JP2012026348A - Pump sealing mechanism, and pump with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing mechanism capable of preventing abrasion and damage, even if a liner ring and a rotor contact each other, while keeping a clearance between the liner ring and the rotor small, and also capable of significantly reducing noise.SOLUTION: The sealing mechanism includes: a liner ring 6 placed in proximity to a pump rotor 1; a liner ring housing 7 and a liner ring cover 8 forming a space 10 for radially movably housing the liner ring 6; and protrusions 12 provided in at least either of the liner ring housing 7 and the liner ring cover 8 and facing a side of the liner ring 6. An axial movement of the liner ring 6 is substantially restrained by the protrusions 12.

Description

  The present invention relates to a seal mechanism of a pump provided with a liner ring, and more particularly to a pump seal mechanism that eliminates sliding between a liner ring and a pump impeller and reduces noise. The present invention also relates to a pump provided with such a sealing mechanism.

  The pump is generally provided with a seal mechanism having a liner ring so that the liquid pressurized by the rotating impeller does not leak to the low-pressure suction side. This seal mechanism includes a both-liner type having a liner ring on both the front side (suction side) and the back side (discharge side) of the impeller, and a single liner type having a liner ring only on the front side of the impeller. A so-called press pump composed of a pressed metal member (for example, a stainless steel plate) is usually provided with a one-liner type seal mechanism.

  The liner ring is arranged to face the wear ring on the impeller through a minute gap, and prevents the liquid from flowing from the high pressure side to the low pressure side. A conventional sealing mechanism will be described with reference to FIG. FIG. 1 is a schematic view showing a seal mechanism of both liner types. In the centrifugal pump shown in FIG. 1, two liner rings 103 are arranged on the front side and the back side of the impeller 100, and these two liner rings 103 are fixed to the pump casing 106. The impeller 100 is provided with two wear rings 104. The liner ring 103 and the wear ring 104 are disposed to face each other, and a gap is formed between the inner peripheral surface of each liner ring 103 and the outer peripheral surface of each wear ring 104. Note that the liner ring 103 may be disposed directly opposite the impeller without providing the wear ring 104.

  The gap between the liner ring 103 and the wear ring 104 is preferably as small as possible from the viewpoint of preventing liquid leakage. In a normal case, although it depends on the diameter of the pump, the gap between the liner ring 103 and the wear ring 104 is about 0.3 mm. However, if the gap between the liner ring 103 and the wear ring 104 is made too small, the wear ring 104 of the impeller 100 rotating with the shaft 101 may cause deflection of the shaft 101, misalignment between the impeller 100 and the pump casing 106, or the like. As a result, the liner ring 103 comes into contact with the liner ring 103 and wears. On the other hand, when the gap between the liner ring 103 and the wear ring 104 is increased, the high-pressure liquid discharged from the impeller 100 easily flows into the suction side, thereby reducing the pump performance.

  The seal mechanism shown in FIG. 2 has a configuration including a liner ring 103 that is movable in the radial direction and the axial direction in order to solve the above-described problems. That is, the liner ring 103 is accommodated in a space formed by the liner ring housing 110 and the liner ring cover 111, and the liner ring 103 is movable in the radial direction and the axial direction in this space. In this example, the wearer ring is not provided, and the liner ring 103 is disposed directly facing the impeller 100.

  In the floating liner ring structure shown in FIG. 2, the liner ring 103 and the impeller 100 are worn because the liner ring 103 moves in the radial direction and the axial direction even if the impeller 100 contacts the liner ring 103 during the pump operation. There is nothing to do. Therefore, the gap between the liner ring 103 and the impeller 100 can be set small.

  However, the floating liner ring 103 that can move freely in the radial direction and the axial direction has a problem that it makes contact with the liner ring housing 110 and the liner ring cover 111 and generates noise during the pump operation.

JP-A-2005-207402 International Publication No. 99/17026 Pamphlet

  The present invention has been made in view of the above-mentioned conventional problems, and can reduce wear and damage even when the liner ring and the rotating body come into contact with each other while keeping the gap between the liner ring and the rotating body small. An object of the present invention is to provide a seal mechanism that can reduce noise significantly.

  In order to achieve the above-described object, one aspect of the present invention is a pump sealing mechanism, a liner ring disposed in proximity to a rotating body of the pump, and the liner ring being movable in a radial direction. A liner ring housing and a liner ring cover forming a space for accommodating, and a protrusion provided on at least one of the liner ring housing and the liner ring cover and facing a side surface of the liner ring, the shaft of the liner ring Directional movement is characterized by being substantially constrained by the protrusion.

In a preferred aspect of the present invention, the liner ring cover is disposed on a high pressure side of the liner ring, and the protrusion is provided on the liner ring cover.
In a preferred aspect of the present invention, the protrusion is three or more protrusions.
In a preferred aspect of the present invention, the liner ring is made of a resin.

  Another aspect of the present invention is a pump comprising the sealing mechanism, an impeller, a shaft to which the impeller is fixed, and a pump casing in which the impeller is accommodated.

  According to the present invention, the movement in the axial direction is substantially restrained by the protrusion while allowing the movement of the floating liner ring in the radial direction, so that fluttering of the liner ring can be suppressed and noise can be reduced. Furthermore, since the contact area between the protrusion and the liner ring is small, free movement of the liner ring in the radial direction is ensured. Therefore, even if the clearance between the liner ring and the rotating body is reduced, the wear on them can be reduced.

It is a schematic diagram which shows an example of the conventional sealing mechanism. It is a schematic diagram which shows the other example of the conventional sealing mechanism. It is a mimetic diagram showing a seal mechanism concerning one embodiment of the present invention. FIG. 4A is a view of the liner ring cover and the protrusion as viewed from the axial direction, and FIG. 4B is a view of the liner ring cover and the protrusion as viewed from the radial direction. FIG. 5A to FIG. 5E are diagrams showing examples of the shape of the protrusions. It is a table | surface which shows the result of the noise experiment of the pump provided with the sealing mechanism shown in FIG. 3, and the pump provided with the conventional sealing mechanism shown in FIG. FIG. 7A and FIG. 7B are plan views showing examples of grooves formed on the side surface on the low pressure side of the liner ring. It is a figure which shows the other structural example of the sealing mechanism which concerns on embodiment of this invention. It is sectional drawing which shows the pump provided with the sealing mechanism which concerns on one Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 3 is a schematic view showing a sealing mechanism according to an embodiment of the present invention. The seal mechanism of this embodiment is used for a pump that transfers liquid, such as a centrifugal pump. As shown in FIG. 3, the sealing mechanism includes a liner ring 6, a liner ring housing 7, and a liner ring cover 8. The liner ring 6 is disposed so as to surround the fluid inlet of the impeller 1 that is a rotating body. The impeller 1 is rotationally driven by a driving source (not shown) such as a motor via a shaft 2, and the liquid flows in the impeller 1 as indicated by an arrow as the impeller 1 rotates.

  The liner ring housing 7 and the liner ring cover 8 form an annular space 10 that accommodates the liner ring 6. The liner ring housing 7 has an annular recess slightly larger than the liner ring 6, and the liner ring cover 8 is fixed to the liner ring housing 7 so as to cover the recess. The liner ring cover 8 is disposed in the high pressure region in the pump casing 3 and is located on the high pressure side of the liner ring 6. On the other hand, the liner ring housing 7 is disposed in the low pressure region in the pump casing 3 and is located on the low pressure side of the liner ring 6. In this embodiment, the liner ring housing 7 is configured integrally with the pump casing 3, but the liner ring housing 7 may be configured separately from the pump casing 3.

  The liner ring 6 is disposed in a space 10 formed by the liner ring housing 7 and the liner ring cover 8 so as to be movable in the radial direction. The outer diameter d1 of the space 10 is larger than the outer diameter d2 of the liner ring 6, and therefore, the liner ring 6 has a difference (d1-d2) between the outer diameter d1 of the space 10 and the outer diameter d2 of the liner ring 6. It can move in the radial direction. In the present specification, the axial direction is a direction along the rotation axis of the impeller (rotating body) 1, that is, the axis 2, and the radial direction is a direction perpendicular to the axial direction.

  Three protrusions 12 that face the side surface of the liner ring 6 are provided on the side surface of the liner ring cover 8. The side surface of the liner ring cover 8 and the side surface of the liner ring 6 are surfaces perpendicular to the axial direction, and these are opposed to each other. The protrusion 12 protrudes from the side surface of the liner ring cover 8 toward the side surface of the liner ring 6. Therefore, the protrusion 12 is disposed between the liner ring 6 and the liner ring cover 8.

  4A is a view of the liner ring cover 8 and the protrusions 12 as viewed from the axial direction, and FIG. 4B is a view of the liner ring cover 8 and the protrusions 12 as viewed from the radial direction. As shown in FIGS. 4A and 4B, the three protrusions 12 are arranged on the side surface of the annular liner ring cover 8 at equal intervals in the circumferential direction. Although one protrusion or two protrusions may be provided instead of the three protrusions, it is preferable to provide three or more protrusions in order to prevent the liner ring 6 from flapping in the axial direction. Furthermore, it is preferable to arrange three or more protrusions at equal intervals.

  The height of the protrusion 12, that is, the dimension in the axial direction of the protrusion 12 is such a height that the movement of the liner ring 6 in the space 10 in the axial direction is substantially restrained. Accordingly, there is little play in the axial direction of the liner ring 6, and the axial movement of the liner ring 6 is substantially constrained by the protrusion 12. Here, “substantially restrained” means that there is a gap between the liner ring 6 and a member adjacent to the liner ring 6 so as to have a fitting tolerance (for example, a gap fit to an intermediate fit). Say. For example, the gap δ between the side surface of the liner ring 6 and the side surface of the liner ring housing 7 obtained from the tolerance of the design dimensions of the liner ring 6, the liner ring housing 7 and the liner ring cover 8 is plus 0.3 mm to minus 0.3 mm. Preferably, this gap δ is in the range of plus 0.2 mm to minus 0.2 mm, and ultimately the gap δ is 0 (zero). If the gap δ is too large, the liner ring 6 flutters and noise is generated. If the gap δ is too small, the liner ring 6 is fixed, and the liner ring 6 cannot move in the radial direction. Will contact and wear.

  The shape of the protrusion 12 is preferably a shape that reduces the contact area with the liner ring 6. More specifically, it is preferable that the protrusion 12 and the side surface of the liner ring 6 are substantially in point contact. For example, as shown in FIG. 3, the protrusion 12 preferably has a hemispherical shape. Other shapes include a cylindrical shape having a hemispherical tip as shown in FIG. 5A, a conical shape as shown in FIG. 5B, a cylindrical shape as shown in FIG. Examples thereof include a conical shape having a hemispherical tip as shown in FIG. 5D and a spherical shape as shown in FIG. Since the contact area between the protrusion 12 and the liner ring 6 having the shape shown in FIGS. 3 and 5A to 5E is small, the protrusion 12 hardly restrains the radial movement of the liner ring 6. The free movement of the liner ring 6 in the space 10 in the radial direction is maintained.

  The liner ring cover 8 is preferably composed of a metal such as stainless steel, a ceramic such as SiC, a polymer material such as plastic, or a combination of a plurality of different materials. In the present embodiment, the liner ring cover 8 is made of stainless steel (SUS), and the punch is hit with a hammer or the like from the back surface (the surface opposite to the side surface on which the protrusions 12 are formed) of the liner ring cover 8. A protrusion 12 is formed on the liner ring cover 8. The protrusion 12 and the liner ring cover 8 may be formed integrally or may be formed separately.

  The inner peripheral surface of the liner ring 6 is disposed close to the outer peripheral surface of the impeller 1. In order to prevent wear due to contact with the rotating impeller 1, the liner ring 6 is made of a highly wear-resistant material. In the present embodiment, the liner ring 6 is made of resin. In the resin liner ring 6, even when pressed against the protrusions 12, the movement of the liner ring 6 in the radial direction is not easily restrained by the elastic deformation of the liner ring 6. Furthermore, in order to reduce the frictional resistance between the liner ring 6 and the protrusions 12, it is preferable that the liner ring 6 is made of polytetrafluoroethylene or Teflon (registered trademark).

  In this embodiment, the inner peripheral surface of the liner ring 6 is disposed directly opposite to the outer peripheral surface of the fluid inlet of the impeller 1, but a wear ring is attached to the impeller 1 as shown in FIG. The liner ring 6 may be disposed so as to face the wear ring. In this case, the impeller 1 and the wear ring constitute a rotating body of the pump.

  Next, the result of the noise experiment of the pump provided with the seal mechanism according to the present embodiment will be described with reference to the table of FIG. FIG. 6 is a table showing the results of a noise experiment of the pump having the seal mechanism shown in FIG. 3 and the pump having the conventional seal mechanism shown in FIG. The clearance δ of the seal mechanism according to the present embodiment is about 0.1 mm. As shown in the table of FIG. 6, the noise of the pump provided with the conventional seal mechanism was about 65 dB, whereas the noise of the pump provided with the seal mechanism according to the present embodiment was about 50 dB. In particular, in the pump provided with the seal mechanism according to the present embodiment, there was no annoying periodic noise caused by flapping of the liner ring 6. From this experimental result, it was found that the sealing mechanism of the present invention has a sufficient effect for reducing noise.

  By providing the protrusion 12 that supports the liner ring 6 from the axial direction, there is almost no axial gap between the liner ring 6 and the liner ring housing 7. Accordingly, the liner ring 6 does not flutter in the axial direction, thereby realizing a seal mechanism with less noise. Further, since the radial movement of the liner ring 6 is not restrained by the protrusions 12, the wear of the liner ring 6 can be reduced even if the gap between the liner ring 6 and the impeller 1 (or wear ring) is reduced. it can.

  Instead of the liner ring cover 8, the protrusion 12 may be provided on the liner ring housing 7, or the protrusion 12 may be provided on both the liner ring cover 8 and the liner ring housing 7. However, it is preferable to arrange the protrusions 12 only on the liner ring cover 8 arranged on the high-pressure side as shown in FIG. This is because the liner ring 6 is pressed against the low-pressure side liner ring housing 7 by the pumping action of the impeller 1, and therefore the liner ring 6 is unstable in the annular space 10 when the liner ring housing 7 has the protrusion 12. It is because it may become a proper posture.

  Here, a groove extending in the radial direction or spiral may be provided on the side surface of the liner ring 6 on the low pressure side. FIG. 7A and FIG. 7B are plan views showing examples of grooves formed on the side surface of the liner ring 6 on the low pressure side. A plurality of grooves 15 are formed on the side surface of the liner ring 6 on the low pressure side. Here, the side surface on the low pressure side of the liner ring 6 is a surface facing the side surface of the liner ring housing 7. When the impeller 1 rotates, a part of the liquid in the high pressure region passes through the gap between the liner ring 6 and the liner ring housing 7 and flows into the low pressure region. At this time, the negative pressure of the liquid on the low pressure side enters the groove 15, and the side surface on the low pressure side of the liner ring 6 comes into close contact with the side surface of the liner ring housing 7 like a suction cup. Accordingly, there is no play in the axial direction of the liner ring 6, and noise during operation of the pump is further reduced. Instead of the liner ring 6, the groove may be formed on the side surface of the liner ring housing 7 that faces the side surface of the liner ring 6 on the low pressure side.

  FIG. 8 is a diagram illustrating another configuration example of the sealing mechanism according to the present embodiment. In this example, in addition to the suction side of the impeller 1, the liner ring 6, the liner ring housing 7, the liner ring cover 8, and the protrusion 12 are disposed on the back side of the impeller 1. The liner ring cover 8 is disposed close to the back surface of the impeller 1, and the protrusion 12 is disposed on the side surface of the liner ring cover 8 so as to face the side surface of the liner ring 6. Also in this example, as shown in FIG. 8, it is preferable to arrange the protrusions 12 only on the liner ring cover 8 arranged on the high pressure side.

  FIG. 9 is a cross-sectional view showing a pump provided with a seal mechanism according to the present embodiment. This pump is a centrifugal pump provided with a single stage impeller 1. The impeller 1 is connected to a motor M via a shaft 2 and is driven to rotate by the motor M. A gap between the pump casing 3 and the shaft 2 is sealed with a mechanical seal 17. A seal mechanism 20 according to the present embodiment is provided so as to surround the fluid inlet of the impeller 1. In this example, the liner ring housing 7 (see FIG. 3) is provided separately from the pump casing 3.

  When the impeller 1 is rotated by the motor M, as indicated by an arrow, the liquid is sucked into the pump casing 3 from the suction port 3a, and after the pressure is increased by the rotation of the impeller 1, the liquid is discharged from the discharge port 3b. According to the pump provided with the seal mechanism 20 according to the present embodiment, since the impact at the time of contact between the liner ring 6 and the liner ring housing 7 is reduced, noise can be reduced. Of course, the sealing mechanism according to the present invention can be applied not only to the single-stage centrifugal pump shown in FIG. 9 but also to a multi-stage centrifugal pump.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

DESCRIPTION OF SYMBOLS 1 Impeller 2 Shaft 3 Pump casing 6 Liner ring 7 Liner ring housing 8 Liner ring cover 12 Protrusion 20 Seal mechanism

Claims (5)

A pump sealing mechanism,
A liner ring disposed close to the rotating body of the pump;
A liner ring housing and a liner ring cover forming a space for movably accommodating the liner ring in a radial direction;
A protrusion provided on at least one of the liner ring housing and the liner ring cover and facing a side surface of the liner ring;
The seal mechanism according to claim 1, wherein the axial movement of the liner ring is substantially restrained by the protrusion.   The seal mechanism according to claim 1, wherein the liner ring cover is disposed on a high-pressure side of the liner ring, and the protrusion is provided on the liner ring cover.   The sealing mechanism according to claim 1, wherein the protrusions are three or more protrusions.   The seal mechanism according to any one of claims 1 to 3, wherein the liner ring is made of a resin. A seal mechanism according to any one of claims 1 to 4,
Impeller,
A shaft to which the impeller is fixed;
And a pump casing in which the impeller is accommodated.

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