JPS5974499A - Vibration damper for boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a boiler, and in particular to suppressing vibrations occurring within the boiler.

It is known that during operation of a boiler, at certain loads, severe vibrations can occur in the boiler's superheater, reheater, economizer, air heater or heat exchanger. These vibrations were believed to be due to flow vibrations in some or all of the tube rows of the superheater or reheater, since flow vibrations sometimes occur in these tube rows.

Conventionally, in order to control vibrations caused by flow,
One or more baffles were inserted between rows of tubes depending on the harmonic vibration of the standing wave structure, but this method requires placing a large number of baffles in every row of tubes where resonance vibration occurs. The disadvantage is that it is expensive because it requires The present invention uses a single baffle instead of multiple baffles.

The aim of the invention is to overcome or substantially improve the above-mentioned disadvantages.

The present invention includes a chamber in which combustion takes place or combustion gases are conveyed, and a plurality of tubes extending across the chamber generally transversely to the direction of gas flow through the chamber. A boiler installation is disclosed in which the rows extend and the vibration absorbing means extend in a plane perpendicular to the rows of tubes but parallel to the direction of gas flow through the chamber.

Hereinafter, the present invention will be explained in detail by way of examples with reference to the accompanying drawings.

When we investigated the cause of the above vibrations, we found that if the period of occurrence of the thin gas formed behind each pipe is close to the natural period of the gas column extending almost transversely to the gas flow,
It was proposed that strong lateral noise vibrations occur in the lateral gas column.

Due to the influence of this gas column vibration, the generation of thin particles from each cylinder is maintained in phase. Therefore, the imaging of the gas column caused by the eddies generates noise and vibrations in the linear tube heater exchanger, causing the walls of the chamber containing the heat exchanger to vibrate, causing the ambient environment to It was found that noise was emitted.

FIG. 1 schematically shows the wall 10 of the chamber through which the gas 11 heats the row 12 of tubes 13. Since the tubes 3 extend substantially transversely to the direction of the gas flow 11, a vortex 14 is formed in the gas 11 by the tubes 13 and held in phase. When the generation period coincides with the natural period of the gas column extending transversely to the gas flow 11, the walls IO of the chamber are caused to vibrate.

FIG. 2 illustrates four types of natural cycles of the gas column, and these illustrated natural cycles are the cycles that are most likely to occur when flow conditions are considered, especially with respect to the Reynolds number and Struuhal number.

By providing a single vibration absorbing baffle 16 remote from each node 15, energy is absorbed and vibrations of the chamber walls 10 and generation of lateral pickup gas columns are suppressed. A preferred location for the baffle is where the baffle is remote from each node 15 as shown in FIG. Baffle 16 extends in a direction generally parallel to gas flow 11 and is generally located in a plane extending generally perpendicular to the direction of elongation of tube 13.

Although higher natural cycles are possible, the probability of such a higher cycle actually occurring is very small.

Baffles 16 are placed at locations of high gas motion, regardless of the particular lateral period, since the probability of higher periods occurring is very small. Baffle 16 may be formed from a fibrous material to provide good absorption properties during use.

Instead, the absorption baffle 16 is provided by a single perforated plate.
This perforated plate performs the same function as an absorbent baffle 16- made of fibrous material, but has a longer lifespan since there is no filler material that deteriorates or becomes clogged with dust after a period of time. It has the advantage of being

Note that the part h of the present application is a boiler device that has a chamber in which combustion is performed or combustion gas is sent, and a plurality of boiler units are installed across the chamber in a direction substantially transverse to the direction of gas flow through the chamber. "Boiler installation" characterized in that the row of tubes extends and the vibration absorbing means extend in a plane perpendicular to the row of tubes but parallel to the direction of gas flow through the chamber. It is added that the following embodiments are mentioned.

(1) A boiler device in which the vibration absorbing means described above is formed of a perforated sheet material.

(2) A boiler device in which the vibration absorbing means described above is made of a fiber material.

(3) A boiler device in which the vibration absorbing means described above is an absorbing bubble located far from the wall of the chamber.

(4) Paragraph (3) above, wherein the above position is such that the baffle does not pass through the main natural cycle nodes of the gas located between the walls of the chamber. Boiler equipment described in.

(5) The boiler apparatus according to item (4) above, wherein the main periods are the periods of the first four types of gas located between the walls.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows a part of a boiler installation having a row of tubes which absorbs heat from passing combustion gases. FIG. 2 schematically illustrates the imaging of transverse force waves occurring in a passageway containing a row of tubes. Explanation of symbols 10... Wall 11... Gas 12... Row 13
...Tube 14...Wirl 15...Node 16...Baffle

Claims (1)

[Claims] A boiler device having a chamber in which combustion takes place and combustion gases are conveyed, and a row of tubes running across the chamber approximately transversely to the direction of gas flow through the chamber. A boiler installation characterized in that the vibration absorption means extend in a plane perpendicular to the row of tubes but parallel to the direction of gas flow through the chamber.