MXPA97010107A - Cie provision - Google Patents

Abstract

The present invention relates to sealing assembly for a piston rod with a circular section, comprising a one-piece sealing ring with a dividing joint and compensation space as well as a cover ring surrounding or enclosing the sealing ring in the peripheral direction: the sealing ring has a section extending in the circumferential direction of the sealing ring at least at one end and forms a ring connection superimposed together with another end of the sealing ring and the sealing ring has a thickness of radial wall decreasing towards the dividing union, wherein the sealing ring has on its outer radial surface a recess extending along the circumference of the sealing ring, the covering ring fits in the recess and a surface of sealed which is a radial inner surface of the sealing ring

Description

CLOSURE PROVISION DESCRIPTION OF THE INVENTION The present invention relates to a closing arrangement according to the preamble of claim 1. The closing arrangements for a circular cross-section body such as a piston rod are known in particular for piston compressors. Dry stroke piston compressors are machines that do not require any extraneous lubrication in the compression part. Such compressors have fixed seal elements which move a piston rod. The closure elements are usually arranged one after the other in series and thus form the so-called package. Such a package with closing arrangements and sealing rings is known from CH 439 897. The sealing rings are subject to wear on the sealing surface which lies against the piston rod. In order to maintain, however, the function of closing for long periods, the known locking ring has wear compensation since the closing ring is divided into three closing ring elements with partial joints extending parallel to a tangent with with respect to the piston rod and with radial joints forming a compensating ring gap. A hose spring peripherally surrounding the sealing ring exerts a preload on the sealing ring elements towards the piston rod. This known closing arrangement has the disadvantage that the closing ring has a large number of partial connections, which damage the closing function. In order to close these joints, a cover ring lying in contact in the axial direction is disposed adjacent the closure ring. Such a closing arrangement has the disadvantage that it has a relatively long degree in the axial direction. A known problem with such locking arrangements in the piston rods is the frictional heating that occurs. The heat dissipation of the friction via the closure elements by themselves is only possible with difficulty, since the closing elements are usually made of plastic and act thermally almost as insulators. The larger portion of the friction heat is thus conducted in a form less efficiently through the piston rod. The heat of the friction that arises, in this way is enormously responsible for the high wear, among other things, when using plastic sealing rings. In this way, a complicated and expensive cooling of the package containing the closing arrangement is usually required. It is an object of the present invention to overcome the disadvantages of known closing arrangements.

This object is satisfied according to the aspects of claim 1. The subordinate claims 2 to 9 relate to additional advantageous embodiments. The closing arrangement according to the invention for a piston rod with a circular cross-section, thus comprises a one-piece closure ring with a ring gap and a clearing gap, as well as a covering ring surrounding or by enclosing the closure ring in the peripheral direction, the closure ring has a section at least at one end of which, together with the other end of the closure ring, forms an overlapping ring gap, and with the closure ring having a wall thickness reducing towards the joining of parts or ring gap, respectively. An advantage of the closure arrangement according to the invention is that it can be seen that the overlapping ring gap in the axial direction produces a high degree of gas tightness. The surrounding or enclosing cover ring assists the closing section and also exerts a diverting load acting on the closing ring towards the piston rod. The surrounding or enclosing cover ring seals the overlap part in the radial direction. Suitable materials for the sealing ring are plastics for dry running applications, such as polymers filled with a mixture of polytetrafluoroethylene (PTFE) or a mixture of mechanically solid polymers, resistant to high temperatures and resistant to wear, which are also referred to as "high temperature polymers", such as poly (ether ether) ketone) (PEEK), poly (ether ketone) (PEK) polyimide (Pl), poly (phenylene sulfide) (PPS), polybenzimidazole (PBI), polyamideimide (PAI) or also epoxy resin. High temperature polymers are not capable of running dry in their pure form and, therefore, require additional solid lubricants, such as carbon, graphite, ibidine sulfide, PTFE, etc. Such high temperature polymers are then designated as "modified." An advantage of the closure arrangement according to the invention is seen in the fact that the closure ring made of a particular high temperature polymer can be used. The term "high temperature" polymer serves as a collective term for the use of sealing elements in piston compressors for plastic, which are distinguished from custom filled PTFE materials by the following properties: - Polymers of High temperature have a high mechanical stability even at high temperatures that are usual in dry operation. -, The high temperature polymers do not have cold flow properties, for this reason the finally configured sealing rings remain stable in shape and in particular do not require any support ring when used in a package even at high pressures. - The high temperature polymers have a substantially higher modulus of elasticity, which leads to a higher stiffness for larger ring diameters of a closing ring. - With the high temperature polymers the sealing rings can be manufactured, which, compared to the full PTFE, have substantially smaller diameters and, however, a substantially high mechanical load capacity, so that such sealing rings made of high temperature polymers are suitable in particular for use at high compression final pressures. A previous disadvantage in the use of high temperature polymers is seen in the fact of the poor ability to adopt a specific shape which makes it difficult to achieve full contact of the sealing ring over the entire periphery of the piston rod, so that the spill occurs. The closing ring according to the invention has the advantage that the closing ring has a radial wall thickness, which is reduced towards the joining part or the ring gap respectively, which means that the closing ring is Make it a little thinner, and in this way softer in flexion in the region of the overlapping ring gap. By virtue of this design, a sealing ring consisting of high temperature polymers has a good matching capacity in shape. The seal ring according to the invention is particularly suitable for dry stroke ring piston compressors, the sealing ring preferably consists of a high temperature polymer modified with so-called self-lubricating properties. A locking ring of this type can be manufactured with a very narrow ring, so that, on the one hand, the piston rod transmits heat better via the heat of radiation to the package, and on the other hand, there is a frictional surface smaller between the closing ring and the piston rod, which reduces the heating. In this way, excessive heating of the piston rod can be avoided, which has the additional advantage that the closing ring is subject to reduced wear. The closure arrangement according to the invention has a high impermeability, so that only a slight spill occurs through the closure arrangement, and the spill occurs mainly between the piston rod and the closing surface of the closure ring . During this, a gas support arises between the piston rod and the closing surface, which reduces the production of heat and in this way, in addition, the heating of the piston rod as well as the wear in the sealing ring.

Various illustrative embodiments of the invention will be explained in the following drawings. In which: FIG. 1 is a perspective view of a closing arrangement; Figure 2 a plan view of a closure ring; Figure 3 a bottom view of the closure ring; Figure 4 a cross-sectional view through the closure ring; Figure 4a shows an additional cross-sectional view through a closure ring along the line (B-B); Fig. 4b a further cross-section through the ring closure of Fig. 4a along the line (C-C); Figure 5 shows a further cross section through a closure ring and Figure 6 a plan view of a cover ring; Figure 7 a plan view of an additional illustrative embodiment of a closure ring; Figure 7a a side view of the closure ring of the Figure 2 from address E; Figure 7b a side view of the closure ring of Figure 7 from the direction E; Figure 8 a longitudinal view from a dry operation closing arrangement.

Figure 1 shows an exposure view of a closure arrangement 12 consisting of a closure ring 1, a cover ring 2 placed on the closure ring 1 in the direction of its periphery as well as a hose spring or toroidal spring 3 surrounding the cover ring 2 in the direction of its periphery. The plan view of the ring 1 shown in Figure 2 has a surface 1 h extending in the form of a circle along the internal circle facing the body to be sealed, a piston rod 4 and performs the closing function. The closing ring 1 is executed as a one-piece ring with a connection of part 1 a, so that the closing ring runs at both ends 1 b, 1 c. The end 1 c is executed in such a way that it has, as is evident from the inside view in Figure 3, a section 1 d extending in the peripheral direction of the closing ring 1, which together with the other end 1 b forms a ring gap overlapping a peripheral direction. The closing ring 1 has elastic properties so that it has a clear S in the region of the joining part 1 a. In the illustrative embodiment of the present, the closing ring is executed in such a way that its radial wall thickness D is continuously reduced towards the joining of part 1 to starting at the position Dmax opposite the joining of part 1 a, ie , in the address D1 or D2. In this way, even a closing seal, which is made of a material with a higher modulus of elasticity, such as a high temperature polymer for example, has a behavior that becomes increasingly more elastic and / or softer when flexed towards the union of part 1 a. The cover ring 2 with a hose spring 3 surrounding the closing ring 1 exerts a force on the sealing ring 1 acting towards the piston rod. The cover ring 2 is executed as an opening ring. By virtue of the clearance S in the connection of part 1 a, as well as in the elastic behavior towards the connection of part 1 a, the closing ring 1 has a good capacity to adapt to the shape of the piston rod 4, in a manner that the closing ring in closed form surrounds the piston rod 4 over its entire periphery. The closure ring 1 has a surface of 1 m, 1 n facing towards, and extending in the shape of a circle, in the illustrative embodiment, shown, the profiles of the two surfaces 1 h, 1 m are mutually arranged in such a way that extend eccentrically to each other. The closure ring 1 has five return flow slots 4a or pressure relief slots 4a extending in the radial direction. These pressure relief slots 4a allow (e.g., Figure 8) that a gas enclosed in the pack ring chamber 14 flows back into the cylinder during a cylinder consumption stroke., so that a double action closing function of the closure element 1, ie, a closing function both during the consumption phase as well as the compression phase of the cylinder, is avoided. It is also possible to execute a closing ring 1 with return grooves 4a. Rather, the return flow slots 4a can be ground in a metal base of the chamber ring 5, for example. Figure 6 shows an illustrative embodiment of an open cover ring 2, which has a section-shaped cut 2a. The closing ring 1 has a cylinder-shaped projection support means 1 g, which lie in the cut 2 a, when the cover ring 2 is placed on the closing ring 1, so that the cover ring 2 it is secured against rotation of the peripheral direction of the closure arrangement 12. Figure 7a shows a side view of the closure ring of Figure 2 from the direction E. The ring connection of the closing ring 1 has two ends 1 b, 1 c, the end 1 b has the end section 1 d extending in the peripheral direction, so that a ring gap overlaps in the peripheral direction. Figure 5 shows a section through a closing ring 1 along the line (AA) in Figure 2, with the joining of part 1 a is executed differently compared to the execution according to the Figures 1 to 3. At each end 1 b, 1 c of the closing ring 1 end sections 1 d, 1 e are placed extending in the peripheral direction of the closing ring 1, which overlap in the peripheral direction and thus form a joint of overlapping ring. The union of part 1 to another I I once has a clear S. The side view 7b of the closing ring 1 corresponds to a mode according to Figure 5 when seen from the direction B. The closing ring 1 runs at both ends 1 b, 1 c, the which have end sections 1 d, 1 e overlapping in the peripheral direction. Between the ends 1 b, 1 c there is an intermediate space of width S1 and S2 respectively. In a preferred embodiment, the two widths S1, S2 are made equally large so that the closure ring 1 has a clearance S = S1 = S2 in the peripheral direction. The cover ring 2 lies in the depression 1 n, the depression 1 n is so wide that the depression 1 n also extends over the end section 1 e in the peripheral direction, so that the cover ring 2 encloses the end section 1 e in the region of depression 1 n. A closing arrangement 1 2 of this type has a highly closing action, since the cover ring 2 encloses the intermediate space with the width S1 as well as with the gap between the end sections 1 d, 1 e, which gives as result in a high impermeability in the radial direction. In addition, the mutual relative movement of the two end sections 1 d, 1 e in the radial direction is avoided. Figure 4 shows a section through a closure ring 1 along the line A-a in Figure 2, with the additional possibility of the transverse design. The closure ring 1 has a surface 1 h facing a sliding surface of a piston rod 4. This surface 1 h has a high H in the axial direction and is designed to be cylindrically extended over a part 1 i in order to form a closing surface 1 i and is designed to diverge along an additional part 1 k. The diverging surface 1 1 can be executed, for example, to be conically divergent at an angle β. The closing arrangement 12 according to the invention has an excellent closing effect, since a flow passed in both the axial and radial directions is avoided. In this way, the gas constituents escape mainly between the sealing surface 1 i and the sliding surface of the piston rod 4, which has the advantage that the sealing ring 1 can be easily lifted off the sliding surface and the friction in this way it is reduced. The diverging surface 11 has the effect that the flow of unimpeded gas constituents in the direction towards the reduced closing surface 1 i, with the gas constituents exerting a force on the closing ring 1 which acts outward in the radial direction both on the surface 11 as well as on the surface 1 i. In this way, a spill is provided between the closing surface 1 i and the sliding surface of a piston rod 4. In this way, a gas support arises between the sealing ring 1 and the piston rod 4. The surface of Closing 1 i can be made relatively narrow in its axial degree in order to produce a pronounced gas support. In this way, the friction between the closing surface 11 and the piston rod 4 can be reduced, which has the advantage that both the heating and the wear of the sealing ring 1 are reduced. The closing ring 1 has a closing depression 1 n for receiving the cover ring 2. This depression 1 n can also be executed in a different way, or it can be absent. Figure 8 shows a longitudinal section through a dry operation closing arrangement or a so-called package 6. Therein belongs at least one closing chamber 14, which surrounds the piston rod 4 and is formed of two chamber rings 5, and which is screwed in sealed form to the associated cylinder space 15. A two-part closure ring disk 12 comprising a closing ring 1 as well as a cover ring 2, is placed in the closing chamber 14. In addition, a hose spring 3 surrounds the cover ring 2. As a result of the closing function ring 1, the pressure P1 in the compression chamber 14 is greater than the pressure P2 in the passage opening towards the next compression chamber 14. In a distinction to the embodiment of Figure 2, the illustrative embodiment of the closure ring 1 illustrated in FIG. Figure 7 has a surface 1 h with a cone-shaped partial surface 11. The partial surface 11 is interrupted in three places by a band 1 p. It also proves advantageous to have more than three bands 1 p distributed around the periphery. Figure 4 shows a section through the closure ring 1 along the line BB and shows the cone-shaped partial surface 1 1, which extends in the axial direction over a width of 1 k, as well as the surface partially cylindrically extended 1 i. The partial surface 11 extends in the cone shape, crosses the surface of the piston rod 4 at an angle β. Figure 4b shows a section through a band 1 p of the closure ring 1 along the line C-C. A band 1 p is executed so that the inner surface 1 h has a width in the axial direction corresponding to the width h of the closing ring 1 and extends parallel to the piston rod 4. A band 1 p is found in contact with the piston rod 4 over the entire width H and serves to stylize the closing ring 1. The illustrative embodiment according to Figure 7 has three bands 1 p arranged so that they are distributed on the periphery of the surface 1 h, a band 1 p is placed in the region of the junction of part 1 a. A closing ring 1 b can also be naturally executed without strips 1 p, so that the conical partial surface 1 1 extends over the entire periphery of the surface 1 h without interruption. The conically extended partial surface 11 has a maximum distance B towards the piston rod 4 according to Figure 4a. In a modality of the closing ring 1, the clear S becomes so wide that it has a width of "2 times pi times B". A closing ring 1 executed in this manner forms a friction ring in a first operation phase and a flow ring in a second operation phase. In the first phase of operation, the closing ring 1 has a conically extended partial surface 11. With the increase in wear on the closing surface 1 i, the conically extended partial surface 11 is decreased until the closing surface 1 i extends over the entire width H. Now, if the clear S is made to correspond with a width of "2 times pi times B", then the clear becomes zero as fast as the partial area 11 is completely corroded. In this state, the closing ring 1 becomes a flow ring because, since the clearance results in zero, during any wear of the closing surface 1 i occurs, so that the sealing ring 1 has an approximately constant leak during the second phase of operation. The closing ring 1 in this way has a maximum flow resistance during the second phase of operation. The partial surface 11 alone can not be executed to diverge conically, but it can have any arbitrary shape, so that a space arises in the region of the partial surface 11 between the piston rod 4 and the closing ring 1.

Claims (11)

I (> CLAIMS

1 . A closing arrangement for a piston rod with a circular cross-section, characterized in that it comprises a one piece closure ring with a part connection and a compression gap (S), as well as a cover ring surrounding or enclosing the ring of closure in the peripheral direction, the closure ring has a section, which extends in the peripheral direction of the closure ring at least at one end and forms an overlapping ring joint together with the other end of the closure ring, and the closure ring has a radial wall thickness (D) which is reduced towards the part union.

2. The closure arrangement according to claim 1, characterized in that the closure ring has a circularly extending surface oriented radially inwardly towards a body to be sealed; and the closure ring has a surface on its radially outer side extending circularly in the peripheral direction of the closure ring and eccentric to the surface.

3. The closing arrangement according to one of claims 1 or 2, characterized in that the closing ring has safety means in order to prevent a mutual rotation of the closing ring and the covering ring.

4. The closure arrangement according to one of claims 1 to 3, characterized in that the cover ring has resiliently flexible properties and / or is surrounded by a spring that is located on the cover ring and extends in the circumferential direction of the ring closing.

5. The closure arrangement according to one of claims 1 to 4, characterized in that the closure ring has a surface oriented radially inward towards the body to be sealed; the surface has a height (H) in a direction extending perpendicular to the peripheral direction of the closure ring; on the cylindrically shaped surface on a portion of the height (H) in order to form a closure surface and has a surface with an enlarged radius with respect to the closure surface on the additional part.

6. The closing arrangement according to claim 5, characterized in that the surface becomes conically divergent.

7. The closing arrangement according to one of claims 5 or 6, characterized in that the surface diverges in the radial direction at a maximum distance B; and the compensation clearing (S) has a width of "2 times pi times B".

8. The closing arrangement according to one of claims 5 to 7, characterized in that a plurality of bands is arranged distributed along the surface in the peripheral direction.

9. The closure arrangement according to one of claims 1 to 8, characterized in that the closure ring is made of a plastic such as polytetrafluoroethylene (PTFE) or a modified high temperature polymer such as poly (ether ether ketone), ( PEEK), poly (ether ketone) (PEK), polyimide (Pl), poly (phenylsulfide) (PPS), polybenzimidazole (PBI), or polyamidoimide (PAI).

10. A package for sealing a piston rod with closing arrangements according to one of claims 1 to 9.

11. The piston compressor with a closing arrangement according to one of claims 1 to 9.