JPH08186393A - Waveguide filter - Google Patents

Abstract

PURPOSE: To obtain a large and high-performance electromagnetic wave filter with less blast pressure loss. CONSTITUTION: A corrugated plate 2 made of steel where rectangular irregularities are continuously formed is overlapped to the top surface of the irregularities successively in multiples to form a number of square vacant holes 3 in a zigzag manner and two waveguide filter units 1, 1 where the surrounding of a group of the corrugated plates 2 is covered with an outer pipe 4 made of steel plate are arranged opposingly the opening surface of a vacant hole 3 so that the corrugated plates 2, 3 cross each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large waveguide filter (electromagnetic wave filter) for use in a large duct for cooling air blowing in an electromagnetic shield room for large electric power equipment.

[0002]

2. Description of the Related Art A wire net is often used as a conventional large-scale electromagnetic filter for large air flow. In addition, a small-sized copper or copper alloy waveguide filter that has relatively small pressure loss in small air volume and relatively good electromagnetic wave shielding performance is also known. Currently, no high-performance waveguide filter has been developed.

[0003]

The wire mesh conventionally used as an electromagnetic wave filter has a low electromagnetic wave shielding ability and cannot provide a sufficient shielding performance.

Further, the conventional small-sized waveguide filter has a small air volume and an unnecessarily high cutoff frequency, is large in pressure loss and is not suitable for a large air volume, and the material is copper or copper alloy plated with silver or nickel. Many were applied and expensive.

Further, with copper and copper alloys, only a small filter can be manufactured due to the strength of the material, and even if a large filter can be manufactured, it is heavy and very difficult to carry and carry.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the present invention, the corrugated steel plate 2 made of steel plates and having rectangular concavities and convexities continuously formed is successively superposed on top of the concavities and convexities. A large number of square holes 3 are formed in a zigzag shape in total, and two waveguide filter units 1 and 1 in which the periphery of these corrugated plate 2 groups are covered with a steel plate outer tube 4 are formed into two corrugated plates 2. The present invention proposes a waveguide filter in which the opening surfaces of the holes 3 are arranged so as to be orthogonal to each other.

[0007]

In the waveguide filter unit 1 constructed by superposing the corrugated plate 2 made of a steel plate, there is a difference in the shielding performance between the plane parallel to the overlapping plane and the plane perpendicular to the plane, but two waveguide filters are provided. By connecting the units 1 and 1 so that the corrugated plates 2 and 2 are orthogonal to each other, it is possible to obtain the same performance depending on directions.

[0008] Particularly, when the whole is galvanized, the difference in the shielding performance depending on the direction is small, and the shielding performance is further improved when the two are connected in an orthogonal manner.

Since the parts can be carried in to the construction site and assembled, they can be easily carried and carried in.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, a waveguide filter unit 1 has a large number of corrugated steel plates 2 formed by continuously forming rectangular concavities and convexities on the top surface of the concavities and convexities. The rectangular holes 3 are formed in a zigzag shape, and the corrugated plate 2 group is covered with a steel plate outer tube 4. Desirably, hot dip galvanization is performed on the entire corrugated plate 2 and the corrugated plate plates 2 are stacked. The concave and convex top surfaces and the top surface and the overlapping surface of the outer tube 4 are fastened together by a screw 5 such as a self-tapping screw to be closely integrated.

When this waveguide filter unit 1 is used as a waveguide filter for a blower opening, as shown in FIG. 3, the waveguide filter units 1 and 1 are formed so that their corrugated plates 2 are orthogonal to each other. The opening surfaces of the holes 3 are arranged to face each other so that, for example, as shown in FIG. 4, a fastening flange 6 is provided on the outer periphery of each opening surface to surround the opening of the wall such as the shield partition 7. They are fastened together by bolts 8 and attached.

FIG. 4 shows an outline of a performance test of the waveguide filter of the present invention, in which a transmission room 9 and a reception room 10 which are shield rooms are connected via a shield partition 7 having an opening in the middle. The transmitter antenna 11 is installed in the transmitter room 9
Is installed and an electromagnetic wave is emitted from the transmitter 12 via the coaxial cable 13, and this electromagnetic wave is received by the receiving antenna 14 provided in the receiving chamber 10 and sent to the receiver 16 via the coaxial cable 15 to change the electric field strength. The electric field strength when the opening was opened and the electric field strength when the waveguide filter of the present invention was attached were measured, and the target shielding performance was measured by the difference.

The results are shown in FIG. It is understood from the graph of FIG. 5 that the waveguide filter of the present invention has an electromagnetic wave attenuation performance of 60 dB or more over 10 kHz to 1000 MHz.

[0014]

As described above, according to the present invention, the corrugated steel plates formed by continuously forming the rectangular unevenness are sequentially superposed on the top surface of the unevenness to form a large number of square holes in a staggered manner. Since it is formed and the waveguide filter unit in which the periphery of these corrugated plate groups is covered with a steel plate outer tube is used,

When used in a large duct for cooling air blowing in an electromagnetically shielded room for a large-scale electric power facility, a high-performance electromagnetic filter with a large blowing pressure loss can be obtained.

Further, since the two waveguide filter units are connected so that the corrugated plates are orthogonal to each other, it is possible to obtain the same performance depending on the direction, and particularly the whole is galvanized. The thing can reduce the difference in the shielding performance depending on the direction.

Further, the waveguide filter unit can be carried into the construction site and assembled at the construction site, and since the parts are also made of steel plate and the manufacturing cost can be reduced, it is easy to carry and carry-in and construct an inexpensive filter. You can

[Brief description of drawings]

FIG. 1 is a front view of a waveguide filter unit according to the present invention.

FIG. 2 is a partially enlarged front view of the waveguide unit according to the present invention.

FIG. 3 is a perspective view showing a connection arrangement state of the waveguide unit according to the present invention.

FIG. 4 is a cross-sectional plan view showing a state where a performance test of the waveguide filter of the present invention is performed.

FIG. 5 is a diagram showing the results of a performance test of the waveguide filter of the present invention.

[Explanation of symbols]

 1 Waveguide Filter Unit 2 Corrugated Plate 3 Square Hole 4 Outer Tube 5 Screw 6 Fastening Flange 7 Shield Partition 8 Volt 9 Transmitting Room 10 Receiving Room 11 Transmitting Antenna 12 Transmitter 13 Coaxial Cable 14 Receiving Antenna 15 Coaxial Cable 16 Receiver

Claims (2)

[Claims] 1. A corrugated plate made of steel sheet, which is formed by continuously forming rectangular corrugations, is sequentially superposed on the top surface of the corrugations to form a large number of square holes in a zigzag pattern, and the corrugated plate group is surrounded. The two waveguide filter units, each of which is covered with a steel pipe outer tube, are arranged such that the opening surfaces of the holes are arranged so that the corrugated plates are orthogonal to each other. Wave tube filter. 2. A corrugated plate made of steel sheet, which is formed by continuously forming rectangular corrugations, is sequentially superposed on the top surface of the corrugations to form a large number of square holes in a zigzag shape, and the corrugated plate group is surrounded. And two waveguide filter units, each of which is covered with a steel pipe outer tube and which is entirely galvanized, are arranged such that the opening surfaces of the holes are opposed to each other so that the corrugated plates are orthogonal to each other. A waveguide filter characterized by being formed.