JP3050407B2 - Seal / bearing assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to seals and bearings for rotating shafts and is particularly suitable for use in motor driven centrifugal pumps.

BACKGROUND OF THE INVENTION There is an increasing demand for seals configured to be damaging to release harmful fluids into the environment. Apart from such new requirements, there are general requirements in seal design. That is, the seal must withstand the longest possible service life without failure; when the seal begins to leak, it must not withstand the leakage flow and tear severely;
It must be repaired at a low price. The length of disassembly time required to expose the seal is the time when the device or equipment is not used. The seal / bearing assembly of the present invention addresses such various needs, as will be described.

General features of the present invention It is an object of the present invention to provide a means for generating a large pressure in the packing box of a centrifugal pump, i.e. greater than the pressure of the process fluid.

An object of the present invention is to obtain the above high pressure without using a viscous lubricating barrier liquid, and to obtain a high pressure even when water is used as the barrier liquid.

It is an object of the present invention to provide a means for controlling the pressure in the packing box and controlling such pressure with respect to the pressure of the process fluid as well as the pressure of the external environment.

The present invention provides a combined seal / bearing assembly device that includes a stator and a rotor adapted to rotate about an axis. The device can be mounted instead of the packing box of the centrifugal pump.

The components of the rotor and the stator are formed with complementary shaped bearing surfaces, which are arranged to clean each other in a hydrodynamic bearing relationship over an area called the bearing area.

A groove is formed in one of the bearing surfaces and extends in a spiral form along and around the bearing surface in the bearing area. The spiral groove has several turns extending over the bearing surface, such a row of turns so as to leave a land of sufficient width between adjacent turns of the spiral groove. Are arranged. The spiral groove has an inlet mouse and an outlet mouse.

The apparatus is configured to define an inlet chamber and an outlet chamber, both of which are in fluid communication with the inlet and outlet mice, respectively. The apparatus also includes means for transporting the barrier liquid into the inlet chamber and transporting the barrier liquid from the outlet chamber.

When the device is driven and rotated, the barrier liquid is
It flows along the spiral groove from the entrance mouse to the exit mouse.

In the present invention, the device is configured so that the fitting between the two bearing surfaces is a tight operating gap, the gap between the two bearing surfaces, that is, the gap is sufficiently small,
The land width between each convolution is sufficiently large to ensure a continuous hydrodynamic film between the bearing surfaces.

The bearing surface is preferably tapered in a conical shape so that the rotor or stator can move axially into and out of the taper.

Relationship of the present invention to the prior art The prior art comprises a structure that uses threads to push the process fluid out of the packing box seal. The threads act in the manner of a propeller or in the form of an Archimedes screw to move process fluid into and out of the impeller chamber. One example is described in US Pat. No. 3,558,238 (197
One year, Van Herpt).

Other conventional constructions use Archimedes screws to generate enough force to slide the sleeve axially along the shaft, thereby releasing the forces acting between the spring-loaded sealing surfaces. ing. In such a structure, the reaction to the force serves to return the fluid to the impeller. Thus, the faster the shaft rotates, the more fluid is pushed back out of the seal and more seal contact force is released. Examples of such structures are shown in U.S. Pat. No. 3,746,350 (Mayer +, 1973) and U.S. Pat. No. 4,243,230 (Baker +, 1981).

A shallow groove in the form of a spiral is formed in the sealing surface,
It serves to move the liquid present on the sealing surface in a desired direction. Examples of such are U.S. Pat. No. 4,290,611 (1981, Sedy) and U.S. Pat. No. 4,249,812 (1993, V.
olden +) and US Reissue Patent No. 34,319 (1993
Year, Boutin +).

A method of using a very small radial clearance between the rotating elements to promote flow in a desired manner is shown in US Pat. No. 5,372,730 (Warner +, 1994).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS To further illustrate the present invention, a representative embodiment of the present invention will be described below with reference to the accompanying drawings, in which: FIG. FIG. 2 is a side sectional view of an apparatus suitable for use in the installation of FIG. 1; FIG. 3 is a view similar to FIG. 2 showing another apparatus; FIG. 5 is a diagram of an element suitable for use in the apparatus, FIG. 5 is a diagram of another device suitable for use in the facility, and FIG. 6 is a diagram of another suitable device. 7 is a circuit diagram, FIG. 8 is a diagram of another suitable device, FIG. 9 is a diagram of another suitable device, and FIG. 10 is a diagram of another suitable device. FIG. 11 is a diagram of another device on which another structure is mounted, FIG. 12 is a diagram of another type of device, and FIG. 13 is a diagram suitable for use in this device. FIG. 9 is a diagram of another element that has been added.

The apparatus shown in the accompanying drawings and described below is an example embodying the present invention. It is to be understood that the scope of the present invention is defined by the appended claims, and not necessarily by the specific features of the exemplary embodiments.

FIG. 1 shows a pump / motor installation. The electric motor 20 is mounted on a base frame 23, and a bearing box 25 and a centrifugal pump 27 are also mounted on the base frame. The armature of the motor is connected via a coupling 30 to the drive shaft 29 of the pump.

The rotating shaft 29 is sealed with a packing box 32. It is to the design with such packing boxes that the present invention is concerned.

FIG. 2 shows an example of the invention applied to a pump / bearing box situation. The pump impeller 34 is connected to the shaft 29
It is keyed to. The inner rotating sleeve 36 is also keyed to the shaft 29. Fixed outer sleeve 38
Is keyed to the housing 40 of the pump 27.

The inner surface of the outer sleeve 38 is flat. On the outer surface 43 of the rotating sleeve 36, a (single) spiral groove is formed. The mouse 47 on the left side of the groove 45 is open to the entrance chamber 49. The mouse 50 on the right side of the groove 45 is open to the outlet chamber 52.

The inlet chamber 49 has a normal rubber lip seal 54
Is sealed to the outside. The inlet chamber 49 is connected via a port 56 to a source of barrier liquid. The outlet chamber 52 is open to the interior of the impeller housing 40, ie, to the process fluid being pumped by the pump 27.

The rotor and stator, and the inner and outer sleeves are sealed to the shaft and housing by O-rings 58, respectively.

In use, the shaft 29 is driven and rotated by an electric motor, which causes the sleeve 36 to rotate.
Thus, the groove 45 and its helical form means rotate, whereby liquid molecules located in the groove are conveyed along the groove. The rotation direction of the motor 20 is such that the molecules are directed to the right (in the direction of the drawing), ie, the inlet chamber.
From 49, it is conveyed toward the outlet chamber 52.

The function of the spiral groove 45 in transporting the molecules of the barrier liquid to the right side serves to make the pressure of the barrier liquid in the outlet chamber 52 higher than the pressure of the barrier liquid in the inlet chamber 49. In practice, the pressure of the barrier liquid in the inlet chamber where the barrier liquid is picked up by the groove is at or near atmospheric pressure, and the pressure in the outlet chamber where the barrier liquid exits the groove is the pressure of the spiral groove. The pressure of the process fluid can be exceeded.

Therefore, the pair of sleeves 36 and 38
It acts as a very effective seal against leakage of process fluid through. As long as shaft 29 is rotating and barrier liquid is being supplied to port 56, outlet chamber 52
Is filled with the pressurized barrier liquid.

If the process fluid is stopped (ie, if the outlet pipe conveying the process fluid away from the pump is closed), the helical grooved sleeves 36, 38 will still pump the barrier liquid into the outlet chamber 52. Play a role.

If the inlet pipe of the pump is blocked and a vacuum is created inside the pump, i.e. the impeller chamber, and cavitation occurs, the barrier liquid will still be pumped to the outlet chamber. In contrast, in some prior art designs, cavitation in the suction line of the pump causes liquid to be drawn out of the packing box, causing cavitation in the packing box, and Finally, the sealing function of the packing box may be reduced.

The barrier liquid is easy to maintain in a clean state (eg, by filtration). The barrier liquid is pushed out of the outlet mouth 50 of the groove 45. Therefore, sleeve 3
6, 38 and surfaces 42, 43 are kept free of particles that may be present in the process fluid. Process fluids are often dirty and may contain particles or other harmful substances, which are filtered before the process fluid enters the grooves or surfaces 42, 43. You.

The barrier liquid fills the groove 45 and also forms the outer sleeve 38.
Between the inner side surface 42 and the outer side surface 43 of the inner sleeve 38, or at least, between the surface 42 and the land 43A of the surface 43 existing between the respective convolutions of the groove 45, a hydrodynamic membrane. Form.

Barrier liquid is supplied to the inlet chamber 49 and is drawn into the inlet mouth 47 of the channel. As a result, neither part of the bearing surface, that is, any part of the area to be cleaned on the surfaces 42 and 43 is dried. In fact, when the pump is cavitation (ie, when it is not drawing any process fluid)
However, no part of the bearing surface dries.

The barrier liquid is at or near atmospheric pressure
Supplied to 56. The barrier liquid does not need to be pre-pressurized outside the packing box to a pressure higher than the process pressure, and the function of the spiral groove 45 plays a role in pressurizing the barrier liquid. In fact, port 56 can be connected to a supply pipe that is simply immersed in a reservoir of barrier liquid,
The level of liquid in the reservoir can be below the level of the port, whereby the barrier liquid is drawn into the inlet chamber 49 at a pressure slightly below atmospheric pressure. (The lip seal 54 will be selected based on the need to maintain a slight vacuum.) The limitation of the action of the rotating helical groove shown in FIG. When passed, the barrier liquid cannot exit the outlet mouth 40 of the groove 45.

Also, if the pressure of the process fluid is higher than the pressure generated by the groove, the process fluid
Tend to enter the interface between the surface and the surface 42 to form its own hydrodynamic membrane. This membrane, in particular,
If the process fluid has low viscosity or lubricity, it will subsequently break or be blown away.

The smaller the gap between the surfaces 42, 43, the higher the pressure required to expel the hydrodynamic membrane. A cylindrical (ie, not tapered) surface 42,
In the case of 43, the clearance (gap) between such surfaces should be less than about 0.1 mm (or even lower if more severe use conditions are anticipated).
Reduction is not practically possible.

In the case of using the above-described gap or gap and using lubricating oil as the barrier liquid, the spiral groove is
It has also been observed that liquids can enter the outlet chamber at pressures of tens of psi, such as 80 or 100 psi (100 psi = 690 kN / square meter). Such pressure is sufficient to prevent process fluid leakage even if the pump has failed.

However, it has been found that if the barrier liquid has a viscosity lower than that of the lubricating oil, only a relatively low pressure is maintained when the gap is on the order of 0.1 mm. For example, it has been found that when using water as the barrier liquid, the pressure in the outlet chamber cannot be about 2 or 3 psi higher than the pressure in the inlet chamber. This is not enough to prevent the process fluid from leaking into the helical grooves and bearing interfaces.

In the configuration shown in FIG. 2, upon exiting the outlet chamber 52, the barrier liquid enters the process fluid. Therefore, FIG.
In, the barrier liquid must be of a type that is acceptable in the process fluid. The amount of barrier liquid entering the process fluid is small when compared to the flow rate of the process fluid being pumped, but in many cases the process fluid is a lubricating oil or other viscous liquid with only a small trace But they are not allowed to enter the process fluid.

In many industrial pumping installations, the pumped process fluid is water or a water-based liquid. Lubricants (even traces) are often not allowed into water. However, 0.1m
When a gap between bearing surfaces of the order of m is used, the water itself is almost useless as a barrier liquid. If water is the barrier liquid, a gap much smaller than 0.1 mm is required to generate an effective pressure in the outlet chamber 52. However, cylindrical surfaces arranged in the form of male / female bearings, even when manufactured with high precision, cannot actually have gaps smaller than the values mentioned above. Cylindrical surfaces can be used when traces of lubricating oil are allowed in the process fluid.
Although it can be used, such cases only occur with a very small percentage of pumping equipment. Cylindrical surfaces are rarely used when the barrier liquid is water.

In FIG. 2, the (flat) stator / sleeve 38 is fixed in the housing, while the rotor / sleeve 38
36 is free to slide axially on shaft 29 (however, it is keyed to rotate with the shaft). A spring 65 pushes the rotor / sleeve into the taper.

The tapered surfaces 42, 43 overlap each other like a combined pair, so that the fit between such tapered surfaces is very much over the cleaned interface of such surfaces, or the entire bearing surface. Good.

In FIG. 2, a hydrodynamic film naturally forms between the tapered surfaces during rotation. Such a hydrodynamic membrane can be made thinner or thicker as needed, depending on conditions such as the viscosity of the barrier liquid, process pressure, rotational speed, groove dimensions, and the like. Even if water with very low viscosity and lubricity is a barrier liquid,
It has been found that between 2 and 43 a membrane is created independently and an adjustable pressure is created in the outlet chamber 52.

Indeed, it has been found that a pressure of 60 psi or more is easily achieved in the outlet chamber if the barrier liquid is water and the pump fails. It was also found that during normal rotation the hydrodynamic membrane was very strong and there was no evidence of direct contact between surfaces 42 and 43 after prolonged operation.

However, direct contact between the surfaces 42, 43 is unavoidable, and the sleeve must be formed from a material that allows accidental contact without seizure, smearing, pickup, etc. Must. For example, one sleeve can be formed from cast iron and the other sleeve can be formed from bronze. Alternatively, a plastic bearing material, such as PTFE, can be used.

In fact, even in the case of water, although very thin, surface 42,
The hydrodynamic membrane that occurs uniquely at the interface between 43 turns out that such interface is not strong enough to act as a real journal bearing for the impeller shaft 29 Was.

FIG. 2 shows a conceptual bearing 67 housed in the bearing housing 25 and, in conventional installations, well behind the impeller. That is, impeller 34
Is attached to one end of the long overhang of the shaft. Thus, the impeller may be subject to vibrations of a period and amplitude of interest.

The sleeves 36, 38 can be considered to act to assist the bearing. That is, the bearing formed by the sleeve acts to assist bearing 67 by cushioning some of the excess vibration. However, it has been found that in most cases, the bearing 67 is not actually provided. Even in the case of barrier liquid water, the pump shaft and the impeller are properly supported by bearings formed by the sleeve.

One reason for such excellent support is that the bearings are very close to the impeller. In FIG. 2, there is no need to provide a separate packing box / seal, so that the bearing is separated from the impeller by at least the width of the seal, and in FIG. One is the same.

Even if cavitation occurs on the suction side of the pump, possible unbalanced loads and other adverse conditions that induce vibration do not result in oscillating biasing motion of the shaft and impeller because the bearing However, it is very close to the impeller. The shaft operates smoothly and uniformly in conditions where a conventional pump would leak its packing box / seal.

The spiral groove of the tapered sleeve serves to carry the barrier liquid along the groove from the inlet mouth to the outlet mouth. The distance the barrier liquid moves per rotation of the groove is
It is necessary to understand that it fluctuates because of its tapered shape. That is, the length of one rotation of the groove at the narrow end of the taper is shorter than the length of one rotation of the groove at the thick end.

With this in mind, the designer must ensure that the cross-sectional area of the groove increases slightly toward the tapered end to compensate for the decreasing ring length. FIG.
Shows a state in which the groove 70 is formed slightly deep at the narrow end.

The sleeve and groove and the direction of rotation of the motor must be set so that the groove carries the barrier liquid towards the impeller. In doing so, as shown in FIG. 4, the designer can configure such a sleeve such that the sleeves 72, 73 carry the barrier liquid toward the tapered end. Again, the groove 70 must be slightly larger in area (forming slightly deeper) at the narrow end to compensate for the reduction in loop length.

In another embodiment (not shown), the rotor sleeve can be an outer sleeve and the stator can be an inner sleeve. In this case, the groove is formed on the inner surface of the outer sleeve, which is much more difficult than forming the groove on the outer surface. However, for best hydrodynamic effects, the designer sometimes prefers to form a groove (spiral or loop) on the inside surface of the outer stator sleeve, such as sleeve 38 in FIG. .

It may be desirable to protect the system from leaking process fluids even when the motor stops rotating. For example, the system of FIG. 2 allows the process fluid to flow back and leak through the spiral groove if rotation stops.

As shown in FIG. 5, a lip seal 74 is provided between the outlet chamber 52 and the inside of the pump housing 40, that is, between the impeller chamber, in order to prevent leakage when the motor stops.

During normal operation, the pressure generated in the outlet chamber 52 is higher than the pressure generated in the impeller chamber, opening the sealing lip and allowing the barrier liquid to flow into the impeller chamber. When rotation stops, high pressure in the impeller chamber at this point closes the lip seal, thereby preventing fluid in the impeller chamber from entering the outlet chamber.

FIG. 6 shows another way in which the elements can be formed. In this case, the rotor sleeve 76 is
It is formed integrally with 78. Outer stator sleeve 80
Are spring loaded into the taper. It can be seen that a simple, flat diameter 79 without shoulders at the end of the impeller can be provided in the packing box housing.

As an alternative to FIG. 6 (not shown), the stator sleeve can be formed in the packing box housing. However, since the sleeve is tapered,
It is not recommended to form the rotor surface on the impeller and the stator surface on the housing, because if the advantage of a tapered shape is obtained, one of the above-mentioned surfaces can be freely free in the axial direction. This is because it must be slid.

In the illustrated assembly, as long as the barrier liquid has the proper viscosity and lubricity, this structure is extremely reliable for all process fluid conditions that may be encountered in real equipment. It is expected to give a seal with a certain quality. Note, however, that if the supply of barrier liquid is stopped, the mouth mouth of the groove will dry and the entire bearing area between the surfaces may dry, or part of such an area may dry. It is important to. If such an event occurs, the pressure in the outlet chamber 52 will drop, and perhaps the process fluid will enter the spiral groove and even leak (to the left) from the packing box seal. When the surfaces are wholly or partially dried, their service life is considerably reduced.

Therefore, the designer must take care that the barrier liquid in the inlet chamber 49 does not run out.

In the appropriate case, the barrier liquid can be taken from the process fluid. Of course, this is the case when the process fluid is a lubricating oil, but some other types of liquids may be appropriate.

If the process fluid is lubricating oil, the inlet chamber
It can be considered that drying 49 (FIG. 2) is not a problem. The reason is that such process fluid enters the groove 45 from the outlet end and lubricates the bearing surface. However, if the inlet chamber is dry, even if the process fluid is a lubricating oil, such a process fluid will
It is not anticipated that the entire cleaned area of the bearing surface will reach and wet the area, and therefore dry contact of the bearing surface cannot be avoided. By ensuring that the inlet chamber 49 is filled, the designer keeps the hydrodynamic membrane intact to prevent bearing surface contact.

FIG. 7 shows a system for maintaining the inlet chamber filled with barrier liquid. In this case,
Barrier liquid is supplied from the process fluid via pipe 83 and also from a separate source 85. The supply is controlled by valves, as shown, which can be controlled manually or automatically as required.

The barrier liquid passes through the temperature controller 86 and further passes through the filter 87. It is important to filter and clean the barrier liquid, as foreign particles trapped between the bearing surfaces impair the self-retaining properties of the hydrodynamic membrane.

The pressure of the barrier liquid in the inlet chamber 49 is controlled by a separate regulator 89. Instead, the pressure in the inlet chamber may be controlled by aspirating the barrier liquid from that liquid level. The height of such a level determines the head or pressure.

The above design is where the barrier liquid is capable of leaking into the process fluid, where in fact the process fluid is the source of the barrier liquid. However, while the above design is a very simple structure to mechanically construct, its applicability is less common. In most cases, it is necessary that the process fluid is not diluted with the barrier liquid, and
Not suitable for use as a barrier liquid.

FIG. 7 also shows a means for controlling the barrier liquid when the barrier liquid is to be kept separate from the process fluid. If the barrier liquid and the process fluid are separate, especially if the barrier liquid is based on water, additives may be added to the barrier liquid as needed to improve its properties with respect to viscosity and lubricity be able to. The barrier liquid is recirculated by aspirating liquid from the outlet chamber via pipe 82 while maintaining the pressure in the outlet chamber at the desired value by regulator 84.

Instead of a single lip seal 74 (FIG. 5), a back-to-back lip seal can be provided between the impeller chamber and the outlet chamber. Similarly, a back-to-back lip seal can be provided at the other end of the tapered sleeve to seal the inlet chamber 49 (FIG. 2) to prevent inward and outward leakage.

Lip seals can only withstand a differential pressure of a few psi.
It is therefore important to protect such seals from large differential pressures. This is achieved by the pressure regulator shown.
Preferably, it is performed automatically. Outlet chamber 52
Is compared to the pressure in the impeller chamber 49, and the outlet pressure is adjusted so that the pressure in the outlet chamber is several psi higher than the pressure in the impeller chamber.
Second, if the seal breaks, the process fluid will not leak into the packing box. If the leakage of the process fluid into the barrier liquid is less important than the leakage of the barrier liquid into the process fluid, the differential pressure can be relieved in other ways. That is, the pressure in the outlet chamber 94 is higher than the pressure in the impeller chamber 92.
Keep low by a few psi. In the circuit of FIG. 7, the two pressures are (automatically) compared and the difference is calculated using
At 84, the pressure in the outlet chamber is adjusted.

The pressure in the outlet chamber is generated by the action of a spiral groove (no external pressure source is provided) and, of course, the designer must take into account the viscosity of the barrier liquid, the rotational speed and the remaining parameters, It is necessary to make the pressure generating capability of the spiral groove appropriate. If the spiral groove can only supply a pressure of, for example, 60 psi and the process pressure rises to 100 psi (eg, while losing function), the seal 90
Will break.

Similarly, the lip seal 49 must not be subjected to pressures higher than a few psi, and again, the pressure regulator 69 controls the pressure in the inlet chamber. (As mentioned above, the pressure in the inlet chamber can also be controlled by aspirating the barrier liquid from a controlled head level.) If such precautions are taken, the barrier liquid Circulates in a circuit completely separate from the process fluid. The separated barrier liquid is filtered to control its temperature and other properties.

It can be seen that the barrier liquid supplied through the pipe 82 and circulating through the circuit is entirely liquid passing through the spiral groove. In the above design where the barrier liquid (externally pressurized) was circulating separately, such circulating was a bypass reference. In FIG. 9, all of the barrier liquid passing through the spiral groove enters the pipe 82 and is recirculated.

As mentioned above, elastomeric lip seals can be a few ps
can be replaced with a mechanical seal if such a lip seal is not good enough or if the lip seal is not suitable for other reasons.

FIG. 8 shows an example of a packing box having two mechanical seals 105 and 107. Seals are provided at each end of the pair of tapered sleeves, ie, tapered sleeves, with helical grooves formed on the outer surface of the inner rotor sleeve 109. Inner sleeve 109
Is keyed at 120 and the shaft 123
, And can slide along the shaft. Inlet and outlet chambers 125, 127
Are formed by an array of elements, and the pipe 12
8, 129 pass the barrier liquid through the chamber and the spiral groove.

The sleeve and seal shown in FIG. 8 includes a cartridge that can be formed as a convenient subassembly, which is an integral unit for fitting into the packing box housing 130. It turns out to be suitable.

FIG. 9 shows another structure using a mechanical seal. In this case, the tapered interface of the sleeve faces in the opposite direction, in this case the inner sleeve 132
One end of the mechanical seal 134 is accommodated by using a special space inside the end which is the thick end of the seal (ie, the right end in FIG. 9). This allows the total length of the seal and sleeve to be kept together at a minimum. As long as the pair of sleeves is counted as a journal bearing for the rotating shaft 135, the overhang of the shaft and impeller beyond the bearing is as short as possible. By providing the seal 134 inside the sleeve 132, the above-described overhang can be further reduced. It is not so important that the other mechanical seal 136 is short in the axial direction.

As shown in FIG. 9, another chamber 137 is connected to the inlet chamber 1.
47 can be provided outside. Using barrier liquid,
Lubricate the bearings 138 in the bearing housing. However, it is often not appropriate to do so, and FIG.
Is preferred.

The seal 139 is attached to a drive sleeve 140, which is fastened to the shaft 135 by a clamp screw 141. Drive teeth 142 are formed at the right end of the drive sleeve 140, and such drive teeth engage the corresponding drive slots of the inner sleeve 143.

A pair of tapered sleeves and seals combined
134 forms a first cartridge subassembly;
The subassembly is suitable for fitting into a housing 144. Drive sleeve 140 and seal 139 form another cartridge subassembly that is clamped to shaft 135 and bolted to housing 144 by cover 145.

Referring again to FIG. 7, FIG. 7 shows a circuit for supplying the barrier liquid to the inlet chamber 147 (FIG. 9) and for collecting the barrier liquid from the outlet chamber 149. As shown, the circuit is active (i.e., has no energy input) (except for providing energy to cool / heat the liquid). The pressure of the process fluid can be monitored and compared to the pressure in the outlet chamber, so that the seal 134 is not subjected to excessive differential pressure.

Circulating the barrier liquid between the sleeves and through the inlet and outlet chambers also serves to flush dirt and debris that may form in the chambers from the mechanical bearings. Ordinary mechanical seals are often provided with flash and drain equipment to remove foreign objects, and such equipment does not require the supply of energy and virtually nothing else is needed. Without being automatically provided in this case.

The inner sleeves 132 and 143 (FIGS. 9 and 10)
It can be seen that it slides freely on 5 axially, and that the spring 150 (FIG. 10) pushes the inner sleeve to the left (ie, goes deeper into the taper). However, the spring 15
The zero characteristic is basically selected based on the requirements of the mechanical seal 134. It may be necessary to tightly control the force pressing the tapered sleeves together over a narrow limit. The hydrodynamic film formed between the tapered surfaces is very robust. Once a film is formed between the bearing surfaces, increasing the force pressing such surfaces together has little effect in actually pressing such surfaces together, while the film is physically The force required to break apart and bring the surfaces into contact with each other is considerable. Therefore, the gap filled with the film between the tapered surfaces, even if the force pressing the surfaces to each other changes, or even set by the requirements of the mechanical seal,
To a large extent it is self-configuring and self-sustaining.

An axially movable sleeve 132 is provided in the outlet chamber 149.
And such pressure acts to push the sleeve 132 deeper into the taper, similar to the spring 150.

It has been described above that a pair of sleeves having a spiral groove play a role of a journal bearing for an impeller shaft. In the case of a conventional packing box type pump, one of the important factors in the calculations in determining the requirements of the shaft bearing (located in the bearing box 25) is that the impeller extends beyond the bearing. Overhang length. This overhang came to be encountered and also determined the period and amplitude of vibration that the bearing should accept. However, in this embodiment, the overhang is virtually zero (less than the diameter of the shaft). Thus, if the shaft bearing is formed by a sleeve that is very close to the impeller, the load on the bearing will be significantly less than the load normally applied to the pump bearing to be prepared for the overhanging shaft.

Therefore, this new design has a bearing housing (eg, 2
Not only does it eliminate the need for 5) and its need for lubrication, but it also significantly reduces the load and significantly reduces the need to use the bearings themselves.

Given that the bearings closest to the impeller can be typically 15 or 20 cm away from the impeller in a typical design, it is not difficult to make significant improvements in the design of the present invention. The designer should preferably move the bearing interface axially away from the impeller along the shaft, to within less than the diameter of the shaft.

Of course, the designer should ensure that the pump shaft withstands axial thrust, but outside the pump housing and between the pump housing and the coupling for such purpose (eg, 30). It is often convenient to provide a thrust bearing. (Couplings generally cannot transmit axial forces.) FIG. 11 shows a structure in which not only the bearing housing 25 has been removed, but also the coupling 30 between the motor shaft and the pump shaft has been removed. Is shown. The shaft 152 is the electric motor 1
It serves as both the armature 54 and the drive shaft of the pump impeller 156. The pump housing and the motor housing can be bolted together as a unit, and a precision machined spigot 158 serves to ensure alignment. Since there is no coupling, the axial thrust forces acting on the shaft are actually supported by thrust bearings 160 located in the motor housing.

FIG. 12 shows a pair of tapered sleeves arranged and combined in a seal / bearing configuration, in which case there is no penetrating shaft. The rotor 163 is formed as a stub.

The outer sleeve 164 is keyed at 165 to a stationary housing 167. The outer sleeve can float axially (vertically) within the housing,
Pressed upward by 167.

A spiral groove 169 is formed on the tapered surface of the rotor sleeve 163. When the sleeve 163 rotates, the action of the spiral groove pushes the barrier liquid supplied to the inlet chamber 170 downward toward the outlet chamber 172, and a hydrodynamic lubricating film is formed between the tapered surfaces.

The upper end of the inlet chamber 170 is sealed by a sealing interface 174 between the rotor sleeve and the stator sleeve. There is little pressure on the seal interface because the liquid in the inlet chamber 170 is aspirated into the inlet mouth of the spiral groove 169.

FIG. 13 shows a rotor sleeve 174 of the type used in the design described above. In the tests on the sleeve, the following performance was noted.

Male tapered sleeve No. 1 (contained in a flat female sleeve):-taper angle = 20 °;-diameter x = 47.6 mm;-diameter y = 31.8 mm;-length z = 44.4. mm;-Spiral groove = single, 2.03mm width x 0.20mm depth; groove pitch =
6.35mm (pitch between convolutions)-Land width between convolutions = 4.32mm Test 1:-Liquid = 18 ° C water (viscosity = 1.15 centistokes)-Rotational speed = 1750rpm Result: Generated pressure = 70psi flow rate Test 2: Liquid = 18 ° C water-Rotational speed = 3500 rpm Result: Generated pressure = 100 psi Flow rate = 4.5 L / hr. Test 3:-Liquid = water at 18 ° C-Rotational speed = 1100 rpm Result : Generation pressure = 40 psi Flow rate = 1.5 l / hr. Test 4:-Liquid = SAE 30 min, oil at 18 ° C, viscosity 50 centistokes-Rotation speed = 1750 rpm Result: Generation pressure = 300 psi Flow = 3.0 l / hr. Sleeve No. 2 (same as sleeve No. 1 except that the length z has been reduced to 38.0 mm by machining the narrow end) (into a flat female sleeve) Test 5:-Liquid = water at 18 ° C-Rotational speed = 1750 rpm Result: Generated pressure = 60 psi No. 3 (same as sleeve No. 1 except that the length z has been reduced to 31.6 mm by machining the narrow end) (in a flat female sleeve) Test 6:-Liquid = water at 18 ° C-Rotational speed = 1750 rpm Result: Generated pressure = 50 psi Sleeve No. 4 (forming two grooves with a pitch of 12.7 mm each,
Same as sleeve No. 1 except that the land width between adjacent convolutions is 4.32mm) (in a flat female sleeve) Test 7:-Liquid = 18 ° C water -Rotational speed = 1750 rpm Result: Generated pressure = 32 psi Flow rate = 5.4 l / hr. Test 8:-Liquid = water at 93 ° C (viscosity = 1.13 centistokes)-Rotary speed = 1750 rpm Result: Generated pressure = 64 psi Sleeve No.5 (Same as sleeve No. 1 except that it is a single groove and the depth of the groove is increased to 0.25 mm) (in a flat female sleeve) Test 9: − Liquid = Water at 18 ° C.-Rotational speed = 1750 rpm Result: Generated pressure = 60 psi Flow rate = 3.0 l / hr. Sleeve No. 6 (except that it is a single groove and the groove depth is increased to 0.30 mm) (Same as sleeve No. 1) (in a flat female sleeve) Test 10:-Liquid = water at 18 ° C-Rotational speed = 1750 rpm Result Generated pressure = 45 psi Flow rate = 4.5 l / hr. Sleeve No. 7 (same as sleeve No. 1 except that it is a single groove and the depth of the groove has been increased to 0.35 mm) (flat female Test 11:-Liquid = water at 18 ° C-Rotational speed = 1750 rpm Result: Generated pressure = 20psi Flow = 6.7 l / hr. Test 12:-Liquid = molasses at 18 ° C-Rotational speed = 1750 rpm Result: Generated pressure = 500 psi or greater Tests 1, 2, and 3 show a range of increasing rotational speeds that result in higher pressure and greater flow from the spiral groove.

Comparison of test 4 with test 1 shows that using oil rather than water as the liquid can produce significantly higher pressures.

Comparing Tests 5 and 6 with Test 1, the length is 6.4mm
Each reduction indicates that the resulting pressure drops by 10 psi.

Comparing Test 7 with Test 1, when two grooves are formed, the pressure is halved compared to the case of one groove,
The flow rate is shown to double.

Test 8 shows that when the water is almost boiling, the pressure obtained is reduced by approximately 8%.

Tests 9, 10, and 11 show that increasing the depth of the spiral groove reduces the pressure. About 0.50 when the liquid is water
Grooves deeper than mm do not produce any pressure.

Test 12 shows that if the liquid is molasses, a 0.50 mm deep groove will generate a pressure greater than 500 psi. However, when molasses is used, 0.30
Grooves shallower than mm have little effect on molasses.

The above test also shows that highly viscous liquids such as oil
This shows that compared to water, changes in speed, groove depth, and the like are considerably tolerated. However, it is clear that the grooves described above have a high performance in producing pressure and volume flow, even when the liquid is water.

In most cases, the requirement to create pressure in the barrier liquid in the packing box is to achieve high pressure. In fact, such a requirement is often that the barrier liquid is at a higher pressure than the process fluid.

In theory, as long as pressure is generated, no large volume flow is needed. In fact, large flow rates are disadvantageous, especially if the flow leaks into the process fluid.

However, when creating pressure in the barrier liquid in the packing box, the means for creating such pressure may be such that even if the barrier liquid is strongly circulated through the packing box, the sealing of the packing box may be It is important that the pressure be strong enough to be able to build such pressure, even in the event of a leak.

In this regard, one can consider attempts to create pressure using spiral markings, as shown in US Pat. No. 4,290,611. Such vortex markings can generate pressure only at zero or very low flow rates. Pressure is generated only during the absence of a leak. Thus, if for any reason a measurable amount of leakage begins to occur in the seal, the ability to generate pressure will be reduced and the seal will open immediately, permitting a large amount of leakage.

The above structure is not desirable. The mechanism for generating pressure must be versatile and robust enough to maintain the pressure of the barrier liquid, should the seal leak. If the seal between the process fluid and the packing box begins to leak slightly and the process fluid immediately enters the packing box, it is practically useless.

In the above-described design, such a desired degree of softness of pressure generation can be obtained. Properly setting the parameters such as the dimensions of the grooves for the rotation speed and the viscosity of the barrier liquid ensures that the barrier liquid exits the spiral groove exit marker reliably and continuously.

In most centrifugal pump installations, obtaining sufficient pressure from the spiral groove to overcome the pressure present in the process fluid is simple enough for the designer to use the spiral groove. Generates a flow rate of several liters per hour, the above-mentioned sufficient pressure can be obtained.

It has been found that this level of performance can be obtained even when the barrier liquid is water.

The designer needs the helical groove to be dimensioned correctly to obtain the desired pressure and flow rate.

The groove should not be deeper than about 0.4 mm, provided that the width is around 2 mm. Generally, the total or total cross-sectional area of the spiral groove (s) should not exceed about 1 square millimeter, and preferably does not exceed about 0.5 square millimeter.

The groove must not be too small. Small grooves can generate pressure, but cannot provide the proper volume flow at such pressure. The cross-sectional area of the groove is minimally about 0.3 square millimeters, below which in most cases the flow rate of the barrier liquid will be inadequate.

When the liquid is water, the groove has an area about twice as large as the area when the liquid is oil.

It can be seen that the spiral grooves described above can not only provide high pressures, but at the same time provide good flow rates at such pressures. This has not heretofore been achieved in pumps having packing boxes.

The volume of one convolution in the groove is typically about 0.05 milliliters, and if liquid flows from the outlet of the groove at a rate of 3 liters / hr (generally occurs), this means that
It can be calculated to provide about 0.03 milliliter of liquid per revolution, ie, about half the volume of one convolution of the groove per revolution.

The total length of the groove between the entry and exit mice is generally at least 50 cm or 70 cm. 30cm should be considered minimal. If the total length of the groove is too short, no pressure can be generated.

An important factor in using the present invention is the formation of a hydrodynamic film between the bearing surfaces. In order to make such a membrane robust and secure, the running gap or gap between the bearing surfaces should be small enough and the land between adjacent convolutions of the spiral groove should be wide enough. Should. It has been found that the width of the land between the convolutions is preferably 4 mm. 2 mm should be considered minimal.

As described herein, if the bearing surface is tapered and one tapered surface is formed in an axially moving sleeve, the designer may determine the gap between the surfaces that determines the thickness of the membrane. Can be very small. The smaller the gap and the wider the land, the greater the differential pressure that can be maintained between the convolutions of the groove.

The longer the spiral groove, the greater the final pressure obtained. Also, the longer the groove, the greater the resistance of the groove to reverse leakage and the greater the cross-sectional area of the groove without reducing the pressure at the outlet mouth, thus allowing a larger volume of liquid to flow along the groove You can see that it can be moved. The outer dimensions of typical packing box equipment are
The dimensions of the spiral groove that can be easily accommodated in it,
It will be appreciated that such a combination can produce more than a reasonable combination of pressure and volume flow through the groove.

The configuration of the spiral groove means that a very small amount of fluid can leak only through the groove, even if the mechanical seal breaks or the motor stops rotating. The grooves can have an area of one square millimeter and a length of 50 cm, and leakage through such grooves is necessarily slow.

As mentioned above, the designer must ensure that no leakage of process fluid occurs if the mechanical seal between the outlet chamber and the impeller chamber breaks (assuming the motor is running). Sometimes. In this case, the designer must adjust the pressure in the outlet chamber to be slightly higher than the pressure in the impeller chamber. As mentioned above, a pressure regulator is provided outside the housing of the packing box and is connected by pipes to both chambers.

The engineer adjusts the pressure in the outlet chamber,
It is necessary to automatically adjust the pressure to a value slightly higher than the pressure of the process fluid in the impeller chamber. This allows the engineer to have the barrier fluid flow from the outlet chamber into the impeller chamber, rather than the process fluid flowing from the impeller chamber into the outlet chamber, should the seal leak. As long as the pressure in the outlet chamber is maintained above the pressure of the process fluid, the process fluid will not leak out to the outlet chamber and thus to the outside.

Rather, the engineer, if more appropriate, can adjust the pressure in the outlet chamber to a pressure less than the pressure in the impeller chamber.
The main point in setting the pressure is that the pressure in the outlet chamber should be set to a value that does not differ significantly from high or low in the impeller chamber.

Similarly, the designer can maintain a small differential pressure across the mechanical seal between the inlet chamber and the outside. Next, a spiral groove extending between the inlet and outlet chambers takes the tip of the total pressure difference between the process fluid and atmospheric pressure. That is, the differential pressure before and after the seal is maintained at the minimum value by using the spiral groove. The lower the differential pressure across a mechanically contacting type seal, the longer the expected life of the seal.

The engineer adjusts the pressure in the outlet chamber,
The pressure can be slightly below or slightly above the process pressure. The pressure of the process fluid may be higher,
The differential pressure acting on the mechanical seal is small. This is, of course, not only good for the mechanical seal, but the high pressure in the outlet chamber also means a high interfacial pressure between the tapered surfaces, which means that the working bearing This is also good for the bearing surface as an interface.

If the pressure of the process fluid is high, i.e. higher than a few psi, even if the differential pressure acting on the seal is low,
Careful engineers choose mechanical seals rather than elastomeric lip seals for process chambers. Conversely, the seal between the inlet chamber and the external environment can often be safely provided with an elastomeric lip type. Mechanical seals are generally significantly more expensive than elastomeric lip seals.

The designer must ensure that the supply of barrier liquid to the mouth of the channel is not interrupted. However,
This is not a very strong requirement in a typical industrial pump environment. Furthermore, there is no need to pressurize the supply side of the barrier liquid. The reason for this is that the spiral groove will draw the barrier liquid from the (slight) vacuum (negative pressure) as needed.

The barrier liquid must be kept clean. If there is dirt between the tapered surfaces, such dirt will
Affects the function of the hydrodynamic membrane to properly maintain the gap between the tapered surfaces. However, it has been pointed out in the tests that the spiral groove itself on the tapered surface actually played a role in cleaning foreign particles from the tapered surface.

The reason for this self-cleaning function can be summed up by the fact that dirt particles tend to collect in the spiral grooves and not in the hydrodynamic membrane. Secondly, the velocity of the liquid moving along the groove has a tendency to flow dirt to the outlet end of the groove. The lands between the convolutions of the spiral grooves are narrow enough to allow the liquid of the film on these lands to enter the grooves. In this regard, the width of the land must not exceed about 8mm.

The choice of the material forming the rotor and stator sleeves is important. This is the case even if a hydrodynamic film is formed and, in theory, there is no contact between the bearing surfaces, because accidental contact necessarily occurs.

Elements having a surface with helical grooves should be formed of a harder material than elements with a flat surface. In that case, if any wear occurs, the flat surface will be worn and the groove will be kept intact. In fact, a small amount of wear is beneficial, because such wear provides a cushion between surfaces,
This is because the tightness of fitting is increased.

The right combination will fit a male rotor with grooves
It should be made of stainless steel coated with 0.1mm hard chrome, or made of ceramic bearing material. (Stainless steel without a coating, or coating, is not suitable because it tends to foul.) The flat female stator can be formed from carbon (graphite), PTFE, or one of (a number of) composite materials that have been developed to last a long time in contact with hard metals.

The designer must provide some means for pressing the tapered surfaces together. Such means are:
It can take the form of a mechanical spring, or it can provide the pressure of the barrier liquid or the pressure of the process fluid acting on a sleeve that can move axially to press the tapered surfaces together. (If there is no axial constraint, the tapered surface simply moves away and no hydrodynamic film is formed.)

When deciding how to provide the above means, the designer must consider whether leakage of the barrier liquid into the process fluid or leakage of the process fluid into the barrier liquid is the most important. Must. For example, when pumping beverage liquids, it is important that such beverage liquids are free of any barrier liquid, but if such beverage liquids are not harmful, a small amount of beverage liquid may be used. Leakage through the packing box is less of a problem. In other cases, the process fluid may be a harmful liquid, or may be a carcinogenic liquid with very little traces, in which case such harmful liquids may be packed. Preferably, it leaks into the box and is diluted with the barrier liquid.

The designer can use the pressure of the process fluid or the pressure of the barrier liquid as the primary factor for pressing the tapered surfaces together. Alternatively, the elements can be arranged such that the sleeve, which is movable with respect to one or both pressures, is neutral and its axial force is determined by a mechanical spring. Also, some suitable combinations of pressure exposure and mechanical springs can be made.

As the pressure of the barrier liquid increases, the hydrodynamic membrane increases its tendency to release the tapered surface. Therefore, it is generally preferred to push the axially movable sleeve more strongly into the taper as the process pressure increases.

If the resistance to detachment of the movable sleeve is too low, the pressure will not build up properly. Therefore,
The designer must make the axial force acting on the movable sleeve large enough to hold the tapered surfaces together, so that the desired pressure is created.

It does not matter much that the tapered surfaces are pressed together more than necessary, because the hydrodynamic membrane is very rigid. Conversely, the sleeve must not be so strong that the membrane actually breaks and the tapered surface makes mechanical contact. Even if the tapered surfaces acted together in such cases, tests have shown that forced contact between the tapered surfaces reduces the pressure in the outlet chamber.

The angle of the tapered part, that is, the taper angle is not too large,
Also, you must not be too small. The greater such an angle, the more force is needed to hold the tapered surfaces together and create pressure. If the force required to hold the sleeves together becomes too large to perform conveniently or to control conveniently, the angle will become too large.

Another problem arises when the taper angle is too large. As long as the tapered sleeve plays the role of a journal bearing for the impeller shaft, the bearing load acting on the tapered surface naturally induces an axial load between the tapered surfaces. This induced axial force tends to push the movable sleeve out of the taper.
The greater the taper angle, the greater the axial load induced to act on the movable sleeve. If such an angle is too large, means may be provided to resist axial movement of the movable sleeve to reduce the function of the movable sleeve to the most preferred position for forming a hydrodynamic membrane. It will be fixed. However, as long as the taper angle is not large, the aforementioned axial forces induced on the movable sleeve by the sleeve acting as a journal bearing are negligible.

Again, it should be pointed out that the overhang of the impeller extending beyond the sleeve is so short that the load on the journal bearing is small. The bearing load acting on the impeller can be reduced by balancing the outlet of the process fluid from the pump chamber. If the main bearing load is caused by vibrations due to long overhangs, the outlet pressure often cannot be balanced, but if the bearing is very close to the impeller, it will result from both the exit imbalance and vibration. The bearing forces can be reduced to very small values.

Based on the above considerations, it has been found that a taper angle between 10 ° and 30 ° (ie, a half angle between 5 ° and 15 °) gives good results, but the taper angle is 20 °. Preferably it is.

The maximum taper angle that can operate properly in accordance with the present invention is about 60 degrees. At angles greater than this value, the axial forces induced on the movable sleeve cannot be properly controlled.

Conversely, the taper angle must not be too small. If the taper angle is too small, it is difficult to manufacture the tapered surfaces in a state of being overlapped with each other. The reason is that the tapered surface tends to stick. The sticking also occurs when the tapered surfaces dry, thus increasing the coefficient of friction between the tapered surfaces. Therefore, the taper angle is
It is preferable that the angle is larger than the self-fixing angle. The self-fixing angle can be determined from the coefficient of friction between the two sleeves. For metals such as cast iron and bronze, the taper angle should be greater than about 7 °.

In the above design, the spiral groove is formed in the rotor sleeve, not in the stator sleeve, which is preferred. It is also preferred that the rotor sleeve is a male sleeve, the reason for which is that
This is because the grooves are formed on the outwardly facing surface and the inwardly facing surface can remain flat.

The helical groove may be formed in the tapered surface of the stator to make the tapered surface of the rotor flat. Also, the grooves can be formed in both the rotor and the stator.

In the present invention, the hydrodynamic membrane should be robust and secure. Unless the liquid has a very large lubricating property and viscosity, it is preferable to form the groove on only one of the tapered surfaces and leave the other tapered surface flat. The flat surface is preferably the surface of the stator, and the flat surface is preferably the surface of the female mold. If grooves are formed on both surfaces, the film tends to break. However, when the barrier liquid is dirty or may be dirty, and when the liquid is an oily liquid having an appropriate viscosity, it is preferable to form grooves on both surfaces.

As used herein, the expression "psi" is a unit of measure for fluid pressure. 1N / m ² = 1.4 in Sl unit (international unit)
5 × 10 ⁻⁴ psi.

Continuation of the front page (31) Priority claim number 9425594.0 (32) Priority date December 19, 1994 (December 19, 1994) (33) Priority claim country United Kingdom (GB) (31) Priority claim No. 9506195.8 (32) Priority date March 27, 1995 (March 27, 1995) (33) Priority country United Kingdom (GB) (56) References JP-A-58-146768 (JP, A) West German Patent Application Publication 3541816 (DE, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16J 15/40 F16J 15/447

Claims (39)

(57) [Claims] The invention comprises a stay multi-element (38) and a rotor element (36) adapted to rotate about an axis.
An apparatus for a rotating shaft (29), wherein said rotor and stator elements are formed with complementary shaped bearing surfaces (42, 43) provided coaxially around said axis. The bearing surfaces of the rotor and the stator are arranged to clean each other in a hydrodynamic bearing relationship over a region called a bearing region when the rotor rotates, and one of the bearings (43) is continuous. And a spiral groove extending along and around the bearing surface over the bearing area, wherein the spiral groove extends in the bearing surface. A plurality of convolutions extending over the helical grooves, the convolutions being arranged to leave a land having a substantial width between adjacent convolutions of the spiral groove; Spiral groove is the entrance mouse 47) and are configured to have an exit mouth (50), the apparatus has an inlet chamber (49) and the outlet chamber (5
2), wherein the chambers are configured to be in fluid communication with the inlet mouse and the outlet mouse, respectively, wherein the apparatus receives barrier liquid from a barrier liquid source and dispenses the barrier liquid. Means for transporting the barrier liquid to the outlet chamber, and means for transporting the barrier liquid away from the outlet chamber, the apparatus comprising: The apparatus is configured to flow from the inlet mouth to the outlet mouth along a spiral groove, and the apparatus is configured such that when the rotor rotates, the fitting of the bearing surfaces becomes a tight operation gap, and the gap between the bearing surfaces is formed. The gap or gap is sufficiently small and the width of the land between the convolutions is sufficiently large so that during rotation, there is a crevice between the bearing surfaces. Apparatus for rotating the shaft, characterized in that it is configured to drop dynamic film is continuously formed reliably. 2. Apparatus according to claim 1, wherein said complementary shaped bearing surfaces are fitted over each other in a male / female configuration over said bearing area. 3. The apparatus of claim 2, wherein said bearing surface is
An apparatus characterized by being formed in a conical taper shape. 4. Apparatus according to claim 3, wherein the apparatus includes means for guiding one of the rotor element and the stator element for axial movement relative to the other, and the tapered surface. Means for axially pressing said one element to press. 5. The apparatus of claim 1, wherein said apparatus is adapted to be mounted on a process fluid transport machine, said process fluid transport machine defining a process chamber containing a pressurized process fluid. An apparatus wherein the rotating shaft of the machine extends through the apparatus and the rotor and stator are configured to fit around the rotating shaft. 6. The apparatus according to claim 4, wherein said means for axially pressing said movable element is an area of said element, said area being the area on which said apparatus is mounted on said machine. When exposed to the pressure of the process fluid, the regions are configured such that, when the pressure of the process fluid increases, the force pressing the tapered surfaces together increases. An apparatus characterized in that: 7. The apparatus according to claim 4 or claim 5, wherein said means for axially pressing said movable element is an area of said element that is exposed to the pressure of a barrier liquid. Characteristic device. 8. Apparatus according to claim 4, wherein said means for axially pressing said movable element is a mechanical spring. 9. The device of claim 1, wherein said device comprises a first seal, said first seal being a type of rubbing said surface, said surface being resilient. Apparatus comprising means for pressing and rubbing against each other to make sealing contact, wherein the first seal is located at a location that seals and separates the inlet chamber from an external environment. 10. The device according to claim 5, wherein the device comprises a second seal, wherein the second seal is of a type that rubs the surface. The apparatus is provided in such a position that the outlet chamber is sealed off from the process chamber when the apparatus is mounted on the machine. 11. The apparatus of claim 10, wherein said first seal is a flexible lip-type seal and said second seal is a mechanical seal, said surface being of a relatively hard material. Devices elastically rub against each other. 12. The apparatus of claim 5, wherein the opportunity is a centrifugal pump having an impeller mounted on the shaft, the apparatus comprising a centrifugal pump wherein the bearing surface does not exceed the diameter of the shaft from the impeller. An apparatus characterized in that it is positioned with respect to said machine so as to be axially spaced. 13. The apparatus according to claim 4, wherein a taper angle between said tapered surfaces is between 7 ° and 30 °. 14. The apparatus according to claim 1, wherein said spiral groove continuously and regularly extends in a spiral manner over said bearing surface, without interruption, and is open at both ends. apparatus. 15. The apparatus according to claim 1, wherein said spiral groove is a single groove. 16. The apparatus of claim 1, wherein said spiral groove has a total length of at least 30 cm. 17. The apparatus of claim 1, wherein the width of the flat land between adjacent turns of the spiral groove is at least at least.
An apparatus characterized by being 2 mm. 18. The apparatus of claim 1, wherein the sum of the widths of all lands in said bearing area is at least half the average of all diameters of said bearing surface. 19. The apparatus of claim 1, wherein the cross-sectional area of the spiral groove is less than one square millimeter. 20. The device according to claim 1, wherein the cross-sectional area of the spiral groove is greater than 0.3 square millimeter. 21. The apparatus according to claim 1, wherein the spiral groove is provided in the rotor, and the surface of the stator is flat and has no groove. 22. The apparatus of claim 21, wherein said rotor is male. 23. The apparatus according to claim 1, wherein said apparatus comprises:
An apparatus, comprising: a pressure regulator, wherein the pressure regulator can regulate the pressure in the outlet chamber and the pressure in the inlet chamber. 24. Apparatus according to claim 5 or claim 23, wherein the apparatus comprises means for measuring the pressure of the process fluid, and wherein the pressure regulator controls the pressure in the outlet chamber. An apparatus characterized in that it can be adjusted to a proportional value close to the pressure. 25. The apparatus of claim 1, wherein said means for transporting said barrier liquid to said inlet chamber and said means for transporting said barrier liquid away from said outlet chamber comprise said outlet chamber. Wherein said barrier liquid is connected to said inlet chamber such that said barrier liquid circulates and recirculates said spiral groove. 26. A rotating shaft (29) having an impeller and mounted for rotation in a housing.
Assembly device for a stator element (3
8), and a rotor element (36) adapted to rotate about the axis of rotation of the shaft, wherein the stator element and the rotor element are arranged in the axial direction near the impeller. The rotor is annularly and coaxially mounted around and has complementary faces that are axially tapered to mate with one another in a male / female configuration, the rotor being co-located with the shaft. The stator is fixed for rotation, and the stator is fixed to the housing, and one of the complementary surfaces is formed with a continuous groove extending spirally around the surface. The helical groove has, at both axial ends, open entrance and exit mouths, and the complementary surface seals completely across the surface when the rotor rotates. Barrier flow for Is configured to form a tight operating gap so as to positively convey the fluid toward the impeller, and further receives a barrier fluid from a barrier fluid source and transmits the barrier fluid to the open portion of the spiral groove. A seal assembly device comprising means (56) for reliably transporting to an inlet mouse. 27. The seal assembly according to claim 26, wherein:
A seal assembly as claimed in claim 1, wherein said complementary surfaces are configured to clean each other in a hydrodynamic bearing relationship. 28. The seal assembly according to claim 26, wherein
A seal assembly, wherein the complementary groove is provided in a complementary surface of the rotor, and the complementary surface of the stator is flat and non-grooved. 29. The seal assembly according to claim 28, wherein
The seal assembly wherein the rotor is a male type. 30. The seal assembly according to claim 26, wherein
A seal assembly, wherein the axial taper angle of each of the complementary tapered surfaces is less than 30 °. 31. The seal assembly according to claim 26, wherein
One of the rotor and the stator is provided so as to move axially relative to the shaft, and further presses the one of the rotor and the stator axially toward the other, thereby And a mechanism for maintaining the complementary surface in a tight operating clearance relationship. 32. The seal assembly according to claim 31, wherein
The seal assembly wherein the mechanism is a mechanical spring. 33. The seal assembly according to claim 26, wherein
The seal assembly wherein the barrier fluid is water-based. 34. The seal assembly according to claim 26, wherein
The seal assembly of claim 1, wherein the barrier fluid is aspirated from the impeller process fluid. 35. The seal assembly according to claim 26, wherein
The seal assembly wherein the barrier fluid is separate from the process fluid under the action of the impeller. 36. The seal assembly according to claim 26, wherein
An outlet chamber is provided within the housing in fluid communication with the outlet mouth of the spiral groove, the outlet chamber receiving a barrier fluid discharged under pressure from the outlet mouth. Seal assembly. 37. The seal assembly according to claim 26, wherein
The seal assembly wherein the outlet chamber is separated from a process chamber in which the impeller is rotating by a seal subassembly. 38. The seal assembly according to claim 37, wherein
A seal assembly, comprising: a pressure regulator for regulating the pressure of the barrier fluid in the outlet chamber to a value proportional to the pressure of the process fluid in the process chamber. 39. The seal assembly of claim 38, wherein:
The seal assembly wherein the barrier fluid is water-based.