JPS6320050A - Screw decanter type centrifgal concentrator - Google Patents

Abstract

PURPOSE:To obtain an optional concd. concn. and to prevent the clogging and the abrasion in a valve by providing a pump to either or both of discharge passages of separated liquid and concd. liquid to control amount of discharge. CONSTITUTION:The pump 19 driven by a motor 18 is provided to either or both of the discharge passages 15, 17 of the separated liquid and the concd. liquid in a screw decanter type centrifugal concentrator, and the amount of discharge is controlled by the pump 19 or a combined pipe 14. The control of the concn. of concd. liquid is carried out by changing the r.p.m. of the motor 18. The clogging and abrasion in the valve are eliminated thereby, and the control of the amount of discharge is easily carried out with high accuaracy. Moreover, as the pump is provided to the discharge side, the clogging caused by the stagnation of flow or the sedimentation of solid is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a screw decanter type centrifugal concentrator, in particular a cylindrical drum that rotates in one direction, and a drum that is coaxial with the drum and has a rotational difference within the drum. The solid content is separated and settled by centrifugal force from the suspension supplied into the drum through the support shaft during rotation, and the solid content is transferred to one side of the drum by the screw conveyor. This invention relates to a screw decanter type centrifugal concentrator that discharges a separated liquid from a hollow support shaft separately from the collected liquid.

Prior Art Conventional screw decanter type centrifugal concentrators generally have a nozzle on one side wall of the drum from which the concentrated liquid accumulated on the screw conveyor is discharged, and the nozzle is provided protruding around the side wall. Because the drum rotates with the drum, it is not possible to adjust the amount discharged from the nozzle during operation in response to fluctuations in the supply amount of suspension, solid content concentration, etc., and there is also power loss due to air resistance and the amount of discharged liquid It had various disadvantages such as a large loss of kinetic energy in one member.

In order to deal with this problem, a screw decanter type centrifugal concentrator of the above-mentioned type has been developed in recent years, in which the separated liquid and concentrated liquid are discharged through the inside or outside of a hollow support shaft, respectively. This is shown in Japanese Patent Publication No. 59-136152. According to this device, a regulating valve is provided at the outlet of the hollow support shaft to adjust the discharge amount, making it possible to make adjustments during operation. In addition, since the discharge position is close to the axis, less kinetic energy is wasted, and since there are no protrusions or openings on the side wall or outer peripheral wall of the drum, air resistance is small, resulting in less power consumption. .

Problems to be Solved by the Invention As mentioned above, the screw decanter type centrifugal concentrator of the above type uses the outlet of the hollow support shaft to adjust the discharge amount! I! By installing a regulating valve and adjusting its position in the axial direction, the gap between the hollow shaft outlet and the regulating valve is adjusted. However, when the gap is narrowed and the opening degree is reduced, the solid content is In the case of a concentrated liquid, it is particularly easy to clog, which can cause malfunctions, and since the support shaft rotates, there are other problems such as severe wear on the shaft end surface and the regulating valve.

Means for Solving the Problems The present invention has been made with the aim of solving the above problems, and the first invention is that in the screw decanter type centrifugal concentrator, either the separated liquid or the concentrated liquid is produced at a young age. This system is characterized in that pumps driven by motors are provided in both discharge paths, and the discharge amount is adjusted by changing the rotational speed of the motors or by using valves combined with the pumps.

The discharge path here includes not only the path outside the drum but also the path through which the separated liquid and concentrated liquid inside the drum exit the drum.

The pumps used are centrifugal pumps, axial flow pumps, reciprocating pumps, positive displacement pumps, etc., which can be used alone or in combination with valves. A positive displacement pump such as a gear pump, screw pump, or Roots pump is preferably used alone as the pump for adjusting the discharge amount of the concentrated liquid.

The second invention uses a level difference between the inside and outside of a hollow support shaft to create a level difference between the liquid levels of the discharged N liquid and concentrated liquid, and is driven by a motor in the suspension supply path. By providing a pump and changing the rotation speed of the motor, or by using a valve combined with the pump, Q if3? The present invention is characterized in that the discharge amount of the separated liquid and the concentrated liquid is adjusted by changing the supply amount of &.

The pumps used here are generally pumps such as centrifugal pumps, axial flow pumps, reciprocating pumps, positive displacement pumps, etc., and are used alone or in combination with valves.

The embodiment drum 1 has a hollow shaft 2 that protrudes from side to side, and bearings 3.
A pulley 4 is attached to the hollow shaft 2 on the supply side, and is driven by a belt from a drive source (not shown).

The drum 1 also has a built-in screw conveyor 8 equipped with screw blades 7 on the outer periphery of a cylindrical body 6, and hollow shafts 9 protruding from both left and right sides respectively protrude through the hollow shaft 2, and are rotated by bearings 11 at the protruding ends. It is pivoted. A pulley 12 is fixed to the hollow shaft 9 on the supply side, and is driven by a belt from the drive source so as to rotate in the same direction as the drum with a rotational difference.

The shell 6 further includes a pipe 1 passing through the hollow shaft 9 on the discharge side.
4 protruding from the side to form a double pipe structure with the hollow shaft 9,
In addition, a plurality of radial passages 15 communicating with the hollow shaft 9 are provided on the left and right side walls, and a conduit 17 extending radially from the pipe 14 is provided along the drum side walls. The pipe 14 protruding from the hollow shaft 9 is also connected to a pipe 20 provided on the suction side of a single screw pump 19 driven by a motor 16 so as to be rotatable relative to the pipe 20.

Although not shown, the spaces between the hollow shaft 2 and the hollow shaft 9, between the hollow shaft 9 on the discharge side and the discharge passage 22, between the pipe 14 and the pipe 20, etc. are sealed by mechanical seals. This is to prevent the liquid and tJF outlet 7& from leaking outside.

This device is constructed as described above, and the suspension supplied from the hollow shaft 9 on the supply side enters the drum 1 through the flow path 11, and the solid content is separated by the centrifugal force caused by the rotation of the drum.
Let it settle. The concentrated liquid containing solids that settles on the inner circumferential wall of the drum is scraped to the discharge side by a screw conveyor 8 that rotates in the same direction as the drum with a rotational difference, and is passed through the pipe line 17.
The pipe 14 and the pipe 20 are pumped up by 1f.
fl, and is discharged via pump 19. On the other hand, the separated liquid from which the solid content has been separated is discharged from the flow path 15 on the discharge side, through the hollow soyaft 9, and through the discharge path 22. While the separated liquid and concentrated liquid pass through the flow path 15 and pipe 17 on the discharge side, their kinetic energy is used as part of the driving power for the screw conveyor and drum.

When adjusting the concentration concentration of the concentrated liquid, it is done by changing the rotation speed of the motor 18 and adjusting the discharge amount.
If the tf1 degree increases and the discharge amount increases, the concentrated concentration decreases.

The embodiment shown in FIG. 2 is different from the embodiment shown in FIG.
The pump 19 is omitted and a discharge path 23 is provided at the end of the pipe, and the flow path 15 on the discharge side is communicated with the pipe 14 so that the separated liquid is discharged through the pipe. The roots pump 24 is driven by a gear transmission 25 provided on the outer wall of the drum, and the concentrated liquid is discharged through the roots pump 24 and between the hollow shaft 9 and the pipe 14. can be adjusted.

The embodiment shown in FIG. 3 is different from the embodiment shown in FIG.
The pump 19 is omitted and a discharge path 23 is provided at the end of the pipe, and the hollow shaft 9 on the supply side is connected to the discharge side of the centrifugal pump 27, and a flow rate control valve 28 is provided on the supply path. The discharge amount is adjusted using the level difference between level A and discharge level B of the separated liquid. In other words, when the flow ff111 control valve 28 is throttled to reduce the supply amount of the suspension, the separated liquid is discharged only from between the hollow shaft 9 and the pipe 14, and when the supply amount is increased, part of the separated liquid becomes A. The amount exceeds the amount and is also discharged from the pipe 14, and as the amount of supply increases, the amount of discharge from the pipe also increases. However, the concentrated liquid 41i! The concentration varies depending on the amount of suspension supplied.

Effects of the Invention The first invention provides a pump in the discharge path of either or both of the separated liquid and the concentrated liquid, and adjusts the discharge amount by the pump alone or by a pipe combined with the pump, thereby achieving the desired concentration concentration. Compared to the conventional method, which has a valve facing the end of the discharge path and adjusts the amount of discharge by adjusting the gap between the valve and the end of the discharge path, the amount of discharge is lower. Even if the amount of water is reduced, the clogging and wear of valves that tend to occur with conventional valves is eliminated or can be eliminated, and the amount of discharge can be adjusted more accurately and easily, making control easier. become. Moreover, since the pump is installed on the discharge path side, the flow will not stagnate even if the supply amount of suspension decreases or the pressure in the discharge path decreases.
It is also possible to eliminate clogging in the discharge path caused by 4fi.

In the second invention, a pump is provided on the supply path side of the suspension, and the discharge amount is adjusted by the pump alone or by a valve combined with the pump, and the valve is provided in the discharge path. Since the valve is not sealed, there is no possibility of wear and tear caused by clogging of the valve as in the case of conventional valves.

[Brief explanation of drawings]

The figures show a screw decanter type centrifugal concentrator according to the present invention. Figure 1 is a schematic diagram of the first embodiment, Figure 2 is a schematic diagram of the second embodiment, and Figure 3 is a schematic diagram of the third embodiment. It is a schematic diagram.

Claims (2)

[Claims] (1) It has a cylindrical drum that rotates in one direction and a screw conveyor that is coaxial with the drum within the drum and rotates in the same direction with a rotational difference, and supplies are supplied into the rotating drum. Screw decanter type centrifugal concentration in which solids are separated and sedimented from the suspension by centrifugal force, accumulated on one side of a drum by a screw conveyor, and discharged from a hollow support shaft separately from the separated liquid. In the machine, a pump is installed in the discharge path of either or both of the separated liquid and the concentrated liquid containing solids, and the discharge volume is adjusted by the pump or by a valve combined with the pump, and the concentrated concentration is adjusted. Screw decanter type centrifugal concentrator (2) It has a cylindrical drum that rotates in one direction and a screw conveyor that is coaxial with the drum within the drum and rotates in the same direction with a rotational difference, and supplies are supplied into the rotating drum. Screw decanter type centrifugal concentration in which solids are separated and sedimented from the suspension by centrifugal force, accumulated on one side of a drum by a screw conveyor, and discharged from a hollow support shaft separately from the separated liquid. In the machine, the separated liquid and the concentrated liquid are discharged through the inside and outside of the support shaft, respectively, and a pump is provided in the supply path of the suspension liquid, and the suspension liquid is discharged by or in combination with the pump. A screw decanter type centrifugal concentrator that adjusts the supply amount using a valve and uses the difference in discharge level between the separated liquid and concentrated liquid to adjust the concentrated concentration.