JPH0366980A - Shaft sealing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a shaft sealing device for underwater rotating equipment such as an underwater centrifugal pump.

[Prior art and its problems] Fixed sealing ring mounting housings in shaft sealing devices for submersible rotating equipment, such as submersible centrifugal pumps, have conventionally been made of cast metal, with pilots formed by machining after casting. Therefore, it is unsuitable for mass production, resulting in high costs and an increase in the weight of the product.

The cross-sectional shape of a conventional cast housing is as shown in Figure 3, but if it were to be made from a metal plate, it would have a cross-sectional shape as shown in Figure 4, which would be difficult to form in one piece using only press working. , requiring joining of parts by welding.

Regardless of whether the housing is made of cast iron or a metal plate, a fixed sealing ring and buffer packing are attached to it, so it is difficult to shorten or shorten the mechanical seal installation length. Since there are so many of them, it is impossible to produce them at low cost.

In particular, in the case of a double seal type shaft seal device that includes both a mechanical seal and a dust seal, the axial length of the device becomes even longer, and there is a problem that it cannot meet the demand for smaller size and lighter weight.

Furthermore, in the above-mentioned double seal type shaft sealing device, the tip of the lip of the lip packing is brought into contact with the outer peripheral surface of the pump shaft to form a sliding sealing surface in the radial direction, which causes wear and tear on the pump shaft. It has the disadvantage of causing Further, since the water pressure gradually acts in a direction that expands the leakage, there is only an initial effect, and the shaft sealing effect decreases over time.

[Object of the Invention] The first object of the present invention is to provide a double seal type shaft seal device in which the housing that supports the fixed sealing ring is made of a metal plate, and the metal plate housing can be joined by welding. The object of the present invention is to provide a small and lightweight product at low cost, with a structure that is unnecessary and can be easily molded only by press working, and with a small number of parts and a reduction in assembly man-hours.

A second object of the present invention is to provide a shaft sealing device that has excellent dust sealing function and does not cause wear on the pump shaft.

[Structure of the Invention] In the shaft sealing device according to the present invention, in the shaft sealing device which is equipped with a mechanical seal and a dust seal, a hard coating layer is annularly formed on the front and back sides of the shaft hole periphery of the mounting housing made of a metal plate. By making the rotary sealing ring on the mechanical seal side face the hard coating layer on the front side, and the lip type packing on the dust seal side facing the hard coating layer on the back side, there is a gap between these two opposing surfaces. In addition, the peripheral part of the shaft hole of the mounting housing made of a metal plate is stamped out in an annular shape to form four rings on the front side and a concave ring on the back side. A hard coating layer is formed in an annular shape on the bottom of the groove and on the surface of the four rings, and the rotary sealing ring on the mechanical seal side is placed in contact with the hard coating layer on the four rings side, and a dust seal is placed on the hard coating layer on the concave ring side. By bringing the side lip-type packings into contact with each other, a sliding sealing surface is formed between these two opposing surfaces.

[Example] To explain the drawings illustrating the embodiment, l is a mounting housing made of a metal plate, and the peripheral part of the shaft hole 2 bored in the plate is stamped out in an annular shape, and a convex ring is formed on the front side. A dowel is formed and a concave ring 3 is formed on the back side thereof. Furthermore, the bottom surface of the groove of the concave ring 3 and the surface of the white layer 4 are coated with ceramics, cemented carbide, or the like to form a hard coating layer 5a, respectively.

5b is formed into an annular shape, and the rotary sealing ring 6a on the mechanical seal side is brought into contact with the hard coating layer 5a on the convex ring side to form a sliding contact surface between the contact surfaces. Reference numeral 7 denotes a pressing spring for pressing the rotary sealing ring 6a against the hard coating layer 5a.

When the present invention is applied to a shaft sealing device for a submersible centrifugal pump, a bearing 9 for supporting the pump shaft 8 is fitted in a concave ring 3' in the upper mounting housing 1', and a bearing 9 for supporting the pump shaft 8 is fitted in the concave ring 3' in the upper mounting housing 1'. Inside the concave ring 3 is the boss portion 1 of the impeller lO.
1 will be inserted.

The lip-type packing 6ba is made of a resilient material such as rubber or synthetic rubber in a V-shape, and the fitting part is fitted onto the pump shaft in the concave ring 3, and the lip part is made of a hard coating layer. By coming into contact with 5b, a sliding sealing surface is formed, and the dust sealing function is controlled. When the pump is driven, the water pressure increases and acts to press the knob portion against the surface on which the hard coating layer 5b is formed, thereby enhancing the dust sealing function.

[Effects] The first effect of the present invention is that the mounting housing 1 made of a metal plate does not require joining of members by welding.
It is obtained by integrally molding using only press processing, and does not require a fixed sealing ring or a buffer packing to support it, so the number of parts is reduced, the installation length of the mechanical seal can be shortened, and the number of assembly steps is also reduced. Small and lightweight products can be provided at low cost.

As the second effect of the present invention, the linobu type packing 6
Since the lip portion b does not come into sliding contact with the pump shaft 8, but with the hard coating layer 5b on the back surface around the shaft hole, the pump shaft 8 will not wear out even after long-term use. In addition, when the pump is driven, water pressure applies the hard coating layer 5b to the lip portion.
This has the advantage that the dust sealing function is enhanced because it acts to press against the surface on which the dust is formed.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional side view of the main part showing an example in which the shaft sealing device of the present invention is applied to a submersible centrifugal pump, Fig. 2 is a longitudinal sectional side view of the main part of the mounting housing in the device of the invention, and Fig. 3 is a conventional casting. A vertical cross-sectional side view of the main parts of a submersible centrifugal pump equipped with a shaft sealing device with a manufactured nozzle structure. Figure 4 is a vertical cross-sectional side view of the main parts showing an example of a metal plate molded into the same structure as a conventional cast nozzle. It is. DESCRIPTION OF SYMBOLS 1... Mounting housing, 3... Concave ring, 4... Convex ring, 5a... Hard coating layer on concave ring side, 5b... Hard coating layer on convex ring side, 6a... Rotating sealing ring, 6b...Lip type pano king.

Claims (1)

[Scope of Claims] [Claim 1] In a shaft sealing device that includes a mechanical seal and a dust seal, a hard coating layer (5a , 5b) are formed into an annular shape, and the rotating sealing ring (6a) on the mechanical seal side is placed in contact with the hard coating layer (5a) on the front side, and the lip type packing on the dust seal side is placed on the hard coating layer (5b) on the back side. A shaft sealing device characterized in that (6b) are brought into contact with each other so that a sliding sealing surface is formed between these two contacting surfaces. [Section 2] In a shaft sealing device that is equipped with a mechanical seal and a dust seal, the peripheral part of the shaft hole of the mounting housing (1) made of a metal plate is hammered out in an annular shape to form a convex ring (4) on the front side. At the same time, a concave ring (3) is formed on the back side of the concave ring (3).
A hard coating layer (5) is applied to the bottom surface of the groove and the surface of the convex ring (4), respectively.
a) (5b) is formed into a ring shape, and a rotary sealing ring (6a) on the mechanical seal side is attached to the hard coating layer (5a) on the convex ring (4) side.
) are placed in contact with each other, and the hard coating layer (5b) on the concave ring (3) side is placed in contact with the lip-type packing (6b) on the dust seal side, thereby creating a sliding sealing surface between these opposing surfaces. A shaft sealing device characterized in that: