JPH0668280B2 - Centrifugal pump liner ring - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liner ring which is used by being fitted into an impeller fitting portion of a casing so as to face a mouth portion of an impeller for a centrifugal pump. It is suitable for use as a liner for a centrifugal pump that uses a plastic impeller made of nylon 66) or the like.

[Prior Art] Conventionally, the impeller fitting portion of the casing of a general-purpose centrifugal pump has a mouth portion 1a of an impeller 1 as shown in a lower half A of Fig. 1 and an enlarged main portion of Fig. 1a. A liner ring 3 is fitted and attached to the casing 2 so as to oppose the sliding portion on the outer peripheral surface thereof, and the liner ring 3 is usually made of a copper alloy.

When the pump is in operation, the fluid discharged from the outlet of the impeller 1 enters between the side surface of the impeller 1 and the casing 2 as indicated by the arrow a, and the outer peripheral surface of the impeller mouth portion 1a and the impeller of the casing are fitted. A slight gap b between the impeller mouth portion 1a and the casing-side liner ring 3 prevents the backflow to the impeller inlet side through the joint portion 2a.

[Problems to be Solved by the Invention]

In the conventional centrifugal pump using the above-mentioned copper alloy liner ring 3, the impeller 1 is made of polyamide 66 (nylon 6).
6) When the copper alloy liner ring 3 and the polyamide 66 impeller 1 are combined using a material that expands with moisture,
Since the impeller has high water absorption due to the property of polyamide 66, the impeller greatly swells, and accordingly, the gap b of the impeller mouth portion 1a decreases.
There is a problem that the mouse part of the impeller is worn out in a short time.

Therefore, it is possible to use a rubber liner ring that is usually considered, but rubber requires a long vulcanization process, a metal core must be used, and a special device for setting (installation) is required. However, there is a problem in that the cost becomes high, and it is not possible to easily provide compatibility with the copper alloy liner ring.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liner ring that is inexpensive and has elasticity and rigidity in a centrifugal pump that uses a material that expands with water such as polyamide 66 for an impeller.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention integrates a plurality of protrusions having a substantially T-shaped cross-section with an enlarged head toward the inside inside an outer ring corresponding to an outer shell made of hard plastic. It is characterized in that the outer shell portion provided with the projection is fitted into the mold, and the elastomer is injected so as to be embedded around the projection and integrally molded.

[Action]

Since the present invention is configured as described above, the outer shell part made of hard plastic and the injection-molded elastomer integrally with the inner part of the outer shell part are integrally provided with the outer shell part, and the cross-section with the head enlarged toward the inner side. The outer shell part made of hard plastic is firmly bonded to the surroundings through the T-shaped projection so as to fill it, and is firmly held firmly to the elastomer integrally molded inside.

When the liner ring integrally formed as described above is used by being fitted into the impeller fitting portion of the metal pump casing,
The elastomer liner ring is very flexible in the free state, but it fits into the fitting part of the metal casing using the elasticity of the polymer material and is set very firmly. It is confirmed that there is no problem. The material of the outer shell is polyamide 66 (nylon).
When 66) was used, it was confirmed that it swells due to water absorption and is even more firmly fixed to the casing, and there is no fear of falling off.

〔Example〕

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

The upper half B of FIG. 1 is a cross-sectional view of the upper half of a centrifugal pump having an elastomer liner ring according to an embodiment of the present invention, and FIG.

In the figure, the liner ring 10 fitted in the impeller fitting portion 2a of the casing 2 with a gap b from the outer peripheral surface of the mouth portion 1a of the impeller 1 is a T-shaped projection with the head enlarged toward the inside. A hard plastic outer ring 11 corresponding to an outer shell portion in which a plurality of 11a are integrally provided, and an elastomer 12 integrally molded inside so as to fill the periphery of the T-shaped projection 11a.
It consists of

The inner surface of the elastomer 12, that is, the impeller mouse portion 1a
A labyrinth 12a is formed on the surface facing the outer peripheral surface of the. A notch (protrusion) 11b is formed on the outer peripheral surface of the hard plastic outer ring 11 corresponding to the outer shell.
The casing 2 is provided with a receiving groove 13 into which the notch 11b is fitted, and by the notch 11b and the receiving groove 13,
The liner ring 10 is designed to prevent the liner ring 10 from falling off the casing fitting portion 2a.

FIG. 3 shows a die 20 for molding an outer ring made of a hard plastic which constitutes a part of the elastomer liner ring of the present invention.
FIG. In the figure, the upper molds 21 and 21a and the lower molds 22 and 22a are positioned and brought into contact with each other by an appropriate means such as a guide rod (not shown), and the inner surfaces of these upper and lower molds (mold plates). The filling port 24 is adapted to communicate with the empty chamber 11A corresponding to the outer ring portion surrounded by the outer surface of the core 23, and the outer peripheral surface of the core 23 is provided inside the outer ring 11. A recess 23ab of the same shape is formed to form the T-shaped projection 11a provided integrally.

When molding the outer ring 11, as shown in the drawing, the upper and lower molds 21, 21a and 22, 22a are clamped, and the injection port
The molten hard plastic raw material is injected from 24 to fill the empty chamber 11A, and after solidification, the upper mold is removed and the molded product of the outer ring 11 is taken out.

FIG. 4 shows a molded product of the hard plastic outer ring 11 taken out from the mold 20 as described above. FIG. 4A is a front view and FIG. 4B is a view of FIG. IV-IV line sectional drawing, the same figure (c) is the principal part expanded sectional view. In the figure,
Inside the hard plastic outer ring 11, a T-shaped protrusion
A plurality of 11a are integrally formed, and a notch 11b is formed on the outer peripheral surface.

FIG. 5 is a cross-sectional view of an integral molding die 30 for integrally molding an elastomer inside the hard plastic outer ring 11 corresponding to the outer shell molded as described above. An elastomer surrounded by the inner surface of the outer ring 11 and the outer surface of the core 33 by inserting (mounting) the molded product of the outer ring 11 shown in FIG. 4 inside the molds (mold plates) 31 and 32. An injection port 34 is communicated with a vacant chamber 12A corresponding to the portion, and an uneven groove 33a corresponding to a labyrinth groove is formed on the outer peripheral surface of the core 33.

In integrally molding the elastomer 12 inside the outer ring 11, as shown in the figure, when the upper and lower molds 31 and 32 are clamped, the melted elastomer raw material is injected from the injection port 34. The raw material is the outer ring corresponding to the outer shell.
The elastomer is fixed so as to fill the area around the T-shaped projection 11a on the inside of 11, and is firmly fixed to the outer shell formed of the outer ring 11. Next, after the elastomer 12 is solidified, the upper mold 31 is removed and the molded product is taken out.

FIG. 6 shows a molded article of the elastomer liner ring of the present invention taken out from the mold 30 as described above, in which FIG. 6 (a) is a front view and FIG. 6 (b) is a view of FIG. VI-VI line sectional drawing, the same figure (c) is principal part sectional drawing. In the figure, the elastomer 1 is embedded inside the hard plastic outer ring 11 corresponding to the outer shell so as to fill around the T-shaped projection 11a.
2 is integrally molded, a labyrinth 12a is formed on the inner surface of the elastomer 12, and a notch 11b is integrally formed on the outer peripheral portion of the outer ring 11.

The elastomer liner ring 10 integrally formed as described above is set in the impeller fitting portion 2a of the metallic pump casing 2 shown in FIG. At this time, the notch 11b on the peripheral surface of the outer ring 11 is fitted into the receiving groove 13 on the inner surface of the casing 2 to prevent the liner ring 10 from falling off.

According to this embodiment, the elastomer 12 is formed by filling the inside of the hard plastic outer ring 11 forming the outer shell with the large projection 11a of the head having a T-shaped cross section.
Is integrally molded, the elastomer 12 is firmly fixed to the outer shell.

Further, since the outer ring 11 forming the outer shell portion is made of hard plastic (polyamide 66), when the pump is used, the plastic material absorbs water so that the metal casing 2 is completely attached and the elastomer 12 has elasticity. In addition, by forming the labyrinth 12a on the surface facing the impeller mouth portion 1a, even if the gap b between the impeller mouth portion 1a is reduced, by giving the elastomer 12 followability, The generated sliding heat and sliding wear can be reduced, and not only the impeller mouse portion 1a but also the life of the impeller 1 can be extended.

In the embodiment described above, the protrusion 11a which is integrally provided on the inner side of the outer ring 11 and whose head is enlarged toward the inner side
Has a substantially T-shaped cross section, and may hold the elastomer 12 integrally formed inside in the radial direction.

Further, the liner ring of the present invention, in the mouse portion of the impeller,
Needless to say, it can be applied to the one with an impeller ring attached.

〔The invention's effect〕

As described above, according to the present invention, a plurality of protrusions whose head portion is enlarged toward the inside are provided inside the outer shell made of hard plastic, and the elastomer is filled so as to fill the periphery of the protrusions. By integrally molding by injection molding, the elastomer can be firmly fixed to the inside of the hard plastic outer ring forming the outer shell.

Further, since the outer ring forming the outer shell is made of hard plastic, not only is the plastic completely attached to the metal casing when the pump is used, but also the liner ring facing the impeller mouth part is used. Since the portion is integrally formed of the elastomer, the elasticity and followability of the elastomer can be provided to reduce the generation of sliding heat and sliding wear with the impeller mouth portion. Therefore, a plastic material that swells due to moisture and heat can be used for the impeller, and the cost can be greatly reduced.

[Brief description of drawings]

The lower half A of FIG. 1 is a sectional view of a main part of a centrifugal pump showing a conventional example, and the upper half B of the same figure is a sectional view of a main part of a centrifugal pump having a liner ring showing an embodiment of the present invention, FIG. 1a. 1 is an enlarged sectional view of an essential part of a lower half A of FIG. 1, FIG. 2 is an enlarged sectional view of an essential part of an upper half B of FIG. 1, FIG. 3 is a sectional view of a molding die for an outer ring, and FIG. ) Is a front view of a molded product of the outer ring, (b) is a sectional view taken along line IV-IV of (a), (c) is a sectional view of a main part, and FIG. 5 is an elastomer injection molding die. 6A is a front view of an elastomer liner ring showing an embodiment of the present invention, and FIG. 6B is a VI-of FIG.
A sectional view taken along the line VI and FIG. 1 ... Impeller, 1a ... Impeller mouse part, 2 ... Casing, 10 ... Elastomer liner ring, 11 ... Outer ring, 11a ... T-shaped projection, 11b ... Notch, 12 ... Elastomer, 12a …… Labyrinth, 13 …… Receiving groove, 20 …… Outer ring molding die, 30 …… Elastomer liner molding die.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kozo Miyazaki 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION (56) References JP 63-297772 (JP, A) JP 60 -100597 (JP, A)

Claims (1)

[Claims] 1. A plurality of projections having a substantially T-shaped cross-section whose head is enlarged toward the inside are integrally provided inside the outer shell made of hard plastic, and the outer shell having the T-shaped projection is formed. A liner ring for a centrifugal pump, characterized in that an elastomer is integrally molded by injection molding so as to fill the periphery of the T-shaped projection inside.