JPS6031879A - Pressure float concentration apparatus - Google Patents

Abstract

PURPOSE:To compensate a leak by balancing the inflow amount and the outflow amount to a pressure tank, by interlocking a booster pump and a vacuum pump through a variable reduction gear, and providing a pressure regulating valve to the vacuum pump side. CONSTITUTION:For example, when a leak is generated from the high pressure side to the low pressure side in a booster pump 18, the outflow amount from a pressure tank 7 by a vacuum pump 14 increases in quantity as compared with the inflow amount to the pressure tank 7 by the booster pump 8 and, as a result, the water level in the pressure tank 7 is gradually lowered. Because a leak amount comes to a nearly constant value by the characteristics of a pump system, a variable reduction gear 15 is preset manually corresponding to the lowering in the water level and the speed of the booster pump 8 is made faster than that of the vacuum pump 14 to supply pressurized water to the tank 7 in an amount corresponding to the lowering amount in the water level. In addition, the small variation of the water level in the pressure tank 7 is detected by a level meter 18 and the emitting amount from the vacuum pump 14 is adjusted by a pressure regulating valve 17.

Description

[Detailed description of the invention] The present invention relates to a pressurized flotation concentrator.

When concentrating sludge, this sludge is mixed with pressurized air-dissolved water, the mixed liquid is discharged to the bottom of the pressure flotation thickening tank, and the above-mentioned pressurized dissolution is performed based on the drop in water pressure caused by the rise of this mixed liquid. There is a so-called pressure flotation concentration method in which air is bubbled, the bubbles are attached to the sludge, the sludge is floated and separated, and the separated water is discharged downward to concentrate the sludge. Also,
The pressure of pressurized water is increased, and compressed air is blown into the pressurized water after the pressure increase in a pressurized tank (mixed air tank).

There is a low-pressure mixing method in which this air is dissolved and the pressurized air-dissolved water is once depressurized and mixed with sludge.

By the way, in the low-pressure mixing method, it is necessary to once increase the pressure of pressurized water and then reduce the pressure again after dissolving the air. Therefore, if the booster pump and the pressure-reducing pump are connected in conjunction with each other, the pressure in the system will be the same as that of the booster pump during operation. However, since it acts as a driving force on the decompression pump, these forces act in a direction that cancels each other out, and there is an advantage that this amount of energy can be recovered. It is desirable to use positive displacement pumps as the pressure boosting pump and the pressure reducing pump, but this positive displacement pump has a problem in that leakage of pressurized water from the high pressure side to the low pressure side is unavoidable. That is, depending on the pressure difference between the high-pressure side and the low-pressure side, a pressure-boosting pump works in a direction where the flow rate decreases, and a pressure-reducing pump works in a direction where the flow rate increases, causing a problem that the water level in the pressurized tank decreases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to compensate for leakage when a booster pump and a pressure-reducing pump are connected in conjunction with each other, thereby balancing the amount of inflow and outflow to a pressurized tank.

In order to achieve this object, the present invention makes the discharge side of a positive displacement booster pump that boosts the pressure of separated water in a pressurized flotation concentration tank face a pressurization tank that sends compressed air into the pressurized water to dissolve it. A positive displacement pressure reducing pump is provided to reduce the pressure of the pressurized air-dissolved water from the pressurized tank in conjunction with the passenger displacement booster pump, and the pressure of the reduced-pressure air-dissolved water is adjusted and then mixed with the sludge. A pressure regulating valve is provided, and a variable speed reduction device is provided to interlock the positive displacement carp pressure pump and the positive displacement pressure reducing pump.

Therefore, even if a predetermined amount of pressurized water is no longer supplied from the boost pump to the pressurized tank due to a leak in the boost pump, the variable speed reducer allows the boost pump to be faster than the pressure reducer pump, and the pressure regulating valve Since the discharge amount from the decompression pump can be reduced, the amount of outflow from the pressurized tank by the decompression pump and the amount of inflow into the pressurized tank by the booster pump can be balanced, and the leak can be compensated for. It becomes possible to maintain the water level in the pressure tank and secure a predetermined amount of water.

An embodiment of the present invention will be described below with reference to the drawings.

In the drawing, (1) is a sludge storage tank, to which is connected a positive displacement sludge pump (3) for supplying sludge in the tank to a mixer (2). (4) is a motor. - 10,000 (5) is a separation water tank that stores the separated water in the pressurized flotation concentration tank (6) as pressurizing water, and is a volumetric type that increases the pressure of the separated water in the tank and sends it to the pressurizing tank (7). A boost pump (8) is connected. In the pressurized tank (7).

Compressed air is supplied from the air compressor (9) through the air tank (a), the flow rate control valve α, and the pressure adjustment valve (2), and this compressed air is blown into the pressurized water and dissolved. It has become. Pressure adjustment valve ■ is pressurized tank (7)
The opening is adjusted by a signal from the pressure sensor.

(141 is a positive displacement pressure reducing pump that reduces the pressure of pressurized air-dissolved water from the pressurized tank (7), and this pressure reducing pump α and 011 boost pump (8) are connected to the variable speed reducer (to)
are linked to each other via. qQ is both pumps (8)
This is a motor for driving (g). Also a'tt
is a pressure regulating valve that regulates the pressure of the reduced pressure flow pressurized air-dissolved water from the reduced pressure pump o4 and then guides it to the mixer (2).
) The opening is adjusted by the signal from the level meter [phase]. (g) is the pressure reducing pump 9 tatami and the pressure regulating valve a'
I) is a pressure indicator between the In addition, the mixer (
2), sludge and decompressed pressurized air-dissolved water are mixed under low pressure, and the mixed liquid is supplied to the pressurized flotation concentration tank (6).

According to this configuration, the pressurized water in the one-separation water tank (5) is pressurized by the positive displacement booster pump (8) and then sent to the pressurizing tank (7). The air is dissolved and the pressure is reduced once by the positive displacement pump σ→.
After being pressure regulated, that is, further reduced in pressure, by the pressure regulating valve Qη, it is sent to the mixer (2). Further, the sludge in the sludge storage tank (1) is sent to the mixer (2) by the sludge pump (3), and mixed with pressurized air-dissolved water at low pressure in the mixer (2).

The mixed liquid is discharged into a pressurized flotation concentration tank (6), the sludge is floated and separated, and the separated water is sent to a separation water tank (5) and circulated within the system. The floated sludge is discharged to the outside by a sludge discharge device installed on the water surface of the pressurized flotation thickener tank (6) (not shown)
.

At this time, for example, if a leak occurs from the high pressure side to the low pressure side in the boost pump (8), the amount of flow from the pressurized tank (7) caused by the pressure reducing pump α◆ will be
As a result, the water level in the pressurized tank (7) gradually decreases. Since the amount of leakage is a nearly constant value depending on the characteristics of the pump system, etc., the variable speed reducer (G) is manually set in advance to accommodate this, and the boost pump (8) is used rather than the decompression pump (B) and JL. The speed is increased to supply pressurized water in an amount corresponding to the water level drop into the pressurized tank (7). Also,
If there are small fluctuations in the water level in the pressurized tank (7), such as daily fluctuations, this will be detected by the level meter (b) and the pressure regulating valve α will be activated.
Adjust the opening of η to adjust the discharge amount from the pressure reducing pump α◆. That is, the variable speed reduction gear 011 is to be roughly adjusted, and the pressure regulating valve αη is to be finely adjusted.

These will maintain the water level in the pressurized tank (7).

As described above, according to the present invention, even if a predetermined amount of pressurized water is not supplied from the boost pump into the pressurized tank due to a leak in the boost pump, the boost pump is sped up more than the pressure reducer pump by the variable speed reducer. At the same time, the discharge amount from the pressure reducing pump can be restricted by the pressure regulating valve, so the amount of outflow from the pressurized tank due to the pressure reducing pump and the amount of inflow into the pressurized tank due to the boosting pump are balanced, and the ffQ Can compensate for leaks.

It becomes possible to maintain the water level in the pressurized tank and secure a predetermined amount of water.

[Brief explanation of drawings]

The drawings are diagrams showing a schematic configuration of an embodiment of the present invention. (2) - ° Mixer, (5)...separation water tank t (a)
”' Pressurized flotation concentration tank, (7) ... Pressurized tank, (8
)...Positive displacement boosting pump 1a◆...Positive displacement pressure reducing pump, (G)...Variable speed reducer, ση...Pressure regulating valve agent Yoshihiro Morimoto

Claims (1)

[Claims] 1. The discharge side of the positive displacement boost pump that boosts the pressure of the separated water in the pressurized flotation concentration tank faces the pressure tank that sends compressed air into the pressurized water to dissolve it, and is linked to the positive displacement boost pump described in n. A positive displacement pressure reducing pump is provided to reduce the pressure of the pressurized air dissolved water from the pressurized tank, and a pressure regulating valve is provided to guide the reduced pressure air dissolved water to a mixer where it is mixed with sludge after regulating the pressure. A pressurized flotation concentrator characterized in that a variable speed reduction device is provided for interlocking the positive displacement boost pump and the positive displacement decompression pump.