JPH0623590A - Screw press system compression method and screw press type compression machine - Google Patents

Abstract

PURPOSE:To prevent the phenomenon of sludge co-rotation from generating even in the case that a little amount of the sludge is changed. CONSTITUTION:Because, when a detected value of a thrust load and a torque is larger in comparing with a set value, an opening ratio becomes large by pulling out a plumb like ring 7 from a compressed subject discharging hole 6, and reversely when the detected value is smaller than the set value, the opening ratio becomes small by inserting the plumb like ring 7, so the opening ratio is made small when the sludge being charged in a sludge supplying hole 1 becomes little. Because a position detector 19 detecting the position of the plumb like ring 7 and a lower limit value keeping means 14 keeping the opening ratio of the compressed subject discharging hole 6 over the prescribed value are provided, the plumb like ring 7 is not inserted so as to be lower than the set lower limit opening ratio and the co-rotation of the compressed subject is not generated.

Description

Detailed Description of the Invention

[0001]

This invention relates to solid-liquid mixtures, especially
Sludge generated when treating water, wastewater, and other liquids,
An organic polymer coagulant, a sludge coagulated by adding another coagulant to these sludges, or a sludge such as an oil-containing sludge is continuously squeezed and dehydrated or deoiled with a screw blade to squeeze the filtrate, and the water content remarkably Alternatively, the present invention relates to a screw press type pressing method and a screw press type pressing machine for producing a pressed product having a low oil content.

[0002]

2. Description of the Related Art Conventionally, when a screw press type compressor is applied to, for example, sludges, basically, as shown in FIGS. 2, 3 and 4, the sludge supply port of the sludge hopper 2 is basically used. 1 and an outer cylinder 3 of a cylindrical filter medium provided between the compressed product discharge port 6
And a screw shaft 5 having a screw blade 4 on the outer circumference
And a weight ring 7 (referred to as a taper cone or a rotating cone) concentrically provided with the screw shaft 5 on the compressed product discharge port 6 side, and moreover, the outer cylinder 3, the screw shaft 5, and the screw blade. The volume of the annular gap formed by 4 is appropriately reduced sequentially, and the sludge fed into the sludge supply port 1 is pushed out in the axial direction by the rotation of the screw shaft 5, that is, toward the compressed product discharge port 6, and is squeezed sequentially. The filtrate squeezed out of the sludge is discharged from the outer cylinder 3, and the dehydrated compressed product is taken out from the compressed product discharge port 6. In addition,
The term “dehydration” is used below to include “deoiling”.

Further, various improvements have been made to the press in order to enhance the pressing effect. For example, in the compressor shown in FIG. 2, the drive shaft 8 driven by the drive device 12 is connected to the screw shaft 5, and the weight ring 7 having the drive device 9 is reciprocally attached to the drive shaft 8. Furthermore,
The thrust gauge 10 for detecting the thrust load applied to the screw shaft 5 is attached to the drive shaft 8, and the drive device 9 is interlocked with the detection value of the thrust gauge 10 to push or pull the weight ring 7 into or out of the compressed material discharge port 6. The squeeze pressure is adjusted by adjusting the opening ratio of the squeezed material discharge port 6 and changing the resistance given to the sludge at the time of discharging the sludge, and has a structure and function to obtain an arbitrary water content. . The term “water content” is used below to mean “oil content”.

Further, the compressor shown in FIG.
A drive shaft 8 driven by 2 is connected to a screw shaft 5, a weight ring 7 having a drive device 9 is reciprocally attached to the drive shaft 8, and a torque meter for detecting a torque applied to the screw shaft 5 is further provided. 11 is attached to the drive shaft 8, and the drive device 9 is interlocked with the detection value of the torque meter 11 to push or pull the weight ring 7 into or out of the squeezed material discharge port 6 to adjust the opening ratio of the squeezed material discharge port 6. The squeezing pressure is adjusted by changing the resistance given to the sludge when the sludge is discharged, and the structure and function are such that an arbitrary water content can be obtained.

The squeezing machine shown in FIG. 4 has the functions of the squeezing machine shown in FIGS. 2 and 3, and has a driving device 9 in which a driving shaft 8 driven by a driving device 12 is connected to a screw shaft 5. The weight ring 7 is attached to the drive shaft 8 so as to be reciprocally movable, and the thrust load and the torque applied to the screw shaft 5 are detected by the thrust meter 10 and the torque meter 11, respectively, and the arithmetic and control unit 13 which calculates these detected values is detected. The driving device 9 which operates by the control signal output from the arithmetic and control unit 13 is attached to the weight ring 7, and the weight ring 7 is pushed into or pulled out from the weight discharge port 6 according to the control signal. The squeeze pressure is adjusted by adjusting the opening ratio of the discharge port 6 and changing the resistance given to the sludge at the time of sludge discharge so that an arbitrary water content can be obtained. And it has an elephant and function. An example of such a screw press type squeezing machine is Japanese Utility Model Sho 62-4.
There is one disclosed in Japanese Patent No. 5831.

By the way, generally, in the press dehydration of sludge, the unit filtration area A, the amount V of filtrate produced per unit time θ, that is, the filtration rate, increases as the pressure P applied to the compressed product increases. It holds. (1 / A) · (dV / dθ) = ΔP / (μ · R) where μ is the viscosity of the filtrate and R is the resistance of the filtrate. Therefore,
When it is desired to increase the filtrate velocity, it is necessary to increase the pressure applied to the pressed product.

In the case of a screw press type compressor, as described above, the water content of the compressed product produced and the screw drive shaft 8
The relationship of the thrust load, torque, etc. applied to the oil tends to be inversely proportional as these values increase as the water content of the dehydrated pressed product decreases. That is, the weight ring 7 is further inserted into the outer cylinder 3 by setting the set value of the thrust meter 10 or the torque meter 11 as shown in FIGS. The opening ratio of the outlet 6 becomes small, and as a result, when sludge is discharged, a large resistance is exerted on the sludge, which increases the squeezing pressure applied to the sludge and reduces the water content of the dehydrated squeezed product produced.

[0008]

[Problems to be Solved by the Invention]
Regarding the screw press type compressor, when the degree of insertion of the weight ring 7 is suddenly increased to reduce the opening rate of the squeezed material discharge port 6 in a short time, or the insertion rate is excessively decreased, the opening rate becomes extremely small. In this case, only the sludge near the squeezed material discharge port 6 has a reduced water content, or the resistance applied when sludge is discharged becomes too large, so that the sludge is not discharged from the squeezed material discharge port 6 and the screw is discharged. The rotation of the shaft 5 causes a so-called co-rotation phenomenon of sludge in which the sludge rotates together with the screw shaft 5.

When the co-rotation phenomenon occurs, the sludge does not move in the direction of the compressed product discharge port 6 but simply rotates on the spot together with the screw shaft 5, so that the thrust load becomes small. In addition, since the sludge continues to be continuously fed from the sludge supply port 1 without discharging the dehydrated pressed product, the sludge gradually flows into the annular gap formed by the outer cylinder 3, the screw shaft 5 and the screw blades 4. , Which increases in proportion to the amount of sediment, regardless of the water content of the dehydrated pressed product.

For example, in the conventional screw press type compressor shown in FIG. 2, when the co-rotation phenomenon of sludge occurs, the thrust load value detected by the thrust meter 10 becomes small, so that the drive device for the weight ring 7 is reduced. 9, the weight ring 7 is inserted into the compressed product discharge port 6. When the squeezed product co-rotation phenomenon occurs, the weight ring 7 should be pulled out from the squeezed product discharge port 6 to increase the opening ratio of the squeezed product discharge port 6 so that the squeezed product is easily discharged. Since the thrust load value detected by the thrust gauge 10 is small, the weight ring 7 is inserted into the squeezed material discharge port 6, and the opening ratio of the squeezed material discharge port 6 is further reduced. For this reason, it becomes impossible to discharge the squeezed material,
The co-rotation phenomenon of sludge more strongly occurs, and the dehydrated compressed product is not discharged from the compressed product discharge port 6 at all, and operation becomes impossible.

In the screw press type compressor shown in FIG. 3, when the co-rotation phenomenon of sludge occurs, the amount of dehydrated compressed product discharged from the compressed product discharge port 6 decreases,
Since a certain amount of sludge to be fed to the sludge supply port 1 continues to be fed, the amount corresponding to the difference between the amount of sludge fed and the amount of dewatered pressed product is gradually increased by the outer cylinder 3, the screw shaft 5, and the screw blade 4. The torque value detected by the torque meter 11 is increased in proportion to the amount of the accumulated gas accumulated in the annular gap formed by.
As a result, the drive device 9 of the weight ring 7 is interlocked with the weight ring 7 and the weight ring 7 is pulled out from the squeeze discharge port 6, and the opening ratio of the squeeze discharge port 6 is set to be large. But,
Since the torque detected by the torque meter 11 gradually increases, the weight ring 7 is gradually pulled out from the compressed product discharge port 6, and the co-rotation phenomenon of sludge is not easily resolved. Alternatively, even if it is eliminated, while the sludge accumulation amount in the annular gap formed by the outer cylinder 3, the screw shaft 5 and the screw blades 4 is large, the weight ring 7 is pulled out from the squeeze discharge port 6 because the torque is large. Since the opening ratio of the squeezed material discharge port 6 is large, there is a problem that a large amount of dehydrated squeezed material having a high water content is continuously discharged from the squeezed material discharge port 6 during this period.

In the conventional screw press type compressor shown in FIG. 4, when the amount of sludge fed to the sludge supply port 1 becomes small, an annular gap formed by the outer cylinder 3, the screw shaft 5 and the screw blades 4 is formed. Since the amount of sludge to the squeeze is reduced, the values such as the thrust load and torque detected by the thrust meter 10 and the torque meter 11 are reduced, and the weight ring 7 is inserted into the squeezed material discharge port 6 to discharge the squeezed material. The aperture ratio of the outlet 6 becomes very small. When the opening ratio is very small as described above, even if the weight ring 7 is slightly moved, the opening ratio of the compressed product discharge port 6 is large. Therefore, it is difficult to adjust the discharge amount of the compressed product. Has become a cause of.

Therefore, an object of the present invention is to economically and effectively solve the above problems in the conventional screw press type press, and to prevent the occurrence of co-rotation phenomenon of sludge and a screw press type pressing method. It provides a mold press.

[0014]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention is introduced into an annular gap formed by an outer cylinder of a cylindrical filter medium having a sludge supply port and a compressed product discharge port, and a screw shaft having screw blades arranged in the outer cylinder. The mud is squeezed and dehydrated by the rotation of the screw shaft and discharged from the squeezed material discharge port, and the thrust load and torque applied to the screw shaft are detected to open the squeezed material discharge port based on the detected value. In the screw press type compression method of changing the ratio, the screw press type compression method is characterized in that the opening ratio is controlled so as not to become smaller than a set lower limit opening ratio.

Alternatively, according to the present invention, a screw shaft having screw blades is rotatably arranged in an outer cylinder of a cylindrical filter medium having a sludge supply port and a compressed product discharge port, and the outer cylinder, the screw shaft and the A cone-shaped ring for gradually reducing the volume of the annular gap formed by the screw blades toward the squeezed material discharge port, reciprocating along the screw shaft by the driving device, and adjusting the opening ratio of the squeezed material discharge port. Attached concentrically to the screw shaft, a thrust meter for detecting a thrust load applied to the screw shaft and a torque meter for detecting torque are provided, and the detection value detected by the thrust meter and the torque meter is calculated to calculate the weight ring. In a screw press type squeezing machine provided with an arithmetic and control unit for controlling the driving device, the opening for setting the lower limit opening ratio of the squeezed material discharge port. A screw press type compressor characterized by comprising a rate setting device, a position detector for detecting the position of the weight ring, and a lower limit value maintaining means for maintaining the opening ratio of the compressed material discharge port at a predetermined value or more. .

In this screw press type compressor, the lower limit value maintaining means may be given as a program incorporated in the arithmetic control device, or the lower limit value maintaining means may be provided independently of the arithmetic control device. It may be configured to operate.

In the screw press type compressor, when the lower limit value maintaining means is given as a program incorporated in the arithmetic and control unit, specifically, the arithmetic and control unit detects the thrust gauge and the torque meter. Load comparison that compares the load detection value with the load setting value, and issues a first signal when the load detection value is greater than the load setting value, and issues a second signal when the load detection value is less than or equal to the load setting value. Means, aperture ratio calculation means for calculating the aperture ratio when the weight ring is inserted by a predetermined distance from the position of the weight ring detected by the position detector by the input of the second signal, and the aperture ratio calculation means The calculated aperture ratio is compared with the lower limit aperture ratio set by the aperture ratio setting device, and when the calculated aperture ratio is larger than the lower limit aperture ratio, a third signal is emitted, and the calculated aperture ratio is Aperture ratio comparing means for issuing a fourth signal when the lower limit aperture ratio is smaller, opening the conical ring when the first signal is input, and closing the conical ring when the third signal is input. The drive control means may be configured to operate so as to close the weight ring when the fourth signal is input and stop the weight ring at a position where the lower limit aperture ratio is reached.

Since the lower limit opening ratio varies depending on the properties of the target sludge, a preliminary experiment using the sludge, a method of determining the limit from the thrust and torque load characteristics of the screw press type compressor, and other suitable methods The lower limit aperture ratio may be appropriately selected by any means so that the compressed product is always discharged from the compressed product discharge port.

[0019]

Since the present invention is constructed as described above, it operates as follows. In the screw press type compressor according to the present invention, the thrust load and the torque detected are compared with the set value because the thrust load and the torque detected on the screw shaft are calculated and the drive control of the conical ring is performed. When the size is large, the weight ring is pulled out from the squeezed material discharge port for a predetermined distance and the opening ratio increases,
On the contrary, when the detected value is smaller than the set value, the weight ring is inserted into the squeezed material discharge port for a predetermined distance to reduce the aperture ratio, but the aperture ratio setting device for setting the aperture ratio of the squeezed material discharge port, the weight. Since the position detector for detecting the position of the ring-shaped ring and the lower limit value maintaining means for maintaining the opening ratio of the compressed material discharge port at a predetermined value or more are provided, the opening for calculating the detected values such as the thrust load and torque applied to the screw shaft The aperture stops at the aperture ratio setting device, and the aperture ratio does not decrease any further. Therefore, this screw press-type press does not cause a co-rotation phenomenon of the squeezed product because the opening ratio does not become extremely small even when the amount of mud that is input to the sludge supply port decreases. It is possible to continue stable operation.

Further, according to the screw press type squeezing method of the present invention, since the opening ratio is controlled so as not to become smaller than the set lower limit opening ratio, when the amount of the mud-like substance put into the sludge supply port becomes small. However, the aperture ratio does not become extremely small. Therefore, in this screw press type squeezing method, a co-rotation phenomenon of the squeezed material does not occur, and stable operation can be continued.

[0021]

Embodiments of the screw press type pressing method and screw press type pressing machine according to the present invention will be described below with reference to the drawings. Of course, the embodiments of the present invention are not limited to these. FIG. 1 is a vertical sectional side view showing an embodiment of this screw press type compressor.

This screw press type compressor has a conical shape in which a screw blade 4 is provided on the outer periphery in an outer cylinder 3 of a cylindrical filter medium having a sludge supply port 1 of a sludge hopper 2 and a compressed product discharge port 6. A screw shaft 5 is rotatably arranged. A weight ring 7 is concentrically and reciprocally mounted on a drive shaft 8 connected to the screw shaft 5 on the side of the compressed product discharge port 6, and the weight control ring 1 is attached to the weight ring 7.
A drive device 9 which is operated by a control signal output from 3 is attached. Moreover, a thrust gauge 10 is attached to the drive shaft 8 of the screw shaft 5, and a torque gauge 11 is attached to the drive device 12 of the screw shaft 5, and the detected values of these are input to the arithmetic and control unit 13 for a predetermined time. It is calculated for each time, and the result is output as a control signal to the drive device 9 at regular intervals. Then, according to this control signal, the drive device 9 causes the weight ring 7 to move.
Is inserted into or pulled out from the compressed product discharge port 6. Also, a position detector 1 for detecting the position of the weight ring 7
9 is provided, and the detection value detected by the position detector 19 is input to the arithmetic and control unit 13. Also, the weight ring 7
The lower limit value maintaining means 14 is provided so that when the product is inserted into the compressed product discharge port 6 to a predetermined position, it cannot be inserted any more.

As the lower limit value maintaining means 14, various embodiments such as one that operates independently of the arithmetic and control unit 13 and one that is set as a program on the arithmetic and control unit 13 can be considered. As a device that operates independently of the arithmetic and control unit 13, for example, a position-adjustable stopper that restricts the insertion of the weight ring 7 into the squeezed material discharge port 6 and a transmission mechanism of the drive unit 9 are incorporated. It is conceivable that it is composed of a torque limiter. Here, the stopper corresponds to the position detector 19 in this screw press type compressor, and the torque limiter corresponds to the lower limit value maintaining means 14.

When the weight ring 7 is inserted into the squeezed material discharge port 6 to a predetermined position, the weight ring 7 contacts the stopper, which overloads the torque limiter and causes the drive device 9 Power transmission was cut off, and as a result,
The conical ring 7 stops moving. A control signal for pulling out the conical ring 7 is transmitted from the arithmetic and control unit 13 to the drive unit 9
When the input signal is input to the drive device 9, the drive device 9 rotates in reverse, so that the torque limiter is drivingly connected to transmit the power from the drive device 9 to the weight ring 7, and the weight ring 7 is pulled out. In this example, the arithmetic and control unit 13 can be the same as the conventional one.

Next, an example in which the lower limit value maintaining means 14 is set as a program on the arithmetic and control unit 13 will be described with reference to the block diagram of FIG. The setter 15 is installed in the torque meter 11 and can set the torque arbitrarily. The torque setter 16 and the thrust meter 10
In addition to the thrust setting device 17 installed in the above which can arbitrarily set the thrust load, an opening ratio setting device 18 which can arbitrarily set the lower limit opening ratio of the compressed product discharge port 6 is provided. The opening ratio setting device 18 can be changed even during operation when the lower limit opening ratio is desired to be changed according to the property of sludge or the property of dewatered pressed product. In this respect, other setting devices 16, 17 can be used. Is also the same. Further, a position detector 19 for detecting the position of the weight ring 7 is provided.

The lower limit maintaining means 14 incorporated in the arithmetic and control unit 13 comprises a load comparing means 20 and an aperture ratio calculating means 2.
1, an aperture ratio comparing unit 22, and a drive control unit 23. The load comparison means 20 compares the load detection value detected by the trust meter 10 and the torque meter 11 with the load setting value set by the trust setting device 17 and the torque setting device 16, and the load detection value is larger than the load setting value. The first signal is sometimes emitted, and the second signal is emitted when the load detection value is equal to or less than the load set value. The aperture ratio calculator 21 calculates the aperture ratio when the weight ring 7 is inserted by a predetermined distance from the current position of the weight ring 7 detected by the position detector 19. The aperture ratio comparing unit 22 compares the calculated aperture ratio calculated by the aperture ratio calculating unit 21 with the lower limit aperture ratio set by the aperture ratio setting unit 18, and issues a third signal when the calculated aperture ratio is larger than the lower limit aperture ratio. ,
The fourth signal is emitted when the calculated aperture ratio is smaller than the lower limit aperture ratio. The drive control means 23 opens the weight ring 7 when the first signal is input, closes the weight ring 7 when the third signal is input, and drives the weight ring 7 when the fourth signal is input. The drive device 9 is controlled so that the ring 7 is closed and stopped at a position where the lower limit aperture ratio is reached.

The sludge thrown into the sludge hopper 2 flows into an annular gap formed by the outer cylinder 3, the screw blades 4 and the screw shaft 5, and is conveyed to the squeezed material discharge port 6 by the rotation of the screw shaft 5 while being annularly formed. It is gradually squeezed due to the reduction of the volume of the gap, and is discharged from the squeezed material discharge port 6 as a squeezed material that is gradually dehydrated while discharging the filtrate from the outer cylinder 3. At that time, since the sludge introduced from the sludge hopper 2 into the annular gap formed by the outer cylinder 3, the screw blades 4, and the screw shaft 5 is conveyed to the squeezed material discharge port 6 side by the rotation of the screw shaft 5, the screw is discharged. Thrust load or torque is applied to the shaft 5, the thrust load is detected by the thrust meter 10, and the torque is detected by the torque meter 11.

Usually, when the amount of sludge put in the press is constant and the co-rotation phenomenon of the sludge does not occur, the screw shaft 5 is normally conveyed by the rotation of the screw shaft 5 to the side of the compressed product discharge port 6, When either the thrust load set value of the thrust meter 10 or the torque set value of the torque meter 11 is increased, the set value is input to the arithmetic and control unit 13, and the arithmetic and control unit 1
A control signal is sent from 3 to the driving device 9, which causes the driving device 9 to operate and the weight ring 7 to be inserted into the squeezed material discharge port 6 to set the opening ratio of the squeezed material discharge port 6 to a smaller value.

Therefore, when the dehydrated squeezed material is discharged, the resistance applied to the squeezed material is further increased, the squeezing pressure on the sludge in the annular gap is increased, and more filtrate is discharged from the outer cylinder 3, The water content of the obtained dehydrated pressed product and sludge in the annular gap gradually decreases. Along with this, since hard sludge is discharged from the compressed material discharge port 6 having a small opening ratio, a larger thrust load or torque is applied to the screw shaft 5 together, and these detected values are set to their respective set values. After approaching and matching, it will soon exceed the set value. The arithmetic and control unit 13 calculates both the detected values such as the thrust load and the torque which are inputted at regular intervals,
All of these detection values always exceed the detection value at the time of the previous calculation, and while the value does not exceed the set value, the control signal is issued from the calculation control device 13 to the drive device 9, and the weight ring 7 causes the compressed product discharge port 6 to be released. Controlled to be inserted into. If any of these detected values exceeds the detected value at the time of the previous calculation and exceeds the set value, the control signal is sent to the drive device 9 so that the weight ring 7 is pulled out from the squeezed material discharge port 6 by a certain distance. Is emitted. As a result, the opening ratio of the compressed product discharge port 6 is increased and the resistance when discharging the sludge is reduced.

When the squeezing pressure in the annular gap weakens, the amount of filtrate discharged from the outer cylinder 3 decreases, the water content of sludge in the annular gap increases, and when this begins to be discharged from the squeezed material discharge port 6, A control signal is issued from the arithmetic and control unit 13 to the drive unit 9 until the thrust load or the torque applied to the screw shaft 5 falls below the detected value at the time of the previous calculation and becomes equal to or less than the set value, so that the weight ring 7 is discharged. It is controlled so as to be pulled out from the exit 6 by a certain distance.

However, for example, when the amount of sludge charged into the press decreases suddenly or when the water content of the dehydrated pressed product increases due to the change in the properties of the input sludge, the outer cylinder 3, the screw blades 4, and Detecting the thrust load and torque applied to the screw shaft 5 because the amount of sludge injected into the annular gap formed by the screw shaft 5 decreases or the resistance at the time of discharging the sludge in the compressed product discharge port 6 decreases. The value is below these set values, and the arithmetic and control unit 1
A control signal from 3 is issued to the drive unit 9.
As a result, the drive device 9 is actuated, the weight ring 7 is inserted into the squeeze product discharge port 6, and the squeeze product discharge port 6 tries to operate to set the opening ratio of the squeezed product discharge port 6 to a smaller value. However, at this time, the operation of the arithmetic and control unit 1 by the operation of the lower limit value maintaining means 14.
The lower limit setting value is given priority over the instruction of 3, and the weight ring 7 is controlled so as not to be inserted below this value.

Regarding the operation of the lower limit value maintaining means 14,
This will be described with reference to the flowchart of FIG. When a squeeze operation command is issued (step 30), first the weight ring 7
Fully open (step 31). Then, the thrust load and torque are detected by the thrust meter 10 and the torque meter 11 (step 32). The detected thrust load and torque magnitude are compared with the set values set by the thrust setter 17 and the torque setter 16, respectively (step 3).
3). Here, the detected thrust load and torque will be collectively referred to as a load detection value (M ₁ ), and the set thrust load and torque will be collectively referred to as a load set value (M ₀ ). As a result of the comparison, when M ₁ > M ₀ , the first signal is input from the load comparison means 20 to the drive control means 23, so that the drive control means 23 issues a control signal to the drive device 9 to form the conical shape. The ring 7 is opened, that is, pulled out by a predetermined distance (step 34).

On the other hand, when M ₁ ≤M ₀ , the second signal is input from the load comparison means 20 to the position detector 19, and the position detector 19 detects the current position of the conical ring 7 (step 35). ). Next, the aperture ratio when the weight ring 7 is inserted into the compressed material discharge port 6 by a predetermined distance is calculated (step 3).
6). Here, the predetermined distance may be set arbitrarily, or may be appropriately calculated from the difference between M ₁ and M ₀ . Next, the calculated calculated aperture ratio (L ₁ ) and the lower limit aperture ratio (L ₁ ) set by the aperture ratio setting device 18
₀ ) is compared (step 37).

When L ₁ > L ₀ , aperture ratio comparing means 2
When the third signal is input from 2 to the drive control means 23 and the drive control means 23 issues a control signal to the drive device 9, the conical ring 7 is closed, that is, inserted by a predetermined distance (step 38). When L ₁ <L _0, a fourth signal is input from the aperture ratio comparing means 22 to the drive control means 23, and the drive control means 23 issues a control signal to the drive device 9 to close the conical ring 7. When it is inserted to the position of the lower limit aperture ratio, it stops at that position (step 39). When L ₁ = L ₀ , the weight ring 7 remains stopped. Then, unless there is a command signal to stop the operation of the compressor, when a predetermined time elapses from the time when the load set by the timer is detected, the process returns to step 32, and the processes from step 32 to step 39 are repeated.

As described above, in this screw press type squeezing machine, a control signal is issued from the drive control means 23 in the arithmetic and control unit 13 to the drive unit 9, and the weight ring 7 is actuated in response to the signal to squeeze. Although the opening ratio of the object discharge port 6 changes, since the lower limit value maintaining means 14 is provided,
The aperture ratio does not become smaller than the set value.

[0036]

The screw press type pressing method and screw press type pressing machine according to the present invention, which are configured as described above, have the following effects. That is, since the present invention is configured to control the drive of the weight ring by calculating the detected values of the thrust load and torque applied to the screw shaft, the detected thrust load and torque values are set to the set values. When it is larger, the weight ring is pulled out from the squeezed material discharge port by a predetermined distance and the opening ratio becomes larger. Insertion reduces the aperture ratio.

Therefore, since the thrust load and the torque are reduced when the amount of the sludge entering the sludge supply port becomes small, the opening ratio may not be extremely small in the conventional case. However, the present invention is provided with the position detector for detecting the position of the conical ring and the lower limit maintaining means for maintaining the opening ratio of the compressed material discharge port at a predetermined value or more. Does not become smaller than the set lower limit aperture ratio. Therefore, even if the amount of mud that is input to the sludge supply port is reduced, the opening ratio is maintained at a certain value or more, so that the co-rotation phenomenon of the squeezed product does not occur and stable operation can be continued. it can.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a screw press type compressor according to the present invention.

FIG. 2 is a vertical sectional side view showing an example of a conventional screw press type squeezing machine.

FIG. 3 is a vertical sectional side view showing another example of a conventional screw press type squeezing machine.

FIG. 4 is a vertical sectional side view showing still another example of a conventional screw press type squeezing machine.

5 is a block diagram of the screw press type squeezing machine shown in FIG. 1. FIG.

FIG. 6 is a flow chart for explaining the operation of the screw press type compressor shown in FIG.

[Explanation of symbols]

 1 Sludge Supply Port 3 Outer Cylinder 4 Screw Blade 5 Screw Shaft 6 Compressed Material Discharge Port 7 Cylinder Ring 9 Cylinder Ring Drive 10 Thrust Meter 11 Torque Meter 12 Screw Shaft Drive 13 Calculation Controller 14 Lower Limit Maintaining Means 18 Aperture ratio setting device 19 Position detector

Claims (2)

[Claims] 1. A mud put into an annular gap formed by an outer cylinder of a cylindrical filter medium having a sludge supply port and a compressed product discharge port, and a screw shaft having screw blades arranged in the outer cylinder. While discharging the shaped material while squeezing and dehydrating by the rotation of the screw shaft from the compressed material discharge port, the thrust load and torque applied to the screw shaft are detected, and the opening ratio of the compressed material discharge port based on the detected value. In the screw press type squeezing method, the opening ratio is controlled so as not to become smaller than a set lower limit opening ratio. 2. A screw shaft having screw blades is rotatably arranged in an outer cylinder of a cylindrical filter medium having a sludge supply port and a compressed product discharge port, and is formed by the outer cylinder, the screw shaft, and the screw blade. The volume of the annular gap is gradually reduced toward the compressed product discharge port, and a weight ring that reciprocates along the screw shaft by a driving device and adjusts the opening ratio of the compressed product discharge port is provided on the screw shaft. The thrust ring and the drive device for the weight ring are installed concentrically, and a thrust meter for detecting a thrust load applied to the screw shaft and a torque meter for detecting a torque are provided, and detection values detected by the thrust meter and the torque meter are calculated. In a screw press type compressor provided with an arithmetic and control unit for controlling, an opening ratio setting device for setting a lower limit opening ratio of the squeezed material discharge port, and the weight. A screw press-type squeezing machine comprising: a position detector for detecting the position of the ring-shaped ring; and a lower limit maintaining means for maintaining the opening ratio of the squeezed material discharge port at a predetermined value or more.