Standard sample release device

Abstract

The utility model discloses a standard sample release device which comprises a liquid container, a barrier layer and a fixing cover, the top of the liquid container is open, the barrier layer is arranged at the opening of the liquid container, and the fixing cover is detachably arranged at the top of the liquid container and located on the outer side of the barrier layer; the barrier layer comprises a barrier film and an insulating film, the barrier film covers the opening of the liquid container, the insulating film is arranged above the barrier film, and release holes are formed in the insulating film. According to the utility model, the barrier layer composed of the barrier film and the insulating film ensures the stability of the emission rate by utilizing the characteristic that the distribution coefficients of the two surfaces of the barrier film are inconsistent, and the influence of the VOC concentration and the air velocity in the environment on the release rate can be avoided, so that the problem of unstable release rate in the prior art is avoided, and the service life of the film is prolonged. And the release rate is adjusted by adjusting the aperture of the release holes in the insulating film, so that the operation is more convenient, and the engineering application is more convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of indoor environment detection, in particular to a standard sample release device. Background Art

[0002] Indoor volatile organic compounds (VOC) are important factors affecting indoor air quality. These VOC sources mainly come from various decoration materials. At present, many relevant standards are used to detect the VOC release of these decoration materials, among which environmental chambers are widely used in these standards. The performance of the environmental chamber itself before detection largely determines the accuracy of the test results. At present, the evaluation of the performance of the environmental chamber mainly relies on the test calibration of standard release samples, such as polymethylpentene film standard emission samples, liquid-film emission standard samples, etc. The main structure of the test calibration method of the currently disclosed liquid-film standard release sample is composed of a tube containing analytically pure and a barrier film at the mouth of the tube, such as the standard release sample disclosed in CN219434769U, which has the advantages of being directly used for environmental chamber evaluation without a gas system, constant emission rate under given conditions, and long duration of the emission process. However, the polytetrafluoroethylene membrane used in the above-mentioned standard release sample still has the disadvantages that the emission rate is unstable when the environmental VOC concentration changes greatly, and the release rate adjustment is more troublesome. The utility model provides a standard release sample device to solve the above problems. Utility Model Content

[0003] The utility model provides a standard sample release device, which adopts a barrier layer composed of a barrier film and an insulating film and utilizes the characteristics of inconsistent distribution coefficients on both sides of the barrier film to ensure the stability of the emission rate.

[0004] The technical solution adopted by the utility model to solve the above technical problems is:

[0005] A standard release sample device comprises a liquid container, a barrier layer and a fixed cover, wherein the top of the liquid container is open, the barrier layer is arranged at the opening of the liquid container, and the fixed cover is detachably arranged on the top of the liquid container and is located on the outside of the barrier layer; the barrier layer comprises a barrier film and an insulating film, the barrier film covers the opening of the liquid container, the insulating film is arranged above the barrier film, and a release hole is provided on the insulating film.

[0006] Furthermore, the bottom surface of the barrier film is a frosted surface, and the top surface is a smooth surface.

[0007] Furthermore, the insulating film is laminated on the barrier film.

[0008] Furthermore, a diffusion hole is provided on the fixing cover, and a diameter of the diffusion hole is larger than a diameter of the release hole.

[0009] Furthermore, the thickness of the barrier film is 0.1 mm.

[0010] Furthermore, the barrier film is aluminum oxide paper, and the insulating film is aluminum foil film.

[0011] Furthermore, the fixed cover is threadedly connected to the liquid container.

[0012] The beneficial effects of the utility model are as follows:

[0013] The barrier layer composed of a barrier film and an insulating film utilizes the inconsistent distribution coefficients on both sides of the barrier film to ensure the stability of the emission rate. The above characteristics can avoid the influence of the concentration of VOCs in the environment and the air flow rate on the release rate, thereby avoiding the problem of unstable release rate in the prior art. In addition, the release rate can be adjusted by adjusting the aperture of the release hole on the insulating film, which makes the operation more convenient and more convenient for engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0015] Figure 2 It is a schematic diagram of the overall structure of the utility model in the packaging state;

[0016] Figure 3 It is a schematic diagram of the internal structure of the utility model;

[0017] Figure 4 This is a schematic diagram of the barrier layer structure of the utility model;

[0018] Figure 5 It is a schematic diagram of the experimental data fitting equation of the utility model.

[0019] Figure numerals: 1, liquid container; 2, barrier layer; 21, barrier film; 22, insulating film; 221, release hole; 3, fixed cover; 31, diffusion hole. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings of the specification to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0022] like Figure 1 , 2 As shown in FIGS. 3 and 5, the working principle of the present invention is to utilize the inconsistent distribution coefficients of the upper and lower surfaces of the barrier film 21, the distribution coefficient of the top interface is small, and the distribution coefficient of the bottom interface is large, thereby achieving a stable release rate. The release rate formula during the steady-state release process is:

[0023]

[0024] in is the release rate of the emission source, in kg / s; C sat is the concentration of pure saturated steam of VOC in the standard release sample tube, in kg / m3; C a is the concentration of VOC in the environment, in kg / m3; K1 is the interface distribution coefficient at the bottom of the barrier membrane, with no unit; K2 is the interface distribution coefficient at the top of the barrier membrane, with no unit; h m is the convection mass transfer coefficient, in m / s, A is the release area of ​​the barrier film, in m2; L is the thickness of the barrier film, in m; D is the diffusion coefficient of VOC in the barrier film, in m2 / s; Since K2<<K1, K2C a Much smaller than K1C sat , environmental concentration C a The change of will not cause large fluctuations in the release rate, thus ensuring the stability of the release rate.

[0025] like Figure 1 , 2, 3, and 4, according to a specific embodiment determined by the release formula, the standard release sample device includes a liquid container 1, a barrier layer 2, and a fixed cover 3. The liquid container 1 adopts a polytetrafluoroethylene cylindrical container with an open top, and its outer diameter is 36 mm, the inner diameter is 30 mm, the wall thickness is 3 mm, the net height is 40 mm, and the base thickness is 5 mm. Toluene is injected into the release device as a VOC analytical pure liquid, and the liquid volume is two-thirds of the liquid container 1; the barrier layer 2 is arranged at the opening of the liquid container 1, and the barrier layer 2 includes a barrier film 21 and an insulating film 22. The barrier film 21 covers the opening of the liquid container 1, and aluminum oxide frosted paper is adopted. The bottom surface of the barrier film 21 is a frosted surface with a large distribution coefficient, and the top surface is a smooth surface with a small distribution coefficient. The diameter of the barrier film 21 is 36 mm, and the thickness is 0.1 mm. The insulating film 22 is Above the barrier film 21, an insulating aluminum foil tape is used, and its diameter is 36 mm. The insulating film 22 is provided with a release hole 221, and the diameter of the release hole 221 is 6 mm. The VOC analytical pure liquid passes through the barrier film 21 and is released through the release hole 221 on the insulating film 22. The fixed cover 3 is connected to the top of the liquid container 1 by a thread, and is located on the outside of the barrier layer 2 to fix the barrier layer 2 at the opening of the liquid container 1 and achieve sealing, so that VOC can only pass through the barrier film 21 and then be released through the release hole 221 on the insulating film 22, thereby ensuring that the VOC emission rate remains stable and avoiding the influence of the VOC concentration and air flow rate in the environment on the release rate. The fixed cover 3 is provided with a diffusion hole 31, and the diameter of the diffusion hole 31 is larger than the diameter of the release hole 221 to avoid affecting the release and diffusion of the sample.

[0026] like Figure 1 , 2 As shown in FIGS. 3 and 4 , further, the insulating film 22 is laminated on the barrier film 21 to prevent VOC from passing through the gap between the insulating film 22 and the barrier film 21 .

[0027] Furthermore, the insulating film 22 is an insulating aluminum foil tape, which can isolate VOCs from passing through, so that after VOCs pass through the barrier film 21 , they can only be released through the release holes 221 on the insulating film 22 .

[0028] The specific detection method of the utility model is as follows:

[0029] S1, injecting toluene as a VOC analytical pure liquid into a liquid container 1, laminating a barrier film 21 and an insulating film 22 with parameters determined in a specific embodiment and placing them at the mouth of the liquid container 1, and then tightening a fixing cover 3 to fix and seal the barrier layer 2 to form a standard release sample;

[0030] S2, set the parameters of the experimental environment to the required values, the experimental environment is constant temperature and humidity, the temperature is 25±0.5℃, and the humidity is 50%;

[0031] S3, placing the assembled standard release sample in the experimental environment to calibrate its mass decay rate, and measuring the mass of the standard release sample with an electronic balance every 12 hours for 3 consecutive days;

[0032] S4, measure the mass of the standard release sample according to the design requirements, and fit the linear equation of mass m (g)-time t (min) according to the measured data: m = -5.81 × 10-5t + 57.424 (g). According to the slope, the release rate of the standard emission sample is 5.81 × 10-5 ± 7.57 × 10-7 g / min, i.e. 0.968 ± 0.013 μg / s;

[0033] S5, changing the diameter parameter of the release hole 221 on the insulating membrane 22, changing the release rate of the standard emission sample, so that the release rate varies within the range of 0 to 24 μg / s, and then obtaining a corresponding parameter table, and then performing engineering applications based on the obtained parameter data.

[0034] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

Claims

1. A standard release sample device, characterized in that: The invention comprises a liquid container (1), a barrier layer (2) and a fixed cover (3), wherein the top of the liquid container (1) is open, the barrier layer (2) is arranged at the opening of the liquid container (1), and the fixed cover (3) is detachably arranged on the top of the liquid container (1) and is located outside the barrier layer (2); The barrier layer (2) comprises a barrier film (21) and a substance-isolating film (22); the barrier film (21) covers the opening of the liquid container (1); the substance-isolating film (22) is arranged above the barrier film (21); and a release hole (221) is provided on the substance-isolating film (22).

2. A standard release sample device according to claim 1, characterized in that: The bottom surface of the barrier film (21) is a frosted surface, and the top surface is a smooth surface.

3. A standard release sample device according to claim 1, characterized in that: The insulating film (22) is laminated on the barrier film (21).

4. A standard release sample device according to claim 1, characterized in that: The fixed cover (3) is provided with a diffusion hole (31), and the diameter of the diffusion hole (31) is greater than the diameter of the release hole (221).

5. A standard release sample device according to claim 1, characterized in that: The thickness of the barrier film (21) is 0.1 mm.

6. A standard release sample device according to claim 1, characterized in that: The barrier film (21) is aluminum oxide paper, and the insulating film (22) is aluminum foil.

7. A standard release sample device according to claim 1, characterized in that: The fixed cover (3) is threadedly connected to the liquid container (1).

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