Scroll expander assembly and organic Rankine cycle system
By incorporating a lubricant supply mechanism into the vortex expander, lubricant is directly supplied to the fluid chamber, solving the problems of insufficient lubrication and the impact of air intake, achieving effective lubrication and efficiency improvement, and enhancing the system's reliability and overall performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-03
- Publication Date
- 2026-04-10
AI Technical Summary
In organic Rankine cycle systems, insufficient lubrication of the scroll expander and the shared intake pipeline between the lubricant and the working fluid can affect the intake volume, impacting the normal operation and efficiency of the system.
By setting up a lubricant supply mechanism in the scroll expander, the lubricant is directly supplied to the fluid chamber of the scroll expander, independent of the air intake pipeline. The lubricant is pressurized by an oil pump and driven by the scroll expander, which can effectively lubricate the scroll plate and improve the system efficiency.
It achieves effective lubrication of the vortex expander, improves the reliability and overall efficiency of the system, avoids the influence of lubricant on the intake air volume, and has a simple structure that is easy to install and maintain.
Smart Images
Figure CN224107319U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a scroll expander assembly, more particularly, to a scroll expander assembly comprising a lubricant supply mechanism. Furthermore, the utility model also relates to an organic Rankine cycle system comprising a scroll expander assembly. BACKGROUND
[0002] The content of this section is provided only as background information related to the utility model and can not constitute the prior art.
[0003] In an organic Rankine cycle system, the scroll expander serves as a core component, and the lubrication between friction pairs, particularly between the orbiting scroll and the fixed scroll, is crucial for maintaining the normal operation of the system.
[0004] The lubrication between the orbiting scroll and the fixed scroll can be achieved by mixing lubricant in the working fluid. For example, the lubricant carried by the working fluid discharged from the scroll expander can be separated by an oil separator and temporarily stored in the oil separator. Subsequently, the lubricant in the oil separator is delivered to the inlet of the expander under the action of an oil pump, thereby entering the expander in the form of droplets or oil mist to lubricate the scroll plates of the expander. However, when the lubricant enters the high-pressure area of the expander along with the high-pressure refrigerant, there may be a phenomenon that part of the lubricant droplets accumulate in the low-lying space of the high-pressure area under the action of gravity, which reduces the amount of lubricant entering the internal structure of the expander, thereby affecting the lubrication between the scroll plates. At the same time, since the lubricant is input from the inlet of the expander, it will also affect the intake amount of the expander to some extent.
[0005] Therefore, the utility model aims to provide a better solution for lubricating the expander. SUMMARY
[0006] An object of the utility model is to provide a scroll expander assembly that directly supplies lubricant to the fluid cavity of the expansion mechanism of the scroll expander, thereby achieving effective and reliable lubrication of the expansion mechanism and avoiding the impact of the lubricant on the intake amount of the expander when the lubricant and the working fluid share the intake pipeline.
[0007] Another object of the utility model is to provide a scroll expander assembly that comprises a scroll expander and a lubricant supply mechanism. The oil pump in the lubricant supply mechanism pressurizes the lubricant, thereby providing high-pressure lubricant and improving the efficiency of the expansion mechanism by recovering the pressure / energy of the lubricant. In addition, the oil pump can also be driven by the scroll expander, which improves the overall efficiency of the scroll expander assembly.
[0008] The utility model discloses still another purpose is to provide a kind of organic rankine cycle system, the organic rankine cycle system includes the scroll expander assembly with lubricant supply mechanism, not only can guarantee the effective lubrication of core component, improve the reliability of system, and can improve the overall efficiency of system.
[0009] According to an aspect of the utility model, a scroll expander assembly is provided, comprising: a scroll expander, the scroll expander including a housing and a stationary scroll and a moving scroll disposed in an interior space enclosed by the housing, the stationary scroll including a stationary scroll end plate and helical stationary scroll vanes formed on a side of the stationary scroll end plate, the moving scroll including a moving scroll end plate and helical moving scroll vanes formed on a side of the moving scroll end plate, the stationary scroll vanes and the moving scroll vanes engage each other to form a series of fluid chambers therebetween; and a lubricant supply mechanism, wherein the lubricant supply mechanism includes a lubricant source and a lubricant supply passage, the lubricant source is disposed outside the scroll expander, and the lubricant supply passage is configured to supply lubricant from the lubricant source to at least one of the series of fluid chambers.
[0010] Optionally, the lubricant supply passage is configured to supply lubricant from the lubricant source to a central intake chamber of the series of fluid chambers.
[0011] Optionally, the lubricant source is configured as an oil separator, the oil separator is in communication with an exhaust fitting of the scroll expander for separating lubricant from working fluid discharged from the scroll expander and storing the separated lubricant in the oil separator.
[0012] Optionally, the lubricant supply passage includes an oil inlet channel formed in the stationary scroll end plate, the oil inlet channel is in communication with at least one of the series of fluid chambers.
[0013] Optionally, the stationary scroll end plate is formed with a central intake port in communication with the central intake chamber of the series of fluid chambers, one port of the oil inlet channel is in communication with the central intake port, and another port of the oil inlet channel is formed on an outer peripheral surface of the stationary scroll end plate.
[0014] Optionally, a joint is provided on the housing, and the lubricant supply passage further includes a first oil supply pipe connected to the joint outside the scroll expander and a second oil supply pipe connecting the joint and the oil inlet channel inside the scroll expander.
[0015] Optionally, an oil pump is provided in the lubricant supply passage to pressurize lubricant from the lubricant source to a predetermined pressure before supplying it to at least one of the series of fluid chambers.
[0016] Optionally, the oil pump is configured to be driven by the scroll expander.
[0017] Optionally, a one-way valve is provided in the lubricant supply passage.
[0018] Optionally, the lubricant supply channel is configured to supply lubricant from the lubricant source to only one of the series of fluid chambers.
[0019] According to another aspect of the present application, there is also provided an organic Rankine cycle system comprising the scroll expander assembly described above.
[0020] In general, the scroll expander assembly and the organic Rankine cycle system according to the present application can bring at least one of the following beneficial effects: the scroll expander assembly supplies lubricant directly to the fluid chamber of the expansion mechanism of the scroll expander through the lubricant supply mechanism (in particular, the lubricant supply mechanism having the lubricant source located outside the scroll expander), achieving effective and reliable lubrication of the expansion mechanism, improving the reliability of the system; the lubricant supply mechanism independent of the intake pipeline avoids the influence of lubricant on the intake amount of the expander, improving the efficiency of the expander; the oil pump of the lubricant supply mechanism pressurizes the lubricant and is optionally driven by the expander, further improving the efficiency of the expander and even the entire organic Rankine cycle system; the scroll expander and the lubricant supply mechanism have simple structures, are easy to install, connect and maintain. BRIEF DESCRIPTION OF DRAWINGS
[0021] The features and advantages of one or more embodiments of the present application will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings. The drawings provided herein are for illustrative purposes only and are not intended to limit the scope of the application in any way. The drawings are not necessarily to scale, as some features can be exaggerated to show details that would otherwise be difficult to see and / or to illustrate features that are not to scale. In the drawings:
[0022] Figure 1 is a schematic diagram of an organic Rankine cycle system according to an exemplary embodiment of the present application;
[0023] Figure 2 is a partial longitudinal sectional view of a scroll expander assembly according to an exemplary embodiment of the present application, in which the scroll expander and part of the lubricant supply mechanism are mainly shown; and
[0024] Figure 3 is a schematic diagram of an organic Rankine cycle system of a comparative example. DETAILED DESCRIPTION
[0025] The preferred embodiments of the present application will be described hereinafter with reference to the accompanying drawings, which are merely illustrative and not intended to limit the scope of the present application in any way. The drawings are not necessarily to scale, as some features can be exaggerated to show details that would otherwise be difficult to see and / or to illustrate features that are not to scale.
[0026] Figure 1A schematic view of an organic Rankine cycle system ES according to an example embodiment of the present application is shown. The organic Rankine cycle system ES comprises a scroll expander assembly EA and an external fluid circulation path L. The external fluid circulation path L comprises a condenser 101, a working fluid pump 102 (e.g. a fluorine pump), an evaporator 103, and a piping connecting the condenser 101, the working fluid pump 102, the evaporator 103 in sequence and connecting with the scroll expander assembly EA. The scroll expander assembly EA comprises a scroll expander 100 and a lubricant supply mechanism LS. Specifically, the external fluid circulation path L (of the piping) comprises a first fluid pipe L1 connected with an intake fitting 17 of the scroll expander 100, the first fluid pipe L1 supplying high pressure fluid from the evaporator 103 to the scroll expander 100 through the intake fitting 17, wherein a supply valve V1 is provided on the first fluid pipe L1 to facilitate controlling the flow rate of the fluid supplied to the scroll expander 100; a second fluid pipe L2 connected with an exhaust fitting 18 of the scroll expander 100, the second fluid pipe L2 being used to supply low pressure fluid discharged from the scroll expander 100 to the condenser 101; and a pumping pipe using the working fluid pump 102 to supply the fluid in the condenser 101 to the evaporator 103. In addition, the external fluid circulation path L further comprises a third fluid pipe L3 capable of communicating a high pressure zone HP (see Figure 2 ) of the scroll expander 100 with a low pressure zone LP (see Figure 2 ) of the scroll expander 100. In an example embodiment according to the present application, the third fluid pipe L3 comprises a first port and a second port opposite to each other, the first port being connected to and in communication with the first fluid pipe L1, and the second port being connected to and in communication with the second fluid pipe L2. Since the first fluid pipe L1 is in communication with the high pressure zone HP of the scroll expander 100 via the intake fitting 17, and the second fluid pipe L2 is in communication with the low pressure zone LP of the scroll expander 100 via the exhaust fitting 18, the first port L31 and the second port L32 of the third fluid pipe L3 are indirectly in communication with the high pressure zone HP and the low pressure zone LP of the scroll expander 100, respectively. A bypass valve V2 is provided on the third fluid pipe L3 to facilitate controlling the flow rate of the fluid in the third fluid pipe L3. In particular, the connection point 171 of the third fluid pipe L3 with the first fluid pipe L1 is located upstream of the supply valve V1, more specifically, between the evaporator 103 and the supply valve V1, to facilitate independent control of the flow rates in the first fluid pipe L1 and the third fluid pipe L3. In other words, the third fluid pipe L3 branches from and is in fluid communication with the first fluid pipe L1 between the supply valve V1 and the evaporator 103 to the second fluid pipe L2.
[0027] The specific configuration of the scroll expander assembly EA will be described below in connection with Figure 2 .
[0028] As shown in Figure 2As shown, the scroll expander assembly EA includes a scroll expander 100. The scroll expander 100 includes a housing 10, an expander mechanism disposed within an interior space enclosed by the housing 10, a main bearing seat 50 for supporting the expander mechanism, a rotating shaft 40 driven by the expander mechanism, and the like. The rotating shaft 40 can be connected with an electric motor (not shown in the figure) so as to drive the motor (rotor) to operate to output electric power. In other embodiments, the scroll expander 100 can also directly output mechanical power. The housing 10 can be composed of a substantially cylindrical body portion 12, a top cover 14 disposed at one end of the body portion 12, and a bottom cover (not shown) disposed at the other end of the body portion 12. The housing 10 further includes a partition plate 16 disposed between the top cover 14 and the body portion 12 to divide the interior space of the scroll expander 100 enclosed by the housing 10 into a high-pressure zone HP and a low-pressure zone LP, wherein the space between the partition plate 16 and the top cover 14 constitutes the high-pressure zone HP, and the space between the partition plate 16, the body portion 12 and the bottom cover constitutes the low-pressure zone LP. The sealing separation between the high-pressure zone HP and the low-pressure zone LP can be achieved by a floating seal S provided at the partition plate 16. An intake fitting 17 (shown in Figure 1 ) of the scroll expander 100 can be provided on the top cover 14 for introducing high-pressure fluid outside the scroll expander 100 into the high-pressure zone HP. An exhaust fitting 18 (shown in Figure 1 ) of the scroll expander 100 can be provided on the body portion 12 for discharging low-pressure fluid expanded by the expander mechanism 20 within the low-pressure zone LP out of the scroll expander 100.
[0029] The expander mechanism includes a fixed scroll 20 and an orbiting scroll 30. The orbiting scroll 30 is able to orbit relative to the fixed scroll 30 under the expansion action of the working fluid (i.e., the central axis of the orbiting scroll 30 revolves around the central axis of the fixed scroll 20, but the orbiting scroll 30 itself does not rotate around its own central axis). The fixed scroll 20 includes a fixed scroll end plate 22 and helical fixed scroll vanes 24 formed on one side of the fixed scroll end plate. A central intake port 27 is formed at a substantially central position of the fixed scroll end plate 22. The orbiting scroll 30 can include an orbiting scroll end plate 32 and helical orbiting scroll vanes 34 formed on one side of the orbiting scroll end plate 32. The fixed scroll vanes 24 and the orbiting scroll vanes 34 are able to mesh with each other to form a series of fluid chambers C between the fixed scroll vanes 24 and the orbiting scroll vanes 34, with the volume of each fluid chamber C gradually increasing from the radially inner side of the expander mechanism towards the radially outer side. The series of fluid chambers C includes an exhaust chamber located at the radially outermost side of the expander mechanism, a central intake chamber CI located at a substantially central position of the expander mechanism and communicating with the central intake port 27, and intermediate expansion chambers located between the exhaust chamber and the central intake chamber CI.
[0030] To ensure lubrication between each friction pair in the scroll expander 100, especially between the orbiting scroll 30 and the fixed scroll 20, the scroll expander assembly EA further comprises a lubricant supply mechanism LS.
[0031] Referring to Figure 1 and Figure 2 , the lubricant supply mechanism LS comprises a lubricant source and a lubricant supply passage. The lubricant source is arranged outside the scroll expander. In the exemplary embodiment according to the present application, the lubricant source is configured as an oil separator 104. The oil separator 104 is in communication with the exhaust fitting 18 of the scroll expander 100 for separating lubricant from working fluid discharged from the scroll expander 100 and storing the separated lubricant in the oil separator 104. Specifically, the oil separator 104 can be arranged in the fluid path between the exhaust fitting 18 of the scroll expander 100 and the condenser 101, for example, in (or connected with) the second fluid pipe L2. More specifically, the oil separator 104 can be arranged in the fluid path between the exhaust fitting 18 of the scroll expander 100 and the connection point 181 of the third fluid pipe L3 and the second fluid pipe L2.
[0032] The lubricant supply passage is configured to supply lubricant from the lubricant source to at least one of the series of fluid cavities C of the expansion mechanism of the scroll expander 100. Specifically, the lubricant supply passage comprises a first oil supply pipe P1 arranged outside the scroll expander 100, a second oil supply pipe P2 arranged inside the scroll expander 100, and an oil inlet channel 25 formed in the fixed scroll end plate. The first oil supply pipe P1, the second oil supply pipe P2 and the oil inlet channel 25 are connected with each other, and the first oil supply pipe P1 can be connected (directly or indirectly) to the oil separator 104, and the oil inlet channel 25 can be communicated to at least one of the series of fluid cavities C. Thus, lubricant in the oil separator 104 can be supplied to at least one of the series of fluid cavities C via the lubricant supply passage, i.e., via the first oil supply pipe P1, the second oil supply pipe P2 and the oil inlet channel 25. Preferably, the lubricant supply passage is configured to supply lubricant from the lubricant source to only one of the series of fluid cavities C of the expansion mechanism of the scroll expander 100, thereby reducing or avoiding the possibility that two or more fluid cavities can be communicated with each other via the lubricant supply passage, in particular, via the oil inlet channel 25, which can affect the performance of the scroll expander.
[0033] The operation process of the scroll expander assembly EA, in particular, the lubrication process of each component in the scroll expander 100, will be described below.
[0034] When the scroll expander 100 is in operation, high-pressure working fluid provided by the first fluid pipe L1 enters the high-pressure region HP within the scroll expander 100 via the intake fitting 17, and then enters the expansion mechanism 20 via the central intake port 27 of the fixed scroll 20. The high-pressure working fluid entering the expansion mechanism 20 is expanded and becomes low-pressure fluid as it flows through a series of fluid chambers C with gradually increasing volumes. At the same time, the lubricant supply channel can supply lubricant from the lubricant source (i.e., the oil separator 104) to at least one of the series of fluid chambers C. In the fluid chambers, the lubricant forms droplets or oil mist and mixes with the working fluid, thereby providing lubrication to the fixed scroll and the orbiting scroll. Subsequently, the lubricant is discharged with the low-pressure working fluid after expansion by the expansion mechanism 20 into the low-pressure region LP outside the expansion mechanism, thereby lubricating parts such as the thrust face between the main bearing seat 50 and the orbiting scroll end plate 32, the main bearings in the main bearing seat 50, etc. The mixture of lubricant and working fluid in the low-pressure region LP is then discharged to the outside of the scroll expander 100 via the exhaust fitting 18. The driving torque is generated in the process of expansion of the working fluid by the expansion mechanism, which drives the rotation of the rotating shaft 40, thereby driving the rotation of the motor (or the rotor of the motor, not shown in the figure). The mixture of lubricant and working fluid discharged to the outside of the scroll expander 100 is transported to the oil separator 104 via the second fluid pipe L2. The oil separator 104 separates the mixture of lubricant and working fluid into lubricant and working fluid. The lubricant can be temporarily stored in the oil separator 104 and can be supplied to the scroll expander 100 again via the lubricant supply channel for the next lubrication cycle if necessary. The working fluid is transported to the condenser 101 via the second fluid pipe L2 to enter the system cycle.
[0035] In the example embodiment according to the present application, since the lubricant supply mechanism LS directly supplies lubricant to the vicinity of the parts to be lubricated within the scroll expander, i.e., to at least one of the fluid chambers of the expansion mechanism, sufficient and effective lubrication can be provided for the fixed scroll and the orbiting scroll, thereby improving the reliability of the system.
[0036] In contrast, the organic Rankine cycle system ES' of the comparative example has the risk of insufficient lubrication of the scroll expander. Referring to Figure 3 The basic structure and working principle of the organic Rankine cycle system ES' of the comparative example are basically the same as those of the organic Rankine cycle system ES in the example embodiment of the present application, and will not be described here. The main difference is that the organic Rankine cycle system ES' does not have a separate lubricant supply mechanism, in particular, a lubricant supply channel independent of the circulation path of the working fluid.
[0037] As Figure 3As shown, in the organic Rankine cycle system ES', the oil separator 104 is in communication with the exhaust fitting 18 of the scroll expander 100' for separating lubricant from the working fluid discharged from the scroll expander 100' and storing the separated lubricant in the oil separator 104. In addition, a lubricant supply pipe P' is further provided between the oil separator 104 and the first fluid pipe L1. The lubricant supply pipe P' can be further connected with an oil pump 105 for providing pressure to the lubricant. In need, the lubricant in the oil separator 104 can be supplied to the first fluid pipe L1 via the lubricant supply pipe P' and mixed with the working fluid in the first fluid pipe L1. In this way, the lubricant can enter the high pressure area HP of the scroll expander 100' along with the working fluid and then enter the inside of the expander mechanism along with the working fluid to lubricate the components of the scroll expander 100'. However, referring to Figure 2 As shown in the structure of the scroll expander 100, due to the low-lying space (approximately at the position where the top cover 14 is connected with the partition plate 16) in the high pressure area HP, part of the lubricant droplets or oil mist mixed in the working fluid can drop or flow to the low-lying space under the action of gravity, so as to fail to enter the inside of the expander mechanism along with the working fluid. That is, the lubricant can accumulate in the low-lying space, resulting in a decrease in the amount of lubricant in the inside of the expander mechanism, or even a decrease in the amount of lubricant in the system circulation, affecting the lubrication effect.
[0038] Unlike the comparative example, in the organic Rankine cycle system according to the exemplary embodiment of the present application, the lubricant supply mechanism LS, in particular the lubricant supply passage independent of the circulation path of the working fluid, can directly supply the lubricant to the inside of the expander mechanism, so that the lubricant does not accumulate in the invalid position (e.g. the low-lying space) of the scroll expander, thereby being able to provide sufficient and reliable lubrication to each component to be lubricated, such as the fixed scroll and the orbiting scroll, in the scroll expander. In addition, in the organic Rankine cycle system according to the exemplary embodiment of the present application, since the lubricant supply passage is provided independently of the circulation path of the working fluid, the supply of the lubricant does not affect the intake amount of the scroll expander, which is beneficial to improve the efficiency of the expander.
[0039] Preferably, in order to further improve the lubrication effect, the lubricant supply passage can be configured to supply the lubricant from the lubricant source (the oil separator 104) to the central intake cavity CI among the series of fluid cavities C of the scroll expander 100. Thereby, the lubricant can be gradually moved from the central intake cavity CI to the fluid cavities radially outward under the entrainment of the working fluid, so that more sufficient and comprehensive lubrication can be provided to the scroll wrap. Specifically, the oil inlet channel of the lubricant supply passage can be configured to include a horizontal section and a vertical section, one port of the horizontal section is formed on the outer peripheral surface of the fixed scroll end plate 22 so as to communicate with the second oil supply pipe P2, the other port of the horizontal section is connected with one port of the vertical section, the other port of the vertical section is formed on the lower surface of the fixed scroll end plate 22 within the central intake cavity CI so as to communicate with the central intake cavity CI. More preferably, in order to simplify the structure, facilitate the machining and installation, as shown in FIG. 2, the oil inlet channel 25 can be configured to be substantially horizontal, one port of the oil inlet channel 25 communicates with the central intake port 2 (i.e. formed on the inner wall surface of the fixed scroll end plate 22 defining the central intake port 2), so that the central intake cavity CI is communicated; the other port of the oil inlet channel 25 is formed on the outer peripheral surface of the fixed scroll end plate 22 so as to communicate with the second oil supply pipe P2. Figure 2
[0040] Preferably, as shown in FIG. 2, in order to facilitate the installation, maintenance and replacement of the lubricant supply passage (particularly the first oil supply pipe P1 and the second oil supply pipe P2), the housing 10 of the scroll expander 100 can be provided with a joint 19, the first oil supply pipe P1 of the lubricant supply passage can be connected with the joint 19, and one end of the second oil supply pipe P2 can be connected with the joint 19, and the other end can be connected with the oil inlet channel 25. However, on the other hand, those skilled in the art can understand that the first oil supply pipe P1 and the second oil supply pipe P2 can also be formed as an integral pipe which can directly pass through the housing 10 to be connected with the fixed scroll 20 so as to communicate with the oil inlet channel 25 in the fixed scroll end plate 22. Figure 2
[0041] Preferably, a one-way valve is provided in the lubricant supply passage. For example, as shown in FIG. 2, the one-way valve VP can be provided in the second oil supply pipe P2. The one-way valve VP only allows the fluid to flow in the direction from the lubricant source towards at least one fluid cavity of the expander mechanism, and prevents the fluid in the fluid cavity of the expander mechanism from flowing outside the expander, thereby preventing the undesirable reverse flow and leakage of the expander. In the figure, the one-way valve is only schematically shown. Those skilled in the art can understand that the one-way valve can be any suitable type of valve, such as a spring-type one-way valve. Figure 2
[0042] Preferably, an oil pump 105 is provided in the lubricant supply passage to pressurize the lubricant from the lubricant source to a predetermined pressure and then supply it to at least one of the series of fluid chambers C. For example, as shown in Figure 1 the oil pump 105 is provided on the first oil supply pipe PI for ease of installation and maintenance. Since the lubricant is supplied at a predetermined pressure, it is possible to avoid the lubricant reducing the pressure of the working fluid in the fluid chamber, thereby improving the efficiency of the expander. In addition, the pressure / energy of the lubricant can also be recovered by the expander to further improve the efficiency of the expander. The oil pump 105 can be driven by other power sources, but more preferably, the oil pump 105 can be configured to be driven by the scroll expander 100, thereby improving the overall efficiency of the system.
[0043] The scroll expander assembly and the organic Rankine cycle system according to the preferred embodiments of the present application are described above in conjunction with the specific embodiments. It can be understood that the above description is only exemplary and not limiting, and those skilled in the art can think of various modifications and changes with reference to the above description without departing from the scope of the present application. These modifications and changes are also included in the scope of protection of the present application.
Claims
1. A scroll expander assembly comprising: a scroll expander including a housing and a fixed scroll and an orbiting scroll disposed in an internal space enclosed by the housing, the fixed scroll including a fixed scroll end plate and helical fixed scroll vanes formed on one side of the fixed scroll end plate, the orbiting scroll including an orbiting scroll end plate and helical orbiting scroll vanes formed on one side of the orbiting scroll end plate, the fixed scroll vanes and the orbiting scroll vanes engaging each other to form a series of fluid pockets therebetween; and a lubricant supply mechanism, characterized in that the lubricant supply mechanism includes a lubricant source disposed outside the scroll expander and a lubricant supply passage configured to supply lubricant from the lubricant source to at least one of the series of fluid pockets.
2. The scroll expander assembly of claim 1, wherein, the lubricant supply passage is configured to supply lubricant from the lubricant source to a central intake pocket of the series of fluid pockets.
3. The scroll expander assembly of claim 1, wherein, the lubricant source is configured as an oil separator in communication with an exhaust fitting of the scroll expander for separating lubricant from working fluid discharged from the scroll expander and storing the separated lubricant in the oil separator.
4. The scroll expander assembly of claim 1, wherein, the lubricant supply passage includes an oil inlet channel formed in the fixed scroll end plate, the oil inlet channel being in communication with at least one of the series of fluid pockets.
5. The scroll expander assembly of claim 4, wherein, the fixed scroll end plate is formed with a central intake port in communication with the central intake pocket of the series of fluid pockets, one port of the oil inlet channel being in communication with the central intake port, the other port of the oil inlet channel being formed on an outer peripheral surface of the fixed scroll end plate.
6. The scroll expander assembly of claim 4, wherein, the housing is provided with a joint, the lubricant supply passage further including a first oil supply tube connected to the joint outside the scroll expander and a second oil supply tube connecting the joint to the oil inlet channel inside the scroll expander.
7. The scroll expander assembly of any one of claims 1 to 6, wherein, the lubricant supply passage is provided with an oil pump to pressurize lubricant from the lubricant source to a predetermined pressure before supplying it to at least one of the series of fluid pockets.
8. The scroll expander assembly of claim 7, wherein, the oil pump is configured to be driven by the scroll expander.
9. The scroll expander assembly of any one of claims 1 to 6, wherein, the lubricant supply passage is provided with a check valve.
10. The scroll expander assembly of any one of claims 1 to 6, wherein, the lubricant supply passage is configured to supply lubricant from the lubricant source to only one of the series of fluid pockets.
11. An organic Rankine cycle system, characterized by, the organic Rankine cycle system includes the scroll expander assembly according to any one of claims 1 to 10.