JP3568239B2 - Powder dry ice manufacturing equipment - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an apparatus for producing powdered dry ice used for maintaining freshness of fresh food, frozen food, processed food, and the like.
[0002]
[Prior art]
Conventionally, an apparatus for producing liquefied carbon dioxide gas for producing powdered dry ice, for example, as shown in FIG. 1, has a nozzle 3 provided at the base end of a horizontal portion 2 of a passage 1 having a rectangular or circular cross section, into a passage inside the passage. The liquefied carbon dioxide gas to be ejected is ejected into the tapered chamber 4 having a tapered shape, and a notch-shaped opening 7 is formed outside a middle portion of the arc-shaped portion 6 formed at the tip of the horizontal portion 2 continuous with the tapered chamber 4. A discharge port 8 is provided at the tip of the arc-shaped portion. That is, when the liquefied carbon dioxide gas supplied from a pipe (not shown) is jetted into the tapered chamber 4 through the nozzle 3, the temperature is rapidly lowered due to adiabatic expansion due to a rapid pressure change, and the carbon dioxide gas and the powder dry ice are reduced. And separated into The pressure gradually decreases because the volume increases as the gas advances in the taper chamber 4. As a result, the particles of the dry ice powder grow large, and the pressure gradually decreases over time. Although the distance between the nozzle 3 and the opening 7 is relatively short, powder dry ice is manufactured efficiently.
[0003]
Further, as shown in FIG. 2, the shape of the conventional reliquefaction nozzle is such that the tip of a pipe 1a is closed by a lid portion 9, a large number of holes 8a are provided at regular intervals in a wall surface, and the diameter is 6.35 mm. And 9.52 mm, and even 12.7 mm in different container volumes (not shown) such as 5 liters, 10 liters and 20 liters for storing liquefied nitrogen (LN2). The liquefaction nozzle 3a is inserted to take out liquefied gas such as liquid nitrogen inside the container. However, since the discharge pressure is high, liquid nitrogen does not stay in the pipe 1a much, and it takes much time to take out.
FIG. 3 shows a reliquefaction nozzle 3b which is a modification of FIG. 2 and has a large number of small holes on the wall surface of the sintered metal 9a which is attached to the end of the pipe 1b and closes the pipe. Although the performance of taking out liquefied nitrogen gas can be further improved, since the discharge pressure is still high, much time is required to take out liquefied gas.
[0004]
[Problems to be solved by the invention]
In the conventional production of powder dry ice, liquefied carbon dioxide (LCO2) ejected from a nozzle located in a horn is released to the atmosphere side in a state of a primary pressure gradient, and at the time when it is released from each nozzle. Dry ice passes through the triple point. However, the gas flow rate was high and the loss due to vaporization during adiabatic expansion was large, resulting in poor dry ice powder generation efficiency.
In the conventional generation of liquefied gas, liquefied gas ejected from a nozzle located in the horn is discharged to the atmosphere with a primary pressure gradient. However, since the gas flow rate at this time is high, there is a large loss due to vaporization during adiabatic expansion, and the conversion efficiency from the storage tank pressure to the atmospheric pressure is not improved. In addition, when the amount of dry ice powder is increased, the noise increases in proportion to the problem.
[0005]
According to the present invention, a nozzle and a horn portion, which are gas jetting portions, are improved, and nozzles are provided facing each other on slopes located on both sides of a small-diameter portion of a cylindrical main body, and jetted in a centrifugal direction from the nozzles. The liquefied gas is caused to collide with each other in the horn to form a pressure partition wall-like film, and the horn is divided into a plurality of sections to improve the efficiency of producing powder dry ice under the atmospheric pressure rather than the storage pressure. It is intended to improve.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention , a blind hole 32 is provided inside the main body 30 from one end, and 45-degree slope portions 35, 35 are continuously formed on both sides of a small diameter portion 34 provided on the outer peripheral surface of the main body. A plurality of nozzles 37, 37 formed at right angles to each slope, are provided at equal intervals in the circumferential direction, and a cylindrical horn 41 having an open end is provided outside the main body. A space 45 is provided and installed, and the gas ejected from each of the nozzles 37 facing each other is made to collide around the small diameter portion 34 to form a pressure partition-like membrane 19 formed in the centrifugal direction. The horn is provided in the horn having 46 so as to be separated from the atmosphere to prevent a sudden pressure drop.
The invention according to claim 2 is characterized in that a plurality of small-diameter portions 13, 13 are provided at regular intervals on an outer peripheral surface of a main body 10 having a blind hole 11 therein, and a 45-degree slope is continuously provided on both sides of each small-diameter portion. The parts 15, 15 are formed symmetrically facing each other, a plurality of nozzles 17 provided at right angles to each slope are formed in pairs at equal intervals in the circumferential direction, and an opening 23 is provided at the tip. A cylindrical horn 21 having an empty space 20 formed therein is provided outside of the main body 11 and installed, and gas ejected from each of the opposed nozzles 17 is collided with each other to form a pressure partition wall formed in a centrifugal direction. A plurality of membranes 19 are provided in the horn so as to be separated from the atmosphere to prevent a sudden pressure drop.
[0007]
[Action]
Slope portions are formed symmetrically on both sides of one or a plurality of small diameter portions provided on the outer periphery of the main body in communication with the blind holes provided in the main body, and the slope portions are formed at regular intervals in the circumferential direction. A plurality of nozzles are provided, and the gas ejected from the nozzles provided on the slope portion is caused to collide around each small diameter portion, thereby effectively utilizing the latent heat during adiabatic expansion to bring the vaporization loss close to the theoretical value. . In addition, one or a plurality of compartments are formed in the horn by a pressure partition-like membrane formed in the centrifugal direction by colliding gas ejected from nozzles provided opposite to each other to minimize a sudden pressure loss. To increase the production rate of powder dry ice .
[ 0008 ]
【Example】
The embodiment of the first aspect of the present invention will be described with reference to FIGS. 7 to 10. A blind hole 32 is formed from one end to substantially the other end inside a main body 30 having a fastening portion 31 on a head. A male screw 33 is formed on the upper outer peripheral surface of the main body 30. A small diameter portion 34 is formed on the outer periphery of the middle portion of the main body 30, and slope portions 35, 35 forming slopes of about 45 degrees are formed continuously on both sides of the small diameter portion 34 so as to face each other symmetrically. A plurality of small-diameter nozzles 37 (eight in this embodiment) are provided at equal intervals in the circumferential direction of the slope in the middle of the small-diameter slope. It is also possible to form a set of three. Further, the nozzle shape is formed in a size of 0.4 mm to 1.0 mm, preferably 0.6 mm, and the number of nozzles provided on the same circumference is 4 to 16, preferably 4 is there. One end of the nozzle 37 communicates with the blind hole 32, the other end communicates with the outside of the main body 30, and a cylindrical horn 41 is mounted on the outer periphery of the main body 30. A flat surface 43 for engaging a wrench (not shown) or the like is formed on both upper sides of the horn 41, and a female screw 44 with which the male screw 33 of the main body 30 is screwed is formed at the center of the upper part. A space 45 is provided on the inside below, and an opening 46 provided at the lower end communicates with the atmosphere. Reference numeral 48 denotes a female hole for connecting a pipe (not shown) formed at the upper end of the blind hole 32.
[ 0009 ]
When measuring using a horn having an inner diameter of 135 mm, 150 mm, or 165 mm around the main body 30, 135 mm and 150 mm produced liquefied gas favorably. Gas production rates varied. The distance between the peripheral wall surface around the main body 30 and the peripheral wall surface in the case where only one vacant chamber 45 is formed in the horn 41 is about 80 to 100 mm in horn diameter, and the powder dry ice generation efficiency Was the best.
[ 0010 ]
Next, an embodiment according to the second aspect of the present invention will be described with reference to the drawings. Referring to FIG. 4, a blind hole 11 is formed inside a rod-shaped main body 10 from one end to substantially the other end. A plurality of small diameter portions 13, 13 are formed at regular intervals on the outer peripheral surface of. On both sides of each small-diameter portion 13, slopes 15, 15, which form a slope of about 45 degrees, are formed so as to face each other symmetrically, and a middle part of each slope 15 is perpendicular to the slope. A plurality (eight in this embodiment) of small diameter nozzles 17 are bored at equal intervals in the circumferential direction of the slope. One end of the nozzle 17 communicates with the blind hole 11, and the other end communicates with the outside of the main body 10. A cylindrical horn 21 is mounted on the outer periphery of the main body 10. Communicates with the atmosphere side through an opening 23 provided in the air conditioner.
[ 0011 ]
Reference numeral 19 denotes a pressure partition-like membrane formed in a disk shape so as to partition the inside of a horn 21 located on the outer periphery of the main body 10 on the extension of the straight line 18 passing through the centers of the opposed nozzles 17 and 17. The horn 21 is divided into one or a plurality of stages to prevent a sharp pressure drop. Reference numeral 20 denotes an empty space formed on the outer periphery of the main body 10 and in the horn 21. The interior of the horn 21 is exposed from the back side to the first chamber 25, the second chamber 26, the third chamber 27 and the atmosphere. Fourth chambers 28 each having an opening 23 communicating therewith are formed.
[ 0012 ]
The main body 10 of this embodiment has, for example, an outer diameter of 17 mm and a total length of 100 mm, and is provided with a blind hole 11 having an inner diameter of 10 mm from one end. In addition, between the small-diameter portions 13, 13 formed at one or at equal intervals on the outer periphery of the main body 10, the distance between the upper ends of the slope portions 15 is about 25 mm, and Formed at an angle of about 45 degrees. The diameter of the nozzles 17 provided at equal intervals in the circumferential direction at the intermediate portion of the slope 15 is formed in a range of 0.4 to 2.0 mm, preferably 0.7 mm. Also, the number of nozzles may be a set of three on the left and right sides of the small diameter portion. That is, it is possible to provide 6 to 24 nozzles on the same circumference.
[ 0013]
When measured using a horn having an inner diameter of 135 mm, 150 mm, or 165 mm around the main body 10, 135 mm and 150 mm produced powder dry ice well, but in the case of 165 mm, the inner diameter was large. The production rate of the harmful powder dry ice varied due to too much. Also, as shown below, the peripheral wall around the main body 10 and the vacant space formed in the horn 21 also have optimum values.
When the distance between the peripheral wall surfaces in the case of the first chamber 25 and the second chamber 26 was around a horn diameter of 120 to 140 mm, the generation efficiency of the powder dry ice was highest.
In addition, the distance between the peripheral wall surfaces in the case of the first chamber 25, the second chamber 26, and the third chamber 27 was around the horn diameter of 140 to 170 mm, and the powder dry ice generation efficiency was highest.
Further, the distance between the peripheral wall surfaces in the case of the first chamber 25, the second chamber 26, the third chamber 27, and the fourth chamber 28 was about 150 to 200 mm in horn diameter, and the powder dry ice generation efficiency was the highest. .
[0014]
Next, the operation of this embodiment will be described. For example, the liquid temperature in a tank (not shown) filled with liquefied carbon dioxide gas at a pressure of 20 kg / cm 2 is −18 ° C. to −20 ° C. The gas vigorously ejected from the tank is supplied into the blind hole 11 of the main body 10 through a pipe (not shown) as shown by an arrow in FIG. A plurality of (eight in this embodiment) nozzles 17 provided at equal intervals in the radial direction on the inner wall surface of the blind hole 11 The inclined surface 15 is provided on both sides of the small-diameter portion 13. Here, the liquefied gas refers to liquefied nitrogen gas, liquefied oxygen gas, liquefied argon gas and the like.
[0015]
The gas released from the small-diameter nozzles 17 and 17 into the empty space 20 in the horn 21 is released into the horn 21 in a state of a primary pressure gradient, but the gas is adiabatically expanded. The temperature is lowered by abruptly expanding the volume, and disc-shaped pressure-barrier membranes 19, 19 are formed around each small-diameter portion 13, respectively. The disc-shaped pressure partition membrane 19 opens the horn 21 from the inside to the first chamber 25, the second chamber 26, and the third chamber 27 in the longitudinal direction of the main body 10 and further communicates with the opening 23. Although the chamber 28 is formed, the gas released from the nozzle 17 a located at the lower end of the main body 10 is first released to the atmosphere from the opening 23 of the open chamber 28. However, most of the other gas ejected from the nozzle 17 is ejected into the horn 21 defined by the pressure partition wall-like film 19, so that the gas is not directly emitted to the atmosphere side, and the third chamber 27 is not ejected. And then to the open chamber 28, or to the open chamber 28 after passing through the second and third chambers 26 and 27, and further through the first chamber 25, the second chamber 26 and the third chamber 27 Since the liquefied gas passes through each chamber and changes its pressure in several times to be ejected to the open chamber 28, the loss due to the pressure change is minimized, and the amount of liquefied gas such as dry ice powder is further improved. Can be.
[0016]
Experiments on the generation of powdered dry ice were carried out by changing the number of nozzles, the diameter of the nozzle, and the number of the small diameter portions, and the following results were obtained.
Experimental Example 1
Number of nozzles 1 set of 8 left and right 16 nozzle diameter 1.0mm
Number 8 on the same circumference Powder dry ice generation rate 41%
[0017]
The number, diameter, and number on the same circumference of the nozzle of Experimental Example 1 are not limited to the above, and the number of nozzles may be one set of three to twelve on the left and right. Further, the nozzle diameter is 0.4 to 2.0 mm, and it is also possible to provide 6 to 24 nozzles on the same circumference.
[0018]
Experimental example 2.
Nozzle number 2 sets of 8 left and right 32 nozzle diameter 0.8mm
Number 8 on the same circumference Powder dry ice generation efficiency 42%
[0019]
The number, diameter, and number on the same circumference of the nozzles in Experimental Example 2 are not limited to the above, and the number of nozzles may be one set of 3 to 12 nozzles on each side. Further, the nozzle diameter is 0.4 to 2.0 mm, and it is also possible to provide 6 to 24 nozzles on the same circumference.
[0020]
Experimental example 3.
Nozzle number 3 sets of 8 left and right 48 nozzle diameter 0.7mm
Number 8 on the same circumference Powder dry ice generation efficiency 43%
[0021]
The number, diameter, and number on the same circumference of the nozzle of the third embodiment are not limited to the above, and the number of nozzles may be one set of three to twelve on the left and right. Further, the nozzle diameter is 0.4 to 2.0 mm, and it is also possible to provide 6 to 24 nozzles on the same circumference.
[0022]
Experimental example 4.
Nozzle number 4 sets of 8 left and right 64 nozzle diameter 0.6mm
Number 8 on the same circumference Powder dry ice generation efficiency 44%
[0023]
The number, diameter, and number on the same circumference of the nozzle of the fourth embodiment are not limited to the above, and the number of nozzles may be one set of three to twelve on the left and right. The nozzle diameter is 0.4 to 2.0 mm, and 6 to 24 nozzles can be provided on the same circumference 2.
[0024]
Next, an experiment was conducted on the generation of a liquefied gas such as liquid nitrogen, argon, or oxygen, and the following results were obtained.
Experimental example 5 When small volumes of liquefied gas are continuously taken out (several tens of cc / min)
Number of nozzles One set of 4 left and right 8 nozzle diameter 0.6mm
Number 4 on the same circumference Generation efficiency 50-60%
There is no dent in the liquid surface when the distance between the nozzle and the liquid surface is 10 cm.
[0025]
The number, diameter, and number on the same circumference of the nozzles in Experimental Example 5 are not limited to the above, and the number of nozzles may be one set of three to eight on the left and right. The nozzle diameter is 0.4 to 1.0 mm, and 6 to 24 nozzles can be provided on the same circumference 2. Experimental Example 5 is an embodiment of the first aspect of the present invention, in which the number of the small-diameter portions 34 provided on the outer periphery of the main body 30 is one, and each of the small-diameter portions 34 faces the slope portions 35 provided on both sides of the small-diameter portion. It is provided with two nozzles 37 and is most suitable for continuously extracting liquefied gas at a flow rate of several tens of cc per minute. In this case, since there is only one small-diameter portion, the length is short, and handling is convenient because of the small size.
[0026]
Experimental example 6. When medium volume liquefied gas is continuously taken out (~ 3 / min)
The number of nozzles One set of 16 nozzles on each side, 8 nozzle diameters 1.0mm
Number 8 on the same circumference Generation efficiency 60-70%
There is no dent in the liquid surface when the distance between the nozzle and the liquid surface is 30 cm.
[0027]
The number, diameter, and number on the same circumference of the nozzle of Experimental Example 6 are not limited to the above, and the number of nozzles may be one set of three to twelve on the left and right. The nozzle diameter is 0.4 to 2.0 mm, and 6 to 24 nozzles can be provided on the same circumference 2.
[0028]
Experimental example 7. When a large volume of liquefied gas is continuously taken out (~ 20 / min)
Number of nozzles 4 sets of 8 nozzles on each side 64 nozzle diameter 1.0mm
Number 8 on the same circumference Generation efficiency 60-70%
There is no dent in the liquid surface when the distance between the nozzle and the liquid surface is 30 cm.
[0029]
The number, diameter, and number on the same circumference of the nozzle of Experimental Example 7 are not limited to the above, and the number of nozzles may be one set of three to twelve on the left and right. The nozzle diameter is 0.4 to 2.0 mm, and 6 to 24 nozzles can be provided on the same circumference 2.
[0030]
The experimental examples 6 and 7 relate to the embodiment of the second aspect of the present invention, in which the number of the small-diameter portions 13 provided on the outer periphery of the main body 10 is two or four, and the small-diameter portions 13 are provided on both sides of the small-diameter portion. The experiment was conducted in a case where 16 nozzles 17 were provided facing each other on the inclined surface 15 and a case where 64 nozzles 17 were provided. It is most suitable for taking out liquefied gas continuously. In this case, the length of the main body becomes longer because there are a plurality of small-diameter portions. However, since a plurality of vacancies can be formed in the horn, the pressure does not drop suddenly, and the pressure drops sequentially in several steps. Therefore, the production rate of dry ice powder is improved.
[0031]
【The invention's effect】
According to the first aspect of the present invention , a plurality of gases press-fitted into a blind hole provided in the main body are provided on an inner wall surface of the blind hole and open to an intermediate portion of a slope portion, and each slope portion has both ends of a small diameter portion. The inside of the horn is partitioned from the outside by a pressure-barrier-like film generated by collision of liquefied gas discharged from nozzles provided symmetrically in the circumferential direction continuously from the outside to prevent a sharp pressure drop. It improves the rate of production of powdered dry ice released into the atmosphere, and is particularly useful for continuous removal of small-volume powdered dry ice. Furthermore, the noise level can be considerably reduced by the pressure-septum-like membrane compared with the conventional one.
The invention according to claim 2 is a disk-shaped pressure partition membrane formed by impinging gas ejected from nozzles respectively formed on inclined surfaces provided on both sides of a plurality of small diameter parts formed outside the main body. A plurality of horns are formed in the horn to divide the inside of the horn into a plurality of sections, and the gas is released while passing through the partitioned chambers sequentially. The production amount of dry ice is further improved and the production rate is stabilized. In addition, the generated powder dry ice has uniformity, so that no clumps or the like are mixed therein, and further, the noise level can be considerably reduced by the pressure partition wall-like film as compared with the conventional one.
[Brief description of the drawings]
FIG. 1 is a front view showing a main part of a nozzle portion of a conventional dry ice manufacturing device.
FIG. 2 is a front view showing a main part of a nozzle in another conventional example.
FIG. 3 is a front view showing a main part of a nozzle showing still another conventional example.
FIG. 4 is a front view showing an embodiment of the invention of claim 2;
FIG. 5 is a sectional view taken along line AA of FIG. 4;
FIG. 6 is an enlarged sectional view of a nozzle portion.
FIG. 7 is a plan view of the main body showing the embodiment of the first invention.
FIG. 8 is a sectional view taken along line BB of FIG. 7;
FIG. 9 is a plan view showing a state in which the main body is attached to a horn.
FIG. 10 is a front view of a horn.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Main body 11 Blind hole 13 Small diameter section 15 Slope section 17 Nozzle 19 Pressure barrier membrane 20 Vacancy 21 Horn 23 Opening 30 Main body 32 Blind hole 34 Small diameter section 35 Slope section 37 Nozzle 41 Horn 45 Empty Chamber 46 opening

Claims (2)

A blind hole (32) is provided from one end inside the main body (30), and a 45-degree slope portion (35, 35) is continuously symmetrical on both sides of the small diameter portion (34) provided on the outer peripheral surface of the main body. A plurality of nozzles (37, 37) formed opposite to each other at right angles to each slope are provided at equal intervals in the circumferential direction, and a cylindrical horn (41) having an open end is provided. A space (45) is provided outside the main body and installed.
Opening collide at ambient pressure bulkhead-like film formed in the centrifugal direction (19), the lower end communicates with the atmosphere of the nozzle the small diameter portion of the gas ejected from the (37, 37) (34) facing (46 ) powder dry ice manufacturing apparatus characterized by preventing a rapid pressure drop is partitioned with the air provided within said horn having a. A plurality of small-diameter portions (13, 13) are provided at regular intervals on the outer peripheral surface of a main body (10) having a blind hole (11) therein, and a 45-degree slope portion is continuously provided on both sides of each small-diameter portion. (15, 15) are formed symmetrically facing each other, and a plurality of nozzles (17) provided orthogonally to the respective slopes are formed at equal intervals in pairs in the circumferential direction, and an opening ( A cylindrical horn (21) provided with ( 23) is provided with a space (20) provided outside the body (10),
A plurality of pressure partition-like membranes (19) formed in the centrifugal direction by impinging gas ejected from the opposed nozzles (17, 17) around the small diameter portions (13, 13) are provided in the horn. An apparatus for producing dry ice powder, wherein the apparatus is separated from the atmosphere to prevent a rapid pressure drop .

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