RU200098U1 - STEAM EMISSION SILENCER - Google Patents

Abstract

The utility model refers to technological devices, the mechanism of action of which is based on the stepwise throttling of the vapor-air medium in order to reduce its velocity and change the sound pressure level generated when steam is emitted into the atmosphere at power facilities. The objective of the utility model is to develop a silencer for the noise of steam emissions, in which the disadvantages of similar devices have been eliminated. The technical result is the development of a silencer for noise emissions of steam operating in the frequency range 63.5-8000 Hz, having small dimensions when operating in broadband ranges due to the installation of throttling blocks, and also having thermal insulation to prevent moisture condensation and its subsequent freezing on the walls of the apparatus. The technical result is achieved by the fact that a silencer for noise emission of steam, having a cylindrical shape, consisting of resonators installed in the rupture of the exhaust gas pipeline, while sound waves propagating along the acoustic transparent p perforated pipeline in the exhaust gas environment, excite natural oscillations, according to the present utility model, additionally introduced throttle blocks 6 and 8, consisting of perforated pipes 2, fixed by welding to the lower and upper bearing elements, designed for throttling steam, as well as resonator blocks 5 and 7, which are spaces bounded by walls, in which steam expands and low-frequency sounds are damped, and block 9 for final expansion and emission of steam into the atmosphere, while the blocks are removable for acoustic tests and adjusting the silencer, also for amplification the effect of reducing the noise level, the middle stages of the silencer are lined with sound-absorbing material 3, fixed with a metal mesh, and a baffle plate 4 is provided to direct the flow of steam along the walls of the housing of the silencer 1 of the output stage, around which the steam is emitted into the atmosphere from under the installed on the well roof shutter 10.

Description

Technology area

The utility model refers to technological devices, the mechanism of action of which is based on the stepwise throttling of the vapor-air medium in order to reduce its speed and change the level of sound pressure generated when steam is released into the atmosphere at power facilities.

State of the art

Energy industry enterprises are constant sources of industrial noise that affects nature and humans. The most noticeable component of the background noise of such objects is vapor emissions into the atmosphere, during which the sound level is temporarily exceeded by 30-40 dBA within a radius of several kilometers. Steam emissions occurring during start-up and shutdown operations on boiler units, activation of emergency automation and, in many cases, are mandatory in the technological process.

Silencers of steam emissions are an effective solution to the problem of protecting people from the negative effects of high noise levels. Their purpose is to reduce the sound pressure level generated by steam emissions on the territories of energy enterprises and in the surrounding areas to the values established in SN 2.2.4 / 2.1.8.562-96 "Noise at workplaces, in residential, public buildings and on the territory residential development ", SanPiN 2.2.4.3359-16" Sanitary and epidemiological requirements for physical factors in the workplace "and other regulatory documents.

Tubular mufflers currently used at thermal power plants have limited capabilities to reduce the noise level in the low-frequency region of the audio frequency range. In silencers of this type (patent for invention No. RU 2525993 C1, 03/21/2013 IPC F01D 25/30; utility model patent No. RU 104970 U1, 30.12.2010, IPC F01D 25/30), sound energy is lost in the layer of sound-absorbing material. A known disadvantage arising during the operation of such mufflers is the high degree of clogging of their structural elements.

There are also known prototypes and working models of jet-type silencers with direct-flow gas mixture flow (patent for invention No. RU 2389882 C1, 15.01.2009, F01N 1/00; patent for invention No. RU 2306430 C2, 15.12.2005, IPC F01N 1/00 ; patent DE 1196877 AB).

Reactive mufflers hinder the transmission of acoustic vibrations due to the formation of a wave plug, which randomly reflects sound waves. They, as a rule, represent in one form or another a resonant cavity or connected cavities. In mufflers of this design, the damping effect is achieved mainly by reflecting the sound energy back to the source. The design disadvantage of such mufflers is the formation of secondary noise generated when the gaseous stream flows through the muffler grilles.

As an alternative to existing developments, it is proposed to use a combined type sound attenuator. The mechanism of action of the developed muffler is based on typical schemes for noise suppression of gas discharge systems, the principle of which is based on step throttling. The closest in terms of technical component is a resonant reflective muffler (RF patent for invention No. 2468217, 01/21/2011, IPC F01N 1/02, F16L 55/033, F24F 13/24). The principle of operation of this silencer is to use Helmholtz resonators in the mode reflection of sound, by establishing the relationship between the impedance of the resonator and the impedance of the medium in the pipeline. The disadvantage of this type of device is that it is capable of absorbing sound only in broadband frequencies; in addition, for effective noise reduction in the mode of broadband sound absorption, a large number of small-sized Helmholtz resonators are required. In cases of real production, to install such a number of Helmholtz resonators, it will be necessary to increase the overall dimensions of the silencer, which will lead to difficulties in installing it on the roof of the boiler room. The second disadvantage of this device is the lack of thermal insulation, which, under conditions of irregular operation of the exhaust steam line, will lead to condensation of moisture and its subsequent freezing on the walls of the apparatus.

The main task solved in the proposed device is to create optimal conditions for suppressing sound radiation into the environment in the exhaust pipelines of steam of energy objects. Reducing the sound level in the muffler consists of five levels, including choke, resonator and expansion stages. To enhance the effect of reducing the noise level, the middle stages of the silencer are lined with sound-absorbing material, which also acts as a thermal insulation of the body. This design of the silencer allows to reduce the flow rates of steam generated by pressure drops during the operation of the safety valve. This is easily explained by the fact that due to the significant influence of the flow velocity on the sound level of the free jet, any change in the first value will entail a change in the sound power value. The main difference between the developed silencer of noise emission of steam from the closest analogue is consistent. the location and geometry of the jamming stages, the directivity of which is designed for the frequency range 63.5-8000 Hz, in accordance with the standardized parameters and the maximum permissible noise levels at workplaces (CH 2.2.4 / 2.1.8.562-96), while the silencer (patent RF for invention No. 2468217), the sound absorption is calculated only in the broadband range. The proposed device is capable of operating in a wide range of temperatures of the working environment and does not create aerodynamic drag that affects the performance of the steam exhaust pipe.

Disclosure of a utility model

The task of the utility model is to develop a silencer for noise emissions of steam, which eliminates the disadvantages of similar devices.

The technical result is the development of a steam emission noise muffler operating at a frequency range of 63.5-8000 Hz, having small dimensions when operating in broadband ranges due to the installation of throttling blocks, and also having thermal insulation to prevent moisture condensation and its subsequent freezing on the walls of the apparatus.

The technical result is achieved by the fact that a vapor emission noise muffler, having a cylindrical shape, consisting of resonators installed in the rupture of the exhaust gas outlet, while the sound waves propagating through the acoustic transparent perforated pipeline in the exhaust gas environment excite natural vibrations, according to this useful models, additionally introduced throttling blocks 6 and 8, consisting of perforated pipes 2, fixed by welding to the lower and upper load-bearing elements, intended for throttling steam, as well as resonator blocks 5 and 7, which are spaces bounded by walls in which expansion of steam and damping of low-frequency sounds, and block 9 for the final expansion and release of steam into the atmosphere, while the blocks are removable for performing acoustic tests and adjusting the silencer, also to enhance the effect of reducing the noise level, the middle stages of the silencer are lined with sound a baffle plate 4 is provided to direct the flow of steam along the walls of the housing of the muffler 1 of the output stage, around which the steam is emitted into the atmosphere from under the roof 10 installed on the muffler.

Sound waves arising from the expansion of the steam jet in the first resonator block 5 of the silencer resonate in its volume and cause natural acoustic oscillations. Then, in the first throttle block 6, the flow is divided into four parts with a change in the flow rate and its acoustic power. The resonant frequency is determined by the number of holes and the geometric characteristics of the throttling tubes 2. After that, the throttled steam enters the second resonator unit 7, where the noise is reflected and partially absorbed. In the volume of the second throttle unit 8, a division into a large number of streams occurs with a change in their speed and a decrease in the noise level. At the final stage, the steam is directed through the throttling pipes 2 to the expansion unit 9, where the final formation of the sound power of the flow and its release into the atmosphere takes place.

Implementation of the utility model

A diagram of a steam emission silencer is shown in Fig. 1.

The numbers in FIG. 1 are marked:

1 - silencer housing;

2 - throttling pipes;

3 - sound-absorbing material;

4 - baffle plate;

5 - the first resonator unit;

6 - the first throttle unit;

7 - the second resonator unit;

8 - the second throttle unit;

9 - expansion unit;

10 - roof.

The silencer for noise emissions of steam is installed on the exhaust steam line located on the roof of the power facility. Exhaust pipelines serve as lines for the discharge of steam from the safety valves of the boiler unit to the atmosphere.

The muffler of noise emission of steam works as follows. Under the conditions of use, the muffler is installed on the exhaust steam line of the safety and relief valve of the steam boiler. The dimensions of the device are made depending on the results of mathematical modeling with reference to a real object - a noise source. Steam, entering from the exhaust pipe, expands in the resonator block 5, and then enters the throttle pipes 2. The upper ends of the pipes of the first throttle block 6 are muffled, due to which the steam is throttled, passing through many holes in the pipes, while the sound characteristic will change, i.e. .to. The total sound power level of the steam emission is directly dependent on the outlet jet velocity and the pipeline cross-sectional area. Then, through four holes made in the upper supporting element of the first throttle unit 6, the steam enters the second resonator unit 7, where low frequency sounds are damped. After the resonator, steam enters the base of the second throttle unit 8, in which the lower ends of the throttle tubes are muffled, and the upper ends of the tubes have an outlet to the expansion unit 9. Under the action of pressure, steam through the holes enters the tubes, then from which it is directed to the outlet stage, where final expansion and release of steam into the atmosphere.

Such a silencer device will allow reducing the steam flow rates, which will entail a decrease in the sound power.

Claims (1)

Silencer of steam emission noise, having a cylindrical shape, consisting of resonators installed in the rupture of the exhaust gas outlet, while sound waves propagating through the acoustic transparent perforated pipeline in the exhaust gas environment excite natural oscillations, characterized in that additionally choke units are introduced, consisting of perforated pipes, welded to the lower and upper supporting elements, intended for throttling steam, as well as resonator blocks, which are spaces bounded by walls in which steam expands and low frequency sounds are damped, and a block for final expansion and steam emission into the atmosphere, while the blocks are made removable for performing acoustic tests and adjusting the silencer, the upper ends of the pipes of the first choke block are plugged, the lower ends of the pipes of the second choke block are plugged, and the upper ends roughly have an outlet to the expansion unit, i.e. Also, to enhance the effect of reducing the noise level, the middle stages of the silencer are lined with sound-absorbing material, fixed with a metal mesh, and a baffle plate is provided to direct the flow of steam along the walls of the housing of the output stage silencer, around which the steam is emitted into the atmosphere from under the roof installed on the silencer.

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