KR20130136159A

KR20130136159A - Rotational coalescing plate particle separator

Info

Publication number: KR20130136159A
Application number: KR1020120059766A
Authority: KR
Inventors: 조기환
Original assignee: 조기환
Priority date: 2012-06-04
Filing date: 2012-06-04
Publication date: 2013-12-12

Abstract

The present invention minimizes the passage path of particles in the same rotor inner space by arranging the variable rotating plate and the fixed rotating plate at equal intervals about the rotation axis in the rotor of the centrifuge, so that the particles are kept within a predetermined residence time determined by the rotor volume and flow rate. Attached to the rotating plate to effectively separate from the fluid, the separation area of the particle corresponds to the total area of the rotational direction of the built-in rotating plate is superior particle separation efficiency than the conventional continuous centrifuge.

Description

Rotational Coalescing Plate Particle Separator

The present invention relates to a rotary plate solid coalescing separator that effectively separates particles from a fluid. More specifically, the variable rotary plate and the fixed rotary plate are disposed in the rotor of the centrifuge at equal intervals about the rotational axis so that the particles can be spaced in the same rotor internal space. By minimizing the passage path, the particles adhere to the rotating plate within a certain residence time determined by the rotor volume and flow rate, so that the particles can be effectively separated from the fluid, and the separation area of the particles corresponds to the total area in the rotational direction of the rotating plate. Therefore, the present invention relates to a rotating plate solids separator having superior particle separation efficiency than conventional continuous centrifuges.

There are techniques that use gravity or centrifugal force to separate particles from a fluid. To separate flotation particles, the concentration and density of the particles must be taken into account. Particles in a fluid are settled by gravity in a fluid having a lower specific gravity than the particles, and show different settling speeds depending on the diameter and density of the particles. Therefore, in order to effectively separate small particles in the fluid, it is necessary to increase the separation area or coalesce small particles to increase the settling speed. In the case of small particles, the separation efficiency can be improved by adding centrifugal force when settling by gravity.

As a device using centrifugal force, industrial products such as a tubular centrifuge, a decanter centrifuge, and a disc centrifuge can be used, and the size of the separated particles of these products depends on the degree of application of the centrifugal acceleration due to the rotational force of the centrifuge. Are distinguished. Tubular centrifuges are capable of increasing rotational power from 15,000 to 20,000 rpm and are used to separate small amounts of particles down to 0.1 microns. Decanter centrifuges can process a large amount of fluid with a rotational force of 3,000 to 4,000 rpm, and polymer coagulants are added to the fluid to improve separation efficiency. Disc centrifuges vertically stack 40-100 sheets of conical disc plates at intervals of 1 to 3 mm to widen the separation area and allow fluid to pass between the disc plates, allowing small particles to coalesce at the bottom of the disc plate. The particles can also be separated in large quantities. Disc centrifuges are widely used in the dairy, pharmaceutical, and food and beverage industries because of their low classification limits and the ability to process large amounts of fluids.However, the disc gaps between the disc plates are narrow and contain viscous samples or coarse particles. Blockage between the disks reduces throughput and makes post-management difficult.

The settling velocity of solids or particles in the gravitational field is directly affected by the particle size, specific gravity difference and the viscosity of the suspended solids. Under centrifugal force, the settling velocity of solids or particles is determined by the nature of the suspension, the flow rate of the fluid and the centrifuge size, the residence time and the settling path. The sedimentation rate Vc of the particles in the centrifugal field and the particle sedimentation rate Vg in the gravitational field apply the following formulas, respectively.

* Note: ρS: specific gravity of particles

ρL: specific gravity of the fluid

μ: viscosity of the fluid

d: diameter of particle

r: distance from the rotating shaft

ω: Angular velocity

g: acceleration of gravity

The proper separation efficiency of the centrifuge in the centrifugal field is not determined solely by the flow rate. The residence time of the fluid containing particles in the centrifuge space (the volume of the rotor) can compensate for small centrifugal acceleration. Short particle passages through which particles can be collected also allow for increased flow rates with moderate separation efficiency.

As shown in FIG. 12, if the diameter of the centrifuge rotor is r2, any point of particles to be separated is rs, the surface of the fluid is r1, and the time required for particles to separate is T, the following formula can be applied. .

Small particle separation rates give a long residence time for the particles to reach the rotor wall, or short particle passage distances or high angular velocities. Industrial centrifuges that require continuous operation are subject to constraints to meet the above conditions due to instrument configuration and fluid characteristics.

Accordingly, an object of the present invention is to place the variable rotating plate and the fixed rotating plate at equal intervals about the rotation axis inside the rotor of the centrifuge to minimize the passage path of the particles in the same rotor internal space, which is determined according to the rotor volume and flow rate Particles adhere to the rotating plate within the residence time to effectively separate the particles from the fluid, and the separation area of the particles corresponds to the total area in the direction of rotation of the built-in rotating plate. It is to provide a solid coalescence separator.

In addition, another object of the present invention is to separate the variable rotating plate and the fixed rotating plate up and down to separate the solids deposited first, and then randomly rotate the variable rotating plate to shake off the deposited solids, the solids deposited on the fixed rotating plate The solid separation plate is attached to the top of the variable rotating plate to scrape out the solids, thereby providing a solid coalescing separator capable of stably separating the solids from the fluid even though the solids and fluids have various characteristics.

It is still another object of the present invention to increase the separation efficiency of a fluid containing solids determined according to the rotor volume and the flow rate of the centrifuge, to reduce the throughput due to clogging of the inside of the rotor by viscous fluid or coarse particles, and It is to provide a solid coalescing separator for easy maintenance.

Solid material separator according to the present invention for achieving the above object by arranging the variable rotary plate and the fixed rotary plate at equal intervals about the rotation axis in the rotor of the centrifuge to minimize the passage path of particles in the same rotor inner space, The particles adhered to the rotor plate within a certain residence time determined by the rotor volume and flow rate to effectively separate them from the fluid.The particle separation area corresponds to the total area in the direction of rotation of the embedded rotor plate. The separation efficiency is excellent.

In addition, when treating a fluid containing high viscosity or coarse particles in the conventional disc centrifuge, the fluid passage path between the disk plates is frequently blocked, so that it is difficult to manage post-mortem, but the present invention provides a variable rotating plate and a fixed rotating plate. After separating the solids deposited by separating them up and down the first time, the variable rotating plate can be randomly rotated to shake off the deposited solids.The solids deposited on the fixed rotating plate can be attached to the top of the variable rotating plate to scrape off the solids. It is possible to stably separate the solids from the fluid even if the properties of the solids and fluids vary.

As a result, the solid coalesced separator according to the present invention improves the separation efficiency because the solid particles contained in the fluid pass between the rotating plates disposed inside the rotor and coalesce at the rotating plate side in the rotational direction within the residence time. Solids deposited during the separation of the rotating plate can be effectively dropped, so that the solids can be separated and dehydrated effectively.

1 is a particle copolymer separator process diagram
Figure 2 is an illustration of the variable rotating plate rotor and fixed rotating plate rotor combined rotation (particle separation)
Figure 3 is an illustration of the fixed rotor rotor position conversion (solids removal)
Figure 4 is a cross-sectional view of the variable rotating plate, fixed rotating plate
5 is a cross-sectional view of the variable planar, fixed plane rotary plate cross section
6 is a perspective view of the variable rotor plate rotor
7 is a perspective view of the fixed rotor rotor
8 is a cross-sectional view of the variable variable rotor plate rotor coupled;
9 is a variable rotation plate free rotation position
10 is an illustration of fluid inflow
11 is an exemplary view of a fluid discharge device
12 is a conceptual diagram of particle separation
13 is a perspective view showing an example in which the slide shaft of the variable rotor plate is coupled to the spline hollow shaft of the variable rotor plate;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, in the RPS particle coalescing separation process according to the present invention, after a fluid including solids such as fluid, sewage, and industrial wastewater in an industrial process flows into a 'rotating plate solid coalescing separator', a fixed rotating plate and a variable rotating plate are provided. Due to the centrifugal force formed by the high-speed rotation of the rotor installed therein and the specific gravity difference between the fluid and the solid or unmixed fluid, the solid or fluid having a high specific gravity is deposited on the rotor wall and the surface of the rotating side of the rotating plate and has a small specific gravity or fluid. Are floated toward the rotating shaft and separated and discharged through the outlets arranged according to the specific gravity difference.

2, 3, and 13, the solid coalesced separator according to the present invention, the rotor 3 is disposed inside the cylindrical housing 1, the rotor 3 and the variable rotary plate rotor (3-1) It consists of a fixed rotary plate rotor (3-2), the fixed rotary plate rotor (3-2) is mounted to the position shifting lifter (7) mounted on the upper end of the cylindrical housing (1), of the fixed rotary plate rotor (3-2) The sliding shaft 14 is fitted to the spline hollow shaft 15 (see FIG. 6) of the variable rotor plate 3-1, and the fixed rotor plate rotor 3-2 is fixed by the position change lifter 7 to the variable rotor plate rotor ( 3-1) can be elevated relative to the sliding shaft 14, the sliding shaft 14 can be moved up and down relative to the spline hollow shaft 15, the sliding shaft 15 is lowered, the sliding shaft ( When 14 is inserted into the spline hollow shaft 15, the fixed rotating plate (3-21) of the fixed rotating plate rotor (3-2) is a variable rotating plate rotor ( The fixed rotor plate 3-2 is disposed between the variable rotor plates 3-11 of 3-1 and the sliding shaft 14 is lifted up and the sliding shaft 14 is drawn out to the spline hollow shaft 15. The fixed rotating plate (3-21) of the variable rotating plate rotor (3-1) is separated from the variable rotating plate (3-11), the variable rotating plate rotor (3-1) is mounted on the lower end of the cylindrical housing (1) 5), the rotational power of the spindle (5) is transmitted to the variable rotor plate rotor (3-1) and the fixed rotor plate rotor (3-2), the hollow is formed on the rotary shaft (6) of the spindle (5), When the fluid is supplied to the rotor 3 through the hollow part of the rotating shaft 6, the fluid is separated into sludge, heavy fluid and light oil by the rotation of the rotor 3, so that the sludge is fixed rotor plate (3- of the rotor 3). 21) and the heavy fluid discharge pipe (12) and the light oil discharge pipe (13) through the fluid discharge device (2) attached to the variable rotating plate (3-11), and the heavy fluid and the light oil are mounted on the top of the rotor (3), respectively. With each .

2 and 10, the spindle 5 is composed of a spindle housing 5-1 fixed to the cylindrical housing 1 and a rotating shaft 6 rotatably fitted to the spindle housing 5-1. do.

The spindle housing 5-1 has a lower flange 11 at the bottom thereof, which is fixed to the bottom of the cylindrical housing 1 by bolts.

The rotary shaft 6 has a hollow portion 6-1, and the upper flange is fitted to the rotor wheel 3-13, the upper flange plate 6-2 is the lower surface of the rotor wheel (3-13) Is coupled to.

10 and 13, the rotor wheel 3-13 has a hole 3-15 through which the upper end of the rotation shaft 6 can be fitted, and is radially around the hole 3-15. A plurality of fluid dispersion grooves 3-14 curved to each other are formed, and a lower end of the spline shaft 15 is disposed on the upper portion of the fluid dispersion grooves 3-14.

Thereby, when fluid is supplied to the hollow part 6-1 of the rotating shaft 6, the fluid will open the fluid dispersion groove 3-14 formed in the rotor wheel 3-13 at the hollow part 6-1. Is supplied to the rotor (3).

The rotor 3 shown in FIG. 2 is composed of a variable rotor plate rotor 3-1 and a fixed rotor plate rotor 3-2. The variable rotating plate rotor 3-1 is formed in a curved or planar shape in which the variable rotating plate 3-11 is curved, as shown in FIGS. 4 and 5, and as shown in FIGS. 6 and 13, the variable rotating plate ( The cylindrical shaft 3-16 is attached to the inner end of 3-11, and the rotary shaft 3-16 is fitted into the vertical groove 3-17 of the variable rotating plate fixing member 3-12. A clearance is formed between the variable rotary plate 3-11 and the vertical groove 3-17, and the variable rotary plate 3-11 can angularly move around the rotary shaft 3-16 by the clearance. The spline hollow shaft 15 is fitted to the hollow portion of the variable rotating plate fixing member 3-12, and the flange portion 15-2 formed at the lower end of the spline hollow shaft 15 is rotated by a bolt (not shown). Coupled to the wheel 3-13, the rotational force of the spindle 5 is transmitted to the spline hollow shaft 15 and the variable rotating plate fixing member 3-12.

4 and 5, the fixed rotor plate 3-2 is formed in a curved or planar shape in which the fixed rotor plate 3-21 is curved, and an outer end of the fixed rotor plate 3-21 is fixed rotor plate. It is fixed at equal intervals on the inner circumferential surface of the housing 3-22, and as shown in FIG. 7, the fluid discharge device 2 is mounted on the upper end of the fixed rotating plate housing 3-22, and as shown in FIG. The bearing member 14-5 is mounted below the upper end of the fixed rotor plate housing 3-22, and the upper end of the sliding shaft 14 is fitted to the bearing member 14-5 to be supported. A bushing 14-6 is mounted on the upper end of 3-22 to support the fixed rotor plate rotor through the fluid discharge device 2, and the movable plate 9 of the position change lifter 7 is attached to the bushing 14-6. -2) is mounted.

In addition, the fixed rotating plate rotor (3-2) is a sliding shaft 14 is fitted to the spline hollow shaft 15 of the variable rotating plate rotor (3-1), the rotational force of the spline hollow shaft 15 is the sliding shaft 14 The fixed rotor plate rotor 3-2 can rotate at the same speed as the variable rotor plate rotor 3-1. The lower end end of the fixed rotor plate housing is closed with an O-ring, and is in close contact with the outer side of the rotor wheel 3-13 constituting the variable rotor plate rotor 3-1, so that the variable rotor plate 3-1 and the fixed rotor plate rotor ( Fluid does not leak when 3-2) is bound and rotates

Referring again to FIGS. 2 and 3, the position change lifter 7 is equipped with an upper flange 10 at the top of the cylindrical housing 1 and driven by a motor (not shown) to the upper flange 10. The screw shaft 9 and the guide shaft 8 are mounted, the nut 9-1 is fastened to the screw shaft 9, and the nut 9-1 is mounted to the movable plate 9-2.

Thus, as shown in FIG. 3 in the state of FIG. 2, when the nut 9-1 is raised upward by the rotation of the screw shaft 9, the movable plate 9-2 moves the guide shaft 8. As a result, the movable plate 9-2 is connected to the fixed rotor plate rotor 3-2 through the bushing 14-6, and the fixed rotor plate rotor 3- is lifted by the movable plate 9-2. 2), the sliding shaft 14 of the fixed rotor plate 3-2 is lifted up, and is drawn out to the spline hollow shaft 15, and the fixed rotor plate 3-21 of the fixed rotor plate 3-2 is lifted. As it is raised, it is separated from the variable rotating plate 3-11 of the variable rotating plate rotor 3-1.

In the variable rotating plate rotor 3-1 and the fixed rotating plate rotor 3-2, as shown in FIGS. 4 and 5, the same number of variable rotating plate 3-11 and fixed rotating plate 3-21 are respectively provided. Is mounted. The number of rotating plates can be loaded from 30 to 60, depending on the nature of the fluid or solid particles and the size of the device. When the variable rotating plate rotor 3-1 and the fixed rotating plate rotor 3-2 are bound together, as shown in Fig. 8, the interval between the variable rotating plate 3-11 and the fixed rotating plate 3-21 becomes narrow or It can be widened, the interval between the variable rotating plate (3-11) and the fixed rotating plate (3-21) is maintained at a constant rotation speed (3,000 ~ 4,000rpm).

The rotary plate solid coalescing separator according to the present invention configured as described above operates as follows.

When the fluid is supplied to the end portion 6-1 of the rotating shaft 6 of the spindle 5 which rotates at high speed, the fixed rotating plate 3 is disposed in the hollow portion 6-1 via the fluid dispersion groove 3-14. -21) and into the gap (6-15 mm) between the variable rotor plate 3-11. As the rotor 3 is rotated at a high speed by the rotation shaft 6, the solid particles contained in the fluid are attached to the rotational surfaces of the variable rotating plate 3-11 and the fixed rotating plate 3-21 to remove from the fluid. The separated solids are moved to the inner surface of the fixed rotating plate housing (3-22) of the fixed rotating plate rotor (3-2) and the outer surface of the variable rotating plate (3-11) and the fixed rotating plate (3-21) according to the centrifugal force. As it settles, the separated fluid moves to the axis of rotation and floats. The separated fluids are concentrically axially along the specific gravity in a strong centrifugal force field and layered into heavy fluids such as water and light fluids such as oil, respectively, and supplied to the fluid discharge device 2, where the heavy fluid is fluid The heavy fluid discharge pipe 12 disposed at the lower end of the collecting tank 2-5 is discharged, and the light oil is separated and discharged into the diesel fuel discharge pipe 13 disposed at the upper end of the fluid collecting container 2-5.

When a certain time has elapsed and the gap between the fixed rotating plate 3 -21 and the variable rotating plate 3-11 is filled with solids, the supply of fluid is interrupted, and the rotation of the rotor is stopped, and then the rotor 3 The fluid remaining inside the tank is discharged through the drain valve to the drain collector. And, as shown in Fig. 3, when the fixed rotor plate rotor 3-2 rises to the upper end by the rotor position change lifter 7, it is deposited between the variable rotor plate 3-11 and the fixed rotor plate 3-21. The solids are separated firstly and at the same time, the solids deposited on the fixed rotating plate can be scraped off by the solid separating plate attached to the upper side of the variable rotating plate. When the variable rotating plate rotor 3-1 is rotated at 300 to 1000 rpm, the variable rotating plate As shown in Figs. 8 and 9, the angular movement is free to drop the solids attached to the variable rotating plate (3-11). When the screw shaft 9 is reversely rotated so that the fixed rotating plate rotor 3-2 is lowered, the fixed rotating plate rotor 3-2 is again engaged with the variable rotating plate rotor 3-1. The fluid is then supplied again to separate the solids from the fluid. Solids separated from the rotor are discharged through the solids outlet opening at the bottom of the cylindrical housing. The discharge cycle of solids is determined by the formula below, depending on the nature of the fluid containing the solids.

* Note: Vs-amount of solids (equivalent to dry solids)

Q-process flow

Cs-solid concentration

Rv-Solid Removal Rate

As shown in Figs. 2 and 11, the fluid discharge device 2 is composed of a fluid discharge housing, a heavy fluid discharge pipe 12 and a light oil discharge pipe 13 attached to the upper surface of the fixed rotating plate housing (3-22). . In a strong centrifugal field, the fluid from which the solid particles are separated rises towards the axis of rotation and is layered, forming a concentric axis depending on the specific gravity of the fluid. Heavy fluid such as water is discharged to the heavy fluid discharge pipe 12 through the heavy fluid outlet (2-1), and light oil such as oil is light diesel discharge through the light fluid outlet (2-2). Discharged to (13). The fluid discharge device 2 rotates integrally with the rotor 3 and sprinkles the fluid in a fluid collection container attached to the outside of the cylindrical housing 1. The heavy fluid is discharged to the heavy fluid discharge pipe 12 disposed at the bottom of the fluid collection container (2-5), and the light oil is separated into the light fluid discharge pipe (13) disposed at the top of the fluid collection container (2-5). Is discharged.

As described above, the apparatus for separating the solid particles from the fluid has been described, but the scope of the present invention is not limited to the structure shown in the drawings, but is equivalent to all technical ideas within the scope equivalent to those described in the claims. You'll be crazy about it.

1: cylindrical housing
2: fluid discharge device
2-1: Heavy fluid outlet
2-2: light oil outlet
3: rotor
3-1: Variable rotor plate rotor
3-11: Variable rotating plate
3-12: Variable rotating plate fixing member
3-2: fixed turntable rotor
3-21: fixed turntable
3-22: fixed turntable housing
6-1: hollow part
5: spindle
6: axis of rotation
7: position change lifter
8: guide shaft
9: screw shaft
10: upper flange
11: lower flange
12: heavy fluid discharge pipe
13: light oil discharge pipe
14: Spline Hollow Shaft
15: sliding shaft

Claims

The rotor 3 is disposed inside the cylindrical housing 1, and the rotor 3 is composed of a variable rotor plate rotor 3-1 and a fixed rotor plate rotor 3-2, and a fixed rotor plate rotor 3-2. Is mounted on the position change lifter 7 mounted on the upper end of the cylindrical housing 1, and the sliding shaft 14 of the fixed rotor plate rotor 3-2 is the spline hollow shaft 15 of the variable rotor plate rotor 3-1. 6, the fixed rotor plate rotor 3-2 can be lifted and lowered relative to the variable rotor plate rotor 3-1 by the position change lifter 7, so that the sliding shaft 14 It can be moved up and down relative to the spline hollow shaft 15, the sliding shaft 15 is lowered, when the sliding shaft 14 is drawn into the spline hollow shaft 15, the fixed rotating plate rotor (3-2) The fixed rotating plate (3-21) of) is disposed between the variable rotating plate (3-11) of the variable rotating plate rotor (3-1), the sliding shaft 14 is raised For example, when the sliding shaft 14 is drawn out to the spline hollow shaft 15, the fixed rotating plate 3-21 of the fixed rotating plate rotor 3-2 is the variable rotating plate 3-11 of the variable rotating plate rotor 3-1. ), And the variable rotor plate rotor 3-1 is connected to the spindle 5 mounted at the lower end of the cylindrical housing 1 so that the rotational power of the spindle 5 is fixed to the variable rotor plate rotor 3-1. It is transmitted to the rotor plate rotor 3-2, and the hollow part is formed in the rotating shaft 6 of the spindle 5, and when the fluid is supplied to the rotor 3 through the hollow part of the rotating shaft 6, the rotor 3 rotates. The fluid is separated into sludge, heavy fluid and light oil, and the sludge is attached to the fixed rotating plate 3-21 and the variable rotating plate 3-11 of the rotor 3, and the heavy fluid and the light oil of the rotor 3 The rotary plate solid coalescing separator, characterized in that discharged to the heavy fluid discharge pipe 12 and the light oil discharge pipe 13 respectively through the fluid discharge device (2) mounted on the top.

The method of claim 1,
The spindle 5 is composed of a spindle housing 5-1 fixed to the cylindrical housing 1 and a rotating shaft 6 rotatably fitted to the spindle housing 5-1, and hollowed on the rotating shaft 6. In the state where the part 6-1 is formed and the upper end of the rotating shaft 6 is fitted to the rotor wheel 3-13, the flange plate 6-2 mounted on the upper end of the rotating shaft 6 is the rotor wheel 3. -13) rotating plate solids separator, characterized in that coupled to the lower surface.

3. The method of claim 2,
The rotor wheel 3-13 has a hole 3-15 through which the upper end of the rotating shaft 6 can be fitted, and a plurality of radially curved fluid dispersions around the hole 3-15 are formed. The rotary plate solid coalescing separator, characterized in that the groove (3-14) is formed, the lower end of the spline shaft (15) is disposed on the top of the fluid dispersion groove (3-14).

The method of claim 1,
The variable rotating plate rotor 3-1 is formed in a curved shape in which the variable rotating plate 3-11 is curved, and a cylindrical rotating shaft 3-16 is attached to an inner end of the variable rotating plate 3-11, The rotary shaft (3-16) is fitted into the vertical groove (3-17) of the variable rotating plate fixing member (3-12), a play is formed between the variable rotating plate (3-11) and the vertical groove (3-17). The variable rotation plate 3-11 can angularly move about the rotation shaft 3-16 by the play, and the spline hollow shaft 15 is fitted to the hollow portion of the variable rotation plate fixing member 3-12. The flange portion 15-2 formed at the lower end of the spline hollow shaft 15 is coupled to the rotor wheel 3-13 by bolts, so that the rotational force of the spindle 5 is splined hollow shaft 15 and the variable rotating plate. Rotary plate solids separator, characterized in that the transfer to the fixing member (3-12).

The method of claim 1,
The fixed rotor plate 3-2 has a curved or planar shape in which the fixed rotor plate 3-21 is curved, and an outer end of the fixed rotor plate 3-21 is formed on the inner circumferential surface of the fixed rotor plate housing 3-22. It is fixed at equal intervals, and the fluid discharge device 2 is mounted on the upper end of the fixed rotor plate housing 3-22, and the bearing member 14-5 is mounted below the upper end of the fixed rotor plate housing 3-22. And a bushing for supporting the fixed rotating plate rotor through the fluid discharge device 2 through the upper end of the sliding shaft 14 to the bearing member 14-5 and being supported by the upper end of the fixed rotating plate housing 3-22. (14-6) is mounted, the rotating plate solid coalescing separator characterized in that the movable plate (9-2) of the position change lifter (7) is mounted to the bushing (14-6).

6. The method according to claim 1 or 5,
The position shifting lifter 7 is equipped with an upper flange 10 on the upper end of the cylindrical housing 10, a screw shaft 9 and a guide shaft 8 driven by a motor is mounted on the upper flange 10, And a screw (9-1) are fastened to the screw shaft (9), and the nut (9-1) is mounted on the movable plate (9-2).