CN111965313A

CN111965313A - Food specific volume measuring instrument and detection method thereof

Info

Publication number: CN111965313A
Application number: CN202010856714.8A
Authority: CN
Inventors: 俞越
Original assignee: China Inspection Group Gongxin Security Technology Co ltd
Current assignee: China Inspection Group Gongxin Security Technology Co ltd
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2020-11-20
Anticipated expiration: 2040-08-24
Also published as: CN111965313B

Abstract

The invention relates to a food specific volume measuring instrument and a detection method thereof, belonging to detection equipment. The technical scheme adopted by the invention is as follows: including the box of rectangle, the box leading flank is equipped with food and places the mouth, food is placed the mouth and is set up the air-tight door, be equipped with L container and S container in the box, food is placed a mouthful intercommunication and L container, the S container is in L container top, the volume of S container is less than the L container, the L container is used for placing the measured object article, and place the mouth with food and communicate with each other, L container and S container are linked together, and set up the electromagnetism butterfly valve in the position of being linked together, one side of L container and S container is the gas cylinder, be equipped with standard gas bottle in the gas cylinder and be linked together with the S container, and set up the relief pressure valve on being linked together the. The invention develops an integrated food specific volume detection device; the specific volume of food cream cake, instant noodles and the like which cannot be directly measured by the traditional method can be measured, the food cannot be polluted, the specific volume of the food cannot be influenced, and meanwhile, the instrument is easy to carry.

Description

Food specific volume measuring instrument and detection method thereof

Technical Field

The invention relates to a food specific volume measuring instrument and a detection method thereof, belonging to detection equipment.

Background

In the food inspection process, it is necessary to: the specific volume of food such as steamed bread, biscuits, ice cream and the like is measured. The specific volume is the size (mL/l00g or mL/g) of a unit mass of a solid food. Bread specific volume is too small, internal tissue is not uniform, and flavor is not good; too large specific volume, too much volume expansion, rough internal structure and reduced bread quality. Wherein, the bread specific volume specified in GB/T20981-2007 is less than or equal to 7.0mL/g, and the wheat flour steamed bread specific volume specified in GB/T21118-2007 is more than or equal to 1.7 mL/g. The measurement of the specific volume of food is a difficult point of instruments because of irregular and inconsistent food surfaces and attachments such as sugar cream on the surfaces. Currently, the bread size is measured by filling with a granular filling (rapeseed), which is also weighed and finally the specific volume is determined.

However, the particulate filler is susceptible to contamination by and to contamination of the food product during use of conventional instruments. Meanwhile, the filler extrudes food to different degrees due to the action of gravity, and particularly, measurement errors can be caused by the fluffy food. In addition, zero point detection is needed before measurement, the broken slag of the food to be measured is cleaned after the experiment, impurities are removed, and the filler (rapeseed) is cleaned and dried, so that the precision can greatly float due to the variety of the food. Three-dimensional laser scanning type instruments can cause large errors due to different light reflecting regions on the surfaces of foods, and cannot measure the specific volumes of complex foods such as instant noodles and the like. Therefore, a specific volume tester special for food, which is convenient to detect, suitable for processing food with complex appearance, environment-friendly, safe and reliable, is needed in the market. The invention solves the problems, does not use traditional fillers, avoids a complicated cleaning process and does not pollute food.

Disclosure of Invention

The invention provides a food specific volume measuring instrument and a detection method thereof, which realize integrated food specific volume measurement without manual intervention and simultaneously avoid the problem of pollution to food to be detected.

In order to achieve the purpose, the invention adopts the technical scheme that:

the food specific volume measuring instrument comprises a rectangular box body, a food placing opening is formed in the front side face of the box body, a gas tight door is arranged at the food placing opening, an S container and an L container are arranged in the box body, the S container is positioned above the L container, the volume of the S container is one fourth of that of the L container, the L container is communicated with the S container, two electromagnetic butterfly valves are arranged at the communicated positions, gas cylinders are arranged on one sides of the outer portions of the L container and the S container, 99.999% purity octafluorocyclobutane is filled in the gas cylinders and is used as standard gas, the gas cylinders are communicated with the S container, a pressure reducing valve, an electromagnetic flow valve and a constant temperature vaporizer are arranged on a communicated pipeline, a vacuum pump is arranged on the other side of the outer portions of the L container and the S container, the vacuum pump is communicated with the S container through a metal conduit, a vacuum pump, the L container and the S container are respectively provided with a heat insulation structure and a state calibration sensor, the L container is provided with a food weight sensor and an NDIR sensor, and the S container is provided with a temperature compensation adjusting device.

Preferably, the outer wall of the S container is provided with an S container temperature compensation adjusting device for controllably adjusting the temperature of gas in the S container, the S container temperature compensation adjusting device is coated by an S container insulating layer to form an S container insulating structure, and the S container internal state calibration sensor comprises an S container temperature sensor and an S container air pressure detection sensor.

Preferably, the L container is provided with a food placing opening, the heat preservation structure of the L container is formed by an L container heat preservation layer covered by the outer surface, the calibration sensor for the state in the L container comprises an L container air pressure detection sensor and an L container temperature detection sensor, a food weight sensor arranged in the L container is suspended on a food placing basket, the food placing basket is provided with a unique number corresponding to an instrument, the food placing basket is used for placing tested food, the NDIR sensor is a high-precision octafluorocyclobutane NDIR sensor, the sensing end of the octafluorocyclobutane NDIR sensor is positioned in the L container, and the volume concentration of output gas is measured through a non-dispersive infrared technology.

Preferably, the number of the electromagnetic butterfly valves between the L container and the S container is two, a miniature convection fan is arranged at the position of an air inlet and an air outlet of one electromagnetic butterfly valve, an airflow deflection plate is arranged at the position of the air inlet and the air outlet of the other electromagnetic butterfly valve, the valve clack in the electromagnetic butterfly valve rotates around the valve shaft to be opened and closed, the valve shaft is sealed with the outside, and a corresponding heat insulation structure is further arranged on the outer side of the electromagnetic butterfly valve.

Preferably, the volume fine-tuning device comprises a cylindrical adjusting column and a threaded telescopic rod at the rear part of the adjusting column, the cylindrical adjusting column extends into the L container or the S container, the threaded telescopic rod rotates to drive the cylindrical adjusting column to extend into or out of the L container or the S container, and the adjusting column is provided with a damping ring and a sealing ring to realize sealing.

Preferably, the front side surface of the box body is also provided with a gas cylinder cabin door, a display screen, a working state indicator lamp and a control button, the upper side surface of the box body is provided with a handle, the oblique side surface of the box body is provided with a foot pad, the airtight door is provided with a transparent observation window, and the inside of the box body is provided with a control circuit.

Preferably, one side of the airtight door is provided with a hinge connected with the box body, and the rest edge of the airtight door is provided with a plurality of rotary locking buckles for fastening and sealing the airtight door on the food placing opening of the box body.

Further preferably, the control circuit comprises a single chip microcomputer control module in the box body, a control button, an L container air pressure detection sensor, an L container temperature detection sensor, an S container temperature sensor, an S container air pressure detection sensor, a food weight sensor, an octafluoro cyclobutane NDIR sensor are connected to the input end of the single chip microcomputer control module through a line, a display screen, a vacuum pump valve, an electromagnetic butterfly valve, a micro convection fan, an S container temperature compensation adjusting device, an electromagnetic flow valve, a constant temperature vaporizer and a working state indicator lamp are connected to the driving output end of the single chip microcomputer control module through a lead.

The method for measuring the specific volume by using the food specific volume measuring instrument comprises the following steps,

1) placing food into the food placing basket of the L container through the airtight door, closing the airtight door and detecting the airtight condition to ensure the airtight effect;

2) closing all the electromagnetic valves, detecting whether the environment temperature is in a proper working temperature range, detecting the content of the octafluorocyclobutane in the L container, and performing the next step if the content meets the requirements;

3) weighing food quality, recording the food quality as M, opening a vacuum pump valve after the food quality is finished, starting a two-stage vacuum pump, performing vacuum pumping operation on an S container, and when an air pressure sensor of the S container detects that the vacuum degree reaches 2 multiplied by 10^-1When Pa, the vacuum pump is closed, the vacuum pump valve is closed, and the next step is carried out;

4) the electromagnetic flow valve is opened, the constant-temperature vaporizer starts to work, the outlet temperature of the constant-temperature vaporizer connected with the S container is kept to be slightly lower than the temperature of the L container, and the maximum temperature difference does not exceed 10 ℃;

5) when an S container air pressure sensor detects that the air pressure value of an S container is equal to 90-98% of the air pressure of an L container, closing an electromagnetic flow valve, delaying for 60-120S, then detecting the difference between the temperature of the S container and the temperature of the L container, adjusting the temperature of the S container through a temperature compensation adjusting device, detecting the difference between the detected air pressure of the S container and the detected air pressure of the L container again when the temperature difference is less than +/-0.05 ℃, controlling the temperature of the constant-temperature vaporizer to be equal to the temperature of the L container, gradually supplementing air until the air pressure of the S, L container is consistent, and closing the electromagnetic flow valve;

6) opening a double-chamber electromagnetic butterfly valve, delaying for 2 seconds, then taking the values of the air pressure sensors in the S container and the L container, respectively comparing the values with the values before the electromagnetic butterfly valve is opened, and carrying out the next step when the air pressure fluctuation is less than 0.2%;

7) starting a micro convection fan, determining the wind speed and the circulating air volume according to the food variety by adopting a constant rotating speed of the micro convection fan, and then powering off the micro convection fan;

8) starting a high-precision octafluorocyclobutane NDIR sensor to measure the volume concentration of octafluorocyclobutane, and recording the volume concentration as N%;

9) the total volume sum V of the S container, the pipeline communicated with the S container and the valve when the butterfly valve stored in the adjusting system is closed_STotal volume sum V of L container and valve for communicating L container_LThe total volume is calibrated by using liquid before leaving a factory, the numerical value is stored in a single chip microcomputer, k is a compensation coefficient, and the compensation coefficient is not adopted for a scene with the measurement result accuracy requirement being more than 1 level;

10) using a single chip microcomputer to calculate, wherein the formula of the specific volume of the food is P_F=[V_S+V_L-（V_S÷N%）]X k/M to obtain the specific volume P of food_F。

The invention has the advantages that:

an integrated special detection device for the specific volume of the food without manual intervention is developed, and a new scheme is provided for measuring the specific volume of the food; the specific volume of the food (cream cake, instant noodles and the like) which cannot be directly measured by the traditional method can be measured, the food cannot be polluted and not polluted by the food, the specific volume of the food cannot be influenced, and meanwhile, the instrument has the advantages of good portability and easiness in carrying.

The technical personnel creatively and preferably select the use of the octafluorocyclobutane as the measuring gas, and a new scheme is provided for measuring the volume of the food, and the method has obvious advantages compared with other schemes.

Meanwhile, the instrument has the characteristics of simple operation, high accuracy, reasonable structure and easiness in operation, can be rapidly popularized after being marketed, and can be used for pulling the development of related industrial chains and promoting the conversion of new and old kinetic energy in the detection and inspection industry.

Drawings

Figure 1 is an external structural view of the present invention,

figure 2 is an external front side view of the present invention,

figure 3 is a top view of the outer structure of the present invention,

figure 4 is a side view of the external structure of the present invention,

figure 5 is an internal structural view of the present invention,

fig. 6 is a control module connection diagram of the present invention.

Reference numerals: 1. a box body, 2, a food placing opening, 3, an airtight door, 4, an L container, 5, an S container, 6, a vacuum pump, 7, an L container volume fine-tuning device, 8, a gas cylinder, 9, an S container volume fine-tuning device, 10 food, 101, a gas cylinder cabin door, 102, a display screen, 103, a working state indicating lamp, 104, a control button, 105, a lifting handle, 106, a foot pad, 107, a transparent observation window, 108, a hinge, 109, a rotary locking buckle, 110, a detachable side plate, 111, a gas cylinder cabin door lock, 112, a cabin door closing sensor, 401, an L container air pressure detection sensor, 402, an L container temperature detection sensor, 403, a high-precision octafluorocyclobutane NDIR sensor, 404, a food placing basket, 405, a food weight sensor, 406, an electromagnetic butterfly valve, 407, an air flow deflection plate, 408, an L container heat-insulation layer, 409, a miniature convection fan, 410, an electromagnetic valve state, 501. the system comprises an S container heat insulation layer, 502 and S container temperature sensors, 503 and S container air pressure detection sensors, 504 and S container temperature compensation adjusting devices, 601, a metal guide pipe, 602, a vacuum pump valve, 701, a cylindrical adjusting column, 702, a threaded telescopic rod, 703, a damping ring, 704, a sealing ring, 801, a pressure reducing valve 802, an electromagnetic flow valve, 803 and a constant temperature vaporizer.

Detailed Description

The following further illustrates the specific structure of the present invention:

the external structure of the device is shown in figures 1-4, a rectangular box body 1 is provided with a food placing opening 2, an air bottle cabin door 101, a display screen 102, a working state indicator light 103 and a control button 104 on the front side surface of the box body 1, the food placing opening 2 is provided with an airtight door 3, one side of the airtight door 3 is provided with a hinge 108 to be connected with the box body 1, and the edge of the airtight door 3 is provided with 4 rotary locking buckles for fastening and sealing the cabin door. The display screen 102 and the control buttons are arranged on a display control panel, the display screen is a color LCD display screen and is used for displaying relevant test information, and the control buttons are used for turning on and off an instrument and adjusting parameters. The working state indicator lamp can display the working state and the fault condition, and the cabin door is prevented from being opened by mistake during working. The gas cylinder cabin door is provided with a gas cylinder cabin door lock and a cabin door closing sensor. The side of the box body is respectively provided with 2 detachable side plates for internal maintenance, the upper part of the instrument is provided with a lifting handle for movement, the lower part of the instrument is provided with a foot pad for preventing vibration, and the rear part of the instrument is also provided with a power line and a USB data line interface.

The internal structure of the invention is shown in fig. 5, and two containers with unequal sizes are provided. Wherein, the Large Large Container is abbreviated as L-Container, and the Small Container is abbreviated as S-Container. And the S container is arranged above the L container, the volume of the S container is one fourth of that of the L container, the larger L container is used for placing the food to be measured, the L container does not bear pressure and is equal to the external air pressure when the food is placed, and the S container is communicated with the L container in the measuring working stage. S, L the volume of the container and the structure communicating with it is a fixed value.

Wherein, the preferred 316L stainless steel material of S container, L container material to have the heat preservation, the L container is complete airtight cabin, and food is placed mouthful 2 department and is set up the air-tight door, and container and door all are provided with the heat preservation. The L container has a complete airtight structure, and can effectively prevent measurement errors caused by fluctuation of external airflow. The basket is placed to built-in unsettled food, and food is placed the basket and is not contacted with L container inner wall, and the edge is placed on a plurality of food weight sensor of container inner wall, and every instrument matches only food and places the basket and have the serial number, and food is placed the frame aperture and need be greater than 3mm, changes food and places the basket and need return the factory and calibrate container inner space size.

The S container is provided with a temperature compensation adjusting device and a volume fine-tuning device. The temperature compensation adjusting device is attached between the wall of the S container and the heat insulation layer and used for adjusting the temperature in the S container. The L container is provided with a volume fine-tuning device.

The volume fine-tuning device consists of a cylindrical adjusting column, a sealing ring, a threaded telescopic rod and a damping ring. The cylindrical adjusting column traverses the container wall and is sealed with the container wall by two O-shaped sealing rings. The inner space of the fine-tuning container inserted into the container is adjusted by rotating the tail end of the threaded telescopic rod, and the damping ring is made of rubber, so that the telescopic rod is prevented from being screwed accidentally. The volume fine-tuning device is used for fine tuning when leaving a factory or calibrating a product, an ordinary user does not need to adjust when reusing the volume fine-tuning device, the volume fine-tuning device is mainly used for compensating errors in the production process of a container, differences of an electromagnetic butterfly valve, differences of food placing baskets and internal space errors caused by the influence of a sensor, and the size of the internal space is finely adjusted and compensated.

Still be equipped with the gas circuit device in the box: comprises a gas cylinder filled with standard substances, a pressure reducer, an electromagnetic flow valve, a constant-temperature vaporizer, a double-chamber electromagnetic butterfly valve, a micro convection fan, an airflow deflection plate, a vacuum pump valve, a double-stage vacuum pump and a metal conduit. The gas bottle 8 is communicated with the S container, a pressure reducing valve 801, an electromagnetic flow valve 802 and a constant temperature vaporizer 803 are arranged on a communicated pipeline, and the other side of the L container and the S container is provided withVacuum pump6, the vacuum pump 6 is communicated with the S container through a metal conduit 601, a vacuum pump valve 602 is arranged on the metal conduit 601, and the vacuum pump is a double-stage vacuum pump. Two groups of electromagnetic butterfly valves 406 are arranged at the communicated positions of the L container and the S container, wherein the constant-temperature vaporizer is controlled by the integrated control module to adjust the gas outlet temperature of the gas cylinder. The micro convection fan air flow is blown to the direction of the S container from the L container through the electromagnetic butterfly valve, and the air returns to the L container through the air flow deflection plate through the other electromagnetic butterfly valve. The standard substance is stored in a 2L gas cylinder, and the gas components are as follows: c₄F₈(octafluorocyclobutane), CSS number 115-25-3, gas purity: 99.999% of colorless, tasteless, nontoxic and noncombustible gas. The gas cylinder is provided with a manual valve and is opened before use, one end of the pressure reducer is connected with a gas cylinder connector, the other end of the pressure reducer is connected with an electromagnetic flow valve, and one end of the electromagnetic flow valve is connected with the constant-temperature vaporizer.

The two containers are also provided with a high-precision detection device, in particular an S container temperature sensor 502 and an S container air pressure detection sensor are also arranged in the S container. An L container air pressure detection sensor 401, an L container temperature detection sensor 402 and a high-precision octafluorocyclobutane NDIR sensor 403 are arranged in the L container. The temperature sensor is arranged at the center of the S container and the L container, and the sensing end of the air pressure sensor is respectively positioned in the S container and the L container and sealed with the container wall. And the S container air pressure detection sensor is of a vacuum negative pressure resistant type.

The sensing end of the high-precision octafluorocyclobutane NDIR sensor is positioned in the L container, the volume concentration is measured by using a non-dispersive infrared technology, specifically, monochromatic light of one or more specific wave bands is controlled to pass through octafluorocyclobutane gas, gas molecules absorb the gas, an absorption relation is obtained by Lambert-beer absorption law, and the output volume concentration is calculated.

A single-chip microcomputer control module is arranged in the box body and used for controlling the operation of the whole device, the connection relation between each component and the single-chip microcomputer control module is shown in fig. 6, a control button 104, an L container air pressure detection sensor 401, an L container temperature detection sensor 402, an S container temperature sensor 502, an S container air pressure detection sensor, a food weight sensor 405, a high-precision octafluorocyclobutane NDIR sensor 403 and an electromagnetic valve state sensor 410 are connected to the input end of the single-chip microcomputer control module through lines, and a display screen 102, a vacuum pump 6, a vacuum pump valve 602, an electromagnetic butterfly valve 406, a micro convection fan, an S container temperature compensation and adjustment device 504, an electromagnetic flow valve 802, a constant-temperature vaporizer 803 and a working state indicator lamp 103 are connected to the output.

This device carries out food volume measurement work flow:

1) pressing the control button, selecting the measuring button for food types (steamed bread, cream cake, and instant noodle), prompting to put in the food to be measured, closing the hatch, and pressing the start measuring button. And (4) the instrument starts to detect the closing condition of the airtight door of the L container, if the airtight door closing sensor detects that the cabin door is closed, the next step is carried out, otherwise, an error is reported, and the airtight door is prompted to be closed.

2) All the electromagnetic valves are self-checked through built-in electromagnetic valve state sensors, all the electromagnetic butterflies are ensured to be closed, whether the environment temperature is higher than 0 ℃ or higher than 45 ℃ or not is detected, and when the environment temperature is lower than 0 ℃, the alarm is not in a proper working temperature range. Detecting the content of octafluorocyclobutane in the L container, if the content is less than 0.01%, carrying out the next step, otherwise, reporting an error, and prompting to open the cabin door and ventilate.

3) Again prompting confirmation that the airtight door has been locked. After confirmation, the food mass is first weighed and is designated as M. After the vacuum pump valve is opened, the two-stage vacuum pump is started to carry out the vacuum pumping operation of the S container, and when the air pressure sensor of the S container detects that the vacuum degree reaches 2 multiplied by 10^-1And when Pa, closing the vacuum pump, closing a vacuum pump valve, and carrying out the next step.

4) And (3) opening the electromagnetic flow valve, starting the constant-temperature vaporizer to work, keeping the outlet temperature of the constant-temperature vaporizer connected with the S container slightly lower than the temperature of the L container, and keeping the maximum temperature difference not more than 10 ℃.

5) And when the S container air pressure sensor detects that the air pressure value of the S container is equal to 90% -98% of the air pressure of the L container, closing the electromagnetic flow valve. Delaying for 60S-120S, detecting the difference between the temperature of the S detection container and the temperature of the L container, and adjusting the temperature of the S container through a temperature compensation adjusting device. When the temperature difference is less than +/-0.05 ℃, detecting the difference between the detection air pressure of the S container and the detection air pressure of the L container again, controlling the temperature of the outlet air of the constant-temperature vaporizer to be equal to the temperature of the L container, gradually supplementing air until the air pressure of the S, L container is consistent, and closing the electromagnetic flow valve.

6) And opening the double-chamber electromagnetic butterfly valve, delaying for 2 seconds, then taking the values of the air pressure sensors in the S container and the L container, respectively comparing the values with the values before the electromagnetic butterfly valve is opened, and when the air pressure fluctuation is more than 0.2%. And reporting an error and simultaneously prompting that the air pressure sensor is damaged. The next step was carried out when the air pressure fluctuation was less than 0.2%.

7) The miniature convection fan is started, the miniature convection fan adopts a constant rotating speed, and the speed of the miniature convection fan is as follows: the air speed of food such as steamed bread, cookies, cream cake, etc. is controlled at 0.8-1.2m/s, and the circulating air quantity is 10 times V_SAnd is less than 15s, then the micro convection fan is powered off; special food: the air speed of the instant noodles is controlled to be 3-3.5m/s, and the circulating air quantity is more than 30 times V_SAnd is less than 25s, then the micro convection fan is powered off; proceed to the next step.

8) And (4) after delaying for 5s, entering a measuring stage, starting a high-precision octafluorocyclobutane NDIR sensor to measure the volume concentration of octafluorocyclobutane, recording the volume concentration as N%, and performing the next calculation.

9) The total volume sum V of the S container, the pipeline communicated with the S container and the valve when the butterfly valve stored in the adjusting system is closed_STotal volume sum V of L container and valve for communicating L container_LThe total volume is calibrated by using liquid before leaving the factory, and the numerical value is stored in the singlechip. k is a compensation coefficient, foods with skins such as complete steamed buns, sugar bags and the like are 1, other food coefficients have fluctuation of +/-0.5% in a micro gas exchange coefficient in unit time according to different types, the coefficients are determined by counting the same food test for multiple times, the coefficients are calculated by adopting a Lagrange interpolation method, a manufacturer can continuously upgrade a refinement coefficient library, and the compensation coefficient is not adopted for scenes with the measurement result accuracy requirement of more than 1 level.

11) Outputting the specific volume P of the food on a screen_FSimultaneously, the unlocking of the airtight door is prompted, and the lower part of the display screen is subjected to text prompting: please open the laboratory suction hood to suck the residual gas or open the window to ventilate.

Use notice: for the measurement of bread-type food, it is recommended to perform the overall measurement. If bread is required to be cut into pieces and sliced according to special requirements, so that the leakage cavities at the slicing positions are too much to influence the measurement accuracy, the components are uniformly sprayed on the surface of the food after being sampled, 0.1% -0.3% of pullulan solution is placed still for 1.5-3 hours, and then the measurement is carried out so as to improve the accuracy.

Claims

1. A food specific volume measuring instrument is characterized by comprising a rectangular box body (1), a food placing opening (2) is formed in the front side face of the box body (1), a gas-tight door (3) is arranged on the food placing opening (2), an S container and an L container are arranged in the box body (1), the S container is positioned above the L container, the volume of the S container is one fourth of that of the L container, the L container is communicated with the S container, two electromagnetic butterfly valves (406) are arranged at the communicated positions, a gas cylinder (8) is arranged on one side outside the L container and the S container, octafluoro cyclobutane with 99.999% purity is filled in the gas cylinder (8) and is used as standard gas, the gas cylinder (8) is communicated with the S container, a pressure reducing valve (801), an electromagnetic flow valve (802) and a constant temperature vaporizer (803) are arranged on a communicated pipeline, a vacuum pump (6) is arranged on the other side outside the L container and the, be equipped with vacuum pump valve (602) on metal guide pipe (601), metal pipeline and valve department are provided with the heat preservation, and the L container is equipped with volume micromatic setting (7), and the S container is equipped with volume micromatic setting (9), and L container and S container still are equipped with insulation construction, state calibration sensor respectively, and the L container is provided with food weight sensor, NDIR sensor, and the S container is provided with temperature compensation adjusting device.

2. The food specific volume measuring instrument according to claim 1, wherein the outer wall of the S container is provided with an S container temperature compensation and adjustment device (504) for controllably adjusting the gas temperature in the S container, the S container temperature compensation and adjustment device (504) is coated by an S container insulating layer (501) to form an S container insulating structure, and the calibration sensor for the internal state of the S container comprises an S container temperature sensor (502) and an S container air pressure detection sensor (503).

3. The food specific volume measuring instrument according to claim 1, wherein the L container is provided with a food placing opening (2), the heat preservation structure of the L container is formed by an L container heat preservation layer (408) covered by the outer surface, the calibration sensor for the state in the L container comprises an L container air pressure detection sensor (401) and an L container temperature detection sensor (402), a food weight sensor (405) arranged in the L container is suspended on a food placing basket (404), the food placing basket (404) is provided with a unique number corresponding to the instrument and is used for placing the measured food, the NDIR sensor is a high-precision octafluorocyclobutane NDIR sensor (403), the sensing end of the octafluorocyclobutane NDIR sensor is positioned in the L container, and the volume concentration of the output gas is measured by a non-dispersive infrared technology.

4. The apparatus for measuring the specific volume of food according to claim 1, wherein the electromagnetic butterfly valves (406) between the L container and the S container are divided into two groups, a miniature convection fan (409) is arranged at the air inlet and outlet positions of one group of the electromagnetic butterfly valves (406), an air flow deflection plate (407) is arranged at the air inlet and outlet positions of the other group of the electromagnetic butterfly valves (406), the valve clack inside the electromagnetic butterfly valves (406) rotates around the valve shaft to open and close, the valve shaft is sealed with the outside, and corresponding heat insulation structures are arranged outside the electromagnetic butterfly valves.

5. The food specific volume measuring instrument according to claim 1, wherein the volume fine-tuning device (7) comprises a cylindrical adjusting column (701) and a threaded telescopic rod (702) at the rear part of the adjusting column, the cylindrical adjusting column (701) extends into the L container or the S container, the threaded telescopic rod (702) rotates to drive the cylindrical adjusting column (701) to extend into or out of the L container or the S container, and the adjusting column is provided with a damping ring (703) and a sealing ring (704) to realize sealing.

6. The food specific volume measuring instrument according to claim 1, characterized in that the front side of the box body (1) is further provided with a gas cylinder cabin door (101), a display screen (102), a working state indicator lamp (103) and a control button (104), the upper side of the box body (1) is provided with a handle (105), the oblique side is provided with a foot pad (106), the airtight door (3) is provided with a transparent observation window (107), and the inside of the box body (1) is provided with a control circuit.

7. The food specific volume measuring instrument according to claim 6, wherein one side of the airtight door (3) is provided with a hinge (108) to be connected with the box body (1), and the rest edge of the airtight door (3) is provided with a plurality of rotary locking buckles (109) to tightly seal the airtight door (3) on the food placing opening (2) of the box body (1).

8. The food specific volume measuring instrument according to claim 6, wherein the control circuit comprises a single chip microcomputer control module inside the box body (1), a control button (104), an L container air pressure detection sensor (401), an L container temperature detection sensor (402), an S container temperature sensor (502), an S container air pressure detection sensor, a food weight sensor (405), an octafluoro cyclobutane NDIR sensor (403) are connected to the input end of the single chip microcomputer control module through lines, and a display screen (102), a vacuum pump (6), a vacuum pump valve (602), an electromagnetic butterfly valve (406), a micro convection fan, an S container temperature compensation and adjustment device (504), an electromagnetic flow valve (802), a constant temperature vaporizer (803) and a working state indicator lamp (103) are connected to the driving output end of the single chip microcomputer control module through wires.

9. A method for measuring specific volume by using the specific volume measuring instrument for food according to any one of claims 1 to 9, comprising the steps of,