Water-cooled oil-free scroll air compressor with double water inlet and outlet structure

Abstract

The application relates to the technical field of scroll compressors, and discloses a water-cooled oil-free scroll air compressor with a double-inlet and double-outlet water structure, which comprises a machine shell, a static scroll disc arranged in the machine shell, a dynamic scroll disc coupled with the static scroll disc, and a main bearing seat for supporting a crankshaft, the machine shell is internally provided with a first cooling loop and a second cooling loop which are independent of each other, the first cooling loop is arranged in the static scroll disc and comprises a profile line gradually expanding spiral water channel, a water inlet of the profile line gradually expanding spiral water channel is arranged in a central exhaust area of the static scroll disc, and a water outlet is arranged in an outer ring air suction area of the static scroll disc, and the second cooling loop is arranged in the machine shell. The profile line gradually expanding spiral water channel radiating from the center to the outer ring is constructed in the static scroll disc, the distribution rule of the heat flow density of the scroll disc radially decreasing is ingeniously matched, unnecessary fluid resistance in the peripheral low-temperature area is effectively reduced, and the precise engagement of the flow velocity distribution and the local heat exchange demand is realized under the premise that the pumping pressure does not need to be additionally increased.

Description

Technical Field

[0001] This invention relates to the field of scroll compressor technology, specifically to a water-cooled oil-free scroll air compressor with a dual-inlet / outlet water structure. Background Technology

[0002] In high-end manufacturing, medical equipment, and new energy vehicles—fields with extremely high requirements for air quality—oil-free scroll air compressors are gradually becoming irreplaceable core power components due to their inherent advantages of zero-oil lubrication, stable operation, and compact structure. However, because the traditional lubricating oil medium, which serves the triple functions of lubrication, sealing, and cooling, is completely eliminated from the compression chamber, the thermal management of the entire machine faces unprecedented challenges. During high-speed oil-free meshing of the scroll discs, the adiabatic latent heat of compression of the gas and the frictional heat of the solids at the tooth ends are superimposed, resulting in a highly non-uniform and gradient three-dimensional thermal field inside the compressor. Especially in the exhaust region near the geometric center of the stationary scroll disc, the local heat flux density often approaches the material's tolerance limit.

[0003] Existing water-cooled oil-free scroll air compressors generally exhibit limitations in their underlying architecture when dealing with such extreme non-uniform thermal fields. Traditional cooling water circuit designs are often constrained by compromises in terms of manufacturing convenience and simple casing structure, frequently employing a single water jacket in global series or a simple annular flow channel. This crude, flood-style cooling strategy forces the cooling water, after flowing through the peripheral areas with low heat loads, to aggressively attack the high-temperature central exhaust zone, which requires the largest temperature difference for heat exchange. The irreversible temperature rise and decay along the water flow path directly leads to a severe deficiency in the cooling capacity of the core area, easily causing thermal stress concentration at the root of the scroll teeth and uncontrolled thermal deformation at the tooth tip, ultimately consuming the already small radial and axial meshing clearances.

[0004] Meanwhile, besides the main heat source, the scroll plate, the main bearing housing supporting the high-speed rotation of the crankshaft and the back pressure chamber responsible for axial flexible sealing are also independent heat sources that cannot be ignored. In the existing series-connected single-channel water system architecture, these spatially isolated heat-generating nodes are forced to share the same coolant. This passive binding not only exacerbates the overall water system's flow resistance and pressure pulsation but also causes the temperature states of different areas to mutually constrain and contaminate each other. If the rubber seals in the back pressure chamber age and fail more rapidly due to the high-temperature water from upstream, it will directly lead to the collapse of the entire machine's axial seal; and the long-distance cooling branch pipes forcibly installed for the bearing housing are often accompanied by complex dynamic sealing designs and leakage risks.

[0005] Even more critically, existing thermal control systems that rely solely on external sensors and electrically controlled water valves are too slow and fragile in the face of sudden localized cooling failures or extreme heat caused by short-term overload operation. Once electronic components drift and malfunction under severe vibration or high-temperature conditions, the entire machine loses its last line of thermodynamic defense. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a water-cooled oil-free scroll air compressor with a dual-inlet and dual-outlet water structure. This solves the problems of local cooling failure under extreme non-uniform thermal fields, heat superposition and coupling caused by cooling multiple heat sources in series, and slow response and easy failure of the thermal control system when facing sudden overload conditions in existing oil-free scroll compressors.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a water-cooled oil-free scroll air compressor with a dual-inlet / outlet water structure, comprising a housing, a stationary scroll plate disposed within the housing, a moving scroll plate coupled to the stationary scroll plate, and a main bearing housing for supporting a crankshaft. The housing contains an independent first cooling circuit and a second cooling circuit. The first cooling circuit is located inside the stationary scroll plate and includes a contoured, gradually expanding spiral water channel. The inlet of the contoured, gradually expanding spiral water channel is located in the central exhaust area of ​​the stationary scroll plate, and the outlet is located in the outer ring intake area of ​​the stationary scroll plate. The second cooling circuit is located within the housing and adopts a parallel structure, including a back pressure chamber annular cooling jacket and a spiral groove. The back pressure chamber annular cooling jacket is located on the inner wall of the housing corresponding to the back flange of the moving scroll plate, and the spiral groove is formed on the outer wall of the main bearing housing.

[0008] Preferably, the planar projection profile of the contoured spiral channel maintains a geometrical contouring relationship with the vortex tooth profile of the stationary vortex disk, and the cross-sectional area of ​​the contoured spiral channel gradually expands along the water flow direction, that is, the cross-sectional area at the inlet end is smaller than the cross-sectional area at the outlet end.

[0009] Preferably, the second cooling circuit further includes an inlet water distribution chamber and a main drain pipe. The inlet water distribution chamber is located on the side wall of the housing and has a fixed throttling orifice inside. After the external cooling water enters the inlet water distribution chamber, it is distributed proportionally to the annular cooling jacket and spiral groove of the back pressure chamber through the fixed throttling orifice, and then flows into the main drain pipe.

[0010] Preferably, the interior of the static vortex disk is further provided with a thermal isolation structure, which is an annular narrow groove located between the contoured gradually expanding spiral water channel and the mounting stop of the static vortex disk. The annular narrow groove is filled with a non-metallic material with low thermal conductivity to block the radial conduction of heat from the central exhaust area of ​​the static vortex disk to the casing.

[0011] Preferably, the bottom of the static vortex disk is provided with multiple stress concentration relief grooves. The multiple stress concentration relief grooves extend radially along the side wall of the contoured spiral channel. The width and depth of the stress concentration relief grooves gradually narrow from the center to the outer ring of the static vortex disk, and have a spatial geometric correspondence with the gradually expanding cross-sectional area of ​​the contoured spiral channel, so that the high thermal stress concentration area obtains the maximum stress relief cross section.

[0012] Preferably, the casing wall is provided with a thermosensitive solid-state throttling cross-loop compensation microchannel. The thermosensitive solid-state throttling cross-loop compensation microchannel connects the area near the inlet of the first cooling circuit with the inlet water distribution chamber of the second cooling circuit. A bimetallic throttling insert is embedded inside the thermosensitive solid-state throttling cross-loop compensation microchannel. Under normal operating temperature, the bimetallic throttling insert remains bent to block the thermosensitive solid-state throttling cross-loop compensation microchannel. When the temperature in the area near the inlet of the first cooling circuit rises abnormally, the bimetallic throttling insert is heated and bends in the opposite direction to open the thermosensitive solid-state throttling cross-loop compensation microchannel, allowing the cooling water to perform cross-loop compensation.

[0013] Preferably, at the water outlet ends of the annular cooling jacket and the spiral groove of the back pressure cavity, and before they merge into the main drain pipe, a water outlet stabilizing cavity is provided. The internal cross-section of the water outlet stabilizing cavity is enlarged relative to its inlet cross-section, and the inner wall of the water outlet stabilizing cavity is provided with several staggered guide ribs along the water flow direction.

[0014] Preferably, the staggered flow guide ribs are arranged in two rows, with the staggered flow guide ribs in adjacent rows being staggered in the circumferential position, and the long axis of each staggered flow guide rib being deflected at an angle relative to the main flow direction to disrupt the uneven velocity distribution.

[0015] Preferably, the back pressure cavity annular cooling jacket is a stationary annular cavity structure fixedly installed on the inner wall of the housing. The back pressure cavity annular cooling jacket maintains a gap with the back flange of the moving scroll and does not directly contact it. The back pressure cavity area is indirectly cooled by heat conduction through the metal wall of the housing.

[0016] Preferably, the water-cooled oil-free scroll air compressor has four independent cooling water inlets: The first interface is the water inlet pipe of the first cooling circuit, located in the center area of ​​the top of the static vortex plate; The second interface is the outlet pipe of the first cooling circuit, located in the outer ring area on the side of the static vortex plate. The third interface is the water inlet pipe for the second cooling circuit, located on the side wall of the casing; The fourth interface is the water outlet pipe for the second cooling circuit, located at the bottom of the casing.

[0017] This invention provides a water-cooled oil-free scroll air compressor with a dual-inlet / outlet water structure. It has the following advantages: 1. This invention abandons the traditional global flooding water jacket design. Instead, it constructs a contoured, gradually expanding spiral water channel radiating outwards from the center within the stationary vortex disk, allowing the lowest initial temperature cooling water to directly reach the core exhaust zone with the heaviest heat load. The cross-sectional area of ​​the water channel gradually expands as the cooling water heats up along its path, cleverly matching the radially decreasing heat flux density distribution of the vortex disk and effectively reducing unnecessary fluid resistance in the outer low-temperature zone. This achieves precise matching between flow velocity distribution and local heat exchange requirements without requiring additional pumping pressure. Simultaneously, a gradually changing stress concentration release groove is concealed in the transition zone at the root of the stationary vortex disk, constructing a passive thermal stress conduction mechanism based on microstructural deformation. The geometric narrowing trend of these radial micro-grooves forms a strict topological correspondence with the gradual expansion direction of the inner cooling water channels. This transforms the high-intensity thermal stress, which could otherwise spread randomly or even cause deep tearing of the disc, into small and controllable opening and closing deformations at the pre-set groove openings. This eliminates the potential for tooth tip distortion and uncontrolled clearance caused by thermal expansion and contraction from the root of solid mechanics. Furthermore, considering the inherent heat diffusion tendency of the high thermal conductivity metal disc, this invention forcibly weds an annular thermal break bridge filled with low thermal conductivity material between the cooling water channels and the outer mounting stop. This physical barrier acts like a damping dam, precisely cutting off the bypass channels for the disordered conduction of high temperature to the external casing. It forces the heat accumulated in the core compression zone to converge unidirectionally towards the internal spiral water flow, thereby forcibly locking in the expected temperature field distribution pattern and greatly increasing the actual heat capture rate of the first cooling circuit.

[0018] 2. This invention addresses the two spatially isolated heat sources—the back pressure chamber and the main bearing—by employing an independent, parallel second cooling circuit. This completely eliminates the chronic problem in traditional series water cooling systems where the downstream heat exchange capacity declines due to the upstream water absorbing heat and increasing its temperature. In particular, the back pressure chamber cooling branch utilizes a stationary annular jacket fixed to the casing side, relying on the interfacial heat conduction of the casing's metal wall to extract accumulated heat. This not only creates a stable, low-temperature operating environment for the seals but also fundamentally avoids the complex dynamic seal leakage risk inherent in directly cooling the moving scroll.

[0019] 3. This invention utilizes the combination of a thermosensitive solid-state throttling cross-loop compensation microchannel and a bimetallic strip's inherent reverse bending characteristics under critical temperature rise. If the first cooling circuit's water inlet area encounters abnormally hot conditions, the microchannel will spontaneously expand due to material thermal deformation, diverting fresh cold water from adjacent parallel circuits into the danger zone for emergency suppression. The entire dynamic compensation process completely eliminates reliance on fragile electronic sensors and electrically controlled valves, endowing the oil-free scroll compressor with extremely high thermal tolerance and self-rescue capability in the event of a single-circuit water system failure. Attached Figure Description

[0020] Figure 1 This is a perspective view of the present invention; Figure 2This is a schematic diagram of the internal structure of the casing in this invention; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 for Figure 2 Enlarged view at point B in the middle; Figure 5 for Figure 2 Enlarged view at point C; Figure 6 This is a three-dimensional schematic diagram of the stationary scroll plate, the moving scroll plate, and the main bearing housing in this invention. Figure 7 This is a bottom-view three-dimensional schematic diagram of the stationary vortex disk in this invention; Figure 8 This is a three-dimensional schematic diagram of the top cross-section of the stationary vortex disk in this invention.

[0021] The components include: 1. Housing; 2. Static scroll; 3. Moving scroll; 4. Crankshaft; 5. Main bearing housing; 6. Contouring spiral water channel; 7. Back pressure chamber annular cooling jacket; 8. Spiral groove; 9. Inlet water distribution chamber; 901. Fixed throttling orifice; 10. Main drain pipe; 11. Annular narrow groove; 12. Stress concentration relief groove; 13. Thermosensitive solid throttling cross-loop compensation microchannel; 14. Bimetallic throttling insert; 15. Outlet water flow stabilizing chamber; 16. Staggered guide ribs; 17. First interface; 18. Second interface; 19. Third interface; 20. Fourth interface. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see the appendix Figure 1 - Appendix Figure 8This invention provides a water-cooled oil-free scroll air compressor with a dual-inlet / outlet water structure. By constructing two mutually isolated liquid heat exchange paths in space, the overall thermal field distribution pattern of the oil-free scroll compressor is reshaped. The water-cooled oil-free scroll air compressor includes a housing 1, a stationary scroll 2 disposed within the housing 1, a moving scroll 3 coupled to the stationary scroll 2, and a main bearing housing 5 for supporting a crankshaft 4. The housing 1 contains independent first and second cooling circuits. The first cooling circuit is located inside the stationary scroll 2 and includes a contoured, gradually expanding spiral water channel 6. The inlet of the contoured, gradually expanding spiral water channel 6 is located in the central exhaust area of ​​the stationary scroll 2, and the outlet is located in the outer ring intake area of ​​the stationary scroll 2. The second cooling circuit is located within the housing 1 and adopts a parallel structure, including a back pressure chamber annular cooling jacket 7 and a spiral groove 8. The back pressure chamber annular cooling jacket 7 is located on the inner wall of the housing 1 corresponding to the back flange of the moving scroll 3, and the spiral groove 8 is formed on the outer wall of the main bearing housing 5.

[0024] The water-cooled oil-free scroll air compressor has four independent cooling water inlets: The first interface 17 is the water inlet pipe of the first cooling circuit, located in the center area of ​​the top of the static vortex plate 2; The second interface 18 is the outlet pipe of the first cooling circuit, located in the outer ring area on the side of the static vortex plate 2. The third interface 19 is the water inlet pipe for the second cooling circuit, located on the side wall of the casing 1; The fourth interface 20 is the water outlet pipe for the second cooling circuit, located at the lower part of the casing 1.

[0025] The housing 1 serves as the external load-bearing frame of the entire machine, and its interior contains enclosed chambers to house the various core operating components. The stationary scroll 2 is fixedly mounted on the upper end of the housing 1, and the scroll teeth protruding from its lower surface interlock with the scroll teeth on the upper surface of the moving scroll 3.

[0026] The moving scroll 2 is connected to the crankshaft 4 via a flange structure on its back and performs translational rotation under the constraint of the anti-rotation mechanism. As the moving scroll 2 moves eccentrically, the crescent-shaped closed compression cavity formed by the meshing of the two scroll teeth continuously contracts from the periphery to the geometric center, achieving oil-free adiabatic compression of the intake gas.

[0027] The main bearing housing 5 is located below the moving scroll 2, and is internally fitted with a bearing assembly that supports the high-speed rotation of the crankshaft 4. In each working area of ​​the aforementioned moving components, due to the avoidance of direct intervention of lubricating oil, the heat of gas compression, the heat of tooth tip friction, and the heat of bearing mechanical friction exhibit extremely high local heat flux density at different spatial nodes.

[0028] To achieve precise separation and suppression of the aforementioned multi-source heterogeneous thermal field, this invention incorporates two independent cooling circuits within the entire unit. Each of the two liquid circuits is spatially anchored to a specific core area of ​​the thermal load, and is completely decoupled at the hydraulic level, preventing any flow or interference between them.

[0029] To support the independent dual-loop fluid operation, the outer surface of the entire machine is equipped with four cooling water interfaces that are in a state of absolute physical isolation.

[0030] The first interface 17 is defined as the inlet pipe of the first cooling circuit, and its spatial position is anchored in the center area of ​​the top of the stationary scroll 2. This position is directly opposite the high-temperature exhaust core of the compressor, ensuring that the initial cooling water with the strongest cooling capacity enters the highest heat load area of ​​the whole machine first.

[0031] The second interface 18 is defined as the outlet pipe of the first cooling circuit and is located in the outer ring area on the side of the stationary vortex plate 2. The coolant, after absorbing the latent heat of compression, is discharged from the main unit through this interface, completing the active heat removal of the solid phase thermal field inside the stationary vortex plate 2.

[0032] The third interface 19 is defined as the water inlet pipe of the second cooling circuit and is located on the outer wall of the casing 1. This interface serves as the connection hub for the independent cold source inside the casing 1 and the core components in the lower half, and is responsible for supplying low-temperature fluid that is not contaminated by compression heat to the multiple heat-generating elements below.

[0033] The fourth interface 20 is defined as the manifold outlet pipe of the second cooling circuit, fixed to the lower part of the casing 1, and connected to the manifold drain pipe 10. This interface is responsible for draining the waste heat of the independent cooling branch below, completing the final fluid release of the whole machine's dual inlet and outlet water architecture.

[0034] The planar projection profile of the contoured spiral channel 6 maintains a geometrical contouring relationship with the vortex tooth profile of the stationary vortex disk 2. The cross-sectional area of ​​the contoured spiral channel 6 gradually expands along the water flow direction, that is, the cross-sectional area at the inlet end is smaller than the cross-sectional area at the outlet end.

[0035] To provide targeted thermal management for the compression work zone, where the heat load is most concentrated, the first cooling circuit is entirely enclosed within the casing of the stationary scroll 2. This circuit is spatially integrated with the solid substrate of the stationary scroll 2 itself, forming a highly efficient heat-absorbing layer that directly surrounds the compression chamber.

[0036] The core structure of the first cooling circuit is a contoured, gradually expanding spiral water channel 6 embedded inside the stationary vortex disk 2. This contoured, gradually expanding spiral water channel 6 is not a traditional simple annular or straight channel, but a customized fluid channel that closely follows the trend of the heat source in three-dimensional space.

[0037] Specifically, the planar projection profile of the gradually expanding spiral water channel 6 maintains a precise geometrical conformation relationship with the vortex tooth profile of the stationary vortex disk 2. The centerline of this water channel extends spirally outward from the geometric center of the stationary vortex disk 2 along the unfolding path of the vortex teeth. Thus, the flow trajectory of the cooling water corresponds segment by segment geometrically to the distribution pattern of the compression chamber.

[0038] In this embodiment, the inlet of the contoured expanding spiral water channel 6 is strictly positioned in the central exhaust zone of the stationary vortex disk 2, while its outlet is located in the outer ring intake zone of the stationary vortex disk 2. During the operating cycle of the oil-free scroll compressor, gas is drawn in from the periphery and compressed step by step towards the center, resulting in the highest intensity of latent heat of compression accumulating in the central exhaust zone.

[0039] Relying on the aforementioned water inlet and outlet layout, the initial temperature cooling water introduced by the system directly hits the central exhaust area. The liquid medium with the strongest cooling capacity and the solid metal with the highest heat flux density in the entire machine converge here, and the two constitute the driving force for the largest heat exchange temperature difference inside the entire machine, completing the powerful cooling of the core high-temperature area.

[0040] Meanwhile, the cross-sectional area of ​​the contoured, gradually expanding spiral channel 6 gradually increases along the fluid flow direction. That is, the cross-sectional area of ​​the water inlet located in the central exhaust zone is the smallest, while the cross-sectional area of ​​the water outlet extending to the outer ring intake zone is the largest. This gradually expanding structure makes the physical flow space inside the channel exhibit a continuous gradient change.

[0041] The aforementioned gradually expanding cross-sectional area design aligns with the radially decreasing heat flux density distribution of the static vortex disk 2 from the center outwards. At the narrow inlet end, the limited flow channel cross-section forces the cooling water to maintain a high flow velocity, using a high convective heat transfer coefficient to cope with the high heat load in the central area. As the water flow advances along the spiral towards the outer ring, the water temperature itself gradually increases, while the corresponding local heat load of the disk also decreases synchronously.

[0042] During this process, the gradual expansion of the flow channel cross-section causes a decrease in local water flow velocity. This structural design, while meeting the heat dissipation requirements of the low heat load area in the outer ring, eliminates the dynamic pressure loss caused by maintaining an unnecessarily high flow velocity in the low heat flux density area, and keeps the fluid resistance of the entire first cooling circuit within a reasonable range.

[0043] The interior of the stationary vortex disk 2 is also equipped with a thermal isolation structure, which is an annular narrow groove 11 located between the contoured gradually expanding spiral water channel 6 and the mounting stop of the stationary vortex disk 2. The annular narrow groove 11 is filled with a non-metallic material with low thermal conductivity to block the radial conduction of heat from the central exhaust area of ​​the stationary vortex disk 2 to the casing 1.

[0044] The bottom of the static vortex disk 2 is provided with multiple stress concentration relief grooves 12. The multiple stress concentration relief grooves 12 extend radially along the side wall of the contoured spiral channel 6. The width and depth of the stress concentration relief grooves 12 gradually narrow from the center to the outer ring of the static vortex disk 2, and have a spatial geometric correspondence with the gradually expanding cross-sectional area of ​​the contoured spiral channel 6, so that the high thermal stress concentration area obtains the maximum stress relief section.

[0045] To address the high thermal conductivity of the metal substrate inside the stationary vortex disk 2, a blocking thermal isolation structure is embedded in the outer region of the first cooling circuit. This thermal isolation structure is located within the solid disk area between the contoured gradually expanding spiral water channel 6 and the mounting stop of the stationary vortex disk 2, and forms a completely closed annular narrow groove 11.

[0046] The annular narrow groove 11 is densely filled with a non-metallic material with low thermal conductivity. This low thermal conductivity boundary forms a physical barrier layer inside the static vortex disk 2, cutting off the bypass of solid heat that is radially conducted from the high temperature of the core compression zone to the external casing 1 and mounting flange surface. The intercepted high-density heat flow is impeded by this barrier layer, forcibly changing its internal conduction path and flowing directly into the contoured spiral water channel 6 along a direction perpendicular to the disk surface, where it is rapidly stripped away by the forced-circulation coolant.

[0047] In this embodiment, to address the thermomechanical deformation induced by the non-uniform thermal field in the solid matrix, a stress concentration relief groove 12 is provided in the bottom region of the stationary vortex disk 2. Specifically, this stress concentration relief groove 12 is a group of radial micro-grooves distributed in the region extending from the transition fillet at the root of the vortex teeth towards the disk body. The length of each micro-groove extends radially along the disk body, closely adhering to the inner wall of the contoured, gradually expanding spiral channel 6, and is arranged in a periodic array along the vortex profile.

[0048] The stress concentration relief groove 12 has a non-uniform cross-sectional distribution. Its groove width (short axis direction) and groove depth follow the vortex profile of the stationary vortex disk 2, exhibiting a continuous gradual narrowing characteristic from the central exhaust zone to the outer ring intake zone. The micro-grooves near the geometric center of the stationary vortex disk have the largest opening cross-sectional area, while the cross-section of the micro-grooves located on the outer ring of the disk edge shrinks to its minimum shape.

[0049] The gradual narrowing trend of the aforementioned micro-channels and the gradual expansion direction of the cross-sectional area of ​​the contoured spiral water channel 6 in the first cooling circuit constitute a precise geometric correspondence on a three-dimensional scale. In the central water inlet region where the heat load and thermal stress gradient are most intense, the inner water channel with the smallest cross-section outputs the strongest heat transfer coefficient, while the inner micro-channel with the largest cross-section provides the most ample volume for material stress release.

[0050] As the spatial position shifts outwards, the expanding outer channels and narrowing micro-grooves once again create an inverse mechanical and thermal match. The high-intensity, non-uniform thermal stress generated during operation, before accumulating at the tooth root to the material's critical failure value, is directly transformed into localized micro-elastic tension deformation at the micro-groove openings. Through the aforementioned physical weakening and structural relocation of the disk substrate, the system achieves a deep mechanistic synergy between solid-state deformation constraint and liquid-state heat dissipation.

[0051] The second cooling circuit also includes an inlet water distribution chamber 9 and a main drain pipe 10. The inlet water distribution chamber 9 is located on the side wall of the housing 1 and has a fixed throttling orifice 901 inside. After the external cooling water enters the inlet water distribution chamber 9, it is distributed proportionally to the annular cooling jacket 7 and the spiral groove 8 of the back pressure chamber through the fixed throttling orifice 901, and then flows into the main drain pipe 10.

[0052] The back pressure cavity annular cooling jacket 7 is a stationary annular cavity structure fixedly installed on the inner wall of the housing 1. The back pressure cavity annular cooling jacket 7 and the back flange of the moving scroll 3 are separated by a gap and do not directly contact each other. The back pressure cavity area is indirectly cooled by heat conduction through the metal wall of the housing 1.

[0053] To address the multiple heat-generating nodes that are spatially isolated within the lower half of the casing 1, the second cooling circuit adopts a parallel architecture. A water inlet channel 9 is provided at the main fluid inlet of the second cooling circuit. This water inlet channel 9 is built into the side wall of the casing 1 to receive the initial low-temperature cooling water introduced from the third interface 19.

[0054] The inlet water distribution chamber 9 is internally connected to several fixed throttling orifices 901. After a uniform cold source pumped in through an external pipeline establishes static pressure in the inlet water distribution chamber 9, it is passively distributed to two independent hydraulic branches, namely the back pressure chamber annular cooling jacket 7 and the spiral groove 8, according to the preset orifice size difference of each fixed throttling orifice 901.

[0055] The annular cooling jacket 7, serving as the first parallel branch, is a stationary, annular, closed cavity embedded in the inner wall of the housing 1. Its spatial position is precisely aligned with the axial plane of the back flange of the moving scroll 3, and a set physical gap is maintained between the inner wall of the jacket cavity and the back flange of the moving scroll 3, ensuring that the two remain in an absolutely non-contact state throughout the entire operation of the machine.

[0056] The cooling water, proportionally diverted here, flows circumferentially within the annular cooling jacket 7 of the back pressure chamber. This branch utilizes the interfacial heat conduction effect of the solid metal wall of the casing 1 to indirectly extract the relative motion frictional heat and latent heat of the gas accumulated in the back pressure chamber region. This structure creates a circumferentially uniform low-temperature operating environment for the back pressure chamber seals without introducing any internal fluid dynamic sealing components.

[0057] The spiral groove 8, serving as the second parallel branch, is directly machined onto the outer cylindrical surface of the main bearing housing 5. The inner wall of the housing 1 fits tightly with the outer wall of the main bearing housing 5, sealing the aforementioned open groove entity into a spiral flow channel with defined boundaries. Furthermore, static sealing rings are provided at both ends of the main bearing housing 5 to prevent coolant from leaking outwards along the axial direction.

[0058] Another cooling water path, distributed to this branch, enters from the spiral inlet and flows in a three-dimensional envelope around the main bearing housing 5 along the spiral direction. This independent flow path directly removes the mechanical frictional heat applied to the main bearing assembly by the high-speed rotation of the crankshaft. Through the above parallel flow-dividing structure, the two core heat-generating areas at the bottom of the entire machine each exclusively have access to the initial temperature cold source free from upstream waste heat pollution, eliminating the heat accumulation phenomenon inherent in traditional single-path series structures.

[0059] At the outlet ends of the annular cooling jacket 7 and the spiral groove 8 in the back pressure chamber, and before they merge into the main drain pipe 10, there are outlet flow stabilizing chambers 15 respectively. The internal cross-section of the outlet flow stabilizing chamber 15 is enlarged relative to its inlet cross-section, and the inner wall of the outlet flow stabilizing chamber 15 is provided with several staggered guide ribs 16 along the water flow direction.

[0060] The staggered guide ribs 16 are arranged in two rows, with the staggered guide ribs 16 in adjacent rows being staggered in the circumferential position, and the long axis of each staggered guide rib 16 is deflected at an angle relative to the main direction of the water flow to disrupt the uneven velocity distribution.

[0061] To ensure the fluid dynamic stability of the two parallel cooling branches when they converge at the tail end, a flow field equalization device is provided in the outlet section of the second cooling circuit. At the outlet ends of the annular cooling jacket 7 and the spiral groove 8 in the back pressure chamber, and before the main drain pipe 10 that flows into the bottom of the casing, a water outlet flow stabilizing chamber 15 is provided.

[0062] The outlet flow stabilization chamber 15 is configured as a transitional expansion chamber with abrupt cross-sectional changes. Its inlet cross-sectional dimensions are consistent with the outlet pipes of the upstream branches, while the cross-sectional area inside the chamber is significantly enlarged relative to the inlet cross-section. This spatial expansion structure forces the cooling water discharged at high speed from the narrow flow channel to experience a sudden drop in velocity at this point, converting most of the dynamic pressure into static pressure, thereby suppressing high-frequency pressure pulsations inside the pipeline.

[0063] The inner wall of the outlet flow stabilizing cavity 15 has several staggered flow guide ribs 16 protruding along the mainstream direction of the fluid. These flow guide ribs are divided into two rows within the cavity and are arranged in an alternating manner, with adjacent rows of flow guide ribs being staggered in the circumferential direction. In addition, the long axis of each flow guide rib is geometrically deflected at a certain angle relative to the mainstream direction of the cooling water.

[0064] After entering the expansion chamber, the cooling water carrying localized high temperatures and uneven velocity fields is forced to flow through and be guided by the staggered guide ribs 16. The fluid generates strong secondary vortices and microscopic disturbances between the ribs, effectively tearing apart the fluid boundary layer near the pipe wall. This physical stirring process rapidly smooths out the temperature and velocity gradients within the chamber's cross-section, ensuring that the two branch water flows have a highly consistent temperature and pressure state at their final confluence point, completely eliminating upstream flow distribution imbalances caused by fluid impact.

[0065] The core mechanism by which the aforementioned flow field homogenization device completely eliminates upstream flow distribution imbalance lies in the absolute physical isolation of the fluid dynamic pressure and static pressure conversion process and the forced dissipation of energy. When the cooling water in the two parallel branches flows through their respective narrow and complex heat exchange channels, it carries drastically different flow velocities, temperatures, and local dynamic pressures. If these two heterogeneous high-speed jets are allowed to directly and physically converge at the end of the pipe network, violent fluid shearing and momentum collisions will inevitably occur. This disordered fluid impact will instantly generate high-frequency transient back pressure waves at the confluence point. Once these back pressure waves are transmitted back along the incompressible liquid medium to the inlet water distribution chamber 9 of the entire unit, they will directly disrupt the initial static water pressure balance established by the fixed throttling orifice, causing the actual flow rate entering each branch to deviate from the initial design value.

[0066] To fundamentally sever the reverse backlash path of the aforementioned backpressure wave, the effluent stabilizing cavity 15 is configured in spatial topology as a transitional expansion domain with abrupt cross-section changes. Once the high-speed water flow discharged from the narrow channel enters this expansion cavity, its physical flow boundary instantly loses its original constraint, resulting in a step-like expansion of the fluid cross-sectional area. According to the fluid dynamics continuity equation and Bernoulli's principle, this spatial abrupt expansion structure forces a precipitous decrease in the absolute velocity of the water flow. The large amount of dynamic pressure carried by the fluid itself is forcibly stripped away in this expansion section and converted into stable static pressure, thereby absorbing the high-frequency pressure pulsations at the confluence front end on-site and constructing a hydraulic buffer barrier that blocks the upward transmission of downstream pressure disturbances.

[0067] Meanwhile, while simple spatial expansion can reduce velocity, it easily induces large-scale fluid detachment and disordered stagnation zones at the cavity edges, leading to new flow field instability. To address this, staggered guide ribs 16 arranged on the inner wall of the outlet flow stabilization cavity 15 actively intervene in the micro-momentum of the fluid. These metal ribs, arranged in a staggered pattern along the circumference and with specific deflection angles, strongly physically cut and reshape the flow direction of the incoming heterogeneous water flow. As the water flows over the rib array, it is forced to generate high-frequency secondary micro-vortices, completely shattering its residual chaotic kinetic energy and fluid impact force, which are then dissipated internally by the fluid's own viscous friction.

[0068] Through the dual modulation of spatial expansion deceleration and staggered fin forced stirring, the two branch water flows, originally carrying different thermodynamic and kinetic characteristics, have their internal velocity gradients and pressure spikes completely smoothed out before reaching the final physical confluence point at the bottom of the casing 1. The two water flows ultimately merge smoothly into the main drain pipe 10 in a highly consistent, homogeneous, low-speed, and purely static pressure state. This structure completely eliminates the water hammer effect and momentum collision at the tail-end fluid confluence without introducing any active mechanical pressure-regulating valves. The tail-end confluence point continuously maintains an absolutely stable back pressure boundary condition, thereby ensuring that the upstream inlet diversion chamber can always maintain its set branch diversion ratio accurately and persistently, relying on a constant and undisturbed system pressure difference.

[0069] The casing 1 has a thermosensitive solid throttling cross-loop compensation microchannel 13 inside its wall. The thermosensitive solid throttling cross-loop compensation microchannel 13 connects the area near the inlet of the first cooling circuit with the inlet water distribution chamber 9 of the second cooling circuit. A bimetallic throttling insert 14 is embedded inside the thermosensitive solid throttling cross-loop compensation microchannel 13. Under normal operating temperature, the bimetallic throttling insert 14 remains bent to block the thermosensitive solid throttling cross-loop compensation microchannel 13. When the temperature in the area near the inlet of the first cooling circuit rises abnormally, the bimetallic throttling insert 14 is heated and bends in the opposite direction to open the thermosensitive solid throttling cross-loop compensation microchannel 13, allowing the cooling water to perform cross-loop compensation.

[0070] To give this dual-physical-isolation water system the ability to self-rescue under extreme conditions, a heat-sensitive solid throttling cross-loop compensation microchannel 13 is concealed within the solid wall of the casing 1. One end of this microchannel is located on the inner wall of the casing 1 near the inlet of the first cooling circuit, while the other end is directly connected to the inlet water distribution chamber 9 of the second cooling circuit.

[0071] Deep within the cavity of the thermosensitive solid-state throttling cross-loop compensation microchannel 13, a set of bimetallic throttling inserts 14 are interference-fitted. These inserts are composed of two tightly rolled composite metal sheets with significantly different coefficients of thermal expansion. Within the unit's set normal operating temperature range, the bimetallic throttling inserts 13 maintain a specific bending shape due to preset initial internal stress. Their raised surfaces tightly seal the flow cross-section of the thermosensitive solid-state throttling cross-loop compensation microchannel 13, ensuring that the first and second cooling circuits remain absolutely disconnected in the liquid path.

[0072] When the central water inlet area of ​​the first cooling circuit encounters abnormally high temperatures, the excessive heat flow is rapidly conducted through the metal substrate of the casing 1 to the interior of the microchannels. The bimetallic strip throttling insert 14, activated by heat, generates a strong internal bending moment due to the asymmetry of thermal expansion between its two metal layers. This thermomechanical force directly drives the bimetallic strip to overcome the initial preload and bend and flip in the opposite direction, instantly opening the previously closed microchannel cross-section and establishing an emergency drainage channel spanning both major circuits.

[0073] It should be noted that the bimetallic throttling insert 14 is not a homogeneous entity of a single material, but a laminated structure formed by high-pressure rolling of two thin metal plates with significantly different coefficients of thermal expansion (such as a high-expansion-coefficient manganese-nickel-copper alloy layer and a low-expansion-coefficient Invar alloy layer). In cross-sectional view, there is no gap between the two metal substrates, exhibiting a metallurgically dense bond. Under normal conditions without extreme high-temperature stimulation, the insert as a whole presents as a pre-stressed, arched (or dome-shaped) curved sheet. Specifically, it has two relatively straight fixed ends and a highly convex outward-curving arc-shaped belly (convex surface). The high-expansion-coefficient alloy layer is located on the outer side of the convex surface of the arc-shaped belly, and the low-expansion-coefficient alloy layer is located on the inner side of the concave surface.

[0074] Secondly, the internal aperture of the thermosensitive solid throttling cross-loop compensation microchannel 13 is not of equal width at the top and bottom, but rather has a protruding annular throttling shoulder (equivalent to a valve seat) in the middle section. During assembly, the two straight ends of the bimetallic throttling insert 14 are interference-fitted into the pre-set mounting grooves on the inner wall of the microchannel, preventing it from undergoing overall displacement within the cavity. Under its own pre-tightening bending moment, the raised arc-shaped convex surface of the insert firmly abuts against and tightly covers the flow hole of the annular throttling shoulder. At this point, the convex surface and the shoulder form a physical hard seal through surface contact, completely cutting off the upstream and downstream fluid channels of the microchannel.

[0075] When extreme heat is applied, heat is conducted to the insert, causing the outer high-expansion layer to stretch dramatically, while the inner low-expansion layer remains almost unchanged. This asymmetric strain within the material instantly transforms into a massive internal bending moment. When the temperature crosses a critical point, the insert's curved belly undergoes a sudden, reverse flip, much like pressing down on the bottom of a convex plastic bottle. The previously raised convex surface instantly caves in, becoming concave. This reverse deformation directly forces the insert's central portion to detach from the annular throttling shoulder, instantly creating a crescent-shaped or semi-annular flow gap within the microchannel, thus achieving purely physical cross-loop leakage.

[0076] When the entire machine is operating under standard design conditions, the first and second cooling circuits maintain a completely decoupled dual-line liquid circulation through their respective independent external physical interfaces. The high-density heat flow generated in the core compression zone is forcibly constricted by the thermal isolation structure and precisely guided into the contoured, gradually expanding spiral water channel 6 inside the stationary vortex disk 2. As a temperature gradient is established within the solid substrate, the non-uniform thermal stress generated at the root of the vortex teeth is smoothly absorbed by the pre-set stress concentration release groove 12 in the form of local micro-elastic deformation. At the same time, the second cooling circuit located below steadily draws in initial-temperature water according to the resistance ratio set by the fixed throttling orifice 901, suppressing the mechanical friction heat of the main bearing and the latent heat of the gas in the back pressure chamber, respectively.

[0077] When the water supply end of the first cooling circuit encounters insufficient liquid supply or a sudden overload and extreme heat condition of the whole machine, the temperature of the solid substrate near the central exhaust area will exceed the normal design threshold. At this time, the abnormally accumulated high-intensity heat is rapidly conducted to the outside through the metal solid of the casing 1, directly reaching the heat-sensitive solid throttling cross-loop compensation microchannel 13 which is in a closed state.

[0078] The bimetallic throttling insert 14, which bears the heat, rapidly generates a huge bending moment and undergoes reverse bending deformation due to the unequal thermal expansion of the two layers of materials, instantly releasing the physical blockage of the microchannel. Since the outlet flow stabilizing chamber at the end of the second cooling circuit smooths out pipe network fluctuations, the upstream inlet flow chamber 9 maintains a consistently high static water pressure. Relying on the natural pressure difference established between the two circuits at this point, the low-temperature cold water in the inlet flow chamber 9 flows smoothly into the opened compensation microchannel, crossing the circuit boundary and directly injecting into the high-temperature critical area of ​​the first cooling circuit, implementing forced liquid cooling.

[0079] With the continuous injection of cross-loop compensating cooling water, the extreme heat load in the central exhaust zone is rapidly dissipated. Once the solid substrate temperature in this localized area is suppressed and returns to a safe range, the thermal stress induced by the bimetallic throttling insert 14 dissipates. Thanks to the elastic recovery properties of the bimetallic material itself, the insert automatically reverses and springs back to tightly adhere to the inner wall of the microchannel, completely severing the cross-water communication. The entire cooling system then seamlessly switches back to the normal mode of independent operation of the two loops.

[0080] The aforementioned multi-condition operation fully demonstrates the deep synergy of the entire unit in terms of solid-state heat transfer guidance, precise liquid heat carrying, and adaptive response to abnormal thermal conditions. Through spatially independent zoned direct cooling, physical thermal path bridging constraints, combined with stress pre-release and cross-loop passive venting in the mechanical dimension, this invention thoroughly internalizes complex thermal management logic into the mechanical body structure. This architecture avoids reliance on fragile electronic thermistor components and servo-driven valves, relying on a purely physical instinctive response mechanism to construct a highly reliable comprehensive thermal defense system for water-cooled oil-free scroll compressors.

[0081] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A water-cooled oil-free scroll air compressor with a dual inlet and outlet water structure, comprising a housing (1), a stationary scroll (2) disposed within the housing (1), a moving scroll (3) coupled to the stationary scroll (2), and a main bearing housing (5) for supporting a crankshaft (4), characterized in that, The housing (1) contains a first cooling circuit and a second cooling circuit that are independent of each other. The first cooling circuit is located inside the stationary vortex disk (2) and includes a contoured spiral water channel (6). The inlet of the contoured spiral water channel (6) is located in the central exhaust area of ​​the stationary vortex disk (2), and the outlet is located in the outer ring intake area of ​​the stationary vortex disk (2). The second cooling circuit is located inside the housing (1) and adopts a parallel structure, including a back pressure chamber annular cooling jacket (7) and a spiral groove (8). The back pressure chamber annular cooling jacket (7) is located on the inner wall of the housing (1) at the position corresponding to the back flange of the moving vortex disk (3). The spiral groove (8) is opened on the outer wall of the main bearing seat (5).

2. The water-cooled oil-free scroll air compressor with a dual inlet and outlet water structure according to claim 1, characterized in that, The planar projection outline of the contoured spiral channel (6) maintains a geometrical contouring relationship with the vortex tooth profile of the static vortex disk (2). The cross-sectional area of ​​the contoured spiral channel (6) gradually expands along the water flow direction, that is, the cross-sectional area of ​​the inlet end is smaller than that of the outlet end.

3. A water-cooled oil-free scroll air compressor with a dual-inlet / outlet water structure according to claim 1, characterized in that, The second cooling circuit also includes an inlet water distribution chamber (9) and a main drain pipe (10). The inlet water distribution chamber (9) is located on the side wall of the housing (1) and has a fixed throttling hole (901) inside. After the external cooling water enters the inlet water distribution chamber (9), it is distributed to the annular cooling jacket (7) and the spiral groove (8) of the back pressure chamber according to the ratio through the fixed throttling hole (901), and then flows into the main drain pipe (10).

4. A water-cooled oil-free scroll air compressor with a dual inlet and outlet water structure according to claim 1, characterized in that, The interior of the static vortex disk (2) is also provided with a thermal isolation structure. The thermal isolation structure is an annular narrow groove (11) located between the contoured spiral water channel (6) and the mounting stop of the static vortex disk (2). The annular narrow groove (11) is filled with a non-metallic material with low thermal conductivity to block the radial conduction of heat from the central exhaust area of ​​the static vortex disk (2) to the casing (1).

5. A water-cooled oil-free scroll air compressor with a dual inlet and outlet water structure according to claim 2, characterized in that, The bottom of the static vortex disk (2) is provided with multiple stress concentration relief grooves (12). The multiple stress concentration relief grooves (12) extend radially along the side wall of the contoured spiral channel (6). The width and depth of the stress concentration relief grooves (12) gradually narrow from the center to the outer ring of the static vortex disk (2), and have a spatial geometric correspondence with the gradually expanding cross-sectional area of ​​the contoured spiral channel (6), so that the high thermal stress concentration area obtains the maximum stress relief cross section.

6. A water-cooled oil-free scroll air compressor with a dual-inlet / outlet water structure according to claim 3, characterized in that, The casing (1) is provided with a thermosensitive solid throttling cross-loop compensation microchannel (13) in its wall. The thermosensitive solid throttling cross-loop compensation microchannel (13) connects the area near the water inlet of the first cooling circuit with the water inlet distribution chamber (9) of the second cooling circuit. A bimetallic strip throttling insert (14) is embedded inside the thermosensitive solid throttling cross-loop compensation microchannel (13). Under normal operating temperature, the bimetallic strip throttling insert (14) remains bent to block the thermosensitive solid throttling cross-loop compensation microchannel (13). When the temperature in the area near the water inlet of the first cooling circuit rises abnormally, the bimetallic strip throttling insert (14) is heated and bends in the opposite direction to open the thermosensitive solid throttling cross-loop compensation microchannel (13), allowing the cooling water to perform cross-loop compensation.

7. A water-cooled oil-free scroll air compressor with a dual inlet and outlet water structure according to claim 3, characterized in that, At the respective water outlet ends of the back pressure cavity annular cooling jacket (7) and spiral groove (8), and before they merge into the main drainage pipe (10), water outlet stabilizing chambers (15) are provided respectively. The internal cross-section of the water outlet stabilizing chamber (15) is enlarged relative to its inlet cross-section, and the inner wall of the water outlet stabilizing chamber (15) is provided with several staggered guide ribs (16) along the water flow direction.

8. A water-cooled oil-free scroll air compressor with a dual inlet and outlet water structure according to claim 7, characterized in that, The staggered guide ribs (16) are arranged in two staggered rows. The staggered guide ribs (16) between adjacent rows are staggered in the circumferential position, and the long axis of each staggered guide rib (16) is deflected at an angle relative to the main direction of the water flow to disrupt the uneven velocity distribution.

9. A water-cooled oil-free scroll air compressor with a dual inlet and outlet water structure according to claim 1, characterized in that, The back pressure cavity annular cooling jacket (7) is a stationary annular cavity structure fixedly installed on the inner wall of the housing (1). The back pressure cavity annular cooling jacket (7) and the back flange of the moving scroll (3) are kept apart and do not directly contact each other. The back pressure cavity area is indirectly cooled by heat conduction through the metal wall of the housing (1).

10. A water-cooled oil-free scroll air compressor with a dual-inlet / outlet water structure according to claim 1, characterized in that, The water-cooled oil-free scroll air compressor has four independent cooling water inlets: The first interface (17) is the water inlet pipe of the first cooling circuit, located in the center area of ​​the top of the static vortex plate (2); The second interface (18) is the outlet pipe of the first cooling circuit, located in the outer ring area on the side of the static vortex plate (2); The third interface (19) is the water inlet pipe of the second cooling circuit, located on the side wall of the casing (1); The fourth interface (20) is the water outlet pipe of the second cooling circuit, located at the bottom of the casing (1).

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