Seal for a joint or juncture – Process of static sealing – Using flexible sleeve – boot – or diaphragm
Reexamination Certificate
2000-12-13
2003-04-22
Estremsky, Gary (Department: 3676)
Seal for a joint or juncture
Process of static sealing
Using flexible sleeve, boot, or diaphragm
C277S389000, C277S605000, C277S387000
Reexamination Certificate
active
06550776
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a vacuum packing configuration comprising a pneumatically or hydraulically expandable first packing part as well as a second packing part against which the first is stressed, forming a seal.
The present invention relates furthermore to vacuum treatment installations with a stator with an interior volume substantially having the shape of a body generated by revolution, for a rotor comprising a multiplicity of workpiece holding fixtures spaced apart with respect to a rotational drive axle, with the stator comprising a multiplicity of treatment and/or transfer-through ports communicating with the interior volume for workpieces of a workpiece holding fixture, and in which, further, each of the workpiece holding fixtures driven on the rotor is directly positionable at each of the ports on the stator and in each instance a pneumatically or hydratulically actuatable packing configuration hermetically seals the workpiece holding fixture at the port against the remaining interior volume of the stator.
A vacuum packing configuration of the above described type is known from European patent application EP 0 555 764 or U.S. Pat. No. 5,415,729. It comprises a metallic bellows tube which forms a sealing structure via a part comprising a resilient material, especially intended for this purpose, such as for example a polymer such as TEFLON material (TEFLON is a trademark) or an elastomeric material, against the passive second packing part.
This provision is often disadvantageous because of the following reasons:
Often the sealing tightness required in each instance for a pressure-expanded metallic bellows having a relatively large bellows front face, is dimensionally stable only if the front face is provided with a resilient part.
The resetting force which drives it back with a pressure relief due to the spring bellows effect, is relatively low and the return position of the bellows is relatively indeterminate.
A bellows is extremely costly, if not unsuitable, for the realization of long sealing contours.
Bellows are subject to resonance phenomena during operation, which drastically reduce their service life due to the resulting, possibly high-frequency, alternating loadings.
SUMMARY OF THE INVENTION
The present invention is based on the task of improving a vacuum packing configuration of the above-mentioned type with respect to said disadvantages.
This is accomplished according to the invention in that the first part is a resilient metal diaphragm.
Consequently, the invention builds on the finding that with such a diaphragm a precisely predeterminable sealing effect, uniformly distributed everywhere, can be attained and, in the returned state, a precisely predetermined return position is established. This permits working with very small packing displacements without parts, for example, being movable during sealing relative to one another, needing to fear highly undesirable, in terms of vacuum technology, frictional contact of the packing parts with the diaphragm returned. By providing said metal diaphragm, the above described disadvantages are eliminated simply and efficiently.
Such a packing configuration, moreover, is economically simple in its structure and permits, in particular, precisely self-resetting rapid sealing cycles—also due to the precise and thus very short sealing displacements.
This permits the realization of equipment with said advantages and thus the implementation of high treatment throughputs with small overall constructional size.
The packing configuration according to the invention further permits linear and/or curved sealing contours.
By proceeding according to other features of the invention, i.e. by structuring the diaphragm such as is the case with aneroid capsules, with beads, the stress of the diaphragm through the alternating stressing is reduced.
It is further unnecessary to provide resilient formations at the sealing faces in order to achieve, reliably and uniformly distributed, the requisite sealing pressure. Other features of the invention also permit structuring of the second part of the packing configuration, at least to some extent, of metal. In this way it becomes possible to created, when establishing tightness and as a function of the sealing pressure, controlled metal/metal transitions and thus to establish thermal bridges between the parts to be sealed.
According to another feature of the invention, it can moreover be advantageous to structure at least one portion on the second part to be elastic or elastically mounted, for reasons of pulse damping, or in order to further improve the reliability of an established sealing, in particular in the case of an extensive sealing area.
The second packing part against which the active expandable part acts, can fundamentally also be active, i.e. expandable. For example, it can be structured identically to the first part or it can be passive, i.e. be sttuctured to be nonexpandable.
In EP 0 555 764 or U.S. Pat. No. 5,415,729, respectively, further, a vacuum treatment installation of the above-mentioned type is disclosed. The pneumatically or hydraulically actuatable packing parts are therein provided on the stator, while on the rotor the passive packing parts are disposed which enter with the former into the interaction forming a sealing.
While this may appear on first view to be advantageous by being able to carry the pressurization lines to the elastic packing hoses on the stator, i.e. exclusively on nonmoving housing parts, it is however known that in equipment or installations of this type, the total multiplicity of provided ports is not always equipped with treatment or transport stations, but that, depending on the treatment process to be completed one, or most often even several, of the provided ports are closed with covers so as to form a sealing. But entailed in this are relatively large expenditures in order not to damage, in the case of said not-inserted ports, the active packings provided initially. In such cases the entire provided pressure distribution system is also poorly utilized. Added to this is the fact that the pressure distribution at the individual packing configurations requires relatively long lines branched along the installation housing, with the particular relatively large line volumes having to be taken into consideration especially with rapid pressure buildup.
Under this aspect the present invention furthermore has as its object to improve substantially a vacuum treatment installation of this type. This takes place, according to other features of the invention, in that, rather than on the stator, each workpiece holding fixture on the rotor is provided with an encircling internal pressure-expandable packing part which is connected to the rotor by a pressurization line arrangement.
Furthermore, the active expandable packing parts on the installation according to the cited EP 0 555 764 are elastic packing hoses. In particular for highly pure treatment processes to be carried out, these are disadvantageous with respect to gas, diffusion and gas absorption (degradation of vacuum), with respect to thermal loadability and their service life. They are, furthermore, if at all, only undefined, application time-dependent, self-resetting as a function of temperature, which does not allow for rapid sealing cycles utilizing self-resetting. With respect to alternating pressure stressing, they act like lowpass filters.
These disadvantages are solved with the installation according to other characterizing features of the invention.
An installation combining various features of the invention is also proposed, which has combined advantages.
Preferred embodiments of the vacuum treatment installation are specified. A highly preferred embodiment uses the vacuum treatment configurations of the installation, in particular at the rotor side, that is structured as a diaphragm with all described advantages of this configuration.
REFERENCES:
patent: 2987218 (1961-06-01), Erickson
patent: 4014555 (1977-03-01), Jacottet
patent: 4735421 (198
Estremsky Gary
Williams Mark
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