JPS6317898Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a mechanical seal for slurry liquid.

When a slurry liquid such as a pulse slurry is used as the sealing liquid, it is known that solid matter gets caught in the sealing surface or clogs the spring, etc., resulting in wear of the sealing surface and poor tracking of the driven ring.

For this reason, conventional methods have been used such as injecting clean liquid from the outside and creating a double mechanical seal.

Although the above-mentioned drawbacks can be overcome by injecting a cleaning fluid, a new problem arises in that the sealing fluid is diluted by the cleaning fluid. On the other hand, if the amount of cleaning liquid to be injected is reduced in order to avoid this, there is a problem in that the above-mentioned drawbacks cannot be solved satisfactorily.

Further, in the case of a double mechanical seal, although there is no problem such as dilution of the sealing liquid, there is a drawback that the structure is complicated and the cost is high.

The present invention has been made to improve the above-mentioned conventional drawbacks, and is intended to prevent clogging due to solids in the slurry liquid with a relatively simple structure.

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a half-sectional view showing an example in which the present invention is applied to a mechanical seal for a slurry pump.
is the rotating shaft, A is the casing, 1 is the fixed ring, 2 and 3
are rotating rings, 2 is a driven ring, 3 is a collar, and 4 is a pressing spring.

A thread 12 is formed on the outer peripheral surface of the rotating rings 2 and 3. The winding direction of this thread 12 is determined according to the direction of rotation of the axis X so as to exert a force in the direction in which the liquid flows from the sealing surface S into the sealing liquid, that is, in the direction of arrow P.

Instead of this thread 12, a blade 13 may be formed as shown in FIG. It is preferable that the blade 13 is formed into a protrusion having a rectangular or trapezoidal cross section as shown in the figure, since this increases the discharge effect. Further, as shown in the figure, it is preferable that the blades 13 be provided obliquely rather than parallel to the axis, and may also be curved in a helical shape. This diagonal direction varies depending on the direction of rotation of the rotary ring, and may be a direction that causes flow in the direction of the arrow in FIG.

In this embodiment, the threads 12 or the blades 13 are formed on both the rotating rings 2 and 3, but they may be provided on either one.

In the case of a slurry pump or the like, there is usually a projection B inside the casing A that protrudes radially inward, such as a socket. Such a protrusion B
It has become clear through experimental research by the present inventors that if there is a solid matter discharge effect by the threads 12 or blades 13 described above, it is significantly inhibited. Therefore, in the present invention, the taper ring 20 is interposed on the surface α perpendicular to the axial direction on the side of the sealing surface S of the protrusion B, and the vertical surface α is connected to the taper surface 20 of the taper ring 20.
It is changed to 0. This taper ring 20 is the third
As shown in the half-cut perspective view of the figure, the ring has a right triangular cross section and is composed of two substantially perpendicular surfaces 201 and 202 and the tapered surface 200, and the surface 201 is aligned with the vertical surface α of the protrusion B. , the surface 202 is brought into close contact with the inner circumferential surface of the casing A, and the tapered surface 200 is exposed into the inside sealing fluid.

With this configuration, the solid matter discharged in the direction of the arrow by the thread 12 or the blade 13 is smoothly discharged along the tapered surface 200 without being stopped by a vertical surface.

The tapered ring 20 can be mounted in various locations, and the one shown in FIG. 4 shows an example in which it is mounted on a vertical plane β rising from the axis X in the radial direction. Further, in this example, a corner a of the casing A is cut out to form a tapered surface a'.

By performing the corner cutting in this manner, the slurry discharge effect is further promoted.

In the above-mentioned embodiment, the following configuration is adopted in order to further increase the slurry discharge effect. That is, an annular protrusion 10 is provided on the casing side corresponding to the collar 3, and a constricted portion 11 is formed between the protrusion 10 and the collar 3. In this embodiment, the protrusion 10 is formed by attaching an annular bush to the casing A, but if there is a neck bush B exactly at the collar 3 position, it may be used. It is desirable that both ends of the protrusion 10 have tapered surfaces as shown.

This constricted portion 11 further promotes slurry discharge.

Further, as shown in FIGS. 1 and 5, the spring 4 is exposed without being covered on the outside and is brought into direct contact with the sealing liquid. The cross-sectional shape of the spring 4 is not round but rectangular as shown in the figure. In this example, it is almost square, but
Shapes such as rectangles and trapezoids are also possible. The winding direction of the spring 4 varies depending on the direction of rotation of the rotating ring, and is the direction that causes a flow in the direction of the arrow in FIG.

However, in this winding direction, if the spring 4 transmits the rotational force from the collar 3 to the driven ring 2, the spring 4 will receive a force in the opening direction, which is not preferable. Therefore, in this embodiment, a plurality of projections 5 and 6 extending in the axial direction are formed at the bases of the driven ring 2 and the collar 3, and rotational force is transmitted by meshing the projections 5 and 6 with each other.

If the pitch of the spring 4 is too wide or too narrow, the screw pumping effect will be reduced, so the pitch is chosen so that the pumping effect is maximized.

By exposing the spring 4 to the sealing liquid in this manner, the spring 4 also functions to discharge the slurry, thereby further enhancing the discharge effect.

As explained above, the mechanical seal of the present invention has a thread or blades formed on the outer periphery of the rotating ring, and a tapered ring is interposed in the protrusion, eliminating a surface perpendicular to the axial direction. The discharge effect is large, and it is possible to eliminate solid matter from clogging the sealing surface.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional view showing one embodiment of the mechanical seal of the present invention, FIG. 2 is a perspective view showing another embodiment of the collar, and FIG. 3 is a perspective view showing the tapered ring cut in half. FIG. 4 is a perspective view showing another embodiment;
FIG. 5 is a front view of the collar, spring, and rotating ring. In the figure, 1... Fixed ring, 2... Driven ring, 3... Collar, 4... Spring, 20... Taper ring.

Claims (1)

[Scope of utility model registration request] A mechanical seal for slurry liquid, characterized in that a thread or blade is provided on the outer circumferential surface of a rotating ring, and a tapered ring is interposed in a surface substantially perpendicular to the axial direction protruding in the radial direction near the thread or blade. .