CN111896172A

CN111896172A - Method for calibrating pressure by using handheld infrared equipment

Info

Publication number: CN111896172A
Application number: CN202010637136.9A
Authority: CN
Inventors: 蒋忠亮; 许志峰
Original assignee: Xian Modern Chemistry Research Institute
Current assignee: Xian Modern Chemistry Research Institute
Priority date: 2020-07-03
Filing date: 2020-07-03
Publication date: 2020-11-06
Anticipated expiration: 2040-07-03
Also published as: CN111896172B

Abstract

The invention discloses a method for calibrating pressure by using handheld infrared equipment, which comprises the steps of clockwise rotating and screwing a vacuum-pumping switch (4) until a fourth upper end circular plane of the vacuum-pumping switch (4) is flush with a second lower end upward concentric circular ring surface of a vacuum-pumping inner cavity (2); the invention can accurately control the volume of the sucked or squeezed gas, thereby accurately controlling the pressure of the gas in the closed space. Compared with the original scheme, the method reduces the error of the gas pressure value, more accurately calibrates the parameters of the internal stress release device, and more reliably obtains data. Therefore, when the internal stress releasing device is used on the thin-wall shell, the effect can be exerted more reliably.

Description

Method for calibrating pressure by using handheld infrared equipment

Technical Field

The invention belongs to the technical field of calibration, relates to a method for calibrating pressure, and particularly relates to a method for calibrating pressure by using handheld infrared equipment.

Background

The liquid-phase fire extinguishing agent is filled in the fire extinguishing bomb, and is scattered into the air through the scattering mechanism, so that wide-range fire extinguishing agent cloud mist is formed, and burning flames are extinguished. In order not to affect the spreading range of the liquid-phase fire extinguishing agent, the shell of the fire extinguishing bomb is usually of a thin-wall structure, and therefore, the fire extinguishing bomb is of a typical thin-wall shell structure filled with liquid-phase materials.

For a thin-wall shell structure filled with liquid-phase materials, the expansion coefficient of the liquid materials is much higher than that of solid materials, the liquid materials are incompressible materials, the internal stress of the shell caused by the expansion of the liquid-phase materials is very high after the temperature rises, and the shell is damaged at a weak position due to overhigh internal stress, so that the leakage of the liquid-phase materials is caused, and major accidents are caused. The patent "an internal stress release device for liquid-phase loading warhead" (china, 6 months 2015, application number: 201510304454.2) discloses an internal stress release device (hereinafter referred to as internal stress release device) suitable for filling a liquid-phase material thin-wall shell structure, when the internal stress of the liquid-phase material thin-wall shell structure (hereinafter referred to as thin-wall shell) is too large due to expansion of a liquid-phase material, an annular disc spring of the device is subjected to compression deformation, the space occupied by the liquid-phase material is increased, the expansion stress of the liquid-phase material is relieved, and the internal stress of the thin-wall shell is reduced; when the temperature is reduced and the liquid phase material shrinks to cause overlarge negative pressure in the thin-wall shell, the annular disc spring of the device generates tensile deformation, so that the space occupied by the liquid phase material is reduced, and the shrinkage stress of the liquid phase material is relieved, thereby reducing the internal stress of the thin-wall shell and solving the problem of the damage of the thin-wall shell caused by overlarge internal stress caused by the expansion with heat and contraction with cold of the liquid phase material.

The internal stress release devices have various specifications from small to large in size, each internal stress release device needs performance detection and calibration, the adjustable volume of each internal stress release device under different internal stresses is researched, and the internal stress release devices are calibrated after the parameters are detected. Then, according to the requirements of the thin-wall shell in the actual use process, namely according to the environment temperature of the thin-wall shell in the actual use process, the volume of the liquid-phase material for expansion and contraction and the corresponding internal stress are obtained, and then an internal stress release device matched with the actual requirements is installed in the thin-wall shell, so that the safety and the reliability of the thin-wall shell in the actual use process can be ensured, and the redundant design can be avoided.

Regarding the performance detection and calibration of the internal stress release device, if a real state experiment is carried out, the internal stress release device is installed in a thin-wall shell, a liquid-phase material is filled in the thin-wall shell, the temperature is changed, the internal stress data of the liquid-phase material is obtained, then the volume adjustment amount of the internal stress release device in the internal stress environment is measured, and the performance parameters of the internal stress release device are calibrated. The scientific research method is to adopt simulation experiment research, install the internal stress release device in the enclosed space, add high-pressure gas or vacuumize in the enclosed space, make the internal pressure value close to the real state of the thin-walled shell inside, investigate the adjustable volume of the internal stress release device under the effect of internal pressure, thus obtain the performance parameter of the internal stress release device. Vacuumizing and pressurizing are needed in a closed space of a simulation experiment so as to achieve the purpose of changing the internal gas pressure. Usually, the evacuation is performed by a vacuum pump, and the pressurization is performed by an air compressor. However, the vacuum pump and the air compressor have an advantage in changing the speed of the gas pressure, and cannot be precisely controlled in changing the volume of the gas, and at the same temperature, the pressure of the gas is uniquely determined by the volume, and the gas pressure cannot be precisely controlled due to the inaccuracy of the gas volume, so that the specific value of the internal gas pressure cannot be precisely controlled by the vacuum pump and the air compressor. Inside gas pressure value generally acquires through the manometer reading, and gas is at the enclosure space in-process that flows, and gas pressure value is different everywhere, and from inside to oral area gas pressure be certain gradient, and the manometer reading can only represent the pressure value of manometer position this moment, and can not represent inside average pressure value, along with inside pressure gradient recovery balance, the numerical value of manometer also can the corresponding change. Therefore, the error of controlling the internal pressure of the closed space through the vacuum pump and the air compressor is large, the performance of the internal stress release device is calibrated, and the most critical parameter is the pressure value. If the pressure value is inaccurate, the calibration error is too large, and the actual use effect of the product is influenced.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention provides a method for calibrating pressure by using a handheld infrared device, which can accurately control the volume of sucked or squeezed gas and further can accurately control the pressure of the gas in a closed space. Compared with the original scheme, the method reduces the error of the gas pressure value, more accurately calibrates the parameters of the internal stress release device, and more reliably obtains data. Therefore, when the internal stress releasing device is used on the thin-wall shell, the effect can be exerted more reliably.

The invention provides a method for calibrating pressure by using handheld infrared equipment, which comprises a vacuum-pumping hose 3 and a pressure gauge 5, and is characterized by also comprising a power piston 1, a vacuum-pumping inner cavity 2, a vacuum-pumping switch 4 and an exhaust switch 6;

the power piston 1 is a first cylinder, the first cylinder of the power piston 1 is a revolving body, the lower surface of the first cylinder of the power piston 1 is a first lower end circular plane, the side surface of the first cylinder of the power piston 1 is a first outer cylindrical surface, the upper surface of the first cylinder of the power piston 1 is a first upper end circular plane, the center of the first upper end circular plane of the power piston 1 is provided with a first cylindrical boss, the axis of the revolving body of the first cylindrical boss of the power piston 1 is superposed with the axis of the revolving body of the first cylinder of the power piston 1, and the side surface of the first cylindrical boss of the power piston 1 is provided with a first external thread;

the axis of the revolving body of the power piston 1 is vertical to the ground;

the vacuumizing inner cavity 2 is a second cylinder body, the second cylinder body of the vacuumizing inner cavity 2 is a revolving body, the inner side surface of the second cylinder body of the vacuumizing inner cavity 2 is a second inner cylindrical surface, the upper end of the second inner cylindrical surface of the vacuumizing inner cavity 2 is provided with a second upper end inner flange, the inner side surface of the second upper end inner flange of the vacuumizing inner cavity 2 is provided with a second upper end internal thread, the lower end surface of the second upper end inner flange of the vacuumizing inner cavity 2 is a second upper end downward concentric circular ring surface, the lower end of the second inner cylindrical surface of the vacuumizing inner cavity 2 is provided with a second lower end inner flange, the upper end surface of the second lower end inner flange of the vacuumizing inner cavity 2 is a second lower end upward concentric circular ring surface, the lower end surface of the second lower end inner flange of the vacuumizing inner cavity 2 is a second lower end downward concentric circular ring surface, the inner side surface of the second lower end inner flange of the vacuumizing inner cavity 2 is a second lower end inner cylindrical surface, the second lower end of the second, the middle part of the inner cylindrical surface of the second lower end of the vacuumizing inner cavity 2 is provided with a second annular groove, the left end of the lower surface of the second annular groove of the vacuumizing inner cavity 2 is provided with a second left-end circular through hole, the axis of the second left-end circular through hole of the vacuumizing inner cavity 2 is parallel to the axis of the revolution body of the vacuumizing inner cavity 2, the second left-end circular through hole of the vacuumizing inner cavity 2 is communicated with the second annular groove of the vacuumizing inner cavity 2 and the lower part of the second lower end downward concentric circular ring surface of the vacuumizing inner cavity 2, the right end of the lower surface of the second annular groove of the vacuumizing inner cavity 2 is provided with a second right-end circular through hole, the axis of the second right-end circular through hole of the vacuumizing inner cavity 2 is parallel to the axis of the revolution body of the vacuumizing inner cavity 2, the second circular through hole of the second right-end of the vacuumizing inner cavity 2 is communicated with the lower part of the second lower end downward concentric circular ring surface of the vacuumizing inner, the second right end of the vacuumizing inner cavity 2 is parallel to the axis of the revolving body of the vacuumizing inner cavity 2 along the axis of the circular through hole, the second right end of the vacuumizing inner cavity 2 is communicated with the upper part of the upward concentric circular ring surface of the second lower end of the vacuumizing inner cavity 2 and the lower part of the downward concentric circular ring surface of the second lower end of the vacuumizing inner cavity 2 along the circular through hole, the inner side surface of the second right end of the vacuumizing inner cavity 2 along the circular through hole is a second right end inner circular cylindrical surface, and the lower end of the second right end inner circular cylindrical surface of the vacuumizing inner cavity 2 is provided with a;

the axis of a revolving body of the vacuumizing inner cavity 2 coincides with the axis of a revolving body of the power piston 1, a first cylinder of the power piston 1 is positioned inside a second cylinder of the vacuumizing inner cavity 2, a first upper end circular plane of the power piston 1 is positioned at the lower end of a downward concentric circular ring surface at the second upper end of the vacuumizing inner cavity 2, a first lower end circular plane of the power piston 1 is positioned at the upper end of an upward concentric circular ring surface at the second lower end of the vacuumizing inner cavity 2, a first external thread of the power piston 1 is matched with an internal thread at the second upper end of the vacuumizing inner cavity 2, and a first external cylindrical surface of the power piston 1 is in sliding fit contact with a second internal cylindrical surface of the vacuumizing inner cavity 2;

the vacuumizing hose 3 is a third round pipe, and the third round pipe of the vacuumizing hose 3 is a revolving body;

the vacuum-pumping hose 3 is positioned at the lower end of the vacuum-pumping inner cavity 2, the right end of a third circular pipe of the vacuum-pumping hose 3 is connected with a second left-end circular through hole of the vacuum-pumping inner cavity 2, and the left end of the third circular pipe of the vacuum-pumping hose 3 is connected with a closed space in which gas pressure needs to be changed;

the vacuumizing switch 4 is a fourth cylinder, the fourth cylinder of the vacuumizing switch 4 is a revolving body, the upper surface of the fourth cylinder of the vacuumizing switch 4 is a fourth upper end circular plane, the side surface of the fourth cylinder of the vacuumizing switch 4 is a fourth outer cylindrical surface, and the lower end of the fourth outer cylindrical surface of the vacuumizing switch 4 is provided with a fourth outer thread;

the axis of the revolving body of the vacuum switch 4 coincides with the axis of the revolving body of the power piston 1, the fourth outer cylindrical surface of the vacuum switch 4 is in sliding fit contact with the inner cylindrical surface of the second lower end of the vacuum cavity 2, the fourth outer thread of the vacuum switch 4 is in internal thread fit with the second lower end of the vacuum cavity 2, and the fourth upper end circular plane of the vacuum switch 4 is flush with the upward concentric circular ring surface of the second lower end of the vacuum cavity 2;

the pressure gauge 5 is used for detecting the pressure of gas, the upper end of the pressure gauge 5 is provided with a fifth outer cylindrical surface, the lower end of the pressure gauge 5 is provided with a fifth dial plate, and the fifth dial plate of the pressure gauge 5 displays the pressure value of the detected gas;

a fifth outer cylindrical surface of the pressure gauge 5 is connected with a second right-end circular through hole of the vacuumizing inner cavity 2, the pressure gauge 5 is communicated with a second annular groove of the vacuumizing inner cavity 2, and the pressure gauge 5 detects and displays a gas pressure value in the second annular groove of the vacuumizing inner cavity 2;

the exhaust switch 6 is a sixth cylinder, the sixth cylinder of the exhaust switch 6 is a revolving body, the upper surface of the sixth cylinder of the exhaust switch 6 is a sixth upper end circular plane, the side surface of the sixth cylinder of the exhaust switch 6 is a sixth outer cylindrical surface, and the lower end of the sixth outer cylindrical surface of the exhaust switch 6 is provided with a sixth external thread;

the axis of a revolving body of the exhaust switch 6 is parallel to the axis of a revolving body of the power piston 1, the sixth outer cylindrical surface of the exhaust switch 6 is in sliding fit contact with the inner cylindrical surface of the second right end of the vacuumizing inner cavity 2, the sixth outer thread of the exhaust switch 6 is in inner thread fit with the second right end of the vacuumizing inner cavity 2, and the sixth upper end circular plane of the exhaust switch 6 is flush with the upward concentric circular ring surface of the second lower end of the vacuumizing inner cavity 2.

The ratio of the diameter of the first cylindrical boss of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1 is 1: 3-4;

the ratio of the axial length of the first outer cylindrical surface of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1 is 1: 5-6;

a handheld infrared tester is arranged outside the device, the handheld infrared tester is used for testing the gas pressure inside the vacuumizing inner cavity 2, pressure data are obtained in a digital display mode, and the data are only used as the reference of the method;

the method for calibrating the pressure by utilizing the handheld infrared device comprises the following steps:

step 1: placing the vacuumizing inner cavity 2 on a horizontal table;

step 2: assembling a power piston 1 with a vacuumizing inner cavity 2;

and step 3: assembling a vacuum-pumping hose 3 with a vacuum-pumping inner cavity 2;

and 4, step 4: assembling a vacuumizing switch 4 with a vacuumizing inner cavity 2;

and 5: assembling a pressure gauge 5 with the vacuumizing inner cavity 2;

step 6: assembling an exhaust switch 6 with the vacuumizing inner cavity 2;

and 7: when the gas pressure of the closed space needs to be reduced: rotating and screwing the vacuum switch 4 clockwise until a fourth upper end circular plane of the vacuum switch 4 is flush with a second lower end upward concentric circular ring surface of the vacuum cavity 2; the exhaust switch 6 rotates anticlockwise until being dismounted; the power piston 1 rotates clockwise to the lowest position until the first lower end circular plane of the power piston 1 contacts with the second lower end upward concentric circular ring surface of the vacuum pumping inner cavity 2; then the exhaust switch 6 is rotated clockwise and screwed until the sixth upper end circular plane of the exhaust switch 6 is flush with the second lower end upward concentric circular ring surface of the vacuum-pumping inner cavity 2; the vacuumizing switch 4 rotates anticlockwise and is loosened until a fourth upper end circular plane of the vacuumizing switch 4 is flush with the lower surface of a second annular groove of the vacuumizing inner cavity 2; then the power piston 1 is rotated anticlockwise to the uppermost position until the first upper end circular plane of the power piston 1 is contacted with the downward concentric circular ring surface of the second upper end of the vacuum-pumping inner cavity 2; thus, the closed space is exhausted once, so that the gas pressure of the closed space is reduced;

and 8: repeating the step 7, gradually pumping the closed space to gradually reduce the gas pressure of the closed space, waiting for 3-5 minutes after the step 7 is completed each time, and then performing the next step 7 until the gas pressure of the closed space reaches a preset value, wherein the gas pressure value of the closed space is P, and the value of P is as follows:

p is the gas pressure value of the closed space, unit: pa; v is the enclosed space volume, unit: l; c is the volume of the inner cavity of the device, unit: l; t is the air pressure value in units: pa; n is the number of times of pumping the closed space by the device; a is an empirical coefficient, and the value range of a is 0.85-0.91;

and step 9: when it is desired to increase the gas pressure in the enclosed space: rotating and screwing the vacuum switch 4 clockwise until a fourth upper end circular plane of the vacuum switch 4 is flush with a second lower end upward concentric circular ring surface of the vacuum cavity 2; the exhaust switch 6 rotates anticlockwise until being dismounted; rotating the power piston 1 to the uppermost position anticlockwise until a first upper end circular plane of the power piston 1 is contacted with a second upper end downward concentric circular ring surface of the vacuumizing inner cavity 2; then the exhaust switch 6 is rotated clockwise and screwed until the sixth upper end circular plane of the exhaust switch 6 is flush with the second lower end upward concentric circular ring surface of the vacuum-pumping inner cavity 2; the vacuumizing switch 4 rotates anticlockwise and is loosened until a fourth upper end circular plane of the vacuumizing switch 4 is flush with the lower surface of a second annular groove of the vacuumizing inner cavity 2; then the power piston 1 is rotated clockwise to the lowest position until the first lower end circular plane of the power piston 1 contacts with the second lower end upward concentric circular ring surface of the vacuum-pumping inner cavity 2; thus, the gas filling of the closed space is completed once, so that the gas pressure of the closed space is increased;

step 10: and (3) repeating the step (9), gradually filling gas into the closed space, so that the gas pressure of the closed space is gradually increased, waiting for 3-5 minutes after the step (9) is completed each time, and then performing the next step (9) until the gas pressure of the closed space reaches a preset value, wherein the gas pressure value of the closed space is Q, and the value of Q is as follows:

q is the closed space gas pressure value, unit: pa; v is the enclosed space volume, unit: l; c is the volume of the inner cavity of the device, unit: l; m is the air-entrapping frequency of the closed space through the device; b is an empirical coefficient, and the value range of b is 0.81-0.86.

With respect to the ratio of the first cylindrical boss diameter of power piston 1 to the first outer cylindrical surface diameter of power piston 1, and the ratio of the first outer cylindrical surface axial length of power piston 1 to the first outer cylindrical surface diameter of power piston 1, any of the following 2 ways may be adopted:

implementation mode 1: the ratio of the diameter of the first cylindrical boss of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1 is 1: 3;

the ratio of the axial length of the first outer cylindrical surface of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1 is 1: 5.

implementation mode 2: the ratio of the diameter of the first cylindrical boss of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1 is 1: 4;

the ratio of the axial length of the first outer cylindrical surface of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1 is 1: 6.

the method for calibrating the pressure by using the handheld infrared equipment has the following technical effects:

the invention can accurately control the volume of the sucked or squeezed gas in relation to the change of the gas pressure in the closed space, and thus can accurately control the gas pressure inside the closed space. Compared with the original scheme, the method reduces the error of the gas pressure value, more accurately calibrates the parameters of the internal stress release device, and more reliably obtains data. Therefore, when the internal stress releasing device is used on the thin-wall shell, the effect can be exerted more reliably.

Drawings

Fig. 1 is a schematic diagram of a method for calibrating pressure using a hand-held infrared device. 1. The device comprises a power piston, 2, a vacuumizing inner cavity, 3, a vacuumizing hose, 4, a vacuumizing switch, 5, a pressure gauge, 6 and an exhaust switch.

Detailed Description

The present invention is further described in detail with reference to the drawings and examples, it should be noted that the present invention is not limited to the following examples, and equivalent changes based on the technical scheme of the present invention are within the scope of the present invention.

Example 1:

as shown in fig. 1, the present embodiment provides a method for calibrating pressure by using a handheld infrared device, which includes a vacuum hose 3 and a pressure gauge 5, and is characterized by further including a power piston 1, a vacuum cavity 2, a vacuum switch 4, and an exhaust switch 6;

the axis of the revolving body of the power piston 1 is vertical to the ground;

Regarding the ratio of the first cylindrical land diameter of power piston 1 to the first outer cylindrical surface diameter of power piston 1, several factors are mainly considered: stiffness, strength, driving force.

When the ratio of the diameter of the first cylindrical boss of the power piston 1 to the diameter of the first outer cylindrical surface of the power piston 1 is too large, the mass of the power piston 1 is too large, the power piston 1 needs to be rotated when the closed space is vacuumized or pressurized by the invention, and if the mass of the power piston 1 is too large, the stiffness is too large, and power resources are wasted.

When the ratio of the diameter of the first cylindrical boss of the power piston 1 to the diameter of the first outer cylindrical surface of the power piston 1 is too small, the diameter of the first cylindrical boss of the power piston 1 is too small, when the closed space is vacuumized or pressurized by the vacuum pump, the first cylindrical boss of the power piston 1 needs to be rotated, the strength of the first cylindrical boss of the power piston 1 is insufficient due to the fact that the diameter of the first cylindrical boss is too small, and once the first cylindrical boss of the power piston 1 is broken, the system is damaged.

When the invention is used for vacuumizing or pressurizing the closed space, the first cylindrical boss of the power piston 1 is rotated, the power piston 1 moves downwards or upwards, the driving force for rotating the power piston 1 is related to the thread pitch of the first external thread of the power piston 1, the smaller the thread pitch of the first external thread of the power piston 1 is, the smaller the advancing distance of the power piston 1 is per rotation, the larger the power is, the larger the thread pitch of the first external thread of the power piston 1 is, the larger the advancing distance of the power piston 1 is per rotation, the smaller the power is, and when the air pressure value for vacuumizing or pressurizing a closed space is considered to be larger, in order not to make the torque for rotating the power piston 1 too large, which is difficult to operate practically, the pitch is usually chosen smaller, if the thread pitch is 1.5 to 2mm, the diameter of the first cylindrical boss of the power piston 1 is matched with the thread pitch.

It has been found through extensive experimentation that the ratio of the first cylindrical land diameter of power piston 1 to the first outer cylindrical surface diameter of power piston 1 is 1: 3-4 hours, the mass of the power piston 1 is not too large, the stiffness is not too large, and the waste of power resources is avoided. The diameter of the first cylindrical boss of the power piston 1 cannot be too small, the strength of the first cylindrical boss is insufficient enough, and the safety of the system is guaranteed. The pitch of the first external thread of the power piston 1 can be 1.5-2 mm. The stiffness, strength and driving force requirements of the power piston 1 are met.

Thus, the ratio of the first cylindrical land diameter of power piston 1 to the first outer cylindrical surface diameter of power piston 1 is 1: 3-4;

in this embodiment, the ratio of the diameter of the first cylindrical boss of the power piston 1 to the diameter of the first outer cylindrical surface of the power piston 1 is 1: 3.

regarding the ratio of the axial length of the first outer cylindrical surface of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1, the following aspects are mainly considered: the strength of the power piston 1, the volume of the inner cavity of the device, the motion smoothness of the power piston 1 and the relative tightness of the power piston 1 and the vacuumizing inner cavity 2.

Selecting the ratio of the axial length of the first outer cylindrical surface of the power piston 1 to the diameter of the first outer cylindrical surface of the power piston 1 in the following intervals, 1: 1-2 and 1: 2-3, 1: 3-4, 1: 4-5, 1: 5-6, 1: 6-7, 1: 7 to 8. And respectively carrying out experiments, examining the performances of the aspects, and grading, wherein the grading standards are as follows.

Regarding the strength of the power piston 1, a pressure difference exists between the lower end and the upper end of the power piston 1, the pressure acts on the first lower end circular plane of the power piston 1, when the axial length of the first outer cylindrical surface of the power piston 1 is too small, the power piston 1 can be damaged due to insufficient strength, and only when the axial length of the first outer cylindrical surface of the power piston 1 is large enough, the strength of the power piston 1 is sufficient, so that the integrity of the power piston 1 can be ensured. The strength score of the power piston 1 was divided into the following 2 criteria:

sufficient strength, no failure: 10 minutes;

insufficient strength, failure occurred: -10 minutes.

Regarding the volume of the inner cavity of the device, the difference of the volume of the inner cavity of the device of the invention between the upward movement limit position and the downward movement limit position of the power piston 1 is the volume which can be adjusted in each work of the invention, if the volume which is adjusted in each work is small, the required air pressure can be reached only by carrying out a plurality of works, the time is wasted, and when the volume which is adjusted in each work is large, the working times can be reduced, the required air pressure can be reached, and the time is saved. The larger the axial length of the first outer cylindrical surface of the power piston 1 is, the smaller the volume of the inner cavity of the device is, the smaller the volume regulated each time is, and the longer the working time is. The smaller the axial length of the first outer cylindrical surface of the power piston 1 is, the larger the volume of the inner cavity of the device is, the larger the volume of each adjustment is, and the shorter the working time is. The volume of the inner cavity of the device is divided into the following 4 standards:

the volume of the inner cavity of the device is less than 30% of the external volume: 0 minute;

the volume of the inner cavity of the device is 30-50% of the external volume: 2 min;

the volume of the inner cavity of the device is 50-80% of the external volume: 4, dividing;

the volume of the inner cavity of the device exceeds 80% of the external volume: 8 minutes.

Regarding the motion smoothness of the power piston 1, when the power piston 1 moves axially, the axis of the power piston 1 is inclined due to the asymmetry of the rotating force, and when the axial length of the first outer cylindrical surface of the power piston 1 is large enough, the axis of the inclined power piston 1 is corrected due to the contact force between the first outer cylindrical surface of the power piston 1 and the second inner cylindrical surface of the vacuum-pumping cavity 2, and finally the axes of the power piston 1 and the vacuum-pumping cavity 2 are overlapped. When the axial length of the first outer cylindrical surface of the power piston 1 is small, the inclined power piston 1 is jammed, so that the rotation torque is further increased, and the system is damaged. The motion smoothness of the power piston 1 is divided into the following 2 standards:

the power piston 1 moves smoothly without jamming: 10 minutes;

the power piston 1 has unsmooth movement, and jamming occurs: -10 minutes.

Regarding the relative leakproofness of power piston 1 and evacuation inner chamber 2, when the axial length of the first outer cylinder face of power piston 1 was big enough, the first outer cylinder face of power piston 1 was big enough with the second inner cylinder face contact surface of evacuation inner chamber 2, and the sealing washer on the first outer cylinder face of power piston 1 can be with the better laminating of the second inner cylinder face of evacuation inner chamber 2, realizes sealedly. When the axial length of the first outer cylindrical surface of the power piston 1 is too small, the contact surface of the first outer cylindrical surface of the power piston 1 and the second inner cylindrical surface of the vacuumizing inner cavity 2 is too small, and when the rotating force is asymmetric and the sealing ring on the first outer cylindrical surface of the power piston 1 inclines, the sealing ring is separated from the second inner cylindrical surface of the vacuumizing inner cavity 2, so that leakage is caused. The relative tightness of the power piston 1 and the vacuum cavity 2 is divided into the following 2 standards:

the power piston 1 and the vacuum pumping inner cavity 2 are good in sealing performance and do not leak: 10 minutes;

the power piston 1 and the vacuum pumping inner cavity 2 have poor sealing performance and leak: -10 minutes.

The values of the ratio of the axial length of the first outer cylindrical surface of the power piston 1 to the diameter of the first outer cylindrical surface of the power piston 1 are taken according to the intervals, experiments are carried out, scoring is carried out according to the scoring standards, and the obtained scores are as follows:

it has been found through experimentation that when the ratio of the axial length of the first outer cylindrical surface of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1 is 1: and when the score is 5-6, obtaining the highest score, and obtaining 36 scores.

Thus, the ratio of the first outer cylindrical surface axial length of power piston 1 to the first outer cylindrical surface diameter of power piston 1 is 1: 5 to 6.

In this embodiment, the ratio of the axial length of the first outer cylindrical surface of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1 is 1: 5.

step 1: placing the vacuumizing inner cavity 2 on a horizontal table;

step 2: assembling a power piston 1 with a vacuumizing inner cavity 2;

and 5: assembling a pressure gauge 5 with the vacuumizing inner cavity 2;

step 6: assembling an exhaust switch 6 with the vacuumizing inner cavity 2;

and 8: and 7, repeating the step 7, gradually exhausting the closed space to gradually reduce the gas pressure of the closed space, and after the step 7 is finished each time, the pressure of the internal gas is not equal, so that pressure difference exists, convection motion can occur, and waiting for 3-5 minutes is realized. The regional balance of inside gas pressure, gas pressure is equal everywhere, moreover, at the in-process of bleeding, gas temperature can reduce, waits for 3 ~ 5 minutes after, and the temperature resumes the room temperature, carries out next step 7 again, and until enclosure gas pressure reaches the predetermined value, enclosure gas pressure value is P, and the value of P is according to following formula:

p is the gas pressure value of the closed space, unit: pa; v is the enclosed space volume, unit: l; c is the volume of the inner cavity of the device, unit: l; t is the air pressure value in units: pa; n is the number of times of pumping the closed space by the device; a is an empirical coefficient, and theoretically, the value of a is 1. In practical operation, however, the phenomenon that the gas volume is locally inaccurate exists in the process of turning on and off the vacuumizing switch 4 every time and turning on and off the exhaust switch 6 every time, a value range of a is found to be 0.85-0.91 through a large number of experiments, the value of the pressure gauge 5 can be referred to in the process of pumping air into the closed space, and the effect of the invention can be verified by the value of the pressure gauge 5;

step 10: and (4) repeating the step 9, gradually filling gas into the closed space, so that the gas pressure of the closed space is gradually increased, and after the step 9 is completed each time, the pressure of the internal gas is unequal, pressure difference exists, convection motion can occur, and the time is 3-5 minutes. The regional balance of inside gas pressure, gas pressure is equal everywhere, moreover, at the air entrainment in-process, gas temperature can improve, waits for 3 ~ 5 minutes after, the temperature resumes the room temperature, carries out next step 9 again, and until enclosure gas pressure reaches the predetermined value, enclosure gas pressure value is Q, and the value of Q is according to following formula:

q is the closed space gas pressure value, unit: pa; v is the enclosed space volume, unit: l; c is the volume of the inner cavity of the device, unit: l; m is the air-entrapping frequency of the closed space through the device; b is an empirical coefficient, and theoretically, the value of b is 1. In practical operation, however, the phenomenon that the gas volume is locally inaccurate exists in the process of turning on and off the vacuumizing switch 4 every time and turning on and off the exhaust switch 6 every time, and a large number of experiments show that the value range of b is 0.81-0.86, the value of the pressure gauge 5 can be referred to in the process of filling gas into a closed space, and the effect of the invention can be verified by the value of the pressure gauge 5.

Firstly, specifying a pressure value, respectively using a vacuum pump and an air compressor of the original scheme to vacuumize and pressurize a closed space twenty times, then using the invention to vacuumize and pressurize the closed space twenty times, measuring a specific pressure value after the vacuumization and the pressurizing are completed, summarizing error ranges of an actual pressure value and the specified pressure value, and obtaining an experimental result as follows:

specified pressure value, MPa	Error range of original scheme	Error range of the invention
			-0.1	±10％	±1％
0.1	±10％	±1％
			0.2	±10％	±1％
0.3	±10％	±1％
			0.5	±10％	±1％
0.7	±8％	±1％
			1	±8％	±1％

Analysis shows that the error range of the pressure value of the vacuumizing and pressurizing and the preset value is +/-8% - +/-10% through twenty experiments in the original scheme, the error range of the pressure value of the vacuumizing and pressurizing and the preset value is reduced to +/-1% through the method, the error of the pressure value of the closed space is greatly reduced, and the accuracy of the pressure value is improved.

The method for calibrating pressure by using the handheld infrared equipment can accurately control the volume of sucked or squeezed gas about changing the gas pressure in the closed space, and further can accurately control the gas pressure in the closed space. Compared with the original scheme, the method reduces the error of the gas pressure value, more accurately calibrates the parameters of the internal stress release device, and more reliably obtains data. Therefore, when the internal stress releasing device is used on the thin-wall shell, the effect can be exerted more reliably.

Example 2:

the axis of the revolving body of the power piston 1 is vertical to the ground;

in this embodiment, the ratio of the diameter of the first cylindrical boss of the power piston 1 to the diameter of the first outer cylindrical surface of the power piston 1 is 1: 4.

sufficient strength, no failure: 10 minutes;

insufficient strength, failure occurred: -10 minutes.

the power piston 1 moves smoothly without jamming: 10 minutes;

the power piston 1 has unsmooth movement, and jamming occurs: -10 minutes.

In this embodiment, the ratio of the axial length of the first outer cylindrical surface of power piston 1 to the diameter of the first outer cylindrical surface of power piston 1 is 1: 6.

step 1: placing the vacuumizing inner cavity 2 on a horizontal table;

step 2: assembling a power piston 1 with a vacuumizing inner cavity 2;

and 5: assembling a pressure gauge 5 with the vacuumizing inner cavity 2;

step 6: assembling an exhaust switch 6 with the vacuumizing inner cavity 2;

Claims

1. A method for calibrating pressure by using handheld infrared equipment comprises a vacuum-pumping hose (3) and a pressure gauge (5), and is characterized by further comprising a power piston (1), a vacuum-pumping inner cavity (2), a vacuum-pumping switch (4) and an exhaust switch (6);

the power piston (1) is a first cylinder, the first cylinder of the power piston (1) is a rotary body, the lower surface of the first cylinder of the power piston (1) is a first lower end circular plane, the side surface of the first cylinder of the power piston (1) is a first outer cylindrical surface, the upper surface of the first cylinder of the power piston (1) is a first upper end circular plane, a first cylindrical boss is arranged at the center of the first upper end circular plane of the power piston (1), the rotary body axis of the first cylindrical boss of the power piston (1) is superposed with the rotary body axis of the first cylinder of the power piston (1), and a first external thread is arranged on the side surface of the first cylindrical boss of the power piston (1);

the axis of the revolving body of the power piston (1) is vertical to the ground;

the vacuumizing inner cavity (2) is a second cylinder body, the second cylinder body of the vacuumizing inner cavity (2) is a revolving body, the inner side surface of the second cylinder body of the vacuumizing inner cavity (2) is a second inner cylindrical surface, the upper end of the second inner cylindrical surface of the vacuumizing inner cavity (2) is provided with a second upper end inner flange, the inner side surface of the second upper end inner flange of the vacuumizing inner cavity (2) is provided with a second upper end internal thread, the lower end surface of the second upper end inner flange of the vacuumizing inner cavity (2) is a second upper end downward concentric circular ring surface, the lower end surface of the second inner cylindrical surface of the vacuumizing inner cavity (2) is provided with a second lower end inner flange, the upper end surface of the second lower end inner flange of the vacuumizing inner cavity (2) is a second lower end upward concentric circular ring surface, the lower end surface of the second lower end inner flange of the vacuumizing inner cavity (2) is a second lower end downward concentric circular ring surface, the inner side surface of the second lower end inner flange of the vacuumizing inner cavity (, the lower end of the inner cylindrical surface of the second lower end of the vacuumizing inner cavity (2) is provided with a second lower end internal thread, the middle part of the inner cylindrical surface of the second lower end of the vacuumizing inner cavity (2) is provided with a second annular groove, the left end of the lower surface of the second annular groove of the vacuumizing inner cavity (2) is provided with a second left end circular through hole, the axis of the second left end circular through hole of the vacuumizing inner cavity (2) is parallel to the axis of the revolving body of the vacuumizing inner cavity (2), the second left end circular through hole of the vacuumizing inner cavity (2) is communicated with the second annular groove of the vacuumizing inner cavity (2) and the lower part of the downward concentric circular ring surface of the second lower end of the vacuumizing inner cavity (2), the right end of the lower surface of the second annular groove of the vacuumizing inner cavity (2) is provided with a second right end circular through hole, the axis of the second right end circular through hole of the vacuumizing inner cavity (2) is parallel to the axis of the revolving body of the vacuumizing inner cavity (2), and the lower part of a second lower end downward concentric circular ring surface of the inner cavity (2), the right end edge of the upward concentric circular ring surface of the second lower end of the vacuumizing inner cavity (2) is provided with a second right end edge circular through hole, the axis of the second right end edge circular through hole of the vacuumizing inner cavity (2) is parallel to the axis of the revolution body of the vacuumizing inner cavity (2), the second right end edge circular through hole of the vacuumizing inner cavity (2) is communicated with the upper part of the upward concentric circular ring surface of the second lower end of the vacuumizing inner cavity (2) and the lower part of the downward concentric circular ring surface of the second lower end of the vacuumizing inner cavity (2), the inner side surface of the second right end edge circular through hole of the vacuumizing inner cavity (2) is a second right end inner circular cylindrical surface, and the lower end of the second right end inner cylindrical surface;

the axis of a revolving body of the vacuumizing inner cavity (2) coincides with the axis of a revolving body of the power piston (1), a first cylinder of the power piston (1) is positioned inside a second cylinder of the vacuumizing inner cavity (2), a first upper end circular plane of the power piston (1) is positioned at the lower end of a downward concentric circular ring surface at the second upper end of the vacuumizing inner cavity (2), a first lower end circular plane of the power piston (1) is positioned at the upper end of an upward concentric circular ring surface at the second lower end of the vacuumizing inner cavity (2), a first external thread of the power piston (1) is matched with an internal thread at the second upper end of the vacuumizing inner cavity (2), and a first external cylindrical surface of the power piston (1) is in sliding fit contact with an internal cylindrical surface at the second inner end of the vacuumizing inner cavity (2);

the vacuum-pumping hose (3) is a third round pipe, and the third round pipe of the vacuum-pumping hose (3) is a revolving body;

the vacuum-pumping hose (3) is positioned at the lower end of the vacuum-pumping inner cavity (2), the right end of a third circular pipe of the vacuum-pumping hose (3) is connected with a second left-end circular through hole of the vacuum-pumping inner cavity (2), and the left end of the third circular pipe of the vacuum-pumping hose (3) is connected with a closed space of which the gas pressure needs to be changed;

the vacuumizing switch (4) is a fourth cylinder, the fourth cylinder of the vacuumizing switch (4) is a revolving body, the upper surface of the fourth cylinder of the vacuumizing switch (4) is a fourth upper end circular plane, the side surface of the fourth cylinder of the vacuumizing switch (4) is a fourth outer cylindrical surface, and the lower end of the fourth outer cylindrical surface of the vacuumizing switch (4) is provided with a fourth outer thread;

the axis of a revolving body of the vacuumizing switch (4) is superposed with the axis of a revolving body of the power piston (1), a fourth outer cylindrical surface of the vacuumizing switch (4) is in sliding fit contact with an inner cylindrical surface at the second lower end of the vacuumizing inner cavity (2), a fourth outer thread of the vacuumizing switch (4) is in internal thread fit with the second lower end of the vacuumizing inner cavity (2), and a fourth upper end circular plane of the vacuumizing switch (4) is flush with an upward concentric circular ring surface at the second lower end of the vacuumizing inner cavity (2);

the pressure gauge (5) is used for detecting the pressure of gas, the upper end of the pressure gauge (5) is provided with a fifth outer cylindrical surface, the lower end of the pressure gauge (5) is provided with a fifth dial plate, and the fifth dial plate of the pressure gauge (5) displays the pressure value of the detected gas;

a fifth outer cylindrical surface of the pressure gauge (5) is connected with a second right-end circular through hole of the vacuumizing inner cavity (2), the pressure gauge (5) is communicated with a second annular groove of the vacuumizing inner cavity (2), and the pressure gauge (5) detects and displays a gas pressure value in the second annular groove of the vacuumizing inner cavity (2);

the exhaust switch (6) is a sixth cylinder, the sixth cylinder of the exhaust switch (6) is a revolving body, the upper surface of the sixth cylinder of the exhaust switch (6) is a sixth upper end circular plane, the side surface of the sixth cylinder of the exhaust switch (6) is a sixth outer cylindrical surface, and the lower end of the sixth outer cylindrical surface of the exhaust switch (6) is provided with a sixth external thread;

the axis of a revolving body of the exhaust switch (6) is parallel to the axis of a revolving body of the power piston (1), a sixth outer cylindrical surface of the exhaust switch (6) is in sliding fit contact with the inner cylindrical surface of the second right end of the vacuumizing inner cavity (2), a sixth outer thread of the exhaust switch (6) is in inner thread fit with the second right end of the vacuumizing inner cavity (2), and a sixth upper end circular plane of the exhaust switch (6) is flush with the upward concentric circular ring surface of the second lower end of the vacuumizing inner cavity (2).

The ratio of the diameter of the first cylindrical boss of the power piston (1) to the diameter of the first outer cylindrical surface of the power piston (1) is 1: 3-4;

the ratio of the axial length of the first outer cylindrical surface of the power piston (1) to the diameter of the first outer cylindrical surface of the power piston (1) is 1: 5-6;

a handheld infrared tester is arranged outside the device, the handheld infrared tester is used for testing the gas pressure inside the vacuumizing inner cavity (2), and pressure data are obtained in a digital display mode;

step 1: placing the vacuumizing inner cavity (2) on a horizontal table;

step 2: assembling a power piston (1) with a vacuumizing inner cavity (2);

and step 3: assembling the vacuum-pumping hose (3) with the vacuum-pumping inner cavity (2);

and 4, step 4: assembling a vacuum-pumping switch (4) with a vacuum-pumping inner cavity (2);

and 5: assembling a pressure gauge (5) with the vacuumizing inner cavity (2);

step 6: assembling an exhaust switch (6) with the vacuumizing inner cavity (2);

and 7: when the gas pressure of the closed space needs to be reduced: the vacuumizing switch (4) is rotated clockwise and screwed until the fourth upper end circular plane of the vacuumizing switch (4) is flush with the upward concentric circular ring surface of the second lower end of the vacuumizing inner cavity (2); the exhaust switch (6) rotates anticlockwise until being dismounted; the power piston (1) rotates clockwise to the lowest position until the first lower end circular plane of the power piston (1) contacts with the second lower end upward concentric circular ring surface of the vacuum-pumping inner cavity (2); then the exhaust switch (6) is rotated clockwise and screwed until the sixth upper end circular plane of the exhaust switch (6) is flush with the upward concentric circular ring surface of the second lower end of the vacuum-pumping inner cavity (2); the vacuumizing switch (4) rotates anticlockwise and is loosened until a fourth upper end circular plane of the vacuumizing switch (4) is flush with the lower surface of a second annular groove of the vacuumizing inner cavity (2); then the power piston (1) is rotated anticlockwise to the uppermost position until the first upper end circular plane of the power piston (1) is contacted with the downward concentric circular ring surface of the second upper end of the vacuum-pumping inner cavity (2); thus, the closed space is exhausted once, so that the gas pressure of the closed space is reduced;

and step 9: when it is desired to increase the gas pressure in the enclosed space: the vacuumizing switch (4) is rotated clockwise and screwed until the fourth upper end circular plane of the vacuumizing switch (4) is flush with the upward concentric circular ring surface of the second lower end of the vacuumizing inner cavity (2); the exhaust switch (6) rotates anticlockwise until being dismounted; rotating the power piston (1) to the uppermost position anticlockwise until a first upper end circular plane of the power piston (1) is contacted with a downward concentric circular ring surface of a second upper end of the vacuumizing inner cavity (2); then the exhaust switch (6) is rotated clockwise and screwed until the sixth upper end circular plane of the exhaust switch (6) is flush with the upward concentric circular ring surface of the second lower end of the vacuum-pumping inner cavity (2); the vacuumizing switch (4) rotates anticlockwise and is loosened until a fourth upper end circular plane of the vacuumizing switch (4) is flush with the lower surface of a second annular groove of the vacuumizing inner cavity (2); then the power piston (1) is rotated clockwise to the lowest position until the first lower end circular plane of the power piston (1) is contacted with the upward concentric circular ring surface of the second lower end of the vacuumizing inner cavity (2); thus, the gas filling of the closed space is completed once, so that the gas pressure of the closed space is increased;

step 10: and (5) repeating the step (9), gradually filling gas into the closed space to gradually increase the gas pressure of the closed space, waiting for 3-5 minutes after the step (9) is finished each time, and then performing the step (9) again until the gas pressure of the closed space reaches a preset value.

2. A method for calibrating pressure using a hand-held infrared device according to claim 1, characterized in that the ratio of the diameter of the first cylindrical projection of the power piston (1) to the diameter of the first outer cylindrical surface of the power piston (1) is 1: 3;

the ratio of the axial length of the first outer cylindrical surface of the power piston (1) to the diameter of the first outer cylindrical surface of the power piston (1) is 1: 5.

3. a method for calibrating pressure using a hand-held infrared device according to claim 1, characterized in that the ratio of the diameter of the first cylindrical projection of the power piston (1) to the diameter of the first outer cylindrical surface of the power piston (1) is 1: 4;

the ratio of the axial length of the first outer cylindrical surface of the power piston (1) to the diameter of the first outer cylindrical surface of the power piston (1) is 1: 6.