JPH02275182A - Non-contact type mechanical seal - Google Patents

Abstract

PURPOSE:To avoid the contact of seal faces with each other by forming a dynamic pressure generation group which communicates with fluid introducing grooves and extends in one circumferential direction, and a static pressure generation group which communicates with the grooves selected from the fluid introducing grooves and extends in a certain circumferential direction. CONSTITUTION:In a seal face 2a in a rotation seal ring 2A at a rotation side seal element 2, there is provided fluid introducing grooves 5 where outer ends are opened to the outside-diametrical side of a seal face 2a at particular intervals in a circumferential direction and the like, and inner ends exist in the seal face 2a and extend in an inside-diametrical direction. The grooves 5 contain the first introducing grooves 5a in approx. 5mum-1mm depth which extend from the outer ends of the seal faces 2a in a radial direction at a rate of approx. 70 to 90% to the width W1 of the seal face 2a, and the second introducing grooves 5B in approx. 5mum-1mm depth which extend from the outside the seal faces 2a in an inside-radial direction at a rate of approx. 30 to 50% to the width W of the seal faces 2a are formed alternatively in turn. A dynamic pressure generation group 6 which extends in one circumferential direction is formed in communication with each of the grooves 5A and 5B, and a static pressure generation group 7 is formed in communication with the grooves 5A.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a non-contact mechanical seal that is applied to shaft seals of high-pressure fluid equipment such as gas turbines, blowers, and near compressors.

[Prior Art J] Conventionally, for example, gas turbines, blowers and industrial machinery/builds I/1. A sealing device applied to the shaft seal of high-pressure fluid equipment such as As shown in Fig. 1, the rotating member 1 of the 4i+h 14 equipment (Fig. f:, in the example, the rotating sleeve IB that rotates simultaneously with the rotating shaft IA) and the rotary ring 2A that rotates counterclockwise are provided. Side seals 82 and spring retainers 3A fixed to the goo tongue 3 side of the device to be supported are arranged at equal intervals in the circumferential direction. Tamawari 1 (
- Through Mebin 3B 1. 4. A static pressure sealing ring which is held non-rotatably by a spring 3C and is always urged toward the rotary sealing ring 2A side. The fixed side sealing surfaces 4 are provided with A, and the sealing surface 2a of the rotary sealing ring 2A is provided with A and A in FIG.
A plurality of narrow, deep-bottomed fluid introduction grooves 5 extending in the radial direction at equal intervals in the circumferential direction are formed 12 in the -2 direction, communicating with each of these fluid introduction grooves 5, and extending in the circumferential direction ( For example, a non-contact type mechanical seal is known which has a radius 7-u extending in the direction opposite to the direction of rotational force shown by arrow a, and a dynamic pressure generating groove 6 at the bottom. When Jfi2A rotates, the fluid on the high pressure side Y flows from the fluid introduction groove 5 into the dynamic pressure generating groove 6, and dynamic pressure is generated between the sealing surface 2a and the sealing surface 4a of the stationary seal jAA. Let's make it happen, sh.
- The pressure at the balance point between the spring 3C and the spring 3C, which is biased 12 in the direction away from the seal surface 4a and in the direction lJX to bring the seal surface 4a into contact with the seal surface 2a, is applied to the seal. For example, 5-2 between surfaces 2a and 4a
The bale 4 has a narrow seal gap of about 0 gm and is configured to seal the low pressure side X and the high pressure 111Y in a non-contact state.

[Problems to be solved and attempted by the invention] By the way, the X placed on the high pressure side Y where high pressure fluid is sealed
If a high pressure is applied to the rotary sealing ring 2A with an uneven load distribution in the radial direction, the uneven distribution of the load causes 1. However, in the conventional non-contact type mechanical seal, only the dynamic pressure generating groove 6 that communicates with the fluid introduction groove 5 is provided on the sealing surface 2a of the one-turn sealing ring 2A. , the dynamic pressure generating function of the dynamic pressure generating groove 6 is reduced due to the above-mentioned distortion, and the static sealing ring 4A, which includes the force trying to open the sealing surface 2a and the spring force of the spring 3C, is The balance of the force trying to close the sealing surface 2d from the back side collapses, reducing or eliminating the gap, and as a result, the sealing surface 2a
, 4a may come into contact with each other and cause seal failure.

Moreover, even if the above-mentioned distortion does not occur in the rotating part sealing ring 2A,
In a low rotation region where the dynamic pressure is low, such as during startup or low speed rotation before stopping, the seal surface 2a, Aa times! Contact with S may cause damage to the seal. However, the rotary sealing ring 2A is not shown by the arrow a and is connected to the fluid introduction groove 5 and extends only in one direction in the circumferential direction. Rotate in the direction where the introduction groove 5 is located on the front side.
Dynamic pressure cannot be generated automatically by the dynamic pressure generating groove 6. Therefore, there is a problem in that one direction of rotation is limited to only one direction (or two).

The present invention was developed in response to these circumstances, and it is possible to reduce the dynamic pressure generation function due to distortion in the sealing ring of the rotating part, or to reduce the seal gap even if the dynamic pressure decreases in the low rotation range. The objective is to create a non-contact type mechanical seal that can be rotated in forward and reverse directions, and that can prevent damage to the seal by avoiding contact between the seal surfaces.

[Means for Solving the Problem] In order to achieve the above-mentioned object, a first aspect of the present invention provides a rotary sealing ring having outer ends opening radially outward at equal intervals on the sealing surface of the rotary sealing ring. A plurality of fluid introduction grooves are formed whose inner ends lie within the sealing surface and extend radially inward, and a dynamic pressure generating groove is formed which communicates with these fluid introduction grooves and extends in one direction in the circumferential direction. A static pressure generating groove is formed that communicates with a groove selected from the fluid introduction grooves and extends in one direction in the circumferential direction. A plurality of fluid introduction grooves are formed on the surface at equal intervals in the circumferential direction, the outer ends of which are open radially outward, and the inner ends of which are located within the sealing surface and extend radially inward. A dynamic pressure generating groove that communicates and extends in both circumferential directions is formed, and a static pressure generating groove that communicates with a fluid introduction groove other than the selected groove and extends in both circumferential directions is formed. It is.

[Operation] According to the first aspect of the present invention, due to the rotation of the rotary sealing ring, fluid enters the mover generation groove communicating with the fluid introduction groove from the radially outer side (high pressure side) to generate dynamic pressure. This dynamic pressure forms a predetermined seal gap and seals in a non-contact state.

At the same time, fluid enters the static pressure generating groove communicating with the selected fluid introduction groove to generate pocket pressure. Therefore, even if distortion occurs in the rotating sealing ring and the dynamic pressure generation function of the dynamic pressure generating groove deteriorates, resulting in a decrease in dynamic pressure, or even if the dynamic pressure decreases in the low rotation range such as during startup or before stopping, The pocket pressure generated in the static pressure generating groove acts as static pressure and can avoid contact between the seal surfaces.

Further, according to the second invention, due to the rotation of the rotary sealing ring,
Fluid enters the dynamic pressure generation groove that communicates with the selected fluid introduction groove from the radially outer side (high pressure side) to generate dynamic pressure, and this dynamic pressure forms a predetermined seal gap and seals in a non-contact state. .

At the same time, fluid enters the static pressure generating grooves communicating with grooves other than the selected fluid introducing groove to generate pocket pressure. Therefore, even if distortion occurs in the rotating sealing ring and the dynamic pressure generation function of the dynamic pressure generating groove deteriorates, resulting in a decrease in dynamic pressure, or even if the dynamic pressure decreases in the low rotation range such as during startup or before stopping, The pocket pressure generated in the static pressure generating groove acts as static pressure and can avoid contact between the seal surfaces.

Moreover, since the dynamic pressure generating groove is formed to communicate with the fluid introduction groove and extend in both circumferential directions, dynamic pressure can be generated even if the rotary seal ring is rotated in either the forward or reverse direction. can.

[Example] Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 is a longitudinal sectional side view showing the overall configuration of a non-contact mechanical seal, and FIG. 2 is a front view showing a first embodiment of a rotating a'M ring.The feature of the present invention is that the seal surface of the rotating seal ring Regarding the configuration in which both a dynamic pressure generating groove and a stationary pressure generating groove are formed, other members and configurations other than this point are the same as the conventional example, so in FIG. 2, the parts corresponding to FIG. 4 are as follows. The same reference numerals are given to each, and detailed explanation thereof will be omitted.

In FIGS. 1 and 2, the sealing surface 2a of the rotary sealing ring 2A has an outer end opening radially outward (high pressure side Y) of the sealing surface 2a at equal intervals in the circumferential direction, and an inner end opening radially outward of the sealing surface 2a (high pressure side Y). A plurality of fluid introduction grooves 5 (for example, one
2) Formed.

The fluid introduction groove 5 has a ratio of 70 to 90% (approximately 70% in the illustrated example) with respect to the surface width Wl (radial dimension) of the sealing surface 2a.
) is the depth 51 extending radially inward from the outer end of the sealing surface 2a.
The ratio of 30 to 50% (approximately 50% in the illustrated example) of the first introduction groove 5A of 1 mm Lm and the surface width W of the sealing surface 2a.
) at a depth of 5I extending radially inward from the outer end of the sealing surface 2a.
It is constructed by forming a second introduction groove 5B with a length of Lm to 1 mm for each floor. And the first introduction groove 5A
and the second introduction groove 5B and extend in one direction (counterclockwise) in the circumferential direction. 30-50% (approximately 30% in the illustrated example), depth 4-8 m
The dynamic pressure generating groove 6 set to is formed, and
The static pressure generating groove 7 communicates with the first introduction groove 5A, that is,
It extends to a position where it overlaps the terminal end of the dynamic pressure generating groove 6 adjacent to one side in the circumferential direction on the radially inner side, and the width dimension W
3 is set to 0.3 to 21111 m and the depth is set to 5 to 204 m.

With such a configuration, by rotating the rotary sealing ring 2A in the direction of the arrow a, the first
The fluid on the high pressure side Y flows from the second inflow grooves 5A and 5B into the dynamic pressure generating groove 6, generating dynamic pressure between the sealing surface 2a of the rotating sealing ring 2A and the sealing surface 4a of the stationary sealing ring 4A. The seal surface 2a is biased in the direction away from the seal surface 4a, and by the pressure at the balance point with the spring force of the spring 3C, a force of, for example, 5 to 20 g is applied between the seal surfaces 2a and 4a.
A narrow sealing gap of about m is formed to seal the low pressure side X and the high pressure side Y in a non-contact state.

At the same time, the static pressure generating groove 7 communicating with the first introduction groove 5A
Fluid also enters the area, creating pocket pressure. Therefore, distortion occurs in the rotary seal Q2A due to the above-mentioned reasons, and the dynamic pressure generating function of the dynamic pressure generating groove 6 deteriorates.
Even if the dynamic pressure decreases, or even if the dynamic pressure decreases in a low rotation range such as when the rotary sealing ring 2A is started or before stopping, the pocket pressure generated in the static pressure generating groove 7 acts as static pressure and seals. Since the surfaces 2a and 4a are prevented from coming into contact with each other, a predetermined seal gap is ensured and seal breakage is prevented.

FIG. 3 is a front view showing a second embodiment of the rotary sealing ring 2A.
The first part communicates with the introduction 5A and extends in both circumferential directions.
A static pressure generating groove 7 having the same structure as the first embodiment is formed, and a groove 7 having the same structure as the first embodiment communicates with the second introduction groove 5B having the same structure as the first embodiment and extends in both circumferential directions. It has a configuration in which a dynamic pressure generating groove 6 is formed.

With such a configuration, the rotary sealing ring 2A is aligned with the arrows a and b.
When rotating in the forward and reverse directions indicated by , the same effects as in the first embodiment can be achieved. That is, the rotation direction is -
- It is possible to provide a mechanical seal that can seal in a non-contact state even if the rotary sealing ring 2A is rotated in either forward or reverse direction without being limited only in direction.

[Effects of the Invention] Since the present invention is configured as described above, it produces the following effects.

Kn In the non-contact mechanical seal of requirement (1), due to the rotation of the rotating sealing ring, fluid enters the dynamic pressure generating groove that communicates with the fluid introduction groove from the radially outer side (high pressure side) and generates dynamic pressure. This dynamic pressure allows a predetermined sealing gap to be formed and a non-contact seal to be achieved.

At the same time, fluid enters the static pressure generating groove communicating with the selected fluid introducing groove to generate pocket pressure.

Therefore, even if distortion occurs in the rotating sealing ring and the dynamic pressure generating function of the dynamic pressure generating groove deteriorates, resulting in a decrease in dynamic pressure, or even if the dynamic pressure decreases in the low rotation range such as during startup or before stopping, The pocket pressure generated in the static pressure generating groove acts as static pressure and can avoid contact between the seal surfaces, thereby ensuring a predetermined gap and preventing seal breakage.

In addition, in the non-contact mechanical seal of claim (2), fluid enters the dynamic pressure generating groove from the radially outer side (high pressure side) which communicates with one selected fluid introduction groove by the rotation of the rotary sealing ring, causing the fluid to move. Pressure is generated, and this dynamic pressure forms a predetermined sealing gap and seals in a non-contact state.

At the same time, fluid enters static pressure generating grooves communicating with grooves other than the selected fluid introducing groove to generate pocket pressure. Therefore, even if distortion occurs in the rotating sealing ring and the dynamic pressure generating function of the dynamic pressure generating groove deteriorates, resulting in a decrease in dynamic pressure, or even if the dynamic pressure decreases in the low rotation range such as during startup or before stopping, The pocket pressure generated in the static pressure generating groove acts as static pressure, and it is possible to avoid contact between the seal surfaces. Therefore, a predetermined seal gap is secured, seal breakage can be prevented, and the direction of rotation of the rotary seal ring is not limited, so even if the rotary seal ring is rotated in either the forward or reverse direction, there is no contact. Can be sealed in any condition.

[Brief explanation of drawings]

1 to 3 show embodiments of the present invention, FIG. 1 is a vertical sectional side view showing the overall configuration, and FIG. 2 is a first embodiment of the rotary sealing ring.
FIG. 3 is an enlarged front view showing the second embodiment of the rotary sealing ring, and FIG. 4 is an enlarged front view showing the upper half of the conventional rotary sealing ring. l...Rotating member 2...Rotating side sealing element 2A...Rotating sealing ring 2a...Sealing surface 3...Casing 3C...Spring 4...Stationary side sealing element 4A...Stationary Sealing ring 5...Fluid introduction groove 5A...First introduction groove 5B...Second introduction groove 6...Dynamic pressure generation groove 7...Static pressure generation groove

Claims (2)

[Claims] (1) A rotary-side seal element equipped with a rotary sealing ring that rotates simultaneously with the rotating member of the shaft-sealed device, and a rotary-side seal element that is non-rotatably held on the casing side of the shaft-sealed device and is always attached to the rotary sealing ring side by a spring. In a mechanical seal having a stationary seal element with a stationary seal ring that is energized, the outer end opens radially outward at equal intervals in the circumferential direction on the seal surface of the rotating seal ring, and the inner end lies within the seal surface. A plurality of fluid introduction grooves extending radially inward are formed, and a dynamic pressure generating groove is formed that communicates with these fluid introduction grooves and extends in one direction in the circumferential direction. A non-contact mechanical seal characterized by forming a static pressure generating groove that communicates and extends in one direction in the circumferential direction. (2) A rotary-side seal element equipped with a rotary sealing ring that rotates simultaneously with the rotating member of the shaft-sealed device, and a rotary-side seal element that is non-rotatably held on the casing side of the shaft-sealed device and is always attached to the rotary sealing ring side by a spring. In a mechanical seal having a stationary seal element with a stationary seal ring that is energized, the outer end opens radially outward at equal intervals in the circumferential direction on the seal surface of the rotating seal ring, and the inner end lies within the seal surface. A plurality of fluid introduction grooves extending in the radial direction are formed, and a dynamic pressure generating groove is formed that communicates with a selected groove from these fluid introduction grooves and extends in both circumferential directions, and a dynamic pressure generating groove is formed that extends in both circumferential directions. A non-contact type mechanical seal characterized in that a static pressure generating groove is formed that communicates with a fluid introduction groove other than that and extends in both circumferential directions.