CN115524059A

CN115524059A - Calibration method and system for pressure acquisition device of human body natural cavity

Info

Publication number: CN115524059A
Application number: CN202211264798.1A
Authority: CN
Inventors: 武理霞; 彭杰; 宋绍方; 孔德润; 付忠谦; 吴艾久
Original assignee: Hefei Zhongna Medical Instrument Co ltd
Current assignee: Hefei Zhongna Medical Instrument Co ltd
Priority date: 2022-10-17
Filing date: 2022-10-17
Publication date: 2022-12-27

Abstract

The invention relates to a calibration method and a system for a pressure acquisition device of a human natural cavity. The calibration method comprises the following steps: s1: at P ₀ Real-time air pressure value P of pressure acquisition device under environment _i So that the volume of the pressure acquisition device reaches V _d (ii) a S2: placing the pressure acquisition device at a temperature T ₁ Pressure of P ₀ The sealed container (2); s3: injecting quantitative air into the sealed container every time, and measuring average air pressure P of the sealed container _ni Read P _i (ii) a S4: when P is present _ni ≥P _max While, adjust the calibration temperature high and P _ni Is restored to P ₀ According to a plurality of P at the same time _ni And P _i Constructing a correction function and a compensation function; s5: repeating the step S4 until the temperature of the closed container reaches T _max And performing parameter correction on the pressure acquisition device according to the plurality of built correction functions and the compensation function. The invention eliminates the error caused by the performance of the pressure acquisition device, accurately corrects the pressure acquisition device and meets the measurement precision requirement of the pressure acquisition device.

Description

Calibration method and system for pressure acquisition device of human body natural cavity

Technical Field

The invention relates to a pressure acquisition device, in particular to a calibration method and a calibration system for the pressure acquisition device of a natural human body cavity.

Background

In the medical operation process, the health state of corresponding organs or tissues can be judged by detecting the pressure of natural cavities or tissue gaps of a human body. For example, the intraocular pressure is generally 10mmHg-21mmHg, the cerebral perfusion pressure is generally 70mmHg-100mmHg, and the bladder pressure is generally not higher than 40cmH2O (about 29.4 mmHg).

The existing pressure acquisition devices for measuring natural orifices or tissue gaps of human bodies comprise contact pressure acquisition devices and non-contact pressure acquisition devices. When the non-contact pressure acquisition device is used for measurement, the measurement result is interfered by liquid (such as blood, tissue effusion and aqueous humor in eyes) or cavity air and the like in a human body, and the actually measured pressure value has larger error. When the contact pressure acquisition device is used for measurement, the difference between the internal environment and the external air environment causes errors to the measurement result, so that the measurement precision is low. And because the difference between the measurement environment of the natural cavity or tissue gap of the human body and the air environment is large, the pressure acquisition device is difficult to accurately correct by adopting the conventional calibration method.

Disclosure of Invention

Therefore, it is necessary to provide a calibration method for a pressure acquisition device used in a natural body lumen, which aims at the problem that the calibration accuracy of the existing pressure acquisition device used in a body lumen or a tissue gap is low.

The invention is realized by the following technical scheme: a calibration method of a pressure acquisition device for a natural cavity of a human body is used for detecting an air pressure value displayed by the pressure acquisition device in real time, an error between an actual air pressure value of a region to be detected and an actual air pressure value of an inner cavity of the pressure acquisition device, and then correcting the pressure acquisition device to reduce or eliminate the error.

The pressure acquisition device comprises a probe, an air pipe, an air storage pipe and an optical fiber pressure sensor. A detection cavity is arranged in the probe, and an air storage chamber is arranged in the air storage pipe. The probe comprises an annular rigid body and an elastic film. The elastic film covers the annular rigid body, and the annular rigid body and the elastic film jointly enclose a detection cavity. When the internal pressure and the external pressure of the probe are different, the elastic film deforms under the action of the internal pressure and the external pressure so that the internal pressure and the external pressure of the probe tend to be consistent. Therefore, the pressure of the detection cavity can be directly measured to serve as the pressure value of the area to be measured only by guiding the probe into the area to be measured. The detection cavity is communicated with the air storage chamber through an air pipe. The detection cavity is formed by the detection cavity, the air pipe inner cavity and the air storage chamber. The detection cavity is a closed cavity, and the air pressure value at any position in the detection cavity is the same. The optical fiber pressure sensor is arranged in the air storage chamber and used for detecting the air pressure in the air storage chamber. The air pressure of the air storage chamber is measured through the optical fiber pressure sensor, and the air pressure can be used as the air pressure of the detection cavity, namely the actual pressure value of the area to be measured.

The calibration method comprises the following steps:

s1: and vacuumizing the pressure acquisition device until the air pressure of a detection cavity of the pressure acquisition device is lower than a preset threshold value. At a pressure value of P ₀ Under the constant pressure environment, air is injected into the detection cavity until the real-time air pressure value displayed by the optical fiber pressure sensor is kept unchanged, and the real-time air pressure value P displayed by the optical fiber pressure sensor at the moment is recorded ₁ . And continuously injecting air into the detection cavity until the real-time air pressure value displayed by the optical fiber pressure sensor just changes.

S2: setting the calibration temperature range to [ T ] ₁ ，T _max ]. Setting the calibrated pressure range to [ P ] ₀ ，P _max ]. Placing pressure acquisition devices in oneAverage temperature of T ₁ In the constant-temperature closed container. Injecting or exhausting gas into the closed container until the average gas pressure in the closed container is P ₀ 。

S3: each injection of n into the closed container ₁ Adjusting the average air pressure in the sealed container by mol air, and measuring the average air pressure P in the sealed container in real time _ni . Reading real-time air pressure value P displayed by optical fiber pressure sensor _i 。

S4: determining the average pressure P _ni Whether or not higher than P _max If yes, the average temperature in the closed container is increased by delta T, and the closed container is exhausted to ensure that the average air pressure P is increased _ni Is restored to P ₀ . According to a plurality of acquired average air pressures P simultaneously _ni And corresponding real-time barometric pressure value P _i And adopting a curve fitting method to construct a correction function and a compensation function under the current temperature condition. Correction function characterizing ideal air pressure P _hi And real-time air pressure value P _i The mapping relationship between them. The compensation function characterizes the ideal pressure P _hi And average gas pressure P _ni The mapping relationship between them. Otherwise, repeating the step S3 until the average air pressure P _ni Higher than P _max . The construction method of the correction function comprises the following steps:

s41: according to each average air pressure P _ni And total volume V of pressure acquisition device _d Calculating the ideal air pressure P of the pressure acquisition device _hi 。

S42: a plurality of real-time air pressure values P are collected _i A plurality of corresponding ideal air pressure values P _hi Mapping to a plane coordinate system to obtain a plurality of coordinate points A _i 。

S43: for a plurality of coordinate points A _i Performing curve fitting to obtain fitted curve function R _fi As a correction function.

The method for obtaining the offset function comprises the following steps:

s44: a plurality of average pressures P to be collected _ni And a plurality of corresponding desired air pressure values P _hi Mapping to another plane coordinate system to obtain multiple coordinate points B _i 。

S45: for a plurality of coordinate points B _i Performing curve fitting to obtain a fitted curve function P _f As a function of the offset.

S5: judging whether the average temperature in the closed container reaches T _max If so, based on the fitted plurality of correction functions R _fi And correcting parameters of the optical fiber pressure sensor. The corrected optical fiber pressure sensor displays the measured inner cavity air pressure in real time, and displays the actual air pressure value of the area to be measured according to a plurality of compensation functions. Otherwise, repeating the step S4 until the average temperature in the closed container reaches T _max 。

According to the calibration method, the pressure acquisition device is vacuumized, and then gas is injected into the pressure acquisition device, so that the pressure acquisition device reaches the maximum volume within the measuring range of the pressure acquisition device, and calibration errors caused by volume changes of the pressure acquisition device are eliminated. And then, acquiring real-time air pressure values displayed by the pressure acquisition device and the average air pressure of the closed container in different temperature and different air pressure environments, further calculating corresponding ideal air pressure according to the volume of the closed container, the total volume of the pressure acquisition device and the total volume of the pressure acquisition device, further constructing a correction function according to a mapping relation between the ideal air pressure and the actual air pressure value, and performing parameter correction on the optical fiber pressure sensor of the pressure acquisition device so as to enable the measurement precision of the optical fiber pressure sensor to meet the measurement requirement. And finally, constructing a compensation function according to the mapping relation between the measured average air pressure and the ideal air pressure so as to reduce and eliminate errors generated by the performance of the pressure acquisition device, improve the measurement precision in actual measurement and meet the precision requirement of pressure detection of the pressure acquisition device in a natural cavity or tissue gap of a human body.

In one embodiment, when the average air pressure of the closed container reaches just P ₀ Judging whether the real-time air pressure value displayed by the optical fiber pressure sensor is also P ₀ If yes, the calibration is continued. Otherwise, synchronously regulating the average air pressure in the closed container and the air pressure in the detection cavity until the average air pressure P _ni And the air pressure value P _i Are all P ₀ 。。

In one embodiment, the amount of air injected per injection is calculated by:

s31: according to the current temperature of the closed container and the initial air pressure P of the closed container ₀ Volume V of the sealed container _c And initial total volume V of pressure acquisition device _d Calculating the quantity n of the initial substance of the air in the closed container ₀ . Then n is ₀ Expressed as:

n ₀ ＝P ₀ (V _c -V _d )/RT ₁

wherein n is ₀ Amount of starting material, V, of gas in a closed container _c Is the volume of the closed container, V _d Is the initial total volume of the pressure acquisition device, T ₁ Is the initial temperature.

S32: calculating the mass n of air injected each time according to the expected air pressure difference delta P ₁ Then n is ₁ Expressed as:

n ₁ ＝ΔPn ₀ /P ₀

where Δ P is the air pressure value at which the average air pressure in the closed container is expected to be adjusted during calibration.

In one embodiment, the desired pressure P _hi Expressed as:

wherein n is ₀ Is the amount of material, T, of the gas in the pressure acquisition unit _j Is ambient temperature, V ₀ Is the initial total volume of the pressure acquisition device, Δ V is the variable of the total volume of the pressure acquisition device, m is the total number of times of gas injection into the closed container, n _i The quantity of material, P, of air at the time of the ith measurement of the closed container _ai Average pressure, V, measured for the ith time of the closed vessel _c Is the total volume of the closed container, V _d Is the total volume of the pressure acquisition device.

In one embodiment, the amount of material n of the gas within the pressure acquisition device _d Expressed as:

n _d ＝P ₀ V ₀ /RT ₁

quantity n of substance in air in closed container at the time of ith measurement _i Expressed as:

n _i ＝n ₀ +(i-1)n ₁ 。

in one embodiment, the correction function R _fi Expressed as:

wherein, P _i Air pressure value, P, displayed in real time for pressure acquisition means _c To correct the base value, k _j Is the correction factor after the j-th tempering, k _j+1 Is the correction coefficient k after the j +1 th temperature adjustment ₁ The correction coefficient is a correction coefficient at a temperature T1.

In one embodiment, the offset function is expressed as:

P _f ＝ε+K _j P _i

wherein, P _f Is the actual air pressure value of the area to be measured, epsilon is an interference factor, K _j To compensate for the coefficient under different temperature conditions.

The invention also provides a calibration system of the pressure acquisition device for the natural orifice of the human body, which comprises a closed container, an air pump, an air pressure detection device, a temperature control device, a processor and a parameter setting device.

The closed container is used for accommodating the pressure acquisition device. The closed vessel is also used to provide a constant temperature environment for the calibration process. The valve is communicated with the closed container and used for controlling the communication state of the closed container and air.

One end of the air pump is communicated with the valve of the closed container, and the other end of the air pump is communicated with the air. The air pump is used for adjusting the air pressure in the closed container. The air pressure detection device is used for monitoring the average air pressure in the closed container in real time. The temperature control device is used for adjusting the average temperature of the closed container.

In one embodiment, the processor is configured to: a. and obtaining ideal air pressure in a conversion table according to the average air pressure acquired in real time, wherein the conversion table represents the mapping relation between the average air pressure and the ideal air pressure. b. And calculating the mapping relation between the ideal air pressure and the real-time air pressure value according to the plurality of calculated ideal air pressures and the plurality of real-time air pressure values measured by the pressure acquisition device in real time. c. And calculating the mapping relation between the real-time air pressure value measured by the pressure acquisition device and the actual air pressure of the position to be measured according to the measured average air pressure and the corresponding ideal air pressure.

In one embodiment, the parameter setting device is configured to set a parameter of the pressure acquisition device according to a mapping relationship between the ideal air pressure and the real-time air pressure value, so that an error between the real-time air pressure value measured by the pressure acquisition device and an actual air pressure value of the position to be measured does not exceed a preset error range.

Compared with the prior art, the invention has the following beneficial effects:

1. the calibration method comprises the steps of vacuumizing the pressure acquisition device, and injecting gas into the pressure acquisition device, so that the pressure acquisition device reaches the maximum volume in the measuring range, and the calibration error caused by the volume change of the pressure acquisition device is eliminated. And then, acquiring real-time air pressure values displayed by the pressure acquisition device and the average air pressure of the closed container under different temperatures and different air pressure environments, further calculating corresponding ideal air pressure according to the volume of the closed container, the total volume of the pressure acquisition device and the total volume of the pressure acquisition device, further constructing a correction function according to a mapping relation between the ideal air pressure and the actual air pressure value, and performing parameter correction on an optical fiber pressure sensor of the pressure acquisition device so as to enable the measurement precision of the optical fiber pressure sensor to meet the measurement requirement. And finally, constructing a compensation function according to the mapping relation between the measured average air pressure and the ideal air pressure so as to reduce and eliminate errors caused by the performance of the pressure acquisition device, improve the measurement precision in actual measurement and meet the precision requirement of pressure detection of the pressure acquisition device in a natural cavity or a tissue gap of a human body.

Drawings

Fig. 1 is a schematic front sectional view of a pressure collecting device for natural body lumens or tissue gaps according to embodiment 1 of the present invention;

FIG. 2 is a schematic side view of the probe of FIG. 1 shown without insufflation;

FIG. 3 is a schematic side view of the probe of FIG. 1 after pre-injection molding;

FIG. 4 is a schematic perspective view of the annular rigid body in FIG. 1;

FIG. 5 is a flowchart of a calibration method of a pressure acquisition device for a natural orifice of a human body according to embodiment 2 of the present invention;

FIG. 6 is a schematic cross-sectional view of a calibration system of a pressure acquisition device for a natural orifice of a human body according to embodiment 3 of the present invention;

fig. 7 is a schematic structural diagram of a frame of the calibration system of the pressure acquisition device for the natural orifice of the human body in fig. 6.

Description of the main elements

The reference numbers in the figures are: 1. a probe; 11. an annular rod body; 12. an elastic film; 2. an air tube; 3. a luer fitting; 4. a gas storage pipe; 5. a check valve assembly; 51. a spring; 52. a guide rail; 53. a valve core; 6. a piston assembly; 61. a piston; 62. a connecting rod; 63. a push block; 7. a fiber optic pressure sensor; 8. a handle; 9. sealing sleeves; 10. a pressure acquisition device; 20. a closed container; 30. an air pressure detecting device; 40. an air pump; 50. a temperature control device; A. a probe chamber; B. the trachea lumen; C. an air storage chamber; D. injecting air into the air chamber; E. a second through hole; F. an air inlet; G. and a first through hole.

The present invention is described in further detail with reference to the drawings and the detailed description.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It will be understood that when an element is referred to as being "mounted on" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. When an element is referred to as being "secured to" another element, it can be directly secured to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Example 1

Please refer to fig. 1, which is a schematic sectional view of a front view of a pressure collecting device for natural body lumens or tissue gaps according to embodiment 1 of the present invention. A pressure acquisition device for human natural orifice or tissue gap includes: the probe 1, the air pipe 2, the air storage pipe 4, the optical fiber pressure sensor 7, the piston assembly 6, the handle 8, the sealing sleeve 9, a processor not shown and a display not shown.

Referring to FIGS. 2, 3 and 4, FIG. 2 is a schematic side view of the probe of FIG. 1 when the probe is not inflated; FIG. 3 is a schematic side view of the probe of FIG. 1 after pre-injection molding; fig. 4 is a schematic perspective view of the annular rigid body in fig. 1. The probe 1 includes an annular rigid body 11 and an elastic thin film 12. The elastic film 12 is coated on the outer surface of the annular rigid body 11, and the elastic film 12 and the annular rigid body 11 jointly enclose a detection cavity A. One end of the annular rigid body 11 is fixedly connected with one end of the air pipe 2, and a through hole G for communicating the detection cavity A with the air pipe 2 is formed in the annular rigid body 11. The thickness of one side of the annular rigid body 11 connected with the trachea 2 is larger than that of the other side of the annular rigid body 11.

When no gas is injected into the detection cavity A, the top surface of the probe 1 is circular and the side surface of the probe 1 is wedge-shaped. When a certain amount of gas is injected into the detection cavity A, the whole probe 1 is in an ellipsoid shape. When the pressure of the human body cavity or the tissue gap is actually measured, one end of the probe 1, which is far away from the trachea 2, is used as the front end and is used for guiding the trachea 2 to penetrate into the human body cavity or the tissue gap. The gas is injected into the detection cavity A to enable the elastic film 12 to bulge outwards, so that the human tissue is in flexible contact with the probe 1, and the human tissue is prevented from being damaged. When the pressure in the detection cavity A is different from the pressure in the external environment, the elastic film 12 deforms to change the volume of the gas in the detection cavity A, and then the pressure in the detection cavity A is adjusted to enable the pressure in the detection cavity A to be consistent with the pressure in the external environment.

The annular rigid body 11 may be made of metal, wooden, polymer or ceramic, and the like, as long as it does not deform during detection within the range of the pressure acquisition device. The elastic film 12 may be made of a rubber material or other high elastic material having reversibility. In this embodiment, the annular rigid body 11 made of stainless steel and the elastic film 12 made of latex are used. The stainless steel material has the characteristics of high hardness, strong corrosion resistance and the like, and can meet the requirement of long-term use. The latex material has the characteristics of high flexibility, environmental protection and no pollution, and is harmless to human bodies.

In other embodiments, the annular rigid body 11 may be replaced by a hollow wedge, a hollow ellipsoid, a hollow sphere, or a hollow cone, etc., as long as the elastic film 12 and the detection cavity a can be formed together, and the elastic film 12 can be freely deformed in the inner and outer directions of the detection cavity a. The end of the annular rigid body 11 far away from the trachea 2 is a tip, and the tip of the annular rigid body 11 is a front end and is used for guiding the probe 1 to penetrate into a natural cavity or a tissue gap of a human body. When the elastic film 12 protrudes outwards to reach the filling state, the radial section of the probe 1 at any position is circular or nearly circular, and the probe 1 is in flexible contact with human tissues when being guided into a natural orifice or a tissue gap of a human body, so that the human body can be prevented from being injured.

During actual measurement, when the pressure of the natural cavity or tissue gap of the human body is inconsistent with the air pressure in the detection cavity a, the elastic film 12 of the probe 1 is deformed under the action of pressure difference, so that the internal and external pressures of the probe 1 are consistent, namely, the air pressure value in the detection cavity a is consistent with the pressure value of the area to be detected. Therefore, the actual pressure value of the area to be detected can be obtained only by detecting the air pressure in the detection cavity A. In this embodiment, will survey chamber A and gas receiver 4 intercommunication and form inclosed detection chamber, and then only need measure the atmospheric pressure in the gas receiver 4 and can regard as the actual pressure value of waiting to detect the region.

The air pipe 2 is a hose, and when the air pipe 2 deforms, the change rate of the total volume of the air pipe 2 is lower than a preset error range. In the present embodiment, the predetermined error range is [ -0.01,0.01]. The air pipe 2 can be detachably connected with the air storage pipe 4 through a luer connector 3. The gas pipe 2 can be made of metal pipe, plastic pipe, etc. The air pipe 2 is used for prolonging the distance between the probe 1 and the air storage pipe 4, so that when the probe 1 is inserted into a natural cavity or a tissue gap of a human body, the air storage pipe 4 is positioned outside the human body. In actual measurement, different lengths and different materials of the trachea 2 can be selected according to the position of a specific measured cavity or tissue gap. In this embodiment, a memory metal hose is adopted, and the total volume of the memory metal hose and the air storage chamber C is smaller than the total volume of the detection cavity a. The memory metal material has high flexibility, can freely move in irregular human body cavities or tissue gaps, and has almost no change of the volume of an inner cavity under the integral bending state, and almost no influence on a measurement result.

When the natural cavity or tissue gap of the human body to be measured can be guided in a straight line from the outside, the trachea 2 can also adopt a rigid pipeline, such as a stainless steel pipe.

The luer connector 3 is a standardized micro non-seepage connector, and the air pipe 2 is hermetically connected with the air storage pipe 4 through the male luer connector 3 and the matched female luer connector 3. Luer connector 3 is convenient for install and dismantle, and through the dismouting of public female luer connector 3, is convenient for discharge the gas in gas storage tube 4 or probe 1.

The air storage pipe 4 is internally provided with an air storage chamber C and an air injection chamber D. The air storage chamber C is communicated with the other end of the air pipe 2, and then the air storage chamber C is communicated with the detection cavity A. One end of the air injection chamber D is communicated with the air storage chamber C through a through hole II E. The other end of the air injection chamber D is communicated with the air through an air inlet hole F. The air storage chamber C, the air pipe inner cavity B and the detection cavity A are communicated with each other and form a detection cavity together, and the air pressure value at each position in the detection cavity is equal.

The optical fiber pressure sensor 7 is installed in the air storage chamber C. The optical fiber pressure sensor 7 is used for detecting the air pressure in the air storage chamber C. The fiber optic pressure sensor 7 is a fiber optic sensor with pressure sensitive elements, and the fiber optic pressure sensor 7 generally includes several types, depending on the measurement principle: a microbend type optical fiber pressure sensor, a transmission type optical fiber pressure sensor, a reflection type optical fiber pressure sensor, a frequency modulation optical fiber pressure sensor, a Mach-Zehnder interference type optical fiber pressure sensor, a grating optical fiber pressure sensor, a distributed optical fiber pressure sensor, and the like. In the embodiment, the grating optical fiber pressure sensor is adopted, and the measurement principle is as follows: the fiber Bragg grating is attached to the deformable body, when pressure is applied to a measured object, the deformable body deforms under the action of external pressure, the effective refractive index and the fiber period of the fiber grating change, broadband light emitted by the light source is reflected by the deformed fiber grating, bragg wavelength shifts, the spectrum of the reflected light is measured through the spectrometer, and the measured pressure is obtained. The grating optical fiber pressure sensor has the characteristics of high precision, high wide-range measurement resolution, strong anti-interference capability and the like, and has higher measurement precision on the cavity pressure.

In other embodiments, the fiber optic pressure sensor 7 may be replaced by other pressure sensors, such as a piezoresistive pressure sensor, a piezoelectric pressure sensor, or a capacitive pressure sensor.

The check valve assembly 5 is arranged in the air storage chamber C and used for controlling the on-off state of the second through hole E. The check valve assembly 5 includes a spool 53, a spring 51, and a guide rail 52. The guide rail 52 is fixedly connected in the air storage chamber C, and the position of the guide rail 52 is opposite to the position E of the through hole II. One end of the spring 51 is fixedly mounted on the guide rail 52. The other end of the spring 51 is fixedly connected with the valve core 53, so that the valve core 53 covers the second through hole E. When the pressure of the air pressure in the air injection chamber D on the valve core 53 is smaller than the elastic force of the spring 51 on the valve core 53, the valve core 53 covers the through hole II E, and the air storage chamber C, the air pipe 2 and the detection cavity A form a sealed space.

In other embodiments, the spring 51 may also be directly connected between the valve core 53 and the inner wall of the air reservoir C, as long as the valve core 53 is covered on the second through hole E. The valve core 53 can also be provided with a guide rod which is connected in the second through hole E in a sliding manner, and the inner diameter of the guide rod is smaller than that of the second through hole E. When gas is injected into the gas storage chamber C through the second through hole E, the driving force of the gas pressure of the injected gas on the valve core 53 is greater than the elastic force of the spring 51, so that the valve core 53 is far away from the second through hole E, and the spring 51 contracts inwards. When gas is injected into the gas storage chamber C, the gas pressure inside and outside the gas storage chamber C tends to be consistent, the valve core 53 is reset by the elastic force of the spring 51 and covers the through hole II.

The check valve assembly 5 may also be directly provided with a resilient hemispherical valve core 53. One end of the hemispherical valve core 53 is fixedly connected to the inner wall of the air storage chamber C, and under the action of elastic force, the hemispherical valve core 53 covers the second through hole E. The hemispherical valve core 53 is tightly covered with the second through hole E, so that the sealing performance of the air storage chamber C can be improved.

The piston assembly and the gas injection chamber D jointly form a gas injection device. The gas injection device is used for injecting gas into the gas storage chamber C, and then adjusting the gas pressure in the gas storage chamber C. The piston assembly 6 includes a piston 61, a connecting rod 62, and a push block 63. The piston 61 is slidably connected in the gas injection chamber D, and the piston 61 is attached to the inner wall of the gas injection chamber D. One end of the connecting rod 62 is fixedly connected with the piston 61, and the other end of the connecting rod 62 passes through the gas storage pipe 4 and is fixedly connected with the push block 63.

The operator pushes the push block 63, so that the piston 61 is driven to slide in the gas injection chamber D, and when the piston 61 approaches to the second through hole E until the piston is positioned between the second through hole E and the gas inlet hole F, the piston 61 divides the gas injection chamber D into a closed cavity close to the second through hole E and a communication cavity far away from the second through hole E. When the piston 61 continues to move towards the second through hole E, the air in the closed cavity is compressed, the air pressure in the closed cavity is rapidly increased, the driving force of the air pressure in the closed cavity to the valve core 53 is further made to be larger than the elastic force of the spring 51 to the valve core 53, the second through hole E is further opened, and part of air is injected into the air storage chamber C. At this time, the air reservoir C communicates with the closed chamber and has the same air pressure, so that the valve core 53 is covered on the second through hole E again by the elastic force of the spring 51. The push block 63 is pulled back, the volume of the closed cavity is increased, and the air pressure is reduced. And continuously pulling back the push block 63 until the closed cavity is communicated with the air inlet hole F, and supplementing air into the closed cavity under the action of air pressure difference. The air can be continuously injected into the air storage chamber C by repeatedly pushing the push block 63.

Of course, in other embodiments, an electric air pump, a high pressure air cylinder, an air pump, etc. may be used as the piston assembly 6. Compared with manual gas injection, the electric inflator and the air pump have the advantages of being high in inflation speed, controllable in inflation speed and the like, electric energy needs to be consumed additionally, and the device is large in size, large in mass and not easy to install. The high-pressure air cylinder is also a manually operated piston assembly 6, has the characteristic of labor saving, but is also large in size and difficult to install.

The measurement method of the pressure acquisition device provided by the embodiment specifically includes the following steps:

first, the pressure acquisition device is pre-filled to bulge the elastic membrane 12 outward to an inflated state. The concrete method of pre-injection is as follows: gas is injected into the gas storage chamber C through the piston assembly 6, after the real-time pressure value displayed by the pressure acquisition device does not change, whether the elastic film 12 is full or not is observed, and the gas injection is stopped when the elastic film 12 is in a full state.

Secondly, the probe 1 is guided into the natural cavity or tissue gap of the human body to be measured through a guiding device or directly through the trachea 2. When the air pressure in the detection cavity A is different from the pressure of the natural cavity or tissue gap of the human body, the elastic film 12 is deformed under the action of the pressure difference, so that the volume of the detection cavity A is changed, the air pressure in the detection cavity A is enabled to be consistent with the pressure of the natural cavity or tissue gap of the human body, and the air pressure value measured by the optical fiber pressure sensor 7 is directly read to serve as the actual pressure value of the natural cavity or tissue gap of the human body.

In order to improve the accuracy of measurement, the pressure value of the pre-injection pressure can be set to 10mmHg. Then, under the constant pressure environment with the air pressure value of 10mmHg, gas is injected into the gas storage chamber C through the piston assembly 6, so that the real-time air pressure value displayed by the pressure acquisition device is 10mmHg. In the actual measurement, 10mmHg is used as a zero reference point, and finally measured data can be converted into an actual measurement value through a preset formula.

The handle 8 is wrapped around the gas storage tube 4. The handle 8 is provided with a sliding groove for the pushing block 63 to slide. In the process of pre-injection, an operator holds the handle 8 by hand and pushes and pulls the push block 63 by hand to realize the gas injection operation of the gas storage chamber C. The handle 8 may be a plastic, wooden, rubber, or the like. In the embodiment, the plastic handle 8 is adopted, so that the weight is light, the hardness is high, the operation is convenient, and the manufacturing cost can be reduced.

The sealing sleeve 9 is sleeved on the optical fiber pressure sensor 7 to realize the sealing between the optical fiber pressure sensor 7 and the air storage chamber C. One end of the optical fiber pressure sensor 7 is positioned in the air storage chamber C, and the other end of the optical fiber pressure sensor passes through the air storage pipe 4. The sealing sleeve 9 is fixedly connected to the outer side of the optical fiber pressure sensor 7, and the outer wall of the sealing sleeve 9 is tightly attached to the inner wall of the air storage chamber C. The sealing sleeve 9 can be made of nitrile rubber, fluororubber or the like as a rubber material, or polytetrafluoroethylene, nylon or the like as a plastic material, or can be made of a metal material. The nitrile rubber is adopted in the embodiment, so that the sealing performance is high, the disassembly and the assembly are convenient, and the overhaul of the pressure acquisition device is facilitated.

The processor is communicated with the optical fiber pressure sensor 7 through an optical fiber lead. The processor is used for calculating the air pressure in the air storage chamber C according to the pressure signal transmitted by the optical fiber pressure sensor 7. The optical fiber pressure sensor 7 is deformed by the stress of the sensitive element, so that the change of the optical signal is converted into an electric signal, the electric signal is analyzed to obtain an actual pressure value, and a corresponding pressure value is obtained according to a prestored conversion formula or a conversion table. The optical fiber pressure sensor 7 can only display the pressure value, and the processor is used for converting the pressure value into a corresponding air pressure value and then converting the air pressure value into an actual pressure value of the area to be detected. Of course, the optical fiber pressure sensor 7 may also be used only as a pressure sensing and signal transmission tool, and the processor may complete conversion of optical signals and analysis of electrical signals, so as to obtain corresponding pressure values and air pressure values.

The processor may also correct the actual pressure value based on the tension change of the elastic membrane 12 when calculating the actual pressure value. According to the material of the elastic film 12, the actual tension of the elastic film 12 under different stress conditions is calculated, and further, the error caused by the tension change is eliminated in the actual measurement, so that the actual measurement precision of the pressure acquisition device is improved.

The display is communicated with the processor and is used for displaying the measured pressure value in real time. The display can be an electronic display screen, a mobile phone, a liquid crystal display screen or other intelligent display screens and the like. The display can be directly installed on the pressure acquisition device, and can also display the pressure value measured in real time through remote connection.

The pressure acquisition device provided by the embodiment can also be applied to pressure measurement in other animals or pressure measurement of other small-sized tunnels. For example, when an operation is performed on an animal, the pressure in the animal can be measured directly by the optical fiber pressure sensor 7 in the same manner as the internal pressure of the human body, i.e., by introducing the probe 1 into the animal.

When other small-sized pore canals are measured, a hollowed-out spherical protective support can be added on the outer side of the probe 1 so as to prevent the elastic film 12 from being scratched when the elastic film penetrates into the pore canals. The inner diameter of the spherical protective bracket should be larger than the maximum inner diameter of the elastic membrane 12 in the measuring range so as to avoid interference on the actual measurement result.

Example 2

Before the pressure acquisition device in embodiment 1 performs actual pressure detection, the pressure acquisition device needs to be calibrated, so that an error between a pressure value measured by the pressure acquisition device and an actual pressure value is not higher than a preset threshold range, and the accuracy of the pressure acquisition device in the actual measurement is further improved.

Please refer to fig. 5, which is a flowchart illustrating a calibration method of the pressure collecting device for a natural orifice of a human body according to the present embodiment. The embodiment provides a calibration method of a pressure acquisition device, which comprises the following steps:

Because the pressure acquisition device is in the range (in the embodiment, the range of the pressure acquisition device is 10-100 mmHg), the volume of the probe is automatically adjusted under the action of the internal and external air pressure difference, so that the internal and external air pressures of the probe tend to be consistent. Therefore, when the pressure in the channel is collected and pre-injected, the pressure collecting device may be first evacuated to make the pressure in the detection cavity far lower than the measurement range (in this embodiment, the pressure in the detection cavity after evacuation is lower than 0.1 mmHg), and at this time, the volume of the probe is reduced to the minimum state (the elastic film is recessed inwards until part of the elastic film is attached). Of course, in other embodiments, the evacuation or vacuum may be performed in an environment (e.g., 5 mmHg) with a pressure value lower than that of the pressure acquisition device until the elastic membrane begins to collapse inward.

When air is injected into the vacuumized pressure acquisition device, the real-time air pressure value displayed by the optical fiber pressure sensor is gradually increased until the real-time air pressure value approaches to P ₀ . After air is continuously injected, the real-time air pressure value displayed by the optical fiber pressure sensor is kept unchanged and then is slowly increased. Recording the real-time air pressure value P displayed by the optical fiber sensor at the moment ₁ . In this embodiment, it is necessary to keep the real-time air pressure equal to P ₁ On the premise of (1), more air is injected as much as possible, so that the pressure acquisition device reaches the maximum volume within the range, and further the calibration condition is met.

S2: setting the calibration temperature range to [ T ] ₁ ，T _max ]. Setting the calibrated pressure range to [ P ] ₀ ，P _max ]. Placing the pressure acquisition device at an average temperature T ₁ In the constant-temperature closed container. Injecting or exhausting air into or out of the closed container until the average air pressure in the closed container is P ₀ 。

According to the requirement of calibration accuracy, the temperature variable delta T and the air pressure variable delta P of each calibration can be set. In order to calculate the ideal air pressure of the pressure acquisition device, the amount of air to be injected at each time may be calculated from the air pressure variable Δ P, and the average air pressure in the closed container may be adjusted by injecting a predetermined amount of air into the closed container.

The air pressure value in the closed container also reaches P ₀ The real-time air pressure value displayed by the optical fiber pressure sensor is kept at P ₁ And the total volume of the optical fiber pressure sensor is unchanged, so that the error of the actual calibration result caused by the volume change caused by the pressure difference can be eliminated.

In the present embodiment, the calibration temperature range (i.e., the temperature range of the closed vessel) is set to [0 ℃,50 DEG C]The calibration pressure range (i.e., the pressure range of the closed vessel) was set to [5mmHg]. Although the body temperature of a human body is generally 36-37.5 ℃, the calibration temperature range is expanded by considering the application of the pressure acquisition device in different environments (such as pressure detection in an animal body and the like). Meanwhile, the tension of the elastic film is not obviously changed in the measuring range, so that the measuring accuracy is improved. In consideration of the measurement accuracy of the pressure acquisition device, Δ T was set to 5 ℃, and Δ P was set to 5mmHg. Then in the calibration process, 11 sets of calibration data should be obtained, and each set of calibration data includes at least 21 average air pressures P _ni And corresponding real-time barometric pressure value P _i 。

S3: each time of injecting n into the closed container ₁ Adjusting the average air pressure in the sealed container by mol air, and measuring the average air pressure P in the sealed container in real time _ni . Reading real-time air pressure value P displayed by optical fiber pressure sensor _i . The average air pressure in the closed container is uniformly increased by injecting the same amount of air into the closed container every time until the air pressure reaches or exceeds the calibration air pressure range. The method of quantitatively injecting air is adopted, so that the calculation process can be simplified, the ideal air pressure value in the pressure acquisition device can be conveniently calculated, the calibration accuracy can be improved, and the measurement error caused by overlarge air pressure change rate can be reduced or eliminated.

The amount of air injected per time was calculated by the following method:

s31: according to the current temperature of the closed container and the initial air pressure P of the closed container ₀ Volume V of the sealed container _c And initial total volume V of pressure acquisition device _d In a sealed container for calculationAmount n of starting material of air ₀ 。

The general calculation formula for gas pressure is:

PV＝nRT

wherein P is gas pressure, V is gas volume, n is amount of substance, R is universal gas constant, and T is temperature.

Then n is ₀ Expressed as:

n ₀ ＝P ₀ (V _c -V _d )/RT ₁

S32: calculating the mass n of air injected each time according to the expected air pressure difference delta P ₁ Because the temperature of the closed container is not changed, on the premise of not considering the change of the total volume of the gas of the closed container, the following steps are provided:

n ₁ /n ₀ ＝ΔP/P ₀

then n is ₁ Expressed as:

n ₁ ＝ΔPn ₀ /P ₀

In the actual calibration process, the air pressure of the pressure acquisition device is increased along with the increase of the air pressure of the closed container, so that the total volume of the pressure acquisition device is reduced. The total volume of the gas in the closed container becomes large and the variation of the actual average gas pressure of the closed container is lower than the preset expected gas pressure difference Δ P.

S4: determining the average pressure P _ni Whether or not higher than P _max If yes, the average temperature in the closed container is increased by delta T, and the closed container is exhausted to ensure that the average air pressure P is increased _ni Is restored to P ₀ . According to a plurality of average air pressures P obtained simultaneously _ni And corresponding real-time barometric pressure value P _i And adopting a curve fitting method to construct a correction function and a compensation function under the current temperature condition. Repair thePositive function characterization of ideal air pressure P _hi And real-time air pressure value P _i The mapping relationship between them. Characterization of ideal pressure P by a compensation function _hi And average gas pressure P _ni The mapping relationship between them. Otherwise, repeating the step S3 until the average air pressure P _ni Higher than P _max 。

When the average pressure P of the closed container _ni Higher than P _max And then, the data required by calibration is acquired at the current temperature, and the calibration data at the next temperature can be acquired. And calculating the mapping relation between the average air pressure and the real-time air pressure value at the current temperature according to the acquired average air pressure and the real-time air pressure value. In consideration of the measurement accuracy of the optical fiber pressure sensor, the embodiment calculates the ideal air pressure value of the pressure acquisition device, further calculates the mapping relation between the ideal air pressure value and the real-time air pressure value, and performs parameter correction on the optical fiber pressure sensor, so that the optical fiber pressure sensor can be continuously used in different detection environments or when being matched with different probes.

The construction method of the correction function comprises the following steps:

Then the ideal gas pressure P _hi Expressed as:

P _hi ＝(n _d RT _j )/(V ₀ -ΔV)，(i＝1，2，3，......m)。

wherein n is _d Is the amount of material, T, of the gas in the pressure acquisition unit _j Is ambient temperature, V ₀ Is the initial total volume of the pressure acquisition device, Δ V is a variable of the total volume of the pressure acquisition device, and m is the total number of times the gas is injected into the closed container.

In the above formula, other parameters are fixed values except for. Because the variable of the total volume of gas of the closed container is equal to the variable of the total volume of the pressure acquisition device, the following steps are provided:

ΔV＝(P _ni /n _i RT _j )-(P ₀ /n ₀ RT _j )＝(P _i /n _d RT _j )-(P ₁ /n _d RT _j )

wherein the content of the first and second substances,

V ₀ ＝P ₁ /n _d RT

V _c -V _d ＝P ₀ /n ₀ RT

finishing to obtain:

ΔV＝(n _i RT _j )/P _ai -V _c +V _d

then the ideal air pressure P _hi Can be expressed as:

wherein n is _i The quantity of substance, P, of air at the i-th measurement of the closed container _ai Average pressure, V, measured for the ith time of the closed vessel _c Is the total volume of the closed container, V _d Is the total volume of the pressure acquisition device.

Quantity n of gaseous substances in a pressure sensor _d Expressed as:

n _d ＝P ₀ V ₀ /RT ₁

n _i ＝n ₀ +(i-1)n ₁ 。

s42: a plurality of real-time air pressure values P are collected _i A plurality of corresponding ideal air pressure values P _hi Mapping to a plane coordinate system to obtain a plurality of coordinate points A _i . And establishing a plane coordinate system by taking the real-time air pressure value as an abscissa and the ideal air pressure value as an ordinate. The real-time air pressure value and the ideal air pressure value at the same time can form a coordinate point A _i (P _i ，P _hi )。

S43: for a plurality of coordinate points A _i Performing curve fitting, and taking the fitted curve function as a correction function R _fi 。

Correction letterNumber R _fi Expressed as:

wherein, P _i Air pressure value, P, displayed in real time for pressure acquisition means _c To correct the base value, k _j Is the correction factor after the jth tempering, k _j+1 Is the correction coefficient k after the j +1 th temperature adjustment ₁ The correction coefficient is a correction coefficient at a temperature T1.

The method for obtaining the offset function comprises the following steps:

s44: a plurality of average pressures P to be collected _ni And a plurality of corresponding desired air pressure values P _hi Mapping to another plane coordinate system to obtain multiple coordinate points B _i . The average air pressure is used as an abscissa and the ideal air pressure value is used as an ordinate to establish a plane coordinate system, so that the average air pressure and the ideal air pressure value at the same moment can form a coordinate point B _i (P _ni ，P _hi )。

S45: for a plurality of coordinate points B _i Performing curve fitting, and taking the fitted curve function as a compensation function P _f 。

The offset function may be expressed as:

P _f ＝ε+K _j P _i

The interference factor epsilon is related to the elastic film of the probe and is used for representing the error value of the measurement result caused by the stress or the tension generated by the shape change of the elastic film under different air pressures.

S5: judging whether the average temperature in the closed container reaches T _max If so, based on the fitted plurality of correction functions R _fi And correcting parameters of the optical fiber pressure sensor. The corrected optical fiber pressure sensor displays the measured inner cavity air pressure in real time, and displays the actual air pressure value of the area to be measured according to a plurality of compensation functions. Otherwise, repeating the step S4 until the sealed container is obtainedThe average temperature in the container reaches T _max 。

In practical applications, if the error value caused by the temperature is within a predetermined correction error range (e.g., -0.01 to 0.01), the temperature parameter can be removed, and the average of the correction functions can be integrated to be the final correction function. The real-time air pressure value displayed by the corrected optical fiber pressure sensor is a determined value, and the optical fiber pressure sensor can be directly used for measuring other environmental pressures such as blood pressure, hydraulic pressure or air pressure.

In the calibration method for the pressure acquisition device provided by this embodiment, first, after the pressure acquisition device is vacuumized, gas is injected into the pressure acquisition device, so that the pressure acquisition device reaches the maximum volume within its measurement range, and calibration errors caused by volume changes of the pressure acquisition device are eliminated. And then, acquiring real-time air pressure values displayed by the pressure acquisition device and the average air pressure of the closed container under different temperatures and different air pressure environments, further calculating corresponding ideal air pressure according to the volume of the closed container, the total volume of the pressure acquisition device and the total volume of the pressure acquisition device, further constructing a correction function according to a mapping relation between the ideal air pressure and the actual air pressure value, and performing parameter correction on an optical fiber pressure sensor of the pressure acquisition device so as to enable the measurement precision of the optical fiber pressure sensor to meet the measurement requirement. And finally, constructing a compensation function according to the mapping relation between the measured average air pressure and the ideal air pressure so as to reduce and eliminate errors generated by the performance of the pressure acquisition device, improve the measurement precision in actual measurement and meet the precision requirement of pressure detection of the pressure acquisition device in a natural cavity or tissue gap of a human body.

In order to more intuitively know the relation between the pressure value of the area to be measured and the actually measured pressure value of the optical fiber pressure sensor, the optical fiber pressure sensor directly displays the real-time air pressure value and calculates the actual pressure value of the area to be measured according to the compensation function. Like the correction function, when the error value caused by the temperature is within the preset offset error range, the temperature parameter can be removed from the offset function, and the final offset function can be expressed as:

P _f ＝ε+P _i 。

in the actual measurement of the pressure acquisition device in the embodiment, the air pipe is detachably connected with the air storage pipe through the luer connector. When different body cavities or tissue gaps are measured, air pipes with different lengths or different materials can be selected, so that after the probe is guided into the region to be measured, the air storage pipe is positioned outside the human body, and the distance between the air storage pipe and the human body is not more than 3cm.

In the actual measurement, the pressure acquisition device displays two groups of air pressure values in real time, wherein one group is the detection cavity air pressure directly read according to the pressure sensor, and the other group is the actual air pressure of the area to be measured obtained through calculation according to the mapping relation between the ideal air pressure and the actual air pressure.

In order to verify whether the accuracy of the calibrated pressure acquisition device meets a preset standard, this embodiment further provides an experimental verification method, which includes the following specific steps:

1. the preparation process comprises the following steps:

one or more containers, such as pipes or tanks, are selected for the flow of liquid. Liquids of different densities are prepared, preferably water, alcohol, etc., and provided with solid materials for adjusting the density, such as water-soluble heavy metal salts (lead nitrate, lead acetate, zinc chloride, tin tetrachloride, calcium chloride, etc.). A micro-pump or power injector is prepared. A high-precision pressure sensor is prepared.

And respectively melting the solid materials into water according to different proportions to obtain a plurality of liquids with different densities and higher than the density of the water. Mixing alcohol and water according to different proportions to obtain a plurality of liquids with different densities and all the liquids are between the density of the alcohol and the density of the water.

2. The experimental process comprises the following steps:

the water pipe is communicated with the output port of the micro water pump. The probe of the pressure acquisition device and the probe of the high-precision pressure sensor are arranged on the same height position of the water pipe side by side, and the probe of the pressure acquisition device and the probe of the high-precision pressure sensor are both right opposite to the output port of the micro water pump. Communicating the prepared liquids at the input end of the micro water pump in sequence.

The variation range and the period of the output power of the micro water pump are set. The output power of the micro water pump is adjusted from lowest to highest in a reciprocating mode, so that the flow rate of the liquid changes along with the change. A sampling period is set. At least 10 times of sampling is needed in the period of the change of the output power of the miniature water pump.

Starting the micro water pump, and acquiring the pressure value P displayed by the high-precision pressure sensor in real time according to the sampling period _a And the pressure value P displayed by the pressure acquisition device _b (compensated pressure value). Observe each group P _a And P _b Whether the difference value of (a) is within a preset error range.

3. And (3) experimental analysis:

the natural cavity or tissue gap of human body is mostly filled with liquid with different components, and the pressure of the liquid in the cavity or tissue gap to the organs or tissues of human body is different according to the difference of the density, flow rate and total amount of the liquid. When there is disease or damage to human organ or tissue, the pressure of liquid in the cavity or gap will change. Whether the organs or tissues of the human body are healthy or not can be simply judged by measuring the pressure of the corresponding cavity or tissue gaps.

The verification experiment that this embodiment provided is used for simulating the liquid environment in human natural chamber way or the tissue gap, regards current pressure sensor who satisfies the required precision as the contrast, observes whether the real-time pressure value that the pressure acquisition device of this embodiment shows satisfies the required precision. If the pressure acquisition device of this embodiment can satisfy measurement accuracy's requirement under the environment of experimental simulation, then can directly be applied to the actual measurement of human body chamber way or tissue gap, can overcome the interference of the complicated environment in the human body.

Example 3

Referring to fig. 6 and 7, fig. 6 is a schematic cross-sectional structural view of a calibration system of the pressure acquisition device for natural body lumens of the present embodiment; fig. 7 is a schematic structural diagram of a frame of the calibration system of the pressure acquisition device for the natural orifice of the human body in fig. 6. In order to implement the calibration method of embodiment 2, this embodiment further provides a calibration system for the pressure acquisition device 10 of the natural orifice of the human body, where the calibration system includes a closed container 20, an air pump 40, an air pressure detection device 30, a temperature control device 50, a processor, and a parameter setting device.

The closed vessel 20 accommodates the pressure-collecting device 10. The closed vessel 20 is also used to provide a constant temperature environment for the calibration process. The sealed container 20 may be a metal container, a glass container, or the like, as long as it has good sealing performance, and it does not deform or leak gas during calibration. In this embodiment, the closed container 20 is a square glass box, and a valve is connected to the glass box for controlling the connection state between the inner cavity of the glass box and the air.

The air pump 40 is used to adjust the air pressure in the hermetic container 20. One end of the air pump 40 is communicated with the valve of the hermetic container 20, and the other end is communicated with the air. At the initial stage of calibration, the air pump 40 is used to inject or exhaust air into the closed container 20 so that the air pressure in the closed container 20 reaches a preset value P ₀ . The air pump 40 may also inject air into the closed vessel 20 according to the calculated amount of air per injection.

The air pressure detecting device 30 is used to monitor the average air pressure in the closed vessel 20 in real time. The air pressure detecting device 30 may use an existing pressure sensor (such as a piezoresistive pressure sensor, a piezoelectric pressure sensor, or a capacitive pressure sensor) or an air pressure sensor as long as a measurement range and a measurement accuracy required for calibration are satisfied.

The temperature control device 50 is used to adjust the average temperature of the closed vessel 20. The temperature control device 50 can be a mechanical temperature controller, an electronic temperature controller or a digital temperature controller, etc., as long as the requirement of accurate temperature control (error is not more than 0.1 ℃) within 0-50 ℃ is met.

The processor is configured to: a. and calculating the ideal air pressure according to the average air pressure acquired in real time.

Ideal air pressure P _hi Can be expressed as:

wherein n is _d For mining by pressureThe amount of gas material in the container 10, R is the universal gas constant, T _j Is ambient temperature, V ₀ Δ V is a variable of the total volume of the pressure-collecting device 10, m is the total number of times of injecting gas into the closed vessel 20, n is the initial total volume of the pressure-collecting device 10 _i The amount of substance, P, of air at the time of the i-th measurement of the closed vessel 20 _ai Average air pressure, V, measured for the i-th time of the closed vessel 20 _c Is the total volume, V, of the closed vessel 20 _d The total volume of the pressure acquisition device 10.

The amount of material n of the gas in the pressure acquisition device 10 _d Expressed as:

n _d ＝P ₀ V ₀ /RT ₁

the quantity n of the substance in the air in the closed vessel 20 at the time of the ith measurement _i Expressed as:

n _i ＝n ₀ +(i-1)n ₁ 。

b. according to ideal air pressure P _hi And a real-time measured barometric pressure value P _i And calculating the mapping relation between the ideal air pressure and the air pressure value.

And establishing a plane coordinate system by taking the real-time air pressure value as an abscissa and the ideal air pressure value as an ordinate. A plurality of real-time air pressure values P are collected _i A plurality of corresponding ideal air pressure values P _hi Mapping to a plane coordinate system to obtain a plurality of coordinate points A _i . The real-time air pressure value and the ideal air pressure value at the same time can form a coordinate point A _i (P _i ，P _hi )。

For a plurality of coordinate points A _i Performing curve fitting, and taking the fitted curve function as a correction function R _fi I.e. the mapping relationship between the ideal air pressure and the air pressure value.

c. And calculating the mapping relation between the real-time air pressure value measured by the pressure acquisition device 10 and the actual air pressure of the position to be measured according to the measured average air pressure and the corresponding ideal air pressure.

Establishing another plane coordinate system by taking the average air pressure as abscissa and the ideal air pressure value as ordinate, and collecting multiple average air pressures P _ni And a plurality of corresponding ideal gasesPressure value P _hi Mapping to another plane coordinate system to obtain multiple coordinate points B _i . The average air pressure and the ideal air pressure value at the same time may constitute a coordinate point B _i (P _ni ，P _hi )。

For a plurality of coordinate points B _i Performing curve fitting, and taking the fitted curve function as compensation function P _f I.e. the mapping relationship between the real-time air pressure value and the actual air pressure of the position to be measured.

The parameter setting device is used for setting parameters of the pressure acquisition device 10 according to the mapping relation between the ideal air pressure and the air pressure value, so that the error between the air pressure value measured by the pressure acquisition device 10 in real time and the actual air pressure value does not exceed a preset error range. In the present embodiment, the predetermined error range is [ -0.005,0.005].

By using the calibration system of the pressure acquisition device 10 provided in this embodiment, the calibration method of the pressure acquisition device 10 in embodiment 1 can be implemented to perform parameter correction on the optical fiber pressure sensor in the pressure acquisition device 10, so as to obtain the optical fiber pressure sensor meeting the measurement accuracy, so as to improve the pressure measurement accuracy of the natural orifice or tissue gap of the human body.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. A calibration method for a pressure acquisition device of a natural orifice of a human body is used for detecting an air pressure value displayed by the pressure acquisition device in real time, an error between an actual air pressure value of a region to be detected and an actual air pressure value of an inner cavity of the pressure acquisition device, and further correcting the pressure acquisition device to reduce or eliminate the error; the pressure acquisition device comprises a probe, an air pipe, an air storage pipe and an optical fiber pressure sensor; a detection cavity is arranged in the probe; an air storage chamber is arranged in the air storage pipe; the detection cavity is communicated with the air storage chamber through the air pipe; the detection cavity, the inner cavity of the air pipe and the air storage chamber jointly form the detection cavity; the optical fiber pressure sensor is used for detecting the average air pressure of the detection cavity; the calibration method is characterized by comprising the following steps:

s1: vacuumizing the pressure acquisition device until the air pressure of a detection cavity of the pressure acquisition device is lower than a preset threshold value; at a pressure value of P ₀ Under the constant pressure environment, air is injected into the detection cavity until the real-time air pressure value displayed by the optical fiber pressure sensor keeps unchanged, and the real-time air pressure value P displayed by the optical fiber pressure sensor at the moment is recorded ₁ (ii) a Continuously injecting air into the detection cavity until the real-time air pressure value displayed by the optical fiber pressure sensor just changes;

s2: setting the calibration temperature range to [ T ] ₁ ，T _max ](ii) a Setting the calibrated pressure range to [ P ] ₀ ，P _max ](ii) a Placing the pressure acquisition device at an average temperature T ₁ The constant temperature closed container; injecting or exhausting gas into the closed container until the average gas pressure in the closed container is P ₀ ；

S3: n is injected into the closed container at each time ₁ Adjusting the average air pressure in the closed container by mol air, and measuring the average air pressure P in the closed container in real time _ni (ii) a Reading the real-time air pressure value P displayed by the optical fiber pressure sensor _i ；

S4: judging the average air pressure P _ni Whether or not higher than P _max If so, the average temperature in the closed container is increased by delta T, and the closed container is evacuated to make the average temperatureAir pressure P _ni Is restored to P ₀ (ii) a According to a plurality of acquired average air pressures P simultaneously _ni And corresponding real-time barometric pressure value P _i Adopting a curve fitting method to construct a correction function and a compensation function under the current temperature condition; said correction function characterizing the ideal air pressure P _hi And real-time air pressure value P _i The mapping relationship between the two; the penalty function characterizes the ideal gas pressure P _hi And average gas pressure P _ni The mapping relationship between the two; otherwise, repeating the step S3 until the average air pressure P _ni Higher than P _max (ii) a The construction method of the correction function comprises the following steps:

s41: according to each said average air pressure P _ni And the total volume V of the pressure acquisition device _d Calculating the ideal air pressure P of the pressure acquisition device _hi ；

S42: a plurality of real-time air pressure values P are collected _i A plurality of corresponding ideal air pressure values P _hi Mapping to a plane coordinate system to obtain a plurality of coordinate points A _i ；

S43: for a plurality of coordinate points A _i Performing curve fitting to obtain fitted curve function R _fi As a correction function;

the method for obtaining the offset function comprises the following steps:

s44: a plurality of average pressures P to be collected _ni And a plurality of corresponding desired air pressure values P _hi Mapping to another plane coordinate system to obtain multiple coordinate points B _i ；

S45: for a plurality of coordinate points B _i Performing curve fitting to obtain a fitted curve function P _f As a function of offset;

s5: judging whether the average temperature in the closed container reaches T _max If so, based on the fitted plurality of correction functions R _fi Correcting parameters of the optical fiber pressure sensor; the corrected optical fiber pressure sensor displays the measured inner cavity air pressure in real time, and displays the actual air pressure value of the area to be measured according to a plurality of compensation functions; otherwise, repeating the step S4 until the average temperature in the closed container reaches T _max 。

2. The calibration method of the pressure acquisition device for the natural orifice of the human body according to claim 1, wherein in S2, when the average air pressure of the closed container just reaches P ₀ Judging whether the real-time air pressure value displayed by the optical fiber pressure sensor is also P ₀ If yes, continuing to calibrate; otherwise, synchronously regulating the average air pressure in the closed container and the air pressure in the detection cavity until the average air pressure P _ni And said air pressure value P _i Are all P ₀ 。

3. The calibration method of the pressure acquisition apparatus for the natural orifice of the human body according to claim 1, wherein in S3, the amount of air injected at each time is calculated by:

s31: according to the current temperature of the closed container and the initial air pressure P of the closed container ₀ Volume V of the sealed container _c And initial total volume V of pressure acquisition device _d Calculating the quantity n of the initial substance of the air in the closed container ₀ (ii) a Then n is ₀ Expressed as:

n ₀ ＝P ₀ (V _c -V _d )/RT ₁

wherein n is ₀ Amount of starting material, V, of gas in a closed container _c Is the volume of the closed container, V _d Is the initial total volume of the pressure acquisition device, T ₁ Is the initial temperature;

n ₁ ＝ΔPn ₀ /P ₀

4. The calibration method of the pressure acquisition device for the natural orifice of the human body according to claim 1, wherein in S41, the ideal air pressure P is _hi Expressed as:

wherein n is ₀ Is the quantity of material, T, of the gas in the pressure acquisition unit _j Is ambient temperature, V ₀ Is the initial total volume of the pressure acquisition device, Δ V is the variable of the total volume of the pressure acquisition device, m is the total number of times of gas injection into the closed container, n _i The quantity of substance, P, of air at the i-th measurement of the closed container _ai Average pressure, V, measured for the ith time of the closed vessel _c Is the total volume of the closed container, V _d Is the total volume of the pressure acquisition device.

5. The method for calibrating a pressure transducer for a natural orifice of the human body according to claim 4, wherein the amount of substance n of the gas in the pressure transducer is S41 _d Expressed as:

n _d ＝P ₀ V ₀ /RT ₁

n _i ＝n ₀ +(i-1)n ₁ 。

6. the calibration method for the pressure acquisition device of the natural orifice of the human body as claimed in claim 5, wherein in S43, the correction function R _fi Expressed as:

wherein, P _i Air pressure value, P, displayed in real time for pressure acquisition means _c To correct the base value, k _j Is the correction factor after the jth tempering, k _j+1 Is the correction coefficient after the j +1 th temperature adjustment, k ₁ The correction coefficient is a correction coefficient at a temperature T1.

7. The calibration method of the pressure acquisition device for the natural orifice of the human body according to claim 6, wherein in S45, the offset function is expressed as:

P _f ＝ε+K _j P _i

8. A calibration system for a pressure acquisition device of a natural orifice of a human body, which adopts the calibration method for the pressure acquisition device of the natural orifice of the human body as claimed in any one of claims 1 to 7 to calibrate the parameters of the pressure acquisition device; it is characterized in that it comprises:

the closed container is used for accommodating the pressure acquisition device and providing a constant temperature environment required by a calibration process;

a valve communicated with the closed container and used for controlling the communication state of the closed container and air;

the air pump is used for adjusting the air pressure in the closed container;

an air pressure detecting device for detecting an average air pressure in the closed container in real time; and

and the temperature control device is used for adjusting the average temperature of the closed container.

9. The calibration system for a pressure acquisition device for a natural orifice of the human body according to claim 8, further comprising a processor configured to: a. acquiring ideal air pressure in a conversion table according to the average air pressure acquired in real time, wherein the conversion table represents the mapping relation between the average air pressure and the ideal air pressure; b. calculating a mapping relation between the ideal air pressure and the real-time air pressure value according to the calculated ideal air pressures and the real-time air pressure values measured by the pressure acquisition devices in real time; c. and calculating the mapping relation between the real-time air pressure value measured by the pressure acquisition device and the actual air pressure of the position to be measured according to the measured average air pressure and the corresponding ideal air pressure.

10. The calibration system for the pressure acquisition device of the natural orifice of the human body according to claim 9, characterized in that the calibration system further comprises a parameter setting device; the parameter setting device is used for setting the parameters of the pressure acquisition device according to the mapping relation between the ideal air pressure and the real-time air pressure value, so that the error between the real-time air pressure value measured by the pressure acquisition device and the actual air pressure value of the position to be measured does not exceed a preset error range.