JPH01312296A - Pressure reducing porous plate for fluid - Google Patents

Abstract

PURPOSE:To prevent the generation of a cavitation by forming a conical member by a plate member, providing a plurality of holes on a bottom face and a conical curved surface and thereby, efficiently applying a pressure reduction to fluid in a piping. CONSTITUTION:An area enclosed by the diameter D2 of a center part of a metal disk 1 is defined to be the bottom face 11 of a conical part 3 and a plurality of holes are opened. A conical metal member 2 having a plurality of holes opened on a curved surface is placed on the bottom face 11, welded on the circumference of the bottom face 11 to form the conical part 3. A part between the diameters D2, D3 of the metal disk 1 is a flat plate part 4. In the part of the metal conical member 2 of the conical part 3, a passage is changed, the bottom face 11 rectifies and the flat plate part 4 reduces the pressure.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a pressure reducing plate inserted into a fluid flow path.

[Prior Art] Conventionally, in a piping system for transporting a liquid, when reducing the pressure, a pressure reducing valve or an orifice is used.
tion Kano 1fice) have been commonly used.

Among these, pressure reducing valves are commercially available with names such as low-noise valves that serve the purpose of low noise, but they are expensive, and are especially useful in piping systems that transfer ultra-low temperature liquids such as LNG. If special materials must be used,
Since pressure reducing valves are also made of special materials and are more expensive, they are rarely used solely for the purpose of reducing pressure, and are currently not used for anything other than special purposes.

FIG. 5(a) is an explanatory view showing a conventional example of this type of pressure reducing device using an orifice, and FIG. 5(b) is an explanatory view showing occurrence of cavitation due to the orifice 12 of FIG. 5(a).

An orifice 12 is provided in the pipe 11, through which fluid flows in the direction of arrow X. The fluid changes its flow as indicated by arrow Y at the contraction section after passing through the orifice 12. The pressure of the fluid is V at the position P1 in front of the orifice, but is rapidly lowered by the orifice 12, and becomes the saturated vapor pressure of the fluid at the position P2. Thereafter, the lowest pressure Vo is reached at position P, the saturated vapor pressure V is reached again at position P4, and the stable pressure V2 is reached at position P. Then, when the pressure in the contraction section becomes less than the saturated vapor pressure Vl, the fluid changes to gas, and when the pressure recovers to more than the saturated vapor pressure V+ in the downstream pressure recovery section, the gas changes again to liquid. This phenomenon is called cavitation, and when it condenses, a violent impact sound (a sound characteristic of cavitation) is generated. When this phenomenon occurs, the noise level increases and piping vibrations are also caused. In order to avoid a sudden pressure drop due to the orifice 12, a method is often used in which the pressure is gradually lowered using multiple orifices. In this case, the magazine [Piping Technology February 1987 issue JP, 152-P, 1
53, the lowest pressure section created by the final stage orifice is of concern.

[Problems to be Solved by the Invention] The conventional pressure reducing device described above has the disadvantage that the pressure reducing valve is expensive, and when using an orifice, it is multi-staged to prevent cavitation, and the linear spacing between the orifices is also limited by technology. From the above perspective, it is necessary to ensure sufficient
This requires additional space and has the disadvantage of resulting in high costs.

[Means for Solving the Problems] A porous fluid pressure reducing plate of the present invention includes: a cone portion whose outer surface is formed into a cone shape by a plate-like member; and a plurality of holes formed in the curved surface and bottom surface of the cone portion. and a flat plate part which is a plate-like member connected around the bottom surface of the cone part.

[For use] A conical part is formed with a plate-like member, and a plurality of holes are provided in the bottom surface of the conical part and the conical curved surface, and the fluid is inserted into the piping in the direction in which the fluid passes from the conical curved surface side to the bottom surface side. When set, a reduced pressure can be efficiently applied to the fluid by changing the flow path and reducing the pressure with its rectifying action, and cavitation does not occur.

[Embodiments] Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) and 1(b) are a front view and a sectional view taken along the line A-A, respectively, showing an embodiment of the porous fluid pressure reducing plate of the present invention.

The area surrounded by the diameter D2 at the center of the metal disk 1 is defined as the bottom surface 1. of the conical portion 3. A metal conical member 2 having an apex angle θ and having a plurality of holes drilled on a curved surface with a plurality of holes is placed on the bottom surface II and welded around the bottom surface 11 to form a cone portion 3. . In addition, the diameters D2 and D3 of the metal disc 1
The space in between is a flat plate portion 4. A mounting portion 5 is welded to a part of the flat plate portion 4.

Next, a more specific example of this embodiment will be described.

FIG. 2 is a developed view of the metal conical member 2. FIG. As shown in FIG.
Drill holes 1* and 2+, respectively, as shown in the figure. Hole It, 2
The diameter of the metal cone 2 was varied in the range of 1'''/''' to 10'''/''', and the apex angle of the metal conical member 2 was varied in the range of 45 degrees to 120 degrees. Also, the installation was carried out as shown in Figure 3.

The metal conical member 2 part of the conical part 3 changes the flow path and connects to the bottom surface 1. has a rectifying effect, and the flat plate part 4 has a pressure reducing effect, and a portion thereof is also used for attachment. By changing the flow path on the inlet side, the fluid does not directly hit the conventional orifice, and vibrations are alleviated. Further, the bottom surface 1. having a hole 12. rectifies the fluid whose flow path has been changed, thereby preventing sudden pressure changes on the outflow side.

Regarding the apex angle θ, if it is too acute, the flow path change will be excessive and it will be difficult to insert or remove the pipe from between the flanges.

Moreover, if the angle is too obtuse, the flow path change will be insufficient.

If this example is installed in the piping in the direction in which the fluid in the piping passes from hole 2I then through hole 12 as shown in Fig. 3, although it is related to the saturated vapor pressure of the fluid, approximately 10~
It was possible to reduce the pressure by 20 kg/m''. In terms of low noise and vibration, it was comparable in effect to a commercially available multi-stage special pressure reducing device, and particularly good results were obtained in terms of low noise.

Next, an experiment was conducted by inserting a one-stage orifice or a multi-hole fluid pressure reducing plate to which the present invention was applied into the pressure reducing section 22 of a flow path having a minimum flow line as shown in FIG.

Crude gasoline is sucked by the pump 21 through pipe P1 as shown by arrow A, and is discharged as shown by arrow B through pipe P2. A portion of the crude gasoline discharged is transferred to pipe P3.
It passes through the minimum flow line and returns to piping P+. There is a pressure reducing part 2 in the middle of the pipe P to reduce the pressure for recycling.
2 is provided.

The pipes P+, Px, and Ps used in this experiment were 3 inches, the orifice diameter was 23 mm, and the conical part of the fluid porous pressure reducing plate had an apex angle θ of 90° and a bottom surface with an outer diameter of 80 mm. be. The curved surface of the conical part has a plate thickness of 2 mm, and has 70 holes with a diameter of 6 mm. The bottom surface of the conical part has a plate thickness of 5 mm, and has 13 holes with a diameter of 7 mm.

The flow rate of crude gasoline flowing into the minimum flow line is 3
5 cubic meters/hour. The experimental results at each test point are as shown in the table below (the noise level was 1 m from the pressure reducing section 22).
and the vibration was measured at test point T)
.

In this example, the pyramidal part is realized by a cone, but a pentagonal pyramid,
It is clear that pyramids of other shapes than square pyramids may also be used.

Further, the material may be metal, but plastic may be used as long as it is used for fluids that do not cause chemical changes. Moreover, although the attachment part 5 is welded to the flat plate part 4, it is clear that the bottom surface 11, the flat plate part 4, and the attachment part 5 may be punched out of the same member.

[Effects of the Invention] As explained above, the present invention forms a cone portion with a plate-like member and provides a plurality of holes in the bottom surface and the curved surface of the cone.
Since reduced pressure can be efficiently applied to the fluid in the piping and cavitation does not occur, the present invention has the effect of realizing a simple structure that does not take up space, low cost, and noise and vibration prevention of the fluid transport piping.

[Brief explanation of the drawing]

1(a) and 1(b) are front views and AA sectional views showing one embodiment of the fluid porous pressure reducing plate of the present invention, FIG. 2 is a developed view of the metal conical member 2, and FIG. 3 is an explanatory diagram showing the example shown in Figure 1 set in the piping, Figure 4 is an explanatory diagram showing the pipeline used in the experiment, and Figure 5 (a) is a conventional diagram of this type of pressure reducing device. An explanatory diagram showing an example, FIG. 5(b)
5(a) is an explanatory diagram showing the occurrence of cavitation due to the orifice 12 of FIG. 5(a). 1... Metal disk, 11... Bottom surface, L, 2.
... Hole, 2... Metal conical member, 3... Cone part, 4... Flat plate part, 5... Mounting part. Figure 2 Figure m3 (a) (b) Figure 1 Filtering part ε64 Figure PJ5

Claims (1)

[Scope of Claims] A conical part whose outer surface is formed into a conical shape with a plate-like member, a plurality of holes formed in the curved surface and the bottom of the conical part, and a connection around the bottom of the conical part. A porous fluid pressure reducing plate having a flat plate portion which is a flat plate member.