JP2012202311A - Turbine bypass pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deposition of scales or the like on a valve provided on a turbine bypass pipe.SOLUTION: A turbine bypass pipe 1 is branched from a main steam pipe 2 for supplying steam from a steam source to a turbine. The turbine bypass pipe 1 includes an upward pipe line 4 directed upwardly from a branch 3 from the main steam pipe 2, a valve 5 for opening and closing the turbine bypass pipe in a pipe line in the middle of the upward pipe line 4 or a pipe line downstream of the upward pipe line 4, and a resistor 7 for imparting the resistance to the fluid in the pipe line between the valve 5 and the branch.

Description

  The present invention relates to a turbine bypass pipe applied to a steam pipe for supplying steam from a steam source of a power plant to a turbine.

For example, there is a turbine bypass pipe as a pipe that bypasses the steam without flowing it to the turbine when the thermal power plant is started and stopped. The turbine bypass pipe is a pipe branched from the middle of the main steam pipe that introduces steam from a steam generation source such as a boiler into the turbine, and does not guide surplus steam to the turbine, for example, bypasses it to the condenser of the turbine. .
The turbine bypass valve is a valve that controls the flow rate of surplus steam flowing in the turbine bypass pipe, and is gradually closed with the output of a steam generation source such as a boiler.

  Patent Document 1 describes a main steam pipe provided with a bypass pipe and a bypass valve for the purpose of suppressing pressure fluctuations in the main steam pipe when the output is increased in a boiling water nuclear power plant.

Japanese Patent No. 4551875

By the way, the steam generated in the boiler and flowing in the main steam pipe includes a steam oxidation scale (hereinafter referred to as scale) grown and separated on the inner face of the pipe. On the other hand, since the turbine bypass pipe is not used except when the power plant is started and stopped, during the normal operation of the power plant, there is no flow in the pipe, and the turbine bypass pipe is stagnant.
At this time, scale and dust may flow from the main steam pipe to the turbine bypass pipe. If the scale or dust accumulates on the turbine bypass valve, there is a problem in that it adversely affects the operation of the turbine bypass valve.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a turbine bypass pipe that prevents scales and the like from accumulating on a turbine bypass valve provided in the turbine bypass pipe. .

In order to achieve the above object, the present invention provides the following means.
The turbine bypass pipe of the present invention is a turbine bypass pipe branched from a main steam pipe for supplying steam from a steam source to the turbine, and the turbine bypass pipe is upwardly directed upward from a branch portion with the main steam pipe. Between the pipe, a valve that opens and closes the turbine bypass pipe in the middle of the upward pipe or downstream of the upward pipe, and between the valve and the branch portion, fluid in the pipe It is provided with the resistor which gives resistance.

  According to the said structure, the flow in a pipe line is suppressed by a resistor, and it can prevent that the scale etc. which flowed into the turbine bypass piping from the branch part reach a turbine bypass valve.

Moreover, it is preferable that the said resistor is the bending of the said pipe line.
According to the above configuration, scales and the like are accumulated at the bend and do not reach the turbine bypass valve, so that scales and the like are not accumulated on the turbine bypass valve.

Moreover, it is preferable that the said resistor is a narrow part provided in the said pipe line.
According to the said structure, since a scale etc. become difficult to pass a narrow part, it can prevent that a scale etc. reaches a turbine bypass valve.

Moreover, it is preferable that the valve is located at a predetermined distance from the branch portion.
According to the said structure, a scale etc. becomes difficult to reach a turbine bypass valve, and it can prevent that a scale accumulates on a turbine bypass valve.

  The valve includes an inlet-side channel, an outlet-side channel facing the direction intersecting with the inlet-side channel, and the outlet-side channel at an intersection of the inlet-side channel and the outlet-side channel. Between the extended portion extending to the opposite side of the downstream side, the closed side position that intersects with the inlet side flow channel, and the open position within the extended portion. Preferably, the valve body is provided with a pressure equalizing pipe that communicates one side of the valve body with the other side, and a resistance element is provided in the pressure equalizing pipe.

  According to the above configuration, even when the scale or the like enters the pressure equalizing pipe along with the steam, the scale or the like passes through the pressure equalizing pipe and hardly reaches the opposite side of the valve body.

  The valve includes an inlet-side channel, an outlet-side channel facing the direction intersecting with the inlet-side channel, and the outlet-side channel at an intersection of the inlet-side channel and the outlet-side channel. Between the extended portion extending to the opposite side of the downstream side, the closed side position that intersects with the inlet side flow channel, and the open position within the extended portion. And a pressure equalizing pipe that communicates one side of the valve body with the other side, and is provided on the outer periphery of the valve body and slides with the outlet-side flow path. It is preferable that a protruding portion that protrudes toward the extension portion is provided inside the surface.

  According to the said structure, the scale which penetrate | invaded into the extension part side of the valve main body via the pressure equalization pipe line becomes difficult to enter the sliding part between a valve and an exit side flow path by providing the protrusion part.

  The valve further includes an inlet-side channel, an outlet-side channel that extends in a direction intersecting the inlet-side channel, and the outlet-side channel at an intersection of the inlet-side channel and the outlet-side channel. Between the extended portion extending to the opposite side of the downstream side, the closed side position that intersects with the inlet side flow channel, and the open position within the extended portion. A pressure equalizing pipe that communicates one side of the valve body with the other side, a resistance element is provided in the pressure equalizing pipe, and the valve body It is preferable that a protrusion that protrudes toward the extension portion is provided on the inner periphery of the slide surface with the outlet-side channel.

  According to the above configuration, even when the scale or the like enters the pressure equalizing pipe along with the steam, the scale or the like passes through the pressure equalizing pipe and hardly reaches the opposite side of the valve body. Even when a scale or the like has entered the opposite side of the valve body, by providing the protrusion, the scale that has entered the extension part side of the valve body via the pressure equalizing conduit is between the valve and the outlet side flow path. It becomes difficult to enter the sliding part.

  According to the present invention, since the flow in the pipeline of the turbine bypass pipe is suppressed by the resistor, the scale or the like flowing into the turbine bypass pipe from the branch portion can be prevented from reaching the turbine bypass valve.

It is the schematic of turbine bypass piping by 1st embodiment of this invention. It is a detailed sectional view of a turbine bypass valve by a first embodiment of the present invention, and is a view showing an open position of the turbine bypass valve. It is a figure which shows the closed position of the turbine bypass valve of FIG. It is the schematic of turbine bypass piping by 2nd embodiment of this invention. It is a detailed sectional view of a turbine bypass valve according to a third embodiment of the present invention.

(First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The turbine bypass pipe 1 according to the present embodiment is applied to a thermal power plant, and is a pipe branched from a steam pipe that supplies steam from a steam source such as a boiler to a turbine.
As shown in FIG. 1, the turbine bypass pipe 1 is branched from the main steam pipe 2, and includes an upward pipeline 4 that extends upward from the branch portion 3 of the main steam pipe 2, and an upward pipeline 4. A turbine bypass valve 5 that is provided at the upper end of the upstream pipeline 4 downstream and opens and closes the turbine bypass pipe 1 and a horizontal pipeline 6 that is a pipeline downstream of the turbine bypass valve 5 are provided.

The main steam pipe 2 is a pipe that guides steam from the boiler to the turbine. The turbine bypass pipe 1 is a pipe that guides steam from the boiler to the condenser when the thermal power plant is started and stopped. The turbine bypass valve 5 is a valve that adjusts the flow rate of the steam flowing through the turbine bypass pipe 1 by opening and closing.
An interval of 2 m is provided between the branch portion 3 and the turbine bypass valve 5.

  In the middle of the upward pipeline 4, a crank portion 7 that is a curve of the upward pipeline 4 is provided. The crank portion 7 is provided in the middle of the upward pipeline 4 directed upward, a first elbow 8 that bends the flow of the upward pipeline 4 in the horizontal direction by 90 °, and a relatively short connected to the first elbow 8. It is comprised from the horizontal piping 9, and the 2nd elbow 10 which is provided in the downstream end of the horizontal piping 9, and bends the flow of the horizontal piping 9 90 degrees upwards.

Next, details of the turbine bypass valve 5 will be described.
As shown in FIG. 2, the turbine bypass valve 5 includes an upward pipeline 4 that is an inlet-side channel, a horizontal pipeline 6 that is an outlet-side channel that extends in a direction intersecting the upward pipeline 4, The valve mechanism 12 is provided at the intersection 11 between the counter pipe 4 and the horizontal pipe 6.
The intersection 11 is provided with an extension 13 that extends the horizontal pipe 6. The extension 13 is formed such that its central axis coincides with the central axis of the horizontal pipe 6 and its inner diameter is the same as the inner diameter of the horizontal pipe 6. A wall 14 is formed at the end of the extension 13 and closed. The valve mechanism 12 is installed along the extension 13 and the horizontal pipe 6.

  The valve mechanism 12 includes a valve body 15 and a valve rod 16, and the valve body 15 is moved in the direction along the central axis of the horizontal pipe 6 and the extension portion 13, so that the open position (FIG. 2) and the closed position are (FIG. 3) can be taken.

  The valve body 15 has a cylindrical main body portion 17 having an outer diameter slightly smaller than the inner diameters of the horizontal pipe line 6 and the extension portion 13, and an outer peripheral surface of the main body portion 17 extending downstream with a predetermined thickness. It has a cylindrical skirt 18. The total length of the main body portion 17 and the skirt portion 18 in the axial direction (the direction along the horizontal pipeline 6) is set to be longer than the inner diameter of the upward pipeline 4.

  The valve body 15 is provided with a protrusion 24. The protruding portion 24 is an annular portion in which the outer peripheral surface of the main body portion 17 has a predetermined thickness and protrudes in the direction opposite to the downstream side.

  The body portion 17 of the valve body 15 is provided with two pressure equalization pipes 19 that penetrate in the central axis direction and communicate the upstream and downstream flow paths of the valve body 15. The pressure equalizing pipe 19 is provided concentrically around the central axis of the valve body 15. Inside each of the pressure equalizing pipes 19, a filter 23 that is a resistance element with respect to the scale is disposed so as to be orthogonal to the axial direction of the pressure equalizing pipes 19. The filter 23 is formed of a nonwoven fabric made of nylon fiber or the like.

  The valve stem 16 is connected to the surface of the valve body 15 opposite to the skirt portion 18 of the main body portion 17 and extends to the outside from a valve stem hole 20 formed in the wall portion 14. Etc. are connected to an actuator (not shown). It is preferable that a seal member such as an O-ring is interposed between the valve stem 16 and the valve stem hole 20.

  A net 22 is provided in a connection hole 21 provided in the horizontal pipe 6 at an intersection 11 between the upward pipe 4 and the horizontal pipe 6. The net 22 has sufficient mesh (distance between adjacent yarns) so that the steam flows smoothly.

Next, the effect | action of the turbine bypass piping 1 of this embodiment is demonstrated.
The turbine bypass valve 5 is disposed in the open position as shown in FIG. 2 at a stage where the output at the start of the thermal power plant is in the middle of increase and at a stage where the output at the time of the shutdown of the thermal power plant is in the middle of decrease. The steam is guided to the turbine bypass pipe 1 branched from the main steam pipe 2. This bypasses the steam to the condenser of the turbine.

On the other hand, after starting the thermal power plant, during normal operation, the turbine bypass valve 5 is disposed in the closed position as shown in FIG. The steam is guided to the main steam pipe 2 and the turbine bypass pipe 1 has no steam flow.
Further, when the turbine bypass valve 5 is moved from the closed position to the open position (or when moved in the opposite direction), the movement is smoothly performed by the steam passing through the pressure equalizing pipe 19.

  According to the above embodiment, even when scale or dust flows into the turbine bypass pipe 1 from the branch portion 3, the flow in the pipeline is suppressed by the crank portion 7, and scale or dust accumulates on the crank portion 7. In addition, since it becomes difficult to reach the turbine bypass valve 5, it is possible to prevent the scale or dust from accumulating on the turbine bypass valve 5.

Further, when the turbine bypass valve 5 is in the open position (when steam is flowing in the turbine bypass pipe 1), scale or dust may pass through the crank portion 7 and reach the horizontal pipeline 6. . At this time, when the turbine bypass valve 5 is moved to the closed position, the scale or dust enters the pressure equalizing pipe 19 together with the steam.
According to the above-described embodiment, even in such a case, the scale does not reach the opposite side of the valve body 15 by providing the filter 23 in the pressure equalizing pipe 19.

  Further, when the turbine bypass valve 5 is moved to the closed position or the like, the scale passes through the pressure equalizing pipe 19 and enters the opposite side of the valve body 15. Is provided, it becomes difficult for the scale to enter the sliding portion between the valve body 15 and the horizontal pipe line 6 or the extension portion 13.

  In addition, since the distance between the branch portion 3 and the turbine bypass valve 5 is 2 m, the scale is difficult to reach the turbine bypass valve 5 and the scale is prevented from accumulating on the turbine bypass valve 5. Can do.

  Next, other embodiments will be described with reference to the accompanying drawings, but the same or similar members and parts as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted. A different configuration will be described.

(Second embodiment)
As shown in FIG. 4, the turbine bypass pipe 1 </ b> B in the second embodiment is provided with an orifice 25 instead of the crank portion 7 (see FIG. 1) of the first embodiment. The orifice 25 forms a narrow portion in the middle of the upward pipeline 4 by forming a throttle on the inner diameter of the pipeline.

According to the above-described embodiment, the flow in the turbine bypass pipe 1 is suppressed by the orifice 25, and the scale does not easily pass through the portion where the orifice 25 is provided, so that the scale can be prevented from rolling up.
In the present embodiment, a steam flow resistor may be provided by providing a wire mesh or a butterfly valve instead of the orifice 25.

(Third embodiment)
As shown in FIG. 5, the pressure equalizing pipe 19 </ b> C of the turbine bypass pipe according to the third embodiment has an inner diameter smaller than that of the pressure equalizing pipe 19 as in the first embodiment. On the other hand, the filter 23 is not provided in the pressure equalizing pipe 19C.
The inner diameter of the pressure equalizing pipe 19C of the third embodiment is formed so that the ratio (D / L) of the inner diameter D and the length L of the pressure equalizing pipe 19C is 1/10 or less.

  According to the embodiment, by reducing the inner diameter of the pressure equalizing pipe 19C, the amount of scale and dust passing through the pressure equalizing pipe 19C can be reduced. Further, by reducing the inner diameter, the flow resistance in the pressure equalizing pipe 19C can be increased, the flow velocity inside the pressure equalizing pipe 19C can be reduced, and the flow of scale and the like can be suppressed.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the number of pressure equalizing pipes 19 is not limited to two, and the number can be appropriately changed in consideration of resistance when the valve body 15 is moved.

  Moreover, although the said embodiment demonstrated the example which applied the turbine bypass piping to the thermal power plant, the turbine bypass piping of this invention is not restricted to a thermal power plant, A turbine is generated with the steam generated by steam sources, such as a nuclear power plant. It can be applied to various power plants that generate electricity by turning.

  Moreover, in the said embodiment, although the turbine bypass valve 5 is provided in the upper end of the upward pipeline 4, it is not restricted to this, If it is downstream of resistors, such as the crank part 7, an upward pipeline It is good also as a structure provided in the middle of 4 or the middle of the horizontal pipe line 6.

DESCRIPTION OF SYMBOLS 1 ... Turbine bypass piping, 2 ... Main steam piping, 3 ... Branch part, 4 ... Upward pipe line, 5 ... Turbine bypass valve (valve), 7 ... Crank part (resistor, bending), 15 ... Valve body, 19 ... pressure equalizing pipe, 23 ... filter (resistance element), 24 ... protrusion, 25 ... orifice (narrow part).

Claims (7)

A turbine bypass pipe branched from a main steam pipe for supplying steam from a steam source to the turbine,
The turbine bypass pipe is an upward pipe line directed upward from a branch portion with the main steam pipe;
A valve that opens and closes the turbine bypass pipe in the middle of the upward pipeline or in a pipeline downstream of the upward pipeline;
A turbine bypass pipe comprising a resistor that provides resistance to a fluid in a pipe line between the valve and the branch portion.   The turbine bypass pipe according to claim 1, wherein the resistor is a bend of the pipeline.   The turbine bypass pipe according to claim 1, wherein the resistor is a narrow portion provided in the pipeline.   The turbine bypass pipe according to any one of claims 1 to 3, wherein the valve is located at a predetermined distance from the branch portion. The valve is
An inlet-side flow path;
An outlet-side flow path that goes in a direction intersecting the inlet-side flow path;
At the intersection of the inlet-side channel and the outlet-side channel, an extension that extends the outlet-side channel to the side opposite to the downstream side,
A valve body that is movably provided in the outlet-side flow path and is movable between a closed position intersecting the inlet-side flow path and an open position in the extension portion;
5. The valve body according to claim 1, further comprising a pressure equalizing pipe that communicates one side of the valve body with the other side, and a resistance element is provided in the pressure equalizing pipe. The turbine bypass piping according to item 1. The valve is
An inlet-side flow path;
An outlet-side flow path that goes in a direction intersecting the inlet-side flow path;
At the intersection of the inlet-side channel and the outlet-side channel, an extension that extends the outlet-side channel to the side opposite to the downstream side,
A valve body that is movably provided in the outlet-side flow path and is movable between a closed position intersecting the inlet-side flow path and an open position in the extension portion;
The valve body is provided with a pressure equalizing pipe that communicates one side of the valve body with the other side, and the outer periphery of the valve body, on the inside of the slide surface with the outlet-side channel, The turbine bypass pipe according to any one of claims 1 to 4, wherein a protruding portion that protrudes is provided. The valve is
An inlet-side flow path;
An outlet-side flow path that goes in a direction intersecting the inlet-side flow path;
At the intersection of the inlet-side channel and the outlet-side channel, an extension that extends the outlet-side channel to the side opposite to the downstream side,
A valve body that is movably provided in the outlet-side flow path and is movable between a closed position intersecting the inlet-side flow path and an open position in the extension portion;
The valve body is provided with a pressure equalizing pipe that communicates one side of the valve body with the other side, a resistance element is provided in the pressure equalizing pipe, and an outer periphery of the valve body, the outlet side flow The turbine bypass pipe according to any one of claims 1 to 4, wherein a protruding portion that protrudes toward the extension portion is provided on the inner side of the slide surface with the road.

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