JPH0649976Y2 - Static double mechanical seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a static double mechanical seal having two sets of static mechanical seals in which a seal ring axially pressed by a spring does not rotate.

[Conventional technology]

Conventionally, there is a static double mechanical seal as shown in FIG.

That is, this double mechanical seal is
A non-rotating seal ring 10 mounted on the inner periphery of a flange 102 fixed to 101 so as to be airtight and axially movable, and biased by coil springs 106 in opposite axial directions.
5a, 105b and the shaft 10 inserted through the inner circumference of the housing 101
It is attached to the outer periphery of 3 through collars 108a and 108b in an airtight state, rotates with the shaft 103, and has mating rings 107a and 107b that are axially opposed to the seal rings 105a and 105b. It consists of a pair of static mechanical seals 104a, 104b, and seals sliding surfaces 109a, 109b between the seal rings 105a, 105b and mating rings 107a, 107b.
Is formed.

Replace the seal rings 105a and 105b with the mating rings 107a and 107b.
A plurality of the coil springs 106 to be pressed by are arranged in the circumferential direction (multi-spring type), and the spring holding portions 110 formed on the inner circumference of the flange 102, respectively.
Held in. 111 is a drive pin that is implanted in the outer end surface of the flange 102 to prevent rotation of the seal ring 105b, 112a and 112b are implanted in the collars 108a and 108b, and rotational force from the shaft 103 is applied to the mating rings 107a and 107b, respectively. It is a knock pin that transmits. The seal ring
105a is also provided with a detent means (not shown).

[Problems to be solved by the device]

However, the conventional static double mechanical seal described above has the following problems.

The first problem is that the seal ring 105b is the drive pin 11
It is locked by 1 but the other seal ring 1
Since 05a and the coil spring 106 are not integrally assembled with the flange 102, they are difficult to handle. The second problem is that since this type of static double mechanical seal is generally a multi-spring type, slurry liquid or high-viscosity liquid to be sealed in the intermediate chamber 113 between both mechanical seals 104a and 104b. If it leaks, the solid content of the liquid adheres to and accumulates on each coil spring 106 and spring hole 110, impairing the operability of the seal rings 105a and 105b, and possibly decreasing the sealability.

In order to solve such a problem, a cartridge type structure in which non-rotating seal rings 105a and 105b are held in a case attached to the inner circumference of the housing 101 in a retaining state, and instead of the coil spring 106, It is effective to use a single coil spring extending so as to surround the outer circumference of the shaft 103, but in this case, there is a problem that the intermediate chamber 113 for enclosing the lubricating oil is reduced in the radial direction.

[Means for Solving the Problems]

In order to eliminate the above-mentioned drawbacks, the static double mechanical seal according to the present invention comprises a holder that is closely fixed to the inner circumference of the housing and a non-rotating two that are fitted in the inner circumference of the holder and are aligned in the axial direction. One seal ring and two shafts that are externally fixed to the shaft that is inserted into the housing and rotate, and extend between the two seal rings that axially confront each seal ring and both seal rings and surround the outer circumference of the shaft. A single coil spring that urges both seal rings in opposite directions in the axial direction and presses them against the mating rings, and a range provided in the holder so that the coil spring can extend in the axial direction is defined by the two seal rings in the holder. It is equipped with a stopper mechanism that restricts the space between the mating parts of the two, and the holder is positioned between the mating parts of both seal rings to open the required number of openings. With part is formed, on the inner peripheral surface of the housing which is in close contact with the holder, in which recesses are formed in corresponding positions between the fitting portion between the two seal rings.

[Action]

According to the present invention, the non-rotating seal rings of both mechanical seals receive a load so as to be pushed out from the inner circumference of the holder to both sides in the axial direction by a single coil spring provided between the both seal rings. The maximum length that the coil spring can extend in the axial direction is limited by the stopper mechanism between each fitting position with both seal rings in the holder, so that it is not installed between both mating rings on the outer circumference of the shaft. Even in the state, the stationary side including the holder, both seal rings and the coil spring does not fall apart. Moreover, the so-called one-coil spring type, which uses a single coil spring extending so as to surround the outer circumference of the shaft, is used. It is not necessary to locate the holder in the intermediate chamber between them.

Further, the opening formed in the holder between the fitting portions with both seal rings faces the concave portion formed at the position corresponding to the fitting portions with both seal rings on the inner peripheral surface of the housing. Since the intermediate chamber has a shape enlarged to the outer periphery of the holder, the volume of the intermediate chamber becomes sufficiently large.

〔Example〕

Hereinafter, the static double mechanical seal according to the present invention,
Description will be given with reference to the embodiment shown in FIG.

In FIG. 1, reference numeral 1 is a housing of the device, 2 is a shaft inserted into an inner peripheral hole of the housing 1, and 3A and 3A.
B is a mechanical seal provided between the housing 1 and the shaft 2 in a state of being lined up in the axial direction.

Both mechanical seals 3A and 3B are held on the inner circumference of the housing 1 via a holder 4, and are urged in opposite axial directions by a single coil spring 8 extending so as to surround the outer circumference of the shaft 2. The non-rotating seal rings 6a, 6b and the mating rings 13a, which axially face the respective seal rings 6a, 6b, are fixed to the outer peripheral surface of the shaft 2 via the collars 15a, 15b, and rotate together with the shaft 2. 13b and.

More specifically, flanges 5a and 5b are formed on both inner circumferences of the holder 4 which is hermetically fixed to the inner circumference of the housing 1, and the seal rings 6a and 6b are formed on the inner circumferences of the flanges 5a and 5b. Is airtightly and axially movable. The seal ring 6a of one mechanical seal 3A has a notch 7a on its coil spring 8 side surface (hereinafter referred to as rear rear surface).
Is formed, and a retainer 9 is interposed between the rear surface and the coil spring 8 after this. The notch 7a is circumferentially engaged with a knock pin 21 for preventing rotation, which is implanted in the inner peripheral surface of the flange portion 5a of the holder 4 in the radial direction. It also serves as a stopper mechanism 20 for limiting the extension of the coil spring 8 to the left in the figure. Further, the seal ring 6b of the other mechanical seal 3b has a notch 23 formed on its outer periphery.
In the above, the drive pin 22 is axially engaged with the outer end surface of the flange portion 5b of the holder 4 in the circumferential direction, and is prevented from coming off by the head portion 22 'of the drive pin 22. That is, the seal rings 6a and 6b receive the pressing force of the coil spring 8 and the knock pin 21.
The drive pin 22 holds the holder 4 and thus the housing 1 in a non-rotating state and prevents the holder from coming off.

The rotating side mating rings 13a and 13b are arranged so that the stationary side component group including the seal ring 6a, the retainer 9, the coil spring 8 and the seal ring 6b held on the inner periphery of the holder 4 is sandwiched from both axial sides. Positioned to form sealing sliding surfaces 18a, 18b between the seal rings 6a, 6b, the bearings are carried by the collars 15a, 15b fixed to the shaft 2 by the set screws 16a, 16b, and the notches 14a are formed. , 14b
At, in the circumferential direction, the collars 15a and 15b are engaged with the rotation transmitting knock pins 17a and 17b which are axially implanted, and the rotational force from the shaft 2 is transmitted.

In the part between the two flange parts 5a, 5b in the holder 4,
A required number of openings 24 are formed, and an annular recess 25 is formed in a portion of the inner peripheral surface of the housing 1 which is in close contact with the holder 4 and which corresponds to between the material flange portions 5a and 5b. That is, the recess 25 communicates with both the mechanical seals 3A and 3B through the opening 24.

The static double mechanical seal of the above embodiment is inserted with the mechanical seal 3A inside the machine (actual liquid) side and the mechanical seal 3B outside the machine (atmosphere) side, and both mechanical seals 3A, 3B and holder 4 are installed. Lubricating oil is filled in the intermediate chamber 19 defined by the opening 24, the recess 25 of the housing 1, and the shaft 2.

Then, according to the above configuration, both mechanical seals 3A, 3B
The stationary part group of is unitized. That is, the seal rings 6a, 6b are pressed by the coil springs 8 in the direction of axially escaping from the inner periphery of the flange portions 5a, 5b of the holder 4, but the stopper mechanism including the retainer 9 and the knock pin 21 facing each other. Since it has a stopper mechanism composed of the notch 20, the notch 23 and the drive pin 22, the seal rings 6a, 6b can be extended by the coil spring 8 even if the seal ring 6a, 6b is not attached between the mating rings 13a, 13b. There is no deviation from the above, and the stationary side component group does not fall apart. Therefore, the holder 4 including the knock pin 21 and the drive pin 22, the seal rings 6a and 6b, the retainer 9, and the coil spring 8 are handled as an integrated assembly, and these are mounted between the housing 1 and the shaft 2 in a cartridge type. It can be installed at once.

Further, in the case of such a cartridge type structure, conventionally, the volume of the intermediate chamber 19 was inevitably reduced due to the presence of the holder 4 on the inner circumference of the housing 1, but according to the structure of this embodiment, Since the intermediate chamber 19 for enclosing the lubricating oil has a shape expanded to the recess 25 of the housing 1 through the opening 24 of the holder 4, the volume of the intermediate chamber 13 is increased without increasing the size of the holder 4. The lubrication effect of the hermetically sliding surfaces 18a, 18b can be enhanced.

In addition, the conventional static double mechanical seal is
In contrast to the spring type, in this embodiment, the one coil spring 8 is a one coil spring type in which the seal rings 6a and 6b are biased. by this,
Since the pitch of the coil spring 8 becomes larger than that of the multi-spring type, the coil spring 8 may be clogged by the solid content of the leaked liquid from the mechanical seal 3A on the actual liquid side, and the function may deteriorate. Moreover, it is not necessary to provide a spring holding means on the inner circumference of the holder 4.

[Effect of device]

As is apparent from the above description, according to the static double mechanical seal of the present invention, both mechanical seals are united by collectively assembling the stationary side parts of both mechanical seals into the holder. The intermediate chamber, which is filled with lubricating oil and extends to the outer circumference through the opening formed in the holder, allows the volume of the intermediate chamber to be increased without enlarging the holder, resulting in a tight seal. The lubrication effect on the sliding surface can be enhanced.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of the present invention, and FIG. 2 is a half sectional view showing a conventional example. 1 ... Housing, 2 ... Shaft, 3A, 3B ... Mechanical seal 4 ... Holder, 5a, 5b ... Flange, 6a, 6b ... Seal ring 8 ... Coil spring, 9 ... Retainer, 13a, 13b ...
… Mating ring 19 …… Intermediate chamber, 20 …… Stopper mechanism, 24 …… Opening, 25
...... Concave

Claims (1)

[Scope of utility model registration request] 1. A holder that is closely fixed to the inner circumference of a housing, two non-rotating seal rings that are fitted and inserted in the inner circumference of the holder and are aligned in the axial direction, and are externally fixed to a shaft that is inserted into the housing. The two mating rings axially contact each seal ring and extend around the outer circumference of the shaft between the seal rings.
A single coil spring that urges both seal rings in opposite directions in the axial direction and presses them against the mating rings, and a range provided in the holder so that the coil spring can extend in the axial direction is defined by the two seal rings in the holder. A housing that is provided with a stopper mechanism that limits the space between the fitting parts of the holder, and that has a required number of openings formed between the fitting parts of both seal rings in the holder and is in close contact with the holder. A static double mechanical seal, characterized in that a concave portion is formed on the inner peripheral surface of the same at a position corresponding to a fitting portion between both seal rings.