Freeze-drying apparatus for serial cold trap having optimal structural ratio

Abstract

The present invention relates to a freeze-drying apparatus for a serial cold trap having an optimal structural ratio and, more specifically, to a freeze-drying apparatus for a serial cold trap having an optimal structural ratio, in which the optimal structural ratio with respect to a diameter (D) and a horizontal cooling length (L) of a cold trap housing is derived, thereby achieving excellent efficiency of steam capture in a drying chamber, simplified manufacturing, and low manufacturing costs. According to an embodiment of the present invention, the freeze-drying apparatus for a serial cold trap having an optimal structural ratio comprises: a drying chamber which dries an object to be dried in the freeze-drying apparatus; a first cold trap which cools the steam in air flowing from the drying chamber; an intermediate pipe to which the air is discharged from the first cold trap; a second cold trap which cools the steam in the air flowing from the intermediate pipe; a vacuum pump which sucks in the air discharged from the second cold trap, so as to maintain a vacuum state in the drying chamber, the first cold trap, the intermediate pipe, and the second cold trap; and a refrigerant supply device which supplies refrigerant to the first cold trap and the second cold trap, wherein structural ratios (L1 / D1, L2 / D2) between diameters (D1, D2) and horizontal cooling lengths (L1, L2) of first and second cylindrical housings of the first and second cold traps respectively satisfy the ranges of 2 ≤L1 / D1≤ 5 and 2 ≤L2 / D2≤ 5, a structural ratio (D1 / D2) between the diameter (D1) of the first housing and the diameter (D2) of the second housing satisfies a range of D1 / D2 ≥ 1.1, and a structural ratio (V1 / V2) between the volume (V1) of the first housing and the volume (V2) of the second housing satisfies a range of V1 / V2 ≥ 1.1.

Description

Freeze drying device with serial cold traps having optimal structural ratio

[0001] The present invention relates to a freeze-drying device of a serial cold trap having an optimal structural ratio, and more specifically, to a freeze-drying device of a serial cold trap having an optimal structural ratio that has excellent water vapor capture efficiency inside a drying chamber, is simple to manufacture, and has low manufacturing cost by deriving an optimal structural ratio with respect to the diameter (D) of the cold trap housing and the horizontal cooling length (L).

[0002] Unless otherwise indicated herein, the materials described in this section are not prior art to the claims of this application, and their inclusion in this section is not intended to be admitted as prior art.

[0003] A freeze dryer (Freeze drying equipment) is a device that freeze-dries a product inside a drying room by sucking in the air inside the drying room, creating a vacuum, and removing moisture from the sucked air using a cold trap. It is mainly used for experimental or industrial purposes in fields such as food processing and pharmaceuticals.

[0004] The inventor of the present invention has proposed a 'vacuum freeze-drying device with multi-series cold traps', patented under patent registration number 10-1767251, based on the research results and know-how accumulated over more than a decade of research and development on freeze-drying devices.

[0005] The vacuum freeze-drying device having a multi-serial cold trap of the above-mentioned prior patent invention comprises: “a drying room for drying a drying object; a first cold trap connected to the drying room so that air discharged from the drying room can be introduced therein, and cooling water vapor in the air introduced from the drying room; a second cold trap connected to the first cold trap so that air discharged from the first cold trap can be introduced therein, and cooling water vapor in the air introduced from the first cold trap; a vacuum pump for maintaining a vacuum state of the drying room, the first cold trap, and the second cold trap by sucking in air discharged from the second cold trap; a refrigerant supply device for supplying refrigerant to the first cold trap and the second cold trap; and a control unit for controlling the vacuum pump and the refrigerant supply device; wherein the first cold trap comprises a first housing having a cylindrical shape; a hollow tube shape formed long in the central portion of the first housing, and configured to supply air from the drying room to the first cold trap. A first air inlet pipe having one end open so that the incoming air passes through the hollow pipe and flows out into the interior of the first housing; a first opening formed at a predetermined position at the other end of the first air inlet pipe through which the air flows in so that the air flowing out into the interior of the first housing flows out to a second cold trap; and a first refrigerant receiving portion formed at a predetermined position on the inner surface of the first housing and having a hollow cylindrical structure formed in contact with the inner surface of the first housing to cool the air inside the first housing; wherein the second cold trap comprises a second housing having a cylindrical shape; a second air inlet pipe having a hollow tube shape formed long in the central portion of the second housing and having one end open so that the air flowing in from the first cold trap passes through the hollow pipe and flows out into the interior of the second housing; a second air inlet pipe formed at a predetermined position at the other end of the second air inlet pipe through which the air flows in so that the air flowing out into the interior of the second housing flows out to a vacuum pump. opening;And a second refrigerant receiving portion formed at a predetermined position on the inner surface of the second housing and formed in contact with the inner surface of the second housing, the second refrigerant receiving portion cooling the air inside the second housing, wherein the first air inlet pipe and the second air inlet pipe each include a sensor capable of measuring the thickness of ice formed on the inner surfaces of the first housing and the second housing, and the refrigerant supply device includes a refrigerant control portion capable of controlling the amount of refrigerant supplied to the first cold trap and the second cold trap, respectively, and the control portion controls the thickness of ice formed on the inner surface of the first housing and the thickness of ice formed on the inner surface of the second housing to be the same.

[0006] The vacuum freeze-drying device according to the applicant's prior patent registration No. 10-1767251 has the advantage of excellent cooling efficiency for the device by controlling the amount of ice generated from multiple cold traps equally, and excellent efficiency by being able to remove ice generated from the cold traps in batches.

[0007] However, there were problems such as the need to install long first and second air inlet pipes inside the cold trap, the uncertainty of the optimal value for the structural ratio of the diameter (D) of the cold trap and the horizontal cooling length (L), the complexity of the device, the ice generated inside the device sometimes blocking the pipe (passage) or failing to form a uniform ice layer, and the inflow of moisture into the vacuum pump, as well as the high manufacturing cost.

[0008] Accordingly, in order to solve the problems of the conventional vacuum freeze-drying apparatus, the inventor of the present invention has derived an optimal structural ratio of the diameter (D) and horizontal cooling length (L) of the cold trap chamber, thereby developing a new freeze-drying apparatus having a serial cold trap that has excellent water vapor capture efficiency inside the drying chamber, is simple to manufacture, and has low manufacturing cost.

[0009] {Prior art literature}

[0010] [Patent Document]

[0011] (Patent Document 1) Patent Registration No. 10-1767251 (Published on August 10, 2017)

[0012] The present invention has been made to improve upon the above-described conventional problems, and the purpose of the present invention is to provide a freeze-drying device of a serial cold trap having an optimal structural ratio that calculates an optimal structural ratio with respect to the diameter (D) of the cold trap housing and the horizontal cooling length (L) and applies it to a first cold trap and a second cold trap, thereby preventing the phenomenon of ice generated inside the cold trap blocking the pipeline, and thus reducing the device failure rate, as well as having excellent water vapor capture efficiency, a simple structure, and low manufacturing cost.

[0013] In addition, it is obvious that the technical tasks are not limited to the technical tasks described above, and that other technical tasks may be derived from the following description.

[0014] A freeze-drying device of a serial cold trap having an optimal structural ratio according to one embodiment of the present invention comprises: a drying room for drying a dried object; a first cold trap for cooling water vapor in air flowing in from the drying room; an intermediate tube through which air is discharged from the first cold trap; a second cold trap for cooling water vapor in air flowing in from the intermediate tube; a vacuum pump for maintaining a vacuum state in the drying room, the first cold trap, the intermediate tube, and the second cold trap by drawing in air discharged from the second cold trap; And a refrigerant supply device for supplying refrigerant to the first cold trap and the second cold trap; wherein the structural ratios (L1 / D1, L2 / D2) of the diameters (D1, D2) and the horizontal cooling lengths (L1, L2) of the cylindrical first and second housings of the first and second cold traps are in the ranges of 2 ≤ L1 / D1 ≤ 5 and 2 ≤ L2 / D2 ≤ 5, respectively, the structural ratio (D1 / D2) of the first housing diameter (D1) and the second housing diameter (D2) is in the range of D1 / D2 ≥ 1.1, and the structural ratio (V1 / V2) of the volume (V1) of the first housing and the volume (V2) of the second housing are in the range of V1 / V2 ≥ 1.1.

[0015] According to a preferred embodiment of the present invention, the intermediate pipe is characterized in that it is located at the rear end of the horizontal cooling length of the first cold trap and the second cold trap.

[0016] According to a preferred embodiment of the present invention, the connecting pipe of the drying room and vacuum pump connected to the first cold trap and the second cold trap and the end of the hollow pipe are characterized in that they are configured so as not to extend into the internal space of the first and second cold traps.

[0017] According to a preferred embodiment of the present invention, the inner surfaces of the first housing and the second housing are characterized by including a first refrigerant receiving portion and a second refrigerant receiving portion formed in contact with a hollow cylindrical structure.

[0018] According to a preferred embodiment of the present invention, the first cold trap and the second cold trap are arranged in series in parallel vertically, and the intermediate pipe is disposed between the first cold trap and the second cold trap and is vertically connected.

[0019] According to a preferred embodiment of the present invention, ice formed inside the first cold trap does not block the inside of the first cold trap or the inlet of the intermediate pipe, and ice is formed inside both the first and second cold traps.

[0020] According to a preferred embodiment of the present invention, ice is generated in both the first and second cold traps, but no ice is generated in the area from the middle point of the second cold trap to the discharge port.

[0021] According to a preferred embodiment of the present invention, it is characterized in that no moisture is introduced into the vacuum pump that sucks in air discharged from the second cold trap.

[0022] According to the present invention, by applying an optimal structural ratio regarding the diameter (D) of the cold trap housing and the horizontal cooling length (L) to the first cold trap and the second cold trap, there is an effect of preventing the phenomenon of ice generated inside the cold trap blocking (blocking) the pipe.

[0023] In addition, according to the present invention, by applying an optimal structural ratio, not only is the failure rate of the freeze-drying device of the serial cold trap reduced, but also the efficiency of capturing water vapor coming out of the drying room is excellent, and the freeze-drying device has a simple structure and low manufacturing cost, thereby achieving an economic effect.

[0024] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the composition of the invention described in the claims.

[0025]

[0026] FIG. 1 is a schematic cross-sectional view of the entire freeze drying apparatus of a serial cold trap having an optimal structural ratio according to one embodiment of the present invention.

[0027] Figure 2 is a schematic diagram illustrating the operation of a freeze drying device of a serial cold trap having an optimal structural ratio according to one embodiment of the present invention.

[0028] FIG. 3 is a schematic diagram showing the cylindrical diameter (D) and horizontal cooling length (L) of the first and second cold traps of a freeze-drying device having an optimal structural ratio of a serial cold trap according to one embodiment of the present invention.

[0029] FIG. 4 is a schematic cross-sectional view of the entire freeze drying apparatus of a serial cold trap having an optimal structural ratio according to one embodiment of the present invention.

[0030] FIG. 5 is a schematic graph drawing of the operation method of a freeze drying device of a serial cold trap having an optimal structural ratio according to one embodiment of the present invention.

[0031] Figure 6 is a flow chart of a method for calculating the optimal structural ratio design of a freeze drying device of a serial cold trap having an optimal structural ratio according to one embodiment of the present invention.

[0032] FIG. 7 is a photograph of an ice layer formed in the first and second cold traps of a freeze-drying device having an optimal structural ratio of a serial cold trap according to one embodiment of the present invention.

[0033] Figure 8 is a photograph of a prototype of a freeze-drying device with a serial cold trap having an optimal structural ratio according to one embodiment of the present invention.

[0034]

[0035] Hereinafter, a freeze drying device of a serial cold trap having an optimal structural ratio according to a preferred embodiment will be specifically described with reference to the attached drawings.

[0036] For reference, in the drawings below, each component is omitted or schematically illustrated for convenience and clarity, and the size of each component does not reflect the actual size. In addition, the same reference numerals refer to the same components throughout the specification, and drawing numbers for the same components are omitted in individual drawings.

[0037] Referring to FIGS. 1 to 4, one embodiment of the present invention will be described. A freeze-drying device (1000) of a serial cold trap having an optimal structural ratio comprises: a drying room (100) for drying a dried object; a first cold trap (200) for cooling water vapor in air flowing in from the drying room (100); an intermediate tube (300) through which air is discharged from the first cold trap (200); a second cold trap (400) for cooling water vapor in air flowing in from the intermediate tube (300); a vacuum pump (500) for maintaining a vacuum state in the drying room (100), the first cold trap (200), the intermediate tube (300), and the second cold trap (400) by drawing in air discharged from the second cold trap (400); And a refrigerant supply device (600) for supplying refrigerant to the first cold trap (200) and the second cold trap (400); wherein the structural ratios (L1 / D1, L2 / D2) of the diameters (D1, D2) and the horizontal cooling lengths (L1, L2) of the cylindrical first and second housings (210, 410) of the first and second cold traps (200, 400) are in the ranges of 2 ≤ L1 / D1 ≤ 5 and 2 ≤ L2 / D2 ≤ 5, respectively, and the structural ratios (D1 / D2) of the diameters (D1) of the first housing (210) and the diameters (D2) of the second housing (410) are in the ranges of D1 / D2 ≥ 1.1, and the volume (V1) of the first housing (210) and the volume (V2) of the second housing (410) The structural ratio (V1 / V2) is characterized by satisfying all the conditions in the range of V1 / V2 ≥ 1.1.

[0038] More specifically, as illustrated in FIG. 1, the main components of a freeze-drying device (1000) of a serial cold trap having an optimal structural ratio according to one embodiment of the present invention include a drying room (100); a first cold trap (200); an intermediate pipe (300); a second cold trap (400); a vacuum pump (500); and a refrigerant supply device (600).

[0039] At this time, the first cold trap (200) includes a first housing (210) that is a cylindrical chamber formed horizontally long as shown in FIGS. 2 and 3, a first inlet (220) formed at one end of the first housing (210) through which air containing water vapor flows in from the drying room (100), a first discharge port (230) formed at the other end of the first housing (210) through which air containing residual water vapor is discharged to the intermediate pipe (300), and a first refrigerant receiving portion (240) formed at a predetermined position on the inner surface of the first housing (210) and formed as a hollow cylindrical structure formed in contact with the inner circumferential surface of the first housing (210), wherein the first refrigerant receiving portion (240) is configured to cool air containing water vapor inside the first housing (210). Here, the air containing the water vapor moves in the direction of the arrow shown in Fig. 2.

[0040] With reference to FIG. 2, a more specific explanation will be given of the case of driving a freeze drying device (1000) of a serial cold trap having the optimal structural ratio, which is one embodiment of the present invention, in relation to the first cold trap (200).

[0041] First, when the vacuum pump (500) in FIG. 2 is operated, in order to dry the drying material (D) in the drying room (100), the air containing moisture inside the drying room (100) is discharged to the first cold trap (200) through the connecting pipe, and the water vapor contained in the air flowing into the first cold trap (200) is radiantly cooled by the refrigerant supplied from the refrigerant supply device (600), and the water vapor is sequentially sublimated and solidified to attach to the inner wall surface of the first cold trap (200) in the form of ice (F1) to form an ice layer.

[0042] Thereafter, the air including water vapor discharged from the first cold trap (200) moves to the intermediate pipe (300) with a reduced diameter (D3) with a significant portion of the moisture removed. At this time, since the refrigerant supply device (600) does not supply refrigerant to the intermediate pipe (300), the air moved to the intermediate pipe (300) goes through a speed increase and temperature increase stage, and ice is not formed inside the intermediate pipe (300). In this way, the air passing through the intermediate pipe (300) is introduced into the second cold trap (400) as illustrated in FIG. 2 in a state including residual water vapor.

[0043] Therefore, in order to reduce the re-condensation and flow rate in the second cold trap (400) after the velocity and temperature of the flowing air increase, the diameter (D2) of the second cold trap (300) is preferably designed to be larger than the diameter (D3) of the middle pipe (300) so as to satisfy D2 / D3 > 2.0. In addition, since the middle pipe (300) experiences frictional force according to the air flow, the total potential energy (potential energy) decreases according to Bernoulli's principle, so there is an effect in which the air in the second cold trap (400) does not have much moisture.

[0044] Looking more specifically at the second cold trap (400) through FIG. 2, it differs from the first cold trap (200) seen above in the structural ratio of its diameter (D) and length (L), but its overall shape is similar.

[0045] That is, the second cold trap (400) also includes a second housing (410) that is formed horizontally and is like a cylindrical chamber, a second inlet (420) formed at one end of the second housing (210) through which air containing water vapor flows in from the intermediate pipe (300), a second outlet (430) formed at the other end of the second housing (210) through which air is discharged to the vacuum pump (500), and a second refrigerant receiving portion (440) that is formed at a predetermined position on the inner surface of the second housing (410) and is formed in contact with the inner circumferential surface of the second housing (410) to cool the air inside the second housing (410). Here, the air inside the second housing (410) moves in the direction of the arrow shown in FIG. 2.

[0046] In this way, the air including residual water vapor introduced into the second cold trap (400) also goes through the same process as the first cold trap (200), but since a significant portion (60 to 90%) of the water vapor included in the air is removed by the first cold trap (200) according to the volume ratio (V1 / V2) and the diameter ratio (D1 / D2), only the remaining residual water vapor is attached to the inner wall of the second cold trap (400) in the form of ice (F2) to form an ice layer.

[0047] As a result, since all of the water vapor contained in the air and coming from the drying room (100) is removed by the first cold trap (200) and the second cold trap (400) to which the optimal structural ratio of the present invention is applied, the drying efficiency is improved, and the problem of moisture flowing into the interior of the vacuum pump (500) from the second cold trap (400) can also be solved.

[0048] In addition, the first cold trap (200) and the second cold trap (400) of the present invention are arranged in a two-layer structure with the upper and lower layers separated and placed side by side, and the intermediate pipe (300) is interposed between the first cold trap (200) and the second cold trap (400) and arranged vertically, so that the entire pipe is connected in the shortest distance in the shape of the letter 'ㄷ', and air including water vapor in the drying room (100) can be discharged at a high speed, so that there is an advantage in that the drying speed of the drying object can be increased more quickly.

[0049] The operation method of the freeze-drying device of the serial cold trap having the above-described optimal structural ratio can generally follow the graph shown in Fig. 5. Here, section A (pre-freezing section) is a section in which the temperature of the shelf of the drying room (100) is lowered to rapidly cool the drying material, section B (vacuum preparation operation section) is a section in which the first and second cold traps (200, 400, also called a water collection device) are cooled to prepare the operation of the vacuum pump (500), section C (low-temperature sublimation drying section) is a section in which the vacuum pump (500) is automatically operated to start drying when the first and second cold traps (200, 400) are sufficiently cooled, and section D (step-by-step heating sublimation drying section) is a section in which the shelf temperature is gradually increased to shorten the drying time.

[0050] According to a preferred embodiment of the present invention, the structural ratios (L1 / D1, L2 / D2) of the diameters (D1, D2) and the horizontal cooling lengths (L1, L2) of the cylindrical first and second housings (210, 410) of the first and second cold traps (200, 400) are in the ranges of 2 ≤ L1 / D1 ≤ 5 and 2 ≤ L2 / D2 ≤ 5, respectively, the structural ratio (D1 / D2) of the diameter (D1) of the first housing (210) and the diameter (D2) of the second housing (410) is in the range of D1 / D2 ≥ 1.1, and the structural ratio (V1 / V2) of the volume (V1) of the first housing (210) and the volume (V2) of the second housing (410) is in the range of V1 / V2 ≥ 1.1. In addition, according to a preferred embodiment of the present invention, the structural ratio of the diameter (D3) of the intermediate pipe (300) and the diameter (D2) of the second cold trap (400) is characterized in that it is in the range of D2 / D3 > 2.0.

[0051] Here, the horizontal cooling length (L1) in the first housing (210) of the first cold trap (200) means the distance from the first inlet (220) through which air including water vapor flows in to the part where the refrigerant is supplied, just before the point where the middle pipe (300) of the first outlet (230) through which air is discharged to the second cold trap (400) is located, as shown in FIGS. 2 and 3.

[0052] In addition, the horizontal cooling length (L2) in the second housing (410) of the second cold trap (400) means the distance from the second inlet (420) through which air containing residual water vapor flows in to the second outlet (430) through which air from which water vapor has been removed is discharged to the vacuum pump (500).

[0053] The reason why the horizontal cooling length (L1) of the first cold trap (200) is set from the first inlet (220) of the first housing (210) to the first outlet (230) as above is because ice is formed only on the inner surface of the above section.

[0054] Specifically, since the ice formed on the inner surface of the first cold trap (200) is cooled by the first refrigerant receiving portion (240) formed in contact with the inner surface of the housing of the first cold trap (200), the conditions of the cylindrical diameter and horizontal cooling length for the housing of the cold trap are mainly related to factors that significantly affect the efficiency and durability of the freeze-drying device in relation to the location of pipe blockage and ice formation.

[0055] Meanwhile, the horizontal cooling length (L1, L2) of the first and second cold traps (200, 400) may be shorter than the total horizontal length of the first and second housings (210, 410).

[0056] The first condition for having the optimal structural ratio of the present invention is that the structural ratios (L1 / D1, L2 / D2) of the diameters (D1, D2) and horizontal cooling lengths (L1, L2) of the cylindrical first and second housings (210, 410) of the first and second cold traps (200, 400) are in the ranges of 2 ≤ L1 / D1 ≤ 5 and 2 ≤ L2 / D2 ≤ 5, respectively.

[0057] The driving conditions and test examples for the test to derive the above first condition are as follows.

[0058] First, the test run of the present invention follows the test environment and operating method of the freeze-drying device developed by the inventor, as shown in Table 1 and Figure 5 below. Furthermore, the test examples below are results obtained under identical test conditions as described above.

[0059] [Test environment of freeze-drying device]

[0060]

[0061] [Test Example 1] to [Test Example 3] are intended to derive the optimal structural ratio (L / D) of the diameter (D) and horizontal cooling length (L) of the first and second cold traps (200, 400). At this time, it is assumed that the volumes of the first and second cold traps in each test example are both the same V1=V2, and the sum of the total volumes of each is also the same V1+V2=.

[0062] [Example 1]

[0063] Test Example 1 is a freeze-drying device having a serial cold trap composed of a drying room (100), a first cold trap (200), an intermediate pipe (300), a second cold trap (400), a vacuum pump (500), and a refrigerant supply device (600) as shown in FIG. 1, and then 80 kg of regular apples containing 83% moisture are placed on a shelf inside the drying room (100) and the freeze-drying device is operated for 48 hours under certain test environmental conditions (e.g., a cold trap minimum temperature of -60°C, a temperature reduction rate from room temperature to -70°C within 30 minutes, a final vacuum of the drying room of 0.03 mmHg, etc., these conditions are test environmental conditions that are applied equally to other tests). At this time, the volumes of the first and second cold traps (200, 400) are made the same, and the diameter (D1, D2) of the cylindrical shape is 430 mm and the horizontal cooling length (L1, L2) is 860 mm.

[0064] <Structural ratio of diameter (D) and horizontal cooling length (L) of Test Example 1>

[0065] First cold trap (200) → L1 / D1 = 2.0, second cold trap (400) → L2 / D2 = 2.0

[0066] As a result of testing the structural ratios of the diameter (D) and horizontal cooling length (L) of the first and second cold traps as L1:D1 = 2:1 and L2:D2 = 2:1 as described above, as shown in Fig. 7, the pipes inside the first cold trap (200) were not blocked by frozen ice, ice was uniformly distributed inside the first and second cold traps, and moisture did not flow into the vacuum pump (500), so the test results of Test Example 1 were analyzed to be good.

[0067] [Example 2]

[0068] In Test Example 2, the volume of the first and second cold traps (200) was the same as in Test Example 1, but the diameters (D1, D2) and horizontal cooling lengths (L1, L2) were set to 390 mm and 1050 mm, and the structural ratio was set to 1:2.69, and the remaining conditions were the same as in Test Example 1.

[0069] As a result of the test of the above Test Example 2, as in Test Example 1, the pipe inside the first cold trap (200) was not blocked by frozen ice, ice was uniformly distributed inside the first and second cold traps, and moisture did not flow into the vacuum pump (500), so the test result of Test Example 2 was also analyzed to be good.

[0070] [Example 3]

[0071] In Test Example 3, the volume of the first and second cold traps (200) was the same as in Test Examples 1 and 2, but the diameters (D1, D2) and horizontal cooling lengths (L1, L2) were set to 330 mm and 1470 mm, and the structural ratio was set to 1:4.45, and the remaining conditions were the same as in Test Examples 1 and 2.

[0072] The test results of the above test example 3 were also analyzed as good results, such as no ice blockage in the pipe, uniform distribution, and no moisture inflow into the vacuum pump, similar to test examples 1 and 2.

[0073] Next, [Comparative Example 1] to [Comparative Example 3] are for comparing and analyzing the test results with the above [Test Example 1] to [Test Example 3]. At this time, as in Test Examples 1 to 3, it is assumed that the volume of the first and second cold traps in each comparative example is the same as in Test Examples 1 to 3, with V1=V2 and V1+V2=the same value.

[0074] [Comparative Example 1]

[0075] Comparative Example 1 is tested under the same test environment conditions as Test Examples 1 to 3. However, the difference from Test Examples 1 to 3 is that the cylindrical diameters (D1, D2) of the first and second cold traps (200) are 480 mm and the horizontal cooling lengths (L1, L2) are 690 mm.

[0076] That is, the structural ratio of the diameter (D) and the horizontal cooling length (L) is set to the first cold trap (200) → L1: D1 = 1.4: 1.0, and the second cold trap (400) → L2: D2 = 1.4: 1.0.

[0077] As a result of testing the structural ratio of the diameter (D) and horizontal cooling length (L) of the first and second cold traps as L1:D1 = 1.4:1 and L2:D2 = 1.4:1 as described above, the frozen ice was frozen thickly to the end of the housing of the second cold trap (400), resulting in poor results in which moisture flowed into the vacuum pump (500).

[0078] [Comparative Example 2] and [Comparative Example 3]

[0079] In Comparative Example 2, the cylindrical diameters (D1, D2) of the first and second cold traps (200, 400) were 450 mm and the horizontal cooling lengths (L1, L2) were 790 mm. That is, L1 / D1 = L2 / D2 = 1.76.

[0080] In addition, in Comparative Example 3, the cylindrical diameter (D1, D2) of the first and second cold traps (200, 400) was 310 mm and the horizontal cooling length (L1, L2) was 1660 mm. That is, L1 / D1 = L2 / D2 = 5.35.

[0081] As a result of testing the structural ratio of the diameter (D) and the horizontal cooling length (L) as in Comparative Example 2, the frozen ice was thickly frozen to the end of the housing of the second cold trap (400), resulting in moisture flowing into the vacuum pump (500). In the test result of Comparative Example 3, although the pipe was not blocked by ice, ice was not formed inside the second cold trap (400), resulting in a decrease in water collection efficiency, and in particular, it was confirmed that the space efficiency was poor as the horizontal cooling length (L1, L2) became relatively long in relation to the installation of the device.

[0082] As a result of comparing and analyzing test examples 1 to 3 and comparative examples 1 to 3 as above, the results in Table 2 below were derived, and it was analyzed that the preferable structural ratios of the diameters (D1, D2) and horizontal cooling lengths (L1, L2) of the first and second cold traps are in the ranges of 2 ≤ L1 / D1 ≤ 5 and 2 ≤ L2 / D2 ≤ 5, respectively.

[0083] Table 2

[0084]

[0085] Here, good means that the ice shape is crystalline and the entire ice layer is flat and uniform, and bad means that the ice shape is amorphous and the entire ice layer is slanted and uneven.

[0086] Next, [Test Example 4] to [Test Example 6] below are intended to derive the optimal volume structure ratio (V1 / V2) and optimal diameter structure ratio (D1 / D2) of the first and second cold traps (200, 400).

[0087] That is, as a method for deriving the optimal volume structure ratio (V1 / V2) of the first cold trap (200) and the second cold trap (400), tests are conducted by dividing into cases of V1 > V2, V1 = V2, and V1 < V2.

[0088] [Example 4]

[0089] Test Example 4 is performed according to the same test environment and operating method as Test Examples 1 to 3, as shown in Table 1 and Fig. 5, but the test is performed for the condition of V1 > V2. That is, the diameter (D1) of the first cold trap (200) is set to 430 mm, the diameter (D2) of the second cold trap is set to 390 mm (D1 / D2 = 1.1), and the horizontal cooling lengths of the first and second cold traps are set to 860 mm and 780 mm (L1 / L2 = 1.1), respectively, for the test.

[0090] Results of [Example 4]

[0091] As a result of testing in the case where the structural ratio of the volume (V) is V1 > V2 as described above, the pipe inside the first cold trap (200) was not blocked by frozen ice, ice was uniformly distributed inside the first and second cold traps (200, 400), and moisture did not flow into the vacuum pump (500), so the test result of Test Example 4 was analyzed to be good.

[0092] [Example 5]

[0093] Test Example 5 is performed in the same test environment as Test Examples 1 to 3, but the test is performed for the case where V1 = V2 (D1 / D2 = 1.0, L1 / L2 = 1.0). That is, the diameters (D1, D2) of the first and second cold traps (200, 400) are both set to 430 mm, and the horizontal cooling lengths (L1, L2) of the first and second cold traps are also set to 860 mm each.

[0094] Results of [Example 5]

[0095] As a result of testing in the case where the structural ratio of the volume (V) is V1 = V2 as described above, it was analyzed that, as in the above test example 4, the pipe inside the first cold trap (200) was not blocked by frozen ice and ice was uniformly distributed inside the first and second cold traps (200, 400), but a situation occurred in which a small amount of moisture was introduced into the vacuum pump (500).

[0096] [Example 6]

[0097] Test Example 6 is performed in the same test environment as Test Examples 1 to 3, but the test is performed for the case where V1 < V2 (D1 / D2 = 0.9, L1 / L2 = 0.9). That is, the diameter (D1) of the first cold trap (200) is set to 430 mm, the diameter (D2) of the second cold trap is set to 475 mm, and the horizontal cooling lengths (L1, L2) of the first and second cold traps are set to 860 mm and 945 mm, respectively.

[0098] Results of [Example 6]

[0099] As a result of testing in the case where the structural ratio of the volume (V) is V1 < V2 as described above, the inside of the first cold trap (200) was partially blocked by frozen ice, the ice was not uniform inside the first and second cold traps (200, 400), and a lot of moisture flowed into the vacuum pump (500), so the test result of Test Example 6 was analyzed to be poor.

[0100] The above test results can be analyzed and summarized as shown in Table 3.

[0101] Table 3

[0102]

[0103] As shown in Table 3, according to the results of Test Example 4, the desirable optimal volume structure ratio (V1 / V2) of the first and second cold traps (200, 400) is analyzed as V1 / V2 > 1.0.

[0104] However, when the freeze-drying device (1000) is operated by actually operating the vacuum pump (500), the air containing water vapor flowing through the first cold trap (200) to the second cold trap (400) incurs various energy losses, including friction loss in the pipes inside the device, loss at the first and second inlets (220, 420) and the first and second outlets (230, 430), and loss due to change in cross-sectional area immediately after the inlet and outlet.

[0105] The friction and energy loss of the air fluid flow containing water vapor as described above reduce the speed of the working fluid in the second cold trap (400), which becomes a factor in increasing the load on the vacuum pump (500). In order to structurally compensate for this speed reduction, the size of the second cold trap (400) is designed to be smaller to generate a venturi effect, thereby preventing the speed reduction due to friction and energy loss in the second cold trap (400). Accordingly, it is preferable to additionally apply a correction value of 10% to the volume structure ratio (V1 / V2) of the first and second cold traps (200, 400) derived from the analysis in Test Example 4, which is V1 / V2 > 1.0. Therefore, the corrected optimal volume structure ratio (V1 / V2) is set to V1 / V2 ≥ 1.1.

[0106] In addition, the diameter structure ratio (D1 / D2) of the first and second cold traps (200, 400) is also linked to the above-mentioned corrected optimal volume structure ratio set to V1 / V2 ≥ 1.1, so it is preferable to set the diameter structure ratio (D1 / D2) of the first and second cold traps (200, 400) to a range of D1 / D2 ≥ 1.1, in which the diameter (D1) of the first cold trap (200) is at least 10% larger than the diameter (D2) of the second cold trap (400), taking into additional consideration the actual design and field manufacturing environment.

[0107] Meanwhile, although the upper limits of the optimal volume structure ratio and diameter structure ratio are not separately specified, considering the operating load of the freeze-drying device of the present invention, it is preferable that the diameter structure ratio D1 / D2 does not exceed 2.0, and it is also preferable that the volume structure ratio V1 / V2, which is proportional to the square of the diameter, does not exceed 4.0 or more considering the operating load. This is because, in the flow of air containing water vapor, if the volume (V2) and diameter (D2) of the second cold trap (400) are relatively significantly reduced compared to the first cold trap (200), a phenomenon such as a sudden, rapid contraction pipe occurs, and at this time, a large pressure loss (pressure energy loss) of the fluid flow occurs, which places a considerable operating load on the vacuum pump (500).

[0108] As D1 / D2 ≥ 1.1 and V1 / V2 ≥ 1.1 are determined as described above, the optimal structural ratio of the desirable horizontal cooling lengths (L1, L2) of the first and second cold traps (200, 400) can be determined theoretically (formally) without the need to conduct a separate test.

[0109] That is, for example, the general formula for volume is V=πD 2 ×L / 4 and V1 / V2 = (D1 2 / D2 2 ) × (L1 / L2), and in this case, when the diameter structure ratio of the first and second cold traps (200, 400) is selected as D1 / D2 = 1.1, the optimal structure ratio of the horizontal cooling length (L1, L2) that satisfies the condition of V1 / V2 ≥ 1.1 can be derived as an optimal numerical range in which at least L1 / L2 ≥ 0.91 must be present.

[0110] By summarizing all the test results above, the optimal structural ratio of the present invention is derived as follows.

[0111] The first condition for having the optimal structural ratio of the present invention is that the structural ratios (L1 / D1, L2 / D2) of the diameters (D1, D2) and horizontal cooling lengths (L1, L2) of the cylindrical first and second housings (210, 410) of the first and second cold traps (200, 400) are in the ranges of 2 ≤ L1 / D1 ≤ 5 and 2 ≤ L2 / D2 ≤ 5, respectively, the second condition is that the structural ratio (D1 / D2) of the diameter (D1) of the first housing (210) and the diameter (D2) of the second housing (410) is in the range of D1 / D2 ≥ 1.1, and the third condition is that the structural ratio (V1 / V2) of the volume (V1) of the first housing (210) and the volume (V2) of the second housing (410) satisfies the range of V1 / V2 ≥ 1.1.

[0112] In addition, through these features, the first cold trap (200) of the present invention can exhibit optimal effects as a freeze-drying device of a serial cold trap, such as the pipes are not blocked by frozen ice, the ice layer is uniformly distributed within the first and second cold traps (200, 400), and moisture does not flow into the vacuum pump (500).

[0113] Next, a calculation method for designing the optimal structural ratios of D1, D2, L1, and L2 based on the optimal structural ratio of the present invention described above will be described.

[0114] As shown in the flow chart of Fig. 6, first, the design worker sets the diameter (D1) of the first cold trap (200) to an arbitrary value considering the overall scale and operating capacity of the freeze-drying device of the serial cold trap. Next, the value of D2 that satisfies the condition of D1 / D2 ≥ 1.1 can be determined. Next, the values ​​of L1 and L2 that satisfy the conditions of 2 ≤ L1 / D1 ≤ 5 and 2 ≤ L2 / D2 ≤ 5 can be determined. In the next step, it is checked whether the L1 and L2 satisfy V1 / V2 ≥ 1.1, and if so, the values ​​(D1, D2, L1, L2) are selected to perform the design work, and if the conditions are not satisfied, the values ​​of L1 and L2 that satisfy the conditions of 2 ≤ L1 / D1 ≤ 5 and 2 ≤ L2 / D2 ≤ 5 and V1 / V2 ≥ 1.1 are determined again, and the above steps are repeated.

[0115] The calculation method for the optimal structural ratio design as above is explained with the following four examples.

[0116] (1) CASE 1: Select an arbitrary value D1 = 430mm → Select D1 / D2 = 1.1 → Determine D2 = 390mm → Select L1 / D1 = 2.0, L2 / D2 = 2.0 from 2 ≤L1 / D1≤ 5 and 2 ≤L2 / D2≤ 5 → Determine L1 = 860mm, L2 = 780mm → Check whether V1 / V2 ≥ 1.1 is satisfied (i.e., L1 / L2 must be > 0.91) → Since the determined value L1 / L2 = 1.1, the condition is satisfied → Perform design according to the determined value above.

[0117] (2) CASE 2: Select an arbitrary value D1 = 500mm → Select D1 / D2 = 1.5 → Determine D2 = 333mm → Select L1 / D1 = 3.0, L2 / D2 = 3.0 from 2 ≤L1 / D1≤ 5 and 2 ≤L2 / D2≤ 5 → Determine L1 = 1500mm, L2 = 1000mm → Check whether V1 / V2 ≥ 1.1 is satisfied (i.e., L1 / L2 must be > 0.49) → Since the determined value L1 / L2 = 1.5, the condition is satisfied → Perform design according to the determined value above.

[0118] (3) CASE 3: Select an arbitrary value D1 = 450mm → Select D1 / D2 = 1.1 → Determine D2 = 410mm → Select L1 / D1 = 2.0, L2 / D2 = 5.0 from 2 ≤L1 / D1≤ 5 and 2 ≤L2 / D2≤ 5 → Determine L1 = 900mm, L2 = 2050mm → Check whether V1 / V2 ≥ 1.1 is satisfied (i.e., L1 / L2 must be > 0.91) → Since the determined value L1 / L2 = 0.44, the condition is not satisfied → Repeat to satisfy the condition.

[0119] (4) CASE 4: Select an arbitrary value D1 = 400mm → Select D1 / D2 = 1.3 → Determine D2 = 310mm → Select L1 / D1 = 2.0, L2 / D2 = 4.5 from 2 ≤L1 / D1≤ 5 and 2 ≤L2 / D2≤ 5 → Determine L1 = 800mm, L2 = 1400mm → Check whether V1 / V2 ≥ 1.1 is satisfied (i.e., L1 / L2 must be > 0.65) → Since the determined value L1 / L2 = 0.57, the condition is not satisfied → Repeat to satisfy the condition.

[0120] The above CASE 1 to CASE 4 are summarized in Table 4 as follows.

[0121] Table 4

[0122]

[0123] As described above, a prototype of the present invention was designed and manufactured as shown in Fig. 8 through a method for calculating the optimal structural ratio design. The upper and lower circular portions visible on the front in the photograph of Fig. 8 are in accordance with the design conditions of the optimal structural ratio of the diameters D1 and D2 of the first and second cold traps (200, 400).

[0124] Although the preferred embodiments of the present invention have been described with reference to the attached drawings, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application. Therefore, the embodiments described above should be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the claims described below rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the present invention.

[0125] [Explanation of symbols]

[0126] 100: drying room, 200: first cold trap, 210: first housing, 220: first inlet, 230: first outlet, 240: first refrigerant receiving portion, 300: intermediate pipe, 400: second cold trap, 410: second housing, 420: second inlet, 430: second outlet, 440: second refrigerant receiving portion, 500: vacuum pump, 600: refrigerant supply device, 1000: freeze drying device of serial cold trap having optimal structure ratio, D1: diameter of first cold trap, D2: diameter of second cold trap, D3: diameter of intermediate pipe, L1: horizontal cooling length of first cold trap, L2: horizontal cooling length of second cold trap, F1, F2: ice state.

Claims

1. In the freeze drying device, A drying room for drying objects; A first cold trap for cooling water vapor in the air flowing in from the drying room; An intermediate pipe through which air is discharged from the first cold trap; A second cold trap for cooling water vapor in the air flowing in from the above intermediate pipe; A vacuum pump for maintaining a vacuum state in the drying room, the first cold trap, the intermediate pipe, and the second cold trap by sucking in air discharged from the second cold trap; and A refrigerant supply device for supplying refrigerant to the first cold trap and the second cold trap; including: The structural ratios (L1 / D1, L2 / D2) of the diameters (D1, D2) and horizontal cooling lengths (L1, L2) of the cylindrical first and second housings of the first and second cold traps are in the ranges of 2 ≤ L1 / D1 ≤ 5 and 2 ≤ L2 / D2 ≤ 5, respectively. The structural ratio (D1 / D2) of the diameter (D1) of the first housing and the diameter (D2) of the second housing is in the range of D1 / D2 ≥ 1.

1. A freeze-drying device of a serial cold trap having an optimal structural ratio, characterized in that the structural ratio (V1 / V2) of the volume (V1) of the first housing and the volume (V2) of the second housing both satisfy the range of V1 / V2 ≥ 1.

1.

2. In paragraph 1, A freeze drying device of a serial cold trap having an optimal structural ratio, characterized in that the above-mentioned intermediate tube is located at the rear end of the horizontal cooling length of the first cold trap and the second cold trap.

3. In paragraph 1, A freeze drying device of a serial cold trap having an optimal structural ratio, characterized in that the connecting pipe of the drying room and the vacuum pump connected to the first and second cold traps and the end of the hollow pipe are configured so as not to extend into the internal space of the first and second cold traps.

4. In paragraph 1, A freeze-drying device having an optimal structural ratio of a serial cold trap, characterized in that the inner surfaces of the first housing and the second housing include a first refrigerant receiving portion and a second refrigerant receiving portion formed by contacting a hollow cylindrical structure.

5. In paragraph 1, The above first cold trap and the second cold trap are arranged in series in a vertical direction, A freeze drying device having a serial cold trap with an optimal structural ratio, characterized in that the intermediate tube is vertically connected and interposed between the first cold trap and the second cold trap.

6. In paragraph 1, The ice formed inside the first cold trap does not block the inside of the first cold trap or the inlet of the intermediate pipe, A freeze-drying device having a serial cold trap having an optimal structural ratio, characterized in that ice is formed inside both the first and second cold traps.

7. In paragraph 1, A freeze-drying device having a serial cold trap having an optimal structural ratio, characterized in that ice is generated in both the first and second cold traps, but ice is not generated in the area from the middle point of the second cold trap to the discharge port.

8. In paragraph 1, A freeze-drying device of a serial cold trap having an optimal structural ratio, characterized in that no moisture is introduced into the vacuum pump that sucks in air discharged from the second cold trap.

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