JP2838012B2 - Mechanical seal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic method in which a sealed fluid is used between planar sealed end faces, one of which is stationary and the other of which is rotating and interacting with each other. The present invention relates to a mechanical seal device for a rotating shaft that generates a (hydrostatic) -hydrodynamic force or an aerostatic-aerodynamic force. The above force provides a small gap between the sealed end faces and provides a non-contact effect, thereby reducing energy loss due to wear and friction of the sealed end faces and keeping fluid leakage low. .

[0002]

2. Description of the Related Art Rotary fluid film face seals, also called non-contact face seals, are generally applied to high speed, high pressure rotating equipment. This is because, in such a high-speed and high-pressure rotating device, using a mechanical face seal with normal face contact causes excessive heat and wear. This undesired surface contact is avoided because non-contact effects occur when the shaft is rotating beyond a certain minimum speed.
There are various ways to achieve the above non-contact action, of which the most successful is to apply a pattern of shallow spiral grooves to one of the sealing edges. The sealing end face opposed to the sealing end face provided with the groove is relatively flat and smooth. The sealing area where these two sealing edges define the sealing gap is called the sealing interface.

[0003] The spiral groove provided on one of the above-mentioned sealed end faces usually extends inward from the outer peripheral edge, and ends at a position of a specific diameter called a groove diameter. It is important that the spiral groove pattern terminates at a groove diameter that is greater than the inner diameter of the sealing area. The non-grooved area between the groove diameter and the inner diameter of the sealed area serves as a deterrent to fluid leakage. Fluid carried from the spiral groove pattern passes through this stop only when the pair of sealed end faces is opened, and this is done by increasing the pressure. When the sealed end face is kept in contact,
The fluid is compressed just before the restraint and the pressure rises. This pressure generates a separating force, which eventually exceeds the force of maintaining the contact between the two sealed ends. At that point, the two sealed end faces in a sealed state separate, allowing fluid leakage. During the sealing operation, a balance is established between the inflow of fluid by the pump action of the spiral groove and the leakage by separation of the sealing end face. Therefore, the separation of the sealed end faces exists as long as the sealing operation is performed, that is, as long as one sealed end face is rotated with respect to the opposing sealed end face. However, the pumping action of the spiral groove is not the only factor that determines the degree of separation between the sealing end faces. Just as a spiral groove can pump fluid beyond the groove diameter into an ungrooved area of the sealed area, the pressure differential also exerts such an effect. If there is a sufficient pressure difference between the end of the groove in the sealed area and the end of the grooveless part, the fluid is also forced from the groove into the grooveless part of the sealed area, thereby separating the opposing surfaces. , A gap is formed.

[0004] Two cases in which a gap can be formed between the sealing end faces, one due to the rotational speed and the other due to the pressure difference, they have two effects during the sealing operation. Although appearing in combination, they are distinct from each other. If there is no pressure difference and the separation between the sealing edges only occurs by strict rotation, the force due to the fluid is known as hydrodynamic force if the sealing fluid is a liquid, and if the sealing fluid is a gas. If there is, it is known as aerodynamic (aerodynamic) force.

On the other hand, if there is no relative rotation between the two sealing ends, the separation of the sealing ends is strictly between the two ends between the ends of the grooves and the ends of the grooves in the sealing area. The force of the fluid,
If the sealing fluid is a liquid, it is called hydrostatic force, and if the sealing fluid is a gas, it is called hydrostatic force. In the following, the terms hydrostatic and hydrodynamic shall be used for both liquids and gases,
The terms hydrostatic and hydrokinetic are used.

What is required of a fluid seal using a spiral groove is that it perform satisfactorily with respect to leakage and that there is no contact between the sealing end faces during the entire operation of the sealing operation. This must be achieved not only at the highest rotational speeds and pressures, but also at rest, during start-up, during acceleration, during the running-in period of the device and during the shutdown period of the device. In normal operating conditions, the pressure and the speed of rotation change at a constant rate, so that the sealing end gap during operation is constantly adjusted. These adjustments are made automatically. That is, an important property of the fluid seals by the spiral grooves is their ability to self-adjust, and with changes in rotational speed or pressure, the face clearance is automatically adjusted to accommodate new conditions. This adjustment is made by hydrostatic and hydrodynamic forces.

[0007] The range of operating conditions with respect to rotational speed and pressure is usually very wide, and fluid-tight designs necessarily require compromises. The permissible performance when the rotational speed or the pressure is close to zero is lower than the optimal condition of the rotational speed and the pressure in the normal operation. This means that, in terms of both rotation and pressure, the fluid seal must be covered from zero speed and pressure differential to operation. A particular problem in the operation of the fluid seal is at the start of operation. In the case of fluid sealing in a centrifugal gas compressor, the total pressure difference of the gas suction is often applied to the sealing mechanism as it is before the rotation of the shaft starts. This creates the risk that the opposing sealing end faces are locked together due to friction. This locking of the sealing face occurs when the hydrostatic forces cannot sufficiently oppose the pressure of bringing the opposing sealing face into contact. Locking of the sealed end face can lead to disruption of the fluid seal, in which case the contacted seal end face can cause severe wear or leakage of the internal sealing fluid.

Therefore, first, the spiral groove is required to be able to hydrodynamically separate the sealed end faces in order to guarantee full speed non-contact operation. This usually requires a relatively short and relatively deep spiral groove. Next, the spiral groove is required to be capable of hydrostatically releasing the load on the sealed end face so that the sealed end face is not locked at the start and stop of operation. For this purpose, the spiral groove must extend long. However, the elongated spiral groove promotes separation of the sealing end face and consequent leakage during full speed operation.

Prior art leading to the current spiral groove design is disclosed in US Pat.
It goes back to No. 58. The technique is that two opposing spiral grooves supply oil to each other, thereby creating a liquid barrier that can seal gas. However, in such a configuration, since the power of the liquid is used for sealing the gas, the rotation speed and the pressure are limited. The second important prior art is U.S. Pat.
653. Garner adopts the structure of the sealed end face with a partial spiral groove, which is currently widely used, while increasing the width of the spiral groove to the non-groove end side in anticipation of the hydrostatic effect. It has a tapered shape that narrows toward it. However, in this case, the hydrodynamic force is reduced since the pumping action over the wide groove is reduced. This affects the stability of the seal and also limits the maximum pressure and rotational speed.
The next major prior art is U.S. Pat. No. 4,212,475 to Cedi. This technique requires that the width of the groove be tapered, taking advantage of the fact that the spiral groove itself acts not only as a hydrodynamically effective pattern but also as a hydrostatically effective pattern. Which allows a significant portion of the hydrodynamic forces of the spiral groove to be used to impart self-alignment to the sealing end face. This self-alignment property returns the sealing end face to a parallel position even if the parallelism of the sealing end face shifts radially or tangentially during operation, thereby improving the stability of the sealing action entirely. And the restrictions on pressure and rotational speed can be greatly improved.

[0010]

However, in the conventional mechanical seal device using a spiral groove described above, the pressure and the rotational speed are still limited, that is, the sealing effect at the time of starting or stopping the operation. It was insufficient to stably satisfy both the sealing function during high-speed operation.

Therefore, the present invention solves the above-mentioned drawbacks of the conventional mechanical seal device, and can further increase the applicable range of the pressure and the rotational speed in the conventional mechanical seal device using the spiral groove and use the spiral groove. A mechanical seal device that can improve the sealing performance, reliably prevent the sealing of the sealing area and sealing end face and the leakage of the fluid to be sealed under a wider range of operating conditions, and perform high-speed, high-pressure operation in a stable sealed state. The purpose is to provide.

[0012]

In order to achieve the above object, a mechanical seal device according to the present invention comprises a housing 10;
The first shaft is attached to the rotating shaft 12 to seal the fluid to be sealed between the rotating shaft 12 and the first shaft.
A first seal ring 20 having a sealed end face 21 and a first seal ring 2 on the housing 10 side.
A second sealing ring 18 having a flat second sealing end face 19 disposed coaxially with the first sealing end face 21 and disposed axially opposite to and adjacent to the first sealing end face 21; 1
One of the seal ring 20 and the second seal ring 18 is movable in the axial direction, and the movable seal ring is urged toward the other seal ring by the elasticity applying means 30. First and second facing
A mechanical sealing device in which an annular sealing area is formed between the outer peripheral edge and the inner peripheral edge of the sealing end faces 21, 19 by the first and second sealing end faces 21, 19. 19, a plurality of first grooves 22 spirally extending inward from the outer peripheral edge on the side in contact with the sealed fluid and formed at intervals in the circumferential direction. When the same first and provided a plurality of second grooves 24 and 25 formed in plural on the seal end faces 21, and the first groove 22 and second groove 24 and 25, wherein the sealed
The first groove 22 starts from the outer peripheral edge in contact with the fluid .
Then , the second grooves 24 and 25 are connected to the ends thereof and started, and further extended inward without reaching the inner peripheral edge, so that the sealed fluid contacts the outer peripheral edge inward. The first groove 22 and the second grooves 24 and 25 are connected via a step 26, and the first groove 22 is fluidized by the step 26. A first feature is that the grooves are deep enough to form a dynamic fluid bearing and the second grooves 24, 25 are shallow enough to form a hydrostatic hydrodynamic bearing. And Further, in addition to the first feature, the mechanical seal device of the present invention has a depth of the first groove 22 of 0.02.
The second feature is that it does not exceed 54 mm. Further, the mechanical seal device of the present invention may be arranged such that the first or the second
In addition to the features described above, the depth of the first groove 22 is 0.0025.
A third feature is that the range is 4 mm to 0.00762 mm. In addition, the mechanical seal device of the present invention may be arranged such that, in addition to any one of the first to third features, the depth of the second grooves 24 and 25 is 0.000254 mm to 0.000025 mm.
The fourth feature is that the range is 1778 mm. In addition, the mechanical seal device of the present invention includes
In addition to any one of the features of the fourth aspect, the fifth feature is that the depth ratio between the second grooves 24 and 25 and the first groove 22 is in the range of 0.05 to 0.25. Further, in the mechanical seal device of the present invention, in addition to any one of the above-described first to fifth features, the second groove 24 is spirally extended inward continuously from the first groove 22. This is the sixth feature. In addition, the mechanical seal device of the present invention is characterized in that the first
In addition to any of the above-mentioned features, the seventh feature is that the second groove 25 extends in the radial direction toward the inner peripheral edge. An eighth feature of the mechanical seal device of the present invention is that, in addition to any one of the first to seventh features, each of the first groove 22 and the second grooves 24 and 25 has a constant depth. And Further, in addition to the features of any one of the first to seventh aspects, at least one of the first groove 22 and the second grooves 24 and 25 has a depth inward from the outer peripheral edge side. A ninth feature is that the taper shape is such that it gradually becomes shallower.

[0013]

According to the first feature of the present invention, the first groove 2 is provided.
Combining the second and second grooves 24 and 25 as one groove pattern prevents disadvantages such as an excessive gap due to an excessive hydrodynamic effect and an increase in leakage of a sealed fluid, thereby ensuring safety. It is possible to obtain a hydrostatic opening force of the sealed end face for a proper start and stop of operation. The first groove 22 having a large depth is expected to have a hydrodynamic action, and when the shaft 12 rotates, the sealing fluid is sealed to the sealing end face 2.
Pumping between 1 and 19 provides a suitable small gap between the sealing faces 21 and 19 to prevent contact, locking, wear, etc. between the sealing faces 21 and 19. Further, the second grooves 24 and 25 having a small depth are expected to have a hydrostatic action, and when the shaft 12 stops rotating or is in a state close to stopping, the gap between the sealed end faces 21 and 19 is reduced. By supplying the fluid to be sealed, the contact, lock, wear, etc. between the sealed end faces 21 and 19 when rotation of the shaft 12 is started or stopped is prevented, and the contact pressure between the sealed end faces 21 and 19 is minimized. This is useful for sufficiently reducing the torque at the time of starting or the like. As described above, according to the first aspect of the present invention, the deep first groove 22 and the shallow second groove 2 formed of a spiral groove are provided.
The combination with 4, 25 improves the sealing effect under both conditions at the start and stop of the operation and at the time of steady operation (at full speed rotation), which was not sufficient with a single conventional spiral groove, and stopped the operation. In addition, in a wide range from low speed to high speed, it is possible to prevent the sealing end face from being locked and prevent a large amount of leakage of the fluid to be sealed, thereby obtaining a stable fluid sealing performance. In particular, in the first feature, by adopting a configuration in which the shallow second grooves 24 and 25 are connected to the end of the deep first groove 22, two different types of grooves, that is, the first groove 22 Since the second grooves 24 and 25 are formed as one single pattern extending inward from the outer peripheral edge, the structure becomes very simple in structure, and a plurality of different types of grooves are formed in the circumferential direction. In comparison with a multi-patterned pattern, it is very easy to form or form a groove in the sealed end face, and the defect rate can be reduced accordingly. In addition, in the first feature, different types of first
The groove 22 and the second grooves 24 and 25 are formed as one single pattern inward from the outer peripheral edge, so that a plurality of different types of grooves are gathered in the circumferential direction. Compared to the multiple pattern, a larger number of groove patterns can be formed in the circumferential direction of the sealing end face, and the uniformity in the circumferential direction can be improved. The first groove 22 and the second groove
Grooves 24 and 25 are different types depending on the depth of the grooves, so that it is not necessary to use a wide-width groove in order to make the type of the groove different depending on the groove width. The occupied area of the pattern can be reduced, so that a large number of groove patterns can be formed in the circumferential direction, and the uniformity in the circumferential direction can be improved as described above. In addition the first aspect, since the end of the deep first groove 22 extending from the outer periphery inwardly is connected to the second grooves 24 and 25 via a step portion 26, during pre-rotation Kidan unit 26 serves as a kind of dam and sufficiently suppresses the sealing fluid from going from the deep first groove 22 to the shallow second grooves 24 and 25, and as a result, the inside of the deep first groove 22 is sufficiently filled. , An effective hydrodynamic pressure can be efficiently generated. The first groove 2 by the front Kidan section 26
2 is divided into grooves of sufficient depth to form a hydrodynamic fluid bearing, and the second grooves 24, 25 are divided into shallow grooves sufficient to form a hydrostatic hydrodynamic bearing. As a result, the sufficiently deep first groove 22 can provide a sufficient hydrodynamic sealing action at high speed rotation, and the sufficiently shallow second grooves 24 and 25 can be used to stop or start operation. Effective hydrostatic sealing of the two
And 24, 25) without adversely affecting each other. According to the second feature, in addition to the operation of the first feature, the depth of the first groove 22 is
0. 0254mm
The hydrodynamic sealing effect of the groove 22 can be performed without significant side effects. According to the third feature, in addition to the action of the first or second feature, the first groove 2
2 in the range of 0.00254 mm to 0.00762 mm so that the sealing end face 2 can be rotated at full speed.
The gap between the sealing end face 2 and the gap in a range that can sufficiently prevent the lock, high friction, and abrasion between the first and the 19th to ensure the stable high-speed rotation and sufficiently prevent the leakage of the sealed fluid can be obtained.
1. The hydrodynamic pressure that can be reliably introduced between 19 and
It can be generated in the first groove 22. According to the fourth feature, in addition to the operation according to any one of the first to third features, the depth of the second grooves 24 and 25 is set to 0.00025.
By setting the thickness in the range of 4 mm to 0.001778 mm, locking, high friction and wear between the sealing end faces 21 and 19 are sufficiently prevented during operation stop and low speed rotation at the start and stop of operation, and the sealed fluid Hydrodynamic pressure can be generated in the second grooves 24 and 25 so as to reliably introduce a gap between the sealing end faces 21 and 19 in a range where leakage can be sufficiently suppressed. According to the fifth feature, in addition to the action of any of the first to fourth features, the second feature
The depth ratio of the grooves 24, 25 to the first grooves 22 is 0.05
By setting the range to .about.0.25, the second grooves 24 and 25 are sufficiently shallower than the first groove 22 and the first groove 22 is
Can be formed sufficiently deeper than and deeper than the grooves 24 and 25 of the first groove 22, whereby the hydrodynamic action of the relatively deeper first groove 22 and the relative The hydrostatic action of the shallow second grooves 24 and 25 can be performed sufficiently effectively without adversely affecting each other. In addition, the first groove 22
Grooves 24, 25 connected to the ends of
Is located at the end of the first groove 22 as in the sixth feature.
The groove 24 may be spirally extended, or the second groove 25 may be radially extended toward the inner peripheral edge at the end of the first groove 22 as in the seventh feature. . When the second groove is provided in a spiral shape, very smooth continuation with the first groove 22 is made. In addition, the first groove 22 and the second groove 2
The 4, 25, as in the eighth feature, the their respective
The depth may be constant, and as in the ninth feature, the depth of one or both of the first groove 22 and the second grooves 24 and 25 is gradually increased inward from the outer peripheral edge. It may be tapered so as to be shallow.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial cross-sectional view showing the configuration in the longitudinal direction of a mechanical seal device manufactured according to the present invention, and shows the relative positions of various parts when the shaft rotates.
2 is a sectional view taken along line 2-2 of FIG. 1, and FIG.
It is three sectional drawing. FIG. 4 is a view showing a comparative example, and is a schematic side view showing a sealed region, a seal ring, and an axial force acting thereon. FIG. 5 is a pressure-gap diagram showing the hydrostatically generated gap and the hydrodynamically generated gap for four different spiral groove patterns. FIG. 6 is an enlarged view showing an example of two contacting flat surfaces. FIG. 7 is a diagram showing another embodiment similar to FIG. FIG. 8 is a diagram showing another embodiment similar to FIG. FIG. 9 is a diagram showing still another embodiment similar to FIG.

First, a first embodiment of a mechanical seal device according to the present invention will be described with reference to FIGS. FIG. 1 shows the part of the present invention and its attached parts. The attachment includes a housing 10 and a rotating shaft 12 extending through the housing 10. The present invention is applied to seal a sealed fluid made of a liquid inside the annular space 14 and prevent the sealed fluid from leaking to the surrounding environment 16. The basic component of the invention comprises an axially movable annular second sealing ring 18, which has a flat second sealing end face 19 extended in the radial direction, With the second sealing end face 19 and the radially extended flat first sealing end face 21 of the rotatable annular first sealing ring 20, between which the annular shape from the outer peripheral edge to the inner peripheral edge Of the sealed region.
The second seal ring 18 is located in the cavity 15 of the housing 10 and is provided with the rotatable first seal ring 2.
0 and are held to the same core. A plurality of springs 30 are provided as elasticity applying means between the housing 10 and the second seal ring 18 movable in the axial direction, and the plurality of springs 30 are arranged at equal intervals around the cavity 15 of the housing 10. Have been. Spring 30 biases second seal ring 18 into contact with first seal ring 20. O-ring 38 seals between second seal ring 18 and housing 10. First
The seal ring 20 is held at a fixed position in the axial direction by a sleeve 32. The sleeve 32 is coaxially fixed to the shaft 12 with a lock nut 34. The lock nut 34 is screwed onto the shaft 12. O-ring seal 36 prevents leakage between first seal ring 20 and shaft 12.

The first sealing end face 21 and the second sealing end face 19 form a very narrow gap as a sealing area in order to perform the sealing action of the fluid to be sealed. The very narrow gap is formed by two types of grooves 22, 24 formed in the first sealed end face 21 selected as one of the first sealed end face 21 and the second sealed end face 19,
That is, it is provided by the combination of the first groove 22 and the second groove 24. The first groove 22 is formed to extend spirally inward from the outer peripheral edge on the side in contact with the sealed fluid, and a plurality of the first grooves 22 are formed at regular intervals in the circumferential direction. . The second groove 24 is also a spiral groove in this embodiment. The first groove 22 and the second groove 24 start when the second groove 24 is connected to the end of the first groove 22 and the second groove 24 extends further inward therefrom. It is provided and configured. Thereby, two different types of grooves, the first groove 22 and the second groove 24, are configured as one single pattern. The end of the second groove 24 also forms a step 28 and does not reach the inner peripheral edge, but rather ends in the middle. Thus, the second groove 24 is located near the center between the outer peripheral edge and the inner peripheral edge. Each step 26 and each step 28 constitute a part of the concentric circumference. End of the first groove 22 is formed as a stepped <br/> unit 26, the second groove 24 through the stepped portion 26 of this is being connected. The front Kidan unit 26, the first groove 22 is sufficiently deep groove to form a hydrodynamic fluid bearing, although the second groove 24 to form a hydrostatic fluid bearing It is a sufficiently shallow groove. In this embodiment, as shown in FIG.
Each of the bases 4 has a constant depth at the bottom , that is, each is flat. In this embodiment, the first groove 22 and the second groove
The groove 24 is formed as a spiral groove so that the groove 24 is continuous with a very smooth curve. The first and second grooves 22 and 24 formed in the spiral are counterclockwise and inward with respect to a specific rotation direction of the shaft 12, and the rotation of the shaft 12 is opposite to the above. Clockwise and inward with respect to the direction. The first groove 22 and the second groove 24 can be patterned on the first sealing end face 21 of the first seal ring 20 by chemical etching. The pattern of the first groove 22 and the second groove 24 may be applied to the second sealing end face 19 of the second seal ring 18.

The deeply formed first groove 22 provides hydrodynamic pressure during rotation, thereby introducing a small gap between the sealing end faces 21, 19, forming a fluid bearing and Maintain the seal of the sealed fluid.
That is, during rotation, the sealing fluid flows into the first groove 22 from the outer peripheral edge that is in contact with the sealed fluid side, so that hydrodynamic pressure is generated in the first groove 22. Arises
When this pressure exceeds the pressure for closing the sealing end faces 21 and 19, a fluid gap is introduced between the sealing end faces 21 and 19. Where the two pressures are balanced, the size of the gap is determined. The gap introduced by the hydrodynamic pressure by the first groove 22 constitutes a fluid bearing, and locks between the sealing end faces 21 and 19, large friction,
Wear will be prevented, while the gap will be large.
The greater the leakage, the greater the leakage of the sealed fluid. Therefore, the size of the gap requires a minimum size that does not cause a lock or a large friction between the sealing end faces 21 and 19, and the gap should not be too large. For this reason, the depth of the first groove 22, which provides a hydrodynamic pressure that creates a gap between the sealing end faces 21, 19, is problematic. The depth of the first groove 22 is 0.00254 mm.
(0.0001 inch) to 0.00762 mm (0.0
003 inches). In this range, the first groove 2
With a depth of 2, the lock, high friction and wear between the sealing end faces 21 and 19 are sufficiently prevented at full-speed rotation to ensure stable high-speed rotation and sufficient leakage of sealed fluid. The gap that can be suppressed to the sealed end
It can be reliably introduced between the surfaces 21 and 19. Also,
The depth of the first groove 22 should not exceed 0.0254 mm (0.001 inch). If the first groove 22 has a depth exceeding 0.0254 mm, various adverse effects occur.

The shallow second groove 24 provides hydrostatic pressure during rotation stop, rotation start, and low rotation at the time of rotation stop, and thereby, between the sealing end faces 21 and 19. A small gap is introduced to form the fluid bearing and to keep the sealed fluid tight. That is,
When the rotation is stopped or at the time of low rotation at the start and stop of the operation, hydrostatic pressure is generated by the sealed fluid existing in the second groove 24 following the outer peripheral edge in contact with the sealed fluid side. When the pressure exceeds the pressure for closing the gap between the sealing end faces 21 and 19, a fluid gap is introduced between the sealing end faces 21 and 19. Where the two pressures are balanced, the size of the gap is determined. The second groove 24
The gap introduced by the hydrostatic pressure by the fluid constitutes a fluid bearing, and prevents locking, large friction and wear between the sealing end faces 21 and 19, particularly when the rotation is started or when the rotation is not stopped. On the other hand, the larger the gap, the greater the leakage of the sealed fluid. Therefore, the size of the gap requires a minimum size that does not cause a lock or a large friction between the sealing end faces 21 and 19, and the gap should not be too large. For this reason, the depth of the second groove 24 which provides a hydrostatic pressure that causes a gap between the sealing end faces 21 and 19 is also an issue. The depth of the second groove 24 is 0.0002
54mm (0.00001 inch)-0.001778
mm (0.00007 inch) is most desirable. By configuring the depth of the second groove 24 in this range, at the time of rotation stop, at the time of startup, or at the time of low rotation at which rotation is not stopped,
It is possible to reliably introduce a gap between the sealed end faces 21 and 19 within a range capable of sufficiently preventing locking, high friction and wear between the sealed end faces 21 and 19 and sufficiently suppressing leakage of a sealed fluid. it can. Further, the ratio of the depth of the second groove 24 to the depth of the first groove 22 is preferably in the range of 0.05 to 0.25. By setting the depth ratio in this range,
The first groove 22 allows a suitable gap to be introduced hydrodynamically between the sealing end faces 21, 19 and the second groove 24
This allows a suitable gap to be introduced hydrostatically between the sealing end faces 21, 19. In addition, the step 26 between the first groove 22 and the second groove 24 can be made sufficiently large, so that the adverse effect of the second groove 24 when the hydrodynamic action by the first groove 22 is performed is reduced. Lost, second
The adverse effect of the first groove 22 when the hydrostatic action by the groove 24 is performed can be eliminated. still,
In the example shown in FIG. 2, the second groove 24 is a spiral groove like the first groove 22, but is not limited to the spiral groove. The second groove 24 may be any that extends inward from the step 26 at the end of the first groove 22. In the example shown in FIG. 7, the second groove 25 is configured to start from the step portion 26 which is the end of the first groove 22 and to extend radially toward the inner peripheral edge. Also, the second groove 25 is also terminated at the intermediate position before reaching the inner peripheral edge and is formed of the step portion 28, so that the second groove 25 is also located near the center between the outer peripheral edge and the inner peripheral edge. Become. In addition, the first portion connected by the step portion 26
In the example shown in FIG. 3, each of the first groove 22 and the second groove 24 has a certain depth.
Although it is configured to have a bottom, it is not limited to this . The first groove 22 and the second groove 24 via the step portion 26 are formed in a tapered shape such that one or both of them have a gradually decreasing depth from the outer peripheral side toward the inside. You may comprise. In the example shown in FIG.
2 is constant , and the depth of the second groove 24 is tapered. In the example shown in FIG. 9, both the first groove 22 and the second groove 24 have a tapered depth. These points are the same when the second groove 24 is the second groove 25 shown in FIG.

FIG. 4 shows an axially movable seal ring and another seal ring with another simple spiral groove facing the seal ring, the seal rings being separated by a gap C. The spiral grooves shown therein have dimensions A and B. The axial force in equilibrium is depicted on both sides of the two axially movable seal rings. This axial force is indicated by a number of arrows within the indicated pressure distribution in the longitudinal direction of the seal ring. As these pressure distributions change, the force balance also changes, and the resulting force difference moves the seal ring such that the face spacing is readjusted, thereby restoring the force equilibrium again. Of the wide range of times when the sealing action takes place, the most important time is when the shaft begins to rotate. Usually, at that point, the seal already has a pressure differential. What is necessary to start the rotation of the shaft is that when the gap between the sealing end faces is to be opened, the force for closing the gap is almost equal to the force for opening the gap. Having a gap C or zero gap. On the other hand, what must be avoided is a large sealed end gap with a large amount of leakage. It is also a zero gap with a closing force that is much greater than the opening force. In this case, the sealing end faces are locked together by friction and the seal is damaged when the shaft is rotated.

The condition of zero clearance when the opening between the sealing end faces is about to open is the preferred condition, and according to the invention this can be achieved for a wide range of sealing pressures. is there. In this Conde Deployment, the device is completely in a state of under pressure, most leaks also rather than, or production losses even without, in a state in which it is possible to start the operation at any time, it is possible to wait. The start-up condition, ie the state at start-up, is governed by the hydrostatic principle since the shaft has not yet rotated. The spiral groove serves as an introducing means for introducing a gap between the sealing end faces. According to FIG. 4, this gap is larger in the groove area and narrower in the non-groove area, and the groove determines the ratio of the outer gap to the inner gap. The hydrostatic principle teaches here that the spiral groove is made deeper or shallower, i.e. that the ratio of the outer gap to the inner gap is changed by changing the dimension B in FIG. And consequently the gap C changes. The change is
When the dimension B increases, the gap C increases, and when the dimension B increases, the gap C decreases. A similar situation occurs when the depth of the spiral groove decreases on the way inward from the outer peripheral edge. That is, the equilibrium gap C increases as the depth of the groove at the outer peripheral edge increases and the depth of the groove rapidly decreases inward. In the opposite case, the equilibrium gap C becomes narrow.

The spiral groove pattern of relatively large size A and relatively small size B in FIG. 4 imparts unique hydrostatic properties to the seal. That is, the gap C in a hydrostatic situation becomes very narrow and approaches the average gap based on the roughness of the two sealed end faces. This situation is shown enlarged in FIG. No matter how smooth, there can be no perfectly smooth surface. The sealing end face always has a certain degree of roughness with small irregularities,
Such two contact surfaces always leave a path for producing a small fluid flow between the roughness protrusions. The dimension S indicates the average gap due to the rough surface effect.

It is an object of the present invention to design the gap C in a hydrostatic situation to approach the above-mentioned dimension S in the pressure range as wide as possible without excessive opening between the sealing end faces. That is, although the space between the sealing end faces is closed, the force in the opening direction and the force in the closing direction are substantially balanced, and the closing is performed in a state where the sealing end face is not locked by friction. The above is demonstrated in FIG. FIG. 5 shows the change in the gap of the sealed area due to the pressure change for individual spiral groove patterns as well as for the new combination of groove patterns according to the invention. The figure shows eight curves, two for each of the three single pattern grooves and the other two for the combination pattern grooves. One of these curves coincides with the vertical axis and the other two coincide with each other.
Therefore, only six curves are drawn in FIG. Corresponding to these curves, the pattern of the spiral groove is shown in a sectional view at the upper side of FIG. 5 together with dimensional information.

First, the spiral groove pattern A is composed of 76.
2mm (3 inch) groove diameter and 0.000254mm
It is designed so that a hydrostatic separation force can be obtained at a groove depth of (0.00001 inch). The gap-pressure characteristic at zero rotation speed of the pattern A is represented by a line A1.
Is shown in The characteristic of this is 2.8122784k
At a pressure of g · cm ⁻² (40 psig), there is already a small gap between the sealing end faces. The gap is calculated and the actual sealing end face will have some surface roughness, but the small gap mentioned above is not necessarily large enough to eliminate surface contact, but the gap closing force and gap opening Enough to bring the power and
It will be sufficient to eliminate the risk of locking of the sealing end face and breakage of the seal. In fact, the hydrostatic separation force in the spiral groove pattern A provides the ideal condition for light surface contact, and therefore only a very small fluid leakage between the sealing face roughness, which is also a small or large degree of surface contact. Fluid leakage that does not change much. The sealing end face is in a state of just opening over a wide pressure range, and the shaft can start rotating at any of these pressures without the risk of breaking the seal. Increasing the depth in the groove pattern A causes a large separation of the sealing end faces, leading to a large leakage and also an undesirable situation for a device which will have to be kept under pressure for a long period of time.

It should be noted that the pattern A does not need to have a spiral shape in order to achieve its effect. As shown in FIG. 7, similar to FIG. 2, a pattern of shallow radial grooves 25 connecting to the deep outer first grooves 22 is also hydrostatically effective. The radial groove 25 in FIG. 7 is obtained by increasing the spiral angle of the groove 24 in FIG. Of course, an intermediate groove shape between these two grooves 24 and 25 is also effective. The line A2 shows the full-speed rotation characteristics for the groove pattern A. According to the dynamics of high speed shaft rotation, a certain minimum clearance is required for the non-contact sealing action to occur, and the clearance indicated by A2 is not sufficient. Therefore, the groove pattern A itself is not suitable.

The groove pattern B is 86.868 mm (3.4
2 inch) groove diameter, 0.00508 mm (0.00 inch)
The pattern B is designed to be optimal at full speed rotation. For this reason, the groove is made relatively deep so as to supply a sufficient amount of fluid to the sealed area so as to sufficiently separate the sealed end faces at full speed rotation. Also, the grooves are relatively short in size, thereby providing a minimally possible hydrostatic effect that eliminates interference with any other groove pattern that may be combined. The groove pattern B does not hydrostatically separate the sealed end faces. Therefore, line B1 coincides with the vertical axis and is a zero gap at all pressures. Such a groove pattern B causes locking of the sealed end face at most pressures. Therefore, the groove pattern B is also unsuitable by itself. It should be noted that the full speed rotation characteristic shown by the line B2 indicates a sufficient sealing end gap for the non-contact action of the hydrodynamic seal.

The groove pattern AB is a combination of the pattern A and the pattern B. The line AB1 indicating the hydrostatic separation characteristic is on the right side of the line A1.
This is because the effect of the groove pattern B pattern remains slightly. On the other hand, the line AB2 showing the hydrodynamic separation characteristic almost coincides with the line B2,
The gap in B2 is only slightly larger than the gap in B2 by less than 5%. Therefore, this groove pattern AB2 is
An improvement over the current one, meeting both the criteria of hydrostatic separation to prevent locking of the sealed end face and the criteria of satisfactory hydrodynamic clearance with low leakage It is shown that is performed.

For comparison, a current simple groove pattern C is shown. The groove pattern C is 80.9752 mm (3.1
88 inch) groove diameter and 0.00508 mm (0.00
A line having a groove depth of 02 inches) and showing hydrostatic separation characteristics is indicated by C1 and a line indicating hydrodynamic separation characteristics is indicated by C2 and a broken line. The groove pattern C is designed so that the sealed end face can be separated sufficiently hydrostatically so that the operation can be reliably started in a state where the total pressure is applied. Attempts to further shorten this groove pattern C to reduce leakage will cause hydrostatic locking of the sealed end face. What must be specified is how deep grooves for hydrodynamic action are not suitable for hydrostatic separation.
As shown by line C1, the sealing end surface tends to open only at high pressure, but the opening of the gap is sharp. The need to increase the length of the groove pattern C in order to sufficiently prevent locking of the sealing end face also disadvantageously detracts from the hydrodynamic effect and shifts the line C2 significantly to the right relative to the lines B2 and AB2.
The amount of leakage varies according to about the cube of the gap, so
At 0696 kg · cm ⁻² (1000 psig), the increase in gap from line B2 (AB2) to line C2 is almost 1
This means a 70% increase in leakage.

As is apparent, the groove pattern AB according to the present invention can significantly suppress leakage as compared with the existing groove pattern C. Also a hydrodynamic aspect?
In these separation characteristics, it is close to the line AB2 of the groove pattern AB.
The simple groove pattern B having a line B2 cannot be used.
This is because the groove pattern B does not provide a sufficient hydrostatic separation of the sealing end face, but does provide a locking of the sealing end face in the rotation stopped state. Also a simple groove pattern A
Also cannot be used. This is because the groove pattern A only hydrostatically prevents the locking of the sealed end face (see line A1) ,
This is because a hydrodynamic non-contact action at all pressures and all rotational speeds cannot be ensured.

[0029]

According to the mechanical seal device of the present invention, the first deep groove 22 and the second shallow groove 24, which are spiral grooves, are provided.
25 and the start of operation,
The lock between the sealing end faces 21 and 19 is obtained by the hydrostatic action of the shallow second grooves 24 and 25 at the time of low rotation at the stop and by the hydrodynamic action of the deep first grooves 22 at the full rotation. Wear and the like can be prevented and a large amount of leakage of the sealed fluid can be prevented. Therefore, stable fluid sealing performance can be obtained under a wide range of operating conditions from the operation stop state to full speed rotation. Especially,
According to the configuration of the first aspect, the shallow second grooves 24 and 25 are connected to the end of the deep first groove 22, so that two different types of grooves, that is, the first groove are provided. Since the single groove 22 and the second grooves 24 and 25 are formed as one single pattern extending inward from the outer peripheral edge, the structure becomes very simple, and a plurality of different types of grooves are formed in a circle. Compared with a multi-patterned pattern that is gathered in the circumferential direction, the formation or production of the groove on the sealing end face becomes very easy, and the defect rate can be reduced accordingly. In addition, according to the configuration of the first aspect, different first types are used.
The groove 22 and the second grooves 24 and 25 are formed as one single pattern inward from the outer peripheral edge, so that a plurality of different types of grooves are gathered in the circumferential direction. As compared with the multi-pattern, a larger number of groove patterns can be formed in the circumferential direction of the sealed end face, and the uniformity of the fluid bearing action in the circumferential direction can be improved. Furthermore, since the first groove 22 and the second grooves 24 and 25 are different types of grooves depending on the depth of the grooves, it is necessary to use a wide width groove in order to make the type of groove different depending on the groove width. Therefore, the occupied area of each pattern in the circumferential direction can be reduced, so that a large number of groove patterns can be formed in the circumferential direction, and the same uniformity in the circumferential direction as described above is further improved. be able to. Further, according to the configuration of the first aspect, the deep first groove 22 and the second grooves 24 and 25 extending inward from the outer peripheral edge are connected to each other via the stepped portion 26, so that during rotation, Therefore, it is possible to sufficiently suppress the sealing fluid from going from the deep first groove 22 to the shallow second grooves 24, 25, and as a result, a sufficiently effective fluid power is provided in the deep first groove 22. Dynamic pressure can be generated efficiently. The first groove 22 and a sufficient depth of the groove to form a hydrodynamic fluid bearing further by the front Kidan unit 26, also the second grooves 24, 25 a hydrostatic fluid bearing Since the first groove 22 can be divided into a sufficiently shallow groove to be formed, an effective hydrodynamic sealing action at a high rotation speed by the sufficiently deep first groove 22 and a sufficiently shallow second groove 24 , 25, effective hydrostatic sealing at the time of shutdown, start-up, etc., and without mutual adverse effects due to the mutual grooves (22, 24, 25). According to the configuration of the second aspect, in addition to the effect of the configuration of the first aspect, the depth of the first groove 22 is set to 0.1. Since it does not exceed 0254 mm, the hydrodynamic sealing effect of the first groove 22 can be performed without significant side effects. According to a third aspect of the present invention, in the first aspect,
Or, in addition to the effect of the configuration described in 2 above, the first groove 2
Depth of 2 in a range of from 0.0025 4mm ~0.0076 2mm, during full speed, seal end faces 2
The gap between the sealing end face 2 and the gap in a range that can sufficiently prevent the lock, high friction, and abrasion between the first and the 19th to ensure the stable high-speed rotation and sufficiently prevent the leakage of the sealed fluid can be obtained.
1. The hydrodynamic pressure that can be reliably introduced between 19 and
It can be generated in the first groove 22. Claim 4
According to the configuration described in (1), in addition to the effect of the configuration described in any one of claims 1 to 3, the depth of the second grooves 24 and 25 is set to be in a range of 0.000254 mm to 0.001778 mm. Thus, when the operation is stopped or at the time of low-speed rotation at the start and stop of the operation, the lock, high friction, and wear between the sealed end faces 21 and 19 can be sufficiently prevented, and the leakage of the sealed fluid can be sufficiently suppressed. Seal end face 2 with gap
1. The hydrodynamic pressure that can be reliably introduced between 19 and
It can be generated in the second groove 22. Claim 5
According to the configuration described in (1), in addition to the effect of the configuration described in any one of claims 1 to 4, the depth ratio between the second grooves 24 and 25 and the first groove 22 is set to 0.05. By setting the range to 0.25, the second grooves 24 and 25 are sufficiently shallower than the first grooves 22, and the first grooves 22 are sufficiently deeper than the second grooves 24 and 25. , And between them a sufficiently deep step 26 can be formed, whereby the hydrodynamic action of the relatively deep first groove 22 and the hydrostatic effect of the relatively shallow second grooves 24, 25 are achieved. The mechanical action and the mechanical action can be performed sufficiently effectively without adversely affecting each other. In addition, according to the configuration of claim 6,
In addition to the effect of the configuration according to any one of claims 1 to 5, a second groove 24 is extended spirally at the end of the first groove 22 so that one smoothly continuous groove is formed. You can get a pattern. According to the configuration described in claim 7, the effect of the configuration described in any one of claims 1 to 5 can be obtained by adding the second groove 25 to the inner peripheral edge at the end of the first groove 22 in the radial direction. It can also be obtained by extending the extension. Further, according to the configuration of the eighth aspect, the effect of the configuration of any one of the first to seventh aspects is reduced by the first effect.
The groove 22 and the second grooves 24 and 25 can be obtained even when the depth of each is constant . According to the ninth aspect of the present invention, the effect of the first aspect is provided by the depth of at least one of the first groove 22 and the second grooves 24 and 25. Can also be obtained in a tapered shape so that the depth gradually becomes inward from the outer peripheral side.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional configuration diagram showing a configuration in a longitudinal direction of a mechanical seal device manufactured according to the present invention, and shows a relative position of each part when a shaft rotates.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a view showing a comparative example, and is a schematic side view showing a sealed area, a seal ring, and an axial force acting on the seal ring.

FIG. 5 is a pressure-gap diagram showing hydrostatically and hydrodynamically generated gaps for four different spiral groove patterns.

FIG. 6 is an enlarged view showing an example of two flat surfaces that come into contact with each other.

FIG. 7 is a diagram showing another embodiment similar to FIG. 2;

FIG. 8 is a diagram showing another embodiment similar to FIG. 3;

FIG. 9 is a view showing still another embodiment similar to FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Housing 12 Shaft 14 Annular space 16 Ambient environment part 18 2nd seal ring 19 2nd sealing end face 20 1st sealing ring 21 1st sealing end face 22 1st groove 24 2nd groove 25 2nd Groove 26 Step 28 Step 30 Spring

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-236067 (JP, A) JP-A-4-54382 (JP, A) JP-A-4-54366 (JP, U) JP-A-2-236667 74664 (JP, U) JP-B-47-48808 (JP, B1) JP-B-36-6305 (JP, B1) European Patent Application Publication 369295 (EP, A) West German Patent Application Publication 369295 (DE, A1) (58) Field surveyed (Int.Cl. ⁶ , DB name) F16J 15/34

Claims (9)

(57) [Claims] A first seal ring attached to the rotary shaft and having a flat first sealed end face for sealing a fluid to be sealed between the housing and the rotary shaft; On the housing 10 side, a flat second sealing end face 19 is disposed coaxially with the first sealing ring 20 and is disposed adjacent to and axially opposed to the first sealing end face 21 in the axial direction. A second seal ring 18; the first seal ring 20 or the second seal ring 1
8 is made movable in the axial direction, and this movable seal ring is urged toward the other seal ring by the elasticity applying means 30, and the first and second sealed end faces facing each other. 21, 19
A mechanical seal device that forms an annular sealed area between the outer peripheral edge and the inner peripheral edge of the sealed end faces 21 and 19, wherein any one of the first and second sealed end faces 21 and 19 is formed.
1, a first groove 22 extending spirally inward from an outer peripheral edge on the side in contact with the sealed fluid and formed at intervals in the circumferential direction; A plurality of second grooves 24, 25 formed on the sealing end face 21
The first groove 22 and the second grooves 24 and 25 are provided with the closed
The first groove 22 that starts from the outer peripheral edge in contact with the sealing fluid
By extension without further lead to the inner peripheral edge inwardly causes initiated by connecting the second grooves 24, 25 at the end of that against, inward from an outer peripheral edge of the sealed fluid contacts To form a single groove pattern toward
Groove 22 and the second grooves 24, 25 are connected via a step 26, and the step 26 allows the first groove 22 to be deep enough to form a hydrodynamic fluid bearing. A mechanical seal device characterized in that the second grooves 24 and 25 are shallow enough to form a hydrostatic hydrodynamic bearing. 2. The depth of the first groove 22 is 0.0254 m.
The mechanical seal device according to claim 1, wherein the value does not exceed m. 3. The depth of the first groove 22 is 0.00254.
The mechanical seal device according to claim 1, wherein the mechanical seal device has a range of mm to 0.00762 mm. 4. The depth of the second grooves 24, 25 is 0.00
The mechanical seal device according to any one of claims 1 to 3, wherein the mechanical seal device has a range of 0254 mm to 0.001778 mm. 5. The depth ratio of the second grooves 24, 25 to the first grooves 22 is in the range of 0.05 to 0.25.
5. The mechanical seal device according to any one of 4. 6. The mechanical seal device according to claim 1, wherein the second groove 24 extends inward in a spiral shape continuously from the first groove 22. 7. The mechanical seal device according to claim 1, wherein the second groove 25 extends radially toward the inner peripheral edge. 8. The mechanical seal device according to claim 1, wherein each of the first groove 22 and the second grooves 24 and 25 has a constant depth. 9. Any of the first groove 22 and the second at least one claim is gradually shallower so as to taper the depth from the outer peripheral edge inwardly of the groove 24, 25 1-7
The mechanical seal device as set forth in either.