JP7762688B2 - Fiber-containing mixed liquid refinement treatment device - Google Patents

Description

The present invention relates to a micronization treatment device for micronizing a mixed liquid containing fibers.

Fibers have a wide variety of properties depending on the type, and can be broadly divided into natural fibers and synthetic fibers. Natural fibers include those that exist naturally, such as cotton, linen, silk, and wool, as well as pulp obtained from the fibers that make up wood and grass. Synthetic fibers are fibers that have been artificially and chemically created by humans, and can be divided into recycled fibers, semi-synthetic fibers, synthetic fibers, and inorganic fibers depending on the raw materials used.

In recent years, there has been a growing demand for natural fibers that address environmental issues such as global warming, and attention is being paid to those with a low environmental impact. For example, there are fibers derived from polysaccharides, in which glucose units are linked in a linear chain via β1-4 bonds, which are found most abundantly on Earth as components of the cell walls of woody plants such as broad-leaved and coniferous trees, and herbaceous plants such as bamboo, reeds, and sorghum. Pulp, which is mass-produced at pulp and paper mills using raw materials such as wood derived from coniferous and broad-leaved trees and bamboo, is a well-known example of this polysaccharide-derived fiber, and its primary component is cellulose. Cellulose is also known as a component of some animals, such as sea squirts, and as a component of nata de coco, which is produced by certain fungi, such as acetic acid bacteria.

Meanwhile, it is known that by reducing the fiber width, fibers can be made into materials with excellent properties such as high strength, high elasticity, and low thermal expansion. To enhance these characteristics, processes such as fibrillation, which raises the fiber surface and increases entanglement, are being used to refine fibers. Here, fibrillation is understood to mean the fuzzing and skewing that occurs when fibers are rubbed, and occurs when the small fibers that make up the fibers, known as fibrils, become fuzzed due to friction. In the textile industry, this phenomenon, known as whitening due to fibrillation—in which the light reflection changes and the fiber appears whitish—is considered to be a defect in the product's appearance. However, as the use of fibers expands across various industries, fibrillation is being used as a method to maximize the functionality of fibers. Fibrillation is expected to provide functions such as reinforcement through fiber entanglement, adsorption of various components by increasing the specific surface area, transparency due to reduced diffuse reflection of light, surface smoothing, and improved feel.

Various fiber refining methods and refining processing devices are being considered, including the manufacturing method described in Patent Document 1.

Patent Document 1 discloses an apparatus for micronizing a mixture of materials containing fibers, which includes at least one discharge section equipped with a discharge port for a flow path of the fiber mixture, at least one supply device for supplying the fiber mixture to the discharge section at a predetermined processing pressure, at least one positioning device for positioning the discharge section, and a movable processing member disposed opposite the discharge section for decomposing the fiber mixture, with a slit-shaped processing area formed between the discharge section and the surface of the movable processing member with which the fiber mixture collides on the flow path of the fiber mixture that has passed through the discharge section.

Special table 2021-517212 publication

Fibers have properties such as their own specific gravity and insolubility in liquid. Due to these properties, fibers in a fiber-containing mixture separate and settle due to differences in specific gravity, but the time it takes for this separation and settling to occur varies depending on the raw material from which the fibers are derived or the fiber width and length of the fibers. Furthermore, because fibers do not completely dissolve in liquid, the fibers in a fiber-containing mixture remain dispersed in the liquid.
Therefore, during the fiber refining process, sedimentation can be prevented in areas where the fiber-containing mixed liquid can be kept in a fluidized state. On the other hand, in areas where it is difficult to keep the fiber-containing mixed liquid in a fluidized state, such as the end of a pipe, the fibers may settle and form a thick agglomerated layer, making it difficult to perform a stable fiber refining process. This is thought to be particularly common with fibers with a large aspect ratio that tend to become entangled with each other and form a cocoon-like shape. The aspect ratio is the value obtained by dividing the fiber length by the fiber width; if this value is higher than 50, entanglement will be strong, and if it exceeds 100, the entanglement will be significant.

In addition, a pressure intensifier may be used in one step of the fiber-containing mixed liquid micronization process, and in this case, a check valve with an internal spring may be used on either the suction side or the discharge side or both of the sides of the pressure intensifier to control the flow direction of the fiber-containing mixed liquid.
When this type of check valve is used, fibers tend to become tangled in the spring. Furthermore, if fibers become tangled in the spring, the check valve will not function properly, and the tangled fibers may accumulate and block the flow path, narrow the flow path, or even completely close the flow path. Furthermore, fibers tangled in the spring may become shives, which may break away from the spring and flow to subsequent processes, clogging the pathways in those processes and preventing stable fiber refining.

Furthermore, one step in the fiber-containing mixed liquid refining process may involve the use of a pressure intensifier and a high-pressure spray nozzle. The pressure intensifier alternately draws in and discharges the fiber-containing mixed liquid at regular intervals, pressurizing and compressing it before sending it to the next process. As a result, there are times when the fiber-containing mixed liquid stagnates near the suction side of the pressure intensifier. Even if this lasts only a few seconds, when refining a mixed liquid containing fibers with relatively wide fiber widths, the fibers may settle and form large, fluffy, or cocoon-like clumps. These clumps then twist as they are sucked into the pressure intensifier, pass through a very narrow high-pressure path, and are sent to an even finer-diameter high-pressure spray nozzle. The pressurized and compressed cocoon-like clumps become very hard during this process, which can cause blockages at the inlet or inside of the high-pressure spray nozzle, preventing stable fiber refining.

The manufacturing apparatus described in Patent Document 1 can improve the quality and homogeneity of the processed fiber mixture by feeding at least a portion, or even the entire amount, of the processed fiber mixture back into the apparatus and repeatedly processing the fiber mixture. It also describes that a circulation system between the collection tank and the supply unit can be very easily used to achieve a predetermined fiber diameter and/or fiber length distribution. It also describes that clogging can be minimized by tilting or bending the movable processing member.
However, as mentioned above, the properties of the fibers in the fiber mixture, such as separation and settling time, vary depending on the raw material from which the fibers are derived, and furthermore, adjusting the gap using a movable processing member to prevent clogging can lead to a deterioration in quality. Therefore, there is room for further improvement in order to perform stable fiber micro-finishing processing.

The present invention aims to provide a micronization processing device that can fluidize a mixed liquid containing fibers of various origins within the micronization processing device, thereby ensuring consistent quality through stable micronization processing.

As a result of extensive research into achieving the above objective, the inventors discovered that the above problem could be solved by using steel spheres with a high specific gravity and by utilizing the pressure of the liquid itself, which has been pressurized by a pressure intensifier, to control the flow direction of the liquid, and by installing a path to prevent the separation and sedimentation of fibers in the raw material.

In other words, the present invention is an apparatus for micronizing a mixed liquid containing fibers, comprising at least a raw material tank, a raw material circulation path including a raw material tank, a raw material circulation pump, a pressure booster, a raw material supply pipe, a feed-side check valve, and a raw material return pipe; a chamber supply high-pressure pipe and a chamber supply high-pressure path including a high-pressure check valve; and a chamber equipped with a micronization means, wherein the raw material return pipe is for returning the raw material to the raw material tank.

The present invention provides a micronization processing device that can maintain a fluid state within the micronization processing device, even when using a mixed liquid containing fibers of various origins, and ensures stable quality through stable micronization processing.

FIG. 1 is a conceptual diagram of an apparatus for treating a fiber-containing mixed liquid according to the present invention. FIG. 2 is a conceptual diagram of a pressure intensifier used in the fiber-containing mixed liquid pulverization treatment device according to the present invention. FIG. 3 is a basic conceptual diagram of a liquid supply side check valve, a high pressure side check valve, and a pressure booster supply pipe used in the fiber-containing mixed liquid micronization treatment device according to the present invention. FIG. 4 is a diagram showing the state of each check valve when the fiber-containing mixed liquid refinement treatment device according to the present invention is stopped (a), when the pressure intensifier 6 is sucking in the raw material (b), and when the pressure intensifier 6 is discharging the raw material (c). FIG. 5 shows electron microscope photographs of ground cotton and cotton after the micronization treatment. FIG. 6 is a conceptual diagram of a conventional microfabrication processing apparatus. FIG. 7 is a graph showing the change in sedimentation height test results over time.

The apparatus for refining a fiber-containing mixed solution according to the present invention will be described below.
However, the following embodiments are provided to aid in understanding the invention and are not intended to limit the invention.

(Definition of terms)
In this specification, the term "raw material" refers to a mixture containing fibers used as a raw material for fiber refining.
The term "micronization treatment" in this specification refers to the application of some physical treatment to a raw material that has been brought to a high pressure state using a pressure intensifier.
In this specification, the term "processing liquid" refers to the liquid obtained after the raw material has been subjected to a micronization process.

As shown in Figure 1, the fiber-containing mixed liquid micronization treatment device 1 of this embodiment is mainly composed of a raw material tank 2 for storing the raw material, a raw material circulation pump 3, a raw material circulation path 4, a chamber supply high-pressure path 5, multiple pressure intensifiers 6, and a chamber 8.

Raw materials are supplied to and stored in the raw material tank 2. The raw material tank may be equipped with a variety of known stirring devices (not shown) to stir the raw materials. The suction port of the raw material circulation pump 3 is connected to the raw material tank 2 via the raw material withdrawal pipe 9.

Raw materials include, for example, cellulose fibers derived from polysaccharides contained in natural plants such as wood fiber, bamboo fiber, sugarcane fiber, seed hair fiber, and leaf fiber; pellicle, a gel-like substance made of 100% cellulose derived from bacterial cellulose (polysaccharide) produced by microorganisms such as acetic acid bacteria; chemical pulp, mechanical pulp, and waste paper made from woody plants such as broad-leaved trees and coniferous trees, and herbaceous plants such as bamboo and reeds; and crop residues derived from plant leaves, flowers, stems, roots, and husks, such as bagasse, rice straw, used tea leaves, and fruit juice residue.

Furthermore, raw materials such as pulp that have been chemically modified as a pretreatment for the micronization process described below can also be used as raw materials in this embodiment. Examples include hydrolysis of polysaccharides with an acid, hydrolysis of polysaccharides with an enzyme, swelling of polysaccharides with an alkali, oxidation of polysaccharides with an oxidizing agent, reduction of polysaccharides with a reducing agent, oxidation with a TEMPO catalyst, phosphate esterification, carbamate conversion, cationization, etc.

The raw material circulation pump 3 is preferably a pump that can transport the fiber-containing mixed liquid without trapping the fibers, and that can transport the liquid even when the viscosity increases, and is preferably a positive displacement metering pump. Among positive displacement metering pumps, foreign matter such as contaminant powder can clog the spray nozzle, so a non-contact pump is preferred to prevent this, and a bead pump, tube pump, or twin-screw pump is particularly preferred.

The raw material circulation path 4 includes a raw material supply pipe 10, a feed-side check valve 11 (described later), and a raw material return pipe 12. The raw material supply pipe 10 connects the raw material circulation pump 3, each feed-side check valve 11, and the raw material return pipe 12 to supply raw material to the pressure booster 6. The raw material supply pipe 10 is provided with a branch 13a for connection to the feed-side check valve 11. The branch 13a and the feed-side check valve 11 may be connected using a pipe such as a T-pipe integrated with the raw material supply pipe 11, or the branch 13a and the feed-side check valve 11 may be connected using a separate pipe. In this case, it is preferable to shorten the distance from the branch 13a to the feed-side check valve 11. It is also preferable to install the feed-side check valve 11 so that it is approximately perpendicular to the floor surface.
Furthermore, it is preferable to connect the branch point 13a and the feed-side check valve 11 so that the distance between them can be within 3 m, preferably within 1 m, and more preferably within 0.5 m. Furthermore, it is preferable to set the fluid flow rate in the raw material supply pipe 10 of the raw material circulation path 4 to 0.5 m/min or more. Furthermore, it is preferable to position the branch point 13a in the height direction at the lowest point in the flow path from the branch point 13a to the check valve 11. This ensures that the flow in the raw material supply pipe 10 always eliminates accumulation of raw material. Furthermore, it is preferable to position a portion of the flow path height behind the branch point 13a of the raw material supply pipe 10 higher than the height of the check valve 11. An air vent may be provided in this portion. This prevents air from being sucked into the pressure booster when air is entrained in the fiber-containing mixed liquid.

The raw material return pipe 12 is connected to the raw material supply pipe 10 at one end and to the raw material tank 2 at the other end using a pipe fitting or the like (not shown) so that the raw material can be returned. This connection allows a portion of the fiber-containing mixed liquid to be supplied to the pressure booster 6 through the raw material supply pipe 10 while a portion of the fiber-containing mixed liquid is returned to the raw material tank 2 through the raw material return pipe 12, ensuring that the raw material does not stagnate and flows continuously through the raw material circulation path 4. The raw material supply pipe 10 is distinguished from the raw material return pipe 12 by the fact that it is a pipe provided with the branch 13a, while the raw material return pipe 12 is a pipe not provided with the branch 13a. It is of course possible to combine the raw material supply pipe 10 and the raw material return pipe 12 into a single pipe. In this case, for convenience, the portion of the pipe provided with the branch 13a is referred to as the raw material supply pipe 10, and the portion of the pipe not provided with the branch 13a is referred to as the raw material return pipe 12.

An automatic adjustment valve (not shown) may be installed in the flow path of the raw material return pipe 12, and a pressure gauge (not shown) may be installed between the raw material circulation pump 3 and the raw material supply pipe 10. Pressurizing the raw material supply pipe 10 facilitates the feeding of raw material into the intensifier 6 via the feed-side check valve 11, helping to prevent negative pressure in the treatment liquid chamber 22. This prevents negative pressure from creating an explosion due to the diesel effect, which could result in scorching or leaching of the sealing components inside the intensifier. These devices allow the raw material supply pressure to be kept constant, stabilizing the operability of the fiber-containing mixed liquid micronization treatment device of the present invention. Furthermore, monitoring the valve opening and pressure within the raw material circulation path allows for early detection of abnormalities.

The chamber supply high-pressure path 5 includes a chamber supply high-pressure pipe 15 and a high-pressure side check valve 14. The high-pressure side check valve 14 is connected to the chamber supply high-pressure pipe 15, and the chamber supply high-pressure pipe 15 is connected to the chamber 8. The chamber supply high-pressure pipe 15 includes a branch portion 13b for connecting the high-pressure side check valve 14. It is also preferable to install the high-pressure side check valve 14 approximately perpendicular to the floor surface. The chamber supply high-pressure pipe 15 is made of a pressure-resistant material such as stainless steel.

Chamber 8 is equipped with a micronization means for carrying out micronization within the chamber. Examples of the micronization means include physical methods such as shear force or cavitation due to changes in pressure or speed, collision with a hard impact body such as an impact ring, or mutual collision of high-pressure jets.

Hereinafter, a case where the micronization treatment is performed using a high-pressure jet nozzle as the micronization treatment means will be described.
A high-pressure spray nozzle 16 extending from and connected to the chamber supply high-pressure pipe 15 is connected to the chamber 8, and the raw material is subjected to a micronization treatment in the chamber 8. In addition, a treatment liquid return pipe 17 and/or a treatment liquid recovery pipe 18 can be connected to the chamber 8 depending on the number of times the micronization treatment is performed.
The processing liquid return pipe 17 is for returning (transporting) the liquid after the raw material has been processed one or more times by the high-pressure spray nozzle 16 in the chamber 8 to the raw material tank 2. Therefore, if the micronization process is performed only once, the processing liquid return pipe 17 does not need to be connected.
On the other hand, the treated liquid recovery pipe 18 is for sending the liquid after the raw material has been treated once or more times by the high-pressure spray nozzle 16 in the chamber 8 to the product tank 19.
In addition, a heat exchanger (not shown) for cooling the processing liquid may be connected to the processing liquid return pipe 17 and the processing liquid recovery pipe 18, so that the processing liquid can be cooled when being sent to the raw material tank 2 and/or when being sent to the product tank 19.

The raw material, which has been pressurized by the pressure intensifier 6, is sent to the high-pressure spray nozzle 16 from the chamber supply high-pressure pipe 15. The sent raw material is sprayed from the high-pressure spray nozzle 16 at a high pressure of 30 to 250 MPa to form a spray stream, and this spray stream is then suddenly and simultaneously reduced in pressure to perform a process of refining the fibers in the raw material. The high-pressure spray nozzle 16 can be a known high-pressure spray nozzle made of ceramics, diamond, sapphire, or the like that is capable of spraying a high-pressure fluid.
Here, the micronization treatment of the raw material may be performed multiple times on the fibers in the raw material. That is, the treatment liquid obtained in the chamber 8 may be sent to the raw material tank 2 using the treatment liquid return pipe 17, and then the micronization treatment may be performed again in the chamber 8. When the micronization treatment is performed multiple times, the treatment liquid is recovered by sending it to the product tank 19 using the treatment liquid recovery pipe 18 as soon as the micronization treatment is completed. The product tank 19 may not be provided, and the raw material tank 2 and the product tank 19 may be shared. Also, the product tank 19 may be used as the raw material tank for the next micronization treatment to perform a second micronization treatment in the series.

Micronization is more likely to proceed if multiple high-pressure spray nozzles are connected to the chamber 8 and the spray flows are collided at a collision angle θ, and when two nozzles are used, the angle θ is preferably 95 to 178°, particularly 100 to 170°. If the angle is less than 95°, for example, if the nozzles are collided at a right angle of 90°, the colliding dispersion is likely to structurally collide directly with the wall of the chamber in some areas, and there are many cases where the degree of polymerization decreases by more than 10% even with a single micronization.
On the other hand, if the angle is greater than 178°, for example, if the collision is 180°, that is, if the collision is performed head-on, the atomization effect will be enhanced, but there is a possibility that the opposing nozzle and surrounding equipment will be damaged. In the case of three nozzles, setting the angle θ to 120° will maximize the collision efficiency while minimizing damage to the nozzle and surrounding equipment.
In addition, a pocket or the like may be provided in the chamber 8 to receive the nozzle jets that are unable to collide with each other in the direction of travel of the nozzle jets and still retain momentum, thereby preventing damage to the equipment.

Furthermore, when the micronization treatment is carried out multiple times, the number of treatments can be arbitrarily adjusted between 1 and 200 times. The properties of the resulting treatment solution become smoother and more uniform with repeated treatments, and the fibers in the solution become thinner and shorter. Therefore, it is possible to repeat the micronization treatment the number of times appropriate for the application.
The pulverization treatment is carried out so that the average particle length of the fibers after pulverization is 1/4 or less, preferably 1/5 to 1/1000, more preferably 1/6 to 1/500, and even more preferably 1/7 to 1/100 of the average particle length of the polysaccharide before pulverization.
Furthermore, a small number of repetitions is preferred to obtain fibers with an average particle length of 100 μm or less, while increasing the number of repetitions to 5 or more is preferred to obtain fibers with an average particle length of 20 μm or less, and at least 10 or more repetitions are preferred to obtain fibers with an average particle length of 10 μm or less.

As shown in Fig. 2, the intensifier 6 has an oil chamber 20 and a treatment liquid chamber 22. The oil chamber 20 has a rod 21b connected to an actuating member 21a. The oil chamber 20 also has a pair of oil inlets and outlets 20a, 20b with the actuating member 21a located in the center. The intensifier 6 also has connection ports 23 for suctioning and discharging raw material, which are connected to the intensifier supply pipe 7.
When oil pressure is applied to the inside of the oil chamber 20 through the oil inlet/outlet 20b and oil is simultaneously discharged from the oil inlet/outlet 20a, the operating member 21a slides (from right to left in the figure), and the raw material is sucked into the treatment liquid chamber 22 through the liquid supply side check valve 11, the booster supply pipe 7, the common pipe 33, and the connection port 23.
On the other hand, when oil pressure is applied to the oil chamber 20 through the oil inlet/outlet 20a and oil is simultaneously discharged from the oil inlet/outlet 20b, the operating member 21a slides (from left to right in the figure), and the raw material in a high-pressure state is discharged from the treatment liquid chamber 22 through the connection port 23, the common pipe 33, the booster supply pipe 7, and the high-pressure side check valve 14.

As a result of the pressure intensifiers 6 operating as described above, the apparatus for micronizing a mixed liquid containing fibers of this embodiment repeatedly sucks and discharges raw material using each pressure intensifier 6, and the raw material is supplied to the chamber 8 in a high-pressure state without interruption and with little pulsation.
In the embodiment described above, the actuating member 21a is driven by hydraulic pressure, but other power sources such as electricity may be used. Furthermore, these may be used in combination. Position control using a servo device can achieve smoother operation.
1 shows a fiber refinement apparatus using three intensifiers, it is also possible to use a single intensifier, or to use four or more intensifiers, each operated with a delay time equal to one cycle per intensifier, thereby more efficiently suppressing pulsation. An odd number is preferable, and three is preferred for the simplest control and cost reduction. It is also possible to use an intensifier with a raw material suction port and raw material discharge port at both ends, with the operating member 21a located in the center.

FIG. 3 shows a basic conceptual diagram of the liquid supply side check valve 11, the high pressure side check valve 14, and the booster supply pipe 7.
The liquid supply side check valve 11 is mainly composed of a ball 25, a housing member 26, a detachable member 24, and a valve seat 34.
The ball 25 is preferably made of a steel ball or the like with a high specific gravity (with a specific gravity in the range of 3 to 9, with 7 to 9 being more preferable), as this will ensure stable operation. Dimension C, which is half the difference between the inner diameter A of the containing member 26 inside the check valve and the outer diameter B of the ball 25, provides the space through which the mixed liquid flows, so the larger dimension C is, the easier the mixed liquid will flow, and the smaller it is, the more difficult it will be to flow. The size of the ball should be selected so that the ratio of dimension C to inner diameter A is 10% to 50%, with 15% to 40% being even better.
The containing member 26 is used to store the detachable member 24 and the ball 25, and the detachable member 24 is used to store the ball 25. The raw material supply pipe 10 and the containing member 26 are connected using a connecting member 27. Here, the connecting member 27 has a function of connecting them, as well as a function as a valve seat for the ball 25.
The detachable member 24 is provided with a liquid passage hole for passing the raw material. This improves the durability of the liquid supply side check valve 11 itself. The size and shape of the liquid passage hole are not particularly limited, but it is preferable to make the liquid passage hole larger to ensure smooth liquid passage and prevent entanglement of fibers. The inside of the detachable member 24 may also be provided with a mechanism such as a groove for guiding the ball 25 when passing the raw material. This allows the ball 25 to operate stably and smoothly without loosening.
The housing member 26 and the connecting member 27 are made of a metal, such as stainless steel, that can withstand pressure to ultra-high pressure. Since the detachable member 24 receives substantially the same pressure from both the outside and the inside, even in a high-pressure environment, it is not subjected to tension, twisting, bending, distortion, etc., and is therefore able to maintain the movement of the ball. Furthermore, any material or thickness is acceptable as long as it can withstand compressive force, and plastic is not limited to metal; plastic can also be used.
The valve seat 34 is used as an auxiliary element to reliably press the ball 25 against the connecting member 27, which functions as a valve seat, to seal the raw material (see FIG. 4( c)). The valve seat 34 is an elastic element with a central fluid passage hole. If sealing were to be achieved by linear contact pressure along the circumference of the ball 25 and connecting member 27 without using the valve seat 34, the sealing performance would be significantly reduced if damage such as scratches were generated at the linear contact point or if foreign matter were to be introduced. Furthermore, the valve seat 34 may not quickly settle into the sealing position. The valve seat 34 is preferably made of an elastic material, preferably a resin, and more preferably one with excellent impact resistance. The use of the valve seat 34 stabilizes operation, improves the volumetric efficiency of the mixed liquid transfer, increases the throughput per stroke, and improves production efficiency.

The high-pressure side check valve 14 is mainly composed of a ball 29, a housing member 30, and a valve seat 35.
The ball 29 may be a steel ball or the like having a heavy specific gravity, similar to the ball 25 .
The containing member 30 is used to contain the ball 29. The chamber supply high-pressure pipe 15 and the containing member 30 are connected using a connecting member 31. Although not shown, the containing member 30 and the connecting member 31 are provided with a liquid passage hole through which the raw material flows when in the state shown in FIG. 4( c ), which will be described later. The size, shape, etc. of the liquid passage hole are not particularly limited. Furthermore, the inside of the containing member 30 may be provided with a groove or the like for guiding the ball 29 when the raw material is passed through. This prevents the ball 29 from becoming loose. Furthermore, although not shown, a member based on the same technical concept as the detachable member 24 may be provided. The containing member 30 and the connecting member 31 are formed of a metal, such as stainless steel, that is resistant to pressure to ultra-high pressure.
Like valve seat 34, valve seat 35 is used auxiliary to reliably press ball 29 against connecting member 28 to seal in the raw material (see FIG. 4(b)). Its structure and material are the same as those of valve seat 34. Note that connecting member 28 also functions as a valve seat for ball 29, similar to connecting member 27.

The booster supply pipe 7 is connected to the high-pressure side check valve 14 using a connecting member 28, to the liquid feed side check valve 11 using a connecting member 32, and to the booster 6 using a branch pipe 33. In this case, the shape of the booster supply pipe 7 itself is not particularly limited, but it is preferable that the connecting member 28 has a shape that corresponds to the installation of the liquid feed side check valve 11 and the high-pressure side check valve 14 so that they are approximately perpendicular to the floor surface.
In another embodiment, as long as it is possible to connect the components so as to allow the raw material to pass through and to enable stable production of the fiber refinement device, other methods or means may be used for connection, such as forming the components other than the detachable member 24, the balls 25, 29, and the valve seats 34, 35 into an integrated structure by machining. In this case, openings are provided that allow the liquid to pass through when the balls 25, 29 are located above and away from the connecting members 27, 28. Furthermore, the upper portions of the connecting members 27, 28 are provided with valve seats 34, 35 to ensure sealing when the balls are located below.

4A shows a state in which the fiber refinement device is stopped, (b) a state in which the intensifier 6 is sucking in the raw material, and (c) a state in which the intensifier 6 is discharging the raw material. The solid arrows in the figure indicate the flow of the raw material. The dashed arrows in the figure indicate that the raw material does not flow in the direction of the arrow.
State (a) shows that both ball 25 and ball 29 are at the bottom.
In addition, in state (b), a downward force of (1) + (2) + (3) is applied to ball 29 due to (1) the pressure toward ball 25 caused by the high-pressure raw material in the chamber supply high-pressure pipe, (2) the suction force of pressure intensifier 6, and (3) its own weight.
On the other hand, an upward force of (1) + (2) - (3) is applied to the ball 25 due to (1) the suction force of the pressure intensifier 6, (2) the discharge pressure of the raw material circulating pump 3, and (3) its own weight.

In state (c), the ball 29 is subjected to (1) an upward force due to the pressurization of the pressure intensifier 6, (2) a downward force due to the internal pressure of the chamber supply high-pressure pipe, and (3) an upward force of (1)-(2)-(3) due to its own weight.
On the other hand, a downward force of (1) - (2) + (3) is applied to the ball 25 due to (1) the downward pressure force from the pressure intensifier 6, (2) the upward force from the discharge pressure of the pump 3, and (3) its own downward weight.

As described above, by using steel balls with a heavy specific gravity for balls 25 and 29 and by installing feed side check valve 11 and high pressure side check valve 14 approximately perpendicular to the floor surface, balls 25 and 29 are installed so that they can move approximately perpendicular to the floor surface, and each ball can fall under its own weight, making it possible to pass the raw material in only one direction.
Furthermore, the liquid supply side check valve and high pressure side check valve of the present invention are advantageous in that they contribute to stable fiber refinement processing by preventing fibers in the dispersion from becoming entangled in the spiral iron wire of a spring, which has occurred in check valves that use elastic bodies such as springs in the past, and also in that they prevent the outflow of shives into the high-pressure spray nozzle, thereby eliminating clogging.
Therefore, the liquid supply side check valve and high pressure side check valve according to the present invention can also be called a check valve that does not use a spring, a check valve that does not use a ball-retaining elastic body, or a valve that utilizes gravity and changes in flow pressure.

The fiber refinement device according to the present invention having the above-mentioned configuration has the following advantages: As a specific example, a case where pulp is used as the raw material will be described below.
By circulating the pulp mixture liquid between the raw material tank 2 and the raw material circulation path 4, the pulp can be made to flow in the raw material circulation path. By making it in this state, it is possible to prevent the pulp mixture liquid from stagnating and settling in the path, which would cause a partial increase in the pulp concentration, and to eliminate malfunctions at the beginning of production and during production.

In addition, when the treatment liquid discharged from chamber 8 is returned to raw material tank 2 and multiple refining processes are performed, the mixed liquid can be returned to raw material tank 2. Therefore, even if the viscosity gradually increases as the pulp is refined during the pulp refining process, by circulating the raw material at a constant flow rate above a certain level, the thixotropy of the raw material itself will allow the liquid to be maintained in a fluid state with low viscosity, making it possible to carry out the fiber refining process stably.

The present invention will be explained below based on examples, but the present invention is not limited to these examples.

(Fiber length measurement)
Using a fiber length measuring device (FS5 manufactured by Valmet), the fiber lengths of hardwood pulp, softwood pulp, bamboo pulp, and ground cotton were measured in accordance with JIS P 8226-2:2011. Note that fibers with longer fiber lengths and larger aspect ratios tend to become entangled more easily with the spring inside the check valve. The measurement results are shown in Table 1.

(Settling height test)
The concentrations of hardwood pulp, softwood pulp, bamboo pulp, ground cotton, and chitin powder were adjusted to 1 wt%, and a pulp settling height test was conducted using a 50 ml centrifuge tube. The ratio of the settling height Hx at the time of measurement to the liquid surface height _H0 of the mixed liquid containing fiber at the start of each test after 0 to 15 minutes (Hx/ _H0 x 100) is shown.
Here, this settling height test is for evaluating the state inside the pipes of the micronization treatment device when the raw material is stagnated inside the pipes.
The larger the initial rate of change, the more quickly the fiber separates from the water and settles. The smaller the value after 24 hours, the smaller the volume occupied by the water-retaining fibers and the more likely they are to form a tight fiber bundle. The larger the value after 24 hours, the more likely the fibers are to spread out in a network-like manner in water and become entangled in the spring.
The measurement results are shown in Table 2, and a graph showing the time course is shown in FIG.
Cotton and chitin are considered to be raw materials that tend to settle in the pipes because they drain quickly in the initial stage (after 1 minute).
Furthermore, coniferous trees and bamboo have a high chance of settling to a high depth after 24 hours, and are therefore considered to be materials that are likely to become tangled in the spring and cause problems.
On the other hand, based on the difference in settling height after 15 minutes and after 24 hours (88.5 - 74.0 = 14.5%), it can be said that hardwood pulp has the property of settling slowly and gently, and is therefore considered to be a raw material with a high possibility of being able to undergo stable defibration processing.

(Freeness measurement)
In accordance with JIS P 8121-2:2012, aqueous mixtures of hardwood pulp, softwood pulp, bamboo pulp, and ground cotton fibers and chitin powder were prepared and subjected to freeness measurements. Freeness measurements were performed to evaluate the ease of drainage when shear was applied. The higher the freeness measurement value, the faster the drainage, and it is believed that fibers that instantly lost water would clog the piping. The measurement results are shown in Table 3. Ground cotton is a fiber with a drying history, and its high freeness value and poor affinity with water likely cause rapid drainage, making stable processing difficult using conventional equipment without a circulation system. On the other hand, chitin powder has a lower freeness and is more compatible with water than hardwood pulp and other fibers.

Example 1
Using the fiber-containing mixed solution refining treatment apparatus of the present invention shown in Figure 1, refining treatment using softwood pulp with a solids concentration of 1% as the raw material was carried out four times at a pressure of 200 MPa and a high-pressure spray nozzle with an inner diameter of 0.5 mm. Here, a repetition is referred to as a pass, and four repetitions are referred to as 4 passes. After each refining treatment, a portion of the treatment solution was sampled and diluted with pure water to a solids concentration of 0.1%, and the transmittance at 800 nm was measured. The measurement results are shown in Table 4.

Example 2
The pulp was refined in the same manner as in Example 1, except that bamboo pulp with a solid concentration of 1% was used as the raw material. The measurement results are shown in Table 4.

Example 3
The pulverization treatment was carried out in the same manner as in Example 1, except that ground cotton with a solid concentration of 1% was used as the raw material. The measurement results are shown in Table 4. Electron microscope photographs of the ground cotton and after 4 passes are shown in Figure 5.

Example 4
The pulverization treatment was carried out in the same manner as in Example 1, except that chitin powder with a solid concentration of 1% was used as the raw material, and it was confirmed that the pulverization treatment could be carried out without any problems.

Table 4 shows that for all raw materials, the transmittance decreased as the number of passes increased, indicating that fibers refined by high-pressure treatment were present in the supernatant and that this increased as the number of passes increased. Figure 5 also shows that cotton was refined to a fiber width of 25 nm or less, with some fibers being refined to a fiber width of 15 nm or less.

(Comparative Example 1)
A conventional refining treatment apparatus 36 shown in FIG. 6 was used, which had spring-loaded check valves 39 on both the suction and discharge sides of the booster and no path for circulating the raw material, and softwood pulp with a solid concentration of 1% was used as the raw material for refining treatment.

(Comparative Example 2)
The pulverization treatment was carried out in the same manner as in Comparative Example 1, except that ground cotton with a solid concentration of 1% was used as the raw material.

(result)
In Comparative Example 1, the micronization device stopped during the first treatment shortly after it started, and when the piping was removed and the inside was inspected, fibers were found to be tangled around the spring. It was not possible to perform the second micronization treatment. In Comparative Example 2, the treatment liquid stopped being discharged immediately after it started. When the piping was removed and the inside was inspected, fibers were found to be tangled around the spring, and the surrounding piping was also filled with fibers, causing the piping to be clogged with cotton. It was not possible to perform the micronization treatment continuously.

1... fiber-containing mixed liquid micronization device, 2... raw material tank, 3... raw material circulation pump, 4... raw material circulation path, 5... chamber supply high-pressure path, 6... pressure booster, 7... pressure booster supply piping, 8... chamber, 9... raw material withdrawal piping, 10... raw material supply piping, 11... liquid supply side check valve, 12... raw material return piping, 13a, 13b... branching section, 14... high-pressure side check valve, 15... chamber supply high-pressure piping, 16... high-pressure spray nozzle, 17... treatment liquid return piping, 18... treatment liquid recovery piping, 19... product tank, 20... oil chamber 20a, 20b... oil inlet/outlet, 21a... operating member, 21b... rod, 22... treatment liquid chamber, 23... connection port, 24... detachable member, 25... ball, 26... accommodation member, 27... connection member, 28... connection member, 29... ball, 30... accommodation member, 31... connection member, 32... connection member, 33... branch pipe, 34... low-pressure side valve seat, 35... high-pressure side valve seat, 36... conventional micronization treatment device, 37... pressure booster, 38... micronization treatment means, 39... check valve using spring, 40... heat exchanger, 41... raw material tank

Claims (5)

At least a raw material tank, a raw material circulation pump,
A booster and
a raw material circulation path including a raw material supply pipe, a liquid supply side check valve, and a raw material return pipe;
a chamber supply high-pressure path including a chamber supply high-pressure pipe and a high-pressure side check valve;
A fiber-containing mixed solution pulverization treatment apparatus comprising: a chamber equipped with a pulverization treatment means;
The liquid supply side check valve and the high pressure side check valve are configured to use hard balls and do not use springs,
the raw material tank and the raw material circulation path are connected via a raw material circulation pump,
the raw material circulation path and the chamber supply high pressure path are connected via the pressure booster;
the chamber supply high pressure path is connected to the chamber,
The raw material return pipe is for returning the raw material to the raw material tank. The liquid supply side check valve is installed so as to be approximately perpendicular to the floor surface.
A device for treating a mixed solution containing the fibers according to claim 1 to refine the fibers. The liquid supply side check valve has a removable member for accommodating the hard ball therein .
A device for treating a mixed solution containing the fibers according to claim 1 to refine the fibers. The detachable member is provided with a liquid passage hole for passing the raw material.
A device for treating a mixed solution containing the fibers according to claim 3 to make them finer. The specific gravity of the steel ball used in the liquid supply side check valve is 3 to 9.
A method for treating a mixed solution containing the fibers according to any one of claims 1 to 4.