the downstream comparison circuit (5) there. 3. Apparatus according to claim 1, characterized in that the clock generator (1) connected to an alternating current supply network with a certain frequency and is designed as a digital reduction stage for delivering time pulses to the downstream preselection device (2), which can be controlled by an input (21), that the downstream circuit (3), which represents the preselected flow rate Pulses generated per unit of time and equidistance changes between two successive ones Corrected pulses, a memory (44) storing these pulses and with a Interrogation pulse from a clock generator (46) sends the pulse to the downstream Comparison circuit there. 4. The device according to claim 1, characterized in that the Detector designed as a housing (6) with a photoelectric scanning device (7) is through which housing (6) the medium of the pump (12) is fed, the the amount of medium proportional pulses of the photoelectric scanning device (7) get into a monostable tilting circle (8) to prevent double counting the same amount of the medium, and the output pulses of the monostable tilting circuit are differentiated in a downstream converter (41) and the differentiated Pulses are fed to the comparison circuit (5). 5. Apparatus according to claim l, characterized in that the detector is designed as a housing (6) with a photoelectric scanning device (7), by which Housing (6) the medium is fed to the pump (12), wherein the photoelectric scanning device pulses proportional to the amount of medium (7) get into a monostable tilting circuit (8) to prevent double counting the same amount of the medium, and the output pulses of the monostable tilting circuit are stored in a downstream memory (45), which memory by an interrogation pulse from a timing generator t46) the stored pulse the downstream comparison circuit (5). 6. The device according to claim 1r, characterized in that the comparison circuit (5) is designed as a buffer counter with zero crossing logic, with the pulses received on one input from the pulses received on the other input are subtracted, so that depending on the comparison result, a subordinate Control unit (10) controls the speed of the drive motor (11) of the pump (12). 7. The device according to claim 6, characterized in that the programmable Alarm transmitter (9) the comparison circuit (5) n, is achored and if the value falls below or exceeding at least one limit value to be promoted per unit of time Quantity of the medium triggers an alarm. 8. Device according to claims 2 and 6, characterized in that that the input (21) for the preselection device (2) has a second output (24) for the Control unit (10) of the drive motor (all) of the pump (12), so that the control unit can be influenced by the comparison circuit (5) and the input (21). 9. The device according to claim 1, characterized by: a drop reset device (13) for generating an overpressure in the housing (6), which device (13) from Control device (10) of the drive motor (11) of the pump (13) can be controlled. 10. The device according to claim 1, characterized in that the Motor (11) of the pump (12) is designed as a stepping motor. Blank page rse i