ROTARY LOCK

Description

FIELD OF THE INVENTION

[0001] The invention relates to a rotary valve for bulk material according to the features of the preamble of claim 1. Such a rotary valve is known, for example, from patent DE 37 42 522 C1. The bulk material can be shotcrete, a powdery or granular material, or a viscous material. The bulk material enters the rotary valve via a feed device, such as a silo or tank, or via a downpipe or a line. When the rotary valve is operated, the bulk material is conveyed and leaves the rotary valve on the outlet side. The rotary valve comprises a rotary chamber and a rotary wheel arranged in the rotary chamber. The rotary wheel is connected in a rotationally fixed manner to a drive shaft. The rotary wheel comprises a plurality of webs or cell walls that delimit the cells. For example, the rotary wheel can form 14 cells. Optionally, more than 14 cells or fewer than 14 cells can be provided.

[0002] The rotary valve further comprises at least one cover that delimits the rotary valve chamber. Preferably, two covers can be provided, with the rotary valve chamber being cylindrical or nearly cylindrical in shape. The two covers then form the end faces of the (generally cylindrical) rotary valve. The rotary valve chamber has a nearly cylindrical shape, for example, if a cone with a small (opening) angle is provided in the rotary valve chamber to facilitate the assembly / disassembly of the rotary valve, cover, and rotary valve chamber (demolition cone). Sealing means for tightly connecting the cover(s) to the rotary valve chamber are provided between the cover or between the covers and the rotary valve chamber, or between the cover(s) and the rotary valve. TECHNOLOGICAL BACKGROUND

[0003] Rotary valves have proven effective for conveying powdery or viscous materials, especially shotcrete. The resulting forces and torques place comparatively high mechanical stress on individual components of the valve. This is due, among other things, to the weight and properties of the bulk material, such as its grain size and flow characteristics. If high conveying speeds or rates are required, the valve components are sometimes subjected to considerable stress.

[0004] It has been shown that a rotary valve can be operated more effectively if the cell is subjected to a discharge pressure on the outlet side of the valve, so that the cell is blown empty or almost empty as a result of the discharge pressure. The resulting pressure gradients within the valve assembly increase the material stress on the valve components, which impairs the service life or operating time of the valve. PRESENTATION OF THE INVENTION

[0005] Against this background, the object of the present invention is to increase the service life and maintenance intervals of a rotary valve described above, with particular emphasis on reducing the material stress on the rotary valve components. This object is achieved by a rotary valve according to claim 1. Preferably, at least one cavity arranged in or on the rotary valve and inaccessible to the bulk material can be subjected to a cavity overpressure using the pressure device. The pressure device generates a gas (over)pressure at least in some areas, which counteracts or compensates for internal forces and moments, for example caused by the conveying pressure, in the valve in a stabilizing manner. The formation of a pressure gradient inside the valve is thereby avoided, at least in some areas.

[0006] The cavity can be formed as at least one recess arranged on the cellular wheel; due to symmetry considerations, multiple recesses can be provided. For example, one recess can be provided on each end face of the generally cylindrical cellular wheel chamber. Multiple recesses can also be provided on each end face.

[0007] Ideally, the gas pressure inside the rotary valve is essentially the same as the discharge pressure, so that almost all components are exposed to one pressure instead of several different ones.

[0008] If the cellular wheel comprises a shaft receptacle formed as a central opening extending in the longitudinal direction, in which the drive shaft is arranged in a rotationally fixed manner, it can be provided that the cavity borders the central opening and thus the shaft at least in sections. Alternatively or cumulatively, it can be provided that the cover or one of the covers delimits the cavity at least in sections. It can also be provided that each of several (two) covers delimits a partial area of the cavity.

[0009] Preferably, the cavity can form at least one annular space which borders the drive shaft completely along at least one section of the drive shaft. Particularly preferably, two annular spaces are provided which border the drive shaft in the region of the covers and are delimited in sections by the covers. By subjecting the annular space or spaces to a cavity overpressure, a circumferential cavity overpressure is applied around one or more sub-sections of the drive shaft, whereby a pressure sleeve formed from the overpressure gas is applied to the drive shaft. The overpressure, which in particular borders the shaft completely, counteracts pressure-induced deflection of the shaft, thereby reducing wear on the shaft and the wear on the cellular wheel arranged on the shaft. The lock can therefore be operated for longer without maintenance interruptions.

[0010] In particular, one-sided mechanical stress on the drive shaft, such as that caused by cells with different filling levels ("full at the top, empty at the bottom") or by overpressure prevailing in a cell (on the outlet side), for example, to blow out the bulk material, is significantly reduced by the cavity overpressure. The reduced stress (deflection) on the drive shaft also protects the cellular wheel: In particular, those parts of the cellular wheel walls that border the cells on the periphery and that may have (direct) contact with the cellular wheel chamber are more evenly pressed against the periphery of the cellular wheel chamber due to the overpressure-induced reduction in one-sided loading on the drive shaft, which reduces wear on the cellular wheel. This also has a positive effect on the service life of the lock device.

[0011] According to the invention, a pressure device is also provided with which the sealing agent and / or a sealing agent chamber surrounding the sealing agent can be subjected to a sealant overpressure. Sealants regularly generate a contact pressure on one or more sealing surfaces against which the sealing agent rests. The contact pressure can be generated by the restoring forces of a deformed or deformed sealing agent (for example, as a result of pressing or squeezing a seal made of a yielding material such as plastic or rubber) or by spring elements that exert pressure on the sealing agent. The pressure device according to the invention increases this contact pressure by a contribution of the sealant overpressure, which reinforces the contact pressure and thus the sealing effect. The effect of the sealing agent is thereby improved, so that interruption of operation of the lock due to leaks or the need to replace a seal is avoided.The sealant pressure ultimately reduces the material stress on the rotary valve components. According to the invention, the sealant can be pressed (more strongly) against the sealant contact surface assigned to the sealant by the sealant overpressure. The contact surface is the surface against which the sealant rests. The contact surface can be arranged on one or more lock components; the contact surface can also comprise several surface areas, with a first surface area being arranged on a first component and a second surface area on a second component. The sealant can comprise a pressure surface onto which a force can be exerted by the sealant overpressure, which force increases the contact force of the sealant. The sealant is arranged in an annular sealant groove, wherein the sealant groove can be subjected to the sealant overpressure.The sealant groove is arranged in the cover and on a sleeve arranged in the cell wheel chamber, in sealing contact with the cell wheel and adjacent to the cover.

[0012] The sealing means comprises a main seal and two additional seals, wherein the first additional seal is arranged on the sleeve and the second additional seal is arranged in the sealing means chamber in the region of the cover.

[0013] Alternatively or cumulatively, mechanical clamping devices can be provided to press the seal against the relevant seal contact surface(s). These clamping devices provide a variable contact force that can be adjusted by the user if necessary. A self-adjusting clamping device can also be provided, which always provides a contact force that is appropriate to the requirements.

[0014] A rotary valve can be provided that comprises a first pressure device for generating the cavity overpressure described above, as well as a second pressure device for generating the sealing overpressure, also described above. According to a preferred embodiment of the rotary valve, both the cavity overpressure and the sealant overpressure can be generated by a pressure device. A valve or valve block can be provided, through which the (partial) pressures for the sealant overpressure and / or for the cavity overpressure can be switched on and / or off.

[0015] A particular advantage arises if the pressure device (also or primarily) generates a conveying pressure, whereby a cell of the rotary valve can be subjected to the conveying pressure, and whereby the conveying pressure causes the bulk material to be conveyed out of the rotary valve. The pressure device thus generates, on the one hand, the conveying pressure for effectively emptying the outlet side of the valve and, on the other hand, the cavity overpressure and / or the sealant overpressure. Here, too, a valve / valve block can be provided in order to form the total pressure of the pressure device onto the (partial) pressures of conveying pressure, cavity overpressure and sealant overpressure. At least one pressure reducer can be provided, for example so that the cavity overpressure and / or the sealant overpressure is higher than the conveying pressure within the rotary valve chamber.At least one channel can be provided, for example, in the housing of the rotary valve, which is fluidically connected to the pressure device and can be used to apply excess pressure to the cavity and / or the sealant groove. Multiple channels can also be provided, with one channel, for example, being fluidically connected to the pressure device and another channel to the sealant chamber.

[0016] For example, the pressure generator (pressure device) that generates the discharge pressure can include a bypass that pressurizes the channel of the pressure device with gas pressure (air pressure), so that cavity overpressure / sealant overpressure are available. To ensure that the cavity overpressure and / or the sealant overpressure together or each are higher than the discharge pressure, a line to the discharge pressure inlet or the discharge pressure inlet can include a pressure reducer.

[0017] To further reduce wear, a sleeve can be provided in the cellular wheel chamber, which is in sealing contact with the cellular wheel, in particular with the wheel's webs. The sleeve can be made of a plastic, metal, or ceramic material. A gap can be provided between the sleeve and the web, with the gap being less than 0.3 mm, preferably 0.1 mm.

[0018] The cavity overpressure and / or the sealant overpressure and / or the delivery pressure can be controlled and / or regulated, in particular, can be controlled and regulated. Thus, using suitable valves and fluid-mechanical parts and components, an overpressure in a pressure range from zero to a maximum pressure provided by a pressure generator can be selected and distributed to the cavity overpressure channel and / or the sealant overpressure channel.

[0019] To increase the service life or operating time, a pressure generation method can also be provided, with which a cavity overpressure and / or a sealant overpressure and / or a delivery pressure are generated. The sum of the cavity overpressure and delivery pressure, or the sum of the sealant overpressure and delivery pressure, or the sum of the cavity overpressure and sealant overpressure and delivery pressure, is at most as large as the maximum pressure generated by the pressure generation. By controlling / regulating one or more valves, in particular those assigned to the channel(s), each partial pressure (cavity overpressure, sealant overpressure, delivery pressure) can be individually adjusted.Preferably, the partial pressures (cavity overpressure and / or sealant overpressure) are set so that they are higher than the discharge pressure partial pressure, whereby the discharge pressure can be compensated at least partially within the lock, reducing the material stress on the shaft and cellular wheel. The discharge pressure can be less than 8 bar, for example, 6 bar or between 1 and 3 bar. The sealant overpressure / cavity overpressure can be above 3 bar, in particular above 6 bar.

[0020] The aforementioned components to be used according to the invention as well as those claimed and described in the exemplary embodiments are not subject to any special exceptional conditions in terms of their size, shape, material selection and technical conception, so that the selection criteria known in the field of application can be applied without restriction.

[0021] Further details, features, and advantages of the subject matter of the invention emerge from the dependent claims, as well as from the following description and the accompanying drawing, which illustrates an exemplary embodiment of a rotary valve. Individual features of the claims or embodiments can also be combined with other features of other claims and embodiments. The scope of the invention is defined by the claims. BRIEF DESCRIPTION OF THE DRAWING

[0022] In the drawing show Fig. 1a perspective view of a rotary valve, Fig. 2A, Bside view and bottom view of the rotary valve according to Fig. 1 , Fig. 3A,B schematic sectional views of various designs of a rotary valve and Fig. 4 a design of a sealing arrangement of a rotary valve. DETAILED DESCRIPTION OF EMBODIMENTS

[0023] A perspective view of a rotary valve 1 can be seen in the Fig. 1 can be removed. On the upper side of the housing 2 of the cell lock 1, the inlet side 16 can be seen, to which a funnel-shaped feed for the bulk material is attached with several screws.

[0024] A side view of the rotary valve 1 according to Fig. 1 can the Fig. 2A The drive shaft 7 of the rotary valve 1 is guided along the symmetry axis of the essentially cylindrical housing 2. On each side, the housing 2 comprises a housing closure formed as a cover 11A, 11B. In the area of the (cylindrical) housing wall, a connection for a bypass of the pressure device is provided on the side, and in the area of the underside, in the area of the outlet side 17, which is arranged opposite the inlet side 16, a connection option (inlet 18) for the discharge pressure is provided. Adjacent to this is the outlet 19.

[0025] The Fig. 2B shows a view of the rotary valve from below, showing inlet 18 and outlet 19. The inlet 18 has a smaller diameter than the outlet 19, causing the gas from the pressure device (20) connected to the inlet 18 to expand in the cell 9. The larger outlet 19 also facilitates the emptying of the cell 9.

[0026] Fig. 3A shows a schematic sectional view of a variant of a rotary valve 1, similar to the rotary valve 1 according to the Figuren 1 bis 2B Between covers 11A and 11B, a sleeve 28 is provided, to which—at least in sections—a sealing means 13 is adjacent. The sealing means 13 is arranged in a sealing means chamber, and pressing means are provided which press the sealing means against the sleeve and the cellular wheel.

[0027] Fig. 3B shows a schematic sectional view of a variant of a rotary valve 1. The rotary valve 1 comprises a housing 2 in which a rotary valve 3 is arranged. The housing 2 is essentially cylindrical. The drive shaft 7 runs along the axis of symmetry 4 of the almost cylindrical housing 2 and through the central opening 5 of the rotary valve 3, to which the rotary valve 3 is rotatably mounted by means of a shaft holder 6. The rotary valve 3 comprises several rotary valve walls 8, which delimit the cells 9 of the rotary valve 1. The rotary valve 3 is in contact with the sleeve 28.

[0028] The drive shaft 7 is mounted at its ends in shaft bearings 10A, 10B. A cover 11A, 11B is arranged in the area of the bearings 10A, 10B, which defines the front end of the cellular wheel chamber 12. A sealing means 13 is provided between the cellular wheel 3 and the cover 11A, 11B, with which the cover 11A, 11B is sealed. The sealing means 13 is arranged in a groove-shaped sealing means chamber 14. The annular sealing means groove 14 comprises a first contact surface 15 for the sealing means 13. A second contact surface 15 for the sealing means 13 is arranged on the inside of the cover 11A, 11B.

[0029] The Fig. 3B Bulk material (not shown) enters the cell 9 on the inlet side 16 of the lock 1 from above, for example from a silo-like container to which the rotary valve 1 is connected. The outlet side 17 of the lock 1 is located below. On the outlet side 17 there is an inlet 18 for a conveying gas (air), which is blown into the (lower) cell 9 of the rotary valve 1 under a conveying pressure and which leaves the (lower) cell 9 in the area opposite the inlet 18 through an outlet 19. The bulk material is blown out of the (lower) cell 9 of the lock 1 through the outlet 19.

[0030] The discharge pressure in the lower cell 9 creates a pressure gradient within the lock 1: In the upper cell 9 (inlet side 16), there is no overpressure, while in the lower cell 9 (outlet side 17), there is an internal overpressure caused by the discharge pressure, compared to the pressure on the inlet side 16. This pressure difference causes mechanical stress on the drive shaft 7, which in turn causes a bending moment. The bending moment of the drive shaft 7 can lead to wear on the shaft bearings 10A, 10B and to wear on the shaft 7, even leading to shaft breakage.

[0031] To reduce the bending moment of the drive shaft 7, a static counterpressure is generated in the lock 1 by means of a pressure device 20, whereby pressure equalization occurs in the lock 1 - at least in some areas. The static counterpressure acts in the cavity 21, which borders two partial areas 22 of the drive shaft 7, which in turn border the cover 11A, 11B. The cavity 21 is essentially formed as left and right cylindrical recesses in the cellular wheel body and, when installed, forms two annular spaces 23, which are delimited by the shaft 7 and by the cover 11A, 11B, each in sections. Fig. 3B The cavity 21 shown can also be formed as a bore or several bores in the cellular wheel 3 (not shown in Fig. 3B ).

[0032] The static overpressure in the cavity 21 is built up by a pressure generator 26 connected to the pressure device 20, which is fluidically connected to the channel 24, which in turn is connected to the cavity 21. The pressure device 20 comprises a channel 24, which according to Fig. 3B consists of two sub-channels 25, each of which is fluidically connected to the pressure generator. The pressure generator 26 can be a pump or a compressor or can include these (not shown in Fig. 3B ). The pressure device 20 can comprise pressure reducers and / or valves and / or shut-off devices. The pressure generator 26 generates a total pressure for the lock device 1. The total pressure provided by the pressure generator 26 can be adjustable, controllable, and / or regulatable. The cavity overpressure and the discharge pressure form the total pressure or a partial pressure that is lower than the total pressure. Preferably, the cavity overpressure is greater than the discharge pressure.

[0033] Fig. 3B further shows that the sealant chamber 14 is fluidically connected to a channel 27, wherein the channel is fluidically connected to the pressure generation 26. With a pressure device 20 which comprises the channel 27, a sealant overpressure can be generated in the sealant chamber 14, whereby the sealant 13 is pressed more firmly against the contact surface 15. The contact pressure of the sealant 13 against the contact surface 15 is increased by the sealant overpressure in the sealant chamber 14. A separate pressure device can be provided for the sealant overpressure. It is expedient if both the sealant overpressure and the cavity overpressure are generated by a common pressure device 20. The pressure generation 26 is connected to the pressure device 20 or to the pressure devices or comprises them.

[0034] Not shown in Fig. 3B are control and / or regulating means with which the (partial) pressures of cavity overpressure, sealant overpressure, and delivery pressure can be controlled or regulated. The control / regulating means can include valves and pressure reducers, as well as logic with which the total pressure provided by the pressure generator 26 can be adjusted, as well as the respective partial pressures in the rotary valve 1. Control elements can be provided with which the control / regulation can be operated. For example, it can be provided that an absolute (cavity overpressure, sealant overpressure, and / or delivery) pressure is set using the control elements. It can also be provided that a relative pressure setting is selected (the "cavity overpressure" component, the "sealant overpressure" component, and the "delivery pressure" component together constitute 100% of the, preferably absolutely adjustable, total pressure).

[0035] A design of the sealant can be Figur 4 According to Fig. 4 A connection for a bypass of the pressure device (20) is provided, so that the sealing agent 13 is pressed against the sealing agent contact surfaces 15 by a gas pressure that can be adjusted and / or regulated if necessary. The sealing agent comprises a main seal with an inclined surface and two additional seals, approximately O-ring-like. The contact surface is located on the sleeve 28 and on the cellular wheel 3. The first additional seal is arranged on the sleeve 28, and the second additional seal is arranged in the sealing agent chamber in the area of the cover 11B. LIST OF REFERENCE SYMBOLS

[0036] 1 Rotary valve 2 Housing 3 Rotary valve 4 Axis of symmetry 5 Central opening 6 Shaft mount 7 Drive shaft 8 Rotary valve wall 9 Cell 10A, 10B Shaft bearing 11A, 11B Cover 12 Rotary valve chamber 13 Sealant 14 Sealant chamber, groove 15 Contact surface 16 Inlet side 17 Outlet side 18 Inlet 19 Outlet 20 Pressure device 21 Cavity 22 Partial area 23 Annular space 24 Channel 25 Partial channel 26 Pressure generation 27 Channel 28 Sleeve

Claims

1. A rotary feeder (1) for bulk goods, particularly for sprayed concrete, having a rotor chamber (12), a rotor (3) which is arranged in the rotor chamber (12) and which is connected to a drive shaft (7) in a rotationally fixed manner, and at least one cover (11A, 11B) which delimits the rotor chamber (12), wherein sealing means (13) that are arranged between the cover (11A, 11B) and rotor (3) are provided for connecting the cover (11A, 11B) to the rotor chamber (3) in a sealed manner, wherein a pressure device (20) is provided, using which the sealing means (13) and / or a sealing means chamber (14) comprising the sealing means (13) can be loaded with a sealing-means overpressure, wherein the sealing means (13) can be pressed more strongly onto at least one sealing-means contact surface (15) that is assigned to the sealing means (13) by means of the sealing-means overpressure, wherein the sealing means (13) is arranged in an annular sealing-means groove (14), and wherein the sealing-means groove (14) can be loaded with the sealing-means overpressure, characterized in that the sealing-means groove (14) is arranged in the cover (11A, 11B) and on a sleeve (28) which is arranged in the rotor chamber (12), is in sealing contact with the rotor (3) and adjoins the cover (11A, 11B), wherein the sealing-means contact surface (15) is located on the sleeve (28) and on the rotor (3), and wherein the sealing means (13) comprises a main seal and two auxiliary seals, wherein the first auxiliary seal is arranged on the sleeve (28) and the second auxiliary seal is arranged in the sealing-means space (14) in the region of the cover (11B).

2. The rotary feeder (1) according to Claim 1, characterized in that the sealing means (13) comprises a pressure surface, onto which a force can be exerted by the sealing-means overpressure, which force amplifies a contact force of the sealing means (13).

3. The rotary feeder (1) according to Claim 1 or 2, characterized in that using the pressure device (20) or using a second pressure device, at least one cavity (21) which is arranged in or on the rotor (3) and is inaccessible for the bulk goods can be loaded with a cavity overpressure.

4. The rotary feeder (1) according to Claim 3, characterized in that the cavity (21) is formed as at least one recess that is arranged on the rotor (3).

5. The rotary feeder (1) according to Claim 3 or 4, wherein the rotor (3) comprises a shaft retainer (6) which is formed as a central opening (5) running in the longitudinal direction, in which shaft retainer the drive shaft (7) is arranged, characterized in that the cavity (21) adjoins the central opening (5) at least in sections.

6. The rotary feeder (1) according to at least one of Claims 3 to 5, characterized in that the at least one cover (11A, 11B) delimits the cavity (21) at least in sections.

7. The rotary feeder (1) according to any one of Claims 3 to 6, characterized in that the cavity (21) forms at least one annular space (23) which adjoins the drive shaft (7) fully along at least one section of the drive shaft (7).

8. The rotary feeder (1) according to any one of Claims 1 to 7, characterized in that the pressure device (20) or the second pressure device generates a delivery pressure, wherein a cell (9) of the rotary feeder (1) can be loaded with the delivery pressure, and wherein the delivery pressure conveys the bulk goods out of the rotary feeder (1).

9. The rotary feeder (1) according to Claim 8, characterized in that the cavity overpressure and / or the sealing-means overpressure corresponds or almost corresponds to the delivery pressure or in that the cavity overpressure and / or the sealing-means overpressure is higher than the delivery pressure inside the rotor chamber (12).

10. The rotary feeder (1) according to any one of Claims 1 to 9, characterized by at least one channel (24, 27) which is fluidically connected to the pressure device (20) or to the second pressure device and using which the cavity (21) and / or the sealing-means groove (14) can be loaded with an overpressure.

11. The rotary feeder (1) according to any one of Claims 1 to 10, characterized in that the cavity overpressure and / or the sealing-means overpressure and / or the delivery pressure are controllable in an open- and / or closed-loop manner, particularly controllable in an open- and closed-loop manner.