JPH0734879B2 - Centrifuge for liquid-liquid separation - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal separator for liquid-liquid separation.

[0002]

2. Description of the Related Art An apparatus for separating a mixed solution of two kinds of liquids having different specific gravities (hereinafter referred to as "stock solution") by using centrifugal force is
Various proposals have been made, but the following two models are typical examples. The first example is a de Laval centrifuge.
This is a method in which the stock solution is supplied to a rotor formed by stacking and mounting a large number of separation plates in the shape of a vertical shaft on a vertical rotary shaft with a constant gap, and the amount of the stock solution to be processed is reduced. If a large number of separators are required and the number of separators is increased to make the cylinders longer, it will be difficult to evenly distribute the concentrate between separators. Since it is a support, there is a problem that it is not suitable for a large machine because of its difficulty in strength design.

The second example is a screw type decanter. This is to centrifuge the undiluted solution with a rotating body consisting of a long cylinder supported by a horizontal rotating shaft and a screw conveyor that is coaxially mounted inside and rotates at a slight speed difference. The liquid is separated to the outer diameter side in the radial direction, and the light liquid moves to the inner diameter side in the radial direction and is withdrawn from the end of the rotating body, respectively. However, there is a problem that the separation accuracy is low in order to separate a liquid having a small difference in specific gravity even though it is suitable for the above. In addition, there is a problem that extra equipment such as a screw conveyor and a differential speed rotating mechanism for separating a liquid containing no solid content is provided.

[0004]

The present invention has been made in view of the above problems of the prior art, and utilizes a large settling area and centrifugal force for a mixed liquid of two kinds of liquids having different specific gravities. It is an object of the present invention to provide a centrifugal separator for liquid-liquid separation, which is capable of efficiently and highly accurately separating, and is suitable for treating a large amount of mixed liquid.

[0005]

[Means for Solving the Problems] First to solve the above problems
The gist of the invention is that in a centrifugal separator that separates a mixed liquid of liquids having different specific gravities into heavy liquid and light liquid by using centrifugal force, the left and right shafts (2, 3) respectively support the shaft. A horizontal rotary cylinder (1) and a vertical separation plate radially fixed to the peripheral surface of a separation plate shaft (6) mounted on the axial center of the rotation cylinder at a predetermined angle with the radial direction. (5), a disk-shaped weir plate (8) coaxially mounted in the right shaft portion (3) of the rotating drum and integrally formed at the inner end, and an opening at the outer end. And a light liquid pipe (7) fixed to the right end of the separation plate shaft.
And means (10) for adjusting the opening of the heavy liquid outlet opening (4) at the end of the right shaft of the rotary cylinder, and the light liquid pipe outlet opening and the light liquid outlet (18) are liquid-tightly sealed. The rotary joint (9), the opening of the left shaft portion (2) of the rotary drum, and the stock solution inlet (1
6) Liquid-tight rotary joint (1
4) and a heavy liquid chamber (23) having a heavy liquid outlet (17) that liquid-tightly surrounds the heavy liquid opening (4) at the end of the right shaft portion, and the liquid-liquid separation is provided. A centrifuge for use in a second aspect of the present invention, which is based on a measuring device (20) mounted on a light liquid conduit (24) for measuring pressure and an output signal of the measuring device. The centrifugal separator for liquid-liquid separation according to the first aspect of the present invention, characterized in that the centrifugal separator for liquid-liquid separation is provided with a controller (21) for controlling the adjusting means (15).

[0006]

The stock solution introduced from the stock solution inlet 16 enters the separation zone in the rotary cylinder 1 via the hollow portion of the left shaft portion 2 of the rotary cylinder. In the separation zone, a plurality of vertical separation plates 5 are radially arranged on the outer peripheral surface of the separation plate shaft 6 at a predetermined angle with the radial direction. The undiluted solution flows axially between the longitudinal separation plates 5, but the heavy liquid component collides with the separation plate under the action of centrifugal force and then moves along the separation plate toward the outer diameter side. On the other hand, the light liquid component moves to the inner diameter side, and forms a liquid layer at the outlet of the separation zone. The heavy liquid component overflows the outer peripheral portion of the disk-shaped dam plate 8, flows out from the opening 4 through the heavy liquid passage 19, and is discharged from the heavy liquid outlet 17 to the outside of the machine. On the other hand, the light liquid component passes between the downstream end of the vertical separation plate 5 and the dam plate 8 and flows out to the connected pipe line outside the machine via the light liquid pipe 7, the rotary joint 9 and the light liquid outlet 18. To do. Since the position of the interface between the heavy liquid and the light liquid in the separation zone can be adjusted by the pressure of the light liquid, this pressure is measured by the measuring device 20, and the adjusting means 15 is controlled by the controller 21 so that the pressure becomes a predetermined value. . When the composition of the stock solution has changed drastically, by changing the set value of the controller 21, the interface position between the heavy solution and the light solution can be maintained at an appropriate position, and high-precision separation can always be performed. .

[0007]

Embodiments will be described below with reference to the drawings. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is A of FIG.
It is a transverse cross-sectional view of -A view. In the figure, reference numeral 1 denotes a rotary drum horizontally supported by bearings at left and right shaft portions (2, 3), and driven by an electric motor (not shown) via a pulley 22 fitted to the left shaft portion 2. To be done. Reference numeral 5 denotes a plurality of longitudinal separation plates that are axially long and fixed radially to the outer peripheral surface of a separation plate shaft 6 that is mounted on the shaft center of the rotary cylinder 1 at a slight angle S with the radial direction. Is. As a method for fixing the longitudinal separating plate, the longitudinal separating plate may be inserted into the narrow groove of the separating plate shaft 6 and welded, or the structure proposed by the applicant in Japanese Patent Application No. 63-270966 previously. Good.

Reference numeral 7 denotes a light liquid pipe coaxially provided in the hollow portion of the right shaft portion 3, and a disc-shaped dam plate 8 is integrally formed at the inner end thereof to form the right end of the separation plate shaft 6. It is fixed to the via a mounting member. A rotary joint 9 is provided at the outlet opening of the light liquid pipe 7, and the rotating light liquid pipe 7 and the fixed-side light liquid outlet 18 are liquid-tightly connected by a mechanical seal or the like by a sealing mechanism (not shown). ing. Reference numeral 10 denotes a coma dam that is attached to the outer surface of the middle portion of the light liquid pipe 7 so as to be movable back and forth, and that is provided facing the heavy liquid opening 4 of the right shaft portion 3 and that adjusts the opening area.

Reference numeral 11 denotes a cylindrical casing that surrounds the rotary cylinder 1, and has end plates (12, 1) at its left and right ends.
3) are attached by screwing. Reference numeral 14 denotes a rotary joint provided at the stock solution inlet, and a seal mechanism (not shown) connects the stock solution inlet 16 on the fixed side and the end opening of the rotating left shaft 2 in a liquid-tight manner by a mechanical seal or the like. Reference numeral 20 denotes a pressure detection measuring device mounted on the light liquid conduit 24, and 15 denotes a pressure control valve controlled by the controller 21 based on the output of the measuring device 20.

The operation of the embodiment having the above construction is as follows. The stock solution introduced from the stock solution inlet 16 flows into the separation zone in the rotary drum 1 through the hollow portion of the left shaft portion 2 via the rotary joint 14. The undiluted solution flows axially between the longitudinal separating plates 5 arranged radially, but the heavy liquid component having a large specific gravity moves to the outer diameter side in the radial direction along the separating plate 5 under the action of centrifugal force. On the other hand, the light liquid component moves to the inner diameter side, and forms a heavy liquid layer H and a light liquid layer L at the outlet of the separation plate 5. The heavy liquid layer H enters the heavy liquid passage 19 through an annular portion between the outer circumference of the disk-shaped dam plate 8 and the inner circumference of the rotary drum 1, and enters the gap between the end opening 4 of the right shaft portion 3 and the dam 10. It is discharged into the heavy liquid chamber 23 and discharged from the heavy liquid outlet 17 to the outside of the machine. On the other hand, the light liquid L enters the light liquid pipe 7 from between the right end portion of the separation plate shaft 6 and the dam plate 8,
It is delivered by being controlled by the control valve 15 via the rotary joint 9 and the light liquid outlet 18.

Next, the operation control method of the above embodiment will be described. In the separation zone in the rotary cylinder 1, the respective pressures at the interface positions of the heavy liquid and the light liquid are determined by the following mathematical formulas 1 and 2.

[Equation 1]

[Equation 2] Here, R is the radius from the center of the rotary cylinder 1 to the interface, r is the radius from the center of the rotary cylinder to the outer diameter of the light liquid pipe 7, γL and γH are the densities of the light liquid and the heavy liquid, PL and PH, respectively. Are the pressures at the outlet openings of the light liquid and the heavy liquid, respectively, and ω is the rotation speed of the rotating drum. Here, when the radius r of the light liquid pipe 7 is smaller than the radius R of the interface, the following Formula 3 holds for the interface radius R from Formulas 1 and 2.

[Equation 3] In order to improve the accuracy of separation of the light liquid and the heavy liquid in the separation zone, it is necessary to maintain the interface position at an appropriate position on the inner diameter side of the dam plate 8. For example, when the density γL of the light liquid becomes small in the mathematical expression 3, to maintain R at the same value, PL
It is necessary to increase the set pressure in the measuring device 20 by the controller 21.

For example, when separating a mixed liquid of water and oil,
When the interface moves from the outer periphery of the barrier plate 8 to the outer diameter side, oil content is mixed into water (heavy liquid), and thus the physical properties (conductivity, turbidity, etc.) of water are not shown. If the pressure is detected by the measuring device and then the controller 21 reduces the set pressure (PL) of the oil, the interface between the light liquid and the heavy liquid moves to the inner diameter side.
On the contrary, when the interface is too close to the inner diameter side, the function of the vertical separation plate 5 does not work sufficiently, and the water concentration in the oil increases. If the pressure PL of the oil is increased by the controller 21 by detecting the physical properties (capacitance, electric conductivity, turbidity, etc.) of R, R in Formula 3 increases and the interface moves to the outer diameter side. It will be. The physical property measuring device may be provided on both the heavy liquid side and the light liquid side as described above, but may be provided and operated only for those who place importance on the purity of the liquid to be recovered.

In this embodiment, the pressure controller is set manually, but the pressure controller can be cascade-controlled by the physical property measuring instrument. Further, although the opening degree of the opening of the outlet opening of the heavy liquid is adjusted by the dam 10, it is also possible to provide a control valve or the like in the pipeline connecting the outlet portion as a rotary joint. Further, if a flow meter is installed on the light liquid side or the heavy liquid side, it is effective for operation control.

[0014]

EFFECT OF THE INVENTION According to the present invention having the above-described structure and action, a mixed liquid of liquids having different specific gravities can be efficiently and highly accurately separated by the action of a separation plate and the action of centrifugal force capable of obtaining a large settling area. A separated liquid having stable properties can be obtained by a simple control means for adjusting the pressure on the light liquid or heavy liquid side.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

1; rotating body, 2; left shaft part, 3; right shaft part, 4; opening, 5;
Longitudinal separation plate, 6; separation plate shaft, 7; light liquid pipe, 8; dam plate,
9; rotary joint, 10; dam, 11; casing, 12; cover, 13; end plate, 14; rotary joint, 15; control valve, 16; stock solution inlet,
17; heavy liquid outlet, 18; light liquid outlet, 19; heavy liquid passage, 2
0; measuring instrument, 21; controller, 22; pulley, 23; heavy liquid chamber, 24; pipeline.

Claims (2)

[Claims] 1. A centrifugal separator for separating a mixed liquid of liquids having different specific gravities into a heavy liquid and a light liquid by utilizing centrifugal force, and horizontal rotations supported by left and right shafts (2, 3) respectively. A body (1), and a longitudinal separation plate (5) radially fixed to the peripheral surface of a separation plate shaft (6) mounted on the axial center of the rotary cylinder at a predetermined angle with the radial direction. A separating plate having a disk-shaped dam plate (8) coaxially mounted in the right shaft portion (3) of the rotary drum and integrally formed at the inner end, and an opening at the outer end. A light liquid pipe (7) fixed to the right end of the shaft, a means (10) for adjusting the opening of the heavy liquid outlet opening (4) at the right shaft end of the rotary drum, and an outlet opening of the light liquid pipe. And a rotary joint (9) for liquid-tightly sealing the light liquid outlet (18), and a rotary joint for liquid-tightly sealing the opening of the left shaft portion (2) of the rotary drum and the raw liquid inlet (16). Into (14) and a heavy liquid opening (4) and fluid-tightly surrounds the heavy liquid outlet of the right shaft part end (1
And a heavy liquid chamber (23) having 7). 2. A measuring device (20) mounted on a light liquid pipe line (24) for measuring pressure and an output signal of the measuring device,
The centrifugal separator for liquid-liquid separation according to claim 1, further comprising a controller (21) for controlling the pressure adjusting means (15).