JP2923935B2 - Operation control device for screw press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a screw press used for dewatering sewage sludge and the like.

[0002]

2. Description of the Related Art Conventionally, a screw press in which an outer cylinder having a screen stretched around its periphery is fixed to a machine frame, and a feed shaft is supported in the outer cylinder is well known. It is also well known that the outer cylinder is supported so as to be rotatable, and when the peripheral screen is clogged, the outer cylinder is rotated to perform cleaning. JP-B-54-12774 and JP-B-3-78123 are examples of the latter.

[0003]

In the case where the outer cylinder does not rotate, the operation must be stopped to clean the screen when the screen is clogged, and in the case where the outer cylinder rotates, the cleaning is simply easy. It is not possible to always operate to obtain a cake having a desired moisture. That is, in the case of a stock solution having a good dewatering property, the dewatering operation can be efficiently performed regardless of the rotation of the outer cylinder. In some cases, the squeezing unit becomes full of cake and becomes inoperable. In such a case, if the outer cylinder does not rotate, cleaning the screen is troublesome. Further, even when the outer cylinder rotates, if the cake is filled in the outer cylinder, the outer cylinder and the feed shaft rotate together, and the cake is not conveyed and the dewatering operation cannot be performed.

[0004]

SUMMARY OF THE INVENTION The present invention can solve the above-mentioned conventional problems, and the gist of the present invention is to wind a screw blade around a periphery in a screen outer cylinder. In a screw press that rotatably supports the feed shaft, the screen outer cylinder is not rotatable in the feed rotation direction of the feed shaft, and is supported on the machine frame rotatably in a direction opposite to the rotation direction of the feed shaft, A stopper for preventing the rotation of the screen cylinder supported on the machine frame is provided with a device for detecting the rotation torque of the screen cylinder, and the detection device and the operation control device of the screw press are interlocked, and the detected screen is detected. Rotating torque of outer cylinder and dehydrating case
Calculate the rotation torque of the feed shaft from the friction coefficient of the
When an abnormal operation is detected, the feed shaft is
Clean the outer cylinder or operate the screw press.
The rotation is stopped and the supply of the undiluted solution is adjusted .

[0005]

The apparatus according to the present invention is constructed as described above. During normal operation (when a predetermined amount of cake of predetermined moisture is obtained), the screen outer cylinder is fixed by a stopper. The supplied stock solution is dewatered without rotating. During this normal operation, the supplied stock solution applies torque to the stopper due to the pressing force of the feed blade due to the rotation of the feed shaft and the friction between the stock tube solidification due to the solidification of the stock solution accompanying dehydration by the screen tube. Dehydrated while transmitting. That is, the rotational torque RT of the screen outer cylinder,
Assuming that the rotation torque ST of the feed shaft and the friction coefficient of the dewatered cake are μ, RT = μ × ST. If there is nothing in the space inside the screen outer cylinder without supplying the undiluted solution, μ = 0, and the stopper Does not transmit torque. Then, when a foreign substance is caught between the screen outer cylinder and the feed shaft and the screen outer cylinder and the feed shaft are integrated, μ = 1, and during the spin-drying operation, the friction coefficient μ is 0 <μ <1. Yes,
Therefore, if the torque of the stopper of the screen outer cylinder is detected during the operation, it can be known whether or not the dehydration operation of a certain undiluted solution is normally performed. For example, when the torque of the screen outer cylinder is greatly reduced from a predetermined value, the undiluted solution in the screen outer cylinder is perceived as being in a fluid state without being caked, and it can be understood that dehydration has not been performed. It is possible to take measures such as increasing and concentrating the feed stock solution,
In addition, when the torque of the screen outer cylinder is rapidly increased, it is possible to know that dewatering is impossible due to biting of foreign matter or filling of the dewatering cake. It is possible to take measures such as cleaning the screen outer cylinder. Hereinafter, the present invention will be specifically described based on examples.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes a screen outer cylinder having a screen stretched around its periphery, 2 denotes a feed shaft supported inside the screen outer cylinder 1, and 2a denotes a screw wound around its periphery. It is a sending blade. Although not shown, the feed shaft 2 is connected at one end (left side in the figure) to a driving machine so as to rotate, and feeds the undiluted solution supplied from the hopper 3 into the screen outer cylinder 1 with its feed blade. The cake is conveyed by 2a and dewatered, and is taken out as cake from the outlet 4 at the other end of the screen outer cylinder 1.

On the other hand, the screen outer cylinder 1 is rotatably supported at both ends by a machine frame 5, and as shown in FIG. 2, the screen outer cylinder 1 projects outward from the screen frame 1a. The lever 6 is engaged with a stopper 5a fixed to the machine frame 5, so that the lever 6 cannot rotate in the rotation direction of the feed shaft 2 (indicated by an arrow A), and in the opposite direction (indicated by an arrow). (Rotation direction b). The stopper 5a is provided with a device for detecting the pressing force from the lever 6, that is, the rotational torque of the screen outer cylinder 1, and this device is connected to the operation control device of the screw press. In the drawings, reference numeral 7 denotes a roller 8 for supporting the screen outer cylinder 1, and a pusher for adjusting the opening of an outlet.

In the screw press constructed as described above, the undiluted solution supplied from the hopper 3 into the screen outer cylinder 1 is rotated by the feed shaft 2 so as to be pressurized by the feed blades 2a and to the left in the figure. , While being dehydrated by the screen outer cylinder 1, and solids are taken out of the machine from the outlet 4 as cake.

During the above-described undiluted solution processing operation, for example, a portion where the inner chamber of the screen outer cylinder 1 is reduced is filled with undiluted solution (cake), or foreign matter in the undiluted solution is transferred to the feed shaft 2 and the screen. When the screen outer cylinder 1 is engaged with the outer cylinder 1, the screen outer cylinder 1 cannot be rotated in the same direction as the feed shaft 2, and thus becomes integral with the feed shaft 2. Therefore, the stopper 5a receives the rotation torque of the feed shaft, that is, the rotation torque of the screen outer cylinder 1.

In such a case, in the apparatus according to the present invention, the rotation torque of the feed shaft 2 is directly detected as the rotation torque of the screen outer cylinder 1 and transmitted to the operation control device. Can stop the operation and prevent the device from being damaged. Also,
It is also possible to clean the screen outer cylinder 1 to release the excessive torque caused by the clogging. (See Fig. 3)

Further, even if the feed shaft 1 is driven after the operation is started, if the rotation torque detected by the stopper 5a is smaller than a predetermined value, it is determined that there is no unprocessed liquid in the screen outer cylinder 1. It has a low concentration and is in a fluid state, and at this time, no filtration operation can be performed. Even in such a case, in the device according to the present invention, the abnormality in the screen outer cylinder 1 is detected by the stopper 5a and transmitted to the operation control device to stop the operation urgently or to adjust the supply of the undiluted solution. You can also

FIG. 3 is a block diagram showing an example of the operation of the apparatus according to the present invention, and shows control contents corresponding to a case where the load applied to the screen outer cylinder 1 is abnormal (excessive or excessive). When a load occurs, the screen cylinder 1 is cleaned, the rotation torque generated in the screen cylinder 1 is returned to normal, and the operation is continued (B series in the drawing), and the rotation torque of the screen cylinder 1 is the highest setting. The state corresponding to an abnormal load (torque) is indicated by stopping the operation when the value exceeds the value (A series in the figure).

When the torque of the screen cylinder 1 becomes excessive, the power for rotating the screen cylinder for cleaning is such that the screen cylinder 1 is rotatable in the direction opposite to the feed shaft 2. When the feed shaft 2 is reversed, the feed shaft 2 is rotated integrally with the feed shaft 2 by the foreign matter caught in the screen outer cylinder 1 or the filled stock solution (cake). The screen can be washed uniformly.

[0014]

As described above, in the conventional screw press,
It was difficult to measure the rotational torque of the feed shaft
However, in the present invention, the rotation of the screen outer cylinder is performed.
By detecting the rolling torque, it is possible to detect the feed shaft load abnormality.
Therefore, this detection information is transmitted to the operation control device of the screw press, and based on the detection information, it is possible to adjust the supply amount of the undiluted solution or take an emergency action such as an emergency stop of the machine. nature, by setting the maximum minimum limit value of the rotational torque generated in the feed shaft or screen outer tube on the basis of the nature, post is obtained by allowing the automatic operation continuous.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional side view of a screw press according to the present invention.

FIG. 2 is a schematic cross-sectional view of a main part of the same.

FIG. 3 is a block diagram showing the operation of the operation control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Screen cylinder 2 Feed shaft 2a Feed blade 5 Machine frame 5a Stopper RT Rotation torque ST of screen cylinder Rotation torque μ of feed shaft μ Coefficient of friction of dewatered cake

Claims (1)

(57) [Claims] In a screw press in which a feed shaft (2) having a feed blade (2a) wound around a periphery thereof is rotatably supported in a screen outer cylinder (1), the screen outer cylinder (1) is moved in the feed rotation direction of the feed shaft (2). While being unrotatably supported on the machine frame 5 so as to be rotatable in the direction opposite to the feed rotation direction of the feed shaft 2,
A stopper 5a for preventing rotation of the screen cylinder 1 provided on the machine frame 5 is provided with a device for detecting the rotation torque of the screen cylinder 1, and this detection device is linked with the operation control device of the screw press. Out of screen detected
From the rotational torque RT of the cylinder 1 and the friction coefficient μ of the dewatered cake
The rotation torque ST of the feed shaft 2 is calculated, and the abnormality of the dehydration operation is determined.
When it is detected, the feed shaft 2 is reversed and the screen
Clean or stop screw press
An operation control device for a screw press, wherein the supply of the undiluted solution is adjusted .