Vertical centrifugal separation device

Abstract

Provided is a vertical centrifugal separation device that has a self-sealing function that is unaffected by the area of a supply hole and achieves excellent sealing. A vertical centrifugal separation device according to the present invention has a bowl, a casing that accommodates the bowl, and a self-sealing device that is provided between a supply hole and a bowl lower end opening and prevents separated liquid from draining out through the bowl lower end opening. The self-sealing device has a first seal body in which a bowl supply hole is formed, a second seal body to which a seal member is provided, and a mobile valve. The mobile valve can be operated between a lower position in which contact with the seal member prevents separated liquid that has flowed out of the supply hole from draining out through the bowl lower end opening and an upper position in which a liquid to be processed that flows from a supply nozzle toward the supply hole is allowed to pass. An urging member urges the mobile valve from the upper position toward the lower position.

Description

Vertical centrifuge

[0001] The present invention relates to a vertical centrifuge in which a bowl rotates around a vertical rotation axis.

[0002] Centrifuges are known that apply centrifugal force to the material to be processed supplied into the rotating bowl and perform separation operations according to the purpose, such as solid-liquid separation, liquid-liquid separation, or solid-liquid-liquid separation. Patent Document 1 discloses a centrifuge with a self-sealing function having an O-ring that expands and contracts (in other words, elastically deform) between a closed position that closes the supply hole through which the material to be processed passes toward the inside of the bowl and an open position that opens the supply hole.

[0003] This O-ring expands in diameter from the closed position to the open position by the centrifugal force during centrifugation, and contracts in diameter from the open position toward the closed position by the restoring force when centrifugation ends. By closing the supply hole with the O-ring, it is possible to prevent the separated liquid remaining in the bowl from being drained out. Since drainage is automatically prevented by the restoring force of the elastically deformed O-ring when centrifugation ends, it is called "self-sealing" (see Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2011-31152

[0005] The O-ring is originally a member for preventing liquid leakage and is not a member intended to be elastically deformed in the radial direction. Therefore, the elastic force decreases only by repeating expansion and contraction several times, and there may be a problem with sealing performance. In addition, since the elastic force, lifespan, etc. of the O-ring vary depending on the material, it was difficult to appropriately select the material.

[0006] Further, when increasing the area of the supply hole to increase the throughput, the size of the O-ring must be increased according to the area of the supply hole. Therefore, the rigidity of the O-ring increases, and it may be difficult to expand in diameter during centrifugation. Therefore, it was difficult to control the increase and decrease in the throughput of the liquid to be processed.

[0007] An object of the present invention is to provide a vertical centrifuge having an excellent sealing performance and a self-sealing function that is not affected by the area of the supply hole.

[0008] To solve the above problems, the vertical centrifugal separator of the present invention comprises (1) a bowl from which a liquid to be processed is supplied from a supply nozzle installed at the lower end opening of the bowl; a casing in which the bowl is housed so as to be rotatable around a vertical axis; and a self-sealing device installed between the supply hole and the lower end opening of the bowl to prevent the separated liquid from draining out from the lower end opening of the bowl, wherein the self-sealing device comprises a first seal body that closes the lower end opening of the bowl body and has the supply hole formed therein, a cylindrical second seal body provided with a ring-shaped sealing member, and a movable valve, wherein the movable valve is operable between a lower position that prevents drain-out by being in close contact with the seal member and an upper position that allows the liquid to be processed to pass from the supply nozzle toward the supply hole, and the movable valve has a biasing member that biases the movable valve from the upper position toward the lower position.

[0009] (2) The vertical centrifugal separator according to (1) above, characterized in that the movable valve comprises a valve body and a biasing member housing portion that protrudes cylindrically from the upper surface of the valve body, and the biasing member is housed in the biasing member housing portion.

[0010] (3) The vertical centrifugal separator according to (1) or (2) above, characterized in that the biasing member is a coil spring.

[0011] (4) The vertical centrifugal separator according to (1) or (2) above, characterized in that a valve body tapered surface is formed on the side surface of the valve body that is in close contact with the sealing member at the lower position, and the valve body tapered surface has a tapered shape that decreases in diameter as it goes downward.

[0012] (5) The vertical centrifugal separator according to (3) above, characterized in that a valve body tapered surface is formed on the side surface of the valve body that is in close contact with the sealing member at the lower position, and the valve body tapered surface has a tapered shape that decreases in diameter as it goes downward.

[0013] (6) The vertical centrifugal separator according to (1) or (2) above, characterized in that the first seal body has a two-stage structure comprising a first seal body large diameter portion and a first seal body small diameter portion formed on the upper surface of the first seal body large diameter portion, and the first seal body large diameter portion has a screw portion formed thereon for fixing the first seal body to the bowl.

[0014] (7) The vertical centrifugal separator according to (3) above, characterized in that the first seal body has a two-stage structure comprising a first seal body large diameter portion and a first seal body small diameter portion formed on the upper surface of the first seal body large diameter portion, and the first seal body large diameter portion has a screw portion formed thereon for fixing the first seal body to the bowl.

[0015] (8) The vertical centrifugal separator according to (7), characterized in that a projection is formed on the inner top surface of the small diameter portion of the first seal body, which is inserted into the spiral of the coil spring, and the coil spring is sandwiched between the inner top surface of the first seal body and the biasing member housing portion.

[0016] (9) The vertical centrifugal separator according to (6) above, characterized in that a through hole is formed on the side surface of the small diameter portion of the first seal body.

[0017] (10) The vertical centrifugal separator according to (1) or (2) above, characterized in that the second seal body has a second seal body tapered surface which decreases in diameter as it goes downward, and a sealing groove for housing the sealing member is formed around the second seal body tapered surface.

[0018] According to the present invention, it is possible to provide a vertical centrifugal separator that has excellent airtightness and a self-sealing function that is not affected by the area of ​​the supply port.

[0019] This is a longitudinal cross-sectional view of a vertical centrifugal separator. This is a front view of a vertical centrifugal separator. This is a perspective view of the first seal body. This is a perspective view of the movable valve. This is a perspective view of the second seal body. This is a perspective view of the dispersion member. This is a perspective view of the support ring. This is a cross-sectional view of a part of the vertical centrifugal separator (near the self-sealing device). This is a diagram showing the self-sealing device in the state where it has moved from the lower position in Figure 4 to the upper position. This is a diagram showing the self-sealing device in the state where it has returned from the upper position in Figure 5 to the lower position. This is a diagram corresponding to Figure 4 of Modification 1. This is a diagram corresponding to Figure 4 of Modification 2.

[0020] Figure 1 is a longitudinal cross-sectional view of the vertical centrifugal separator of this embodiment. Figure 2 is a front view of the vertical centrifugal separator of Figure 1. Figures 3A to 3E are exploded perspective views of the components constituting the self-sealing device, with Figure 3A being a perspective view of the first seal body, Figure 3B being a perspective view of the movable valve, Figure 3C being a perspective view of the second seal body, Figure 3D being a perspective view of the dispersion member, and Figure 3E being a perspective view of the support ring. Figure 4 is a cross-sectional view of a part of the vertical centrifugal separator (near the self-sealing device).

[0021] Referring to these figures, the vertical centrifugal separator 1 comprises a bowl (cylindrical rotating cylinder) 2 from which the liquid to be processed is supplied from a supply nozzle 24 installed at the lower end opening 22a of the bowl (see Figure 4), a casing 3 in which the bowl 2 is housed so as to be rotatable around a vertical axis, and a self-sealing device 6 installed between the supply hole 612a and the lower end opening 22a of the bowl to prevent the separated liquid from draining out from the lower end opening 22a of the bowl.

[0022] The casing 3 comprises a casing body 31 supported by a support device 5, and an upper casing 32 detachably attached to the upper part of the casing body 31. A temperature control device 33 for temperature control during centrifugal separation may be installed on the inner wall of the casing body 31. Figure 1 illustrates a cooling coil as the temperature control device 33, but a heating coil may also be used. The temperature control device 33 may also be omitted. In Figure 1, the casing 3 is formed in a shape where the inner diameter expands towards the top, but the shape of the casing 3 is not limited to this.

[0023] The upper casing 32 functions as a liquid receiving section that receives the separated liquid discharged from the upper side of the bowl 2 by centrifugal force and then guides it to the recovery nozzle 34. Therefore, the gap between the upper casing 32 and the rotation axis of the bowl 2 is sealed by a sealing member (not shown). A recovery pipe (not shown) is detachably connected to the recovery nozzle 34, and this recovery pipe is connected to a storage tank for the separated liquid. In addition, when removing the bowl 2 from the casing 3 or performing maintenance work on the device, the upper casing 32 is removed from the casing body 31, and the upper opening of the casing body 31 is opened.

[0024] Bowl 2 has a cylindrical bowl body 21 with a hollow interior and a liquid receiving section 22 attached to the lower end of the bowl body 21. A lower end opening 21a is formed on the bottom surface of the bowl body 21, and the first seal body 61 of the self-sealing device 6 is attached in a position that closes this lower end opening 21a. A lower end opening 22a is formed in the liquid receiving section 22 for supplying the liquid to be treated. A liquid supply nozzle 24 is inserted into the lower end opening 22a at a position retracted from the inner wall surface of bowl 2. The self-sealing device 6 is provided on the upper end side of the lower end opening 22a.

[0025] The dimensions of bowl 2 may be an inner diameter of 95 to 160 mm and a length of 457 to 720 mm. The material of bowl 2 may be stainless steel. However, the dimensions and material of bowl 2 are not limited to these.

[0026] The bowl 2 is detachably connected to the rotating shaft 26a of the bearing assembly 26 by a coupling nut 25, which is a means of attachment and detachment. The bearing assembly 26 is connected to the rotating pulley 42 of the drive motor 4 via a rotating belt 41. Therefore, a threaded portion is formed at the upper end of the rotating shaft of the bowl 2, which engages with the coupling nut 25. The bowl 2 rotates around the vertical axis in a suspended state by being connected to the bearing assembly 26. On the other hand, when removing the bowl 2 from the casing 3, the connection between the bowl 2 and the bearing assembly 26 is released by releasing the connection by the coupling nut 25.

[0027] Next, the configuration of the self-sealing device 6 will be described in detail with reference to Figures 3A to 3E and Figure 4. The vertical centrifugal separator 1 of this embodiment employs a batch system in which the separated liquid is continuously discharged during centrifugal separation, and the solid material is discharged by removing the bowl 2 from the casing 3.

[0028] The first seal body 61 has a two-stage structure consisting of a large-diameter portion 61a and a small-diameter portion 61b formed on the upper surface of the large-diameter portion 61a, and is formed in a cylindrical shape with a closed upper end and an open lower end. A threaded portion 611a is formed on the outer circumferential surface of the large-diameter portion 61a of the first seal body, and by fastening this threaded portion 611a to the threaded portion 211a of the bowl 2, the first seal body 61 can be mounted in a position that closes the lower end opening 21a of the body.

[0029] A supply hole 612a is formed above the threaded portion 611a, penetrating the side wall of the large-diameter portion 61a of the first seal body. Since the lower end opening 21a of the bowl body portion 21 is closed by the first seal body 61, the liquid to be treated sprayed from the supply nozzle 24 flows into the interior of the bowl body portion 21 through the supply hole 612a. It is desirable to form multiple supply holes 612a in the circumferential direction of the first seal body 61. It is desirable that the supply holes 612a be spaced approximately equally.

[0030] The small-diameter portion 61b of the first seal body protrudes from the upper surface of the large-diameter portion 61a of the first seal body, and a punch hole 611b is formed on the outer circumferential surface of the small-diameter portion 61b of the first seal body. The "punch hole 611b" corresponds to the "through hole" described in claim 9. A projection 612b extending downward is formed on the inner top surface of the small-diameter portion 61b of the first seal body.

[0031] The movable valve 62 consists of a valve body 62a, a biasing member housing 62b, and a biasing member 62c. The side surface of the valve body 62a has a valve body tapered surface 62a1 that decreases in diameter towards the bottom. The biasing member housing 62b has a bottomed cylindrical housing opening 62b1, and the biasing member 62c is housed in this housing opening 62b1. The biasing member 62c may be a coil spring.

[0032] Here, the biasing member 62c is housed in the housing opening 62b1 in a state shorter than its natural length, and the movable valve 62 is biased downward by the elastic force charged in the biasing member 62c.

[0033] A projection 612b is inserted into the spiral of the biasing member 62c. In other words, the biasing member housing 62b is located on the outside of the biasing member 62c, and the projection 612b is located on the inside of the biasing member 62c. Therefore, the cooperation of the biasing member housing 62b and the projection 612b prevents the biasing member 62c from collapsing when it expands or contracts. It is desirable that the tip of the projection 612b extends into the housing opening 62b1 of the biasing member housing 62b.

[0034] The outer diameter of the biasing member housing portion 62b is set to be slightly smaller than the inner diameter of the small diameter portion 61b of the first seal body, and the inner diameter of the biasing member housing portion 62b is set to be larger than the outer diameter of the projection portion 612b.

[0035] The second seal body 63 is formed in a cylindrical shape, and an enlarged diameter support portion 63a is formed at its lower end, on which the first seal body 61 (first seal body large diameter portion 61a) is supported. The inner circumferential surface of the second seal body 63 has a second seal body tapered surface 63b that decreases in diameter towards the bottom, and a sealing groove portion 63c extending in the circumferential direction is formed on this second seal body tapered surface 63b, into which a seal member 63d is fitted. The second seal body tapered surface 63b and the valve body tapered surface 62a1 have approximately equal taper angles.

[0036] The sealing member 63d may be an O-ring. The O-ring may be an elastic material such as rubber. The tapered surface 62a1 of the valve body is in close contact with the sealing member 63d, which prevents the remaining separated liquid from being drained out.

[0037] In Patent Document 1, however, the O-ring needs to be elastically deformed in the diameter expansion direction, making material selection difficult. In this embodiment, the sealing member 63d only needs to perform its sealing function when it is in close contact with the tapered surface 62a1 of the valve body, making material selection relatively easy.

[0038] A dispersion member holding groove 63e, which widens radially outward, is formed around the lower end of the inner circumferential surface of the second seal body 63 (see Figure 4). The dispersion member 64 is formed in a roughly cross shape in plan view, and a dispersion member leg portion 64a is formed at the lower end of the dispersion member 64, protruding toward the dispersion member holding groove 63e. By engaging the dispersion member leg portion 64a with the dispersion member holding groove 63e, the dispersion member 64 can be positioned below the movable valve 62.

[0039] The support ring 65 is supported by the bowl 2 on its lower surface and supports the second seal body 63 on its upper surface.

[0040] Next, the operation of the self-sealing device 6 will be described while referring to FIGS. 4 to 6. FIG. 5 shows a state where the self-sealing device operates from the lower position to the upper position in FIG. 4. FIG. 6 shows a state where the self-sealing device returns from the upper position to the lower position in FIG. 5. The symbol L in FIG. 5 indicates the separation liquid or the liquid to be treated. The symbol L in FIG. 6 indicates the separation liquid.

[0041] In the state shown in FIG. 4, while rotating the bowl 2 about the vertical axis, the supply nozzle 24 is operated to spray the liquid to be treated. The sprayed liquid to be treated is divided by the dispersion member 64, and then climbs the second seal body tapered surface 63b by centrifugal force, pushing up the movable valve 62. That is, the movable valve 62 automatically rises by the liquid pressure of the liquid to be treated during centrifugation.

[0042] When the movable valve 62 is pushed up, a passage for allowing the liquid to be treated to pass between the movable valve 62 and the second seal body 63 is formed so that the valve body tapered surface 62a1, which had been in close contact with the seal member 63d until then, is separated therefrom, and the liquid to be treated flows into the inside of the bowl body 21 (bowl 2) through the supply hole 612a from this passage. The arrow in FIG. 5 indicates the inflow path of the liquid to be treated flowing into the bowl body 21.

[0043] The movable valve 62 cannot rise when the valve body 62a abuts against the large-diameter portion 61a of the first seal body and stops at that position (corresponding to the upper position). The upper position can be alternatively referred to as the liquid passage position for the liquid to be treated.

[0044] When the liquid to be treated flows into the bowl body 21, the liquid to be treated is solid-liquid separated into solid matter and separation liquid by the action of centrifugal force. The centrifugally separated separation liquid is continuously recovered by the recovery nozzle 34, and the centrifugally separated solid matter is gradually accumulated on the lower side of the bowl 2.

[0045] When the rotation time of bowl 2 reaches a predetermined time, or when the amount of accumulated solids reaches a predetermined amount, the rotation of bowl 2 is stopped, and the supply of the liquid to be processed is also stopped. When the supply of the liquid to be processed is stopped, the external force that would raise the movable valve 62 is removed, and the movable valve 62 immediately descends due to the biasing force charged in the biasing member 62c. When the movable valve 62 descends, the tapered surface 62a1 of the valve body comes into close contact with the sealing member 63d, thus preventing the drain-out of the separated liquid remaining inside bowl 2. Figure 6 shows the state after the movable valve 62 has returned to its lower position. The lower position can also be called the drain-out prevention position.

[0046] Thus, in this embodiment, the movable valve 62 is pushed up from the lower position to the upper position by the hydraulic pressure of the liquid being processed, which is acted upon by centrifugal force. Furthermore, when the supply of the liquid being processed is stopped, the movable valve 62 returns to the lower position due to the biasing force charged in the biasing member 62c, thereby automatically preventing drain-out. Conventionally, when the bowl 2 was stopped, the separated liquid would drain out (fall), and the lower bearing of the bowl (hereinafter referred to as the drag bushing) would be submerged in water. Since there are foreign substances such as grease and wear particles around the drag bushing, the separated liquid containing these foreign substances could flow from the bottom of the bowl into the bowl (so-called contamination). In contrast, in the present invention, when the supply of the liquid being processed is stopped, the self-sealing function immediately works, automatically preventing drain-out, thus effectively preventing the occurrence of contamination. By preventing the occurrence of contamination, the effort required for cleaning and other tasks can also be reduced.

[0047] Furthermore, even if the first seal body 61 is enlarged to increase the area of ​​the supply hole 612a, there is no need to change the lifting mechanism of the movable valve 62. Therefore, a vertical centrifugal separator with a self-sealing function that is not affected by the area of ​​the supply hole can be provided.

[0048] Furthermore, compared with the conventional self-sealing device that expands and contracts the O-ring in the radial direction, the self-sealing device 6 can enhance the sealing property of the separation liquid. That is, a winding spring or the like used for the biasing member 62c has a longer life against repeated stress than the O-ring of Patent Document 1, so the sealing property of the separation liquid can be enhanced. Since the biasing member 62c does not immediately lose its elastic force like an O-ring, the long life and stability of the self-sealing function can be enhanced.

[0049] The separated liquid with drainage prevented can be drained by removing the supply nozzle 24 and pushing up the movable valve 62 with a rod or the like from below the bowl 2. Therefore, if a collection container is prepared in advance below the bowl 2 before pushing up the movable valve 62, the separated liquid can be easily collected.

[0050] (Modification Example 1) In the above-described embodiment, the biasing member 62c is a winding spring, but the present invention is not limited to this, and a biasing member different from the winding spring may be used. FIG. 7 is a drawing corresponding to FIG. 4 showing Modification Example 1 of the biasing member, and elements having the same functions as those in the above-described embodiment are denoted by the same reference numerals. In the movable valve 62 of this modification example, a rubber pressing portion 62d is formed on the upper surface of the valve body 62a instead of the biasing member accommodating portion 62b. A biasing member 62c made of elastic rubber is sandwiched between the tip of the rubber pressing portion 62d and the inner top surface of the first seal body small diameter portion 61b. As shown in FIG. 7, in the lower position (drainage prevention position), the elastically deformed biasing member 62c biases the movable valve 62 downward, and the valve body tapered surface 62a1 is in close contact with the seal member 63d. When the liquid to be processed is supplied, the movable valve 62 rises while resisting the elastic force of the biasing member 62c (elastic rubber). When the supply of the liquid to be processed is stopped, the movable valve 62 descends due to the elastic force charged in the biasing member 62c.

[0051] (Modification 2) In the above embodiment, the surface on which the movable valve 62 and the second seal body 63 are in close contact is a tapered surface, but the present invention is not limited to this, and a surface other than a tapered surface may be used. Figure 8 is a drawing corresponding to Figure 4 of this modification. A sealing groove 63c extending in the circumferential direction is formed on the upper surface of the second seal body 63, and a sealing member 63d is fitted into this sealing groove 63c. As shown in Figure 8, in the lower position (drain-out prevention position), the lower surface of the valve body 62a is in close contact with the sealing member 63d.

[0052] 1 Vertical centrifugal separator 2 Bowl 3 Casing 6 Self-sealing device 21 Bowl body 21a Lower end opening of body 22 Liquid receiving section 22a Lower end opening of bowl 24 Supply nozzle 61 First seal body 61a Large diameter section of first seal body 61b Small diameter section of first seal body 611a Threaded section 611b Hole 612a Supply hole 612b Projection 62 Movable valve 62a Valve body 62b Biasing member housing section 62b1 Housing opening 62c Biasing member 62a1 Tapered surface of valve body 63 Second seal body 63a Enlarged diameter support section 63b Tapered surface of second seal body 63c Sealing groove section 63d Seal member

Claims

1. A vertical centrifugal separator comprising: a bowl from which a liquid to be processed is supplied from a supply nozzle installed at the lower end opening of the bowl; a casing in which the bowl is housed so as to be rotatable around a vertical axis; and a self-sealing device installed between the supply hole and the lower end opening of the bowl to prevent the separated liquid from draining out from the lower end opening of the bowl, wherein the self-sealing device comprises: a first seal body that closes the lower end opening of the bowl body and has the supply hole formed therein; a cylindrical second seal body provided with a ring-shaped sealing member; and a movable valve, wherein the movable valve is operable between a lower position that is in close contact with the sealing member to prevent draining out and an upper position that allows the liquid to be processed to pass from the supply nozzle toward the supply hole; and the movable valve has a biasing member that biases the movable valve from the upper position toward the lower position.

2. The vertical centrifugal separator according to claim 1, characterized in that the movable valve comprises a valve body and a biasing member housing portion that protrudes cylindrically from the upper surface of the valve body, and the biasing member is housed in the biasing member housing portion.

3. The vertical centrifugal separator according to claim 1 or 2, characterized in that the biasing member is a coil spring.

4. The vertical centrifugal separator according to claim 1 or 2, characterized in that a valve body tapered surface is formed on the side surface of the valve body that is in close contact with the sealing member at the lower position, and the valve body tapered surface has a tapered shape that decreases in diameter as it goes downward.

5. The vertical centrifugal separator according to claim 3, characterized in that a valve body tapered surface is formed on the side surface of the valve body that is in close contact with the sealing member at the lower position, and the valve body tapered surface has a tapered shape that decreases in diameter as it goes downward.

6. The vertical centrifugal separator according to claim 1 or 2, characterized in that the first seal body has a two-stage structure comprising a large-diameter portion of the first seal body and a small-diameter portion of the first seal body formed on the upper surface of the large-diameter portion of the first seal body, and the large-diameter portion of the first seal body has a screw portion formed thereon for fixing the first seal body to the bowl.

7. The vertical centrifugal separator according to claim 3, characterized in that the first seal body has a two-stage structure consisting of a large-diameter portion of the first seal body and a small-diameter portion of the first seal body formed on the upper surface of the large-diameter portion of the first seal body, and a screw portion for fixing the first seal body to the bowl is formed in the large-diameter portion of the first seal body.

8. The vertical centrifugal separator according to claim 7, characterized in that a projection is formed on the inner top surface of the small-diameter portion of the first seal body, which is inserted into the spiral of the coil spring, and the coil spring is sandwiched between the inner top surface of the first seal body and the biasing member housing portion.

9. The vertical centrifugal separator according to claim 6, characterized in that a through hole is formed on the side surface of the small-diameter portion of the first seal body.

10. The vertical centrifugal separator according to claim 1 or 2, characterized in that the second seal body has a second seal body tapered surface that decreases in diameter as it extends downward, and a sealing groove for housing the sealing member is formed circumferentially on the second seal body tapered surface.

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