Compact variable geometry diffuser mechanism

Abstract

A diffuser system for a centrifugal compressor is provided. The diffuser system includes a nozzle base plate (206) defining a diffusion gap (212), a support block (216, 246), and a drive ring (220) rotatable relative to the support block. The drive ring includes cam tracks (224, 242) and bearing assemblies (226, 234) positioned near an outer circumference of the drive ring. The diffuser system further includes drive pins (214) extending through the support block and the nozzle base plate. A first end of each drive pin includes a cam follower (218) mounted into a cam track of the drive ring. A second end of each drive pin is coupled to a diffusion ring (208). Rotation of the drive ring causes axial movement of the drive pins by moving the cam followers in the cam tracks. This causes movement of the diffusion ring to control fluid flow through the diffusion gap.

Description

[0001] This application is a divisional application of the invention patent application with an international filing date of September 21, 2018, international application number PCT / US2018 / 052254, national application number 201880075086.0, and invention title "Compact Variable Geometry Diffuser Mechanism".

[0002] Cross-references to related applications

[0003] This application claims the benefit and priority of U.S. Provisional Patent Application No. 62 / 562,682, filed September 25, 2017, the entire disclosure of which is incorporated herein by reference. Background Technology

[0004] Buildings may include heating, ventilation, and air conditioning (HVAC) systems. Summary of the Invention

[0005] One embodiment of this disclosure is a diffuser system for a centrifugal compressor. The diffuser system includes a nozzle base defining a diffusion gap, a support block, and a drive ring rotatable relative to the support block. The drive ring includes a cam track and a bearing assembly positioned near the outer circumference of the drive ring. The diffuser system further includes drive pins extending through the support block and the nozzle base. A first end of each drive pin includes a cam follower mounted to a cam track on the drive ring. A second end of each drive pin is coupled to the diffuser ring. Rotation of the drive ring causes axial movement of the drive pin by moving the cam follower in the cam track. This causes movement of the diffuser ring to control fluid flow through the diffusion gap.

[0006] The bearing assembly may include an axial bearing assembly and a radial bearing assembly. The radial bearing assembly may include a roller member that contacts the outer circumferential surface of the drive ring. The roller member can resist radial movement of the drive ring when it rotates. The drive device may include a second set of cam tracks. The axial bearing assembly may include a bearing member mounted in one of the second set of cam tracks. The bearing member can resist axial movement of the drive ring when it rotates. The second set of cam tracks may be parallel to the top and bottom surfaces of the drive ring. The other set of cam tracks may be inclined relative to the top and bottom surfaces of the drive ring. The second position of the diffuser ring can completely close the diffuser gap and prevent fluid from flowing through the diffuser gap.

[0007] Another embodiment of this disclosure is a system for a variable-capacity centrifugal compressor used to compress fluids. The system includes: a housing; an impeller rotatably mounted within the housing for compressing fluid introduced through an inlet; and a diffuser system mounted within the housing and configured to stabilize fluid flow exiting the impeller. The diffuser system includes a nozzle base defining a diffusion gap, a support block, and a drive ring rotatable relative to the support block. The drive ring includes a cam track and a bearing assembly positioned near the outer circumference of the drive ring. The diffuser system further includes drive pins extending through the support block and the nozzle base. A first end of each drive pin includes a cam follower mounted to a cam track on the drive ring. A second end of each drive pin is coupled to the diffuser ring. Rotation of the drive ring causes axial movement of the drive pins by moving the cam follower in the cam track. This causes movement of the diffuser ring to control fluid flow through the diffusion gap.

[0008] The bearing assembly may include an axial bearing assembly and a radial bearing assembly. The radial bearing assembly may include a roller member that contacts the outer circumferential surface of the drive ring. The roller member can resist radial movement of the drive ring when it rotates. The drive device may include a second set of cam tracks. The axial bearing assembly may include a bearing member mounted in one of the second set of cam tracks. The bearing member can resist axial movement of the drive ring when it rotates. The second position of the diffuser ring can completely close the diffuser gap and prevent fluid from flowing through the diffuser gap. The impeller may be a high specific speed impeller. The fluid may be a refrigerant. The refrigerant may be R1233zd.

[0009] Another embodiment of this disclosure is a diffuser system for a centrifugal compressor. The diffuser system includes: a nozzle base plate that mates with opposing inner surfaces to define a diffusion gap, a support block, and a drive ring rotatable relative to the support block. The drive ring includes a cam track. The diffuser system further includes a bearing assembly positioned on the outer circumferential surface of the drive ring and resisting movement of the drive ring in both radial and axial directions. The diffuser system further includes drive pins extending through the support block and the nozzle base plate. A first end of each drive pin includes a cam follower mounted in a cam track on the drive ring. A second end of each drive pin is coupled to the diffuser ring.

[0010] The bearing assembly may include a V-groove bearing assembly having an outer ring and an inner ring. The outer ring includes two flanges extending in a V-shape. The inner ring allows the outer ring to rotate relative to the inner ring. The drive ring may include a base and an extension orthogonally positioned relative to each other. The extension may engage the two flanges of the outer ring. Attached Figure Description

[0011] Figure 1 This is a perspective view of a cooler assembly according to some embodiments.

[0012] Figure 2 According to some embodiments Figure 1 An elevation view of the cooler assembly.

[0013] Figure 3 According to some embodiments, it is possible to Figure 1 A perspective view of the compressor and motor components used in the refrigeration unit.

[0014] Figure 4 This is a cross-sectional view of a variable geometry diffuser (VGD) used in a centrifugal compressor according to some embodiments.

[0015] Figure 5 According to some embodiments Figure 3 A perspective view of the nozzle substrate and drive ring assembly of the VGD.

[0016] Figure 6 According to some embodiments Figure 5 A perspective view of the nozzle substrate and drive ring assembly.

[0017] Figure 7 According to some embodiments Figure 5 Detailed view of the nozzle substrate and drive ring assembly.

[0018] Figure 8 This is a detailed view of a non-compact VGD design according to some embodiments.

[0019] Figure 9 This is a detailed view of a compact design VGD according to some embodiments.

[0020] Figure 10 Based on some embodiments Figure 9 A front view of the drive ring used in the compact design of VGD.

[0021] Figure 11 This is a perspective view of a V-groove cam follower bearing according to some embodiments.

[0022] Figure 12 This is a cross-sectional view of the V-groove cam follower bearing and drive ring assembly according to some embodiments. Detailed Implementation

[0023] Referring generally to the accompanying drawings, a compact variable geometry diffuser (VGD) for use with the impeller in a centrifugal compressor within a refrigeration unit is shown. Centrifugal compressors can be used in a variety of devices requiring fluid compression, such as coolers. To achieve this compression, centrifugal compressors use rotating components to convert angular momentum into an increase in static pressure within the fluid.

[0024] A centrifugal compressor may include four main components: an inlet, an impeller, a diffuser, and a collector or volute. The inlet may include a simple conduit that draws fluid (e.g., refrigerant) into the compressor and delivers it to the impeller. In some instances, the inlet may include inlet guide vanes that ensure axial flow of fluid to the impeller inlet. The impeller is a set of rotating blades that gradually increase the fluid's energy as it moves from the center of the impeller (also called the eye of the impeller) to the outer peripheral edge of the impeller (also called the end of the impeller). Downstream of the impeller in the fluid path is the diffuser mechanism, which slows the fluid and thus converts its kinetic energy into static pressure energy. After leaving the diffuser, the fluid enters the collector or volute, where its shape further converts kinetic energy into static pressure. In some embodiments, the collector or volute is integrally formed with a scroll assembly, which may house other compressor components such as the impeller and diffuser.

[0025] The diffuser mechanism can be a variable geometry diffuser (VGD) mechanism with a diffuser ring that moves between a first retracted position and a second extended position. In the first retracted position, flow through the diffuser gap is unimpeded; in the second extended position, the diffuser ring extends into the diffuser gap to alter the fluid flow through it. It is often desirable to change the amount of fluid flowing through the compressor or the pressure differential generated by the compressor. For example, when the fluid flow through the compressor decreases while maintaining the same pressure differential at the impeller, the fluid flow through the compressor may become unstable. Some fluid may stall within the compressor, and stalled fluid pockets may begin to rotate with the impeller. These stalled fluid pockets can cause problems due to the noise, vibration, and reduced efficiency they cause in the compressor, leading to a condition known as rotating stall or initial surge. If the fluid flow decreases further, the fluid flow may become even more unstable and may even cause the fluid flow to completely reverse, a condition known as surge. Surge is characterized by fluid flowing alternately forward and backward through the compressor and, in addition to noise, vibration, and reduced compressor efficiency, can lead to pressure spikes and compressor damage.

[0026] By altering the diffuser geometry at the impeller outlet, the adverse effects of rotational stall, initial surge, and surging can be minimized. When operating at low fluid flow rates, the diffuser ring of the VGD mechanism can be actuated to reduce the diffuser gap size at the impeller outlet. The reduced area prevents fluid stall and backflow through the impeller. As the fluid flow rate increases, the diffuser ring of the VGD mechanism can be actuated to increase the diffuser gap size, thus providing a larger area for additional flow. The VGD mechanism can also be adjusted in response to pressure differential changes generated by the compressor. For example, when the pressure differential increases, the diffuser ring of the VGD mechanism can be actuated to reduce the diffuser gap size, thereby preventing fluid stall and surging. Conversely, when the pressure differential increases, the diffuser ring of the VGD mechanism can be actuated to increase the diffuser gap size, thereby providing a larger area at the impeller outlet. In addition to preventing stall and surging, the VGD mechanism can also be used for capacity control, minimizing transient loads associated with compressor reversal and during compressor reversal, and minimizing start-up transients.

[0027] The impeller type chosen for a compressor can have design implications for other components, especially the VGD mechanism. For example, the typical ratio of the impeller tip diameter to the impeller bore diameter can range from 1.5 to 3.0, with 1.5 representing a higher specific speed impeller and 3.0 representing a lower specific speed impeller. In other words, when using a higher specific speed impeller in a centrifugal compressor, the impeller's center inlet is larger than its outer diameter. Low specific speed impellers primarily generate the hydraulic head through centrifugal force, while high specific speed impellers generate the hydraulic head through both centrifugal and axial forces. Because the impeller's center inlet or bore can be located near certain components of the VGD mechanism, a high specific speed impeller may encroach on space originally reserved for the VGD mechanism. Therefore, it can be useful to design the VGD mechanism to maximize the amount of space available for installing the impeller within the compressor.

[0028] Reference Figures 1 to 2 An exemplary embodiment of a cooler assembly 100 is depicted. The cooler assembly 100 is shown as including a compressor 102 driven by a motor 104, a condenser 106, and an evaporator 108. Refrigerant is circulated through the cooler assembly 100 via a vapor compression cycle. The cooler assembly 100 may also include a control panel 114 for controlling the operation of the vapor compression cycle within the cooler assembly 100.

[0029] Motor 104 is powered by a variable speed drive (VSD) 110. VSD 110 receives AC power (not shown) with a specific fixed line voltage and frequency, and supplies motor 104 with power having a variable voltage and frequency. Motor 104 can be any type of electric motor that can be powered by VSD 110. For example, motor 104 can be a high-speed induction motor. Compressor 102 is driven by motor 104 to compress refrigerant vapor received from evaporator 108 via suction line 112 and to deliver the refrigerant vapor to condenser 106 via discharge line 124. Compressor 102 can be a centrifugal compressor, screw compressor, scroll compressor, turbo compressor, or any other suitable type of compressor. In the embodiment depicted in the figures, compressor 102 is a centrifugal compressor.

[0030] Evaporator 108 includes an internal tube bundle (not shown) and supply lines 120 and return lines 122 for supplying and removing process fluid to and from the internal tube bundle. Supply lines 120 and return lines 122 may be in fluid communication with components inside an HVAC system (e.g., an air handler) via conduits circulating the process fluid. The process fluid is a cooling liquid used to cool a building and may be, but is not limited to, water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable liquid. Evaporator 108 is configured to reduce the temperature of the process fluid as it passes through the tube bundle and exchanges heat with the refrigerant. Refrigerant vapor is formed in evaporator 108 from a refrigerant liquid that is supplied to evaporator 108, exchanges heat with the process fluid, and undergoes a phase change to become refrigerant vapor.

[0031] Refrigerant vapor delivered by compressor 102 to condenser 106 transfers heat to the fluid. Due to heat transfer with the fluid, the refrigerant vapor condenses into refrigerant liquid in condenser 106. The refrigerant liquid from condenser 106 flows through an expansion device (not shown) and returns to evaporator 108 to complete the refrigerant cycle of refrigeration unit 100. Condenser 106 includes a supply line 116 and a return line 118 for circulating fluid between condenser 106 and external components of the HVAC system (e.g., a cooling tower). Fluid supplied to condenser 106 via return line 118 exchanges heat with the refrigerant in condenser 106 and is removed from condenser 106 via supply line 116 to complete the cycle. The fluid circulating through condenser 106 can be water or any other suitable liquid.

[0032] In some embodiments, the refrigerant has an operating pressure of less than 400 kPa or about 58 psi. In a further embodiment, the refrigerant is R1233zd. R1233zd is a non-flammable fluorinated gas with a lower Global Warming Potential (GWP) compared to other refrigerants used in commercial cooler components. GWP is a metric developed to compare the impact of different gases on global warming by quantifying how much energy one tonne of a gas will absorb over a given period of time, relative to one tonne of carbon dioxide emissions.

[0033] Now go to Figure 3 The figure depicts a perspective view of compressor 102 and motor 104. As shown, actuator 126 can be positioned near the outer surface of compressor 102. Actuator 126 can be any suitable type of actuator or actuation device capable of being coupled to VGD to rotate the drive ring. In some embodiments, actuator 126 is coupled to VGD using a series of links. Reference is made below. Figure 7 Including further details of the rotation of the drive ring.

[0034] Now refer to Figure 4 A cross-sectional view of a VGD 200 in a compressor 102 according to some embodiments is depicted. As shown, the compressor 102 may include a diffuser plate 202, an impeller 204, a nozzle substrate 206, and a suction plate housing 252. In some embodiments, the diffuser plate 202 is integral with a component of the compressor housing (not shown). In other embodiments, the diffuser plate 202 is detachably attached to the compressor housing by fasteners. The diffuser plate 202 is shown positioned relative to the nozzle substrate 206 and the suction plate housing 252. The nozzle substrate 206 (see below) Figures 6 to 8 (In further detail) It can be detachably connected to the suction plate housing 252 via fasteners. The suction plate housing 252 can be connected to the suction inlet line or to another component of the compressor housing to form a refrigerant inlet passage. In different embodiments, the diffuser plate 202, the nozzle substrate 206, and the suction plate housing 252 are manufactured using casting or machining processes.

[0035] The rotation of impeller 204 does work on the fluid, thereby increasing the fluid pressure. As described above, in some embodiments, impeller 204 is a high specific speed VGD. The fluid is typically refrigerant, which enters at impeller inlet 250. After passing through impeller 204, the refrigerant exits impeller 204 at a higher velocity and passes through diffuser gap 212 as it is guided to collector or volute and eventually reaches compressor outlet.

[0036] A diffuser ring 208 is assembled into a groove 210. In some embodiments, the groove 210 is machined into the surface of the nozzle substrate 206 and / or the suction plate housing 252. In other embodiments, the groove 210 is formed by the geometry of the nozzle substrate 206 and the suction plate housing 206 when the components are connected to each other. The diffuser ring 208 can move away from the groove 210 and into a diffusion gap 212 that separates the diffuser plate 202 and the nozzle substrate 206. In the fully retracted position, the diffuser ring 208 is nested in the groove 210, and the diffusion gap 212 is in a maximum flow state. In the fully extended position (e.g.) Figure 4 As depicted, the diffusion ring 208 extends substantially across the diffusion gap 212, thereby substantially closing the diffusion gap 212. The diffusion ring 208 can be moved to any position between a fully retracted position and a fully extended position. In some embodiments, the diffusion ring 208 has a generally annular shape and a rectangular cross-section, but the diffusion ring 208 may have any cross-section (e.g., L-shaped) to achieve the desired flow characteristics through the diffusion gap 212.

[0037] A diffuser ring 208 is attached (e.g., via fasteners) to a plurality of drive pins 214. Each drive pin 214 includes a first end 254 and a second end 256. In various embodiments, the first end 254 of the drive pin 214 may be bolted, welded, or brazed into the diffuser ring 208. In a further embodiment, the drive pin 214 may be securely connected to the diffuser ring 208 via a threaded portion on the first end 254 of the drive pin 214, which screws into a threaded hole on the annular diffuser ring 208. Each drive pin 214 includes a hole on its second end 256 for engaging the drive pin 214 to a cam follower 218. Reference is made below. Figure 8 Further details include the cam follower 218.

[0038] Turn now Figures 5 to 7 It describes a method according to some embodiments. Figure 4 Perspective and front views of the nozzle substrate 206 and drive ring 220 of the VGD 200 are shown. As shown, the drive ring 220 is generally annular and includes a top surface 228, an inner circumferential surface 230, an outer circumferential surface 238, and a bottom surface 240. When installed in the compressor 102, the VGD 200 can be oriented such that the top surface 228 of the drive ring 220 is located near the suction inlet of the compressor 102, and the bottom surface 240 of the drive ring 220 is located near the diffusion gap 212, as referenced above. Figure 4The drive ring 220 is assembled onto support blocks 216 and 246, which extend below the drive ring 220. In some embodiments, support blocks 216 and 246 are integrally formed with the nozzle substrate 206 (e.g., using casting or machining processes). In other embodiments, support blocks 216 and 246 are manufactured as separate components and then assembled to the nozzle substrate 206 (e.g., using fasteners such as bolts or pins).

[0039] Using the drive pin 214, the support block 216 facilitates the connection between the diffuser ring 208 and the drive ring 220, while the support block 246 can simultaneously accommodate the axial bearing assembly 232 and the radial bearing assembly 234. For example... Figure 6 As specifically shown, support blocks 216 and 246 can alternate around the nozzle substrate 206, such that each support block 216 includes support block 246 on either side, and vice versa. Figure 6 In the embodiment depicted, the VGD 200 includes five support blocks 216 and five support blocks 246, and therefore the VGD 200 includes five drive pins 214, five axial bearing assemblies 232, and five radial bearing assemblies 234. Since the support blocks 216 and 246 can be evenly distributed around the nozzle substrate 206, each support block 216 and 246 can be positioned at approximately 72° intervals (e.g., ±10%). In other embodiments, the VGD may include different numbers of support blocks 216 and 246, and correspondingly different numbers of drive pins 214, axial bearing assemblies 232, and radial bearing assemblies 234.

[0040] Drive pin 214 is assembled into support block 216 and extends downward through nozzle substrate 206. Because drive pin 214 extends through a hole in nozzle substrate 206 and because nozzle substrate 206 is attached to suction plate housing 252, drive pin 214 prevents rotational movement of diffuser ring 208. Drive pin 214 is coupled to cam followers 218, which are assembled into cam tracks 224. For example, cam followers 218 can be assembled through holes in drive pin 214 and secured to drive pin 214 with nuts. In other embodiments, cam followers 218 can be secured to drive pin 214 using another attachment method (e.g., locking pin device), provided that cam followers 218 are free to rotate relative to drive pin 214. Cam tracks 224 are grooves formed into the outer circumferential surface 238 of drive ring 220. Each cam track 224 can be manufactured with a preselected depth and preselected width to receive cam followers 218 and can correspond to and engage with support block 216. Therefore, in Figure 6 In the depicted embodiment, the drive ring 220 will have five cam tracks 224 corresponding to the five support blocks 216.

[0041] For specific references Figure 7 The image depicts a perspective view of an axial bearing assembly 226 and a radial bearing assembly 234. The axial bearing assembly 226 includes a support structure 258 for the axial bearing 232 and an attachment device (not shown) for securing the support structure 258 to a support block 246. The axial bearing 232 can be secured to the support structure 258 using any suitable means (e.g., a nut). The axial bearing 232 is assembled into an axial cam track 242, as shown below. Figure 10 Further detailed description. The axial bearing 232 resists axial movement of the drive ring 220 as the drive ring 220 rotates. In some embodiments, the axial bearing 232 also allows for minor adjustments to the axial position of the drive ring 220. Any other suitable axial bearing assembly that can resist axial movement of the drive ring 220 as it rotates can be used.

[0042] Figure 7 A radial bearing assembly 234 mounted on a support block 246 is also shown. The radial bearing assembly 234 includes a roller 236. The roller 236 can be secured to the support block 246 using a partially threaded shaft 260, but the roller 236 can be allowed to rotate freely relative to the partially threaded shaft 260. The radial bearing assembly 234 resists radial movement of the drive ring 220 as the drive ring rotates. Any other suitable radial bearing assembly that can resist radial movement of the drive ring 220 as it rotates can be used.

[0043] The VGD 200 can be operated as follows: When a stall or surge condition is detected (e.g., by a sensor) within the compressor 102, an actuator (e.g., actuator 126) causes the drive ring 220 to rotate. The drive ring 220 is restricted to rotational movement within the plane in which it lies above the support blocks 216 and 246. As the drive ring 220 rotates, each cam follower 218 moves along the track toward the bottom surface 240 of the drive ring 220 from a first position in the cam track groove of the cam track 224 near the top surface 228 of the drive ring 220. As the drive ring 220 and the cam track 224 rotate, the cam follower 218 is forced downward along the track 224. As the follower 218 moves downward, the drive pin 214 moves into the support block 216. Since the diffuser ring 208 is attached to the opposite end of the drive pin 214 (i.e., the first end 254 of the drive pin 214) on the opposite side of the nozzle substrate 206, movement of the drive pin 214 into the support block 216 causes the first end 254 of the drive pin 214 to move away from the groove 210, thereby moving the diffuser ring 208 into the diffuser gap 212. Depending on the control system, an actuator or other actuation device can stop the rotation of the drive ring 220 at any position between the fully retracted and fully extended positions of the actuator. This, in turn, causes the diffuser ring 208 to stop at any position between the fully extended and fully retracted positions within the groove 210.

[0044] Now for reference Figure 8 Detailed views of a non-compact implementation of the VGD 200 are depicted. For example, Figure 8 This implementation can be used with low specific speed impellers, where the ratio of the diameter of the widest part of the impeller (i.e., the blade tip) to the diameter of the impeller's wheel eye is relatively large (e.g., about 3.0). As shown, the drive ring 220 is assembled to the support block 216 via a radial bearing assembly 234 and an axial bearing assembly 226. The radial bearing assembly 234 with roller 236 and the axial bearing assembly 226 with axial bearing 232 are both mounted on the inner circumferential surface 230 of the drive ring 220. Conversely, the drive pin 214 is mounted on the outer circumferential surface 238 of the drive ring 220.

[0045] Now for reference Figure 9 This depicts a detailed view of a compact implementation of the VGD 200. (Compared to...) Figure 8 The implementation method described herein is the opposite. Figure 9 (as well as Figures 4 to 7 The VGD depicted in [reference 1] can be used with high specific speed impellers, where the diameter of the widest part of the impeller is relatively small relative to the impeller's wheel bore diameter (e.g., about 1.5). As shown, the drive ring 220 is assembled to the support block 216 via a radial bearing assembly 234 and an axial bearing assembly 226. [Referring to the above reference...] Figure 8 The described structures are different. Figure 9 In the configuration, each of the drive pin 214, the radial bearing assembly 234 with rollers 236, and the axial bearing assembly 226 with axial bearings 232 is mounted on the outer circumferential surface 238 of the drive ring 220. As described above, Figure 9 The configuration depicted is best suited for VGDs where the size of the impeller eye limits the available space within the area surrounded by the inner circumferential surface 230. The space utilized by the VGD 200 is optimized by repositioning the radial bearing assembly 234 and the axial bearing assembly 226 to the outer circumferential surface 238 of the drive ring 220.

[0046] Now go to Figure 10 The image depicts a front view of a drive ring 220 according to some embodiments. The drive ring 220 is shown as including a plurality of cam tracks 224 and 242 distributed on an outer circumferential surface 238 of the drive ring 220, thus allowing it to be coupled with... Figures 4 to 7 and Figure 9 The compact VGD design depicted herein is used in conjunction with this. The cam track 224 is shown extending from the bottom surface 240 of the drive ring 220 toward the top surface 228 of the drive ring 220, at an angle between these surfaces and preferably extending substantially in a straight line. At the end of the cam track 224 near the bottom surface 240 of the drive ring 220, the track includes a portion 262 extending to the bottom surface 240 to provide passage for assembling the cam follower 218 into the cam track 224. The distance by which the cam track 224 extends parallel to the axis of the drive ring 220 substantially corresponds to the width of the diffuser gap 212. The angle of the cam track 224 can be any pre-selected angle. As the angle becomes shallower, the control of the drive ring 220 and, correspondingly, the diffuser ring 208 becomes more precise.

[0047] The axial cam track 242 is shown extending in a direction substantially parallel to the top surface 228 and bottom surface 240 of the drive ring 220. Each cam track 242 can be manufactured with a preselected depth and preselected width to receive the axial bearing 232. Furthermore, each cam track 242 can terminate in a circular cut 244 at either end. The circular cut 244 facilitates the removal of tools used to cut the axial cam track 242.

[0048] As shown in the figure, the axial cam track 242 can be located or "nested" within the axial space occupied by the cam track 224. This configuration reduces the overall axial dimensions of the drive ring 220 and VGD 200. Furthermore, the dimensions (e.g., width, depth) of the cam tracks 224 and 242 can optimize the manufacturing process of the drive ring 220. For example, the cam tracks 224 and 242 can be formed using a milling process, and the same milling tool can be used to cut both cam tracks 224 and 242 simultaneously. Using the same milling tool for both cam tracks 224 and 242 allows for higher precision in the finished part because less machine tool setup is required.

[0049] Now refer to Figure 11 The figure depicts a perspective view of a V-groove cam follower bearing 300 according to some embodiments. In various embodiments, the V-groove cam follower bearing 300 can be used in place of both the axial bearing assembly 226 and the radial bearing assembly 234 because the geometry of the V-groove bearing 300 can simultaneously restrict movement in both the radial and axial directions. As shown, the bearing 300 includes an outer ring 302 and an inner ring 304. The outer ring 302 may include two symmetrical flanges extending in a V-shaped cross-section. The inner ring 304 may include any type of suitable rolling element (e.g., ball, roller, cone, needle) such that the outer ring 302 is allowed to rotate freely relative to the inner ring 304.

[0050] Figure 12 A cross-sectional view of a V-groove cam follower bearing and drive ring assembly 400 is depicted. In various embodiments, assembly 400 is a sub-assembly of a VGD, which includes the components referenced above. Figures 4 to 11 The VGD 200 is described. As shown, component 400 includes a V-groove cam follower bearing 300 and a drive ring 404 adapted to operate with the V-groove bearing. The drive ring 404 may have a substantially annular shape with an L-shaped cross-section formed by an extension 406 and a base 408. The extension 406 and the base 408 may be positioned orthogonally relative to each other. The base 408 may include a cam track 412 of any size required to receive a cam follower (e.g., cam follower 218, not shown).

[0051] The bearing 300 can be secured to another component of the VGD (e.g., a support block) using fasteners 410 (e.g., bolts). Fasteners 410 can be used to position the bearing 300 such that the two flanges of the outer ring 302 contact the extension 406 of the drive ring 404. In this way, the bearing 300 can be used to simultaneously restrict movement of the drive ring 404 in both the axial and radial directions.

[0052] The construction and arrangement of the systems and methods illustrated in the various exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, many modifications are possible (e.g., variations in the size, dimensions, structure, shape and proportions of various elements, parameter values, installation arrangements, use of materials, color, orientation, etc.). For example, the positions of elements may be reversed or otherwise varied, and the nature or number or position of discrete elements may be altered or changed. Therefore, all such modifications are intended to be included within the scope of this disclosure. The order or sequence of any process or method steps may be changed or reordered according to alternative embodiments. Other substitutions, modifications, alterations, and omissions may be made in terms of the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of this disclosure.

Claims

1. A diffuser system for a compressor, the diffuser system comprising: a nozzle base plate configured to at least partially define a diffuser gap; a drive ring including a plurality of first cam tracks and a plurality of second cam tracks formed on an outer circumferential surface of the drive ring; a diffuser ring coupled to the drive ring via a plurality of drive pins extending through the nozzle base plate, wherein a first end of each drive pin includes a cam follower positioned within a corresponding first cam track of the plurality of first cam tracks, and a second end of each drive pin is coupled to the diffuser ring; and at least one bearing assembly disposed about the outer circumferential surface of the drive ring.

2. The diffuser system of claim 1, comprising a plurality of support blocks extending from a side of the nozzle base plate opposite the diffuser gap, wherein each drive pin of the plurality of drive pins is configured to extend through a respective support block of the plurality of support blocks.

3. The diffuser system of claim 2, wherein the drive ring is rotatable relative to the plurality of support blocks between a first position and a second position, and wherein rotation of the drive ring causes an adjustment of a diffuser ring position of the diffuser ring relative to the diffuser gap.

4. The diffuser system of claim 3, wherein the second position of the drive ring corresponds to a fully closed position of the diffuser ring within the diffuser gap, and the diffuser ring is configured to block fluid flow through the diffuser gap in the fully closed position.

5. The diffuser system of claim 1, wherein the drive ring includes a plurality of bearing assemblies disposed about the outer circumferential surface of the drive ring, and the plurality of bearing assemblies includes the at least one bearing assembly.

6. The diffuser system of claim 5, wherein the plurality of bearing assemblies includes an axial bearing assembly and a radial bearing assembly.

7. The diffuser system of claim 6, wherein the radial bearing assembly includes a roller member in contact with the outer circumferential surface of the drive ring, and the roller member is configured to resist radial movement of the drive ring.

8. The diffuser system of claim 6, wherein the axial bearing assembly includes a bearing member extending within a respective second cam track of the plurality of second cam tracks of the drive ring, and the bearing member is configured to resist axial movement of the drive ring.

9. The diffuser system of claim 1, wherein each first cam track of the plurality of first cam tracks is angled relative to a top surface and a bottom surface of the drive ring, and each second cam track of the plurality of second cam tracks is substantially parallel to the top surface and the bottom surface of the drive ring.

10. The diffuser system of claim 1, wherein a second axial dimension of each second cam track of the plurality of second cam tracks extends within a respective first axial dimension of each first cam track of the plurality of first cam tracks between a top surface and a bottom surface of the drive ring. ​ 11. A compressor, comprising: a housing; an impeller rotatably mounted in the housing and configured to compress a fluid received by the compressor; and a diffuser system mounted in the housing and configured to regulate a flow of the fluid through the compressor, wherein the diffuser system comprises: a nozzle base plate configured to at least partially define a diffusion gap; a drive ring comprising a first plurality of cam tracks and a second plurality of cam tracks formed on an outer circumferential surface of the drive ring; a diffusion ring coupled to the drive ring via a plurality of drive pins extending through the nozzle base plate, wherein a first end of each drive pin comprises a cam follower positioned within a corresponding first cam track of the first plurality of cam tracks and a second end of each drive pin is coupled to the diffusion ring; and at least one bearing assembly disposed about the outer circumferential surface of the drive ring.

12. The compressor of claim 11, wherein the diffuser system comprises a plurality of support blocks extending from a side of the nozzle base plate opposite the diffusion gap, wherein the drive ring is configured to rotate relative to the plurality of support blocks, and wherein each of the plurality of drive pins extends into a corresponding support block of the plurality of support blocks and is configured to translate relative to the corresponding support block during rotation of the drive ring.

13. The compressor of claim 12, wherein the nozzle base plate comprises a surface opposite the side of the nozzle base plate and adjacent to the diffusion gap, the surface comprising a groove formed on the surface and configured to at least partially receive the diffusion ring, and the plurality of drive pins are configured to regulate a position of the diffusion ring relative to the groove and relative to the diffusion gap during rotation of the drive ring. the plurality of support blocks are a first plurality of support blocks, the diffuser system comprises a second plurality of support blocks extending from the side of the nozzle base plate opposite the diffusion gap, and each of the second plurality of support blocks is configured to support:

14. The compressor of claim 12 wherein, an axial bearing assembly disposed about the outer circumferential surface of the drive ring and configured to resist axial movement of the drive ring; a radial bearing assembly disposed about the outer circumferential surface of the drive ring and configured to resist radial movement of the drive ring; or both.

15. The compressor of claim 11, wherein the compressor is a centrifugal compressor and the impeller is a high specific speed impeller.

16. A variable geometry diffuser, comprising: a diffusion ring configured to extend into a diffusion gap of a compressor to regulate a flow of a fluid through the compressor; a plurality of drive pins secured to the diffusion ring; a drive ring comprising a plurality of cam tracks formed on an outer circumferential surface of the drive ring; and ​ ​ a plurality of bearing assemblies disposed only around the outer circumferential surface of the drive ring, wherein each of the plurality of drive pins is configured to interface with a corresponding cam track of the plurality of cam tracks, each drive pin is configured to translate within the corresponding cam track of the plurality of cam tracks during rotation of the drive ring, and the plurality of drive pins are configured to adjust a position of the diffuser ring relative to the diffusion gap during rotation of the drive ring.

17. The variable geometry diffuser of claim 16, wherein the plurality of bearing assemblies includes an axial bearing assembly and a radial bearing assembly.

18. The variable geometry diffuser of claim 17, comprising a nozzle baseplate including support blocks, wherein the nozzle baseplate is configured to at least partially define the diffusion gap, and the axial bearing assembly and the radial bearing assembly are secured to the support blocks.

19. The variable geometry diffuser of claim 18, wherein the nozzle baseplate includes a plurality of second support blocks, each of the plurality of drive pins extends into a corresponding second support block of the plurality of second support blocks and through the nozzle baseplate to couple to the diffuser ring, and each of the plurality of drive pins is configured to translate within the corresponding second support block during rotation of the drive ring.

20. The variable geometry diffuser of claim 18, wherein, the plurality of cam tracks are a plurality of first cam tracks, the drive ring includes a second cam track formed in the outer circumferential surface, the axial bearing assembly includes an axial bearing configured to interface with the second cam track, and each of the plurality of first cam tracks is angled relative to the second cam track.

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