Impeller system with inserts, inserts therfor and related methods

Abstract

A system is disclosed. The system includes an impeller having a plurality of chambers defining vanes of the impeller. One or more of the plurality of chambers each have at least one attachment portion. One or more inserts are provided for attaching to one or more of the attachment portions. Embodiments of inserts are also disclosed.

Description

IMPELLER SYSTEM WITH INSERTS, INSERTS THERFOR AND RELATED METHODSFIELD

[0001] The present disclosure relates to impellers and corresponding inserts for the impeller. In particular, embodiments of the present disclosure relate to impellers for liquid ring compressors or liquid ring vacuum pumps and inserts that permit varying the compression ratio and / or volumetric capacity thereof.BACKGROUND

[0002] Impellers are rotors used in a variety of applications to increase the pressure and / or flow of a fluid, thereby imparting energy to the fluid. Impellers come in a wide variety of designs and configurations known in the art and are used in a wide variety of applications, such as pumps and compressors.

[0003] Within a liquid ring compressor or liquid ring pump, a vaned impeller is positioned eccentrically within a casing or stator housing. On start up, the housing is filled with a predefined volume of liquid, typically water. As the impeller rotates, the liquid is forced against the stator housing by centripetal forces, creating a sealing ring. The eccentricity of the impeller causes the volume within the rotating vanes to vary as the impeller makes a revolution. In this manner, gases may be drawn into the vanes, compressed and expelled.

[0004] The amount of compression and volumetric capacity of the compressor can be expressed as the Compression Ratio (CR) and Volumetric Capacity (VC). CR and VC, along with other parameters, including gas composition and mechanical efficiency, relate to the power required by the compressor. Commercially available impellers for liquid ring compressors are sold with rated CRs within a certain range. If a user desires to alter or adjust the CR of the compressor due to process requirements, their options are limited.

[0005] Thus, it may be desirable to provide users with a greater range of options for adjusting the CR and VC of an impeller.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Embodiments will be described, by way of example only, with reference to the accompanying figures wherein:

[0007] Fig. l is a perspective view of an impeller including inserts according to embodiments of the present disclosure.

[0008] Fig. 2 is a cross-sectional view of the impeller of Fig. 1 taken along line 2-2 in Fig. 1.

[0009] Fig. 3 is a cross-sectional view of the impeller of Fig. 1 taken along line 3-3 in Fig. 1.

[0010] Fig. 4 is an enlarged view of the portion identified in Fig. 3.

[0011] Fig. 5 is an enlarged view of an embodiment of attachment means according to the present disclosure for an insert within a chamber of the impeller of Fig. 1.

[0012] Fig. 6 is a front perspective view of an embodiment of an insert according to the present disclosure.

[0013] Fig. 7 is a rear perspective view of the insert of Fig. 6.

[0014] Fig. 8 is a schematic view showing a rake angle of an embodiment of an insert according to the present disclosure.

[0015] Fig. 9 is a front perspective view of another embodiment of an insert according to the present disclosure.

[0016] Fig. 10 is an impeller including inserts according to the embodiment of Fig. 9.

[0017] Fig. 11 is a partial cross sectional view taken along line 11-11 in Fig. 10.

[0018] Fig. 12 is a schematic view of another embodiment of an insert according to the present disclosure.

[0019] Fig. 13 is a perspective view of another embodiment of an impeller according to the present disclosure.

[0020] Fig. 14 is a perspective view of the impeller of Fig. 13 with a further embodiment of an insert according to the present disclosure attached thereto.

[0021] Fig. 15 is a perspective view of the insert shown in Fig. 14.

[0022] Fig. 16 is a cross-sectional view taken along line 16-16 in Fig. 15.

[0023] Fig. 17 is a cross-sectional view taken along line 17-17 in Fig. 14.DETAILED DESCRIPTION

[0024] Liquid Ring Compressors (LRC) and Liquid Ring Vacuum Pumps (LRVP) have been used for vapor recovery applications in the petrochemical, refinery, and pulp & paper industries due to their high reliability and, most importantly, their ability to deal with harsh process environments that involve difficult applications with toxic and corrosive mixtures of gases and liquids.

[0025] LRC / LRVPs are considered positive displacement or “fixed” volume machines. The casing and impeller components on each compressor model / type are of a fixed shape, geometry and size.

[0026] The machine flow capacity is typically controlled externally by using speed control and / or recycle. As such, one LRC / LRVP model will deliver the same throughput volumetric capacity (VC) as any other identical model while operating on the same process conditions.

[0027] In order to optimize machine performance, Original Equipment Manufacturers (OEMs) may be able to tailor (usually on a case-by-case basis) the LRC / LRVP casing eccentricity to adjust volumetric capacity based on the desired flow and process requirements.

[0028] As such, LRC machines are built with a factory-set CR and VC, where these are is set by the gas distribution nozzle and casing eccentricity. For example, one known design uses a 6 degree cone distributor while other examples use cylindrical or port plate distributors.

[0029] According to embodiments of the present disclosure, inserts are provided that may be fixed or removably attached to an interior portion of one or more chambers of an impeller to alter the volume thereof, thereby altering the CR and VC of the impeller.

[0030] In some embodiments, the inserts are configured to be removably attached such that a user may replace worn inserts or replace inserts with inserts of different dimensions, or remove inserts altogether, to alter the performance of the impeller to meet the needs of changing process conditions and requirements.

[0031] In some embodiments, the inserts may be configured as Fixed Volume Inserts (FVIs) in which an insert occupies a pre-defined, fixed volume within the impeller chamber that does not substantially change during operation of the impeller.

[0032] In some embodiments, the inserts may be configured as Variable Volume Inserts (VVIs) in which the volume occupied by an insert within the impeller chamber is capable of being varied in response to a predetermined increase of pressure within the chamber; for example, in response to a slug of liquid entering the chamber during vapor recovery, which results in the chamber filling with an incompressible fluid.

[0033] One benefit of inserts according to embodiments of the present disclosure may be that the insert may be customizable to the user’s requirements, while reducing inefficiencies by matching or improving on existing chamber geometry. For example, in some embodiments, additive or subtractive manufacturing techniques, such as 3D printing and / or machining, may be used to obtain precise insert volumes that provide the desired specifications while reducing the likelihood of power loss or inefficiencies because the inserts can conform to existing impeller chamber geometry (e.g. predefined curvatures and / or rake angle).

[0034] Embodiments of inserts according to the present disclosure may be implemented in impellers whose chambers have been ported, i.e. where subtractive manufacturing techniques (e.g. CNC machining) were used to remove excess material from chambers of the impeller as compared to an OEM impeller.

[0035] Another benefit of inserts according to embodiments of the present disclosure, may be that the insert may be removed or replaced to alter the performance characteristics of the compressor.

[0036] Another benefit of inserts according to embodiments of the present disclosure, specifically VVIs, may be that the insert may be capable of absorbing some or all of an excess pressure within the impeller chamber that exceeds a pre-defined threshold. For example, embodiments may be configured to permanently or temporarily change the volume that they occupy in response to a slug of liquid that enters the impeller.

[0037] Sudden physical alteration to the seal ring by upsets will negatively affect the machine, causing increase in vibration and absorbed power, therefor reducing performance and capacity. Moreover, once the ring shape has been disturbed from its original shape, it usuallycannot be undone unless the machine is stopped and started again under normal operating conditions.

[0038] Embodiments of VVIs according to the present disclosure may at least partially alleviate such issues by modulating and / or absorbing the pressure spike otherwise generated as the fluids undergo compression i.e. avoiding hydro-locking of the impeller blades which may eventually fail from fatigue.

[0039] Another benefit of inserts according to embodiments of the present disclosure may be that the inserts may be configured to take up volume within the liquid ring, thereby reducing the required volume of liquid ring fluid present inside the machine and reducing the power required to operate the LRC / LRVP.

[0040] Thus partially or fully submerging the inserts within the sealing liquid ring may improve the mechanical efficiency of the compressor.

[0041] Given the pressures of the ring fluid in the LRC / LRVP, which may be in the range of 0 to 200 PSI, or possibly higher, depending on the machine model and speed, embodiments of the present disclosure may resist such hydraulic pressures of the ring fluid. Moreover, embodiments of the present disclosure may allow for an increase in volume within the compression chamber in case of a pressure spike (upset) anywhere above operating pressure, while sustaining the hydraulic pressure of the liquid ring.

[0042] Inserts according to embodiments of the present disclosure may be manufactured according to known methods, including additive and / or subtractive manufacturing techniques, such as 3D printing and / or machining. Injection moulding may also be used. Inserts according to embodiments of the present disclosure may be made of a variety of materials. The inventors have found that polymers such as NylonTM or high strength, chemically resistant thermoplastics such as PEEK or PEKK are well suited. Metals, such as steel, for example, 316L steel, may also be used.

[0043] Referring to the Figures, an impeller 10 is shown. The impeller 10 is a one-stage impeller having a first half 12 and a second half 14. However, embodiments and principles of the present disclosure are equally applicable to two or higher stage rotors, such as impellers, and the depiction of a one-stage impeller is merely exemplary.

[0044] Each half 12 and 14 comprises impeller chambers 16 and 18, respectively.Namely, the first half 12 comprises chambers 16 while the second half 14 comprises chambers18. Each chamber 16 is configured substantially the same and each chamber 18 is configured substantially the same.

[0045] In the illustrated embodiment, the inserts 20 are shown inserted and attached to chambers 16 of the first half 12. Namely, one insert 20 is shown inserted and attached to each chamber 16.

[0046] The impeller 10 includes a mounting portion 22 which receives a shaft (not shown) on which the impeller 10 is mounted and rotated during operation.

[0047] Each of the chambers 16, 18 has a first opening 24 at a radially exterior end thereof which, in operation, would be submerged within the liquid sealing ring within the stator. Each of the chambers 16, 18 also has a second opening 26, at an opposite end of the chamber from the first opening at a radial interior end thereof. As seen in the cross-section of Fig. 3, the radially interior ends 26 of the chambers 16, 18 are arranged along the surface of a frusto-conical void 28. The void 28 receives a cone (not shown) having inlet and outlet ports arranged thereon for feeding and receiving gas to be compressed by the impeller 10.

[0048] Between the ends 24, 26 each of the chambers 16, 18 is defined by curved chamber walls. Namely, each chamber 16 is defined by a pair of opposing end walls 30, 32 and a pair of opposing side walls 34, 36. The walls 30, 32, 34, 36 are curved and merge into each other to form a desired geometry and chamber volume. Side walls 34, 36 form the vanes of the impellers between the chambers 16. Similarly, each chamber 18 is defined by end walls 30, 33 and a pair of opposing side walls 35, 37. Side walls 35, 37 form the vanes of the impeller between the chambers 18. In the illustrated embodiments, the end wall 30 is common between the two halves of the impeller and therefore referred to as one of the end walls for each of chambers 16 and 18. In other embodiments, chambers 16 and 18 may not share an end wall.

[0049] In each chamber 16 containing an insert 20 there is provided an attachment portion 38 for attaching the insert 20. In the illustrated embodiment, the attachment portion 38 is configured as an outcropping or boss mount that extends from end wall 30. The attachment portion 38 is integral with the end wall 30 and thus chamber 16. As shown best in Fig. 5, the attachment portion 38 is configured as a generally rectangular prism forming an outcropping from the side wall 30. The attachment portion 38 includes a front surface 40, side surfaces 42 and 44, and a top surface 46. The surfaces 40, 42, 44 and 46 merge smoothly and continuouslywith the surrounding end wall 30. Similarly, the edges between the surfaces 40, 42, 44, and 46 are rounded at intersection of end wall 30 to reduce stress points.

[0050] Other shapes for the attachment portion are possible, such as spherical or other geometries.

[0051] A bore 48 extends from the top surface 46 into an interior of the attachment portion 38 for receiving a fastener, such as a bolt 50, for attaching the insert 20 to the attachment portion 38. The bore 48 has a central bore axis A that extends substantially parallel to the front surface 40 of the attachment portion.

[0052] The attachment portion 38 may be produced by various additive or subtractive manufacturing techniques, for example by machining from a forged billet.

[0053] Embodiments of an insert 20 will now be described in greater detail. A first embodiment of the insert 20 includes an insert body 52 having a front face 54, a top face 55, side faces 56 and 58, a rear face 60 and a bottom face 62. The curvature and geometry of the faces of the insert 20, and the shape and configuration of the insert 20 more generally, are predefined such that, after installation in a chamber of the impeller 10, the insert 20 occupies a predefined volume. In the illustrated embodiment, the side faces 56, 58 and rear face 60 are configured to form a surface geometry that is complementary to an end of a chamber 16 of the impeller 10 to avoid formation of substantial cavities following installation of the insert 20 between the insert 20 and the corresponding end and sidewalls of the chamber. Thus, more generally, the insert 20 is configured to at least partially mate with a portion of the chamber in which the insert is installed.

[0054] The rear of the insert body 52 includes an attachment region for attaching the insert 20 to the impeller 10. In the illustrated embodiment, the attachment region comprises a recess or opening 64 that is shaped complementary to the attachment portion 38 such that the attachment portion 38 substantially occupies the recess 64 following installation of the insert 20. Thus, more generally, the recess is configured to at least partially mate with the attachment portion 38.

[0055] The recess 64 is configured and positioned in the insert body 52 such that it is near or at the center of gravity of the insert 20 to permit a single point of attachment. The attachment portion 38 is tapered, with the recess 64 having a complementary taper, to aid inensuring a secure fit once the insert is fully installed. This may also aid in reducing or minimizing the chance of vibrations of the insert 20 during operation.

[0056] In the illustrated embodiment, the front face 54 of the insert 20 is concave. Moreover, the insert 20 is sized so that the top face 55 and bottom face 62 are generally flush with the radially outward and inward ends of the walls between the chambers 16, respectively.

[0057] The insert body 52 includes a through bore 66 for receiving the shaft of the fastener 50. The through bore 66 extends from a front of the insert body 52 to the recess 64. Thus, access to the fastener 50 is provided from within the impeller chamber. This may improve the ease with which to replace or install the insert 20.

[0058] The through bore 66 is aligned with the bore 48 in the attachment portion 38 for installing the insert 20. In the illustrated embodiment, a conical depression 68 in the insert body 52 receives the conical head of the bolt 50 for secure and flush attachment. The through bore 66 may be configured to pass through or near the center of gravity of the insert body 52.

[0059] The shape and geometry of the insert 20 is predefined, at least in part, to be complementary to the existing geometry of the chamber into which the insert is installed and / or, at least in part, to occupy a desired volume within the chamber to affect the impeller’s volumetric capacity. It is understood that the shape, geometry and configuration of the insert in the illustrated embodiment is exemplary only and other shapes, geometries and configurations are possible. For example, the location or number of attachment points or means for attaching the insert 20 may differ. There may be multiple recesses or through bores for attachment. The manner in which the insert is attached may differ. The sizing and curvature of one or more faces of the insert may differ. Generally, one or more dimensions, aspects, or geometry of the insert may differ from the illustrated embodiments without departing from the scope of the present disclosure. If the geometry of the impeller chamber differs then the complementary geometry of the insert will differ as well.

[0060] In some embodiments, a fastener with socket cap or head protruding from the attachment portion may be used. This may allow for removal of the conical depression within the insert, increasing a thickness of the insert and the material used. Such a fastener may also allow for use of washers or other elements for balancing purposes, such as lock nuts.

[0061] As best seen in Fig. 8, the insert 20 defines a specific rake angle. The rake angle may be defined by the front face 54. Altering the rake angle may allow varying of the CR withinthe chamber 16. A flatter or negative rake angle decreases the CR. This achieves a lower discharge pressure and less absorbed power is required. A higher rake angle increases the CR. This achieves a higher discharge pressure and more absorbed power is required. The profile and geometry of the front face may differ. It may be curved to mimic the end wall of the chamber, elliptical, parabolic, a straight-line flat surface or another shape as desired to obtain and meet predefined CR requirements.

[0062] Referring to Figs. 9 to 11, a further embodiment of the insert will be described. Like features are given like reference numerals as in the embodiment described above. The embodiment shown in Figs. 9 to 11 may be considered a variable volume insert (VVI) 70. The insert 70 includes an internal void or volume 72, which in turn includes a pressurized bladder 74. Unless otherwise indicated, the insert 70 comprises the same or equivalent features as the insert 20. The bladder 74 may be configured as a hollow fitted shape and pressurized with a flexible cover material on the gas side such as Viton™ or Nitrile.

[0063] The bladder 74 may be pressurized with a compressible fluid, such as a gas. One or more openings or ports 76 in the front face 52 of the insert 70 allow for communication between the bladder 74 and the pressure within the chamber 16. This bladder wetted area portion, i.e. the portion of the bladder 74 exposed to the process gas pressure within the chamber, is in operation between the ring fluid and the inlet cone surface of the LRC.

[0064] In the case of a spike in pressure within the chambers 16 and 18, the bladder 74 may deform or be compressed, absorbing the spike in pressure and aiding in preventing damage to other portions of the impeller 10. Upon reduction in the pressure within the chambers 16 and 18, the bladder 74 may return to an original state allowing it to re-absorb a later spike in pressure.

[0065] As shown in Fig. 10, for complete protection of the impeller 10, variable volume inserts 70 may be installed in all chambers 16 and 18. As with the embodiment of fixed volume inserts described above, the illustrated embodiment in Fig. 10 is exemplary only and inserts 70 may be installed at various locations within the chambers 16, 18. Moreover, attachment means, such as attachment portions 38, would be provided in every chamber, on any end wall 30, 32 and / or 33 as needed, where an insert 70 is to be installed.

[0066] In other embodiments, attachment portions may be provided on other walls of the chambers, such as one or more of the side walls instead of or in addition to any of the end walls.

[0067] The extra volume available from the bladder movement may prevent overstressing of the second weakest areas of the impeller, i.e., blade ends / edges, in most cases. When a slugging scenario occurs (i.e. chambers filled with incompressible seal fluid such as water, naptha, chlorine, etc.), the bladder begins to compress when pressure exceeds the internal set pressure, which may be set at a desired percentage above operating pressure, thus providing the extra room required for the excess fluid to occupy.

[0068] The ports 76 may be configured to allow for a desired dampening of the bladder 74 in response to a pressure spike. For example, the location, number and / or sizing of the ports may be configured as desired and may differ from the ports in the illustrated embodiment.

[0069] While the illustrated embodiment of Figs. 9 to 11 shows an internal bladder, other embodiments are possible. Instead of a bladder, the insert may be configured to provide a variable volume using a spring-loaded piston, or a floating piston with compressed gas acting as the spring within the closed chamber side. In such embodiments, communication port or ports between the piston and the pressure within the impeller may be located next to the piston head.

[0070] One such possible embodiment is schematically illustrated in Fig. 12, where an opening 78 on the bottom of an insert 79 allows communication with a piston head 80 located within a sleeve 82. A spring 84, shown compressed, is positioned within the sleeve 82 and biases the piston head 80, returning it to a starting position after the overpressure spike subsides when the chamber rotates over a discharge port of the cone. The piston head 80 may have an oblong shape as shown, or a different shape. One or more sliding seals 83 may be provided to seal the gap between the piston head and the sleeve 82.

[0071] The insert 79 does not show an attachment means for attachment to the impeller chamber. However, as described herein, a variety of attachment means may be used to attach the inserts to the impeller chamber walls.

[0072] More generally, variable volume inserts according to the present disclosure may include a movable member, which is movable or deformable in response to a pressure spikewithin the impeller chamber. The member may be biased so that movement or deformation only occurs at a predefined overpressure as compared to the normal operating pressure range and / or such that the member is returned substantially to a starting position following dissipation or modulation of the over spike in pressure.

[0073] Fixed volume or variable volume inserts as described herein may be mounted in one or both halves of the impeller (i.e. chambers 16 and 18 in the illustrated embodiment) (single stage) or in both stages of a two-stage impeller. To ensure overpressure protection, variable volume inserts would be required in all chambers that receive fluid (e.g. chambers 16 and 18 in the illustrated embodiment). However, in the case of variable volume inserts, installing the inserts in only one half of the single stage impeller (e.g. only in chambers 16 or 18 in the illustrated embodiment) could still allow for overpressure protection in both halves if pressure communication between the two halves were provided.

[0074] Variable volume inserts may aid in avoiding costly impeller damage by absorbing the hydraulic impact of pressurized fluid inside the impeller. Variable volume insert geometry may allow a user to achieve 100% slug capacity of entire chambers without sacrificing capacity as compared to OEM capacity. This is compared to known LRCs currently in the market that typically allow up to a maximum increase of 15% in the liquid ring fluid flow before catastrophic failure. Variable volume inserts according to the present disclosure may allow LRVPs or LRCs to operate from anywhere between 0% to 100% gas fraction, thus effectively allowing the LRVPs or LRCs to operate as a Multi-Phase LRVP or LRC. This would otherwise require a much higher capital cost expenditure than a LRC or LRVP machine without sacrificing inlet gas volumetric capacity.

[0075] The inserts may be mounted anywhere within each individual impeller chamber limits, radially from ends 24 to 26, and axially between end walls 30, 32, or 33.

[0076] Referring to Figs. 13 and 14, further embodiments of an impeller and inserts according the present disclosure will be described. Like elements will be given like numerals as in other embodiments. An impeller 86 is shown having attachment portions 38 provided on each end wall of each chamber. Such an embodiment may also permit installation of an insert installed primarily axially so that the insert extends axially within a respective chamber from anattachment portion on one end wall of the chamber to an attachment portion on the other end wall of the chamber. In some embodiments, the attachment portions within a chamber are not identical and may be configured differently from each other.

[0077] An insert 88 is installed within a chamber 16 of the impeller 86. The insert 88 extends axially within the chamber 16 and is secured to a respective attachment portion 38 on either end wall of the chamber 16. In some embodiments, the insert 88 may be positioned such that substantially the entirety of the insert would be within the liquid sealing ring during operation of the compressor or pump. Moreover, the insert 88 sized and dimensioned so that gaps 90 and 92 are provided on either side of the insert 88 between the insert 88 and the respective sidewalls of the chamber 16. The gaps 90 and 92 permit the liquid sealing fluid to bypass the insert as the impeller 86 rotates. Although a single installed insert 88 is shown for the sake of clarity, it is understood that an insert 88 may be installed in all of the chambers 16 and 18 of the impeller 86. There may be only one gap or only a partial gap or gaps between the insert and the walls of the chamber.

[0078] With reference to Figs. 15 to 17, the insert 88 is configured as a VVI, with a generally cylindrical body 94 extending between an attachment region, i.e. mount 96, on one end thereof to an attachment region, i.e. mount 98, on another end thereof. The mounts 96 and 98 are each configured to mate with and attach to a respective attachment portion 38. The mounts 96 and 98 include recesses 100 and 102, respectively, sized to receive the attachment portion 38. In some embodiments, the recesses 100 and 102 may be sized and dimensioned to mate with a portion or entirety of the attachment portion 38. Through holes 104 and 106 are provided in mounts 96 and 98, respectively, to allow for a fastener to extend therethrough and connect to the attachment portion 38.

[0079] The mount 96 extends from an end surface 108 of the body 94. A port 110 is provided within the end surface 108. The port 110 allows for fluid communication with an interior 112 of the body 94. The port 110 opens into the recess 100.

[0080] The interior 112 of the body 94 is generally cylindrical and provides a space in which liquid, such as the liquid of the liquid sealing ring, may enter in the case of over pressure.

[0081] A piston 114 is positioned within the interior 112 and is slidable along a length of the interior 112. Two o-rings are provided for sealing engagement between the piston 114 and an inner surface of the interior 112. The piston 114 has an internal recess 116 on a side of the piston 114 facing away from the port 110. The recess 116 is open to the interior 112.

[0082] In normal operating conditions, the interior 112 may be primed with a compressible gas. For example, the gas might be supplied via a valve 118 communicating through a channel 120 into the interior 112.

[0083] As best seen in Fig. 17, a gap 122 is provided between the port 110 and the attachment portion 38. Liquid may access the port 110 via the gap 122. The gap may be in part provided due to the angling of the front surface 40 of the attachment portion 38, which extends away from the port 110 at an angle.

[0084] As discussed herein, overpressure within a chamber may occur when a non- compressible liquid enters a chamber as part of the operations of the machine. This may result in a pressure within the chamber being greater than the predefined priming pressure in the interior 112 of the body 94. In the case of overpressure, liquid of the sealing ring and / or liquid from the slug may enter through the port 110, act on the piston 114 and compress the gas within the interior 112. The interior 112 may be dimensioned such that complete depression of the piston 114 allows for part or all of the volume of the chamber to be received within the interior 112. The recess 116 allows for additional room for the compressible gas to be stored during compression thereof. As the impeller chamber moves over the discharge outlet, e.g. the discharge outlet of the cone, the pressure of the compressed gas begins to exceed the liquid pressure depressing the piston 114, forcing the piston 114 to return to its starting position, expelling the liquid through the port 110.

[0085] According to the present disclosure, a machine with embodiments of a system including the VVIs installed within each chamber of the impeller may be able to function as a Multi -Phase LRC or LRVP.

[0086] Fine tuning or customization of the insert 88, and thus customization of the operating parameters of the machine, are possible. Parameters that could be controlled, for example to address specific machine pulsation or frequency problems, include: the backpressure, i.e. priming pressure, within the interior 112; which compressible fluid or mixture of fluids is used within the interior 112; the size, location, number and / or configuration of the orifices permitting liquid to enter the interior 112 and depress the piston 114, for example the port 110; the diameter, length, and / or volume of the piston 114; and / or any other applicable physical constraints or parameters.

[0087] The size of recess 116 may be adjusted to tune or control (i.e. reduce or increase) the final stroke pressure of the piston 114.

[0088] The priming pressure set within embodiments of the VVI that are within the present disclosure may be adjusted to be below max operating pressure to a predefined percentage about operating pressure. Setting the priming pressure to below operating pressure may allow an LRC to run smoother in some cases, with the VVI acting as a pulsation dampener.

[0089] While certain embodiments of the attachment portions and structures for attaching the inserts to the impeller have been described, other embodiments are possible. Integrated clips, other forms of fasteners, and other attachment methods are within the scope of the present disclosure.

[0090] Another possible benefit of an impeller with attachment portions as described and disclosed herein is that the attachment portions may provide dynamic balancing points to assist in balancing of the impeller. Weight may be removed or added at each blade pass for relatively quick and precise dynamic balancing without a need to remove the impeller from the balancing mandrel. This may save time and cost by avoiding subtractive setup and machining, sometimes required more than once due to the iterative process required between machining and balance tests. Balancing of the impeller may be adjustable by adjusting one or more of: the length and / or weight (i.e. material) of the bolt or fastener inserted into the attachment portion; adding or removing weight washers using the provided threads within the bore of the attachment portion; and / or adding set screws at the bottom of the tapped hole within the attachment portion. Other methods of balancing using the attachment portions may also be possible and are within the scope of the present disclosure.

[0091] While embodiments herein have been described in terms of inserts for impellers for compressors or pumps. Principles of the present disclosure may be applicable to other types of rotors, such as turbines or compressors in other machines.

[0092] Methods are also within the scope of the present disclosure.

[0093] In some embodiments, there is provided a method for adjusting the volumetric capacity of an impeller, the impeller having a plurality of chambers defining vanes of the impeller. The includes attaching one or more inserts at least partially within one or more of the plurality of chambers. Each of the one or more inserts occupies a predefined volume within the respective chamber.

[0094] In some embodiments, at least one of the one or more inserts is configured such that the volume that the insert occupies is variable.

[0095] In some embodiments, attaching the one or more inserts comprises attaching each insert to one or more respective attachment portions within the chamber.

[0096] In some embodiments, attaching the one or more inserts comprises attaching each insert to two attachment portions at axially opposite ends of the chamber.

[0097] In some embodiments, attaching the one or more inserts comprises positioning at least one of the one or more inserts within a region of the impeller chamber that is intended to be within a liquid sealing ring when the impeller is operated in a liquid ring compressor or liquid ring vacuum pump.

[0098] Numerous specific details have been set forth in order to provide a more thorough understanding of the inventive concepts. However, it will be apparent to one of ordinary skill in the art that the inventive concepts within the instant disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the instant disclosure.

[0099] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a nonexclusive inclusion. For example, a composition, a process, method, article, or apparatus that comprises a list ofelements is not necessarily limited to only those elements but may include other elements not expressly listed or inherently present therein.

[0100] As used herein the terms "approximately," "about," "substantially" and variations thereof are intended to include not only the exact value qualified by the term, but to also include some slight deviations therefrom, such as deviations caused by measuring error, manufacturing tolerances, wear and tear on components or structures, stress exerted on structures, and combinations thereof, for example.

[0101] Use of the "a" or "an" are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the inventive concepts. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0102] Any reference to "one embodiment" or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.Moreover, it will be understood that features of one embodiment may be combined with features of other embodiments, even if not expressly recited or described as a combination.

Claims

CLAIMS:

1. A system comprising: an impeller having a plurality of chambers defining vanes of the impeller, wherein one or more of the plurality of chambers each have at least one attachment portion, and one or more inserts for attaching to one or more of the attachment portions.

2. The system of claim 1, wherein the respective attachment portions are each configured as a mount extending from a wall of the respective chamber.

3. The system of claim 1, wherein the respective attachment portions each include a single bore for receiving a corresponding fastener.

4. The system of claim 1, wherein each of the one or more inserts has a single bore for receiving a fastener and attaching the insert to a corresponding attachment portion.

5. The system of claim 4, wherein the bore is aligned with a center of gravity of the insert.

6. The system of claim 1, wherein the total volume occupied by the one or more inserts is predefined to achieve a desired compression ratio.

7. The system of claim 1, wherein each insert is configured to at least partially mate with a portion of the respective chamber in which the insert is installed.

8. The system of claim 1, wherein one or more of the one or more inserts incorporate a movable member, wherein the movable member is configured to absorb an increase in pressure within the chamber above a predefined threshold.

9. The system of claim 8, wherein one or more openings is provided in the insert to allow for fluid communication between the movable member and the respective chamber.

10. The system of claim 8, wherein the movable member is configured as a piston.

11. The system of claim 8, wherein the movable member is configured as a bladder within a void of the insert.

12. The system of claim 1, wherein each of the one or more inserts includes a recess shaped to at least partially mate with the respective attachment portion.

13. The system of claim 1, wherein the total volume occupied by the one or more inserts is predefined to achieve a desired volumetric capacity.

14. The system of claim 1, wherein each insert is attached to two attachment portions.

15. The system of claim 1, wherein each insert extends axially across a respective one of the plurality of chambers.

16. A liquid ring compressor or a liquid ring vacuum pump comprising the system of claim 1.

17. An insert for an impeller, the insert comprising an insert body configured to occupy a predefined volume and having an attachment region for attaching the insert within a chamber of the impeller.

18. The insert of claim 17, wherein the attachment region comprises a recess.

19. The insert of claim 18, wherein the recess is sized and shaped to mate with a complementary attachment portion within the chamber.

20. The insert of claim 17, wherein the insert body comprises one or more faces, at least one of the one or more faces being shaped complementary to one or more respective walls of a chamber of the impeller.

21. The insert of claim 17, further comprising a through bore for receiving a fastener.

22. The insert of claim 21, wherein the through bore is configured to pass through, or near the center of gravity of the insert body.

23. The insert of claim 17, further comprising an internal void and one or more openings in the insert body allowing fluid communication with the void.

24. The insert of claim 23, wherein the void comprises a movable member that is configured to move when pressure in the impeller chamber exceeds a predefined threshold.

25. The insert of claim 24, wherein the movable member is configured as a piston.

26. A method for adjusting the volumetric capacity of an impeller, the impeller having a plurality of chambers defining vanes of the impeller, the method comprising: attaching one or more inserts at least partially within one or more of the plurality of chambers, each of the one or more inserts occupying a predefined volume within the respective chamber.

27. The method of claim 26, wherein at least one of the one or more inserts is configured such that the volume that the insert occupies is variable.

28. The method of claim 26, wherein attaching the one or more inserts comprises attaching each insert to one or more respective attachment portions within the chamber.

29. The method of claim 26, wherein attaching the one or more inserts comprises attaching each insert to two attachment portions at axially opposite ends of the chamber.

30. The method of claim 26, wherein attaching the one or more inserts comprises positioning at least one of the one or more inserts within a region of the impeller chamber that is intended to be within a liquid sealing ring when the impeller is operated in a liquid ring compressor or liquid ring vacuum pump.

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