JPH0540312Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an impeller support device in a ceramic pump for suctioning and pumping low melting point metals such as zinc, lead, aluminum, etc. in a molten state.

(Prior Art) In a ceramic pump for pumping high-temperature fluid, it is necessary to connect a ceramic impeller to a metal power transmission shaft. For this reason, as shown in Japanese Unexamined Patent Application Publication No. 178900/1984, a device has been proposed in which the shaft of a ceramic impeller is hollow, and bolts are inserted into the hollow to support the impeller on the metal shaft. However, since an opening is formed at the end of the impeller for passing a bolt through, there is a drawback that corrosion is likely to occur due to the fluid being handled. Attempts have therefore been made to seal this opening with another ceramic material, but this has the disadvantage that the sealed portion may peel off, resulting in a lack of reliability and making disassembly and repair difficult. Also, Utsukai Showa 61-
As shown in Japanese Patent No. 32816, a device has also been proposed in which the shaft of a ceramic impeller has a tapered surface, and a hollow metal cylinder is brought in close contact with the outside of the shaft to support the impeller. When a heat-resistant metal of 100% was combined with pressureless sintered silicon nitride, the difference in coefficient of thermal expansion was approximately 6×10 ^-6 /°C, and there was a risk that a gap would occur and the transmission of rotational force would become uncertain. .

(Problems that the invention attempts to solve) This invention solves these conventional problems,
Power is transmitted reliably from the metal power transmission shaft to the ceramic impeller, and dimensional differences in each component due to thermal expansion can be easily absorbed.
It was completed for the purpose of being an impeller support device for ceramic pumps, which is easy to disassemble and reassemble because there are no welded parts.

(Means for Solving the Problems) The present invention uses a ceramic impeller, which has a tapered boss part that widens toward the shaft end, at the lower end of a hollow shaft rotated by a motor through a tapering process. At the same time, a shaft is provided inside the hollow shaft on the impeller side via a rotation prevention member by means of a spring, and a non-circular portion of the end of the shaft on the impeller side is connected to a non-circular recess formed in the boss portion of the impeller. Rotational force is transmitted to the impeller by pressing the shaft toward the shaft, and a protective sleeve made of ceramic is provided around the outer periphery of the hollow shaft.

(Example) Next, the present invention will be explained in more detail with reference to an illustrated example in which the present invention is used in a submerged pump.

Reference numeral 1 is a ceramic casing, 2 is a suction port provided through its lower surface, 3 is a discharge throat, 4 is a ceramic impeller, and 5 is a motor for driving the impeller. The impeller 4 is provided with a tapered boss portion 6 that widens toward the upper end, and this boss portion 6 tapers toward an enlarged diameter portion 8 at the lower end of a metal hollow shaft 7 that is rotated by the motor 5. It is attached via a ring 9. As shown in FIG. 2, this tapered ring 9 is provided with one or more slits 10 extending in the axial direction, and its taper angle is 60° according to the display method shown in JIS B 0612.
The following is desirable.

Since a ring 11 supporting the lower surface of the tapered ring 9 is attached to the lower end of the hollow shaft 7 with a bolt 12, there is no fear that the impeller 4 will fall off downward. The upper end of the hollow shaft 7 is rotatably supported by a base plate 14 via a bearing 13.

In addition, a metal shaft 15 is provided inside the hollow shaft 7.
is provided. This shaft 15 is always urged toward the impeller by a spring 16 built into the upper end of the hollow shaft 7, and a rotation prevention member such as a pin or key driven into the hollow shaft 7 is attached to the upper part of the shaft 15. 17 is provided with a long hole 18 passing through it. This anti-rotation member 17 allows the shaft 1 to
5 is supported so that it can move in the axial direction with respect to the hollow shaft 7 but cannot rotate relative to it.

As shown in FIG. 2, a non-circular portion 19 is formed at the lower end of the shaft 15 on the impeller side, and a corresponding non-circular recess 20 is formed on the upper surface of the boss portion 6 of the impeller 4. Since it is set up,
When the shaft 15 is pressed downward by the spring 16, the non-circular portion 19 is brought into pressure contact with the non-circular recess 20 of the boss portion 6, and the rotational force of the shaft 15 is reliably transmitted to the impeller 4.

Furthermore, a protective sleeve 21 made of ceramic is provided on the outer periphery of the hollow shaft 7 to protect the hollow metal shaft 7 from liquid. This protective sleeve 2
At the upper end of 1, there is a compression ring 22 that is locked to the lower surface of the inner race of the bearing 13, and a disc spring 2.
3 is provided, and the lower surface of the protective sleeve 21 is brought into close contact with the upper surface of the impeller 4. Although the spring 16 may be provided at the lower portion of the shaft 15, it is preferably provided at the upper portion as in the embodiment in order to prevent the elasticity from deteriorating due to heat from the liquid. Further, as the motor 5, it is preferable to use an air motor whose rotation speed can be freely changed in order to change the flow rate.

In the present invention, it is preferable that the ceramic pump of the present invention has its ceramic material made of any one of silicon nitride produced by reaction sintering, silicon nitride produced by pressureless sintering, and silicon carbide produced by pressureless sintering.

(Function) In this structure, the impeller 4 is made of ceramic and has a boss portion 6 that widens toward the end.
is attached to the lower end of the hollow shaft 7 via the tapered ring 9, so when the shaft 15 provided inside the hollow shaft 7 presses the boss portion 6 toward the impeller by the elastic force of the spring 16, impeller 4
The taper ring 9 is in close contact with the boss portion 6 of the impeller 4, so that the impeller 4 can be reliably supported on the lower end of the hollow shaft 7. Furthermore, when the motor 5 is rotated, its rotational force is applied to the hollow shaft 7, the rotation stopper 17, and the shaft 1.
5. It is reliably transmitted to the impeller 4 through the non-circular part 19 at the lower end and the non-circular recess 20 on the upper surface of the boss part, and the impeller 4 can be rotated.

In this way, in the present invention, the part that supports the impeller 4 and the part that transmits rotational force to the impeller 4 are made independent, and if thermal expansion causes the enlarged diameter part 8 at the lower end of the hollow shaft 7 to
Even if a dimensional difference occurs between the impeller 4 and the boss 6, it will be absorbed as an axial displacement of the boss 6 with respect to the taper ring 9, and no excessive thermal stress will be generated in the impeller 4 or the support will loosen. do not have. Moreover, even if such an axial displacement occurs, the shaft 1
Transmission of the rotational force from the impeller 5 to the impeller 4 is ensured regardless of this.

Furthermore, in the present invention, a ceramic protective sleeve 21 is provided around the outer periphery of the hollow shaft 7 to protect it.
Even when used for suction and pressure feeding of highly corrosive high-temperature fluids such as molten metal, the metal hollow shaft 7 and shaft 15
will not be damaged.

(Effects of the invention) As is clear from the above explanation, the present invention not only can reliably transmit power from the hollow metal power transmission shaft and the shaft inside the shaft to the ceramic impeller. Even if there is a dimensional difference due to thermal expansion between the ceramic impeller and the metal hollow shaft, this can be easily absorbed by the tapered part, and since there are no parts fixed by welding etc., it can be easily disassembled. And it is extremely easy to assemble. In addition, the hollow shaft and shaft are protected by a ceramic protective sleeve.
There is no risk of damage even when used with highly corrosive high temperature fluids.

Although the submerged pump that suctions and pressure-feeds molten metal has been described above, the present invention is not limited to this, but includes horizontal centrifugal pumps, axial flow pumps, high-temperature fans, turbochargers, and other high-temperature fluid turbomachinery. It can be applied as a combination of ceramics and metal in the atmosphere.

Therefore, the present invention has extremely great practical value as an impeller support device for a ceramic pump that solves the problems of the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a central vertical sectional view showing an embodiment of the present invention;
FIG. 2 is a perspective view showing the attachment portion between the shaft and the impeller. 4... Impeller, 5... Motor, 6... Boss section, 7... Hollow shaft, 9... Taper ring, 15...
... Shaft, 16 ... Spring, 17 ... Stopping member, 19 ... Non-circular part, 20 ... Non-circular recessed part, 21 ... Protective sleeve.

Claims (1)

[Claims for Utility Model Registration] 1. A ceramic impeller 4 having a tapered boss portion 6 that widens toward the end is attached to the lower end of a hollow shaft 7 rotated by a motor 5 via a tapered ring 9. At the same time as installing the hollow shaft 7
A shaft 15, which is resiliently pushed toward the impeller by a spring 16, is provided inside the shaft 15 via a rotation prevention member 17.
The rotational force is transmitted to the impeller 4 by pressing it against the non-circular recess 20 formed in the impeller 4,
Further, an impeller support device for a ceramic pump is characterized in that a protective sleeve 21 made of ceramic is provided around the outer periphery of the hollow shaft 7. 2. In the ceramic pump according to claim 1, wherein the ceramic material portion is made of any one of silicon nitride produced by reaction sintering, silicon nitride produced by pressureless sintering, and silicon carbide produced by pressureless sintering. Impeller support device.