CN210863618U

CN210863618U - Expiration detection device

Info

Publication number: CN210863618U
Application number: CN201921371901.6U
Authority: CN
Inventors: 刘博引; 陈裕殷; 徐洪涛
Original assignee: Beijing Zhiji Future Medical Technology Co ltd
Current assignee: Beijing Zhiji Future Medical Technology Co ltd
Priority date: 2019-08-22
Filing date: 2019-08-22
Publication date: 2020-06-26
Anticipated expiration: 2029-08-22

Abstract

The embodiment of the utility model discloses expiration detection device, wherein, expiration detection device adopts and is based on TiO₂The gas sensor of nano sensitive material, expiration detection device includes air inlet unit, the unit of giving vent to anger, gas sensor, first gas filter unit, second gas filter unit, third gas filter unit and gaseous detection room, air inlet unit, the unit of giving vent to anger, first gas filter unit, second gas filter unit, third gas filter unit all communicate with gaseous detection room, and gas sensor installs in the inside of gaseous detection room. The embodiment of the utility model provides an expirationThe detection device can realize the quantitative analysis of the concentration of common gases in human body expiration including acetone and ammonia gas, and obtain the relevant conditions of dietary metabolism from the concentration, and is used for evaluating auxiliary reference information of disease risks such as diabetes, chronic renal failure and the like.

Description

Expiration detection device

Technical Field

The embodiment of the utility model provides a technical field, concretely relates to expiration detection device of gas sensor is related to.

Background

With the development of science and technology and the improvement of the cognition degree of people, the detection idea taking non-wound as the core has entered the visual field of people. The clinical practice guidelines issued by the American Thoracic Society (ATS) in 2011 suggest that the detection of nitric oxide levels in exhaled breath (FeNO) supports the diagnosis of respiratory diseases such as asthma. The roman consensus in 2009 and the north american consensus in 2017 also suggested that intestinal health could be judged by measuring the levels of hydrogen and methane in the expired air.

The detection of acetone gas in breath has been carried out as early as 50 years ago. At that time, the acetone content in the breath was used to indirectly reflect the caloric intake of food, the composition of dietary nutrients, and the efficiency of exercise. In practice, the acetone content in breath is used as a reference index for assessing the weight loss effect, and the index is mainly used for assisting in distinguishing the artifact of weight loss caused by water loss, rather than substantial fat loss, of a human body.

In recent years, a number of scientific literature has made correlations between the concentration of acetone in human breath and whether an individual has diabetes. The data show that the acetone concentration is between 300-900ppb in the expired breath from non-diabetic patients, while the acetone concentration reaches over 1800ppb in the expired breath from diabetic patients. The main reason for the elevated acetone in the expired breath of diabetic patients is that they are unable to metabolize the carbohydrates of the ingested diet efficiently, and without pharmaceutical and other forms of intervention, the metabolic energy of the patients is mostly derived from the process of fat breakdown. This process is accompanied by the formation of ketone bodies, including acetoacetate, hydroxybutyrate, and acetone. Of the three, acetone molecules are small enough to enter the lungs through the blood and exit through the breath, providing conditions for detection. Thus, a diabetic patient, after eating, eventually experiences an increase in the concentration of acetone in his breath due to an abnormal increase in the metabolism of ketone bodies in his body.

On the other hand, it has been experimentally reported that the concentration of ammonia gas in human breath is related to whether the examinee has chronic renal failure. The concentration of ammonia in the expired breath from patients with chronic renal failure is 0.82-14.7ppm, while the concentration of ammonia in expired breath from people with non-chronic renal failure is 0.25-2.9 ppm. The real-time monitoring of ammonia gas in human expiration can also reflect the effect of chronic renal failure patients before and after receiving hemodialysis treatment. Clinical data show that during hemodialysis, acetone levels in the breath of patients with chronic renal failure decreased significantly and were positively correlated with the trend of decreasing urea levels in the blood.

In addition, the main metabolic source of ammonia in the human body is the decomposition of amino acids, and the ammonia generated in the process firstly enters the blood in the form of urea and finally is discharged in the form of urine (few parts are sweat) through the kidney. When the kidney is in trouble and fails to filter the urea in the blood effectively, the urea will decompose in the blood and be converted back into ammonia. Ammonia in the blood passes through the lungs and is expelled from the exhaled breath.

In the breath of healthy people, the endogenous production of methanol and ethanol mainly comes from the digestion of food (such as fruits) by the intestinal tract. The concentration of these two gases is directly related to the type and amount of food ingested. The detection of these two breath components may reflect to some extent the health of the gut.

In summary, the concentration of the specific gas in the exhaled breath of the human body may become an important detection index in the future noninvasive disease diagnosis field. However, the main challenge of gas detection is (1) whether the detection means can meet the standards of high selectivity, high sensitivity and low detection lower limit for the target detection gas; (2) detecting whether the execution and operation of the process can be accepted by the object group to which the detection is directed; (3) whether the cost of the detection equipment can be controlled within the range approved by the detection object groups. This generally requires that the sensitivity and lower limit of detection of the respective sensor/detection device itself for the gas to be detected reach 10²ppb level.

Currently, the gas concentration quantitative analysis instruments that can satisfy this prerequisite are mostly based on mass spectrometry or optical detection, which includes the identification and quantitative analysis of specific gases using ultraviolet light or infrared light of specific wavelengths. However, both of these detection means, both in terms of manufacturing cost and operational difficulty, are far beyond the range of economic and professional capabilities that can be accepted by the average individual user. In contrast, the nano semiconductor gas sensor has the advantages of low production cost and simple manufacturing process. Moreover, the use of such materials does not require the reliance on very complex circuit structures and manual sample handling procedures. Nevertheless, the nano semiconductor gas sensor, when it is an individual working alone, cannot achieve a very desirable effect in terms of gas selectivity. Because the nano semiconductor gas sensor depends on the judgment of the oxidation-reduction property of target detection gas, the detection signals of gases with very close reduction property, such as methanol, ethanol and acetone, are difficult to distinguish by the nano semiconductor gas sensor alone.

SUMMERY OF THE UTILITY MODEL

Therefore, the embodiment of the utility model provides an expiration detection device to solve the detection means among the prior art problem with high costs, that the operation is difficult and gas selectivity is not good.

In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:

the embodiment of the utility model provides a based on TiO₂The gas sensor of nano sensitive material comprises a ceramic tube, a gold electrode and a nickel-chromium alloy electric heating wire, wherein the gold electrode is fixed at two ends of the ceramic tube, the outer surfaces of the ceramic tube and the gold electrode are covered with nano sensitive material, the nickel-chromium alloy electric heating wire is arranged in the ceramic tube, and the nano sensitive material is TiO₂The nano sensitive material is prepared by the following steps:

step S1, mixing titanium tert-butoxide with ethylene glycol in a ratio of 1: 30-1: 50, placing the mixture in a water bath at the temperature of 40-80 ℃ for heating and stirring to obtain a solution A;

step S2, placing the solution A to room temperature, and then adding an acetone solution with the same volume to obtain a suspension B;

step S3, stirring the suspension B at room temperature to obtain a fixed product C;

step S4, alternately carrying out centrifugal washing on the fixed product C by using deionized water and ethanol to obtain a product D, and placing the product D in a drying oven at the temperature of 40-80 ℃ for overnight drying to obtain a product E;

step S5, adding the E product into deionized water according to the proportion of 0.7-1% (w/v), and then performing hydrothermal reaction at 100-;

step S6, centrifuging the F product to obtain solid sediment, cleaning the solid sediment with deionized water, and drying the solid sediment at 40-80 ℃ to obtain TiO₂And (3) nano sensitive material.

Preferably, the ceramic tube of the gas sensor has a length of 3-5 mm, an outer diameter of 1-1.5 mm and an inner diameter of 0.6-0.8 mm; the width of each gold electrode is 0.3-0.6 mm.

This example provides a TiO-based material₂Preparation method of gas sensor made of nano sensitive material based on TiO₂The preparation method of the gas sensor of the nano sensitive material comprises the following steps:

step S1, slowly adding deionized water to the TiO₂In the nano sensitive material, slurry with certain viscosity is formed;

step S2, coating the slurry on the outer surface of the ceramic tube by a brush and completely covering the gold electrode;

step S3, placing a nickel-chromium alloy heating wire in the ceramic tube;

step S4, leading out a Peltier wire from the gold electrodes at the two ends of the ceramic tube, wherein the Peltier wire is used for welding the ceramic tube on the indirectly heated hexagonal tube seat;

step S5, aging the sensor obtained in step S4 in an air environment of 100-500 ℃ for 48-72 hours to obtain the sensor based on TiO₂A gas sensor made of nano sensitive material.

In addition, the present embodiment provides an expired air detecting apparatus, which employs a TiO-based method₂The breath detection device comprises an air inlet unit, an air outlet unit, a gas sensor, a first gas filtering unit, a second gas filtering unit, a third gas filtering unit and a gas detection chamber, wherein the air inlet unit, the air outlet unit, the first gas filtering unit, the second gas filtering unit, the third gas filtering unit and the gas detection chamber are arranged in parallelThe gas filter units are communicated with the gas detection chamber, and the gas sensor is arranged in the gas detection chamber;

the air inlet unit comprises an air faucet, an air inlet pipe, an electromagnetic valve a and an air blowing valve, one end of the air inlet pipe is communicated with the air faucet, the other end of the air inlet pipe is communicated with the air detection chamber, the electromagnetic valve a and the air blowing valve are mounted on the air inlet pipe, and the air blowing valve is located between the air faucet and the electromagnetic valve a;

the first gas filtering unit comprises a first gas filter, a first input pipe, a first output pipe, an electromagnetic valve b and a first air pump, silica gel is placed in the first gas filter, one end of the first input pipe is connected with the gas detection chamber, the other end of the first input pipe is connected with the first gas filter, and the electromagnetic valve b is arranged on the first input pipe; one end of the first output pipe is connected with the gas detection chamber, the other end of the first output pipe is connected with the first gas filter, and a first air pump is arranged on the first output pipe;

the second gas filtering unit comprises a second gas filter, a second input pipe, a second output pipe, an electromagnetic valve d and a second air pump, wherein the second gas filter is internally provided with the second air pump

One end of the second input pipe is connected with the gas detection chamber, the other end of the second input pipe is connected with the second gas filter, and the second input pipe is provided with an electromagnetic valve d; one end of the second output pipe is connected with the gas detection chamber, the other end of the second output pipe is connected with a second gas filter, and a second air pump is arranged on the second output pipe;

the third gas filtering unit comprises a third gas filter, a third input pipe, a third output pipe, an electromagnetic valve e and a third air pump, wherein the third gas filter is internally provided with a third gas filter

One end of the third input pipe is connected with the gas detection chamber, the other end of the third input pipe is connected with a third gas filter, and an electromagnetic valve e is arranged on the third input pipe;one end of the third output pipe is connected with the gas detection chamber, the other end of the third output pipe is connected with a third gas filter, and a third air pump is arranged on the third output pipe;

the air outlet unit comprises an air outlet pipe, a fourth air pump and an electromagnetic valve c, the air outlet pipe is communicated with the gas detection chamber, the fourth air pump and the electromagnetic valve c are arranged on the air outlet pipe, and the electromagnetic valve c is located between the gas detection chamber and the fourth air pump.

Preferably, the valve of blowing includes air intake passage, the air flue of giving vent to anger, air pressure control air flue, screw cap and bearing ball, just air intake passage, air flue and the mutual intercommunication of air pressure control air flue of giving vent to anger, air flue and air cock intercommunication of giving vent to anger, place bearing ball in the air pressure control air flue, bearing ball is used for instructing pressure and the velocity of flow that the detection person blown, just the free end lid of air pressure control air flue has the screw cap, the screw cap is used for controlling opening and closing of air pressure control air flue.

Preferably, the interface of the air pressure control air passage and the air inlet air passage or the air outlet air passage is connected by a porous isolation layer.

Preferably, the weight of the bearing ball is not less than 10 g, and the outer surface of the bearing ball is coated with an antibacterial coating.

Preferably, the working temperature of the gas sensor is 250 ℃ to 350 ℃, and the reaction time is 10 seconds.

Preferably, the gas detection chamber is in the shape of a pentagonal prism, and five side surfaces of the gas detection chamber are respectively connected with the gas inlet unit, the gas outlet unit, the first gas filtering unit, the second gas filtering unit and the third gas filtering unit.

Preferably, the outer diameter of the air blowing valve is less than 3 cm.

The embodiment of the utility model provides a have following advantage:

firstly, the embodiment of the utility model provides a based on TiO₂The gas sensor of nano sensitive material is a indirectly heated structure, and is formed from ceramic tube substrate and anatase type TiO coated on its surface₂The nano material is provided with gold electrodes at two ends.The heating wire of nickel-chromium alloy is placed in the ceramic tube for heating the sensor to working temperature. The gas sensor has high recognition sensitivity to methanol, ethanol, acetone and ammonia gas. In different gas environments, the existence of the above gases can cause the sensor to generate different degrees of resistance value changes.

Before use, the resistance value of the gas sensor is in linear correlation with methanol, ethanol, acetone and ammonia gas in a certain concentration range. When the molecular sieve, the gas path structure and the detection logic of a specific type are combined, the filtering, separation, association and identification of specific gas can be realized, the concentration quantitative analysis of common gas in human body expiration including acetone and ammonia gas is completed, and the relevant conditions of dietary metabolism and auxiliary reference information for evaluating the risks of diseases such as diabetes, chronic renal failure and the like are obtained.

When the gas sensor is used for detection, the operation is very simple, the detection cost is greatly reduced, and the gas to be detected can be automatically corresponding to the detection output value.

Secondly, the embodiment of the utility model provides a based on TiO₂The preparation method of the gas sensor of the nano sensitive material has simple operation and can quickly prepare the gas sensor based on the TiO₂A gas sensor made of nano sensitive material.

Thirdly, the embodiment of the utility model provides an expiration detection device at first needs to carry out zero calibration to air circumstance, later to the gas that the person of examining was blown the collection the same time and carry out at least cubic to be detected, and the detected object is (1) untreated gas respectively, (2) through the process

After the molecular sieve treatment (ammonia gas filtration), the gas (3) is treated by

After molecular sieve treatment (methanol and ethanol were filtered off on the basis of the previous step). The breath detection device controls the gas detection chamber and the gas filtering containers by different solenoid valvesAnd connecting and isolating, and circulating the gas between the detection gas chamber and the gas filtering container by using a suction pump, thereby enhancing the adsorption and filtering effects of the molecular sieve in the gas filtering container on the specific gas. The air paths of the single electromagnetic valve, the air filtering container and the air pump are relatively independent and are communicated with other units only through the detection air chamber. Finally, the concentration of acetone and ammonia gas in the breath of the examiner can be accurately calculated by integrating the detection values obtained by three times of measurement and the air zero value, and the detection method is low in cost, simple to operate and good in gas selectivity.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structure, ratio, size and the like shown in the present specification are only used for matching with the content disclosed in the specification, so as to be known and read by people familiar with the technology, and are not used for limiting the limit conditions which can be implemented by the present invention, so that the present invention has no technical essential significance, and any structure modification, ratio relationship change or size adjustment should still fall within the scope covered by the technical content disclosed by the present invention without affecting the efficacy and the achievable purpose of the present invention.

FIG. 1 shows TiO provided in the embodiment of the present invention₂SEM image of nano gas-sensitive material;

FIG. 2 shows TiO provided in the embodiment of the present invention₂XRD pattern of nano gas-sensitive material;

FIG. 3 is a view of TiO provided by an embodiment of the present invention₂A resistance value signal diagram generated by the nano gas sensor for different gases;

FIG. 4 is a view showing the embodiment of the present invention₂Sensitivity of nano gas-sensitive sensor to acetone with different concentrationsA degree signal graph;

fig. 5 is a schematic structural view of an exhalation detection device according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of an air blowing valve of the breath detection apparatus according to the embodiment of the present invention;

in the figure: 1. an air intake unit; 11. an air tap; 12. an air inlet pipe; 13. an electromagnetic valve a; 14. a blowing valve; 141. an intake air passage; 142. an air outlet passage; 143. an air pressure control air passage; 144. a screw cap; 2. an air outlet unit; 21. an air outlet pipe; 22. a fourth air pump; 23. a solenoid valve c; 3. a first gas filtration unit; 31. a first gas filter; 32. a first input pipe; 33. a first output pipe; 34. a solenoid valve b; 35. a first air pump; 4. a second gas filtration unit; 41. a second gas filter; 42. a second input pipe; 43. a second output pipe; 44. a solenoid valve d; 45. a second air pump; 5. a third gas filtration unit; 51. a third gas filter; 52. a third input pipe; 53. a third output pipe; 54. an electromagnetic valve e; 55. a third air pump; 6. a gas detection chamber.

Detailed Description

The present invention is described in terms of specific embodiments, and other advantages and benefits of the present invention will become apparent to those skilled in the art from the following disclosure. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Example 1

Referring to fig. 1 to 4, the present embodiment provides a TiO-based optical fiber₂The gas sensor of the nanometer sensitive material comprises a ceramic tube, a gold electrode and a nickel-chromium alloy electric heating wire, wherein the gold electrode is fixed at two ends of the ceramic tube, the nanometer sensitive material covers the outer surfaces of the ceramic tube and the gold electrode, and the nickel-chromium alloy electric heating wire is arranged in the ceramic tube. Wherein the nano sensitive material is TiO₂The nano sensitive material is prepared by the following steps：

Step S1, mixing 2ml of titanium tert-butoxide with 60ml of ethylene glycol, and then placing the mixture into a water bath at 40-80 ℃ to be heated and stirred to obtain solution A.

Preferably, the temperature of the water bath is 60 ℃, and the stirring time is 3 hours, so that the titanium tert-butoxide and the ethylene glycol are mixed more uniformly, and the water bath effect is better.

In step S2, the solution a is left at room temperature and then added to a mixed solution of 50ml of acetone and 10ml of deionized water to obtain a suspension B.

And step S3, stirring the suspension B at room temperature to obtain a C-immobilized product.

Preferably, the stirring time is 2 hours.

Step S4, the fixed product C is washed by centrifugation alternately with deionized water and ethanol (5000rpm/5 min) to obtain the product D, namely titanium glycolate, and the product D is dried in a drying oven at 40-80 ℃ overnight to obtain the product E.

Preferably, the temperature of the drying oven is 60 ℃.

Step S5, the E product is put into deionized water (ratio: 0.25g/35ml), and then the mixture is put into 100-200 ℃ for hydrothermal reaction to obtain the F product.

Preferably, the reaction time is 6 hours and the reaction temperature is 180 ℃.

Step S6, centrifuging the F product to obtain solid sediment (5000rpm/5 min), washing the solid sediment with deionized water, and drying the solid sediment at 40-80 ℃ to obtain TiO₂And (3) nano sensitive material.

Preferably, the temperature of drying is 65 ℃ and the duration of drying is 3 hours.

Further preferably, the ceramic tube of the gas sensor has a length of 3-5 mm, an outer diameter of 1-1.5 mm and an inner diameter of 0.6-0.8 mm; the width of a single gold electrode is 0.3-0.6 mm, so that the sensitivity of the gas sensor is better ensured.

Specifically, the ceramic tube of the gas sensor has a length of 4mm, an outer diameter of 1.2mm and an inner diameter of 0.8 mm; the width of the single gold electrode is 0.5mm, which further ensures the sensitivity of the gas sensor.

As shown in FIG. 1, TiO₂The nano gas-sensitive material presents an agglomerated porous medium under scanning of SEM, and the form is favorable for rapid circulation of gas.

As shown in FIG. 2, TiO₂In XRD analysis, the nano gas-sensitive material presents a tetragonal anatase phase structure, which is consistent with JCPDS No. 21-1272.

As shown in FIG. 3, the TiO₂The nano gas-sensitive sensor has high identification sensitivity to 200ppm of methanol, ethanol, acetone and ammonia gas respectively, and can effectively detect the acetone and the ammonia gas.

As shown in FIG. 4, the TiO₂The lower limit of the nano gas sensor on the detection of acetone can reach 500ppb, and the requirement on the lower limit of the detection of acetone in the breath detection is met.

The TiO-based material provided in this example₂The gas sensor of nano sensitive material is a indirectly heated structure, and is formed from ceramic tube substrate and anatase type TiO coated on its surface₂The nano material is provided with gold electrodes at two ends. The heating wire of nickel-chromium alloy is placed in the ceramic tube for heating the sensor to working temperature. The gas sensor has high recognition sensitivity to methanol, ethanol, acetone and ammonia gas. In different gas environments, the existence of the above gases can cause the sensor to generate different degrees of resistance value changes.

Example 2

Referring to fig. 1 to 4, the present embodiment provides a TiO-based optical fiber₂Method for preparing gas sensor of nano sensitive material based on TiO₂Gas-sensitive transmission of nano sensitive materialThe preparation method of the sensor comprises the following steps:

step S1, slowly adding deionized water to the TiO₂And (3) in the nano sensitive material, until slurry with certain viscosity is formed.

Step S2, the slurry is coated on the outer surface of the ceramic tube with a brush and the gold electrode is completely covered.

And step S3, placing a nickel-chromium alloy heating wire in the ceramic tube.

And step S4, leading out Peltier wire from the gold electrodes at the two ends of the ceramic tube, wherein the Peltier wire is used for welding the ceramic tube on the indirectly heated hexagonal tube seat.

Preferably, the temperature during aging is 200 ℃.

In the embodiment, when the gas sensor is used for detection, the operation is very simple, the detection cost is greatly reduced, and the gas to be detected can be accurately selected.

Example 3

Referring to fig. 5 to 6, the present embodiment provides an exhalation detection device using a TiO-based exhalation detection device₂The gas sensor of nano sensitive material, expiration detection device include admit air unit 1, give vent to anger unit 2, gas sensor (not shown in the figure), first gas filter unit 3, second gas filter unit 4, third gas filter unit 5 and gaseous detection room 6, admit air unit 1, give vent to anger unit 2, first gas filter unit 3, second gas filter unit 4, third gas filter unit 5 all with gaseous detection room 6 intercommunication, and gas sensor installs in the inside of gaseous detection room 6.

The air inlet unit 1 comprises an air tap 11, an air inlet pipe 12, an electromagnetic valve a13 and an air blowing valve 14, one end of the air inlet pipe 12 is communicated with the air tap 11, the other end of the air inlet pipe 12 is communicated with the gas detection chamber 6, the electromagnetic valve a13 and the air blowing valve 14 are installed on the air inlet pipe 12, and the air blowing valve 14 is located between the air tap 11 and the electromagnetic valve a 13.

The first gas filtering unit 3 comprises a first gas filter 31, a first input pipe 32, a first output pipe 33, an electromagnetic valve b34 and a first air pump 35, silica gel is placed in the first gas filter 31, one end of the first input pipe 32 is connected with the gas detection chamber 6, the other end of the first input pipe 32 is connected with the first gas filter 31, and the electromagnetic valve b34 is arranged on the first input pipe 32; one end of the first output pipe 33 is connected to the gas detection chamber 6, the other end is connected to the first gas filter 31, and a first suction pump 35 is provided on the first output pipe 33.

The second gas filtering unit 4 includes a second gas filter 41, a second input pipe 42, a second output pipe 43, a solenoid valve d44, and a second suction pump 45, and the second gas filter 41 has a second gas filter 41 therein

A molecular sieve, one end of the second input pipe 42 is connected with the gas detection chamber 6, the other end is connected with the second gas filter 41, and the second input pipe 42 is provided with an electromagnetic valve d 44; one end of the second output pipe 43 is connected to the gas detection chamber 6, the other end is connected to the second gas filter 41, and a second suction pump 45 is provided on the second output pipe 43.

The third gas filtering unit 5 includes a third gas filter 51, a third input pipe 52, a third output pipe 53, a solenoid valve e54, and a third suction pump 55, and the third gas filter 51 has a third gas filter

One end of a third input pipe 52 of the molecular sieve is connected with the gas detection chamber 6, the other end of the third input pipe is connected with a third gas filter 51, and an electromagnetic valve e54 is arranged on the third input pipe 52; one end of the third output pipe 53 is connected to the gas detection chamber 6, the other end is connected to the third gas filter 51, and a third suction pump 55 is provided on the third output pipe 53.

The gas outlet unit 2 comprises a gas outlet pipe 21, a fourth air pump 22 and an electromagnetic valve c23, the gas outlet pipe 21 is communicated with the gas detection chamber 6, the fourth air pump 22 and the electromagnetic valve c23 are arranged on the gas outlet pipe 21, and the electromagnetic valve c23 is located between the gas detection chamber 6 and the fourth air pump 22.

Preferably, the air blowing valve 14 includes an air inlet passage 141, an air outlet passage 142, an air pressure control passage 143, a screw cap 144 and a bearing ball (not shown in the figure), the air inlet passage 141, the air outlet passage 142 and the air pressure control passage 143 are communicated with each other, the air inlet passage 141 is communicated with the air tap 11, the air outlet passage 142 is communicated with the gas detection chamber 6, the bearing ball is placed in the air pressure control passage 143, the bearing ball is used for indicating the pressure and the flow rate of the air blown by the detector, the screw cap 144 is covered at the free end of the air pressure control passage, the screw cap 144 is used for controlling the opening and closing of the air pressure control passage, and the air blowing valve 14 can better control the pressure and the flow rate of the air blown.

Further preferably, the interface of the air pressure control air passage 143 and the air inlet passage 141 or the air outlet passage 142 is connected by a porous isolation layer, which facilitates control of the pressure and flow rate of the air blown by the examiner.

In this embodiment, the weight of the bearing ball is not less than 10 g, and the outer surface of the bearing ball is coated with an antibacterial coating, which facilitates the control of the bearing ball in a suspended state, so as to limit the expiratory flow.

In the embodiment, the working temperature of the gas sensor is 250-350 ℃, and the reaction time is 10 seconds, which is beneficial to the full reaction of the gas sensor.

Preferably, the gas detection chamber 6 is in the shape of a pentagonal prism, and five sides of the gas detection chamber 6 are respectively connected with the gas inlet unit 1, the gas outlet unit 2, the first gas filtering unit 3, the second gas filtering unit 4 and the third gas filtering unit 5, which greatly simplifies the structure of the gas detection chamber 6 and facilitates the connection of the gas detection chamber 6 with other units.

It is further preferred that the outer diameter of the air blow valve 14 is less than 3cm, which facilitates air blow by the examiner.

In the embodiment, the single detection link of the breath detection device comprises two parts, namely air zero calibration and breath collection and detection. The operation of the breath detection device will be described below.

After the expiration detection device is started, air zero calibration is firstly carried out:

first, the remaining gas in each chamber is purged.

Next, in addition to solenoid valve b34, solenoid valve d44, and solenoid valve e54, solenoid valve a13, solenoid valve c23, first suction pump 35, second suction pump 45, third suction pump 55, and fourth suction pump 22 are all opened for at least 10 seconds, which ensures that first gas filter 31, second gas filter 41, and third gas filter 51 are all in a state close to vacuum.

And secondly, closing the first air pump 35, the second air pump 45 and the third air pump 55, and closing the fourth air pump 22 after 5-10 seconds to enable the gas in the gas inlet unit 1, the gas outlet unit 2 and the gas detection chamber 6 to be in a natural circulation state, so as to ensure that the gas in the gas detection chamber 6 is in a relative balance state with the outside.

Again, solenoid valve a13 and solenoid valve c23 are closed, creating a closed environment for gas detection chamber 6. The gas in the gas detection chamber 6 at this time corresponds to the air composition at that time.

Then, entering a gas detection stage:

step 1, the electromagnetic valve b34 and the first air pump 35 are opened, so that gas circulates between the gas detection chamber 6 and the first gas filter 31 filled with silica gel, in the process, the gas sensor continuously detects the gas dried by the silica gel in the circulation, and a relatively stable signal value R1 is obtained after 10 seconds.

Step 2, closing the electromagnetic valve b34, making all the gas flow into the gas detection chamber 6 under the action of the first air pump 35, opening the electromagnetic valve d44 and the second air pump 45, making the gas in the gas detection chamber 6 and the container with the gas

The second gas filter 41 of the molecular sieve is circulated, and the sensor detects the gas in the circulation and obtains a relatively stable signal value R2 after 10 seconds. The first suction pump 35 is thereafter operated in a low current state, protecting the relevant electric components from the influence of an excessive negative pressure while preventing the gas in the gas detection chamber 6 from flowing into the first gas filter unit 3.

Step 3, closing the electromagnetic valve d44, making all the gas flow into the gas detection chamber 6 under the action of the second air pump 45, opening the electromagnetic valve e54 and the third air pump 55, making the gas in the gas detection chamber 6 and the container with the gas

The third gas filter 51 of the molecular sieve is circulated, and in the process, the gas sensor detects the gas in the circulation, and a relatively stable signal value R3 is obtained after 10 seconds. The second suction pump 45 is thereafter operated in a low current state, protecting the relevant electric components from the influence of an excessive negative pressure while preventing the gas in the gas detection chamber 6 from flowing into the second gas filtering unit 4.

And 4, closing the electromagnetic valve e54, allowing all gas to flow into the gas detection chamber 6 under the action of the third air pump 55, opening the electromagnetic valve c23, and keeping the fourth air pump 22 closed, so that the gas in the gas detection chamber 6 is in a state of relative balance with the outside, wherein the gas sensor does not need to perform detection in the process. The third suction pump 55 is thereafter operated in a low current state to protect the relevant electric components from an excessive negative pressure while preventing the gas in the detection gas chamber from flowing into the third gas filtering unit 5.

To this end, the air zero calibration is completed, and then the expiration detection phase is entered:

first, an expired air collection is performed:

secondly, the electromagnetic valve a13 and the electromagnetic valve c23 are opened, a tester blows air to the mouthpiece, and the load-bearing ball in the air blowing valve 14 is ensured to be just in a suspension state as far as possible, so that the flow of the expired air is limited, and the continuous blowing is ensured to reach 5-10 seconds. In this process, the gas remaining in the gas detection chamber 6 is discharged to the air through the gas outlet unit 2 and is replaced by the exhaled breath of the subject. When the continuous blowing of the insufflator reaches 8 seconds, the electromagnetic valve c23 is closed, and when the continuous blowing reaches 10 seconds, the electromagnetic valve a13 is closed, and the collection of the expired air of the examiner is completed. The determination of the blowing time can be realized by sensing through a gas pressure sensor, or a digital display screen and a timer are arranged on the detection device.

Then, a gas detection phase is entered. The execution logic of the process is the same as that of steps 1-3, and the whole process generates corresponding signal values R1 ', R2 ' and R3 ', and after the detection is finished, the solenoid valve a13, the solenoid valve b34, the solenoid valve c23, the solenoid valve d44, the solenoid valve e54, the first air pump 35, the second air pump 45, the third air pump 55 and the fourth air pump 22 are all opened to exhaust the gas in the structures of the gas detection chamber 6 and the like. The first air pump 35, the second air pump 45, the third air pump 55 and the fourth air pump 22 are closed to enable the gas in the structures such as the gas detection chamber 6 and the like to reach a relative balance state with the outside, and after 1-2 seconds, the electromagnetic valve a13, the electromagnetic valve b34, the electromagnetic valve c23, the electromagnetic valve d44 and the electromagnetic valve e54 are closed.

For the 6 values generated in the above process, under a general air environment, the values of R1, R2 and R3 are very close (methanol, ethanol, acetone and ammonia gas are not contained in pure air), so that the air zero signal value is the average value of three numbers, i.e., R0 ═ (R1+ R2+ R3)/3. If air is doped with one or more of the above gases, deviation occurs among three signal values of R1, R2 and R3, and in the subsequent quantitative calculation process of gas concentration, normalization is required to be performed by taking R1, R2 and R3 as corresponding background values of R1 ', R2 ' and R3 '. The signal values for ammonia thus obtained were (R1 ' -R1) - (R2 ' -R2), and the signal value for acetone was (R3 ' -R3). These two signals can be used to correlate the concentration of ammonia and acetone gases in the exhaled breath of the subject and thereby assess the status of their food metabolism and the risk of developing diabetes and chronic renal failure.

In this embodiment, the detection device has the advantage of TiO₂The preparation method of the nano gas-sensitive material is simple and has low cost. The design of molecular sieve and gas circuit makes the TiO₂The deficiency of selectivity of the gas sensor is converted into the advantage of being capable of detecting more target gases, the quantitative analysis of the concentration of a plurality of gases can be completed by the same sensor at the same time, the detection environment for controlling and discharging interference signals is provided for the application of the similar semiconductor gas sensor, and the signal association and identification efficiency of the detection device to the target detection gas is improved.

Although the invention has been described in detail with respect to the general description and the specific embodiments, it will be apparent to those skilled in the art that modifications and improvements can be made based on the invention. Therefore, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. The expiration detection device is characterized by being based on TiO₂The breath detection device comprises an air inlet unit, an air outlet unit, a gas sensor, a first gas filtering unit, a second gas filtering unit, a third gas filtering unit and a gas detection chamber, wherein the air inlet unit, the air outlet unit, the first gas filtering unit, the second gas filtering unit and the third gas filtering unit are all communicated with the gas detection chamber, and the gas sensor is arranged in the gas detection chamber;

One end of the second input pipe is connected with the gas detection chamber, the other end of the second input pipe is connected with the second gas filter, and the second input pipe is provided with an electromagnetic valve d; the second outputOne end of the pipe is connected with the gas detection chamber, the other end of the pipe is connected with the second gas filter, and a second air pump is arranged on the second output pipe;

One end of the third input pipe is connected with the gas detection chamber, the other end of the third input pipe is connected with a third gas filter, and an electromagnetic valve e is arranged on the third input pipe; one end of the third output pipe is connected with the gas detection chamber, the other end of the third output pipe is connected with a third gas filter, and a third air pump is arranged on the third output pipe;

2. The breath test device as claimed in claim 1, wherein the air blowing valve comprises an air inlet passage, an air outlet passage, an air pressure control passage, a screw cap and a bearing ball, the air inlet passage, the air outlet passage and the air pressure control passage are communicated with each other, the air inlet passage is communicated with the air tap, the air outlet passage is communicated with the air test chamber, the bearing ball is disposed in the air pressure control passage, the bearing ball is used for indicating the pressure and the flow rate of the air blown by the tester, the screw cap is covered at the free end of the air pressure control passage, and the screw cap is used for controlling the opening and closing of the air pressure control passage.

3. The breath detection apparatus of claim 2, wherein the interface of the pressure control airway and the inlet or outlet airway is connected by a porous barrier.

4. The breath detection device of claim 2, wherein the weight of the weight bearing ball is not less than 10 grams, and an outer surface of the weight bearing ball is coated with an antimicrobial coating.

5. The breath test apparatus of claim 1, wherein the gas sensor operates at a temperature of about 250 ℃ to about 350 ℃ for a reaction time of about 10 seconds.

6. The breath detection apparatus of claim 1, wherein the gas detection chamber has a shape of a pentagonal prism, and five sides of the gas detection chamber are respectively connected to the gas inlet unit, the gas outlet unit, the first gas filtering unit, the second gas filtering unit, and the third gas filtering unit.

7. The breath detection device of claim 4, wherein an outer diameter of the insufflation valve is less than 3 cm.