JP5922982B2 - Nozzle for dry ice injection and dry ice injection device - Google Patents

Description

  The present invention relates to a dry ice spray nozzle and a dry ice spray device.

  For example, a method called dry ice blasting (dry ice cleaning) is known as one method for removing deposits such as dirt attached to an object to be cleaned (see, for example, Patent Document 1). In this dry ice blast, particulate dry ice such as pellets or powder is sprayed at a high speed from the tip (jet outlet) of a nozzle together with a compressed gas such as compressed air and sprayed onto the surface of the object to be cleaned.

  Thereby, the deposits such as dirt attached to the cleaning target can be peeled and removed without damaging the surface of the cleaning target. Further, in this dry ice blasting, the dry ice itself is vaporized, so post-treatment after blasting is easy.

  Such a dry ice spraying apparatus for spraying dry ice is not only washed by the dry ice blast described above, but also, for example, for injection objects such as electrical / electronic parts and optical parts, processed parts thereof, for example, Widely used for various processes such as cleaning, deburring, and surface processing.

Utility Model Registration No. 2557383

  By the way, in the conventional dry ice jetting apparatus described above, in order to perform processing over as wide a range as possible with one nozzle scan, a jet nozzle having a substantially rectangular cross section with a jet port widened in the width direction is used. Yes.

  However, in the injection nozzle having such a wide shape, it is difficult to inject dry ice with a uniform pressure over the entire region of the injection port in the width direction. That is, in the conventional dry ice injection nozzle, when the dry ice is injected, sufficient acceleration energy cannot be given to the dry ice flowing through the nozzle by the compressed gas.

  For this reason, in the conventional dry ice injection device, dry ice cannot be injected at high speed over the entire width direction of the injection port, and there is a problem that sufficient processing cannot be performed on the injection target. It was.

  The present invention has been proposed in view of such conventional circumstances, and a dry ice spray nozzle and dry ice that can spray dry ice at a high speed over the entire width direction of the spout. It aims at providing an injection device.

（２） ドライアイスと圧縮ガスが混合される混合室と、
前記混合室にドライアイスを供給するドライアイス供給手段と、
前記混合室に圧縮ガスを供給する圧縮ガス供給手段と、
前記混合室から供給されたドライアイスを圧縮ガスと共に噴射するドライアイス噴射用ノズルとを備え、
前記ドライアイス噴射用ノズルが、前記（１）に記載のドライアイス噴射用ノズルであることを特徴とするドライアイス噴射装置。
（３） 前記ドライアイス噴射用ノズルは、ノズルガンを構成していることを特徴とする前記（２）に記載のドライアイス噴射装置。 In order to achieve the above object, the present invention provides the following means.
(1) A dry ice injection nozzle that forms a flow path in which dry ice is pumped together with a compressed gas, and injects dry ice from an outlet provided on the front end side of the flow path,
The spout has a substantially rectangular cross section, and the diameter gradually increases in the longitudinal direction of the spout from the smallest cross-sectional area in the flow path toward the spout, and the short end of the spout A pipe having a diameter that gradually decreases in the direction, and the flow path cross-sectional area of the pipe gradually increases from the minimum cross-sectional area toward the jet port ,
The pipe has a shape in which the diameter gradually decreases from the inlet provided on the base end side of the flow path toward the minimum cross-sectional area,
In the pipe, A _{1 is} a channel cross-sectional area at the minimum cross-sectional area, A _{2 is} a channel cross-sectional area at the jet port at the time of proper expansion, and A ₃ is a channel cross-sectional area at the jet port ,
When the pressure in the flow path at the inlet is p ₀ , the pressure in the flow path at the outlet is p, the Mach number at the outlet at the time of proper expansion is M, and the specific heat ratio of the compressed gas is k ,
The channel cross-sectional area A ₂ at the jet port at the proper expansion is obtained by calculating the Mach number M at the jet port at the proper expansion by the following formula (1), and the obtained value is substituted into the following formula (2). Is a value obtained by
The flow path cross-sectional area A ₃ on the spout, the nozzle for dry ice jet, characterized in that it is set to a value satisfying the relationship of the following formula (3).

( 2 ) a mixing chamber in which dry ice and compressed gas are mixed;
Dry ice supply means for supplying dry ice to the mixing chamber;
Compressed gas supply means for supplying compressed gas to the mixing chamber;
A dry ice injection nozzle for injecting dry ice supplied from the mixing chamber together with compressed gas;
The dry ice jetting device according to ( 1 ), wherein the dry ice jetting nozzle is the dry ice jetting nozzle.
( 3 ) The dry ice jetting apparatus according to ( 2 ), wherein the dry ice jetting nozzle constitutes a nozzle gun.

  As described above, according to the present invention, it is possible to provide a dry ice injection nozzle and a dry ice injection device that can inject dry ice at a high speed over the entire width direction of the outlet. is there.

It is a schematic diagram which shows an example of the dry ice injection apparatus to which this invention is applied. 1 shows a configuration example of a dry ice injection nozzle to which the present invention is applied, in which (a) is a front view thereof, (b) is a sectional view taken along line XX ′, and (c) is a sectional view taken along line YY ′. FIG. 4D is a sectional view taken along the line Z ₁ -Z ₁ ′, FIG. 4E is a sectional view taken along the line Z ₂ -Z ₂ ′, and FIG. 4F is a sectional view taken along the line Z ₃ -Z ₃ ′. The modification of the nozzle for dry ice injection to which this invention is applied is shown, (a) is the front view, (b) is the X-X 'sectional drawing. The size of each part of the nozzle for dry ice injection of Example 1, 2 is shown, (a) is the X-X 'sectional drawing, (b) is the Y-Y' sectional drawing. Shows the various dimensions of the nozzle for dry ice jet of Comparative Example 1, (a) is a front view thereof, (b), the X-X 'cross-sectional view, (c), the _Z 1 -Z _1' sectional FIG. 4D is a sectional view taken along the line Z ₂ -Z ₂ ′. Each part size of the nozzle for dry ice injection of comparative example 2 is shown, (a) is the front view, (b) is the XX 'sectional view, (c) is the YY' sectional view, (D) is the Z ₁ -Z ₁ ′ cross-sectional view, (e) is the Z ₂ -Z ₂ ′ cross-sectional view, (f) is the Z ₃ -Z ₃ ′ cross-sectional view, and (g) is It is the Z ₄ -Z ₄ ′ sectional view. Each part size of the nozzle for dry ice injection of comparative example 3 is shown, (a) is the front view, (b) is the XX 'sectional view, (c) is the YY' sectional view, (D) is the Z ₁ -Z ₁ ′ cross-sectional view, (e) is the Z ₂ -Z ₂ ′ cross-sectional view, (f) is the Z ₃ -Z ₃ ′ cross-sectional view, and (g) is It is the Z ₄ -Z ₄ ′ sectional view. It is a graph which shows the result of having calculated the speed of compressed gas about Examples 1 and 2 and Comparative Examples 1-3. It is a figure for demonstrating the test method which evaluates the injection ability of dry ice, (a) is sectional drawing along the longitudinal direction of a jet nozzle, (b) is a cross section along the transversal direction of a jet nozzle. FIG. It is a graph which shows the result of having measured the force which a pressure sensitive paper receives about Examples 1, 2 and Comparative Examples 1-3.

Hereinafter, a dry ice spray nozzle and a dry ice spray apparatus to which the present invention is applied will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent. In addition, the materials, dimensions, and the like exemplified in the following description are merely examples, and the present invention is not necessarily limited thereto, and can be appropriately modified and implemented without departing from the scope of the invention. .

(Dry ice spray device)
FIG. 1 is a schematic diagram showing an example of a dry ice spray apparatus 1 to which the present invention is applied.
As shown in FIG. 1, the dry ice jet apparatus 1 supplies a dry ice supply mechanism (dry ice supply means) 2 for supplying pellet-shaped dry ice (dry ice pellets) and compressed air (compressed gas). A compressed gas supply mechanism (compressed gas supply means) 3, a mixing chamber 4 for mixing dry ice and compressed air, and a nozzle gun (dry ice injection nozzle) 5 for injecting dry ice mixed with compressed air are roughly provided. ing.

  The dry ice supply mechanism 2 is assembled to the apparatus main body 1a and stores dry ice pellets (for example, a particle size of 3 mm) supplied from a dry ice pelletizer (dry ice pellet making machine) (not shown) in a cold state. A hopper 6 that carries the dry ice pellets out of the hopper 6, and dry ice pellets supplied by the feeder 7 are pulverized to dry powder (for example, a particle size of 0.5 mm or less) dry ice (dry ice powder) The dry ice powder is supplied to the mixing chamber 4.

  The compressed gas supply mechanism 3 includes a compressor 9 disposed outside the apparatus main body 1a. The compressor 9 compresses external air and then omits a very small amount of oil contained in the compressed air. The water is removed from the oil mist filter and the moisture in the compressed air is removed by a dryer (not shown), and then this clean compressed air is supplied to the mixing chamber 4 via the pressure regulating valve 10.

  The mixing chamber 4 is disposed inside the apparatus main body 1a, and mixes the dry ice powder supplied from the dry ice supply mechanism 2 and the compressed gas supplied from the compressed gas supply mechanism 3 to the nozzle gun 5. And supply.

  The nozzle gun 5 is connected to the mixing chamber 4 in the apparatus main body 1a via a hose 11, and by pulling the trigger 12, the dry ice powder supplied from the mixing chamber 4 is compressed with compressed air and the tip of the nozzle (jetting). Inject at high speed from the outlet 5a. Thereby, for example, it is possible to perform various processes such as cleaning, deburring, surface processing, and the like on an injection target such as an electrical / electronic component, an optical component, or a processed component thereof.

  In addition, the dry ice injection apparatus to which the present invention is applied is not necessarily limited to the configuration of the dry ice injection apparatus 1 shown in FIG. 1. For example, the dry ice pellets are compressed by omitting the pulverizer 8. The structure which injects with air may be sufficient.

  In addition, the dry ice injection device to which the present invention is applied, for example, after generating dry ice powder using liquefied carbon dioxide gas supplied from a liquefied carbon dioxide cylinder, using a dry ice injection nozzle such as a nozzle gun, This dry ice powder may be sprayed. In this case, nitrogen gas or the like supplied from a liquefied nitrogen gas cylinder can be used as the compressed gas.

  The dry ice spraying apparatus to which the present invention is applied is preferably used for dry ice blasting (dry ice cleaning) for removing deposits such as dirt attached to the object to be cleaned, but is not necessarily limited to such applications. However, the present invention can be used for various applications described above.

(Dry ice spray nozzle)
The nozzle gun 5 is composed of a dry ice spray nozzle to which the present invention is applied, and has a structure as shown in FIG. 2, for example.

2 shows a configuration example of a dry ice injection nozzle to which the present invention is applied. FIG. 2A is a front view seen from the jet outlet 21 side, and FIG. XX ′ sectional view along the direction X, (c) is a YY ′ sectional view along the short direction Y of the ejection port 21, and (d) is Z ₁ − at the ejection port 21. Z ₁ ′ sectional view, (e) is a Z ₂ -Z ₂ ′ sectional view at the smallest sectional area 22, and (f) is a Z ₃ -Z ₃ ′ sectional view at the introduction port 23.

  Specifically, the dry ice injection nozzles shown in FIGS. 2 (a) to 2 (f) form a flow path through which dry ice is pumped together with the compressed gas, and a jet outlet provided at the front end side of the flow path. 21, the dry ice is jetted, and the jet outlet 21 has a substantially rectangular cross section (in this example, a rectangle), and the cross sectional area minimum portion (referred to as a throat) 22 in the flow path is connected to the jet outlet 21. On the other hand, there is provided a pipe line 20 whose diameter gradually increases in the longitudinal direction X of the ejection port 21 and whose diameter gradually decreases in the lateral direction Y of the ejection port 21. In addition, the flow path cross-sectional area of the pipe line 20 gradually increases from the cross-sectional area minimum portion 22 toward the ejection port 21.

  In the present invention, the cross-sectional shape along the longitudinal direction X of the jet port 21 of the pipe line 20 gradually increases in diameter from the cross-sectional area minimum portion 22 toward the jet port 21, thereby widening the dry ice jet nozzle. It is possible to eject the dry ice over a wide range as much as possible with a single nozzle scan.

  On the other hand, in the present invention, the cross-sectional shape along the short direction Y of the spout 21 of the pipe line 20 is gradually reduced in diameter from the cross-sectional area minimum portion 22 toward the spout 21. It is possible to spray dry ice with a uniform pressure over the entire area in the longitudinal direction (width direction) X.

  Further, the pipe line 20 has a shape in which the diameter gradually decreases from the introduction port 23 provided on the base end side toward the cross-sectional area minimum portion 22, so that in the cross section along the longitudinal direction X of the jet port 21. The channel has a so-called medium nozzle (Laval nozzle) structure in which the channel is narrowed in the middle.

  Thereby, sufficient acceleration energy can be given to the dry ice flowing in the pipe line 20 by the compressed gas, and the dry ice is jetted at a high speed over the entire area in the longitudinal direction (width direction) X of the ejection port 21. It is possible.

  The pipe 20 has a structure that is divided into an outlet side pipe 20A and an inlet side pipe 20B with the cross-sectional area minimum portion 22 interposed therebetween. And the outlet side pipe line 20A gradually increases in diameter in the cross section along the longitudinal direction X of the jet port 21 from the cross-sectional area minimum portion 22 having a circular cross section toward the jet port 21 having a rectangular cross section, and While the outlet side channel 20a whose diameter is gradually reduced in the cross section along the short direction Y of the jet port 21 is formed, the inlet side channel 20B has a circular sectional shape with a minimum sectional area from the circular inlet port 23. In the section along the longitudinal direction X and the short direction Y of the jet port 21 toward the portion 22, an inlet-side flow path 20 b is formed in which the diameter gradually decreases.

  Further, the outlet side pipe line 20A is provided with a rectifying path 24 for rectifying the flow of the dry ice jetted from the jet outlet 21. The rectifying passage 24 has the same cross-sectional shape (rectangular cross-sectional shape) as the ejection port 21, and is provided extending from the ejection port 21 in the axial direction Z.

  On the other hand, the inlet side pipe 20B is provided with an introduction path 25 for introducing the dry ice supplied from the mixing chamber 4 into the introduction port 23 together with the compressed gas. The introduction path 25 has the same cross-sectional shape (cross-sectional circular shape) as the introduction port 23, and is provided extending from the introduction port 23 in the axial direction Z.

In the present invention, in the pipe line 20, the channel cross-sectional area at the minimum cross-sectional area portion 22 is A ₁ , the channel cross-sectional area at the ejection port 21 at the time of proper expansion is A ₂ , and the channel breakage at the ejection port 21 is the area and a _3, p ₀ in the flow path pressure at inlet _23, p in the flow path pressure at spout 21, the Mach number in the spout 21 when appropriate expansion M, specific heat ratio of compressed gas , K is the Mach number M at the jet outlet at the time of proper expansion by the following formula (1), and then substituting this calculated value into the following formula (2), the jet at the time of proper expansion determining a flow path cross-sectional area _{a 2} at the outlet 21. In this case, the flow path cross-sectional area A ₃ on the spout 21, it is necessary to set to a value satisfying the relationship of the following formula (3).

That is, the above expressions (1) and (2) are conditional expressions for obtaining an optimal expansion jet of dry ice while preventing the generation of unnecessary shock waves, and the flow path pressure p ₀ at the inlet 23 is If there is a sufficient pressure difference between the pressures p in the flow path at the jet port 21, the compressed gas is accelerated from the inlet port 23 to the jet port 21, and the Mach number M becomes 1 or more.

  At this time, when the above formulas (1) and (2) are satisfied, it is possible to obtain an optimal expansion jet of dry ice while preventing shock waves from being generated inside the pipe line 20 or in the vicinity of the jet port 21. It is.

The above formula (3) is a conditional formula for exerting the function as an injection nozzle to which the present invention is applied, and satisfies the relationship of the above formula (3), that is, the above formulas (1), ( than the flow path cross-sectional area a ₂ in ejecting port 21 at the proper inflated determined by 2), the flow path cross-sectional area a ₃ on the spout 21 to increase (a 2 _{<a 3)} that is, the dry ice It is possible to obtain an optimal expansion jet.

On the other hand, when the above equation (3) is not satisfied, that is, when A ₂ ≧ A ₃ , the expansion of the compressed gas is insufficient, and the compressed gas is accelerated over the entire length direction (width direction) X. Can not be. As a result, it becomes difficult to increase the speed of dry ice ejected from the ejection port 21.

  That is, in this dry ice injection nozzle, the speed (flow velocity) of dry ice can be increased following the flow of the compressed gas as the velocity (flow velocity) of the compressed gas flowing in the pipe line 20 increases. And the higher the speed of the dry ice ejected from the ejection port 21, the greater the energy when the dry ice collides with the ejected object, so that it is possible to efficiently perform the processing such as cleaning.

  On the other hand, if the flow path cross-sectional area of the pipe line 20 does not gradually increase from the cross-sectional area minimum portion 22 toward the jet port 21 and the flow path cross-sectional area increases in the middle, the expansion of the compressed gas is insufficient. Therefore, the compressed gas cannot be accelerated over the entire length direction (width direction) X. As a result, it becomes difficult to increase the speed of dry ice ejected from the ejection port 21.

When the flow path cross-sectional area A ₃ at the jet outlet 21 is smaller than the flow path cross-sectional area A ₁ at the minimum cross-sectional area portion 22 (A ₃ <A ₁ ), the compressed gas chokes at the jet outlet 21. Therefore, this compressed gas cannot be accelerated over the entire region in the longitudinal direction (width direction) X.

  As described above, according to the present invention, a dry ice spray nozzle capable of spraying dry ice at a high speed over the entire region in the width direction X of the spout 21, and such a dry ice spray nozzle. It is possible to provide a dry ice spraying device including

In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the present invention, as shown in FIGS. 3A and 3B, a plurality of the dry ice injection nozzles (pipe lines 20) are arranged in the longitudinal direction (width direction) X of the injection port 21. Alternatively, they can be used in combination. In this case, it is possible to expand the range that can be processed by one nozzle scan. Further, in the longitudinal direction (width direction) X of the jet outlet 21, even if the rectifying path 24 is connected (overlapped) between the jet outlets 21 of the adjacent pipe lines 20, one rectifying path 24 is formed. Good.

  Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

  In this example, first, dry ice acceleration of the dry ice injection nozzles (Examples 1 and 2) of the present invention and the dry ice injection nozzles of the comparative examples (Comparative Examples 1, 2 and 3) by computer simulation. Performance evaluation was performed.

Example 1
The nozzle for dry ice injection of Example 1 is provided with the pipe line 20 shown in FIG. 2, and the dimensions of each part of the nozzle for dry ice injection (pipe line 20) of Example 1 are shown in FIG. It is as follows.

That is, in the nozzle for dry ice injection of Example 1 (line 20), 14 mm caliber _{D 1} of the inlet 23, the diameter _{D 2} of the cross-sectional area smallest unit 22 5 mm.phi, width W and height of the spout 21 H was 40 mm × 1.2 mm, the length L ₁ of the inlet-side channel 20 b was 20 mm, the length L ₂ of the outlet-side channel 20 a was 99.6 mm, and the length L ₃ of the rectifying channel 24 was 10 mm. Further, the material of the outlet side pipe line 20A and the inlet side pipe line 20B was SUS304.

Further, when the compressed gas is air (specific heat ratio k = 1.4), the pressure in the mixing chamber 4 is 0.4 MPaG, the temperature is 0 ° C., and dry ice is injected into a normal pressure atmosphere, the inlet 23 The pressure p ₀ in the flow path at is 0.5013 MPa, and the pressure p in the flow path at the outlet 21 is 0.1013 MPa.

Then, when these values are substituted into the above equation (1), the Mach number M at the ejection port 21 at the time of the appropriate expansion is 1.702. Further, when this value is substituted into the above equation (2), the ratio (A ₂ / A) of the flow path cross-sectional area A ₂ at the jet outlet during the appropriate expansion and the flow path cross-sectional area A ₁ at the minimum cross-sectional area portion. ₁ ) is 1.34. Therefore, the value of A ₃ / A ₂ is 1.83, and in Example 1, the relationship of the above formula (3) is satisfied.

(Example 2)
The nozzle for dry ice injection of Example 2 is provided with the pipe line 20 shown in FIG. 2, and the dimensions of each part of the nozzle for dry ice injection (pipe line 20) of Example 2 are shown in FIG. Of the dimensions shown, the same as Example 1 except that the width W and height H of the jet port 21 are set to 40 mm × 0.66 mm. In this case, the value of A ₃ / A ₂ is 1.0.

(Comparative Example 1)
The dry ice injection nozzle of Comparative Example 1 is provided with a pipe line 20 as shown in FIGS.
5 shows the configuration of the dry ice jet nozzle of Comparative Example 1, (a) is a front view seen from the jet port 21 side, and (b) is XX ′ of the jet port 21. FIG. A sectional view, (c) is a Z ₁ -Z ₁ ′ sectional view at the smallest sectional area 22, and (d) is a Z ₂ -Z ₂ ′ sectional view at the inlet 23.
Further, in the pipeline 20 shown in FIGS. 5 (a) to 5 (d), portions equivalent to those in the pipeline 20 shown in FIGS. Shall be omitted.

  The pipe line 20 has an outlet-side flow path 20a having the same diameter from the cross-sectional area minimum portion 22 having a circular cross section toward the jet port 21 having a circular cross section. Other than that, it has the structure fundamentally the same as the pipe line 20 shown in the said FIG.

And the size of each part of the nozzle (pipe 20) for dry ice injection of this comparative example 1 is as showing in FIG.5 (b). That is, in the nozzle for dry ice injection of the comparative example 1 (line 20), 14 mm caliber _{D 1} of the inlet 23, spout 21 and the diameter _{D 2} of the cross-sectional area smallest unit 22 5 mm.phi, the inlet channel 20b of 20mm length _{L 1,} the exit-side flow path 20a of the length _{L 2} was 99.6Mm. Further, the material of the outlet side pipe line 20A and the inlet side pipe line 20B was SUS304.

(Comparative Example 2)
The dry ice injection nozzle of Comparative Example 2 is provided with a pipe line 60 as shown in FIGS.
6 shows the configuration of the dry ice jet nozzle of Comparative Example 2, (a) is a front view seen from the jet port 21 side, and (b) is in the longitudinal direction X of the jet port 21. FIG. along the X-X 'cross-sectional view, (c) is, Y-Y along the lateral direction Y of the spout 21' sectional view, (d) is, _Z 1 -Z ₁ at the spout 21 ' (E) is a Z ₂ -Z ₂ ′ sectional view at the enlarged diameter portion 26, (f) is a Z ₃ -Z ₃ ′ sectional view at the smallest sectional area 22, and (g) is FIG. ₄ is a Z ₄ -Z ₄ ′ cross-sectional view at the introduction port 23.
In addition, in the pipeline 60 shown in FIGS. 6A to 6G, the same names and symbols are assigned to the same parts as the pipeline 20 shown in FIGS. Shall be omitted.

  The pipe 60 gradually increases in diameter in the cross section along the longitudinal direction X of the jet port 21 from the cross-sectional area minimum portion 22 having a circular cross section toward the jet port 21 having a rectangular cross section. After the diameter gradually increases in the cross section along the short direction Y, the outlet channel 20a gradually decreases in diameter. That is, the outlet-side channel 20 a has a diameter-expanding portion 26 in the middle of the axial direction Z in the cross-section along the short direction Y of the spout 21, and the spout 21 from the diameter-expanded portion 26. And the diameter gradually decreases toward the enlarged diameter portion 26 from the cross-sectional area minimum portion 22. Other than that, it has the structure fundamentally the same as the pipe line 20 shown in the said FIG.

And the size of each part of the nozzle (pipe 60) for this dry ice injection of the comparative example 2 is as showing in FIG.6 (b), (c). That is, in the nozzle for dry ice injection of the comparative example 2 (line 60), the diameter _{D 1} of the inlet 23 14 mm, the diameter _{D 2} of the cross-sectional area smallest unit 22 5 mm.phi, width _{W 1} and a height of spout 21 is 40 mm × 1.2 mm and _{H 1,} 13 mm × 6.0 mm width _{W 2} and a height _{H 2} of the enlarged diameter portion 26, the inlet channel 20b 20 mm length _{L 1} of, the exit-side flow path 20a length The length L ₂ was 99.6 mm, the length L ₃ of the rectifying path 24 was 10 mm, and the length L ₄ from the cross-sectional area minimum portion 22 to the enlarged diameter portion 26 was 30 mm. Further, the material of the outlet side pipe line 20A and the inlet side pipe line 20B was SUS304.

(Comparative Example 3)
The dry ice injection nozzle of Comparative Example 3 is provided with a pipe line 80 as shown in FIGS.
7 shows the dimensions of each part of the dry ice jet nozzle of Comparative Example 3, (a) is a front view seen from the jet port 21 side, and (b) is the longitudinal direction X of the jet port 21. FIG. XX ′ cross-sectional view taken along the line, (c) is a YY ′ cross-sectional view taken along the short direction Y of the spout 21, and (d) is Z ₁ -Z ₁ at the spout 21. 'Cross sectional view, (e) is a Z ₂ -Z ₂ ' sectional view at the enlarged diameter portion 26, (f) is a Z ₃ -Z ₃ 'sectional view at the smallest sectional area portion 22 (g) is _Z 4 -Z ₄ 'sectional view at the inlet 23.

  The pipe 80 gradually decreases in diameter after the diameter gradually increases in the cross section along the longitudinal direction X of the jet port 21 from the circular cross-sectional area minimum portion 22 toward the jet port 21 having a rectangular cross section. In addition, an outlet-side flow path 20a whose diameter gradually decreases in the cross section along the short direction Y of the ejection port 21 is provided. That is, the outlet-side flow path 20 a has a diameter-expanding portion 26 in the middle of the axial direction Z in the cross section along the longitudinal direction X of the spout 21, and from the diameter-expanded portion 26 to the spout 21. The shape has a shape in which the diameter gradually decreases and the diameter gradually increases from the cross-sectional area minimum portion 22 toward the enlarged diameter portion 26. Other than that, it has the structure fundamentally the same as the pipe line 20 shown in the said FIG.

And the size of each part of the nozzle (pipe line 80) for dry ice injection of this comparative example 3 is as showing in FIG.7 (b), (c). That is, in the nozzle for dry ice jet of Comparative Example 3 (pipe 80), the diameter _{D 1} of the inlet 23 14 mm, the diameter _{D 2} of the cross-sectional area smallest unit 22 5 mm.phi, width _{W 1} and a height of spout 21 The length H ₁ is 40 mm × 1.2 mm, the width W ₂ and the height H ₂ of the enlarged diameter portion 26 are 45 mm × 3.8 mm, the length L ₁ of the inlet-side flow path 20b is 20 mm, and the length of the outlet-side flow path 20a The length L ₂ was 99.6 mm, the length L ₃ of the rectifying path 24 was 10 mm, and the length L ₄ from the cross-sectional area minimum portion 22 to the enlarged diameter portion 26 was 30 mm. Further, the material of the outlet side pipe line 20A and the inlet side pipe line 20B was SUS304.

  And about the dry ice injection nozzle of these Examples 1 and 2 and Comparative Examples 1-3, the flow of the compressed gas was calculated by computer simulation, and the speed of the compressed gas in the injection nozzle was calculated. In the computer simulation, the pressure in the mixing chamber 4 was set to 0.4 MPaG, the temperature was set to 0 ° C., the pressure at a position far from the jet port was set to 0 MPaG, and the temperature was set to 0 ° C. The simulation result is shown in FIG.

  As shown in FIG. 8, the dry ice injection nozzle of Example 1 has a faster compressed gas speed than the dry ice injection nozzles of Comparative Examples 1 to 3, and has excellent acceleration performance. I understand that. In particular, the dry ice injection nozzle of Example 1 has a compressed gas speed three times or more faster than the dry ice injection nozzles of Comparative Examples 2 and 3.

  In the dry ice injection nozzle, the higher the speed (flow velocity) of the compressed gas flowing in the flow path, the higher the speed (flow velocity) of the dry ice can follow the flow of the compressed gas. And the higher the speed of the dry ice sprayed from the jet nozzle 21, the larger the energy when the dry ice collides with the jetting object, so that it is possible to efficiently perform processing such as cleaning.

On the other hand, it can be seen that the dry ice injection nozzle of Example 2 is slower than the dry ice injection nozzle of Example 1 although the speed of the compressed gas is faster than the dry ice injection nozzles of Comparative Examples 2 and 3. Therefore, in order to increase the speed of the compressed gas, it is desirable to set the value of A ₃ / A _{2 to} a value larger than 1.0.

  Next, as shown in FIG. 9, the dry ice spray nozzles (Examples 1 and 2) of the present invention and the dry ice spray nozzles of the comparative examples (Comparative Examples 1 to 3) are connected to the nozzles 21 as shown in FIG. While the sprayed dry ice DI collided with the pressure sensitive paper P, the pressure sensitive paper P was moved at a constant speed in the short side direction Y of the jet outlet 21, and the force received by the pressure sensitive paper P at this time was measured.

  Specifically, for the dry ice injection nozzles of Examples 1 and 2 and Comparative Examples 1 to 3, the compressed gas is air, the pressure in the mixing chamber 4 is 0.4 MPaG, the temperature is 0 ° C. The test was carried out with the supply rate of ice DI being 20 kg / h, the distance from the jet outlet 21 to the pressure sensitive paper P being 30 mm, and the feeding speed of the pressure sensitive paper P being 150 mm / s.

  The test results are shown in FIG. In FIG. 10, the maximum value of the force received by the pressure sensitive paper P is set to 1, and the ratio is displayed as the pressure distribution in the longitudinal direction X of the jet port 21.

  As shown in FIG. 10, the dry ice spray nozzle of Example 1 has a larger force that the pressure sensitive paper P receives over the entire region in the width direction than the dry ice spray nozzles of Comparative Examples 1 to 3, and has a processing capability. I understand that it is expensive.

On the other hand, the pressure applied to the dry ice jet nozzle of Example 2 is higher than that of the dry ice jet nozzles of Comparative Examples 2 and 3, but the pressure sensitive paper P is higher than that of the dry ice jet nozzle of Example 1. It can be seen that the force received by is small. Therefore, in order to increase the processing capability, it is desirable to set the value of A ₃ / A _{2 to} a value larger than 1.0.

  On the other hand, as shown in FIGS. 8 and 10, the dry ice injection nozzle of Comparative Example 1 has a higher compressed gas speed than the dry ice injection nozzle of Example 2, but the dry ice injection of Example 2 It can be seen that the region in the width direction in which the force received by the pressure sensitive paper P is larger than that of the nozzle for use is extremely narrow. Therefore, in the dry ice injection nozzle of Comparative Example 1, the range that can be processed by one nozzle scan is limited.

The nozzle for dry ice jet of Example 1 and Comparative Example 2, although the flow path cross-sectional area A ₃ on the spout 21 is the same, an air flow injected from the nozzle for dry ice jet of Example 1 It was less than the dry ice jet nozzle of Comparative Example 2, and was about 77% with respect to the dry ice jet nozzle of Comparative Example 2.

  Therefore, when the dry ice injection nozzle of the first embodiment is used, the amount of compressed gas used can be reduced, so that the compressed gas supply capacity and the like by the compressor 9 can be lowered as compared with the prior art. It is possible to reduce running costs such as.

DESCRIPTION OF SYMBOLS 1 ... Dry ice injection apparatus 2 ... Dry ice supply mechanism (dry ice supply means) 3 ... Compressed gas supply mechanism (compressed gas supply means) 4 ... Mixing chamber 5 ... Nozzle gun (nozzle for dry ice injection) 5a ... Outlet 20 ... Pipe line 20A ... Exit side pipe line 20B ... Inlet side pipe line 20a ... Outlet side flow path 20b ... Inlet side flow path 21 ... Ejection port 22 ... Minimum cross-sectional area 23 ... Inlet port 24 ... Rectifier path 25 ... Introduction path

Claims (3)

A dry ice injection nozzle that forms a flow path in which dry ice is pumped together with a compressed gas, and injects dry ice from an outlet provided on the front end side of the flow path,
The spout has a substantially rectangular cross section, and the diameter gradually increases in the longitudinal direction of the spout from the smallest cross-sectional area in the flow path toward the spout, and the short end of the spout A pipe having a diameter that gradually decreases in the direction, and the flow path cross-sectional area of the pipe gradually increases from the minimum cross-sectional area toward the jet port ,
The pipe has a shape in which the diameter gradually decreases from the inlet provided on the base end side of the flow path toward the minimum cross-sectional area,
In the pipe, A _{1 is} a channel cross-sectional area at the minimum cross-sectional area, A _{2 is} a channel cross-sectional area at the jet port at the time of proper expansion, and A ₃ is a channel cross-sectional area at the jet port ,
When the pressure in the flow path at the inlet is p ₀ , the pressure in the flow path at the outlet is p, the Mach number at the outlet at the time of proper expansion is M, and the specific heat ratio of the compressed gas is k ,
The channel cross-sectional area A ₂ at the jet port at the proper expansion is obtained by calculating the Mach number M at the jet port at the proper expansion by the following formula (1), and the obtained value is substituted into the following formula (2). Is a value obtained by
The flow path cross-sectional area A ₃ on the spout, the nozzle for dry ice jet, characterized in that it is set to a value satisfying the relationship of the following formula (3).

A nozzle for dry ice injection that injects dry ice together with compressed gas;
A mixing chamber in which the dry ice and the compressed gas are mixed;
Dry ice supply means for supplying dry ice to the mixing chamber;
A compressed gas supply means for supplying compressed gas to the mixing chamber;
The dry ice spraying device according to claim 1, wherein the dry ice spraying nozzle is the dry ice spraying nozzle according to claim 1 . The dry ice jetting apparatus according to claim 2 , wherein the dry ice jetting nozzle constitutes a nozzle gun.

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