EP0051571A1 - Emulsion siphon - Google Patents

Abstract

The syphon lift pump consists of a vertical rising column (A) with its lower end immersed in the feed tank (B) and its upper end discharging in a vacuum chamber (5). This chamber is maintained under partial vacuum by a vacuum pump (V). The vertical descent column (C) discharges into the supply tank, (D) the lower end of the column being sealed below the water level. An air injector (3) allows air, at atmospheric pressure, to enter the rising column and reduce the density of the water. This allows the use of a rising column of a height less than would be required if water at normal density were to be used.

Description

The present invention relates to an installation for lifting liquids, in particular water, of the pneumatic lifting type.

In the field of hydraulics, vertical pneumatic water pumping systems ("mammoth" pumps (air lift) and the like) which use as a control system the compressed air sent inside the conveying pipe (see "Nicklin, DJ: The Air-lift Pump: Theory and Optimization. Trans.Instn.Chem.Engrs.Vol.41-1963" and "Govier G. und Leigh Short, W.: The upward Flow of air water mixtures. The Canad.Journ.of Chem.Engineering, Oktober 1958 ") are well known and have many applications.

The installation in question consists essentially of a siphon, the descending section of which opens and discharges the liquid which passes there at a height greater than that at which the water level of the liquid contained in the supply basin of the riser.

This is made possible by the fact that while in the riser the density of the liquid is reduced by emulsifying the latter with air, in the descending section the density of the liquid returns to its initial value by separating from the emulsion - in a vacuum chamber which overcomes the riser - the air which had been used to make the emulsion, air which is then discharged to the 'outside.

The main characteristic of the invention consists in the fact that to emulsify the liquid in the riser, air is used at ambient pressure, preferably at atmospheric pressure.

In fact, as inside the riser the liquid is under vacuum, the air at atmospheric pressure is in fact compressed and can be used as such compared to the liquid contained in the riser of the siphon.

Consequently from this point of view the riser of the siphon can be considered as a particular type of air-lift whose fundamental and novelty characteristics - which differentiate it from traditional pumps of the same kind, and in particular mammoth pumps - consist to operate in a vacuum environment and to use as compressed air, in fact, air at atmospheric pressure.

In addition, while traditional air-lifters are not able to function without a sufficient depth of immersion - because, as we know, their lifting height is also subject to the immersion ratio - the pumping system described here is able to operate independently of the immersion depth which is perfectly negligible as regards the lifting height.

Obviously the emulsifier siphon object of the present invention can operate, once it has been primed, on the only condition that in the vacuum chamber into which the riser opens, the operating vacuum is kept constant.

For this purpose, an appropriate suction device must transfer outside the air which, after expanding in the riser, has flowed into the vacuum chamber where the riser opens.

It should be emphasized that, as with this installation the work necessary to allow the liquid to be lifted is limited to the suction of the air which has flowed into the time unit into the vacuum chamber, this same installation allows '' profitably use the energy of all minimum jumps, even less than one meter, which are still available in most rivers and which are not yet exploited, to accomplish the required work.

In fact, by channeling the water that must flow from upstream to downstream of the available jump in a Venturi pipe, this water can be used profitably as a suction system (Bunsen system).

It should also be noted that to aspirate, still using a Bunsen type vacuum cleaner, part of the air which has arrived in the vacuum chamber, the liquid which has been lifted by doing so can be used. drain at a height lower than that to which it was lifted. This can be particularly profitable in all cases where the work to be done is not to lift a liquid, but to aerate or oxygenate it, for example, for polluted lakes or rivers, aquaculture facilities , etc. In all these cases, with the installation which is the subject of the present invention, the energy to be spent in the oxygenation process is exclusively that necessary to transfer the residual air outside the separator. This work corresponds to the only yield losses occurring during the operating cycle.

Wind energy can be used cost-effectively to draw air from the vacuum chamber and discharge it outside.

In this case the eolic vacuum cleaner can consist simply of a rotor with two or three hollow blades and open at their end, like the hub, which form a body with the emulsifying siphon in object and which by turning back the air by centrifugation (system Andreau).

This installation is also characterized by the fact that it is extremely simple to construct; it has no dimensional limits if not to provide, in case of large flows, several pipes to breathe air; it can be operated in series, even with a single vacuum chamber; it has no moving mechanical parts, in particular if it works with a hydraulic vacuum cleaner, while if it works with a wind vacuum cleaner it does not need mechanical transmission means and therefore has an operating cost which coincides convenient- . with the cost of installation.

In addition it allows, as we have already said, the use and recovery - especially for irrigation and hydroelectric power production - of the energy of all the minimum jumps which are not used today 'hui.

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An exemplary embodiment of the foam siphon which is the subject of the present invention will be described below, indicated in schematic form in the attached drawing.

With reference to the drawing, A indicates the riser of the installation constituted by a pipe 1, the lower end of which dips into the supply basin B - for example a lake, a river, a water table and the like - of which the lake is at level h.

The upper end of the pipe 1 penetrates inside a vacuum chamber S up to a height hl greater than the height h2 of the bottom of this chamber, but less than the maximum height to which atmospheric pressure could raise, with respect to the depression established and maintained inside the chamber S, the water emulsion -air contained in the riser A, as will be better illustrated later.

The vacuum chamber S is constituted by a sealed tank 2 provided with a vacuum cleaner V intended both to create the vacuum at the determined value, and to maintain it throughout the duration of the operating cycle of the system because the water from this emulsion which flows into the chamber S separates from the air by gravity and collects on the bottom of the tank 2, while the released air must be constantly transferred outside by the vacuum cleaner V to maintain the predetermined value of depression.

To make the above-mentioned water-air emulsion, provision has been made for the installation of an injector 1 introduced below the lower end of the riser A and which penetrates inside this column up to a height h3 slightly greater than the dimension h of the water level of the supply basin B. Through the injector I, which is placed in communication with the external atmosphere by a pipe 3, the air at atmospheric pressure flows in, according to the quantity and with the desired speed, inside the riser A in the desired proportion, by emulsifying the water contained in the latter and which is at a pressure below ambient pressure. (atmospheric).

The installation which is the subject of the present invention is completed by a downcomer C constituted by a pipe 4 in communication with the bottom of the vacuum chamber S, through which the water which has collected in the tank 2 is conveyed outside, in the harvesting basin D subjected to atmospheric pressure, to a dimension h4 (greater than the dimension h of the supply basin, but less than the dimension h2 of the vacuum chamber) established at a height immediately lower than the height at which the water column which overcomes it can overcome, depending on the own hydrostatic pressure and that existing in the chamber S above its body of water, atmospheric pressure.

The end of the downcomer C is hydraulically closed as can be seen in the drawing.

It should be noted here that if the vacuum cleaner V, intended to create and maintain the desired vacuum in the chamber S, can be constituted by one of the many suitable mechanical devices which are found on the market, it can also be formed , for example, by a Venturi pipe in which the water necessary to obtain and maintain the desired vacuum is flowed from upstream to downstream of the available jump, or even, when the ambient conditions are favorable, by a rotor eolic connected directly to the vacuum chamber.

During operation, once the vacuum cleaner V is started, the pressure drops in the chamber S below atmospheric pressure.

Consequently, the water contained in the supply basin B tends to rise in the rising column A to a height corresponding to the difference, in meters, between the atmospheric pressure and the pressure existing in the rising column above the liquid body of water. In addition, as at any point of the riser A above the dimension h the liquid contained therein is in depression, the air at atmospheric pressure can flow through the injector I in the column riser A. The air, by flowing through the injector I in the riser in the desired proportion, mixes with the liquid and reduces its density, thus allowing the raising of the emulsion to a height higher than that at which the atmospheric pressure could have raised, compared to the depression existing in the chamber S, the only column of liquid. The riser of the siphon opens into the interior of the chamber S at a height hl greater than the height h2 of the bottom of the tank, but less than the maximum height at which the atmospheric pressure is able to lift, _{as a} function of the depression existing in chamber S, the mixture contained in the riser A. Inside this chamber S as already mentioned, the air separates from the emulsion and the residual water can flow into the use basin D, through the downcomer C, at a level h4 established at a height immediately lower than the height at which the column of liquid which overcomes it can overcome atmospheric pressure, while the air separated from the water in the tank 2 is discharged outside by the vacuum cleaner V to keep the expected vacuum constant in room S.

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Example

On the basis of what has been said above and if we take the hypothesis of lifting at 5.50 m in height 8 liters of water per second, the installation - purely as an example - could be as follows:

RISING COLUMN A

DEPRESSION CHAMBER OR SEPARATOR TANK

DESCENDING COLUMN C

VACUUM V

- any type of vacuum pump provided that it is capable of ensuring 0.2 atm. as an operating vacuum inside the vacuum chamber S or separator tank.

INJECTOR I

The injector opens inside the riser A at 1.33 m above the level of the water level of the liquid to be lifted. A 30 mm diameter pipe connects the injector to the atmospheric air intake.

A valve was provided to allow the amount of air to be supplied to the riser A to be adjusted.

QUANTITY OF AIR INSUFFLE

This quantity is regulated by the valve of the injector I. The quantity of air constituting the emulsion must not, in any case, be less than 50% of the volume of water contained in the riser A. The speed of lift can be increased by appropriately increasing the amount of air supplied.

The present invention is not limited to the example described, but includes any possible variant of execution.

Claims (9)

1. Foam trap for lifting a liquid from a supply basin located at a lower level to a use basin located at an upper level, comprising: a riser formed by a first pipe, the two ends of which are open and the lower end plunges into a supply basin; a sealed vacuum chamber inside which penetrates the upper end of the riser; a suction device capable of creating a depression in this chamber; a downcomer formed by a second pipe in communication with the bottom of the vacuum chamber, the lower end of which plunges into the basin of use; an injector in communication with the ambient atmosphere located inside the lower part of the riser, the outlet of which is at a higher level than that of the water body of the liquid contained in the basin supply, which sends air at ambient pressure to the riser so as to reduce the density of the liquid therein by emulsion thereof, allowing the liquid-air emulsion to rise in the riser '' to the vacuum chamber in which the separation takes place by gravity air liquid; the liquid therefore flows into the basin of use while the air is discharged outside by the suction device. 2. Foam trap as described in claim 1., wherein the depth of immersion of the lower end of the riser in the supply basin is of very low value. 3. Foam trap as described in the claims 1. and 2. whose upper end of the riser enters the vacuum chamber to a height such that the open end of the riser is at a higher level than the bottom of the vacuum chamber, but lower than the maximum level at which the ambient pressure could raise - depending on the vacuum determined and maintained in the vacuum chamber - the liquid-air emulsion contained in the riser. 4. Foam trap as described in the claims 1., 2. and 3. in which the dimension of the water level of the basin of use is established, relative to the dimension of the bottom of the vacuum chamber, so that it is immediately lower than that at which the column of liquid which surmounts it can overcome, depending on its own hydrostatic pressure and that existing in the vacuum chamber, the ambient atmospheric pressure. 5. Foam trap as indicated in the preceding claims in which the liquid used is water. 6. foam concentrate as indicated in the preceding claims wherein the ambient pressure is atmospheric pressure. 7. Foam trap as described above with reference to the single drawing attached.

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