Throttle element for pressure reduction of a process fluid

Description

[0001] The invention relates to a throttling element for pressure reduction of a process fluid, in particular for pressure reduction in a process engineering plant, according to claim 1, and to a control valve according to the type specified in the preamble of claim 8.

[0002] In process plants, process fluid flows are fed into the process processes via control valves in process fluid lines. The process fluid flows must be adjusted according to specific control parameters, including the flow rate, in accordance with the process and operational requirements. It is also well known that process plants incorporate throttling elements for pressure reduction.

[0003] Such throttling elements are well known from the prior art and generally comprise a throttling body with several flow openings through which a process fluid flows. A throttling element of this type is disclosed, for example, in DE 10 2015 005 611 A1.

[0004] It is also known that by appropriately designing the flow openings in the throttle body, targeted control of the flow rate, pressure reduction, and cavitation is possible. Besides flow openings designed as round, square, or oblong holes with a straight or helical path along their entire length (see DE 10 2015 005 611 A1), flow openings with curved, inclined, conical, and / or edged and / or undercut inner walls are also known (see DE 10 2016 102 756 A1).

[0005] US 2007 / 0240774 A1 describes a throttle body in which the flow openings penetrating the throttle body may have a triangular or star-shaped contour.

[0006] The arrangement of a throttling element in the process plant can be carried out in a variety of ways: For example, a throttling element can be designed as a component installed in the control valve, for example by designing the valve element as a perforated cone, cf. DE 24 31 322, or by arranging a valve cage permanently installed in the control valve, which interacts with the valve element, see DE 10 2015 016 902 A1.

[0007] Alternatively, a throttling element can also be arranged directly in a process fluid line as a so-called pipe throttle, for example in the inlet or outlet area of ​​a control valve, a pump or other field device for pressure reduction.

[0008] In this context, it is also known that the noise emissions occurring during the operation of a process plant are essentially due to the sound emissions occurring when the fluid flows through the throttling elements.

[0009] The invention is based on the objective of further developing a throttling element according to the type specified in the preamble of claim 1 in such a way that the throttling element causes less noise when flowing through it.

[0010] This problem is solved by the characterizing features of claim 1 in conjunction with its preamble features.

[0011] Subclaims 2 to 7 constitute advantageous further developments of the throttle element according to the invention.

[0012] The invention is based on the finding that the contour of the flow openings has a significant influence on the noise emissions of the throttling element.

[0013] The throttling element is designed in a known manner, such that the flow openings penetrating the throttling body have a fractal contour.

[0014] For the sake of completeness, the term "fractal" will first be briefly discussed: Fractal geometry is a relatively new subfield of mathematics. It deals with geometric objects, the so-called fractals, whose properties differ fundamentally from those of "classical" geometry. The most important characteristic of fractals is self-similarity, meaning that details can be discerned at every magnification level, no matter how deeply one examines the object. In contrast, if one magnifies the edge of a "classical" object, such as a circle, it increasingly resembles a simple straight line with increasing magnification. Such objects are therefore described as smooth. With a fractal, however, one will never be able to discern a straight line, but rather ever more intricate details of the object. Hence the name "fractal," from the Latin "fractus" meaning "broken," i.e., covered with countless details.

[0015] Thus, the above formulation "having a fractal contour" is to be understood in particular as meaning that the contour of the flow opening is self-similar, i.e., that the overall contour of the flow opening is composed of smaller self-similar contours having the same shape.

[0016] Since - as experiments have shown - fractal surfaces or geometries are particularly suitable for noise reduction during pressure reduction of process fluids, the design according to the invention has the effect that the sound emissions are significantly reduced when flowing through the throttling element.

[0017] According to the invention, the fractal contours of the flow openings are formed in the form of a Koch snowflake curve. An advantage of forming the fractal contours as Koch snowflake curves is that they are easy to construct and therefore relatively inexpensive to implement in a component. Furthermore, the invention provides that the Koch snowflake curve is a curve of the 2nd to 7th iteration. As initial tests have shown, a Koch curve of the 2nd to 7th iteration already ensures the necessary self-similarity of the contour for a significant reduction in sound emission, thus eliminating the need for higher iterations, i.e., even finer resolution or a higher degree of self-similarity of the contour – which would be many times more expensive to manufacture.

[0018] Preferably, the flow openings are arranged evenly distributed across at least one outlet surface of the throttle body. The even distribution of the flow openings proves advantageous because, as tests have shown, this also contributes to a reduction in the noise level and thus to lower noise generation.

[0019] Another advantageous embodiment of the invention is characterized in that the throttle body is formed in one piece. The one-piece design of the throttle body proves advantageous because wear-prone components, such as seals between two component parts, are not present, thus enabling wear-free operation of the throttle body.

[0020] Preferably, the throttle body is manufactured layer by layer using an additive manufacturing process, in particular a laser sintering process or a laser melting process, according to which a selective material deposition process or a selective material curing process is controlled based on the predetermined geometric data of the throttle body. It is advantageous that, in addition to rapid production (eliminating the time-consuming development / production of tools / molds), complex geometries and structures can also be realized simply and cost-effectively by manufacturing the throttle body using an additive manufacturing process.

[0021] An alternative embodiment of the invention provides that the throttle body is manufactured by a casting process.

[0022] Preferably, the throttle body is manufactured from metal or a metal alloy using an additive manufacturing process or a casting process.

[0023] The invention further aims to develop a control device for a process engineering plant according to the type specified in the preamble of claim 8 in such a way that an optimized operation of the control valve with regard to sound or noise emissions is made possible.

[0024] This problem is solved by the characterizing features of claim 8 in conjunction with its preamble features.

[0025] In a known manner, the control valve comprises a valve housing with a valve inlet and a valve outlet, as well as a throttling element arranged between the valve inlet and valve outlet. According to the invention, the throttling element is now configured according to one of claims 1 to 7.

[0026] All the details relating to the throttling element according to the invention can be applied analogously to the actuator according to the invention, so that the aforementioned advantages can be achieved with it.

[0027] According to a first embodiment of the control valve according to the invention, the throttling element is designed as a valve cone that is relatively movable in relation to a housing-fixed valve seat.

[0028] An alternative second embodiment of the control valve according to the invention is characterized in that the throttling element is designed as a valve cage permanently installed in the valve housing, which in turn has a valve seat and which interacts with a valve element movably mounted in the valve housing.

[0029] Further advantages and application possibilities of the present invention will become apparent from the following description in conjunction with the exemplary embodiments shown in the drawings.

[0030] The description, claims, and drawing use the terms and associated reference numerals listed below. In the drawing, this means: Fig. 1 a sectional view of a control valve with a throttling element designed as a valve cage according to the prior art; Fig. 2 a schematic, enlarged representation of the valve cage made of Fig. 1 with flow openings designed according to the invention, and Fig. 3 an enlarged view of a flow opening made of Fig. 2 .

[0031] Fig. 1 shows a control valve designated with a total of more reference digit 100 for a process engineering plant according to the state of the art.

[0032] The control valve 100 comprises a valve housing 102 with a valve inlet 104 and a valve outlet 106, a valve element 108 which is mounted in the valve housing 102 of the control valve 100 so as to be movable in the axial direction a, and a throttle element arranged in the flow channel of the valve housing 102, i.e. between the valve inlet 104 and the valve outlet 106, which is generally referred to by reference numeral 10.

[0033] The throttle element 10 is designed here as a so-called valve cage and is fixedly arranged in the valve housing 102. How Fig. 1 As shown, the throttle element 10 is sleeve-shaped and has a plurality of through-openings 12 in its outer surface, through which a process fluid to be controlled can flow from the valve inlet 104 to the valve outlet 106. As shown, Fig. 1 It can be further seen that the through openings 12 are designed as round holes.

[0034] In the present case, the valve element 108 is guided inside the throttle element 10, which is designed as a valve cage, and accordingly, the sleeve-shaped throttle element 10 has an inner valve seat 14 that is complementary to the valve element 108.

[0035] Thus, the flow through the throttling element 10 can be adjusted via the axial position of the valve element 108 in relation to the housing-fixed valve cage.

[0036] Control valves of this type, which have a throttling element 10 designed as a valve cage, are also well known under the term "cage valve".

[0037] A known problem with such cage valves is that they tend to produce high levels of noise.

[0038] This is where the invention comes in: How Fig. 2As can be seen, in order to reduce noise emissions, it is now provided according to the invention that the flow openings 12 introduced in the throttling element 10 designed as a valve cage are designed as fractal openings, i.e. having a fractal contour.

[0039] As experiments have shown, by forming the flow openings as fractal openings, i.e. as openings having a fractal contour, the flow noise and thus the sound emissions occurring when the process fluid flows in and out of the throttling element 10 are significantly reduced.

[0040] In the present case, the throttle element 10, designed as a valve cage, is formed in one piece and is manufactured from metal or a metal alloy using an additive manufacturing process.

[0041] As especially from Fig. 3As can be seen, the fractal openings are formed in the form of a Koch snowflake curve. Forming the fractal openings in the form of Koch snowflake curves proves to be particularly advantageous, as they are easy to construct and therefore relatively inexpensive to produce, especially using an additive manufacturing process. Reference symbol list

[0042] 10 Throttle element 12 Through-openings 14 Valve seat 100 Control valve 102 Valve body 104 Valve inlet 106 Valve outlet 108 Valve element aaxial direction

Claims

1. Throttle element (10) for reducing the pressure of a process fluid, comprising a throttle body through which the process fluid flows and which has a plurality of flow openings (12), which flow openings (12) are configured to have fractal contours, with the fractal contours of the flow openings (12) being shaped like a Koch snowflake curve, characterized in that the snowflake curve is a curve of the second to seventh iteration.

2. Throttle element (10) according to any one of the preceding claims, characterized in that the flow openings (12) are evenly distributed over at least one outlet area of the throttle body.

3. Throttle element (10) according to any one of the preceding claims, characterized in that the throttle body is of a one-part design.

4. Throttle element (10) according to any one of the preceding claims, characterized in that the throttle body is manufactured in layers using an additive manufacturing process.

5. Throttle element (10) according to claim 4, characterized in that the additive manufacturing process is a laser sintering process or a laser melting process.

6. Throttle element (10) according to any one of claims 1 to 3 above, characterized in that the throttle body is manufactured using a casting process.

7. Throttle element (10) according to any one of the preceding claims, characterized in that the throttle body is made of a metallic material.

8. Control valve (100), comprising a valve housing (102) with a valve inlet (104) and a valve outlet (106) as well as a throttle element (10) arranged between said valve inlet and said valve outlet (104, 106), characterized in that the throttle element (10) is of the type specified in any one of claims 1 to 7 above.

9. Control valve (100) according to claim 8, characterized in that the throttle element (10) is in the form of a valve cone which is adapted for relative movement with respect to a valve seat that is fixed to the housing.

10. Control valve (100) according to claim 8, characterized in that the throttle element (10) is configured as a valve cage which is fixed to the housing, which valve cage has a valve seat (14) and interacts with a valve member (108) that is mounted so as to be movable in the valve housing (102).