The present invention refers to a flexible glove for sealing bearing fluid channels of an aerostatic bearing compressor, more particularly aerostatic bearing compressors applied to cooling systems.
As a general rule, a cooling cycle comprises four essential elements, namely a compressor, a condenser, an expansion valve and an evaporator. In this cooling cycle, a cooling fluid (Freon®, for example) circulates through said components where the following operations occur. In the expansion valve, the cooling fluid which is found originally in liquid form, expands to enter into a gaseous and rarefied form, decreasing its own temperature. Subsequently, this fluid, now with lower density, passes through an evaporator enabling it to absorb heat from the environment. Next, the fluid comes to a compressor which compresses the fluid returning it to liquid form (or compressed gaseous form). Lastly, the fluid passes through a condenser transmitting heat to a second environment, and these stages restart when the fluid returns to the expansion valve, thus concluding the cooling cycle.
Cooling compressors may present various different forms, mechanisms and functions. Each type of compressor is better adapted to a certain type of application, and a compressor model widely known in the state of the art is the linear compressor. This compressor operates by way of the axial and oscillatory movement of a piston inside a cylinder.
The gas that enters into a linear compressor proceeds along the following path: firstly the gas penetrates into a plenum chamber, next it passes through an inlet valve and soon after fills a region called the compression chamber, that is, a region comprised by the space between the piston and the cylinder of the compressor where there occurs compression capable of transforming it into a liquid or gas having greater density. In a third moment, this fluid, now having greater density, is displaced through a discharge valve and lastly, the fluid fills a region called the discharge chamber from where it is released for the next stages of the cooling cycle.
It is noted that for correct working, linear compressors need lubrication between the outer face of the piston and the inner face of the cylinder. The purpose of said lubrication is to decrease attrition between the parts, whereby increasing the yield of the compressor and avoiding premature wear and tear of its parts. Accordingly, there are linear bearing compressors with viscous fluids, of the lubricant oil type and linear bearing compressors with gaseous fluids.
Linear bearing compressors with gaseous fluids are called aerostatic bearing linear compressors. Said compressors are endowed with a more efficient lubrication system than the lubrication system of the bearing compressors with viscous fluids due to the lower viscous attribution coefficient of the gaseous fluid in relation to the viscous fluid (oil). Another advantage of the linear aerostatic compressor refers to the absence of an oil pump to distribute the viscous fluid inside the compressor, a fact that decreases the manufacturing cost and complexity of this product.
An important characteristic of aerostatic bearing linear compressors, hereinafter referred to as aerostatic compressors, refers to the fact that they can have bearing formation through the gas from the cooling fluid itself. As they have bearing by the very cooling fluid that circulates through the compressor, this equipment saves on an extra source of lubricant, since all the lubricating fluid necessary for using these compressors is already abundantly available inside them.
The aerostatic bearing compressor with cooling fluid is endowed with bearing channels, located on the outer face of the cylinder. These channels are capable of distributing the gaseous fluid to distribution orifices which are spread along the cylinder. The distribution orifices cross through the structure of the cylinder, meeting up with the piston region, transporting gaseous fluid homogenously to the gap existing between the cylinder and the piston.
So that the gaseous fluid is uniformly distributed in the gap between the piston and the cylinder, it is necessary to seal the bearing channels, preventing communication between them and the pressurized fluid outlet which will work in the bearing formation of the piston.
Usually, the part that fulfills the function of sealing the bearing channels is a metal jacket having tubular geometry, referred to hereinafter as sealing jacket.
It is noted that between the inner surface of the sealing jacket and the outer surface of the cylinder there may be gaps which besides allowing undesirable communication between the bearing channels, may increase the sectional area of certain restriction channels, whereby causing a greater flow of fluid in these channels and, consequently, lead to poor fluid distribution in the gap between piston and cylinder, resulting in irregular bearing formation.
For effective sealing of the restriction channels, it is necessary to carry out interference coupling between the sealing jacket and the cylinder, usually made of metal material. Besides this operation, it is also necessary to carry out fine surface finishing with a view to obtaining a surface endowed with low roughness both on the outer face of the cylinder and on the inner face of the jacket.
However, a fine surface finishing requires a size tolerance that adds cost and increases the manufacturing time of these parts due to the frequent need of turning and grinding processes on both the parts.
Moreover, there is the drawback that interference coupling between the sealing jacket and the cylinder may deform the cylinder whereby characterizing another drawback to the arrangement of jackets in aerostatic compressors of the state of the art.
A sealing jacket of aerostatic compressors of the state of the art, such as the one mentioned, is made of metal material, that is, a material having low flexibility, which requires a thorough surface finishing so that it is capable of sealing the bearing channels of the compressor.
Nevertheless, even if a thorough job is performed in the manufacture of the sealing jacket and cylinder of the compressor, there is still the possibility that flaws may arise in the end product due to poor distribution of fluid between the piston and the cylinder, which may decrease the yield of the compressor and/or damage its internal parts, whereby decreasing its useful life. This occurs because the metal constitution of the sealing jacket and of the cylinder of the compressor prevent a perfect sealing of the restriction channels, even if various machining and grinding operations are carried out on these parts with a view to achieving greater precision in the surface finishing of these components.
Therefore, there is still no sealing jacket of an aerostatic linear compressor that decreases the complexity and cost of the manufacturing process of this equipment, efficiently guaranteeing the sealing of the bearing channels and that prevents the occurrence of flaws arising from the interference coupling process between the parts of the compressor.
The objective of the present invention is to provide a sealing system of bearing channels of aerostatic linear compressors that is simple, efficient and capable of reducing production costs of aerostatic linear compressors.
Another objective of the present invention is to provide a sealing glove of restriction channels of aerostatic linear compressors, the flexibility of which allows the sealing of restriction channels in aerostatic compressors, whereby preventing gas from escaping between the restriction channels.
A further objective of the present invention is to provide a cooling system or appliance, endowed with said sealing glove.
The objectives of the present invention are achieved by a sealing glove for a cylinder of a linear compressor de aerostatic bearing, the cylinder being defined by an outer surface and an inner surface, the inner surface defining a through cavity inside the cylinder, capable of enabling linear movement of a piston on its inside, wherein the inner surface of the cylinder comprises a plurality of distribution orifices which communicate with the outer surface, the outer surface comprising bearing channels capable of communicating with said distribution orifices, the glove being flexible and disposed on the outer surface of the cylinder under radial tension, the association between the outer surface and the sealing glove defining bearing formation ducts capable of directing the bearing fluid to the distribution orifices.
The objectives of the present invention are also achieved by an aerostatic bearing linear compressor comprising a cylinder defined by an outer surface and an inner surface, the inner surface defining a through cavity inside the cylinder capable of enabling a linear movement of a piston in its inside, wherein the inner surface of the cylinder comprises a plurality of distribution orifices which communicate with the outer surface, the outer surface comprising bearing channels which communicate with said distribution orifices, and a sealing glove is disposed on the outer surface of the cylinder under radial tension, the association between the outer surface and the sealing glove defining restriction ducts capable of directing the bearing fluid to the distribution orifices at appropriate pressure and in the adequate quantity.
Lastly, an objective of the present invention is to provide a cooling appliance which comprises a sealing glove as defined above.
The present invention shall now be described in greater detail based on an example of an embodiment represented in the drawings. The drawings show:
FIG. 1—is a longitudinal cut view of an aerostatic linear compressor of the present invention endowed with the flexible sealing glove of the present invention;
FIG. 2—is a cross-sectional view of a flexible sealing glove of the present invention positioned on a cylinder of an aerostatic linear compressor;
FIG. 3—is a perspective view of a cylinder of an aerostatic linear compressor of the present invention;
FIG. 4—is a perspective view of a cylinder of an aerostatic linear compressor endowed with a flexible sealing glove of the present invention;
FIG. 5—is a cross-sectional view of the BB section of an aerostatic compressor linear endowed with a glove of the present invention;
FIG. 6—is a cross-sectional view of a flexible sealing glove of the present invention;
FIG. 7—is a cross-sectional view of a flexible sealing glove of the present invention showing one of the potential effects of internal pressure on the bearing channels;
FIG. 8—is a cross-sectional view of a flexible sealing glove of the present invention showing one of the potential effects of internal pressure on the bearing channels in light of the external pressure to the flexible glove;
FIG. 9—is a longitudinal cut view of an aerostatic linear compressor illustrating its working during the suction stage;
FIG. 10—is a longitudinal cut view of an aerostatic linear compressor illustrating its working during the compression stage;
FIG. 11—is a longitudinal cut view of an aerostatic linear compressor illustrating its working during the exhaust stage;
FIG. 12—is a longitudinal cut view of part of the compressor of the present invention in an alternative arrangement illustrating an interface region;
FIG. 13—is a perspective view of a first alternative arrangement of the cylinder of the compressor of the present invention;
FIG. 14—is a perspective view of a second alternative arrangement of the cylinder of the compressor of the present invention; and
FIG. 15—is a perspective view of a third alternative arrangement of the cylinder of the compressor of the present invention.
The main elements that make up an aerostatic linear compressor 200 capable of receiving the sealing glove 100 of the present invention, as can be noted in
So that the piston 15, of the aerostatic compressor 200 of the present invention has bearing in the contact region between cylinder 14 and piston 15, it is necessary that under the inner surface 4 of the cylinder 14 there be a layer of fluid preferably gaseous that reduces the attrition between these parts, decreasing the abrasion between them and increasing the yield of the compressor 200. Notably, the present invention has application in aerostatic compressors 200 which use the cooling fluid itself to perform the bearing function.
The provision of this fluid layer, capable of bearing the piston 15 inside the cylinder 14 of an aerostatic compressor 200 can be better understood by way of
The major part of the fluid which enters the exhaust chamber 11c, returns to the cooling cycle of the cooling system where the compressor 200 is inserted, through the exhaust tube 9; a second portion of fluid, the portion which filled the exhaust chamber 11c and did not return to the cooling cycle, follows a third cycle (a cycle present only in aerostatic linear compressors 200 that use the very cooling fluid to carry out the function of bearing formation of the piston 15).
This second portion of fluid penetrates into a passage 10c, located on a header 10 and then follows bearing channels 1,2, which direct this fluid to distribution orifices 3 which, in turn, have the function of providing a chamber of gaseous fluid between the inner surface 4 of the cylinder 14 and the outer surface of the piston 15.
As described, the compressor 200 of the present invention is endowed with bearing channels 1,2, located on the outer surface 5 of the cylinder 14, whose function is to distribute (and restrict) fluid to distribution orifices 3, which, in turn, pass on this fluid to the gap existing between piston 15 and cylinder 14.
The bearing channels 1,2, may present various forms and different arrangements, and may track different paths on the outer surface 5 of the cylinder 14, such as, for example, along radial, longitudinal, helical, diagonal paths, a combination between these or any other capable of adequately performing the function (see FIGS. 13,14,15). The sectional areas of these bearing channels 1,2 may also present various different forms such as, a triangular, quadrangular, rounded geometry, among others. The bearing channels 1,2 can also be divided into feeder channels 2 and restriction channels 1, such as illustrated in a preferred arrangement in
The feeder channels 2 are commonly disposed in longitudinal profiles along the cylinder 14 (see
So that these bearing channels 1,2 effectively fulfill the function of distributing bearing fluid in a uniform manner to the distribution orifices 3, it is necessary that these channels 1,2 are sealed by some type of outer surface of the cylinder 14 that is capable of preventing the flow of fluid of a certain channel 1,2 from leaking to a neighboring channel 1,2.
This sealing surface, when overlapping the channels bearing formation 1,2, define bearing formation ducts 1′,2′. The bearing formation ducts 1′,2′, by presenting a closed structure (differently to the bearing channels 1,2), are effectively capable of providing fluid to the distribution orifices 3 without this fluid leaking from one channel 1,2 to the other channel 1,2.
Therefore, the present invention is focused on sealing these bearing channels 1,2 through the disposition of a flexible sealing glove 100 on the outer face 5 of the cylinder 4, such that the sealing glove 100 maintains the cylinder 14 under radial compression. Put otherwise, the sealing glove 100 of the present invention can be defined as a substantially tubular object, having a flexible/elastic constitution capable of providing the sealing of the bearing channels 1,2 through a radial tension which maintains its structure in contact with the outer surface 5 of the cylinder 14 (see
The sealing glove 100 of the present invention is made of a substantially polymeric material, that is, a material that may comprise composites, polymers, elastomers and any other materials endowed with organic substances, which have average or high flexibility and which have an elasticity limit capable of enabling this sealing glove 100 to be fastened to the cylinder 14, under radial tension, preventing the presence of gaps between the glove 100 and the cylinder 14. Furthermore, it has to be noted that for this radial tension to occur, it is also necessary for the inner diameter of the glove 100, when it is not tensioned, to be slightly less than the outer diameter of the cylinder 14, whereby enabling a tensioning of the glove 100 material on the outer surface of the cylinder 14.
In another preferred arrangement, it is possible for the inner diameter of the sealing glove 100 to present, before being applied to the cylinder 14, an inner diameter that is greater than the outer diameter of the cylinder 14. In these cases, the glove 100 may be made of a thermo-contractile material, that is, a material which, once heated, contracts so as to permit installation with a tight adjustment of the sealing glove 100 on the cylinder 14.
As described, the glove 100 has benefits such as better sealing of the bearing channels 1,2 due to a radial tensioning of its structure around the cylinder 14, being capable of eliminating the gaps existing between the glove 100 and the outer surface 5 of the cylinder 14, whereby improving the process of bearing formation of the piston 15 inside the compressor 200.
However, the flexibility of the glove 100 may potentially cause a drawback to the working of the compressor 200. Said flexibility allows the glove 100 to bend oppositely to its axial center ‘X’ in the regions comprised over the bearing channels 1,2, (as can be noted in
Yet this potential problem is solved by applying a positive pressure to the interface region 17 defined between the outer face of the sealing glove 100 and the inner face of the outer block 13. Said positive pressure, when operating on the outer face of the glove 100, neutralizes the force exerted by the positive pressure acting under the inner face of the glove 100 (see
In short, when its outer face is exposed to a pressure equal to the discharge pressure of the compressor 200, the flexible sealing glove 100 becomes capable of sealing the bearing channels 1,2, with greater effectiveness so as to avoid the leakage of fluid between said bearing channels 1,2.
However, even using a flexible sealing glove 100 and a positive pressure acting on its outer face, a third problem may still occur in the compressor 200. If the pressure acting on the outer face of the glove 100 is slightly greater than the pressure acting inside the bearing formation ducts 1′ and 2′, the sealing glove 100 may bend slightly towards the central reference axis ‘X’ (see
It is obvious that the linear aerostatic compressor 200 as well as the flexible sealing glove 100 of the present invention may comprise various constructive alternatives, related to different forms, materials and dispositions, provided that all these alternatives comprise the conceptual part of this invention, as disclosed in this specification.
Below are some alternative embodiment possibilities of the present invention:
Note that the alternative arrangements disclosed above are merely illustrative alternatives of countless possibilities that the present invention may comprise. It is also noted that the alternative arrangements both of the flexible sealing glove 100 and the compressor 200 of the present invention are not exhausted in this specification, and may comprise innumerous alterations, provided that they all comprise the conceptual part of the present invention.
Lastly, regarding the benefits achieved by the present invention, it can be said that the new arrangement of this glove 100 has benefits both in terms of the manufacturing process of the compressor 200, and in the utilization itself. In relation to the manufacturing process of the compressor 200, this polymeric sealing glove 100 dispenses with the need to perform rigorous processes on the surface finishing of the inner face of the glove 100, and on the surface finishing of the outer face of the cylinder 14. The elimination of such processes reduces costs, time and the complexity of production.
As for utilization of the compressor 200, it can be seen that this new technology increases its efficiency and its yield. Said attributions originate from the reduction of gaps between the sealing glove 100 and the cylinder 14 that are so common in the state of the art; the decreased risk of operating failures in the compressor 200 (since the compressor 200 that uses this new technique has a lower risk of presenting malfunctions because it does not have cracks and internal deformations arising from interference coupling between the glove 100 and the cylinder 14); and, lastly, owing to improved distribution of bearing fluid in the gap between piston 15 and cylinder 14 thanks to the elimination of leakage between the bearing formation ducts 1′,2′ of the compressor 200 along its extensions.
Lastly, it is noted that a compressor 200 containing the glove 100 as described may, among the most diverse applications, be used in the cooling industry.
Having described an example of a preferred embodiment, it should be understood that the scope of the present invention encompasses other possible variations, being limited only by the content of the accompanying claims, potential equivalents being included therein.
Number | Date | Country | Kind |
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PI1105470-0 | Nov 2011 | BR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/BR12/00452 | 11/14/2012 | WO | 00 |