WO2024007525A1

WO2024007525A1 - Front water inlet pre-intercepting and filtering device for pump station of nuclear power plant

Info

Publication number: WO2024007525A1
Application number: PCT/CN2022/137178
Authority: WO
Inventors: 刘生根; 郭树生; 张伟; 李剑波; 张富美; 彭浩; 杨墨铭
Original assignee: 中广核研究院有限公司; 中国广核集团有限公司; 中国广核电力股份有限公司
Priority date: 2022-07-04
Filing date: 2022-12-07
Publication date: 2024-01-11
Also published as: CN115317996B; CN115317996A

Abstract

A front water inlet pre-intercepting and filtering device for a pump station of a nuclear power plant, comprising: a frame (10), annular chains (20) being respectively provided on two sides of the frame (10), and the bottom ends of the annular chains (20) being spaced apart from the bottom of a water flow channel; mesh plates (30) continuously and fully distributed on the two annular chains (20), and the two sides of each mesh plate (30) being fixedly connected the two annular chains (20), respectively; and a driving device comprising a motor (110), a main shaft (116) mounted on the frame (10) by means of bearing seats (114), and two chainwheels (118) provided on the main shaft (116), the motor (110) driving the main shaft (116) to rotate, and driving, by means of the engagement of the two chainwheels (118) and the two annular chains (20), the two annular chains (20) and the mesh plates (30) fixedly connected to the two annular chains (20) to perform reciprocating motion. In the front water inlet pre-intercepting and filtering device for a pump station of a nuclear power plant, the bottom ends of the annular chains (20) and the bottom ends of the mesh plates (30) are all spaced apart from the bottom of the water flow channel, thereby guaranteeing a safe water passing channel under an extreme working condition that all meshes (302) are blocked, performing non-full-section water passing pre-interception, increasing the flow passing section, effectively pre-intercepting and filtering marine organisms, and guaranteeing safe and stable operation of the unit.

Description

Pre-interception and filtering device for water inflow at the front of nuclear power plant pumping station

Technical field

The invention belongs to the technical field of interception and pollution cleaning in Binhai nuclear power plants. More specifically, the invention relates to a pre-interception and filtering device for water inflow from the front of a nuclear power plant pumping station.

Background technique

Nuclear power plants at home and abroad are generally located in coastal locations, using seawater as the final heat sink for the nuclear power plant. In order to ensure the safe operation of nuclear power plants, it is usually necessary to intercept and filter seawater. At present, nuclear power plant pumping stations generally intercept, filter and clean seawater through three barriers: the first barrier is an interception net in front of the water intake, the second barrier is a coarse grille and a fine grille (including a cleaning machine), and the third barrier The third channel is a rotating filter (mainly a side water inlet plate and frame rotating filter or a drum filter). The mesh openings of the three barriers decrease in sequence to achieve step-by-step interception and filtration of seawater to meet the requirements of the cold source of the nuclear power plant.

In recent years, the successive incidents of blockage of water inlets of nuclear power plants have revealed that the seawater filtration and cleaning facilities of nuclear power plants are still insufficient. How to strengthen the pre-interception and filtration function in front of the filtration terminal has attracted more and more attention from researchers, such as , one of the important directions of current research is to replace the fine grid cleaning machine with low interception and cleaning efficiency upstream of the drum filter with a pre-interception plate and frame rotating filter.

The plate and frame rotary filter can be divided into side water inlet and front water inlet according to the water inlet mode: the side water inlet plate and frame filter requires a complex civil infrastructure structure, and the water intake pumping station of the nuclear power plant is compactly arranged, and the flow direction of the flow channel is It has solidified, so we can only consider adding a front water inlet frame filter. The front water inlet plate and frame filter in the related technology generally has problems such as small flow cross section, easy entrainment of dirt, which affects the safety of water intake, easy fall of dirt during the lifting process of the sewage bucket, and incomplete backwashing, which causes dirt entrainment, which limits the its application in the field of nuclear power.

Contents of the invention

The object of the present invention is to overcome at least one defect in the prior art and provide a front water inlet pre-interception filtering device of a nuclear power plant pumping station to effectively pre-filter and clean marine organisms and ensure the safe and stable operation of the unit.

In order to achieve the above-mentioned object of the invention, the present invention provides a front water inlet pre-interception filtering device of a nuclear power plant pumping station, which includes:

A frame, annular chains are provided on both sides of the frame, and the bottom end of the annular chain is spaced apart from the bottom of the water channel flow channel;

The mesh plate is continuously covered on the two annular chains, and both sides of the mesh plate are respectively fixedly connected to the two annular chains; and

The driving device includes a motor, a main shaft installed on the frame through a bearing seat, and two sprockets arranged on the main shaft. The motor drives the main shaft to rotate, and the main shaft is driven by the two sprockets. The meshing of the sprocket and the two annular chains drives the two annular chains and the mesh plate fixedly connected to the two annular chains to reciprocate.

According to one embodiment of the water inlet pre-interception filtering device at the front of a nuclear power plant pumping station of the present invention, an upper frame is provided on the top of the frame, and the upper frame includes a base, a top beam opposite to the base, and a A column is provided between the base and the top beam, and the driving device is arranged in the accommodation space jointly formed by the base, the top beam and the column.

According to one embodiment of the water inlet pre-interception filtering device at the front of the nuclear power plant pumping station of the present invention, a cover is provided around the receiving space, and an observation window is provided on the cover.

According to one embodiment of the front water inlet pre-interception filtering device of a nuclear power plant pumping station of the present invention, the upper frame is provided with a backwash system and a sewage drain tank. The backwash system includes a flushing water pipe and multiple water pipes arranged on the flushing water pipe. When the screen plate moves downward from the upper frame, the nozzle tilts downward to flush the screen plate, and the washed dirt is discharged through the sewage drain channel.

According to one embodiment of the water inlet pre-interception filtering device at the front of a nuclear power plant pumping station of the present invention, the motor drives the main shaft to rotate through a reducer, and the reducer is equipped with a torque arm on the descending side of the mesh plate. The support provided by the arm is fixed on the ground, and the support is equipped with a safety pin and a cylindrical pin. When the safety pin is overloaded, it is shortened to cause the displacement of the cylindrical pin, triggering the electrical proximity switch to send out an alarm signal and causing the motor to Stop turning.

According to one embodiment of the front water inlet pre-interception filtering device of a nuclear power plant pumping station of the present invention, the mesh plate is provided with a mesh frame and mesh pieces installed on the mesh frame, and both sides of the mesh frame are fixed respectively. on said chain.

According to one embodiment of the water inlet pre-interception filtering device at the front of the nuclear power plant pumping station of the present invention, the mesh plate frame is provided with a sewage bucket at an angle of 10-45° with the horizontal direction.

According to one embodiment of the water inlet pre-interception filtering device at the front of a nuclear power plant pumping station of the present invention, the frame is provided with a mesh support and guide mechanism, the mesh frame is provided with guide wheels, and the guide wheels are arranged along the The mesh plate supports the walking of the guide mechanism.

According to one embodiment of the water inlet pre-interception filtering device at the front of a nuclear power plant pumping station of the present invention, the bearing seat is provided with an adjusting rod, and the adjusting rod is provided with a locking nut, which can be adjusted by tightening or loosening the locking nut. The position of the spindle and the tightness of the endless chain.

According to one embodiment of the water inlet pre-interception filtering device at the front of a nuclear power plant pumping station of the present invention, the frame is arranged in sections in its height direction, and the structures of adjacent sections are adapted and can be disassembled and assembled.

According to one embodiment of the water inlet pre-interception filtering device at the front of a nuclear power plant pumping station of the present invention, the reserved height of the flow channel between the bottom end of the annular chain and the bottom of the water channel flow channel is determined in the following manner:

S1. Divide the cross-section of the water passage into section 1, section 0 and section 2 in the flow direction. Section 1 is the section upstream of the mesh plate, section 0 is the section at the mesh plate, and section 2 is the section downstream of the mesh plate;

S2. Establish an equation, in which the flow rate flowing through section 0 is the total flow rate of the flow channel:

Q＝Q ₁ +Q ₂ ＝v ₁ A ₁ +v ₀ A ₂ (1)

In formula (1), Q ₁ is the flow rate flowing through the pre-interception filter device, Q ₂ is the flow rate flowing through the bottom flow channel, v ₁ is the flow rate of the pre-interception filter device, v ₀ is the flow rate of the bottom flow channel, A ₁ is the net flow area of the pre-interception filter device, and A ₂ is the flow area of the bottom flow channel;

A ₂ =Bh (2)

In formula (2), B is the width of the flow channel, h is the reserved height of the bottom flow channel,

Assuming that the pre-interception filter device is completely blocked, the total head loss (h _L1-2 ) is expressed by the head loss of the bottom flow channel:

h _L1-2 =Δh ₂ (3)

In formula (4), ξ ₁ is the resistance coefficient when the cross section suddenly shrinks, ξ ₂ = 0.5 (1-h/H ₁ ); ξ ₃ is the resistance coefficient when the cross section suddenly expands, ξ ₃ = (1-h/H ₂ ) ² ;

S3. Determine the channel flow rate Q, channel width B, and channel height H1 according to the actual factory site conditions. According to h _L1-2 ≤ 250mm, combine equations (1)-(4) to obtain the reserved height h of the bottom channel. Minimum value required.

Compared with the prior art, in the front water inlet pre-interception filtering device of the nuclear power plant pumping station of the present invention, the bottom end of the annular chain is spaced from the bottom of the water channel flow channel, and the mesh plate fixedly connected to the two annular chains is also connected to the water channel. The bottoms of the flow channels are spaced apart, so even if the entire mesh is blocked, there is still a safe water passage, which can realize pre-interception of non-full-section frontal water inflow and increase the flow cross-section, ensuring the circulating water system and nuclear safety of the nuclear power plant. Under the premise of reducing the water intake of the important plant water system, it is possible to effectively pre-intercept, filter and clean the small-sized marine organisms that invade the nuclear power plant pumping station, ensuring the safe and stable operation of the unit.

Description of the drawings

The following is a detailed description of the front water inlet pre-interception filtration device of the nuclear power plant pumping station of the present invention and its technical effects with reference to the accompanying drawings and specific embodiments, wherein:

Figure 1 is a schematic structural diagram of the front water inlet pre-interception filtering device of the nuclear power plant pumping station according to the present invention.

Figure 2 is a schematic structural diagram of the upper frame of the front water inlet pre-interception filtering device of the nuclear power plant pumping station according to the present invention.

Figure 3 is a schematic structural diagram of the backwash system in the front water inlet pre-interception filtering device of the nuclear power plant pump station according to the present invention.

Figure 4 is a schematic structural diagram of the driving device in the front water inlet pre-interception filtering device of the nuclear power plant pumping station according to the present invention.

Figure 5 is a schematic structural diagram of the overload protection device in the front water inlet pre-interception filtering device of the nuclear power plant pumping station according to the present invention.

Figure 6 is a schematic structural diagram of the mesh plate in the front water inlet pre-interception filtering device of the nuclear power plant pumping station according to the present invention.

Figure 7 is a schematic structural diagram of a sewage bucket in the front water inlet pre-interception filtering device of the nuclear power plant pumping station according to the present invention.

Figure 8 is a schematic diagram of the segmented arrangement of the frame in the front water inlet pre-interception filtering device of the nuclear power plant pump station according to the present invention.

Figure 9 is an enlarged schematic diagram of the installation guide rails, civil construction foundation guide rails and working chain walking guide rails in the front water inlet pre-interception filtering device of the nuclear power plant pumping station according to the present invention.

Figure 10 is a schematic diagram of the hydraulic model at the screen plate in the front water inlet pre-interception filtering device of the nuclear power plant pump station according to the present invention.

in:

10--frame; 100--base; 102--top beam; 104--column; 106--cover; 108--observation window; 110--motor; 112--reducer; 114--bearing seat; 116--Spindle; 118--Sprocket; 120--Backwash water pipe; 122--Nozzle; 124--Sewage trough; 126--Safety pin and cylindrical pin; 128--Adjusting rod; 130--Lock nut ; 132--mesh plate support and guide mechanism; 134--working chain walking guide rail; 136--installation guide rail; 138--civil construction foundation guide rail; 20--annular chain; 200--chain plate; 202--roller; 204- -Roller shaft; 30--screen plate; 300--screen frame; 302--mesh; 304--sewage bucket; 306--guide wheel; 308--arc type mechanical self-sealing structure.

Detailed ways

In order to make the purpose, technical solution and technical effect of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation modes. It should be understood that the specific embodiments described in this specification are only for explaining the present invention and are not intended to limit the present invention.

Referring to Figures 1 to 9, the present invention provides a front water inlet pre-interception filtering device of a nuclear power plant pumping station, which includes:

Frame 10, annular chains 20 are respectively provided on both sides of the frame 10, and the bottom end of the annular chain 20 is spaced apart from the bottom of the water channel flow channel;

The mesh plate 30 is continuously covered on the two annular chains 20, and both sides of the mesh plate 30 are respectively fixedly connected to the two annular chains 20; and

The driving device includes a motor 110, a main shaft 116 installed on the frame 10 through a bearing seat 114, and two sprockets 118 provided on the main shaft 116. The motor 110 is started to drive the main shaft 116 to rotate, and the main shaft 116 is rotated through the two sprockets 118. The meshing with the two annular chains 20 drives the two annular chains 20 and the mesh plate 30 fixedly connected to the two annular chains 20 to reciprocate.

The integrated frame 10 with its own flow channel used in the front water inlet pre-interception filtering device of the nuclear power plant pumping station of the present invention creatively integrates the non-full-section interception bottom flow channel into the device, and the device is arranged as a whole in the water channel flow channel. On the one hand, it solves the problem of It overcomes the stringent requirements of non-full-section interception and filtration devices on civil infrastructure. On the other hand, it avoids the risk of the device being suspended in the water inlet channel and prone to collapse under earthquake conditions, resulting in blockage of the inlet water channel, thus ensuring the nuclear safety of nuclear power plants. Water is safe.

Referring to Figure 2, an upper frame is provided on the top of the frame 10. The upper frame includes a base 100, a top beam 102 opposite to the base 100, and a column 104 located between the base 100 and the top beam 102. The driving device is provided In the accommodation space enclosed by the base 100 , the top beam 102 and the columns 104 , the base 100 , the top beam 102 and the columns 104 are all structural parts formed by pressing and welding carbon steel plates. A cover 106 is provided around the storage space, and an observation window 108 is provided on the cover 106. Workers can observe the dirt on the surface of the mesh 302 from the outside through the observation window 108 without being exposed to the risk of splashing. The cover 106 adopts a fully enclosed structure, which can prevent flushing water from splashing and effectively protect workers from contact with mechanical rotating parts to ensure personal safety. According to one embodiment of the present invention, the cover 106 is connected by a flange, which is easy to install and can form a flow guide with the base 100. The flushing water splashed onto the cover 106 flows back directly, ensuring that no water overflows.

Please refer to Figures 2 and 3 together. The upper frame is provided with a backwashing system and a sewage tank 124. The backwashing system includes a flushing water pipe 120 and a plurality of nozzles 122 provided on the flushing water pipe 120. It is implemented as shown in Figure 3 In this method, the flushing water pipe 120 is provided with two rows of nozzles 122 up and down, and both rows of nozzles 122 are arranged at an angle. After the dirt collected by the sewage bucket 304 is lifted to the backwash position, flushing water with a certain pressure is sprayed out through the nozzle 122 on the flushing water pipe 120 (the flushing water supply is provided by a special flushing water system) to flush the debris down to the sewage discharge station. 124 in the groove, and then discharged into the sewage ditch to keep the screen 30 clean. The sewage drain 124 is arranged at a reasonable position on the upper frame to ensure that all sewage is discharged. When the screen plate 30 moves downward from the upper frame, the nozzle 122 tilts downward to flush the screen plate 30 , and the flushed dirt is discharged through the drain groove 124 . Different from traditional equipment where the backwash water pipe is arranged on the lifting side of the screen plate 30, the present invention adopts a full-turning waste discharge design and arranges the backwash water pipe on the descending side of the screen plate 30. Large-sized dirt falls into the sewage drain tank 124 by its own weight, and small-sized dirt falls into the sewage tank 124 by its own weight. Large-scale dirt is flushed to the sewage tank 124 by means of backwash water, which solves the problem of dirt entrainment in the screen plate 30 of traditional equipment due to incomplete backwash.

Please refer to Figures 2 and 4. The bearing seat 114 is fixed on the upper frame through a screw nut. The bearing seat 114 is provided with an adjusting rod 128. The adjusting rod 128 is provided with a locking nut 130. By tightening or screwing Loosen the locking nut 130, and the two bearing seats 114 can move along the slideway to adjust the height and level of the main shaft 116 and the tightness of the annular chain 20.

Referring to FIG. 5 , the driving device includes a motor 110 , a hard-tooth surface reducer 112 , a support (not shown), and a mechanical overload device. The reducer 112 is installed at one end of the main shaft 116. When working, the motor 110 first converts electrical energy into mechanical energy, and transmits a certain power and rotation speed to the main shaft 116 through the reducer 112, driving the main shaft 116 and the sprocket 118 to rotate, thereby driving the chain hanging on the chain. The annular chain 20 and the mesh plate 30 on the wheel 118 move up and down in a reciprocating cycle.

The overload protection device includes electrical protection and mechanical protection. Among them, the reducer 112 is equipped with a torque arm on the descending side of the mesh plate 30. The support seat of the torque arm is fixed on the primary embedded part on the ground. A safety pin and a cylinder are installed on the support. Pin 126, when the equipment is overloaded, the safety pin is shortened to cause the cylindrical pin 126 to shift, thereby triggering the electrical proximity switch. The electrical proximity switch sends an alarm signal, and the motor 110 stops rotating and provides mechanical overload protection. Electrical protection can use over-current and low-voltage protection devices to effectively protect motors and equipment.

Referring to FIG. 6 , the screen panel 30 is provided with a screen frame 300 and a screen piece 302 installed on the screen frame 300 . Both sides of the screen frame 300 are respectively fixed on the annular chain 20 . The mesh 302 is made of stainless steel punched mesh and is fixed on the mesh frame 300 with bolts. The seal between the mesh plates adopts an arc-type mechanical self-sealing structure 308. The mesh 302 is fixed on the outer surface of the mesh frame 300, and an independent connection system is used to facilitate observation and replacement of the mesh 302. Both ends of the screen frame 300 are fastened to the chains 20 through long bolts. The two annular chains 20 are respectively hung on the sprockets 118 of the main shaft 116. As the sprocket 118 rotates, the roller 202 engages with the sprocket 118 to drive the screen 30 It circulates up and down with the annular chain 20 .

The endless chain 20 includes a chain plate 200, a roller 202 and a roller shaft 204. The material of the roller 202 is MC nylon, which can improve the wear resistance of its engagement with the sprocket 118. The backwash water pipe 120 of traditional equipment is arranged on the lifting side of the screen plate 30. In order to facilitate the backwashing of dirt, the dirt bailing bucket is generally arranged horizontally, which can easily cause the dirt in the dirt bailing bucket to fall into the flow channel in advance during the lifting of the screen plate 30. . Please refer to Figure 7 as well. The screen frame 300 is arranged at a certain angle with the horizontal direction.

The dirt bailing bucket 304 achieves a better "accommodating" effect during the dirt lifting process and solves the problem of early dirt falling. In addition, the screen frame 300 is also equipped with guide wheels 306, and the frame 10 is provided with a screen support and guide mechanism 132. The guide wheels 306 can walk along the screen support and guide mechanism 132 to ensure the smooth operation of the screen 30. On the one hand, the screen support and guide mechanism 132 plays a guiding role for the operation of the screen 30 , and on the other hand, it provides support for the screen 30 when the screen 30 is subjected to the water level pressure difference to prevent the screen 30 from being crushed.

Please refer to Figures 8 and 9. According to an embodiment of the present invention, a pre-interception and filtering device for water inflow at the front of a nuclear power plant pumping station, the frame 10 is arranged in sections in its height direction, and the structures of adjacent sections are adapted and can be disassembled and assembled. , pin shaft positioning and bolt connection are used between each section, and segmented hoisting is achieved with the help of supporting square steel, which solves the problem of insufficient driving hoisting height and hoisting tonnage of the nuclear power plant pumping station. For example, please refer specifically to Figure 8. The frame 10 adopts a segmented design and is composed of three sections. The top section is composed of two straight sections of frame and track, the middle section is composed of three straight sections of frame and track, and the bottom section is composed of one straight section. It is composed of semicircular frame and track. Flange connections are used between each section, the six bottom holes of the bottom frame are connected to the bottom positioning device of the foundation, and the top section is connected to the upper frame base with bolts.

Please refer specifically to Figure 9. The inner wall of the entire frame 10 is provided with a working chain walking guide rail 134, and the outer wall is provided with an installation guide rail 136 used in conjunction with the civil engineering foundation guide rail 138. Such an installation can transmit water pressure and seismic loads from the front and rear of the device. to the civil foundation to ensure that the equipment will not be crushed in the event of extreme pressure differences or earthquakes.

The guide rail design of the frame 10, on the one hand, breaks through the traditional fixed installation method in which the equipment and the civil foundation are connected by embedded bolts, and realizes the portable installation of the equipment. It can be lifted out of the water channel as a whole for daily maintenance of the equipment frame, solving the problem of traditional equipment Maintenance can only be carried out by high-risk operations such as diving; on the other hand, it can provide support for the underground frame of the equipment, conduct the water pressure and seismic load before and after the device to the civil foundation, and ensure the structure of the equipment when it withstands the ultimate water level difference pressure. Safety.

In addition, as shown in Figure 10, the present invention also constructs a hydraulic model of the pre-interception filtration device, and proposes a non-full-section pre-interception filtration method to ensure the important plant water system of the nuclear power plant circulating water system (CRF) and nuclear safety level. (SEC) water intake, assuming that the pre-interception filtering device is completely blocked, establish its hydraulic model to provide a theoretical basis for the design value of the reserved size of the bottom flow channel.

Model overview

The cross-section of the water passage is divided into section "1", section "0" and section "2" in the flow direction.

calculation equation

The flow rate flowing through section "0" is the total flow rate of the flow channel:

Q＝Q ₁ +Q ₂ ＝v ₁ A ₁ +v ₀ A ₂ (1)

In the formula, Q1 is the flow rate flowing through the pre-interception filter device (0 when completely blocked), Q2 is the flow rate flowing through the bottom flow channel, v ₁ is the flow rate of the pre-interception filter device, v ₀ is the flow rate of the bottom flow channel Flow rate, A ₁ is the net flow area of the pre-interception filter device (0 when completely blocked), A ₂ is the flow area of the bottom flow channel:

A ₂ =Bh (2)

In the formula, B is the width of the flow channel, h is the reserved height of the bottom flow channel

According to "resistance balance", at section "0", the head loss (Δh ₁ ) flowing through the pre-interception filter device is equal to the head loss (Δh ₂ ) of the bottom flow channel. Since the pre-interception filter device is assumed to be completely blocked, the total head loss (h _L1-2 ) is expressed by the head loss of the bottom flow channel:

h _L1-2 =Δh ₂ (3)

In the formula, ξ ₁ is the resistance coefficient when the cross section suddenly shrinks, ξ ₂ = 0.5 (1-h/H ₁ ); ξ ₃ is the resistance coefficient when the cross section suddenly expands, ξ ₃ = (1-h/H ₂ ) ² .

According to the actual site conditions, the flow channel flow Q, the flow channel width B, and the flow channel height H1 are all known values. According to the design requirements for head loss in NB/T 25046-2015 "Code for Hydraulic Design of Nuclear Power Plants", h _{L1 -2} ≤250mm, by combining equations (1)-(4), the minimum requirement for h of the bottom flow channel can be obtained.

Based on the above detailed description of the embodiments of the present invention, it can be seen that compared with the prior art, in the front water inlet pre-interception filtering device of the nuclear power plant pumping station of the present invention, the bottom end of the annular chain 20 is spaced from the bottom of the water channel flow channel. The mesh plate 30 fixedly connected to the two annular chains 20 is also spaced from the bottom of the water channel flow channel. Therefore, even if the entire mesh plate 30 is blocked, there is still a safe water passage, which can realize pre-interception of non-full-section front water inflow. , increase the flow end face, and on the premise of ensuring the water intake of the nuclear power plant circulating water system and the important nuclear safety level plant water system, it is possible to effectively pre-intercept, filter and clean the small-sized marine organisms that invade the nuclear power plant pumping station, ensuring Safe and stable operation of the unit.

Based on the above principles, the present invention can also make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

A pre-interception and filtering device for water inflow from the front of a nuclear power plant pumping station, which is characterized by including:

A frame, annular chains are provided on both sides of the frame, and the bottom end of the annular chain is spaced apart from the bottom of the water channel flow channel;

The mesh plate is continuously covered on the two annular chains, and both sides of the mesh plate are respectively fixedly connected to the two annular chains; and

The driving device includes a motor, a main shaft installed on the frame through a bearing seat, and two sprockets arranged on the main shaft. The motor drives the main shaft to rotate, and the main shaft is driven by the two sprockets. The meshing of the sprocket and the two annular chains drives the two annular chains and the mesh plate fixedly connected to the two annular chains to reciprocate.
The front water inlet pre-interception filtering device of a nuclear power plant pumping station according to claim 1, characterized in that an upper frame is provided on the top of the frame, and the upper frame includes a base and a top beam opposite to the base. , and a column located between the base and the top beam, the driving device is arranged in the accommodation space jointly surrounded by the base, the top beam and the column.
The front water inlet pre-interception filtering device of a nuclear power plant pumping station according to claim 2, characterized in that a cover is provided around the receiving space, and an observation window is provided on the cover.
The front water inlet pre-interception filtration device of a nuclear power plant pumping station according to claim 2, characterized in that the upper frame is provided with a backwash system and a sewage drain, and the backwash system includes a flushing water pipe and a flushing water pipe. There are multiple nozzles on the water pipe. When the screen plate moves downward from the upper frame, the nozzles tilt downward to flush the screen plate, and the washed dirt is discharged through the sewage drain channel.
The front water inlet pre-intercept filtering device of a nuclear power plant pumping station according to claim 2, characterized in that the motor drives the main shaft to rotate through a reducer, and the reducer is equipped with a torque arm on the descending side of the screen plate. , the support provided by the torque arm is fixed on the ground, and the support is equipped with a safety pin and a cylindrical pin. When the safety pin is overloaded, it is shortened to cause the displacement of the cylindrical pin, triggering the electrical proximity switch to send out an alarm signal and Stop the motor from rotating.
The front water inlet pre-interception filtering device of a nuclear power plant pumping station according to claim 1, characterized in that the mesh plate is provided with a mesh frame and mesh pieces installed on the mesh frame, and the mesh frame Both sides are fixed on the chain respectively.
The front water inlet pre-interception filtering device of a nuclear power plant pumping station according to claim 6, characterized in that the mesh plate frame is provided with a sewage bucket at an angle of 10-45° with the horizontal direction.
The front water inlet pre-interception filtering device of a nuclear power plant pumping station according to claim 6, characterized in that the frame is provided with a mesh support and guide mechanism, the mesh frame is provided with guide wheels, and the guide wheels Walk along the screen support guide mechanism.
The front water inlet pre-interception filtering device of a nuclear power plant pumping station according to claim 1, characterized in that the bearing seat is provided with an adjusting rod, and the adjusting rod is provided with a locking nut, which can be tightened or loosened The locking nut adjusts the position of the spindle and the tightness of the endless chain.
The front water inlet pre-interception filtering device of a nuclear power plant pumping station according to any one of claims 1 to 9, characterized in that the frame is arranged in sections in its height direction, and the structures of adjacent sections are adapted and detachable. Assemble.
The front water inlet pre-interception filtering device of a nuclear power plant pumping station according to any one of claims 1 to 9, characterized in that the reserved height of the flow channel between the bottom end of the annular chain and the bottom of the water channel flow channel is Determined by:

S1. Divide the cross-section of the water passage into section 1, section 0 and section 2 in the flow direction. Section 1 is the section upstream of the mesh plate, section 0 is the section at the mesh plate, and section 2 is the section downstream of the mesh plate;

S2. Establish an equation, in which the flow rate flowing through section 0 is the total flow rate of the flow channel:

Q＝Q 1 +Q 2 ＝v 1 A 1 +v 0 A 2 (1)

In formula (1), Q 1 is the flow rate flowing through the pre-interception filter device, Q 2 is the flow rate flowing through the bottom flow channel, v 1 is the flow rate of the pre-interception filter device, v 0 is the flow rate of the bottom flow channel, A 1 is the net flow area of the pre-interception filter device, and A 2 is the flow area of the bottom flow channel;

A 2 =Bh (2)

In formula (2), B is the width of the flow channel, h is the reserved height of the bottom flow channel,

Assuming that the pre-interception filter device is completely blocked, the total head loss (h L1-2 ) is expressed by the head loss of the bottom flow channel:

h L1-2 =Δh 2 (3)

In formula (4), ξ 1 is the resistance coefficient when the cross section suddenly shrinks, ξ 2 = 0.5 (1-h/H 1 ); ξ 3 is the resistance coefficient when the cross section suddenly expands, ξ 3 = (1-h/H 2 ) 2 ;

S3. Determine the channel flow rate Q, channel width B, and channel height H1 according to the actual factory site conditions. According to h L1-2 ≤ 250mm, combine equations (1)-(4) to obtain the reserved height h of the bottom channel. Minimum value required.