JPH10128158A - Centrifugal separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal separator in which even when the content of solid material in supplied mixed liquid is remarkably increased, the mixed liquid is smoothly separated into solid material having prescribed property and liquid and thereafter solid material and liquid are smoothly discharged to the outside. SOLUTION: A cylindrical body 11 and a screw conveyor 21 are formed respectively so that rotating power is given by exclusive motors 31, 41. Further, rotating speed Vs of the motor 41 for the screw conveyor is changed over by using an output frequency variable type invertor 46. Increase of sludge content RTs is detected as load (current Is) of the motor 41 for the screw conveyor. The rotating velocity of the motor 41 for the screw conveyor is rapidly and automatically changed over to differential velocity DV corresponding to detection load (Isd) by changing over the rotating speed of the motor 41 to the low speed side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a rotatable cylindrical body and a screw conveyor rotatable in the cylindrical body. It is formed to be able to be discharged into the outside while transferring the separated solid matter into the cylindrical body by using the difference speed between the rotation speed of the cylindrical body and the rotation speed of the screw conveyor as a reference while separating the solid matter into the solid body and the solid body. It relates to a centrifuge.

[0002]

2. Description of the Related Art Centrifuges for separating a liquid mixture of a liquid and a solid using a centrifugal force into the liquid and the solid are often used. In this centrifuge, a certain amount of the mixed liquid is supplied into a cylindrical body (drum) to separate the mixed liquid, and the separated liquid and solid are discharged to the outside, respectively, and then a new mixed liquid is discharged. It is well-known that there are a batch method in which the mixed liquid is supplied to perform the next separation, and a continuous method in which the mixed liquid is continuously supplied into the cylindrical body (drum) and the separated liquid and solid are continuously discharged respectively. .

For example, a centrifugal separator 10 for continuously separating and removing sludge (solid matter) such as paint residue from a mixed liquid (sewage) discharged from a painting booth of an automobile factory is shown in FIG. I will explain.

[0004] The mixed liquid TQ discharged from the painting booth 1
(Liquid RQ + Sludge SG) passes through pool 2 to pool 3
And a part thereof is continuously supplied to the centrifugal separator 10 via the pipe 4 and the pump 5. The sludge SG discharged from the centrifugal separator 10 to the outside
It is discarded in a predetermined place by using 0. The liquid (water) RQ discharged to the outside is returned to the pool 3 through the pipe 7. Or reused elsewhere.

[0005] The centrifugal separator 10 includes a rotatable cylinder 11 and a screw conveyor 21 rotatable in the cylinder 11, and the mixed liquid TQ supplied into the cylinder 11 is supplied to the cylinder 11. The liquid RQ is separated into the solid matter (sludge SG) using the rotational motion of the cylinder 11 and the rotational speed Vb in the rotational direction Rb of the cylindrical body 11 and the rotational speed Vs in the rotational direction Rs of the screw conveyor 21 as a reference. Differential speed DV
The sludge SG and the liquid RQ separated using (Vb−Vs) can be discharged to the outside.

More specifically, the sludge SG is discharged to the right side of the cylindrical body 11 in FIG.
An inclined portion 11S for preventing discharge of Q is provided, and a weir 11P for discharging liquid RQ to the liquid discharge pipe 18 side by overflow and preventing discharge of sludge SG is provided on the left side. The cylindrical body 11 is rotated by the rotating power of a motor 31P connected via a rotating shaft 12, a pulley 34P, a belt 33P, and a pulley 32P. The mixed solution TQ is supplied to a supply pipe 13 (supply ports 13A and 13B) penetrating through the rotation shaft 12.
Is supplied to the inside of the cylindrical body 11.

In FIG. 6, the supply ports (13A, 13B) are shown in simplified form for convenience of explanation.
2 are formed as a large number of through holes perforated in the peripheral surface.

The screw conveyor 21 comprises the above-mentioned rotary shaft 22 and a screw 23 having a spiral shape integrally fixed to the outer peripheral surface thereof. The screw 23 has a slight gap on the inner peripheral surface of the cylindrical body 11. The screw conveyor 21 is rotated by the rotation power of a motor 31P shared with the cylindrical body 11 via the rotation shaft 12, the gear mechanism 16, and the connection shaft 15. When the rotational speed Vb of the cylindrical body 11 is set as a reference, the differential speed DV where the rotational speed Vs of the screw conveyor 21 is lower than the rotational speed Vb is fixed (fixed). There is a gear mechanism 16 formed of a planetary gear mechanism so that the differential speed DV can be adjusted.

In the centrifugal separator 10 having such a configuration, the value of the mixed liquid TQ supplied per unit time Qtq and its concentration [sludge content rate RTs (for example, 1500 ppm)] is set as a value capable of smooth separation / discharge operation. , Cylindrical body 11
(For example, 3200 rpm) and the differential speed DV (for example, 10 rpm) [the rotation speed Vs of the screw conveyor 21 in this case is 3190 rpm], and the size (diameter and length) of the cylindrical body 11 is determined based on the rotation speed Vb. Etc.),
It is constructed by selecting the size and the like (diameter, number of sheets, etc.) of the screw conveyor 21, the capacity and the number of revolutions of the motor 31P, the specifications and structure of the gear mechanism 16, and the like.

Thus, a predetermined concentration, ie, sludge content rate RTs (for example, 15
00 ppm) of the mixed solution TQ in a predetermined amount Qt per unit time.
If only q is supplied, the sludge SG having a predetermined moisture content and the liquid RQ having a predetermined sludge content (for example, 50 ppm) can be separated smoothly. The separated sludge SG of, for example, 60 kg / h is transported smoothly to the right at a speed corresponding to the differential speed DV from the sludge discharge pipe 14 to the outside (10 g / h).
It is discharged smoothly to 0). Also, the separated liquid RQ is
The liquid is smoothly discharged to the outside (3) through the liquid discharge pipe 18 while overflowing the weir 11P.

[0011]

By the way, the supply amount Qtq of the mixed liquid TQ to be treated per unit time and the sludge (solid matter) content RTs may fluctuate, for example, by several%. ) Can be followed as an allowable range like other industrial machines. That is, it is a smooth operation possible range.

However, with the spread and diversification of the spread, there is a strong possibility that the following problems will occur.
Taking the case of the above-mentioned automobile factory as an example, the painting booth 1
For example, RTs = 150
When the operation is smoothly performed at 0 ppm, the sludge content RTs may greatly change to 3000 ppm, for example.

Then, the sludge content (property) of the separated liquid RQ excessively rapidly increases to, for example, 1100 ppm or continuously increases.
G is mixed in. Therefore, after the separation, the liquid RQ cannot be reused.

Conversely, the water content (properties) of the sludge SG changes significantly, which adversely affects the treatment after discharge. Further, if this state continues for a long time, the differential speed DV is constant, that is, the transfer speed of the separated sludge SG to the sludge discharge pipe 14 side is constant.
As time elapses, a large amount of sludge SG stays in the cylindrical body 11 to hinder smooth discharge, and furthermore, the screw conveyor 21, that is, the motor 31 </ b> P becomes overloaded, and the operation cannot be continued. If the timing of stopping the operation is delayed, the motor 31P may be burned or the screw 23 may be damaged.

An object of the present invention is to provide a centrifugal separator capable of smoothly separating and solidly discharging solids and liquids of a predetermined property even when the solid content of a supplied mixed liquid is greatly increased. To provide.

[0016]

SUMMARY OF THE INVENTION The principle of the centrifuge 10
When the function is confirmed again, the difference DV between the rotation speed Vb of the cylindrical body 11 and the rotation speed Vs of the screw conveyor 21 is obtained.
(= Vb−Vs) is constant and the mixed liquid T is supplied.
As long as the supply amount Qtq per unit time of Q is constant and the sludge (solid matter) content RTs is a predetermined value, the amount of sludge SG formed in the cylindrical body 11, that is, its thickness (ti) is , "T1" shown in FIG. However, if the sludge content rate RTs increases and continues, the thickness increases in the order of “t2”, “t3”, and “t4” in the order of FIGS. 1B, 1C, and 1D. Become. We believe that this is a factor that hinders the above-mentioned problem, that is, the superiority of the continuous method.

The transfer (discharge) speed of the separated sludge SG to the right in FIG. 6 by the screw conveyor 21 is proportional to the difference speed DV, and the transfer (discharge) of the screw conveyor 21 is performed. The magnitude of the power is naturally proportional to the amount of sludge transfer (discharge) per unit time. However, when a motor is used as a power source, if the capacity is fixed, the magnitude of the generated torque is inversely proportional to the magnitude of the rotation speed. That is, if the generated torque is reduced, the capacity (power) can be made constant even when the rotation speed is increased.

In view of this, the characteristics of the centrifugal separator 10 are reconsidered. Considering the case where the power applied to the screw conveyor 21 is fixed, the screw conveyor 21
Sludge transfer (discharge) speed by
When transferring (discharging) G by small amount and transferring (discharging)
In any case where a large amount of sludge SG is transferred (discharged) at a low speed, the sludge discharge amount (absolute value) per unit time that can be discharged to the outside should be the same.

Therefore, when the supply amount Qtq of the mixed liquid TQ to the cylinder 11 per unit time is constant, the sludge content rate RTs increases and changes, and the sludge thickness in the cylinder 11 becomes, for example, as shown in FIG. If it is known that "t3" shown in (C) has been reached or not and if the differential speed DV is increased before or after and the transfer speed of the sludge SG is increased, the thickness of the sludge SG becomes the same as (A). The reference "t1" shown can be returned immediately or over time.

To achieve this, the rotation speed Vs of the screw conveyor 21 is compared with the rotation speed Vb of the cylinder 11.
May be set to a lower speed, that is, a larger differential speed. In addition, by executing this, the torque generated by the screw conveyor motor, which has been temporarily increased or temporarily increased, can be returned to the original small value. That is, since the power can be made constant, the overload of the screw conveyor 21 can be prevented. In addition, the properties of the solid (SG) and the liquid RQ after separation can be kept constant.

However, the operator of the centrifuge 10 determines that the solid content RT
It is practically difficult to confirm the timing at which s increases by telephone, or to manually switch the differential speed DV in connection with the planetary gear mechanism each time, since it is complicated and requires a great deal of labor and time. is there. In the first place, it is difficult to allow the operator of the centrifuge 10 to be resident.

Thus, the present invention makes it possible to directly or indirectly detect an increase in the solid content of the mixed solution supplied into the cylinder as an increase in the load on the screw conveyor, and to detect the increase in the load when the increase in the load is detected. By switching the rotation speed of the screw conveyor motor to a lower speed side, the differential speed is increased to increase the transfer (discharge) speed of the separated solids, thereby suppressing an increase in the load on the screw conveyor and reducing the solids. It is formed such that solid-liquid separation and discharge to the outside can be carried out smoothly and stably while preventing the stagnation in the cylindrical body or eliminating the stagnation where the stagnation is about to occur.

That is, the present invention includes a rotatable cylindrical body and a screw conveyor rotatable within the cylindrical body. The mixed liquid supplied into the cylindrical body is subjected to liquid and solid material by utilizing the rotational movement of the cylindrical body. And a centrifugal separator formed so that solids separated by using the difference between the rotation speed of the cylindrical body and the rotation speed of the screw conveyor as a reference can be transported into the cylindrical body and discharged to the outside. In the above, the rotation power of the screw conveyor motor can be switched using an inverter of a variable output frequency so that rotation power can be applied to each of the cylindrical body and the screw conveyor by a dedicated motor, and a load of the screw conveyor can be switched. A rotational speed signal corresponding to the detectable and detected load signal is input to the inverter to switch the rotational speed of the screw conveyor motor. The solid content is smoothly discharged to the outside of the cylindrical body even if the solid content of the mixed liquid increases and changes by increasing the differential speed in accordance with an increase in the load of the screw conveyor. Are formed so as to be able to be held.

In this invention, the separation / discharge operation is performed by rotating the cylinder at a reference rotation speed by the motor for the cylinder and rotating the screw conveyor at a rotation speed capable of setting the reference differential speed by the motor for the screw conveyor. I do. During this separation / discharge operation, the load on the screw conveyor, that is, the increase in the solid content of the mixture supplied into the cylinder is indirectly detected, and a rotation speed signal corresponding to the detected load signal is input to the inverter. Thus, the rotation speed of the screw conveyor motor is switched and controlled.

That is, when the detected load increases,
The rotation speed of the screw conveyor motor is immediately switched to the low speed side, and the differential speed, that is, the transfer (discharge) speed of the separated solid matter, is switched to the high speed. Therefore, even if the solid content of the mixed liquid supplied to the cylinder increases and changes, retention of the separated solid in the cylinder is prevented in advance, or the solid property of the predetermined property is eliminated while being eliminated when it is about to be retained. Separation of solids and liquid and discharge to the outside can be maintained smoothly and stably, and if the differential speed is increased, the load on the motor for the screw conveyor can be suppressed to a lower level. You can drive.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) As shown in FIG. 2, the present centrifuge 10 has the same basic configuration (11, 21 and the like) as that of the conventional example (FIG. 6), and has the same structure as that of the painting booth 1 in an automobile factory. Although it is supposed to be used for wastewater treatment, each of the cylindrical body 11 and the screw conveyor 21 is connected to a dedicated motor 31,
The rotation speed Vs of the screw conveyor motor 41 is switchable by using an inverter 46 capable of applying rotation power and an output frequency variable type at 41, and is further provided with a load detection means (60), a storage means (53T) and a differential speed. Selection means (51,
52) and a differential speed switching control means (51, 52), and by increasing the differential speed DV corresponding to an increase in the load (current Is) of the screw conveyor 21, sludge (solids) of the mixed liquid TQ to be treated is obtained. Material) Even if the content RTs increases and changes, the solid matter (sludge SG) and the liquid RQ of a predetermined property (for example, a water content of 40%) and the liquid RQ are smoothly separated and smoothly discharged out of the cylindrical body 11 (maintained). It is formed to be possible.
That is, in the first embodiment, the load detecting means (60)
The rotational speed signal corresponding to the load signal detected in step is inputted to the inverter 46, and the screw conveyor motor 41 is rotated at the rotational speed determined as the relationship for increasing the differential speed in response to the increase in the load. ing.

Parts common to those in the conventional example (FIG. 6) are denoted by the same reference numerals, and description thereof is simplified or omitted.

In FIG. 2, the cylindrical body 11 is
2, rotational power is applied by a dedicated cylindrical motor 31 via a pulley 34, a belt 33, and a pulley 32. The load (current Ib) of the cylindrical motor 31 is:
It is driven almost constant. Therefore, this motor 3
1 has a smaller capacity than the conventional example (the shared motor 31P in FIG. 6). In this embodiment, as in the case of the screw conveyor 21 described later in detail, an inverter 36 capable of changing the output frequency by the set rotation speed signal Sb is provided, and the rotation speed Vb of the cylindrical motor 31 is also formed to be switchable.
The applicability to supply volume (Qtq) is expanded.

The screw conveyor 21 includes a transmission shaft 24, a pulley 44, a belt 43,
Rotary power is applied by a dedicated screw conveyor motor 41 via a pulley 42. The rotation speed Vs of the screw conveyor motor 41 can be switched using an output frequency variable inverter 46. Details are based on the switching speed signal Ss described later.

Note that a speed reduction mechanism may be provided between the screw conveyor motor 41 and the rotating shaft 22 so as to increase the resolution of the switching adjustment of the rotation speed Vs, that is, the switching adjustment of the differential speed.

The drive control unit 50 includes a CPU 51, R
The personal computer 10 includes an OM 52, a RAM 53, a keyboard (KB) 54, a display (IND) 55, an input port (IP) 56, and output ports (OPs) 57 and 58.

The storage means is the screw conveyor 2
(1) The relationship that increases (changes) the differential speed DV in response to the increase (change) in the load (i.e., the sludge (solid) SG and the liquid RQ even if the sludge (solid) content RTs of the mixed liquid TQ increases. This is a means for storing the differential speed switching data determined as a relationship that enables the smooth separation and the smooth discharge to the outside of the cylindrical body 11 to be stably held.
It is formed from the setting data table 53T shown in FIG. Note that the differential speed switching data can be applied to a subsequent decrease (change) of the once increased load of the screw conveyor 21.

Further, in the setting data table 53T,
The rotational speed Vb of the cylindrical motor 31 serving as a reference is also formed to be memorable. The rotation speed Vb is determined by the keyboard 54
When the rotation speed Vb is set, the control unit (CPU 51, ROM 52) outputs the set rotation speed signal Sb to the inverter 36 (ST11, ST12, ST14 in FIG. 4). It is formed with things.

The load detecting means is a screw conveyor 21
In this embodiment, the load current (Is) of the screw conveyor motor 41 shown in FIG.
It is formed from a current detector 60 for detecting d). That is, the load detecting means (60) indirectly detects an increase (change) in the sludge content rate RTs of the mixed liquid TQ to be processed. Decrease (change) can also be detected.

More specifically, when the differential speed DV is constant, that is, when the separated sludge SG is transported to the right in FIG. 2 at a constant speed, as the sludge content rate RTs increases, the cylinder 1
1, the thickness ti of the sludge SG is "t" shown in FIG.
1 "," t2 "," t3 "," t4 ", so that the load on the screw conveyor 21 increases, but it is extremely difficult to directly detect these thicknesses ti. The load of the screw conveyor 1 is quickly and automatically detected as the current consumption Is of the motor 41 for the screw conveyor.

The detected current value (load) Isd is CP
U5 and RAM5 are read in cooperation with U51 and ROM52.
3 is temporarily stored in the work area (ST1 in FIG. 4).
6). In this embodiment, during operation (YES in ST10)
Detecting operation is performed.

Here, the storage means (setting data table 5)
3T) is the load (current Is)
And rotation speed of screw conveyor motor 41 (Vs)
It is assumed to correspond to. Of course, it may be stored as a parenthesized differential speed (DV). In this case, it is necessary to ensure consistency between the differential speed (DV) and the switch setting rotation speed signal Ss.

FIG. 3 shows that the sludge content RsT is 1500
In ppm, the rotational speed Vb of the cylindrical motor 31 is set to 3200 rpm as a reference and the reference differential speed Vs is set to 10 rpm, and the thickness ti of the sludge SG in the cylindrical body 1 is shown in FIG.
Assuming that the temperature is maintained at “t1” shown in (A) (reference state), the sludge content rate RsT is 15
The currents (loads) at 00, 2250, and 3000 ppm are Is (10 A), Ih1 (13.5 A), and Is2
(17A) and the screw conveyor motor 41
The switch setting rotation speeds Vs, Vs1, and Vs2 of the
(= 10 rpm), DV1 (= 15 rpm), DV2
(= 20 rpm), 3190 rpm,
A case where the settings are stored as 3185 rpm and 3180 rpm is shown.

Note that each of the currents Is, Is1, Is2 includes
Although an allowable range (± α) is provided, it may be set and stored as a lower limit current and an upper limit current. In any case, it is desirable to set the detection current value Isd to be a continuous value as a whole so that the detection current value Isd belongs to one of the set storage current value ranges. Further, more difference speed switching data can be stored in the setting data table 53T, and each value can be changed using the keyboard 54.

The differential speed selecting means is a differential speed corresponding to the current (load) Isd of the screw conveyor 21 detected by searching the storage means (53T) (in this embodiment, the corresponding set switching rotational speeds Vs, Vs1). , Vs2), a ROM 5 storing a differential speed selection control program.
2 and the CPU 51, ST17 and ST18 in FIG.
YES at ST19. That is, any one corresponding to the detected current value Isd is selected (read) from the switching set rotation speeds Vs, Vs1, and Vs2 set and stored in the setting data table 53T.

The differential speed switching control means includes differential speed selecting means (5
1, 52) (YE in ST17 and ST18)
S, ST19) The switching setting rotation speed signal Ss corresponding to the difference speed (for example, Vs1) is output to the inverter 46, and the rotation speed of the screw conveyor motor 41 is switched (Vs → Vs1) to change the difference speed (DV1). ) Is established by the ROM 52 and the CPU 51 storing the differential speed switching control program, and is executed in ST20 of FIG.

Since the output frequency is switched by the inverter 46, the rotation speed (Vs) of the screw conveyor motor 41 can be rapidly switched to the low speed (Vs1). Accordingly, the sludge SG staying in the cylindrical body 11 tends from the state (“t1”) shown in FIG. 1A (“t1”) to the state (“t2”) shown in FIG. (A) ("t1") is only excessively and slightly increased ("t1 + α"). Therefore, the overload capacity of the screw conveyor motor 41 can be reduced, so that the size and cost can be further reduced.

The differential speed selecting means (51,
According to 52) and the differential speed switching control means (51, 52), if the sludge content ratio RTs increases and changes and the differential speed (DV) is once switched to, for example, DV1, and then the sludge content ratio RTs decreases and changes. The speed can be returned to the reference differential speed (DV) again (YES in ST18, ST15). In addition, even if the increase / decrease change of the sludge content rate RTs is temporary or continuous, it can follow.

When an operation start command is issued using the keyboard 54, the control program shown in FIG. 4 is driven and if the operation is not being performed (YES in ST10), the control unit (51,
52) reads out (selects) the set rotational speed Vb of the cylindrical motor 31 and the set rotational speed Vs of the screw conveyor motor 41 from the set data table 53T, and sets the set rotational speed to the corresponding inverters 36 and 46. Output the signals Sb and Ss respectively (ST11 to S11).
T15).

Next, the operation and operation of this embodiment will be described. When a driving start command is issued using the keyboard 54,
The control units (51, 52) search the setting data table 53T (ST11) to read out the reference setting rotational speeds Vb, Vs (ST12, ST13), and at the same time, read the inverter 3
The set rotation speed signals Sb and Ss are output to the CPUs 6 and 46, respectively (ST14, ST15).

Thus, the cylindrical motor 31 is rotationally driven at the reference rotational speed Vb (= 3200 rpm) (ST1).
4) The screw conveyor motor 41 is driven to rotate at the rotation speed Vs (= 3190 rpm) (ST15), so that a predetermined differential speed DV (= 10 rpm) can be obtained. The current Ib of the cylindrical motor 31 is constant.

Therefore, the standard sludge content R
If the mixed liquid TQ of Ts (1500 ppm) is supplied into the cylindrical body 11 by a predetermined supply amount Qtq per unit time, the liquid RQ having a predetermined property, that is, a predetermined sludge content (50 ppm) is obtained.
And sludge (solid matter) SG having a predetermined moisture content, and the separated sludge SG has a thickness “t1” shown in FIG. It is smoothly discharged to (100). The liquid RQ is also smoothly discharged to the outside (3).

Here, the sludge content rate RTs is, for example, 3
Considering the case where the sludge SG is increased to 000 ppm, the water content of the sludge SG that has been transiently separated is large, and the sludge SG is mixed in the liquid RQ and the sludge content is, for example, 110%.
It becomes 0 ppm. Further, when the increased sludge content RTs (= 3000 ppm) continues, the differential speed D
Since V (= 10 rpm) is constant, the separated sludge SG stays with the lapse of time and the thickness of the sludge SG is reduced as shown in FIG.
It faces the direction of “t3” shown in FIG. If this is left unchecked, an overload will occur, causing damage to the screw conveyor 21 and burning of the screw conveyor motor 41. Naturally, continuous operation becomes impossible.

However, in the present invention, during operation (S
At T10 (YES), the load detecting means (60) detects the load (current Isd) of the screw conveyor motor 41, and the control unit (51, 52) reads this to read the RAM5.
3 (ST16).

Thus, the differential speed selecting means (51, 52)
Searches the storage means (53T) shown in FIG. 3 (ST17).
Differential speed DV corresponding to the detected current value Isd (= 17 A)
2 (= 20 rpm) which corresponds to the switching set rotation speed Vs2
(= 3180 rpm) is selected (read) (NO in ST18, ST19). Then, the differential speed switching control means (51,
52) outputs a switching set rotation speed signal Ss corresponding to the selected differential speed equivalent rotation speed Vs2 to the inverter 46 shown in FIG. 2 and immediately switches the rotation speed of the screw conveyor motor 41 to Vs2 (= 3180 rpm) (ST2).
0). The differential speed is DV2 (= 20 rpm).

Therefore, since the transfer speed to the sludge discharge pipe 14 side can be increased, the thickness of the sludge in the cylindrical body 11 is temporarily increased while the sludge is being moved in the direction of “t3” shown in FIG. From the thickness ti (for example, “t2 + α”), the reference “t1” shown in FIG. During this period, the detected current value Isd is Is2 (17A) → Is1
(13.5A) → rapidly decreases toward Is (10A).

That is, the tendency is that the detected current value Isd
Becomes equal to Is1 (= 13.5 A) in the decreasing direction, the differential speed selecting means (51, 52) and the differential speed switching control means (51, 52) cooperate to reduce the differential speed to DV1. (= 15r
pm), and through this process, the reference load (I
s) can be returned to the differential speed DV (= 10 rpm). Therefore, the power applied to the screw conveyor 21 can be suppressed and made constant, so that a long-term overload can be prevented. The properties of the separated sludge SG and the liquid RQ can be returned to predetermined values except for a temporary transition.

When an operation stop command is issued using the keyboard 54 (YES in ST21), the controller (51, 5)
2) Stop the rotation of both motors 31, 41 (ST22).

According to this embodiment, the cylindrical body 11 and the screw conveyor 21 can be supplied with rotational power by the dedicated motors 31 and 41, and the motor for the screw conveyor can be provided by using the inverter 46 of a variable output frequency type. The rotation speed Vs of the motor 41 is switchable. Further, a load detecting means 60, a storage means (53T), a differential speed selecting means (51, 52) and a differential speed switching control means (51, 52) are provided, and the sludge is contained. The increase in the rate RTs is detected as an increase in the load (current Is) of the screw conveyer motor 41, and the rotational speed of the screw conveyer motor 41 is switched to a low speed to reduce the differential speed DV corresponding to the detected load (Isd). Since it is formed so that it can be switched automatically and quickly, the sludge (solid matter) content R of the mixed solution TQ
Even if Ts increases and changes, the solid material (SG) and the liquid RQ are stably maintained (maintained) by the smooth separation of the solid material (SG) and the liquid RQ and the smooth discharge of the separated solid material (SG) and the liquid RQ out of the cylinder 11. can do.

Further, since the load detecting means is formed by the current detector 60, the increase / decrease change of the sludge content rate RTs of the supplied mixed liquid TQ can be detected more quickly and accurately. From this point, it can be understood that the size and weight of the screw conveyor motor 41 and the cost can be reduced.

The variable output frequency inverter 46
Speed V of screw conveyor motor 41 using
s is rapidly changed, so that even if the sludge content rate RTs of the mixed liquid TQ suddenly changes, the thickness ti of the sludge SG after separation in the cylindrical body 11 is changed except for a temporary transition. It can be maintained at the reference thickness t1. Also from this point, the overload capacity of the screw conveyor motor 41 can be reduced.

The storage means is a setting data table 53
Since it is formed from T and each value is formed so as to be changeable using the keyboard 54, the applicability is wide.

Further, even after the differential speed selecting means (51, 52) and the differential speed switching control means (51, 52) have once switched the differential speed to, for example, DV2, the load (current Is) of the screw conveyor 21 is small. If possible, the speed difference can be returned to the reference (original) differential speed DV (YES in ST18, ST15), so that handling is easier.

Further, the setting data table 53T contains
Cylindrical motor 3 set and input using keyboard 54
1 can be stored, and the inverter 36 is provided so that the rotation speed Vb itself can be changed. Therefore, the supply amount Qtq of the mixed liquid TQ into the cylindrical body 11 per unit time is provided. Wide applicability to increase and decrease of

(Second Embodiment) A second embodiment is shown in FIG. Centrifuge 1 according to the second embodiment
0 indicates that a logic circuit 70 is provided so as to be switchable so that the rotation speed of the screw conveyor motor 41 becomes a rotation speed corresponding to the load signal detected by the load detection means (60). By increasing the differential speed DV in response to the increase in
Even if the solid content of Q) increases and changes, the solid cylinder 1
1 can be maintained smoothly.

Parts common to those in the conventional example (FIG. 6) and the first embodiment (FIG. 2) are denoted by the same reference numerals, and description thereof is omitted.

The logic circuit 70 includes a load detecting means (6
0), when the load (Isd) increases from the input, the switching setting rotational speed signal (Ss) determined to increase the differential speed DV in response to the load increase is output to the inverter 36. Have been. When the load (Isd) decreases, the logic circuit 70 outputs to the inverter 36 a switching setting rotational speed signal (Ss) determined to reduce the differential speed DV in accordance with the decrease in the load. It has been. In FIG. 5, 70
'Is a logic circuit that outputs the set rotation speed signal Sb to the inverter 36.

With this configuration, the control speed can be increased as compared with the first embodiment. Therefore, the differential speed DV can be increased more quickly, and the amount of solids remaining in the cylindrical body 11 can be returned to the reference state more quickly.

In the first and second embodiments, the load detecting means is formed by the current detector 60 which indirectly detects the load of the screw conveyor 21 as the current consumption Is of the screw conveyor motor 41. For example, a detector (not shown) that detects the voltage, frequency, and torque of the screw conveyor motor 41 may be used.
Further, it may be formed by a detector (not shown) for directly detecting the load of the screw conveyor 21.

[0065]

According to the present invention, the rotation power can be applied to each of the cylindrical body and the screw conveyor by a dedicated motor, and the rotation speed of the motor for the screw conveyor can be switched by using a variable output frequency inverter. And
An increase in the sludge content of the mixture is detected as a load on the motor for the screw conveyor, and the rotational speed of the screw conveyor is switched to a low speed side so that it can be quickly and automatically switched to a differential speed corresponding to the detected load. Therefore, the following excellent effects can be obtained.

When the solid content (concentration) of the liquid mixture to be treated is increased, the transfer speed of the separated solids in the discharge direction can be increased. That is, it is possible to automatically adjust the discharge amount of the solid matter suitable for the concentration. Therefore, since a large amount of solid matter does not stay in the cylindrical body, smooth separation and smooth discharge of the solid matter and the liquid can be stably maintained.

The solid-liquid separation and discharge can be performed in a standard state (steady state) or in a state close to this state only by increasing the differential speed by switching the motor for the screw conveyor to a low speed side. ) Can be stabilized, so that the subsequent processing can be performed stably, and the sludge content (property) of the separated liquid can be stabilized, that is, mixing of solids into the liquid can be prevented, so that stable reuse can be achieved.

[0068] Since it is possible to follow both temporary and continuous changes in the sludge content of the supplied liquid mixture, it is widely applicable and very easy to handle. further,
Once the sludge content of the increased mixture decreases, it can be automatically returned to the original state.

Since the speed difference can be rapidly increased by using the inverter, the transfer speed of the separated solid can be immediately increased, and the amount of the solid remaining in the cylinder can be immediately returned to the reference state. The load can be rapidly reduced. Therefore, a more stable operation can be achieved while preventing the screw conveyor from being overloaded for a long time.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the technical basis of the present invention.

FIG. 2 is an overall configuration diagram showing a first embodiment of the present invention.

FIG. 3 is a diagram for explaining a storage unit.

FIG. 4 is a flowchart for explaining the operation.

FIG. 5 is an overall configuration diagram showing a second embodiment of the present invention.

FIG. 6 is a diagram for explaining a conventional example and its problems.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Painting booth 3 Pool 10 Centrifuge 11 Cylindrical body 11S Inclined part 11P Weir part 12 Rotating shaft 13 Supply pipe 13A, 13B Supply port 14 Sludge discharge pipe 18 Liquid discharge pipe 21 Screw conveyor 22 Rotation axis 23 Screw 31 Motor for cylinder 36 Inverter 41 Screw conveyor motor 46 Inverter 50 Drive control unit 51 CPU (differential speed selection means, differential speed switching control means) 52 ROM (differential speed selection means, differential speed switching control means) 53 RAM 53T Setting data table (storage means) ) 54 keyboard 55 display 60 current detector (load detecting means) 70 logic circuit 100 carrier (external)

Claims (1)

[Claims] An apparatus includes a rotatable cylindrical body and a screw conveyor rotatable within the cylindrical body, and separates a mixed liquid supplied into the cylindrical body into a liquid and a solid using the rotational movement of the cylindrical body. A centrifugal separator formed to be able to be discharged to the outside while transferring solids separated by using the difference between the rotation speed of the cylindrical body and the rotation speed of the screw conveyor as a reference. The rotation power of the screw conveyor motor can be switched by using a variable output frequency inverter so that rotation power can be applied to each of the body and the screw conveyor by a dedicated motor, and the load of the screw conveyor can be detected and detected. The rotation speed signal corresponding to the load signal is input to the inverter, and the rotation speed of the screw conveyor motor is formed so as to be switchable, By increasing the differential speed in response to the increase in the load of the screw conveyor, even if the solid content of the mixed solution increases and changes, the solid can be smoothly discharged out of the cylindrical body. And a centrifuge.