JPS6325229B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a mechanical seal suitable for sealing a rotating shaft, and particularly to a double-ring mechanical seal for low-pressure, low-speed stirring tanks, centrifugal thin film evaporators, etc. It is related to.

[Background of the invention]

In the integral structure fixed ring (fixed ring with two sliding surfaces) shown in Utility Model Publication No. 47-7550, it is important that the two sliding surfaces are located on the same plane (flushness) during the wrapping process. required. This means that when re-wrapping a product that has been used once, the two surfaces lose their coherency due to the difference in the degree of wear, requiring an excessive amount of lapping, and in extreme cases, it may become impossible to re-wrap. It was hot.

[Purpose of the invention]

An object of the present invention is to provide a double-ring mechanical seal that improves the wrapping process, facilitates extraction of seal rings (rotating ring, fixed ring), and has more advanced functions.

[Summary of the invention]

In the present invention, the fixed ring is composed of two rings, and the combined fixed ring forms a cooling cavity,
A fixed ring presser divided in the circumferential direction is attached to the tank lid.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In Fig. 1, 1 is a shaft, 2 is a spring bearing set on the shaft, and an inner rotating ring 3,
The outer rotating rings 4 are inserted in parallel in the radial direction.
These rotating rings 3 and 4 have a built-in shaft sealing spring 5, and the repulsive force thereof prevents them from lifting up during rotation and sliding. The O-ring 6 is enclosed between the spring bearing 2 and the inner and outer rotating rings 3 and 4, and seals the sealant inside the shaft sealing chamber. Further, an O-ring 7 is inserted between the spring bearing 2 and the shaft 1 to seal the fluid in the tank. 12 is an inner fixing ring, 13 is an outer fixing ring, and 10 is an O-ring, which prevents leakage at the dividing surface of the inner and outer fixing rings 12 and 13, each having an L-shaped cross section, and allows leakage to flow through the formed cavity. Seal the cooling water. Reference numeral 9 denotes an O-ring inserted between the external fixing ring 13 and the tank lid to seal the fluid in the tank. Thus, a shaft sealing chamber is formed by the spring bearing 2, the inner and outer rotating rings 3 and 4, the inner and outer fixed rings 12 and 13, and the O-rings 6 and 10, and seals the sealant therein.

O-ring 8 in Figure 1 and O-ring 11 in Figure 2
is a sealing O provided at the opening of the inner fixed ring 12 that penetrates into the shaft sealing chamber and the cooling water chamber.
It's a ring. Sealant inlet/outlet pipe 14 in Fig. 2
is fixed to the external fixing ring 13 by welding.

The rotation of the shaft 1 is transmitted to the spring bearing 2 by a set screw 17, and then to the inner and outer rotating rings 3, 4 by a torque pin 18. The inner and outer fixing rings 12 and 13 are screwed together by a set screw 15 (Fig. 1).
It is fixed to the fixed ring presser 16 by a torque pin 19. The inner and outer fixing rings 12 and 13 having an L-shaped cross section are directly cooled by cooling water flowing through the hollow portions thereof.

The fixed ring holder 16 is screwed to the tank lid with a bolt 20, and this holder is divided into two circumferential parts and has a flange shape that can be easily attached and detached. Therefore, the inner and outer fixed rings 12 and 13 can be easily taken out by removing the fixed ring holder, and since there is no need to remove the tank lid, it is easy to inspect the sliding surfaces of these seal rings. It is a structure that can be used.
Furthermore, although it was impossible to clean the inside of the jacket with indirect cooling, in this embodiment it is possible to disassemble and clean the cooling chamber, thereby making it possible to prevent deterioration of the cooling effect due to limescale and the like. Therefore, by using a semi-balance type for the outer rotating ring, it is possible to reduce the sliding surface pressure P, and the sliding speed V
By giving P inversely proportional to the increase in
Among the PV values, which are said to affect seal performance,
They can be made equal in the outer rotation ring. In addition, by forming a fixed ring with two sliding surfaces by combining the two rings into one ring corresponding to one sliding surface, the amount of wrapping of the sliding surface can be reduced by 2. This can be reduced compared to when both surfaces are processed at the same time, and re-wrapping after use can be performed in the same way as conventional mechanical seals.
Maintenance costs can be significantly reduced.

By creating a cavity in the combined cross section of the two seal rings and creating a structure that allows water to flow through it, cooling efficiency is significantly improved compared to indirect cooling methods using jackets, etc., and compared to the conventional double ring mechanical method. In seals, sealant was mainly supplied using a forced circulation method, but it has become possible to use a method in which the sealant is pressurized and sealed using a fixed ring with a built-in direct cooling chamber in this example, and it has been widely used in operation. Cost can be reduced.

〔Effect of the invention〕

According to the present invention, the wrapping process and the extraction of the seal ring are facilitated, and there is an effect that the seal ring has a more advanced function as a mechanical seal.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a mechanical seal according to the present invention, and FIG. 2 is a sectional view of a sealant inlet/outlet pipe and a portion where a torque pin is used. 1...Shaft, 2...Spring bearing, 3...Inner rotating ring, 4
...Outer rotating ring, 5...Shaft sealing spring, 6-11...O
Ring, 12... Internal fixing ring, 13... External fixing ring,
14... Sealant inlet/outlet pipe, 15... Set screw,
16... Fixed ring holder, 17... Set screw, 18...
Torque pin (for rotating ring), 19... Torque pin (for fixed ring), 20... Bolt.

Claims (1)

[Claims] 1. A combination of inner and outer fixed rings corresponding to the inner and outer rotating rings in a double-ring mechanical seal whose sliding surfaces are inspected by removing the inner and outer rotating rings and the inner and outer fixed rings. This double-ring mechanical seal is characterized by forming a cooling cavity with a fixed ring retainer divided in the circumferential direction and attached to the tank lid.