JP2016217650A - Deaeration system and refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deaeration system capable of performing deaeration by feeding liquid to a hollow fiber membrane module while keeping a state in which gas is sucked from the hollow fiber membrane module by one unit of pump.SOLUTION: This invention relates to a deaeration system comprising a liquid tank 3, a hollow fiber membrane module 5 for deaeration, a liquid supply line constituted by a plurality of pipings 21, 23 so as to supply water from the liquid tank 3 to the hollow fiber membrane module 5 for deaeration, a displacement pump 7, a decompression container 9, a first deaeration line 29, and a second deaeration line 31. One state in which gas is sucked from the decompression container 9 under operation of the displacement pump 7 to cause an inside part of the decompression pump 9 to show negative pressure and the other state in which liquid flows from the liquid tank 3 to the hollow fiber membrane module 5 for deaeration under operation of the displacement pump 7 are changed over and gas flows from the hollow fiber membrane module 5 for deaeration to the decompression container 9 even in any state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a deaeration system and a refrigerator.

2. Description of the Related Art Conventionally, home refrigerators are provided with an ice making device that stores water in an ice tray to make ice. For example, when water is put in a liquid tank installed in a refrigerator compartment, the water in the liquid tank is automatically sent to an ice making device by a liquid feed pump to make ice, and the ice made is removed from the ice tray. Are stored.
In many cases, ice made in a refrigerator for home use becomes opaque because air dissolved in water is trapped as bubbles during ice making.
Therefore, various studies have been conducted to obtain transparent ice.
For example, in Patent Document 1, a microwave heating unit that includes a cooling unit that cools an object to be frozen, a freezing chamber that houses the object to be frozen, and a microwave generation unit that absorbs microwaves and generates heat in the freezing chamber. There has been proposed a refrigeration apparatus provided with an ice tray provided with a body and irradiating the ice tray with the microwave generated by the microwave generating means.
However, in this case, there is a problem that the apparatus becomes large.

  On the other hand, as a liquid degassing method, a method using a hollow fiber membrane module is known. In this method, for example, the outside of the hollow fiber membrane is decompressed, and the liquid is circulated through the hollow portion of the hollow fiber membrane. Then, the gas in the liquid flowing through the hollow portion permeates the hollow fiber membrane and the liquid is deaerated. Or the hollow part of a hollow fiber membrane is pressure-reduced and a liquid is distribute | circulated outside the hollow fiber membrane. Then, the gas in the liquid that flows outside the hollow fiber membrane permeates the hollow fiber membrane and the liquid is deaerated. In these methods, a vacuum pump for sucking gas from the hollow fiber membrane module and reducing the pressure, and a liquid feed pump for circulating liquid through the hollow fiber membrane module are generally used (for example, patents). Reference 2).

JP 2012-149810 A JP-A-6-55162

As a result of various studies, the present inventors have arranged a degassing hollow fiber membrane module and a vacuum pump in the refrigerator to degas water from the liquid tank, and ice making this is a highly transparent ice. It was found that it is effective in obtaining. Since only a hollow fiber membrane module and a vacuum pump need be arranged between the liquid tank and the ice making device, the device configuration is also simple.
However, disposing the hollow fiber membrane module and the vacuum pump in the refrigerator is not preferable because a lot of electric power and space are required.

The present invention provides a degassing system capable of supplying a liquid to the hollow fiber membrane module and degassing it while maintaining a state where gas is sucked from the hollow fiber membrane module with a single pump. The purpose is to do.
The present invention is capable of supplying a liquid to the hollow fiber membrane module and degassing it with a single pump while maintaining a state where gas is sucked from the hollow fiber membrane module. Another object of the present invention is to provide a refrigerator capable of generating the above.

The present invention has the following aspects.
[1] A liquid tank, a degassing hollow fiber membrane module,
A liquid supply line for supplying liquid from the liquid tank to the degassing hollow fiber membrane module;
A positive displacement pump provided in the middle of the liquid supply line;
A decompression vessel connected to the exhaust port of the degassing hollow fiber membrane module;
A first deaeration line branched from the liquid supply line upstream of the positive displacement pump and connected to the decompression vessel;
A second deaeration line branched from the liquid supply line downstream of the positive displacement pump;
With
The positive displacement pump is selectively connected to a first degassing line of the liquid tank and the first degassing line, and a second degassing of the degassing hollow fiber membrane module and the second degassing line. A gas line is selectively connected to the gas line, gas is sucked from the decompression container by the operation of the positive displacement pump, and the inside of the decompression container is set to a negative pressure;
The positive displacement pump is selectively connected to a liquid tank of the liquid tank and the first degassing line, and a degassing hollow fiber membrane of the degassing hollow fiber membrane module and the second degassing line Selectively connected to the module, and the state where the liquid is supplied from the liquid tank to the hollow fiber membrane module for deaeration by the operation of the positive displacement pump is switched,
In any of the state in which the inside of the decompression vessel is set to a negative pressure and the state in which liquid flows into the deaeration hollow fiber membrane module, the gas flows from the deaeration hollow fiber membrane module into the decompression vessel. Deaeration system characterized by becoming.
[2] The deaeration system according to [1] and an ice making device are provided,
The ice making device is connected to the degassing hollow fiber membrane module of the degassing system and supplied to the degassing hollow fiber membrane module in a state where liquid is supplied to the degassing hollow fiber membrane module. The refrigerated liquid is supplied to the ice making device after passing through the degassing hollow fiber membrane module.

In the deaeration system of the present invention, water for ice making is fed to the hollow fiber membrane module while maintaining the state where gas is sucked from the hollow fiber membrane module with one pump. Can be degassed.
In the refrigerator of the present invention, a single pump is used to maintain the state where gas is sucked from the hollow fiber membrane module, while supplying water for ice making to the hollow fiber membrane module and deaeration. Can produce ice with high transparency.

It is a schematic structure figure of deaeration system 100 of a first embodiment of the present invention. It is a schematic block diagram of the deaeration system 200 of 2nd embodiment of this invention. It is a schematic block diagram which shows a part of structure of the refrigerator 300 of 3rd embodiment of this invention.

  Hereinafter, the present invention will be described with reference to the accompanying drawings.

<First embodiment>
FIG. 1 is a schematic configuration diagram of a deaeration system 100 according to a first embodiment of the present invention.
The degassing system 100 includes a liquid tank 3, a degassing hollow fiber membrane module 5, a positive displacement pump 7, a decompression vessel 9, a control device 11, and a plurality of pipes 21 and 23. 3, a liquid supply line for supplying water to the degassing hollow fiber membrane module 5, a first degassing line 29, and a second degassing line 31. The degassing hollow fiber membrane module 5 is connected to a pipe 25 for taking out the liquid that has passed through the degassing hollow fiber membrane module 5.

The positive displacement pump 7 is provided in the middle of the liquid supply line. Specifically, the liquid tank 3 and the positive displacement pump 7 are connected by a pipe 21, and the positive displacement pump 7 and the degassing hollow fiber membrane module 5 are connected by a pipe 23.
The first deaeration line 29 branches from the pipe 21 that is a liquid supply line on the upstream side of the positive displacement pump 7 and is connected to the decompression vessel 9.
The second deaeration line 31 branches from a pipe 23 that is a liquid supply line on the downstream side of the positive displacement pump 7. The downstream end of the second deaeration line 31 is open to the atmosphere.
Valves 41, 43, 45, and 47 are provided on the pipe 21, the pipe 23, the first deaeration line 29, and the second deaeration line 31, respectively.

The control device 11 is electrically connected to the valves 41, 43, 45, 47 and the positive displacement pump 7. The control device 11 can switch between the following two states (1A) and (1B).
(1A) A state in which the valves 41 and 43 are closed, the valves 45 and 47 are opened, and the operation of the positive displacement pump 7 causes the gas to be sucked from the decompression vessel 9 and the inside of the decompression vessel 9 to be negative pressure.
(1B) A state in which the valves 41 and 43 are open, the valves 45 and 47 are closed, and the liquid is supplied from the liquid tank 3 to the degassing hollow fiber membrane module 5 by the operation of the positive displacement pump 7.
In the present invention, an inexpensive check valve can be used as the valve.

In the state (1A), the positive displacement pump 7 is selectively connected to the first degassing line 29 among the liquid tank 3 and the first degassing line 29, and the degassing hollow fiber membrane module 5 and the second degassing line 29 are connected. The degassing line 31 is selectively connected to the second degassing line 31. As a result, the gas in the decompression vessel 9 is sucked and discharged through the first deaeration line 29, the pipe 21, the pipe 23 and the second deaeration line 31.
In the state (1B), the positive displacement pump 7 is selectively connected to the liquid tank 3 among the liquid tank 3 and the first degassing line 29, and the degassing hollow fiber membrane module 5 and the second degassing line are connected. 31 is selectively connected to the degassing hollow fiber membrane module 5. Thereby, the liquid in the liquid tank 3 is supplied to the degassing hollow fiber membrane module 5 through the pipes 21 and 23.

(Hollow fiber membrane module for deaeration)
The degassing hollow fiber membrane module 5 is an internal perfusion type hollow fiber membrane module that flows a liquid to be degassed inside the hollow fiber membrane (hollow part) and decompresses the outside of the hollow fiber membrane. Specifically, a plurality of hollow fiber membranes (not shown) and a module case 51 for housing the plurality of hollow fiber membranes are provided, and each of the plurality of hollow fiber membranes is opened in the module case 51 with both ends opened. An inlet 51a for introducing a liquid to be degassed (liquid from the liquid tank 3) into each hollow portion of the plurality of hollow fiber membranes is formed at one end of the module case 51, At the other end of the module case 51, an outlet 51b through which the liquid that passed through the hollow portions of the plurality of hollow fiber membranes flows out is formed, and one exhaust port 51c is formed at the side of the module case 51. Is.
The decompression vessel 9 is connected to the exhaust port 51c through the pipe 27.
Pipes 23 and 25 of the liquid supply line are connected to the inflow port 51a and the outflow port 51b, respectively.

Since the hollow fiber membrane provided in the degassing hollow fiber membrane module 5 is for deaeration, it has gas permeability that allows gas to pass between the hollow portion and the outside of the hollow fiber membrane.
The inner diameter of the hollow fiber membrane is preferably 200 μm or more, and more preferably 220 μm or more. The inner diameter of the hollow fiber membrane is preferably 300 μm or less. When the inner diameter of the hollow fiber membrane is equal to or more than the above lower limit value, the pressure loss during liquid passage can be reduced. Further, even if vibration of the hollow fiber membrane occurs during deaeration, the hollow fiber membrane is not easily damaged. On the other hand, when the inner diameter of the hollow fiber membrane is not more than the above upper limit value, a sufficient number of hollow fiber membranes can be accommodated in the module case 51, and good deaeration performance can be maintained.

  The thickness of the hollow fiber membrane is preferably 30 to 70 μm, more preferably 40 to 65 μm. When the film thickness is not less than the lower limit of the above range, the durability when the outside (outer peripheral part) of the hollow fiber membrane in the module case 51 is repeatedly reduced in pressure is excellent. When the film thickness is not more than the upper limit of the above range, the deaeration performance can be maintained satisfactorily.

The film thickness of the hollow fiber membrane is calculated by the following formula (1) from the difference between the inner diameter and the outer diameter of the hollow fiber membrane.
Film thickness of hollow fiber membrane = (outer diameter of hollow fiber membrane−inner diameter of hollow fiber membrane) / 2 (1)
The inner diameter and outer diameter of the hollow fiber membrane are measured as follows.
First, several hollow fiber membranes are bundled, and the entire outside thereof is covered with polyurethane resin, and the hollow portion of each hollow fiber membrane is filled with polyurethane resin and cured. Next, the cured bundle is sliced along the radial direction of the hollow fiber membrane so that the length in the longitudinal direction is about 0.5 mm, and a flaky sample having a thickness of about 0.5 mm is obtained. Next, an optical image of the cross section of the sample is projected onto a screen at a magnification of, for example, 100 using a projector. In the projected image, the outer diameter and inner diameter of each hollow fiber membrane are measured. The operation of cutting out and measuring the sample in this manner is repeated three times, and the average value of all three values is taken as the outer diameter and inner diameter of the hollow fiber membrane.

The hollow fiber membrane is a composite membrane having a gas-permeable homogeneous layer and a porous support layer that protects the homogeneous layer, in that it is excellent in strength and can be degassed efficiently. preferable. For example, dissolved gas can be effectively removed while suppressing liquid leakage.
The specific layer structure of the composite membrane is preferably a two-layer structure in which a porous support layer is provided inside or outside the homogeneous layer, or a three-layer structure in which a porous support layer is provided inside and outside the homogeneous layer. A three-layer structure is more preferable in terms of strength and deaeration performance.

As the gas permeability of the homogeneous layer, it is preferable that the nitrogen gas permeability coefficient is 0.5 barr or more and the oxygen gas permeability coefficient is 1.5 barr or more.
The material of the homogeneous layer is silicon rubber resin such as polydimethylsiloxane, copolymer of silicon and polycarbonate; copolymer of ethylene and α-olefin, poly-4-methylpentene-1, low density polyethylene, high density Polyethylene, linear low density polyethylene, linear ultra low density polyethylene, polypropylene, ionomer resin, ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid copolymer, ethylene / methyl (meth) acrylate Polyolefins such as polymers and modified polyolefins (for example, reaction products of olefin homopolymers or copolymers with unsaturated carboxylic acids such as maleic acid and fumaric acid, acid anhydrides, esters or metal salts). Resin; Fluorine-containing resin such as polyvinylidene fluoride and polytetrafluoroethylene; Polyphenylene oxide; cellulosic resins such as cellulose poly-4-vinyl pyridine; polyurethane resin; and the like. These resins may be used alone or in a blend of two or more. Also, copolymers of these resins can be used.

Among these, as the material for the homogeneous layer, a polyurethane resin or a polyolefin resin is preferable. These are preferably used depending on the application. For example, when the liquid to be deaerated is water-based, it is preferable to use polyurethane-based resin, and when it is solvent-based, polyolefin-based resin is preferably used.
The density of the polyolefin resin is preferably 0.850 to 0.910 g / cm ³ . A homogeneous layer formed of a polyolefin resin having a density within the above range has excellent degassing performance and a practically suitable melting point or softening point even when a liquid to be treated is passed at a high flow rate. The polyolefin resin having a density in the above range has a melting point (Tm) measured by a differential scanning calorimeter (DSC) of about 40 to 100 ° C. The density is measured based on JIS K 7112 (same definition as ASTM D1505).
The polyurethane resin is preferably a segmented polyurethane resin. If it is a segmented polyurethane resin, stable gas permeability can be obtained after shaping into a hollow fiber membrane.

The polyolefin resin forming the homogeneous layer is preferably an ethylene / α-olefin copolymer having a molecular weight distribution of 4.0 or less, obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms.
Examples of the α-olefin having 3 to 20 carbon atoms include propylene (3 carbon atoms), isobutylene (4 carbon atoms), 1-butene (4 carbon atoms), 1-pentene (5 carbon atoms), 1-hexene (carbon number). 6), 4-methyl-1-pentene (carbon number 6), 1-octene (carbon number 8). The α-olefin having 3 to 20 carbon atoms is preferably an α-olefin having 4 to 20 carbon atoms, more preferably an α-olefin having 6 to 8 carbon atoms, and particularly preferably 1-hexene or 1-octene. A C3-C20 alpha olefin may be used individually by 1 type, or may use 2 or more types together.

As described above, the molecular weight distribution of the ethylene / α-olefin copolymer is preferably 4.0 or less, more preferably 3.5 or less, and particularly preferably 3.0 or less. The ethylene / α-olefin copolymer having a small molecular weight distribution can be obtained by a method of copolymerizing using a metallocene catalyst. For example, it can be obtained by a copolymerization method using a constrained geometric catalyst which is a kind of so-called metallocene catalyst developed by Dow Chemical Company.
The molecular weight distribution is the ratio (Mw / Mn) between the mass average molecular weight (Mw) and the number average molecular weight (Mn). The mass average molecular weight (Mw) and the number average molecular weight (Mn) are determined by gel permeation chromatography (GPC) using polystyrene as a standard sample.

  An ethylene / α-olefin copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms is obtained by copolymerizing an α-olefin having 3 to 20 carbon atoms using 10 mol% or more of all monomers. What copolymerized using 20-40 mol% is more preferable.

The melt flow rate (MFR) of the polyolefin resin forming the homogeneous layer is preferably from 0.1 to 5 g / 10 min, and more preferably from 0.3 to 2 g / 10 min at 190 ° C. When the MFR is not less than the lower limit of the above range, the homogenous layer has excellent moldability. When the MFR is not more than the upper limit of the above range, the polyolefin resin is prevented from flowing out to the porous support layer during the production of the hollow fiber membrane, and therefore, the thickness is uniform and excellent deaeration A homogeneous layer having performance can be formed.
The MFR is a value measured at a test temperature of 190 ° C. and a test load of 2.16 kgf (21.18 N) according to ASTM D1238 E condition.

  Examples of commercially available ethylene / α-olefin copolymers suitable for forming a homogeneous layer include “AFFINITY (registered trademark)” manufactured by Dow Chemical Co., Ltd., wherein the α-olefin has 8 carbon atoms, α- Examples include “Evolue (registered trademark)” manufactured by Prime Polymer Co., Ltd., whose olefin has 6 carbon atoms.

  The polyolefin resin forming the homogeneous layer may contain additives such as antioxidants, ultraviolet absorbers, lubricants, antiblocking agents, colorants, flame retardants, etc., as necessary, in addition to the resin. It may be added as long as the object of the present invention is not impaired.

  Examples of the material for the porous support layer include silicon rubber-based resins such as polydimethylsiloxane, a copolymer of silicon and polycarbonate; polyolefins such as poly-4-methylpentene-1, poly-3-methylbutene-1, low-density polyethylene, and polypropylene. Fluorine-containing resins such as polyvinylidene fluoride and polytetrafluoroethylene; Cellulosic resins such as ethyl cellulose; Polyphenylene oxide; Poly-4-vinylpyridine; Urethane resins; Polystyrene; Polyetheretherketone; . These resins may be used alone or in a blend of two or more. Also, copolymers of these resins can be used.

The pore diameter of the porous support layer is preferably in the range of 0.01 to 1 μm. When the pore diameter is not less than the lower limit of the above range, the gas permeability increases and the deaeration performance is excellent. When the pore diameter is less than or equal to the upper limit of the above range, the performance of preventing particles and moisture from entering the pores is excellent.
The porosity of the porous support layer is preferably 30 to 80% by volume. When the porosity is at least the lower limit of the above range, the gas permeability is improved and the deaeration performance is excellent. When the porosity is not more than the upper limit of the above range, the mechanical strength such as pressure resistance of the hollow fiber membrane is improved.

The thicknesses of the homogeneous layer and the porous support layer are preferably determined so that the film thickness is within the above range, and within that range, the thickness of the homogeneous layer is preferably 0.3 to 2 μm. 30-70 micrometers is preferable and, as for the thickness of a porous support layer, 35-65 micrometers is more preferable.
Here, the thickness of the porous support layer refers to the case where the porous support layer is composed of a plurality of layers (for example, a total of two porous support layers, one on each of the inner side and the outer side of the homogeneous layer). In other cases, the total thickness of the plurality of layers. If the thickness of the homogeneous layer and the porous support layer is not less than the lower limit of the above range, the pressure resistance, mechanical strength, etc. of the hollow fiber membrane will be improved. Gas permeability is improved and deaeration performance is excellent. Further, the outer diameter of the hollow fiber membrane does not become too large, and a sufficient number of hollow fiber membranes can be accommodated in the module case 51.

The thicknesses of the homogeneous layer and the porous support layer can be measured from the projected image of the cross section of the flaky sample in the same manner as the method for measuring the inner and outer diameters of the hollow fiber membrane described above, and are obtained as an average value. That is, as described above, a flaky sample having a thickness of about 0.5 mm is obtained, and an optical image of a cross section of the sample is projected onto a screen at a magnification of, for example, 100 using a projector, and the obtained projection is obtained. In the image, the thickness of the homogeneous layer and the porous support layer in each hollow fiber membrane is measured.
The operation of cutting out and measuring the sample in this manner is repeated three times, and the average value of all three values is taken as the thickness of the homogeneous layer and the porous support layer of the hollow fiber membrane.
However, since the thickness of the homogeneous layer is usually much smaller than the thickness of the porous support layer, actual measurement may be difficult. In that case, it is considered that “the thickness of the hollow fiber membrane” calculated by the above formula (1) = “the thickness of the porous support layer”.

  There is no restriction | limiting in particular in the combination of the material of a homogeneous layer and a porous support layer, You may use combining a different kind of resin, or combining the same kind of resin.

A composite hollow fiber membrane having a homogeneous layer and a porous support layer can be produced by a known method having a multilayer composite spinning step and a stretched porous step.
For example, a concentric composite nozzle in which an inner layer nozzle portion, an intermediate layer nozzle portion, and an outer layer nozzle portion are sequentially formed is used, and a molten resin for forming a porous support layer is formed on the outer layer nozzle portion and the inner layer nozzle portion. The molten resin for forming a homogeneous layer is supplied to the intermediate layer nozzle portion. Then, each molten resin is extruded from a concentric composite nozzle and solidified by cooling to obtain unstretched hollow fibers (multilayer composite spinning process). Next, the unstretched hollow fiber is stretched to make the inner layer and the outer layer porous (stretched porous process). Thereby, a hollow fiber membrane having a three-layer structure including a homogeneous layer and a porous support layer that is located inside and outside the homogeneous layer and supports the homogeneous layer is obtained.

  The material of the module case 51 is preferably one having an appropriate mechanical strength. Specific examples include hard polyvinyl chloride resin; polycarbonate; polysulfone resin; polyolefin resin such as polypropylene; acrylic resin; ABS resin; modified polyphenylene oxide.

  Examples of the resin that fixes the hollow fiber membrane in the module case 51 while maintaining its open state include curable liquid resins such as epoxy resins, unsaturated epoxy resins, and polyurethane resins, and resins that melt a polyolefin. Can be mentioned. The resin also acts as a sealing material that hermetically partitions the liquid channel side through which the liquid flows and the gas channel side from which the gas removed from the liquid is exhausted.

(Displacement pump)
The positive displacement pump 7 is a suction pump that sucks gas from the decompression vessel 9 in the state (1A), and sends liquid from the liquid tank 3 to the degassing hollow fiber membrane module 5 in the state (1B). Functions as a feed pump. The positive displacement pump 7 has an advantage that both gas and liquid can be sucked / pumped compared to other pumps.
Examples of the positive displacement pump 7 include a reciprocating pump such as a diaphragm pump, a piston pump, and a plunger pump, and a rotary pump such as a gear pump, a vane pump, and a screw pump, and any of them may be used. Among these, a diaphragm pump is preferable because it is small and can secure a high head.

(Vacuum container)
The decompression vessel 9 is not particularly limited as long as it has a space capable of decompression.
Examples of the material of the decompression container 9 include metals such as stainless steel and resins such as polypropylene and polyethylene.
The internal volume of the decompression vessel 9 is appropriately set according to the amount of liquid to be degassed, and consequently the amount of gas to be degassed.
For example, the amount of liquid (water or the like) supplied to the ice making device of the refrigerator at a time is about 50 to 300 mL. With such an amount, the internal volume of the vacuum container 9 is preferably 100~1000cm ^3, 300~600cm ³ is more preferable. If the internal volume is equal to or more than the lower limit value, the negative pressure in the decompression vessel 9 is sufficiently maintained while the entire amount of the supplied liquid is deaerated. If an internal volume is below the said upper limit, a deaeration system can be compactized.

(Operation of deaeration system)
In the deaeration system 100, first, the control device 11 closes the valves 41 and 43 and opens the valves 45 and 47, and operates the positive displacement pump 7. Thereby, gas is attracted | sucked through the 1st deaeration line 29 and the piping 21 from the pressure reduction container 9, and the inside of the pressure reduction container 9 is made into a negative pressure. The gas sucked from the decompression vessel 9 passes through the first deaeration line 29, the pipe 21, the pipe 23 and the second deaeration line 31 and is discharged from the downstream end of the second deaeration line 31.
When the decompression container 9 becomes negative pressure, gas flows from the degassing hollow fiber membrane module 5 into the decompression container 9 through the pipe 27. Thereby, the pressure outside the hollow fiber membrane in the module case 51 is reduced. The suction of the gas from the decompression container 9 is performed for a preset time so that the interior of the decompression container 9 and the module case 51 are sufficiently decompressed.
Next, the control device 11 switches the valves 41 and 43 to the open state and the valves 45 and 47 to the closed state. Thereby, the liquid in the liquid tank 3 is sent to the degassing hollow fiber membrane module 5 through the pipes 21 and 23 and flows into the degassing hollow fiber membrane module 5 from the inlet 51a. The liquid that has flowed in is introduced into the hollow portion of the hollow fiber membrane from one end of the hollow fiber membrane that is open in the module case 51, and flows through the hollow portion. At this time, since the outside of the hollow fiber membrane in the module case 51 is in a decompressed state, the gas contained in the liquid flowing through the hollow portion of the hollow fiber membrane permeates from the inside to the outside of the hollow fiber membrane. Deaeration is performed to obtain a degassed liquid (a degassed liquid).
The obtained degassed liquid flows out from the outlet 51b of the degassing hollow fiber membrane module 5.
Further, the gas removed from the liquid flows into the decompression vessel 9 from the exhaust port 51c through the pipe 27 because the decompression vessel 9 has a negative pressure. Therefore, the state where the outside of the hollow fiber membrane in the module case 51 is decompressed, that is, the state in which the liquid can be deaerated is maintained. Further, if the decompression container 9 is provided in a sufficiently large size, the decompression container 9 is kept at a negative pressure while the entire amount of the supplied liquid is deaerated even if the degassed gas flows into the decompression container 9. The state of is maintained.

(Function and effect)
In the deaeration system 100 of the present embodiment, as described above, a state where the gas is sucked from the decompression container 9 and the decompression container 9 is brought to a negative pressure, and the liquid is removed from the liquid tank 3. In any of the states supplied to the module 5, gas flows from the degassing hollow fiber membrane module 5 into the decompression vessel 9. Therefore, in a state where the liquid is supplied from the liquid tank 3 to the degassing hollow fiber membrane module 5, the outside of the hollow fiber membrane in the module case 51 is decompressed without suction by the positive displacement pump 7. Is maintained, and the liquid can be degassed.
The decompression container 9 serves as a negative pressure buffer and suppresses an increase in pressure in the module case 51 while the gas is not sucked by the positive displacement pump 7. When there is no decompression container 9 and the first degassing line 29 is directly connected to the exhaust port 51c, degassing is performed immediately after switching, but the pressure in the module case 51 immediately increases after degassing starts. Therefore, it is difficult to sufficiently deaerate the entire amount of the supplied liquid.

Therefore, in the deaeration system 100 of the present embodiment, it is necessary to provide two independent pumps for the suction (decompression) of the gas from the deaeration hollow fiber membrane module 5 and the liquid feeding. No, the liquid can be degassed by sucking gas and feeding liquid with a single pump. Therefore, the deaeration system can be reduced in size compared to the case where two pumps are used.
Moreover, the degassing hollow fiber membrane module 5 is excellent in degassing efficiency. In particular, the internal perfusion type hollow fiber membrane module is more efficient at degassing a small amount of liquid than the external perfusion type hollow fiber membrane module in which the liquid to be deaerated flows outside the hollow fiber membrane. Excellent. Therefore, even when a small amount of liquid is supplied, it can be efficiently degassed and a liquid with a small amount of dissolved gas can be obtained. For example, when the liquid is water, ice with high transparency can be obtained by making the obtained degassed liquid (degassed water).

(Use)
Examples of the use of the deaeration system 100 include household electrical appliances such as a refrigerator and a water server, an ink jet printer, and various analysis devices. Examples of the liquid to be degassed include water, ink, a specimen, and a reagent.
The deaeration system 100 has a limited space where the system can be installed, has a high demand for compactness, and is highly useful in applications where the amount of liquid supplied at one time is small. It is useful for the refrigerator equipped.

<Second embodiment>
FIG. 2 is a schematic configuration diagram of a deaeration system 200 according to the second embodiment of the present invention. In the embodiment described below, the same reference numerals are given to the components corresponding to the previous embodiment, and the detailed description thereof is omitted.
The deaeration system 200 includes a liquid tank 3, a deaeration hollow fiber membrane module 5, a positive displacement pump 7, a decompression vessel 9, a control device 11, and a plurality of pipes 21 and 23. 3, a liquid supply line for supplying water to the degassing hollow fiber membrane module 5, a first degassing line 29, and a second degassing line 31. The degassing hollow fiber membrane module 5 is connected to a pipe 25 for taking out the liquid that has passed through the degassing hollow fiber membrane module 5.

  In the deaeration system 200, the valve 41 in the first embodiment is used as a three-way valve 61, the first deaeration line 29 is connected to the three-way valve 61, and the valve 43 is used as a three-way valve 63 to the three-way valve 63. 31 is the same as the deaeration system 100 except that the control device 13 is provided instead of the control device 11 without connecting the valves 45 and 47.

The three-way valve 61 selectively connects either the liquid tank 3 or the first degassing line 29 to the positive displacement pump 7.
The three-way valve 63 is configured to selectively connect either the degassing hollow fiber membrane module 5 or the second degassing line 31 to the positive displacement pump 7.

The control device 13 is electrically connected to the three-way valves 61 and 63 and the positive displacement pump 7. The control device 13 can switch between the following two states (2A) and (2B).
(2A) The three-way valve 61 selectively connects the first degassing line 29 of the liquid tank 3 and the first degassing line 29 to the positive displacement pump 7, and the three-way valve 63 is a hollow fiber membrane module for degassing 5 and the second degassing line 31 are selectively connected to the positive displacement pump 7, and by the operation of the positive displacement pump 7, gas is sucked from the decompression vessel 9, A state of negative pressure.
(2B) The three-way valve 61 selectively connects the liquid tank 3 of the liquid tank 3 and the first degassing line 29 to the positive displacement pump 7, and the three-way valve 63 includes the degassing hollow fiber membrane module 5 and the first degassing line 29. Of the two degassing lines 31, the degassing hollow fiber membrane module 5 is selectively connected to the positive displacement pump 7, and the operation of the positive displacement pump 7 causes the liquid to flow from the liquid tank 3 to the degassing hollow fiber membrane module 5. Supplied state.

(Operation of deaeration system)
In the deaeration system 200, first, the control device 13 causes the three-way valve 61 to selectively connect the first degassing line 29 to the positive displacement pump 7, and the three-way valve 63 sets the second degassing line 31 to the volume. The positive displacement pump 7 is operated by selectively connecting to the mold pump 7. Thereby, gas is attracted | sucked through the 1st deaeration line 29 and the piping 21 from the pressure reduction container 9, and the inside of the pressure reduction container 9 is made into a negative pressure. The gas sucked from the decompression vessel 9 passes through the first deaeration line 29, the pipe 21, the pipe 23 and the second deaeration line 31 and is discharged from the downstream end of the second deaeration line 31.
When the decompression container 9 becomes negative pressure, gas flows from the degassing hollow fiber membrane module 5 into the decompression container 9 through the pipe 27. Thereby, the pressure outside the hollow fiber membrane in the module case 51 is reduced. The suction of the gas from the decompression container 9 is performed for a preset time so that the interior of the decompression container 9 and the module case 51 are sufficiently decompressed.
Next, the three-way valve 61 selectively connects the liquid tank 3 to the positive displacement pump 7 and the three-way valve 63 selectively connects the degassing hollow fiber membrane module 5 to the positive displacement pump 7 by the control device 13. Switch to connected state. Thereby, the liquid in the liquid tank 3 is sent to the degassing hollow fiber membrane module 5 through the pipes 21 and 23 and flows into the degassing hollow fiber membrane module 5 from the inlet 51a. The liquid that has flowed in is introduced into the hollow portion of the hollow fiber membrane from one end of the hollow fiber membrane that is open in the module case 51, and flows through the hollow portion. At this time, since the outside of the hollow fiber membrane in the module case 51 is in a decompressed state, the gas contained in the liquid flowing through the hollow portion of the hollow fiber membrane permeates from the inside to the outside of the hollow fiber membrane. Deaeration is performed to obtain a degassed liquid (a degassed liquid).
The obtained degassed liquid flows out from the outlet 51b of the degassing hollow fiber membrane module 5.
Further, the gas removed from the liquid flows into the decompression vessel 9 from the exhaust port 51c through the pipe 27 because the decompression vessel 9 has a negative pressure. Therefore, the state where the outside of the hollow fiber membrane in the module case 51 is decompressed, that is, the state in which the liquid can be deaerated is maintained. Further, if the decompression container 9 is provided in a sufficiently large size, the decompression container 9 is kept at a negative pressure while the entire amount of the supplied liquid is deaerated even if the degassed gas flows into the decompression container 9. The state of is maintained.

(Function and effect)
In the deaeration system 200 of the present embodiment, as described above, a state where the gas is sucked from the decompression container 9 and the decompression container 9 is set to a negative pressure and a hollow fiber membrane for degassing the liquid from the liquid tank 3. In any state of flowing into the module 5, gas flows from the degassing hollow fiber membrane module 5 into the decompression vessel 9. Therefore, as in the refrigerator of the first embodiment, in the state where the liquid flows from the liquid tank 3 into the degassing hollow fiber membrane module 5, the hollow in the module case 51 can be obtained without suction by the positive displacement pump 7. The state where the outside of the thread membrane is decompressed is maintained, and the liquid can be deaerated. Therefore, it is not necessary to provide two independent pumps for gas suction and liquid feeding, and the deaeration system can be downsized. In addition, the supplied liquid can be efficiently degassed, and a degassed liquid with less dissolved gas can be obtained.

(Use)
As a use of the deaeration system 200, the thing similar to what was mentioned by 1st embodiment is mentioned.

<Third embodiment>
FIG. 3 is a schematic configuration diagram showing a part of the configuration of the refrigerator 300 according to the third embodiment of the present invention.
The refrigerator 300 of this embodiment includes a deaeration system 100 and an ice making device 110.
The ice making device 110 is connected to the downstream side of the degassing hollow fiber membrane module 5 of the degassing system 100. Specifically, it is connected to the outflow port 51 b of the degassing hollow fiber membrane module 5 through the pipe 25. Thus, in a state where the liquid is supplied to the degassing hollow fiber membrane module 5, the ice supply device 110 is supplied after the liquid supplied to the degassing hollow fiber membrane module 5 passes through the degassing hollow fiber membrane module 5. To be supplied.
As the ice making device 110, a known device can be used and is not particularly limited.

In the refrigerator 300 of the present embodiment, first, the control device 11 of the deaeration system 100 sets the valves 41 and 43 to the closed state and the valves 45 and 47 to the open state, and operates the positive displacement pump 7. Thereby, gas is attracted | sucked through the 1st deaeration line 29 and the piping 21 from the pressure reduction container 9, and the inside of the pressure reduction container 9 is made into a negative pressure. The gas sucked from the decompression vessel 9 passes through the first deaeration line 29, the pipe 21, the pipe 23 and the second deaeration line 31 and is discharged from the downstream end of the second deaeration line 31.
When the decompression container 9 becomes negative pressure, gas flows from the degassing hollow fiber membrane module 5 into the decompression container 9 through the pipe 27. Thereby, the pressure outside the hollow fiber membrane in the module case 51 is reduced. The suction of the gas from the decompression container 9 is performed for a preset time so that the interior of the decompression container 9 and the module case 51 are sufficiently decompressed.
Next, the control device 11 switches the valves 41 and 43 to the open state and the valves 45 and 47 to the closed state. Thereby, the liquid (for example, water) in the liquid tank 3 is sent to the degassing hollow fiber membrane module 5 through the pipes 21 and 23 and flows into the degassing hollow fiber membrane module 5 from the inflow port 51a. The liquid that has flowed in is introduced into the hollow portion of the hollow fiber membrane from one end of the hollow fiber membrane that is open in the module case 51, and flows through the hollow portion. At this time, since the outside of the hollow fiber membrane in the module case 51 is in a decompressed state, the gas contained in the liquid flowing through the hollow portion of the hollow fiber membrane permeates from the inside to the outside of the hollow fiber membrane. Deaeration is performed to obtain a degassed liquid (a degassed liquid).
The obtained degassing liquid flows out from the outlet 51b of the degassing hollow fiber membrane module 5, is supplied to the ice making device 110 through the pipe 25, and is stored in an ice making tray in the ice making device 110 for ice making. . After the ice making, the obtained ice is deiced from, for example, an ice tray and stored in the ice making device 110.
Further, the gas removed from the liquid flows into the decompression vessel 9 from the exhaust port 51c through the pipe 27 because the decompression vessel 9 has a negative pressure. Therefore, the state where the outside of the hollow fiber membrane in the module case 51 is decompressed, that is, the state in which the liquid can be deaerated is maintained. Further, since the amount of liquid supplied to the ice making device 110 of the refrigerator at a time is as small as several hundred mL and the amount of degassed gas is small, the degassed gas flows into the decompression vessel 9. However, while the whole amount of the supplied liquid is deaerated, the decompression container 9 is maintained in a negative pressure state.

(Function and effect)
In the refrigerator 300 of the present embodiment, as described above, two independent pumps are provided for suction (decompression) of gas from the degassing hollow fiber membrane module 5 and liquid feeding, respectively. There is no need, and the liquid can be deaerated by sucking gas and feeding liquid with a single pump. Therefore, the deaeration system can be reduced in size compared to the case where two pumps are used.
Moreover, the degassing hollow fiber membrane module 5 is excellent in degassing efficiency. Therefore, even when a small amount of liquid is supplied, the liquid can be efficiently degassed, and a liquid with a small amount of dissolved gas can be obtained. When this is made with the ice making device 110, ice with high transparency can be obtained.

As mentioned above, although embodiment was shown and the deaeration system and refrigerator of this invention were demonstrated, this invention is not limited to these embodiments. Each configuration in the above embodiment, a combination thereof, and the like are examples, and the addition, omission, replacement, and other modifications of the configuration can be made without departing from the spirit of the present invention.
For example, in the degassing system of the present invention, in the above-described embodiment, an example in which the degassing hollow fiber membrane module 5 has one exhaust port is shown, but the number of exhaust ports may be two or more.

The deaeration system with which the refrigerator of this invention is provided is not limited to the deaeration system 100, For example, the deaeration system 200 may be sufficient.
A water purifier may be provided between the liquid tank 3 and the degassing hollow fiber membrane module 5. When a water purifier is provided on the upstream side of the degassing hollow fiber membrane module 5, minerals, trihalomethane, iron rust and the like contained in the water are removed, so that ice with higher transparency and higher quality can be obtained. .
As a water purifier, a well-known thing can be used and it does not specifically limit. For example, what is provided with a housing and the filter medium accommodated in the housing is mentioned. Examples of the filter medium include a filter such as a hollow fiber membrane, an adsorbent such as activated carbon, an ion exchange resin, and an ion exchange fiber. Any of these filter media may be used alone or in combination of two or more.

DESCRIPTION OF SYMBOLS 3 Liquid tank 5 Degassing hollow fiber membrane module 7 Positive displacement pump 9 Depressurization vessel 11,13 Controller 21,23,25,27 Piping 29 First deaeration line 31 Second deaeration line 41,43,45,47 Valve 51 Module case 51a Inlet 51b Outlet 51c Exhaust 61, 63 Three-way valve 100, 200 Deaeration system 110 Ice making device 300 Refrigerator

Claims (2)

A liquid tank,
A hollow fiber membrane module for deaeration,
A liquid supply line for supplying liquid from the liquid tank to the degassing hollow fiber membrane module;
A positive displacement pump provided in the middle of the liquid supply line;
A decompression vessel connected to the exhaust port of the degassing hollow fiber membrane module;
A first deaeration line branched from the liquid supply line upstream of the positive displacement pump and connected to the decompression vessel;
A second deaeration line branched from the liquid supply line downstream of the positive displacement pump;
With
The positive displacement pump is selectively connected to a first degassing line of the liquid tank and the first degassing line, and a second degassing of the degassing hollow fiber membrane module and the second degassing line. A gas line is selectively connected to the gas line, gas is sucked from the decompression container by the operation of the displacement pump, and the interior of the decompression container is set to a negative pressure, and the displacement pump includes the liquid tank and the first pump. Selectively connected to a liquid tank in one degassing line, and selectively connected to a degassing hollow fiber membrane module in the degassing hollow fiber membrane module and the second degassing line, and the positive displacement pump The state in which the liquid is supplied from the liquid tank to the degassing hollow fiber membrane module by the operation of is switched,
In any of the state in which the inside of the decompression vessel is set to a negative pressure and the state in which liquid flows into the deaeration hollow fiber membrane module, the gas flows from the deaeration hollow fiber membrane module into the decompression vessel. Deaeration system characterized by becoming. A deaeration system according to claim 1 and an ice making device,
The ice making device is connected to the degassing hollow fiber membrane module of the degassing system and supplied to the degassing hollow fiber membrane module in a state where liquid is supplied to the degassing hollow fiber membrane module. The refrigerated liquid is supplied to the ice making device after passing through the degassing hollow fiber membrane module.

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