A pneumatic flushing filter device for the shaft seal water of the main pump in a nuclear power plant

Abstract

The present invention belongs to a flushing filter device, and particularly relates to a pneumatic flushing filter device for the shaft seal water of the main pump in a nuclear power plant. It includes a main pipeline, and the main pipeline is connected to a pipeline through a backflow valve. The lower side end of the pipeline is connected to a sewage discharge pipeline, and the upper side end of the pipeline is connected to a backwashing pipeline. The beneficial effects are as follows: During normal operation, the demineralized water flows upward from the bottom through the pipeline, pushing the backflow valve to close the sewage discharge pipeline, and then passing through the filter upward. When the filter is blocked, the filter is pushed upward by water, driving the connecting rod to open the air valve. The gas pushes the ejector rod to rotate the ball valve and then open the backwashing water pipe. After the backwashing water flows into the pipeline to fill the pipeline with water, the backflow valve rebounds to open the sewage discharge pipeline, and the water above is discharged through the sewage discharge pipe. After the filter is unblocked, the backflow valve is pushed open, the sewage discharge valve is closed, the filter returns to its original position, and the ball valve is pulled back to its original position by the spring. It adopts a passive structure and is automatically triggered, greatly reducing the labor cost.

Description

Technical Field

[0001] The invention belongs to a filter screen flushing device, and in particular relates to a pneumatic filter screen flushing device for shaft seal water of a main pump of a nuclear power plant. Background Art

[0002] The reactor coolant pump is one of the key equipment in a nuclear power plant and is the heart of the nuclear power plant. It forces the coolant in the primary circuit to circulate, thereby transferring the heat energy generated in the reactor to the steam generator to generate steam and drive the steam turbine to do work. If the reactor coolant pump is frequently shut down, it will cause huge economic losses to the power plant.

[0003] The shaft seal is an important component of the reactor coolant pump and the key to the normal operation of the main pump. It is a device to control the leakage of the reactor coolant along the main pump shaft. It is composed of three-stage seal main parts arranged in series, NO.1, NO.2, and NO.3. The life of the shaft seal determines the maintenance cycle of the main pump. Among them, the third-stage shaft seal is injected with sealing water to lubricate the shaft seal surface and prevent boron precipitation. The sealing water injected into the third-stage shaft seal comes from the shaft seal riser. To ensure the normal operation of the third-stage shaft seal, the shaft seal riser must be unobstructed and have a stable water supply. A nuclear power plant has recently experienced multiple cases of filter screens being blocked by microbial corrosion products, resulting in insufficient water supply, which affects the normal operation of the unit. Although the shaft seal water is all desalted water, because there is a balance pipe on the riser connected to the atmosphere to balance the air pressure in the riser, the inside of the riser is directly connected to the atmosphere, which will cause a large amount of air to dissolve in the water, and the bacteria and oxygen content in the water will continue to rise, which is very easy to breed iron bacteria in the riser. Iron bacteria can convert ferrous ions into ferric ions, generating a large amount of water-insoluble corrosion products. After passing through the pipeline, they gather at the flow orifice plate, causing pipeline blockage and thus affecting the normal operation of the main pump.

[0004] Therefore, in order to solve the problem of filter blockage during normal operation of the unit, it is urgent to invent a pneumatic filter flushing device to ensure the normal operation of the pipeline during normal operation of the unit. Summary of the invention

[0005] The object of the present invention is to provide a pneumatic flushing filter screen device for shaft seal water of a main pump of a nuclear power plant, which can solve the problem of filter screen being blocked by corrosion products through structural optimization.

[0006] The technical solution of the present invention is as follows: a pneumatic flushing filter device for the shaft seal water of the main pump of a nuclear power plant, comprising a main pipeline, wherein the main pipeline is connected to the pipeline through a countercurrent valve, the lower side end of the pipeline is connected to the sewage pipeline, and the upper side end of the pipeline is connected to the backwashing pipeline.

[0007] An air source pipeline is also provided below the connection between the pipeline and the backwash pipeline. The air source pipeline is a T-shaped structure with three ends, one end of which is connected to the pipeline and the side of the other end is connected to the open end of the U-shaped pipe.

[0008] The reverse flow valve is connected to the pipeline and the main pipeline respectively through threads. The interior of the reverse flow valve includes a spring, a positioning support, a pipe sleeve and a movable baffle rod. One end of the positioning support is sleeved on the outside of the pipeline through a threaded structure, and one end of the pipe sleeve is sleeved on the outside of the main pipeline through a threaded structure. The positioning support is sleeved on the outside of the pipe sleeve through a threaded structure. A movable baffle rod is provided between the positioning support and the pipe sleeve. The middle of the movable baffle rod is a shaped baffle plate, and the two ends of the baffle plate are round rod structures respectively. The upper and lower rod parts of the movable baffle rod pass through the positioning support and the pipe sleeve respectively, and a spring is sleeved on the upper round rod. The baffle plate and spring of the movable baffle rod are both located between the positioning support and the pipe sleeve.

[0009] The end of the round rod of the movable baffle rod passing through the positioning support is also connected with a connecting rod, the connecting rod goes deep into the sewage pipe, the connecting rod is connected with a sewage outlet baffle, and the end of the sewage pipe is provided with a sewage outlet.

[0010] An intermediate filter is provided in the middle position of the pipeline, and the intermediate filter covers the port of the gas source pipeline. The gas source pipeline goes deep into the pipeline. A column is provided inside the part of the gas source pipeline located in the pipeline. A spring is arranged on the outer sleeve of the column. The column is connected to a connecting rod, and the connecting rod is connected to a fan-shaped baffle.

[0011] A partition plate is arranged in the gas source pipeline, a gas source hole is opened on the partition plate, the gas source hole is connected with the gas pipe, and a fan-shaped baffle covers the gas source hole.

[0012] An I-shaped cylindrical rod is arranged inside one end of the U-shaped tube, and an exhaust port is opened on the side of the end.

[0013] A ball valve is arranged in the backwash pipeline, and a filter is arranged outside the ball valve in the backwash pipeline.

[0014] A ball valve stem is arranged at a position corresponding to the ball valve on the outer side of the backwashing pipeline.

[0015] The stem portion of the ball valve stem is connected to one end of a spring, and the other end of the spring is connected to the outer wall surface of the backwashing pipeline.

[0016] The beneficial effects of the present invention are as follows: during normal operation, desalted water flows upward from the bottom through the pipeline, pushes the backflow valve and the back discharge pipeline to close, and then passes through the filter upward. When the filter is blocked, the filter is pressed upward by the water, driving the connecting rod to open the valve, and the gas pushes the push rod to rotate the ball valve and then open the backwash water pipe. After the backwash water flows into the pipeline to fill the pipe with water, the backflow valve rebounds to open the sewage pipe, and the water above will flush the filter and be discharged through the sewage pipe. After the filter is unblocked, the backflow valve is pushed open, the sewage valve is closed, the filter returns to its original position, the valve is closed, and the ball valve is pulled back to its original position by the spring, so that the waterway operates normally. The gas source adopts a passive structure and is automatically triggered, which greatly reduces labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an overall schematic diagram of a pneumatic flushing filter device for shaft seal water of a nuclear power plant main pump provided by the present invention;

[0018] Figure 2 This is a schematic diagram of the back of a pneumatic flushing filter device for shaft seal water of a nuclear power plant main pump provided by the present invention;

[0019] Figure 3 This is the cross-sectional view of the main pipeline;

[0020] Figure 4 It is a cross-sectional view of the U-tube and gas source pipeline.

[0021] In the figure: 1 backwash pipe, 2 sewage pipe, 3 backflow valve, 4 main pipe, 5 ball valve stem, 6 spring, 7 air source pipe, 8 U-type pipe, 9 ball valve, 10 filter, 11 fan-shaped baffle, 12 connecting rod, 13 column, 14 spring, 15 middle filter, 16 connecting rod, 17 sewage outlet baffle, 18 sewage outlet, 19 positioning support, 20 spring, 21 movable baffle, 23 air pipe, 24 air source hole, 25 I-shaped cylindrical rod, 26 exhaust port, 27 pipe, 28 pipe sleeve, 29 partition plate. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] The pneumatic flushing filter device for shaft seal water of the main pump of a nuclear power plant provided by the present invention is mainly divided into two parts, one is the linkage mechanism between the backflow valve 3 and the drain valve port 2, and the other is the linkage mechanism between the filter 15 and the air source 7.

[0024] like Figure 1 As shown, a pneumatic flushing filter device for the shaft seal water of the main pump of a nuclear power plant includes a main pipeline 4, which is connected to a pipeline 27 through a reverse flow valve 3, the lower side end of the pipeline 27 is connected to a sewage pipeline 2, and the upper side end of the pipeline 27 is connected to a backwashing pipeline 1.

[0025] like Figure 2 and 4 As shown, an air source pipeline 7 is also connected below the connection between the pipeline 27 and the backwash pipeline 1. The air source pipeline 7 is a T-shaped structure with three ends, one end of which is connected to the pipeline 27, and the side of one end is connected to the open end of the U-shaped tube 8.

[0026] like Figure 3 As shown, the reverse flow valve 3 is connected to the pipeline 27 and the main pipeline 4 through threads, and the interior of the reverse flow valve 3 includes a spring 20, a positioning support 19 and a movable stopper 21. One end of the positioning support 19 is sleeved on the outside of the pipeline 27 through a threaded structure, and one end of the pipe sleeve 28 is sleeved on the outside of the main pipeline 4 through a threaded structure. The positioning support 19 is sleeved on the outside of the pipe sleeve 28 through a threaded structure. A movable stopper 21 is installed between the positioning support 19 and the pipe sleeve 28. The middle of the movable stopper 21 is a disc-shaped stopper, and the two ends of the stopper are round rod structures. The upper and lower rod parts of the movable stopper 21 pass through the positioning support 19 and the pipe sleeve 28 respectively. The spring 20 is sleeved on the upper round rod, and the stopper of the movable stopper 21 and 20 are both located between the positioning support 19 and the pipe sleeve 28. The end of the round rod of the movable baffle 21 passing through the positioning support 19 is also connected to one end of the connecting rod 16. The connecting rod 16 penetrates into the sewage pipe 2. The other end of the connecting rod 16 is connected to the sewage outlet baffle 17. The end of the sewage pipe 2 is provided with a sewage outlet 18; an intermediate filter screen 15 is provided in the middle position of the pipe 27. The intermediate filter screen 15 covers the port of the air source pipe 7. The part of the air source pipe 7 that penetrates into the pipe 27 is an L-shaped structure. The part of the air source pipe 7 located in the pipe 27 is provided with a column 13. The column 13 is provided with a spring 14 on the outside. The column 13 is connected to the connecting rod 12, and the connecting rod 12 is connected to the fan-shaped baffle 11, such as Figure 4 As shown, a partition plate 29 is provided in the air source pipeline 7, and an air source hole 24 is opened on the partition plate 29, and the air source hole 24 is connected to the air pipe 23. The fan-shaped baffle 11 covers the air source hole 24. An I-shaped cylindrical rod 25 is provided inside one end of the U-shaped tube 8, and an exhaust port 26 is opened on the side of the end. Figure 3 As shown, a ball valve 9 is arranged in the backwash pipe 1, a filter screen 10 is arranged on the outside of the ball valve 9 in the backwash pipe 1, a ball valve stem 5 is arranged on the outside of the backwash pipe 1 at a position corresponding to the ball valve 9, the rod part of the ball valve stem 5 is connected to one end of a spring 6, and the other end of the spring 6 is connected to the outer wall surface of the backwash pipe 1.

[0027] The working process of the present invention is as follows:

[0028] Water flows upward from the bottom of the main pipe 4, first passes through the backflow valve 3, and the backflow valve 3 is connected to the pipes on both sides by threads. The internal structure includes a spring 20, a positioning support 19 and a movable baffle 21. The movable baffle 21 is pressed upward due to the water pressure. At this time, the sewage outlet baffle 17 connected to the top of the movable baffle 21 through the connecting rod 16 is pressed down, and the sewage outlet 18 is closed. The water passes through the upper filter 15 and enters the main pump. When the filter is blocked due to too many filtered impurities, the pressure on both sides of the filter is unbalanced, and the filter is pressed upward. The column 13 above the filter drives the fan-shaped baffle 11 to rotate via the connecting rod 12. At this time, the air source hole 24 is connected to the air pipe 23. The air source is provided by the air storage tank. The pipe is connected to the fan-shaped baffle, and the gas enters the U-shaped pipe 8 through the gas source hole. A cylindrical rod 25 is installed on one side of the U-shaped pipe. The gas pushes the cylindrical rod 25 forward, pushing the ball valve stem 5 to rotate, so that the ball valve 9 is passed, and then the water in the backwash pipe 1 is flushed into the pipe. At this time, the pipe is full of water, and the backflow valve 3 rebounds, driving the sewage outlet baffle 17 to lift up. The water above backwashes the filter screen 15 and flows out of the sewage outlet 18 with impurities. At this time, the filter screen 15 rebounds, the gas source hole is closed, and the ball valve stem 5 is pulled back by the spring 6 connected to the pipe wall, driving the cylindrical rod in the U-shaped pipe 8 to move downward. Since there is a small gap between the lower end cylindrical rod and the pipe wall, the internal gas can be discharged from the exhaust port 26 of the U-shaped pipe through the gap. At the same time, the backflow valve is pressed up, the sewage outlet is closed, and water enters the main pump through the filter screen.

[0029] During the operation of the unit, desalted water pushes the reverse flow valve 3 upward from the bottom of the main pipeline 4 to filter through the filter 15 to the main pump. When the filter filters too many impurities and causes blockage, the water at the bottom presses the filter up due to pressure. At this time, the column 13 above the filter drives the connecting rod 12 to push the fan-shaped baffle 11, and the air source port 24 is connected to the air pipe 23. The gas pushes the I-shaped cylindrical rod 25 to move upward, thereby pushing the ball valve stem 5 to rotate, the ball valve 9 opens, and backwash water enters the pipeline. The rebound of the reverse flow valve drives the sewage outlet 17 to open, and water flows out of the sewage outlet with impurities through the flushing filter. At the same time, the filter returns to its original position, the air source hole is closed, and the spring drives the ball valve stem to return to its position. The backwash pipeline is closed, the reverse flow valve is pressed up by the water below, and the sewage outlet is closed. At this time, the waterway operates normally, which can ensure the normal operation of the unit within the overhaul period.

Claims

1. A pneumatic flushing filter device for the shaft seal water of the main pump in a nuclear power plant, characterized in that: It includes a main pipeline, and the main pipeline is connected to a pipeline through a backflow valve. A sewage discharge pipeline is connected to the side end of the lower part of the pipeline, and a backwashing pipeline is connected to the side end of the upper part of the pipeline; Below the connection of the pipeline and the backwashing pipeline, there is also a gas source pipeline. The gas source pipeline has a T-shaped structure with three ends. One end is connected to the pipeline, and the side of one end is connected to the open end of a U-shaped pipe; The backflow valve is respectively connected to the pipeline and the main pipeline through threads. The inside of the backflow valve includes a spring, a positioning support, a bushing and a moving stop rod. One end of the positioning support is sleeved outside the pipeline through a threaded structure, and one end of the bushing is sleeved outside the main pipeline through a threaded structure. The positioning support is sleeved outside the bushing through a threaded structure. There is a moving stop rod between the positioning support and the bushing. The middle of the moving stop rod is a shaped baffle, and both ends of the baffle are round rod structures. The upper and lower rod parts of the moving stop rod pass through the positioning support and the bushing respectively. A spring is sleeved on the upper round rod, and both the baffle of the moving stop rod and the spring are located between the positioning support and the bushing; The end of the round rod of the moving stop rod passing through the positioning support is also connected to a connecting rod. The connecting rod extends into the sewage discharge pipeline. The connecting rod is connected to a sewage discharge port baffle, and a sewage discharge port is arranged at the end of the sewage discharge pipeline; In the middle position of the pipeline, there is an intermediate filter screen. The intermediate filter screen covers the port of the gas source pipeline. The gas source pipeline extends into the pipeline. There is a column inside the part of the gas source pipeline located in the pipeline. A spring is sleeved outside the column. The column is connected to the connecting rod, and the connecting rod is connected to a sector baffle; A partition plate is arranged in the gas source pipeline. A gas source hole is opened on the partition plate. The gas source hole is communicated with an air pipe, and the sector baffle covers the gas source hole.

2. A pneumatic flushing filter device for the shaft seal water of the main pump in a nuclear power plant according to claim 1, characterized in that: An I-shaped cylindrical rod is arranged inside one end of the U-shaped pipe, and an exhaust port is opened on the side of the end; 3. A pneumatic flushing filter device for the shaft seal water of the main pump in a nuclear power plant according to claim 1, characterized in that: A ball valve is arranged in the backwashing pipeline, and a filter screen is arranged outside the ball valve in the backwashing pipeline; 4. A pneumatic flushing filter device for the shaft seal water of the main pump in a nuclear power plant according to claim 1, characterized in that: A ball valve stem is arranged at the position corresponding to the ball valve on the outside of the backwashing pipeline; 5. A pneumatic flushing filter device for the shaft seal water of the main pump in a nuclear power plant according to claim 4, characterized in that: One end of a spring is connected to the rod part of the ball valve stem, and the other end of the spring is connected to the outer wall surface of the backwashing pipeline.

Images