DE2733694A1 - Infusion metering appliance - with count pulses for drip sensor and decoder for adjustment of closure element opening - Google Patents

Abstract

An infusion metering appliance has a closure element (rotary magnet) with the amt. of opening stroke controlled by a digital/analog converter which is fed by an UP/DOWN counter. A timing pulse generator produces two pulse trains, the second with a higher frequency. The first trains opens the closure element and releases another counter for the pulses of the second train; it is stopped by an output signal from a drip sensor which also shuts off the closure element. A decoder after this counter actuates the UP/DOWN counter in case of discrepancies of the counter from a setting and increases or reduces the opening stroke of the closure element. This results in a very exact metering of the infusion rate and its maintenance. It operates with a high functional reliability so that faults cannot endanger a patient. All defects are monitored by alarm signals or shut-down.

Description

Designation: infusion dosing device

The invention relates to an infusion dosing device for control one inserted into the hose line between the infusion bottle and the infusion set Closure member as a function of output signals of a closure member connected upstream Drop sensor in a drop chamber.

During infusion therapy, a storage bottle that has over a patient is suspended, infusion fluid through a hose line and a cannula is fed to the patient. The infusion area continues to show Ventilation valve, via which pressure equalization to the outside air takes place. the Drop speed or the number of drops can be determined by squeezing control the hose line.

However, this control is very imprecise and requires continuous Monitoring by medical personnel, which is extremely undesirable.

with There are still devices known whose help the number of Drop is controllable. However, these devices do not allow very precise control the drop speed and the drop size, so that the amount of infusion liquid supplied is very difficult to determine and control. The danger continues of failures in such devices are very large and such failures can be extreme have undesirable effects.

The invention is based on the object of an infusion dosing device of the type mentioned to create a very precise dosage and compliance allows a desired amount of infusion liquid and continues to do so works reliably so that there is no risk of unnoticed errors or failures consists.

This object is achieved by the invention specified in claim 1 solved.

This design of the infusion metering device achieves that the drop formation always takes place in the same time, so that the drop size is always the same and a direct assignment of the number of drops to the amount of liquid is possible. Furthermore, there is an automatic adjustment to changed external conditions, so that, for example, when the pressure rises or falls, no or only one very brief changes in the drop size can occur.

According to an advantageous embodiment of the invention, the forward-backward counter is can be preset to a predetermined value by switching on the device. This predetermined value is a mean empirically determined value, which is approximately the Properties of the infusion set and the inflation fluid are taken into account.

Since the first pulse sequence determines the number of drops per unit of time, it is advantageous with the help of frequency dividers controlled by coding switches adjustable, so that even very small numbers of drops per unit of time can be achieved, without the accuracy of the amount of liquid per drop resulting in the total amount per unit of time is impaired.

According to a further embodiment of the invention, it is possible to use the upstream of adjustable frequency dividers with a scaling stage, which is a programmable Includes frequency divider and a coding matrix so that a calibration of the number of drops per minute determining code switch in values of the amount of liquid is possible.

According to a further advantageous embodiment of the invention is it is done that, in the event of deviations in the count of the counter, the specified Exceed value, a forwarding of one or more of the highest valued # s Setting of the up / down counter takes place. In this way there can be strong deviations corrected very quickly will be followed by the exact Fine control becomes effective.

It is also advantageous if a large deviation from the predetermined count of the counter to the top Up-count input of the up-down counter is a pulse train of higher frequency is fed until an output signal occurs. In this catfish becomes a very rapid adaptation to changed conditions is achieved, for example, as a result caused a patient to bend his arm, causing an increase in pressure and causing a decrease in the flow rate through the cannula.

According to a further embodiment of the invention St provided that in the event of a large deviation from the predetermined count of the counter downwards a rapid downward switching of the up-down counter emerges will. This reliably prevents overdosing.

To protect against malfunctions, according to one embodiment of the invention a first monitoring device is provided which, when the permissible Range of the up / down counter triggers an alarm. Furthermore, a second monitoring circuit can be provided, which in the event of a defect in the infusion dosing device after a predetermined number of pulses of the first Pulse train triggers an alarm.

Another monitoring circuit is preferably used for the drop sensor that triggers an alarm if an error occurs.

It is advantageous if an error occurs in the Closing member controlling circle caused a permanent closing of the Versohlußgiledes will.

A further increase in the accuracy of the drop formation can thereby can be achieved that the opening of the shutter member controlling current an alternating voltage is superimposed, so that a wobble of the closure member is caused.

The wobble stroke is preferably proportional to the control current of the magnet controlling the closure member.

As in the case of errors or interruptions in the determining the first pulse train Coding switches large deviations can occur, these coding switches are used preferably with the help of each to the direct and complementary outputs of the Coding switch connected logic elements monitored for interruptions to be determined in the coding switch.

In particular, the highest rated levels of the coding switch monitored by two logic elements, since these coding switches if an error occurred, the most serious consequences would be expected.

The invention is illustrated below with reference to one in the drawing Embodiment explained in more detail.

The drawing shows: FIG. 1 a greatly simplified block diagram of the infusion dosing device; 2a-20 and 2e, 2f together show a detailed circuit diagram of the infusion dosing device; FIG. 2d shows the type of combination of FIGS. 2a, 2b and 2e, 2f to form the circuit diagrams of the clock generator or the remaining part the circuit.

The block diagram shown in Fig. 1 is greatly simplified, the basic mode of operation of the infusion dosing device more easily recognizable close. This block diagram includes a time base 1, the two pulse trains fi and f2, of which f2 has a higher frequency. The closing link, which is in the form of a rotary magnet M, for example, is via a Control logic 2 controls, on the one hand, the opening and closing of the locking member M and, on the other hand, the degree of opening of the shutter based on the output signal of the digital-to-analog converter 3 is determined. The output signal fi of the time base 1 becomes a counter 4 and the input controlling the opening of the closure member Control logic 2 supplied. A pulse of the pulse train fl with a certain level on the one hand releases the counter 4 so that it counts the pulses of the pulse train f 2 can and on the other hand, the closure member r. in one through the Digital-to-analog converter 3 opened to a certain extent. The supply of pulses to the The pulse sequence f2 is sent to the counter 4 and the link is left behind Occurrence of an output action pulse from the drop sensor 5 indicating a drop Via a bistable multivibrator circuit 6 and a gate connected upstream of the counter 4 7 stopped and the output of this counter 4 is in a decoding circuit checks whether it is above or below a specified value. When occurring the decoding circuit gives a deviation from this predetermined count 8 a forward or reverse switching pulse an up-down counter 9, the outputs of which are connected to the inputs of the digital-to-analog converter 3.

The operation of the infusion dosing device according to the simplified The block diagram is as follows: The forward-backward counter 9 is an example preset to a certain value to which a certain opening position of the Closure member M corresponds. When the shutter member M is opened by the time base 1 a drop is formed within a certain time, the falling of which is caused by the drop sensor 5 is detected. If the drop is not within a predetermined Time is formed that a predetermined number of the counted by the counter 4 Pulses, there is a larger or smaller counter reading in this counter 4, then via the decoding circuit 8 to advance the up / down counter 9 is used, whereby the digital-to-analog converter 3 exercises the opening stroke of the shutter member M is increased or decreased accordingly.

In this way there is always a constant drop formation speed, so that the volume of each individual drop is the same in a reproducible manner and an assignment of the number of drops to the amount of liquid becomes possible.

Figures 2a, 2b and 2e, 2f, the combination of which in Fig.

2d together form a detailed circuit diagram of the infusion metering device, wherein in Fig. 2a to c the time base forming the clock generator and the decade switch monitoring is shown, while in Fig. 2e, f the remaining parts of that shown in Fig. 1 Block diagrams are shown.

a-c The clock generator uFrißt2e) shown in Fig. 2 # as an oscillator switched integrated circuit IC2r, the output frequency of which is 4551.11 Hz. The output signal of this oscillator is connected to the input via a logic element IC50 a programmable binary counter IC40, its programming inputs with a coding matrix are connected, which an adaptation of the number of drops to them this allows the amount of liquid in milliliters, so that the still to The coding switch is calibrated directly in units of the amount of liquid can be. The output of the integrated circuit IC40 becomes the clock inputs of 3 programmable frequency dividers supplied, whose data inputs with the already mentioned coding switches are connected. These three frequency dividers ICSO to IC100 control the desired infusion rate in ml / h and the output signal of the three frequency dividers are ver üpft in a link IC110 and two subsequent ones 1: 16- (Fig.2e) frequency dividers IC60 and IC70% supplied, their output signal with With the help of a Jx flip-flop circuit IC160 and a further logic element IC130 is processed as a single pulse, the output signal of the logic element IC130 supplies the first pulse sequence representing the time base. The oscillator frequency of 4551.11 Hz is further divided by 10 via an integrated circuit IC30 and for the acoustic alarm via a link ICI 10 and a transistor T20 used on a speaker. The frequency of 455 Hz obtained in this way will continue in the integrated circuit IC140 divided by 16 and results in the control frequency for the drop formation of 28.4 Hz. Another integrated circuit IC120 (Fig.2e) halves this frequency from 28.4 Hz to 14.2 Hz or 7.1 Hz.

The 14.2 Hz are needed for sweeping the power amplifier while 7.1 Hz for slow regulation with a liquid volume of less than 80 ml / h be used.

The frequency of 14.2 Hz is still a frequency divider divided by 12 IC150 supplied, which provides an output signal with a frequency of 1.18 Hz. In the event of an alarm, there are logical connections at connections 2 and 3 of the IC110 linkage elements ONE level. The output signals with the frequencies 455 Hz or 1.18 Hz can be over T20 and T30 trigger the acoustic and visual alarm at a rhythm of 1.18 Hz.

The integrated circuit IC100 is a monostable flip-flop circuit switched and in the event of an alarm gives a contact via relay REL1 for one second to the nurse call.

The output signals of the clock generator in Flug.tcd2arrgesteXten are Inputs of the rest of the circuit via the terminals which are also identified identically in Fig. 2a-c fed. The time base signal which forms the first pulse train and which is applied to terminal 2 according to Figures 2c and 2e is applied, is via a transistor Tii (F1g.2f) to open the closure member in the form of the 'rotary magnet M leads supplied.

The time base signal continues to enable counter IC1), which enables the counter 4 according to fig. The supply of the pulses forming the pulse train F2 at connection 3 according to Fig. 2c and 2e is controlled with the help of the sensor electronics, which includes a lamp L and a light-emitting diode D. The output signal of the light emitting diode is processed by operational amplifiers IC2a and IC2b and a transistor T2, whereby a control loop is formed, the aging of the sensor lamp, a temperature drift the components as well as the infusion set that is fogged up with moisture. A Another operational amplifier IC2b amplifies the output signal, which is then the integrated Circuit IC19a is fed through the integrated circuits IC16a and b the drop signal with the second pulse train with pulses of 28.4 Hz and 7.1 respectively Hz synchronized.

This second pulse train is connected to terminal 4 of a logic element IC17 supplied, which forwards the second pulse train to the clock input of the counter 1C13. When a drop signal occurs, these pulses are passed on via the integrated circuit IC16a and the connection of the logic element IC; 6 interrupted. From the release of the counter 1C13 by the time base signal and the order of the Rotary magnet M until the appearance of the drop signal is a certain number of Pulses of the second pulse train are counted by the counter 13.

This pulse train has a frequency of 28.4 Hz when dosing of more than 80 ml should be used, while at a dosage of below 80 ml a frequency of 7.1 Hz is used. The drop signal occurs before the counter reading 12 is reached, the difference to the counter reading 12 becomes for switching backwards the up / down counter 9 of FIG. 1 forming integrated circuits 103 and 104 are used.

If the difference to the counter reading 12 corresponds to more than 5 pulses, a quick reverse shift occurs via impulses saf, which are provided by the integrated Circuit 1012 are forwarded, the number of these pulses via the integrated Circuit IC15 is controlled. If the drop signal occurs only after the counter reading has been reached 15 on, the up / down counter IC3, 1C4 is initially increased by one step switched upwards. At the same time this signal becomes an integrated Circuit IC14 is supplied, which initiates a fast forward regulation with 28.4 Hz, when the counter IC13 reaches count 15 again.

The output signals of the up / down counter IC3, 104 (Fig.2f) are fed to a digital-to-analog converter 1C1, the output of which is via another Operational amplifier IC2d controls the opening stroke of the rotary magnet M. The control current for the rotary magnet M a wobble signal is superimposed on the diode D3, whose Amplitude depends on the control current generated by the digital-to-analog converter is. This dependency is achieved via the diode D1 and the transistor T4. Of the digital control range of this system comprises 256 steps, so that 256 different Positions of the rotary magnet are possible. When the range of the up / down counter is exceeded upwards or downwards is via the connections 9 and 10 of the logic circuit ICll output an alarm signal to a flip-flop circuit IC19b, which generates an alarm triggers. Furthermore, the entire system of the reverse control is integrated Circuit IC6 and IC7 monitored. With an aperiodic drop wheel; the example can be caused by splashing water in the drop sensor, is over the integrated circuit IC18a and b prevents backward regulation.

(Fi .2f) The transistors T8 to Til and T13 monitor the circuit of the rotary magnet M. These transistors are connected in such a way that that if any component faults occur, the rotary magnet M is always de-energized so that no dangerous operating states can occur.

A decade switch monitoring function is also used to further increase operational safety provided, which can be seen from Fig. 2b. As can be seen from Fig. 2a, has this decade switch monitoring logic elements, each of which the direct and the complementary output signals used as coding switches Decade switch are supplied. Since the outputs of the decade switches have resistors are connected to the positive operating voltage, result in the occurrence of a Interruption in the decade switches logical ZERO level on the relevant logic element, so that an alarm signal is supplied via the terminal 8 of the circuit of FIG. 2b will. The most significant bits of the decade switches are each made by two logic elements monitored in order to achieve additional security against errors, in particular would have a very strong impact at these stages.

The infusion dosing device described enables a very precise one and reliable and, in particular, reliable dosing of infusions, whereby all occurring errors are recognized immediately and lead to the output of an alarm. If there are small changes in the drop formation time, an Advance of the up / down counter only by one or a few steps, while if larger deviations occur, a rough correction is initially made, whereupon the fine control again becomes effective. In this way it is possible external influences very quickly to be taken into account and compensated so that the desired Infusion amount is adhered to very precisely.

Claims (14)

Claims: 1. Infusion dosing device for controlling an in the Hose line between the infusion bottle and infusion set inserted closure member as a function of the output signals of a drop connected upstream of the closure member. sensors in a droplet chamber, thus g e k e n n n -mark e t that the size of the opening stroke of the closure member (M) by the output signal a digital / analog converter (ICl) is determined, whose inputs with the outputs an up # down counter (IC3, IC4) are connected to that a clock generator is provided, the first and second pulse trains delivers, the frequency of the second pulse train is greater than that of the first pulse train that the first pulse train causes the closure member (M) to open and a counter (ICl3) to be released, which counts the impulses of the second impulse sequence and closes when one occurs of the closure member (rA) causing output signal from the drop sensor (L, D) is stopped, and that the counter (IC13) is a decoding circuit (IC8, In10, (IC17) is connected downstream, which in the event of a deviation of the counter reading from a certain Counter reading up or down the up / down counter (IC3, IC4) advances forward or backward and thus the opening stroke of the locking member (#) increases or decreases. 2. Infusion dosing device according to claim 1, characterized in that g e k e n n -z e 1 c h n e t that the forward-backward counter (IC3, IC4) by switching on the Device can be preset to a predetermined value. 3. Iflsionsdosiergerät according to claim 1 or 2, characterized g e k e n n z e i c h n e t that the frequency of the first Pulse train the Number of drops per unit of time determined and with the help of by coding switch controlled frequency dividers (IC80, IC90, IC100) is adjustable. 4. Infusion dosing device according to claim 3, characterized in that g e k e n n -z e i c h n e t that the adjustable frequency dividers are preceded by a scale stage which includes a programmable frequency divider (IC40) and a coding matrix and a calibration of the code switches determining the number of drops per minute in values the amount of liquid allows. 5. Infusion dosing device according to one of the preceding claims, characterized g e k e n n n n z e i c h n e t that in the event of deviations in the counter reading of the counter (IC13) that exceed a specified value, an advance of an or several of the highest valued digits of the up / down counter (IC3, IC4) takes place. 6. Infusion dosing device according to one of the preceding claims, characterized it is not noted that if a large deviation occurs repeatedly from the predetermined count of the counter (IC13) up to the up-counting input the up / down counter (1C3, IC4) is supplied with a pulse train of higher frequency until there is an output signal from the drop sensor. 7. Infusion dosing device according to one of the preceding claims, characterized it is noted that in the event of a large deviation from the predetermined Counter reading of the counter (IC13) a fast downward switching of the Up-down counter is caused. 8. Infusion dosing device according to one of the preceding claims, characterized it is not indicated that a first monitoring device (IC11, IC19) is provided when the permissible range of the up / down counter is exceeded (IC3, IC4) triggers an alarm. 9. infusion dosing device according to any one of the preceding claims, characterized it is noted that a second monitoring circuit (IC6, IC7) is provided is that when a defect occurs in the infusion dosing device after a predetermined Number of pulses of the first pulse train triggers an alarm. 10. Infusion dosing device according to one of the preceding claims, in that a further monitoring circuit (IC2) for the drop sensor is provided, which generates an alarm if an error occurs triggers. 11. Infusion dosing device according to one of the preceding claims, as a result, if an error occurs in the Closure member (M) controlling circuit a permanent closing of the closure member is caused. 12. Infusionsdos iergerät according to one of the preceding claims, by noting that the controlling the front of the closure member Current an alternating voltage is superimposed, so that a wobble of the closure member is caused. 13s infusion dosing device according to claim 12, characterized in that it is not 1 c h n e t that the wobble stroke is proportional to the control current of the magnet. 14. Infusion dosing device according to one of the preceding claims, by the fact that a monitoring circuit for the Frequency of the first pulse train (fi) determining coding switch is provided, that this monitoring circuit through with the direct and complementary outputs the coding switch is formed with connected logic elements, the outputs of which are interconnected are and emit a logical NUIL level if at both inputs of the logic elements at the same time a logical ONE occurs.