JP2016138685A - Cryogenic liquid gas injection state adjustment method and cryogenic liquid gas injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable liquefied nitrogen injected from a device to be easily adjusted to strike against a cooled object under its mist state even if a required injection flow rate of the liquefied nitrogen is determined in advance.SOLUTION: This invention relates to an adjustment method performed by using a liquefied nitrogen injection device 1 having removably installed injection pipe 2 for injecting liquefied nitrogen. The liquefied nitrogen is injected by the injection device 1 continuously from the injection pipe 2 for a predetermined time, and upon elapsing the predetermined time, if the liquefied nitrogen being injected from the injection pipe 2 is kept in liquid state at a position of a cooled object 29, the injection pipe 2 is replaced with another injection pipe longer than the former. In turn, when the liquefied nitrogen being injected from the injection pipe 2 is gasified after elapsing the predetermined time and does not reach the position of the cooled object 29, the injection pipe is replaced with another injection pipe shorter than the former.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for adjusting an injection state of a low-temperature liquefied gas in an apparatus for injecting a low-temperature liquefied gas such as liquefied nitrogen to an object to be cooled.

  Conventionally, in the production process of frozen foods such as ice cream and shaved ice, liquefied nitrogen is sprayed onto frozen foods to freeze or cool them. An apparatus for injecting liquefied nitrogen to an object to be cooled in this way is disclosed in Patent Document 1, for example. The liquefied nitrogen injection device disclosed in this document has been developed by the present applicant.

JP 2008-145028 A

  In order to efficiently cool the object to be cooled by injecting liquefied nitrogen to the object to be cooled, it is necessary to cause the mist of liquid nitrogen to collide with the object to be cooled. That is, when mist-like liquefied nitrogen collides with an object to be cooled, the cooling effect by latent heat increases.

  By the way, if the temperature of liquefied nitrogen injected from the injection port of the apparatus is too low or the injection flow rate is too high, the injected liquefied nitrogen does not become a mist state until it collides with the object to be cooled, and the liquid state ( Or, it collides with an object to be cooled in a high liquid ratio). In this case, the liquefied nitrogen that has collided with the object to be cooled turns into a spherical shape and falls down without substantially exchanging heat with the object to be cooled. Moreover, if a to-be-cooled object is easy to destroy a shape like soft cream, there exists a possibility that the shape may be destroyed by colliding with a to-be-cooled object with a liquid. On the other hand, if the temperature of the liquefied nitrogen injected from the injection port of the apparatus is too high or the injection flow rate is low, the liquefied nitrogen is vaporized early after injection and the object to be cooled cannot be cooled.

  Therefore, it is desirable to adjust so that the liquefied nitrogen injected from the injection port of the apparatus is in a mist state immediately before colliding with the object to be cooled, but the state of liquefied nitrogen injected from the injection port of the apparatus is the injection flow rate. Depending on the temperature of the piping supplying liquefied nitrogen, the outside air temperature, etc., it was not easy to reliably create such a mist state. Of course, if the injection flow rate is adjusted by valve operation, it is possible to make the liquefied nitrogen injected from the injection port into a mist state just before colliding with the object to be cooled, but the required injection flow rate is determined in advance. In some cases, it is difficult to create a mist state by such adjustment.

  The present invention was devised in view of the above problems, and even when the required injection flow rate is determined in advance, the low-temperature liquefied gas injected from the apparatus is to be cooled. It is an object of the present invention to provide an adjustment method and apparatus that can be easily adjusted so as to collide in a mist state.

  The method for adjusting the injection state of the low-temperature liquefied gas according to the present invention is premised on using a low-temperature liquefied gas injection device that is detachably provided with an injection pipe for injecting the low-temperature liquefied gas. Specifically, the low-temperature liquefied gas injection device continuously injects the low-temperature liquefied gas from the injection pipe for a predetermined time, and after the predetermined time has elapsed, the low-temperature liquefied gas injected from the injection pipe becomes the position of the object to be cooled. When the liquid is in the liquid state, the injection pipe is replaced with a longer one. On the other hand, when the low-temperature liquefied gas injected from the injection pipe evaporates and does not reach the position of the object to be cooled after the predetermined time has elapsed, the injection pipe is replaced with a shorter one.

  According to the method of adjusting the injection state of the low-temperature liquefied gas having the above-described configuration, preparing various types of replacement injection pipes having different lengths, and continuously injecting liquefied nitrogen from the injection pipe for a predetermined time; By alternately repeating the operation of exchanging the injection pipe, the injection state can be easily set to the optimum state, and the cooling efficiency of the object to be cooled can be improved.

  The method for adjusting the injection state of the low-temperature liquefied gas according to the present invention is based on the premise that the low-temperature liquefied gas injection device including the injection pipe unit including a plurality of injection pipes of the same length for injecting the low-temperature liquefied gas is detachable And Specifically, the low-temperature liquefied gas injection device continuously injects low-temperature liquefied gas from a plurality of injection pipes for a predetermined time, and after the predetermined time has elapsed, the low-temperature liquefied gas injected from the injection pipe is cooled. When the liquid pipe is in the liquid state, the injection pipe unit is replaced with one having a longer injection pipe. On the other hand, when the low-temperature liquefied gas injected from the injection pipe is vaporized and does not reach the position of the object to be cooled after the predetermined time has elapsed, the injection pipe unit is replaced with one having a shorter injection pipe. .

  According to the method for adjusting the injection state of the low-temperature liquefied gas having the above-described configuration, a large number of replacement injection pipe units having injection pipes having different lengths are prepared, and liquefied nitrogen is supplied from the injection pipe for a predetermined time. By alternately repeating the operation of continuously injecting and the operation of replacing the injection pipe unit, the injection state can be easily set to the optimum state, and the cooling efficiency of the object to be cooled can be improved.

  In the method for adjusting the injection state of the low-temperature liquefied gas having the above-described configuration, the injection pipe unit includes, for example, a main pipe having a connection portion connected to a low-temperature liquefied gas supply portion at a base end portion, and a base pipe And a plurality of injection pipes of the same length to which ends are connected.

  The low temperature liquefied gas injection device of the present invention is detachably provided with an injection pipe unit including a plurality of injection pipes of the same length for injecting a low temperature liquefied gas, and the injection pipe unit is provided at a base end portion. The main pipe having a connection part connected to the supply part of the low-temperature liquefied gas and a plurality of injection pipes having the same length and having the base end part connected to the main pipe may be included.

  According to the present invention, even when the required injection flow rate is determined in advance, the low-temperature liquefied gas injected from the apparatus can be adjusted to collide with the object to be cooled in a mist state. It becomes easy.

(A) is a front view of an injection pipe unit or the like of an injection device for liquefied nitrogen. (B) is a side view of an injection pipe unit and the like of the liquefied nitrogen injection device. It is a piping flow figure of a liquefied nitrogen supply device. It is a procedure figure for explaining exchange work of an injection pipe unit. It is a figure which shows the deformation | transformation embodiment of an injection pipe. However, illustration of some injection pipes is omitted.

  Hereinafter, a low temperature liquefied gas injection device and a method of adjusting a low temperature liquefied gas injection state according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, liquefied nitrogen will be described as an example of a low-temperature liquefied gas.

  As shown in FIGS. 1 and 2, the liquefied nitrogen injection device 1 includes an injection pipe 2, a main pipe 3, a connection portion 4, a liquefied nitrogen supply pipe 6, a liquefied nitrogen supply device 7, and the like.

  The injection pipe 2 is a pipe for injecting liquefied nitrogen. In this embodiment, the injection pipe 2 has the same length, the same inner and outer diameter (for example, inner diameter 0.4 mm, outer diameter 1.6 mm), and the same material (for example, stainless steel). Multiple (8) sets. The plurality of injection pipes 2 are arranged at a predetermined interval from each other. The injection pipe 2 has a base end connected to the main pipe 3 by brazing or the like, and liquefied nitrogen is supplied to the inside through the main pipe 3. In the example shown in FIG. 1, the base end portions of the plurality of injection pipes 2 are connected to the side surfaces of the main pipe 3 at equal intervals in the circumferential direction.

  The basic pipe 3 has a connecting portion 4 for connecting to the liquefied nitrogen supply pipe 6 at the base end thereof, and liquefied nitrogen is supplied into the basic pipe 3 through the liquefied nitrogen supply pipe 6. For example, a pipe joint is employed as the connecting portion 4. The main pipe 3 and the injection pipe 2 constitute an injection pipe unit 8 that can be attached to and detached from the liquefied nitrogen supply pipe 6. In addition, the front-end | tip part of the basic pipe 3 is obstruct | occluded.

  The liquefied nitrogen supply pipe 6 receives supply of liquefied nitrogen from the liquefied nitrogen supply device 7 and supplies liquefied nitrogen to the injection pipe unit 8.

  As shown in FIG. 2, the liquefied nitrogen supply device 7 is a valve for controlling the flow rate and pressure of liquefied nitrogen supplied to the LGC (ultra low temperature container) 11 filled with liquefied nitrogen, the gas-liquid separator 12, and the injection pipe 2. 13, 14, subcooler 15, control unit 21, and the like.

  The LGC 11 is filled with liquefied nitrogen at a pressure of about 600 kPa, and the internal liquefied nitrogen is supplied to the subcooler 15 via the pipe 16. The pipe 16 is covered with a heat insulating material 17.

  In the subcooler 15, one of the pipes 18 branched from the pipe 16 is further branched into a pipe 18 a and a pipe 18 b, and from either of the pipes 18 a and 18 b to the liquefied nitrogen reservoir 19 through the gas-liquid separator 12. Liquefied nitrogen is supplied. An electromagnetic valve 23 that opens and closes in accordance with a command from the control unit 21 is provided in the middle of each of the pipes 18a and 18b. Further, a liquid level sensor 24 for detecting the liquid level of the stored liquefied nitrogen is provided in the liquefied nitrogen reservoir 19, and the control unit 21 obtains liquid level height information obtained from the liquid level sensor 24. Based on the above, the opening and closing of the electromagnetic valve 23 is controlled to maintain the liquid level in the liquefied nitrogen reservoir 19 within a certain range. The nitrogen vaporized in the liquefied nitrogen reservoir 19 is exhausted from the exhaust gas pipe 26 to the outside.

  The other pipe 27 branched in two from the pipe 16 passes through the liquefied nitrogen at −196 ° C. stored in the liquefied nitrogen reservoir 19 and is led out from the subcooler 15, via the valve 14 and the flexible hose 27. And connected to another liquefied nitrogen reservoir 28. The liquefied nitrogen is once stored in the liquefied nitrogen storage section 28 and then supplied to each injection pipe unit 8 via the valve 13 (flow control valve such as a needle valve). In the example shown in FIG. 2, the injection pipe units 8 are provided at five locations, and the flow rate of liquefied nitrogen supplied to each injection pipe unit 8 can be adjusted by a valve 13 provided separately. ing.

  A temperature detector T1 is provided for detecting the temperature in the vicinity of the connection portion of the injection pipe 2 with respect to the main pipe 3, and a temperature detector T2 is provided for detecting the temperature of the liquefied nitrogen supply pipe 6. ing. The positions where these temperature detectors T1 and T2 detect the temperature are about 100 mm apart in the linear direction.

  In the liquefied nitrogen supply device 7, the subcooler 15 is provided as described above, so that the liquefied nitrogen in the pipe is supercooled to prevent vaporization, so that the liquefied nitrogen injected from the injection pipe 2 is injected. Stabilizes the flow rate.

  Next, a method of adjusting the injection state of liquefied nitrogen when the object to be cooled is cooled using the liquefied nitrogen injection device 1 having the above-described configuration will be described. This adjustment method is performed by repeating the following “continuous injection” and “replacement of the injection pipe unit 8”. It is assumed that a large number of replacement injection pipe units 8 having different lengths of the injection pipe 2 are prepared in advance. If the length of the injection pipe 2 attached to the liquefied nitrogen injection device 1 from the beginning is, for example, 200 mm, as the replacement injection pipe unit 8, the length of the injection pipe 2 is longer than 200 mm (for example, 250 mm, (300 mm, 350 mm) and those having a length of the injection pipe 2 shorter than 200 mm (for example, 150 mm, 100 mm, 50 mm) are prepared.

  First, as shown in FIG. 3A, the injection pipe 2 is arranged toward the object 29 (or the position where the object 29 is to be arranged), and liquefied nitrogen is continuously added for a predetermined time or more. To spray. At this stage, the object to be cooled may not be actually arranged. Here, the predetermined time is a time (for example, about 20 minutes) necessary for stabilizing the temperature of the injection pipe unit 8 and the like and also stabilizing the state of the liquefied nitrogen to be injected. Whether or not the temperature of the injection pipe unit 8 or the like is stable can be determined by monitoring the temperature obtained from the temperature detectors T1 and T2. For example, when the change in temperature detected by the temperature detector T1 falls within a predetermined range per minute (for example, within 0.5 ° C., within 0.1 ° C., etc.), it can be determined that the temperature is stable.

  Next, continuous injection of liquefied nitrogen from the injection pipe 2 (2A) is started, and after the predetermined time has elapsed and the state of liquefied nitrogen to be injected is stabilized, the liquefied nitrogen injected from the injection pipe 2 is cooled. When the object 29 is in a liquid state (a state in which liquefied nitrogen is linearly connected from the tip of the injection pipe 2 to the position of the object 29 to be cooled), the connection 4 is disconnected and the injection pipe unit 8 (8A) is replaced with another injection pipe unit 8 (8B) having a longer injection pipe 2 (2B) (see FIG. 3B). By increasing the length of the injection pipe 2, the amount of heat input to the injection pipe 2 is increased, the temperature of liquefied nitrogen passing through the inside of the injection pipe 2 becomes relatively high (easily vaporized), and the injected liquefied nitrogen is Then, the liquid state changes from the liquid state to the mist state at a position closer to the injection pipe 2, or changes to the mist state as soon as it comes out of the injection pipe 2.

  On the other hand, after the predetermined time has elapsed after the continuous injection of liquefied nitrogen from the injection pipe 2 is started and the state of the liquefied nitrogen to be injected is stabilized, the liquefied nitrogen injected from the injection pipe 2 is vaporized to be cooled. When the position does not reach position 29 (that is, when mist-like liquefied nitrogen does not reach), the connection portion 4 is disconnected and the injection pipe unit 8 (8A) is connected to the injection pipe 2 (2C) shorter than this. It replaces | exchanges for the provided injection pipe unit 8 (8C) (refer FIG.3 (c)). By shortening the injection pipe 2, the amount of heat input to the injection pipe 2 is reduced, the temperature of liquefied nitrogen passing through the injection pipe 2 is relatively low (becomes difficult to vaporize), and the injected liquefied nitrogen is Thus, the liquid state changes to the mist state at a position further away from the injection pipe 2.

  Next, the replaced injection pipe unit 8 continuously injects liquefied nitrogen again for a predetermined time or longer (this predetermined time is shorter than the initial predetermined time because the parts other than the injection pipe unit are already cooled). Let

  Next, after the predetermined time has elapsed after starting the continuous injection of liquefied nitrogen from the injection pipe 2 and the state of the liquefied nitrogen to be injected is stabilized, the liquefied nitrogen injected from the injection pipe 2 becomes the object 29 to be cooled. When the position is exactly in the mist state, the adjustment work is completed.

  On the other hand, after the predetermined time has elapsed since the start of continuous injection of liquefied nitrogen from the injection pipe 2 and the state of the liquefied nitrogen to be injected is stabilized, the liquefied nitrogen injected from the injection pipe 2 is positioned at the position of the object 29 to be cooled. In a liquid state (a state in which liquefied nitrogen is linearly connected from the tip of the injection pipe 2 to the position of the object to be cooled 29), the injection pipe unit 8 is connected to another injection pipe having a longer injection pipe 2. Replace with pipe unit 8. On the contrary, when the liquefied nitrogen injected from the injection pipe 2 is vaporized and does not reach the position of the object to be cooled 29 (that is, when the mist-like liquefied nitrogen does not reach), the injection pipe unit 8 is injected shorter than this. The injection pipe unit 8 provided with the pipe 2 is replaced.

  After that, until the liquefied nitrogen injected from the injection pipe 2 becomes a mist state at the position of the object to be cooled 29 (or until it becomes a state close to the mist state), the operation of continuously injecting liquefied nitrogen from the injection pipe 2 described above; The operation of replacing the injection pipe unit 8 is repeated alternately.

  It has been confirmed by experimentation by the present inventor that the heat input to the injection pipe 2 increases as the injection pipe 2 becomes longer and the heat input to the injection pipe 2 decreases as the injection pipe 2 becomes shorter. It is done. That is, the present inventor has three types of the ejection pipe unit 8 in which the length of the ejection pipe 2 is 100 mm, the length of the ejection pipe 2 is 200 mm, and the length of the ejection pipe 2 is 300 mm (however, Are prepared as a set of eight jet pipes 2 each having an inner diameter of 0.4 mm and an outer diameter of 1.6 mm.) Each of the jetted liquefied nitrogen is at a distance of 20 to 30 cm from the tip of the jet pipe 2. The valve 13 is operated so as to be in a mist state to adjust the ejection amount, and after the ejection state is stabilized, the temperature detected by the temperature detector T1 (TC1) and the temperature detected by the temperature detector T2 ( TC2) was read. Then, when the value (TC) obtained by subtracting the temperature (TC2) detected by the temperature detector T2 from the temperature (TC1) detected by the temperature detector T1 is confirmed, the length of the jet pipe 2 is 100 mm. TC = 20 ° C., TC = 35 ° C. for the jet pipe 2 having a length of 200 mm, and TC = 53 ° C. for the jet pipe 2 having a length of 300 mm. That is, it was confirmed that the heat input amount to the injection pipe 2 increases as the injection pipe 2 becomes longer. This shows that the longer the injection pipe 2 is, the more easily the liquefied nitrogen ejected from the ejection pipe 2 is vaporized.

  As is clear from the above description, according to the low temperature liquefied gas injection device and the method for adjusting the low temperature liquefied gas injection state according to the embodiment of the present invention, the replacement pipe provided with the injection pipes 2 having different lengths. By preparing a large number of injection pipe units 8 and repeating the operation of continuously injecting liquefied nitrogen from the injection pipe 2 and the operation of replacing the injection pipe unit 8, the injection state can be easily optimized. The cooling efficiency of the object to be cooled 29 can be improved.

  Moreover, according to the low temperature liquefied gas injection device and the method for adjusting the low temperature liquefied gas injection state according to the embodiment of the present invention, the above-described good injection state is maintained even during continuous operation for about 20 hours. be able to.

<Other embodiments>
As shown in FIG. 1, the connection positions of the injection pipe 2 with respect to the main pipe 3 are not all the same. As shown in FIG. 4A, the connection positions of the injection pipe 2 with respect to the main pipe 3 are different from the injection pipe 2A. The difference between the injection pipe 2B and the injection pipe 2B is that if the lengths of the injection pipes 2A and 2B are the same, the position of the tip is shifted between the injection pipes 2A and 2B, and the liquefaction is caused to collide with the cooled object 29 Variations in the state of nitrogen occur. In order to prevent such variation, as shown in FIG. 4B and FIG. 4C, a detour such as a wheel 31 is formed in the middle of some of the injection pipes 2A to form all the injection pipes 2A. , 2B may be substantially aligned.

  In the above-described embodiment, there are a plurality (eight) of the injection pipes 2 provided in the injection pipe unit 8, but it is naturally possible to have one injection pipe 2.

1 Liquid nitrogen injection device (low temperature liquefied gas injection device)
2 Injection pipe 3 Core pipe 4 Connection 6 Liquid nitrogen supply pipe (low temperature liquefied gas supply)
8 Injection pipe unit 29 Object to be cooled

Claims (4)

In the low-temperature liquefied gas injection device detachably equipped with an injection pipe for injecting the low-temperature liquefied gas, a method for adjusting the injection state of the low-temperature liquefied gas,
The low temperature liquefied gas injection device continuously injects low temperature liquefied gas from the injection pipe for a predetermined time,
When the low-temperature liquefied gas injected from the injection pipe is in a liquid state at the position of the object to be cooled after the predetermined time has elapsed, replace the injection pipe with a longer one,
When the low-temperature liquefied gas injected from the injection pipe evaporates after the predetermined time elapses and does not reach the position of the object to be cooled, replace the injection pipe with a shorter one.
A method for adjusting the injection state of the low-temperature liquefied gas. In the low-temperature liquefied gas injection device detachably provided with an injection pipe unit including a plurality of injection pipes of the same length for injecting the low-temperature liquefied gas, a method for adjusting the injection state of the low-temperature liquefied gas,
By the low temperature liquefied gas injection device, low temperature liquefied gas is continuously injected for a predetermined time from a plurality of injection pipes,
When the low-temperature liquefied gas injected from the injection pipe is in a liquid state at the position of the object to be cooled after the predetermined time has elapsed, replace the injection pipe unit with one having a longer injection pipe,
When the low-temperature liquefied gas injected from the injection pipe is vaporized and does not reach the position of the object to be cooled after the predetermined time has elapsed, replace the injection pipe unit with one having a shorter injection pipe.
A method for adjusting the injection state of the low-temperature liquefied gas. In the adjustment method of the injection state of the low-temperature liquefied gas according to claim 2,
The injection pipe unit is
A main pipe having a connection portion connected to the low-temperature liquefied gas supply portion at the base end portion;
A plurality of injection pipes of the same length, each having a base end connected to the main pipe;
Including
A method for adjusting the injection state of the low-temperature liquefied gas. A low-temperature liquefied gas injection device detachably equipped with an injection pipe unit including a plurality of injection pipes of the same length for injecting a low-temperature liquefied gas,
The injection pipe unit is
A main pipe having a connection portion connected to a supply portion of the low-temperature liquefied gas at the base end portion;
A plurality of injection pipes of the same length, each having a base end connected to the main pipe;
Including
A low-temperature liquefied gas injection device characterized by that.

Images