JPS58101714A - Method for supplying sludge to filter press - Google Patents

Abstract

PURPOSE:To drive a sludge supplying pump economically and to reduce the capacity of the pump, by providing a pressure tank of sludge to a sludge supplying pipe line on dehydrating the sludge by a filter press. CONSTITUTION:On dehydrating sludge in a sludge tank 2 by feeding it to a filter press 1 with the aid of a pump 3, a pressure tank 4 is arranged between the pump 3 and the filter press 1. Sludge in the tank 2 is fed into the pressure tank 4 once and when the sludge attains a prescribed quantity, it is sent by a pressure in the tank 4 to the filter press 1 to be dehydrated by opening an on- off valve 5. In this case, as the sludge is charged into the tank 4 by a fixed quantity equivalent to one dehydration cycle with the aid of a check valve 6 under a prescribed pressure, a pump 3 having a small capacity is available for a long time running and the operation rate is improved, and a large capacity of sludge can be treated by a pump having a small capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for supplying sludge to a pressure dehydrator such as a filter press.

Conventionally, in a filter press, sludge is supplied in the first
As shown in the figure, the pump 3 supplies sludge from the flocculated sludge tank 2 to the filtration chamber of the filter press 1 and filters it at the same time.At the start of sludge supply, the pressure on the discharge side of the pump 3 is almost equal to the piping resistance. However, if the filter chamber is filled with sludge and the filtration resistance increases, for example, 4 to 5 kg/
It becomes a CD.

In other words, as shown in Figure 3, the head rises over time and becomes constant when the filter chamber is filled with sludge, but
On the other hand, the force (shaft power) required to drive the pump 3 gradually decreases. If this lifting head and shaft power are plotted against the pump discharge amount, it will be as shown in Fig. 4. At the start of mud feeding, a large shaft power is required because the discharge amount is large.

Recently, as filter presses have become larger, the filtration area per unit has increased, but in order to supply sludge in the same short time as before, it is necessary to increase the pump discharge volume at the start of sludge supply. Increasingly, larger capacity pumps are required.

Furthermore, in the conventional supply method, since the ratio of the drive time of the pump 3 to one cycle processing time of the filter press is small, there is a drawback that the operating efficiency of the pump is low.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sludge supply method that eliminates the above-mentioned drawbacks and allows a small-capacity pump to operate efficiently.

That is, by providing a pressure tank in the sludge supply line of the filter press, the sludge supply pump can be operated economically, and the WWr of the pump can be reduced.

Hereinafter, an embodiment of the present invention will be described based on FIG. 2.

As shown in the figure, the sludge supply pump of the filter press is connected to a pressure tank 4 via an on-off valve 5, and a sludge pump 3 is connected to this pressure tank 4 via a check valve 6.

The sludge in the sludge tank 2 is stored in the pressure tank 4 by the pump 3 at a constant pressure within a range of, for example, 4 to 6 Kp/i. In other words, when the pressure inside the pressure tank 4 falls below a certain level, it is detected by a pressure switch, etc., and the detection signal drives the pump 3 to supply sludge into the pressure tank 4, and stops when the pressure reaches a certain level. Let them do it. This constant pressure may be the optimal value for this method as the mud supply pressure. For example, when the mud supply pressure is set to 4 to 5 kg/6I, the pressure is about 6 to 9/-.

Note that when the pump is in operation, the check valve 6 prevents sludge from flowing back from the pressure tank 4 to the pump 3.

The on-off valve 5 is opened only when sludge is supplied, and since the filter press is normally operated automatically, an automatically controllable solenoid valve is used. By opening this on-off valve 5,
The sludge in the pressure tank 4 has a pressure of 1. is fed into the filter press 1 by.

In addition, in the figure, 7 is a stirring device provided in the sludge tank 2.

Next, the operation of the above embodiment will be explained.

Now, with the pressure tank 4 maintained at a constant pressure, when the filter press 1 is closed and the on-off valve 5 is opened, the sludge in the pressure tank 4 is supplied into the filter press 1 by the pressure. Moving on to the next squeezing action.

In order to shorten this mud supply time, the capacity of the pressure tank 4 may be increased. On the other hand, the sludge pump J3 only needs to raise the pressure in the pressure tank 4 to a predetermined value after the sludge feeding process and before the next sludge feeding process. The capacity of the pump 3 is:
Compared to the conventional pump 3 that directly supplies mud, the slurry supply time can be reduced to the order of (time required for one cycle)/(time required for one cycle), and the shaft power can also be reduced to the same extent.

The following table shows a comparison between the conventional method and the method according to the present invention when feeding mud at a pressure of 4 to 51'g/-.

Furthermore, if the pressure tank 4 has a large capacity to reduce pressure fluctuations caused by mud supply, the pump head fluctuations of the pump 3 will also be reduced correspondingly to the pressure fluctuations, eliminating the problem of overload at the start of mud supply as in the past. Does not occur.

In addition, in the figure, two filter presses 1 are supplied with sludge through one pressure tank 44, but the number of filter presses 1 may be arbitrary, and the capacity of the pressure tank 4 can be adjusted according to the number. It may be set as appropriate.

Furthermore, as shown in FIG. 2, if a compressor 8 is connected to the upper part of the pressure tank 4 and compressed air is supplied appropriately, sludge can be supplied at a pressure higher than the pump head of the pump 3.

As described above, according to the sludge supply method of the present invention, the sludge in the pressure tank is supplied to the filter press using its pressure, so that the pressure in the pressure tank becomes constant during one cycle of the filter press. In this way, sludge can only be sent with a pump, and there is no need to directly pump a large volume of sludge in a short period of time as in the past, and a small-capacity pump can be used. By simply increasing the capacity of the pressure tank, mud can be supplied in a short time as before without increasing the capacity of the pump. Furthermore, since the pump can be driven during one cycle and there is time to drive the pump, there is an effect that the bomb can be operated economically.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the sludge supply piping of a conventional filter press, Figure 2 is a schematic diagram of the sludge supply piping of the filter press of the present invention, and Figures 3 and 4 are time, head, shaft power, and pump discharge time, respectively. It is a relationship diagram of quantity, lift, and shaft power. 1... Filter press, 2... Sludge tank, 3...
Pump, 4...Pressure tank, 5...Opening/closing valve Patent applicant: Kubota Iron Works Co., Ltd. Agent: Sickle 1
) Sentence 2

Claims (1)

[Claims] A pressure tank is connected to the sludge supply pipe of the filter press via an on-off valve, sludge is sent to this pressure tank by a pump to store sludge at a constant pressure, and the sludge in the pressure tank is removed by opening the on-off valve. A sludge supply method consisting of supplying sludge to a filter press under its pressure.