Patent Description:
Main pump is one of the key equipments of the primary circuit of a PWR nuclear power station. Reliable operation of the main pump plays a vital role in continuous and safe operation of the nuclear power station. For a shaft seal type main pump, a water-lubricated bearing and a shaft seal assembly are provided on the pump body. To ensure cooling and lubrication of the shaft seal assembly and the water-lubricated radial bearing, prevent high-temperature, high-pressure coolant from being conducted to the shaft system above the impeller, and make the water-lubricated radial bearing and the shaft seal assembly operate within an acceptable temperature range, a shaft seal injection water system is provided on the pump body. Under normal circumstances, the shaft seal injection water is provided by upper filling water from a chemical and volume control (RCV) system. In order to ensure normal operation of the main pump when the RCV shaft seal injection water fails, an emergency shaft seal injection water system is usually provided.

The emergency shaft seal injection water system takes water from the main pump housing, cools the water by an external heat exchanger, and injects the cooled water into the shaft seal chamber, so as to provide cooling and lubrication for the shaft seal components and water-lubricated bearings. The medium of the emergency shaft seal injection water system comes from the reactor coolant of the primary circuit which needs to be filtered before being injected into the shaft seal chamber.

A conventional emergency shaft seal water injection filtering device for a main pump adopts hydrocyclone separation technology and includes a container, a conical pipe, an overflow pipe, a cover plate and a sealing ring. The container is provided with an inlet port, an outlet port and a sewage outlet port. The inlet port and the outlet port are welded to the inlet and outlet pipelines respectively. The sewage outlet port is connected to the sewage pipeline through a flange, and an isolation valve is arranged on the sewage pipeline. The cover plate is assembled to the container by bolts. The upper portion of the container, the overflow pipe and the conical pipe jointly form a hydrocyclone seperator. The emergency injection water enters from the inlet along a tangential direction of the conical pipe and forms a swirling motion in the conical pipe. The part of the liquid containing fine particles flows out through the overflow pipe above the conical pipe, enters the upper chamber of the overflow pipe, and flows out along the horizontal discharge port in the chamber. Under the action of centrifugal force, the larger particles settle to the inner wall of the conical pipe. At the same time, due to the driving force of the pressure difference, part of the larger particles in the liquid is discharged from the lower end of the conical pipe into the chamber of the container. Solid particles and impurities are deposited in the container, and the deposits in the container are removed and cleaned regularly by opening the isolation valve on the sewage pipeline.

However, the conventional filtering device for emergency shaft seal injection water of main pump has the following disadvantages: <NUM>) The sewage outlet port of the container is closed, the medium in the container is in a static state, and the effect of hydrocyclone separation is weakened; <NUM>) In the initial stage, the hydrocyclone separation accuracy and efficiency are high. However, with the extension of use time, the concentration of solid particles and impurities in the container become higher and higher, the swirling flow produces a mixing effect in the container, and the solid cannot be deposited on the bottom of the container; <NUM>) Hydrocyclone separator cannot play the role of hydrocyclone separation, thereby reducing the accuracy and efficiency of hydrocyclone separation greatly and, therefore, filtration can not be achieved. <CIT>, <CIT>, <CIT> and <CIT> are relevant prior art documents.

In view of the foregoing, what is needed, therefore, is to provide a filtering device for emergency injection water system of main pump of nuclear power station which has compact structure, desirable safety and reliability, high separation accuracy and separation efficiency, and good settlement performance.

One object of the present invention is to overcome the disadvantages of the prior art and provide a filtering device for emergency injection water system of main pump of nuclear power station which has compact structure, desirable safety and reliability, high separation accuracy and separation efficiency, and good settlement performance. The present invention is described by the subject-matter of claims <NUM>-<NUM>.

According to one embodiment of the present invention, a filtering device for emergency injection water system of main pump of nuclear power station includes:.

According to one aspect of the present invention, the settling separation component includes an umbrella-shaped sewage trap plate, a cone deflector and a filter screen, the umbrella-shaped sewage trap plate and the cone deflector are alternately arranged from top to bottom, the number of the umbrella-shaped sewage trap plates are at least one more than the number of the cone deflectors, and a filtering screen is seated below the lowest umbrella-shaped sewage trap plate.

According to one aspect of the present invention, the cone deflector is fixed to the barrel by welding, the umbrella-shaped sewage trap plate is provided with a number of outriggers, the lowest umbrella-shaped sewage trap plate is directly welded to the barrel through the outriggers, and the remaining umbrella-shaped sewage trap plates are welded to the cone deflector through the outriggers.

According to one aspect of the present invention, the water inlet port is connected with an inlet flange, the water outlet port is connected with an outlet flange, and a bottom of the lower seal head is connected with a sewage outlet flange.

According to one aspect of the present invention, the seat, the upper seal head, the barrel, the lower seal head, the inlet flange, the outlet flange, and the sewage outlet flange are welded to each other.

According to one aspect of the present invention, the inlet flange is connected with a flange of an emergency injection water pipeline, the outlet flange is connected with a flange of an outlet pipeline, and the sewage outlet flange is connected with a flange of a sewage pipeline.

According to one aspect of the present invention, an isolation valve is provided on the sewage pipeline and the isolation valve is in a closed state during normal operation.

According to one aspect of the present invention, the water inlet port has a rectangular structure, a vertical surface of the rectangular is tangent to inner wall of an annular groove in the seat, and the injected water passing through the annular groov enters the conical pipe to form a swirling motion.

According to one aspect of the present invention, the cover plate is assembled to the seat by bolts.

According to one aspect of the present invention, the lower seal head has a tapered structure.

According to one aspect of the present invention, the filter device is made from stainless steel.

Compared with the prior art, the filtering device for emergency injection water system of main pump of nuclear power station of the present invention has the following advantages:.

The filtering device for emergency injection water system of main pump of nuclear power station of the present invention will now be described in detail with reference to the accompanying drawings, in which:.

<NUM>-seat; <NUM>-water inlet port; <NUM>-annular groove; <NUM>-water outlet port; <NUM>-overflow port; <NUM>-chamber; <NUM>-upper seal head; <NUM>-barrel; <NUM>-lower seal head; <NUM>-sewage outlet; <NUM>-inlet flange; <NUM>-outlet flange; <NUM>- sewage outlet flange; <NUM>-cover plate; <NUM>-seal ring; <NUM>-conical pipe; <NUM>-settling separation component; <NUM>-umbrella-shaped sewage trap plate; <NUM>-cone deflector; <NUM>-filter.

In order to make the objective, technical solutions and effects of the present invention clearer, the present invention will be further described in detail below in conjunction with accompanying drawings and embodiments. It should be understood that the embodiments described herein are only for explaining the present invention, not for limiting the scope of the present invention.

Referring to <FIG>, the filtering device for emergency injection water system of main pump of nuclear power station of the present invention includes:.

The seat <NUM>, the upper seal head <NUM>, the barrel <NUM>, the lower seal head <NUM>, the inlet flange <NUM>, the outlet flange <NUM>, and the sewage outlet flange <NUM> are welded to each other to form a pressure boundary of the filtering device.

Referring to <FIG>, an annular groove <NUM> and an overflow port <NUM> are provided in the middle of the seat <NUM>. The water inlet port <NUM> and the water outlet port <NUM> of the seat <NUM> extend to two sides of the seat <NUM>, and the water inlet port <NUM> is located below the water outlet port <NUM>. After the seat <NUM> and the inlet flange <NUM> are welded to each other, the water inlet port <NUM> communicates with the through hole of the inlet flange <NUM>. After the seat <NUM> and the outlet flange <NUM> are welded to each other, the water outlet port <NUM> is communicated with the through hole of the outlet flange <NUM>. The water inlet port <NUM> has a rectangular structure, and the vertical surface of the rectangle is tangent to the inner wall of the annular groove <NUM> of the seat <NUM>.

The upper seal head <NUM> has a tapered structure. The upper part of the upper seal head <NUM> is welded to the lower part of the seat <NUM>, and the lower part of the upper seal head <NUM> is welded to the upper part of the barrel <NUM>. The lower part of the upper seal head <NUM> has an inner diameter corresponding to the outer diameter of the barrel <NUM>.

The barrel <NUM> has a cylindrical structure. The upper part of the barrel <NUM> is welded to the lower part of the upper seal head <NUM>, and the lower part of the barrel <NUM> is welded to the upper part of the lower seal head <NUM>.

A sewage outlet <NUM> is provided at the bottom of the lower seal head <NUM> and is welded to the sewage outlet flange <NUM>. The sewage outlet <NUM> communicates with the through hole of the sewage outlet flange <NUM>. The lower seal head <NUM> has a tapered structure. The upper part of the lower seal head <NUM> has an inner diameter corresponding to the outer diameter of the barrel <NUM>, and the width of the lower part of the lower seal head <NUM> is much smaller than the width of the upper part of the lower seal head <NUM>, which can facilitate the settlement of solid particles and impurities at the lowest position.

The cover plate <NUM> is assembled to the seat <NUM> by bolts. A chamber <NUM> is formed between the cover plate <NUM> and the seat <NUM>. In order to ensure air tightness, a sealing ring <NUM> is provided before the cover plate <NUM> is fixed to the seat <NUM>. Then, the cover plate <NUM> is assembled to the seat <NUM> with bolts, to facilitate the washing and decontamination of the filtering device.

The conical pipe <NUM> is located in a circular chamber formed by the lower part of the seat <NUM> and the upper part of the upper seal head <NUM>. The diameter and height of the circular chamber formed by the lower part of the seat <NUM> and the upper seal head <NUM> are corresponding to those of the conical pipe <NUM>. The conical pipe <NUM> is connected to the seat <NUM> and the upper seal head <NUM> by interference fit. The upper diameter of the conical pipe <NUM> is correponding to the outer diameter of the annular groove <NUM> in the seat <NUM>, and the upper part of the hole of the conical pipe <NUM> communicates with the overflow port <NUM> and the annular groove <NUM> of the seat <NUM> respectively, and the lower part of the conical pipe <NUM> communicates with the upper seal head <NUM>. The top of the overflow port <NUM> communicates with the chamber <NUM> between the cover plate <NUM> and the seat <NUM>, and the chamber <NUM> communicates with the water outlet port <NUM> of the seat <NUM>. The injected water from the water inlet port <NUM> flows into the conical pipe <NUM> via the annular groove <NUM> to form a swirling motion.

The inlet flange <NUM> is connected to a corresponding flange of the emergency water injection pipeline (not shown), the outlet flange <NUM> is connected with a corresponding flange of the outlet pipeline (not shown), and the sewage outlet flange <NUM> is connected with a corresponding flange of the sewage pipeline (not shown). An isolation valve (not shown) is provided on the sewage pipeline (not shown). During normal operation, the isolation valve (not shown) is in a closed state.

Referring to <FIG>, <FIG>, the settling separation component <NUM> is arranged in the barrel <NUM>, the upper part thereof does not exceed the welding point of the barrel <NUM> and the upper seal head <NUM>, and the lower part thereof does not exceed the welding point of the barrel <NUM> and the lower seal head <NUM>. The settling separation component <NUM> includes an umbrella-shaped sewage trap plates <NUM>, a cone deflectors <NUM> and a filter screen <NUM>. Each umbrella-shaped sewage trap plate <NUM> has a sharp top and a horizontally arranged bottom, and the width of the bottom is much larger than that of the top. The upper width of the cone deflector <NUM> is greater than the lower width of the cone deflector <NUM>. The umbrella-shaped sewage trap plate <NUM> and the cone deflector <NUM> are alternately arranged from top to bottom, and the number of the umbrella-shaped sewage trap plates <NUM> is at least one more than the number of the cone deflectors <NUM>. Umbrella-shaped sewage trap plates <NUM> are provided above and below the cone deflector <NUM>. The filter screen <NUM> is arranged under the lowest umbrella-shaped sewage trap plate <NUM>, and the position of the filter screen <NUM> does not exceed the welding point between the barrel <NUM> and the lower seal head <NUM>. In other embodiments of the present invention, according to actual needs, the filter screen <NUM> can be arranged between the umbrella-shaped sewage trap plate <NUM> and the cone deflector <NUM>, can be arranged under the umbrella-shaped sewage trap plate <NUM>, or can be arranged below the cone deflector <NUM>.

Specifically, when only one cone deflector <NUM> is provided, the arrangement of the components is as following: umbrella-shaped sewage trap plate <NUM>, cone deflector <NUM>, umbrella-shaped sewage trap plate <NUM>, and filter screen <NUM>. When the number of cone deflectors <NUM> is two, the arrangement is as following: umbrella-shaped sewage trap plate <NUM>, cone deflector <NUM>, umbrella-shaped sewage trap plate <NUM>, cone deflector <NUM>, umbrella-shaped sewage trap plate <NUM> and filter screen <NUM>. When the number of cone deflectors <NUM> is multiple, umbrella-shaped sewage trap plates <NUM> and cone deflectors <NUM> are arranged alternately in turn, and the umbrella-shaped sewage trap plates <NUM> are arranged below to end the alternation. All the cone deflectors <NUM> are alternately arranged between the umbrella-shaped sewage trap plates <NUM>, and a filter screen <NUM> is arranged at the lowest part.

The filter screen <NUM> has a round holes screen structure and is arranged at a position close to the barrel <NUM> and the lower seal head <NUM>, and the filter screen <NUM> is welded to the inner wall of the barrel <NUM>.

Preferably, the umbrella-shaped sewage trap plates <NUM> and the cone deflectors <NUM> are evenly arranged inside the barrel <NUM>. The cone deflectors <NUM> are fixed on the barrel <NUM> by welding. The umbrella-shaped sewage trap plates <NUM> have a number of outriggers <NUM>. In the illustrated embodiment, four outriggers <NUM> are evenly arranged. The lowest umbrella-shaped sewage trap plate <NUM> is dierectly welded to the barrel <NUM> through the outriggers <NUM>, and the remaining umbrella-shaped sewage trap plates <NUM> are welded to the cone deflector <NUM> via the outriggers <NUM>.

Assembly of the filtering device for emergency injection water system of main pump of nuclear power station of the present invention will be described with reference to <FIG>, in which the order of steps <NUM>) to <NUM>) can be adjusted, and step <NUM>) is finally completed.

Referring to <FIG> and <FIG>, working principle of the filtering device for emergency injection water system of main pump of nuclear power station of the present invention will be detailed as following:
The water inlet port <NUM> and the water outlet port <NUM> of the filtering device for emergency injection water system of main pump of nuclear power station are arranged horizontally, the overflow port <NUM> is arranged in the center of the seat <NUM>, and an annular groove <NUM> is arranged in the middle of the seat <NUM>. The outer diameter of the annular groove <NUM> and the inner diameter of the hole of the conical pipe <NUM> are the same. The emergency shaft seal injection water from the inlet flange <NUM> enters the conical pipe 30along the tangential direction of the inner wall of the annular groove <NUM> in the seat <NUM> under the action of the gravity and pressure to form a swirling motion. A part of the liquid containing trace fine particles flows vertically upwards through the overflow port <NUM> in the seat <NUM>, enters the chamber <NUM> between the seat <NUM> and the cover plate <NUM>, flows out horizontally from the outlet flange <NUM>, and is injected into the shaft seal chamber (not shown), to provide shaft seal injection water for the shaft seal assembly of the main pump.

Under the action of the centrifugal force, the larger particles are settled toward the inner wall of the conical pipe <NUM>. Due to the pressure difference, the larger particles along with the other part of the liquid is discharged from the lower end of the conical pipe <NUM> and enters the container welded by the upper seal head <NUM>, the barrel <NUM> and the lower seal head <NUM>. After entering the container, the liquid containing solid particles and impurities settles around the container under the action of the umbrella-shaped sewage trap plate <NUM>, enters the cone deflector <NUM> to flow toward the center of the container, and passes through the umbrella-shaped sewage trap plate <NUM> and the cone deflector <NUM>, thereby changing the flow direction many times, and finally flows through the filter screen <NUM> to the lower seal head <NUM> of the container.

Since the lower seal head <NUM> has a conical structure, solid particles and impurities finally settle at the lowest position. The settling separation component <NUM> changes the flow direction of the solid particles and impurities, prevents the medium from being mixed, prevents the solid particles and impurities from flowing upward, thereby improving the sedimentation and separation performance, and improving the separation accuracy and separation efficiency of the entire filtering device for emergency injection water system of main pump of nuclear power station. During normal operation, the isolation valve (not shown) on the sewage pipeline (not shown) is in a closed state. During the shutdown and refueling of the nuclear power station, solid particles and impurities are removed and cleaned.

It should be noted that all parts of the filtering device for emergency injection water system of main pump of nuclear power station are made from stainless steel.

Claim 1:
A filtering device for emergency injection water system of main pump of nuclear power station, characterized in that the filtering device comprises:
a pressure-bearing component comprising a seat (<NUM>), an upper seal head (<NUM>), a barrel (<NUM>) and a lower seal head (<NUM>) fixedly connected to each other in sequence from top to bottom, the seat (<NUM>) defining a water inlet port (<NUM>), a water outlet port (<NUM>), and an overflow port (<NUM>) and an annular groove (<NUM>) both in a middle of the seat (<NUM>);
a cover plate (<NUM>) being connected to a top of the seat (<NUM>), the cover plate (<NUM>) and the seat (<NUM>) jointly defining a chamber (<NUM>) therebetween;
a sealing ring (<NUM>) seated between the cover plate (<NUM>) and the seat (<NUM>);
a conical pipe (<NUM>) embedded in the seat (<NUM>) and the upper seal head (<NUM>), an upper diameter of the conical pipe (<NUM>) being corresponding to an outer diameter of the annular groove (<NUM>) in the seat (<NUM>), an upper part of the hole of the conical pipe (<NUM>) communicating with the overflow port (<NUM>) and the annular groove (<NUM>) of the seat (<NUM>) respectively, and a lower part of the conical pipe (<NUM>) communicating with the upper seal head (<NUM>), and emergency shaft seal injection water from the inlet flange (<NUM>) entering the conical pipe (<NUM>) along a tangential direction of the inner wall of the annular groove (<NUM>) in the seat (<NUM>) under the action of the gravity and pressure to form a swirling motion; and
a settling separation component (<NUM>) in the barrel (<NUM>).