Device for creating and exploiting a pressure difference and a technical application thereof.

(74) Agent

Paul Werner Straub, Schlosslistr. 2, CH-3202 Women's Chapels, CH John Herman Stark, Wattenwil, CH

Michel Vermot, Vinelz, CH

Paul Werner Straub, Women's Chapels, CH

Gunnar O. Reistad, Bryns Patentkontor AS, Oslo (54) Designation Device for providing and utilizing a pressure difference, consisting of one of two coaxially opposed hollow cone pieces formed with its smaller base surfaces (56) Published publications DE 829648, FR 740179, FR 1310598, US 2080624 (57) Abstract

A new method is provided for providing a pressure difference in a flowing medium, a device for carrying out the method and a variety of technical applications. The flowing medium, which may be a liquid or a gas, is passed along the longitudinal axis of a double cone, which double cone consists of two with the smallest base surfaces coaxial to each other's right hollow cone pieces. At the narrowest point in the double cone, a negative pressure occurs in the flowing medium. This can be made available outwardly through a side connection socket. Compared to the similarly operating venturi tubes, the double cone of the invention has a much higher efficiency thanks to the special shape defined by certain geometric conditions. The high efficiency of the double cone, which can be further increased by a particular embodiment, makes the process of the invention suitable for a variety of technical applications.

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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for providing and utilizing a pressure differential consisting of one double cone formed coaxially opposed hollow cone bumps, the double cone being enclosed by a hollow cylinder having a lateral connecting bush in the casing surface.

The device according to the invention is based on the use of a modified venturi tube. This nearly 200-year-old, known device is in its form a rotational body having a complicated asymmetric curve as a generator. The body of rotation consists of a tube which, in accordance with the curve worm, narrows asymmetrically in its longitudinal direction and then expands. If the venturi tube is flowed by a flowable medium, a negative pressure will be created inside the tube - relative to the pressure measured at the entrance and exit cross sections - with the pressure difference according to the law formulated by Bernoulli in 1680 reaching a maximum at the narrowest point in the tube.

The venturi pipe is used in several areas, for example as an instrument for measuring the flow velocity of liquids and gases in pipes, further for measuring the velocity of aircraft and ships, as a water jet pump (Fig. 2) for evacuation of containers, further in gasifiers for internal combustion engines and in devices. for gas washing.

When using the venturi tube as a measuring instrument, it is a disadvantage that the pressure difference read at the measuring points does not depend on the flow rate in a simple calculable way. Several other factors, such as, for example, the viscosity and density of the flowing medium, the height of the input and output pressures and, not least, the exact geometry of the nozzle shape and wall roughness, are decisive factors in determining the measurement result, so that in practice for each defined measurement task it must be provided. one just within the narrow boundaries of the current adjustment curve. Certain simplifications and norms of the nozzle shape (fig. 3) has admittedly led to improvements and enabled a better reproducibility of the measurement results, while the relationship between flow velocity and measured pressure difference is still complicated even by the standardized venturi model.

It has now been found that surprisingly, and from hitherto known, non-deductible benefits can be obtained by replacing the usual venturi tube form with a double cone as shown in FIG. 5a, whose geometric conditions satisfy the following conditions:

F = (1 + sin's Eye)² . its²0₂ in 0.02,

1° &lt; 0! &lt; 10’ , 1’ &lt; 0₂ &lt; 10°,

0.001 d &lt;h &lt;20 dd &lt;D &lt;200 d where

0 · ^ is the opening cone opening angle

Increase is the opening cone opening angle

F is the above function d is the diameter of the smaller of the opposing hollow jug stumps

D is the largest diameter of the two cone stumps, and h is the free distance between the two hollow cone stumps, in addition, the inner diameter T of the hollow cylinder must lie between 1, 5d and 100d and the width S of the connecting bush is between 0.001d and 10d, and the distance h is one-sided pruning of the output hollow cone stump in such a way that the smaller base surface of diameter d at the entrance hollow cone coincides with the intended cutting plane of the two hollow cones; and the tip of the exit hole cone is shortened by the stretch h so that the smallest diameter of the exit hole cone at the pruning is increased to the value

D₂ - dd₂ = d + h. (------------------)

L₂ + h since here dg is the smallest diameter in the output cone, Dg ^isthe largest diameter and Lg is its length.

In itself, a device for utilizing a pressure differential and consisting of a slender double cone is known from US 2,080,624. A double cone shown schematically in its simplest form in FIG. 4, not only allows for easier viewing and calculation of the hydrodynamic conditions and a better consistency of measured and calculated data within a broad range¹⁰ area, but also surprisingly enables a significantly higher efficiency. That is, for a given flow rate for the flowing medium, a higher pressure difference has been found between the input cross section and the narrowest location in the double cone. This higher pressure difference means a better one¹⁵ suction effect at the same inlet pressure. In contrast, the total flow resistance of the double cone at a given flow rate of medium is determined by the pressure difference between the total double cone input and output cross sections. This is decisive for the efficiency, ie for the ratio of the pressure to the suction effect, as shown for example in Table 2 below.

This efficiency can be partially estimated from 1 from the numerical value of the function F. The lower this numerical value 25 is below the above-mentioned limit value of 0.02, the higher the efficiency of the double cone will be. However, it also depends on the length of the input and output cones.

The high efficiency is particularly applicable at low axial flow rates, ie under conditions where the known devices experience experience losing their effect. Referring to FIG. 4, where the double cone according to the invention is shown schematically, values ​​for function F for some selected configurations are shown in Table 1 below.

Table 1: F = (1 + sin Θχ)² . its₂ 0₂

Quality factor for the double cone for different opening angles for the input and output cones respectively.

<td rowspan="2">Entrance cone angle θι</td><td colspan="5">Output cone angle θ₂</td>

<td> 1</td><td> 2</td><td> 6</td><td> 10</td><td> 15</td>

<td> 1</td><td> 0,0003</td><td> 0,0028</td><td> 0,0113</td><td> 0,0312</td><td> 0,0693</td>

<td> 3</td><td> 0,0003</td><td> 0,0030</td><td> 0,0121</td><td> 0,0334</td><td> 0,0742</td>

<td> 6</td><td> 0,0004</td><td> 0,0033</td><td> 0,0133</td><td> 0,0368</td><td> 0,0817</td>

<td> 10</td><td> 0,0004</td><td> 0,0038</td><td> 0,0151</td><td> 0,0415</td><td> 0,0923</td>

<td> 15</td><td> 0,0005</td><td> 0,0043</td><td> 0,0173</td><td> 0,0478</td><td> 0,1061</td>

Table 1 shows that the value of the function F responds much more strongly to the magnitude of the starting angle than to the ²⁰ the size of the input angle: as long as the output angle is small enough, good results can also be obtained with relatively large input angles. The table shows that the opening angle, at least on the exit side, must not exceed 10 °. For the classification of the quality of a double cone according to the invention, the following approximate directional values ​​apply

<td>Function F &lt;0.0035</td><td></td><td>excellent</td>

<td> 0,035 -</td><td> 0,0155</td><td>very good</td>

<td> 30 0,0155 -</td><td> 0,0250</td><td>good</td>

<td> 0,0250 -</td><td> 0,0500</td><td>satisfactory</td>

<td> 0,0500 -</td><td> 0,1100</td><td>hardly adequate</td>

<td> &gt;</td><td> 0,1100</td><td>unsatisfactory</td>

<td>35 With the aforementioned and</td><td>in the requirements</td><td>set restriction</td>

0.02, it is ensured that the double cone according to the invention will also satisfy high requirements. At the same time, a restriction has also been made to previously known, apparently similar facilities.

The dual cone of the invention has many applications, for example as a vacuum pump and as a pressure pump, as well as in many functions derived therefrom, for example as a regulating element. Since its efficiency as a pump is also maintained even at low input pressures and low flow rates, compared to all conventional jet pumps or ejectors, it offers significant technical advantages. In particular, it can be used, for example, for the recovery of energy from slowly flowing water.

The technical advantages of the double cone can be demonstrated in an eye-catching way, for example, based on its use as a water jet pump, in comparison to a conventional jet pump:

Table 2: Capacity comparison between a dual cone according to the invention and a conventional water jet pump.

<td rowspan="3">Water pressure at the entrance</td><td colspan="3">Dobbeltkonus</td><td colspan="3">konv.vannstrålepumpe</td>

<td rowspan="2">Vacuum it. 10 min.</td><td rowspan="2">Vann a *</td><td rowspan="2">1 / t b *</td><td rowspan="2">Vacuum it. 10 min.</td><td colspan="2">Water 1 / h</td>

<td>a *</td><td>b *</td>

<td> 300</td><td> -225</td><td> 78</td><td> 115</td><td> -105</td><td> 125</td><td> 140</td>

<td> 400</td><td> -310</td><td> 91</td><td> 123</td><td> -140</td><td> 143</td><td> 163</td>

<td> 500</td><td> -385</td><td> 104</td><td> 139</td><td> -185</td><td> 160</td><td> 183</td>

<td> 600</td><td> -450</td><td> 112</td><td> 151</td><td> -215</td><td> 176</td><td> 200</td>

<td> 700</td><td> -500</td><td> 123</td><td> 160</td><td> -250</td><td> 190</td><td> 218</td>

*) Water consumption a at the start, b at the end of the evacuation.

A further interesting feature of the double cone according to the invention is its dependence on the pressure prevailing in the system: Under identical geometric conditions and with equal fluid flow, the pressure difference between the input cross-section and the most tightly positioned side connection will be higher the higher the total pressure prevailing in the system. Likewise, the flow resistance through the double cone will also change as the flow resistance decreases with increasing pressure. This is quite surprising and was not to be expected from the known hydrodynamic theories, at least not for incompressible media.

Table 3: Symmetrical double cone, total length 140 mm.

Opening angle of the input and output cones, both 6 '.

Diameter at the narrowest point: 1.94 mm

Medium: Water at 20 ° C.

Flow at constant pressure drop of 0.600 bar:

System pressure at the entrance

Throughput 1 / min.

bar bar bar

185

225

255

A further surprising effect of the double cone according to the invention is that - at equal flow velocity - the pressure difference set between the input cross section and the narrowest point will be greater in open systems than in a closed system with forced circulation, i.e., a water flowing at a certain speed Submerged double cone will produce a higher pressure difference than an equal double cone, where at the same rate a flow is provided by a pump. In particular, this connection also applies that the double cone remains effective even at low input pressure and low flow rate, respectively.

In its simplest form (Fig. 4), the double cone consists of two hollow cone pieces connected to its smaller base surfaces 1 in the axial direction. In order to achieve a good business, the opening angle of the input and output cones respectively is chosen so that the function F According to Table 1 is given a favorable value. Suitable opening angles for the two cones are between 1 and 10 angular degrees; the ratio of the diameters at the inlet and the outlet, respectively, to the diameter of the narrowest cone, which ratio will function both by the opening angle as well as by the length of each hollow cone stump, is within the limits of 1: 1 to 1: 200.

A double cone according to FIG. 4, of course, has only a theoretical value: in order to exploit the pressure difference obtained by the flow in the double cone, one must have an opening at the narrowest point, through which the negative pressure prevailing at that location can have an effect on the surroundings.

As such an opening is suitable, for example, a circular opening with a radially directed connecting bush. However, this device will have the disadvantage of a certain asymmetry, which in particular will have an adverse effect as stronger flow enters the main axial flow through the side opening.

For the practical application, therefore, a special embodiment has been developed, which has proven to be favorable for the technical application. In particular, this embodiment allows a distribution of the inflow current entering the narrowest point symmetrically over the axial flow cross section. In this embodiment (Fig. 5), the two hollow cone pieces are separated from each other in the narrowest location, in such a way that the two smaller bases are spaced apart h. At the same time, the two hollow cone pieces are coaxially connected to a cylindrical pipe piece, which pipe piece encloses the open area and holds the two part pieces together purely mechanically. The cylindrical connecting tube has one or more radially directed connecting pins on its sheath surface. If the small diameter of the two hollow cone stumps is denoted by small d, the approximate following most favorable values ​​will be obtained for the dimensions in the area of ​​the cone nozzle:

Distance between the cone barrels

Inner diameter of the hollow cylinder

Inner diameter of the connecting pin h = 0.001 ... 20 d

T = 1.5 .... 100 d

S = 0.001 ... 10 d

It has further been found that the effect of the double cone according to the invention can be further increased with a slightly modified embodiment:

According to claim 1 (FIG. 5a), the double cone for obtaining a higher power is divided asymmetrically, starting from a double cone of FIG. 4, the total distance h between the two cone stumps is obtained by one sided pruning of the output cone: the smaller base surface of the input cone stump will then coincide with the original base surface and retain its original diameter d; the cone stump on the output sled is pruned with a stretch h; its base surface is thereby displaced a distance in the direction of flow from the input cone. The diameter of its smaller base surface is thereby increased to the value

D₂ - dd₂ = d + h. (------------------)

L₂ + h where D₂ is the largest diameter of the output cone stump and L₂is its length.

The invention and its possible technical applications will be further elucidated with reference to FIG. 1-6, without limiting the scope of the invention.

Fig. 1 shows a venturi tube in the usual embodiment

<td colspan="2" rowspan="2">FIG. 2</td><td>shows a water jet pump where the venturi pipe is</td>

<td>used,</td>

<td>FIG ·</td><td> 3</td><td>shows the standardized shape of a venture pipe ISO 15 (1983),</td>

<td>FIG.</td><td> 4</td><td>shows the basic shape of a (asymmetric) double cone),</td>

<td>FIG.</td><td> 5</td><td>shows the symmetrical embodiment of a double cone,</td>

<td>FIG.</td><td>5a</td><td>shows an improved asymmetric embodiment according to claim 1, and</td>

<td>FIG.</td><td> 6</td><td>shows an application of a double cone as a pressure pump.</td>

In the drawings, FIG. 1 is the usual form of a venturi tube¹? in longitudinal section. The flowing medium passes through the input cone 1, through the narrowest location 3 and out through the output cone 2. The lowest pressure will be obtained in the constriction 3.

²⁰ Follow. 2 shows the usual use of the venturi tube as a water jet pump. Water flows through the nozzle 4 towards the venturi tube 5. As a result of the vacuum, air or other flowable medium is sucked in at 6.

Fig. 3 shows the standardized embodiment of a venturi tube according to the standard ISO 15 (1983). The medium flows from the cylindrical input tube 7 to the input cone 8, whose cone angle is approx. 21 '. The cylindrical nozzle piece 9, whose length is approximately the same as the diameter, is, in the same manner as the input tube 7, provided with side openings 11. The flowing medium proceeds through the tapered exit tube 10, which has an opening angle of between 7.5 and 15 '. .

Fig. 4 shows the double cone according to the invention in its simplest basic form, with input cone 12 and output cone

13. The lowest pressure occurs at the constriction 14.

Fig. 5 shows an embodiment of the double cone according to the invention, as claimed in claim 9, in longitudinal section. The input cone 15 has the length, a largest diameter D 1 and an opening angle. The output cone 16 has the length L₂, a s largest diameter D₂ and an opening angle θ₂; the smallest base surfaces of the two cone stumps, both of which have a diameter d, are spaced apart from each other by a cylindrical connecting tube 17. This cylindrical tube, which has an inner diameter T, is provided with a lateral connecting bushing m 18, the inner diameter of which is S.

Fig. 5a shows an improved embodiment of the double cone according to the invention, as claimed in claim 10: The arrangement of the two hollow cone pieces is made in the same way as in fig. 5, but the original cut circle (15b) for the two cones is now offset a distance h / 2 in the countercurrent direction, and the output cone 16a is shortened by the length h. Thus, the input cone butt 15a has its original smallest diameter d | = d, while the smallest diameter of the output cone stump 16a is somewhat larger and constitutes

D₂ - dd₂ = d + h. (------------------)

L₂ + h

Fig. 6 shows the use of the double cone according to the invention as a pressure pump. By means of the turbine 23, water is pumped in circulation through the double cone 24 and the closed pressure vessel 25. In the lateral cone of the double cone, the additional flowable medium is sucked in as a result of the provided negative pressure. If air is sucked in, the pressure in the pressure vessel 25 increases while the volume of liquid remains constant. If water is sucked in instead, the pressure increases, while the air volume is reduced.

A comparison with the conventional water jet pump also shows here how superior the new device is. At the same dimensions as in the previous example, with a water pressure of 1000 mbar at the inlet of the pumping device, a final pressure 1 was reached in the pressure vessel of maximum 1000 mbar with the water jet pump, while with the new double cone more than 5000 mbar was reached, ie several times the pressure provided by the locking pump.