Sterile area wire anti-pulling alarm circuit

Abstract

The utility model relates to medical equipment safety technical field especially, and more particularly to a sterile area wire anti -pulling alarm circuit, including tension detection module, signal processing module, audible -visual alarm circuit, capacitor coupling suppression circuit, dynamic threshold setting module, the tension detection module includes difference amplifier circuit, not less than one strain gauge sensor, the signal processing module contains RC filter circuit, voltage comparator, the input of RC filter circuit is connected with the output of difference amplifier circuit, and its output is connected with the signal input of voltage comparator, capacitor coupling suppression circuit is connected between the output of difference amplifier circuit and ground, the utility model can generate floating alarm threshold through dynamic threshold setting module automatic adaptation wire initial state, and the high -frequency interference is filtered out in combination with capacitor coupling suppression circuit, solves the wire anti -pulling false alarm problem caused by installation difference and electromagnetic interference in the sterile medical environment.

Description

Technical Field

[0001] This utility model relates to the field of medical equipment safety technology, and in particular to an alarm circuit for preventing the wires in sterile areas from being pulled. Background Technology

[0002] In sterile medical areas, such as operating rooms and ICUs, various vital sign monitoring and treatment devices need to be connected to patients via wires. During clinical use, these wires are often accidentally pulled due to the movement of medical staff, changes in patient position, or relocation of equipment, which may lead to disconnection or even damage to the equipment and directly endanger patient safety.

[0003] Currently, most existing wire pull alarm technologies rely on mechanical structures or simple circuit continuity detection. However, mechanical structures are difficult to clean and disinfect in sterile environments and are prone to leaving contaminants. In circuit detection solutions, most existing technologies use single-point strain gauge detection or simple voltage comparison circuits. Although these solutions avoid mechanical structures, their alarm thresholds are usually fixed and preset, which cannot adapt to the initial tension differences when different wires are installed or the sensor baseline drift caused by changes in ambient temperature during use, leading to false alarms in practical applications.

[0004] In addition, the strong electromagnetic interference generated by high-frequency medical equipment (such as electrosurgical units and ultrasound equipment) in the medical environment can easily be introduced into the detection circuit, resulting in insufficient anti-interference capability of traditional circuits and further increasing the probability of false alarms.

[0005] Therefore, it is necessary to further improve the anti-pull alarm circuit for wires in sterile areas. Utility Model Content

[0006] The technical problem to be solved by this utility model is to overcome the existing defects and provide a wire pull-proof alarm circuit for sterile areas. The circuit automatically adapts to the initial state of the wire and generates a floating alarm threshold through a dynamic threshold setting module. Combined with a capacitive coupling suppression circuit to filter out high-frequency interference, it effectively solves the problem of false alarms caused by wire pull-proofing due to installation differences and electromagnetic interference in sterile medical environments.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a wire anti-pull alarm circuit for sterile areas, comprising a tension detection module, a signal processing module, an audible and visual alarm circuit, a capacitive coupling suppression circuit, and a dynamic threshold setting module;

[0008] The tension detection module includes a differential amplifier circuit and at least one strain gauge sensor; the signal processing module includes an RC filter circuit and a voltage comparator; the input terminal of the RC filter circuit is connected to the output terminal of the differential amplifier circuit, and its output terminal is connected to the signal input terminal of the voltage comparator.

[0009] The capacitive coupling suppression circuit is connected in parallel between the output of the differential amplifier circuit and ground;

[0010] The dynamic threshold setting module includes a baseline sample-and-hold circuit and an analog adder circuit. The input of the baseline sample-and-hold circuit is connected to the output of the differential amplifier circuit to obtain the baseline value of the tension signal in the initial state of the system. Its output is connected to the input of the analog adder circuit. The output of the analog adder circuit is electrically connected to the reference voltage terminal of the voltage comparator to provide a dynamic alarm threshold that drifts with the baseline.

[0011] The output of the voltage comparator is electrically connected to the control input of the audible and visual alarm circuit.

[0012] Preferably, the baseline sample-and-hold circuit includes an analog switch, a sampling capacitor, and a voltage follower; the input terminal of the analog switch is connected to the output terminal of the differential amplifier circuit to receive the tension signal output by it, and its output terminal is connected to one end of the sampling capacitor, while the other end of the sampling capacitor is grounded; the non-inverting input terminal of the voltage follower is connected to the common node of the sampling capacitor and the analog switch, and its output terminal outputs the baseline voltage;

[0013] The analog adder circuit includes a non-inverting operational amplifier, a first input resistor, a second input resistor, and an adjustable resistor. The non-inverting input of the non-inverting operational amplifier is connected to the output of a voltage follower through the first input resistor, and the non-inverting input of the non-inverting operational amplifier is also connected to the adjustable resistor through the second input resistor to provide an offset voltage. The output of the non-inverting operational amplifier is electrically connected to the reference voltage terminal of a voltage comparator to output a dynamic alarm threshold voltage.

[0014] Preferably, the dynamic threshold setting module further includes a delay start circuit for controlling the timing of baseline sampling; the delay start circuit includes an RC delay network and a Schmitt trigger connected in sequence, the output of the Schmitt trigger being connected to the control terminal of the analog switch, for closing the analog switch for a preset duration after the system is powered on and reaches stability, so as to complete the baseline sampling.

[0015] Preferably, the delayed start circuit further includes an NPN transistor inverter, a base resistor, and a pull-up resistor;

[0016] The RC delay network consists of a delay resistor and a delay capacitor connected in series between the power supply and ground. The connection point of the delay resistor and the delay capacitor is connected to the base of the NPN transistor inverter through a base resistor. The collector of the NPN transistor inverter is connected to the power supply through a pull-up resistor, and its collector is also connected to the input terminal of the Schmitt trigger.

[0017] Preferably, the delayed start circuit further includes a status indicator circuit consisting of a light-emitting diode and a current-limiting resistor connected in series, and the status indicator circuit is connected in parallel between the collector of the NPN transistor inverter and the power supply.

[0018] Preferably, the baseline sample-and-hold circuit further includes a high-resistance bleed resistor connected in parallel across the sampling capacitor.

[0019] Preferably, the tension detection module further includes a bidirectional limiting circuit; the output of the strain gauge sensor is connected to the input of the differential amplifier circuit through the bidirectional limiting circuit.

[0020] Compared with the prior art, the beneficial effects of this utility model are:

[0021] This invention, through a dynamic threshold setting module including a baseline sampling and holding circuit and an analog adder, can automatically learn and lock the tension baseline of the initial state of the system, and generate a dynamic alarm threshold that floats with the baseline; this overcomes the problem of false alarms caused by inconsistent initial installation tightness of wires or ambient temperature drift, and significantly improves alarm accuracy.

[0022] The circuit employs designs such as capacitive coupling suppression circuits to specifically filter out high-frequency interference generated by medical devices (such as electrosurgical units). Meanwhile, the tension detection module uses a parallel strain gauge network and a bidirectional limiting circuit to jointly improve the reliability of signal detection and the shock resistance of the front-end circuit, ensuring that the system operates stably in the complex electromagnetic environment of the sterile area. Attached Figure Description

[0023] Figure 1 This is a block diagram of the overall structure of this utility model;

[0024] Figure 2 This is a schematic diagram of the dynamic threshold setting module circuit of this utility model;

[0025] Figure 3 This is a schematic diagram of the capacitive coupling suppression circuit of this utility model;

[0026] Figure 4 This is a partial circuit diagram of the tension detection module of this utility model. Detailed Implementation

[0027] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0028] Please see Figure 1-4 This utility model provides a technical solution: a wire anti-pull alarm circuit for sterile areas, including a tension detection module, a signal processing module, an audible and visual alarm circuit, a capacitive coupling suppression circuit, and a dynamic threshold setting module;

[0029] The tension detection module includes a differential amplifier circuit and a strain gauge sensor. In this embodiment, three foil strain gauges are preferably arranged in parallel at critical parts of the conductor that are prone to tension. This parallel structure ensures that if any strain gauge deforms due to tension, causing a change in resistance, the overall output signal will change, thus improving the reliability of the system. The signal processing module includes an RC filter circuit and a voltage comparator. The input terminal of the RC filter circuit is connected to the output terminal of the differential amplifier circuit, and its output terminal is connected to the signal input terminal of the voltage comparator.

[0030] The capacitive coupling suppression circuit is connected in parallel between the output terminal of the differential amplifier circuit and ground. Specifically, the differential amplifier circuit can be implemented using an instrumentation amplifier such as AD620. The capacitive coupling suppression circuit consists of an inductor L1, a capacitor C6, and a damping resistor R10. The inductor L1 and the capacitor C6 are connected in series, and the damping resistor R10 is connected in parallel across the inductor L1.

[0031] The dynamic threshold setting module includes a baseline sample-and-hold circuit and an analog adder circuit. The input of the baseline sample-and-hold circuit is connected to the output of the differential amplifier circuit to obtain the baseline value of the tension signal in the initial state of the system. Its output is connected to the input of the analog adder circuit. The output of the analog adder circuit is electrically connected to the reference voltage terminal of the voltage comparator to provide a dynamic alarm threshold that drifts with the baseline.

[0032] The output of the voltage comparator is electrically connected to the control input of the audible and visual alarm circuit.

[0033] Furthermore, the baseline sample-and-hold circuit includes an analog switch U1, a sampling capacitor C_hold, and a voltage follower U2. The analog switch U1 can be, for example, an SN74LVC, whose input is connected to the output of a differential amplifier circuit to receive its output tension signal V_signal. Its output is connected to one end of the sampling capacitor C_hold, and the other end of the sampling capacitor C_hold is grounded to store the sampled baseline voltage. The voltage follower U2 can be a high input impedance operational amplifier, whose non-inverting input is connected to the common node of the sampling capacitor C_hold and the analog switch U1, and whose output outputs the baseline voltage V_baseline.

[0034] The analog adder circuit includes a non-inverting operational amplifier U3, a first input resistor R1, a second input resistor R2, and an adjustable resistor R5. The non-inverting operational amplifier U3 can be, for example, an LM358. Its non-inverting input is connected to the output of a voltage follower U2 through the first input resistor R1, and the non-inverting input is also connected to the adjustable resistor R5 through the second input resistor R2 to provide an offset voltage V_offset. The output of the non-inverting operational amplifier U3 is electrically connected to the reference voltage terminal of a voltage comparator to output a dynamic alarm threshold voltage V_threshold.

[0035] The non-inverting adder operational amplifier U3 is configured as a non-inverting adder circuit; its inverting input terminal is grounded through resistor Rg and connected to the output terminal through feedback resistor Rf; its output dynamic alarm threshold voltage V_threshold=V_baseline+V_offset; V_offset is set by adjusting the adjustable resistor R5, representing the voltage margin corresponding to the allowable safe pulling force.

[0036] Furthermore, the dynamic threshold setting module also includes a delay start circuit for controlling the timing of baseline sampling; the delay start circuit includes an RC delay network and a Schmitt trigger U4 connected in sequence. The Schmitt trigger can be, for example, an NC7SZ04M5X. Its output is connected to the control terminal of the analog switch U1, and is used to close the analog switch U1 for a predetermined time after the system is powered on and reaches stability to complete the baseline sampling.

[0037] Furthermore, the delayed start circuit also includes an NPN transistor inverter Q1, a base resistor R6, and a pull-up resistor R7;

[0038] The RC delay network consists of a delay resistor R3 and a delay capacitor C4 connected in series between the power supply and ground. The connection point of the delay resistor R3 and the delay capacitor C4 is connected to the base of the NPN transistor inverter Q1 through the base resistor R6. The voltage at this connection point will rise slowly after power-on. The collector of the NPN transistor inverter Q1 is connected to the power supply through the pull-up resistor R7, and its collector is also connected to the input terminal of the Schmitt trigger U4.

[0039] Furthermore, the delayed start circuit also includes a status indicator circuit consisting of a light-emitting diode LED1 and a current-limiting resistor R8 connected in series. The status indicator circuit is connected in parallel between the collector of the NPN transistor inverter and the power supply to visually display the system status.

[0040] Furthermore, the baseline sample-and-hold circuit also includes a high-resistance bleeder resistor R4, which is connected in parallel across the sampling capacitor C_hold. Its resistance value can be selected as 10MΩ. After the system has been running for a long time or after power failure, it provides a slow discharge path for the sampling capacitor C_hold to prevent charge accumulation from causing baseline voltage drift and to ensure the accuracy of the next sampling.

[0041] Furthermore, the tension detection module also includes a bidirectional limiting circuit. The output of the strain gauge sensor is connected to the input of the differential amplifier circuit through the bidirectional limiting circuit. Specifically, the bidirectional limiting circuit includes Zener diodes D1, D2, D3, and D4, and small current-limiting resistors R11 and R12. Taking the non-inverting input of the differential amplifier circuit as an example, the anode of Zener diode D1 is connected to the non-inverting input, and its cathode is connected to the power supply. The anode of Zener diode D2 is connected to the non-inverting input, and its cathode is grounded. The output of the strain gauge sensor is connected to the non-inverting input in series with the small current-limiting resistor R11. The structure of the inverting input is the same as that of the non-inverting input. When a high-voltage pulse is introduced due to static electricity or accidental exposure, the Zener diodes will quickly conduct and clamp it to a safe voltage, thereby protecting the differential amplifier circuit.

[0042] To achieve the above-mentioned circuit functions and meet the special requirements of the sterile area, the present invention has made the following design for the physical carrier and energy supply of the circuit: the circuit of the present invention is integrated on a flexible printed circuit board, so that the entire alarm circuit can be closely attached to or embedded in the sheath of the medical lead wire; the power supply of the circuit of the present invention can be a rechargeable miniature button lithium battery, which is small in size and can be directly installed on the flexible circuit board.

[0043] The working principle of this utility model is as follows: by using strain gauge sensors arranged in parallel at key parts of the conductor, the physical tension on the conductor is converted into a resistance change signal; a differential amplifier circuit is used to amplify the weak resistance change signal into a voltage signal that can be processed; and a capacitive coupling suppression circuit connected in parallel between the amplifier output terminal and ground is used to suppress electromagnetic interference from high-frequency equipment in the medical environment.

[0044] After the system is powered on, a delayed start circuit ensures circuit stability. Then, the analog switch is closed, and the voltage signal under the current state is stored as a baseline value in the sampling capacitor. The voltage follower reads this baseline value and then adds a settable safety margin voltage through an adder circuit to generate a dynamic alarm threshold that adapts to the installation state. The real-time tension signal purified by the RC filter circuit is compared with the dynamic alarm threshold in the voltage comparator. When the real-time signal exceeds the dynamic threshold, it is determined to be a dangerous pulling state, and the voltage comparator output signal drives the audible and visual alarm circuit to issue a warning.

[0045] The working principle of this utility model is as follows: the alarm circuit integrated on the flexible circuit board is arranged in the sterile area along with the medical lead wire; after the power is turned on, the system enters the initialization stage, at which time the status indicator light is lit, and the circuit learns and locks the current installation stress state of the lead wire as a reference.

[0046] During normal operation, after initialization is complete, the status indicator light turns off and the system enters monitoring mode; the circuit can automatically adapt to baseline drift caused by temperature changes or slight displacement of wires, thus avoiding false alarms.

[0047] When the alarm is triggered, if the wire is accidentally pulled and the pulling force exceeds the safety margin set according to the initial state, the system will immediately trigger an audible and visual alarm. Different safety margins can be set by adjusting the adjustable resistor to adapt to the sensitivity requirements of different application scenarios.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A wire pull-resistant alarm circuit for sterile areas, comprising a tension detection module, a signal processing module, an audible and visual alarm circuit, a capacitive coupling suppression circuit, and a dynamic threshold setting module, characterized in that: The tension detection module includes a differential amplifier circuit and at least one strain gauge sensor; the signal processing module includes an RC filter circuit and a voltage comparator; the input terminal of the RC filter circuit is connected to the output terminal of the differential amplifier circuit, and its output terminal is connected to the signal input terminal of the voltage comparator. The capacitive coupling suppression circuit is connected in parallel between the output of the differential amplifier circuit and ground; The dynamic threshold setting module includes a baseline sample-and-hold circuit and an analog adder circuit. The input of the baseline sample-and-hold circuit is connected to the output of the differential amplifier circuit to obtain the baseline value of the tension signal in the initial state of the system. Its output is connected to the input of the analog adder circuit. The output of the analog adder circuit is electrically connected to the reference voltage terminal of the voltage comparator to provide a dynamic alarm threshold that drifts with the baseline. The output of the voltage comparator is electrically connected to the control input of the audible and visual alarm circuit.

2. The alarm circuit for preventing wire pulling in a sterile area according to claim 1, characterized in that: The baseline sample-and-hold circuit includes an analog switch, a sampling capacitor, and a voltage follower. The input of the analog switch is connected to the output of the differential amplifier circuit to receive the tension signal it outputs. Its output is connected to one end of the sampling capacitor, and the other end of the sampling capacitor is grounded. The non-inverting input of the voltage follower is connected to the common node of the sampling capacitor and the analog switch, and its output outputs the baseline voltage. The analog adder circuit includes a non-inverting operational amplifier, a first input resistor, a second input resistor, and an adjustable resistor. The non-inverting input of the non-inverting operational amplifier is connected to the output of a voltage follower through the first input resistor, and the non-inverting input of the non-inverting operational amplifier is also connected to the adjustable resistor through the second input resistor to provide an offset voltage. The output of the non-inverting operational amplifier is electrically connected to the reference voltage terminal of a voltage comparator to output a dynamic alarm threshold voltage.

3. The alarm circuit for preventing wire pulling in a sterile area according to claim 2, characterized in that: The dynamic threshold setting module also includes a delay start circuit for controlling the timing of baseline sampling. The delay start circuit includes an RC delay network and a Schmitt trigger connected in sequence. The output of the Schmitt trigger is connected to the control terminal of the analog switch. After the system is powered on and reaches stability, the analog switch is closed for a preset duration to complete the baseline sampling.

4. The alarm circuit for preventing pull on conductors in a sterile area according to claim 3, characterized in that: The delayed start circuit also includes an NPN transistor inverter, a base resistor, and a pull-up resistor; The RC delay network consists of a delay resistor and a delay capacitor connected in series between the power supply and ground. The connection point of the delay resistor and the delay capacitor is connected to the base of the NPN transistor inverter through a base resistor. The collector of the NPN transistor inverter is connected to the power supply through a pull-up resistor, and its collector is also connected to the input terminal of the Schmitt trigger.

5. The aseptic area wire anti-pull alarm circuit according to claim 4, characterized in that: The delayed start circuit also includes a status indicator circuit consisting of a light-emitting diode and a current-limiting resistor connected in series. The status indicator circuit is connected in parallel between the collector of the NPN transistor inverter and the power supply.

6. The alarm circuit for preventing pull on conductors in a sterile area according to claim 2, characterized in that: The baseline sample-and-hold circuit also includes a high-resistance bleed resistor connected in parallel across the sampling capacitor.

7. The alarm circuit for preventing pull on conductors in a sterile area according to claim 1, characterized in that: The tension detection module also includes a bidirectional limiting circuit; the output of the strain gauge sensor is connected to the input of the differential amplifier circuit through the bidirectional limiting circuit.

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