JP2000002402A - Pressure loss follow-up type movable orifice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure loss follow-up type movable orifice which can conduct balance adjustment between the pressure loss at a unit body side of a boiler and the pressure loss at a spray water piping system side in the movable orifice which is applied to a water supply system of an electric power plant and capable of following and coping with the alteration of pressure loss of the system. SOLUTION: Fixing shafts and movable shafts are protrusively set at the end portions of a plurality of arched movable plates 2 and fitted to the holes in a tap plate 3 and the grooves on a rotary plate 4, thus constructing an orifice plate 1 by superposing the tap plate 3, the movable plates 2 and the rotary plate 4. When the rotary plate 4 is driven, the movable plates 2 are moved to vary the opening area of the orifice plate 1, thereby coping with the pressure alteration at an upstream and a downstream.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable orifice which is applied to a water supply system in a power plant and can respond to changes in pressure loss of the system.

[0002]

2. Description of the Related Art In a boiler for a thermal power plant, it is necessary to control the steam temperature of the boiler in order to keep the temperature of steam supplied to a steam turbine constant.

[0003] This temperature control is performed by installing a superheat reducer in the middle of a plurality of superheaters provided in the boiler, and injecting spray water to the steam side with the superheat reducer to lower the steam temperature. In general, a method of controlling the steam temperature at the boiler outlet so as to be kept constant is adopted.

A conventional device of this type will be described with reference to FIGS. As shown in the system diagram in FIG. 4, the removal of the spray water to be supplied to the superheat reducer 9 provided in the boiler,
When the water is taken out from the water supply pipe 10 at the boiler inlet in a branched form, water is supplied from the water supply pipe 10 to the boiler body via a not-shown economizer, and the pressure loss of the system from reaching the superheater not shown. (Δp) is the pressure loss of the spray water pipe that branches from the water supply pipe 10 to spray to the superheat reducer 9 and then reaches the superheat reducer 9 and the superheat reducer 9.
Must be smaller than the sum of the spray nozzle differential pressures at (Δp _s ).

When the load of the boiler unit is high, the flow rate flowing to the boiler main body side is large, and the pressure loss (Δ
p) is large and the pressure loss (Δp
There is no problem because _s ) is planned to be smaller than this.

However, when the load of the boiler unit is reduced, the flow rate on the boiler main body side is reduced, and the pressure loss (Δp _s ) of the spray water system is relatively increased. In some cases, a differential pressure for injecting spray water cannot be secured.

Therefore, in order to be able to inject spray water even at a low unit load,
A movable orifice 11 that becomes a resistance after the spray water system branches off from the water supply pipe 10 is provided so that a sufficient differential pressure can be secured in the spray water system even at a low load.

Since the movable orifice 11 is not necessary when the boiler unit is operated under a high load, conventionally, the movable orifice 11 has a structure in which a hole is formed in the valve body of the gate valve. When the unit is under high load, it is fully opened to prevent extra pressure loss, and when the unit is under low load, it is fully closed and used with small holes.
The movable orifice 11 that intentionally gives resistance is used.

The specific structure of the conventional movable orifice 11 is as shown in FIG. 3, in which an orifice plate 6, which is a main part, is disposed in a pipe of a water supply pipe, and is connected to the orifice plate 6 to move upward. A drive device 8 is connected to the extending valve stem 7, and the drive device 8 is configured to switch the orifice plate 6 between the inside and outside of the pipeline via the valve stem 7 in an on / off manner.

[0010]

In the conventional movable orifice constructed as described above, the fully open position removed from the pipeline as described above and the fully closed position housed in the pipeline (in this case, the fully closed position). The orifice is used with a small hole in which the flow path is formed). Therefore, when the movable orifice is used at low load, excessive resistance (pressure loss) may occur. In this case, the water head required for the boiler feed pump becomes excessive, and the pump power may be wasted.

For this reason, if an orifice capable of providing the minimum necessary resistance can be provided, it is possible to prevent such excessive boiler feedwater pump power from being consumed and to reduce the unit load. It is possible to contribute to the improvement of the plant efficiency and the reduction of auxiliary power at the time.

The present invention has been made in view of such a situation. The present invention follows a change in the situation of the plant, adjusts the pressure loss by changing the magnitude of the resistance as necessary, and reduces the pressure loss on the unit body side of the boiler. It is an object of the present invention to provide a movable orifice that can follow a pressure loss change and that can balance pressure loss on a spray water piping system side.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a fixed shaft protruding at one end of one surface of a curved plate having an arc shape and the other surface. A plurality of movable plates having a movable shaft protruding from the other end thereof, and a holding plate and a rotating plate each formed of a circular plate having an outer ring and an inner ring are provided, and the fixed shaft is provided on one of the holding plate and the rotating plate. A plurality of radial grooves for slidingly guiding the rotating shaft are provided on the other side, and the fixed shaft and the movable shaft are formed between the holding plate and the rotating plate by the holes and the grooves. And a plurality of movable plates are arranged in a circle to form an orifice plate, and the rotary plate is connected to a driving device for reciprocatingly rotating.

That is, according to the present invention, one end of one surface is fixedly positioned with respect to either the holding plate or the rotating plate by engagement of the fixed shaft with the hole, and the other surface is provided. A movable plate which is movable with respect to the other of the holding plate or the rotating plate by engagement of a rotating shaft and a groove with the movable plate. By rotating the rotating plate in one direction by a driving device in the orifice plate formed by arranging a plurality of circular shapes between the rotating shaft and the fixed shaft and the fixed position of the hole, the rotating shaft moves in the groove. Sliding relative movement, the diameter of the circular array of movable plates changes.

That is, each movable plate pivotally moves at the movable shaft side end about the fixed shaft, and the size of the circular shape formed by the arcuate inner surface of each movable plate changes, and the area of the circular shape is the same. To change the flow path area of the orifice plate, thereby continuously changing the resistance of the flow path.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS.

Reference numeral 2 denotes a movable plate composed of a bow-shaped curved plate. A fixed shaft 2a projects from one end of the front surface of the movable plate, and a rotating shaft 2b projects from the other end of the rear surface. Has been established.

Reference numeral 3 denotes a presser plate, which is formed by a donut-shaped plate defined by an outer ring 3b and an inner ring 3c. A plurality of presser plates are provided between the outer ring 3b and the inner ring 3c on a concentric circular locus. A hole 3a is formed, and the hole 3a is used to fit a fixed shaft 2a of the movable plate 2 to fix a connection position between the movable plate 2 and the holding plate 3.

Reference numeral 4 denotes a rotating plate, which is formed of a donut-shaped plate defined by an outer ring 4b and an inner ring 4c having the same diameter as the presser plate 3. The flat plate intermediate the outer ring 4b and the inner ring 4c has It corresponds to the position of the hole 3a of the holding plate 3, and
a, and the same number of grooves 4a extending in the radial direction are formed.
When the rotary plate 4 is rotated by the drive rod 4d, the movable shaft 2 is guided by sliding the rotary shaft 2b.
And the connecting position between the rotary plate 4 and the rotary plate 4 can be relatively moved.

A plurality of movable plates 2 are arranged on a circumferential track between the holding plate 3 and the rotary plate 4 by fitting the fixed shaft 2a and the hole 3a and the rotating shaft 2b and the groove 4a to each other. As shown in FIGS. 1A and 1B, an orifice plate 1 is formed.

A driving rod 4d provided on the outer race 4b of the rotating plate 4 is connected to a driving device 5, and the driving plate 5 is used as a driving source to rotate the rotating plate 4 in a circle as shown by an arrow in FIG. It has a structure that can reciprocate in the circumferential direction.

In the present embodiment configured as described above, when the difference between the pressure in the spray water supply line and the pressure at the spray water spray destination decreases at a low load of the unit, the driving device 5 rotates The movable plate 2 fixed to the rotated rotating plate 4 is rotated by rotating the plate 4.
The movable plate 2 is connected to the hole 3
a of the rotating plate 4 with the fixed shaft 2a inserted in
When the movable shaft 2b inserted in the movable plate 2 slides in the groove 4a, the opening (aperture) of the orifice plate 1 formed by the movable plate 2 changes in size as the rotary plate 4 rotates.

Due to the opening (throttle) of the orifice plate 1, the pressure at the upstream of the orifice causes a pressure difference with the downstream of the orifice due to the pressure loss generated by the throttle, and the rotation of the rotary plate 4, that is, the orifice plate 1
The pressure difference between the upstream side and the downstream side can be adjusted depending on the size of the opening, and a pressure difference without waste at each load can be obtained.

Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to such an embodiment.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

For example, in the above-described embodiment, a hole 3a is formed in the holding plate 3, a groove 4a is formed in the rotating plate 4, and the movable plate 2 is fixed to the holding plate 3, and Although it was described that it was relatively movable between,
The same result can be obtained by forming a groove in the holding plate 3 and forming a hole in the rotating plate 4, and it goes without saying that the present invention includes such a modification.

Further, by providing a pressure gauge downstream of the orifice plate 1 and monitoring the pressure, the opening of the orifice plate 1 can be automatically adjusted by interlocking with the pressure.

[0027]

As described above, according to the present invention, a fixed shaft is projected from one end of one surface of a curved plate having an arc shape and a movable shaft is projected from the other end of the other surface. Provided a plurality of movable plates, a holding plate and a rotating plate each constituted by a circular plate having an outer ring and an inner ring, and a hole for fitting the fixed shaft into one of the holding plate and the rotating plate is provided on a circumferential locus. Plural provided, the other provided with a plurality of radial grooves to slide and guide the rotating shaft, between the holding plate and the rotating plate, the fixed shaft and the movable shaft is fitted into the hole and the groove, and a plurality of movable plates are provided. An orifice plate is formed in a circular shape, and the rotary plate is connected to a reciprocatingly rotating drive device to form a movable orifice following the pressure loss change. One end of one surface is defined by a fixed shaft and a hole. Either the holding plate or the rotating plate Positioning is performed in a fixed manner with respect to,
A movable plate is used which is capable of moving the other end of the other surface with respect to the holding plate or the other one of the rotating plates by engagement of a rotation shaft and a groove, and the movable plate is In the orifice plate formed by arranging a plurality of circular orifices between the plate and the rotating plate, the rotating plate is rotated in one direction by a driving device, so that the rotating shaft rotates with respect to the fixed position of the fixed shaft and the hole. Slides in the groove and moves relatively, and the diameter of the circular arrangement of the movable plates changes.

That is, each movable plate pivotally moves at the movable shaft end around the fixed shaft, and the size of the circular shape formed by the inner surface of the bow of each movable plate changes, resulting in the same circular area. To change the flow path area of the orifice plate, and by adjusting the size of the opening of the orifice plate, it is possible to adjust the differential pressure between the upstream side and the downstream side. A suitable movable orifice that can be obtained has been obtained.

[Brief description of the drawings]

FIG. 1 shows a movable orifice according to one embodiment of the present invention, in which a pressure drop change following movable orifice is shown. FIG.

2A and 2B show main members constituting the orifice of FIG. 1, wherein FIG. 2A is a movable plate, FIG. 2B is a holding plate, FIG. 2C is a rotary plate, and FIG. .

3A and 3B schematically show a conventional movable orifice, wherein FIG. 3A is a front view and FIG. 3B is a side view.

FIG. 4 is an explanatory view showing a supply system of spray water to a superheat reducer inside a boiler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Orifice plate 2 Movable plate 2a Fixed shaft 2b Rotating shaft 3 Holding plate 3a Hole 3b Outer ring 3c Inner ring 4 Rotating plate 4a Groove 4b Outer ring 4c Inner ring 4d Driving rod 5 Driving device 6 Orifice plate 7 Valve rod 8 Driving device 9 Overheating 10 water supply pipe 11 movable orifice

Claims (1)

[Claims] 1. A plurality of movable plates each having a fixed shaft protruding at one end of one surface of a bow-shaped curved plate and a movable shaft protruding at the other end of the other surface, an outer ring and an inner ring. Providing a holding plate and a rotating plate each constituted by a circular plate having
A plurality of holes for fitting the fixed shaft on one of the holding plate and the rotating plate are provided on a circumferential locus, and a plurality of radial grooves for sliding and guiding the rotating shaft are provided on the other, and the holding plate and The fixed shaft and the movable shaft are fitted in the holes and the grooves between the rotating plates, and a plurality of movable plates are arranged in a circular shape to form an orifice plate. The orifice plate is connected to a driving device that reciprocates the rotating plate. A movable orifice that follows a pressure loss change.