JPS5927207B2 - How to operate a screw type sand raking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a screw-type sand settling device that constitutes a treatment facility for municipal sewage and the like.

FIG. 1 shows an example of a conventional screw-type sand raking device using an electric motor.

In FIG. 1, the screw-type sand raking device includes a screw 3, an electric motor 4, and an electric motor 40, which constitute a screw conveyor installed at the bottom 2 of a sand settling basin 1. Rotational force is transmitted to the screw 3 via a bevel gear box 6. It is composed of a rotating vertical shaft 5 that rotates.

In the screw-type sand raking device configured as described above, when sewage flows in from the direction of arrow A and sand etc. in the sewage accumulates on the pond bottom 2, the electric motor 4 installed on the floor 1a is driven and the vertical shaft 5 is rotated, and the screw 3 is rotated via the bevel gear box 6.

When the screw 3 is driven, the sand in the pond bottom 2 is scraped up into the sand pit 1 and sent from the sand pit 7 to the sand pump 8.
It is discharged to the outside.

In actual sewage treatment plants, a timer is used to set the time (usually multiple times) during the day when the screw is automatically operated, and when this time comes, the screw is operated for a certain period of time to scrape out the sediment. I was approaching it.

However, with the above operating method, the settling basin 1
Even if more than a certain amount of sediment is not deposited on the pond bottom 2,
When the time came to operate the screw, the screw was operated for a certain period of time.

As a result, energy sources such as electric power may be wasted, and the equipment wears out more quickly, resulting in more frequent failures.

The present invention aims to improve the above-mentioned conventional drawbacks.

The present invention focuses on the fact that the rotational load on the screw changes depending on the amount of accumulated sand, and when the rotational load at the beginning of the screw operation is lower than a preset value, the screw is immediately started. This is a method of operating a screw-type sand raking device that suspends the operation until the next operation period.

The present invention will be explained below based on examples.

2 and 3 are diagrams showing an outline of an apparatus for carrying out the present invention, in which FIG. 2 shows a case in which the screw is driven by an electric motor, and FIG. 3 shows a case in which the screw is driven by a hydraulic motor.

FIG. 2 shows that the rotational force of an electric motor 90 is transmitted to the rotating vertical shaft 10,
Furthermore, the configuration is such that the signal is transmitted to the screw 12 via the gear box 11.

A current switch 13 is connected to the power source of the electric motor 9 as a means for detecting the rotational load of the screw 120.

When the current switch 13 operates the screw 12,
When the rotational load on the screw 12 is lower than a predetermined value (when the amount of settled sand is small), the rotation of the screw 120 is stopped.

FIG. 3 shows a configuration in which the screw 12 is rotated by a hydraulic motor 15 driven by hydraulic pressure supplied from a hydraulic unit 14.

Then, a pressure switch 16 is connected to a pipe connecting the hydraulic unit 14 and the hydraulic motor 15.

The pressure switch 16 functions to stop the rotation of the screw 120 when the screw 120 rotation load is lower than a predetermined value (when the amount of sediment is small) when the screw 12 is operated.

FIG. 4 is a diagram showing the operating method of the present invention.

In the figure, the horizontal axis indicates the time T1 during the day when the screw 12 is operated. T2. T3. . . . , and the vertical axis indicates the rotational load when the screw 12 is rotated.

First, at time T1 when the screw 12 is operated, when the screw 12 is rotated, the rotational load is a value P1 larger than a preset value P.

As a result, it is determined that a sufficient amount of sediment has been deposited at the bottom of the settling basin, so the operation of the screw 12 is continued for the time t1 until the rotational load decreases to P.

At the next time T2 when the screw 12 is operated, the screw 12 is operated for a period of time Δ, and since the rotational load is a value P2 lower than the preset value P, the operation of the screw 12 is immediately stopped.

Thereafter, the screw 12 is operated in the same manner at the timing T3.
At T4, the rotational load of the screws 12 is greater than the preset value P3, P4, so each screw 12 is
3. Operate for 14 hours to scrape up the sand.

The present invention described above has the following effects.

1) During the screw operation period, if there is little sedimentation at the bottom of the pond, the screw operation can be immediately stopped.

This prevents unnecessary operation of the screw, which helps to save power, etc.

2) Since wasteful operation of the equipment is eliminated, wear of screw blades, bearings, and other parts that wear out is reduced, which extends the life of the equipment.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a screw type sand raking device, Figs. 2 and 3 are schematic diagrams showing an example of the device for carrying out the present invention, and Fig. 4 shows an operating method of the present invention. It is a diagram. 9: Electric motor, 12: Screw, 13: Current switch,
14: Hydraulic unit, 15: Hydraulic motor, 16: Hydraulic switch.

Claims (1)

[Claims] 1. In a method of operating a screw-type sand raking device in which a screw conveyor is installed at the bottom of a sand settling basin, the operating timing of the screw is set in advance, and the rotational load of the screw at the initial stage of operation in the operating timing is set. A method for operating a screw-type sand settling device, characterized in that when the value is lower than a predetermined value, operation of the screw at that period is stopped. 2. The screw type grit scraper according to claim 1, characterized in that when the rotational load on the screw is higher than a preset value, the screw is rotated until the rotational load becomes lower than the preset value. How to operate the equipment.