JPS5821528Y2 - Filtration equipment for purifying high-pressure, high-temperature fluids containing ferromagnetic particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filtration device for the purification of fluids containing ferromagnetic particles, and more particularly to a filtration device for the purification of cooling fluids of nuclear reactors using water.

In pressurized water reactors, pressurized water constitutes the primary fluid and contacts the fuel body before being passed into the steam generator for heating and vaporizing the boiler make-up water or secondary fluid. During circulation within the reactor, this pressurized water picks up particles of iron oxide, which are formed during prolonged contact of the water with the steel parts of the reactor, in the exhaust and steam generators.

In a boiling water reactor, water in the secondary circuit vaporizes on contact with the fuel body.

The steam created in this way powers a turbine.

The condensed water picks up particles within the reservoir.

This water is re-introduced into the reactor and circulated by a circulation pump that forces circulation within the tank by means of an ejector.

Oxide particles tend to become activated and deposit on the fuel assembly upon vaporization.

It is important to note that the amount of oxides in this fluid becomes excessive and that these oxide particles accumulate in the 7>r center direction and then become activated and deposited on the components, significantly promoting surface activation and contamination. To avoid this, it is extremely important to remove these oxide particles from the fluid using a filtration device.

Particles trapped in the filtration device do not circulate within the circuit, thus avoiding contamination of work and maintenance factors that are often present for long periods in the vicinity of nuclear reactor facilities and preventing prohibited irradiation. No radiation exposure.

This fluid purification must, of course, be carried out throughout the operation of the nuclear reactor to ensure continuous purification of the water.

However, there is a difficulty in that this filtration must be performed on water at high temperature and high pressure.

To effect this purification, it has previously been proposed to use an electromagnetic filtration device having a cylindrical envelope filled with balls made of ferromagnetic material, more particularly balls made of steel; A magnetization cycle is applied so that the method captures ferromagnetic particles carried by the fluid.

A filtration device having a magnetizing device surrounding a cylindrical envelope containing the method is generally placed parallel to the pump circulating the water in order to generate a magnetic field that tends to magnetize the method.

A portion of the fluid flow is introduced onto this filtration device.

This introduced portion is generally many orders of magnitude of the total flow rate of the fluid.

In this way, without disturbing the circulation of the fluid in the circuit of the reactor and without thermal degradation (cooling) of the fluid,
The fluid can be purified continuously.

In conventionally used electromagnetic filtration devices, the flow of the fluid to be purified enters at one end of the filtration device via a conduit that passes through one of the bottoms of a cylindrical envelope and passes through a layer of steel balls. It then exits the other end of the filtration device and is circulated within the circuit via a conduit that passes through the other bottom of the cylindrical envelope.

The problem with such filtration devices is that oxide scale tends to continually build up in the same area of the ball mass, resulting in a constant fluid circulation path and suboptimal filtration rates.

That is, the path of the fluid through the layer of spheres is fairly short unless very large and expensive filtration devices are used.

Therefore, the applicant has previously proposed a new type of filtration device that eliminates these drawbacks.

In particular, the applicant's French patent application No. 78-2
No. 8525 describes a filtration device which is extremely efficient, compact and relatively simple in construction.

In such a filtration device, the path of the fluid to be purified is
For the cylindrical envelope of the filtration device, some are radial and some are axial.

In order to obtain an optimal path of the fluid, a deflector is provided inside the filtration device in combination with areas with suitable perforations.

In such a filtration device, the fluid to be purified enters the cylindrical envelope through a conduit passing through the bottom of one of the envelopes and another conduit passing through the bottom of the other cylindrical envelope. drains through the conduit.

To remove one of the bottoms of the cylindrical envelope for loading balls for control or maintenance purposes, the conduit connected to this bottom must be removed.

Note that this inconvenience exists in all devices known and used to date.

In order to facilitate maintenance of the filtration device, it is desirable that the structure of the filtration device, which is hidden inside the cylindrical envelope, be extremely simple and allow easy access to the layer of spheres.

To provide a filtration device to solve the above drawbacks,
It is an object of the present invention, and in order to achieve this object, the present invention comprises a cylindrical envelope disposed with a vertical axis and closed at each end by a hemispherical bottom;
The enclosure encloses steel balls placed on perforated support plates arranged laterally within the enclosure, between which the fluid to be purified passes. the enclosure is connected to an inlet conduit for the fluid to be purified, the inlet conduit opening into the free space below the support plate, and the enclosure is connected to an inlet conduit for the fluid to be purified, the inlet conduit opening into the free space below the support plate; In the filtration device, the filtration device further comprises a magnetizing device for the steel balls disposed on the outer periphery of the envelope, wherein the steel balls are connected to the discharge conduit of the filtration device. housed in a space bounded by a support plate and said upper bottom, said intake conduit for said fluid passing through said lower bottom in a non-vertical direction to a free space below said perforated support plate. Opening into the space and into an area off-center with respect to the lower base, the discharge conduit for the fluid passes through the central part of the lower base and then in the axial direction of the filtration device. penetrate through the interior of the filtration device;
Opening above the upper surface of the layer of steel balls directly below the upper bottom, the discharge conduit is closed at its upper end and in the area above the steel balls where a collection of purified fluid occurs. An orifice shaded on the side of the discharge conduit constitutes a filtration section, and around the filtration section, the upper surface of the layer of steel balls turns itself into a concave surface when the steel balls are magnetized by the magnetization device. It is characterized by being placed along the line.

Fluids, especially in nuclear reactors, are at high pressures and temperatures, making it difficult to perform filtration on such fluids, as oxide scale tends to continually deposit on the steel balls in conventional filtration equipment. In addition, the path of the fluid through the layer of steel balls is quite short unless very large and expensive filtration equipment is used.

Also, in order to remove one of the bottoms of the cylindrical envelope of the filtration device loaded with steel balls for maintenance purposes, the conduit connected to this bottom must be removed.

According to the present invention, in order to facilitate maintenance of the filtration device,
The internal structure of the envelope is extremely simple, and the layer of steel balls is easily accessible.

In addition, when the steel ball is magnetized by the magnetization device, a concave surface is formed on the upper surface of the steel ball layer, and the upper part of the discharge conduit is completely exposed, and the orifice on the upper side of the discharge conduit constitutes a filtration part, and - Can filter fluids.

Also, since the fluid intake is at the bottom of the envelope and not at the center, the fluid can be distributed effectively to the layer of steel balls.

As a result, a compact filtration device capable of purifying high-pressure, high-temperature fluids can be created.

Hereinafter, embodiments of the filtration device of the present invention will be described with reference to the drawings for purification of the primary fluid of a pressurized water nuclear reactor.

In FIG. 1, the filtration device 1 consists of a cylindrical envelope closed by two hemispherical bottoms.

This filtration device will be explained in more detail with reference to FIG. 2, but the filtration device is arranged in a filtration circuit interposed between conduits 2 and 3 of the primary circuit of a pressurized water reactor. ing.

The two sections of conduits 2 and 3 of the above-mentioned secondary circuit are selected such that there is a sufficient pressure difference between the points of the two sections of the circuit to ensure circulation of the primary water within the filtration circuit. has been done.

Two different bifurcation embodiments are shown, for example, in the applicant's French Patent Application No. 78-28525.

In one of these branched embodiments, the conduits 2 and 3 are arranged on either side of the primary pump; in another branched embodiment, the filtration circuit includes a cooling branch at the inlet of the tank and a cooling branch in the upper part of said tank. It is interposed between.

In FIG. 1, the direction of circulation of primary water within the filtration circuit is also shown.

That is, the sludge enters the filtration device through a conduit 4 which is connected via two stop valves 6 and a mechanical filter 7 to the conduit 2 of the secondary circuit.

The mechanical filter is intended to capture suspended matter that may result from the fracture of the process and risk being inadvertently introduced into the fluid.

After passing through the filtration device, the purified primary water is discharged through a conduit 5 which is connected via two stop valves 8 and a mechanical filter 9 to the conduit 3 of the secondary circuit.

A conduit 10 is attached to the conduit 4 as a shunt, which is connected via a valve 11 to a washing container (not shown).

A conduit 12 connected to a reservoir of pressurized water is likewise attached as a shunt to the conduit 5 via a valve 14.

Conduits 11 and 12 are used for cleaning the filtration device, which will be explained later.

Magnetization of the layer in the above method is carried out by magnetizing coils, such as those designated by number 15, located around the periphery of the filter device 1.

Referring to FIG. 2, the filtration device 1 has hemispherical bottoms 21 (lower bottom) and 22 (upper bottom) at each end.
a cylindrical ferrule occluded by
) It consists of 207.

The filtration device is placed in the filtration circuit with its axis vertical.

Each of the bottoms is welded to both ends of the ferrule 20.

Conduit connecting blooms 24 and 25 are arranged on the bottom base 21 so that the conduits 4 and 5, respectively, can be connected by welding.

The connecting bloom 25 extends along a portion of a conduit 26 arranged substantially vertically along the axis of the filtration device 1 .

The conduit 26 is closed at its upper part 27, in which an orifice 28 is bored through its side wall.

The upper part 27 of the conduit 26 thus constitutes a filtration section placed above the upper surface 30 of the layer of spheres 32 and is adapted to filter the secondary fluid.

In effect, upon energizing magnetizing coils such as 15 and 16 located around the periphery of the filtration device 1, the magnetization of the magnetic steel balls constituting the layer 32 creates a curved surface 30 on the top of the layer 32. The upper portion 27 of the conduit 26 is completely exposed.

The upper part 27 of the filtration section or orifice 28 engages within the hollow lower part of a plug 35 which is removably mounted on the upper base 22 of the filtration device 1 .

In this way, conduit 26 is held in an axial position within the filtration device.

At the bottom of the cylindrical ferrule 20 of the filtration device 1, there is a number 3.
Supports such as F and 38 are welded and adapted to support support plates 39 and 40 laterally disposed over the entire cross-section of the filtration device around conduit 26 in place within the filtration device. ing.

The lower plate 39 has holes 41 through its thickness to allow fluid to pass through without undue loss of fluid supply.

This plate 39 also supports an upper plate 40 on which rests the layer of spheres 32.

Further, as seen in FIG. 3, the ball support plate 40 has a groove 50 on its upper surface, which is formed along the chord of the circular plate 40 and comes into contact with the groove.

A cylindrical hole 42 opens inside the groove 50 and is buttoned. The hole is provided throughout the support plate 40 in the lateral direction.

The diameter of the upper hole is also slightly smaller than the width of the groove.

This diameter is also smaller than the diameter of the method to avoid passing the method through the support plate 40.

For example, if the diameter of the method is between 6 and 6.5 mm, the hole has a diameter of 5 mg.

The depth of the groove is selected taking into account the width of the groove and the diameter of the method, so that even if the hole is above the cylindrical hole 42 in the groove, the hole is not blocked by the method. It is designed so that it never happens.

Similarly, the distance d from axis to axis of the groove is selected such that the distance d is not a multiple of the diameter of the method,
Between the grooves, the arrangement of the spheres in one groove does not automatically lead to the arrangement of other spheres constituting the lower curved surface of the layer of spheres.

This filtration device is made of magnetic stainless steel, and the ball support plate is made of non-magnetic stainless steel.

Similarly, the method described above is made of magnetic stainless steel.

Conduit 4, the fluid intake conduit in the embodiment shown in FIGS. 1 and 2, is formed between support plate 39 and bottom 21, passing through bottom 21 and into the filter device. open into the free space of the filtration device.

Therefore, the water to be purified is subjected to pressure on the support plate 39.
and 40 and before being passed through layer 32 of spheres.
First, fill the above free space.

As shown in FIGS. 2 and 4, the magnetization device of the filtration device consists of four coils 15, 16, 17 and 18 containing so-called winding hexagrams and C-shaped magnetic circuits.

Each of the magnetizing coils is energized and includes a cooling circuit, such as the circuit shown in FIG.

The cooling circuit shown in FIG. 4 is provided with a circulation pump 45 and a coolant reservoir 46.

The four electromagnets or coils making up the magnetization device are arranged at 90 degrees around the periphery of the filtration device, with the ends of the C-shaped magnetic circuit close to the cylindrical outer surface of the filtration device.

The operation of this filtration device is as follows.

At the beginning of operation, valves 6 and 8 are opened to connect conduits 2 and 3 of the primary circuit with the filtration circuit.

The difference in water pressure in conduits 2 and 3 provides a circulation of water through conduit 4, the filtration device and conduit 5, which returns to conduit 3 after mackereling.

To start up the filtration device, the electromagnet is magnetized for 1 minute by passing a current through the electromagnet such that the magnetic field without the balls in the filtration device has a value of 3200 oersteds.

The excitation current of the electromagnet is then set to such a value that the magnetic field in the absence of the sphere in the filtration device is 1800 oersted.

A magnetic field gradient is created within the gap existing between the spheres.

Therefore, when the water to be purified flows through the filtration device, -
The magnetic oxide particles suspended within the stub are attracted towards the region of greater magnetic field and deposit on the method.

The flow rate of the primary water entering from the bottom of the filtration device by the intake conduit 4 is controlled by the plates 39 and 4 over the entire cross section of the filtration device.
0, the pressure difference between conduits 2 and 3 causes the water to flow vertically through the filtration device and reach the top of the layer of the above method, where the water, purified free of magnetic oxide particles, enters the sphere. It flows between the upper surface 30 of layer 32 and the top 22 of the filter.

This purified water then passes through a hole or orifice 28 formed in the lateral wall of the upper part 27 of the conduit 26 and is discharged via the conduit 5 into the conduit 3 of the primary circuit.

Mechanical filters 7 and 9 trap suspended matter consisting of ball debris, which is sometimes carried by the primary fluid.

These mechanical filters are interposed between the filtration device and the valve of the circuit to always isolate the filtration device and avoid clogging of the valve by the floating matter.

After some time of operation, the amount of oxide particles contained in the layer of the above method becomes prohibitive and it is necessary to carry out cleaning of the filtration device.

To perform this cleaning, the filtration device is isolated by closing valves 6 and 8, and the layer of the method is demagnetized by a programmed reversal and reduction of the value of the current flowing through the coil.

In this way, the residual magnetic field is brought to an invalid value.

The isolation valve 11 between the filtration device and the waste fluid reservoir is then opened.

During this water discharge, a two-phase emulsion of water and steam forms inside the filtration device, which strips off the oxide particles adhering to the surface of the method.

The two-phase emulsion flows in the opposite direction to the normal flow.

This is because, during normal operation, the partially vaporized and pressurized water is discharged via conduit 4, which is the intake conduit for the pressurized water in the filtration device.

The filtration device is filled with steam and the unvaporized liquid phase is in the waste reservoir.

The equilibrium pressure and temperature depend on the respective volumes of the filtration device and waste reservoir.

Second, valve 11 is closed to isolate the filtration device from the effluent reservoir, and the water in said reservoir is cooled by sprinkling or by operating a cooling circuit arranged around said effluent reservoir.

Valve 14 is then opened to place the filtration device in communication with a storage reservoir of high pressure, high temperature water.

The filtration device is therefore filled with water at high temperature and pressure.

The filtration device is then ready for a new gas expansion.

Three or four gas expansions in succession are necessary to thoroughly clean the filtration device.

Once the cleaning is complete and the filtration device is filled with high pressure, high temperature water, valves 6 and 8 are opened to bring the filtration circuit and the primary circuit back into communication with each other.

If it is desired to inspect the top of the sphere bed and sample a set of spheres while the filter is out of operation, the sphere layer can be accessed by removing the plug 35 which is mounted in the bottom 22 at the top of the filter. Just do as follows.

Therefore, there is no need to remove the primary fluid intake and discharge conduits of the filtration device.

Because of the opening drilled in the bottom 22 and closed with a plug 35, it is also possible to change the set of sphere layers and replace this set immediately before the filtration device is put into operation using a remote control device.

After the filtration device is in operation, the set of spheres has some nuclear radioactivity, so the above considerations are necessary.

No conduit for intake or discharge of the fluid to be purified is attached to the top bottom of the filtration device, and no filtration mechanism is arranged between the top bottom and the top surface of the sphere layer. Therefore, access to the sphere layer is extremely easy.

Furthermore, despite its extremely simple structure, this filtration device has extremely high efficiency.

That is, since there is a plate 39 with holes drilled over the entire surface, the fluid to be treated can be dispersed over the entire surface of the filtration device.

Also, the purified fluid is directed through a filtered device to avoid reintroduction of contaminant particles in the purified fluid.

This purified fluid is directed out of the filtration device by a conduit completely isolated from the layer of the method.

Also, in the embodiments described above, in which the fluid to be purified is introduced into the lower part of the filtration device and the purified fluid is discharged from the filtration part arranged in the upper part of the filtration device,
In the above method, it is avoided that already trapped oxide particles are carried away again by the fluid.

That is, the oxide particles tend to remain stationary due to gravity as the fluid moves upward within the filter bed during purification.

Finally, the provision of a magnetization device with separate electromagnets provides great operational safety.

This magnetization device is thus very easy to remove and therefore provides easy access to the filtration device.

The present invention is not limited to the embodiments described above, and various modifications can be made to the details without departing from the scope of the present invention.

Instead of a spherical bottom as in the embodiments described above, an elliptical bottom can also be used, for example.

Instead of the removable stopper 35, the bottom can be made removable so that the entire surface of the ball layer can be accessed.

The assembly of the support plate and the conduit arranged axially within the filtration device can also be constructed differently from the one described above.

It is also possible to magnetize the sphere substantially uniformly using a magnetization device different from that described above.

Finally, although a particularly preferred application of the inventive device is the purification of pressurized water in nuclear reactors, the inventive device can also be used in different applications in the case of industrial uses of water at high temperatures and pressures (e.g. boiling water). (For water reactors or heavy water moderated reactors)
.

In using the filtration device of the present invention, the water to be purified is introduced through a conduit opening into the free space at the bottom of the filtration device, and the purified water is filtered above the layer of spheres. Although collected at the top of the device, the water is introduced through an axial conduit inside the filtration device, and this water to be purified descends through the bed of spheres by gravity and pressure and after purification into the free space at the bottom of the filtration device. It can also be provided that the clarified water collects in the filtration device, in which case the purified water is discharged through a conduit opening into free space at the level of the bottom of the filtration device.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing the state of the filtration device of the present invention placed in the primary water circuit of a pressurized water reactor, and FIG. 2 is a longitudinal sectional view along the axis of the filtration device of the present invention. FIG. 3 is a perspective view of the ball support plate of the filtration device of the present invention, and FIG. 4 is a perspective view of the filtration device of the present invention and its magnetization device. 4.5...liquid intake button and discharge conduit, 15.
16, 17, 18... Magnetizing coil, 20... Cylindrical part of the envelope, 21.22... Bottom of the envelope, 26...
Vertical conduit penetrating layer of balls, 32... layer of steel balls, 39
．． 40...Support plate for steel balls, 41.42...Hole in support plate, 50...Groove in support plate.

Claims (1)

[Claims for Utility Model Registration] A filtration device for accommodating ferromagnetic particles and purifying a high-pressure, high-temperature fluid, the filtration device being arranged with a vertical axis and having a hemispherical shape at both ends. a cylindrical envelope closed by the bottom of the envelope, said envelope enclosing steel balls placed on a perforated support plate disposed laterally within said envelope; between which the fluid to be purified passes, said enclosure being connected to an intake conduit for the fluid to be purified, said intake conduit extending into the free space below said support plate. the enclosure is connected to a discharge conduit for purified fluid, the filtration device further comprising a magnetizing device for the steel balls disposed around the outer periphery of the enclosure. wherein the steel balls are housed in a space bounded by the support plate and the upper bottom of the filtration device, and the intake conduit for the fluid extends through the lower bottom in a non-vertical direction. through which the discharge conduit for the fluid opens into the free space below the perforated support plate and into an area non-central with respect to the lower bottom; and then penetrate through the interior of the filtration device in the axial direction of the filtration device and open above the upper surface of the layer of steel balls directly below the upper bottom, and the discharge conduit is located at the upper end thereof. In the area above the steel ball where a collection of the thus blocked and purified fluid occurs, a filtration section is formed by an orifice in the side of the discharge conduit, around which the filtration section of the steel ball is formed. A filtration device characterized in that the upper surface of the layer is arranged along a concave surface when the steel ball is magnetized by the magnetizing device.