JP2922802B2 - Filtration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter, and more particularly, to a filter.
The present invention relates to a filtration device for filtering a raw material slurry → cake washing → drying or filtering the raw material slurry to take out solid particles in the raw material slurry in a dry powder state or a wet cake state.

[0002]

2. Description of the Related Art As this type of apparatus, a Nutsche-type filtration and drying apparatus is widely known, which is a single apparatus and a closed system. It can perform many functions such as filtration, washing, and drying, and can safely handle toxic substances, flammable substances, odorous substances, etc., and has the features that its mechanism is relatively simple. Therefore, it is widely used in the fields of food industry, pharmaceutical industry, chemical industry and the like.

[0003] In these filtration and drying apparatuses, a heat transfer surface for drying the powder product is usually provided on the side wall of the tank body, and a function of stirring the filter cake to promote the drying is provided. A stirring blade is also provided which has the function of scraping and discharging the powder product to a discharge port provided below the powder product.

Further, in these filtration and drying apparatuses, a discharge port for collecting the dried powder product is made to penetrate through a central portion or a peripheral portion of a filter medium / filter plate and a lower cover disposed at a lower portion of a tank body. And a filter provided on the lower side wall of the tank body located immediately above the filter medium.

In the latter conventional filtration / drying apparatus, a rotary shaft is provided vertically at the center of the tank body, and a plurality of blade arms provided with a scraping blade at the lower end of the rotary shaft. And the filter blade scrapes the filter cake.
While stirring, the loosened powder is sent in the outer circumferential direction toward the tank body side wall which is a heat transfer surface to promote drying, and the dried powder product is discharged from the discharge port provided in the tank body side wall. A configuration for collecting is adopted. The shape of the rotary blade in this filtration and drying apparatus is various, but the force in the rotational direction is made into a component force in the normal direction by the inclination angle of the scraping blade, and the loosened powder is directed in the outer circumferential direction toward the tank body side wall. The method of sending to is usually.

For example, Japanese Utility Model Laid-Open No. 5-67304 discloses that in the drying step, the powder product can be smoothly renewed on the heat transfer surface formed by the side wall of the tank body, and the drying efficiency can be improved. As shown in FIG. 5, a powder product having a structure capable of easily discharging the powder product later can be formed into a bell-shaped housing, having a slurry supply port 1 at an upper portion and a powder discharge port 2 at a lower side wall. A tank body 4 having a heating jacket 3 on the outer periphery of a side wall, a lower lid 8 having a filtrate discharge port 5 and provided at a lower portion of the body with a filter cloth 6 and a porous filter plate 7 supported in layers. And a plurality of plate-shaped scraping blades 10a attached to the lower end of the rotating shaft 9 and arranged to scrape and agitate the filter cake and send the filtered cake in the outer circumferential direction. A pair of wing arms 10, 10 projecting downward When, 1 for feeding the powder to the inner circumferential direction
A filter / drying device having a wing arm 11, 11 'having blade-shaped arms 11, 11' protruding from the outermost peripheral portion thereof with a plate-shaped recovery blade 11a facing downward.

However, the conventional filtration and drying apparatus shown in FIG. 5 has a complicated wing shape, so that it is difficult to clean the wings and to remove deposits and the like on the wings. Further, since the blade width is large, an excessive torque is generated at the time of cake scraping, and a large power is required. Furthermore, since the shape is complicated, man-hours for can manufacturing, welding, machining, etc. are large, and the manufacturing cost is high.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object a shape that is easy to clean, does not generate a large torque throughout the entire process, and has a low manufacturing cost. To provide a low filtration device.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to provide a tank body formed in a bell-shaped housing and having a slurry supply port, a filtrate outlet and a filter medium and a filter plate. A lower shaft provided at the lower portion of the main body in a layered manner, a rotating shaft vertically provided at the center of the tank main body, and a plurality of blade arms attached to the lower end of the rotating shaft for scraping and stirring the filter cake. And a blade arm of the stirring blade, wherein the blade arm of the stirring blade has a shape obtained by cutting a cylindrical tube obliquely along the axial direction of the tube. And a filter device characterized in that a shorter one of the arc-shaped end surfaces is fixed to a tip end and a longer one is fixed to a rotating shaft.

[0010]

[Function] The agitating blade consists of a wing arm having a simple shape obtained by simply cutting a cylindrical tube obliquely along the axial direction of the tube, so that the blade is easy to clean and removes deposits on the blade. It's easy to do. Further, since the shape of the wing arm is simple, no special processing is required and the manufacturing cost is reduced. Further, since the blade arm is round and the blade area at the tip is smaller than that on the fixed side, a large torque is not generated even when the stirring blade scrapes and stirs the cake.

[0011]

Embodiments of the present invention will be described below. FIG.
FIG. 6 is a longitudinal sectional view of the filtration device of the present invention, which is different from the filtration and drying device shown in FIG. 5 in that the rotating blades 12 are replaced with the stirring blades 13 of the present invention and the cleaning liquid pipe 1 provided with a nozzle 14a at the tip.
4 is arranged in the upper part in the tank main body, and the other parts are the same. Therefore, the same reference numerals are given and the description is omitted. 1
5 is a conduit, 16 is an inspection hatch, 17 is an opening / closing lid for discharging powder to the powder discharge port 2, 18 a is a driving device for rotating the rotating shaft 9, and 18 b is a driving device for moving the rotating shaft 9 up and down. It is a driving device. In this embodiment, a hydraulic cylinder is used as the driving device 18b. In the embodiment shown in FIG.
Although the powder outlet 2 is provided on the lower side wall of the tank body 4, the lower cover 8 may be provided with a powder outlet.

FIG. 2 is a view showing details of the stirring blade.
2A is a plan view showing a state where the stirring blade 13 is mounted on the rotating shaft 9, FIG. 2B is a front view of FIG. 2A, and FIG.
Is a blade arm 13 of the stirring blade 13 on the side attached to the rotating shaft 9.
It is a figure which shows the end surface of '. As shown in FIG. 2A, the stirring blade 13 is composed of three tapered blade arms 13 '. Each wing arm 13 ′ has a shape obtained by cutting a cylindrical tube obliquely along the axial direction, and the lengths of the arcs at both end surfaces are different. In this embodiment, as shown in FIG. 2C, the rotation shaft side end surface 13a having the longer arc length is used.
Set the arc length so that the center angle of the arc is 80 °,
The lower end of the blade arm 13 ′ of the stirring blade 13 has a horizontal plane of 30 °.
It is formed into an acute angle so as to form a corner, and has a structure advantageous for scraping a cake. The arc length of the other end surface 13b of the wing arm 13 'is shorter than the rotation shaft side end surface 13a, as shown in FIGS. 2 (a) and 2 (b).
The blade arm 13 ′ has a curved surface facing upward and has a tapered shape, that is, a blade area at the tip is smaller than that on the fixed side. In addition, the driving energy can be reduced.

A method of extracting solid particles in a raw material slurry in a dry powder state by the filtration device of the present invention thus configured will be described below in the order of each step.

[Filtering and Spreading] After the raw material slurry is fed and filled into the tank body 4 from the upper slurry supply port 1, the inside of the tank body 4 is pressurized with the gas supplied from the conduit 15, or the filtrate is discharged. The system is vacuumed and filtered. At this time, the filtrate that has passed through the filter cloth 6 on the porous filter plate 7 is collected outside the system from the filtrate outlet 5 provided in the lower lid 8. The solid content in the raw material slurry is deposited on the filter cloth 6 in a wet cake layer. In this filtration step, the stirring blade 13 is retracted above the cake layer. Eventually, after filtration for a certain period of time, the stirring blade 13 is slightly penetrated into the cake layer and rotated at a constant speed, and the water is discharged from the filtrate discharge port 5 so as to squeeze out water from the cake layer. This step is a so-called spreading step.

[Cake washing] Next, in order to wash foreign substances in the cake, the washing liquid is fed to the washing liquid pipe 14, and the washing liquid is sprayed onto the cake from the nozzle 14a at the tip, and the stirring blade 13 is moved to the inside of the cake layer. The foreign matter in the cake is discharged from the filtrate discharge port 5 together with the washing liquid while being fixed at a fixed position and rotating at a fixed speed.

[Scraping / Drying] The inside of the tank main body 4 is depressurized, and a heating medium is introduced into the heating jacket 3 to heat the side wall of the tank main body 4 and to move the stirring blade 13 upward and downward while rotating the stirring blade 13. The solid content deposited as a wet cake layer on the filter cloth 6 is:
While being scraped by the sharp lower end surface of the wing arm 13 ′, the wing arm 13 ′ is rotated and moved up and down while being uniformly mixed, and is dried by receiving heat from the heating jacket 3 on the side wall of the tank body 4. proceed. This step is a so-called scraping step.

When the drying of the solid content progresses to a certain degree, the height of the stirring blade 13 is fixed at a fixed position in the cake layer and rotated, and the drying is further advanced. Thus, when the powder product reaches a predetermined dry state, the inside of the tank body 4 is returned to the atmospheric pressure, the supply of the heat medium to the heating jacket 3 is stopped, and the drying step is completed.

In the present embodiment, the drying step is performed by using the heating jacket 3, but the present invention can be applied to a filtration device that does not perform drying.

[Discharge] Then, while rotating the stirring blade 13 near the bottom of the tank body 4, the opening / closing lid 17 of the powder discharge port 2 is opened.
Is opened, and the dried powder product is collected outside the system through the powder discharge port 2.

According to the filtering device of the present invention, the wet powder is filtered and dried in the above-mentioned steps. However, the rotational torque during the filtering and drying operation of the device of the present invention is reduced by a conventional type of filtering device. A simulated experiment was performed for comparison with the rotational torque during the drying operation, and will be described below.

The simulation device has a configuration as shown in FIG. Referring to FIG. 2, a motor 20 with a speed reducer is provided at the head of a frame 19, an air cylinder 21 is attached to a lower portion of the frame 19, and a guide bar 22 is connected to a rod 21a of the air cylinder 21. 22 is fixed rod 2
It is possible to go up and down along 3. Guide bar 22
Is fixed to an elevating table 24, and an experimental tank 25 is connected to the elevating table 24. 26 is a wet powder (slurry) and 27 is a filter cloth. The motor 20 is connected to a rotating shaft 29 via a belt 28, and the stirring blade of the present invention (having the configuration shown in FIG. 2) or the stirring blade of the comparative example is fixed to the tip of the rotating shaft 29. As shown in FIG. 6, the stirring blade of the comparative example has two blades 30a protruding downward from each of three blade arms 30. As shown in FIG. According to the simulation device of FIG. 3 configured as described above, the experimental tank 25 can be moved up and down together with the guide bar 22 while being guided by the fixed rod 23 by extending and contracting the rod 21a.

The inside diameter of the experimental tank 25 is 500 mm and the height is 4 mm.
The outer diameter of the stirring blade was 480 mm, and the filter cloth 27 was attached at a position 100 mm from the bottom of the experimental tank 25. Then, a torque detector was attached to the rotating shaft 29, and the rotating torque in each of the following steps was measured.

The experimental method does not always correspond to the actual process order for the sake of convenience of the experiment, and the contents simulate the operation in the actual machine. It will be described sequentially.

[Cake Washing] The slurry used in the experiment was obtained by mixing 40 kg of calcium carbonate powder with 40 kg of water. The experimental tank 25 was fixed at a position where the height of the stirring blade was 10 mm higher than the filter cloth 27, and the rotation torque of the rotation shaft 29 was set to 10 rpm or 30 rpm, and the rotation torque was measured. The height of the liquid surface at this time was about 2
The height was 50 mm. The calcium carbonate powder has a bulk density of 1.4 g / cm ³ and an average particle size of 300 μm.

[Spreading] The water in the slurry used for washing is filtered through the opening 31 under a reduced pressure of 500 mmHg for a certain period of time. When the experimental tank 25 is fixed at a position where the height of the stirring blade is 20 mm lower than the upper surface of the wet cake layer while rotating at a rotation speed of 10 rpm, the experimental tank 25 is moved at that position at a speed of 5 mm / min or 10 mm / min. The rotational torque was measured for each case of lifting and lowering. In this case, the height of the cake layer was about 90 mm.

[Scraping] In the same manner as in the above spreading step, while using the wet cake after filtration under reduced pressure, while rotating the rotating shaft 29 at a rotation speed of 10 rpm, the height of the stirring blade is 52 mm from the upper surface of the wet cake layer. When the experiment tank 25 is fixed at a lower position,
The experimental tank 25 was fixed at that position when the experimental tank 25 was raised and lowered at a speed of 5 mm / min, 10 mm / min or 20 mm / min, and at a position where the height of the stirring blade was 85 mm below the upper surface of the wet cake layer. In that case, the experimental tank 25 was
The rotational torque was measured for each of the cases of raising and lowering at a speed of min, 10 mm / min or 20 mm / min. In this case, the height of the cake layer was about 90 mm.

[Drying] 30 kg of the above-mentioned calcium carbonate powder was put into the experimental tank 25, and then 2 kg of water was added in four portions (in order to more closely resemble the state of the actual drying step), and the height of the stirring blade was raised. The experimental tank 25 is fixed at a position where the height is 10 mm higher than the filter cloth 27, and the rotating shaft 29 is rotated at a rotation speed of 10 rpm. Was measured.

[Discharge] Only 30 kg of the above calcium carbonate was put into the experimental tank 25, and the height of the stirring blade was 1
The experimental tank 25 is fixed at a position higher by 0 mm, and the rotating shaft 29
Was rotated at a rotation speed of 10 rpm, and the rotation torque was measured.

The results of the above torque measurement are shown in Table 1 below.

[0030]

[Table 1]

As is clear from Table 1, the present invention has a small variation in torque over the entire process and no large torque is generated. However, the comparative example has a large fluctuation in the torque, and particularly requires twice or more the torque of the present invention in the scraping, drying and discharging steps, and requires an extremely large torque in the scraping and drying steps. In the spreading and cake washing steps, the torque of the present invention is slightly higher than that of the comparative example, but the difference is small. Overall, the stirring blade of the present invention is an excellent stirring blade with reduced torque. You can see that there is. In both of the present invention and the comparative example, it can be seen that the elevating speed does not significantly affect the change in the rotational torque.

FIG. 4 is a diagram extracted from the data of Table 1, and ○ indicates a numerical value of the present invention, and Δ indicates a numerical value of a comparative example. In addition, the rotation torque when the elevating speed of the experimental tank was 10 mm / min during the spreading, and the scraping blade was raised and lowered at a speed of 10 mm / min at a position where the stirring blade was 85 mm below the upper surface of the wet cake layer during the scraping. The rotational torque in the case is shown.

[0033]

As described above, the present invention has the following advantages. Since the stirring blade is formed of a blade arm having a simple shape obtained by simply cutting a cylindrical tube obliquely along the axial direction of the tube, the washing performance of the stirring blade is improved. Since the shape of the wing arm is simple, no special processing is required and the manufacturing cost is reduced. Since the blade arm is rounded and the blade area at the tip is smaller than that on the fixed side, a large rotating torque is not generated even when the cake is scraped by the stirring blade, and the driving energy can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a filtration device of the present invention.

2 (a) is a plan view showing a state where the stirring blade of the present invention is mounted on a rotating shaft, FIG. 2 (b) is a front view of FIG. 2 (a), and FIG. It is a figure which shows the end surface of the blade arm of the stirring blade of this invention of the side attached to the shaft.

FIG. 3 is a side view of an apparatus used for a simulation experiment of a filtration drying step.

FIG. 4 is a diagram showing a change in rotation torque during a simulation experiment of a filtration drying process.

FIG. 5 (a) is a longitudinal sectional view of a conventional filtration and drying apparatus,
FIG. 5B is a cross-sectional view thereof.

FIG. 6 (a) is a plan view showing a state where a stirring blade of a comparative example used in a simulation experiment of a filtration drying process is mounted on a rotating shaft, and FIG. 6 (b) is a drawing of a stirring blade of the comparative example. It is a side view of the state attached to the rotating shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Slurry supply port 2 ... Powder discharge port 3 ... Heating jacket 4 ... Tank body 5 ... Filtrate discharge port 6 ... Filter cloth 7 ... Porous filter plate 8 ... Lower lid 9 ... Rotating shaft 13 ... Stirring blade 13 '... Blade arm

Continuation of the front page (56) References JP-A-2-187102 (JP, A) JP-A-2-187101 (JP, A) JP-A-61-21708 (JP, A) JP-A-6-277411 (JP) JP-A-5-103919 (JP, A) JP-A-57-56006 (JP, A) JP-A-1-184008 (JP, A) JP-A-5-67304 (JP, U) (58) Surveyed field (Int. Cl. ⁶ , DB name) B01D 29/00-29/48

Claims (1)

(57) [Claims] 1. A tank body formed in a bell-shaped housing and having a slurry supply port, a lower lid having a filtrate discharge port and provided at a lower portion of the body with a filter medium and a filter plate supported in layers, A rotating shaft vertically provided at the center, a stirring blade attached to a lower end portion of the rotating shaft and having a plurality of blade arms for scraping and stirring the filter cake, and a powder discharge port were provided. In the filtration device, the blade arm of the stirring blade has a shape obtained by cutting a cylindrical tube obliquely along the axial direction of the tube, and the shorter arc length of the arc-shaped end faces is closer to the distal end. A filter having a longer arc length fixed to a rotating shaft.