阅读说明：本技术 一种金属容器内液体的检测装置及检测方法 (Detection device and detection method for liquid in metal container ) 是由 翟利 梁丽华 张旭红 刘晓超 徐圆飞 李保磊 何珍珍 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种金属容器内液体的检测装置及检测方法,属于安检技术领域,解决了现有技术中液体检测的识别率低、防尘防水差或使用寿命有限的问题之一。一种金属容器内液体的检测装置,包括加温模块和测温模块；所述加温模块用于对金属容器进行加热,使金属容器内的液体形成一个具有温度梯度的温度场；所述测温模块包括多个测温点,每个测温点与加温模块的距离均不相同,通过测量位于加温模块不同位置的液体温度值,得到各测温点间的温差值。本发明适用于金属容器内液体的检测。(The invention discloses a device and a method for detecting liquid in a metal container, belongs to the technical field of security inspection, and solves one of the problems of low identification rate, poor dust and water prevention or limited service life of liquid detection in the prior art. A detection device for liquid in a metal container comprises a heating module and a temperature measuring module; the heating module is used for heating the metal container to enable liquid in the metal container to form a temperature field with a temperature gradient; the temperature measuring module comprises a plurality of temperature measuring points, the distance between each temperature measuring point and the heating module is different, and the temperature difference value between the temperature measuring points is obtained by measuring the liquid temperature values at different positions of the heating module. The invention is suitable for detecting the liquid in the metal container.)

1. The device for detecting the liquid in the metal container is characterized by comprising a heating module and a temperature measuring module;

the heating module is used for heating the metal container to enable liquid in the metal container to form a temperature field with a temperature gradient;

the temperature measuring module comprises a plurality of temperature measuring points, the distance between each temperature measuring point and the heating module is different, and the temperature difference value between the temperature measuring points is obtained by measuring the liquid temperature values at different positions of the heating module.

2. The apparatus according to claim 1, wherein the temperature measuring module comprises a first temperature measuring point and a second temperature measuring point.

3. The apparatus for detecting the liquid in the metal container according to claim 1, wherein the apparatus further comprises a metal detection module and a microprocessor module;

the metal detection module is used for detecting whether a metal container exists in the detection area;

after the metal detection module detects the metal container, the state information is sent to the microprocessor module, and the microprocessor module controls the heating module to heat the metal container.

4. The apparatus for detecting a liquid in a metal container according to claim 3, wherein said apparatus further comprises an alarm display module.

5. The apparatus for detecting a liquid in a metal container according to claim 3, wherein the warming module comprises a plurality of heating resistors and an elastic member;

the heating resistors are arranged on one surface of the elastic piece, the elastic piece is used for supporting the heating resistors, and the shape of the elastic piece can be matched with that of the surface of the metal container;

when in use, the surface of the elastic piece provided with the heating resistor is contacted with the metal container.

6. The apparatus for detecting the liquid in the metal container according to the claims 1-5, wherein the temperature measuring module comprises a temperature sensor and a signal amplifier;

the temperature sensor is a thermistor or a platinum resistor;

and the signal amplifier converts the variation of the temperature sensor into a voltage signal which can be detected by a microprocessor module.

7. The apparatus for detecting a liquid in a metal container according to claim 4, wherein the alarm display module comprises an indicator lamp, a buzzer and a liquid crystal display.

8. A method for detecting liquid in a metal container is characterized by comprising the following steps:

placing the metal container into a detection area, and sending a state signal to a microprocessor module after the metal detection module detects the metal container;

the microprocessor module controls the heating module to heat the metal container;

the temperature measuring module detects and measures temperature values of the liquid at different distances from the heating module and sends temperature signals to the microprocessor module;

the microprocessor module calculates the temperature difference value between different measurement positions, calculates the heat conductivity coefficient under different environmental temperatures or the initial temperature of the measured liquid, and judges the property of the liquid.

9. The method according to claim 8, wherein the heat conductivity is calculated by the formula:

(T2-T1)*t*k*Δs＝-(L2-L1)*Q

in the formula, T1 is a temperature value of a first temperature measuring point, T2 is a temperature value of a second temperature measuring point, T is heating time, k is a thermal conductivity coefficient of a measured liquid, Δ s is a constant, L1 is a distance between the first temperature measuring point and the heating module, L2 is a distance between the second temperature measuring point and the heating module, Q is heat flowing through Δ s, and a minus sign indicates that heat is transferred in a direction in which the temperature decreases.

10. The method for detecting a liquid in a metal container according to claim 8,

when the heat conductivity coefficient of the liquid to be detected is lower than the threshold value, judging that the liquid to be detected is dangerous, sending a danger prompt sound by the buzzer, and simultaneously displaying a danger prompt by the liquid crystal;

when the heat conductivity coefficient of the liquid to be detected is above the threshold value, the liquid is judged to be safe liquid, the buzzer sends out a safety prompt sound, and meanwhile, the liquid crystal displays a safety prompt.

Technical Field

The invention relates to the technical field of security inspection, in particular to a device and a method for detecting liquid in a metal container.

Background

In recent years, the requirement for identifying dangerousness of liquid carried by citizens in the field of security inspection is higher and higher, and the range of identifying the liquid is wider and wider; hand-held and table type dangerous liquid detectors of various types are also available in the market, and can detect liquid in a non-metal container or a metal container.

Wherein, the detection technology of the liquid in the metal container mainly adopts a heat conduction method. The heat conduction method is characterized in that the characteristics of different heat conduction coefficients of liquids with different properties are utilized, the temperature curve of the liquid is changed along with the heating time by adopting a heating film under the condition of adding the same heating condition, and the heat conduction coefficient of the liquid is calculated by collecting the temperature change data of the detected liquid at a fixed time point, so that the properties of the liquid are judged.

When the ambient temperature or the liquid temperature deviates from the correction point to a large temperature, the situation of reduced identification rate or wrong identification can occur due to the difference of heat dissipation conditions by a heat conduction method adopted by the conventional scheme; secondly, the heating film is in direct contact with the wall of the container, so that the dustproof and waterproof functions of the equipment are limited; the heating film has a limited service life and is easily damaged under the influence of power.

Disclosure of Invention

In view of the above analysis, the present invention is directed to a device and a method for detecting liquid in a metal container, which are used to solve one of the problems of low recognition rate, poor dust and water resistance, and limited service life of the prior art in detecting liquid by using a heat conduction method.

The purpose of the invention is mainly realized by the following technical scheme:

on one hand, the invention provides a detection device for liquid in a metal container, which comprises a heating module and a temperature measuring module;

the heating module is used for heating the metal container to enable liquid in the metal container to form a temperature field with a temperature gradient;

the temperature measuring module comprises a plurality of temperature measuring points, the distance between each temperature measuring point and the heating module is different, and the temperature difference value between the temperature measuring points is obtained by measuring the liquid temperature values at different positions of the heating module.

In one possible design, the thermometry module includes a first thermometry point and a second thermometry point.

In one possible design, the detection device further comprises a metal detection module and a microprocessor module;

the metal detection module is used for detecting whether a metal container exists in the detection area;

after the metal detection module detects the metal container, the state information is sent to the microprocessor module, and the microprocessor module controls the heating module to heat the metal container.

In one possible design, the detection device further includes an alarm display module.

In one possible design, the warming module comprises a plurality of heating resistors and an elastic member;

the heating resistors are arranged on one surface of the elastic piece, the elastic piece is used for supporting the heating resistors, and the shape of the elastic piece can be matched with that of the surface of the metal container;

when in use, the surface of the elastic piece provided with the heating resistor is contacted with the metal container.

In one possible design, the thermometry module includes a temperature sensor and a signal amplifier;

the temperature sensor is a thermistor or a platinum resistor;

and the signal amplifier converts the variation of the temperature sensor into a voltage signal which can be detected by a microprocessor module.

In one possible design, the alarm display module includes an indicator light, a buzzer, and a liquid crystal display.

In one possible design, the warming module further comprises an electronic switch, which is controlled by the microprocessor module.

On the other hand, the invention also provides a method for detecting the liquid in the metal container, which comprises the following steps:

placing the metal container into a detection area, and sending a state signal to a microprocessor module after the metal detection module detects the metal container;

the microprocessor module controls the heating module to heat the metal container;

the temperature measuring module detects and measures temperature values of the liquid at different distances from the heating module and sends temperature signals to the microprocessor module;

the microprocessor module calculates the temperature difference value between different measurement positions, calculates the heat conductivity coefficient under different environmental temperatures or the initial temperature of the measured liquid, and judges the property of the liquid.

In one possible design, the thermal conductivity is calculated by the formula:

(T2-T1)*t*k*Δs＝-(L2-L1)*Q

in the formula, T1 is a temperature value of a first temperature measuring point, T2 is a temperature value of a second temperature measuring point, T is heating time, k is a thermal conductivity coefficient of a measured liquid, Δ s is a material cross-sectional area, L1 is a distance between the first temperature measuring point and a heating module, L2 is a distance between the second temperature measuring point and the heating module, and Q is heat flowing through Δ s.

In one possible design, when the heat conductivity coefficient of the liquid to be detected is lower than a threshold value, the liquid to be detected is judged to be dangerous, a buzzer sends out a danger prompt sound, and meanwhile, a Liquid Crystal Display (LCD) displays a danger prompt;

when the heat conductivity coefficient of the liquid to be detected is above the threshold value, the liquid is judged to be safe liquid, the buzzer sends out a safety prompt sound, and meanwhile, the liquid crystal displays a safety prompt.

Compared with the prior art, the invention can realize at least one of the following beneficial effects:

a) the invention realizes the detection of the liquid properties based on the difference of the heat conductivity coefficients of the liquids with different properties. The heat conduction is usually from a high temperature object to a low temperature object, and the heat conductivity coefficient of the liquid can be calculated by measuring the temperature difference between the liquid temperature values at different positions of the heating module and the temperature measuring points, so that the liquids with different properties can be measured. The influence of the ambient temperature and the liquid temperature on the heat conductivity coefficient and the test result is well solved, the accuracy of the test result is improved, and meanwhile, the anti-interference capability is improved.

b) The heating module adopts the hard heating resistor, so that the heating module is not easy to damage, and the service life of the heating module is prolonged.

c) In order to avoid the hard heating resistor from being not attached to the surface of the metal container, a plurality of heating resistors are arranged, and a plurality of smaller heating resistors are spliced into a larger shape. The heating resistors are arranged on one surface of the elastic piece, the elastic piece is used for supporting the heating resistors, and the elastic piece can be matched with the surface shape of the metal container.

d) In order to calculate the distance between the heating module and the plurality of temperature measuring points conveniently, the heating module and the plurality of temperature measuring points are on the same straight line.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating the particular invention and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout the figures.

FIG. 1 is a schematic structural diagram of a detection device;

FIG. 2 is a schematic view of an application of the detecting device of the present invention;

fig. 3 is a schematic diagram of a warming module and a temperature measuring point.

Reference numerals:

1-a warming module; 2-a temperature measuring module; 201-a first temperature measurement point; 202-a second temperature measurement point; 3-a microprocessor module; 4-a metal detection module; 5-an alarm display module; 6-liquid level.

Detailed Description

The preferred invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the description serve to explain the principles of the invention.

Spatially relative terms such as "below," "beneath," "above," "over," and the like may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, when the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below, as well as other orientations of the device.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

A detection device for liquid in a metal container is shown in figures 1 and 2 and comprises a heating module and a temperature measuring module; the heating module is used for heating the metal container to enable liquid in the metal container to form a temperature field with a temperature gradient; the temperature measuring module comprises a plurality of temperature measuring points, the distance between each temperature measuring point and the heating module is different, and the temperature difference value between the temperature measuring points is obtained by measuring the temperature value of the liquid at different positions away from the heating module.

The invention realizes the detection of the liquid properties based on the difference of the heat conductivity coefficients of the liquids with different properties. The heat conduction is usually from a high temperature object to a low temperature object, and the heat conductivity coefficient of the liquid can be calculated by measuring the temperature difference between the liquid temperature values at different positions of the heating module 1 and the temperature measuring points, so that the liquids with different properties can be measured. The influence of the environment temperature and the liquid temperature on the heat conductivity coefficient on the test result is well solved, the accuracy of the test result is improved, and meanwhile, the anti-interference capability is improved.

Illustratively, the temperature measuring module 2 includes a first temperature measuring point 201 and a second temperature measuring point 202, the first temperature measuring point 201 and the second temperature measuring point 202 have different distances from the warming module 1, and the first temperature measuring point 201 and the second temperature measuring point 202 obtain a temperature difference value between the temperature measuring points by measuring liquid temperature values at different positions of the warming module 1.

In order to facilitate the calculation of the distance between the warming module 1 and the plurality of temperature measuring points, it is preferable that the warming module 1 and the plurality of temperature measuring points are on the same straight line.

The detection device also comprises a metal detection module 4, a microprocessor module 3 and an alarm display module 5. The metal detection module 4 is used for detecting whether a metal container exists in the detection area, and the microprocessor module 3 mainly realizes the acquisition, operation and data processing of signals and the control of an external module. After the metal detection module 4 detects the metal container, the state information is sent to the microprocessor module 3, and the microprocessor module 3 controls the heating module 1 to heat the metal container. Meanwhile, the microprocessor module 3 controls the temperature measuring module 2 to detect the temperature values of a plurality of temperature measuring points near the heating module 1; calculating the heat conductivity coefficient of the liquid according to the temperature of each temperature measuring point, and processing to obtain the property of the liquid; and reporting the test result by controlling the alarm display module 5.

Preferably, the warming module 1 includes a heating resistor and an elastic member. In order to solve the problems that the heating film in the prior art is limited in service life and easy to damage, the heating module 1 in the invention adopts a hard heating resistor, so that the heating module is difficult to damage, and the service life of the heating module 1 is prolonged.

In order to avoid the hard heating resistor from being not adhered to the surface of the metal container, preferably, a plurality of heating resistors are arranged, and a plurality of smaller heating resistors are spliced into a larger shape. The heating resistors are arranged on one surface of the elastic piece, the elastic piece is used for supporting the heating resistors, and the elastic piece can be matched with the surface shape of the metal container; when the heating resistor is used, the surface of the elastic piece, which is provided with the heating resistor, is contacted with the metal container, so that the heating resistor is attached to the surface of the metal container.

The warming module 1 also comprises an electronic switch, and the electronic switch is controlled by the microprocessor module 3 to heat the metal container of the liquid to be measured.

The temperature measuring module 2 comprises temperature sensors and signal amplifiers, and each temperature measuring point corresponds to 1 temperature sensor and 1 signal amplifier. The temperature sensor is a thermistor or a platinum resistor; the signal amplifier converts the variation of the temperature sensor into a voltage signal detectable by the microprocessor module 3.

In the prior art, a thermocouple is generally used for measuring temperature and is limited by the volume of a detection structure, a protection shell is not manufactured on the thermocouple, the temperature is directly measured through a bare electrode with a small contact area, and the waterproof capability is weak; this application temperature sensor is thermistor or platinum resistance, and the volume is very little, can be structural can carry out dustproof and waterproof processing to the outside parcel one deck heat-conducting glue of temperature sensor, has solved the poor problem of current equipment dustproof and waterproof performance.

The heating module 1 and the temperature measuring module 2 are arranged at lower positions so as to ensure that the heating module 1 and the temperature measuring module 2 are positioned below the liquid level 6 when liquid in the metal container is detected.

The alarm display module 5 comprises an indicator light, a buzzer and a liquid crystal display and is used for displaying various states and whether the liquid property is dangerous or not in the working process of the detection device.

Illustratively, the detection device comprises a detection ready state, a detection-in-progress state and a detection result display state, and the indicator light indicates the current detection flow state through different colors. The liquid can be displayed to be safe or dangerous in the detection result display state, at the moment, the buzzer can send out a safety or dangerous prompt sound, and meanwhile, the liquid crystal display is used for displaying a safety or dangerous prompt.

A method for detecting liquid in a metal container comprises the following steps:

the metal container is placed in a detection area, and the metal detection module 4 sends a state signal to the microprocessor module 3 after detecting the metal container;

the microprocessor module 3 controls the heating module 1 to heat the metal container;

the temperature measuring module 2 detects and measures temperature values of the liquid at different distances from the heating module 1 and sends temperature signals to the microprocessor module 3;

the microprocessor module 3 calculates the heat conductivity coefficient under different environmental temperatures or the initial temperature of the liquid to be measured by calculating the temperature difference value between different measurement positions, and judges the property of the liquid.

It should be noted that, in order to calculate the distance between the heating module 1 and the plurality of temperature measuring points, the heating module 1 and the plurality of temperature measuring points are on the same straight line.

The calculation method of the thermal conductivity coefficient is as follows:

the warming module 1 is in a straight line with the first temperature measuring point 201 and the second temperature measuring point 202, as shown in fig. 3, the distance from the warming module 1 to the first temperature measuring point 201 is L1, and the distance from the warming module 1 to the second temperature measuring point 202 is L2. After the heating of the time T, the temperature of the warming module 1 is T0, the temperature measured by the first temperature measuring point 201 is T1, the temperature measured by the second temperature measuring point 202 is T2, and T0> T1> T2.

According to the fourier law, the heat per unit time passing through a given section is proportional to the rate of change of temperature and the area of the section in the direction perpendicular to the section, while the direction of heat transfer is opposite to the direction of temperature increase.

In the case of one-dimensional stable thermal conduction, the fourier law can be expressed in the form:

in the formula (I), the compound is shown in the specification,expressed as heat transferred by as per second,is the temperature gradient in accordance with the direction of heat flow, the negative sign indicates that heat is transferred in the direction of decreasing temperature, and the proportionality coefficient k is the thermal conductivity of the material. Δ s is ideally an approximately spherical area between the radius of L1 and L2 from the warming module 1, and Δ s is a constant since the distances of L1 and L2 from the warming module 1 are fixed.

The same measured liquid is heated for time t, integration is carried out on two sides of the formula (1), and the measured liquid is obtained at a first temperature measuring point 201 and a second temperature measuring point 202:

(T1-T0)*t*k*Δs＝-L1*Q (2)

(T2-T0) T k Δ s-L2Q (3) formula (2) (3) is subtracted:

(T2-T1)*t*k*Δs＝-(L2-L1)*Q (4)

in the test, the heating power and time are constant, and the distance between the temperature measuring points is constant, so that the temperature difference between the two temperature measuring points is inversely proportional to the thermal conductivity of the liquid for different liquids. The larger the temperature difference, the smaller the thermal conductivity of the liquid, and the smaller the temperature difference, the larger the thermal conductivity of the liquid. As shown in Table 1, the thermal conductivity of water or a near water solution is higher than that of other common hazardous liquids, and the thermal conductivity of water is about 0.6W/mK. Setting a threshold value according to the heat conductivity coefficient of water, comparing the heat conductivity coefficient of the liquid to be detected in the metal container with the threshold value, judging that the liquid to be detected is dangerous when the heat conductivity coefficient of the liquid to be detected is lower than the threshold value, sending a danger prompt sound by a buzzer, and simultaneously displaying a danger prompt by a liquid crystal; when the heat conductivity coefficient of the liquid to be detected is above the threshold value, the liquid is judged to be safe liquid, the buzzer sends out a safety prompt sound, and meanwhile, the liquid crystal displays a safety prompt. Illustratively, the threshold is set at 0.5W/mK.

As can be known from the formula (4), the method is irrelevant to the ambient temperature and only relevant to the temperature difference between two heated temperature measuring points, so that the influence of the ambient temperature on the test result is well solved.

TABLE 1 thermal conductivity of several common liquids

Common metal containers are made of aluminum or iron; according to the requirement of the maximum wall thickness of the detectable metal container in national standard, the thickness of iron is more than or equal to 0.2mm, and the thickness of aluminum is more than or equal to 0.3 mm. The aluminum can body is usually 3004 aluminum, and the thermal conductivity of the aluminum can body is about 163W/mK; the iron container body is made of tinplate, and the thermal conductivity of the tinplate is about 80W/mK; water is the highest thermal conductivity of all fluids, about 0.6W/mK. It can be seen that the thermal conductivity of common metal packages is much higher than that of water, and the metal container walls are thin, and in practical tests, the effect of the container walls on the liquid is negligible.

If the wall thickness of the detected metal container exceeds the national standard requirement, the wall thickness influences the temperature conduction, so that the temperature difference between the temperature measuring points is reduced, and the testing precision is influenced, preferably, a third temperature measuring point is added, the distance between the third temperature measuring point and the first temperature measuring point 201 is larger, a larger temperature difference can be detected, the liquid thermal conductivity can be calculated more accurately, and the temperature value of the second temperature measuring point 202 is taken as an auxiliary reference.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.