Description Gravity separator for oil with high functional versatility The present patent application refers to a gravity separator for oil characterised by the possibility of adjusting the operation mode based on the way the separator is fed with a mixture of water and oil.

As it is known, static separators are used in olive oil production to separate oil and water starting from the liquid mixture obtained when olive paste (which is the result of olive smashing) is processed inside special machines, such as presses or similar equipment.

Traditionally, gravity separators consist in a tank, preferably with rectangular shape, where a liquid mixture of oil and water is introduced continuously. The mixture separates by decantation in the separator, producing two continuous flows of oil and water.

This type of separators is provided with a hole for the introduction of the mixture of water and oil situated on a lateral wall and holes for the extraction of water and oil in separate form on the opposite lateral wall. More precisely, the introduction hole is situated near the bottom of the tank, and the two extraction holes are situated near the top of the tank, although the extraction hole of the water is situated at a lower height than the extraction hole of the oil.

The operation principle of this type of device is based on two natural phenomena. Reference is made to the natural capability of oil to float on water (due to lower density) and to the principle of communicating vessels.

Gravity separators are provided with an internal partition wall that forms two separate chambers with a communication space on the bottom; this is due to the fact that the lower edge of the partition wall does not reach the bottom of the tank and ends at a few centimetres from the bottom.

The first of the two chambers (which normally has a much larger capacity than the first chamber) receives the liquid mixture of water and oil through the introduction hole. In this chamber, spontaneous decantation

makes oil float on water and water remain in the lower section of the tank.

In this way oil can be poured out of the separator through the extraction hole situated on the lateral wall of the tank at the top of the decantation chamber.

The water in the lower section of the tank spontaneously tends to be poured into the second chamber through the passage on the bottom of the tank.

Since the second chamber is only filled with water, only water can be poured out through the extraction hole located at the top of the chamber, at a lower height than the extraction hole for oil situated at the top of the decantation chamber.

Because of the difference in height between the two extraction holes (the lower hole for water and the upper hole for oil), by applying the principle of communicating vessels incorrectly, one might assume that the water poured into the second chamber is poured out as soon as it reaches the level that corresponds to the height of the extraction hole, thus preventing the oil contained in the first chamber from reaching the level that corresponds to the higher height of the hole.

However, it must be considered that, due to the. different specific gravity of oil and water, when the free surface of the water contained in the second chamber touches the extraction hole, the free surface of the oil in the decantation chamber is situated at a higher height that basically corresponds to the height of the extraction hole.

By knowing the difference in the specific gravity of water and oil and the depth of the tank, one might calculate the difference in height that must be given to the holes to ensure the formation of a layer of floating oil with considerable height in the decantation chamber, when the two separate fluids start overflowing from the corresponding holes, with no risk for the deeper oil to be poured into the second chamber, passing under the partition wall that practically acts as an inverted overall.

Nevertheless, the traditional technology is impaired by considerable drawbacks. Because of this, large operators in this sector have abandoned

the use of similar separators and prefer installations based on a different operating principle, although more expensive, such as centrifugal machines able to separate oil and water in shorter time and with higher efficacy.

The high purchasing and running cost of these sophisticated machines makes it impossible for small oil producers to use this modern type of equipment.

As a solution for the specific requirements of smaller oil producers, the applicant has decided to innovate the technology used for gravity separators in order to find a remedy to the functional limitations that currently impair them.

The purpose of the present invention is to design a device that can guarantee high functional features with costs that are basically aligned to the costs of traditional separators.

In order to demonstrate the advantages of the present invention, it is necessary to illustrate the functional limitations of traditional separators.

Generally speaking, the inconveniences are related to the operation rigidity of these devices, represented by the impossibility of adjusting to the different modes used to feed the devices and/or the different density of processed oils.

The first drawback that impairs traditional gravity separators consists in the impossibility to check the turbulence of the liquid mixture of water and oil introduced in the decantation chamber. Of course, turbulence depends on the higher or lower flow speed of the mixture introduced in the separator through the feeding hole.

When the speed of the incoming flow is too high, considerable turbulence is generated in the liquid mixture inside the decantation chamber.

Turbulence, of course, reduces the efficacy of decantation and the separation of oil and water at the end of the process is rather imperfect.

Currently, the speed of the liquid mixture (and consequently of the turbulence produced inside the decantation chamber) introduced in the decantation chamber can be only adjusted empirically, after checking the higher or lower concentration of the oil that flows out of the extraction hole (and the higher or lower grade of dirty water flowing out of the corresponding

hole).

In other words, the user cannot check in real time the negative effect of turbulence that prevents separation of the two liquids at a different density, either during the initial stage or in full operation. The user needs to control the thickness of the layer of floating oil that is gradually formed, maintained and/or drained during operation with or without introducing the tank of the mixture of oil and water in the tank, it being evident that the deeper the layer is, the purer the decanted oil will be.

Likewise, the user cannot control the variation of the floating layer of oil when the separator is in full operation, although the layer of floating oil must be maintained within a range of predefined values to avoid the risk for the oil to be poured and dispersed in the water separation tank on one side, and the possibility that not perfectly separated oil may flow out of the decantation chamber.

The second drawback refers to the impossibility of adjusting the separation modes of water and oil based on an important parameter, which is the specific density of the different oils introduced in the main chamber of the separator as part of the mixture to be decanted.

The importance of this parameter is related to the fact that oil with lower density has a considerably lower specific gravity compared to oil with higher density. Because of the principle of communicating vessels, the difference in level between the free surface of the oil in the first chamber and the free surface of the water in the second chamber increases inversely proportional to the specific gravity of the oil introduced in the separator.

In case of traditional gravity separators, the decantation modes cannot be adjusted according to the different density of the oil.

Although it is true that the free surface of the oil at the top of the first chamber-i. e. the decantation chamber-and the free surface of the water in the second chamber can change their mutual distance according to the specific gravity of the oil, it is also true that the distance between the two extraction holes remains unchanged.

Because of the structural rigidity of traditional separators, oils with

lower density, which without the hole of the first chamber and with the same layer of oil would tend to be situated at a higher level than the hole, are poured before they reach this theoretical level.

If we consider that the oil on the free surface of the mixture is the oil subjected to maximum decantation, it appears evident that the oil extracted from the decantation tank before it has reached the theoretical level has a purity degree (meant as absence of water) lower than the maximum permitted value.

As mentioned earlier, the present invention has found a solution to these two technical-functional limitations of traditional separators.

In particular, in order to avoid the problem due to turbulence produced in the mixture of oil and water, the separator of the invention has been equipped with at least one transparent vertical wall ; it being also provided that transparency can be extended to the entire surface of each wall or, possibly, to a single narrow window with vertical direction from the base to the top in one of the walls in the decantation chamber.

This allows the user to visually check the negative effect on separation of the turbulence produced when the mixture of oil and water is introduced in the decantation chamber. Direct control allows the user to adjust the incoming flow of liquid mixture with the highest accuracy and immediately (before the oil is poured outside) and, mostly important, reduce the speed of the flow whenever dangerous turbulence is produced inside the decantation chamber.

In order to adjust the operation mode of the separator of the invention to different oil density, the extraction holes of water and oil have been externally provided with curved adjustable nozzles.

A first section of the nozzles is inserted horizontally into the extraction hole situated on the lateral wall of the separator, with the possibility of rotating around its longitudinal axis; in this way, the adjacent 90° curved section can be rotated and blocked in any position from the horizontal position to the upward vertical position and vice versa.

Since the water and oil that tend to flow out from the extraction holes

can be poured out only after they reach the exit section of the curved nozzles inserted into the holes, it appears evident that the simple rotation of one of the nozzles can change the height of the pouring section of the corresponding liquid.

More precisely, the variation in height of the pouring section can occur within a range that corresponds to the distance between the height of the extraction hole on the lateral wall of the separator and the maximum height of the exit section of the nozzle, when the external section of the nozzle is in perfect upward vertical position.

For example, if the liquid mixture introduced in the separator comprises oil with low density, and therefore low weight, it appears evident that the free surface of the oil in the decantation chamber tends to be placed (with the same layer of oil being separated on water) at a higher height than the height of the extraction hole situated on the lateral wall of the separator.

In this case, however, by suitably rotating the nozzle inserted in the fixed extraction hole, the exit section of the same nozzle can be brought to the same height as the free surface of the oil that allows the maximum value of the layer, thus extracting oil with maximum purity.

In this case, of course,. a similar rotation of the adjustable nozzle inserted into the extraction hole of the water would restore the same standard difference in level between the oil and water extraction sections at a different height.

This"fine tuning"operation can be performed with high accuracy because the separator of the invention has one or more transparent walls that allow the user to check the exact height of the free surface of the oil in the decantation chamber and, mostly important, monitor the depth of the layer of floating oil in the decantation chamber.

The possibility of adjusting the difference in height between the pouring section of oil and water allows the user to adjust (and possibly maximise) the decantation time of the oil according to the specific gravity of the different oils introduced in the separator from time to time, thus adjusting it to the capacity of the mixture of oil and water introduced in the device.

For major clarity, the description of the invention continues with reference to the enclosed drawings, which are intended for purposes of illustration only, and not in a limiting sense, whereby: - figure 1 is a diagrammatic axonometric view of the separator of the invention ; - figure 2 is a cross-section of figure 1 with a longitudinal plane ; - figure 3 is the same as figure 2, except for the fact that it refers to an alternative embodiment of the separator of the invention.

With reference to the enclosed figures, the separator of the invention comprises a parallelepiped-shaped tank (1) with rectangular base, having an internal partition wall (2) that occupies the entire width of the tank (1) and creates two different chambers (3,4), with the first chamber (3) with larger volume and capacity acting as decantation chamber for the mixture of water and oil.

In the embodiment shown in the aforementioned, figures the partition wall (2) is fixed at 45° against the internal side of the front wall (1a) of the tank (1) on top; the lower edge (2a) is situated at a certain height from the bottom of the tank (1), leaving a passage (S) to make the two chambers (3,4) communicate.

The back wall (1b) of the tank has a wall (5) near the bottom that allows for continuous introduction of the mixture of water and oil directly into the decantation chamber (3).

The front wall (1a) has holes (6,7) used for continuous extraction of water and oil after separation.

As shown in the aforementioned figures, the outflow hole of the oil (6) is situated on the top of the decantation chamber (3) before the partition wall (2); the outflow hole of the water (7) is situated on the top of the second chamber (4) after the partition wall (2) and, consequently, at a lower height than the outflow hole of the oil (6).

As mentioned earlier, the peculiarity of the separator of the invention (1) consists in the fact that at least one of the vertical walls is totally or partially transparent. In the embodiment shown in the aforementioned figures

one of the lateral walls (1 c) has a transparent window (8) that extends for the entire height of the wall and allows the user to control the turbulence of the liquid mixture, the height of the free surface of the oil in the upper section of the decantation chamber (3), and the depth of the layer of floating oil in the decantation chamber (3).

Another innovative feature of the device of the invention is related to the presence of two adjustable elbow nozzles (9,10) in external position on the front wall (1a), inserted into the outflow hole of the oil (6) and the outflow hole of the water (7), respectively.

As mentioned above, the nozzles (9,10) have a first section (9a, 10a) inserted horizontally into the corresponding hole (6,7) with the possibility of rotating freely around its longitudinal axis. The first section (9a, 10a) is joined at about 90° with a second section (9b, 10b) that varies its position with respect to the outflow hole (6,7) due to the rotation of the fixed section (9a, 10a).

By rotating the nozzles (9,10) the user can adjust the height of the exit sections (9c, 1 Oc) as desired, modifying the depth of the layer of floating oil in the decantation chamber (3) according to the specific requirements..

Moreover, the front wall (1 a) is provided with a drainage hole (11) used to drain the tank (1) completely and a lid (12) used for inspections and cleaning. With reference to figure 2, the separator of the invention can be provided with a typical lamella pack (13) to favour decantation, since the contact with the inclined plates makes the oil drops raise towards the top of the decantation chamber (3) and the water drops fall towards the bottom.

Figure 3 shows a preferred embodiment of the separator of the invention, in which the partition wall (20) dividing the chambers (3,4) has is perfectly vertical.

According to this alternative embodiment of the separator, the drainage hole of the oil (6) is situated on the opposite side with respect to the drainage hole of the water (7), with the usual difference in height between the two holes.

The present invention can be advantageously applied also to the

second embodiment of the separator, meaning that one or more of the vertical walls are completely or partially transparent to allow for the internal vision of the first chamber (3) in its entire height.

Also in this case, the two drainage holes (6,7) are provided with adjustable elbow nozzles (9,10), having the same structure and operating principle as the ones illustrated with reference to the separator of figure 1.