EP1447566A1 - Rotary-piston machine with rotary coalescing filter - Google Patents

Abstract

The engine (1) has at least two rotary pistons (2, 4) mounted on a drive shaft (2', 4'). A centrifuge (10) is driven by one of the drive shafts (2) in the same direction as this shaft. The shaft on which it is mounted may be the one rotating at the highest revs. It may be formed by a gear wheel (12) with a porous filter sector (14).

Description

Technical field

The present invention relates to a Rotary lobe machine comprising at least two rotary lobes are each mounted on a shaft, at least of which one can be driven in the direction of rotation, a housing in which the Shafts are rotatably mounted and an oil space has, and a centrifuge for generating a negative pressure in the oil room.

State of the art

Rotary piston machines of the type mentioned are in the state generally known in the art. With such Rotary lobe machines are the rotary lobes in a delivery chamber arranged, which must be sealed against an oil space. The shaft of a rotary piston is extended in such a way that it leads through the oil room to the atmosphere and the Drive of the rotary lobe machine is used.

At the passage points of the waves from the pumping room into the Oil seals are usually located around a Prevent oil from entering the delivery chamber. The Seals are especially for gaseous fluids mostly formed in a floating version because of the pressure of the pumping chamber in overpressure operation when the Counteracts oil from the oil room.

Another sealing point is located in the passage area the drive shaft from the oil room to the atmosphere where there is a leak must be prevented by oil. It should be noted that in Oil space usually a certain overpressure (compared to atmospheric pressure).

The contact seals used are due to the Rotation of the rotary lobe shafts causes considerable wear exposed, especially at high speeds. this leads to that the possible operating time of the rotary lobe machine is limited by the durability of the shaft seals.

In addition, it is known in the prior art to Relieving the shaft seals a pressure drop towards that Generate oil space so that the oil due to the pressure drop less tends to get into the atmosphere or the oil space Exit funding area. For this purpose, is usually used the housing of the rotary lobe machine, an additional, separate fed electric motor attached, which a centrifuge for Generation of a vacuum in the oil room drives. The Efficiency of such centrifuges is limited, however the operating speed of suitable electric motors is limited and usually no more than 3000 rpm without gear is, so that the pressure drop to the oil chamber is not is sufficient. In addition, the centrifuges carry the Release air from the oil space into the environment as a result of in the oil particles contained in the air to oil loss what on the one hand increases the maintenance effort of the rotary lobe machine and on the other hand affects the environment. Furthermore is the provision of a separate electric motor from constructive as well as undesirable from an economic perspective.

Summary of the invention

It is an object of the present invention Provide generic rotary lobe machine, the one Oil leaks from the oil room into other machine areas or the atmosphere in a simple and effective way prevented.

This object is accomplished in accordance with the present invention solved a rotary engine according to claim 1.

The present invention is based on the idea of a To achieve pressure drops towards the oil space by the Centrifuge to create a vacuum in the oil room by at least one of the shafts of the rotary lobe machine, especially the drive shaft, and not by one complex additional device or the like driven is.

Accordingly, there exist with the present invention achieved advantages in particular in that the construction the rotary lobe machine is considerably simplified and the Machine can be made more compact. At the same time however, by means of the present invention also a considerable greater pressure drop between the oil chamber and the delivery chamber or the atmosphere because the waves of Rotary lobe machines rotate at significantly higher speeds than the additional drives used so far, such as for example electric motors. Therefore, leakage of Oil from the oil room to other machine areas, in particular the funding room, in a particularly simple and effective manner prevented.

This will not only affect the Pumping chamber effectively excluded by oil, but it will also have significantly lower requirements Sealing between the oil chamber and the delivery chamber or atmosphere posed. In this way the construction of the Rotary piston machine further simplified with regard to sealing the maximum possible speeds of the Rotary lobe machine are increased and the possible Operating time is extended.

Furthermore, thanks to the increased speeds, centrifuges can be used significantly smaller diameter can be used, which the Construction of the machine further simplified. Not least result from all of these achieved with the invention Advantages also considerable economic advantages.

Although the centrifuge has at least one shaft for example by means of a gear or the like can be driven, according to a further development present invention preferred that the centrifuge on one of the shafts is mounted. This is due to the high Speeds of the shafts of the rotary piston machine enables and leads to a very simple and inexpensive Construction of the rotary lobe machine according to the invention. there it is particularly preferred that the centrifuge be on the shaft that is mounted with the highest speed rotates to make the centrifuge as effective as possible with the advantages mentioned above.

According to a development of the present invention Centrifuge formed by an impeller that is porous Has filter section. Thanks to the porous filter section the centrifuge fulfills a dual function by: on the one hand to create a negative pressure in the oil space and on the other hand for the conversion of those passing through the centrifuge Oil particles in oil droplets is used. More specifically, it sucks Centrifuge oil mist, i.e. an oil-air mixture from the oil room and pushes it after passing through the centrifuge out again. The oil mist passes through the porous structure of the filter section, which leads to the oil particles of the Oil mist can be deposited in the pores. Through the Centrifugal force of the centrifuge becomes the most depressed Fog led to the outside, with oil droplets in the pores form that eventually at the exit of the centrifuge are thrown off and are now returned to the oil chamber can be. This way not only the oil inventory of the rotary lobe machine, but also the atmosphere protected against oil pollution.

It is particularly preferred that the filter section consists of metal foam, in particular on the material Nickel or alloys such as nickel / chrome or Nickel / chrome / aluminum based. So the inventors found that this material is highly effective for Is droplet formation, has a high durability and is economically applicable. Particularly cheap The inventors have properties in one Void fraction of the porous filter section of at least 95% found. In addition, it is according to the invention preferred that the porous filter section have a very high Has tensile strength, especially around a reliable one and ensure that the centrifuge operates continuously.

With regard to an advantageous constructive training of Centrifuge it is preferred according to the invention that the porous Filter section is a filter ring that is on an outer Circumference of the impeller is arranged. With this configuration the oil mist from the oil chamber through the centrifuge sucked in and then by rotating in the Centrifugal force acting through the Ejected filter section through.

According to a development of the present invention provided that the rotary lobes in a delivery chamber are arranged, opposite the oil space and / or the Atmosphere using at least one labyrinth seal each Shaft is sealed. The use of a labyrinth seal, i.e. a contactless seal, is in the Rotary piston machine according to the present invention Surprisingly possible because the at least one Shaft driven centrifuge has a sufficient pressure drop generated between the oil space and the delivery chamber. hereby can on the contact seals of the prior art can be dispensed with, and it can be wear-resistant and permanent, non-contact labyrinth seals are used come. This not only improves the durability of the entire rotary piston machine improved, but it will be also significantly higher speeds than previous ones Rotary piston machines possible, for example in the Order of magnitude of 24,000 rpm or higher.

According to the invention, this concept also applies to this trained that the oil room versus the atmosphere is sealed by means of at least one labyrinth seal.

To prevent oil particles from escaping from the According to one principle, further minimizing the rotary lobe machine is Development of the present invention provided that the Rotary lobe machine on the exit side of the centrifuge Has demister. This will remove any residual oil particles, those still in the oil mist emerging from the centrifuge can be included, effectively filtered out and can can also be returned to the oil room. It did shown that the demister and the invention Advantageously complement centrifuge, so that a very extensive removal of the oil particles from which the Centrifuge passing oil mist with the appropriate economic and environmental benefits.

For easy and quick return of oil to the oil room is according to a development of the present invention provided that the housing appropriate facilities, in particular bores, which oil from the Centrifuge and / or the demister in the on the suction side of the Return the centrifuge to the oil chamber.

Although the centrifuge according to the invention with any Speeds of the rotary lobe machine used advantageously , it has been shown that an operating speed of the Centrifuge of at least 6,000 rpm, preferably at least 10,000 rpm is particularly advantageous.

Brief description of the drawings

Fig. 1

shows a schematic sectional view of a Rotary piston machine according to a preferred Embodiment of the present invention;

Fig. 2

shows a partial sectional view of a preferred embodiment of a centrifuge as Part of a rotary lobe machine according to the present invention.

Detailed description of preferred embodiments

Preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Fig. 1 shows a schematic sectional view of a first preferred embodiment of the invention Rotary engine. The rotary lobe machine shown in Fig. 1 1 has two rotary pistons 2, 4, each on a shaft 2 ', 4' are mounted. In addition, the Rotary piston machine 1, a housing 6, in which the shafts 2 ', 4 'are each rotatably supported by means of roller bearings 3. On free end of the shaft 2 'penetrates the wall of the housing 6 and protrudes outside of the housing 6 to be there with to be brought into engagement with a suitable rotary drive. In addition, both shafts 2 ', 4' are each with one Provide gear 28 which are engaged with each other so that a drive torque applied to the shaft 2 ' is transmitted to the shaft 4 '.

The rotary pistons 2, 4 are located together in one Delivery space 16, through which a medium during the Operation of the rotary lobe machine happens. Furthermore is an oil chamber 8 is provided in the housing 6, in which the gears 28 and the rolling bearings 3 for lubrication purposes are located.

Furthermore, the rotary piston machine 1 has a centrifuge 10 on, which is mounted on the shaft 2, on the Drive end opposite end of the shaft 2 '. The Centrifuge 10 is formed by an impeller 12, which as Basic body has a disc with fan ribs. In addition, the impeller 12 has a porous one Filter section 14 in the form of a filter ring on an outer periphery of the impeller 12 is arranged. The Filter section 14 is in the present Embodiment made of metal foam, which has a void portion of at least 95% and has a high tensile strength. Such metal foams, preferably on the material Nickel or alloys such as nickel / chrome or Nickel / chrome / aluminum based, for example at Recemat International BV, 2920 AC Krimpen aan den Ijssel, Netherlands in various embodiments available. However, it goes without saying that though metal foams have proven to be particularly advantageous, also other suitable materials than porous filter sections can be used.

Between the delivery chamber 16 and the oil chamber 8 are for each Shaft 2 ', 4' on both sides of the rotary lobes 2, 4 a first Labyrinth seal 18 and a second labyrinth seal 20 provided with its inner circumference the outer circumference of the waves 2 ', 4' facing. With the labyrinth seals 18, 20 are therefore non-contact seals.

They ensure that oil penetrates from the oil space 8 in the delivery chamber 16 is safely avoided. Furthermore is between each of the labyrinth seals 18 and 20 so-called neutral space provided that matches the atmosphere communicated.

Furthermore, the oil space 8 is relative to the atmosphere sealed at least one labyrinth seal, which in the Area of the drive shaft 2 ′ emerging from the housing 6 faces the shaft 2 ', so that the oil leaks out the oil space 8 is avoided in the atmosphere.

On the exit side of the centrifuge 10, the Rotary piston machine 1 also has a demister 24.

Fig. 2 shows a partial sectional view of a Centrifuge 10 according to the invention, which compared to that in Fig. 1st centrifuge shown is slightly modified. In the in Fig. 2 embodiment shown is the centrifuge 10 in a separate housing section 6 'mounted next to the Centrifuge 10 also receives the demister 24. The Demister 24 is arranged in Fig. 2 immediately after the centrifuge 10, and enclosed by two grids 24 '. Below the Centrifuge 10 and the demister 24 are each a bore 26 provided for the return of condensed oil particles serves in the oil space 8, for example not in Fig. 2 shown lines or channels.

The operation of the rotary lobe machine according to the invention takes place as follows. When applying one Drive torque on the drive shaft 2 'rotate the Rotary pistons 2, 4 synchronously with a certain speed, the for example in the range from 6,000 to 24,000 rpm can. The centrifuge also rotates together with the shaft 2 ' 10 and continuously sucks oil mist out of the oil space 8, i.e. an air-oil mixture. Due to the suction effect of the Centrifuge 10 is in the oil chamber 8 compared to Atmosphere creates a vacuum that works in conjunction with the labyrinth seals 18, 20 and 22 leak oil from the oil chamber 8 into the delivery chamber 16 or the atmosphere prevented.

The oil mist entering the centrifuge 10 is due to radial centrifugal force in the centrifuge flung outward to then pass through the porous Section 14 of the impeller 10 to pass. The Oil mist in the pores of the porous section 14 dejected. The downed fog is through the Centrifugal force led outward, being in the pores Form drops on the outer diameter of the centrifuge 10 or the porous filter section 14 are thrown off. The droplets thrown off the centrifuge can then for example using gravity in the oil space 8 are returned, for example through the bores 26 and corresponding lines.

The fluid flow emerging from the centrifuge occurs then in the demister 24, where any residual shares of oil particles further reduced and also over the Bores 26 or the like are returned to the oil space can be.

Claims (12)

Rotary piston machine (1) comprising: at least two rotary pistons (2, 4), each mounted on a shaft (2 ', 4'), of which at least one (2 ') can be driven in the direction of rotation, a housing (6) in which the shafts (2 ', 4') are each rotatably mounted and which has an oil chamber (8), a centrifuge (10) for generating a negative pressure in the oil space (8), characterized in that
the centrifuge (10) is driven in the direction of rotation by at least one of the shafts (2 ', 4'), in particular a drive shaft (2 '). Rotary piston machine according to claim 1, characterized in that the centrifuge (10) is mounted on one of the shafts (2 ', 4'), in particular on that shaft which rotates at the highest speed. Rotary piston machine according to claim 1 or 2, characterized in that the centrifuge (10) is formed by an impeller (12) which has a porous filter section (14). Rotary piston machine according to claim 3, characterized in that the porous filter section (14) consists of metal foam, which is preferably based on nickel or alloys such as nickel / chromium or nickel / chromium / aluminum. Rotary piston machine according to claim 3 or 4, characterized in that the porous filter section (14) has a void fraction of at least 95%. Rotary piston machine according to one of claims 3 to 5, characterized in that the porous filter section (14) has a very high tensile strength. Rotary piston machine according to one of claims 3 to 6, characterized in that the porous filter section (14) is a filter ring which is arranged on an outer circumference of the impeller (12). Rotary piston machine according to one of the preceding claims, characterized in that the rotary pistons (2, 4) are arranged in a delivery chamber (16) which is opposite the oil chamber (8) and / or the atmosphere by means of at least one labyrinth seal (18, 20) per shaft is sealed. Rotary piston machine according to one of the preceding claims, characterized in that the oil space (8) is sealed off from the atmosphere by means of at least one labyrinth seal (22). Rotary piston machine according to one of the preceding claims, characterized in that it has a demister (24) on the outlet side of the centrifuge (10). Rotary piston machine according to one of the preceding claims, characterized in that the housing (6) devices, in particular bores (26), for returning oil from the centrifuge (10) and / or the demister (24) into the on the suction side of the centrifuge ( 10) lying oil chamber (8). Rotary piston machine according to one of the preceding claims, characterized in that the operating speed of the centrifuge (10) is at least 6,000 rpm, preferably at least 10,000 rpm.

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