JP7615435B2 - Oil-water separation system - Google Patents

Description

The present invention relates to an oil-water separation system, and in particular to a system used to recover the upper layer of oil-water that contains floating oils and fats in an oil-water separation tank such as a grease trap.

Wastewater from kitchens such as restaurants contains grease, leftover food, vegetable scraps, and other materials. Grease traps are installed to prevent these materials from clogging drains and drainage pipes and flowing directly into the sewer. Grease traps temporarily store wastewater so that the grease and other materials contained in the wastewater do not flow directly into the sewer system. If wastewater is left stored in these traps, it can lead to bad odors and the growth of pests.

Patent Document 1 describes an oil-water separation system that includes a collection vessel that uses suction means to collect the oil-containing liquid in an oil-water mixture, and an oil-water separation means that separates the oil and water in the oil-containing liquid collected in the collection vessel. The collection vessel is composed of a bottomed, cylindrical vessel body having an outlet at the bottom for suctioning and discharging the oil-containing liquid, and a floating cylinder that is fitted and arranged within the vessel body at a predetermined interval so that it can move up and down. A float that floats the floating cylinder near the liquid surface of the oil-water mixture is integrally provided with the floating cylinder, and the oil that floats on the surface of the oil-water mixture can be collected well without air being mixed in. In addition to this oil-water separation system, there is also a device that uses a pair of spherical floats to suck up oil with a floating cylinder.

JP 2003-154202 A

However, in the oil-water separation system described in Patent Document 1, the opening of the floating cylinder that sucks in the oil is fixed at a position slightly lower than the liquid level of the oil-water mixture, which causes problems such as oil clumps getting caught in the opening of the floating cylinder and the inability to attract oil that is far from the opening, resulting in low recovery efficiency.

The present invention was made in consideration of the problems with the above-mentioned conventional technology, and aims to provide an oil-water separation system that can efficiently attract and recover even clumps of oil or oil located far away.

To achieve the above object, the oil-water separation system of the present invention is characterized by comprising a collection vessel having a cylindrical vessel body with an outlet port at the bottom for sucking and discharging the oil-containing liquid, a cylindrical floating cylinder whose inner circumferential surface is arranged to be movable in the vertical direction along the outer circumferential surface of the vessel body, and which has an oil-containing liquid suction section at its upper part and can form an air pocket, and a water suction pump that sucks the oil-containing liquid from the outlet of the vessel body of the collection vessel and moves the floating cylinder back and forth in the vertical direction relative to the vessel body to float and sink the oil-containing liquid from the surface of the oil-containing liquid.

According to the present invention, the floating cylinder reciprocates vertically, floating and sinking on the surface of the oil-containing liquid, so that even clumps of oil or oil located far away can be efficiently attracted and collected.

In the above oil-water separation system, the suction section of the floating cylinder can be formed in a cone shape that opens upward and gradually decreases in opening diameter as it descends. This allows the sucked-up oil-containing liquid to be quickly guided to the container body.

In the above oil-water separation system, the difference between the outer diameter of the container body and the inner diameter of the floating cylinder can be 1 mm or less. This allows stable sliding between the container body and the floating cylinder, and balances the water pressure difference between the inside and outside of the collection container.

In the above oil-water separation system, the piping on the outlet side of the suction pump can be equipped with a valve for adjusting the suction power of the suction pump. This allows the range of the vertical reciprocating motion of the floating cylinder to be adjusted according to the properties of the oil-containing liquid.

As described above, the present invention provides an oil-water separation system that can efficiently attract and recover even clumps of oil or oil located far away.

1 is an overall configuration diagram showing one embodiment of an oil-water separation system according to the present invention. 2 is a partial cross-sectional view showing a collection vessel, a water intake pump, etc. of the oil-water separation system shown in FIG. 1. This figure is primarily for explaining the operation of the collection vessel shown in Figure 2, in which (a) shows the floating cylinder in its initial position, (b) shows the suction part of the floating cylinder submerged below the water surface, and (c) shows the suction part of the floating cylinder floating above the water surface.

Figure 1 shows one embodiment of the oil-water separation system according to the present invention. This oil-water separation system 1 includes a grease trap 7 equipped with a collection vessel 5 and a water intake pump 6, an oil-water separation tank 9 for storing the oil-containing liquid F1 (F2) recovered in the grease trap 7, an oil-water transfer pump (hereinafter referred to as the "transfer pump") 10 for recovering the oil-rich oil-water F3 remaining on the surface of the oil-water separation tank 9 and transporting it to an oil recovery tank 11, and an operation panel 8 for controlling the operation of the water intake pump 6 and the transfer pump 10.

The grease trap 7 is equipped with a basket 2 for collecting food scraps, vegetable waste, etc. contained in the wastewater D from a kitchen such as a restaurant, a collection container 5 for collecting the oil-containing liquid F1, and a suction pump 6.

As shown in Figure 2, the inlet side of the suction pump 6 is connected to a collection vessel 5 having a cylindrical vessel body 3 with a discharge port 3a at the bottom for suction and discharge of the oil-containing liquid F1, and a cylindrical floating cylinder 4 whose inner circumferential surface is arranged to be movable in the vertical direction along the outer circumferential surface of the vessel body 3, has a suction section 4a for the oil-containing liquid F1 at the top, and can form an air reservoir 4b.

The suction section 4a of the floating cylinder 4 of the collection container 5 is formed in a cone shape that opens upward and gradually decreases in opening diameter as it descends. In addition, the difference between the outer diameter of the container body 3 and the inner diameter of the floating cylinder 4 is 1 mm or less. A cylindrical section 4c is provided at the bottom of the suction section 4a.

A valve 12a is provided on the piping 12 at the outlet side of the suction pump 6 to adjust the suction power of the suction pump 6.

As shown in FIG. 1, an oil suction pipe 10a of a conveying pump 10 is installed inside the oil-water separation tank 9. Also installed inside the oil-water separation tank 9 are an oil-water partition pipe 9a with a notch at the bottom and a drain pipe 9b that opens below the water level inside the oil-water partition pipe 9a, and a drain pipe 9c equipped with a drain valve (not shown) for returning water accumulated at the bottom to the grease trap 7 is installed at the bottom of the oil-water separation tank 9. The oil-water separation tank 9 and the oil and grease recovery tank 11 are connected at the bottom by a communication pipe 13.

In addition to the above devices, the oil-water separation system 1 also includes appropriate valves for tap water used during oil recovery, maintenance, and cooling.

Next, the operation of the oil-water separation system 1 having the above configuration will be explained with reference to Figures 1 to 3.

Wastewater D from kitchens such as restaurants is dumped into a grease trap 7, and food scraps, vegetable scraps, etc. contained in the wastewater D are collected by a basket 2. Next, the oil-containing liquid F1 on the water surface of the grease trap 7 is collected by a collection container 5 and a water suction pump 6. By operating the water suction pump 6 about 20 times a day, for about two minutes each time, the inside of the grease trap 7 can be kept constantly clean.

The recovery operation of the oil-containing liquid F1 using the collection container 5 and the water suction pump 6 will now be described in detail.

When the suction pump 6 is stopped, as shown in Figure 3(a), the suction part 4a of the floating cylinder 4 of the collection vessel 5 is located about 1 cm above the water surface S of the grease trap 7 due to the buoyancy of the air remaining in the air reservoir 4b. The floating height of the suction part 4a of the floating cylinder 4 is controlled by adjusting the length of the cylindrical part 4c and the amount of air remaining in the air reservoir 4b.

When the suction pump 6 is driven, as shown in Figure 3 (b), the suction force of the suction pump 6 becomes greater than the buoyancy of the floating cylinder 4 of the collection container 5, so that the floating cylinder 4 moves downward along the container body 3, the suction part 4a of the floating cylinder 4 sinks below the water surface, and the oil-containing liquid F1 near the water surface of the grease trap 7 is sucked up by the suction pump 6.

As suction by the suction pump 6 continues, the water level in the collection vessel 5 drops and the suction pump 6 begins to suck in air along with the oil-containing liquid F1, causing the buoyancy of the floating cylinder 4 to exceed the suction force of the suction pump 6, causing the suction part 4a of the floating cylinder 4 to rise above the water surface as shown in Figure 3(c). The suction part 4a of the floating cylinder 4 then repeatedly rises and sinks below the water surface S, and when the suction pump 6 stops, it returns to the state shown in Figure 3(a).

In this way, the suction part 4a of the floating cylinder 4 reciprocates up and down, repeatedly rising and sinking from the water surface S, and by sinking the suction part 4a of the floating cylinder 4 to a certain extent, the oil clumps do not get caught in the suction part 4a and can be effectively collected. In addition, by the suction part 4a of the floating cylinder 4 repeatedly rising and sinking from the water surface S, the water surface S pulsates, attracting the floating oil and grease that is far from the suction part 4a and allowing it to be effectively collected.

In addition, the suction section 4a of the floating cylinder 4 of the collection container 5 is formed in a mortar shape with an opening diameter that gradually decreases as it descends, so the sucked oil-containing liquid F1 can be quickly guided to the container body 3. Furthermore, the difference between the outer diameter of the container body 3 and the inner diameter of the floating cylinder 4 is set to 1 mm or less, so that the sliding between the container body 3 and the floating cylinder 4 can be performed stably and the water pressure difference between the inside and outside of the collection container 5 can be balanced.

Furthermore, when the size of the semi-solid matter in the oil-containing liquid F1 is relatively large, the valve 12a of the outlet piping 12 of the suction pump 6 is adjusted to slightly increase the suction force of the suction pump 6, thereby increasing the range of the vertical reciprocating motion of the floating cylinder 4. Conversely, when the size of the semi-solid matter in the oil-containing liquid F1 is relatively small, the valve 12a is adjusted to slightly decrease the suction force of the suction pump 6, thereby decreasing the range of the vertical reciprocating motion of the floating cylinder 4, thereby allowing the oil-containing liquid F1 to be efficiently sucked in according to the size of the semi-solid matter.

The oil-containing liquid F1 collected by the suction pump 6 is transported to the oil-water separation tank 9 via the outlet piping 12 (oil-containing liquid F2), and the oil-rich oil-water F3 floating on the water surface in the oil-water separation tank 9 is collected by the transport pump 10 and transported to the oil recovery tank 11.

Meanwhile, the water separated in the oil-water separation tank 9 is returned to the grease trap 7 via the oil-water partition pipe 9a and drain pipe 9b. The top of the oil-water partition pipe 9a is slightly higher than the water level in the oil-water separation tank 9, and the oil-water partition pipe 9a has a notch at the bottom, so the inside of the oil-water partition pipe 9a is filled with water with little oil content. If the oil-water partition pipe 9a did not exist, the oil on the water surface would also be discharged when draining the water from the oil-water separation tank 9, but the presence of the oil-water partition pipe 9a makes it difficult to discharge the oil on the water surface of the oil-water separation tank 9. In addition, when cleaning and maintaining the oil-water separation tank 9, the wastewater in the oil-water separation tank 9 is drained from the drain pipe 9c. The drain pipe 9b determines the water level (amount of water) of the wastewater that accumulates in the oil-water separation tank 9 and the grease recovery tank 11.

Of the oil-rich oil-water F4 collected in the oil-and-grease recovery tank 11, the oil-and-grease F5 accumulates in the upper layer of the oil-and-grease recovery tank 11, and the separated water W is stored below it. The separated water W is returned to the oil-water separation tank 9 via the connecting pipe 13. By constantly operating the transfer pump 10 and circulating the oil-and-water F3 between the oil-and-water separation tank 9 and the oil-and-grease recovery tank 11, the separation efficiency of the oil-and-grease F5 and the water W can be increased, and a large amount of oil-and-grease F5 can be collected and stored in the oil-and-grease recovery tank 11.

In the above embodiment, an oil-water separation tank 9 and a grease recovery tank 11 are provided downstream of the grease trap 7, and the grease F5 is finally recovered in the grease recovery tank 11. However, the grease may be recovered in the oil-water separation tank 9 without providing the grease recovery tank 11. Also, a cylindrical recovery section with an open bottom can be provided inside the grease trap 7, and the recovered grease can be stored in this recovery section, forming a simple oil-water separation system using only the grease trap 7.

Although the suction pump 6 is installed in the water of the grease trap 7, a vacuum pump or the like can also be installed outside the grease trap 7 to suck up the oil-containing liquid F1. The number of collection containers 5 is not limited to one, and two or more may be provided. The shape of the suction section 4a of the floating cylinder 4 of the collection container 5 is not limited to a mortar shape, and other shapes may be used, and other configurations of the floating cylinder 4 are not limited to the illustrated example. Furthermore, a valve 12a is provided on the piping 12 on the outlet side of the suction pump 6 to adjust the range of the up and down reciprocating movement of the floating cylinder 4, but the adjustment means is not limited to this.

Reference Signs List 1 Oil-water separation system 2 Basket 3 Container body 3a Discharge port 4 Floating cylinder 4a Suction section 4b Air reservoir 4c Cylindrical section 5 Collection container 6 Suction pump 7 Grease trap 8 Operation panel 9 Oil-water separation tank 9a Oil-water partition pipe 9b Drain pipe 9c Drain pipe 10 Oil-water conveying pump 10a Oil suction pipe 11 Oil and grease recovery tank 12 Outlet side piping 12a Valve 13 Connecting pipe D Drain F1, F2 Oil-containing liquid F3, F4 Oil-rich oily water F5 Oil and grease S Water surface W Water

Claims (4)

a collecting vessel having a cylindrical vessel body with a discharge port at the bottom for suctioning and discharging the oil-containing liquid, and a cylindrical floating cylinder whose inner circumferential surface is arranged to be movable in the vertical direction along the outer circumferential surface of the vessel body, and which has an oil-containing liquid suction section at its upper portion and can form an air pocket;
An oil-water separation system characterized by comprising a suction pump that sucks oil-containing liquid from the outlet of the container body of the collection container and moves the floating cylinder back and forth in an up and down direction relative to the container body to float it above and below the surface of the oil-containing liquid. The oil-water separation system according to claim 1, characterized in that the suction section of the floating cylinder is formed in a mortar shape that opens upward and the opening diameter gradually decreases as it descends. The oil-water separation system according to claim 1 or 2, characterized in that the difference between the outer diameter of the container body and the inner diameter of the floating cylinder is 1 mm or less. 4. An oil-water separation system as claimed in claim 1, 2 or 3, characterized in that a valve for adjusting the suction power of the suction pump is provided in the piping on the outlet side of the suction pump.

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