Rotary piston compressor

Abstract

The invention relates to a rotary piston compressor (1) for compressing gas, in particular carbon dioxide, in which compressor a side wall surface (7) of a housing side wall (4) and a planar sealing surface (8, 9) of each housing cover (5, 6) enclose a working chamber (10) and a rotary piston (3) is rotatably mounted in the working chamber (10) on an eccentric (11), wherein a planar seal receiving channel (18) is formed in each of the piston base surfaces (15, 16) of the rotary piston (3) and a planar seal (19) is located in each of the planar seal receiving channels (18), wherein, in order to press the sealing surface (20) of each planar seal (19) against the planar sealing surface (8, 9), outer-surface openings (21) are formed in the piston outer surface (17) of the rotary piston (3), which openings are connected in a pressure-transmitting manner to each planar seal receiving channel (18) via pressure feed-through lines (22) that are formed in the interior of the rotary piston (3) and in each case open into the planar seal receiving channel (18) on a side of the planar seal (19) facing away from the sealing surface (20).

Description

[0001] The present invention relates to a rotary piston compressor according to the preamble of claim 1.

[0002] Rotary piston compressors have been known for a long time. They are shown, for example, in US 4,105,375 and US 4,118,157.

[0003] A rotary piston of a rotary piston compressor is shown in WO 2020 / 159394 A1. In the technology disclosed therein, spring elements are arranged in the planar seal receiving channels to press the planar seals against the respective planar sealing surfaces of the housing covers of the working housing. In practice, these springs generally generate only small contact forces and usually serve only to maintain contact with the planar sealing surfaces. In the prior art, the actual seal is usually generated by a gas pressure acting on the seal, whereby the gas generating the gas pressure reaches the planar seal via gaps between the planar sealing surfaces of the housing covers and the piston base surfaces. This is disclosed, for example, in DE 24 02 558 A1.

[0004] The JP S56-094886 U proposes a rotary piston compressor in which the planar seal in the planar seal receiving channel is pressed against the planar sealing surface by a leaf spring. Additionally, a pressure transmission line leads into the planar seal receiving channel, into the area behind the planar seal. An externally open channel also leads into this area.

[0005] The object of the invention is to propose an improvement which ensures good sealing by means of planar seals, especially at higher gas pressures in the working space.

[0006] To solve this problem, the invention proposes a rotary piston compressor according to claim 1. It is thus provided that, for pressing the sealing surface of the respective planar seal against the respective planar sealing surface, openings are formed in the piston shell of the rotary piston, which are connected to the respective planar seal receiving channel via pressure transmission lines formed inside the rotary piston and opening into the respective planar seal receiving channel on a side of the respective planar seal facing away from the sealing surface.

[0007] The invention therefore no longer provides for the gas pressure to reach the planar seal via gaps. Instead, the invention proposes that openings are provided in the piston surface, which are directly connected to the planar seal receiving channel via pressure lines formed inside the rotary piston. The pressurized gas from the working chamber can act directly on the planar seal in the receiving channel through the openings in the piston surface and the pressure lines leading into the receiving channel, pressing it against the respective planar sealing surface of the respective housing cover.

[0008] This solution according to the invention has the advantage, on the one hand, that fewer parts are required to press the sealing surface of the respective planar seal against the respective planar sealing surface of the respective housing cover. Thus, the spring elements used in the planar seal receiving channel in the aforementioned prior art can be completely dispensed with in the invention. Most importantly, however, the invention utilizes the gas pressure from the working chamber area into which the respective outer surface opening of the rotary piston opens, in the corresponding area of ​​the planar seal receiving channel to press the respective planar seal with its sealing surface against the respective planar sealing surface of the respective housing cover. This automatically adjusts the contact pressure to the pressures currently present in this area of ​​the working chamber.This proves particularly advantageous when especially high pressures are achieved in the working chamber during the compression of the gas using the rotary piston compressor according to the invention.

[0009] A particularly preferred application for rotary piston compressors according to the invention is the compression of carbon dioxide, enabling its use as an environmentally friendly refrigerant or heat transfer fluid in a cooling or heating circuit. For this purpose, operating pressures of at least 80 bar, preferably at least 100 bar, must be achieved to compress the carbon dioxide so that it can be used as a refrigerant for cooling devices, air conditioning systems, or as a heat transfer fluid for building heating systems, heat pumps, and the like. The primary application for rotary piston compressors according to the invention is the compression of carbon dioxide. However, these compressors can, of course, also be used to compress other gases.

[0010] In this context, the term "gas" refers to anything that is gaseous under normal conditions, i.e., at a temperature of 20°C and a pressure of 1013.25 mbar. When the respective gas is compressed using a rotary piston compressor according to the invention, the gas, particularly carbon dioxide, can be brought into a transcritical or supercritical state, in which it is simultaneously liquid and gaseous. Nevertheless, for the sake of linguistic simplification, the term "gas" will be retained throughout the description of the present invention.

[0011] In rotary piston compressors according to the invention, the rotary piston is rotatably mounted on an eccentric. Rotary piston compressors according to the invention could therefore also be described as rotary piston compressors based on the conversion principle. The rotary piston could also be referred to as a rotating piston or simply as a rotor. The rotary piston compressor itself could also be described as a rotary piston compressor. The planar seals could also be described as piston base seals.

[0012] The pressure lines in the rotary piston are preferably tubular. They can, for example, be designed as a single bore or a series of interconnected bores inside the rotary piston. However, other configurations for the pressure lines in the rotary piston are also possible.

[0013] Preferably, the openings in the piston surface are designed to be spaced away from the piston base surfaces in the piston surface.

[0014] There are various options for manufacturing and arranging the planar seals within their respective planar seal receiving channels. A particularly cost-effective first group of solutions involves manufacturing the planar seals directly within the channels. For example, a preferred variant involves injecting the planar seals as injection-molded parts directly into the receiving channels. In other words, this variant involves manufacturing and arranging the planar seals directly within the receiving channels using an injection molding process. Alternatively, the planar seals can be 3D-printed and embossed within their respective receiving channels.In this variant, each planar seal is manufactured directly within the planar seal receiving channel by a pressure process and thus simultaneously positioned there. Another variant involves pressing the planar seal into the respective planar seal receiving channel as a molded part.

[0015] Alternatively, it is also possible to manufacture the planar seal first and then, after its manufacture, to position it in the planar seal receiving channel. It is therefore also possible for the planar seals to be prefabricated as inserts and placed as such into the respective planar seal receiving channel.

[0016] Preferred embodiments of the invention provide that the pressure lines are covered by a cap at their opening into the respective planar seal receiving channel. The use of such caps to cover the opening of the pressure lines in the respective planar seal receiving channel is particularly advantageous when the planar seals are formed directly in the planar seal receiving channel, for example, by injection molding or 3D printing. The caps can prevent the opening of the pressure lines from being accidentally closed during the manufacturing process of the planar seals. Of course, such caps can also be used when the planar seals are prefabricated as inserts and inserted as such into the respective planar seal receiving channel.It should be noted that the phrase "covering the aforementioned opening with the cap" does not mean that the caps create a pressure-tight seal on the respective openings of the pressure lines. The caps are merely placed on top. With sufficient gas pressure in the pressure lines, the gas can easily penetrate past the caps into the planar seal receiving channel, thus pressing the planar seals against the respective planar sealing surface of the housing cover. In other versions, the caps can also be omitted.

[0017] To minimize the number of parts, preferred embodiments of the invention provide that the planar seals in one of the planar seal receiving channels in one of the piston base faces are each formed in one piece. In other words, in such embodiments, there is always only one planar seal in each planar seal receiving channel. The planar seal of this planar seal receiving channel is then formed in one piece.

[0018] In rotary piston compressors according to the invention, it is advantageously provided that the side wall surface of the housing side wall is completely or at least partially trochoidal in a section plane parallel to the planar sealing surfaces of the housing covers.

[0019] The rotary piston has two or more corner regions. Advantageously, a radial seal is provided in each corner region to seal the rotary piston against the side wall surface of the housing. It is particularly preferred that the piston base surfaces in the area between each pair of corner regions of the rotary piston are bounded by a boundary line, wherein the boundary lines are each formed as an envelope of a family of trochoidal curves.

[0020] To press the respective radial seal against the side wall surface of the housing, there are various possibilities, which can also be combined. For example, in rotary piston compressors according to the invention, it can be provided that an elastic element, pointing towards the rotary piston, is integrally molded onto each radial seal to press the respective radial seal against the side wall surface of the housing. In preferred embodiments, instead of or additionally, the planar seal is used to press the respective radial seal against the side wall surface of the housing. Such embodiments can then provide that the planar seals each have contact surfaces for pressing the respective radial seal against the side wall surface of the housing.These contact surfaces of the planar seals can each be designed as inclined surfaces and act on corresponding inclined surfaces of the respective radial seal.

[0021] As illustrated later in the figure description, when gas is compressed using rotary piston compressors, different partial volumes are created in the working chamber. These volumes are separated from each other by the rotary piston and its corner sections, and different gas pressures prevail in these volumes during operation. Their size also changes continuously during operation. Depending on the rotational position of the rotary piston, gas is drawn into certain partial volumes of the working chamber, while at the same time, the gas is being compressed on another side of the rotary piston. Thus, low-pressure and high-pressure areas are created simultaneously on different sides of the rotary piston.To prevent gas from flowing through the shell openings, pressure lines, and planar seal receiving channels from the currently formed high-pressure side to the currently formed low-pressure side, the invention provides that the planar seals are sealed against the receiving planar seal receiving channel in the corner regions of the rotary piston on their side facing away from the respective seal surface. To achieve this seal, the planar seals can, for example, have sealing ribs, preferably on the side facing away from the seal surface, which are arranged in corresponding sealing rib receptacles in the planar seal receiving channel. In this way, areas of the planar seal receiving channel between two adjacent corner regions of the rotary piston can be sealed against adjacent areas of the planar seal receiving channel.

[0022] As is known for rotary piston compressors in general, rotary piston compressors according to the invention can also be designed with different gear ratios. The gear ratio is the ratio of the number of trochoidal arcs forming the side wall surface of the housing to the number of corners of the rotary piston. In rotary piston compressors according to the invention, the gear ratio is advantageously 1:2, 2:3, or 7:6.

[0023] In rotary piston compressors according to the invention, the gas inlet and / or the gas outlet can pass through the housing wall. Alternatively, it is also possible that the gas inlet and / or the gas outlet passes through the eccentric. Combinations of these are also possible.

[0024] The planar seals and / or any radial seals are preferably made of a polymer or of a polymer with a dry lubricant and / or reinforcing fibers. Examples of polymers that can be used include polyetheretherketone, polyamide-imide, polyoxymethylene, polyketone, polyamide, or polyethylene terephthalate. Examples of dry lubricants include polytetrafluoroethylene or molybdenum disulfite. Examples of reinforcing fibers include glass fibers or carbon fibers.

[0025] In preferred embodiments, the housing side wall and the housing cover each have a base body made of an aluminum alloy or cast iron. Preferably, a coating is applied to this base body to form the side wall surface of the housing side wall and the planar sealing surfaces of the housing cover. This coating can be, for example, a nickel-phosphorus layer, an aluminum oxide layer, or a dry-lubricating coating. A combination of at least two of these layers is also possible. These coatings can be applied directly to the base body. Alternatively, an open-pore adhesive layer can be present on the base body, onto which the coating is then applied. In the case of a base body made of an aluminum alloy, the adhesive layer can be, for example, an open-pore aluminum oxide layer, such as anodized aluminum or uncompacted hard anodized aluminum.Another type of carrier or adhesive layer consists of an open-pored, plasma-chemically oxidized aluminum layer. For base bodies made of cast iron, the carrier or adhesive layers can be formed, for example, by phosphating or sandblasting.

[0026] Unless otherwise misleading, the terms "ein" and "eine" used here are to be understood as meaning "at least one" and "at least one".

[0027] Further features and details of preferred embodiments of the invention are explained by way of example in the following description of figures based on various embodiments of the invention. These show: Figs. 1 to 21 show illustrations of a rotary piston compressor according to the invention with a ratio of 1:2 and variations thereof; Figs. 22 and 23 show illustrations of a rotary piston compressor according to the invention with a ratio of 2:3 and Figs. 24 to 39 show illustrations of a rotary piston compressor according to the invention with a ratio of 7:6.

[0028] Fig. 1Figure 1 shows an exploded view of the first embodiment of a rotary piston compressor 1 according to the invention. This rotary piston compressor 1 has a gear ratio of 1:2. The rotary piston compressor 1 comprises a working housing 2 and a rotary piston 3. The working housing 2, in turn, has a housing side wall 4 and housing covers 5 and 6 arranged on opposite sides of the housing wall 4. In this embodiment, these components of the working housing 2 are connected to one another by the screws 37 and the nuts 38. However, this is not mandatory; other connection methods are also conceivable.

[0029] The side wall surface 7 of the housing side wall 4 and the two planar sealing surfaces 8 and 9 of the respective housing covers 5 and 6 enclose the working chamber 10 arranged in the working housing 2. The rotary piston 3 is rotatably mounted on the eccentric 11 in the working chamber 10. In this first embodiment, the eccentric 11 is fixedly mounted on a drive shaft 30. As in Fig. 2 As can be seen, this drive shaft 30 terminates in a connecting pin 31, which protrudes from the rotary piston compressor 1 in the assembled state. A motor can be connected to this pin to rotate the drive shaft 30, and thus also the eccentric, about the axis of rotation 60. In this embodiment, the eccentric 11 is therefore rotationally fixed to the drive shaft 30 and also to the connecting pin 31, so that rotating the drive shaft 30 about the axis of rotation 60 automatically results in a corresponding rotation of the eccentric 11.

[0030] In this embodiment, an external toothing 32 is also non-rotatably connected to the drive shaft 30. This external toothing 32 engages with an internal toothing 33, which is non-rotatably connected to the rotary piston 3. Through this threaded engagement, the rotary piston 3 is rotated within the working chamber 10 when the connecting pin 31 or drive shaft 33 is rotated accordingly. The rotary piston 3 is rotatably mounted on the eccentric 11 within the working chamber 10.

[0031] The rotatable mounting of the drive shaft 30 in the working housing 2 is achieved via the bearings 34 and the retaining ring 36. The bearings 34 can be ball bearings, plain bearings, or the like. In the illustrated embodiment, the bearing 34 in the housing cover 5 is a ball bearing, and the bearing 34 in the housing cover 6 is a plain bearing. However, this is not mandatory and other configurations are possible.

[0032] Below the housing cover 6, and thus outside the working housing 2, a counterweight 35 is mounted on the drive shaft 30 in a rotationally fixed manner. This counterweight compensates for the imbalance caused by the eccentricity of the rotary piston 3. In the illustrated embodiment, the working housing 2 is surrounded by an outer shell 39 of the rotary piston compressor 1. However, this is not necessarily the case.

[0033] In the rotary piston compressor 1 of this first embodiment, a gas inlet 12 is provided for introducing the gas to be compressed into the working chamber 10, as well as a gas outlet 13 with a pressure relief valve 14 for releasing the compressed gas from the working chamber 10. As explained further below, this is particularly advantageous in the Figs. 3 to 6 to see.

[0034] The rotary piston 3 has two piston base surfaces 15 and 16, each facing one of the planar sealing surfaces 8 and 9 of the housing covers 5 and 6, and one piston shell surface 17 facing the side wall surface 7 of the housing side wall 4. Each piston base surface 15 and 16 has a planar seal receiving channel 18. A planar seal 19 is arranged in each of these planar seal receiving channels 18, with each planar seal 19 having a sealing surface 20 for contact with one of the planar sealing surfaces 8 and 9 of the housing covers 5 and 6. This will be explained in detail with reference to the following figures.According to the invention, in the rotary piston compressor 1 of this first embodiment, openings 21 are formed in the piston shell surface 17 of the rotary piston 3 to press the sealing surface 20 of the respective planar seal 19 against the respective planar sealing surface 8, 9. These openings are connected to the respective planar seal receiving channel 18 via pressure transmission lines 22 formed inside the rotary piston 3 and opening on a side of the respective planar seal 19 facing away from the sealing surface 20. This will be explained in more detail below, particularly with reference to the following. Fig. 7, 8 as well as explained in sections 11-13.

[0035] For the sake of completeness, it should be noted that the internal toothing 33 in the rotary piston 3 of this first embodiment is located in the Fig. 1 , 7 and 9 depicted, but in the Figs. 3 to 6 , 11 , 14 and 18 The omission of the internal toothing 33 in the aforementioned figures is a purely graphical simplification, which does not mean that the internal toothing 33 is actually missing.

[0036] Fig. 2 Figure 1 is a side view of the assembled rotary piston compressor 1 of this first embodiment, with the section plane AA shown. Figs. 3 to 6 The figures show simplified cross-sectional drawings of this section plane AA, illustrating the operation of the rotary piston compressor 1 by showing different positions of the rotary piston 3 during one revolution around the drive shaft 30 and its longitudinal axis. Arrow 42 indicates the direction of rotation of the rotary piston 3 in the working chamber 10.

[0037] In the Figs. 3 to 6It can be seen that the side wall surface 7 of the housing side wall 4, viewed in a section plane parallel to the planar sealing surfaces 8 and 9 of the housing covers 5 and 6, is completely trochoidal in this embodiment. The rotary piston 3 has two corner regions 25. In each of these corner regions 25, there is a radial seal 26 for sealing the rotary piston 3 against the side wall surface 7 of the housing side wall 4. The piston base surfaces 15 and 16 are each bounded in the area between any two corner regions 25 of the rotary piston 3 by a boundary line 27, which is an envelope of a family of trochoidal curves. The rotary piston 3 divides the working chamber 10 into a low-pressure side 40 and a high-pressure side 41 by means of its corner areas 25 and the radial seals 26 arranged there. On the low-pressure side 40, gas is introduced into the working chamber 10 via the gas inlet 12 when the rotary piston 3 rotates.Gas is drawn in. On the high-pressure side 41, whose volume decreases with increasing rotation of the rotary piston 3, the previously drawn-in gas is compressed, so that the gas pressure on the high-pressure side 41 increases continuously with rotation of the rotary piston 3. Once the desired gas pressure or compression is reached on the high-pressure side 41, the overpressure relief valve 14 opens, allowing the compressed gas to flow out of the working chamber 10 via the gas outlet 13. By appropriately adjusting or selecting a suitable overpressure relief valve 14, the degree of gas compression by the rotary piston compressor 1 before it flows out via the gas outlet 13 can be set. In short, the degree to which the gas is compressed in the rotary piston compressor 1 can be defined or adjusted.

[0038] The Figs. 3 to 6Figure 43 shows four different positions of the rotary piston 3 during one revolution and thus during the described compression process. This operating principle of rotary piston compressors 1 is well known and does not require further explanation. Arrows 43 in the Figs. 3 to 6 The arrows 44 illustrate the gas flowing in or drawn in through the gas inlet 12, which still needs to be compressed. The arrows 44 illustrate the already compressed gas flowing out through the gas outlet 13.

[0039] Fig. 7 The figure now shows a vertical section through the rotary piston compressor 1 of this first embodiment along a path in Fig. 2 indicated vertical section plane BB or section plane running along the axis of rotation 60 of the drive shaft 30, in which the inventive shell openings 21 and pressure feedthrough lines 22 are cut. Fig. 8 shows area D Fig. 7enlarged. In these two sectional views, it is clearly visible that each of the two piston base surfaces 15 and 16 has a planar seal receiving channel 18, with a planar seal 19 located in each of the planar seal receiving channels 18. The planar seals 19 each have a sealing surface 20 with which they bear against one of the planar sealing surfaces 8 or 9 of the housing covers 5 or 6 for sealing. In Fig. 8The figure shows in detail that the piston surface 17 of the rotary piston 3 has openings 21 in the surface of the piston surface. These openings are connected to the respective planar seal receiving channel 18 via pressure lines 22 formed inside the rotary piston 3. These pressure lines 22 open into the respective planar seal receiving channel 18 on the side of the planar seal 19 facing away from the sealing surface 20. In preferred embodiments, such as the one shown here, the pressure lines 22 are tubular. Specifically, they are formed as a series of interconnected bores inside the rotary piston 3. The openings 21 are arranged in the piston surface 17 at a distance from the piston base surfaces 15 and 16.Arrow 47, indicating the direction of pressurization, illustrates how the gas present at the corresponding pressure in the working chamber 10 passes through the shell opening 21 and the pressure feed line 22, pressurizing the planar seal 19 on the side opposite the sealing surface 20. This presses the sealing surface 20 against the respective planar sealing surface 8 or 9. This ensures that the gas pressure in the working chamber 10 is used to press the planar seal 19, with its sealing surface 20, against the corresponding planar sealing surfaces 8 and 9. This allows for a very good seal to be achieved even at very high pressures in the working chamber 10. In the illustrated embodiment according to... Fig. 8In the area of ​​the opening 23 of the pressure transmission line 22, a cap 24 is located in the planar seal receiving channel 18, which covers the pressure transmission line 22. This cap 24 is designed so that it does not impede pressure transmission. When sufficient pressure builds up in the pressure transmission line 22, gas can flow, preferably past the cap 24, into the planar seal receiving channel 18 on the side of the planar seal 19 opposite the sealing surface 20, in order to press the planar seal 19 with its sealing surface 20 against the respective planar sealing surface 8 to 9.

[0040] As explained at the beginning, the cap 24 can also be omitted. However, if the planar seal 19 is, as implemented here, injected as an injection-molded part into the respective planar seal receiving channel 18 or printed as a 3D-printed part into the respective planar seal receiving channel 18, the cap 24 prevents the respective opening 23 from being unintentionally closed during the formation or manufacture of the planar seal 19.

[0041] Fig. 9 shows a section through the rotary piston compressor 1 of this first embodiment along the in Fig. 3 The section plane CC shown, which runs through the corner areas 25 and the radial seals 26 of the rotary piston 3 arranged there. Fig. 10 shows area E Fig. 9enlarged. Here, it can first be seen how the radial seals 26, which seal the rotary piston 3, bear against the side wall surfaces 7 of the housing side wall 4. Two measures are implemented to generate the contact pressure necessary for sealing. Firstly, an elastic element 28, pointing towards the rotary piston 3, is molded onto the radial seal 26, which presses the radial seal 26 against the side wall surface 7 of the housing side wall 4. Secondly, the planar seals 19 also press the respective radial seal 26 against the side wall surface 7 by means of their contact surfaces 57. In the Fig. 10 , 14 and 16 The elastic element 28, which is formed on the radial seal surface 49 and attached to the radial seal 26, is designed as a kind of freestanding leaf spring. Fig. 17Figure 1 shows a variant in which the elastic element 28 is formed as a corresponding bulge on the side of the radial seal 26 opposite the radial seal surface 49.

[0042] Returning to Fig. 10 It should be noted that the contact surfaces 57 of the planar seal 19 for pressing the respective radial seal 26 against the side wall surface 7 are advantageously designed as inclined surfaces 45. The radial seal 26 has, as shown in Fig. 10 It is easy to see that there are preferably corresponding inclined surfaces 46 on which the contact surfaces 57 or inclined surfaces 45 of the respective planar seal 19 act.

[0043] Fig. 11 Figure 1 shows a perspective view of the rotary piston 3, with the planar seal 19 arranged on the piston base 15 in the planar seal receiving channel 18. On the opposite piston base 16, which is in Fig. 11Although not visible, this is also designed accordingly. The boundary lines 27 of the piston base surfaces 15 and 16 are also clearly visible here; these are formed between the corner regions 25 of the rotary piston 3 as an envelope of a family of trochoidal curves. The surface openings 21 provided for in the invention are arranged in the piston shell surface 17. In section FF, which is shown in Fig. 12 The pressure-transmitting connection according to the invention between the shell surface openings 21 and the planar seal receiving channel 18 via one of the pressure feed lines 22 is shown again. Apart from the one shown here in Fig. 12 The missing housing cover 5 corresponds to the representation according to Fig. 12 as already discussed Fig. 8So, essentially, reference can be made to what has been said above. However, it should be noted again at this point that in this embodiment, the planar seal 19 is injection-molded into the respective planar seal receiving channel 18. Of course, the planar seal 19 could just as easily be formed as a 3D-printed part or as a compression-molded part within the planar seal receiving channel 18, as already explained above.

[0044] Fig. 13Figure 1 shows an alternative example. Here, the planar seal 19 is prefabricated as an insert and, as such, inserted into the respective planar seal receiving channel 18. The web 58 of this planar seal 19 provides appropriate guidance when, according to the invention, the planar seal 19 is pressurized with gas pressure in the pressurization direction 47 through the shell opening 21, the pressure feed line 22, and the planar seal receiving channel 18 on the side facing away from the sealing surface 20, in order to press the planar seal 19 with its sealing surface 20 against the Fig. 13 Press the planar sealing surface 8 or 9 of the housing covers 5 or 6 (not shown) against it. In the alternative according to Fig. 13 No caps 24 are provided to cover the openings 23. This also applies to this variant according to Fig. 13 However, appropriate caps 24 could of course also be used to cover the openings 23.

[0045] Fig. 14 Figure 1 shows an exploded view of the rotary piston 3, in which the planar seals 19 and the radial seals 26 are shown separately from the rotary piston 3. Fig. 14 It is also clearly visible that the planar seals 19, which are arranged in one of the planar seal receiving channels 18, are preferably made in one piece. Fig. 14 The openings 23 of the pressure feedthrough lines 22 can also be seen in the planar sealing receiving channel 18.

[0046] Fig. 15 is a side view of one of the planar seals 19 from the in Fig. 14in the indicated direction 59. Here, below the already discussed inclined surface 45, the sealing rib 48 of the planar seal 19 can be seen, which, as explained below, serves to seal the planar seal 19 in the respective corner regions 25 of the rotary piston 3 on its side facing away from the respective sealing surface 20 against the planar seal receiving channel 18 that receives it. This sealing is particularly preferably achieved by arranging the aforementioned sealing rib 48 in a sealing rib receiving groove 50, which is located in the respective corner region 25 as a recess in the planar seal receiving channel 18. For this purpose, reference is made to the Figs. 18 to 21 referred. Fig. 18 Figure 1 shows a top view of one of the piston base surfaces 15 of the rotary piston 3, as well as the section lines or section planes GG and HH. The section line GG lies in the area of ​​the sealing rib receiving groove 50, as shown in Figure 2. Fig. 19can be seen. In the section plane HH, the rotary piston 3 is cut in the area of ​​the radial seal receiving channel 51, into which the radial seal 26 is inserted. Fig. 21 shows the same cut as Fig. 19 , however in Fig. 19 Each planar seal 19 is arranged in the respective planar seal receiving channel 18. It can also be seen how the sealing rib 48 of the respective planar seal 19 is arranged in the respective sealing rib receiving groove 50 in order to achieve the desired sealing effect.

[0047] As explained at the outset, the planar seals 19 and the radial seals 26 are advantageously made of a polymer, preferably with a dry lubricant and / or reinforcing fibers. The housing side wall 4 and the housing covers 5 and 6 advantageously have a base body made of an aluminum alloy or cast iron. To form the side wall surfaces 7 of the housing side wall 4 and the planar sealing surfaces 8 and 9 of the housing covers 5 and 6, a coating 29 is advantageously applied to the respective base body. This is also preferably the case in this first embodiment. For details and preferred embodiments of such a coating 29, reference is made to the explanations already given at the outset.

[0048] The Figs. 22 and 23Figure 1 shows, again in an exploded view, a second embodiment of a rotary piston compressor 1 according to the invention, which is largely identical to the first embodiment, so only the differences will be discussed here. The essential difference is that a gear ratio of 2:3 has been implemented. Accordingly, the rotary piston 3 of this embodiment also has three corner regions 25. The number of gas inlets 12 and gas outlets 13, as well as the pressure relief valves 14, is adjusted accordingly, as are the shape of the side wall surface 7 and the shape of the planar seal 19. Otherwise, however, the above applies, adapted as necessary, so further details are omitted. It should merely be noted that in Fig. 23 the in Fig. 22The internal toothing 33 shown is not depicted. In this embodiment as well, the boundary lines 27 of the piston base surfaces 15 and 16 running between the corner regions 25 have the form of an envelope of a family of trochoidal curves. The side surface 7 of the housing wall 4, viewed in a section plane parallel to the planar sealing surfaces 8 and 9 of the housing covers 5 and 6, is also completely trochoidal. The arrangement of the outer surface openings 21 and the pressure lines 22 in the rotary piston 3 according to the invention corresponds to the first embodiment and does not need to be explained again.

[0049] In the Figs. 24 to 39A third embodiment of a rotary piston compressor 1 according to the invention is shown. This is a variant with a gear ratio of 7:6. The rotary piston 3 of this rotary piston compressor 1 thus has six corner regions 25. The areas of the piston shell surface 17 located between the corner regions 25 are again designed such that the boundary lines 27 defining the piston base surfaces 15 and 16 are each formed as an envelope of a family of trochoidal curves. The side wall surface 7 of the housing side wall 4 has trochoidal arcs in a section plane parallel to the planar sealing surfaces 8 and 9 of the housing covers 5 and 6.

[0050] In contrast to the previously described embodiments of the rotary piston compressor 1 according to the invention, in this embodiment the eccentric 11 on which the rotary piston 3 is rotatably mounted in the working chamber 10 is not rotated as in the first two embodiments, but is rigidly arranged in the outer shell 39 of the rotary piston compressor 1. In this embodiment, the rotary piston 3, together with the working housing 2 and thus together with the housing side wall 4 and the two housing covers 5 and 6, is rotated about an axis of rotation 60 passing through the eccentric 11, while the eccentric 11 remains stationary. To achieve this, the rotary piston compressor 1 of this third embodiment has a rotor 53 that is non-rotatably connected to the working housing 2 by means of screws 37 and nuts 38, and which interacts with a stator 54 that is rigidly connected to the outer shell 39 of the rotary piston compressor 1.The rotor 53 and the stator 54 form a drive motor which rotates the working housing 2 with the rotary piston 3 mounted on the eccentric 11 in the working chamber 10 of the working housing 2.

[0051] A further difference between the third embodiment and the two previously described embodiments is that, in this third embodiment, the gas inlet 12 and the gas outlet 13 pass through the eccentric 11, and not, as in the first described embodiments, through the housing wall 4. Accordingly, overflow openings 55 penetrating the piston surface 17 are also provided in the rotary piston 3. Through these overflow openings 55, the gas can enter the corresponding sections of the working chamber 10 from the gas inlet 12 in the eccentric 11 and from there be conveyed out again in compressed form via the gas outlet 13.

[0052] In this third embodiment, the gas inlets 12 and gas outlets 13 passing through the eccentric 11 open into a valve cover 52, which sits on the outside of the outer shell 39 of the rotary piston compressor 1 and directs both the gas inlet 12 and the gas outlet 13 into and out of the rotary piston compressor 1.

[0053] Apart from the differences described so far and below, reference can essentially be made to the description of the first embodiments. This applies in particular to the inventive method of pressurizing the planar seals 19 arranged in the planar seal receiving channels 18 of the piston base surfaces 15 and 16, for pressing their sealing surfaces 20 against the planar sealing surfaces 8 and 9 of the housing covers 5 and 6.

[0054] Fig. 25 shows the exploded view in Fig. 24The rotary piston compressor 1 of the third embodiment is shown in a side view. Fig. 25 The section plane II is shown. Figs. 26 to 32 Each section shows cross-sections in section plane II of various snapshots taken during the operation of the rotary piston compressor 1 and thus during the rotation of the working housing 2 together with the rotary piston 3 about the corresponding axis of rotation 60 running through the eccentric 11, which is shown in the Figs. 24 and 25 is shown. To control the rotational movement of the rotary piston 3 and the working housing 2 in the Figs. 26 to 32 To better understand this, it is located on the rotary piston 3 in the Figs. 26 to 32 Point 61 is marked. This is only a visual aid to show the instantaneous position of the rotary piston 3 in the various representations according to Figs. 26 to 32 can be better understood.

[0055] The Figs. 26 to 32This illustrates various intermediate stages during a revolution of the working housing 2 and the rotary piston 3 around the axis of rotation 60. The gas inlet 12 and the gas outlet 13 are clearly visible in the eccentric 11. Arrows 43 illustrate the gas flowing into the respective sections of the working chamber 10, currently functioning as the low-pressure side 40, via the gas inlet 12 and the corresponding transfer openings 55, which is yet to be compressed. Arrows 44 illustrate the compressed gas that has already been forced from the corresponding high-pressure side 41 of the working chamber 10 into the gas outlet 13. Following the position of the rotary piston 3 via the Figs. 26 to 32As can be seen, the partial volumes of the working chamber 10, designated as the low-pressure side 40 in the respective illustration, are connected to the gas inlet 12 via the corresponding overflow openings 55 in the rotary piston 3, allowing gas to flow in. In the partial volumes of the working chamber 10 designated as the high-pressure side 41, where there is no longer a connection to the gas inlet 12, the gas is then compressed by a corresponding relative movement between the rotary piston 3 and the working housing 2, so that it can then flow in compressed form into the gas outlet 13 when the corresponding partial volume of the working chamber 10 is connected to the gas outlet 13 via the corresponding overflow opening 55 in the rotary piston 3.

[0056] Fig. 33 shows a top view of the third embodiment of the rotary piston compressor 1 according to the invention. Fig. 33 The cutting planes JJ and KK are also shown. Fig. 34shows the section in the section plane JJ. In this Fig. 34 It is clearly visible how the gas inlet 12 passes through the valve cover 52 and the eccentric 11. It is equally clear how the gas outlet 13 also passes through the eccentric 11 and the valve cover 52. The overpressure relief valve 14, located in the gas outlet 13 in the area of ​​the valve cover 52, is also shown. This is a spring-loaded valve that opens when the compressed gas coming from the working chamber 10 or from a high-pressure side 41 is below the desired pressure, which can be set by the design of the overpressure relief valve 14.

[0057] In the cut according to Fig. 34The planar seals 19 can also be seen in the piston base surfaces 15 and 16 in the corresponding planar seal receiving channels 18, which accordingly seal with their sealing surfaces 20 against the planar sealing surfaces 8 and 9 of the housing covers 5 and 6.

[0058] Fig. 35 shows the section along the cutting plane KK. Fig. 33 This is a section plane in which the shell surface openings 21 and pressure feedthrough lines 22 according to the invention are arranged. The corresponding detail L from Fig. 35 is in Fig. 36The image is shown enlarged. It is clearly visible here that, in this embodiment as well, to press the sealing surface 20 of the respective planar seal 19 against the respective planar sealing surface 8 or 9, openings 21 are formed in the piston shell surface 17 of the rotary piston 3. These openings are connected to the respective planar seal receiving channel 18 via pressure transmission lines 22 formed inside the rotary piston 3, each opening on one side of the respective planar seal 19 facing away from the sealing surface 20. Fig. 36The direction of pressure application to the planar seal 19 on its side facing away from the sealing surface 20 is again illustrated by arrow 47. As in the first two embodiments, in this third embodiment the gas present under pressure in the working chamber 10 can also act on the side of the planar seal 19 opposite the sealing surface 20 via the shell opening 21 and the pressure line 22 passing through the rotary piston 3, in order to press the planar seal 19 with its sealing surface 20 against the corresponding planar sealing surface 8 or 9 of the corresponding housing cover 5 or 6.

[0059] In Fig. 36 Cap 24 is also shown, and its function has already been explained. Of course, cap 24 can also be omitted here.

[0060] Fig. 37Figure 1 shows a perspective view of the rotary piston 3 of this embodiment of the rotary piston compressor 1. This perspective view clearly shows how the planar seal receiving channel 18 is formed in the piston base 15 and how the planar seal 19 is arranged therein. The overflow openings 55 and the surface openings 21 arranged in the piston shell 17 are also clearly visible. Fig. 38 Figure 1 shows an exploded view of this, in which the planar seal 19 has been removed from the respective planar seal receiving channel 18 of the respective piston base surfaces 15 and 16. Fig. 38 The openings 23 in the planar sealing channel 18 can therefore be seen, which are connected to the corresponding shell surface openings 21 via the corresponding pressure feed lines 22.

[0061] The inwardly pointing sealing ribs 48, which are integrally formed on the planar seals 19, are arranged in the corresponding sealing rib receiving grooves 50 of the rotary piston 3 in the assembled state. As in the other embodiments, they ensure that the planar seals 19 are sealed in the corner regions 25 of the rotary piston 3 on their side facing away from the respective sealing surface 20 against the planar seal receiving channel 18 that receives them.

[0062] How particularly good in the Fig. 37 , 38 and 39As can be seen, the planar seals 19 of this embodiment each have sealing corner areas 56 with correspondingly rounded contact surfaces 57. These rounded contact surfaces 57 seal against the corresponding rounded corner sections 62 of the side wall surface 7 of the housing side wall 4 when the respective corner area 25 of the rotary piston 3 engages in the corresponding corner section 62 of the housing side wall 4. The corner sections 62 are in Fig. 24 as such. When the respective sealing corner area 56 rolls out in the corner section 62, the sealing corner area 56 with its rounded contact surface 57 always lies at least at one point between the two in Fig. 39 The endpoints X and Y shown are sealed at the corresponding corner section 62 and thus at the side wall surface 7. legend Regarding the reference numbers: 1 Rotary piston compressor 28 elastic element 29 coating 2 work housing 30 drive shaft 3 rotary piston 31 Connection pin 4 Case side panel 32 External gearing 5 Housing cover 33 internal teeth 6 Housing cover 34 Storage 7 side wall surface 35 Counterweight 8 planar sealing surface 36 retaining ring 9 planar sealing surface 37 screw 10 workspace 38 Mother 11 eccentric 39 outer shell 12 Gas intake 40 Low-pressure side 13 Gas outlet 41 High pressure side 14 Overpressure relief valve 42 Direction of rotation 15 piston base area 43 inflowing gas 16 piston base area 44 escaping gas 17 Piston surface 45 inclined surface 18 Planar sealing channel 46 inclined surface 47 Pressurization direction 19 Planar seal 20 Sealing surface 48 Sealing bridge 21 Shell surface opening 49 radial sealing surface 22 Pressure feed line 23 mouth 50 Sealing web mounting groove 24 cap 51 radial seal receiving channel 25 Corner area 26 radial seal 52 Valve cover 27 Boundary line 53 rotor 54 stator 55 Overflow opening 56 Sealing corner area 57 Contact surface 58 web 59 Direction 60 axis of rotation 61 Point 62 Corner section

Claims

1. A rotary piston compressor (1) for compressing gas, in particular carbon dioxide, wherein the rotary piston compressor (1) has a working housing (2) and a rotary piston (3), and the working housing (2) has a housing side wall (4) and two housing covers (5, 6) arranged on opposing sides of the housing side wall (4), wherein a side wall face (7) of the housing side wall (4) and in each case a planar sealing face (8, 9) of the respective housing cover (5, 6) enclose a working space (10) arranged in the working housing (2), and the rotary piston (3) is rotatably mounted on an eccentric (11) in the working space (10), and the rotary piston compressor (1) has a gas inlet (12) for introducing the gas which is to be compressed into the working space (10) and a gas outlet (13) with a pressure-relief outlet valve (14) for discharging the compressed gas from the working space (10), wherein the rotary piston (3) has two piston base surfaces (15, 16), each facing one of the planar sealing surfaces (8, 9) of the housing covers (5, 6), and a piston lateral surface (17) facing the side wall face (7) of the housing side wall (4), and a planar-seal receiving channel (18) is formed in each of the piston base surfaces (15, 16), and a planar seal (19) is arranged in each of the planar-seal receiving channels (18), wherein the planar seals (19) each have a seal surface (20) for lying against one of the planar sealing surfaces (8, 9) of the housing covers (5, 6), wherein, to press the seal surface (20) of the respective planar seal (19) against the respective planar sealing face (8, 9), lateral-surface openings (21) are formed in the piston lateral surface (17) of the rotary piston (3) which are in pressure-transmitting communication with the respective planar-seal receiving channel (18) by way of pressure feed-through lines (22) which are formed in the interior of the rotary piston (3) and which each open into the respective planar-seal receiving channel (18) on a side of the respective planar seal (19) which faces away from the seal surface (20), and wherein the rotary piston (3) has two or more corner regions (25), characterised in that the planar seals (19), in each case in the corner regions (25) of the rotary piston (3), are sealed off on their side which faces away from the respective seal surface (20) against the planar-seal receiving channel (18) which receives them.

2. A rotary piston compressor (1) according to claim 1, characterised in that the pressure feed-through lines (22) are formed as tubular and / or as a bore and / or as a sequence of bores which open into one another in the interior of the rotary piston (3).

3. A rotary piston compressor (1) according to claim 1 or 2, characterised in that the lateral-surface openings (21) are formed in the piston lateral surface (21) at a distance from the piston base surfaces (15, 16).

4. A rotary piston compressor (1) according to one of claims 1 to 3, characterised in that the planar seals (19) are each injected as injection-moulded parts into the respective planar-seal receiving channel (18), or in that the planar seals (19) are each imprinted as 3D-printed parts into the respective planar-seal receiving channel (18), or in that the planar seals (19) are each pressed as moulded pressed parts into the respective planar-seal receiving channel (18).

5. A rotary piston compressor (1) according to one of claims 1 to 3, characterised in that the planar seals (19) are each prefabricated as inserts and are placed as such in the respective planar-seal receiving channel (18).

6. A rotary piston compressor (1) according to one of claims 1 to 5, characterised in that the pressure feed-through lines (22) in the region of their opening (23) into the respective planar-seal receiving channel (18) are each covered by means of a cap (24).

7. A rotary piston compressor (1) according to one of claims 1 to 6, characterised in that the planar seals (19) are each formed intrinsically in one piece in one of the planar-seal receiving channels (18) in one of the piston base surfaces (15, 16).

8. A rotary piston compressor (1) according to one of claims 1 to 7, characterised in that the side wall face (7) of the housing side wall (4), when viewed in a section plane parallel to the planar sealing surfaces (8, 9) of the housing covers (5, 6), is completely or at least in portions in trochoidal form.

9. A rotary piston compressor (1) according to one of claims 1 to 8, characterised in that one radial seal (26) in each case for sealing off the rotary piston (3) against the side wall face (7) of the housing side wall (4) is arranged in the corner regions (25).

10. A rotary piston compressor (1) according to claim 9, characterised in that the piston base surfaces (15, 16), in the region between two of the corner regions (25) of the rotary piston (3) in each case, are each bounded by a boundary line (27), with the boundary lines (27) each being formed as an envelope of a group of trochoid curves.

11. A rotary piston compressor (1) according to claim 9 or 10, characterised in that in each case an elastic element (28), pointing to the rotary piston (3), for pressing the respective radial seal (26) against the side wall face (7) of the housing side wall (4) is integrally moulded in one piece on the radial seals (26).

12. A rotary piston compressor (1) according to one of claims 9 to 11, characterised in that the planar seals (19) each have contact faces (57) for pressing the respective radial seal (26) against the side wall face (7) of the housing side wall (4).

13. A rotary piston compressor (1) according to one of claims 1 to 12, characterised in that the planar seals (19), and / or the radial seals (26) which may be present, consist of a polymer or of a polymer with a dry lubricant and / or with reinforcing fibres.

14. A rotary piston compressor (1) according to one of claims 1 to 13, characterised in that the housing side wall (4) and the housing covers (5, 6) each have a base body made of an aluminium alloy or of cast iron and a coating (29) applied to the base body to form the side wall face (7) of the housing side wall (4) and the planar sealing surfaces (8, 9) of the housing covers (5, 6), with the coating (29) being a nickel / phosphorus layer or an aluminium oxide layer or a dry-lubricating varnish layer or a combination of at least two of these layers.

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