Conveying device and mechanical face seal assembly with conveying device of this type

Abstract

The invention relates to a conveying device for conveying a liquid, comprising a rotatable part (61) and a stationary part (62), wherein there is a conveying gap (63) between the rotatable part (61) and the stationary part (62), and wherein a Tesla-valve-like conveying channel (63) is formed on the rotatable part (61) and / or on the stationary part (62), the conveying channel (63) having a greater flow resistance in one through-flow direction than in the other through-flow direction.

Description

[0001] Conveying device and mechanical seal arrangement with such a conveying device

[0002] Description

[0003] The invention relates to a conveying device, in particular a mechanical seal, for conveying a liquid in an axial direction and to a mechanical seal arrangement with a mechanical seal and a conveying device according to the invention.

[0004] Conveying devices in conjunction with mechanical seals are known, for example, as conveying threads for conveying a coolant and / or a barrier fluid toward the seal rings and the sealing gap. Such a conveying thread is known, for example, from DE 10 2011 118477 A1. This document discloses a floating conveying thread to prevent contact between the conveying thread and the surrounding housing sides during operation. A disadvantage of all previously known conveying threads is that if the direction of rotation on the shaft is reversed, the conveying direction in the conveying thread is also reversed. As a result, when using such conveying threads, it cannot always be guaranteed that sufficient coolant or barrier fluid is conveyed to the desired locations.

[0005] The object of the present invention is to provide a conveying device for conveying a liquid that enables the reliable conveyance of large volumes while being simple in design and easy and cost-effective to manufacture. Furthermore, the object of the invention is to provide a mechanical seal assembly with a conveying device that conveys sufficient volumes of liquid in all operating conditions.

[0006] This object is achieved by a conveying device having the features of claim 1 and a mechanical seal arrangement having the features of claim 10. The subclaims show preferred developments of the invention.

[0007] The conveying device according to the invention for conveying a liquid with the features of claim 1 has the advantage that it is possible to convey even larger quantities of liquid, such as cooling liquid or barrier fluid, in particular to a mechanical seal. The conveying device can also be used to convey lubricant or other liquids. The conveying device according to the invention comprises a rotatable part and a stationary part. Between the rotatable part and the stationary part there is a conveying gap through which the liquid to be conveyed is conveyed. Furthermore, a Tesla valve-like conveying channel is provided at least on the rotatable part or the stationary part. The Tesla valve-like conveying channel has a structure similar to a Tesla valve, which is a type of check valve without moving mechanical components.The Tesla-valve-like conveying channel exhibits greater flow resistance in one conveying direction than in the opposite conveying direction. Thus, hydrodynamic effects create a backflow preventer in the opposite direction. The Tesla-vertical conveying channel is formed entirely in the rotating or stationary section, or a Tesla-vertical conveying channel is formed in both the rotating and stationary sections.

[0008] Preferably, the Tesla valve-like conveying channel has a plurality of alternately arranged constriction regions and expansion regions. The expansion regions are preferably leaf-like or flat expansions, or alternatively, a separate flow channel with a longer flow length than a main channel of the Tesla valve-like conveying channel.

[0009] The extension areas are preferably curved. The extension areas are arranged alternately to the left and right of a conveying channel axis along a flow direction.

[0010] The conveying channel is preferably arranged at an acute angle a to the axial direction. The acute angle a is preferably in a range of 60° to 89°, preferably 70° to 80°, to the axial direction XX of the conveying device. The conveying rate can be influenced by selecting the angle a.

[0011] Particularly preferably, the conveying device comprises a plurality of Tesla-valve-like conveying channels arranged parallel to one another. This also ensures that the fluid is transferred from a first conveying channel to an adjacent second channel during conveying in the axial direction XX. The Tesla-like conveying channels are preferably each formed entirely within the lateral surfaces of the rotating and / or stationary part.

[0012] A particularly simple design is possible if the rotatable part is a ring on whose outer circumference the conveying channel is arranged, or if the stationary part is a ring on whose inner circumference the conveying channel is arranged. If the conveying channel is arranged on the outer circumference, the rotatable part can, for example, be easily fastened to a shaft or the like. If the conveying channel is arranged on an inner circumference, the part of the conveying device can be fixed to a housing or the like. Preferably, the ring and the shaft are a one-piece component, so that the ring is integrated into the shaft.

[0013] According to a particularly preferred embodiment of the invention, at least one first Tesla valve-like conveying channel is arranged on the rotating part, and at least one second Tesla valve-like conveying channel is arranged on the stationary part. This enables conveying independent of the direction of rotation.

[0014] Preferably, all conveying channels on the rotating part and / or the stationary part are geometrically identical.

[0015] Particularly preferably, the first and second Tesla valve-like conveying channels are arranged at an acute angle to the axial direction, with the first and second conveying channels being oriented in the same direction. This makes it possible for the conveying direction of the conveying device to remain the same even if the direction of rotation of the rotatable part is reversed. In other words, the conveying device conveys in a first direction when rotating in a first direction, and when reversing the conveying device in a direction opposite to the first direction, the conveying device still conveys in the first direction. This can be used advantageously, in particular, with mechanical seals, which must seal rotating components whose direction of rotation changes during operation.This means that the conveying device for such a mechanical seal can convey cooling fluid and / or barrier fluid to the mechanical seal safely and in the required large quantities, regardless of the direction of rotation of the rotating component.

[0016] Furthermore, the present invention relates to a mechanical seal assembly comprising a rotating and a stationary seal ring, which define a sealing gap between their sliding surfaces. The mechanical seal assembly comprises a conveying device as described above.

[0017] The mechanical seal assembly preferably further comprises a barrier fluid device, wherein the conveying device according to the invention conveys the barrier fluid to the sealing gap of the mechanical seal. The mechanical seal assembly further preferably comprises a cooling device, wherein the conveying device according to the invention conveys a cooling fluid to the mechanical seal.

[0018] The conveying device according to the invention can also be used, in particular, as a lubricant pump, for example, for supplying lubricant to bearings or other rotating components. Preferred embodiments of the invention are described in detail below with reference to the accompanying drawing. In the drawing:

[0019] Fig. 1 is a schematic sectional view of a mechanical seal arrangement with a conveying device according to a first embodiment of the invention,

[0020] Fig. 2 is a schematic plan view of a rotatable part of the conveyor device of Fig. 1,

[0021] Fig. 3 is a schematic sectional view of a stationary part of the conveyor device of Fig. 1,

[0022] Fig. 4 is a schematic representation of a development of a Tesla valve-like

[0023] Conveying channel of the conveying device of Fig. 1 ,

[0024] Fig. 5 is a schematic sectional view of the mechanical seal arrangement with

[0025] Conveyor device of Fig. 1 with reverse direction of rotation and

[0026] Fig. 6 is a schematic sectional view of a mechanical seal arrangement with a conveying device according to a second embodiment of the invention.

[0027] In the following, with reference to Figures 1 to 5, a mechanical seal arrangement

[0028] 1 according to a first preferred embodiment of the invention is described in detail.

[0029] As can be seen from Fig. 1, the mechanical seal arrangement 1 comprises a mechanical seal

[0030] 2 with a rotating seal ring 3 and a stationary seal ring 4. A sealing gap 5 is defined between the sliding surfaces of the rotating seal ring 3 and the stationary seal ring 4.

[0031] The mechanical seal arrangement 1 seals a product area 11 on a shaft 9 from an area 12 to be sealed.

[0032] The rotating seal ring 3 is connected to the shaft 9 via a sleeve 10. The stationary seal ring 4 is fixed to a housing 8.

[0033] The mechanical seal assembly 1 further comprises a conveying device 6 configured to convey a fluid. As can be seen from Fig. 1, the conveying device 6 comprises a rotatable part 61 and a stationary part 62. The rotatable part 61 is arranged directly on the shaft 9. The stationary part 62 is arranged on the housing 8.

[0034] A conveying gap 60 is arranged between the rotatable part 61 and the stationary part 62. The conveying device 6 conveys in the axial direction XX of the mechanical seal arrangement, which is shown in Fig. 1 in the flow direction 7 of the liquid flow.

[0035] The rotating part 61 and the stationary part 62 each have one or more conveying channels 63. The conveying channels are designed as Tesla valve-like conveying channels. Each of the conveying channels is completely formed in the rotating and stationary parts.

[0036] Fig. 2 shows in detail the rotatable part 61 of the conveyor device 6. As can be seen from Fig. 2, a plurality of parallel conveyor channels 63 are arranged on the rotatable part 61. The conveyor channels 63 are arranged at an acute angle a to the axial direction XX (see Fig. 2).

[0037] Fig. 3 shows a schematic sectional view of the stationary part 62 of the conveyor device 6. As can be seen from Fig. 3, the stationary part 62 has a plurality of conveyor channels 63 on its inner circumference, which are also arranged at the same angle a to the axial direction XX on the inner circumference. Here, a plurality of conveyor channels 63 are also arranged parallel to one another.

[0038] As a comparison between Figures 2 and 3 immediately shows, the conveying channels of the rotating part 61 and the stationary part 62 are aligned in the same direction. Thus, the conveying channels 63 of the rotating part 61 and the stationary part 62 run parallel to each other.

[0039] Fig. 4 shows a schematic development of a conveyor channel 63. The conveyor channels are designed the same in the rotatable part 61 as in the stationary part 62.

[0040] As can be seen from Fig. 4, each conveying channel 63 has constriction regions 64 and expansion regions 65. Each conveying channel 63 has a plurality of alternating constriction regions 64 and expansion regions 65. The expansion regions 65 are flat, arc-shaped regions arranged in a sheet-like manner along a main direction, alternating left and right along a conveying channel axis YY. A constriction region 64 is provided between each two expansion regions 65. This configuration results in greater flow resistance in one direction of the conveying channel 63 than in the other direction of the flow channel.

[0041] To ensure that conveying is possible in the same axial direction regardless of the direction of rotation, the Tesla valve-like conveying channel 63 on the stationary part 62 of the conveying device 6 is arranged in the same direction as on the rotatable part and at the same angle. This makes it possible for the conveying device 6, as shown in Fig. 1, to convey a liquid in a first direction of rotation A by means of the conveying channels 63 in the rotatable part 61 in the flow direction 7 through the conveying gap 60, whereby the conveying channels in the stationary part block a fluid passage through it due to a hydrodynamic effect. As shown in Fig. 5, with an opposite direction of rotation B, the conveying channels 63 of the rotatable part 61 block, whereas liquid is conveyed in the conveying channels 63 of the stationary part 62, so that conveying is carried out in the same direction (flow direction 7) through the conveying gap 60 by means of the conveying channels 63 in the stationary part 62.Since the angle and geometric shape of the conveying channels 63 in the rotating and stationary part are the same, the conveyed amount of liquid is also the same.

[0042] Thus, a conveying capacity of the conveying device can always be achieved in the same direction through the conveying gap 60, regardless of the direction of rotation. It should be noted that, preferably by varying the angle α on the rotatable and stationary parts, different conveying quantities can also be conveyed depending on the direction of rotation. Thus, the invention can provide a conveying device 6 capable of conveying the same or a different amount of liquid in the same direction, regardless of the direction of rotation of a rotatable part 61.

[0043] Since in the first embodiment a width B1 of the rotatable part 61 and a width B2 of the stationary part 62 of the conveying device 6 are the same and the angles a are also the same, the conveyed quantity of liquid in the flow direction 7 is also the same regardless of a direction of rotation (A or B).

[0044] Fig. 6 shows a mechanical seal arrangement 1 according to a second embodiment of the invention. Identical or functionally identical parts are designated by the same reference numerals as in the first embodiment. As can be seen from Fig. 6, the conveying device 6 of the second embodiment has a rotatable part 61 which, as in the first embodiment, has conveying channels 63 with constriction regions 64 and expansion regions 65. The rotatable part 61 is arranged directly on the shaft 9. The stationary part 62 of the conveying device 6 is formed in the second embodiment by a peripheral wall 80 of the housing 8. Thus, the conveying device 6 of the second embodiment has a significantly simplified structure and comprises conveying channels 63 in the manner of a Tesla valve only on the rotatable part 61.If the conveying channels 63 of the rotatable part 61 are arranged at an acute angle to the axial direction XX, as in the first embodiment, large quantities are conveyed in the direction of flow 7, and when the direction of rotation is reversed, the conveyed quantity is significantly reduced and tends towards zero. The second embodiment is intended in particular for applications in which a reversal of the direction of rotation of the shaft 9 to be sealed does not occur. This allows the construction of the conveying device 6 to be simpler and more cost-effective. Otherwise, this embodiment corresponds to the first embodiment, so that reference can be made to the description given there.

[0045] In addition to the above written description of the invention, reference is hereby explicitly made to the graphic representation of the invention in Figs. 1 to 6 for its supplementary disclosure.

[0046] List of reference symbols

[0047] 1 mechanical seal arrangement

[0048] 2 mechanical seals

[0049] 3 rotating slide ring

[0050] 4 stationary sliding ring

[0051] 5 Sealing gap

[0052] 6 Conveyor system

[0053] 7 Flow direction through the conveying gap

[0054] 8 housings

[0055] 9 Wave

[0056] 10 sleeves

[0057] 11 Product area

[0058] 12 area to be sealed

[0059] 60 conveyor gap

[0060] 61 rotating part

[0061] 62 stationary part

[0062] 63 conveyor channel

[0063] 64 Constriction area

[0064] 65 Expansion area

[0065] 80 peripheral wall

[0066] A first direction of rotation

[0067] B second direction of rotation opposite to the first direction of rotation

[0068] B1 Width of the rotating part

[0069] B2 Width of the stationary part

[0070] XX Axial direction

[0071] YY conveyor channel axis a angle

Claims

Claims 1 . Conveying device for conveying a liquid, comprising - a rotatable part (61) and - a stationary part (62), - wherein a conveying gap (63) is present between the rotatable part (61) and the stationary part (62), and - wherein a Tesla valve-like conveying channel (63) is formed on the rotatable part (61) and / or on the stationary part (62), wherein the conveying channel (63) has a greater flow resistance in one flow direction than in the other flow direction.

2. Conveying device according to claim 1, wherein the conveying channel (63) has a plurality of alternately arranged narrowing regions (64) and widening regions (65).

3. Conveying device according to claim 2, wherein the extension regions (65) are arcuate and are arranged alternately along a flow direction through the conveying channel (63) on a conveying channel axis (YY).

4. Conveying device according to one of the preceding claims, wherein the conveying channel (63) is arranged at an acute angle (a) to the axial direction (XX).

5. Conveyor device according to claim 4, wherein the acute angle (a) is in a range of 60° to 89°.

6. Conveying device according to one of the preceding claims, comprising a plurality of conveying channels (63) arranged parallel to one another.

7. Conveying device according to one of the preceding claims, wherein the rotatable part (61) is a ring on the outer circumference of which the conveying channel 63 is arranged and / or wherein the stationary part (62) is a ring on the inner circumference of which the conveying channel (63) is arranged.

8. Conveying device according to one of the preceding claims, wherein all conveying channels (63) are geometrically identical.

9. Conveying device according to one of the preceding claims, wherein the conveying channel (63) of the rotatable part (61) and the conveying channel (63) of the stationary part (62) are arranged at the same angle (α).

10. Mechanical seal arrangement comprising - a mechanical seal (2) with a rotating seal ring (3) and a stationary seal ring (4), which define a sealing gap (5) between their sliding surfaces, and - a conveying device (6) according to one of the preceding claims.

Images