WO2015063252A1

WO2015063252A1 - Positive displacement blower with a sealing system

Info

Publication number: WO2015063252A1
Application number: PCT/EP2014/073422
Authority: WO
Inventors: Hubert Hamm
Original assignee: ENVA Systems GmbH
Priority date: 2013-10-31
Filing date: 2014-10-31
Publication date: 2015-05-07
Also published as: DE102013112024A1

Abstract

Device (1) for the conversion of energy contained in a fluid, with a housing (2) which comprises a working chamber (7), at least one oil chamber (21), an inlet opening (5) and an outlet opening (6), at least two rotors (8) rotatably mounted in the housing (2), which rotors each have at least two vanes (10), wherein the rotational axes (9) of the rotors (8) are arranged axis parallel to each other, and wherein the rotors (8) can be operated counter rotating and at the same speed. In order that the device (1) is suitable as a fluid-flow machine for obtaining energy, in particular as a turbine, at least one sealing system (20) is arranged between the working chamber (7) and the oil chamber (21).

Description

Positive displacement blower with a sealing system

The invention relates to a device for converting energy contained in a fluid with a housing having a working space, at least one oil chamber, an inlet opening and an outlet opening, at least two rotatably mounted in the housing rotors, each having at least two wings, wherein the axes of rotation the rotors are arranged axially parallel to each other, and wherein the rotors are operated in opposite directions and at the same speed.

Numerous devices with a housing, which have a working space, at least one oil chamber, an inlet opening and a housing, are known from the prior art

Outlet opening, with at least two rotatably mounted rotors in the housing, each having at least two wings, wherein the axes of rotation of the rotors are arranged axially parallel to each other, and wherein the rotors in opposite directions and at the same speed are operable known. Such devices are commonly used as pumps for conveying gases or liquids and are also known under the designations "rotary pump" or "rotary piston blower". A typical rotary piston engine is known for example from DE 100 37 966 Cl. Known rotary engines are usually well suited for the conveyance of gases or liquids. For this purpose, rotary engines are often driven by a motor. The advantages of rotary-piston engines are, for example, their high flow rate and - in contrast to reciprocating engines - their low-vibration operation, but the disadvantage of rotary-piston engines is that they are usually only very small

Pressure difference between fluid inlet and fluid outlet can reach. As a result of the small pressure differences arise in rotary engines regularly no high temperature differences. Rotary engines are therefore indeed suitable for conveying fluids, but less for compression or decompression of fluids.

Nor are known rotary engines as turbomachines, which are not used for the promotion of fluids, but the one

flowing fluid to deprive energy to convert it into mechanical and / or electrical energy. In other words

Rotary engines previously used as an energy consuming pump, but not as energy-emitting turbine. This is mainly because when operating turbines for thermodynamic reasons, a high temperature and / or pressure difference between inlet and outlet is required in order to achieve high efficiency. As mentioned earlier, known

However, rotary engines just not on high pressure and

Temperature differences designed. In particular, the seals of known rotary engines are not designed for high pressure and temperature differences.

The invention is therefore based on the object, the device described in the introduction and previously described in such a way and further develop that it is suitable as a turbomachine for energy production, especially as a turbine.

In a device according to the preamble of claim 1, this object is achieved in that between the working space and the oil space at least one sealing system is arranged. A device according to the invention is initially distinguished by a housing which has a working space, at least one oil space, an inlet opening and an outlet opening. Preferably, both the inlet opening and the outlet opening are connected to the working space, so that a fluid through the

Inlet opening can enter the working space and then escape through the outlet opening again from the device. The at least one oil chamber, however, is preferably separated from the working space. It can be provided that the housing comprises a plurality of oil chambers. For example, two oil chambers may be provided, which are arranged at the ends of the rotors to lubricate rolling bearings arranged there. The housing may be formed in several parts. A device according to the invention is further characterized by at least two rotors rotatably mounted in the housing, each having at least two wings. The axes of rotation of the rotors are arranged axially parallel to one another and the rotors can be operated in opposite directions and at the same speed. Preferably, the rotors are synchronized by gears, in particular by spur gears with straight teeth. The synchronization by spur gears has the advantage that a very precise synchronization of the rotors can be achieved, whereby the wings of the rotors can very precisely mesh. In addition, a reversal of the direction of rotation is achieved automatically by gears. Due to the straight teeth axial forces are avoided, so that, for example, the use of cylindrical roller bearings for mounting the rotors is possible.

In order to use the device even at high pressure and temperature differences, a particularly good seal between the working space and the oil chamber is required. For lubricant that has been filled into the oil chamber, for example for the lubrication of rolling bearings, must not enter the working space and contaminate the working medium flowing through the working space. To prevent this, the invention provides that at least one sealing system is arranged between the working space and the oil space. A sealing system is understood to mean the combination of at least two sealing elements. The sealing elements can be supplemented by other elements, for example, for positioning the

Serve sealing elements. Preferably, such a sealing system is arranged at each connection point between an oil chamber and the working space, so that a plurality of oil chambers and / or a plurality of connection points per oil chamber a total of several sealing systems can be provided. According to one embodiment of the invention it is provided that the sealing system comprises at least one stuffing box seal. A stuffing box gasket serves the contacting sealing of a space lying between two relatively rotating parts; it is therefore a dynamic, touching seal. Stuffing box gaskets are particularly simple and robust: The - often annular - sealing element is pushed into an annular space between the shaft and hub ("stuffed") and compressed in the axial direction, so that it expands in the radial direction and both with the shaft and Preferably, the gland packing is made of a braid of carbon fibers or a braid of synthetic fibers, such as PTFE (polytetrafluoroethylene) or aramid fibers, or combinations of these materials are possible.

For this embodiment, it is further proposed that the stuffing box seal has a trapezoidal cross-section. The cross section should be trapezoidal when not installed. A seal with a rectangular cross-section changes the shape of its cross-sectional area when it is placed in a ring around a shaft to be sealed. The change is such that the seal becomes narrower in its radially outer region due to the expansion occurring there, while the seal widens in its radially inner region due to the compression occurring there. Such a seal has a very uneven pressure distribution when installed and therefore an unsatisfactory sealing effect. Trapezoidal cross sections, the described change of

Cross-sectional area can be compensated so that when installed a nearly rectangular, in particular square cross-sectional area is achieved. This results in a particularly advantageous pressure distribution and thus a particularly reliable seal. The trapezoidal cross-section may be wider in the non-installed state, for example in its radially outer region than in its radially inner region.

Another teaching of the invention provides that the sealing system comprises a lantern ring. A lantern ring serves the purpose of removing leaks from the sealing system or adjacent sealing elements lubricating or cooling liquid supply. This can take place via at least one channel provided in the housing, before the outlet of which the lantern ring is mounted. In addition, in the housing in the region of the lantern ring, a circumferential groove for distributing the materials to be supplied or discharged can be provided. Preferably, the lantern ring is made of plastic, for example made of PTFE (polytetrafluoroethylene).

For this teaching is further proposed that the lantern ring is arranged between two stuffing box seals. By virtue of this arrangement, the lantern ring can supply two adjacent seals simultaneously with lubricating or cooling liquid or simultaneously discharge leaks from two adjacent seals. This has the advantage that it is possible to dispense with the drilling of an additional series of channels.

According to a further embodiment of the invention, it is provided that the sealing system comprises a radial shaft sealing ring. A radial shaft sealing ring is also a dynamic, contacting sealing element for sealing a space between relatively rotating parts, for example between a shaft and a hub. Radial shaft seals have a sealing lip, which is pressed by a rotating spring radially on the shaft. In this way, a particularly reliable seal is achieved.

For this training is further proposed that the radial shaft seal is disposed axially outside of the gland seal. By this arrangement it is achieved that the radial shaft sealing ring is arranged closer to the oil chamber than the stuffing box seal. The radial shaft sealing ring is preferably arranged directly on the oil space. This has the advantage that the radial shaft seal with its open side can face the oil chamber. In this way, the increased internal pressure of the oil chamber can act on the radial shaft seal and press the sealing lip particularly firmly on the shaft and thus increase the sealing effect. According to a further embodiment of the invention, a bushing is provided on the stuffing box seal and / or the lantern ring and / or the

Radial shaft seal are arranged. The liner can - for example by a press fit - be firmly connected to the rotor shaft and thus represent a running surface for the seals. Due to the relative movement between the liner and the seals of the sealing system are very demanding

Surface quality of the bushing provided. However, the high surface quality can be achieved more easily on the small bushing than on the shaft itself. In addition, the liners protect the shaft against wear and can be easily replaced if the wear is too high.

In a further embodiment of the invention, a sealing ring housing is provided, in which the stuffing box seal and / or the lantern ring and / or the radial shaft sealing ring are arranged. Due to the sealing ring housing is a safe and accurate

Positioning of the components of the sealing system, such as the

Radial shaft seal or the stuffing box seal achieved. In particular, the sealing ring housing can assume an adapter function and sealing elements

Position different size between shaft and hub. The

Sealing ring housing may have at least one channel and additionally a circumferential groove for supplying a lantern ring.

The device described above and its advantageous developments are particularly suitable for use as a turbine and in particular for driving a generator for generating electrical energy. Due to the structural features of the device described in detail above, it is suitable for high pressure and temperature differences and thus for use as a turbine. Ideally, the mechanical energy of the rotating rotors is converted by a generator into electrical energy. For example, the device can be used to generate energy in steam or gas networks, since such networks usually have different pressure levels anyway and therefore a reduction of the pressure must be made in some places. In just these places can the fluid be passed through the device described above and the reduction made by the pressure to be used for energy. Accordingly, the device can be operated as a relaxation device, which is adapted to a pressure of a flowing into the inlet opening of the device described above fluid, which for example a gaseous

Can represent working means to reduce and thereby convert at least some of the energy released in the pressure reduction by relaxation of the fluid into mechanical energy. In this use, as

Working media both water (especially in the form of water vapor), as well as organic media can be used. When using water as a medium, pressure differences of up to 8 bar and temperatures of about 200 ° C have been found to be suitable. With organic media, good results were achieved with pressure differences of up to 5 bar and temperatures of about 160 ° C. The use of organic media, for example, in the context of OCR processes ("Organic Rankine Cycle") take place.

The device described above can be used, for example, as a rotary piston machine to relax the fluid, wherein the rotary piston machine, which can also be referred to as Roots blower or Roots blower works on the principle of external compression, so that the fluid no relaxation by volume change in the closed working chamber of the

Rotary piston machine experiences, but is ejected against the system back pressure. The relaxation of the working fluid therefore takes place in the rotary piston blower, for example, by the outlet of the fluid at the outlet opening of the device.

The device described above and its advantageous developments can be used at high pressure differences. Between the inlet opening and the outlet opening of the device, a pressure difference of at least 5 bar, in particular of at least 10 bar may be present. Even with pressure differences of 15 bar, the described device has worked reliably. A further embodiment of the invention provides for the use of the device described above in one of the following networks: steam network,

Carbonic acid network, compressed air network, and natural gas network.

Accordingly, the fluid may, for example, steam, carbonic acid,

Compressed air or natural gas.

The invention will now be described with reference to a preferred one

Embodiment illustrative drawing explained in more detail. In the drawing show

Fig. 1 shows a device according to the invention for the conversion of in one

2 shows the device according to the invention from FIG. 1 in a sectional view

Representation along the drawn in Fig. 1 section plane II-II, and

Fig. 3 is a schematic representation of the operation of a

Device according to the invention for converting energy contained in a fluid.

1 shows a device 1 according to the invention for converting energy contained in a fluid in a perspective view. The device has a housing 2, of which in Fig. 1, only one half is shown. The housing 2 can be divided into two parts along a vertically extending parting plane 3. The parting plane 3 has a plurality of through holes 4, via which the two halves of the housing 2 - can be connected to each other - such as by screws.

In addition, the two parts of the housing 2 can be glued together to increase the tightness of the housing 2 in the region of the parting plane 3. The housing 2 has on its upper side an inlet opening 5 and on its underside a

Outlet opening 6 (hidden in Fig. 1) for inflow or outflow of a fluid. in the In its interior, the housing 2 has a working space 7, which has the shape of two overlapping circles in cross-section. In the working space 7, two rotors 8 are arranged, whose axes of rotation 9 extend axially parallel to each other. Each of the rotors 8 shown in FIG. 1 and so far preferred has three wings 10. Each of the wings 10 is at its radially outer region with a

Sealing strip 11 equipped. The sealing strip 11 contacts the inner wall of the working space 7 or the surface of the respective other rotor 8 during a rotation of the rotors 8.

In Fig. 1 it can be seen that one of the two rotors 8 has at one of its ends a drive shaft 12. The drive shaft 12 can be led out of the housing 2 through an opening, not shown in FIG. 1, in order to drive a generator there (not shown in FIG. 1). The connection to the generator can be generated via a tongue and groove connection, for which purpose the drive shaft 12 has a groove 13. The rotors 8 have at both ends adjacent to the wings 10 cylindrical portions 14. The wings 10 of the rotors 8 have end faces 15, which are flat surfaces which run perpendicular to the axis of rotation 9 of the respective rotor 8. The cylindrical portions 14 serve to support the rotors 8 in the housing 2. The housing 2 also has an oil filler neck 16 with a vent screw 17 and a sight glass 18 for checking the oil level (only shown in Fig. 2).

Fig. 2 shows the inventive device 1 of FIG. 1 in cut

Representation along the drawn in Fig. 1 section plane II-II. Fig. 2 thus allows a view from above into the housing 2 inside. The areas of the device 1 already described in connection with FIG. 1 are shown in FIG. 2 with corresponding ones

Provided with reference numerals. The housing 2 is formed in four parts in Fig. 2 and comprises the two connected to the parting plane 3 parts 2.1 and 2.2 and the two end-mounted parts 2.3 and 2.4. Both rotors 8 are mounted side by side in the housing 2, wherein the axes of rotation 9 of the two rotors 8 are arranged axially parallel. The rotors 8 are rotatably supported in the housing 2 via bearings 19. The bearings 19 are on both sides of the wings 10 on the cylindrical portions fourteenth arranged the rotors 8 and are supported on the housing 2. Preferably, the bearings 19 are cylindrical roller bearings. For protection

Impurities of the bearings 19 can axially outside of the bearings 19th

Centrifugal discs to be mounted on the rotors 8.

In addition to each bearing 19, a sealing system 20 is arranged. By the sealing system 20 is formed in the housing 2 on both sides of the working space 7 each have an oil chamber 21 which contains 19 oil for lubrication of the bearing. The sealing system 20 prevents oil from entering one of the oil chambers 21 in the working space 7. In the device 1 shown in Fig. 2, the sealing system 20 comprises a radial shaft seal 22, a first stuffing box seal 23, a second stuffing box seal 24 and a lantern ring 25. The radial shaft seal 22 is - viewed from the center of the rotor 8 - arranged axially outward. In the axial direction further inside follows the first stuffing box seal 23. It follows the lantern ring 25. In the axial direction completely inside is the second

Stuffing box seal 24 is arranged. The first stuffing box seal 23 and the second stuffing box seal 24 have a trapezoidal cross-section, which, however, can not be recognized in the installed state (shown in FIG. 2). The lantern ring 25 is connected to at least one channel 26 drilled in the housing, via which leaks can be removed and lubricants or coolants can be supplied.

Furthermore, a bushing 27 is provided, on which the radial shaft sealing ring 22, the two stuffing box seals 23, 24 and the lantern ring 25 are mounted. In addition - unlike in Fig. 2 shown - and the bearing 19 may be mounted on the bushing 27. The bushing 27 is connected, for example by a press fit, fixed to the rotor 8. Further, a sealing ring housing 28 is provided, in which the radial shaft seal 22, the two stuffing box seals 23, 24 and the

Lantern ring 25 are mounted. The bushing 27 is thus arranged radially within the sealing system 20, while the sealing ring housing 28 is arranged radially outside of the sealing system 20. Between the end faces 15 of the rotors 8 and the immediately adjacent components, in this case arranged next to the sealing systems 20 Housing end faces, an axial clearance 29 is formed. As axial play 29 of the smallest free space in the axial direction between the end face of the wing 10 and the housing end part is called. An axial play 29 has proved particularly advantageous in the range between 0.01 mm and 0.5 mm, in particular between 0.05 mm and 0.2 mm. In a corresponding manner, a radial clearance 30 is formed between the blades 10 of the rotors 8 and the inner wall of the working space 7. When

Radial play 30 is the smallest free space between the rotor 8 and the inner wall of the working space 7 in the radial direction. This may be the distance between the wing 10 and the inner wall or - if the wings 10 have sealing strips 11 - the distance between the sealing strips 11 and the inner wall. As a particularly advantageous radial play 30 has been found in the range between 0.01 mm and 0.2 mm, in particular between 0.05 mm and 0.1 mm.

The drive shaft 12 of the rotor 8 shown in Fig. 2 above is led out through an opening 31 of the housing. In the region of this opening 31, a seal 32 is arranged, which seals the housing 2 relative to the rotatably mounted drive shaft 12. The seal 32 may be a

Radial shaft seal deal, which is optionally supplemented with a retaining ring. At the end opposite the drive shaft 12, each rotor 8 has a gear 33. The two gears 33 are identically constructed and interlock, so that both rotors 8 are operated at the same speed and opposite direction of rotation. By the gears 33 so both rotors 8 are synchronized.

Finally, FIG. 3 shows a schematic representation of the mode of operation of a device 1 according to the invention for converting energy contained in a fluid. Again, those areas of the device 1, which are already in

In connection with FIG. 1 and / or FIG. 2 have been described, provided with corresponding reference numerals. In operation, the rotors 8 of the device 1 rotate as shown by the arrows in FIG. A fluid, ie a gas, a vapor or a liquid, is pressed into the housing 2 due to a pressure difference through the inlet opening 5 and causes the rotors 8 to rotate. In the further Course is the fluid between two adjacent blades 10 of the rotor 8 enclosed further pressed by the housing 2. Finally, the fluid is pushed out of the housing 2 through the outlet opening 6.

LIST OF REFERENCE NUMBERS

1: device

2: housing

2.1, 2.2, 2.3, 2.4: Housing part

3: parting plane

4: through hole

5: entrance opening

6: outlet

7: workspace

8: rotor

9: rotation axis

10: wings

11: sealing strip

12: drive shaft

13: groove

14: cylindrical area

15: face

16: Oil filler neck

17: Bleed screw

18: sight glass

19: camp

20: sealing system

21: Oil room

22: Radial shaft seal

23: first stuffing box gasket

24: second stuffing box gasket

25: lantern ring

26: channel

27: bushing

28: Sealing ring housing

29: axial play

30: radial play

31: opening

32: seal

33: gear

Claims

claims

Device (1) for converting energy contained in a fluid with

- A housing (2) having a working space (7), at least one oil chamber (21), an inlet opening (5) and an outlet opening (6),

at least two rotors (8) rotatably mounted in the housing (2) and each having at least two wings (10),

- Wherein the axes of rotation (9) of the rotors (8) axially parallel to each other

are arranged, and

- Wherein the rotors (8) in opposite directions and at the same speed are operable, characterized in that

between the working space (7) and the oil space (21) at least one

Sealing system (20) is arranged.

Device according to claim 1,

characterized in that

the sealing system (20) comprises at least one stuffing box seal (23, 24).

Device according to claim 2,

characterized in that

the gland packing (23, 24) has a trapezoidal cross-section.

Device according to one of claims 1 to 3,

characterized in that

the sealing system (20) comprises a lantern ring (25).

Device according to claim 4,

characterized in that the lantern ring (25) is arranged between two stuffing box seals (23, 24)

6. Device according to one of claims 1 to 5,

characterized in that

the sealing system (20) comprises a radial shaft sealing ring (22).

7. Apparatus according to claim 6,

characterized in that

the radial shaft sealing ring (22) is arranged axially outside the gland packing (23, 24).

8. Device according to one of claims 1 to 7,

geke nzeichnet by

a bushing (27) on which the gland packing (23, 24) and / or the lantern ring (25) and / or the radial shaft sealing ring (22) are arranged.

9. Device according to one of claims 1 to 8,

marked by

a sealing ring housing (28) in which the stuffing box seal (23, 24) and / or the lantern ring (25) and / or the radial shaft sealing ring (22) are arranged.

10. Device according to one of claims 1 to 9,

characterized in that

the housing (2) has an opening (31) for passing through a drive shaft (12), and that the opening (31) is sealed by a seal (32).

11. Use of a device (1) according to one of claims 1 to 10 as

Turbine.

12. Use according to claim 11 for driving a generator for generating electrical energy.

13. Use according to claim 11 or 12, wherein water or organic media are used as the working medium.

14. Use according to any one of claims 11 to 13, wherein between the

Inlet opening (5) and the outlet opening (6) of the device (1) a pressure difference of at least 5 bar, in particular of at least 10 bar is present.

Use according to any one of claims 11 to 14, wherein the device is operated on one of the following networks:

- steam network,

Carbonated network

Compressed air network, and

Natural gas network.