JPH0538825Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to a canned motor stirrer.

(Conventional technology) Canned motor stirrers have a completely leak-free structure, so they can be used for liquids that do not want to leak outside the stirring tank, such as corrosive liquids, toxic liquids, flammable liquids, and radioactive liquids, as well as pharmaceutical liquids and beverage liquids. Suitable for stirring liquids such as anaerobic liquids where outside air should not be allowed to enter the stirring tank.

The canned motors used in this canned motor stirrer include an axial gap type canned motor and a radial gap type canned motor.
As shown in the figure, the canned motor stirrer 1 can be configured extremely flat and protrudes outward from the stirring tank 2 only slightly. The height up to the installation foundation 3, that is, the installation height h of the stirring tank 2, is small, and when it is installed on the side of the stirring tank 2, the installation interval with adjacent equipment can be shortened. Although the equipment cost is low, it is difficult to increase the size due to problems such as the bearing load due to the magnetic attraction force generated in the axial direction and the pressure resistance of the disc-shaped stator can, and the motor output is 5KW (6 poles) at most. This is the extent to which these are in practical use.

On the other hand, as for the latter stirring device using a radial gap type canned motor, the structure described in, for example, Japanese Utility Model Application Publication No. 49-126675, or the structure shown in FIGS. 5 and 6 is known. In this traditional structure,
The canned motor stirrer 4 has to be elongated in the axial direction, and the part that protrudes to the outside of the stirring tank 2 is quite long. Therefore, when installing it on the bottom of the stirring tank 2, the installation height h of the stirring tank 2 must be increased by a certain amount. If it is installed on the side of the stirring tank 2 as shown in the same figure, the installation interval between adjacent devices must be increased, and the equipment cost of the stirring tank device including the installation space will be high, but it will also increase the size. The advantage is that motors with outputs up to several hundred kilowatts can be easily manufactured.

(Problem to be solved by the invention) Therefore, although the canned motor agitator with a motor output exceeding about 5 KW has the above-mentioned problem caused by the considerable length of the part protruding to the outside of the agitation tank 2, there is no radial gap. type can motor 2
However, the canned motor stirrer 4 that employs this radial gap type canned motor 22 has an additional problem, namely, the
49-126675 or as shown in Figures 5 and 6, when using an axial flow blade such as a marine propeller as the stirring blade 5, the stirring blade 5 is generally removed from the stirring tank 2 to improve stirring efficiency. Since they are arranged at a distance of about one and a half times the diameter of the blades, the overhang of the rotating shaft 6 from the bearing 7 is longer than that of a radial flow blade, and as a result, the shaft diameter of the rotating shaft 6 must be increased due to strength issues. Therefore, the canned motor stirrer 4 becomes relatively expensive, such as the diameter of the bearing 7 becoming larger.

Furthermore, in the conventional canned motor stirrer 4 shown in the above-mentioned Japanese Utility Model Application Publication No. 49-126675 or shown in FIGS. Since the overhang at the center of gravity of No. 4 is quite long and a large gravitational moment due to this overhang acts on the stirring tank 2, there is a risk that the stirring tank 2 may deform. Stirring tank 2
It is necessary to prepare

In addition, in recent years, in order to obtain the optimal stirring effect,
Means for operating the stirrer at a rotation speed lower than the operating rotation speed at the commercial frequency using inverter control is becoming popular;
Alternatively, in the conventional canned motor agitator 4 shown in FIGS. 5 and 6, if the overhang of the rotating shaft 6 from the bearing 7 becomes long, the primary critical rotational speed of the canned motor agitator 4 will often be at the commercial frequency. Therefore, the rotation speed cannot be controlled by the inverter, and in order to control the rotation speed by setting the primary dangerous rotation speed higher than the operating speed at the commercial frequency, the rotation speed of the rotating shaft 6 is When the shaft diameter is increased, the bearing 7 also becomes larger in diameter.
The diameter of the bearing box in which the bearing 7 is installed becomes large and it cannot be installed inside the stator can 11 of the canned motor 22. Therefore, a canned motor 22 with a large inner diameter of the stator 12 is required, which is relatively expensive, and the rotor 16 Since the outer diameter of the rotor 16 also increases, the cylindrical friction loss due to rotation of the rotor 16 in liquid increases dramatically (cylindrical friction loss is approximately proportional to the fifth power of the rotor diameter), resulting in a problem of high operating costs. are doing.

The present invention was created in view of the above problems.
It is an object of the present invention to provide a canned motor stirrer employing a radial gap type canned motor, which has a shorter portion projecting outward from a stirring tank and a shorter overhang from a rotating shaft bearing.

(Means for Solving the Problems) The canned motor stirrer of the present invention is a canned motor stirrer in which stirring blades are attached to the tip of a rotating shaft protruding from a radial gap type canned motor. A flange portion for attaching to the stirring tank is provided around the outer periphery of the stator so that the four halves protrude into the inside of the stirring tank.

Further, in an embodiment of the canned motor stirrer of the present invention having the above-mentioned structure, the mounting flange portion for the stirring tank is welded to the body of the stator frame of the canned motor in a liquid-tight manner, and the above-mentioned canned motor stirrer is attached to the stirring blade side of the canned motor. This adapter is formed by liquid-tightly attaching an adapter consisting of a cylindrical part that covers the outer periphery of the stator of the canned motor and extends toward the side opposite to the stirring blade, and a flange part that is attached to the stirring tank following the cylindrical part.

(Function) In the canned motor stirrer of the present invention, the mounting flange portion to the stirring tank is attached to the outer periphery of the stator such that at least a quarter in the axial direction of the stator of the radially gap type canned motor protrudes into the inside of the stirring tank. As a result, the portion of the canned motor agitator that protrudes to the outside of the agitation tank becomes shorter in accordance with the length of the stator protruding into the agitation tank, and the overhang of the rotating shaft from the bearing can be shortened.

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

FIG. 1 shows an embodiment in which the present invention is applied to a self-circulating type canned motor stirrer, in which a stator core 9 wound with a stator winding 8 is inserted and fixed into a stator frame 10, and the stator core 9 is inserted into a stator frame 10 and fixed. A stator can 11 made of non-magnetic thin metal is inserted and adhered to the inner circumferential surface of the stator frame 1.
A stator 12 is configured by being liquid-tightly welded to both side plates 10b and 10c of the solid child can 1.
1, a rotating shaft 6 is inserted and fixed into a rotor core 14 on which a rotor conductor 13 is attached, and the stator core 14 and rotor conductor 13 are connected to a stator can 15 made of non-magnetic thin metal. A densely coated rotor 16 is disposed opposite the stator 12 with a narrow gap 17 between the stator can 11 and the rotor can 15, and the rotor 16 is arranged in a sleeve. 18a, 18b and thrust collar 19
A radial gap type canned motor 22 is rotatably supported by a front bearing 20 and a rear bearing 21 via a and 19b.

Further, a front bearing box 23 in which a front bearing 20 is mounted and a rear bearing box 24 in which a rear bearing 21 is mounted are connected to the front side plate 10b and the rear side plate 10c of the stator frame 10 through gaskets 25, 25, respectively. The rotating shaft 6 has a stirring blade 5 formed of an axial flow blade at its tip protruding from the front bearing box 23, and an auxiliary impeller at its rear end protruding from the rear bearing box 24. 26 are respectively attached, and an end cover 28 that covers the auxiliary impeller 26 and forms an auxiliary pump chamber 27 between it and the rear bearing box 24 is liquid-tightly attached to the rear bearing box 24 via a gasket 25. There is.

A hollow disk-shaped mounting flange portion 29 through which the stator frame 10 is penetrated is attached to the shaft of the stator 12 from the stirring blade 5 side of the canned motor 22 toward the auxiliary impeller 26 side, which is the side opposite to the stirring blades. The cylindrical body portion 10a of the stator frame 10 is arranged at a position separated by at least one quarter of the length in the direction.
Further, the reinforcing rib 30 of the mounting flange portion 29 is welded to the mounting flange portion 29 and the body portion 10a, that is, at least one quarter of the stator 12 of the canned motor 22 in the axial direction is welded to the body portion 10a. A flange portion 29 for attachment to the stirring tank 2 is provided around the outer periphery of the stator 12 so as to protrude into the inside of the stirring tank 2 .

Further, the other end of a circulation pipe 31 whose one end is connected to the end cap 28 is connected to the mounting flange portion 29, and by the pumping action of the auxiliary impeller 26, the liquid to be stirred in the stirring tank 2 is transferred to the front bearing box 28. It is sucked into the canned motor 22 through a narrow gap 33 between the spacer 32 inserted into the rotary shaft 6, lubricates the front bearing 20, and passes through the gap 17 between the stator can 11 and the rotor can 15 into the canned motor 22. After cooling 12 and rotor 16 and lubricating rear bearing 21,
A self-circulating circulating fluid passage is formed in which the circulating fluid is returned from the auxiliary impeller 26 to the stirring tank 2 via the circulating pipe 31.

The canned motor stirrer of the embodiment configured in this way has a stator 12 of the canned motor 22.
Since at least a quarter of the axis in the axial direction protrudes into the inside of the stirring tank 2 and is attached to the stirring tank 2, the portion protruding to the outside of the stirring tank 2 is shortened by that amount. When installed on the side of the stirring tank 2, the installation height h can be reduced, and when installed on the side of the stirring tank 2, the installation distance between neighboring devices can be shortened, and the equipment cost of the stirring tank device including the installation space can be reduced.

Furthermore, since the stator 12 protrudes into the inside of the stirred tank 2, the overhang of the rotating shaft 6 from the front bearing 20 is shortened. For example, in the embodiment with the dimensional ratios shown in FIG. 1, compared to the conventional example with the dimensional ratios shown in FIGS. 5 and 6, the distance from the stirred tank 2 to the stirring blade 5 is kept constant at about one and a half times its diameter, and the protruding length of the stator 12 into the inside of the stirred tank 2 is set to about the diameter of the stirring blade 5, so that the overhang of the rotating shaft 6 from the front bearing 20 is about half. As a result, the diameter of the rotating shaft 6 can be made thinner than in the conventional example, and therefore the front bearing 20 or both bearings 20, 21 can be made smaller in diameter, and the canned motor agitator can be manufactured at low cost.

Next, FIG. 2 shows another embodiment in which the present invention is applied to a rear injection type canned motor stirrer.
In the above embodiment, the mounting flange portion 29 for the stirring tank 2 is not welded to the stator frame 10, but the mounting flange portion 29 and the front bearing box 23 are attached to the cylindrical portion 3.
4 as an adapter 35, that is, at least a quarter of the stator 12 of the canned motor 22 in the axial direction is connected to the stirring tank 2.
A cylindrical portion 34 is provided on the stirring blade 5 side of the stator 12 so as to protrude inward from the stirring blade 5, and a cylindrical portion 34 that covers the outer periphery of the stator 12 and extends toward the side opposite to the stirring blade.
An adapter 35 consisting of a flange portion 29 for attaching to the stirring tank 2 following the flange portion 29 is attached in a liquid-tight manner, and the auxiliary impeller 26 of the embodiment shown in FIG.
is removed, but a mechanical seal 36 and a shaft seal 38 of a gland packing 37 are provided on the stirring blade 5 side of the front bearing box 23.
A drain pipe 40 that liquid-tightly penetrates the mounting flange portion 29 is connected to the canned motor front chamber 39 between the front bearing 20 and the front bearing 20, and lubricating liquid is supplied from a not-shown source to the rear bearing box 24, which also serves as an end cover. The oil is injected into the canned motor rear chamber 41 formed in the can to lubricate the rear bearing 21, and passes through the gap 17 between the stator can 11 and rotor can 15 to lubricate the stator 12 and rotor 1.
A lubricating liquid passage is formed by a rear liquid injection method in which the lubricating liquid is discharged from the canned motor front chamber 39 to the outside of the agitation tank 2 through a drain pipe 40 after cooling the canned motor 6 and lubricating the front bearing 20.

According to this embodiment, the body 10 of the stator frame 10
Since a does not come into contact with the liquid to be stirred as in the embodiment shown in FIG. 1, there is no need to use a corrosion-resistant metal material such as stainless steel. Since the stator of the canned motor used in other canned motor drive machines such as canned motor pumps and canned motor blowers can be used as is, the cylindrical shape of the adapter 35 is different from the embodiment shown in FIG. 1 in terms of material. 34 is required, and in order to change the protrusion length of the stator 12 inward of the stirring tank 2, another adapter 35 with a different axial length of the cylindrical portion 34 must be prepared, and the mounting flange It is difficult to do this as easily as in the embodiment shown in FIG. 1, in which the axial position of the part 29 can be changed and welded to the body part 10a of the stator frame 10.

As a means for flowing the lubricating liquid into the canned motor 22, if the agitated liquid can be used as a lubricating liquid, the self-circulation method shown in FIG. If a large amount of liquid such as water can be used as a lubricating liquid that will not cause any problem even if mixed into the agitated liquid, the rear injection method shown in Figure 2 may be adopted. If a large amount of lubricating fluid is not available, as shown in FIG. and reaches the can motor rear side chamber 41, and the rest are stator can 11 and rotor can 15.
After cooling the stator 12 and rotor 16 through the gap 17 between the canned motor and lubricating the front bearing 20, it passes from the canned motor front chamber 39 through the circulation pipe 43, is cooled by the heat exchanger 44, and then passes through the circulation pipe 45. An independent circulation system may be adopted in which a lubricant passage is formed, which reaches the canned motor rear chamber 41 through the shaft passage 46 and returns to the auxiliary impeller 42 for circulation.

(Effect of the invention) According to the canned motor stirrer of the present invention, the mounting flange portion to the stirring tank is attached to the stator such that at least a quarter in the axial direction of the stator of the radially gap type canned motor protrudes into the inside of the stirring tank. Since the stator protrudes into the inside of the stirring tank, the portion of the canned motor stirrer that projects outside of the stirring tank becomes shorter.
If the canned motor stirrer is installed on the bottom of the stirring tank, the installation height will be low, and if it is installed on the side of the stirring tank, the installation distance between neighboring devices can be shortened, and equipment costs for the stirring tank device, including installation space, will be low. Furthermore, since the overhang from the rotating shaft bearing can be shortened, the diameter of the rotating shaft can be small, and the bearing can also be small in diameter, allowing the canned motor stirrer to be manufactured at low cost.

In addition, by shortening the outward protruding length of the canned motor agitator from the stirring tank, the mounting flange portion is positioned closer to the center of gravity of the canned motor agitator, so there is no need or only little need to reinforce or thicken the stirring tank to prevent it from deforming due to gravitational moment, and the stirring tank can be made thinner.

In addition, in order to obtain the optimal stirring effect, overhang from the rotating shaft bearing is also used in devices that operate the stirrer at a rotation speed lower than the operating rotation speed at commercial frequencies using inverter control, which has become popular in recent years. Since the primary critical rotational speed exceeds the operating rotational speed at the commercial frequency, it is sufficient to handle the problem.Furthermore, since the rotating shaft diameter is small and the bearings can be small in diameter, it is possible to use a canned motor with a large stator inner diameter. This can prevent the increase in operating costs due to the drastic increase in cylindrical friction loss of the rotor.

Additionally, since the overhang of the rotating shaft from the bearing is shortened and the shaft diameter can be made smaller, the load acting on the bearing due to the weight moment between the stirring blade and the rotating shaft from the stirring blade to the bearing can be significantly reduced. Therefore, the life of the bearing can be extended.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the canned motor stirrer of the present invention, Figs. 2 and 3 are sectional views showing other embodiments of the invention, and Figs. 4 and 5 are respectively sectional views of the conventional canned motor stirrer. A sectional view of a stirred tank device using a canned motor agitator, FIG. 6 is a sectional view of the canned motor agitator. 2... Stirring tank, 5... Stirring blade, 6... Rotating shaft, 10... Stator frame, 10a... Body, 12
... Stator, 22 ... Radial gap type canned motor, 29 ... Mounting flange portion, 34 ... Cylindrical portion, 35 ... Adapter.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a canned motor stirrer in which a stirring blade is attached to the tip of a rotating shaft protruding from a radial gap type canned motor, at least a quarter in the axial direction of the stator of the canned motor is located in the stirring tank. A canned motor stirrer characterized in that a mounting flange portion for attaching to the stirring tank is provided around the outer periphery of the stator so as to protrude inwardly. (2) The canned motor agitator according to claim 1 of the claimed utility model registration, characterized in that a flange for mounting the agitation tank is welded to the body of the stator frame of the canned motor in a liquid-tight manner. (3) Attach an adapter to the stirring blade side of the canned motor, which consists of a cylindrical part that covers the outer periphery of the stator of the canned motor and extends toward the side opposite to the stirring blade, and a flange part for attaching to the stirring tank that follows this cylindrical part. The canned motor stirrer according to claim 1, characterized in that the canned motor stirrer is tightly attached.