JP2001025686A - Spray nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spray nozzle which can reduce the pressure difference of the nozzle and improve controllability by widening the control range of a flow rate control valve installed upstream from the nozzle. SOLUTION: In a spray nozzle 8 comprising an approximately cylindrical vortex chamber 16, a spray water inlet tube part 17 for supplying spray water to the chamber 16 in its tangential direction, a mortar-shaped contraction part 18 the inside diameter of which is contracted gradually toward one end of the central axis X of the chamber 16, and an ejection port 19 which is opened at the end of the contraction part 18 to be concentric with the chamber 16 and ejects spray water in the shape of a hollow cone, the end surface 20 of the chamber 16 on the opposite side of the ejection port 19 in the central axis direction is formed spherically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a spray nozzle.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a feed water-steam system in a boiler, wherein 1 is a economizer, 2 is a furnace formed of furnace wall tubes, 3 is a primary superheater and a plate superheater. And a plurality of superheaters, such as a final superheater, 4 is a steam turbine,
The boiler feedwater is heated through the economizer 1 and the furnace 2 to form steam, and the steam is further superheated in a plurality of superheaters 3 to become superheated steam, guided to the steam turbine 4, and power is generated. ing.

In this type of boiler, a rated output is always obtained in the steam turbine 4 and the steam turbine 4 is protected in order to protect the steam turbine 4.
Is required to be maintained at a required temperature (for example, about 580 ° C.), and the temperature of the superheated steam is controlled by providing a superheat reducer 5 and spraying the superheated steam with water. .

[0004] The superheat reducing device 5 is provided at a required position of a steam pipe 6 for connecting a plurality of superheaters 3, which branches off from the middle of a water supply pipe 7 on the upstream side of the economizer 1 and has a spray nozzle 8 (see FIG. 4), a flow control valve 10 is provided in the middle of the spray pipe 9, and the inlet pipe 1 is connected to the inlet pipe 11 of the steam turbine 4.
1 is provided with a temperature detector 13 for detecting the temperature 12 of the superheated steam flowing through the inside 1, and an opening degree command for maintaining the temperature 12 of the superheated steam detected by the temperature detector 13 at a predetermined required temperature. It has a configuration provided with a control device 15 that outputs 14 to the flow control valve 10.

Conventionally, as shown in FIGS. 4 and 5, a spray nozzle 8 in the superheat reducer 5 has a generally cylindrical spiral chamber 16 and spray water tangential to the spiral chamber 16. A spray water inlet pipe portion 17 to be fed in, a mortar-shaped throttle portion 18 formed so that the inner diameter is gradually narrowed toward one end of the spiral chamber 16 in the central axis X direction, and a spiral chamber at an end of the throttle portion 18. 16 and an injection port 19 which is opened so as to be substantially concentric and injects spray water in a hollow conical shape.

In the boiler shown in FIG. 3, when the superheated steam is guided to the steam turbine 4, the temperature detector 13 detects the temperature 12 of the superheated steam flowing through the inlet pipe 11 of the steam turbine 4. An opening command 14 is output from the control device 15 to the flow control valve 10 so that the temperature 12 of the superheated steam detected by the temperature detector 13 is maintained at a predetermined required temperature, and the opening of the flow control valve 10 is adjusted. A part of the boiler feed water is supplied from a part of the feed pipe 7 on the upstream side of the economizer 1 to the spray nozzle 8 through the spray pipe 9.
Led to.

In the spray nozzle 8, as shown in FIGS. 4 and 5, spray water is sent from a spray water inlet pipe portion 17 to a spiral chamber 16 in a tangential direction thereof.
The spray water forms a swirling flow in the swirl chamber 16, is throttled by the throttle unit 18 and accelerated, and is injected into a hollow cone from the injection port 19, and is effectively mixed with superheated steam flowing through the steam pipe 6. The superheated steam is effectively cooled by the spray water.

[0008]

By the way, in the case of the superheat reducing device 5 as shown in FIG. 3, the main system of superheated steam guided to the steam pipe 6 through the economizer 1, the furnace 2 and the superheater 3 is provided. Spray pipe 9 from upstream side of economizer 1 so as to be parallel
Is branched and joined to the steam pipe 6. Therefore, in order to spray the spray water to the steam pipe 6, at least the total pressure loss on the spray pipe 9 side is smaller than the total pressure loss on the main system side. There is a need to.

The total pressure loss of the spray pipe 9 is determined by the pressure loss of the spray pipe 9 itself and the flow control valve 1.
Since the pressure loss at zero and the pressure loss at the spray nozzle 8 are the sum, if the pressure loss at the spray nozzle 8 is small, the pressure loss at the flow control valve 10 can be increased by that much, The adjustment range of the flow control valve 10 is widened, and therefore, it is preferable that the nozzle differential pressure ΔP (= P ₁ −P ₂ ) corresponding to the pressure loss of the spray nozzle 8 is as small as possible.

However, in the case of the conventional spray nozzle 8 as shown in FIGS. 4 and 5, the end face 20 on the side opposite to the injection port 19 in the center axis X direction in the spiral chamber 16 has a flat shape. However, the nozzle differential pressure ΔP becomes large, and the control width of the flow rate control valve 10 provided on the upstream side of the spray nozzle 8 becomes narrow, so that the temperature control range of the superheated steam becomes narrow, resulting in poor controllability. .

The relationship between the spray water amount Q and the nozzle differential pressure ΔP in the conventional spray nozzle 8 as shown in FIGS. 4 and 5 has a tendency shown by a broken line in FIG.

In view of the above circumstances, the present invention provides a spray nozzle capable of reducing the nozzle differential pressure and widening the control range of a flow control valve provided upstream of the spray nozzle to improve controllability. What you want to do.

[0013]

According to the present invention, there is provided a swirl chamber having a substantially cylindrical shape, a spray water inlet pipe for supplying spray water to the swirl chamber in a tangential direction, and one end of the swirl chamber in a central axis direction. A mortar-shaped throttle portion formed so that the inner diameter is gradually narrowed toward, and an injection port that is opened at an end of the throttle portion so as to be substantially concentric with the spiral chamber and that sprays spray water in a hollow conical shape. The spray nozzle according to the present invention is characterized in that the end face on the side opposite to the injection port in the direction of the central axis in the spiral chamber is formed into a spherical surface.

In the above-mentioned spray nozzle, when the inside diameter of the injection port is d, the radius of the spherical surface formed on the end face on the side opposite to the injection port in the center axis direction in the spiral chamber is substantially equal to d, and the spherical surface is formed. It is effective to set a center on the center axis of the swirl chamber shifted from the intersection of the center axis of the spray water inlet pipe section and the center axis of the swirl chamber by 0.1d to 0.2d toward the injection port side. is there.

According to the above means, the following effects can be obtained.

As described above, when the end surface on the side opposite to the injection port in the center axis direction in the spiral chamber is formed into a spherical surface, the nozzle differential pressure is reduced, and the adjustment width of the flow control valve provided upstream of the spray nozzle is increased. Good controllability.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an embodiment of the present invention. In the drawing, portions denoted by the same reference numerals as those in FIGS. 3 to 5 represent the same components, and the basic configuration is shown in FIGS. 5 is the same as the conventional one shown in FIG. 5, but the feature of the illustrated example is that, as shown in FIG.
The point is that the end face 20 on the side opposite to the injection port 19 in the direction is formed as a spherical surface.

In the illustrated example, when the inner diameter of the injection port 19 is d, the radius of the spherical surface formed on the end face 20 on the side opposite to the injection port 19 in the center axis X direction in the spiral chamber 16 is substantially d. The center of the spherical surface is set equal to the center axis Y of the spray water inlet pipe 17 and the center axis X of the spiral chamber 16.
The point C is on the center axis X of the spiral chamber 16 shifted from the intersection O of the spiral chamber 16 toward the injection port 19 by 0.1d to 0.2d.

Next, the operation of the illustrated example will be described.

As described above, when the end face 20 on the side opposite to the injection port 19 in the direction of the central axis X in the spiral chamber 16 is formed into a spherical surface, the nozzle differential pressure ΔP becomes small, and the flow rate adjustment provided on the upstream side of the spray nozzle 8 is performed. The adjustment range of the valve 10 is widened, the temperature control range of the superheated steam is widened, and the controllability is improved.

Incidentally, the relationship between the spray water amount Q and the nozzle differential pressure ΔP in the spray nozzle 8 of the illustrated example is shown in FIG.
It shows the tendency as shown by the solid line, and the nozzle differential pressure Δ
It can be seen that P has become smaller.

In this way, the nozzle pressure difference ΔP can be reduced, the control range of the flow control valve 10 provided upstream of the spray nozzle 8 can be widened, and the temperature control range of the superheated steam can be widened, thereby improving controllability. Can be achieved.

It should be noted that the spray nozzle of the present invention is not limited to the illustrated example described above, but may be applied to other than the overheat reducer. Of course, changes can be made.

[0025]

As described above, according to the spray nozzle of the present invention, the nozzle differential pressure can be reduced,
An excellent effect that the controllability can be improved by widening the adjustment range of the flow control valve provided on the upstream side of the spray nozzle can be achieved.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an example of an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a spray water amount and a nozzle differential pressure in an example of an embodiment of the present invention, and a relationship between a spray water amount and a nozzle differential pressure in a conventional example.

FIG. 3 is an overall schematic configuration diagram illustrating an example of a feedwater-steam system in a boiler.

FIG. 4 is a side sectional view of a conventional example.

FIG. 5 is a view taken in the direction of arrows VV in FIG. 4;

[Explanation of symbols]

 Reference Signs List 5 Superheat reducer 6 Steam pipe 8 Spray nozzle 9 Spray pipe 10 Flow control valve 16 Spiral chamber 17 Spray water inlet pipe section 18 Throttle section 19 Injection port 20 End face C point O Intersection X Center axis Y Center axis d Inner diameter

Claims (2)

[Claims] 1. A swirl chamber having a substantially cylindrical shape, a spray water inlet pipe for feeding spray water tangentially to the swirl chamber, and an inner diameter gradually narrowed toward one end of the swirl chamber in a central axis direction. A spray nozzle comprising a mortar-shaped narrowed portion formed on the end of the narrowed portion, and an opening which is opened at the end of the narrowed portion so as to be substantially concentric with the swirl chamber and injects spray water into a hollow conical shape. A spray nozzle characterized in that an end face on the side opposite to the injection port in the center axis direction in the room is formed as a spherical surface. 2. When the inner diameter of the injection port is d, the radius of the spherical surface formed on the end face on the side opposite to the injection port in the center axis direction in the spiral chamber is substantially equal to d, and the center of the spherical surface is 2. The spray nozzle according to claim 1, wherein a point on the center axis of the swirl chamber is shifted from the intersection of the center axis of the spray water inlet pipe portion and the center axis of the swirl chamber toward the injection port by 0.1d to 0.2d.