Rod profile for a rake a hydroelectric plant.

[0001] The invention relates to a rod profile for a rake a hydroelectric plant, and a rake for a hydroelectric plant.

[0002] Strainer Installing before the inlet of the turbines in hydroelectric plants, in order to prevent come that [...] and/or fish in the turbine. They shall be of a plurality arranged parallel to one another staff profiles. Sooner these rod sections were simple rectangles. Because these rectangles have relatively sharp edges, they have a relatively high flow resistance and fish violate, the swim against these rod sections.

[0003] There is another rod profile is hereinafter referred to as the designated [...] -profile, comprising a rounded head and a then rectangular portion. This constitute [...] -rod profile is an obvious improvement on the rectangular rod profile.

[0004] a computer system is known from the 207,326, whose rod sections have a rectangular cross-section. The rod sections are rounded and at its rear end in the direction of flow at the front in the direction of flow is formed as an isosceles triangle.

[0005] from DE purifying rakedouble computing rust for waste water with a known 3,715,020 C2 is a. A first group of approximately trapezoidal head has a rectangular cross-sectional area connects the slide rules a sn, the thickness of which is reduced with respect to the trapezoidal head. Between these staff profiles further rods are used having circular cross sections.

[0006] from DE 1,911,979 is known a two-part rod profile. The rear end part of this rod profile member is of a trapezoidal configuration and is fixedly connected with the support structure or its computing lattice. On the front part of the rod profile is produced via a dove-tailed compound on the rear part is pushed. This is the front part of the rod profile is produced in the event of a damage easily change, without discharging water power force plant the congestion or the disabled to take.

[0007] The invention is based on the problem, to provide an improved rod profile, the represents a significant improvement on the danger of injury from fish and as regards [...][...] -rod profile. At the same time the manufacturing costs are the same or only insignificantly exceeds those of the rod profile is produced according to the invention should the [...] -rod profile is produced. Furthermore, should be suppressed to the vibrations of the slide rules.

[0008] This problem is solved according to the invention for a rake a hydroelectric installation comprising a rounded head at a rod profile and an adjoining portion having a rectangular section thereby that the portion of rectangular cross-section at the rear end has an asymmetric region of reduced thickness in the direction of flow. This region of reduced thickness can as [...] trapezoid, or be constructed as an isosceles triangle or as a multi-step Rectangle unequal-leg. The asymmetric configuration prevents the generation of vibrations of the prevents slide rule very effective. If the slide rules come in vibration, decreases your lifetime in undesirable noise generation and it can come through material fatigue.

[0009] This that the thickness of the portion having a rectangular cross-section is reduced at the rear end, the oscillation is excited and, as a result ( [...]vortex trail ) replacement eddy be reduced on the slide rule is reduced significantly. The negative effects of the vibrations are thus also reduced.

[0010] If according to the invention is subjected to flow obliquely rod profile, the particularly advantageous embodiment according to the invention is of the rear end of the rod profile is produced.

[0011] It has proved to be advantageous, when the maximum thickness of the head at least 15% of an overall length of the rod profile member is spaced from the tip of the rod profile member disposed. This the thickest area of the rod profile member is laid with respect to the further rearwardly and, as a result, the tip is [...] -rod profile round and less dangerous for the fish rod profile is produced according to the invention of the. Whereas the flow resistance further improved.

[0012] It has proved to be advantageous, when the portion 60% of the total length of the rod profile member occupies less than of rectangular cross-section. Even thereby the flow resistance will be improved further according to the invention opposite a [...] -rod profile of the rod profile is produced.

[0013] Another significant improvement of the flow resistance is achieved, if the transition between the head and the portion of rectangular cross-section having a large radius is rounded. The radius greater than 15% in the region of the transition should, preferably greater than 30% and particularly preferably greater than 50% of the total length of the rod profile member be.

[0014] Additional advantages and advantageous configurations of the invention are of the following drawing, its description and the claims can be removed. All in that design, their description and the claims disclosed characteristics invention-substantially both singly and in any combination with each other can be.

[0015] It show:

Fig. staff profiles a schematic representation of a rake with the invention,

Fig. 2 different angle of attack of the rake,

Fig. 3a, an embodiment of a rod profile is produced according to the invention,

3b and 3c different implementations of the rear end of a rod profile is produced according to the invention Fig.,

Fig. flow losses compared and the different rod sections 4

Fig. [...] -rod profile 5 a comparison of the according to the invention with the rod profile is produced.

[0016] In the 1 1 arranged side by side and in parallel a plurality of according to the invention are rod sections Fig. represented. Several such parallel rod sections form a rake 1. Such forks can comprise 50 or more such rod sections cover^{an area of more than 10 m and} 2 1.

[0017] the relevant person skilled in the art are sufficiently well known Since such a rake is dispensed with to a detailed description. In connection with the invention wish to point out that the in the 1 is represented from left to right of water flows through Fig. Strainer. "X" indicated by an arrow with the flow direction is These.

[0018] One important is the inside width LW size for the interpretation of a rake, the marks the minimum distance between two adjacent staff profiles 1. A 15 mm is a good compromise between protecting clear width of the secondary losses of the rake from fish, on the one hand, and, on the other hand, represents. Therefore, as a rule is nowadays applied for in new buildings of 15 mm and an inside diameter of computing cleaners by the competent authorities also approved.

[0019] in the direction of flow X is represented in practice 1 Fig. The not always exactly parallel to a longitudinal extension of the rod sections, but sometimes the rod sections 1 are also subjected to flow obliquely. This situation is represented in the 2 Fig.. In the 2 are indicated three Arrows Fig., extend at an angle of 0° the, 15 ° and 30° to the longitudinal extent of the rod sections 1. Should the flow directions X represent Arrows These three. With the oblique incident flow the flow resistance takes to of the rake. Therefore a oblique incident flow is undesirable, but not always avoid is increasing. One is seeking, an inflow angle of 0° to realize.

[0020] 1 3 an embodiment is one according to the invention increases in the Fig. represented rod profile is produced. The is also indicated by an arrow in the direction of flow X 3 Fig.. The according to the invention has a total length L from the tip 1 rod profile to the rear end. In the 3 is located the tip of the rod profile member 1 on the left sheet edge Fig. and the rear end of the rod profile member 1 is located on the right sheet edge.

[0021] 1 in the direction of flow at its front end has a rod profile according to the invention the head 5 having a rectangular cross-section and then a portion 3. The head is as a symmetrical rounded profile-trained 3 of the rod profile is produced. The head has a portion with a maximum thickness D, 7 is spaced from the peak S by a dimension.

[0022] at least 15% of the total length is equal for the invented rod profile 7 Mass This L of the rod profile member 1st However, it is also possible that the maximum thickness of the head 3 further than 15% of the total length L of the rod profile member 1 is spaced from the tip S disposed. Between 15% and 20% have proved to be particularly suitable values It.

[0023] the head down again and subsequently in the direction of flow 3 of the according to the invention is characterised by a rod profile member 1 takes into the section 5 having a rectangular cross-section radius R over. The radius R is represented in the Fig .3a. He should be as large as possible. In particular, it is advisable, when the radius of curvature R greater than 30% and preferably greater than 15% in the region of the transition 50% of the total length L of the rod profile member 1 is greater than particularly preferred. Then two replacements are avoided and the portion of the flow in the transition between the head 3 and, as a result, the flow resistance decreases of the 5 having a rectangular cross-section 1 according to the invention rod profile is produced effectively.

[0024] an embodiment 1 according to the invention is of the 3a Fig. represented in the rod profile member, wherein the rear end of the rod profile member 1 is formed as a trapezoid. In this area is, of course, the cross-section of the rod profile member 1 not rectangular, but, for example, trapezoidal.

[0025] 3b and 3c are alternative and exemplary embodiments further Fig. Over the the rear end of the rod profile member 1 shown schematically. In the 3b the rear end than equilateral triangle formed Fig.. unequal-lateral triangle (not shown) may, however, be from a It.

[0026] In the 3c the rear end of the rod profile member 1 than stepped Rectangle Fig. is formed.

[0027] All three lead to a significant reduction in turbulence shown embodiments at the rear end of the rod profile member 1 to the oscillation is excited and thereby significantly reduce rod profile according to the invention. The benefits of the invention are particularly large Structuring the rod profile member 1, when the rod profile flows obliquely is 1.

[0028] For a specific embodiment the rod profile 60 mm and a length L of 1 can in the area of the head 3 of 8 mm have a maximum thickness D.

[0029] The area 5 having a rectangular cross-section, of the triangular connection with of the invention also in the, trapezoidal or stepped rear end of the rod profile member comprises 1, can be about 35 mm long, wherein a rectangular cross-section over a length of about 27 we actually is present and the rear end has a length of about with the trapezoidal flattening then 7 to 8 mm.

[0030] 5 in this embodiment is of rectangular cross-section portion The thickness of the 5 mm approximately. Am rearmost end the rod profile has a thickness of only about 2 mm on. Of course, it is possible, to let even acute taper at the rear end 1 the rod profile. This be again reduced vibrations in the stator of the. However, the rear end, this puts less robust.

[0031] In the once by a rod 4 are of a rake flow losses Fig. with rectangular profile which, with the so-called [...] -rod profile represented in a diagram according to the invention and with a rod profile. When infinitely wider Strainer a simulation was adopted, so that boundary effects do not occur.

[0032] 9 represents the flow losses in centimeter water column The line [cm WS] of a conventional rectangular section as a function of the blowing angle, at an approach velocity of 0.5 m/s and an inside width of 15 mm constitute.

[0033] The flow losses of a rake with a line 11, the constitute [...] -profile, while the 13 are represented by the line flow losses of the rod profile is produced according to the invention.

[0034] 9 and 11 it is clear by the comparison of the lines that the already represent a significant improvement with respect to the rectangular profile [...] -profile. Now if this compares with the invented rod profile [...] -profile, it is clear that the profile according to the invention both in the case of an inflow angle of (the line 13 see) 30° 0a angles of attack of a significantly low secondary losses has always towards, than the [...] -profile.

[0035] Now if the sets flow losses[...] -profile as reference 1 intends to find and its equal, one can compare well with this [...] -reference 1 rod profile according to the invention. This comparison is represented in the 5 Fig.. The comparison indicates that the inflow angle of 0° and at a 1 rod profile according to the invention a clear width of only about 83% of the losses of the 10 mm caused [...] -profile. The value for a clear width of 15 mm (the line 17 see in the 5 Fig.) is almost identical in which inflow angle 0°.

[0036] These means nothing other, than that both during the clear width of 10 mm and at a clear width of 15 mm the flow losses has 1 rod profile according to the invention, only about 83% of the have one having a rake equipped flow losses[...] -profile.

[0037] the more oblique the incident flow is greater the angle of attack or ever, the greater the advantages according to the invention are compared to the rod profile [...] -profile of the. At a 30° angle of attack of the rod profile according to the invention with a has more than 20% less than the inside width of 10 mm flow losses[...] -profile. For a clear width of 15 mm the benefits are even greater than 30% [...] -profile of the according to the invention.

[0038] By yearly workflow losses increases the reduced a hydroelectric installation, comprising a rake, according to the invention is equipped with a rod profile. Even if it is no more than one or two centimeters is usable height of fall, so this can lead to an increase in hydroelectric plants are of, for example, with a 0.3 to 2 m yearly work of the 0.5%. Because 1 at the same cost as the rod profile according to the invention can be made [...] -profile, increases the economic efficiency of a hydroelectric plant equipped with the invented rod profile quite significantly 1.