JPH0615169Y2 - Static mechanical seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a static mechanical seal in which a driven ring is non-rotating.

[Conventional technology]

Mechanical seals that seal the shafts of rotating equipment include static mechanical seals and rotary mechanical seals.

Among them, in the static mechanical seal, a driven ring pressed by a spring is supported by a housing on the stationary side, and a seat ring slidingly contacting the driven ring is fixed to a rotary shaft.

However, in the static mechanical seal, when the liquid to be sealed contains foreign matter, when the foreign matter accumulates in the packing interposed between the driven ring and the housing and hardens, displacement of the seat ring is prevented. The followability of the driven ring may be deteriorated and a large amount of leakage may be induced. That is, the packing interposed between the non-rotating driven ring and the housing prevents the leakage between the driven ring and the housing, and the driven ring can follow the axial displacement of the seat ring on the rotating side with good responsiveness. Therefore, the driven ring is supported so as to be movable in the axial direction. However, if the friction of the sliding portion of the packing increases due to the accumulation of foreign matter, the follow-up operation of the driven ring with respect to the axial displacement of the seat ring is delayed, and as a result, the sliding surface between the driven ring and the seat ring is delayed. Will be temporarily separated, or the contact force of the sliding surface will be excessive.

[Problems to be solved by the device]

Therefore, in order to prevent such abnormalities of the mechanical seal, it is necessary to prevent foreign matter from accumulating in the packing, but a static mechanical seal equipped with such a mechanism does not exist at present. Absent.

Therefore, the present invention has an object to prevent malfunction of a driven ring of a static mechanical seal due to accumulation of foreign matter contained in a fluid to be sealed and to prevent occurrence of a leakage accident.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the static mechanical seal of the present invention has a cylindrical driven ring supporting portion outer periphery formed by forming a non-rotating driven ring, which is pressed against a seat ring on the rotating side by a spring, in the inner diameter portion of the housing. It is fitted to a retainer that is axially movably attached to the surface via packing, and vibration generating means is built in at equal positions in the circumferential direction of the driven ring support portion. It is provided with a free-moving element disposed between them and a switching valve interlocking with the reciprocating movement of the free-moving element. This switching valve opens the air supply passage to the air ejection port on the side close to the free-moving element. On the other hand, the air supply path to the air ejection port on the side where the idler is separated is closed.

[Action]

In the above structure, the vibration generating means generates vibration by supplying air, and when the mover moves closer to one of the air ejection ports, the switching lube opens the air supply passage to the one air ejection port. In addition, since the air supply passage to the other air ejection port is closed, the mover is pushed by the ejection air from the one air ejection port and moves closer to the other air ejection port. Then, this time, the switching valve closes the air supply passage to one air ejection port and opens the air supply passage to the other air ejection port, so that the air ejected from the other air ejection port When pushed, the slider moves again toward the one air ejection port. Then, by repeating this operation, vibration is generated. This vibration
It is transmitted to the driven ring support portion of the housing and the packing interposed between the support portion and the driven ring to prevent the accumulation of foreign matter on the packing.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

First, in FIG. 1, (1) is a static mechanical seal, which is fixed to the outer peripheral surface of the shaft (7) to rotate the seat ring (2), and a non-rotating driven ring (supported on the housing (8) side ( 3) slid close to each other, so that
This prevents fluid from leaking into the atmosphere outside the machine (B). The driven ring (3) is hermetically and axially movable via an O-ring (6) as a packing on the outer peripheral surface of a cylindrical driven ring support portion (9) formed in the inner diameter of the housing (8). The seat ring (5) is fitted into the mounted retainer (4) and is mounted between the retainer (4) and the housing (8) by a plurality of coil springs (only one is shown in the figure) (5). 2) Pressed to the side.

Vibration generating means (10) driven by air is built in at equal positions in the circumferential direction of the driven ring support portion (9),
This vibration generating means (10) is provided with a working chamber (13) inside and a pair of air jets opened at positions facing each other in the working chamber (13), as shown in FIG. An air supply path (1) extending from the outside to the outlets (14a) (14b) and the respective air ejection ports (14a) (14b)
5a) and (15b) are formed on the case (12), and in the working chamber (13), a supporting plate (18) protruding from the case (12) is supported via a wire-shaped spring (17). The idler (16) that can freely reciprocate between the air outlets (14a) and (14b), and the central portion (20 ') in the longitudinal direction.
Is disposed in the valve chambers (22a) (22b) formed in each of the thin wire-shaped valve rod (20) coupled to the wire-shaped spring (17) and the air supply paths (15a) (15b). It is composed of a switching valve (19) including valve bodies (21a) and (21b) fixed to both ends of the rod (20). The switching valve (19) is shown in FIG.
When the idler (16) is on the side of the air ejection port (14a) in the working chamber (13) as shown in (1), the valve is moved by the displacement of the wire spring (17) and the valve rod (20) integral with Body (21a) is seat (23
The air supply passage (15a) is opened apart from (a) and the other valve body (21b) is in close contact with the valve seat (23b) and the other air supply passage
(15b) is closed, and conversely, the mover (16) is shown in Fig. 2 [b].
When it is on the air ejection port (14b) side, the valve body (21a) closes the air supply path (15a) and the other valve body (21b)
Opens the other air supply passage (15b). Reference numeral (11) is a pipe line passing through the driven ring support portion (9), one end of which is connected to an external air supply source and the other end of which is branched to supply air in the case (12) of the vibration generating means (10). It communicates with the roads (15a) (15b). The valve rod (20) may be thread-shaped or string-shaped.

In the above embodiment, in the vibration generating means (10), the idler (16) initially has the working chamber (13) as shown in FIG.
It is assumed that there is uneven distribution on the side of the air ejection port (14b). In this case, since the switching valve (19) closes the air supply path (15a) and opens the air supply path (15b), when air is supplied from the air supply source through the pipe line (11), This air is ejected from the air ejection port (14b) through the air supply passage (15b) and pushes out the mover (16). By this
When the air ejecting port (14a) on the opposite side is moved toward the opposite side so that (16) is repelled, as shown in FIG.
With the valve rod (20) interlocking with the wire-shaped spring (17) of the switching valve (19), the valve body (21a) of the switching valve (19) opens the air supply path (15a), and conversely the valve body (21b) is opened so far. The air supply path (15b)
The air flow path from the conduit (11) is switched from the air supply path (15b) to (15a) in order to close the valve. Therefore, the air outlet
The idler (16) reaching the (14a) side is pushed out so as to be repelled by the air jetted from the air jet port (14a), and the state shown in FIG. This series of operations is automatically repeated unless the air supply is stopped, and the thrust (reaction) of the air that alternately ejects from the air ejection ports (14a) and (14b) operates the idler (16). , Vibration generating means (10)
A slight vibration is caused. The air outlet (14a) (14
The air ejected from b) into the working chamber (13) is discharged from the mechanical seal inner peripheral space (B ') to the outside of the machine (B) through the exhaust hole (24). In addition, this air is the space (B ')
Seat ring (2) and driven ring (3) as they are ejected from
Removes frictional heat generated on the sealed sliding surface of the
Foreign substances and the like that have entered the space (B ′) from the side are discharged together.

The vibration from the vibration generating means (10) is generated by the driven ring support (9).
Is transmitted to the O-ring (6) that seals between the driven ring support portion (9) and the retainer (4) of the driven ring (3),
It makes it difficult to deposit foreign matter on the O-ring (6). Also, O
The vibration transmitted to the ring (6) is attenuated by viscoelasticity of the elastomer forming the O-ring (6), and a part of this vibration is also transmitted from the retainer (4) to the coil spring (5), It also acts to prevent the accumulation of foreign matter on the coil spring (5). Further, if the amplitude from the vibration generating means (10) is too large, the O-ring (6), the driven ring support part (9) and the retainer are retained.
(4) There is a risk of adversely affecting the sealing performance between
The amplitude is set within an appropriate range depending on the pressure of the supply air, the spring constant of the wire spring (17), the mass and stroke of the idler (16), and the like.

The present invention is not limited to the embodiment shown in the drawings. For example, the vibration generating means has only one air supply passage, one air ejection port and one valve body, and the vibration element is attached to the air ejection port. It is possible to have a vigorous configuration or make various changes.

[Effect of device]

As described above, according to the present invention, the vibration generating means built in the driven ring support portion of the housing gives a slight vibration to the packing interposed between the driven ring support portion and the non-rotating driven ring, and the packing is inserted into the packing. Since it is possible to prevent the malfunction of the driven ring due to the accumulation of foreign matter, it is possible to prevent a leakage accident due to the malfunction, and the air that drives the vibration generating means removes the heat generated on the sliding surface. At the same time, it has an excellent effect of removing foreign matter that has entered from the atmosphere side.

[Brief description of drawings]

FIG. 1 is a schematic half sectional view showing an embodiment of the present invention, and FIGS. 2A and 2B are enlarged sectional views showing the operation of the vibration generating means. (1) …… static mechanical seal (2) …… seat ring, (3) …… driven ring (4) …… retainer, (5) …… coil spring (6) …… O-ring (packing), (7 ) …… Shaft (8) …… Housing, (9) …… Driven ring support (10) …… Vibration generator, (14a) (14b) …… Air jets (15a) (15b) …… Air supply Road, (16) …… Midler (19) …… Switching valve

Claims (1)

[Scope of utility model registration request] 1. A non-rotating driven ring, which is pressed against a seat ring on the rotating side by a spring, is axially movable via packing on an outer peripheral surface of a cylindrical driven ring supporting portion formed in an inner diameter portion of a housing. Fit into the attached retainer,
The vibration generating means is built in the circumferentially equidistant positions of the driven ring support portion, and the vibration generating means is provided for the reciprocating movement of the idler arranged between the pair of air ejection ports. An interlocking switching valve is provided, and this switching valve opens the air supply path to the air ejection port on the side close to the idler, while closing the air supply path to the air ejection port on the side away from the idler. A static mechanical seal that is characterized by being