JPH0441998A - Magnet pump - Google Patents

Abstract

PURPOSE:To transport gas-liquid two-phase fluid simply and smoothly by separating the fluid into gas and liquid in a pump chamber through centrifugal force due to rotation of an impeller, and by collecting the gas to a central portion of the impeller, and at the same time, by pushing the liquid to the outer portion of the pump chamber. CONSTITUTION:Permanent magnets 31, which serve as a driving magnetic mechanism for turning an impeller by applying magnetic force to permanent magnets 20 buried in the impeller 2, are fixed to a magnet yokes 32. Along the direction of the rotary axis X of the impeller 2 in a central portion of the magnet yoke 32, an inlet passage 49 is formed for communicating a suction port 4 with a pump chamber 19. In addition, a discharge pipe 28, which discharges air bubbles staying near the suction port 4 of the impeller 2, is inserted into a central portion of the magnetic driving mechanism from the suction port 4 of the pump together with a flowing-in passage 49 along the rotary axis X to the position of the impeller 2. Thus, gas and liquid are separated because of the centrifugal force in the portion of the impeller 2. Then, the liquid flows out from a discharge port 5 after being pressurized by means of blades 25 of the impeller 2, and the gas is discharged from the discharge pipe 28 after gathering at the central portion of the impeller 2.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a so-called centrifugal magnet pump in which an impeller embedded with a magnet is rotationally driven by an external magnetic force. Regarding centrifugal magnetic pumps suitable for transferring gas-liquid two-phase fluids containing gas, they are used to pressurize highly foaming chemical solutions such as mixed solutions of sulfuric acid and hydrogen peroxide in semiconductor manufacturing processes.
This invention relates to a magnetic pump suitable for transporting and circulating filtration.

[Conventional technology]

Conventionally, pumps have been used to transfer gas-liquid two-phase fluids in which gas is mixed into the liquid, or fluids with high foaming properties that are solutions near the boiling point.
Positive displacement pumps are often used because they can maintain stable performance. However, positive displacement pumps are not always satisfactory because they need to be large to transfer a large flow of liquid, and the lifespan of the positive displacement pumps themselves is short. There are some devices that have been devised in various ways to transport fluids that are a mixture of gas and liquid.

FIG. 2 is a longitudinal cross-sectional view of a conventional centrifugal pump suitable for gas-liquid two-phase fluids. In the figure, l is a casing, 2 is an impeller housed inside the casing l, 3 is a main shaft for rotating the impeller 2, and 4 is a suction port through which liquid and air bubbles G mix and flow. , 5 is a discharge port through which the liquid and gas G flow out, 6 is a return pipe that returns the liquid from the discharge port 5 side pressurized by the impeller 2 to the suction port 4 side, and 7 is attached to the tip of the return pipe 6. This is the nozzle that was used. This centrifugal pump divides air bubbles G with a relatively large particle size flowing in from the suction port 4 into air bubbles G with a smaller particle size by a water flow from a nozzle 7 arranged upstream near the impeller 2. , so that there is no large impact when the impeller 2 receives centrifugal force.

FIG. 3 is a schematic diagram of a pump device showing another conventional example. In the figure, 8 is a centrifugal pump, a casing 1 of the pump is provided with a suction port 4 and a discharge port 5, and a gas-liquid separator IO is arranged upstream of the suction port 4. Gas-liquid two-phase fluid flowing in from the inflow pipe 16 is separated into gas and liquid due to the difference in specific gravity, and only the liquid flows into the pump 8 . On the other hand, an ejector 15 is arranged downstream of the discharge port 5 of the pump, and sucks the gas accumulated in the upper part of the gas-liquid separator 10 via the exhaust pipe 14. Further, the other end of the condensate pipe 13 branched from the downstream side of the ejector 15 is connected to the gas-liquid separator 10, and a valve 17 is provided at the connection part. The float 12 is operated to open and close depending on the height of the liquid level 11 in the gas-liquid separator 10, and when the liquid level 11 in the gas-liquid separator 10 is low, it opens and the liquid flows from the condensate pipe 13 into the gas-liquid separator IO. The liquid flows into the gas-liquid separator IO to maintain the liquid level 11 high and is exhausted, and the liquid level 1
1 is at a predetermined height or higher, the ejector 15 is closed and evacuated only by the operation of the ejector 15, and the gas-liquid two-phase fluid is pressurized and transferred using a centrifugal pump.

FIG. 4 is a longitudinal sectional view of another conventional example of a magnetic pump using a radial gap type magnetic coupling. In the figure, 1 is a casing, and the casing consists of a suction casing 43 equipped with an inlet 4 and an outlet 5, and a back casing 44. Inside the casing 1, an impeller 2 is rotatably mounted. A pump chamber 19 is formed to house the pump. The impeller 2 has blades 25, a permanent magnet 2o, and a main shaft 3 fixed together, and both ends of the main shaft 3 are rotatable by bearings 24 fixed to the suction casing 43 and bearings 24 fixed to the back casing 44. It is pivoted on. Permanent magnet 4 that gives rotation to the impeller
5 is fixed in an annular shape along the inner circumference of a magnet yoke 48 fastened to a drive shaft 47 of a motor 46, and the impeller 2 rotates by the urging of the motor 46, and the fluid to be transferred flows in from the suction port 4. The pressure is increased by the blades 25 and flows out from the discharge port 5. In this conventional example, the liquid-contact parts of the pump, that is, the casing 1, the impeller 2, and the bearing 24, are made of resin or ceramic to provide corrosion resistance.

This magnet pump is not particularly suitable for transporting fluid containing air bubbles, but is exemplified as a conventional example of an ordinary centrifugal magnet pump.

[Problem to be solved by the invention]

When operating a centrifugal pump that transfers gas-liquid two-phase fluid as described above, when a liquid containing gas G flows into the pump, when the gas mixing ratio (volume ratio) is small, the efficiency is The amount of drop (loss) in the pump head that is commensurate with the mixing ratio is sufficient.

However, when the amount of mixed gas is further increased, impeller 2
Gas gathers in the low-pressure central part of the tube, and this gas gathers in large quantities to block the passage. If gas blocks the passage, the centrifugal force generated by the blades of the impeller acting on the gas is extremely small, so the pump's pressurizing function stops, and eventually the pump becomes inoperable.

The problems with each of the above conventional examples are as follows.

That is, in the conventional example shown in FIG.
By jetting pressurized water from the nozzle 7 sent through the
The bubbles are dispersed in the liquid as smaller bubbles g, allowing the bubbles to pass through the impeller 2 without clumping together, but in centrifugal pumps with high discharge pressure, the nozzle Although it is possible to expect the agitation effect of the pressurized water from 7, that is, the effect of dispersing the bubbles, it is not possible to increase the mixing ratio of bubbles because effective dispersion cannot be achieved with a pump with a low discharge pressure. There was a problem.

In addition, in the conventional example shown in Fig. 3, the gas-liquid separation effect in the gas-liquid separator IO is related to the flow rate and residence time, and when the flow rate of the pump is large, the residence time becomes short and small-sized bubbles are formed. cannot be separated. In such a case, it is necessary to increase the volume of the gas-liquid separator and lengthen the residence time, but this poses a problem in that the pump becomes larger.

Furthermore, when a gas-liquid two-phase fluid is transferred using the magnetic pump shown in FIG. It vibrates violently under load.

In this conventional example, the impeller 2 has a long dimension in the rotational axis direction, and the part 1i25 at one end is the part that receives external force. Since torsional stress is exerted between the parts, the impeller 2 moves in a complicated manner when it receives an external force due to air bubbles.
The bearings 23, 24 will no longer be able to support the load. Further, since the fluid inside the pump chamber 19 is subjected to centrifugal force by the impeller 2, liquid with a large specific gravity gathers on the outer circumferential side, and air bubbles gather on the rotation axis side, so the bearing 23
．． There is a problem in that there is no longer any liquid for lubrication in the portion 24, and in extreme cases, the pump may begin to be damaged due to a liquid shortage phenomenon at the bearings 23, 24.

SUMMARY OF THE INVENTION An object of the present invention is to provide a centrifugal magnetic pump that effectively transfers a gas-liquid mixed fluid in which gas is mixed in the liquid. The object of the present invention is to provide a centrifugal magnet pump that can stably transfer even if there is a large amount of mixed substances.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a magnet pump in which an impeller in which a permanent magnet is embedded is driven to rotate by magnetic force from the outside of the impeller. a pump casing having a pump chamber, one of which is fixed to the casing and the other of which is rotatably housed in the pump chamber of the casing and has a permanent magnet embedded therein; A means for rotationally driving the impeller by applying a magnetic force to a bearing fixed to the impeller and the permanent magnet in the impeller, the means being at a position opposite to the impeller in the direction of the axis of rotation of the impeller. a driving magnetic force mechanism provided in a non-liquid-contacted part of the casing;
an exhaust pipe that guides the gas in the pump chamber to the outside; a fluid inflow path that communicates the suction port with the pump chamber is formed passing through a central portion of the drive magnetic mechanism; It is characterized in that it is disposed to pass through the center of the drive magnetic force mechanism together with the inflow path.

[For production]

Since the present invention is configured as described above, the gas-liquid two-phase fluid flowing in from the suction port receives centrifugal force mainly due to the action of the impeller, so that the gas and liquid are more clearly separated.
Gas staying inside the pump chamber of the casing mainly stays in the area around the rotation axis, while liquid and small air bubbles stay around the outer circumference of the pump chamber and are then discharged. The gas is guided to the outside through the A and is further collected in the vicinity of the rotation axis via an exhaust pipe disposed through the central part of the drive magnetic mechanism together with the inflow path on the suction port side. It is led to the outside by an optional 0 suction means.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of the magnet pump of the present invention.

The pump casing 1 consists of a suction casing la having a suction port 4 for fluid, and a back casing 1b having a discharge port 5 for pressurized fluid. A chamber 19 is formed, a rotating side bearing 23 and a stationary side bearing 24 are respectively fixed to the impeller 2 and the suction casing 1a, and the pump chamber 19 and the suction port 4 are communicated with each other by an inflow path 49. . The materials of these parts constituting the casing 1 must have corrosion resistance against the fluid to be transported depending on the purpose of the pump, but at least the suction casing 1a, which is placed in a magnetic field with high magnetic flux density, must be made of non-magnetic material. It is desirable that there be.

The impeller 2 rotatably housed in the pump chamber 19 is
An annular permanent magnet 20 is glued and embedded in the suction casing la side surface of an annularly molded magnet yoke 21, and after sealing all of these metal members with a quartz cover 22, nylon or fluorine The entire structure is covered with a non-magnetic material such as resin and sealed by known means such as welding or explosion welding, thereby doubly preventing fluid from entering the metal member. Further, the impeller 2 is provided with blades 25 to exhibit a predetermined pump performance, and in the figure, a main plate 26 is attached to form a closed blade in order to increase pump efficiency.

A ceramic fixed side bearing 24 with a spherical concave surface facing the impeller 2 is screwed into the inner surface of the suction casing 1a, that is, the part facing the pump chamber 19, and the fixed side bearing 24 is screwed into the inner surface of the suction casing 1a, that is, the part facing the pump chamber 19.
A rotating side bearing 23 made of ceramic and having a spherical convex surface corresponding to the concave surface of the stationary side bearing 24 facing the concave surface is screwed into the portion of the impeller 2 that faces in the direction of the rotation axis X direction. A groove of approximately 10 microns is formed on either the concave surface or the convex surface, and the two form a single spiral group bearing, and the sliding friction between the bearing 24 and the bearing 23 generates a thrust in the rotation axis X direction. It supports the load and the radial load in the direction perpendicular to the rotation axis X.

Furthermore, a permanent magnet 31 that serves as a drive magnetic force mechanism, which is a means for rotating the impeller by applying magnetic force to the permanent magnet 20 embedded inside the impeller 2, is connected to the non-contactable magnet 31 of the suction casing la. The permanent magnet 31 is disposed in the liquid part, and the permanent magnet 31
is fixed to a magnet yoke 32 rotatably supported by a ball bearing 36, and the magnet yoke 32 is integrally fixed to a rotor consisting of a permanent magnet 40 and a magnet yoke 41 of the motor section, and is connected to a power supply (not shown). The impeller 2 is driven to rotate by energizing a coil 39 wound around an iron core 38 from the
A fluid inflow path 49 that communicates the suction port 5 and the pump chamber I9 is formed along the rotation axis X direction of the impeller 2 at the center thereof.

Further, an exhaust pipe 28 for discharging air bubbles accumulated on the suction port 4 side of the impeller 2 to the outside is connected from the pump suction port 4 side to the inflow path 4.
9 and is inserted through the center of the magnetic drive mechanism along the rotational axis X to the position of the impeller 2. The end of the exhaust pipe 28 that is inserted into the impeller 2 is open, and the end of the exhaust pipe 28 that is connected to the suction port is connected to a known suction means (not shown), such as an ejector-type vacuum pump. Connected to the intake side of Natsch vacuum pumps, etc. In the figure, 29 and 30 are supports for fixing the exhaust pipe 28, and the main plate 26 of the impeller 2 has a center portion bulged outward from the inner end of the blade 25 to form a space 27. However, the structure is such that air bubbles tend to stay in this space 27.

As configured as above, this Macnet pump can be installed with the direction of the rotation axis X perpendicular, that is, with the suction port 4 side facing downward and the discharge port 5 side facing upward, so that the pump can be started. In this case, it becomes possible to prime the pump from the exhaust pipe 28, and when transferring a gas-liquid two-phase fluid,
The liquid mainly flows into the pump chamber 19 due to the centrifugal force of the impeller 2.
On the contrary, the gas is subjected to a separating action and gathers at the center of the impeller 2, and is discharged to the outside from the exhaust pipe 28 by an intake means (not shown).

That is, according to this embodiment, the fluid that flows into the pump in a mixed state of gas and liquid is separated by centrifugal force at the impeller 2, and the liquid is mainly separated by the blades of the impeller 2. 25 and flows out of the pump from the discharge port 5, while the gas remains in the center of the impeller 2,
It is sucked and exhausted to the outside of the pump via the exhaust pipe 28.

In addition, by installing the pump shown in the figure with the suction port 4 side facing downward and the discharge port 5 side facing upward as described above, the exhaust pipe 28 can also perform priming when starting the pump. can.

Further, although not shown, a valve is provided between the exhaust pipe 28 and the intake means, and on the other hand, the rotation speed, current value, etc. of the pump are detected,
By opening and closing the throttle valve or adjusting the opening degree of the throttle valve based on those signals, the load on the intake means connected to the exhaust pipe 28 can be reduced, and furthermore, the load on the intake means connected to the exhaust pipe 28 can be reduced. It can also reduce the amount of liquid that flows out.

〔Effect of the invention〕

As explained above, the magnet pump of the present invention is a magnet pump in which an impeller in which a permanent magnet is embedded is rotationally driven by magnetic force from the outside of the impeller. A pump casing having a pump chamber housed therein; an impeller rotatably housed in the pump chamber of the casing and having a permanent magnet embedded therein; one side fixed to the casing and the other side rotatably housed in the pump chamber of the casing; A means for rotating the impeller by applying a magnetic force to a bearing fixed to the impeller and the permanent magnet in the impeller, and a position facing the impeller with respect to the rotational axis direction of the impeller. a driving magnetic force mechanism provided in a non-liquid-contacting part of the casing, and an exhaust pipe that guides the gas inside the pump chamber to the outside, and a fluid inflow path that communicates the suction port and the pump chamber with the driving magnetic force mechanism. The exhaust pipe is formed to pass through the center of the magnetic force mechanism, and the exhaust pipe and the inflow path are disposed to pass through the center of the drive magnetic force mechanism, and the following effects are obtained.

(b) When transferring a fluid containing a mixture of gas and liquid, the liquid and gas are separated inside the pump chamber by centrifugal force based on the rotation of the impeller, and the gas collects in the center of the impeller. The liquid is guided to the outside of the pump via the exhaust pipe located here, and on the other hand, the pressure of the liquid is increased by the vanes, pushed to the outer circumference of the pump chamber, and transferred to the outside from the discharge port of the pump. Even gas-liquid two-phase fluids, which have been considered difficult, can be transported by centrifugal pumps without any hindrance by simply adding a simple suction means to the end of the exhaust pipe.

(b) Conventionally, when gas-liquid two-phase fluid is transferred using a centrifugal pump, uneven stress acts on the impeller due to the presence of some air bubbles, resulting in a large impact and large excitation force on the impeller. However, in the magnet pump of the present invention, the drive magnetic force mechanism, which is a means for rotationally driving the impeller, and the permanent magnet embedded in the impeller are combined. Since a bearing that supports these loads is disposed between them, the vibration of the impeller, which is a rotating body, can be effectively supported, and the vibration of the pump can be reduced.

(c) If the magnetic pump is installed so that the rotational axis of the impeller is vertical and the positional relationship between the pump chamber and the inflow path is such that the pump chamber faces upward, the installation position of the pump will be on the suction side. If the water level is higher than the water level, air intake from the exhaust pipe can be used to prime the pump when starting it.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of the magnet pump of the present invention, Fig. 2 is a longitudinal sectional view of a conventional example, Fig. 3 is a schematic diagram showing another conventional example, and Fig. 4 is a longitudinal sectional view of yet another conventional example. It is a diagram. 1...Casing, la...Suction casing, 1b
... Back casing, 2... Impeller, 4... Suction port, 5... Discharge port, 19... Pump chamber, 2o...
Permanent magnet, 21... Magnet yoke, 22... Quartz cover, 23... Rotating side bearing, 24... Fixed side bearing, 25... Wing, 26... Main plate, 27... Space Part, 28...Exhaust pipe, 29...Support, 3o...
Support, 31... Permanent magnet, 32... Magnet yoke, 33... Reinforcement plate, 34... Casing cover, 35... Adapter 36... Bearing, 37
... Motor cover, 38 ... Iron core, 39 ... Coil, 40 ... Permanent magnet, 4I ... Magnet yoke, 49 ... Inflow path, X ... Rotating shaft core. Figure 1 Figure 2

Claims (1)

[Claims] 1. A magnet pump in which an impeller in which a permanent magnet is embedded is rotationally driven by magnetic force from outside the impeller, a pump casing having a suction port, a discharge port, and a pump chamber in which the impeller is housed; an impeller that is rotatably housed in the pump chamber of the casing and has a permanent magnet embedded therein; a bearing that is fixed on one side to the casing and on the other side to the impeller; A means for rotationally driving the impeller by applying a magnetic force to the permanent magnet, the drive being provided in a non-liquid-contacted part of the casing at a position facing the impeller with respect to the rotational axis direction of the impeller. A magnetic mechanism and an exhaust pipe that guides the gas in the pump chamber to the outside are provided, and a fluid inflow path communicating between the suction port and the pump chamber is formed by penetrating the central part of the drive magnetic mechanism. A magnet pump characterized in that the exhaust pipe and the inflow passage are disposed so as to pass through the center of the drive magnetic force mechanism.