JP2929878B2 - Drain inflow shock prevention device for feed water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drain inflow impact prevention device for preventing impact of a drain inflow portion of a feed water heater for heating water supplied to a boiler of a thermal power plant.

[0002]

2. Description of the Related Art A feed water heater heats feed water to a boiler, and generally uses steam extracted as part of the expansion process of a turbine as a heat source. Among the feed water heaters, those that flow steam through the heat transfer surface and feed water into the tubes, such as a multi-tube heat exchanger, are called surface type feed water heaters.
FIG. 5 is a longitudinal sectional view of a conventional feed water heater. In FIG. 5, a plurality of heating tubes 2 each including a straight tube portion 2a and a curved tube portion 2b bent in a U-shape are accommodated in the body 1 through a support plate (not shown). The inside of the body 1 is divided into an upper water chamber and a lower water chamber. Steam extracted from the turbine is supplied into the fuselage 1 from a heating steam inlet 5 at the upper part of the fuselage, comes into contact with the heating pipe 2, is condensed, and is discharged from the heating steam outlet 6. On the other hand, the water supply enters the lower water chamber through the water supply inlet 7 below the pipe side head, exchanges heat with the steam through the heating pipe 2 and is heated to reach the upper water chamber, and from the upper water chamber to the water supply outlet 8
Is sent to the drain inlet 3 of the feed water heater of the next stage.
The feedwater heated by the feedwater heaters connected in multiple stages as described above is supplied to the boiler.

[0003] The heating steam of the feed water heater is internally heat-exchanged into saturated water, and is led from the drain outlet to the drain inlet 3 of the feed water heater on the lower pressure side via a pipe. FIG.
It is a VI-VI sectional view. The drain inlet 3 is provided on a side surface of the body 1. The drain flowing from the drain inlet 3 evaporates due to a pressure drop at the drain inlet 3 and becomes a two-phase flow to cause a flash. This flash causes erosion of the heating pipe 2 of the feed water heater. Conventionally, an impact baffle 4 facing the drain inlet 3 is provided inside the drain inlet 3 of the feed water heater, and the heater 2 is provided by a drain flush.
Erosion was prevented.

[0004]

In the conventional impact baffle 4, since the space at the drain inflow portion of the feed water heater is narrow,
The impact baffle 4 could reduce the impact, but could not prevent the drain from scattering. Also, the impact baffle 4
Drain flowing downward from the pipe may scatter the drain flowing through the bottom of the body of the feed water heater, causing an impact on the heating pipe and damaging the heating pipe.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a drain inflow impact preventing device for a feed water heater which has a simple structure and can prevent an impact on the heater due to drain flowing from a drain inlet.

[0006]

SUMMARY OF THE INVENTION In a feed water heater for feeding water to a boiler through a heating pipe for heating, a body of the feed water heater is extended toward a curved pipe portion side of the heating pipe, and the bending of the body is performed. A drain inlet disposed near the center of the lid that covers the end on the tube side, and an impact baffle plate vertically mounted in the lid and facing the drain inlet are provided, and the impact baffle plate and the heating pipe are provided. The above object is achieved by setting the distance between the curved baffle section and the distance between the impact baffle plate and the center of the drain inlet to be about four times.

Further, if a straightening plate fixed to the bottom of the lid of the body and extending upward between the impact baffle plate and the curved tube portion of the heating tube is disposed, it is preferable to prevent the drain from blowing up. is there.

In addition, in a feed water heater provided with a submerged type drain cooling section, the body of the feed water heater is extended toward the curved pipe side of the heating pipe. A drain inlet disposed near the center of a lid that covers an end of the body on the curved pipe side side, and an impact baffle vertically mounted in the lid and opposed to the drain inlet, wherein the impact baffle is provided. The above-mentioned object is achieved by making the distance between the impact baffle plate and the center of the drain inlet about four times the distance between the impact baffle plate and the center of the drain inlet.

Further, in a feed water heater provided with a submerged drain cooling unit, a flow straightening plate fixed to the bottom of the body lid and extending upward between the impact baffle plate and the curved tube portion of the heating tube is disposed. This is suitable for preventing the drain from blowing up.

[0010]

In the present invention, the body of the feed water heater is extended to the curved pipe side, and the drain inlet disposed near the center of the lid covering the end of the body on the curved pipe side, and vertically into the lid. Attached, providing a drain inlet and an opposing impact baffle,
The space on the curved tube side of the fuselage is widened, and the distance between the impact baffle and the curved tube of the heating tube is approximately four times the distance between the impact baffle and the center of the drain inlet, and the drain flows in from the rear of the fuselage. Then, the steam flowing from the drain inlet has a high flow rate due to the flash state, but there is an interval before reaching the curved pipe portion, so that the speed is reduced and the impact on the heating pipe is reduced.

In the present invention, a flow straightening plate fixed to the bottom of the lid of the body and extending upward between the impact baffle plate and the curved tube portion of the heating tube is disposed, and the flow velocity is reduced by the impact baffle plate. The drain is rectified by the rectifying plate, and the drain can be prevented from blowing up along the bottom of the body.

Further, in the present invention, the body of the feed water heater provided with the submerged drain cooling unit is extended to the curved pipe side, and is disposed near the center of the lid covering the end of the body on the curved pipe side. A drain baffle and a shock baffle vertically attached to the lid and facing the drain brace are provided to increase the space on the curved tube side of the fuselage, and to provide a space between the baffle and the curved tube of the heating tube. The distance between the impact baffle and the center of the drain inlet is about 4
With the drain flowing from the back of the fuselage, the steam flowing from the drain inlet has a fast flow rate due to the flash state, but there is an interval before it reaches the curved pipe, so the speed is reduced and the impact on the heating pipe is reduced. You.

Further, according to the present invention, there is provided a flow straightening plate fixed to a bottom of a lid of a body of a feed water heater having a submerged drain cooling portion and extending upward between an impact baffle plate and a curved tube portion of a heating tube. The drain whose flow velocity has been reduced by the impact baffle plate is rectified by the rectifier plate, the water level of the drain cooling part in the fuselage is controlled by the control device, and the rectified drain flows, so the water level is stable, The feed water heater can be operated safely.

[0014]

Embodiment 1 FIG. 1 is a longitudinal sectional view showing an embodiment of a feed water heater provided with a drain inflow impact prevention device according to the present invention, and FIG. 2 is an enlarged view of a portion II in FIG. 1 and 2, the same parts as those in FIGS. 5 and 6 are denoted by the same reference numerals. In FIG. 1, a body 1, a heating pipe 2, a heating steam inlet 5, a heating steam outlet, a water supply inlet 7, and a water supply outlet 8 are the same as those in the related art, and thus description thereof is omitted.
1 and 2 is arranged near the center of a lid 9 that extends the curved pipe portion 2b side of the heating pipe 2 of the body 1 of the feed water heater and covers the end portion of the fuselage 1 on the curved tube section 2b side. A drain baffle 4 and a shock baffle 4 vertically mounted in the lid 9 and opposed to the drain baffle 3, and the distance A between the baffle 4 and the curved tube portion 2 b is defined by the impact baffle 4 and the drain baffle 3. Is about four times the distance B from the center. Further, a flow straightening plate 10 fixed to the bottom of the lid 9 and extending upward between the impact baffle plate 4 and the curved tube portion 2b of the heating tube is disposed. When the two-phase flow drain enters the feed water heater from the drain inlet 3, it enters the feed water heater through a gap between the lid 9 and the impact baffle 4, which is blocked by the impact baffle 4. Since this flow is in a flush state, it has a large flow velocity. However, the distance A between the impact baffle 4 and the curved tube portion 2b is
The distance between the drain and the curved tube portion 2b of the heating tube is about four times, so that the flow velocity is reduced before the drain reaches the heating tube 2.
Further, since the rectifying plate 9 is attached between the impact baffle plate 4 and the curved pipe portion 2b, the drain flowing through the bottom of the body 1 is rectified by the rectifying plate 9, so that the drain is discharged by the flow velocity from the impact baffle plate 4. You won't be blown up. As a result, it is possible to sufficiently prevent the drain impact applied to the heating tube 2.

Embodiment 2 FIG. 3 is a longitudinal sectional view showing an embodiment of a feed water heater having a submerged drain cooling unit provided with a drain inflow impact prevention device of the present invention, and FIG. 4 is an enlarged view of an IV section in FIG. is there. 3 and 4, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals. 1
Reference numeral 2 denotes a drain cooling unit surrounding plate. 3 and 4 show an example in which a feed water heater having a submerged drain cooling unit is provided with the drain inflow impact prevention plate of the present invention. In the drain cooling unit 11, the water level is controlled so that the water level in the body 1 becomes a set value by adjusting the opening of a steam outlet valve (not shown) connected to the heated steam outlet 6. In this example, the body 1 of the feed water heater is extended to the curved pipe portion 2b side of the heating pipe 2, and the body 1
A drain inlet 3 disposed near the center of the lid 7 covering the end on the side of the curved pipe portion 2b, and vertically mounted in the lid 9;
An impact baffle 4 facing the drain inlet 3 is provided, and the distance A between the impact baffle 4 and the curved tube portion 2b of the heating tube is set to about 4 which is the distance between the impact baffle 4 and the curved tube portion 2b of the heating tube. Since it was doubled,
The flow rate is reduced before the drain reaches the heating tube 2.
Further, a rectifying plate 10 is provided between the impact baffle plate 4 and the curved tube portion 2b.
Is attached, the drain flowing through the bottom of the body 1 is rectified by the rectifying plate 10. Therefore, the water level of the drain cooling unit 11 in the body 1 is kept substantially constant, and the feed water heater can be operated safely.

[0016]

According to the present invention, a drain inlet is provided in the lid at the rear of the body, and the drain flows in from the rear of the body,
Since an impact baffle is provided at the drain inlet to increase the space, the speed of the flow of the drain in the flash state is reduced, so that the impact applied to the heating tube can be reduced. According to the present invention, since only the body is made longer, the weight increase can be reduced as compared with the case where the drain inlet is provided beside the body as in the conventional case.

Further, according to the present invention, a rectifying plate is provided between the impact baffle in the fuselage and the curved tube portion to rectify the drain passing through the impact baffle, so that the drain travels along the bottom of the fuselage. It can prevent blowing up.

Further, if the water-supply heater having the submerged drain cooling unit is provided with the impact prevention plate and the rectifying plate of the present invention, the fluctuation of the water level of the drain cooling unit in the body can be reduced, and the stable operation of the water heater can be achieved. Can be.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a feed water heater provided with a drain inflow impact prevention device according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view of a part II in FIG.

FIG. 3 is a longitudinal sectional view of a feed water heater provided with a drain inflow impact prevention device according to Embodiment 2 of the present invention.

FIG. 4 is an enlarged view of a part IV in FIG. 3;

FIG. 5 is a longitudinal sectional view of a feed water heater provided with a conventional drain inflow impact prevention device.

FIG. 6 is a view showing a part of a section taken along line VI-VI of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 Heating pipe 2a Straight pipe part 2b Curved pipe part 3 Drain inlet 4 Impact baffle plate 5 Heating steam inlet 6 Heating steam outlet 7 Water supply inlet 8 Water supply outlet 9 Lid 10 Straightening plate 11 Drain cooling unit

Claims (4)

(57) [Claims] 1. A feed water heater for feeding water to a boiler through a heating pipe to heat the feed water, wherein a body of the feed water heater is extended to a curved pipe side of the heating pipe, and a body of the feed body is extended to a curved pipe side of the heating pipe. A drain inlet disposed near the center of the lid covering the end, and an impact baffle vertically attached to the lid and opposed to the drain inlet are provided, and the impact baffle and a curved tube portion of the heating tube are provided. A distance between the impact baffle plate and the center of the drain inlet is about four times as large. 2. A drain inflow prevention device for a feed water heater according to claim 1, further comprising a rectifying plate fixed to the bottom of the body lid and extending upward between the impact baffle plate and the curved tube portion of the heating tube. A drain inflow prevention device for a feed water heater. 3. A feed water heater provided with a submerged-type drain cooling section, wherein the feed water to the boiler is passed through a heating pipe and heated, and a body of the feed water heater is extended to a curved pipe side of the heating pipe. A drain inlet disposed near the center of a lid that covers an end of the body on the curved pipe side side, and an impact baffle vertically mounted in the lid and opposed to the drain inlet, wherein the impact baffle is provided. A distance between the impact baffle plate and the center of the drain inlet is approximately four times a distance between the impact baffle plate and the center of the drain inlet. 4. A drain inflow prevention device for a feed water heater according to claim 3, wherein a flow straightening plate fixed to the bottom of the body lid and extending upward between the impact baffle plate and the curved tube portion of the heating tube is disposed. A drain inflow prevention device for a feed water heater.