Scroll pump with two-piece crankshaft

Abstract

The invention discloses a scroll pump with a two-piece crankshaft. In a pump head for a scroll pump, an orbiting scroll is coupled to a crank of a crankshaft. When the crankshaft rotates, the crank drives the orbiting scroll to rotate relative to the one or more fixed scrolls to pump fluid from the inlet to the outlet. A stub shaft is attached to the crank and may be removed as at least partially detached part of the pump head. The adjusting nut can adjust the axial position of the movable scroll plate relative to the fixed scroll plate. The adjustment nut may be removed with the stub shaft and then reinstalled without changing the axial position of the adjustment nut relative to the stub shaft.

Description

Technical Field

[0001] The present invention relates to a scroll pump, and more particularly to the configuration of a crankshaft used in a scroll pump. Background Art

[0002] Scroll pumps are widely used as compressors for supplying pressurized working fluid (such as compressed air) and as vacuum pumps for evacuating a chamber by removing the working fluid from the chamber. As understood by those skilled in the art, a scroll pump has at least one pumping (or compression) stage formed by a moving scroll disk and a stationary (static) scroll disk. The moving scroll disk has moving scroll blades that extend axially from a radially oriented moving scroll plate (or base) towards the stationary scroll disk. The stationary scroll disk has stationary scroll blades that extend axially in the opposite direction from a radially oriented stationary scroll plate (or base) towards the moving scroll disk. The scroll blades (or "scrolls") are helical. That is, each scroll blade extends in a helical path around a central region of its corresponding scroll plate for multiple turns. The moving scroll blades and the stationary scroll blades are nested with each other. The scroll pump also has an electric motor-driven crankshaft that rotates about its central axis or drive axis. The crankshaft has an eccentrically positioned crank at an end opposite to the motor. The central axis of the crank is radially offset from the drive axis of the main part of the crankshaft. Thus, when the main part of the crankshaft rotates about the drive axis, the crank orbits in a circle (the radius of which corresponds to the radial offset distance) about the drive axis. The moving scroll disk is coupled to the crank and thus orbits with the crank, and the moving scroll disk itself does not rotate about its own axis.

[0003] During operation, the moving scroll disk is driven by the crankshaft to orbit about the drive axis relative to the stationary scroll disk to form one or more moving, variable-volume pumping chambers or regions, also referred to as "pockets", between the moving scroll blades and the stationary scroll blades. Each pocket is defined and bounded between adjacent segments of the moving scroll blades and the stationary scroll blades. As the orbiting motion of the moving scroll disk occurs, the pocket receives (usually gaseous) working fluid from the pump inlet and displaces (transports) the working fluid to the pump outlet. As the pocket moves according to the orbiting motion, the volume of the space inside the pocket decreases, thereby compressing the working fluid to some extent as the working fluid is displaced towards the pump outlet.

[0004] An example of the structure and operation of such a scroll pump is described in U.S. Patent No. 5,855,473, the entire contents of which are incorporated herein by reference.

[0005] A scroll pump may have more than one pumping stage, such as two pumping stages fluidly connected in series. For example, the orbiting scroll disk may be positioned between two stationary scroll disks, namely an outer stationary scroll disk having outer stationary scroll vanes and an inner stationary scroll disk having inner stationary scroll vanes. In this case, the orbiting scroll disk has one orbiting scroll vane on its inner portion and another orbiting scroll vane on its outer portion. The outer orbiting scroll vane nests with the outer stationary scroll vanes to jointly define one (outer) pumping stage, and the inner orbiting scroll vane nests with the inner stationary scroll vanes to jointly define another (inner) pumping stage. In operation, the first pumping stage (depending on the configured outer or inner stage) receives the working fluid from the pump inlet, compresses the working fluid, and conveys the compressed working fluid to the second pumping stage. The second pumping stage further compresses the working fluid and discharges the further compressed working fluid toward the pump outlet. An example of such a two-stage scroll pump is described in U.S. Patent No. 5,855,473 mentioned above.

[0006] In a single-stage or multi-stage scroll pump, the orbiting scroll disk and the stationary scroll disk do not contact each other. Instead, there is a small axial clearance between the blade tip (free end) of each scroll vane and the surface of the scroll plate that is axially adjacent to and faces the corresponding blade tip. For example, on a given (outer or inner) side of the orbiting scroll plate, the blade tip of the orbiting scroll vane is spaced from the surface of the stationary scroll plate by an axial clearance. Similarly, on the same side, the blade tip of the stationary scroll vane is spaced from the surface of the orbiting scroll plate by an axial clearance. The axial clearance is necessary so that the orbiting scroll disk can move relative to the stationary scroll disk. The scroll pump may be a "dry" scroll pump, which means it is not sealed or lubricated by a liquid (such as oil, etc.). In this case, the axial clearance is closed and sealed by tip seals mounted on the respective blade tips, such that each tip seal extends continuously along the same helical path as its corresponding scroll vane. The tip seals enhance the sealing interface between the orbiting scroll disk and the stationary scroll disk without impairing the movement of the orbiting scroll disk. The tip seals wear over time with the operation of the pump and thus eventually need to be replaced with new ones.

[0007] The size (axial dimension) of the axial clearance is determined by the axial position of the orbiting scroll disk relative to the stationary scroll disk. In many cases, it is very important to control the axial relationship between the orbiting scroll disk and the stationary scroll disk. For this purpose, various axial adjustment measures have been used. As an example (see FIGS. 2 and Figure 3) The axial position of the orbiting scroll can be controlled (adjusted) by an adjusting nut that is threadedly connected to the crank of the crankshaft. Rotation of the adjusting nut adjusts its axial position along the length of the crank (translating the adjusting nut). The adjusting nut interfaces with the orbiting scroll such that the adjusting nut can be used to adjust (set) the axial position of the orbiting scroll relative to the fixed scroll and thereby adjust the size of the axial clearance. Once the correct axial position has been established, the adjusting nut is fastened in place by tightening four locking screws.

[0008] As described above, the tip seals on the scroll vanes need to be replaced regularly. To access the tip seals, the pump head needs to be partially disassembled and reassembled after installing new tip seals. For a scroll pump having an inner pumping stage, the disassembly includes removing the orbiting scroll to gain access to the inner portion of the orbiting scroll and the inner fixed scroll. Unfortunately, it may be necessary to remove the adjusting nut to remove the orbiting scroll and access all of the tip seals. Once the adjusting nut has been removed and then reinstalled onto the crank, careful measurements (e.g., using a depth gauge) must be taken to accurately reposition the adjusting nut in the correct axial position to re-establish the correct setting of the axial position of the orbiting scroll relative to the fixed scroll. This task takes a significant amount of time and is prone to errors (e.g., inaccuracies, imprecisions, etc.), especially when the personnel performing the maintenance are not highly trained. Such errors rarely occur in a factory that manufactures scroll pumps because the factory has special jigs and fixtures and personnel who are experienced and well-trained in correctly and precisely setting the adjusting nut during the initial assembly of the scroll pump.

[0009] In view of the above, a further solution regarding scroll pump maintenance is needed. Summary of the Invention

[0010] To address the above problems in whole or in part and / or other problems that have been observed by those skilled in the art, the present disclosure provides methods, processes, systems, devices, instruments, and / or apparatuses as described by way of example in the following embodiments.

[0011] According to one embodiment, a scroll pump (e.g., a scroll pump assembly, or at least its scroll pump head) includes: a pumping stage that includes an orbiting scroll and a fixed scroll nested together, wherein the orbiting scroll is configured to orbit about a drive axis relative to the fixed scroll to form a moving pocket between the orbiting scroll and the fixed scroll that effectively pumps fluid from a pump inlet to a pump outlet; a crankshaft that includes a main shaft that is capable of rotating about the drive axis and a crank that is radially offset from the drive axis and coupled to the orbiting scroll, wherein the crank is configured to drive the orbiting scroll to orbit about the drive axis in response to rotation of the main shaft; and a stub shaft that is removably attached to the crank.

[0012] According to another embodiment, a method for servicing a scroll pump (e.g., a scroll pump assembly or at least its scroll pump head) includes: providing a scroll pump according to any of the embodiments described herein; removing a short shaft from a crank; and removing an orbiting scroll from the crank.

[0013] According to another embodiment, a method for servicing a scroll pump (e.g., a scroll pump assembly or at least its scroll pump head) includes: providing a scroll pump head that includes: a pumping stage that includes an orbiting scroll and a stationary scroll nested together, wherein the orbiting scroll is configured to orbit about a drive axis relative to the stationary scroll to form a moving pocket therebetween that effectively pumps fluid from a pump inlet to a pump outlet; a crankshaft that includes a main shaft that is rotatable about the drive axis and a crank that is radially offset from the drive axis and coupled to the orbiting scroll, wherein the crank is configured to drive the orbiting scroll to orbit about the drive axis in response to rotation of the main shaft; and a short shaft that is removably attached to the crank. The method further includes: removing the short shaft from the crank; and removing the orbiting scroll from the crank.

[0014] Other embodiments of the scroll pump and / or the method will now be summarized.

[0015] In an embodiment, the orbiting scroll includes an orbiting scroll bore, and the short shaft is disposed in the orbiting scroll bore when removably attached to the crank.

[0016] In an embodiment, the scroll pump includes a short shaft fastener configured to removably attach the short shaft to the crank. The short shaft fastener may be separate from or integral with the short shaft. In one embodiment, the crank includes a crank axial bore having an internal thread, and the short shaft fastener includes a short shaft screw having an external thread configured to engage the internal thread. The short shaft screw may be separate from or integral with the short shaft.

[0017] In one embodiment, the crank includes a crank end adjacent to the short shaft and a buffer portion disposed at the crank end, the buffer portion having an outer diameter that is reduced compared to the remainder of the crank. In one embodiment, the scroll pump includes an annular member (e.g., a bearing, a gasket, etc.) that surrounds the crank such that a radial clearance is defined between the crank and the annular member, wherein the radial clearance includes an enlarged radial clearance section defined between the buffer portion and the annular member, and the enlarged radial clearance section is greater than the remainder of the radial clearance.

[0018] In an embodiment: The orbiting scroll has an outer portion and an inner portion, and along an axial direction relative to the drive axis, the outer portion is closer to the environment outside the scroll pump head than the inner portion; the fixed scroll is an inner fixed scroll, the pumping stage is an inner pumping stage, the inner pumping stage includes the inner fixed scroll and the inner portion of the orbiting scroll, and the orbiting scroll and the inner fixed scroll are nested together at the inner portion; and the outer portion prevents access to the inner portion and the inner fixed scroll in a direction from the outer portion toward the inner portion.

[0019] In an embodiment, the orbiting scroll includes an inner orbiting tip seal, the inner fixed scroll includes an inner fixed tip seal, and the outer portion prevents access to the inner orbiting tip seal and the inner fixed tip seal in a direction from the outer portion toward the inner portion.

[0020] In an embodiment, the scroll pump includes an outer pumping stage, the outer pumping stage includes an outer fixed scroll and the outer portion of the orbiting scroll, wherein: the orbiting scroll and the outer fixed scroll are nested together at the outer portion; and the orbiting scroll is configured to orbit about the drive axis relative to the outer fixed scroll to form a moving pocket at the outer portion between the orbiting scroll and the outer fixed scroll.

[0021] In an embodiment: The orbiting scroll includes an inner orbiting tip seal and an outer orbiting tip seal, the inner fixed scroll includes an inner fixed tip seal, and the outer fixed scroll includes an outer fixed tip seal; and the outer portion prevents access to the inner orbiting tip seal and the inner fixed tip seal in a direction from the outer portion toward the inner portion.

[0022] In an embodiment: The orbiting scroll has an outer portion and an inner portion, and along an axial direction relative to the drive axis, the outer portion is closer to the environment outside the scroll pump head than the inner portion; the fixed scroll is an inner fixed scroll, and the pumping stage is an inner pumping stage, the inner pumping stage includes the inner fixed scroll and the inner portion of the orbiting scroll; the orbiting scroll includes an orbiting scroll plate oriented in a transverse plane orthogonal to the drive axis and inner orbiting scroll vanes; the inner fixed scroll includes an inner fixed scroll plate oriented in the transverse plane and inner fixed scroll vanes; the inner orbiting scroll vanes extend axially from the orbiting scroll plate toward the inner fixed scroll plate; the inner fixed scroll vanes extend axially from the inner fixed scroll plate toward the orbiting scroll plate and are nested with the inner orbiting scroll vanes; and the inner orbiting scroll vanes and the inner fixed scroll vanes are disposed at the inner portion such that the outer portion prevents access to the inner orbiting scroll vanes and the inner fixed scroll vanes.

[0023] In an embodiment, the orbiting scroll includes an orbiting tip seal mounted to the inner orbiting scroll blade at an axial gap between the inner orbiting scroll blade and the inner stationary scroll plate, the inner stationary scroll includes a stationary tip seal mounted to the inner stationary scroll blade at an axial gap between the inner stationary scroll blade and the orbiting scroll plate, and the outer portion prevents access to the orbiting tip seal and the stationary tip seal.

[0024] In an embodiment, the scroll pump head further includes an outer pumping stage, the outer pumping stage including an outer stationary scroll and an outer portion of the orbiting scroll, wherein: the orbiting scroll is configured to orbit relative to the outer stationary scroll about a drive axis in addition to the inner stationary scroll to form a moving pocket between the orbiting scroll and the outer stationary scroll; the orbiting scroll includes outer orbiting scroll blades; the outer stationary scroll includes an outer stationary scroll plate oriented in a transverse plane and outer stationary scroll blades; the outer orbiting scroll blades extend axially from the orbiting scroll plate toward the outer stationary scroll plate; the outer stationary scroll blades extend axially from the outer stationary scroll plate toward the orbiting scroll plate and are nested with the outer orbiting scroll blades; and the outer orbiting scroll blades and the outer stationary scroll blades are disposed on the outer portion.

[0025] In an embodiment: the orbiting scroll includes an inner orbiting tip seal mounted to the inner orbiting scroll blade at an axial gap between the inner orbiting scroll blade and the inner stationary scroll plate, and an outer orbiting tip seal mounted to the outer orbiting scroll blade at an axial gap between the outer orbiting scroll blade and the outer stationary scroll plate; the inner stationary scroll includes an inner stationary tip seal mounted to the inner stationary scroll blade at an axial gap between the inner stationary scroll blade and the orbiting scroll plate; the outer stationary scroll includes an outer stationary tip seal mounted to the outer stationary scroll blade at an axial gap between the outer stationary scroll blade and the orbiting scroll plate; and the outer portion prevents access to the inner orbiting tip seal and the inner stationary tip seal.

[0026] In an embodiment, the scroll pump includes an adjusting nut axially adjustable relative to the short axis, wherein the adjusting nut is configured to contact a surface coupled to or integral with the orbiting scroll, and axial adjustment of the adjusting nut adjusts the axial position of the orbiting scroll relative to the stationary scroll.

[0027] In an embodiment, the adjusting nut engages the short axis at a preset axial position on the short axis, and the adjusting nut and the short axis can be removed from and reinstalled onto the crank as a unit without changing the preset axial position.

[0028] In an embodiment, the adjusting nut includes adjusting nut threads, and the short axis includes short axis threads configured to engage the adjusting nut threads.

[0029] In an embodiment, the adjusting nut is located in a position that prevents removal of the orbiting scroll from the crank.

[0030] In an embodiment, removing the orbiting scroll disk includes removing the entire orbiting scroll disk as a single-piece component.

[0031] In an embodiment, the short shaft is removably attached to the crank via a fastener, and removing the short shaft includes operating the fastener to loosen the short shaft from the crank. In one embodiment, removing the short shaft includes unscrewing the short shaft from the crank.

[0032] In an embodiment: prior to removing the orbiting scroll disk, the orbiting scroll disk prevents access to the inner components of the scroll pump head; and the method further includes servicing or replacing the inner components after removing the orbiting scroll disk. In one embodiment, the inner components are at least one of the orbiting scroll vanes of the orbiting scroll disk or the fixed scroll vanes of the fixed scroll disk.

[0033] In an embodiment: the orbiting scroll disk includes an orbiting tip seal, and the fixed scroll disk includes a fixed tip seal; prior to removing the orbiting scroll disk, the orbiting scroll disk prevents access to the orbiting tip seal and the fixed tip seal; and the method further includes replacing at least one of the orbiting tip seal or the fixed tip seal with a new tip seal after removing the orbiting scroll disk.

[0034] In an embodiment: the orbiting scroll disk has an outer portion and an inner portion, and along an axial direction relative to the drive axis, the outer portion is closer to the environment outside the scroll pump head than the inner portion; the fixed scroll disk is an inner fixed scroll disk, the pumping stage is an inner pumping stage, the inner pumping stage includes the inner fixed scroll disk and the inner portion of the orbiting scroll disk, and the orbiting scroll disk and the outer fixed scroll disk are nested together on the inner portion; and prior to removing the orbiting scroll disk, the outer portion prevents access to the inner portion and the inner fixed scroll disk in a direction from the outer portion toward the inner portion.

[0035] In an embodiment: the orbiting scroll disk includes an orbiting tip seal; the inner fixed scroll disk includes a fixed tip seal; prior to removing the orbiting scroll disk, the outer portion prevents access to the orbiting tip seal and the fixed tip seal in a direction from the outer portion toward the inner portion; and the method further includes replacing at least one of the orbiting tip seal or the fixed tip seal with a new tip seal after removing the orbiting scroll disk.

[0036] In an embodiment: the scroll pump head includes an outer pumping stage, the outer pumping stage includes an outer fixed scroll disk and the outer portion of the orbiting scroll disk; the orbiting scroll disk and the outer fixed scroll disk are nested together on the outer portion; and the orbiting scroll disk is configured to orbit about the drive axis relative to the outer fixed scroll disk to form a moving pocket on the outer portion between the orbiting scroll disk and the outer fixed scroll disk.

[0037] In an embodiment: the orbiting scroll includes an inner orbiting tip seal and an outer orbiting tip seal, the stationary scroll includes an inner stationary tip seal, and the outer stationary scroll includes an outer stationary tip seal; before removing the orbiting scroll, the outer portion prevents access to the inner orbiting tip seal and the inner stationary tip seal in a direction from the outer portion toward the inner portion; and the method further includes replacing at least one of the inner orbiting tip seal or the inner stationary tip seal with a new tip seal after removing the orbiting scroll.

[0038] In an embodiment, the method includes removing the outer stationary scroll before removing the orbiting scroll.

[0039] In an embodiment, the scroll pump head includes an adjusting nut that is axially adjustable relative to the short shaft, and before removing the short shaft, the adjusting nut is located at a preset axial position relative to the short shaft. In one embodiment, removing the short shaft includes removing the adjusting nut and the short shaft as an assembly without changing the preset axial position. In one embodiment, after removing the adjusting nut together with the short shaft, the method includes reinstalling the adjusting nut and the short shaft together by reattaching the short shaft to the crank, wherein the preset axial position of the adjusting nut on the short shaft determines the axial position of the orbiting scroll relative to the stationary scroll, and the reattachment restores the axial position of the orbiting scroll relative to the stationary scroll corresponding to the preset axial position.

[0040] Other devices, apparatuses, systems, methods, features, and advantages of the present invention will be or will become apparent to those skilled in the art by reviewing the following drawings and detailed description. All such additional systems, methods, features, and advantages are included within the scope of this specification, within the scope of the present invention, and are protected by the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention can be better understood by reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon illustrating the principles of the present invention. In the drawings, like reference numerals refer to corresponding parts throughout the different views.

[0042] Figure 1 is a cross-sectional front view of an example of a scroll pump (assembly) that can implement the subject matter disclosed herein.

[0043] Figure 2A is a cross-sectional front view of an example of the pump head of a scroll pump according to an embodiment of the present disclosure.

[0044] Figure 2B is Figure 2A a close-up view of the area of the pump head shown.

[0045] Figure 3 is associated with Figure 2AA perspective sectional view of the orbiting scroll plate included together with the pump head shown.

[0046] Figure 4 is Figure 2A A sectional plan view (in a transverse plane) of the pumping stage of the pump head shown.

[0047] Figure 5 is Figure 2A A close-up view of the area of two pumping stages of the pump head shown.

[0048] Figure 6 is an example of an adjusting nut that can be included together with the Figure 2A pump head shown. A perspective view.

[0049] Figure 7 is a sectional front view of an example of an area of a pump head similar to Figure 2B according to another embodiment of the present disclosure.

[0050] Figure 8A is a sectional front view of an example of an area of a pump head similar to Figure 2B according to another embodiment of the present disclosure.

[0051] Figure 8B is a perspective view of the crank end of a crankshaft included together with the Figure 8A pump head shown.

[0052] Unless otherwise specifically stated, all illustrations in the drawings are considered to be schematic. Detailed Description

[0053] In the present disclosure, all "embodiments", "aspects", "examples" and "examples" described are considered to be non-limiting and non-exclusive. Therefore, even if not explicitly described, the fact that a specific "embodiment", "aspect", "example" or "example" is explicitly described herein does not exclude other "embodiments", "aspects", "examples" and "examples" from the scope of the present disclosure. In the present disclosure, the terms "embodiment", "aspect", "example" and "example" can be used interchangeably, that is, they are considered to have interchangeable meanings.

[0054] In the present disclosure, unless otherwise specifically stated, when modifying a specified numerical value, the terms "substantially", "about" or "approximately" can be considered to include a value range of the numerical value + / - 10%.

[0055] Figure 1FIG. 0 is a cross-sectional front view of an example of a scroll pump (assembly) 100 that can implement the subject matter disclosed herein. As will be understood by those skilled in the art, the scroll pump 100 can be configured to operate as a vacuum pump or a compressor. The type of working fluid pumped by the scroll pump 100 depends on the application for which the scroll pump 100 is used. The working fluid is typically a gas (or gas mixture), such as, for example, air, oxygen, nitrogen, noble gases (such as helium, argon, etc.), gaseous compounds (such as carbon dioxide, refrigerant, etc.), gases used in chemical, processing, or analytical processes, etc. Alternatively, the working fluid can be a liquid. The structure and operation of scroll pumps are generally understood by those skilled in the art, and thus the scroll pump 100 and some of its components will only be briefly described herein to provide a background for the presently disclosed subject matter.

[0056] The scroll pump 100 includes a pump head 102 powered by an electric motor 104. Generally, as will be understood by those skilled in the art, the electric motor 104 is an electric motor that includes an electric motor rotor (not shown), and the electric motor rotor is driven to rotate relative to the electric motor stator (not shown) by a magnetic field established between a permanent magnet and / or an electromagnet provided together with the electric motor rotor and the electric motor stator. The electric motor rotor is coupled to an electric motor (output) shaft 108, and thus the electric motor shaft 108 rotates with the electric motor rotor. The electric motor shaft 108 is coupled to a crankshaft 112 through a suitable shaft coupling 116 such that the crankshaft 112 is driven to rotate by the electric motor rotor via the electric motor shaft 108 and the shaft coupling 116. As will be understood by those skilled in the art, the shaft coupling 116 can be a mechanical coupling (such as, for example, a shaft joint, a star coupling, etc.) or a non-contact coupling, such as an axially or radially oriented magnetic coupling. Alternatively, the pump head 102 and the electric motor 104 are directly coupled through a single drive shaft without using a separate electric motor shaft 108, crankshaft 112, and intermediate shaft coupling 116. At least a major portion of the electric motor shaft 108 and the crankshaft 112 rotate concentrically or coincidentally about a central drive axis D.

[0057] The pump head 102 includes a pump frame 120, which can be of a one-piece construction or a multi-piece construction. In a multi-piece construction, two or more separate frame parts can be assembled with each other and disassembled from each other. The pump frame 120 can be configured to serve as a pump housing that encloses various components of the pump head 102 and / or as a structural support to which various components are attached or integrally formed therewith. The pump head 102 also includes one or more pumping elements, which are configured to define one or more pumping (or compression) stages 124. At least one pumping element is coupled to and driven to move by a crankshaft 112. In the embodiments described herein, the pumping element is a scroll disk, as described in more detail below. The pump head 102 also includes a pump inlet 128 and an inlet conduit 132 (e.g., one or more channels, pipes, tubes, chambers, manifolds, plenum chambers, headers, etc.), which are configured to direct the inflowing (suction) working fluid (the fluid being pumped) stream from the pump inlet 128 to the pumping stage 124. The pump head 102 also includes a pump outlet 136 and an outlet conduit 140 (e.g., one or more channels, pipes, tubes, chambers, manifolds, plenum chambers, headers, etc.), which are configured to direct the outflowing (discharge) working fluid stream from the pumping stage 124 to the pump outlet 136. Thus, the pump head 102 (particularly the pumping stage 124) is configured to transport (or displace by a pumping action) the working fluid from the pump inlet 128 through the inlet conduit 132, the pumping stage 124, and the outlet conduit 140 to the pump outlet 136, as Figure 1 shown by the arrow F in. The inlet side of the pumping stage 124 is the low-pressure (or vacuum) side, while the outlet side of the pumping stage 124 is the high-pressure side. The pump inlet 128 and / or the pump outlet 136 can include fittings as needed for fluidly connecting the pump head 102 to components external to the scroll pump 100 (e.g., conduits, chambers, etc.).

[0058] For purposes of reference and description, terms such as "axial" and "axially" are taken with respect to the drive axis D. The drive axis D can extend in either direction and is considered to be part of (or coincident with) the overall longitudinal pump axis of the scroll pump 100. For example, the "axial distance" between any two components of the scroll pump 100 is a distance that can be measured along the (extended) drive axis D in either direction (from Figure 1 the perspective of, from left to right or from right to left). From Figure 1 the perspective of, the drive axis D / pump axis is horizontal. In addition, terms such as "radial" and "lateral" are in a direction orthogonal to the axis D / pump axis, including the vertical direction from Figure 1 the perspective of. In addition, the scroll pump 100 is considered to have a front side 144 and a rear side 148. From Figure 1From this perspective, the front side portion 144 corresponds to the left side portion of the scroll pump 100, and the rear side portion 148 corresponds to the right side portion. Along the axial direction, the pump head 102 is closer to the front side portion 144 than the motor 104, and the motor 104 is closer to the rear side portion 148 than the pump head 102. In addition, the pump head 102 is considered to have an outer side portion 152 and an inner side portion 156. Along the axial direction, the outer side portion 152 is closer to the front side portion 144 than the inner side portion 156, and the inner side portion 156 is closer to the motor 104 than the outer side portion 152. Along the axial direction, the outer side portion 152 is closer to the environment (the space or environment outside the scroll pump 100). In other words, the inner side portion 156 is located deeper inside the pump head 102 than the outer side portion 152. Accordingly, any individual component of the pump head 102 (e.g., the pumping stage 124) can also be considered to have an outer side portion and an inner side portion.

[0059] The scroll pump 100 may further include an outer shroud 164 that covers all or a part of the pump head 102. The shroud 164 can be a one-piece structure or can have two or more different segments that can be attached to and detached from each other. For example, one segment of the shroud 164 can surround all or part of the pump head 102, while another segment surrounds all or part of the motor 104. Alternatively, the motor 104 can be enclosed in a motor housing (not shown) that is different from the shroud 164. The shroud and / or the motor housing can surround electrical components (e.g., circuits, wiring / cables, electrical interconnections, other electrical hardware, etc.) outside the motor 104. The shroud 164 can be made of a plastic or metal material. The shroud 164 can provide additional functions, such as preventing a user from touching the hot surfaces of the scroll pump 100, defining one or more flow paths for cooling air around and / or through the pump head 104 or an additional motor 108, etc. The shroud 164 can be attached to a tray (not shown) that covers the lower side of the pump head 104 or the additional motor 108. The scroll pump 100 may further include a suitable base or platform 168 that is configured to stably support the weight of the scroll pump 100 when the scroll pump 100 is placed on or mounted to a lower surface such as a floor, a table, a workbench, etc. The base 168 or other component(s) can be configured to dampen the vibrations generated by the scroll pump 100 during operation.

[0060] The scroll pump 100 may further include one or more cooling fans 172 to direct cooling air into thermal contact with the pump head 102 or alternatively with the electric motor 104 to carry away the dissipated heat from the scroll pump 100. In the present embodiment, the cooling fan 172 is axially positioned between the inner portion of the pumping stage 124 and the electric motor 104 within the pump frame 120. In this case, the cooling fan 172 may be mounted to the crankshaft 112 and thus powered by the crankshaft 112, as shown. The cooling fan 172 may draw in ambient air, for example, from the rear or outer side of the pump head 102 through one or more openings (vents) formed in the pump frame 120, direct the drawn-in ambient air along one or more air flow paths through the interior of the pump frame 120 (including around and in thermal contact with the pumping stage 124), and discharge the now heat-laden ambient air through one or more openings (vents) formed in the fairing 164 located at the front or inner side of the pump head 102. Figure 1 Examples of several air flow paths are depicted by arrow A. Alternatively or additionally, the fairing 164 may surround the electric motor 104 or be attached to a separate motor housing such that the air flow paths extend around the electric motor 104 and into thermal contact with the electric motor 104, and ambient air enters and / or exits the motor housing. Alternatively or additionally, the cooling fan may be located at or near the front side 144 of the scroll pump 100, such as within the interior space of the fairing 164 adjacent to the outer side of the pump head 102. In this configuration, the cooling fan may be powered by its own (electric) motor. Alternatively or additionally, if the electric motor 104 is surrounded by an extended version of the fairing 164 or by a separate motor housing, the cooling fan may be located within the enclosed interior space around the electric motor 104 to directly cool the electric motor 104 and associated electrical hardware (e.g., (one or more) circuit boards, (one or more) wire harnesses, etc.).

[0061] Figure 2A is a cross-sectional front view of an example of a pump head 202 according to an embodiment of the present disclosure. For example, the pump head 202 may be used as the pump head 102 of the scroll pump 100 shown above Figure 1 as shown. Figure 2B is a close-up view of an area of the pump head 202 described below.

[0062] Generally, the pump head 202 may include a stationary pump frame and / or pump housing (not shown) that encloses and / or supports the various components of the pump head 202. For example, the various components of the pump head 202 may be integral with or attached to the pump frame or housing. In the present embodiment, the pump head 202 is a multi-stage pump head. Specifically, the pump head 202 is a two-stage pump head and thus includes a first (or outer or upstream) pumping stage 224A and, in series with the first pumping stage 224A (with respect to the fluid flow path F, Figure 1)The fluidly connected second (or inner or downstream) pumping stage 224B. The first pumping stage 224A receives (low-pressure) working fluid from the pump inlet 128( Figure 1 ), compresses the working fluid (at least slightly), and outputs the compressed working fluid to the second pumping stage 224B. The second pumping stage 224B further compresses the working fluid and discharges the (even higher-pressure at this time) working fluid to the pump outlet 136( Figure 1 ). As shown, the total internal volume and volume displacement rate of one pumping stage (e.g., the first pumping stage 224A) can be different from those of the other pumping stage (e.g., the second pumping stage 224B).

[0063] Alternatively, the pump head 202 can be configured such that the inner pumping stage is the first pumping stage and the outer pumping stage is the second pumping stage. Alternatively, the pump head 202 can provide more than two pumping stages and / or two or more pumping stages operating in parallel. As another alternative, the pump head 202 can be a single-stage pump head.

[0064] As a two-stage pump head, the pump head 202 includes a moving scroll disk 280, which is axially interposed between the outer stationary scroll disk 284A and the inner stationary scroll disk 284B. The outer stationary scroll disk 284A and the outer portion of the moving scroll disk 280 together define the first pumping stage 224A, while the inner stationary scroll disk 284B and the inner portion of the moving scroll disk 280 together define the second pumping stage 224B. During the operation of the pump head 202, the moving scroll disk 280 eccentrically orbits about the drive axis D in a circular path at a deviation or radial distance r (in a transverse plane orthogonal to the drive axis D) from the drive axis D, as further described below.

[0065] The moving scroll disk 280 includes a moving scroll plate 288 oriented in the transverse plane, at least one outer (first) moving scroll vane 292A axially extending (or protruding) from the outer portion of the moving scroll plate 288 toward the outer stationary scroll disk 284A, and at least one inner (second) moving scroll vane 292B axially extending (or protruding) from the inner portion of the moving scroll plate 288 toward the inner stationary scroll disk 284B. The outer stationary scroll disk 284A includes a laterally oriented outer stationary scroll plate 296A and at least one outer stationary scroll vane 298A axially extending (or protruding) toward the outer portion of the moving scroll plate 288. The inner stationary scroll disk 284B includes a laterally oriented inner stationary scroll plate 296B and at least one inner stationary scroll vane 298B axially extending (or protruding) toward the inner portion of the moving scroll plate 288.

[0066] The inner stationary scroll disk 284B can be removably attached to or be integral with the aforementioned pump frame or housing. The outer stationary scroll disk 284A can be removably attached to the inner stationary scroll disk 284B (or alternatively to another stationary structure such as the pump frame 210 etc.) by suitable fastening means (e.g., in the form of bolts or screws 276 as shown in the figure etc.). The interface between the outer stationary scroll disk 284A and the inner stationary scroll disk 284B can be sealed by suitable sealing elements (such as O-rings, washers etc.) to prevent fluid leakage.

[0067] The outer moving scroll vane 292A, the inner moving scroll vane 292B, the outer stationary scroll vane 298A and the inner stationary scroll vane 298B are each helical in the transverse plane (each extending along a helical path which can be an Archimedean line, an involute etc.). Figure 2A The cross-sectional view shows that the scroll vanes 292A, 292B, 298A and 298B have turned several (e.g., four) turns or circumferences along their respective helical paths. As shown in the figure, the outer moving scroll vane 292A is juxtaposed with the outer stationary scroll vane 298A in the radial direction (orthogonal to the drive axis D), such that the outer moving scroll vane 292A and the outer stationary scroll vane 298A are positioned and nested (crossed, interdigitated or staggered) at a predetermined relative angle. Similarly, the inner moving scroll vane 292B is juxtaposed with the inner stationary scroll vane 298B in the radial direction, such that the inner moving scroll vane 292B and the inner stationary scroll vane 298B are positioned and nested at a predetermined relative angle. With this configuration, when the moving scroll disk 280 rotates relative to the outer stationary scroll disk 284A and the inner stationary scroll disk 284B, one or more variable-volume cavities are defined by the nested outer moving scroll vane 292A and outer stationary scroll vane 298A (and between them) in the first pumping stage 224A, and one or more variable-volume cavities are defined by the nested inner moving scroll vane 292B and inner stationary scroll vane 298B (and between them) in the second pumping stage 224B.

[0068] As an example, Figure 3 is a cross-sectional perspective view of the moving scroll disk 280 showing approximately half of the moving scroll disk 280. Figure 3 Shows the multi-turn helical shapes of the outer moving scroll vane 292A and the inner moving scroll vane 292B. The helical shapes of the outer stationary scroll vane 298A and the inner stationary scroll vane 298B can be similar.

[0069] As another example, Figure 4 is a cross-sectional plan view (in the transverse plane) of the second pumping stage 224B. Figure 4shows the nesting relationship between the inner orbiting scroll blade 292B and the inner stationary scroll blade 298B, and the formation of a crescent-shaped, moving, variable-volume cavity P between adjacent segments of the inner orbiting scroll blade 292B and the inner stationary scroll blade 298B (see also Figure 5 ). The second pumping stage 224B includes one or more pumping stage inlet ports located at or near the outer periphery and one or more pumping stage outlet ports located at or near the center. Generally, the working fluid enters at least one inlet port, is compressed and displaced radially inwardly towards the center, and then is discharged from at least one outlet port. For example, as the inner orbiting scroll blade 292B orbits, the rear end of a given (or first) cavity P opens to fluid communication with the inlet port and a quantity of incoming working fluid is ingested. As the inner orbiting scroll blade 292B continues to orbit, both the front and rear ends of the cavity P can become substantially closed, i.e., only very small gaps are left between adjacent points of the inner orbiting scroll blade 292B and the inner stationary scroll blade 298B at the respective front and rear ends. Additionally, the volume of the cavity P decreases, thereby (at least slightly) compressing the working fluid trapped within the cavity P. As the inner orbiting scroll blade 292B continues to further orbit, the front end of the cavity P opens and fluid communication is established with the outlet port, and the compressed working fluid is discharged from the cavity P and out through the outlet port. One or more additional cavities P can operate in the same manner at least partially simultaneously with the first cavity P.

[0070] In the present embodiment, the first pumping stage 224A includes one or more pumping stage inlet ports located at or near the center and one or more pumping stage outlet ports located at or near the outer periphery. In this configuration, the working fluid enters at least one inlet port, is compressed and displaced radially outwardly towards the outer periphery, and then is discharged from at least one outlet port. This pumping action is achieved by moving the cavity in a manner similar to that described above for the second pumping stage 224B. The working fluid is then transferred via an interconnecting fluid passage to at least one inlet port of the second pumping stage 224B.

[0071] In some embodiments, at least one of the pumping stages 224A or 224B includes more than one pair of different nested scroll blades. That is, the orbiting scroll disk 280 can include more than one different outer orbiting scroll blade 292A, and the outer stationary scroll disk 284A can include more than one different outer stationary scroll blade 298A. Alternatively or additionally, the orbiting scroll disk 280 can include more than one different inner orbiting scroll blade 292B, and the inner stationary scroll disk 284B can include more than one different inner stationary scroll blade 298B. An example of a pumping stage having three pairs of nested scroll blades is described in U.S. Patent No. 5,855,473, the entire content of which is incorporated herein by reference.

[0072] As shown Figure 2A in FIG. 2, the pump head 202 includes a crankshaft 212, which may correspond to the crankshaft 112 described above and Figure 1 shown in FIG. 2. The crankshaft 212 includes a main shaft 206 (part or section) and an eccentric shaft (part or section) or a crank 210 that is integral with or attached to the main shaft 206. The main shaft 206 extends in an outer direction from the motor side ( Figure 2A from right to left in FIG. 2) to the central hole 214 of the inner fixed scroll disk 284B. The main shaft 206 rotates directly on the drive axis D (coaxial or coincident), and this rotation is driven by the motor 104 ( Figure 1 ). One or more bearings 218 are configured to support the rotation of the main shaft 206 and / or bear the thrust generated during operation. The crank 210 extends in an outer direction from the main shaft 206 to the center (moving vortex) hole of the moving vortex hub 222 of the moving scroll disk 280. The central axis of the crank 210 (referred to as the crank axis C in Figure 2A FIG. 2) is radially offset from the central axis of the main shaft 206 (drive axis D) by the above radial distance r. Therefore, when the main shaft 206 rotates on the drive axis D, the crank 210 orbits around the drive axis D in a circular path with a radius of r. The moving scroll disk 280 is coupled to the crank 210 via one or more bearings 226 and thus orbits together with the crank 210. The bearings 226 are configured to support the orbiting of the crank 210 and the moving scroll disk 280 and / or bear the thrust generated during operation. As understood by those skilled in the art, the scroll pump 100 may further include one or more counterweights (not shown) mounted to the crankshaft 212 and / or the motor shaft 108 ( Figure 1 ), which are configured (designed in terms of size, position, etc.) to balance the forces generated by other orbiting components (e.g., the moving scroll disk 280, the crank 210, the bearings 226).

[0073] The pump head 202 is configured to constrain the movement of the moving scroll disk 280 to only orbiting movement. That is, the pump head 202 is configured to prevent the moving scroll disk 280 from rotating about its own central axis (i.e., the crank axis C). For this purpose, as understood by those skilled in the art, the scroll pump 100 may include appropriate anti-rotation devices (e.g., metal bellows, cross-slider couplings, eccentrically positioned synchronous cranks or idler shafts, etc., not shown) that interface with the moving scroll disk 280.

[0074] As Figure 2BAs best shown in, the pump head 204 also includes a stub shaft 234 removably attached (or fastened, mounted, etc.) to the outer end of the crankshaft 212 (specifically, the outer end of the crank 210). To facilitate a properly aligned engagement between the stub shaft 234 and the crank 210, the engagement end of the stub shaft 234 may include an annular boss or projection 238 that fits into a complementary-shaped recess or counterbore 242 formed in the corresponding engagement (outer) end of the crank 210. The stub shaft 234 may be attached to the crank 210 by using one or more suitable fasteners or by any other means that effectively maintains a secure engagement between the stub shaft 234 and the crank 210 during operation of the pump head 202, particularly during repeated cycles of operation of the orbiting scroll 280. In the present embodiment, the crank 210 has an axially centered crank (first) hole 246, and the stub shaft 234 has an axially centered stub shaft (second) hole 250 that aligns with the crank hole 246. To securely attach the stub shaft 234 to the crank 210, a stub shaft screw 254 passes through the stub shaft hole 250 and is threaded (screwed) into the crank hole 246. Thus, the external threads of the stub shaft screw 254 mate with the internal threads of the crank hole 246 to form a threaded engagement 258 between the stub shaft screw 254 and the crank 210, whereby the stub shaft 234 is axially clamped between the screw head 262 of the stub shaft screw 254 and the crank 210. The screw head 262 may fit within a recess or counterbore 266 in the stub shaft 234, which may serve as a mechanical stop for limiting the extent of axial translation of the stub shaft screw 254 into the crank hole 246.

[0075] In another embodiment, instead of using the stub shaft screw 254, the stub shaft 234 and the stub shaft hole 250 may be sized such that the stub shaft hole 250 can fit around the outer surface of the crank 210. In this case, the stub shaft hole 250 may have internal threads, while the outer surface of the crank 210 may have complementary external threads. Thus, in this embodiment, the stub shaft 234 may be screwed onto the crank 210 rather than into the crank 210.

[0076] In other embodiments, other types of stub shaft fasteners may be used to securely fasten the stub shaft 234 and the crank 210 together. As will be understood by those skilled in the art, examples include, but are not limited to, clamping members, radially oriented screws or pins, spring-biased balls or other engagement members, bayonet mechanisms, locking members, retainers (such as rings), magnets, etc.

[0077] In one embodiment, the short shaft 234 can be regarded as a removable portion of the crankshaft 212. In other words, the crankshaft 212 can be considered a multi-piece (multi-part) crankshaft. In the illustrated example, the crankshaft 212 can be considered an at least two-piece (two-part) crankshaft, which includes the integral main shaft 206 and crank 210 as one piece and the removable short shaft 234 as another piece.

[0078] In one embodiment, the crank 210 can be considered to include a first crank section 270 that is integral with (or attached to) the main shaft 206 ( Figure 2B ) and a second crank section (short shaft 234) that is removably attached to the first crank section 270.

[0079] In the present embodiment, the pump head 202 may further include an axial end cap or cover 274 located at the outermost end (outer side) of the short shaft 234 ( Figure 2B ). The end cap 274 can be cup-shaped as shown. The end cap 274 can be removably and at least partially installed within the orbiting scroll hub 222 and fastened by a suitable retainer 278, such as a snap ring, C-clip, etc., which expands into an annular inner groove of the orbiting scroll hub 222. The end cap 274 can provide a closed end at the outer side of the short shaft 234 and can serve as a solid barrier to prevent fluids (such as lubricants like working fluid, grease, etc.) and particles (such as dust, dirt, metal fines, plastic fines, debris, etc.) from passing through the end cap 274 in either direction. The interface between the end cap 274 and the orbiting scroll hub 222 can be sealed by a suitable sealing element (such as an O-ring, gasket, etc.) to prevent fluid and particle leakage.

[0080] Figure 5 is Figure 2A A close-up view of the areas of the illustrated pumping stages 224A and 224B. As shown, there is a small axial clearance g between the blade tips (free ends) of each of the scroll vanes 292A, 292B, 298A, and 298B and the surfaces of the scroll plates 288, 296A, and 296B that are adjacent to and face these blade tips. Specifically, there is an axial clearance g between the tip of the outer orbiting scroll vane 292A and the outer fixed scroll plate 296A, another axial clearance g between the tip of the outer fixed scroll vane 298A and the outer side of the scroll plate 288, another axial clearance g between the tip of the inner orbiting scroll vane 292B and the inner fixed scroll plate 296B, and another axial clearance g between the tip of the inner fixed scroll vane 298B and the inner side of the scroll plate 288. The axial clearance g forms a partial or substantially fluid-sealed interface that allows the formation of the above-described moving variable-volume cavities P for capturing, compressing, and transporting the working fluid without restricting the orbiting movement of the orbiting scroll disk 280.

[0081] In this embodiment, the axial clearance g is at least partially occupied or filled by the dynamic tip seals 282. The blade tips of each of the scroll vanes 292A, 292B, 298A, and 298B have grooves 286 (see also Figure 3 ), and the tip seals 282 are installed in the grooves 286 such that each groove 286 and the corresponding tip seal 282 (outer dynamic tip seal, inner dynamic tip seal, outer stationary tip seal, and inner stationary tip seal) extend along the same helical path as its corresponding scroll vane 292A, 292B, 298A, and 298B. The above-mentioned axial clearance g can be specified as the axial distance between the bottom of the groove 286 (rather than the blade tip) and the corresponding adjacent scroll plates 288, 296A, and 296B. As an example, the axial clearance g can be on the order of thousandths of an inch (e.g., less than 10), e.g., in the range of 0.001 inches to 0.002 inches, or about 0.025 millimeters to about 0.051 millimeters. The tip seals 282 can each have a one-piece construction made of an elastomeric polymer, such as natural or synthetic rubber (e.g., closed-cell foam rubber), etc. Alternatively, the tip seals 282 can each have a two-piece construction that includes an elastic (springy) layer located at the bottom of the groove 286 and a wear-resistant layer (e.g., a polytetrafluoroethylene (PTFE)-based material) disposed on the elastic layer and extending out of the groove 286.

[0082] The tip seals 282 can enhance the sealing interface between the orbiting scroll disk 280 and the stationary scroll disks 284A and 284B. During operation of the pump head 202, particularly during the orbiting motion of the orbiting scroll disk 280, the tip seals 282 prevent direct contact between the blade tips of the scroll vanes 292A, 292B, 298A, and 298B and the corresponding adjacent scroll plates 288, 296A, and 296B. During the orbiting motion, the tip seals 282 are typically located on a thin layer of working fluid (or "buffer layer") between the blade tip and the corresponding scroll plates 288, 296A, and 296B, which is formed due to the pressure difference between the two sides of a given scroll vane 292A, 292B, 298A, and 298B. Due to exposure to friction and heat, over time, the tip seals 282 will eventually wear out with the operation of the pump, which will reduce the sealing effect of the tip seals 282 and thus reduce the pumping performance of the pumping stages 224A and 224B (e.g., the ability to generate and maintain a vacuum). Therefore, the service life of the tip seals 282 is limited and they need to be replaced regularly as part of a regular maintenance program.

[0083] The dimension (axial distance) of the axial clearance g affects the sealing effect of the tip seal 282, thereby affecting the pumping performance. The axial clearance dimension depends on the axial position of the orbiting scroll disk 280 relative to the fixed scroll disks 284A and 284B. In the case of a two-stage scroll pump as in the present embodiment, it may be desirable to set the axial position of the orbiting scroll disk 280 such that the axial clearance dimension on the outer side is equal to (or substantially equal to) the axial clearance dimension on the inner side of the orbiting scroll disk 280, or, alternatively, to set the axial position of the orbiting scroll disk 280 to set a specific axial clearance on the respective outer and inner sides. In the latter case, depending on the requirements of a particular embodiment, the specific axial clearance dimension on the outer side may be equal to or different from the specific axial clearance dimension on the inner side. That is, moving the axial position of the orbiting scroll disk 280 in the outer direction decreases the axial clearance dimension on the outer side while increasing the axial clearance dimension on the inner side. Similarly, moving the axial position of the orbiting scroll disk 280 in the inner direction increases the axial clearance dimension on the outer side while decreasing the axial clearance dimension on the inner side.

[0084] In the present embodiment, as Figure 2B best shown, the pump head 202 includes an adjusting nut 290 configured to control (adjust or set) the axial position of the orbiting scroll disk 280, thereby controlling the axial clearance dimension. The adjusting nut 290 is axially adjustable relative to the short shaft 234. To this end, the adjusting nut 290 may be directly engaged with the short shaft 234. For example, in the present embodiment, the adjusting nut 290 is threadedly connected (screwed) to the short shaft 234 such that the adjusting nut 290 is axially positioned between the end cap 274 and the outermost bearing 226, which at least partially serves to couple the crank 210 and the orbiting scroll disk 280. In other words, the internal threads of the adjusting nut 290 cooperate with the external threads of the short shaft 234 to form a threaded engagement 203 between the adjusting nut 290 and the short shaft 234. Thus, rotation of the adjusting nut 290 causes the adjusting nut 290 to axially translate, thereby adjusting its axial position along the length of the short shaft 234. The threads may be of a fine pitch to allow for very small, precise adjustments in the axial direction. In a specific example, the adjusting nut 290 may be (or have a similar configuration to) a lock nut commercially available from Spieth-Maschinenelemente GmbH&Co.KG of Esslingen, Germany.

[0085] The adjusting nut 290 is configured to contact a surface that is coupled to or integral with the orbiting scroll disk 280 (e.g., within the orbiting scroll hub 222), such that axial adjustment of the adjusting nut 290 adjusts the axial position of the orbiting scroll disk 280 relative to the fixed scroll disks 284A and 284B. In the present embodiment, the adjusting nut 290 is mounted to the short shaft 234 such that the adjusting nut 290 abuts the outermost surface 207 (outer side surface) of the outermost bearing 226 that is coupled to the orbiting scroll disk 280, specifically, the outer side surface of the inner race of the outermost bearing 226. The inner diameter of the outermost bearing 226 is sized such that the outermost bearing 226 is slidably fitted onto the crank 210, thereby allowing the outermost bearing 226 to axially translate along the length of the crank 210 in response to an applied force. The outermost bearing 226 is preloaded with a spring biasing force applied in an outer side direction (e.g., toward the adjusting nut 290) by one or more other components within the orbiting scroll hub 222 (such as one or more spring washers, bent disk springs, wave washers, Belleville springs, etc.). With this configuration, after the adjusting nut 290 contacts the outermost surface 207 of the outermost bearing 226, further rotation of the adjusting nut 290 in one direction will overcome the spring biasing force, causing the outermost bearing 226 to axially translate further in an inner side direction (toward the Figure 2A and Figure 2B right side in Figure 2A and Figure 2B ), thereby also causing the orbiting plate 280 (e.g., by sliding on the crank 210) to axially translate in an inner side direction relative to the fixed scroll disks 284A and 284B. On the other hand, due to the outwardly directed spring biasing force, rotation of the adjusting nut 290 in the opposite direction will cause the outermost bearing 226 to axially translate in an outer side direction (toward the

[0086] left side in Figure 6 and Figure 6 ), thereby also causing the orbiting plate 280 to translate in an outer side direction relative to the fixed scroll disks 284A and 284B.

[0086] Additionally refer to Figure 6 and Figure 6Is a perspective view of an example of an adjusting nut 290. The adjusting nut 290 is mainly defined by an annular body 611, and the annular body 611 includes an annular outer surface 615 and an annular inner surface 619. An annular outer groove 623 is formed in the outer surface 615 and divides the outer surface 615 into two segments. An annular inner groove 627 is formed in the inner surface 619 and divides the inner surface 619 into two segments, each segment including an internal thread, and the external thread on the short shaft 234 is configured to cooperate with this internal thread. Axially oriented locking screws 631 (e.g., four) equally spaced around the circumference of the annular body 611 are threadedly connected into corresponding threaded holes formed in the annular body 611. Once the adjusting nut 290 has been translated to its selected axial position on the short shaft 234, the locking screws 631 are tightened to deform the annular outer groove 623 and the annular inner groove 627, thereby deforming the annular body 611 as well and applying a clamping force to the short shaft 234 (especially the external thread of the short shaft 234) to lock the adjusting nut 290 in place at the selected axial position. The annular body 611 may also include a set of blind holes 635 configured to engage an appropriate tool facilitating rotation (screwing) of the adjusting nut 290 on the short shaft 234.

[0087] In particular, compared with a scroll pump of a known configuration, the short shaft 234 and its removability from the crank 210 can provide one or more advantages. For example, the short shaft 234 can make it easier to disassemble the pump head 202 and, thereby, easier to access the internal components of the pump head 202, such as the orbiting scroll 280, the inner stationary scroll 284B, the tip seal 282, one or more bearings 226, etc. Due to the short shaft 234, accessing such internal components may only require partial disassembly of the pump head 202 and less disassembly than in previously known scroll pumps. Then, these internal components can be repaired (e.g., cleaned, re-lubricated, repaired, etc.) or replaced as needed.

[0088] Now will mainly refer to Figure 2A and Figure 2B Describe an example of partially disassembling the pump head 202. First, remove any components covering the outside of the pump head 202 (e.g., Figure 1The fairing 164 shown, if provided, and any other covers, lids, etc.). Next, the outer fixed scroll disk 284A is disassembled (e.g., loosened) and removed from the inner fixed scroll disk 284B (or from another stationary structure of the pump head 202, depending on the embodiment). At this time or later, if needed, the tip seal 282 of the outer fixed scroll disk 284A can be removed and replaced with a new tip seal, and / or the outer fixed scroll disk 284A can be otherwise serviced (e.g., cleaned, repaired, etc.) or replaced. For example, the tip seal groove 286 of the outer fixed scroll disk 284A can be cleaned before installing a new tip seal. Then access the short shaft 234. In this embodiment, the short shaft 234 is accessed by first removing the retainer 278 (using a suitable tool, such as a snap ring pliers) and then removing the end cap 274. If needed, the O-ring of the end cap 274 can be replaced. Then, by loosening and removing the short shaft screw 254 (or any other type of fastener provided), the short shaft 234 can be disassembled and removed from the crank 210. Then the orbiting scroll disk 280 is removed, which is made easier by providing the removable short shaft 234. Depending on the embodiment, it may be necessary to remove the outermost bearing 226 before removing the entire orbiting scroll disk 280. Depending on the embodiment, tools may or may not be needed to assist in removing the outermost bearing 226, other bearings, or other annular components around the crank 210. At this time or later, if needed, the outer and inner tip seals 282 of the orbiting scroll disk 280 can be removed and replaced with new tip seals, and / or the orbiting scroll disk 280 can be otherwise serviced (e.g., cleaned, repaired, etc.) or replaced. For example, the tip seal groove 286 of the orbiting scroll disk 280 can be cleaned before installing new tip seals. Additionally, if needed, any components located within the orbiting scroll hub 222 and / or on or around the crank 210 (e.g., bearings 226, shims, sleeves, washers, springs, shaft seals, etc.) can be serviced or replaced.

[0089] In some embodiments, the orbiting scroll disk 280 can have a multi-piece construction. In this embodiment, removing the multi-piece orbiting scroll disk from the crank 210 does not require disassembling the multi-piece orbiting scroll disk. Instead, the entire multi-piece orbiting scroll disk can be removed as a single-piece component.

[0090] Removing the orbiting scroll disk 280 not only provides access to the inner portion of the orbiting scroll disk 280 but also provides access to the inner fixed scroll disk 284B from the outer portion of the pump head 202. Removing the orbiting scroll disk 280 exposes the inner fixed scroll disk 284B at the outer portion of the pump head 202. Thus, accessing the inner fixed scroll disk 284B does not require disassembling and removing the inner fixed scroll disk 284B from the pump frame or housing, and such access also does not require removing the crankshaft 212, shaft coupling 116 ( Figure 1) Remove and / or detach any other components on the inner fixed scroll disk 284 or the inner portion of the pump head 202, such as the motor shaft 108, the motor 104, etc. With the orbiting scroll disk 280 removed, the tip seal 282 of the inner fixed scroll disk 284B is then removed and replaced with a new tip seal, and if necessary, the tip seal groove 286 of the inner fixed scroll disk 284B can be cleaned. After the maintenance is completed, the reassembly of the pump head 202 may require steps that are substantially the reverse of the above-described disassembly steps.

[0091] When the pump head 202 includes the above-described adjusting nut 290, the removability of the short shaft 234 and its connection to the crank 210 can be particularly useful. Advantageously, with the configuration of the embodiments disclosed herein, the short shaft 234 can be reliably and repeatedly removed from the crankshaft 212 (specifically, the crank 210), and then reattached to the crankshaft 212 (specifically, the crank 210) at the same exact axial position as before. In particular, the short shaft 234 can be removed and precisely reattached without the need to move (rotate / translate) the adjusting nut 290 relative to the short shaft 234 or remove the adjusting nut 290 from the short shaft 234. Thus, the short shaft 234 can be removed and reattached without disturbing the setting of the axial position of the adjusting nut 290. That is, the short shaft 234 and the adjusting nut 290 can be removed and reinstalled substantially together as an integral or single-piece component or assembly. In other words, during removal and reinstallation, the adjusting nut 290 remains locked in place on the short shaft 234. This also means that the internal components of the pump head 202, such as the orbiting scroll disk 280, the tip seal 282, the bearing 226, etc., can be removed, then reinstalled or replaced without disturbing the setting of the adjusting nut 290. Therefore, after reinstalling or replacing one or more internal components, the reattachment of the short shaft 234 to the crankshaft 212 automatically restores the pre-existing (preset) axial position of the adjusting nut 290, thereby automatically restoring the pre-existing axial position of the orbiting scroll disk 280 relative to the fixed scroll disks 284A and 284B, without the need to take any measurements or perform any advanced procedures. This configuration is particularly advantageous when the pre-existing axial position is the original axial position specified and set by the factory for the pump head 202 or the entire scroll pump 100 (which is often the case).

[0092] In other words, before removing the stub shaft 234 from the crank 210, the adjusting nut 290 engages the stub shaft 234 at a preset (e.g., factory-set) axial position on the stub shaft 234. Subsequently, the adjusting nut 290 and the stub shaft 234 can be removed from the crank 210 as an assembly without changing the preset axial position of the adjusting nut 290 on the stub shaft 234. Before removing the stub shaft 234 from the crank 210, the adjusting nut 290 can be located in a position that prevents the removal of the orbiting scroll 280 from the crank 210. However, after removing the adjusting nut 290 and the stub shaft 234 together from the crank 210, the orbiting scroll 280 can be removed from the crank 210.

[0093] Figure 7 is a cross-sectional front view of an example of a region of a pump head 202 similar to Figure 2B according to another embodiment of the present disclosure. This embodiment includes a stub shaft 734, with a stub shaft screw (or other type of fastener) integral with the stub shaft 734. The stub shaft 734 can include a head 742 and a threaded (screw) portion 754 having external threads (or can include another type of fastener portion). The head 742 can include a socket 746 configured to receive a suitable tool (e.g., a hex wrench) for rotating the stub shaft 734 and thereby threadedly connecting the stub shaft 734 to the crank 210.

[0094] Figure 8A is a cross-sectional front view of an example of a region of a pump head 202 similar to Figure 2B according to another embodiment of the present disclosure. In this embodiment, at the outer end of the crank 210 where the stub shaft 234 is attached, a circumferential buffer portion 850 is formed or included around the outer surface of the crank 210. Compared to the rest of the crank 210, the buffer portion 850 constitutes a section with a reduced outer diameter. As an example, the outer diameter of the buffer portion 850 can be in the range of 80% to 99% or 95% to 99% of the outer diameter of the rest of the crank 210. As Figure 8AAs shown in this and other figures, various types of annular members can surround the crank 210 inside the orbiting scroll hub 222. One or more of these annular members can be installed onto the crank 210 as a sliding fit, thereby defining a radial clearance between the annular member and the crank 210. One or more annular members can directly surround the buffer portion 850. In the present embodiment, at least a portion of the inner race of the outermost bearing 226 directly surrounds the buffer portion 850. Due to the reduced diameter of the buffer portion 850, the radial clearance between the buffer portion 850 and the outermost bearing 226 is greater than the radial clearance between the remaining portion of the crank 210 (the remainder of the crank 210) and the other annular members. In other words, the radial clearance includes an enlarged radial clearance section 839 defined between the buffer portion 850 and the annular member directly surrounding the buffer portion 850 (the outermost bearing 226 in this example), and this enlarged radial clearance section 839 is greater than the remainder of the radial clearance. In the current case, if no other annular members are radially positioned between a portion of the inner surface and the crank 210, this portion of the inner surface of the orbiting scroll hub 222 can be considered an "annular member".

[0095] Figure 8B FIG. is a perspective view of the crank 210 also showing the buffer portion 850.

[0096] When the threaded joint between the short shaft 234 and the crank 210 is tightened, due to the compressive stress applied to the crank 210, the outer diameter of the crank 210 will expand according to Poisson's ratio. In most cases, due to the tight running clearance between the scroll disks 280, 284A, and 284B, a tight sliding fit is established between the outer diameter of the crank 210 and the inner diameters of the orbiting scroll bearing 226 and the other annular members. Therefore, this small expansion of the crank 210 caused by the tightening of the short shaft screw 254 may cause the crank 210 to expand to a sufficient extent that it becomes difficult or even impossible to assemble the orbiting plate 280 onto the crank 210. To compensate for this expansion, as shown, a buffer portion 850 can be provided at the end of the crank 210 to avoid an interference fit between the crank 210 and the orbiting scroll bearing 226 after the short shaft screw 254 is tightened. The buffer portion 850 can also be provided in any other embodiment of the pump head 202 disclosed herein.

[0097] The embodiments specifically shown in the drawings mainly relate to two-stage (or more generally, multi-stage) vortex pumps. However, the subject matter disclosed herein is equally applicable to single-stage vortex pumps. A single-stage vortex pump has a pair of nested vortex disks. For example, a single-stage vortex pump may have a moving vortex disk with vortex blades only on the outer side, which is nested with a single stationary vortex disk located outside the moving vortex disk. Alternatively, a single-stage vortex pump may have a moving vortex disk with vortex blades only on the inner side, which is nested with a single stationary vortex disk located on the inner side of the moving vortex disk. The subject matter is particularly useful in the latter case, i.e., a single inwardly positioned pumping stage. This is because, as described above, the subject matter enables the easy removal of the moving vortex disk from the outside of the pump head, thereby accessing the pump components located inside the moving vortex disk.

[0098] For example, the vortex pumps disclosed herein can operate at pumping speeds of 10 L / min to 1000 L / min or 50 L / min to 500 L / min. For example, the vortex pumps disclosed herein can produce a final vacuum of from 5 x 10 -1 mbar (3.75 x 10 - 1 Torr) to 15 x 10 -3 mbar (11.25 x 10 -1 Torr), or from 3 x 10 -1 (2.25 x 10 -1 Torr) to 9 x 10 -3 mbar (6.75 x 10 -1 Torr).

[0099] It should be understood that terms such as "in communication with" and "in communication with" (e.g., a first component is "in communication with" or "in communication with" a second component) and "coupled to" or "coupled with" are used herein to indicate a structural, functional, mechanical, electrical, signal, magnetic, electromagnetic, ionic, or fluid relationship between two or more components or elements. Thus, the fact that a component is said to be in communication with or coupled to a second component does not purport to exclude the possibility that additional components may be present between the first and second components and / or operably associated with or engaged to the first and second components.

[0100] It should be understood that various aspects or details of the present invention may be changed without departing from the scope of the invention. Additionally, the foregoing description is for illustrative purposes only and not for purposes of limitation - the present invention is defined by the claims.

Claims

1. A vortex pump head, comprising: a pumping stage including an orbiting scroll and a non-orbiting scroll nested together, wherein the orbiting scroll is configured to orbit about a drive axis relative to the non-orbiting scroll to form a moving pocket between the orbiting scroll and the non-orbiting scroll that is effective to pump fluid from a pump inlet to a pump outlet; a crankshaft comprising a main shaft rotatable about the drive axis and a crank radially offset from the drive axis and coupled to the orbiting scroll, wherein the crank is configured to drive the orbiting scroll to orbit about the drive axis in response to rotation of the main shaft; and A stub axle is removably attached to the crank.

2. The vortex pump head according to claim 1, wherein: The orbiting scroll includes an orbiting scroll hole, and the stub shaft is disposed in the orbiting scroll hole when removably attached to the crank. 3 . The scroll pump head of claim 1 , comprising a stub shaft fastener configured to removably attach the stub shaft to the crank.

4. The vortex pump head according to claim 3, wherein: The stub shaft fastener is detached from the stub shaft.

5. The vortex pump head according to claim 3, wherein: The stub shaft fastener is integral with the stub shaft.

6. The vortex pump head according to claim 3, wherein: The crank includes crank threads, and the stub shaft fastener includes stub shaft threads configured to engage the crank threads.

7. The vortex pump head according to claim 3, wherein: The crank includes a crank axial bore having internal threads, and the stub fastener includes a stub screw having external threads configured to engage the internal threads.

8. The vortex pump head according to claim 1, wherein: The crank includes a crank end adjacent to the stub shaft and a buffer portion disposed at the crank end, and the buffer portion has an outer diameter reduced compared to an outer diameter of a remaining portion of the crank.

9. A vortex pump head according to claim 8, comprising an annular member surrounding the crank so that a radial gap is defined between the crank and the annular member, wherein: The radial gap includes an enlarged radial gap section defined between the buffer portion and the annular member, and the enlarged radial gap section is larger than a remaining portion of the radial gap.

10. The vortex pump head according to claim 1, wherein: The orbiting scroll has an outer portion and an inner portion, and along the axial direction relative to the drive axis, the outer portion is closer to the environment outside the scroll pump head than the inner portion; The fixed scroll is an inner fixed scroll, the pumping stage is an inner pumping stage, the inner pumping stage comprises the inner fixed scroll and the inner portion of the orbiting scroll, the orbiting scroll and the inner fixed scroll are nested together on the inner portion; and The outer portion blocks access to the inner portion and the inner fixed scroll in a direction from the outer portion toward the inner portion.

11. The vortex pump head according to claim 10, wherein: The orbiting scroll includes an inner orbiting tip seal, the inner non-orbiting scroll includes an inner non-orbiting tip seal, and the outer portion blocks access to the inner orbiting tip seal and the inner non-orbiting tip seal in a direction from the outer portion toward the inner portion.

12. A scroll pump head according to claim 10, comprising an outer pumping stage, said outer pumping stage comprising an outer fixed scroll and said outer portion of said orbiting scroll, wherein: The movable scroll and the outer fixed scroll are nested together on the outer side; and The orbiting scroll is configured to orbit about the drive axis relative to the outer fixed scroll to form a moving pocket on the outer side portion between the orbiting scroll and the outer fixed scroll.

13. The vortex pump head according to claim 12, wherein: The orbiting scroll includes an inner orbiting tip seal and an outer orbiting tip seal, the inner fixed scroll includes an inner fixed tip seal, and the outer fixed scroll includes an outer fixed tip seal; and The outboard portion inhibits access to the inboard dynamic tip seal and the inboard fixed tip seal in a direction from the outboard portion toward the inboard portion.

14. The vortex pump head according to claim 1, comprising an adjusting nut capable of being axially adjusted relative to the short shaft, wherein: The adjustment nut is configured to contact a surface coupled to or integral with the orbiting scroll, and axial adjustment of the adjustment nut adjusts an axial position of the orbiting scroll relative to the fixed scroll.

15. The vortex pump head according to claim 14, wherein: The adjusting nut engages with the stub shaft at a predetermined axial position on the stub shaft, and the adjusting nut and stub shaft can be removed from and reinstalled to the crank together as an assembly without changing the predetermined axial position.

16. The vortex pump head according to claim 15, wherein: The adjustment nut includes adjustment nut threads, and the stub shaft includes stub shaft threads configured to engage the adjustment nut threads.

17. The vortex pump head according to claim 15, wherein: The adjusting nut is located in a position that prevents the orbiting scroll from being removed from the crank.

18. A method for maintaining a vortex pump head, the method comprising: The vortex pump head is provided, and the vortex pump head comprises: a pumping stage including an orbiting scroll and a non-orbiting scroll nested together, wherein the orbiting scroll is configured to orbit about a drive axis relative to the non-orbiting scroll to form a moving pocket between the orbiting scroll and the non-orbiting scroll that is effective to pump fluid from a pump inlet to a pump outlet; a crankshaft comprising a main shaft rotatable about the drive axis and a crank radially offset from the drive axis and coupled to the orbiting scroll, wherein the crank is configured to drive the orbiting scroll to orbit about the drive axis in response to rotation of the main shaft; and a stub shaft removably attached to the crank; removing the stub shaft from the crank; and The orbiting scroll is removed from the crank.

19. The method according to claim 18, comprising at least one of the following: Prior to removing the orbiting scroll, the orbiting scroll blocks access to an inner component of the scroll pump head, and the method further comprises repairing or replacing the inner component after removing the orbiting scroll; The orbiting scroll includes an orbiting tip seal, and the fixed scroll includes a fixed tip seal; before removing the orbiting scroll, the orbiting scroll blocks access to the orbiting tip seal and the fixed tip seal; and the method also includes replacing at least one of the orbiting tip seal or the fixed tip seal with a new tip seal after removing the orbiting scroll.

20. The method of claim 18, comprising at least one of the following: The vortex pump head includes an adjusting nut that can be axially adjusted relative to the short shaft, and before the short shaft is removed, the adjusting nut is located at a preset axial position relative to the short shaft; The vortex pump head comprises an adjusting nut which can be axially adjusted relative to the short shaft, and before the short shaft is removed, the adjusting nut is located at a preset axial position relative to the short shaft, wherein: Removing the stub shaft includes removing the adjustment nut and the stub shaft as an assembly without changing the preset axial position; The vortex pump head includes an adjusting nut that can be axially adjusted relative to the short shaft, and before removing the short shaft, the adjusting nut is located at a preset axial position relative to the short shaft, wherein removing the short shaft includes removing the adjusting nut together with the short shaft as a component without changing the preset axial position; and also includes, after removing the adjusting nut together with the short shaft, reinstalling the adjusting nut together with the short shaft by reattaching the short shaft to the crank, wherein the preset axial position of the adjusting nut on the short shaft determines the axial position of the movable scroll relative to the fixed scroll, and the reattachment restores the axial position of the movable scroll relative to the fixed scroll corresponding to the preset axial position.

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