JPS60244301A - Centrifugal thin film dryer - Google Patents

Abstract

PURPOSE:To reduce the abrasion of a rotary blade and the inner surface of an external cylinder, by making it possible to adjust the rotary blade in a centrifugal thin film dryer so as to bring the same to the contact or non-contact state with the inner surface of the cylinder corresponding to the number of rotations. CONSTITUTION:A solution to be treated is introduced into a cylinder 2 from a supply port 6 and the powder in the solution is adhered to the inner surface of the cylinder 2 in a thin film form by centrifugal force due to the rapid rotation of a rotary shaft 4. The thin film is dried by the heat of an outside steam jacket 1 and further fallen in a lower hopper 7 while scraped off by the rotation of rotary blades 3 when said thin film is formed, the leading end of each rotary blade 3 is separated from the inner surface of the cylinder by the centrifugal force due to the rotation of the blades 3 and the resultant moment of the springs 10 provided to one ends of the blades 3 and abrasion caused by the contact of both of them is prevented. When the thin film is scraped off from the inner surface of the cylinder, the number of rotations are adjusted to bring the leading ends of the blades 3 into contact with the inner surface of the cylinder to perfectly scrape off the powder thin film. Because the leading ends of the blades are brought into contact with the inner surface of the cylinder only when the membrane is scraped off, abrasion by the friction between both of them is reduced.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a centrifugal thin film dryer used in chemical plants and nuclear waste liquid treatment equipment, and in particular to scraping off powder adhering to the inner wall of the centrifugal thin film dryer. This invention relates to a structure that reduces wear on the blades and walls that carry out this process.

[Background of the invention]

A centrifugal thin film dryer is generally vertical, and as shown in Figure 2, there is a cylinder 2 covered with a steam jacket 1, a rotating shaft 4 attached to the center of the cylinder 2, and radially attached to the rotating shaft 4. It is comprised of blades 3, an electric motor 5 that rotates a rotating shaft 4, a processing liquid supply port 6, a lower hopper 7 that receives the powder scraped by the blades 3, and the like.

Processing liquid (waste liquid, etc.) supplied from the processing liquid supply port 6
As the blades 3 attached to the rotating shaft 4 rotate, the material is spread in a thin film form on the wall surface 2 by centrifugal force, and is heated in the steam jacket 1 to be dried and powdered. The dry powder is scraped off from the cylindrical wall surface 2 by the blades 3 and falls into the lower hole 7.

The relationship between the blade 3 and the cylindrical wall surface 2 is shown in FIG. 3, which is a horizontal sectional view.
Two types as shown in FIG. 4 are conventionally common. In FIG. 3, a gap is provided between the blade 3 and the cylindrical wall surface 2 to scrape off powder that has adhered to a certain amount or more. Fig. 4 shows that when the shaft 4 rotates clockwise, the blades 3 are pressed against the wall surface 2 by centrifugal force using the pin 8 as a fulcrum, and the blades 3 are constantly rotated in contact to completely scrape off the powder. This is what I did.

In the structure shown in FIG. 3, since the blade 3 and the wall surface 2 do not come into direct contact with each other, there is an advantage that wear of the blade 3 and the wall surface 2 can be prevented. However, it is not possible to remove powder or processing liquid that has adhered below the gap between the blade 3 and the wall surface 2, and the heat transfer from the wall surface 2 is reduced, resulting in a decrease in the evaporation rate of the processing liquid and a reduction in the processing capacity. . In order to increase the processing capacity, it is possible to increase the heating temperature of the wall surface 2, but this is disadvantageous in terms of equipment, such as increasing the size of the heating equipment and increasing thermal deformation of the wall surface 2. In addition, when cleaning and removing the powder adhering between the blade 3 and the wall surface 20, the cleaning liquid is indirectly blown onto the powder by centrifugal force, so there is a drawback that it takes time to completely remove the powder. have.

In the structure shown in FIG. 4, since the blade 3 and the wall surface 2 constantly rotate in contact with each other, there is almost no decrease in processing capacity due to the decrease in heat transfer, and even during cleaning, the blade 3 is forced to rotate. Since it can be removed by washing, cleaning time is also reduced. However, constant contact causes wear of the blades 3 and wall surface 2, which poses a major maintenance problem.

[Purpose of the invention]

The present invention has been made in an attempt to improve the above-mentioned drawbacks.
The purpose of this is to create a centrifugal thin film dryer that can operate with less wear by creating a gap between the blades and the wall during normal operation, and that allows the blades to come into contact with the wall during cleaning for efficient cleaning. It is about providing.

[Summary of the invention]

The feature of the present invention is that the blades are rotatably attached to the rotating body inside the cylinder of the centrifugal thin film dryer, and the blades are rotatably mounted using the centrifugal force of the blade itself. It has a structure in which the selection of contact and non-contact states between the blades and the wall surface can be adjusted depending on the rotational speed.

This reduces wear on the blades and walls, extends their lifespan, and enables efficient cleaning operations.

[Embodiments of the invention]

The present invention will be explained in detail below.

FIG. 1 is a cross-sectional top view of a centrifugal thin film dryer according to an embodiment using a compression spring. FIG. 5 is a view seen from the entrance direction of FIG. 1. FIG. 6 is an explanatory diagram of its operation.

Components that are the same as those of the conventional example are indicated by the same reference numerals.

In these figures, the blade 3 is supported rotatably around pin 8 with respect to a support frame 11 attached to a rotating shaft 4, and a compression spring lO is attached to the inner circumference side of the blade with the pin 8 as the boundary. 3
and the plate 14 attached to the support 7 frame 11 to apply a force Fk to press the wing 3 against the wall surface. Further, the weight of the inner circumferential side 3a and the outer circumferential side 3b of the blade 3 with the pin 8 as a boundary are configured to generate a rotational force that rotates the blade 3 in a direction away from the wall surface 2 due to the centrifugal force acting on them. It is. That is, as the rotating shaft 4 rotates, the centrifugal force F1 generated on the inner peripheral side 3a of the blade 3 is larger than the centrifugal force F; generated on the outer peripheral side 3b. The mounting position of the spring 10 and its spring force Fk1, as well as the weight and center of gravity position of the inner peripheral side 3a of the blade 3, are determined so as to balance the rotational force of the blade 3 around the pin 8 due to the centrifugal force at the set rotation speed. The weight and center of gravity position of the outer peripheral side 3b are determined in advance. In addition, since the blade 3 separates from the wall surface 2 at a rotation speed higher than the set rotation speed, a stopper 9 is required to keep the gap between the blade 3 and the wall surface 2 constant.
is provided in Great 14.

According to this configuration, by setting the rotation speed above the set rotation speed as the normal operating range, the blade 3 and the wall surface 2 are operated with a certain gap during normal operation, and wear can be prevented.

Further, if the cleaning operation is performed at a rotation speed below the set rotation speed, the blades 3 rotate while being pressed against the wall surface 2, so that cleaning can be performed in a much shorter time than in a cleaning operation in which a gap is maintained.

Hereinafter, the force relationship acting on the blade 3 will be explained in detail based on FIG. 6. The codes used are as follows: O mi Weight of inner peripheral side 3a of blade 3 (klil) m; Blade 3
Weight of the outer circumferential side 3b (kg) R1 Radius of rotation of the center of gravity of the inner circumferential side 3a of the blade 3 (m) R2i Radius of rotation of the center of gravity of the outer circumferential side 3b of the blade 3 (m) θi Center of gravity of the inner circumferential side 3a of the blade 3 Angle (degrees) between the center of gravity of the blade 3 and the center of rotation 4 and the pin 8 (degrees) θ5 Angle (degrees) between the center of gravity of the outer circumferential side 3b of the blade 3 and the center of rotation 4 and the pin 8 θ, direction of force by the compression spring 10, and center of rotation 4 and the line connecting the pin (degrees) δ5 Initial angle of blade 3 (when the blade is pressed against wall 2)
(degrees) F, centrifugal force acting on the inner circumferential side 3& of blade 3 (kliJ) F6
Centrifugal force (kg) Fb acting on the outer peripheral side 3b of the blade 3
The force (kg) that the outer peripheral end of the blade pushes against the wall 2 (kg) Fk The force (kg) t exerted on the blade 3 by the spring 10, the distance between the center of gravity of the inner peripheral side 3a of the blade 3 and the pin 8 (m) t6 of the blade 3 Distance between the center of gravity of the outer circumferential side 3b and pin 8 (m) Lk Distance between the mounting position of spring 10 and pin 8 (m) tb
Distance (-)K between the outer peripheral edge of the blade 3 and the pin 8 Spring constant (
kg7m) Displacement (initial displacement) of spring 10 in δ (m) δ1 Spring 10
Displacement (displacement of spring 10 until stop 49 recovers [3]) (m) N Number of rotations (rpm) ω Angular velocity ω = (2πN)/60 (rad/see
) g Gravitational acceleration (9.8 m/s2) M, moment in the direction of pressing the blade 3 against the wall 2 (R
19・m) ML Moment in the direction of separating the blade 3 from the wall 2 (kg・
m) Each dimension and angle in the position of the stop/f9 shall be indicated with a '.

When the rotational speed is N, the force applied to the center of gravity of the inner circumferential side 3m and the outer circumferential side 3b of the blade 3 is expressed as F1=(m17g)R1・ω2. Fδ=(m67g)・
To consider the R6・ω2 balance equation, consider the monument of pin 8 times, MR=Frcotθ6−1−, −cowθb+δ−11COsθ+tkIICO8θbML=Fi+co
IIe1-4iacosθb.

When the rotation speed is O, FH* Fl is O, so MR=
δ to 4KII cos θ to 'tk' e Ol! θbM
When L=0, the blade 3 is pressed against the wall surface 2 with a moment corresponding to MR.

If the weight of each dimension is determined so that Mn'' ML at the set rotation speed N, that is, ω.=2πN0/60 (
m,;/g)・R6φω. ``eosθ-・l-・cos
θb 0 +δ to +KCO8θ−tkjCOIIθb=(m1/
g)・R1−ω. If it is determined to satisfy 2・cOaθ1”t1'e08θb, MR<
ML, below the set rotation speed, M > ML.

Next, at the moment when the wing 3 leaves the wall 2 and stops when it hits the strut 4-9, the displacement of the spring is δ, +δ8. ) (m, /g) 'R5'-ω2・cosθ5′・08θb′+(δ10δgt)K*eosθ′・tk
-cosθb'=(town/g)・RI"4"'eo! 1I
91'41 Ncosab', which is about 9 matches. That is, Fi'=(m1/g)・R5'・ω2・F5'=(m,
, /g)・R, ;′・ω2, MR′=F, ;′ aosθo ” t5 ′ (40
8θb′+ (10δ8t for δ)・@cosθ′・t
kaco8θb1ML' =F 1' ・c O!
This is when MR'=ML' with lθI'et1 rumor cosI9b'.

From about 9 matches above When MR≧ML, the blade 3 contacts the wall surface 2.

In MR(M, (M,'), the blade 3 is away from the wall 2 and does not hit the strut f -9.

When M,'<ML, the wing 3 is separated from the wall 2 by the stopper 9.
There is a certain gap between the contact wall surface 2 and the wall surface 2.

By controlling the above state using the angular velocity ω, that is, the rotational speed N, it is possible to operate the blade 3 and the wall surface 2 with a constant gap or in contact with each other.

Figure 7 shows the relationship between the right-handed moment MR and the rotation speed, Figure 8 shows the relationship between the left-handed moment ML and the number of rotations, and Figure 9 shows the difference between the right-handed moment and the left-handed moment and the number of rotations. FIG. 10 shows the relationship between the gap between the blade 3 and the wall surface 2 and the rotation speed.

FIG. 11 shows another embodiment. In this embodiment, the compression spring 10 and the strut spring 9 shown in FIG. When the rotation speed is higher than the set rotation speed, it separates from the wall surface 2, and when the rotation speed is lower than the set rotation speed, it comes into contact with the wall surface 2.

FIG. 12 shows another embodiment. Figure 13 is the same as Figure 12.
It is a figure seen from the direction. 1jL3 has a long hole 13 on the inner circumferential side of the bottle 8 with an ascending slope toward the outer circumference.
A balance weight 12 is incorporated therein so that it can be rotated along it. Also, the inner circumferential side of the blade 3 is affected by centrifugal force.
/J It is bent at an angle that allows the run weight 12 to move in the outer circumferential direction and in the opposite direction to the rotation direction.

A stop 9 is provided on the outer periphery of the support frame 11 to limit the amount of gap between the blade 3 and the wall surface 2. The angle of the elongated hole 13 is such that the balance weight 12 can only rise when the number of revolutions exceeds the set rotation speed. The operation of this embodiment will be explained in detail below with reference to FIGS. 14 and 15.

FIG. 14 shows the situation of centrifugal force acting on the inner circumferential side 3a and outer circumferential side 3b of the blade 3 and the balance weight 12 when the balance weight 12 is at the lowest point of the elongated hole 13 when the rotation speed is below the set rotation speed, FIG. 15 shows a case where the balance weight 12 is at the highest point of the elongated hole 13 when the rotation speed is higher than the set rotation speed. Below the set rotation speed, the centrifugal force Fc generated in the balance weight 12 as shown in Fig. 14 acts as a force in the direction of turning the blade 3 clockwise, that is, pressing the blade 3 against the wall surface 2, and above the set rotation speed. As shown in FIG. 15, it acts as a force in the direction of turning the blade 3 to the left, that is, moving the blade 3 away from the wall surface 2.

As a result, depending on the rotational speed of the rotary shaft 4, the blade 3 and the wall surface 2 can be operated with a constant gap or in contact or non-contact.

Next, still another embodiment is shown in FIG. In this figure, unlike in Figure 1, the spring 1o is stretched and attached in advance as a tension spring, and a force Fk is applied in the direction of separating the blade 3 from the wall surface 2. Centrifugal force F
, are configured to be smaller than the centrifugal force F6 acting on the outer peripheral side 3b. Therefore, using the same symbols as in the explanation of Fig. 1', MR-FrCO8θ, ;-2δ8cosθbM
L=p, HeOJlθ1IIt1・coBθb+δ・K11coIIθ=tkcosebMR'=F5
'・co@θ,;"z2B'cosθb'ML'=F1
'cos θ, 'mAia cos θb' + (10 δ5t for δ
)K*cosθk''tk' e Oa 19 b'. MRI ML shows the state where the blade 3 and the wall surface 2 are in contact in Fig. 1, and MB' + ML' shows the state where the blade 3 and the stopper 9 are in contact. However, in this example, MR and ML are the state where the blade 3 is in contact with the cyst collar 9 due to the spring 10, and Mn' + ML' is the state where the blade 3 is in contact with the wall surface 2 due to centrifugal force. Indicates a state of contact.

Therefore, when ML>MR, the blade 3 hits the stop 49 and has a constant gap from the wall surface 2.

When ML<MR<MR', the blade 3 is away from the stopper 9 and does not come into contact with the wall surface 2 either.

MR' In MR, the blade 3 contacts the wall surface 2.

By controlling the above-mentioned state with the rotational speed N, it is possible to operate the blade 3 and the wall surface 2 with a constant gap or in contact with each other or without contact. That is, non-contact constant gap operation is possible below the set rotation speed, and contact operation is possible above the set rotation speed.

FIG. 17 shows a modified embodiment of FIG. 16. In this embodiment, a tension spring 10 which is an elastic body shown in FIG.
The stopper 9 is provided on the outer peripheral side of the support frame 11, and the operation is the same as that of the embodiment shown in FIG.

FIG. 18 shows another embodiment using a shiftable weight.

FIG. 19 is a view of FIG. 18 from A. The blade 3 has a long hole 1 which has an upward slope from the inner circumferential side to the outer circumferential side from the pin 8.
3, and a balance weight 12 that can be rolled along the elongated hole 13 is incorporated therein. Further, on the outer circumferential side of the support frame, there is provided a strut horn f9 that keeps the gap between the blade 3 and the wall surface 2 constant. The angle of the elongated hole 13 is such that the balance weight 12 can move up through the elongated hole 13 only when the number of rotations exceeds the set rotation speed.

In this embodiment, the balance weight is 12 below the set rotation speed.
is the lowest point of the groove 13, t, b is on the innermost side, and at this time, the centrifugal force acting on the balance weight 12 rotates the blade 3 counterclockwise.
In other words, the wing 3 is pressed against the strut horn 49, and the wing 3 and the wall surface 2 are
When the rotation speed exceeds the set rotation speed, the balance weight 12 rises within the groove 13 and reaches the highest point, that is, the outermost side, and at this time it acts on the balance weight 12. The centrifugal force is configured to act on the blade 3 in a clockwise direction, that is, in a direction that presses the blade 3 against the wall surface 2. This allows non-contact constant gap operation below the set rotation speed, and contact operation above the set rotation speed.

As explained above, it is possible to have an embodiment in which contact occurs below the set rotation speed and non-contact occurs above the set rotation speed, and, conversely, an embodiment in which contact occurs below the set rotation speed and contact occurs above the set rotation speed. However, in any case, normal operation is in a non-contact state,
By keeping the stone in contact during the cleaning operation, it is possible to prevent wear on the blades and the cylindrical wall and to perform efficient cleaning.

〔Effect of the invention〕

According to the present invention, rotation speed control, non-contact constant gap operation with less wear on the blades and cylindrical wall surface of the centrifugal thin film dryer,
Efficient cleaning operation with the blades and wall in contact is possible, extending life and shortening operating time.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional view of an embodiment of the present invention, Fig. 2 is an overall vertical cross-sectional view of a centrifugal thin film dryer, and Fig. 3 is a conventional example having a fixed gap between the fixed blade and the wall surface. 4 is a cross sectional view of a conventional example of a movable wing structure, and FIG. 5 is a cross sectional view of A of FIG. 1.
6 is an explanatory diagram of the operation of the embodiment shown in FIG. 1, FIGS. 7 to 10 are graphs showing the operation of the embodiment, and FIG. 11 is a diagram showing another embodiment of the present invention. FIG. 12 is a partial cross-sectional view of the example, FIG. 12 is a partial view of another embodiment, and FIG.
2, as seen in the A direction, FIGS. 14 and 15 are explanatory diagrams of the operation of the embodiment in FIG. 12, and FIGS. 16, 17, and 18 are partial views of other different embodiments. , Figure 19 is A of Figure 18.
It is a view seen in the direction. 1: Steam jacket 2: Cylindrical wall surface 3: Wing 4: Rotating shaft 8: Bottle 9: Stopper 10: Spring 11: Support frame 12: Balance weight 13: Long hole 14: Plate p0 I#↑1 Tato p0 in Figure 1 11 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 16 Figure 17

Claims (1)

[Claims] 1. A cylindrical container into which a processing liquid is supplied and whose wall surface is heated; a support frame that rotates around the center line of the cylindrical container; In a centrifugal thin film dryer comprising blades for scraping powder generated by formation and evaporation of a thin film of the processing liquid, the blades are attached to a support frame so as to be rotatable about an axis parallel to the center line of the cylindrical container, and A control member is provided to apply a control force to the blade, and due to the sum of the centrifugal force acting on the blade itself due to rotation of the support frame and the control force with respect to the axis, the rotation speed of the support frame is equal to or higher than the set rotation speed. The centrifugal thin film is characterized in that the blades are brought into contact with or separated from the inner surface of the wall surface depending on whether the blades are in contact with or separated from the inner surface of the wall surface, and further comprising a stopper for limiting the amount of separation of the blades from the wall surface. Dryer. 2. The centrifugal thin film dryer according to claim 1, wherein the blades contact the wall surface when the rotation speed of the support frame is equal to or higher than a set rotation speed, and are separated from the wall surface when the rotation speed is lower than the set rotation speed. 3. The centrifugal thin film dryer according to claim 1, wherein the blade separates from the wall surface when the rotation speed of the support frame is above a set rotation speed, and comes into contact with the wall surface when the rotation speed is below. 4. The centrifugal thin film dryer according to claim 1, 2 or 3, wherein the control member is a spring suspended between the support frame and the blade. 5. The centrifugal device according to claim 1, 2, or 3, wherein the control member is a balance weight attached to the blade and movable relative to the blade due to centrifugal force. Thin film dryer.