JPH0614151Y2 - Dry sliding mechanical seal - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is a mechanical seal for sealing the circumference of a rotary shaft of equipment, and is used especially under the condition that gas is sealed and the sliding surface is not liquid-lubricated. It relates to the improvement of mechanical seals.

[Conventional technology]

Conventionally, as shown in FIGS. 2 and 3, a non-rotating sliding ring 5 is hermetically fitted to the inner circumference of a housing 51.
2 and a sliding ring 54 that is hermetically attached to the outer periphery of the shaft 53 in a circumferentially engaged state and rotates.
There is widely known a mechanical seal that seals and slides with each other by an axial load from the shaft to seal the shaft.

In such a mechanical seal, when a liquid is to be sealed, the sliding surfaces 5 of both sliding rings 52, 54
It is lubricated by the liquid film between 2'and 54 ',
Moreover, although sliding heat is removed, when a gas is to be sealed, the sliding surfaces 52 'and 54' slide under dry conditions without liquid lubrication, and the lubrication constitutes both sliding rings 52 and 54. Since it depends only on the self-lubricating property of the sliding material,
Of the sliding rings 52 and 54 having different hardness, a soft sliding material, for example, Teflon (trade name) material having excellent self-lubricating property is used to reduce the sliding resistance.

[Problems to be solved by the invention]

However, in the dry-sliding mechanical seal as described above, the abrasion powder generated by the abrasion over time due to the sliding of the sliding surfaces 52 ', 54' is caught between the sliding surfaces 52 ', 54'. In rare cases, it may cause surface roughening, wear, and abnormal heat generation.

The present invention has been made in view of such a point, and an object thereof is to forcibly eliminate the abrasion powder between the sliding surfaces to eliminate problems such as surface roughness.

[Means for solving problems]

In order to solve the above-mentioned problems, the dry sliding mechanical seal according to the present invention has a plurality of blades made of an elastic body on the outer periphery of an annular sliding surface protruding from a sliding ring on the soft side. It is configured so as to be inclined in the opposite direction and provided in a circumferentially even distribution.

[Action]

According to the structure of the present invention, the blades on the outer periphery of the sliding surface act like a kind of impeller during operation, that is, the blades and the gas around them actuate relatively in the circumferential direction,
A pressure gradient that causes a low pressure on the outer peripheral side between the sliding surfaces,
The abrasion powder generated between the sliding surfaces is sucked and discharged to the outer circumference of the sliding surface.

Further, since this blade is made of an elastic material, it falls toward the side opposite to the rotating direction due to the sliding resistance with the mating sliding surface at the time of rotation, and the higher the speed, the greater the inclination. The increase in the resistance to and is alleviated, and the generation of an excessive pressure gradient that causes leakage between the sliding surfaces is also prevented.

〔Example〕

The present invention will be described below with reference to an embodiment shown in FIG.

Reference numeral 1 denotes a soft side sliding ring of a pair of sliding rings having different hardness which constitutes a mechanical seal, and is formed of a Teflon (trade name) material, and is airtight via a packing on the outer circumference of a shaft (not shown). Is mounted on the shaft and rotates in the direction of arrow A together with the shaft.

An annular sliding surface 2 that is in sliding contact with a non-rotating mating sliding ring is provided on one end of the sliding ring 1 in the axial direction.
On the outer peripheral edge of the sliding surface 2, a plurality of blades 3 made of an elastic body having an appropriate inclination angle with respect to the circumferential surface so as to have a large diameter in the counter-rotational direction (direction opposite to the arrow A). 3 ... are fixed in an evenly distributed manner in the circumferential direction.

When the sliding ring 1 rotates in the direction of the arrow A, the blades 3 which rotate in association with the sliding ring 1 act as a kind of impeller, that is, the gas in contact with the blades 3 is pushed away to the outer peripheral side, whereby the blades 3 move. The anti-rotation side space becomes negative pressure, and the negative pressure causes the abrasion powder generated between the sliding surface 2 and the mating sliding surface facing the sliding surface 2 to be sucked and discharged to the outer peripheral side.

Here, since the blade 3 is made of an elastic thin plate, as shown by the broken line in the figure, the blade 3 falls toward the side opposite to the rotation direction A due to the sliding resistance with the mating sliding surface during rotation, and the higher the speed, the more the inside. Since the inclination angle with respect to the peripheral surface becomes small, the increase in the sliding resistance and the increase in the resistance with the surrounding gas due to the increase in the rotational speed are alleviated, and therefore, the radial direction between the sliding surface and the mating sliding surface is reduced. Excessive pressure gradients and increased leakage are also prevented.

[Effect of device]

As described above, according to the present invention, the elastic blades provided on the outer periphery of the sliding surface act like an impeller by rotation,
Wear powder generated by sliding of both sliding rings is forcibly discharged to the outer space of the seal, eliminating problems such as surface roughness and wear of the sliding surface due to biting of wear powder and abnormal heat generation. Further, it is possible to achieve an excellent effect that the provision of the vanes can suppress an increase in resistance during high-speed rotation and the generation of excessive pumping pressure that causes leakage.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part showing an embodiment of a dry sliding mechanical seal according to the present invention, FIG. 2 is a half-cut sectional view showing a conventional example, and FIG. 3 is a front view of the sliding ring. . 1 ... Soft side sliding ring, 2 ... Sliding surface 3 ... Blade

Claims (1)

[Scope of utility model registration request] 1. A non-rotating sliding ring, which has different hardness and is hermetically supported on the housing side, and a sliding ring, which is hermetically supported and rotating on the shaft side, are in close contact with each other in a dry atmosphere. In a dry sliding mechanical seal, a plurality of blades made of an elastic body are tilted in the direction opposite to the rotating direction on the outer circumference of an annular sliding surface protruding from the sliding ring on the soft side, and are equally distributed in the circumferential direction. Dry sliding mechanical seal characterized by being provided in the shape of a ring.