Push can for reference gas
The push can design with a single gas inlet and specific materials ensures stable, long-term low-concentration ethanol supply for alcohol detectors, addressing the challenges of high-pressure cylinders and leakage issues in existing ethanol standard gas containers.
Patent Information
- Application Number
- JP2023223538
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2025-07-10
AI Technical Summary
High-pressure gas cylinders used for ethanol standard gas are cumbersome, expensive, and difficult to handle, while low-concentration ethanol in push cans loses concentration over time due to leakage, making them unsuitable for long-term use in alcohol detectors.
A push can design with a can body filled with ethanol standard gas and a push-type injection device featuring a single gas inlet on the bottom wall, utilizing a polybutylene terephthalate housing and nitrile rubber packing to maintain low-concentration ethanol at a low pressure for extended periods.
The push can maintains stable ethanol concentration for over 550 days, is lightweight and easy to handle, and reduces costs compared to high-pressure cylinders.
Smart Images
Figure 2025105174000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a push can for standard gas filled with ethanol standard gas, and mainly relates to a push can for standard gas suitable for sensitivity confirmation for calibration of an alcohol detector.
Background Art
[0002] Business operators who own a certain number or more of motor vehicles are obliged to conduct alcohol checks on drivers before and after driving. An alcohol detector (drinking detector) for conducting an alcohol check is specifically a detector that detects ethanol, and it is required to periodically check its sensitivity. It is desirable to check the sensitivity by spraying ethanol at the concentration to be actually detected onto the alcohol detector and confirming whether the detector can accurately detect it without problems. This is because if the detector does not operate due to this sensitivity check, it cannot function as a detector even when ethanol actually exists. Currently, for the ethanol standard gas used for checking the sensitivity of alcohol detectors, a standard gas of a predetermined concentration filled in a high-pressure gas cylinder is used. Also, it is filled in a high-pressure gas cylinder at a high pressure such as 9.8 MPa, 11.7 MPa, 11.8 MPa, 14.7 MPa, etc. Therefore, conventionally, no push cans filled with ethanol standard gas at a filling pressure lower than 1 MPa have been developed or manufactured.
Summary of the Invention
Problems to be Solved by the Invention
[0003] As described above, for the ethanol standard gas, a high-pressure standard gas filled in a high-pressure gas cylinder is used. However, a high-pressure gas cylinder is heavy, requires a pressure regulating device, is more troublesome to transport and handle, and is expensive. Also, storage is strictly regulated by the High-Pressure Gas Safety Act and is difficult for ordinary people who are not specialized in chemistry to handle.
[0004] On the other hand, when a push can used for other standard gases is filled with low-concentration ethanol, the ethanol concentration gradually decreases over time and becomes unusable as standard gas after about two months. This is considered to be due to leakage over time.
[0005] Here, in this specification, "low concentration" refers to a concentration of about 0.05 mg / L to 0.40 mg / L. Legally, the level at which a drunk driving offense is detected is 0.15 mg / L. Article 44-3 of the Ordinance for the Enforcement of the Road Traffic Act stipulates that "the level of alcohol held in the body as determined by Cabinet Order in Article 117-2-2, Paragraph 1, Item 3 of the Act shall be 0.3 mg (milligrams) per 1 mL (milliliter) of blood or 0.15 milligrams per 1 L (liter) of breath." Since it is assumed that no alcohol is consumed when driving is permitted, it is desirable to be able to confirm that the ethanol concentration in the breath is less than 0.05 mg / L. Therefore, as a sensitivity confirmation gas for an alcohol detector, a low-concentration gas of about 0.05 mg / L to 0.40 mg / L is desired.
[0006] An object of the present invention is to solve the problems when filling ethanol standard gas into a high-pressure gas cylinder, and to provide a push can for standard gas that can maintain a standard gas of low-concentration ethanol at a low pressure while maintaining a predetermined low-concentration range for a long period of time.
Means for Solving the Problems
[0007] To solve the above problems, a push can for standard gas according to the present invention includes a can body filled with ethanol standard gas, and a push-type injection device attached to the upper lid of the can body. The push can for standard gas is characterized in that the injection device includes a bottomed cylindrical housing fixed to the back surface of the upper lid, an annular packing sandwiched between the upper lid and the upper end of the housing, a stem fitted into the housing and protruding upward through the packing and the upper lid, and a spring for biasing the stem to an upper closed position. An outlet passage having an outlet port and an opening / closing passage communicating with the outlet passage and reaching the outer peripheral surface of the stem are formed in the stem. The stem is slidable in the vertical direction between the closed position where the opening / closing passage is blocked by the inner peripheral surface of the annular packing and the open position where the opening / closing passage is opened from the inner peripheral surface of the annular packing below the closed position. The bottom wall of the housing has a single gas inlet communicating the bottom space of the housing communicating with the opening / closing passage in the open state and the inside of the can body.
[0008] In the above configuration, preferably, the aperture diameter of the gas inlet is 2.0 mm, or an inlet pipe protruding downward from the gas inlet is formed on the bottom wall of the housing. Also, the material of the housing is preferably polybutylene terephthalate. Further, the material of the annular packing is preferably nitrile rubber having a rubber hardness of 62° or more and 65° or less.
Advantages of the Invention
[0009] Since only one gas inlet for taking standard gas from the inside of the can body into the injection device is formed on the bottom wall of the housing, even when the push can is filled with low-concentration ethanol, it can be maintained in a stable state without reducing the concentration for a long time. Also, since a push can with a low filling pressure can be used, the supply operation of ethanol standard gas to the alcohol detector can be performed easily and conveniently.
Brief Description of the Drawings
[0010]
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Embodiments for Carrying Out the Invention
[0011] [Embodiments of the Present Invention] Based on FIGS. 1 to 5, the structure of a push can for standard gas according to an embodiment of the present invention will be described. FIG. 1 is a front view of a push can 1 for standard gas filled with ethanol standard gas. In FIG. 1, the push can 1 for standard gas includes a cylindrical can body 2 made of metal, an aluminum upper lid 3 fixed to the upper end of the can body 2, and an injection device 5 disposed on the back side of the upper lid 3. The injection device 5 has a brass stem 6 that penetrates the upper lid 3 and protrudes upward, and a push button 8 is mounted on the upper end portion of the stem 6. An extension nozzle 10 extending in a direction orthogonal to the stem axis line O1 (vertical direction) is connected to the push button 8. The upper end portion of the can body 2 is formed in a tapered shape.
[0012] FIG. 2 is an enlarged longitudinal sectional view of the injection device 5 in a closed state. In FIG. 2, the push button 8 has a downward-opening recess 8a into which the upper end portion of the stem 6 is fitted, and a gas passage 8b extending in a direction orthogonal to the stem axis line O1. The recess 8a and the gas passage 8b communicate with each other. When using the push can, the recess 8a is connected to the upper end portion of the stem 6, and the extension nozzle 10 is connected to the outlet end portion of the gas passage 8b.
[0013] A cylindrical portion 3a protruding upward is formed in the central portion of the upper lid 3, and an opening 11 through which the stem 6 passes is formed in the top wall 3b of the cylindrical portion 3a. The outer peripheral end portion of the upper lid 3 is coupled to the upper end portion of the can body 2 via an annular seal 12.
[0014] The injection device 5 includes the brass stem 6, a resin housing 15 into which a sliding portion 6a of the lower half of the stem 6 is fitted, and an annular packing 16 made of nitrile rubber.
[0015] The housing 15 is formed in a bottomed cylindrical shape and is inserted into the cylindrical portion 3a of the upper lid 3. The material of the housing 15 is polybutylene terephthalate in this embodiment. At the upper end of the housing 15, a stepped packing seating surface 30 is formed, and an annular packing 16 is seated on this packing seating surface 30. The annular packing 16 is in pressure contact with the back surface of the top wall 3b of the cylindrical portion 3a. The upper end portion of the housing 15 is held by the cylindrical portion 3a of the upper lid 3 with a certain pressure from the outer side in the radial direction while pressing the annular packing 16 upward.
[0016] At the center of the bottom wall 15a of the housing 15, a sole gas inlet 25 that communicates the bottom space 42 inside the housing 15 and the inside of the can body 2 is formed. The gas inlet 25 is a through hole with a diameter of 2 mm. Further, an inlet pipe 26 extending downward from the gas inlet 25 is integrally formed with the housing 15 on the bottom wall 15a. On the inner peripheral surface of the housing 15, a vertical groove (vertical passage) 41 extending from the packing seating surface 30 at the upper end to the bottom wall 15a is formed.
[0017] The stem 6 is formed in a columnar shape extending in the vertical direction. Inside the upper half of the stem 6, an outlet passage 31 extending along the stem axis line O1 is formed. The upper end of the outlet passage 31 opens upward as a jet outlet 31a. An annular groove 33 is formed on the outer peripheral surface at the central portion in the vertical direction of the stem 6. The annular groove 33 and the lower end portion of the outlet passage 31 communicate with each other through a radially extending opening / closing passage 32. The inner peripheral end portion of the annular packing 16 projects into the annular groove 33, and the opening / closing passage 32 is blocked by the inner peripheral surface of the annular packing 16. Also, the upper surface of the annular groove 33 is a tapered surface 33a that expands in diameter upward.
[0018] The sliding portion 6a of the stem 6 is fitted movably in the direction of the stem axis line O1 on the inner peripheral surface of the housing 15. A coil spring 40 is contracted between a downward annular step surface 35 formed on the sliding portion 6a and an upward spring seating surface 36 formed on the bottom wall 15a of the housing 15. Due to the elastic force of the coil spring 40, the stem 6 is biased to the upper closed position (the position in FIG. 2).
[0019] Figure 3 is a cross-sectional view taken along line III-III of the injection device 5 in Figure 2. In Figure 3, a plurality of slits 37 are formed on the outer peripheral surface of the upper end portion of the housing 15 at equal intervals in the circumferential direction. When these slits 37 are provided, when the upper end portion of the housing 15 is tightened by the cylindrical portion 3a, the upper end portion of the housing 15 can be tightened almost evenly over the entire circumference. Thereby, the annular seal 16 can be firmly held.
[0020] Figure 4 is an enlarged cross-sectional view taken along line IV-IV of Figure 2. In Figure 4, the longitudinal grooves 41 on the inner peripheral surface of the housing 15 are formed at a plurality of locations at equal intervals in the circumferential direction.
[0021] Figure 5 is an enlarged longitudinal sectional view of the injection device 5 in the open state. In Figure 5, by the push button 8, the stem 6 is pushed down to the lower open position against the elastic force of the coil spring 40. In the process of the stem 6 descending from the closed position in Figure 2, the tapered surface 33a of the annular groove 33 expands the inner peripheral surface of the annular packing 16 while the stem 6 moves to the lower open position. In the open position, the annular groove 33 is disengaged downward from the inner peripheral surface of the annular packing 16, and the opening and closing passage 32 of the stem 6 is opened on the outer peripheral surface of the stem 6. That is, the opening and closing passage 32 communicates with the bottom space 42 through the annular groove 33 and the longitudinal groove 41. Thereby, the ethanol standard gas at a predetermined pressure in the can body 2 passes through the inlet pipe 26, the gas inlet 25, the bottom space 42, the longitudinal groove 41, the annular groove 33 of the stem 6, the opening and closing passage 32, the outlet passage 31, the gas passage 8b of the push button 8, and the extension nozzle 10, and is ejected to the outside.
[0022] After use, when the finger is released from the push button 8, the stem 6 returns to the closed position in Figure 2 by the elastic force of the coil spring 40, and the opening and closing passage 32 is closed by the inner peripheral surface of the annular packing 16. That is, the injection device 5 returns to the closed state.
[0023] [Time-dependent characteristics of the push can under various different conditions] The graphs in FIGS. 6 to 11, 13, and 14 show the time-dependent characteristics of the push can under various different conditions, that is, the change in ethanol concentration over time. In each graph, the horizontal axis represents the number of days elapsed after gas filling, and the vertical axis represents the indicated value of ethanol concentration. However, the indicated values on the vertical axis in FIGS. 6 and 7 show the DPA indicated values by a reliable alcohol detector for testing, and the indicated values on the vertical axis in FIGS. 8 to 11, 13, and 14 show the values obtained by converting the ethanol concentration from the amount of ethanol detected by a gas chromatograph mass spectrometer. Also, in each graph, the upper and lower horizontal lines (L1, L2) shown by the two-dot chain line are the allowable upper limit value L1 and the allowable lower limit value L2 for a predetermined concentration. Specifically, the allowable upper limit value L1 is a value of +10% with respect to the predetermined concentration, and the allowable lower limit value L2 is a value of -10% with respect to the predetermined concentration. The measurement frequency is 4 times on each measurement day, and their average values are shown on the graph by white triangle marks or white square marks. Further, the maximum value and the minimum value of the 4 measurements are shown by thick horizontal bars above and below the white triangle marks or white square marks, respectively. Also, in FIGS. 6 and 7, the change in ethanol concentration when filled in a high-pressure gas cylinder is shown by the graph of white circle marks.
[0024] (Difference in Time-Dependent Characteristics Due to Difference in Gas Inlet Shape) FIGS. 6 and 7 show the difference in time-dependent characteristics due to the different gas inlet shapes. FIG. 6 shows the time-dependent characteristics when an ethanol standard gas with an ethanol concentration of 0.390 mg / L is filled in the push can 101 for propane standard gas shown in FIG. 15. The configuration of the standard gas push can 101 in FIG. 15 that is different from the standard gas push can 1 in FIG. 2 of the present embodiment is that the material of the housing 151 in FIG. 15 is polyacetate, and a plurality of gas inlets 125 communicating the bottom space 42 of the housing 151 and the inside of the can body 2 are formed on the peripheral wall of the housing 151. Other configurations are the same as those in FIG. 2, and the main parts with the same names are assigned the same numbers.
[0025] FIG. 16 is a cross-sectional view taken along line XVI-XVI of FIG. 15, and for example, 3 gas inlets 125 are formed at equal intervals in the circumferential direction.
[0026] In the change of the ethanol concentration of the conventional product shown in Fig. 6, 60 days after filling, the 4-time average value indicated by the open triangle mark has already decreased to near the allowable lower limit value L2. After that, it continues to decrease. At the time point of 300 days, it has decreased to around 0.300 mg / L.
[0027] Fig. 7 shows the time-dependent characteristics when the standard gas push can 1 of the present embodiment described in Figs. 1 to 5 is filled with an ethanol standard gas having the same ethanol concentration of 0.390 mg / L as in Fig. 6. In addition, in any of the structures of Figs. 1 to 5 and Fig. 15, the annular packing 16 has a rubber hardness of 65, and the filling pressure is 0.68 MPa.
[0028] In the change of the ethanol concentration shown in Fig. 7, even after 550 days from filling, it remains within the range of the allowable upper limit value L1 and the allowable lower limit value L2. In particular, it remains within a narrow range of 0.360 mg / L to 0.370 mg / L, and it can be understood that it is possible to maintain a stable ethanol concentration for a long period within a small fluctuation range.
[0029] From such a comparison, it can be seen that the structure in which the sole gas inlet 25 is provided on the bottom wall 15a of the housing 15 as shown in Fig. 7 can maintain the long-term stability of the ethanol concentration. On the contrary, in the structure in which the gas inlet 125 is formed on the peripheral wall of the housing 151 as shown in Fig. 15, the stability of the ethanol concentration is low.
[0030] (Difference in time-dependent characteristics due to difference in rubber hardness of annular packing 16) Figs. 8 to 11 show the differences in time-dependent characteristics when the rubber hardness of the annular packing 16 is set to four types of 58 degrees, 62 degrees, 65 degrees, and 69 degrees in the standard gas push can 1 having the structure of Figs. 1 to 5. The predetermined concentration of ethanol is lower than that in Figs. 6 and 7 described above and is 0.205 mg / L.
[0031] Fig. 8 shows the time-dependent characteristics when the annular packing 16 with a rubber hardness of 58 degrees is used. After 180 days, the ethanol concentration fluctuates so as to largely cross the allowable lower limit value L2 up and down.
[0032] Figure 9 shows the characteristics over time when the annular packing 16 with a rubber hardness of 62 degrees is used. Near the 330th day, the ethanol concentration has decreased to near the allowable lower limit value L2, but it does not decrease below the allowable lower limit value L2. It does not fall below the allowable lower limit value L2 until the 420th day, maintaining the stability of the ethanol concentration.
[0033] Figure 10 shows the characteristics over time when the annular packing 16 with a rubber hardness of 65 degrees is used. The ethanol concentration remains between the allowable upper limit value L1 and the allowable lower limit value L2 until the 420th day, and in particular, it remains within a narrow range from 0.225 mg / L to 0.195 mg / L. That is, a high degree of stability is maintained until the 420th day.
[0034] Figure 11 shows the characteristics over time when the annular packing 16 with a rubber hardness of 69 degrees is used. The ethanol concentration is lower than the allowable lower limit value of 0.180 mg / L on the 300th day and the 420th day.
[0035] From these comparisons, in the structure of the push can 1 for standard gas shown in FIGS. 1 to 5, it can be seen that by installing the annular packing 16 with a rubber hardness of 62 to 65 degrees, the long-term stability of the ethanol concentration can be maintained. In particular, it can be determined that a rubber hardness of about 65 is optimal.
[0036] (Differences in stability over time due to differences in base gas) FIGS. 13 and 14 show the characteristics over time when filling the push can structure of FIGS. 1 to 5 with an ethanol standard gas of a predetermined concentration. In FIG. 13, nitrogen N2 is used as the base gas, and in FIG. 14, air is used as the base gas. The annular packing 16 uses a rubber hardness of 65 degrees.
[0037] Figure 13 shows the characteristics over time when nitrogen N2 is used as the base gas and filled with ethanol at a predetermined concentration of 0.050 mg / L. The ethanol concentration maintains approximately the predetermined concentration of 0.050 mg / L until the 220th day of elapsed days. Also, the vertical range between the maximum value and the minimum value at the time of the four measurements is extremely small. That is, it has a high degree of stability.
[0038] Figure 14 shows the characteristics over time when air is used as the base gas and ethanol with a predetermined concentration of 0.045 mg / L is filled. The ethanol concentration maintains near the allowable upper limit value L1 (0.050 mg / L) until 220 days have elapsed, but does not exceed the allowable upper limit value L1. That is, compared with Figure 13 based on nitrogen described above, the characteristics are biased towards the allowable upper limit value L1 side, but the stability of the ethanol concentration is maintained.
[0039] [Effects according to the embodiment] (1) By forming only one gas inlet 25 for taking the ethanol standard gas in the push can 1 into the injection device 5 on the bottom wall 15a of the housing 15, the low-concentration and low-pressure ethanol standard gas can be stably held in the push can 1 for a long time.
[0040] (2) By setting the rubber hardness of the annular packing 16 to 62 degrees to 65 degrees, the leakage of the standard gas can be reduced well, and the stability of the ethanol concentration can be enhanced.
[0041] (3) Since the lightweight push can 1 is filled with the low-concentration and low-pressure ethanol standard gas compared with the high-pressure cylinder, it is economical, easy to handle, and the cost can also be reduced.
[0042] [Other embodiments] (1) The annular packing is not limited to nitrile rubber, and other rubber members can also be used.
[0043] Although several embodiments of the present invention have been described, each of the above embodiments is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.
Explanation of reference numerals
[0044] 1 Push can for standard gas 2 Can body 3 Upper lid 5 Injection device 6 Stem 8 Push button 10 Extension nozzle 15 Housing 15a Bottom wall 16 Annular packing 25 Gas inlet 31 Outlet passage 32 On-off passage 40 Coil spring 42 Bottom space
Claims
1. A push can for standard gas, comprising a can body filled with standard ethanol gas and a push-type injection device mounted on the upper lid of the can body, wherein the injection device comprises a bottomed cylindrical housing fixed to the back surface of the upper lid, an annular packing sandwiched between the upper lid and the upper end of the housing, a stem fitted into the housing, penetrating through the packing and the upper lid and protruding upward, and a spring for biasing the stem to an upper closed position, wherein an outlet passage having an outlet port and an opening / closing passage communicating with the outlet passage and reaching the outer peripheral surface of the stem are formed in the stem, the stem is slidable in the vertical direction between the closed position where the opening / closing passage is blocked by the inner peripheral surface of the annular packing and the open position below the closed position where the opening / closing passage is opened from the inner peripheral surface of the annular packing, and the bottom wall of the housing has a sole gas inlet communicating a bottom space of the housing communicating with the opening / closing passage in the open state and the inside of the can body. A push can for standard gas.
2. The push can for standard gas according to claim 1, wherein the aperture diameter of the gas inlet is 2.0 mm.
3. The push can for standard gas according to claim 1 or 2, wherein an inlet pipe protruding downward from the gas inlet is formed on the bottom wall of the housing.
4. The push can for standard gas according to claim 1 or 2, wherein the material of the housing is polybutylene terephthalate.
5. The push can for standard gas according to claim 1 or 2, wherein the material of the annular packing is nitrile rubber with a rubber hardness of 62 to 65 degrees.