JPH07108362B2 - High pressure filter press stock solution injection method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stock solution injection method for a high-pressure filter press for performing solid-liquid separation of various stock solutions of high-concentration sludge such as construction, sewage, and food.

[Prior Art] A filter press has a structure in which a plurality of filter plates having an uneven surface can be opened and closed, and a filter cloth is stretched so as to wrap the filter plates. The filter plate is closed between the filter cloths. The stock solution is pressed into the formed filter chamber with a pump, the filtrate is discharged to the surface of the filter plate through the filter cloth, and the solid content is collected in the filter cloth to form a cake in the filter chamber. When the cake is completely filled in, the supply of the stock solution is stopped, and the filter plate is sequentially opened from one side to discharge the cake.

In this filter press, the water content of the cake is reduced in order to reduce the secondary treatment of the dehydrated cake, and due to the installation space, the stock solution filtration rate is increased to reduce the size of the device. It has become a problem to solve this problem. As a method of solving this problem, the rubber ball of the high-pressure feeding device is described in "Itto Juken" September 1987 issue P35-38 edited by Tokyo International Trade and Industry Bureau. A high-pressure filter press that drives the diaphragm hydraulically to press the high-concentration stock solution into the filter chamber at high pressure for solid-liquid separation has been proposed and known, and the filtration pressure is 7 to 15 kg of that of a conventional filter press.
The water content of the dehydrated cake is low because filtration and dehydration are performed with a high-pressure constant discharge pump of about 40 kg / cm ² for / cm ² .
Another feature is that the stock solution press-in time can be shortened from 8 minutes to 10 minutes as compared with the conventional filter press of 30 minutes to 3 hours, which is a high solution filtration rate.

[Problems to be solved by the invention] Usually, in this type of high-pressure filter press, the total injection amount of the stock solution decreases in inverse proportion to the solid concentration in the stock solution. The ratio of the chamber filling volume (filter chamber volume) increases. As a result, there has been a problem that the stock solution treatment capacity per stock solution press-in time is reduced, the apparatus has a large capacity when a certain amount of stock solution is processed, the equipment cost is increased, and the installation space is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a stock solution press-fitting method for a high pressure filter press, which aims at improving the stock solution filtration rate in order to achieve the above-mentioned problems of compactness and cost reduction of the high pressure filter press.

[Means for Solving the Problems] The present invention has the following structure in order to achieve the above object. That is, (1) in a filter press in which a high-concentration stock solution is pressed under high pressure into a filter chamber formed by a filter cloth and a filter plate to separate a cake and a filtrate, the start of the filtration is set as a reference time, and the filtration after the reference time is performed. While the process is in progress (filtration time θ ₂ ), the high-concentration stock solution is supplied at the optimum stock solution injection speed q ₁ , and while the stock solution is being supplied to the filter chamber before the reference time (filter chamber charging time θ ₁ ). Is a high-pressure filter press stock solution injection method characterized in that the high-concentration stock solution is supplied at a filtration chamber filling solution stock solution injection rate q ₂ which is larger than q ₁ .

[Operation] Since the present invention is configured as described above, pressurization of the undiluted solution at the time of filling the filter chamber, which is unrelated to pressure filtration, is performed at a large speed q ₂ in a short time, and after the filtration is started, Since the stock solution is injected at the optimum stock solution injection speed q ₁ that is smaller than the stock solution injection speed during liquid injection,
The average filtration rate of the stock solution of the filter press, that is, the throughput of the stock solution is increased.

[Examples] Hereinafter, the features of the present invention will be specifically described with reference to the drawings of the examples.

FIG. 1 is a constitutional view of a high-pressure filter press used to carry out the method for press-fitting a stock solution of the present invention.

The high-pressure pumping device 1 is provided with a diaphragm 2 having flexibility and elasticity therein, and the convex side of the diaphragm 2 is used as a stock solution pressure feed chamber 3, and a stock solution suction pipe 4 and a check valve 5a are provided in the stock solution pressure feed chamber 3. At the same time, the stock solution pressure feeding pipe 6 is connected to the filter press 7 via the check valve 5b.

On the other hand, the concave side of the diaphragm 2 is used as a hydraulic fluid chamber 8, and a hydraulically driven cylinder is provided between the hydraulic fluid chamber 8 and the hydraulic unit 9, for example.
A hydraulic fluid metering device 12 is provided so that the hydraulic fluid metering cylinder 10 and the hydraulic fluid metering cylinder 11 can be linked together, and the metering cylinder 11 and the hydraulic fluid chamber 8 are connected by a hydraulic fluid pipe 13.

The hydraulic unit 9 is composed of an oil tank 14, a variable discharge hydraulic pump 15, a solenoid valve 16 and the like. The hydraulic unit 9 and the drive cylinder 10 are connected by a hydraulic pipe 17 to form an oil circulation circuit. .

Because of this structure, the solenoid valve of the hydraulic unit 9
By switching between 16, the drive cylinder 10 and the hydraulic fluid metering cylinder 11 reciprocate integrally, and the diaphragm 2 of the high-pressure feeding device 1 expands and contracts to suck the stock solution into the stock solution pressure-feeding chamber 3 and It is press-fitted into the filter press 7 at high pressure to perform filtration dehydration.

Since the variable discharge hydraulic pump 15 has a high pressure and is required to rapidly change the discharge amount, a valve plate-swash plate type axial plunger pump or the like is usually used.
Pressure transmitter 18
The signal is used to control the discharge amount.

FIG. 2 is a view showing the concept of a stock solution press-fitting method for a high-pressure filter press according to the present invention, and FIG. 3 is a view showing the concept of a stock solution press-fitting method for a conventional high-pressure filter press.

As shown in FIG. 2, in the stock solution injection method of the present invention, the stock solution injection time θ is divided into a filter chamber filling time θ ₁ and a filtration time θ ₂ .
Filter chamber Takashieki time theta ₁ of filter chamber Takashieki stock pressed rate q ₂ large cities than the optimal stock pressed rate q ₁ of filtration time theta _2, the filter chamber Takashieki completion of the stock solution filter chamber pressure or undiluted accumulated flow etc. It detects and sharply reduces the stock solution injection speed to the optimum stock solution injection speed q ₁ to shorten the stock solution injection time.

Fig. 4 and Table 1 show the results of a filtration test comparing the present invention with a conventional high-pressure filter press stock solution injection method, and show that civil muddy water with a slurry concentration of 30% was collected in the filter chamber (thickness 15 mm x diameter 12
A filtration test was carried out using a filter press of 00 mm × 65 chambers) at a filtration setting pressure P ₁ of 40 kg / cm ² .

In the figure, the dotted lines a, b, and c are the results of the filtration test by the conventional stock solution press-fitting method, and the stock solution press-fit rate a is 100 / m ² · h, b is 150.
/ m ² · h, c is 200 / m ² · h and the injection time of the stock solution is 15
It was constant in minutes. However, the unit of the stock solution injection speed is the stock solution amount, m ² is the filtration area, and h is the stock solution injection time. In addition,
The injection time of the stock solution is as long as 15 minutes in the embodiment of the present invention, compared with 8 to 10 minutes in the cited document of the prior art, which is due to the difference in the properties of the stock solution for treatment.

As can be seen from the figure, in this type of filter press, there is an optimum stock solution injection speed that maximizes the stock solution injection amount V at a predetermined stock solution injection time θ, and under this test condition, the optimum stock solution injection rate is b. It was 150 / m ² · h.

That is, since the stock solution injection amount V has the maximum value at the optimum stock solution injection speed, the stock solution average filtration rate is maximum and the cake water content is the minimum. If the stock solution injection rate is smaller than this value, for example, the case of a occurs. , Filtration pressure P is set pressure P ₁
If the stock solution pressure-injection rate is higher than this value, for example, in the case of c, a hard cake layer is formed on the surface of the filter cloth under pressure and the filtration rate is increased. Decrease, resulting in an increase in cake water content.

Further, the solid line d in the figure is the result of the filtration test by the stock solution press-fitting method of the present invention, and the stock chamber filling liquid has a stock solution press-fit speed q ₂ of 450 / m ² ·
h × 1 minute, the optimum stock solution injection speed q ₁ during filtration is the same as before
Filtration and dehydration were performed at 150 / m ² · h × 12 minutes, and when the stock solution injection time θ was 13 minutes, the same level of stock solution injection quantity V as the conventional one was obtained.

As can be seen from the comparison of the filtration test results in Table 1, in the case where the cake water content is the same, the undiluted solution injecting method of the present invention has an average undiluted solution filtration rate of about 10% in the case where the water content of the cake is the same. It increased by 16% (d / b).

[Effects of the Invention] As described above, the stock solution press-in method for the high-pressure filter press of the present invention performs stock solution press-fitting at the time of filling the filter chamber, which is unrelated to pressure filtration, at a high speed in a short time, and after starting filtration. Since the time is to press the stock solution at the optimum stock solution press-in speed q ₁ which is smaller than the filter room filling stock solution press-fitting speed q ₂ at the time of filling the filter room, the apparatus can be made compact by increasing the stock solution average filtration rate,
The equipment cost per stock solution to be processed is reduced, and the installation space is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a high-pressure filter press used for carrying out the stock solution press-fitting method of the present invention, FIG. 2 is a view of the stock solution press-fitting method of the high-pressure filter press of the present invention, and FIG. 3 is a conventional high-pressure filter press. FIG. 4 is a conceptual diagram showing the stock solution press-in method of FIG. 4, and FIG. 4 is a view of the filtration test results showing a comparison between the present invention and the conventional stock solution press-fitting method. 1: High-pressure feeding device, 2: Diaphragm, 3: Undiluted liquid pressure feeding chamber, 4: Undiluted liquid suction pipe, 5: Check valve, 6: Undiluted liquid pressure feeding pipe, 7: Filter press, 8:
Hydraulic fluid chamber, 9: hydraulic unit, 10: drive cylinder, 11: metering cylinder, 12: metering device, 13: hydraulic fluid tube, 14: oil tank, 15: hydraulic pump, 16: solenoid valve, 17: hydraulic piping, 18: Pressure transmitter, θ ₁ : Filtration chamber filling time, θ ₂ : Filtration time, q ₁ : Optimal stock solution injection speed, q ₂ : Filtration chamber filling solution injection speed.

Claims (1)

[Claims] 1. A filter press for separating a cake and a filtrate by pressurizing a high-concentration stock solution into a filter chamber formed by a filter cloth and a filter plate at a high pressure, with the start of filtration as a reference time, and the filtration after the reference time. While the process is in progress (filtration time θ ₂ ), the high-concentration stock solution is supplied at the optimum stock solution injection speed q ₁ , and while the stock solution is being supplied to the filter chamber before the reference time (filter chamber charging time θ ₁ ). Is a high-pressure filter press stock solution injection method in which a high-concentration stock solution is supplied at a filtration chamber filling solution stock solution injection rate q ₂ which is larger than q ₁ .