JP3198737B2 - Small amplitude damper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention suppresses minute vibrations generated in cooling water circulating pumps and piping systems installed in chemical plants, thermal power plants and nuclear power plants, etc., and also reduces vibrations in piping systems such as marine engines. The present invention relates to a damper for small amplitude, which can be used for suppression, an engine body, and the like.

[0002]

2. Description of the Related Art In general, cooling water circulation pumps and piping systems installed in chemical plants, thermal power plants and nuclear power plants are supported by a fixed system such as a building by a plurality of supporting devices such as mounts and straddles, and mechanical snacks. Vibration generated by a vibration damping device such as a bar is effectively attenuated to ensure safety against vibration. As is well known, this mechanical snubber receives and attenuates the dynamic displacement that occurs during an earthquake or when the pump is driven, etc., to attenuate the damage to the objects to be supported such as the cooling water circulation pump and the piping system. In addition to preventing the displacement, static displacement such as thermal expansion generated by increasing the temperature of the coolant due to the rise of the cooling water is allowed.

[0003]

This mechanical snubber works effectively against large vibrations such as earthquakes and pump vibrations. However, this mechanical snubber has mechanical backlash and friction at the connection portion and inside. , 0.1-0.2 mm was impossible to stop. In particular, in a cooling water circulating pump of a nuclear power plant requiring extremely high safety, the continuation of such minute vibrations may have a great effect.

The present invention has been devised in order to effectively solve the above problems, and an object of the present invention is to effectively suppress minute vibrations generated in a cooling water circulating pump and a piping system of a nuclear power plant. An object of the present invention is to provide a small amplitude damper that can be suppressed.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a small-amplitude damper for suppressing minute vibration between a fixed flange and a movable flange. A heavy bellows cylinder is provided, an outer working fluid chamber is formed between the inner and outer bellows cylinders, and a closing plate is provided in the inner bellows cylinder, and an air chamber communicating the inside with the outside through an intake / exhaust port is provided. An orifice means for forming a partition in the inner working fluid chamber, filling the inner and outer working fluid chambers with working fluid, and circulating the working fluid in the inner and outer working fluid chambers; As the fluid, an electrorheological fluid whose viscosity changes continuously according to the applied electric field strength is used.

[0006]

According to the present invention, when the compressive and tensile loads, that is, when the movable flange moves close to and away from the fixed flange due to vibration, the air in the air chamber in the inner bellows cylinder expands and contracts, so that the inner and outer bellows cylinders are expanded. The pressure in the outer working fluid chamber and the pressure in the inner working fluid chamber in the inner bellows cylinder alternately change. When the viscous working fluid in the two working fluid chambers passes through the orifice means and alternately reciprocates in the two working fluid chambers due to the pressure change, the orifice means becomes a flow resistance of the working fluid and becomes a movable flange. , That is, vibration is attenuated and suppressed. In addition, by using an electrorheological fluid instead of a viscous normal fluid as the working fluid, the flow resistance of the working fluid changes according to the applied voltage, so that the vibration damping performance can be continuously varied. You can also.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 to 3 show an embodiment of a small-amplitude damper A according to the present invention. As shown in the figure, this small-amplitude damper A extends and contracts between a fixed flange 1 fixed to a wall B of a building and a movable flange 2 connected to a support object C such as a cooling water circulation pump or a piping system. A flexible outer bellows cylinder 3 is provided, and the movable flange 2 can move close to and away from the fixed flange 1. A disk-shaped orifice means 4 for partitioning the inside of the outer bellows cylinder 3 and an inner bellows cylinder 5 for connecting the orifice means 4 and the fixed flange 1 are provided in the outer bellows cylinder 3. Due to the orifice means 4 and the inner bellows cylinder 5, the inside thereof is formed in the outer fluid working chamber 9.
And a movable flange side fluid working chamber 10. A closing body 6 is provided at a substantially central portion in the inner bellows cylindrical body 5, and the orifice means 4 is defined as an internal working fluid chamber 7, and the fixed flange 1 is defined as an air chamber 8. The outer fluid working chamber 9, the movable flange side fluid working chamber 10, and the inner working fluid chamber 7 are filled with a highly viscous working fluid S.

As shown in FIG. 2, a plurality of orifices 11a, 11b, 11b... Are formed in the center of the disk-shaped orifice means 4 and at the peripheral edge thereof. The working fluid S is mutually circulated between the movable flange side fluid working chamber 10 and between the movable flange side fluid working chamber 10 and the internal working fluid chamber 7.

The fixed flange 1 is provided with a suction / exhaust hole 12 communicating with the air chamber, and the air chamber 8 is open to the atmosphere. In addition, the suction and exhaust holes 12 are fixed to the fixed flange 1.
Need not be formed in a tube-like pipe (not shown)
The outer fluid working chamber 9 and the outer bellows cylinder 3 may be formed to penetrate the air chamber 8 directly from the air chamber 8 or the like, or the air chamber 8 may be sealed in some cases. The outer bellows cylindrical body 3 and the inner bellows cylindrical body 5 are well-known metal bellows, which can expand and contract in the length direction, but have extremely rigid properties in expansion and contraction in the radial direction. .

Next, the operation of this embodiment will be described.

First, as shown in FIG. 4, when a fluid flows or a vibration is generated by driving a motor (not shown) or the like, a tensile stress, that is, the movable flange 2 is drawn in a direction opposite to the fixed flange 1. When the outer bellows cylinder 3 is extended, the inside of the outer fluid working chamber 9 and the movable flange side fluid working chamber 10 communicating therewith are brought into a negative pressure state.
The inside of the inside working fluid chamber 7 and the inside of the air chamber 8 which are in communication with each other are also in a negative pressure state. Then, external air flows into the air chamber 8 from the suction / exhaust hole 12, and as the air chamber 8 expands and increases in volume, the working fluid S in the inner working fluid chamber 7 moves to the center of the orifice means 4. From the orifice 11a through the movable flange side fluid working chamber 10 side
b, 11b... flows into the outer fluid working chamber 9. The working fluid S is supplied to the orifice 11a.
, 11b, 11b,..., Which acts as a flow resistance to suppress the separation movement of the movable flange 2 in the opposite direction to the fixed flange 1 side, thereby attenuating the tensile stress.

On the other hand, when the compressive stress, that is, when the movable flange 2 is pulled toward the fixed flange 1, FIG.
As shown in (1), the pressure inside the outer fluid working chamber 9, the movable flange-side fluid working chamber 10, and the movable flange-side fluid working chamber 10 rises, and the air in the air chamber 8 is exhausted and contracted. The fluid S flows in the opposite direction to the above,
This becomes flow resistance, and the approach movement of the movable flange 2 to the fixed flange 1 side is suppressed, and the compressive stress is attenuated.

Since these operations are performed alternately in a short time, the minute vibration of the movable flange 2, that is, the vibrating portion C as shown in FIG. 3 is effectively suppressed and suppressed. In this embodiment, the operation in the case of the vibration generated on the movable flange 2 side has been described. However, the same operation can be performed when the vibration is generated on the fixed flange 1 side provided on the building B side due to an earthquake or the like. Of course, the vibration is damped and suppressed. It is also possible to obtain a desired damping performance by arbitrarily setting the viscosity of the working fluid or the size of the orifice.

When the pipe is thermally deformed due to thermal stress or the like, its movement is extremely slow, so that there is almost no flow resistance at the orifice portion, so that the resistance to deformation is only the spring force of the bellows. Since this spring force is sufficiently small as compared with that due to the rigidity of the pipe, it does not adversely affect the pipe. Further, by appropriately selecting the number of peaks, the diameter, and the plate thickness of the bellows, it is possible to realize a damper that attenuates a minute vibration displacement while allowing a large slow deformation such as a thermal deformation.

FIG. 6 shows a second embodiment of the present invention.

As shown, in the present embodiment, the working fluid S
The electrodes 13 and 13 are provided in the orifice means 4 which comes into contact with the fluid, and an electrorheological fluid (ER fluid) is used as the working fluid S. As is well known, this electrorheological fluid has the property that its apparent viscosity changes continuously depending on the applied electric field strength. Usually, starch, cellulose, alumina, and ion exchange resin are contained in an insulating dispersion medium. Etc. are dispersed.

Therefore, in this embodiment, the apparent viscosity of the working fluid S changes continuously by controlling the voltage applied to the electrodes 13 and 13 from the controller 14, so that an arbitrary damping coefficient can be obtained. A variable damper that can be constructed can be configured.

[0019]

In summary, according to the present invention, minute vibrations generated in the cooling water circulation pump of a nuclear power plant and its piping system can be effectively suppressed, and the damping performance can be arbitrarily varied as required. It has excellent effects such as the ability to

It is clear from the operational characteristics of the present invention that the present invention can be used not only for piping systems of plants, but also for vibration control of marine engines and the like, as well as vibration damping mounts for engines.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrows AA in FIG.

FIG. 3 is an explanatory view showing one embodiment of a mounting state of the device of the present invention.

FIG. 4 is an explanatory diagram showing an operation when a tensile stress is applied.

FIG. 5 is an explanatory diagram showing an operation when a compressive stress is applied.

FIG. 6 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 fixed flange 2 movable flange 3 inner bellows cylinder 4 orifice means 5 outer bellows cylinder 6 closing plate 7 inner working fluid chamber 8 air chamber 9 outer working fluid chamber S working fluid

Continuation of the front page (56) References JP-A-4-321835 (JP, A) JP-A-61-270532 (JP, A) JP-A-60-73144 (JP, A) JP-A-55-112440 (JP) , A) Japanese Utility Model Hei 5-94546 (JP, U) Japanese Utility Model Hei 1-67343 (JP, U) Japanese Utility Model Showa 53-63251 (JP, U) Japanese Utility Model Showa 64-48635 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) F16F 9/10 F16F 9/53

Claims (2)

(57) [Claims] 1. A small-amplitude damper for suppressing minute vibration between a fixed flange and a movable flange, wherein a double inner and outer bellows cylinder is provided between the fixed flange and the movable flange. An outer working fluid chamber is formed in the inner bellows cylinder, a closing plate is provided in the inner bellows cylinder, and the inside is partitioned into an air chamber and an inner working fluid chamber communicating with the outside through an intake / exhaust port, and the inside and outside operation is performed. A small-amplitude damper, characterized in that an orifice means for filling a working fluid in each of the fluid chambers and flowing the working fluid in the inner and outer working fluid chambers is provided. 2. The small-amplitude damper according to claim 1, wherein an electrorheological fluid whose viscosity continuously changes according to an applied electric field intensity is used as the working fluid.