JPH0227906B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a partition body for a fluid machine, and relates to a partition body for a fluid machine that is disposed in a rotating magnetic field of a fluid machine using a canned motor or a magnetic coupling. The present invention relates to a partition wall that isolates the inside and outside of a system, and that significantly reduces eddy current loss generated by the rotating magnetic field and improves the operating efficiency of the fluid machine.

(Prior art) Generally, fluid machines such as pumps, compressors, and stirrers have shaft seals using gland packings, oil seals, mechanical seals, etc. However, if leakage of the handled fluid is to be avoided, a canned motor or magnetic A so-called glandless fluid machine without a shaft seal is used, such as a net coupling spring.

A groundless fluid machine using a canned motor or a magnetic coupling uses multiphase alternating current to pass through the stator windings in a canned motor, or rotates a driving permanent magnet in a magnetic coupling to drive the inside of a closed fluid system. The structure is such that rotational torque is generated by applying a rotating magnetic field from outside the fluid system through a partition body to a rotor disposed in the rotor and directly connected to a driven part such as an impeller. The inside and outside of the system are shut off, and leakage of the handled fluid to the stator side of the canned motor or the drive section side of the magnetic coupling is completely prevented, so by appropriately selecting the material of the partition wall. Therefore, it can be used for most types of fluids.

By the way, since the bulkhead of the glandless fluid machine is (a) disposed in a rotating magnetic field with high magnetic flux density,
It must be a non-magnetic material rather than a magnetic material that causes magnetic short-circuiting or magnetic shielding.

(b) Since it is placed in a rotating magnetic field with high magnetic flux density,
It must be a high electrical resistance material with low eddy current loss caused by this rotating magnetic field.

(c) Must have the thermal and mechanical strength to withstand the temperature and pressure of the fluid being handled.

(d) Must have chemical strength (corrosion resistance) that can withstand corrosion from the fluid being handled.

(e) It must have a sealing property that prevents the fluid being handled from leaking.

It is desirable that the following five conditions be satisfied.

Conventionally, as the partition of the canned motor,
A non-magnetic, corrosion-resistant thin steel plate such as austenitic stainless steel or Inconel steel is formed into a cylindrical shape because the magnetic space in a radial air type canned motor is cylindrical. Since its magnetic cavity is in the shape of a hollow disk, it is used in the form of a hollow disk.

(Problems to be Solved by the Invention) However, although the partition made of the non-magnetic corrosion-resistant thin steel plate completely satisfies (a), (c), and (e) of the five conditions, Regarding (d), the corrosion resistance against some handling fluids such as hydrochloric acid and diluted acid is poor, and (b)
In this case, a large eddy current loss occurs which accounts for half of the total loss of the motor.

Furthermore, magnetic couplings are generally used in fluid machines with a smaller output than the canned motor, and their partition walls are often made of resin.

However, the partition wall body made only of resin material is
Of the conditions, (a), (b), (d), and (e) are completely satisfied, but because of (c)'s poor thermal and mechanical strength, it is difficult to handle when the fluid to be handled is at high temperature or high pressure. When the thermal and mechanical strength decreases due to the increase in the diameter of the bulkhead due to the increase in output, the occurrence of eddy current loss is unavoidable, so as in the case of the canned motor, a non-magnetic corrosion-resistant steel plate is used. In some cases, a partition made of resin material is used, or a reinforcing body made of the above-mentioned steel plate having the same shape as the partition is closely covered with a partition made of a resin material.

The eddy current loss that occurs in the partition wall is caused by the magnetic field lines of the rotating magnetic field crossing the stationary partition wall at right angles, causing an induced current that flows in a spiral shape in the partition wall, that is, an eddy current, and this eddy current causes the This is the heat loss that occurs in the body. The value of this eddy current loss W _E is calculated using the following formula (1) for a cylindrical partition wall or a disk-shaped partition wall that is continuous over the entire cylindrical surface or flat surface and has no defects and has a constant thickness. can do.

W _E = π/8D ³・L・t・B ²・ω ²・σ(W) ……(1) However, D(m); in the case of a cylindrical partition, the diameter of the partition;
In a disc-shaped partition, it is the average diameter of the magnetic cavity.

L (m): The axial length of the magnetic air in a cylindrical partition, and the difference between the inner and outer radii of the magnetic air in a disc-shaped partition.

t(m): Thickness of partition wall.

B (Wb/m ² ): magnetic flux density of magnetic air.

ω (rad/sec): Angular velocity of rotating magnetic field.

σ (Ω ^-1 /m): Specific electrical conductivity of the partition wall.

Therefore, the partition wall is generally made of a resin material with high voltage resistance, that is, the intrinsic conductivity is generally that of the non-magnetic corrosion-resistant steel plate.
It would be ideal in this respect if the eddy current loss would virtually not occur if it was constructed only from resin material, which is negligible at about 10 ^-20 times, but resin materials are inherently inferior in thermal and mechanical strength. For example, the tensile strength at room temperature is more than one order of magnitude inferior to non-magnetic metal materials such as the steel plate, which has extremely little change in tensile strength due to temperature,
Even if the partition wall has relatively excellent heat resistance, its tensile strength will be halved when the temperature rises to around 100℃, so if thermal and mechanical strength is required as mentioned above, non-magnetic corrosion-resistant material is used for the partition wall. Steel plates have no choice but to be used.
In this case, if the steel plate has no corrosion resistance problem, the steel plate can be used alone as the partition body, but if a resin material is suitable for corrosion resistance, the steel plate is brought into close contact with the resin partition body. used as. However, in any case, the above (1) is present in the steel plate.
As a result, a considerably large eddy current loss occurs, approximately 10 to 20% of the motor output of the canned motor or the transmission power of the magnetic coupling, reducing the operating efficiency of the fluid machine. There is a problem in that the driving parts such as the coupling ring and its driving motor become large and expensive, and the operating cost increases.

The present invention has been made in order to improve the above-mentioned problems, and in view of the thermal and mechanical strength of the bulkheads used in canned motors or magnetic couplings used in fluid machinery, the present invention has been made to improve the above-mentioned problems. Conventionally, a non-magnetic metal material such as a non-magnetic corrosion-resistant steel plate used as a reinforcing material is continuous over the entire surface of a cylindrical or flat surface perpendicular to the lines of magnetic force of a rotating magnetic field and is formed to a constant thickness without defects. Focusing on the fact that large eddy current losses were occurring due to the eddy current loss caused by the bulkhead, we developed a sealing part made of non-magnetic material to prevent fluid leakage and a non-magnetic metal material to increase thermal and mechanical strength. By forming the reinforcing part to reduce eddy current, it has superior thermal and mechanical strength than a partition made only of a non-metallic material such as a resin material,
The eddy current loss is significantly reduced compared to conventional partition walls that use a continuous non-magnetic metal material with a constant thickness without defects or as a reinforcing material for a non-metallic material such as a resin material. It is an object of the present invention to provide a partition body that improves the operating efficiency of a machine.

[Structure of the invention]

(Means for Solving the Problems) A partition wall body for a fluid machine according to the present invention is arranged in a rotating magnetic field of a canned motor or a magnetic coupling used in a fluid machine, and blocks the inside and outside of the fluid system. The partition body is composed of a sealing part made of a non-magnetic material to prevent fluid leakage and a reinforcing part made of a non-magnetic metal material to increase thermal and mechanical strength. is formed so that it is not continuous on a cylindrical surface or plane that is perpendicular to the lines of magnetic force of the rotating magnetic field and passes through the reinforcing portion, and has a defective portion, so as to suppress the generation of eddy currents caused by the rotating magnetic field. This is what happens.

(Function) The partition of the fluid machine of the present invention is made of a sealing part made of a non-magnetic material to prevent fluid leakage and a non-magnetic metal material to increase thermal and mechanical strength, thereby suppressing eddy currents. Because it is constructed with reinforced parts that have defects, the thermal and mechanical strength against the temperature and pressure of the fluid to be handled is greatly improved compared to conventional partitions made only of non-metallic materials such as resin, and the non-magnetic Eddy current loss is significantly reduced compared to conventional partition walls that use non-magnetic metal materials such as corrosion-resistant steel plates alone or as reinforcing materials.

(Example) Next, an example of the present invention will be described based on the drawings.

1 and 2 illustrate the present invention in a radial direction.
An embodiment is shown in which a canned motor pump using a type canned motor is applied. Reference numeral 1 denotes a canned motor pump, and the radial pneumatic canned motor 3 is integrally connected to a centrifugal pump 2 in a fluid-tight manner.

A rotating magnetic field is generated in the magnetic space 6 between the stator 4 of the canned motor 3 and the rotor 5 disposed opposite to the stator 4 due to the multiphase alternating current flowing through the stator winding 7 of the stator 4. In this rotating magnetic field, that is, in the magnetic air 6, a cylindrical partition 8 is closely inserted into the surface of the stator 4 facing the magnetic air, and the cylindrical partition 8 is disposed in the rotating magnetic field, that is, in the magnetic air 6. Leakage to the stator 4 side is prevented.

The cylindrical partition wall 8 is made of a non-magnetic material such as a resin material, and includes a cylindrical sealing portion 10 for preventing leakage of the pump handling liquid, and a non-magnetic metal material 11 such as an austenitic stainless steel wire. A reinforcing portion 12 is wound around the outer circumferential surface of the sealing portion 10 to form a coil shape to increase thermal and mechanical strength.
The steel wire rod 1 of this reinforcing portion 12
The winding pitch P of 1 is selected to be larger than the wire diameter a of the steel wire rod 11 so that adjacent portions do not contact each other, that is, the winding pitch P between the adjacent steel wire rods 11 is
-a is formed, and this gap 13 is a defective portion of the reinforcing portion 12.

According to this embodiment, the cylindrical partition body 8 is
A cylindrical sealing part 10 made of a resin material with excellent chemical strength, and a cylindrical reinforcing part 12 made by winding a steel wire 11 with excellent thermal and mechanical strength into a coil around the sealing part 10. Since the structure is made of ,
It has significantly improved thermal and mechanical strength against pressure, and has superior chemical strength compared to conventional cylindrical partition walls that use non-magnetic metal materials such as non-magnetic corrosion-resistant steel plates alone or as reinforcement materials. , eddy current losses are drastically reduced.

That is, since the sealing part 10 is made of a resin material, eddy current loss does not substantially occur, and the reinforcing part 12 is made of a resin material.
Since it is formed into a cylindrical shape with a gap 13 between P-a so that adjacent parts of 1 do not come into contact with each other, the axial resistance to eddy currents is extremely high, and therefore the generation of eddy currents is extremely suppressed. The eddy current loss is so small that it is not considered a practical problem.

In the above embodiment, since the rotating magnetic field perpendicularly intersects the cylindrical partition 8 only in the magnetic space 6, the reinforcing part 12 of the steel wire 11 as shown in FIG.
may be provided only in the magnetic space 6, and metal rings 14, 14 may be closely inserted on both sides to enhance thermal and mechanical strength.

Further, the cross-sectional shape of the steel wire 11 formed into a coil shape may be arbitrarily selected such as round, square, flat or rectangular, and the material thereof may be any non-magnetic metal material that can be used as a reinforcing material.

The reinforcing portion 12 also connects the steel wire rod 11 to the sealing portion 1.
The fourth
As shown in the figure, when molding the cylindrical sealing part 10 with resin, if the steel wire 11 formed into a coil shape is integrally molded with resin as a core material, that is, the reinforcing part 12
If the cylindrical partition body 8 is constructed so that the sealing portion 10 contains the resin material, the gaps 13 between the steel wire rods 11 are filled with the resin material, and the thermal and mechanical strength of the partition body 8 is improved, although the thermal and mechanical strength is slightly reduced. Moreover, there is no need for means for fixing the adjacent steel wire rods 11 so that they do not come into contact with each other, and the outer circumferential surface of the partition wall body 8 is flush with the other, making it easier to closely insert the partition wall body 8 into the stator 4. It's convenient.

Furthermore, the reinforcing part 12 is formed by forming the steel wire 11 into a coil shape, and, as shown in FIG. A similar effect can be obtained even if the rings 15 are arranged in the axial direction with gaps 16 as defective portions provided between the rings 15.

In addition, the above-mentioned figures 1, 2, 3 and 5
In the embodiment shown in the figure, a sealing part 10 is formed on the liquid contact side (inside) of the cylindrical partition 8, but since the pressure of the liquid handled by the pump is in a vacuum system lower than atmospheric pressure, the partition 8 is When external pressure is applied, or when the bulkhead 8 is required to withstand the external pressure due to the explosion-proof test pressure inside the stator 4 in order to make the canned motor 3 explosion-proof, the sealing portion 10, the reinforcing portion 12, and the sealing The reinforcing portion 12 and the rings 14, 14 may be formed on the liquid contact side (inside) of the partition wall 8 by reversing the positional relationship between the portion 10 and the rings 14, 14.

In this case, the eddy current loss of the partition wall 8 is drastically reduced as in each of the embodiments described above, but the chemical strength is deteriorated because the reinforcing part 12 made of a non-magnetic metal comes into contact with the liquid handled by the pump. , outer and inner 2
The partition body 8 is constructed by sandwiching the reinforcing part 12 between two cylindrical sealing parts 10, 10, or the reinforcing part 12 is integrated as a core material of the sealing part 10 as in the embodiment shown in FIG. It is preferable that the partition wall body 8 is formed by resin molding and enclosed in the sealing portion 10 .

6 and 7 show that the configuration of the reinforcing portion 12 consisting of a plurality of rings 15 in the cylindrical partition 8 shown in FIG. 5 is applied to a canned motor pump using an axial air-type canned motor. An example is shown, and in the axial air type canned motor 17, the magnetic air space 20 between the stator 18 and the rotor 19 is
Since is in the shape of a hollow disk, this magnetic space 〓20
A disc-shaped partition 21 is closely fixed to the magnetic air-opposed surface of the stator 18, and the disc-shaped partition 21 is connected to a disc-shaped sealing part 23 made of a resin material. A reinforcing part 26 is arranged in the magnetic space 20 by providing a gap 25 as a defective part so that a plurality of concentric rings 24 made of a non-magnetic metal material and having diameters successively increased do not come into contact with each other. Discs 27 and 28 are included to increase the strength on the outer diameter side and the inner diameter side of this reinforcing portion 26.

Next, FIGS. 8 and 9 show an embodiment in which the present invention is applied to a magnetic coupling pump using a radial air type magnetic coupling.
In this case, the magnetic space 32 between the driven rotor 30 and the driving permanent magnet 31 made of a permanent magnet or a magnetic hysteresis material is cylindrical, and there are two rotating shafts, an input shaft 33 and an output shaft 34. Due to the structure, a cup-shaped partition 35 is used, and the opening of the partition 35 is set such that its cylindrical portion is disposed in the magnetic space 32 without contacting the driving permanent magnet 31 and the driven rotor 30. A flange portion 36 is clamped and fixed to a pump casing 37 and a frame 38.

The partition body 35 includes a cup-shaped sealing part 40 made of a resin material to prevent leakage of pump handling liquid, and a cup-shaped non-magnetic corrosion-resistant steel plate 41 formed on the outer peripheral surface of the sealing part 40. and a reinforcing part 44 which is closely covered with a filler material 42 on the outer surface and has a large number of small holes 43 as defective parts at least in the portion in the magnetic air 32.

In this embodiment as well, the thermal and mechanical strength is greatly improved compared to a partition wall of the same size made only of resin material, and the eddy current loss occurring in the reinforcing portion 44 is also reduced by providing a large number of small holes 43. As a result, the effective electrical resistance to eddy currents becomes considerably high, so it is significantly reduced compared to the conventional partition wall using the above-mentioned steel plate that is continuous over the entire surface perpendicular to the rotating magnetic field and has no defects and has a constant thickness. .

In this embodiment, in order to provide a large number of small holes 43 in the reinforcing portion 44, the small holes 43 may be punched in a predetermined portion of the steel plate 41, or a commercially available perforated steel plate may be used. Instead of providing the small holes 43, a non-magnetic metal mesh may be used to constitute the reinforcing portion.

Further, FIGS. 11 to 13 show an embodiment in which the present invention is applied to a magnetic coupling pump using an axially air-type magnetic coupling. Since the magnetic space 48 between the driven rotor 46 and the driving permanent magnet 47 is in the shape of a hollow disc, the disc-shaped partition 49 does not come into contact with the driven rotor 46 and the driving permanent magnet 47. The outer diameter portion of the partition wall body 49 is clamped and fixed to the pump casing 50 and the frame 51 so as to be disposed in the magnetic air 48, and the disc-shaped partition wall body 49 is made of a resin material. A reinforcing part 53 made of a non-magnetic metal material and formed in a lattice shape is enclosed in a disc-shaped sealing part 52.

As shown in each of the above embodiments, the reinforcing portion made of a non-magnetic metal material constituting the partition wall in the present invention may be provided with a defective portion so as to suppress the generation of eddy current due to a rotating magnetic field. In the cylindrical partition body 8 shown in FIG.
Even if adjacent portions of the steel wire 11 are brought into contact with each other and tightly wound without providing a This is a defective part of the reinforcing part that suppresses the generation of current, and the sealing part is also made of the resin material shown in each of the above examples, as well as other non-magnetic high electrical resistance materials such as glass and ceramic depending on the pump handling liquid and its temperature specifications. Metal materials may also be used.
Further, the thickness of the non-magnetic metal material, which is continuous and has a constant thickness without defective parts, used in conventional partitions is determined based on the need to maintain thermal and mechanical strength. If, as in the present invention, the thermal and mechanical strength are all provided by a reinforcing part made of non-magnetic metal material with extremely low eddy current loss, the thickness of the non-magnetic metal material in the sealed part will be greater than that of the conventional one. (1)
As shown in the equation, the eddy current loss can be made extremely small in proportion to the thickness t. That is, in the present invention, the sealing portion is not limited to non-metallic materials, but it is also possible to use the same non-magnetic metal material as in the past, but with the material being made much thinner than in the past.

Further, in each of the above embodiments, a pair of sealing parts and a reinforcing part were provided to constitute the partition body, but as shown in FIG. 8 may be configured.

In addition to the canned motor pump and magnetic coupling pump, the present invention can of course be applied to partitions of other glandless fluid machines such as blowers, compressors, and agitators.

〔Effect of the invention〕

As described above, according to the present invention, in a partition that is disposed in a rotating magnetic field of a canned motor or a magnetic coupling used in a fluid machine, and that blocks the inside and outside of a fluid system, this partition It consists of a sealing part made of a non-magnetic material to prevent leakage and a reinforcing part made of a non-magnetic metal material to increase thermal and mechanical strength. By forming it so that it is not continuous on a cylindrical surface or a plane that is perpendicular to the lines of magnetic force of the rotating magnetic field and that passes through the reinforcing part so as to have a defective part, so as to suppress
A partition wall with a conventional structure that has superior thermal and mechanical strength than a partition wall made only of non-metallic materials such as resin, and uses a non-magnetic metal material without defects either alone or as a reinforcing part for non-metallic materials such as resin. A partition wall body for a fluid machine which significantly reduces eddy current loss and improves the operating efficiency of the fluid machine is obtained, and its industrial value is extremely high.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a canned motor pump showing one embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the same bulkhead portion, and FIG. 3 is a canned motor pump showing another embodiment of the present invention. Vertical cross-sectional view of the motor part of the pump, No. 4
Fig. 5 is an enlarged sectional view of a partition body showing other different embodiments, Fig. 6 is a vertical sectional view of a canned motor pump showing another embodiment, and Fig. 7 is a part of the same partition body. 8 is a longitudinal sectional view of a magnetic coupling pump showing another embodiment, FIG. 9 is a perspective view of the same partition body as above, and FIG. 10 is a partition body showing another different embodiment. Enlarged cross-sectional view of 1st
Fig. 1 is a vertical sectional view of a magnetic coupling pump showing another embodiment, Fig. 12 is a front view with a part of the partition wall body cut away, and Fig. 13 is a cross section of the partition body shown in Fig. 12 in the direction of the arrow -. It is a diagram. 8, 21, 35, 49... partition body, 10, 2
3, 40, 52... sealed part, 12, 26, 44,
53...Reinforcement part, 13, 16, 25...Diameter as a defective part, 43...Small hole as a defective part.

Claims (1)

[Claims] 1. In a partition body that is installed in a rotating magnetic field of a canned motor or magnetic coupling used in a fluid machine and blocks the inside and outside of a fluid system, the partition body is made of a non-magnetic material to prevent fluid leakage. and a reinforcing part made of a non-magnetic metal material to increase thermal and mechanical strength. 1. A partition wall for a fluid machine, which is not continuous on a cylindrical surface or a plane that is orthogonal to lines of magnetic force and passes through the reinforcing portion, and has a defective portion.