WO2003104688A1

WO2003104688A1 - Modular mechanical sealing system

Info

Publication number: WO2003104688A1
Application number: PCT/DE2002/002261
Authority: WO
Inventors: Jürgen Kästner
Original assignee: Köthener Spezialdichtungen GmbH
Priority date: 2002-06-10
Filing date: 2002-06-19
Publication date: 2003-12-18

Abstract

The invention relates to a cartridge-mounted mechanical sealing system, which is used to displace heavy media in machine installations and accommodates increasing demands in terms of centring and sealing, without the need for a cost-intensive replacement of pre-assembled models. In addition, further modifications permit the heat dissipation, e.g. in the vicinity of the O-ring that is subjected to higher temperatures, i.e. facing the media, to be improved and maintain the elasticity of the O-ring. A centring module (23) can be placed gradually on a base module by means of a hollow extensible shaft (5), equipped with a clamping cone. If the centring module is placed upside down, it fulfils an additional sealing function on a secondary side by the use of an additional O-ring and a radial shaft seal ring (13). Finally, the modifiable centring device (23) can be replaced by a complete individual seal, which in addition is equipped with a sinusoidal spring (18) consisting of elastic spring steel. Said sinusoidal spring can be selectively integrated into the clamping cone combinations that can exist on the primary side or secondary side.

Description

Modulgleitringdichtungssystem

The invention relates to a mechanical seal system in single and cartridge-mounted construction, which is used in mechanical engineering systems for moving or conveying highly viscous media and takes into account increasing requirements with regard to centering, quenching and double sealing without the cost-intensive replacement of pre-assembled designs to have to make. The heat dissipation z. B. in the area of the corresponding temperature, d. H. Media-facing, improved O-ring and supports the maintenance of the elasticity of the O-ring.

Following the state of the art, there are solutions that follow in the literature

A distinction is made between basic types:

Mechanical seal with group or individual springs, which are arranged in the product space and thus work in the same direction as the pressure gradient. Mechanical seal with group or individual springs, which are arranged outside the product area and thus work protected from the medium. However, their contact pressure must be built up against the acting pressure gradient.

The above Basic versions are known in single or cartridge-mounted construction.

Your application can be used as a single-acting mechanical seal, as a quenched

Mechanical seal or as a double-acting mechanical seal.

A disadvantage of all principle solutions is the assignment to one of the above

Spring arrangements in the stationary or rotating part.

The advantages of the unused spring arrangement are therefore always given up and

Disadvantages of the spring arrangement used accepted.

This dichotomy in the mechanical seal philosophy has led to more in the past

A multitude of different solutions, the assignment of which for optimal application tasks is becoming ever more complicated by the user. The cartridge-mounted mechanical seals are increasingly taking a special place in modern sealing technology.

Unfortunately, the costs and the size of the building often increase enormously with the expansion. The large overall length can lead to tilting of the slide rings when the drive shaft is loaded and thus to failure of the seal.

Another disadvantage must be seen in the narrow guides of the slide rings, which limits their mobility.

Only complex special constructions, such as those offered by the companies AES and GLE in the form of a movable counter ring, can solve the problem. Another disadvantage of all mechanical seals is the positive communication between the mechanical seal and rotating parts.

As a result, vibrations and shocks are increasingly transmitted from the drive shaft to the slide rings. In the case of strongly adhesive media and frequent start-up and shutdown processes, this can destroy the slide rings or the form-locking elements.

Another disadvantage of quenched or double-acting mechanical seals, especially in a compact cartridge design, is that the quench or barrier liquid is not optimally brought up to the sliding surface to be cooled in every case. Elaborate pump systems, e.g. from GLE, provide a solution, but lead to high costs and a further increase in size.

According to DE-OS 37 00 888 AI a mechanical seal for sealing an axis rotating with respect to a wall is proposed, the sliding and sealing ring on their contact surfaces, in particular by means of shrinkage via a convex shape of the sliding or sealing ring, even in the event of temperature fluctuations, a permanent radial and realize axial support. However, it remains to be seen whether the selected arrangement is also suitable, jerky start-up processes in stiff media (bitumen, sugar solutions, etc.) and sometimes slight deflections of the rotating ones Intercept elements elastically. The cooling problems due to the indicated operating conditions will not be discussed further.

With the disadvantages described, the known state of the mechanical seal systems cannot satisfy.

The invention is therefore based on the object of offering a solution with which only a small increase in size with increasing demands on the sealing problem is possible, by using existing basic patterns without complete replacement, increasing the service life of the mechanical seal, particularly under the influence of high temperatures of the medium in question is by using a Redundanzanfederung and an integrated pumping ^mechanism, which conveys the cooling liquid optimal in the areas of high temperature and by a specially designed clamping cone system that completely dispensed even at very high peripheral speeds on form-fitting drive elements and if necessary. momentary "slippage" the O-ring between the hollow shaft and slide ring can be restored very quickly thanks to the special bearing design of the sinus spring, the combined positive / frictional entrainment.

According to the invention the object is achieved as follows, reference being made to claim 1 with regard to the basic inventive ideas. The further embodiment of the invention results from claims 2 to 11.

Further explanations are to follow regarding the solution according to the invention.

The modular mechanical seal system gradually builds up from a basic module, which has a new clamping cone combination with O-rings, to a double seal module, whereby ultimately primary, ie media-side and secondary, ie atmospheric, comprehensive protection against escaping medium is achieved. The basic module, consisting of a clamping cone, which is located on a hollow stub shaft, an O-ring, slide ring and counter ring, the latter being supported on the housing flange via an additional O-ring, receives one on the secondary side via the extendable hollow stub shaft centering unit supporting the shaft alignment, the centering module. In its design, it encloses the centering and pumping ring already integrated in the basic module and has a stabilizing effect on radial shaft movements. The centering and pumping ring itself has several spiral, curved "teeth" on its inner diameter, so that during quench or sealing water operation, due to its rotation, the coolant is swirled in the direction of the primary cone combination, which is indicated by a large spiral spring the hollow stub shaft is supported with regard to the desired directional transport.

Already in this training it can be seen that no positive entrainment elements are used and that the torsional moments are transmitted in full via the single or double arranged cone combinations arranged in the basic module by means of the O-rings made of elastomers.

In a second stage, the system used up to this point to increase the secondary sealing effect by adapting the hollow stub shaft to new components to be added is expanded in such a way that the two-part hollow stub shaft telescopes into a next existing detent, which is located on its inner diameter of the smaller part , pulled and fixed again using countersunk grub screws. This makes it possible to place the existing centering module in the opposite direction in the direction of the media-facing side, to embed an O-ring in an existing groove in the centering module and to arrange a radial shaft seal in the outward-facing closure of the centering module to further perfect the seal. The extension of the hollow stub shaft is taken into account by a spacer ring to secure the "Inner" stability is pushed onto the end of the hollow stub shaft. This constructive training is also suitable for pressureless quenching.

Finally, in a third stage, while maintaining most of the components that have already been used, a fully developed clamping cone combination can also be produced on the secondary side, in the form of an inverted individual seal. In this case, the combination with the radial shaft seal described above is replaced by a stationary slide ring. The slight expansion of the module is also followed here with the readjustment of the hollow stub shaft, whereby several spacer rings are used. An extremely useful effect for maintaining the possibly decreasing elasticity of the O-rings transmitting the torsional moments is achieved by a sine spring supported against the O-ring and sliding ring made of elastic spring steel. To protect the slide ring, which may have a silicon alloy and is therefore insensitive to pressure against the selective contact of the sinus spring, there is a support ring in front of the slide ring, which also ensures cheaper, flat force transmission.

With this 3rd stage, the problems of centering and sealing with regard to recognizably grown requirements are solved in a compact design at the highest level, without having to replace existing or apparently unsuitable elements, the power transmission of the torsional moments even at higher temperatures and non-destructively, in the event of any jerky start of the units can take place.

To quickly overcome any "permanent slip" of the O-ring that may occur at high speeds or overload, the contact surfaces of the hollow stub shaft and slide ring for the sinus spring each have at least 3 incorporated recesses with oblique outlets on both sides. The prestressed .sine spring rests in the recesses starting position. In this installation situation, the overall system takes over the transmission of the torques up to a point at which the overload and / or high speeds

There is a risk that the static friction forces on the O-ring located between the hollow stub shaft and slide ring will decrease. As a result of the associated spring deformation, the

Sinus spring their installation position on the contact surfaces of the sliding and sealing ring or

Hollow stub shaft.

This can be done several times, with a "breakaway effect" associated therewith, the static friction of the system is regained in a short time via the O-ring.

This gives the module mechanical seal system the technical prerequisite with higher

Speeds and higher forces in extreme situations.

The invention will be explained in more detail below with the aid of exemplary embodiments. The following representations are used:

Figure 1: Sectional view of the basic module

Figure 2: Sectional view of the basic module with centering module

Figure 3: Sectional view with rotated centering module and radial shaft seal

Figure 4: Sectional view of the basic module combined with a rotated individual seal

Figure 5: Sectional view of the individual seal (overview)

Figure 6: Sealing system in a sectional view with sinus spring mounted in recesses

The reference symbols used in detail have the following meanings:

1 - clamping cone 14 - grub screw

2 - slide ring 15 - spacer ring 3 - O-ring 16 - O-ring

4 - counter ring 17 - spacer ring

5 - hollow stub shaft 18 - sine spring

6 - Housing flange 19 - O-ring

7 - O-ring 20 - O-ring

8 - coolant supply 21 - slide ring

9 - centering and pumping ring 22 - support ring

10 - compression spring 23 - centering module

11 - detents 24 - collar 12 - O-ring 25 - collar

13 - radial shaft sealing ring 26 - recess

27 - sloping spout

A basic module as a basic version contains a tensioning cone combination, consisting essentially of the tensioning cone 1 worked up on a hollow stub shaft 5, the slide ring 2 and the O-ring 3.

In a continuation of a modular design, a centering module 23 is pushed onto the hollow stub shaft 5 on the secondary side for centering the shafts and housing, the collar 24 pointing in the direction of the housing flange 6 enclosing the centering and pumping ring 9, which in turn is in operative contact with the compression spring 10.

In continuation of the modular design, the compression spring 10 is pushed against the slide ring 2. This takes on the function of a redundancy spring for the primary cone system described above. It closes on the centering module 23 with centering and

Pump ring 9, which is pushed onto the hollow stub shaft 5, the centering between the base module

Hollow shaft 5 and housing ensures. On the circumference of the inner part of the hollow stub shaft 5 there are detents 11 in a double-ring offset arrangement which by means of grub screws 14 that can be screwed into them for fixing the telescopically expandable hollow stub shaft 5.

This occurs when, to improve the secondary side (atmosphere side)

Sealing effect further measures are to be taken and the hollow stub shaft 5 is to be fixed slightly apart in a next detent 11. The above remains

Centering module 23 obtained as a component, but in a rotated arrangement, with the O-ring 12 in a prepared groove and in the collar 24 which now points outwards

Centering module 23 of the radial shaft sealing ring 13 is placed.

Likewise, an O-ring 20 for sealing the hollow stub shaft 5 into the one prepared for it

Groove placed. The slightly increased size on the secondary side is taken into account insofar as the spacer ring 15 is used for bridging inside the hollow stub shaft 5.

Within this module version, the centering and pumping ring 9 takes over the task which is carried out in the

To direct entrained liquid inside the housing in an axial direction via the rotation of the hollow stub shaft 5. The design of the centering and pumping ring 9 is to be carried out in such a way that its smallest possible diameter is curved by at least 3

"Gears" the outer diameter of the hollow stub shaft 5 in the rear area and the largest that of the curved "gears" with respect to the inner diameter of the compression spring

10 corresponds. Furthermore, these curved "gears" should be in the direction of rotation

Mechanical seal should be executed, a material with good sliding properties and low hardness compared to that of the hollow stub shaft 5 should be used.

With regard to the liquid transport, this concern is supported by the compression spring 10, which in this special arrangement is a kind of “Archimedean

Water snail "acts.

This makes it possible to avoid a contact flow between the quench inlet and outlet and thus direct the quench liquid directly to the heat-producing sliding surface. If the sealing problem is to be assigned an even higher priority, a complete individual seal, according to FIG. 5, is provided on the secondary side and again as a special feature for maintaining the "internal tension" in the hollow stub shaft 5 - omitting the centering module 23 used up to this point two combined clamping cone combinations, for example in front of the secondary side, an annular, wavy sinus spring 18 is embedded. This measure compensates for the elasticity of the "resilient" O-ring 19 which inevitably decreases at higher temperatures.

When using the tensioning cone combinations mentioned several times, care should be taken that the larger tensioning cone angle is placed directly on the hollow stub shaft 5 and the smaller one is incorporated in the interior of the slide ring 2.

The already mentioned O-rings 16, 20 and the spacer rings 17 are also provided for this embodiment.

In the case of a silicon slide ring 21, a support ring 22 is used between the latter and the sine spring 18 to avoid mechanical damage.

According to a further embodiment according to FIG. 6, in the hollow stub shaft 5 and the sliding ring 2 there are alternately preferably 3 or, depending on the existing corrugations of the sinus spring 18, also further depressions 26 with oblique outlets 27. These serve the sinus spring 18 as a starting position, whereby an exit can only take place in the event of overload and / or higher speeds and subsequently slides into the next depressions 26.

Providing the contact surfaces of the slide ring 2 and the hollow stub shaft 5 with the recesses 26 and inclined outlets 27 has the advantage that the module mechanical seal system does not fail in stiff media and when stuck, but - without disassembly and expensive maintenance work - automatically, by realizing a "breakaway effect" , regained its function in the sense of a combined form-fit / force-fit entrainment. The advantages of the invention can be summarized as follows:

1. A stub shaft system allows a modular "upgrade".

2. Integration of two spring systems that act independently of one another, which means that mechanical seals made of elastomeric materials are used over a longer period than before

3. existing O-rings are operational and the advantages of both spring arrangement principles, material spring 1, 2, 3 in the rotating part and compression spring 10 in the stationary part, can be used.

4. Unpressurized quench operation or pressurized sealing water operation with a high cooling effect by means of expedient and multifunctional "control elements", such as centering and pump ring 9 and compression spring 10 (effect as "Archimedean water screw").

5. Shock-damped transmission of the torsional moments even when the units start up abruptly, whereby the usual spring (screw) / pin pairs in the primary area of known mechanical seals are dispensed with, and thus positive connections cannot be destroyed.

6. The special design of the contact surfaces on the slide ring 2 and the hollow stub shaft 5 for the sine spring 18 ensures the rapid restoration of the combined form-fit / force-fit entrainment via the O-ring 3.

Claims

claims

1. Module mechanical seal system, consisting of known components, namely clamping cone (1), slide ring (2), O-ring (3) and Quencl supply (8), characterized in that the centering module (23) with two different collars (24, 25) can be variably placed on the telescopic, expandable hollow stub shaft (5) and is always connected to a centering and pumping ring (9) and the compression spring (10).

2. Module mechanical seal system according to claim 1, characterized in that the centering module (23) by a complete individual seal, consisting of a clamping cone combination with O-rings (16, 19), slide ring (21) while maintaining the centering and pump ring (9) and Compression spring (10) can be used and the sine spring (18) is also in contact with the slide ring (21) via the support ring (22).

3. Module mechanical seal system according to claim 1 and 2, characterized in that the hollow stub shaft (5) has double ring-shaped, staggered detents (11), in which in the outer part of the hollow stub shaft (5) screw-in and retractable grub screws (14) engage.

4. Module mechanical seal system according to claim 1 and 3, characterized in that spacer rings (15, 17) are used in the interior of the hollow stub shaft (5).

5. Module mechanical seal system according to claim 1, characterized in that in the centering module (23) another O-ring (12) and the radial shaft seal (13) are used.

6. Module mechanical seal system according to claim 1 and 5, characterized in that work is carried out with pressureless or pressurized coolant, introduced via the coolant supply (8).

7. Module mechanical seal system according to claim 1 and 2, characterized in that the larger clamping cone angle is placed directly on the hollow stub shaft (5) and the smaller one is incorporated in the interior of the slide ring (2).

8. Module mechanical seal system according to claim 1, characterized in that the smallest diameter of a centering and pumping ring (9) of at least 3 curved teeth the outer diameter of the hollow stub shaft (5) in the rear region and the largest diameter of the curved teeth the inner diameter of the compression spring (10) corresponds.

9. Module mechanical seal system according to claim lund 8, characterized in that the curved teeth are designed in the direction of rotation of the mechanical seal and a material with good sliding properties and low hardness compared to that of the hollow stub shaft (5) is used.

10. Module mechanical seal system according to claim 1, characterized in that in the basic version of the counter ring (4) between the slide ring (2) and the housing flange (6) is arranged.

11. Module mechanical seal system according to claim 1, characterized in that in the bearing surfaces of the sine spring (18) on the slide ring (2) and the hollow stub shaft (5), the recesses (26) with their oblique outlets (27) are introduced.