JPH08200014A - Steam converter - Google Patents

Abstract

PURPOSE: To prevent the generation of noises and vibrations by scattering and decompressing further on two steps steam decompressed in a first decompression part by a second decompressive rectifying part while rectifying the steam flow by a perforated plate. CONSTITUTION: Dry steam supplied from a steam pipe 21 is at first decompressed by a throttle valve, thereafter introduced into a second decompression rectifying part B and further decompressed through a base tube part 31 and conical drum part 32. Next, the steam is decompressed and rectified through small diameter apertures in first - third perforated plates 24A-24C. Thus, relatively uniform mild flows are realized and the generation of swirl flow in the decompression is restrained. Thus, clean water infused from a feed nozzle can be flushed to be effectively mixed. Also, since the infused clean water can be preheated to provide saturated water by steam sent in an expanded path through a feed pipe consisting of a plurality of preheating thin pipes, the clean water can be easily flushed from the feed nozzle to be gasified for improving the mixing efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam converter for reducing the pressure of steam, such as a turbine bypass system, in a power plant using a boiler turbine.

[0002]

2. Description of the Related Art A conventional steam conversion valve for decompressing and reforming steam is, for example, as shown in FIG.
1 and the cooling water supply unit 2 were integrally formed, and the mixing unit 3 was provided on the downstream side of the throttle unit 1. That is, the throttle unit 1 is configured by arranging an adjusting cylinder 5 in which a plurality of valve holes 5 a are formed in a casing 4 and internally inserting a valve body 7 slid by an operating rod 6 in the adjusting cylinder 5. There is. Further, in the cooling water supply unit 2, fresh water is supplied from the cooling water supply pipe 8 connected to the casing 4 to the annular groove 9a of the nozzle member 9 provided on the outer peripheral portion of the adjustment cylinder 5, and the nozzle hole 9b serves as a valve hole. It is configured to inject fresh water into the discharge side of 5a. Further, the mixing section 3 is provided with a reducer section 10 that spreads toward the discharge side outside the adjustment cylinder 5, and a conical perforated plate 11 is provided at the discharge port to stir and mix the saturated steam into which fresh water has been injected. It is configured to rectify.

[0003]

However, the vapor conversion valve is a compact one or a peripheral portion of the valve hole 5a, in which the sonic flow is throttled by the throttle portion 1 and fresh water is further injected to mix and stir. As a result, a jet flow is generated and vortex vibration is generated, and the throttle is concentrated on the adjusting cylinder 5, so that extremely intense noise is generated. This is considered to be a problem in that the flow of the fluid is not improved with emphasis on throttling (decompression) and mixing.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a vapor conversion device capable of preventing the generation of noise and vibration.

[0005]

In order to solve the above-mentioned problems, a steam conversion device of the present invention is provided in an expansion passage on the outlet side of a first pressure reducing portion formed of a throttle valve interposed in the steam passage. A second depressurization rectification unit having a perforated plate is provided, and a water supply nozzle is disposed at the outlet of the second depressurization rectification unit.

In addition to the above construction, the water supply pipe of the water supply nozzle is arranged along the axial center of the expansion passage, and
It is composed of a plurality of preheating thin tubes.

[0007]

In the above structure, the steam decompressed by the first decompression section is further dispersed by the second decompression rectification section in two stages to be decompressed, and the steam flow is rectified by the perforated plate, so that a supersonic flow is generated. It is possible to realize a relatively uniform and mild steam flow, which prevents the generation of vortex flow in the decompression unit and suppresses the generation of vibrations and noise, and from the water supply nozzle at the outlet of the second decompression rectification unit. The injected fresh water can be flushed and mixed effectively. Further, since the fresh water is injected after the depressurization, the pressurizing device of the fresh water required when injecting before the depressurization becomes unnecessary.

Further, the fresh water to be injected can be preheated to saturated water by the steam sent through the expansion passage through the water supply pipe consisting of a plurality of preheating thin tubes, so that it can be easily flushed from the water supply nozzle. Can be vaporized,
The mixing efficiency can be increased. Further, since the preheating thin tube is built in the expansion passage, the entire structure can be made compact.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the vapor conversion device according to the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the vapor conversion device is
A first pressure reducing portion A including a known throttle valve 22 connected to a steam pipe 21 to which dry steam is supplied, an expansion passage 23 connected to an outlet of the throttle valve 22, and a plurality of first to third porous holes. A second depressurizing rectifying section B having plates 24A to 24C, and a water supply nozzle 25 for injecting fresh water into the steam at the outlet of the expansion passage 23.
And a water injection section C provided with a water supply device 26 to the water supply nozzle 25.

The second depressurizing rectifying section B is a base cylinder portion 31 connected to the throttle valve 22 via a flange, and a cone whose diameter is expanded from the outlet of the base cylinder portion 31 toward the downstream side to form an expansion passage 23. The conical body 32 includes a body 32 and a discharge cylinder 33 connected to an outlet of the conical body 32. The conical body 32 is provided with three spherical perforated plates 24A to 24C at a predetermined interval in the flow path direction. It is attached in a substantially concentric manner so that the distance is constant in the road direction.

The water supply device 26 of the water injection part C is supplied from a water injection pipe 34 penetrating the base cylinder part 31 to a water distributor 35 provided at the outlet of the base cylinder part 31, and further supplied from the water distributor 35. It is connected to the water supply nozzle 25 via a water supply pipe 36 composed of the preheating thin pipe 36a.

The water injection pipe 34 has a through hole 31a formed in the base cylinder portion 31 into which the water injection pipe 34 is loosely fitted, and a holding cylinder 31b projecting from the base cylinder portion 31 corresponding to the through hole 31a. It is introduced into the base tube portion 31 via the support tube 31 and is held by an end plate 31c provided at the tip of the holding tube 31b. Thereby, the thermal stress generated in the base cylinder part 31 due to the temperature difference between the steam and the fresh water can be avoided. The water divider 35 distributes the fresh water supplied from the bypassed water injection pipe 34 to the plurality of preheating thin tubes 36a, and is supported by the four support plates 37 at the axial center position of the base tube portion 31. There is. Further, the preheating thin tube 36a connected to the water divider 35 is provided with each porous plate 24A.
24C to 24C are formed in the axial center portion of the expansion passage 23 through the through holes 24a to 24c, and the pipes are provided with a predetermined gap therebetween.

As shown in FIG. 2, the water supply nozzle 25 has a cylindrical body plate 41a and a bottom plate 41 on the back surface of the third porous plate 24C.
The casing 41 composed of b is attached, and the preheating thin tube 3 is provided through the through hole 24c formed in the third porous plate 24C.
6a is connected. A core 42 that forms a ring-shaped water supply space 41c is attached to the outer peripheral portion of the bottom plate 41b in the casing 41.
1a is provided with vertical water injection slits 43 facing the water supply space 41c at regular intervals in the circumferential direction, and the bottom plate 4
Conical water injection holes 44 are formed at 1b at regular intervals in the circumferential direction.

In the above structure, the dry steam supplied from the steam pipe 21 is first decompressed by the throttle valve 22 of the first decompression unit A, then introduced into the second decompression rectification unit B, and the base cylinder unit 3
The pressure is further reduced in the expansion passage 23 spreading from 1 to the conical barrel portion 32, and the vapor is decompressed and rectified by passing through the small diameter holes of the first to third porous plates 24A to 24B. The steam heats the fresh water injected through the preheating thin tube 36a to raise the temperature to saturated water or saturated water. Then, when passing through the third perforated plate 24C, fresh water is evenly ejected from the water injection slit 43 of the water supply nozzle 25 in the circumferential direction to be flushed and vaporized, and at the same time, the fresh water is ejected from the water injection hole 44 in the axial direction. It vaporizes and forms saturated vapor.

According to the above structure, the first decompression section A and the second decompression rectification section B disperse in two stages to reduce the pressure, thereby preventing the sonic flow in which steam flows at an extremely high speed to generate vibration and noise. Along with being able, the first to third porous plates 24A to 24
By passing C, the steam flow can be further depressurized and rectified, so that a relatively uniform and mild flow can be realized, which prevents the generation of a vortex at the time of depressurization and causes vibration and noise. Effectively suppressed. Then, the fresh water injected from the water supply nozzle 25 can be flushed at the outlet of the second depressurization rectification unit B to be effectively mixed, and saturated steam can be formed. Moreover, since the fresh water is injected into the steam after the depressurization, the pressurizing device for the fresh water, which is necessary before or during the depressurization, becomes unnecessary.

The fresh water to be injected is supplied to a plurality of thin tubes 36a.
Since it is possible to preheat the expansion passage 23 by the steam sent through the water supply pipe 36 to be saturated water,
A preheater for fresh water is not required, and it can be easily flashed from the water supply nozzle 25 to be vaporized, and the mixing efficiency can be improved. Further, the preheating thin tube 36a is connected to the expansion passage 2
Since it is arranged inside 3, the whole can be made compact.

[0018]

As described above, according to the steam converter of the present invention, the steam depressurized by the first depressurizing unit is further divided into the second steam.
Since the vapor flow is rectified by the perforated plate while decompressing in two stages by the decompression rectification unit, a relatively uniform and mild vapor flow can be realized without the generation of supersonic flow. It is possible to prevent the generation of a vortex flow in the section, suppress the generation of vibration and noise, and flush the fresh water injected from the water supply nozzle at the outlet of the second depressurization rectification section to effectively mix it. Further, since the fresh water is injected after the depressurization, the pressurizing device of the fresh water required when injecting before the depressurization becomes unnecessary.

Further, the fresh water to be injected can be preheated to saturated water by the steam sent through the expansion passage through the water supply pipe consisting of a plurality of preheating thin tubes, so that it can be easily flushed from the water supply nozzle. Can be vaporized,
The mixing efficiency can be increased. Further, since the preheating thin tube is built in the expansion passage, the entire structure can be made compact.

[Brief description of drawings]

FIG. 1 is a central longitudinal sectional view showing an embodiment of a vapor conversion device according to the present invention.

FIG. 2 is a vertical cross-sectional view showing a water supply nozzle of the vapor conversion device.

FIG. 3 is a central longitudinal sectional view showing a conventional vapor conversion valve.

[Explanation of symbols]

 A 1st decompression part B 2nd decompression rectification part C Water injection part 21 Steam pipe 22 Throttle valve 23 Expansion passage 24A-24B 1st-3rd perforated plate 25 Water supply nozzle 26 Water supply device 31b Holding cylinder 32 Conical body part 34 Water injection pipe 35 Water Divider 36 Water Supply Pipe 36a Preheating Thin Tube 41 Casing 43 Water Injection Slit 44 Water Injection Hole

Claims (2)

[Claims] 1. A first valve comprising a throttle valve interposed in a steam passage.
The second side in which a perforated plate is arranged in the expansion passage on the outlet side of the pressure reducing section
A vapor conversion device comprising a decompression rectification unit, and a water supply nozzle arranged at the outlet of the second decompression rectification unit. 2. The steam converter according to claim 1, wherein the water supply pipe to the water supply nozzle is arranged along the axial center of the expansion passage and is constituted by a plurality of preheating thin tubes.