CN210605006U - Capacitance induction type liquid detection device of calculation frequency mode - Google Patents

Abstract

The utility model relates to a capacitance induction type liquid detection device with a frequency calculation mode, which belongs to the technical field of infusion control equipment of medical instruments, and comprises an electrode plate directly welded on a PCB circuit board, wherein the contact surface of the electrode plate for detection is coated on the outer wall of an infusion tube in a transition fit manner; connection port J3: pin 1 is the input of the power supply; pin 2 is a status signal output; pin 3 is a ground pin. The utility model has the advantages that 1, the utility model is not interfered by various light rays; 2. the device is not limited by the color of the tube body of the infusion tube, and has strong compatibility with different infusion tubes; 3. the influence of the bubbles on the induction capacitance is small, and the influence of the bubbles in the infusion tube can be effectively filtered; 4. the hardware cost is low, and the failure rate is low; 5. the device has extremely low consumption power and is suitable for equipment powered by a battery; 6. the infusion controller is more miniaturized, has better external interference resistance, stronger pipe compatibility and long endurance.

Description

Capacitance induction type liquid detection device of calculation frequency mode

Technical Field

The utility model relates to a capacitance induction type liquid detection device of calculation frequency mode belongs to medical instrument's infusion control class equipment technical field.

Background

The infusion control equipment judges the completion of infusion by detecting whether liquid in an infusion tube exists or not, so that the shutdown and alarm operation are executed, and the liquid detection sensor in the prior art mainly has two types, namely an infrared type and a capacitance type touch IC (integrated circuit), such as an infrared type: CN106345001A, a liquid detection system of a transfusion tube and a detection method thereof; and touch IC formula: CN107569739A, a detection method and device of a capacitive sensor for detecting liquid in an infusion tube; they all have drawbacks in pipe compatibility, interference resistance, volume, cost and power consumption.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to make infusion controller accomplish more miniaturization, better anti external disturbance ability to and stronger tubular product compatibility ability, portable and long duration, thereby provide the electric capacity induction type liquid detection device of a calculation frequency mode.

The technical proposal of the utility model is that the utility model comprises an electrode plate directly welded on a PCB circuit board,

the contact surface of the electrode plate for detection is coated on the outer wall of the infusion tube in a transition fit manner;

the PCB circuit board comprises a singlechip U1 and a singlechip U1LOADThe port P0.3 is pulled up by the resistor R3, and then outputs high level or low level through the combined resistors R1 and R2 to charge or discharge the inductive capacitor on the electrode plate J1, and C1 and C2 are arranged on the electrode plate J1LOADThe port and the VDD port are used for power supply filtering;

of the single-chip microcomputer U1INPort P1.4 detects voltage value of electrode slice J1(ii) a Switching according to voltage valueLOADOutput level of port during chargingINWhen the port detects that the voltage value reaches the high voltage threshold valueLOADSwitching the port to a low level to enter a discharging process; during the discharge process whenINWhen the port detects that the voltage value reaches the low voltage threshold valueLOADSwitching the port to a high level to enter a charging process, and monitoring and recording each charging and discharging period;

the serial port J2 is used for observing different charge-discharge frequency values when liquid exists and liquid does not exist, is used as a reference basis for judging the state in a program, and meanwhile, the J2 can also be used for outputting information for debugging;

connection port J3: pin 1 is the input of the power supply; pin 2 is status signal output; pin 3 is a ground pin.

The technical principle of the utility model lies in that, a timing time is set for to the inside timer of singlechip U1, through the charge-discharge cycle total number that the monitoring obtained in the timing time quantum, calculates current charge-discharge frequency, because the capacitance value that senses when having liquid and having no liquid in the transfer line is different, so the charge-discharge frequency value that obtains is also different, consequently accurately discerns two kinds of states that have or have no liquid to through theOUTPort P1.6 outputs a status signal.

The utility model has the advantages that 1, the anti-interference performance is stronger, and the anti-interference performance is not interfered by various light rays; 2. light detection is not relied on, so that the device is not limited by the color of the tube body of the infusion tube, has strong compatibility with different infusion tubes by 3, has little influence of bubbles on induction capacitance, and can effectively filter the influence of the bubbles in the infusion tube; 4. the circuit is simple and efficient, the hardware cost is low, and the failure rate is low; 5. has extremely low power consumption and is suitable for equipment powered by a battery. 6. The infusion controller is more miniaturized, has better external interference resistance, stronger pipe compatibility and long endurance.

Drawings

Fig. 1 is a schematic view of the structural design of the present invention.

Fig. 2 is a schematic diagram of the circuit design of the present invention.

Fig. 3 is a flow chart of the present invention.

FIG. 4 is a schematic diagram of the periodic charging and discharging of a timer.

Detailed Description

The structure design of the utility model is shown in figure 1, which comprises an electrode plate 2 directly welded on a PCB circuit board 1; the electrode plates 2 should not be too large and should not be connected by wires, and the shape and size of the electrode plates 2 will affect the detection value, so the consistency of the electrode plates should be ensured as much as possible.

The contact surface of the electrode plate 2 for detection is coated on the outer wall of the infusion tube 3 in a transition fit manner; the contact surface of the electrode plate 2 for detection is designed as follows: a square (round) with the side length (diameter) same as or slightly larger than the diameter of the infusion tube 3. The area of the supporting portion of the electrode sheet 2 should not be larger than the detection contact area. When in work, the electrode plate 2 is tightly attached to the outer side wall of a container to be measured (such as an infusion tube or a drip cup) and is well contacted.

The circuit design is shown in figure 2, the PCB circuit board 1 structure comprises a singlechip U1 and a singlechip U1LOADAfter the port P0.3 is pulled up by the resistor R3, the combined resistors R1 and R2 output high level or low level to charge or discharge the inductive capacitor on the electrode plate J1, and the time of the charging and discharging period is adjusted, wherein the larger the resistor is, the longer the period is. The value is recommended to be taken from 1M to 3M, the resistance value is too small, so that the charging and discharging time is too fast, the single chip microcomputer cannot monitor the resistance value, and the anti-interference capability is possibly reduced if the resistance value is too large; r3, C1 and C2 are arranged onLOADThe port and the VDD port are used for power supply filtering; it should be noted that detection values obtained by singlechips of different models under the same circuit parameters may be different, and the consistency of the singlechips should be ensured as much as possible; moreover, the singlechip and the resistor in the circuit are greatly influenced by air humidity, and the electronic components on the circuit board can be locally sealed by 704 organic silicon sealant or the sealant can be completely encapsulated in the mass-produced product; the PCB 1 must be kept clean, and no impurities or soldering flux residue exists, and some impurities or soldering flux have conductivity, so that detection errors occur.

Of the single-chip microcomputer U1INThe port P1.4 detects the voltage value of J1 of the electrode plate 2; switching according to voltage valueLOADOutput level of port during chargingINWhen the port detects that the voltage value reaches the high voltage threshold valueLOADSwitching the port to a low level to enter a discharging process; during the discharge process whenINWhen the port detects that the voltage value reaches the low voltage threshold valueLOADSwitching the port to a high level to enter a charging process, and monitoring and recording each charging and discharging period; a timer in the single chip microcomputer U1 is used for setting a timing time, the current charging and discharging frequency can be calculated by monitoring the total number of the charging and discharging periods in the known timing time and the known timing time, and the obtained charging and discharging frequency value is different because the capacitance values sensed when liquid exists and the capacitance values sensed when no liquid exists, so that the two states of the existence or the absence of the liquid can be accurately identified, and the two states of the existence or the absence of the liquid can be accurately identified by the aid of the timer in the single chip microcomputer U1OUTPort P1.6 outputs a status signal;

the serial port J2 is used for observing different charge-discharge frequency values when liquid exists and liquid does not exist, is used as a reference basis for judging the state in a program, and meanwhile, the J2 can also be used for outputting information for debugging; the infusion tube 3 is preferably installed for adjustment, because the measured value is not stable because the infusion tube 3 is easily affected by the outside. Meanwhile, the infusion tube 3 may cause inner wall contamination after long-time use, and at this time, the liquid may be identified as being present in a liquid-free state; therefore, it is necessary to ensure that the infusion tube 3 is not reused for a long time, and generally, the infusion tube 3 is frequently replaced and reused for actual medical use, and the number of times is small.

Connection port J3: pin 1 is the input of the power supply; pin 2 is a status signal output; pin 3 is a ground pin.

As shown in fig. 3 and 4, the utility model comprises the following steps of firstly, data acquisition, setting a timing time T as a detection period by the internal timer of the single chip microcomputer U1,neach detection period forms a scanning period;

firstly, defining a constant N as a noise coefficient, and sequentially detecting a detection value X obtained in each detection period and a detection value X obtained in a first detection period in a scanning period₁Comparing until the last comparison is finishedA detection value X_nIf the positive and negative difference values of the comparison result are larger than the value of N, the data are regarded as unqualified and directly discarded, the scanning is immediately finished, and the program immediately enters the next scanning period;

step two, detection, namely averaging the scanned group of effective data (the group of effective data is the effective data of one scanning period) to obtain an accurate detection value X ', and dividing the detection value X' by the timing time T set by the timer to obtain a frequency value f; frequency value f in the presence of liquid_aFrequency value in the absence of liquid is f_bThe two frequency values are respectively output through a serial port J2 in a debugging mode, and a preset value D for state judgment can be obtained by averaging the two frequency values: d = (f)_a+f_b)/2；

Step three, comparing, defining a constant S as a sensitivity coefficient, comparing the detection value X 'with a preset value D, judging as a no-liquid state when the detection value X' is larger than D + S, judging as a liquid state when the detection value X 'is smaller than D-S, and keeping the original state when the detection value X' is larger than D-S and smaller than D + S.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The principles and embodiments of the present invention have been explained herein using specific examples, which are presented only to assist in understanding the methods and their core concepts. The foregoing is only a preferred embodiment of the present invention, and it should be noted that there are objectively infinite specific structures due to the limited character expressions, and it will be apparent to those skilled in the art that a plurality of modifications, decorations or changes can be made without departing from the principle of the present invention, and the above technical features can be combined in a proper manner; the application of these modifications, variations or combinations, or the application of the concepts and solutions of the present invention in other contexts without modification, is not intended to be considered as a limitation of the present invention.

Claims (1)

1. A frequency-calculating capacitance-sensitive liquid detecting device, characterized in that:

comprises an electrode plate (2) directly welded on a PCB (1),

the contact surface of the electrode plate (2) for detection is coated on the outer wall of the infusion tube (3) in a transition fit manner;

the PCB circuit board (1) comprises a singlechip U1 and a singlechip U1LOADThe port P0.3 is pulled up by the resistor R3, and then outputs high level or low level through the combined resistors R1 and R2 to charge or discharge the inductive capacitor on the electrode plate J1, and C1 and C2 are arranged on the electrode plate J1LOADThe port and the VDD port are used for power supply filtering;

of the single-chip microcomputer U1INThe port P1.4 detects the voltage value of the electrode plate J1; switching according to voltage valueLOADThe output level of the port monitors and records each charge-discharge period;

the serial port J2 is used for observing different charge-discharge frequency values when liquid exists and liquid does not exist, is used as a reference basis for judging the state in a program, and meanwhile, the J2 can also be used for outputting information for debugging;

connection port J3: pin 1 is the input of the power supply; pin 2 is a status signal output; pin 3 is a ground pin.

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