JP3135411B2 - Concentrated sludge transfer system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concentrated sludge transfer system, and more particularly to a concentrated sludge transfer system suitable for supplying a constant amount of concentrated sludge to a sludge drying device.

[0002]

2. Description of the Related Art As a concentrated sludge transfer device, for example, a device as shown in FIGS. 5 and 6 is known. The concentrated sludge transfer device shown in FIG. 5 includes a concentrated sludge storage hopper 30, a concentrated transfer pump 31, and a plurality of sludge drying devices, that is, sludge drying devices 32 and 33. Then, the concentrated sludge in the concentrated sludge storage hopper 30 is pumped by the concentrated sludge transfer pump 31 and sent to the concentrated sludge transfer pipe 34 provided between the concentrated sludge transfer pump 31 and the sludge drying devices 32, 33. The concentrated sludge is quantitatively distributed and supplied to the sludge drying devices 32 and 33 through the branch pipe 35.

In the apparatus shown in FIG. 6, two concentrated sludge transfer pumps 36 and 37 are provided in a concentrated sludge storage hopper 30, and two sludge drying devices 32 and 33 are provided. Sludge transfer pipe 38,3 from
The concentrated sludge is supplied to the respective sludge drying devices 32 and 33 via the feed line 9 in a constant amount.

However, in the concentrated sludge transfer device shown in FIG. 5, when the concentration of the concentrated sludge changes from a high concentration to a low concentration, the concentrated sludge cannot be quantitatively distributed to the sludge drying devices 32 and 33, and a predetermined amount of the sludge cannot be distributed. However, there was a disadvantage that the dried sludge could not be obtained as expected.

[0005] That is, if the sludge concentration is high, the state becomes close to a solid, and the solid component is pushed out to the two sludge drying devices 32 and 33 at the branch pipe portion by the action of pushing out. Therefore, the pushing action is weakened, and the surface resistance of the inner surface of the pipe has a large effect,
A phenomenon occurs in which the water is not distributed well in the branch pipe portion and flows unilaterally to a surface having a lower surface resistance. When such a phenomenon occurs, among the plurality of sludge drying devices 32 and 33,
One is overloaded and cannot be dried sufficiently, and the other is in a quiescent state.

In the apparatus shown in FIG. 6, between the concentrated sludge transfer pumps 36, 37 and the sludge drying devices 32, 33, concentrated sludge transfer pipes 38, 39 having a large diameter must be constructed in consideration of pressure loss. However, this is usually relatively distant from the arrangement of the treatment plant, and the large-diameter concentrated sludge transfer pipes 38 and 39 have to be arranged with a considerable length, which has the disadvantage of increasing the cost. .

[0007]

As described above, in the case of the branch system shown in FIG. 5, it is difficult to perform quantitative distribution when the sludge concentration is reduced, and in the case of the individual transfer system shown in FIG. 6, facility costs are increased. There was a problem of doing.

It is an object of the present invention to provide a concentrated sludge transfer system capable of stably requesting a fixed amount of concentrated sludge from a plurality of sludge drying apparatuses even when the concentration of the concentrated sludge changes.

[0009]

The concentrated sludge transfer system according to the present invention is a concentrated sludge transfer system for transferring concentrated sludge in a hopper to a plurality of sludge drying devices via a concentrated sludge transfer pump. A header pipe is provided between a pump and the sludge drying device, and a concentrated sludge supply pump is provided on the discharge side of the header pipe to supply a constant amount of concentrated sludge to the plurality of sludge drying devices. A control device is provided for controlling the rotation speed of the concentrated sludge transfer pump so that the pressure is within the range.

[0010]

According to the present invention, the concentrated sludge in the concentrated sludge storage hopper is pumped by the concentrated sludge transfer pump, and is sent to the concentrated sludge header pipe provided near the sludge drying device via the sludge transfer pipe.

Since the sludge pressure in the concentrated sludge header pipe is controlled so as to be within a predetermined range, each concentrated sludge supply pump provided on the discharge side of the concentrated sludge header pipe connects each sludge transfer pipe. The concentrated sludge is supplied and distributed to each sludge drying unit via the fixed amount.

The sludge pressure in the concentrated sludge header pipe is as follows:
Based on the measurement result of the sludge pressure measuring device, the control device controls the number of rotations of the concentrated sludge transfer pump, thereby controlling the sludge to be within a predetermined range.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a concentrated sludge transfer system according to the present invention will be described with reference to FIGS. The concentrated sludge stored in the concentrated sludge storage hopper (hereinafter referred to as hopper) 1 is
It is pumped by a concentrated sludge transfer pump (hereinafter, referred to as a pump) 2, and is guided to a concentrated sludge header pipe (hereinafter, referred to as a header pipe) 5 via a concentrated sludge transfer pipe 6.

Since the pressure in the header pipe 5 is controlled so as to be within a predetermined range as described later, the concentrated sludge in the header pipe 5 is concentrated sludge provided on the discharge side of the header pipe 5. Supply pump (hereinafter referred to as supply pump) 7, 8
Is supplied to the sludge drying devices 3 and 4 via the respective concentrated sludge moving pipes 9 and 10, and the concentrated sludge is dried by the sludge drying devices 3 and 4.

The pressure in the head pipe 5 is measured by a sludge pressure measuring device 11, and the measured value is input to a control device 13. Then, the control device 13 performs a predetermined calculation based on the obtained measurement value, and provides the rotation speed data of the pump 2 to the rotation speed control device 12 of the pump 2,
By controlling the number of rotations, the pressure in the header tube 5 is controlled.

The control device 12 performs PI control so that the pressure in the header pipe 5 falls within a predetermined range. In the concentrated sludge transfer system configured in this way,
The concentrated sludge stored in the hopper 1 is quantitatively supplied to the sludge drying devices 3 and 4 by the pump 2, but when the two sludge drying devices 3 and 4 have the same processing capacity, the sludge drying devices 3 and 4 are used. It is necessary to distribute the supply of concentrated sludge to the plant evenly. In order for the sludge drying devices 3 and 4 to have good drying performance, a constant amount of sludge is always supplied.
That is, the sludge needs to be supplied in a fixed amount.

Therefore, on the discharge side of the concentrated sludge transfer pipe 2,
In addition, it is necessary to provide a header pipe 5 near the sludge drying devices 3 and 4 and to maintain the pressure in the header pipe 5 within a predetermined range. By means of 8, sludge can be supplied to each of the sludge drying devices 3 and 4 quantitatively. That is, the inside of the header tube 5 is
For example, when the pressure becomes negative, it becomes difficult to perform the quantitative supply by the supply pumps 7 and 8 as well as the equal distribution by the supply pumps 7 and 8. If the pressure in the header tube 5 rises abnormally, stress on the header tube 5 and the supply pumps 7 and 8 increases, making it difficult to perform a predetermined function and damaging equipment.

Then, the pressure of the header tube 5 is, for example,
The target pressure is set so as to be in a range of 0.5 to 2.0 kg / cm ² . In order to keep the pressure in the header pipe 5 within a predetermined range, the control device 13 uses the sludge pressure measuring device 1
Based on the pressure signal of the header tube 5 measured by 1, a rotation speed set value is given to the rotation speed control device 12 so that the pump 2 has a predetermined rotation speed.

Next, the control algorithm of the present invention will be described with reference to the flowchart of FIG. 2 and the explanatory diagram of FIG. Note that T in FIG. 3 indicates a control start timing of the present system, and t1 to t5 indicate data sampling timings.

In the case of pressure control of the header pipe 5 (step S
1) The control device 13 determines whether or not the sludge pressure in the header pipe 5 is within the above-described target range based on the measurement result of the sludge pressure measurement device 11 (step S2). At this time, the control device 13 does nothing if the pressure is within the target range (route R1), but if the pressure is outside the target range, the control device 13 checks whether or not the time is the control time T in FIG. Step S3). If the time is not the control time T, nothing is performed (route R2). If the time is within the control time T, whether any of the data sample times t1, t2, t3, t4, and t5 is reached. Is checked (step S4). If the time is not the data sampling time (route R3), nothing is performed, but if the data sampling time is the time t1, t2, t3, t4, t5, the measurement data of the sludge pressure measuring device 11 and the control data of the control device 13 are obtained. Based on the above, a predetermined PI calculation is performed, and the rotation speed as the calculation result is given to the rotation speed control device 12 of the pump 2 to control the discharge pressure of the pump 2 (step S5). And
After collecting the data for the predetermined number of times and performing the calculation and control for the predetermined number of times, the control required for this control cycle is terminated (step S6).

With this control, the pressure in the header pipe 5 is maintained within a predetermined range, so that the concentrated sludge is evenly distributed to the sludge drying devices 3 and 4 by the supply pumps 7 and 8, respectively. Since the fixed amount supply is performed, the sludge drying devices 3 and 4 can be efficiently operated in a good state without causing overload or operation suspension.

Further, since the concentrated sludge transfer pipe 6 up to the vicinity of the sludge drying devices 3 and 4 can be shared, the header pipe 5 and the supply pumps 7 and 8 are added. Equipment costs can be reduced as compared with the conventional example.

FIG. 4 is a view showing another embodiment of the present invention. In FIG. 4, in addition to the supply pumps 7 and 8, supply pumps 16 and 17 are further provided on the discharge side of the header pipe 5, and the concentrated sludge is provided. The respective sludge dryers 14 and 1 are connected via transfer pipes 17 and 18.
5, and the control method is the same as that described above. In this case, the effect of reducing the equipment cost with respect to the conventional example in FIG.
In this embodiment, an equal amount of concentrated sludge is supplied to each sludge drying device, but it is also possible to supply a predetermined amount of concentrated sludge to sludge drying devices having different treatment amounts.

[0024]

Since the concentrated sludge transfer system of the present invention is constructed as described above, even if the sludge concentration of the concentrated sludge changes during operation, the sludge pressure in the header pipe is controlled within a predetermined range. Therefore, it is possible to maintain a constant supply of the supply pump, so that it is possible to supply a stable concentrated sludge to each sludge drying device, and it is possible to obtain a concentrated sludge having a predetermined water content. Therefore, it is possible to avoid such a problem that each sludge drying device stops due to insufficient supply of sludge.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a concentrated sludge transfer system of the present invention.

FIG. 2 is a flowchart illustrating a control algorithm according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a state of the control.

FIG. 4 is a configuration diagram showing another embodiment of the present invention.

FIG. 5 is a diagram showing a conventional example.

FIG. 6 is a diagram showing another conventional example.

[Explanation of symbols]

 1 ... concentrated sludge storage hopper (hopper) 2 ... concentrated sludge transfer pump (pump) 3, 4 ... sludge drying device 5 ... concentrated sludge header pipe (header pipe) 6, 9, 10 ... ... concentrated sludge transfer pipe 7, 8 ... concentrated sludge supply pump (supply pump) 11 ... sludge pressure measuring device 12 ... rotational speed control device 13 ... control device.

Claims (1)

(57) [Claims] 1. A concentrated sludge transfer system for feeding concentrated sludge in a hopper to a plurality of sludge drying devices via a concentrated sludge transfer pump, wherein a header pipe is provided between the concentrated sludge transfer pump and the sludge drying device. On the discharge side of the header pipe, a concentrated sludge supply pump for supplying a fixed amount of concentrated sludge to each of the plurality of sludge drying devices is provided.Furthermore, the number of rotations of the concentrated sludge transfer pump is adjusted so that the pressure in the header pipe is within a set range. A concentrated sludge transfer system, comprising a control device for controlling the concentration of sludge.