DE2113703A1 - Seal, in particular a mechanical seal, preferably for use in refrigerant compressors - Google Patents

Description

Seal, in particular mechanical seal, preferably for use in refrigerant compressors.

The invention relates to a seal, in particular a mechanical seal, preferably for use in Refrigerant compressors for sealing a gap between zv / egg machine parts, such as B. a shaft that is surrounded by a housing and passed through it, with a non-rotatable and tight on one machine part held but axially displaceable thrust ring, one with the other machine part circumferential and axially displaceable sliding ring, against which one is under spring force Secondary seal with the machine part is assigned circumferentially, but axially displaceable.

It is known that at the points of passage of shafts or axles through this machine part, one or Use an enclosing housing to prevent the escape of a fluid, sealing elements for some years now, the known mechanical seals have been increasingly preferred

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have »The problems and difficulties that arise to prevent leakage at the passage and sealing points, which in turn result from - ··. - the requirements placed on the respective seal and the operating conditions , as- s. · .. B. flow media, pressure conditions., axial and radial movements as well as surface quality of the V / elle, the size of the contact area and thus the. Wrinkled, that a hardly overlookable amount of the most diverse types of sealing elements in the form of mechanical seals have become known, whereby these mechanical seals are mainly used for liquid media, whereas these seal elements are used with success when using such sealing elements Sealing of slightly liquefied gases such as the refrigerant in refrigeration compressors, inconsistently greater difficulties arise and an unsatisfactory solution is found, unless these difficulties are eliminated or reduced by a relatively large effort the sealing of refrigerant compressors due to the extremely large pressure difference, since a perfect function of the seal is required both under vacuum and at high pressures and thus the reversal of the nuisance makes special measures necessary. In a * mechanical seal of the type described above for sealing 'parts against high pressures, it is known that the secondary seal consisting of two known elastic roof-shaped sealing rings connected in series is constructed in such a way that the tree between these two rings is connected to the one in the sliding surface through a pressure compensation line Annular groove space is in connection, whereby the

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"Binding by means of the axially displaceable sliding ring directed channel is established. To ensure the tightness this seal requires for the maintenance of a controllable pressure A complicated overall construction of the mechanical seals is disadvantageous in the space between the packings is called this constructive version that the establishment is complex and thus requires a relatively long tree further specialist part insofar as the distance to the camp becomes relatively large for the volume to be sealed and thus gives the skins a restless run. This in turn has a detrimental effect on the desired tightness the seal itself. Furthermore, this version is only suitable for one-sided flow and only reliable in a very narrow pressure range.

In a further known mechanical seal of the type mentioned above, the inner or outer circumference is a sealing ring with an incised deep circumferential ring groove towards the side of the higher pressure provided in such a way that the 'tfand formed between the circumferential ring groove and the sliding surface in the axial Able to bend pressurization, the circumferential ring groove via channels with in the sliding surface one of the sealing rings incised hanging groove is in connection. Even if this mechanical seal is suitable for a larger pressure range and pressure fluctuations, so is this seal also suffered from the aforementioned disadvantages overall.

In particular, however, both mechanical seals have the common disadvantage that they are

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precautions are not suitable because "in the case of vacuum the Open sealing surfaces and thus the desired Destroy the sealing effect

Furthermore, a mechanical seal is "known" in the a rotationally secured and axially displaceable slide ring has a sleeve-shaped extension that with an annular chamber surrounding the shaft forms a housing part closing off the extension, the chamber having a spring-loaded secondary sealing device receives the two formed as a wedge-shaped sealing rings, opposite each other arranged individual seals, in their jointly formed opening angle a from the housing cover protruding wedge-shaped pressure piece engages

The disadvantage of this mechanical seal is that the split sealing rings have four leakage paths and thus impair the security of the seal.

There is a risk of leakage as soon as the sealing surfaces do not seal both as a whole and at the same time. The above-mentioned disadvantages also appear more or less here or are applicable

Furthermore, a mechanical seal is known, in particular for sealing against gases, in which several mutually mutually axially movable sliding rings are sealed against each other and the mutually facing surfaces of two adjacent rings and their common opposing surface delimit a gap-shaped space filled with lubricant, with several for the radial seal Round rings are used. To regulate the Druokver-

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ratios are the sliding rings with annular duct openings provided with the lubricant spaces Establish a connection · It is evident »that this mechanical seal The use of round rings is particularly disadvantageous, since they on the one hand only seal radially, on the other hand the O-rings do not guarantee any tightness against light liquefied gases, since the press seam required by the production is not with such precision can be removed so that a secure seal can be achieved »

To avoid these defects, seals in the form of groove, expanding or lip sealing rings are known, which according to their property due to the structural design as well as the actual Sealing element as well as secondary sealing use Find·

So is z. B. known an expanding ring, the lip parts Experience an elongation through a recess in the back part and thus the spreading apart make the lips much easier, with a round ring being used as a spreading means. This kind of Seals only allow a one-way flow and are therefore used as a sealing element for reciprocal Pressure not suitable.

Furthermore, designed as a lip ring seal with parallel circumferential surfaces is known in which Opening angle a tongue-shaped support ring engages In this embodiment, too, tightness is only guaranteed in one flow direction. Even the Axial movements of the shaft no longer allow the sealing lip to function properly, as the front

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tension of the lips of the applied to the shaft Seal a sticking of the lip bar and thus the axial movements of the Yfelle are not inertia follows.

Furthermore, a lip ring is known, the lip length of which is formed by the opening angle through a groove is enlarged in the back and the Urafangsflr-ohen have an angled kink such that the cross-sectional area has a double trapezoidal shape assumes, where the 7 / inkel is greater than 180 ° and is at the level of the deepest ITut incision, so that the lip parts show a spread, which makes up the preload when installed * Sin in The tongue-shaped pressure ring engaging in the middle of the groove only causes the elastic ones to be displaced Mass in the back part of the lip ring »A dimple effect on the lip parts occurs not »When using a wedge-shaped pressure ring the pressure on the lip parts is increased, pressure fluctuations and even axial relative movements the shaft reacts very slowly to the application, so that the tightness is no longer guaranteed if j this sealing element is suitable as a “secondary seal for mechanical seals also not with load reversals

The purpose of the invention is to overcome the aforementioned disadvantages and to eliminate defects, in particular to design the sealing unit so that an absolute technical tightness of the sealing elements. for one larger area of application is guaranteed.

The invention is based on the object of a sliding

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ring seal rait secondary seal in relatively simple To create a design that "both at high pressures and in a vacuum with a residual pressure of less than 2 Torr works without problems, especially a sealing of slightly liquefied gases, for Example when used in refrigerant compressors, guaranteed »

According to the invention, the object is achieved in that which in a manner known per se from one of the highly polymeric Secondary seal formed from the material consisting of a U-ring in one of the sliding rings encompassing annular bandage one behind the other and supporting one another, is embedded in an axially sliding manner, so that the Primary seal with the secondary seal on the v / el form a common axial sealing sequence and that the cross-sectional profile axis center of the groove ring and the Axial center of the cross-sectional profile of a spring-loaded pressure ring acting in its opening angle on a single axis with the same axis center diameter or the axes are staggered with different sized axis center diameters, wherein the cross-sectional profiles of the rings are designed symmetrically and / or asymmetrically, so that the inner lip part when pressure is applied to the outer lip part of the U-ring against the shaft is elastically pressed

In a modified form, the invention provides that the ring-shaped bandage for receiving the secondary seal is incorporated into the sliding ring

According to the invention, the U-ring to achieve the "elasticity and maintenance of stability in one

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split trapezoidal cross-sectional geometry, the is formed from a spreading of the lip parts angled towards the end faces, wherein an angular subdivision is provided in the lateral surfaces, the angle of which is less than 180 ° "is so that the lip parts in the installed state a the sealing surfaces have sealing, but still slidable gate tension and that the opening angle of the groove ring is smaller than the pressure angle of the pressure ring «.

The embedding of the secondary seal in the annular Bandage, which is both designed as an independent component and incorporated into the sliding ring can be, the mechanical seal is designed as a simple uncomplicated unit with one behind the other, in the manufacture of relatively simple sealing rings, which have a joint on the shaft to be sealed Form axial sealing sequence and their exclusively radial Gleitfläohen relatively easy by appropriate Spring loading are to be mastered. The axial offset of the secondary seal has a supporting effect in the case of symmetrical cross-sectional profiles compared to the Druokring or with different cross-sectional profiles in connection with the resulting one-sided loading of the outer lip part and the design of the U-ring, as a result it is guaranteed that with axial relative movements of the V / elle to the sealing part the sealing ring slides so that that he reacts without inertia and thus no moment the sealing contact between the slip rings and the V / el is lost. This ensures that the mechanical seal at both high and low Drüoken as well as reversing loads, even with slightly liquefied gases, works flawlessly and offers absolutely technical tightness

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The invention is to be - hereinafter based on an exemplary embodiment are explained in more detail in the drawing show:

Fig. 1: an axial section of an inventive double acting mechanical seal 5

Fig, 2: a cross-sonity representation of a relieved Secondary gate installation;

Fig. 3: a cross-sectional view of a "loaded Secondary insulation when installed;

Fig. 4: a cross-sectional representation of an asymmetrical one Pressure ring and a symmetrical groove ring with common Aohsen;

Fig. 5: a cross-sonity representation of a symmetrical Druokring and an asymmetrical one U-ring with common axis 5

6: a cross-sectional view of a pressure ring and a pressure ring with an asymmetrical design on a common axis. The mechanical seal in Fig. 1 is double-acting and sits on the intercepted by the bearing 26 shaft 2 in the of. a housing surrounded sliding ring space 16, which is closed with the cover · On the housing side, the angular stop ring 3 ^{1 is} in the housing. 1 used, to which an O-ring 13 'is associated with a seal. Both sealing elements are pressed against rotation in the housing 1, the axial leg of the thrust ring being let in freely movable in the housing part and the radial leg being held by the circular ring at a distance from the housing wall, "This is achieved by the radial legs on the Gahäuseseite by Kinßteohen has an approach. On the fixed outer Gc henke Ie el te the Gleltring 4 ^{1 runs} around *, represent

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with the secondary elastic 6 * is embedded in the ring-shaped bandage 5 * »Sin driver 12 connects the bandage 5 ¹ with the spring cage 9 through the rivet 15. The bolt 1o, which is embedded in a shaft groove 14, locks the spring cage 9 rotationally fixed to the shaft 2, the bolt being gesiohört 10 with an I clamping ring 11 * Multiple distributed over the periphery of the shaft 2 guided in the spring cage 9 pressure springs 8 push the pressure ring 7 * against the Nütring 6 * * It is understood * that instead the compression springs 8 also a single large helical spring (not shown in the drawing) encompassing the shaft 2 can be inserted.

In Fig. 2, the groove ring 6 ¹ is shown clearly before it is built into the mechanical seal, the parts forming the sealing space, such as the bandage 5% sliding ring 4 * and shaft 2, are shown only schematically, so that the cross-sectional geometry of the liutring 6 · particularly is highlighted. The IJutring 6 'has a trapezoidal design in its base body, the axial sealing surfaces 22; 23 formed lateral surfaces again receive an "angular subdivision, the included Y / angle oC is less than 180 °.

The position of the lateral surfaces angled towards the end faces results in the spreading of the lip parts,, whose inner and outer oversize the pretensioning · This ensures that the sealing

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Lips in the .Sealing chamber from the outset are in good contact with the surfaces to be sealed in the installed state Fig. 3 · The dimensioning of the lip parts is kept in such a way that the seal ring 6 ^{1 maintains} its internal rigidity, but has the greatest possible elasticity. These niigenscnaften are important in that on the one hand there is no twisting of the hat ring 6 ¹ and thus makes it inoperative and on the other hand the hat ring 6 ^{1 is} so elastic that it reacts immediately to any change in pressure.

The opening angle forming the sealing surfaces 18 and 2o is selected to be ^{smaller in the l.utring 6 f} than the V / inKeI of the wedge-shaped pressure ring 7 '»whose center 25 of the diaphragm 6' is offset, thus the center diameter of the imtring, 'greater than the was held by the uutring 6 ^f . With this arrangement, the pressure is applied to the outer lip part 29 of the lip ring 6 ^f , which, when pressed against the bandage 5 ^1, derives the pressure through an annular displacement on the inner lip part in a reduced form, so that the inner lip part 28 due to its elasticity both with every change in pressure and with axial helative movements of the / skin to the sealing part so that it reacts inertially and does not lose a moment of the thinning contact between the sliding rings. By the annular mass shift is maintained both "of the inner lip portion 28 elastically as a leak-free sealed the four leak paths. The gleicne effect is achieved with a common axis of iJutring 6 and the thrust collar 7 when the Querschniütsprofile of the two hinge 6y 7 in Fig, 4} 5 and 6 are designed symmetrically and / or asymmetrically.

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The arrangement of the individual Diohteleraente, their Shaping and the design of the mechanical seal with the secondary sealing enables an absolute technical sealing

It works trouble-free at both high and low pressures and also seals when the load is reversed sioher, even with yakuum with a residual pressure of less than two torr in aggregates with lent liquefied gases as working medium.

The mechanical seal is simple as well as double-acting due to its uncomplicated structure usable, whereby the groove ring provided as a secondary seal can also be used for other sealing purposes can be used

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Claims (1)

Claims Λ · Seal, in particular a mechanical seal, preferably for use in refrigerant pressure compressors, to seal a gap between two machine parts, such as a part surrounded by a housing, with a thrust ring that is held elastically tightly against one machine part, one with the other machine part rotating and axially movable sliding ring against which a spring-loaded secondary seal is pressed circumferentially but axially displaceably with the machine part, characterized in that the secondary seal formed in a manner known per se from an elastic material made of elastic material in a secondary seal the sliding ring (4) with a comprehensive ring-shaped bandage (5) one behind the other and supporting one another, but is embedded in an axially sliding manner, and the diaphragm elements of the primary seal with the secondary diaphragm on the vane (2) are arranged to form a common axial diaphragm sequence and that the cross-sectional profile Laehsmitte (29) of the grooved ring (6) and the Aohsraitte (24) of the transverse Sonittprofiles of a spring-loaded Druokrin gps (7) acting in its opening angle on a common axis with the same Aohsmitte- diameter or the Aohsen (24; 2?) Are set offset with different sized Aohsmittendurohmesser, the Quersohnittprofile of the rings (6 j 7) are designed symmetrically and / or asymmetrically, so that the inner Idppteil (28) "at -2- 1 0 9 8 S 1/0 9 U a Druokbeaufsohlagung on the outer Idppteil (29) against the shaft (2) elastic is indicated. 2 «seal according to claim 1, characterized in that that the annular bandage (5) incorporated into the sliding ring (4) for receiving the secondary seal is, 3e seal, consisting of an elastic groove ring and a pressure ring, preferably for use as a secondary seal in sliding ring seals, thereby characterized in that in order to achieve elasticity while maintaining the stability of the U-ring (6) is divided into a trapezoidal cross-sectional geometry, which consists of a die'Mantelflächen zu the end faces angled spreading of the lip parts is formed, wherein in the lateral surfaces an angular subdivision is provided, the angle of which is less than 180 °, so that the lip parts (28; 29) in the installed state seal the sealing surfaces, but nooh slide have capable preload, and that the opening angle of the groove ring (6) is smaller than the Druokwinkel of the Druokringss (7) is held - For this 2 sheets of drawings -