JPS6036801B2 - High-speed liquid scooping device - Google Patents

Description

[Detailed Description of the Invention] The present invention is an apparatus for scooping liquid on the surface of the liquid to be scooped at a high relative speed between the scooping mechanism and the surface of the liquid, which is more effective than conventional products. This invention relates to an improved scooping device capable of scooping.

Various devices are already known that scoop and collect liquid at high relative speeds, such as water tanks onboard aircraft for spraying crops, firefighting, and especially for forest fires. Some fly over the surface of nearby lakes or rivers, scooping up water and refilling it mid-flight.

Such devices are described, for example, in U.S. Pat. The former includes a scooping device,
The device is retractable to allow the aircraft to land or splash down on the water, and when the device is inserted to a significant depth (greater than 10 mm) to scoop water while the aircraft is flying sufficiently low, the aircraft A type that is held securely and rigidly against the body is described. The latter patent also describes a version in which the scooping device is submerged by means of a small wing surface that is capable of penetrating into the water. The range of applications for high relative velocity liquid collection devices is not limited only to flat surfaces such as water surfaces, but also includes pumps and centrifuges in which a liquid annulus with a free continuous inner surface is formed.

Similarly known is a fixed scooping mechanism. This is a form of immersion into a rapidly moving liquid, such as running water or a liquid annulus in a centrifuge, and the use of the kinetic energy of the liquid to eject or place the liquid under pressure. belongs to. Regarding this point, 1
U.S. Patent No. 2,124,91 granted July 26, 1993
No. 4 can be cited. This patent describes a centrifugal separator in which the liquid annulus impinges on a skimming device projecting from the liquid surface of a skid which is placed on the free surface of the internal liquid annulus. There is. Broadly similar are French Patent No. 1,368,864, filed June 25, 1963, and British Patent No. 987,023, published March 24, 1963. In these prior art techniques, the scooping orifice is immersed into the liquid to be collected, which presents several difficulties. That is, the relative movement between the liquid and the scooping device acts to force the scooping device deeper into the liquid, such as a spatula, for example. This is not only a disadvantage when only a surface portion of the liquid needs to be skimmed, as in the case of centrifuges, but also the hydrodynamic drag and mechanical forces on the support and attachment means of the skimming device. Significantly increases stress. Furthermore, there are unavoidable variations in the relative spacing of the mechanism and the liquid level, such that air and liquid sometimes meet, then are drawn in, and sometimes are drawn in simultaneously. It is also important to keep in mind that the load may not be applied uniformly and the load may vary, causing fatigue. The aim of the invention is to overcome the above-mentioned problems and also to meet the following requirements in certain industries, especially in the field of ultracentrifuges: low power consumption, no disturbance of the general flow, excessive mechanical The aim is to satisfy the following requirements: no vibration and no cavitation.

According to the present invention, the above object is to automatically maintain the position of the device even if the relative spacing between the device and the liquid surface changes due to the relative speed between the device and the liquid surface or other working parameters. This is achieved by providing a liquid skimming mechanism that is regulated to ensure maximum efficiency and minimize hydrodynamic drag.

In contrast to the devices of the prior art, the device of the invention has no parts that are submerged in the liquid, causing excessive drag forces and thus high energy consumption.

This device works through the action of a skim orifice formed to align with the liquid surface of a liquid lift-generating skid that operates much like a water ski to maintain the skim orifice at the liquid level. The skid is then pressed by a restoring force, such as gravity, a spring, a jack, etc., towards the liquid surface, ie in a direction opposite to the liquid lifting force generated by the skid. The scooping conduit is
On the side remote from the liquid level, without any protrusions or constrictions, it connects to the orifice, preferably at a slightly acute angle to the orifice.

Such a conduit may have a circular or rectangular section, and the orifice is preferably formed at the intersection of the conduit with the rear liquid level of the skid. In conventional immersion type scooping devices, immersion is absolutely necessary because scooping is performed by diverting the velocity of the fluid with an obstacle.

In the present invention, on the contrary, when the skid is installed at a certain angle of incidence, pressure (lift) is generated below the surface of the skid. If there is a perfect fit between the surfaces of the two skids, a flow will occur in response to the pressure difference. The fundamental advantage of the device according to the invention is due to the above-mentioned features, as it turns out that the hydrodynamic drag is very significantly reduced, the main reason being that the cavitation phenomenon is almost completely eliminated. This is because it disappears.

This cavitation phenomenon occurs when the local static pressure becomes lower than the saturated water vapor pressure of the liquid.

The actuation of the skid creates a large static pressure that retards the creation of this phenomenon. In particular, by locating the skimming orifice close to the point of contact between the front of the skid and the fluid, the local static pressure is very close to the total pressure (which is extremely high in centrifuges), thereby reducing the risk of cavitation. will disappear. Such positioning can be achieved by adjusting the force with which the skid is pushed towards the liquid level. Moreover, in such cases the maximum degree of skimming is achieved. It will become clear how the invention may be practiced from the following description, taken with reference to the accompanying non-limiting, illustrative drawings, in which: FIG.

In FIGS. 1 and 2, it is assumed that the liquid L has a flat surface S. In FIGS.

Arrow F indicates the direction of relative movement. The skimming device shown here has a skimming orifice 1 formed in the surface of the skid 4, preferably terminating in a front end 5, similar to that of a water ski. In the embodiment shown in FIG. 1, scooping orifice 1 and skid 4
means an arm 6 pivoting on a support 7 about a hollow horizontal axis 8
The rod 8 is connected on the one hand to the orifice 1 via an internal passage 9 and on the other hand to a tank (not shown) via an external conduit 10. There is.

An extension 11 is fastened to the arm 6 and is connected to the support 7 via a tension spring 12, which tends to pivot the arm 6 clockwise. In other words, this spring serves to immerse the orifice in the liquid L. The effect of this spring action is assisted by the moment generated by the weight of the skid. This spring device is
It may be omitted if the skid has sufficient weight. Pivoting is limited in both directions by adjustable stops 13 and 14 on the support 7. These stops are made, for example, by nipples screwed into the support 7 and locked to the support with locking nuts.
The operation of the device shown involves relative motion, which may be at high speeds, in which the device is fixed (in which case the liquid is
There are cases in which the liquid must flow in the direction F) and cases in which the liquid is immobile (the device must then move in the direction opposite to F).

In such a case, the skid 4 will act like a hydrofoil, or in other words a water ski, by raising the arm 6 and using gravity and/or the force of the spring 12 and/or the skid 4 at the scooping orifice. generates a lifting force that balances the opposing moment generated by the drag force applied to the It should be noted that the "pull" of the mechanism described above is negligible and therefore also its hydrodynamic drag is low.

Similarly, the operating position of the mechanism is automatically adjusted,
The scooping orifice remains almost aligned with the surface S even if the height of the support 7 changes or, equivalently, even if the level of the liquid L changes. You should understand. Note that S' and S'' are the layers when the support 7 is closest to the liquid level and farthest from the liquid level, respectively. In the former case, the skid 4 moves to 4' and the arm 6 In the latter case, the skid 4 moves to 4'' and the arm 6 applies to the stopper 13. During these pivots, the inclination of the skid 4 changes in either direction by an optimum value of, for example, 5 degrees.

In order to maintain this inclination steadily without unduly lengthening the arm 6, the arm hinge structure 8 is configured such that the arm runs along a guide installed at right angles to the liquid level S, for example. May be replaced. Alternatively, the configuration shown in FIG. 2 may be provided with auxiliary means.

That is, skid 4 is hinged at one end of a link 16 at position 15, and this link 16 is hinged to support 7 at position 17 at the other end. The pivoting of the skid 4 with respect to this link 16 is controlled by the stop 8
and limited by 19. This link is further actuated by a hydraulic/pneumatically operated jack 20. The link is hinged to the jack's slide rod at position 21, and the jack 20 provides an adjustable restoring force. Finally, the scooping orifice is connected to the tank (
(not shown). A relative change in the height of the support 7 with respect to the liquid level S causes the link 16 to pivot, while the skid 4 approximately maintains its own angle of inclination.

This applies almost equally even if the liquid surface S is not extremely flat and slightly undulating. When the liquid level is slightly undulating, the skid 4 swings around its hinge 15 as it follows the waves. The configuration of this embodiment is particularly suitable for skimming water by high-speed boats, and is also suitable for practical use (for spraying on crops) and for pollution removal (for spraying on crops).
Suitable for areas with floating oil. However, implementation of the invention is by no means limited to horizontal liquid levels.

3 and 4 show an example of an application to a pump or centrifuge in which a liquid ring L is formed against a cylindrical wall C rotating at a high speed V. FIGS. According to the invention, liquid is skimmed on the free cylindrical surface S, of the liquid ring by two arms 6 similar to those shown in FIG.

These arms have radial extensions 23 on the hub 24.
It is hinged to the hub 24 and is acted upon by a compression spring 25 acting against a projection 26 of the hub 24. In FIGS. 3 and 4, cities and villages similar to those in FIG. 1 are given the same reference numerals, so a detailed description thereof is unnecessary. but,
The device shown in Figure 1 is of the type that is mounted by a hinge and tilts forward, that is, in the direction opposite to the relative movement F of the liquid, in which case the drag of the skid causes an excessive support force. In contrast, the device shown in FIGS. 3 and 4 has a hinged arm 6 that is inclined rearwards, ie in the direction of the relative movement V of the liquid.

Instead of two skids 4 placed at 180 degrees with respect to each other, a larger number of skids 4 (e.g. three spaced 120 degrees apart) can be provided and, as shown in FIG. It is clear that it is also possible to employ a hinge arrangement of the type shown in . In FIG. 5, members similar to those in FIG. 2 are given the same reference numerals, except that the jack 20 in FIG. 2 is replaced with a compression spring 25 in FIG. There is. All other effects listed for self-adjustment of the position of the skid 4 on the free surface S are obtained analogously.

A scooping conduit having a diameter of ○ (Fig. 6) and having an axis inclined at 20 degrees with respect to the rear liquid contact surface 4a of the skid 4 located behind the orifice of the scooping conduit. Particularly good results are obtained by using a conduit which closes in alignment with and in its plane of symmetry, and by adopting the following conditions: the width of the fluid filling part 4a of the skid 4, in any case, is equal to 3D. , in any case less than 8D; the length of this fluid reinforcement part 4a is less than or equal to 10D; the length of the free front part 4b is equal to 5D to 10D.

The skid operates at an angle of incidence of approximately 5 degrees, which is the angle of attack that the bag liquid level 4a makes with respect to the free surface S of the liquid.

The liquid contact surface 4a may be flat to facilitate processing.
This may be done similarly in the case of a liquid annular body. The outlet passage 9 is designed in such a way as to minimize pressure losses and, by means of a flared section 27 placed as close as possible to the intake orifice 1, it is possible in particular to reduce the velocity of the intake flow. It is.

FIG. 7 shows that in order to apply liquid to the skid 4, for example, the spring 12 of FIG. This shows a pattern of changes in the degree of incorporation depending on the degree of applied force.

The maximum intake degree M is determined by the point P in the immediate vicinity of the intake orifice. Obtained when Beyond this point, uptake decreases and drag increases. This yields important practical results.

That is, according to the present invention, it is necessary to automatically maintain the pressing force by restoring force. This is because it is practically impossible to accurately know in advance what position the skid 4 will occupy with respect to the liquid level S. Furthermore, in the case of centrifuges (see Figures 3 and 4 or 5), it is generally not possible to control the degree to which liquid enters the chamber and forms a liquid annulus therein. Probably.

This is because the thickness of this annulus increases as the intake flow becomes somewhat excessive, resulting in a downward curve in the graph of Figure 7 if the skid is located at a fixed angle. As a result, the intake is reduced and the instability is increased due to the slowdown of the D-device due to the increased drag. In contrast, a steady state is obtained in the ascending curve on the left side of the curve.

However, in practice this section is too short to be of practical use, and furthermore, it reflects a small intake of air through the orifice, which is clearly detrimental. It goes without saying that modifications and substitutions may be made to the embodiments described above without departing from the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a diagrammatic view, partially in section, of an embodiment of the invention. FIG. 2 is a similar diagram of another embodiment. FIG. 3 is a partial vertical sectional view of a liquid toroidal centrifuge which is one embodiment of the improved device according to the present invention. FIG. 4 is a cross-sectional view taken along line N-W in FIG. 3. FIG. 5 is a diagram similar to FIG. 4, showing an alternative embodiment. FIG. 6 is an enlarged diagrammatic sectional view of a skid devised for scooping up liquid. FIG. 7 is a graph showing the degree of liquid uptake plotted against the depth of immersion of the skid into the liquid. Explanation of symbols, L...Liquid, S...
...Liquid surface, F...arrow, 1...orifice,
4... Skid, 4a... Rear liquid contact surface, 5... Front end, 6
...Arm, 7...Support, 8...Horizontal axis, 9
...Internal passage, 10...External conduit, 11.
... Extension part, 12 ... Spring, 13, 14
...Stotsu/gu, 16...Link, 1
8, 19... Stopper, 20... Jacket, 22... Portable hose, L,... Liquid annular body, C... Cylindrical wall, 23... Extension body, 24... Huff, S. ...
...Cylindrical surface, 25...Compression splash, 26.
...Protrusion, D...Diameter, 27...Further end, M...Maximum intake degree. F'G. ．．・7 F/G. '3 〃G.・2 'ZG-・KUF. '5 Ordinary C. 6'XG. ．． ·a

Claims (1)

[Scope of Claims] 1. An arm designed to press a skid for generating liquid lift force against the liquid surface with a force opposing this liquid lift force and to keep this skid in a state emerging from the liquid surface. A device for scooping liquid at high speed through a scooping conduit having an orifice formed in the wetted surface of the skid supported by a flexible end, the orifice being aligned with the wetted surface of the skid. and extends,
In addition, the scooping conduit is approximately 20 m
A high-speed liquid scooping device characterized by forming a degree angle. 2. Claim 1, characterized in that the conduit is provided with a diverging portion following the orifice.
Equipment described in Section. 3 the skid is hinged to the flexible end of the arm and similarly maintains the orientation of the skimming conduit with respect to the liquid surface substantially constant regardless of relative movement of the liquid surface and/or the arm; A device according to any one of claims 1 and 2, characterized in that: 4. The portion of the liquid contact surface of the skid that extends behind the orifice aligned with the liquid contact surface and in the plane of symmetry of the liquid contact surface has a width less than eight times the width of the orifice. 4. Device according to any one of claims 1 to 3, characterized in that it has a width preferably equal to three times and/or a length less than ten times the width of the orifice. 5. The device according to any one of claims 1 to 4, wherein the liquid contacting surface of the skid adjacent to the orifice is flat. 6. Apparatus according to any one of claims 1 to 5, characterized in that the scooping conduit is embedded within the thickness of the skid. 7. The pressing force applied by the arm is adjustable, thereby changing the degree and/or pressure with which the liquid is scooped in. The device described in any of the above. 8. The device according to any one of claims 1 to 7, which is used for scooping up substances floating on the surface, such as oil, caused by aircraft or other boats sailing above the water surface at high speed. 9. A device according to any one of claims 1 to 7, which is used for skimming the surface of a liquid that is centrifuged inside a hollow rotor, such as a centrifuge or a pump. 10. The same device for use in the application according to claim 9, characterized in that the device is mounted symmetrically with at least one other similar device inside the rotor of a liquid centrifuge. Equipment described in Section.