MXPA96003565A - Double helical pump perfect, particularly suitable for pumping bifasic fluids in a underwater submar - Google Patents

Abstract

The present invention relates to double-helix pump, comprising: a suction pipe to receive a main stream of fluid, a horizontal current divider connected to the suction pipe that divides the main stream of fluid received by the suction pipe within a first and a second stream after the fluid stream enters the suction pipe, a box enclosing a pumping chamber, wherein the pumping chamber includes a first and a second pair of screws rotatably mounted and vertically, each screw of each pair of screws includes threads that interlock the two screws of each pair of screws, each screw includes an axis that extends axially through each screw, where the axes of the first pair of screws are connected with each other. -axially in series with the axes of the second pair of screws in the center of the pumping chamber, forming vertical axes that connect the first and second pairs of screws and in which the screws can be rotated in synchronism in such a way that each pair of screws propels towards the center of the pumping chamber any fluid supplied to the first or the second pairs of screws; which rotates the screws in synchrony, a horizontal current to the pumping chamber in such a way that the first fluid stream is fed to the first pair of screws, a second feed nozzle that connects the horizontal current divider to the pumping chamber in such a way that the second fluid stream is fed to the second pair of screws: an assortment chamber located in the center of the pumping chamber that receives the fluid propelled by the screws, the assortment chamber includes a nozzle from the which fluid leaves the pump chamber, and a liquid seal generator connected to the nozzle of the assortment chamber, where each vertical axis of the screws illos includes a radial channel connecting from the assortment chamber to a central axial channel on each axis, which connects to a plurality of radial channels extending to the ends of the screw threads in such a way that fluid can be supplied from the Liquid seal generator through the axial and radial channels to the ends of the screw threads

Description

PERFECT DOUBLE PROPELLER PUMP, PARTICULARLY SUITABLE FOR PUMPING BIPHYSICAL FLUIDS IN A SUBMARINE ENVIRONMENT The present invention relates to a double-helix pump which, by guaranteeing the feeds by suction at the two ends of the pump which are always perfectly the same in gas content, also as a seal between the screws and wall of the pump. Pumping chamber of the pump body, also in the transient pumping phase of the gas alone, ensures efficient and safe pumping of a two-phase fluid even when the pump is in a vertical position, which makes it particularly suitable for subsea applications. As it is known, a propeller pump is basically a rotary pump in which the positive mechanical movement of the fluid, in general a liquid, from the suction to the delivery, is obtained along a conical concavity created in coupling of a pair of conical screws firmly engaged with each other and with a synchronized movement, the seal between the teeth of the two screws and the wall of the pump chamber of the pump body is secured by a film of the centrifuged liquid itself. In order to balance the thrusts created by the movement of the fluid, according to a preferential modality of the technique, the so-called "double helix pump" is used, that is, a pump, with a double pair of synchronized conical screws connected or coaxially connected in series with each other and equipped with opposed propellers. In this pump, in fact, the simple suction is subdivided, inside the pump body, in two feeds of the opposite ends of the pump and consequently, due to the opposite screw threads of the two pairs of screws, there are two inlet currents. fluid, in opposite directions, towards the central zone or the supply zone of the pump, which create a balance in the force of the axial thrust. This type of pump is generally used horizontally, this is with the axis of symmetry of the pump arranged horizontally, and has a high efficiency, which increases with the constructive precision and assembly of the pump. On the other hand, this known pump, in the pumping of liquids, can also be used vertically, which, as is known, is the best and most appropriate position for an underwater installation of a pump. At present, however, there is a great demand for a pump which is capable of operating efficiently with biphasic mixtures of liquid and gas, for use on the sea floor, for the direct pumping of oil wells found in the continental shelf, without the help of expensive platforms. This double-helix pump is already intrinsically capable of pumping not only liquids but also biphasic mixtures of liquid and gas. In this particular application, however, it can inevitably only be positioned horizontally since a vertical position would create a different division of the mixture and the liquid, due to gravity, would settle at the lower feed end of the pump and the Gas on the other hand would settle at the upper feed end of the pump, with the result that the upper pair of propellers, in contact only with the gas and consequently not cooled by the liquid, would overheat and compress. In addition, the above known pump, also in a horizontal position, can not function in any way in the presence of gas alone, as often happens in oil wells, since the absence of a liquid phase which, as already mentioned, determines the liquid film seal centrifuged, predisposes the seal itself in correspondence with the propellers and the pump is deactivated and stops working. Attempts have been made to overcome this latter disadvantage with the use of tricks such as providing delivery of the pump with a liquid seal generator of the liquid phase which accumulates the liquid to be used to maintain or create a liquid seal., but even this solution has not completely solved the problem in the presence of fractions of very high vacuum, fraction of vacuum means the relationship between the amount of gas present in the mixture and the amount of mixture aspirated. The object of the present invention is to overcome the above disadvantages and consequently to provide a propeller pump, of the double helix type, which works perfectly in a vertical position, in the two-phase field of the gas-liquid mixtures, even in the absence of a liquid phase. This is basically achieved by the fact that the two feed. opposite ends, top and bottom, of the pump or feedthroughs, is carried out separately by means of a current divider placed between the simple suction pipe and the feedthroughs and by the fact that the propeller shafts are equipped with a central axial perforation which joins between them and the supply mouth of the pump, a series of radial channels which end on the tips of the individual teeth. This in effect ensures that the two pump supply ports are always supplied with quantities of fluid which are perfectly equal in gas content, even when the pump is in a vertical position, and that a minimum amount of liquid stored in the pump liquid seal generator of the liquid phase, located in the delivery mouth, driven by the supply pressure inside the central drilling and channels, creates an effective liquid seal which also allows the pumping of the gas phase alone. In short, the double-helix pump, which comprises a fluid suction pipe which is connected to two fluid supply ports placed respectively on the two ends of a twin pair of conical screws, the screws of each pair are interfused and its axes are joined coaxially in series with those of the other pair, where the screws rotate in synchronism, by means of a motor, inside the pumping chamber and the propeller of one pair is opposite that of the other pair to transport the currents from the feed mouths to the center of the pumping chamber where there is a supply chamber whose mouth is connected to a liquid seal generator of the liquid phase, is characterized, according to the present invention, by the fact that the twin pair of conical screws is in an upright position, the fluid suction pipe is connected to the two fluid feed ports, with separate pipes, by means of a crossover and each of the two axes of the twin pair of conical screws is equipped with a central axial bore that connects between them and the supply chamber a series of radial channels which end at the tips of the individual teeth of the conical screws. According to a preferred embodiment of the present invention, the current divider consists of a horizontal expansion / separation cylinder, attached on one side to the suction pipe and longitudinally equipped, halfway, with a vertical internal dividing wall to create two equal chambers, which are respectively connected, on the other side of the barrel, to the two mouths for feeding the fluid in the pump. In this way, in fact, the separation takes place in the cylinder of the two phases of the biphasic mixture supplied by the suction pipe, the gas sits in the upper part of the cylinder and the liquid settles in the lower; on the other hand, the dividing wall perfectly subdivides the mixture into two equal parts, in order to guarantee that the feed nipples of the pump are fed with an equal composition of the fluid, even if it is arranged at different heights. The invention can be better explained with reference to the accompanying drawings which describe a preferred practical embodiment which is only illustrative and not limiting since technical or constructive variations can be applied, which still remain within the scope of the present invention. In these drawings: Figure 1 shows a front, sectional, partial view of a double-helix pump according to the invention; Figure 2 is a side sectional view of the current divider according to the invention, according to line AA of Figure 1. With reference to the figures, the number 1 indicates the body of the vertical pump, basically in the shape of Cylindrical, which is closed at the bottom by the tank 2 for lubricating oil and on the top by the electric motor 3, with a reducer, possible. The motor 3 makes the twin pair of conical screws 4 and 5, respectively, arranged vertically, rotate inside a pumping chamber 6 which is also vertical and edged by the cylindrical wall 7 arranged coaxially to the interior of the body 1 of the pump. The conical screws 8 and 9 of the upper pair of screws 4 are interfused and their axes 10 and 11 are coaxially connected in series with the corresponding axes 12 and 13 of the other lower pair of screws 5, whose conical screws 14 and 15 are also interfused . The propeller of the upper pair of screws 4 is opposite to that of the lower pair of screws 5 with the purpose, as can be seen clearly in Figure 1, of transporting the currents, from the upper end of the pumping chamber or feed mouth upper 16 and from the lower end or lower feed mouth 17 respectively, towards the center 18 of the pump chamber 6. This center 18 communicates, by means of the inlets 19 and 20 located in the cylindrical wall 7, with a chamber delivery 21 whose supply mouth 22, located in the body of the pump 1, is connected, by means of the pipe 23, to a liquid seal generator of the liquid phase 24. This generator 24 is basically an upper deflector tube of the stream 25, which maintains a liquid seal 27 on the bottom 26. Then the supply chamber 21 describes, between the body of the pump 1 and the external wall of the pumping chamber 6, an upper chamber 28 communicating with the mouth of food n upper 16 and a lower chamber 29 communicating with the lower feed mouth 17. The chamber 28 communicates with the chamber 32, by means of the inlet 30 located in the body 1 of the pump and the pipe 31, a divider of stream 33, which consists of a horizontal expansion / separation cylinder 34 attached to the suction pipe 35. The horizontal cylinder 34 is internally equipped, midway, with a longitudinal divider wall 36 which likewise divides the chamber 32 of the chamber 37 which is attached to the chamber 29 by means of the pipe 38 and the inlet 39 located in the body 1 of the pump. Finally, the two axes 10, 12 and 11, 13 are each equipped with a central bore 40 and 41, respectively, which communicate with the center 18 and therefore with the liquid seal 27 of the generator 24, and is equipped with a series of radial channels 42 which end on the tip of the individual teeth of the conical screws. Having described the invention as above, the content of the following is claimed as property:

Claims (2)

1. A double-helix pump, comprising a fluid suction pipe which is connected to two fluid supply ports, placed respectively on the two ends of a twin pair of conical screws, the screws of each pair are interfused and their axes they are coaxially connected in series with those of the other pair, where the screws rotate in synchronism, by means of a motor, inside a pumping chamber and the propeller of one pair is opposite to that of the other pair to transport the currents from the supply ports to the center of the pumping chamber where there is a supply chamber whose mouth is connected to a liquid seal generator of the liquid phase, characterized in that the twin pair of conical screws is in a vertical position, the pipe of fluid suction is connected to the two fluid supply ports, with separate pipes, by means of a current divider and each of the two axes, twin screw torque The conical cone is equipped with a central axial perforation that connects a series of radial channels between them and the supply chamber which end on the tips of the individual teeth of the conical screws.

2. The double-helix pump according to claim 1, characterized in that the current divider consists of a horizontal expansion / separation cylinder, connected or attached on one side to the suction pipe and longitudinally equipped, halfway, with a wall vertical internal divider that creates two equal chambers which are respectively connected, on the other side of the cylinder, to the two mouths of fluid supply in the pump. iartr * ctP Bomb doubles the war, and the four conical battles are divided vertically and are fed with biphasic fluid at both ends, independently of each other, by means of a current divider and where the two axes of double warfare each have an axial central blade which connects the delivery chamber to a series of radiating channels which terminate on the apex of the line of propellers. A preferential current divider is described.