JPH0457363B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention particularly relates to an improvement in a method for pressurizing raw liquid into a pressure filter using a pressurizing tank.

Conventional Technology Conventionally, there have been the following four typical methods for pressurizing raw liquid into a pressure filter.

First, as shown in FIG. 2, there is a method in which the stock solution is directly pumped from the stock solution storage tank 1 into the pressure filter 3 using a spiral pump 2.

A second method is to use a reciprocating pump such as a diaphragm pump or a plunger pump instead of the spiral pump 2.

A third method uses the arrangement shown in FIG. In FIG. 3, the same parts as in FIG. 2 are given the same reference numerals. In the arrangement shown in FIG. 3, the stock solution storage tank 1 is connected to a pressurized tank 4 via a supply pump 2A. The top of the pressurized tank 4 is connected to a pressurized air supply device 6 through a pipe 5.
is provided with a valve 7. This valve 7 and press-fit tank 4
The pipe 5 can communicate with the atmosphere through a pipe 8 between the two. A valve 9 is provided on the pipe 8, and by opening the valve 9, the upper space of the press-fit tank 4 can be communicated with the atmosphere.

During low-pressure injection, the valves 7 and 9 are closed, and the stock solution is directly forced into the pressure filter 3 from the stock solution storage tank 1 by the supply pump 2A. During high-pressure press-fitting, the valve 9 is first opened, the valve 7 is closed, and the stock solution is supplied from the stock solution storage tank 1 to a predetermined liquid level in the press-fit tank 4 by the supply pump 2A. Next, the valve 7 is opened, the valve 9 is closed, and pressurized air is supplied from the pressurized air supply device 6 to the pressurized tank 4 to press the liquid level of the stock solution accumulated there with the pressurized air. The stock solution is pressurized into the pressure filter 3.

The fourth method is to perform low-pressure press-fitting with a spiral pump and high-pressure press-fit with a reciprocating pump.

Problems to be Solved by the Invention Pressure filtration machines have a low pressure loss on the filtration surface in the early stages of filtration, so they can process a large amount of filtration, but as time passes, cake adheres to the filtration surface from the middle to the late stages of filtration. The pressure loss on the filtration surface gradually increases, and the filtration throughput becomes very small. Under these circumstances, the above conventional method has the following problems.

In the first method, due to the characteristics of the spiral pump, press-fitting can be carried out efficiently at low pressure, but when press-fitting at high pressure, the efficiency decreases and the pump becomes overheated, which places a very heavy burden on the pump. Therefore, this first method is suitable for low-pressure press-fitting, but not for high-pressure press-fitting.

The second method, contrary to the spiral pump, injects a fixed amount at a time, so it cannot keep up with the throughput of the pressure filter during low-pressure press-in, which requires large-capacity press-in.
It just takes more processing time. Therefore, this second method is suitable for high-pressure press-fitting, but not for low-pressure press-fitting.

The third method aims to improve the first method, but the maximum pressure is limited to 10Kg/cm ² from the viewpoint of safety and maintenance of the pressure tank, and high pressure press-fitting is not possible.
Now that it is common to use 15Kg/ ^cm2 ,
The scope of application is very narrow.

The fourth method is currently the most widely used,
Since there are a large number of pumps, there is a problem that equipment costs and operating costs are high.

Means for Solving the Problems An object of the present invention is to provide a novel method that can solve all the problems of the conventional methods described above.

In order to achieve this object, the present invention provides a reciprocating pressure booster pump operated by gas in the pressure injection piping of a stock liquid injection device using a pressure injection tank of a pressure filtration machine, and uses the pressurized gas of the pressure injection tank as a driving gas. It is branched out from the chamber, and during low-pressure press-fitting, the press-fitting tank and booster pump are not operated, and the low-pressure press-fitting pump alone is used for press-fitting, and during high-pressure press-fitting, the pressure-fitting is performed using the sum of the pressure in the press-fitting tank and the boosting pressure of the pressure booster pump. Provided is a method for pressurizing raw liquid into a pressure filter, which is characterized by carrying out the following steps.

Function In the above arrangement, only the low pressure pump operates during low pressure injection, supplying an amount of stock solution that follows the throughput of the pressure filter, and during high pressure injection, the stock solution can be supplied at high pressure although the supply amount is small. High-pressure press-fitting is performed using the sum of the pressure inside the press-fit tank and the pressure of the booster pump.

Embodiment The following description will be made based on the arrangement according to the principle of the present invention shown in FIG.

In FIG. 1, the same parts shown in FIGS. 2 and 3 are given the same reference numerals. In this arrangement,
A pressure booster pump 10 is arranged between the pressure tank 4 and the pressure filter 3, and this pressure booster pump 10 switches the pressurized air from the pressurized air supply device 6, the pressure tank 4, or both from four directions. It includes a gas differential pressure generating device 12 which is received via a valve 11. This gas type differential pressure generating device 12 has a pair of pistons 13 that move in opposite directions, and each of these pistons is combined with a corresponding reciprocating pump 14. Each reciprocating pump 14 has a diaphragm 1
Includes 5.

As is clear from FIG. 1, in this pressure booster pump 10, when one reciprocating pump 14 increases pressure, the other reciprocating pump receives the pressure, and the inflow pressure generated at the time of acceptance increases. The signal is transmitted to the reciprocating pump on the pressure side.

The booster pump 10 is bypassed through a low-pressure press-in pipe 16, and this low-pressure press-in pipe 1
6 is provided with a check valve 17.

In this arrangement, it is assumed that the discharge pressure of the press-in pump 2 and the pressure of the pressurized air are the same. At the time of low-pressure press-fitting, first, the valves 7 and 9 are closed, and the press-fitting pump 2 is operated. At this time, the stock solution passes directly through the pressure tank 4 from the stock solution storage tank 1, bypasses the pressure booster pump 10, and is supplied to the pressure filter 3 through the low pressure pressure pipe.

As the filtration process progresses, cake adheres to the filter surface,
As the pressure loss gradually increases, the press-fitting pressure also increases in proportion to it. When the pressure sensor 18 senses a predetermined pressure, the valve 9 is opened and the press-fitting tank 4
The liquid level of is raised to LS _H. Therefore,
The exhaust gas from the pressurized tank 4 is sent to the booster pump 10,
This pressure booster pump 10 operates. The press-fitting pressure at this time is the sum of the discharge pressure of the press-fitting pump and the boosting pressure of the booster pump.

When the liquid level in the press-fit tank 4 reaches LS _H ,
The valves 7 and 9 are opened, the press-in pump 2 is stopped, and the stock solution in the press-in tank is pressurized with the sum of the pressure of the pressurized air and the boosting pressure of the booster pump.

When the liquid level in the press tank 4 reaches LS _L , the press pump 2 is operated, the valve 7 is closed, the valve 9 is opened, and the press pump 2 is operated until the liquid level reaches LS _H. During this period, the press-in pressure is increased by the pressure booster pump 10 operated by the discharge pressure of the press-in pump 2 and the exhaust of the press-fit tank.
is the sum of Repeat this until filtration is complete.

It should be noted here that the booster pump 10 uses two reciprocating pumps 14. With conventional reciprocating pumps, no matter how high the push-in pressure was, in order to raise the pressure above it, the pressure could not be increased unless power was applied that was equivalent to pressurizing something at 0 pressure.However, with the present invention, In the structure according to the above, since the pushing pressure acting on the piston is balanced, it is only necessary to apply power corresponding to the amount of pressure applied by the differential pressure generating device 12.

Effects of the Invention According to the present invention, if the piston diameter of the pressure booster pump 10 and the cylinder diameter of the differential pressure generator are the same, the press-in pressure to the filter can be made approximately twice the pressure in the press-in tank. Therefore, using a press-fit tank, it is possible to operate with high efficiency at a press-fit pressure exceeding 10 kg/cm ² .
Even in this case, the pressure in the press-fit tank can be maintained at 10 kg/cm ² or less. Moreover, the stock solution can be replenished into the press-in tank without lowering the press-in pressure, and the air discharged at this time can also be used effectively, so operating costs are also extremely low.

[Brief explanation of the drawing]

FIG. 1 is a schematic illustration of an arrangement for carrying out the method according to the invention. FIG. 2 is a diagram showing a conventional arrangement. FIG. 3 is a diagram showing another conventional arrangement. In the drawings, 1... Raw solution storage tank, 2... Pressure pump, 3... Pressure filter, 4... Pressure tank, 6
... Pressurized air supply machine, 7, 9 ... Valve, 10 ... Pressure booster pump.

Claims (1)

[Scope of Claims] 1. A reciprocating pressure booster pump operated by gas is provided in the press piping of a stock liquid press-in device using a press-fit tank of a pressure filtration machine, and driving gas is branched from the pressurized gas chamber of the press-fit tank. During low-pressure press-fitting, the press-fitting tank and booster pump are not operated, and the low-pressure press-fitting pump alone is used for press-fitting, and during high-pressure press-fitting, the press-fitting is performed using the sum of the pressure in the press-fitting tank and the pressure from the booster pump. A method for pressurizing raw liquid into a pressure filtration machine. 2. In the method for pressurizing raw liquid according to claim 1, the pressure boosting pump is two reciprocating pumps, and these reciprocating pumps are connected via a gas-type differential pressure generator. , when one reciprocating pump increases pressure, the other reciprocating pump receives it, and the inflow pressure generated at the time of acceptance is transmitted to the reciprocating pump on the pressure increasing side. A method of press-fitting raw liquid.