SPIRAL COMPRESSOR WITH DIRECT OIL RETURN FROM AN OIL SEPARATOR TO A COMPRESSION SECTION

Description

[0001] The invention relates to a spiral compressor for compressing a fluid with a compression section, which has an inlet of the compression section for drawing the fluid into the compression section, an outlet of the compression section for expelling the compressed fluid from the compression section, a stationary disk with a stationary spiral, and an orbiting disk with an orbiting spiral.

[0002] Scroll compressors are used, for example, as compressors in air conditioning systems, especially in automotive air conditioning systems. They are also used as heat pumps. Compared to other types of compressors, they are characterized by particularly smooth, low-vibration, and quiet operation.

[0003] The compression section forms the core of the scroll compressor. As the orbiting scroll rotates relative to the stationary scroll, the fluid—especially a gas or gas mixture—is compressed. For this purpose, the orbiting scroll and the stationary scroll are nested within each other, forming compression chambers for the fluid between them. Relative to the stationary scroll, each compression chamber, along with the fluid it contains, moves from an outer region of the stationary scroll to its center. During this movement, the space available for the fluid decreases, and the fluid is compressed.

[0004] During operation, a maximum fluid pressure is reached at the outlet of the compression section. The fluid enters the compression section at a certain intake pressure and is expelled at a significantly higher outlet pressure.

[0005] The fluid, which is increasingly compressed between the orbiting disk and the stationary disk, forces the orbiting disk and the stationary disk apart. This creates a lifting force on the orbiting disk. The magnitude of this lifting force depends primarily on the intake pressure, the outlet pressure, and the geometry of the compression section. Typically, a change in the outlet pressure has a more significant effect on the contact pressure than a change in the intake pressure.

[0006] To achieve high compression, the compression chambers formed by the meshing of the stationary disc and the orbiting disc, which are shifted toward the center, must be sufficiently sealed. To ensure that the orbiting disc is pressed firmly and sealingly against the stationary disc and that no fluid escapes from the compression section, the orbiting disc is subjected to contact pressure on its rear side opposite the stationary disc. For this purpose, a contact pressure chamber is provided on the rear side of the orbiting disc. The contact pressure pushes the orbiting disc toward the stationary disc with a contact force.

[0007] The engagement of the orbiting scroll with the stationary disk and the engagement of the stationary scroll with the orbiting disk create friction during operation. Electrically driven scroll compressors typically operate in a speed range of 500 to 12,000 rpm. High friction results in reduced efficiency.

[0008] Oil is fed into the contact pressure chamber to lubricate the orbiting disc. Furthermore, an oil supply line can be provided from the contact pressure chamber through the orbiting disc. Through the oil supply line, oil from the contact pressure chamber can flow between the stationary disc and the orbiting disc.

[0009] The fluid discharged by the scroll compressor should contain as little oil as possible. An excessive amount of oil in the discharged fluid can impair the efficiency of downstream components to which the discharged fluid flows. For example, the efficiency of a refrigerant circuit can deteriorate with increasing oil admixture.

[0010] Typically, in a refrigerant circuit, the scroll compressor is the only component within the circuit itself that requires oil for the lubrication of mechanically stressed parts. A refrigeration circuit can generally operate in different states. The efficiency of the refrigeration circuit depends significantly on its operating state. For example, an excessive amount of oil can cause surfaces within heat exchangers to become oily. This reduces the heat transfer coefficient in the respective heat exchanger. Consequently, the efficiencies of the evaporator and condenser decrease. As a result, the entire refrigerant circuit must be operated at a higher pressure ratio to achieve the required cooling capacity.An excessive amount of oil therefore reduces the overall efficiency and increases the stress on the mechanical components within the spiral compressor due to the increased pressure ratio.

[0011] Therefore, after the compression section, the compressed fluid is passed through an oil separator. The oil separator at least partially separates the oil from the compressed fluid. The separated oil is then returned to the pressure chamber via a (second) oil return line.

[0012] During operation of the scroll compressor, the oil in the contact pressure chamber is subjected to contact pressure. An orifice of the oil supply line is positioned in the central region of a compressor channel of the orbiting disc, which is formed by the orbiting scroll on the orbiting disc. Due to this positioning and a continuous mass flow of a mixture of oil and refrigerant coming from a high-pressure side, a contact pressure at a medium pressure level is established in the contact pressure chamber. The contact pressure presses the orbiting disc with a contact force towards the stationary disc. Positioning in the central region is crucial for ensuring that the desired and sufficiently high contact pressure is achieved. The contact pressure is variable and dependent on the operating pressures.This ensures a seal between the stationary disk and the orbiting disk at all operating points and keeps friction as low as possible.

[0013] Due to this positioning of the oil supply line outlet, the radially outer areas between the stationary and orbiting discs are not optimally supplied with oil. This results in increased friction, reduced efficiency, and potentially a shorter service life for the spiral compressor.

[0014] The object of the present invention is to create a spiral compressor that enables more efficient operation and has higher reliability.

[0015] The above task is solved by a spiral compressor for compressing a fluid.

[0016] The spiral compressor for compressing a fluid includes: a compression section having a compression section inlet for sucking the fluid into the compression section, a compression section outlet for expelling the compressed fluid from the compression section, a stationary disk with a stationary scroll, and an orbiting disk with an orbiting scroll, wherein the orbiting disk is orbitable relative to the stationary disk along a compression direction to convey the fluid from the compression section inlet to the compression section outlet, thereby compressing it; and an oil separator for separating oil from the compressed fluid;wherein the scroll compressor has a direct oil return for the direct return of oil from the oil separator to the compression section, wherein the direct oil return has at least one outlet opening, wherein the direct oil return comprises a first flow valve, wherein the direct oil return comprises an exhaust chamber arranged between the first flow valve and the outlet opening of the direct oil return, and wherein the scroll compressor has a fluid return for the return of fluid from the exhaust chamber to the compression section.

[0017] Direct oil recirculation continuously returns oil from the oil separator to the compression section during operation. This reduces friction in the compression section, enabling more efficient operation of the scroll compressor. Furthermore, it reduces wear in the compression section, increasing the reliability and service life of the scroll compressor.

[0018] During operation, the oil separator is (at least substantially) subjected to the outlet pressure. The invention utilizes a difference between the pressure in the oil separator and the pressure of the fluid at the outlet opening to return the oil from the oil separator directly and selectively to the compression section. A crucial advantage is that the oil flow through direct oil return is driven by a pressure ratio of the outlet pressure to the intake pressure. The amount of oil returned depends significantly on this pressure ratio. For example, at an intake pressure of 3 bar and an outlet pressure of 15 bar at a speed of 600 min⁻¹, this amount is the same as at an intake pressure of 3 bar, an outlet pressure of 15 bar, but a speed of 8500 min⁻¹.

[0019] The amount of oil returned through the direct oil return is (at least essentially) independent of the speed of the scroll compressor and (at least essentially) independent of the exact discharge pressure. Even at low speeds, the direct oil return returns a sufficient amount of oil to the compression section. Direct oil return is therefore suitable for lubricating the compression section under a wide range of scroll compressor load conditions. It particularly improves lubrication at low speeds.

[0020] Furthermore, the direct oil return system functions independently of the clamping pressure. Even if the clamping pressure drops, the direct oil return system continues to return oil to the compression section as long as the outlet pressure remains sufficiently high.

[0021] In addition, the oil is retained better in the scroll compressor. The inlet area no longer needs to be supplied with oil that creeps from a contact pressure chamber into the compression section or is led through an external part of a refrigerant circuit to the inlet of the compression unit. The external part of the refrigerant circuit refers to those areas of the refrigerant circuit that are located outside the scroll compressor. The fluid behind the oil separator contains less oil. Less oil is led through the external part of the refrigerant circuit. Typically, a higher proportion of oil in the fluid in an external part of the refrigerant circuit results in poorer thermodynamic properties of the refrigerant-oil mixture. The proposed direct oil return significantly reduces the oil circulation ratio (OCR) of the refrigerant circuit.Direct oil supply delivers the oil precisely to an inlet area of ​​the compression unit. This improves the efficiency of the refrigerant circuit.

[0022] Especially at low speeds, conventional spiral compressors have an increased risk of oil unintentionally remaining in the external part of the refrigerant circuit due to the low mass flow of the refrigerant through the external part of the refrigerant circuit.

[0023] Conversely, the proportion of oil available for lubrication within the scroll compressor, and especially within the compression section, increases. Active, direct oil recirculation reduces the total amount of oil required for the operation of the scroll compressor. This lowers costs and reduces the weight of the refrigerant circuit. As a result, for example, the efficiency of a vehicle equipped with a scroll compressor increases.

[0024] The outlet of the compression unit is located at least substantially at the center of the stationary disk. In particular, the outlet of the compression unit can be located exactly at the center of the stationary disk.

[0025] The stationary spiral forms a spiral compressor channel (the stationary disk) that extends from an outer end of the stationary spiral to an inner end. The inner end of the stationary spiral is located at the center of the stationary spiral. It is situated at an outlet opening of the stationary disk. The outlet of the compression section encompasses this outlet opening. In particular, this outlet opening can form the outlet of the compression section.

[0026] The stationary spiral can be arranged on a stationary base surface of the stationary disk. The stationary spiral can be formed from a wall that extends parallel to a central axis of the stationary disk from the stationary base surface away from the stationary base surface. Preferably, an end face of the stationary spiral facing away from the stationary base surface along this central axis is flat and parallel to the stationary base surface.

[0027] The outlet opening may comprise a hole in the stationary base. In particular, the outlet opening may be formed as a hole in the stationary base.

[0028] Similarly, the orbiting spiral forms a spiral compressor channel of the orbiting disk, extending from an outer end of the orbiting spiral to an inner end of the orbiting spiral. The term "compressor channel" without further specification refers in this disclosure and in the claims only to the compressor channel of the stationary disk, unless explicitly stated otherwise or unless the context necessarily implies otherwise.

[0029] The orbiting spiral can be arranged on an orbiting base surface of the orbiting disk. The orbiting spiral can be formed from a wall extending away from the orbiting base surface, parallel to a central axis of the orbiting disk. Preferably, an end face of the orbiting spiral, facing away from the orbiting base surface along this central axis (of the orbiting disk), is flat and parallel to the orbiting base surface. The orbiting base surface can be parallel to the stationary base surface.

[0030] The stationary spiral and the orbiting spiral can each have exactly one spiral arm.

[0031] The spiral compressor features an orbiting mechanism for orbiting the orbiting disk relative to the stationary disk. During orbiting, the orbiting disk is displaced eccentrically relative to the stationary disk along a path that is at least substantially circular. Preferably, the central axis of the orbiting disk is moved circularly around the central axis of the stationary disk. The central axis of the stationary disk can be perpendicular to the stationary disk's base. It can extend through a center of the stationary disk and / or a center of the stationary spiral. In particular, the center of the stationary spiral can be the center of the stationary disk, and vice versa.

[0032] During operation (compressor operation), at least one compression chamber is formed between the orbiting scroll and the stationary scroll. The drawn-in fluid is enclosed in the compression chamber, compressed there, moved toward the outlet opening of the stationary disk, and finally pressed into this outlet opening.

[0033] An intake section of the compressor channel comprises all areas of the compressor channel that are at least temporarily in direct fluid contact with the inlet of the compression section when the orbiting disk orbits relative to the stationary disk along the compression direction. An outlet section of the compressor channel comprises all areas of the compressor channel that are at least temporarily in direct fluid contact with the outlet of the compression section when the orbiting disk orbits relative to the stationary disk along the compression direction. A middle section of the compressor channel comprises all areas of the compressor channel that cannot be in direct fluid contact with either the inlet or the outlet of the compression section. These definitions apply to both the compressor channel of the stationary disk and the compressor channel of the orbiting disk.

[0034] For the purposes of this application, an innermost turn or first turn of a respective spiral refers to a region of that spiral which extends from its inner end to the point where it has once encircled its center.

[0035] The inner end of the stationary spiral is assigned a position angle of 0°. This position angle increases continuously along the spiral's length to its outer end. The spiral angle of the stationary spiral is defined by its outer end. Therefore, the spiral angle corresponds to the largest position angle of the stationary spiral.

[0036] This is explained using the example of a stationary spiral with two turns: The first turn of the stationary spiral begins at the inner end of the stationary spiral at a position angle of 0° and ends at a position angle of 360°. The second and outermost turn begins at a position angle of 360° and ends at a spiral angle of 720° with the outer end of the stationary spiral.

[0037] Position angles are defined accordingly within the compressor channel. An outer end of the spiral compressor channel is defined by an inlet opening of the compressor channel, which is formed between the outer end of the stationary spiral and an inner beginning of the outermost turn of the stationary spiral.

[0038] For the purposes of this application, an outer side of a region of a respective spiral is a side of this spiral region facing away from the spiral center in the radial direction. Accordingly, an inner side of this spiral region is a side of this spiral region facing toward the spiral center in the radial direction.

[0039] The compression section can form internally guided compression chambers and externally guided compression chambers. An internally guided compression chamber is formed and runs along the outside of the stationary spiral. An externally guided compression chamber is formed and runs along the outside of the stationary spiral.

[0040] It should be emphasized here that the definitions regarding the compressor channel are independent of the definition of the compression chamber. In particular, the compression chamber does not need to be completely within the compressor channel of the stationary disk at all times. For example, the compression chamber can be formed when the outer end of the orbiting spiral comes into contact with the outer surface of the outermost turn of the stationary spiral. This seal closes and seals an internally guided compression chamber. The newly formed, internally guided compression chamber may still be (partially) outside the compressor channel of the stationary disk at this point. Conversely, an externally guided compression chamber is closed when an outer surface of the orbiting spiral comes into contact with the outer end of the stationary spiral.The newly formed, externally guided compression chamber is already completely within the compressor channel at this point. It is guided along the outside of the compressor channel. In other words, the outside of the compressor channel is formed by the inside of the stationary spiral.

[0041] During operation, an intake pressure is present at the inlet of the compression section, and an outlet pressure is present at the outlet of the compression section. Preferably, the intake pressure during operation is in the range of 1 bar to 7 bar. Alternatively or additionally, the outlet pressure during operation is in the range of 8 bar to 32 bar. The exact intake and outlet pressures may vary depending on the fluid used and the specific operating conditions.

[0042] The intake and outlet pressures during operation can be determined by a system connected to the scroll compressor, through which the fluid compressed in the scroll compressor flows. Such a system could, for example, be a heat exchanger in an air conditioning system.

[0043] The maximum outlet pressure of a scroll compressor is determined by the geometry of the compression section and the respective intake pressure. Furthermore, the dead volume of the outlet opening of the stationary disk (outlet bore) can influence the maximum outlet pressure. The higher the intake pressure, the higher the maximum outlet pressure. For a given intake pressure, the maximum outlet pressure is determined by the compression of the fluid achievable in the compression section due to its geometry, using known fluid equations, such as the ideal gas law or the van der Waals equation. The (actual) outlet pressure is generally lower than the maximum outlet pressure.

[0044] The inlet of the compression section can comprise several sub-sections. In particular, the inlet can have a first inlet sub-section through which the radially inner compression chambers are supplied with fluid, and a second inlet sub-section through which the radially outer compression chambers are supplied with fluid. The sub-sections can be spatially separated from each other, for example, in a radially outer region of the compression section on two opposite sides.

[0045] Direct oil return serves to return oil directly from the oil separator to the compression section. The direct oil return system extends directly from the oil separator to the compression section.

[0046] During operation, oil is forced into the direct oil return by the pressure from the oil separator. This oil flows through the direct oil return along one oil flow direction and exits the direct oil return opening into the compression section. The oil thus returned serves to lubricate the compression section.

[0047] In a preferred embodiment of the invention, the outlet opening (of the direct oil return) is located in an inlet area of ​​the compression section, which during operation is at least temporarily in direct fluid communication with the inlet of the compression section. This ensures particularly good lubrication even in the radially outer regions of the orbiting scroll and the stationary scroll.

[0048] Depending on the precise positioning of the orifice, it is possible, for example, that the orifice is temporarily swept over and obscured by the orbiting spiral during operation. At this point, the orifice is not in direct fluid contact with the inlet. It is also possible that, during a complete rotation of the orbiting disk, the orifice is in direct fluid contact with the inlet in a first period, swept over by the orbiting spiral in a second period, connected to a compression chamber in a third period, and swept over by the orbiting spiral again in a fourth period.

[0049] In a particularly preferred embodiment, the mouth opening is never swept over by the compression chamber (or any of the multiple compression chambers).

[0050] Alternatively or additionally, the muzzle opening is preferably swept over exactly once by the orbiting spiral during a complete revolution of the orbiting spiral.

[0051] The orifice of the direct oil return is preferably located in the stationary pulley. This reduces complexity and simplifies the manufacture of the direct oil return. In particular, the orifice can be located entirely in the stationary base. Alternatively, the orifice can be located entirely or partially in the inside or outside of the stationary scroll. Such variants are more difficult to manufacture. However, they can further improve lubrication on the inside or outside of the stationary scroll.

[0052] In a particularly preferred embodiment, the outlet opening of the direct oil return is arranged in the intake region of the compressor channel (of the stationary scroll), which during operation is at least temporarily in direct fluid communication with the inlet of the compression section, and / or is arranged outside the compressor channel. If the outlet opening is arranged at the outer end of the compressor channel, a first portion of the outlet opening can be arranged in the compressor channel, and a second portion of the outlet opening can be arranged outside the compressor channel.

[0053] According to another aspect, the outlet opening for the direct oil return is preferably arranged at a position angle in the range of γ - 30° and γ + 30°, where γ is a position angle of the outer end of the compressor channel. In this case, the outlet opening can also be arranged at a radial distance RM,1 from the center of the stationary disk, where RM,1 lies in a range between (RI (γ) - BK ) and RI (γ), where RI (γ) is a radial distance of the inner surface of the stationary spiral at the outer end of the compressor channel (i.e., at the outer end of the stationary spiral), and BK is a width of the compressor channel in the radial direction at the outer end of the compressor channel. Thus, in this case, the outlet opening is located near the outer end (upstream end) of the compressor channel. The outlet opening is then swept at least once during one revolution by the end face of the orbiting spiral.This ensures particularly good distribution of the oil exiting the orifice. Specifically, RM,1 can lie within a range between (RI (γ) - BK / 2) and RI (γ). An orifice designed in this way contributes significantly to lubrication in the area of ​​externally routed compression chambers.

[0054] Alternatively, the outlet opening for direct oil return is preferably located outside the stationary spiral and at a position angle in the range of θ - 30° to θ + 30°, where θ = γ + 180°. In this case, the outlet opening can also be located at a radial distance RM,2 from the center of the stationary disk, where RM,2 lies in the range of RA (θ - 360°) to RA (θ - 360°) + BK, where RA (θ - 360°) is a radial distance from the outer surface of the stationary spiral at the position angle θ - 360°. In this embodiment, the outlet opening is thus located outside the stationary spiral and, relative to the center of the stationary spiral, at a position opposite the outer end of the compressor channel. This results in particularly good distribution of the oil exiting the outlet opening. In particular, RM,2 can lie in a range between RA (θ - 360°) and RA (θ - 360°) + BK / 2.A muzzle opening designed in this way contributes particularly well to lubrication in the area of ​​the internally guided compression chambers.

[0055] Particularly preferred are several openings, wherein at least one of the several openings is configured according to one of the embodiments described in the penultimate aspect, and at least one of the several openings is configured according to one of the embodiments described in the last aspect. The advantages apply accordingly.

[0056] According to the invention, the direct oil return system comprises a first flow valve. The first flow valve is preferably arranged (viewed along the flow direction of the oil in the direct oil return system) between a first oil inlet of the direct oil return system and the outlet opening. However, the first flow valve can also generally be arranged directly at the first oil inlet or at the outlet opening. In particular, the first flow valve can be formed by the first oil inlet and / or the second outlet opening itself. The first flow valve reduces the mass flow of the oil (optionally with dissolved fluid) that is returned by the direct oil return system.

[0057] The first flow valve is particularly preferably designed as a throttle valve.

[0058] In this application, a throttle valve is preferably understood to be an element that generates a pressure difference between the valve inlet and outlet. It can particularly preferably be an unregulated throttle valve. It can, for example, be an orifice or nozzle. This allows for simple, cost-effective, and reliable implementation.

[0059] The first flow control valve is designed to reduce the mass flow of oil (including any fluid dissolved therein) from the oil separator. In this way, a pressure in the direct oil return line downstream of the first flow control valve (for example, an intermediate pressure described below and / or an orifice pressure described below) can be easily influenced.

[0060] According to the invention, the direct oil return comprises the first flow control valve and a degassing chamber arranged (as seen along the intended flow direction of the oil in the direct oil return) between the first flow control valve and the outlet opening of the direct oil return. In other words, the degassing chamber is arranged downstream of the first flow control valve and upstream of the outlet opening.

[0061] The direct oil return continuously removes oil from the oil separator during operation and stores excess oil in the degassing chamber. The degassing chamber is located within the scroll compressor. By continuously removing the oil from the oil separator, for example, at or near the bottom of the oil separator, and actively storing the oil, the efficiency of the separation process is maximized. The amount of oil leaving the compressor and entering an external refrigerant circuit is minimized.

[0062] As mentioned previously, particularly at low speeds, the low refrigerant mass flow rate increases the risk of oil, expelled from the scroll compressor into the external refrigerant circuit, unintentionally remaining there. Even in such a case, the oil from the exhaust chamber ensures the continued oil supply to the scroll compressor until the system reaches equilibrium. When the operating point changes to a high-load point, the oil previously trapped in the external refrigerant circuit is carried back into the scroll compressor by the high refrigerant mass flow rate, collected, and temporarily stored within the compressor. This allows the system to self-adjust, absorbing or releasing oil as needed.

[0063] During operation, the oil separator is (at least substantially) subjected to the outlet pressure. This results in high solubility of the fluid in the liquid oil within the oil separator. The first flow control valve reduces the mass flow of the oil (along with any dissolved fluid) out of the oil separator. This helps to lower the intermediate pressure in the exhaust chamber compared to the outlet pressure. Consequently, the solubility of the fluid in the oil also decreases. Downstream of the first flow control valve, the oil may be supersaturated with fluid. In the exhaust chamber, the supersaturated fluid can separate (at least partially) from the oil in a controlled manner. This reduces the risk of uncontrolled, excessive bubble formation in the oil downstream of the exhaust chamber.When the supersaturated portion of the fluid is completely separated from the oil, the maximum amount of fluid in the oil is exactly the amount that can be dissolved in the oil under the given conditions at equilibrium (saturated portion of the fluid in the oil).

[0064] From the oil separator, a first fluid connection for direct oil return leads to the exhaust chamber. The first flow valve can be located in this first fluid connection. From the exhaust chamber, a second fluid connection for direct oil return leads to the outlet opening.

[0065] Preferably, the scroll compressor is configured such that (during operation) an intermediate pressure in the exhaust chamber is in a range of 0.2 bar to 6 bar above the intake pressure (of the compression section or the scroll compressor), most preferably in a range of 0.3 bar to 5 bar above the intake pressure. The exact intermediate pressure can be influenced, for example, by the first throttle valve and / or by a fluid return, which is described further below.

[0066] This ensures that sufficient oil exits the direct oil return port. It also ensures that no fluid flows through the direct oil return port against the oil flow direction. An excessively high pressure drop between the intermediate pressure and the intake pressure could cause too much oil to flow from the exhaust chamber into the compression section.

[0067] Alternatively or additionally, the spiral compressor is preferably configured so that the intermediate pressure in the exhaust chamber during operation is at least 106% of the intake pressure.

[0068] The absolute values ​​of the intake pressure can vary for different operating conditions, and the absolute values ​​of the intermediate pressure can vary for different operating conditions. The ratio between intermediate pressure and intake pressure can also vary for different operating conditions. However, the ratio should be at least 1.06 for all (proper) operating conditions.

[0069] Preferably, the degassing chamber has a volume in the range of 30 cm³ to 150 cm³, and most preferably in the range of 50 cm³ to 90 cm³. This ensures that the oil remains in the degassing chamber for a sufficiently long average time for at least a significant portion of the supersaturated fluid to evaporate. Furthermore, the intermediate chamber is so compact that it requires little space and can be easily integrated.

[0070] In a highly preferred development, the direct oil return comprises a second flow control valve, which is arranged downstream of the outgassing chamber (as viewed along the flow direction of the oil in the direct oil return). In particular, the second flow control valve can be arranged in the second fluid connection, i.e. downstream of the outgassing chamber and upstream of the outlet opening of the direct oil return. In particular, the second flow control valve can be designed as a throttle valve. As already defined above, the throttle valve can be, for example, an orifice or nozzle. It is possible for the second flow control valve to be formed integrally with the outlet opening and / or an oil inlet of the second fluid connection on the outgassing chamber. The second flow control valve serves to limit a mass flow of oil out of the outgassing chamber. This allows the outlet pressure of the oil at the outlet opening to be influenced in a simple and reliable manner.

[0071] If the direct oil return has multiple outlet openings, it preferentially branches downstream of the exhaust chamber (relative to the oil flow direction). This means only one intake chamber is needed for the multiple outlet openings. This simplifies the design and manufacturing of the scroll compressor and reduces its cost. It is also possible for several secondary fluid connections to branch directly from the exhaust chamber.

[0072] It is extremely advantageous if the direct oil return (or the second fluid connection) branches downstream of the second flow valve. This means that only one common second flow valve is needed for the multiple outlets of the same direct oil return system. This further reduces the design and manufacturing costs. Furthermore, the same outlet pressure is then present (at least essentially) at the multiple outlets.

[0073] Alternatively, different second flow control valves can be provided for different of the multiple muzzle openings. This allows the muzzle pressure to be set differently for different muzzle openings.

[0074] In a particularly preferred embodiment, the scroll compressor has a fluid recirculation system for fluid from the exhaust chamber to the compression section. This allows the fluid that was separated from the oil in the outlet chamber to be returned to the fluid circuit.

[0075] Most preferably, the fluid return opening is located in the compressor channel of the stationary disk. The opening can be formed, for example, as a hole in the stationary disk base. At least a portion of the fluid return can be formed in the stationary disk. This reduces complexity and manufacturing costs.

[0076] Most preferably, the fluid return port is located in the central region of the compressor channel (the stationary disk). This ensures that no fluid can flow out of the fluid return port upstream of the compression section inlet. At the same time, it is ensured that the fluid return port does not come into direct fluid communication with the outlet port of the stationary scroll. This ensures high efficiency and effectiveness of the scroll compressor.

[0077] The fluid return can include a check valve. The check valve prevents fluid from flowing from a compression chamber that passes over the fluid return outlet opening into the exhaust chamber. Alternatively or additionally, the fluid return can include a flow control valve. This makes it easier to set the intermediate pressure in the exhaust chamber higher than an average fluid pressure (in the compressor channel) at the fluid return outlet opening.

[0078] In another embodiment, fluid can flow (at least substantially) unhindered between the outgassing chamber and the orifice of the second fluid connection. This means that the second fluid return has neither a check valve nor a flow control valve. Then, the intermediate pressure in the intake chamber is particularly directly influenced by the time-averaged fluid pressure at the orifice of the fluid return.

[0079] According to another aspect, the fluid return outlet is most preferably arranged at a position in the compressor channel where the time average pressure of the fluid in the compressor channel during operation lies in a range of 104% to 170% of the intake pressure, or in a further development in a range of 105% to 150%.

[0080] If, in an idealized scenario, the mass flow rates of the recirculated oil and fluid are disregarded, the intermediate pressure in the exhaust chamber would be precisely the time-averaged pressure of the fluid at the fluid return outlet. In reality, due to the mass flow rates of the recirculated oil and fluid, the intermediate pressure during operation is higher than the time-averaged pressure of the fluid at the fluid return outlet. This pressure difference causes fluid from the exhaust chamber to flow through the fluid return into the compression section. The pressure difference is maintained by the supply of fresh oil from the oil separator into the exhaust chamber, along with the dissolved fluid. However, the intermediate pressure is significantly influenced by the time-averaged pressure of the fluid at the fluid return outlet.

[0081] The relationship between the time-averaged fluid pressure at the fluid return outlet and the intake pressure depends primarily on the geometry of the compression section and the precise position of the fluid return outlet within the compressor channel. Even under different operating conditions, this relationship remains essentially constant, given a fixed outlet position. However, the relationship can be precisely controlled by adjusting the position of the outlet. The described embodiment therefore represents a particularly simple, reliable, and versatile approach for selectively influencing the intermediate pressure.

[0082] The absolute values ​​of the intake pressure can differ for different operating conditions, and the absolute values ​​of this time-averaged pressure can also differ for different operating conditions. The ratio between the intake pressure and this time-averaged pressure of the fluid at the fluid return outlet can also vary for different operating conditions. However, this ratio should remain within the specified range for all (proper) operating conditions.

[0083] The described ratio adjustment ensures a favorable intermediate pressure in the outgassing chamber, for example, according to one of the advantageous embodiments described elsewhere. The intermediate pressure is high enough that sufficient oil flows from the outgassing chamber to the (at least one) outlet of the direct oil return, exits there, and enters the compression section. On the other hand, the intermediate pressure is low enough that an excessive amount of oil does not flow out of the outgassing chamber, and that at least a significant portion of the fluid dissolved in the oil supplied to the outgassing chamber separates from the oil in the outgassing chamber.

[0084] The ratio of the time-averaged pressure of the fluid (in the compressor channel) at the outlet to the intake pressure can be determined, for example, by calculating and / or measuring the pressure of the fluid in the compressor channel at the outlet position, averaged over one revolution, for a given intake pressure. Alternatively, the determination can be made by measuring and / or calculating the compression ratio of the fluid in the compressor channel at the fluid return outlet, averaged over one revolution.

[0085] Time periods (or ranges of rotation angles) in which the fluid return outlet is closed by the orbiting spiral can be disregarded for the calculation of the time average pressure of the fluid at the fluid return outlet.

[0086] The absolute values ​​of the intake pressure can vary depending on the operating conditions. The absolute values ​​of this time-averaged pressure of the fluid at the fluid return outlet can also vary depending on the operating conditions. Furthermore, the ratio between the intake pressure and this time-averaged pressure can vary depending on the operating conditions. However, the time-averaged pressure should, for all (proper) operating conditions, fall within the specified range of 104% to 170%, or, in the further development, 105% to 150% of the intake pressure in the respective operating condition.

[0087] Most preferably, the outlet opening of the fluid port is located outside the outlet area of ​​the compressor channel. This ensures that the outlet opening of the fluid return is never subjected to the outlet pressure from the fluid. In a further development, the outlet opening is arranged in the compressor channel in such a way that it is never in direct fluid communication with a compression chamber of the final stage. Otherwise, an undesirably high intermediate pressure could develop in the outgassing chamber.

[0088] According to another aspect, the fluid return outlet is most preferably arranged at a position angle ε in the compressor channel, wherein ε is in a range from γ - 300° to γ ​​and wherein γ is the position angle of the outer end of the compressor channel.

[0089] The fluid return outlet is preferably arranged at a position angle ε1 in the compressor channel, where ε1 is in a range from γ - 300° to γ ​​- 180°. The outlet can be arranged such that it is only swept by externally guided compression chambers and is closed exactly once per revolution by the orbiting spiral. For example, in this case, the sum of the distance of the outlet from the outside of the compressor channel at this position angle and the width of the outlet in the radial direction can be smaller than the width of the spiral arm of the orbiting spiral in the radial direction at the corresponding position angle of the orbiting spiral.

[0090] Alternatively, the fluid return outlet is most preferably arranged at a position angle ε₂ in the compressor channel, where ε₂ is in a range from γ - 120° to γ. The outlet can be arranged such that it is only swept by internally guided compression chambers and is closed exactly once per revolution by the orbiting spiral. For example, in this case, the sum of the distance of the outlet from the inside of the compressor channel at this position angle and the width of the outlet in the radial direction can be smaller than the width of the spiral arm of the orbiting spiral in the radial direction at the corresponding position angle of the orbiting spiral.

[0091] The fluid return outlet is preferably positioned such that, per revolution, it is in direct fluid contact with the inlet of the compression section (the intake pressure) for a maximum of 130° of the 360° rotation angle of the orbiting disk. Alternatively or additionally, the fluid return outlet is preferably closed by the orbiting spiral for a maximum of 130° of the 360° rotation angle of the orbiting disk per revolution. This ensures that the time-averaged fluid pressure at the fluid return outlet and the intermediate pressure are sufficiently high for efficient oil transfer from the exhaust chamber to the compression section.

[0092] According to another aspect, the spiral compressor is preferably configured so that, during operation, the intermediate pressure is at least 0.1 bar above the time-averaged pressure of the fluid (in the compressor channel) at the outlet of the fluid return. Due to the pressure difference, fluid released in the degassing chamber flows back into the compression section through the fluid return.

[0093] Alternatively or additionally, the scroll compressor is preferably configured so that the intermediate pressure during operation is less than 2 bar above the time-averaged pressure of the fluid (in the compressor channel) at the fluid return outlet. If the intermediate pressure is very high, less of the fluid dissolved in the oil in the exhaust chamber will return to the gas phase. Furthermore, an excessively high intermediate pressure can result in excessive oil flow from the exhaust chamber to the direct oil return outlet. As previously explained, the intermediate pressure and the difference between the intermediate pressure and the time-averaged pressure of the fluid at the fluid return outlet can be easily and precisely controlled by the precise positioning of this outlet.

[0094] For example, the intermediate pressure during operation can be in a range of 0.2 bar to 1.5 bar above the time average pressure of the fluid (in the compressor channel) at the position of the fluid return outlet.

[0095] It is highly preferred that the fluid return inlet in the exhaust chamber be arranged above the oil inlet of the second fluid connection of the direct oil return system. Thus, only separated fluid flows into the fluid return system; correspondingly, liquid oil flows into the second fluid connection of the direct oil return system. "Above" in this context means that, when the scroll compressor is positioned in a desired operating position relative to a direction of gravity, the fluid return inlet opens in front of (i.e., above) the oil inlet of the second fluid connection of the direct oil return system into the exhaust chamber. In particular, the fluid return inlet can be located at an upper end of the exhaust chamber and / or the inlet of the second fluid connection of the direct oil return system can be located at a lower end of the exhaust chamber.

[0096] The desired operating position can be defined, for example, by ensuring that the central axis of the stationary spiral is at least substantially perpendicular to the direction of the gravitational force.

[0097] In a preferred embodiment, the scroll compressor has a discharge pressure chamber, wherein the oil separator is in direct fluid communication with the outlet of the compression section via the discharge pressure chamber. The discharge pressure chamber is in direct fluid communication with the compression section. The oil separator is in direct fluid communication with the discharge pressure chamber and consequently, via the discharge pressure chamber, is in direct fluid communication with the outlet of the compression section. The discharge pressure chamber serves as a damping chamber for the discharged fluid. It smooths the discharge pressure.

[0098] In a particularly preferred embodiment, the exhaust chamber is formed radially outside the exhaust pressure chamber and surrounds it. The exhaust chamber has a substantially hollow cylindrical shape, with the exhaust pressure chamber arranged coaxially in the center of the exhaust chamber. This allows for a very compact design.

[0099] Preferably, the spiral compressor comprises a pressure chamber which is subjected to a pressure during compression operation, wherein the orbiting disk is pressed against the stationary disk by the pressure during operation.

[0100] The pressure chamber is located outside the direct oil return system. The pressure chamber is not part of the direct oil return system. The oil returned via the direct oil return system does not pass through an interior space of the pressure chamber that is subjected to pressure during operation. In a functional sense, the direct oil return system bypasses the interior space of the pressure chamber.

[0101] The direct oil return is spatially separated from the contact pressure chamber. It is separate from the contact pressure chamber.

[0102] In particular, the outgassing chamber may be formed in addition to the contact pressure chamber, i.e., separately. For example, the contact pressure chamber may be arranged parallel to the central axis on a side of the orbiting disk facing away from the orbiting disk. The outgassing chamber, on the other hand, may be arranged parallel to the central axis on a side of the stationary disk facing away from the orbiting disk.

[0103] Particularly preferably, the scroll compressor comprises a second oil return for returning oil from the oil separator to the contact pressure chamber.

[0104] The second oil return supplies oil to the pressure chamber. This second oil return can be used to pressurize the pressure chamber. The rear side of the orbiting disk, facing away from the stationary disk, can form part of the pressure chamber's boundary. Preferably, the second oil return leads directly from the oil separator to the pressure chamber. This ensures low complexity and makes the spiral compressor simple and cost-effective to manufacture.

[0105] In a highly advantageous embodiment of the invention, the second oil return has a flow control valve. The flow control valve influences the operation of the second oil return. In particular, it influences the amount of oil that flows through the second oil return into the pressure chamber. The flow control valve thus assists in adjusting and setting the correct contact pressure in the pressure chamber.

[0106] The flow control valve of the second oil return is preferably designed as a throttle valve. This significantly simplifies the adjustment of the contact pressure via the second oil return (and, if applicable, the reference return connection, see below). This increases the efficiency of the scroll compressor compared to designs without a throttle valve in the second oil return.

[0107] The second oil return is at least partially separate from the direct oil return (first oil return). The second oil return and the direct oil return can share a common initial section. In this case, the direct oil return branches off from the second oil return, with the branch located upstream of the pressure chamber when viewed along the second oil return (in the direction of oil flow). Particularly preferably, the branch is located upstream of the flow valve of the second oil return when viewed along the second oil return (in the direction of oil flow). The common initial section begins with a common oil inlet that opens into the oil separator.

[0108] In a highly preferred embodiment of the invention, the direct oil return has a first oil inlet that opens into the oil separator, and the second oil return has a second oil inlet that opens into the oil separator. The second oil inlet is different from the first oil inlet. The second oil inlet is configured separately from the first oil inlet. In particular, the second oil inlet can be spatially spaced apart from the first oil inlet.

[0109] In a training course, the secondary oil return takes priority over the direct oil return in case of oil shortage. If the amount of liquid oil in the oil separator falls below a predetermined value, the oil flow through the direct oil return is reduced relative to the oil flow through the secondary oil return and / or the oil flow through the direct oil return is stopped completely.

[0110] In this state, less or no oil is introduced into the compression section via direct oil return. Consequently, friction in the compression section increases, and efficiency decreases. However, the pressure chamber continues to be supplied with oil. Temporary lubrication shortages can be compensated for by the oil in the exhaust chamber. This ensures that the orbiting disk continues to be lubricated, at least from its rear side. Furthermore, any parts of the orbiting mechanism located in the pressure chamber are also lubricated. Additionally, the pressure in the pressure chamber can be maintained more easily. Thus, the scroll compressor remains functional, at least to some extent.A certain degree of lubrication of the compression section can be maintained, for example, by oil that creeps from the pressure chamber past the orbiting disk into the compression section, by oil that flows from the pressure chamber into the compression section through a reference connection described below, and / or by oil that is carried along by the aspirated fluid.

[0111] In a particularly preferred embodiment, the first oil inlet is arranged above the second oil inlet. "Above" in this context means that, when the scroll compressor is positioned in the desired operating position relative to the direction of gravity, the first oil inlet opens in front of (i.e., above) the second oil inlet in the oil separator. In other words, the first oil inlet in the oil separator opens above the second oil inlet. In particular, the second oil inlet can be located at the lower end of an oil reservoir within the oil separator. With such an arrangement, if the oil level within the oil separator drops from a normal level, initially only the first oil inlet will run dry.

[0112] Alternatively or additionally, the scroll compressor can have a valve mechanism that automatically reduces or stops the oil flow through the direct oil return when the amount of liquid oil in the oil separator falls below a preset value. The valve mechanism can have one or more valves. If the secondary oil return and the direct oil return share a common initial section, a branch valve can be provided, for example, at the point where the direct oil return branches off from the secondary oil return. The valve mechanism can also include a level sensor that detects when the amount of liquid oil in the oil separator falls below a preset value.

[0113] Alternatively or additionally, the direct oil return is most preferably formed completely separately from the second oil return. This means that the direct oil return does not open directly into the second oil return at any point (and vice versa). In particular, in this case, the two do not have a common initial area. In this sense, the second oil return and the direct oil return are not in direct fluid communication. However, this does not preclude the first oil inlet of the direct oil return and the second oil inlet of the second oil return from being in direct (but indirectly) fluid communication with each other via the interior of the heat exchanger.

[0114] Particularly preferably, the scroll compressor has a reference opening arranged in the compression section and a reference connection that forms a fluid connection between the contact pressure chamber and the reference opening. The reference connection can be designed to influence the contact pressure based on a reference pressure present at the reference opening during operation.

[0115] The reference opening can be formed in the orbiting base area in the compressor channel of the orbiting disk or in the stationary base area in the compressor channel of the stationary disk.

[0116] The reference opening is preferably formed in the compressor channel of the orbiting disk within the orbiting disk's base surface, and the reference connection extends through the orbiting disk. This allows for a very simple and cost-effective implementation of the reference connection.

[0117] The contact pressure is directly influenced by the reference pressure. Given the position of the reference port in the compressor channel, the reference pressure is strongly dependent on the intake pressure and, potentially, also on the outlet pressure. Therefore, any difference between the contact pressure and the intake pressure automatically adjusts to the operating conditions of the scroll compressor. A complex, external, failure-prone, and expensive contact pressure control system is not required. In particular, no actively variable pressure control valve is needed to adjust and regulate the contact pressure. The interaction of the reference return line and the reference port establishes a pressure equilibrium in the contact pressure chamber.Through the targeted design and coordination of the reference return connection and the reference opening, and in particular the precise positioning of the reference opening in the corresponding compressor channel, the automatic adjustment of various desired contact pressures for different operating states of the scroll compressor is achieved. Accordingly, the contact force with which the orbiting disc is pressed against the stationary disc by the contact pressure is adjusted for different operating states to the lifting force acting on the orbiting disc in the respective operating state. This improves the efficiency and reliability of the scroll compressor.

[0118] The reference connection can include a flow control valve. In particular, the flow control valve can be designed as an unregulated throttle valve. This allows for additional control of the contact pressure. The flow control valve can also help prevent pressure differences during one revolution of the orbiting disk from acting undamped on the contact pressure chamber.

[0119] Most preferably, oil from the contact pressure chamber is guided between the stationary disk and the orbiting disk via a reference connection. In this case, in addition to the direct oil return, the scroll compressor has an "indirect oil return" that returns oil from the oil separator indirectly and only indirectly via the interior of the contact pressure chamber to the compression section. The indirect oil return comprises the second oil return and the reference connection. Such an indirect oil return is, of course, not a direct oil return within the meaning of this disclosure.

[0120] In a highly preferred embodiment of the invention, the scroll compressor has two compression chambers, wherein the reference opening is arranged in the compressor channel (the stationary disk or the orbiting disk) such that, during compression operation, the reference opening is in direct fluid contact with a compression chamber of the last stage for a first part of the time required for the revolution and with a compression chamber of the penultimate stage for a further part of the time required for the revolution. The first part and the further part together need not constitute the entire time required for the revolution. Rather, there may be other parts as well.

[0121] This targeted positioning of the reference opening ensures that even a high-pressure area of ​​the scroll compressor influences the contact pressure, and that the contact pressure remains high enough in compression mode in every operating condition, so that the contact force on the orbiting disc is sufficiently greater than the lift-off force. This ensures that the orbiting disc is pressed sealingly against the stationary disc in compression mode in every operating condition.

[0122] The compression chamber of the last stage is characterized by the fact that, during compression operation, the fluid contained therein is at least partially directed into the outlet opening within this revolution of the orbiting disc. The compression chamber of the penultimate stage is characterized by the fact that, during compression operation, the fluid contained therein is at least partially directed into the outlet opening within the next revolution of the orbiting disc.

[0123] For further explanations, details and implementation options regarding the reference return connection and the reference opening, especially for a reference opening in the compressor channel of the stationary disk, reference is made to the publications DE 10 2017 125 968 A1 and WO 2019 / 092024 A1.

[0124] The spiral compressor can have an intake pressure chamber that is in fluid communication with the inlet of the compression section. In particular, the intake pressure chamber can be in direct fluid communication with the inlet of the compression section. The intake pressure chamber must be pressurized during operation.

[0125] The scroll compressor may have a suction port. The suction port may be in fluid communication with the inlet of the compression section via the suction pressure chamber.

[0126] The scroll compressor may have an outlet port. The outlet port may be in fluid communication with the oil separator. Preferably, an oil separator outlet opening for the fluid in the oil separator, which is in direct fluid communication with the outlet port, is arranged above the first oil inlet of the direct oil return (and optionally the second oil inlet of the second oil return). "Above" in this context means that, viewed along the direction of gravity, the oil separator outlet opening is located upstream of (i.e., above) the first oil inlet when the scroll compressor is positioned in the desired operating position relative to the direction of gravity.

[0127] In a further development of the invention, the outlet of the compression section includes a check valve. This can, for example, comprise a check flap and / or a check valve. The check valve prevents compressed fluid from flowing back (against the desired flow direction) through the outlet of the compression section. Otherwise, fluid from the outlet pressure chamber could flow back through the outlet of the compression section if the outlet pressure in the outlet pressure chamber is higher than the pressure at the center of the stationary spiral.

[0128] The check valve can (functionally and / or spatially) form a (downstream) end of the compression section.

[0129] Since the check valve is part of the outlet of the compression section, the oil separator remains in fluid communication with the outlet of the compression section even when the check valve is closed. Similarly, if the outlet pressure chamber is formed between the outlet of the compression section and the oil separator, the outlet pressure chamber, as defined in this application, remains in direct fluid communication with the outlet of the compression section even when the check valve is closed.

[0130] The outlet pressure chamber, the contact pressure chamber, the orbiting disk, the stationary disk, the return connection, and the reference return connection are particularly preferably arranged within the intake pressure chamber. This ensures that all these components are securely enclosed by the intake pressure chamber. In this case, the intake port and the outlet port can be located on the intake pressure chamber, with the outlet port being in pressure-tight fluid communication with the oil separator.

[0131] In a further development of the invention, the stationary spiral has at least 1.25 turns. This corresponds to a spiral angle of at least 450° for the stationary spiral. This ensures sufficient maximum compression of the spiral compressor for typical applications.

[0132] Alternatively and / or additionally, the stationary spiral preferably has a maximum of 2.5 turns. This corresponds to a spiral angle of the stationary spiral of a maximum of 900°. This keeps the spiral compressor compact, lightweight, and inexpensive to produce.

[0133] The stationary spiral particularly preferably has two turns, wherein the reference opening (towards the pressure chamber) in the compressor channel is arranged at a position angle from the inner end of the stationary spiral of at least 315° and at most 435°, most preferably at least 345° and at most 405°. This arrangement has proven to be particularly practical.

[0134] If the second return connection has multiple outlet openings and / or multiple second return connections, each with at least one outlet opening, are provided, the individual outlet openings can be designed independently of one another according to any of the aforementioned embodiments and modifications. The advantages apply accordingly. For example, it is possible that all outlet openings are designed identically, that a first subset of all outlet openings is designed according to a first embodiment and a second subset of all outlet openings is designed according to a second embodiment, or that all outlet openings are designed differently.

[0135] Preferably, the scroll compressor incorporates an electric motor to drive the orbiting disk. Integrating the electric motor into the scroll compressor enables particularly precise and efficient operation. The operation of the electric motor can be precisely tailored to the specific scroll compressor. In particular, the drive of the scroll compressor is then independent of the operating state of other, external components. Most preferably, the electric motor is arranged within the intake chamber. In a particularly preferred embodiment, the scroll compressor is an electric scroll compressor with an integrated inverter.

[0136] Alternatively and / or additionally, the spiral compressor can also have a power transmission device for driving the orbiting disc by an external drive unit. This external drive unit could, for example, be an internal combustion engine. The power transmission device can include a clutch (such as a magnetic clutch).

[0137] Optionally, the spiral compressor can also be used in a heat pump system, for example. This is of particular interest for the air conditioning of electric vehicles and / or full hybrid vehicles.

[0138] The invention further relates to an air conditioning system with a scroll compressor according to the invention. In particular, it can be an air conditioning system for a motor vehicle.

[0139] The described design options and advantages for the scroll compressor apply accordingly to the system.

[0140] The invention is explained below using exemplary embodiments and with reference to the figures. All described and / or illustrated features, individually or in any combination, constitute the subject matter of the invention, regardless of their summary in the claims or their references.

[0141] They show schematically: Fig. 1 shows a longitudinal section of a first embodiment of a spiral compressor according to the invention; Fig. 2 shows a compression section, an oil separator and a direct oil return for the direct return of oil from the oil separator to the compression section of the spiral compressor. Fig. 1 ; Fig. 3 a cross-section of the compression section made of Fig. 1 with two outlet openings for direct oil return and one outlet opening for fluid return for returning refrigerant from an exhaust chamber of the direct oil return, wherein all these outlet openings are arranged in a stationary disk of a stationary spiral of the compression section and wherein only one orbiting spiral of an orbiting disk of the compression section is visible; Fig. 4 a top view of a modification of the stationary disk of the spiral compressor made of Fig. 3 for a precise explanation of a preferred arrangement of the outlet openings of the direct oil return; Fig. 5 a longitudinal section of a compression section, an outlet pressure chamber, an oil separator and a direct oil return for the direct return of oil from the oil separator to the compression section according to a second embodiment of a spiral compressor according to the invention; Fig. 6 a cross-section at section line A in Fig. 5 ; and Fig. 7 the top view of the stationary disk from Fig. 3 Fig. 7 To explain advantageous positions for fluid return outlet openings.

[0142] In Fig. 1 Figure 1 schematically shows a first embodiment of a spiral compressor 1 according to the invention for compressing a fluid in a longitudinal section. The fluid is, for example, a refrigerant or a refrigerant mixture from a refrigerant circuit.

[0143] The spiral compressor 1 comprises a compression section 10 with an inlet 11, a stationary disk 20, an orbiting disk 30, and an outlet 12. An outlet pressure chamber 40 is directly connected to the outlet 12. In this embodiment, the outlet 12 includes a check valve 13, which prevents compressed refrigerant from flowing back from the outlet pressure chamber 40 into the compression section 10. The check valve 13 is shown here by way of example as a check valve and forms a downstream end of the compression section 10.

[0144] Viewed along the direction of refrigerant flow (during operation), an oil separator 45 is directly connected to the outlet pressure chamber 40. The oil separator 45 is therefore in direct fluid communication with the outlet pressure chamber 40 and – via the outlet pressure chamber 40 – in direct fluid communication with the outlet 12 of the compression section 10.

[0145] The scroll compressor 1 comprises a housing 90 with an intake port 91 and an outlet port 92.

[0146] The intake port 91 is in direct fluid communication with the inlet 11 of the compression section 10 via an intake pressure chamber 93. During operation, refrigerant is drawn in from an external refrigerant circuit via the intake port 91.

[0147] The outlet 92 is in direct fluid communication with an oil separator outlet opening 46 of the oil separator 45. During operation, compressed refrigerant is discharged into the external refrigerant circuit via the outlet 92.

[0148] During operation, an intake pressure is present in the intake pressure chamber 93 and the inlet 11 of the compression section. This intake pressure can range, for example, from 0.7 bar to 9 bar. During operation, an outlet pressure, higher than the intake pressure, prevails in the outlet pressure chamber 40, the oil separator 45, and the outlet port 92. This outlet pressure can range, for example, from 6 bar to 32 bar. The intake and outlet pressures depend, among other things, on the refrigerant used and the operating condition of the external refrigerant circuit.

[0149] The intake pressure chamber 93 is in Fig. 1 Shown only schematically. Preferably, the intake pressure chamber 93 encloses at least the pressure chamber 80 in a mantle-like manner. That is, the intake pressure chamber 93 extends completely around the pressure chamber 80 along a circumferential direction (relative to the central axis). Alternatively or additionally, the intake pressure chamber 93 can enclose at least a portion of the compression section 10 in a mantle-like manner. That is, the intake pressure chamber 93 extends completely around the aforementioned portion of the compression section 10 along its circumferential direction (relative to the central axis). This portion of the compression section 10 can, in particular, face the pressure chamber 80 when viewed along its central axis.

[0150] The intake pressure chamber 93 can, for example, be designed at least substantially in a cylindrical shape around the pressure chamber 80 and / or at least a part of the compression section 10 on the side of the pressure chamber 80.

[0151] The stationary disk 20 faces the outlet pressure chamber 40, while the orbiting disk 30 faces a contact pressure chamber 80.

[0152] An intersection for Fig. 3 lies between the orbiting disk 30 and the stationary disk 20 in Fig. 1 or Fig. 2 and extends parallel to a stationary base surface 22 of the stationary disk 20. A stationary spiral 21 with 2.25 turns is arranged on the stationary base surface 22. Accordingly, an outer end 25 of the stationary spiral 21 is arranged at a spiral angle of 810° from an inner end 24 of the stationary spiral 21.

[0153] Fig. 4 This is a simplified representation of a top view of the stationary disk 20. For simplification, the orbiting spiral 31 is shown in Fig. 4 in a modification with two turns. Accordingly, the outer end 25 of the stationary spiral 21 is arranged at a spiral angle of 720° from the inner end 24 of the stationary spiral 21. Otherwise, the structure and function of the stationary disk 20 are shown in Fig. 3 und Fig. 4 the same and the same reference numerals are used for the same elements.

[0154] Back to Fig. 3 Due to the cross section of the orbiting disk 30, only an orbiting spiral 31 can be seen, which is mounted on an orbiting base surface 32 (in Fig. 3 not shown, but see Fig. 5 ) of the orbiting disk 30. The orbiting spiral 31 has (as the design of the stationary spiral 21 in Fig. 3 ) 2.25 turns.

[0155] The stationary disk 20 and the orbiting disk 30 are nested within each other. During (compression) operation, the orbiting disk 30 is held in place by a contact pressure in the contact pressure chamber 80 (see Fig. 1 ) pressed onto the stationary disk 20. As a result, on the one hand, an end face of the orbiting spiral 31 facing away from the orbiting base surface 32 is in close contact with the stationary base surface 22, and on the other hand, an end face of the stationary spiral 21 facing away from the stationary base surface 22 is in close contact with the orbiting base surface 32.

[0156] The stationary base area 22, the stationary spiral 21, the orbiting base area 32 and the orbiting spiral 31 thereby define several compression spaces 14a, 14b, 14c.

[0157] In the Fig. 3 In the positions of the orbiting disk 30 and the orbiting spiral 31 shown, a compression chamber 14c of the last stage and two compression chambers 14a, 14b of the penultimate stage are bounded in a compressor channel 26, which is formed between the turns of the stationary spiral 21, wherein the compression chamber 14c of the last stage comprises two sub-areas which are separated by narrow gaps (in Fig. 3 (not visible) between the stationary spiral 21 and the orbiting spiral 31 are in fluid communication with each other.

[0158] On the left side of the Fig. 3 A vector diagram is shown that represents an orbital angle 103 of the orbiting disk 30 (and thus of the orbiting spiral 31) and its orbital direction or a compression direction 100. The orbiting disk 30 begins a new orbit when its orbital position 103 in the vector diagram is at an orbital angle 101 of 0°. Then, an outer side of the orbiting spiral 31 just touches the outer end 25 of the stationary spiral 21, thereby closing off the externally guided compression chamber of the penultimate stage 14b. At the same time, an outer end 34 of the orbiting spiral 31 touches an outer side of an outermost turn of the stationary spiral 21, thereby closing off the internally guided compression chamber of the penultimate stage 14a. Fig. 3 The orbiting disk 30 has already moved from the rotation angle 101 of 0° along the compression direction 100 to the rotation position 103 of 45°. Starting from Fig. 3 The orbiting disk 30 continues to orbit along the compression direction 100 around a center of the stationary spiral 21.

[0159] If the orbiting disk 30 starts from Fig. 3 orbits a further 270° along the compression direction 100 relative to the stationary disk 20, it reaches an orbital position of 0° and its current orbit ends. The refrigerant that is in Fig. 3 A large portion of the compressed air that had been located in the compression chamber of the last stage 14c was directed into an outlet opening 28 in the stationary base area 22 and thus to the outlet 12 of the compression section 10. The outlet opening 28 is arranged in a center of the stationary disk 20 or the stationary spiral 21.

[0160] The spiral compressor 1 has a direct oil return 50 for returning oil from oil separator 45 to the compression section 10.

[0161] More specifically, the direct oil return 50 extends from a first oil inlet 51 in the oil separator 54 to two orifices 59a, 59b in the stationary base 22 of the stationary disk 20. During operation, the direct oil return 50 injects oil from the oil separator 45 from the orifices 59a, 59b directly between the stationary disk 20 and the orbiting disk 30.

[0162] In the Fig. 1 In the illustrated embodiment, the direct oil return 50, viewed along the direction of oil flow, comprises the first oil inlet 51, a first fluid connection 52 with a first throttle valve 53, an exhaust chamber 54, a second fluid connection 56 with a second throttle valve 57 and a branch 58, and furthermore two outlet openings 59a, 59b.

[0163] During operation, the outlet pressure prevails inside the oil separator 45. The refrigerant rises in the oil separator 45, while liquid oil collects in a lower half of the oil separator 45. This separates the refrigerant and the oil. Due to the high outlet pressure, the refrigerant has increased solubility in the liquid oil, and the liquid oil contains a portion of dissolved refrigerant.

[0164] The first oil inlet 51 is located in a lower half of an interior space of the oil separator 45, while the oil separator outlet opening is located at an upper end of the interior space of the oil separator 45. The outlet pressure forces liquid oil from the oil separator 45 through the first oil inlet 51 into the first fluid connection 52.

[0165] In the first fluid connection 52 of the direct oil return 50, this oil flows through the first throttle valve 53. The first throttle valve 53 can be designed as an unregulated throttle valve. For example, the first throttle valve 53 can be designed as an orifice or nozzle. The first throttle valve 53 reduces the mass flow rate of the oil. The oil then flows on into the degassing chamber 54. By influencing the mass flow rate of the oil, an intermediate pressure in the degassing chamber 54 can be controlled. Due to the pressure drop, the solubility of the refrigerant in the oil decreases. The oil can be supersaturated with refrigerant after the first throttle valve 53. In the degassing chamber 54, a portion of the supersaturated refrigerant can evaporate. Liquid oil collects in a lower region of the degassing chamber 54, and refrigerant collects in an upper region.The outgassing chamber 54 acts, so to speak, as an additional oil separator for the direct oil return 50 and a fluid return 70.

[0166] In the lower region of the exhaust chamber 54, for example at the bottom of the exhaust chamber 54, an oil inlet 55 of the second fluid connection 56 of the direct oil return 50 is arranged. Due to the intermediate pressure prevailing in the exhaust chamber 54, liquid oil is forced from the exhaust chamber 54 through the oil inlet 55 into the second fluid connection 56.

[0167] The second fluid connection 56 has a second throttle valve 57, which limits the mass flow of the oil exiting the exhaust chamber. This also prevents an undesirably sharp drop in the intermediate pressure in the exhaust chamber 54. The second throttle valve 57 can also be designed as an unregulated throttle valve, for example as an orifice or nozzle.

[0168] Downstream of the second throttle valve 57, the second fluid connection 56 branches into two arms at a junction 58. Both arms extend at least partially through the stationary disk 20. They each terminate in one of the outlet openings 59a, 59b, which are arranged in the stationary base surface 22.

[0169] Each of the orifices 59a, 59b is arranged in an inlet region of the compression section 10, which, during operation, is at least temporarily in direct fluid communication with the inlet 11 of the compression section 10. As a result, oil escaping from the orifices 59a, 59b is entrained by the drawn-in refrigerant and then enclosed together with the refrigerant in newly formed compression chambers. Because the orifices 59a, 59b are each positioned in the inlet region of the compression section 10, the radially outer engagement regions of the stationary scroll 21 and the orbiting scroll 31 are also excellently lubricated.

[0170] Furthermore, all outlet openings 59a, 59b are brushed at least once by the orbiting spiral 31 during each revolution of the orbiting disk 30. This ensures good distribution of the supplied oil. The oil exiting the outlet openings 59a, 59b is smeared by the orbiting spiral 31. Fig. 4 It is evident, for example, that the muzzle opening 59a is swept over by an outer end 34 of the orbiting spiral 31 in each revolution.

[0171] Particularly preferred positionings of the muzzle openings 59a, 59b are described below with reference to Fig. 4 discussed in more detail.

[0172] In compression chambers 14a, 14b, 14c (see Fig. 3 ), which are formed in the compression section 10 between the stationary disk 20 and the orbiting disk 30, the refrigerant is transported to the center of the stationary scroll 21 and compressed by reducing the volumes of the compression chambers 14a, 14b, 14c until it reaches the outlet pressure. It is then conveyed through the outlet 12, which in this example comprises an outlet opening 28 in the center of the stationary disk 20 and the check device 13, and the outlet pressure chamber 40 into the oil separator 45.

[0173] Oil is also transported along with the refrigerant and ultimately returns to the oil separator 45. There, it is separated from the refrigerant and is available for a new cycle of direct oil return 50. The refrigerant, freed of oil, compressed, and at the outlet pressure, is discharged from the scroll compressor 1 through the oil separator outlet opening 46 and the outlet connection 92.

[0174] Based on Fig. 4 It will now be explained where the outlet openings 59a, 59b of the direct oil return can preferably be arranged.

[0175] A position angle of 0° is defined by the inner end 24 of the stationary spiral 21. It should be noted that a termination bead 24a of the inner end 24 is irrelevant for defining the position angle of 0°. Since the stationary spiral 21 in Fig. 4 Having two turns, its outer end 25 is arranged at a position angle or spiral angle of 720°. Accordingly, an inlet opening of a compressor channel 26, which extends between the outer end 25 and the beginning of an outer turn of the stationary spiral 21 at a position angle of 360°, is located at the position angle 720°.

[0176] Fig. 4 shows a preferred first area AM,1 for the arrangement of the outlet openings for direct oil return 50.

[0177] In Fig. 4 γ is a position angle of the outer end 25 of the stationary spiral 21. Correspondingly, γ is also a position angle of an outer end of the compressor channel 26. At the position angle γ, the inner side of the stationary spiral 21 has a radial distance RI(γ) from the center of the stationary spiral 21. Simultaneously, an inlet opening of the compressor channel 26 of the stationary disk 20 has a radial width BK at the position angle. The width BK is given here as BK = RI(γ) - RA(γ - 360°), where RA(γ - 360°) is the distance of the outer side of the stationary spiral 21 at a position angle corresponding to γ ​​- 360°.

[0178] The first region AM,1 extends circumferentially from a position angle γ - 30° to a position angle of γ + 30° and radially from RI (γ) - BK / 2 to RI (γ). This means that the first region AM,1 is arranged at the inlet opening of the compressor channel 26, specifically on a radially outer half of the compressor channel 26 in this position angle range or its imaginary continuation.

[0179] In Fig. 4 The outlet opening 59a is positioned in the first area AM,1, precisely at the position angle γ = 720° and close to the outside of the compressor channel 26, i.e., for example, at a radial distance RI (γ) - BK / 10 from the center of the stationary scroll 21. The outlet opening 59a is closed only once per revolution by the orbiting scroll 31. In the embodiment shown, it does not directly communicate with the internally guided compression chambers 14b. The outlet opening 59a ensures the lubrication of the external compression chambers in a particularly advantageous manner. Fig. 3 the compression chamber 14a is guided on the outside.

[0180] Fig. 4 Figure 1 further shows a preferred second region AM,2 for the arrangement of the outlet openings of the direct oil return 50. In this example, the outlet opening 59b is positioned in the second region AM,2.

[0181] The second region AM,2 extends radially outside the stationary spiral 21 around a position angle θ, where θ = γ + 180°. This second region AM,2 extends circumferentially from a position angle θ - 30° to a position angle of θ + 30° and radially from RA (θ) - 360° to RA (θ - 360°) + BK / 2. Therefore, a second region AM,2 lies outside the compressor channel 26 of the stationary disk 20, more precisely on the side opposite the inlet opening of the compressor channel 26. Here, RA (θ - 360°) is a radial distance from the outer surface of the stationary spiral 21 at the position angle θ - 360° = γ - 180°.

[0182] In Fig. 4 The orifice 59b is positioned in the second area AM,2, precisely at the position angle θ = 900° and close to the outside of the outermost turn of the stationary spiral 21, for example, at a radial distance RA (θ) + BK / 10 from the center of the stationary spiral 21. The orifice 59b ensures the lubrication of internally guided compression chambers in a particularly advantageous manner. Fig. 3 The compression chamber 14b is guided on the inside.

[0183] In Fig. 3 Are the outlet openings 59a, 59b of the direct oil return 50 also positioned as described with reference to Fig. 4 has been described.

[0184] The spiral compressor 1 further comprises a fluid return 70 for returning refrigerant from the exhaust chamber 54 to the compression unit. A fluid inlet 71 of the fluid return 70 is located in an upper region of the exhaust chamber 54. This prevents liquid oil from flowing from the exhaust chamber 54 into the fluid return 70.

[0185] The fluid return 70 extends through the stationary disk 20. An outlet opening 72a of the fluid return 70 is arranged in the compressor channel 26 of the stationary disk 20 (see Fig. 3 and Fig. 5 Here, the outlet opening 72a is located in an inlet area of ​​the compressor channel 26, but is also temporarily swept over by closed compression chambers. Fig. 3 The compression chamber 14b of the penultimate stage directly overlies the outlet opening 72a. Consequently, the time-averaged pressure of the refrigerant in the compressor channel 26 at the outlet opening 72a is higher than the intake pressure. In the present embodiment, the intermediate pressure in the exhaust chamber 54, under normal operating conditions, is higher than the time-averaged pressure of the refrigerant in the compressor channel 26 at the position of the outlet opening 72a, specifically—depending on the exact operating conditions—in the range of 0.2 bar to 1.5 bar. The pressure difference to the outlet pressure forces liquid oil out of the exhaust chamber into the second fluid connection 56 and out of the outlet openings 59a and 59b of the direct oil return 50.

[0186] The intermediate pressure in the outgassing chamber 54 is particularly influenced by: The outlet pressure and the mass flow rate of the oil together with the transported refrigerant, which flow through the first fluid connection 52 into the exhaust chamber 54, the time averages of the pressures at the outlet openings 59a and 59b and the corresponding mass flow rate of the oil leaving the exhaust chamber 54 through the second fluid connection 56, and the time average of the pressure of the refrigerant in the compressor channel 26 at the outlet opening 72a and the corresponding mass flow rate of the refrigerant leaving the exhaust chamber 54 through the fluid return 70.

[0187] The driving force is the outlet pressure in the oil separator 45.

[0188] In this embodiment, the intermediate pressure (or a time-averaged intermediate pressure under unchanged operating conditions) ranges from 0.3 bar to 5 bar above the intake pressure during operation. At an intake pressure of 1 bar, the intermediate pressure during operation is a minimum of 0.3 bar above the intake pressure, i.e., 1.3 bar, and a maximum of 1.9 bar, i.e., 1.9 bar. At an intake pressure of 7 bar, the intermediate pressure during operation is a maximum of 4.2 bar above the intake pressure, i.e., 11.2 bar. Naturally, the intermediate pressure remains significantly below the outlet pressure, which in this case is 32 bar. At an intake pressure of 5 bar, the intermediate pressure ranges from 0.6 bar to 3.5 bar above the intake pressure. These values ​​are examples. The exact intermediate pressure depends on the specific operating conditions, including, for example, the outlet pressure. The precise pressure ratios can also depend on the refrigerant used.

[0189] In other words, the intermediate pressure during operation ranges from 1.3 bar (minimum intermediate pressure) to 11.2 bar (maximum intermediate pressure).

[0190] Based on Fig. 7 Advantageous positions for the outlet openings 72a, 72b of the fluid return 70 are explained below.

[0191] In general, the outlet opening 72a, 72b of the fluid return 70 in the compressor channel 26 is preferably arranged at a position angle (of the compressor channel 26) that lies in a range of ε min = γ - 300° and ε max = γ, where γ is the position angle of the outer end of the compressor channel.

[0192] Fig. 7 Figure 1 shows two particularly preferred areas AM,3 and AM,4 for the arrangement of outlet openings 72a, 72b of the fluid return 70 in the compressor channel 26.

[0193] One area AM,3 for the arrangement of outlet openings 72a is defined by the fact that an outlet opening 72a of the fluid return 70 located therein is arranged at a position angle ε 1, which is in a range from ε min = γ - 300° to ε max,1 = γ - 180°, wherein the outlet opening 72a is also arranged such that it is only swept by externally guided compression chambers 14b and is swept exactly once per revolution by the orbiting spiral 31. For example, the outlet opening 72a of the fluid return 70 is in Fig. 3, Fig. 4 and Fig. 7 The compressor channel 26 is arranged at a position angle ε₁ = γ - 248°. The outlet opening 72a is also arranged on the outside of the compressor channel 26 at this position angle. Therefore, in this embodiment, the outlet opening 72a is only swept by externally guided compression chambers 14b. The outlet opening 72a is never in direct fluid contact with any of the internally guided compression chambers 14a.

[0194] More precisely, in this embodiment, the orbital opening 72a of the fluid return 70 is closed by the orbiting spiral 31 in the range of the rotation angle from 0° to 20°. When the rotation angle reaches 20°, the externally guided compression chamber 14b begins to sweep over the orbital opening 72a. In a range of the rotation angle from 20° to 270°, the orbital opening 72a and the externally guided compression chamber 14b are in fluid communication. In the Fig. 3 For example, at the orbital angle of 90° shown, the orifice 72a of the fluid return 70 is in direct fluid communication with the externally guided compression chamber 14b over its entire surface. In a range of the orbital angle from 270° to 360°, the orbiting spiral 31 closes the orifice 72a again.

[0195] At a rotation angle of 20°, the refrigerant pressure in the externally routed compression chamber 14b, which is just entering fluid contact with the outlet opening 72a, is already slightly above the intake pressure. This is because this compression chamber 14b was previously closed off at a rotation angle of 0° (reference numeral 101) and had already been reduced in size somewhat by the time the rotation angle of 20° was reached.

[0196] For the following example, let's assume an intake pressure of 3 bar. Then, at a rotation angle of 20°, the refrigerant pressure in this compression chamber 14b is, for example, 3.08 bar. Up to a rotation angle of 270°, the refrigerant pressure in this compression chamber 14b increases continuously to 4.76 bar in this example. The time-averaged refrigerant pressure in the compressor channel 26 at the outlet 72a is 3.76 bar, which is 0.76 bar above the intake pressure of 3 bar. This is a non-limiting example for a specific operating condition.

[0197] Thus, in the embodiment according to Fig. 3 the time average of the pressure of the refrigerant in the compressor channel 26 at the position of the orifice 72a of the fluid return 70, for example at an intake pressure of 1 bar at 126% of this intake pressure, at an intake pressure of 3 bar at 125% of this intake pressure, at an intake pressure of 5 bar at 124% of this intake pressure and at an intake pressure of 7 bar at 123% of this intake pressure.

[0198] If the outlet opening 72a of the fluid return 70 is shifted to a position angle of ε 1 = γ - 295° in a modification of the embodiment not shown in the area AM,3, then the time average value of the pressure of the refrigerant in the compressor channel 26 at the position of the outlet opening 72a of the fluid return 70 is, depending on the operating condition, for example in the range of 138 % to 142 % of the respective intake pressure.

[0199] If the outlet opening 72a of the fluid return 70 is shifted to a position angle of ε 1 = γ - 190° in a modification of the embodiment not shown in the area AM,3, then the time average value of the pressure of the refrigerant in the compressor channel 26 at the position of the outlet opening 72a of the fluid return 70 is, depending on the operating condition, for example in the range of 107 % to 109 % of the respective intake pressure.

[0200] The other area AM,4 for the arrangement of outlet openings 72b' is defined by the fact that an outlet opening 72b of the fluid return 70 located therein is arranged at a position angle ε 2 which is in a range from ε min,2 = γ - 120° to ε max = γ, wherein the outlet opening 72b is also arranged such that it is only swept over by internally guided compression chambers 14a and is swept over exactly once per revolution by the orbiting spiral 31.

[0201] In Fig. 7 The position for an outlet opening 72b in area AM,4 with a position angle ε 2 = γ - 68° is shown as an example. The outlet opening 72b is also located on the inside of the compressor channel 26 at this position angle ε 2. As a result, this outlet opening 72b is only swept by internally guided compression chambers 14a. Therefore, the outlet opening 72b is never in direct fluid contact with any of the externally guided compression chambers 14b. This outlet opening 72b can be used as an alternative or in addition to the other one in Fig. 7 The fluid return 70 is formed at the shown outlet opening 72a.

[0202] Upon closure of the compression chambers 14a, 14b, the position angle of the internally guided compression chambers 14b is offset by +180° relative to the position angle of the externally guided compression chambers 14a. Since the position angle of the outlet opening 72b is also offset by +180° relative to that of the outlet opening 72a, the pressure conditions at the outlet opening 72b develop similarly to those at the outlet opening 72a during one revolution.

[0203] In an embodiment not shown, a fluid return outlet 70 can, for example, be arranged at a position angle in the range of εmax,1 to εmin,2. Such an outlet can be located in a central region of the compressor channel 26 at this position angle, such that it is completely closed twice in each revolution by the orbiting spiral 31 and alternately comes into fluid contact with internally guided compression chambers 14a and with externally guided compression chambers 14b. As a result, the mean refrigerant pressure at this outlet lies between the mean refrigerant pressure in externally guided compression chambers 14b on the outside of the compressor channel 26 at this position angle and the mean refrigerant pressure in internally guided compression chambers 14a on the inside of the compressor channel 26 at this position angle.As already mentioned elsewhere, the time periods during which the outlet opening is completely closed by the orbiting spiral 31 can be left out of the calculation of the average pressure of the refrigerant at the outlet opening.

[0204] The scroll compressor 1 also has a second oil return 82. The second oil return 82 returns oil from the oil separator 45 to the contact pressure chamber 80. It comprises a second oil inlet 81 in the oil separator 45 and a throttle valve 83 arranged between the second oil inlet and the contact pressure chamber 80 in the second oil return 82.

[0205] During operation, the outlet pressure prevailing in the oil separator 45 forces oil through the second oil inlet 81 into the second oil return 82. The oil pressure is reduced by the throttle valve 83. The pressure drop in the throttle valve 83 influences the contact pressure.

[0206] The oil in the pressure chamber 80 contributes to the lubrication of the orbiting disk 30. In addition, a small portion of the oil can creep past the orbiting disk 30 into the interior of the compression section 10.

[0207] The Fig. 1 The scroll compressor 1 shown also comprises a reference connection 84 between an interior of the contact pressure chamber 80 and a reference opening 86. The reference opening 86 is arranged in the orbiting base surface 32 of the orbiting disk 30, specifically in a compressor channel of the orbiting disk 30. The reference connection 84 influences the contact pressure in the contact pressure chamber 80 depending on the operating state of the scroll compressor 1. The reference connection 84 leads from the contact pressure chamber 80 through the orbiting disk 30 to the reference opening 86 in the orbiting base surface 32.

[0208] The reference opening 86 of the reference connection 84 is positioned further inwards in the radial direction than the outlet openings 59a, 59b of the direct oil return 50. Fig. 3 The position of the reference opening 86 of the reference connection 84 is indicated in an outlet region of the compressor channel of the orbiting disk 30. Therefore, the reference connection 84 can contribute little or not at all to the lubrication of the radially outer regions of the stationary spiral 21 and the orbiting spiral 31. The reference opening 86 is not located in the inlet region of the compressor channel of the orbiting disk 30. Consequently, during operation of the scroll compressor 1, there is no direct fluid connection between the inlet 11 of the compression section 10 and the reference opening 86.

[0209] Optionally, the reference connection 84 includes a throttle valve 85. The throttle valve 85 helps to regulate the contact pressure.

[0210] The second oil inlet 81 of the second oil return 82 is located in a base area of ​​the oil separator 45. Specifically, it is situated below the first oil inlet 51 of the direct oil return 50. If, during operation, the oil level in the oil separator 45 drops below the level of the first oil inlet 51, the first oil inlet 51 runs dry and is no longer supplied with oil. However, the second oil inlet 81 continues to be supplied with oil. The oil supply to the second oil return thus takes priority over the oil supply to the direct oil return 50. This ensures that the contact pressure is maintained even in the event of an oil shortage. A certain degree of lubrication of the compression section 10 is maintained by the oil creeping past the outside of the orbiting disk 30, as well as by oil that returns to the inlet 11 of the compression section 10 from the external refrigerant circuit.Furthermore, oil from the pressure chamber 80 can enter the compression section 10 through the reference connection 84, especially if the oil level in the pressure chamber is very high.

[0211] The scroll compressor 1 also includes an electric motor and an inverter for the electric motor (not shown). The scroll compressor 1 can be integrated into a vehicle's refrigerant circuit. For example, the scroll compressor 1 can be installed in an electric vehicle or a hybrid vehicle.

[0212] Fig. 5 shows a longitudinal section of a compression section 10, a discharge pressure chamber 40, an oil separator 45, and a direct oil return 50 for the direct return of oil from the oil separator 45 to the compression section 10 according to a second embodiment of a scroll compressor according to the invention. The remaining elements of this scroll compressor are not shown. The scroll compressor and its components correspond to the structure and operation of the scroll compressor 1 from Fig. 1 Unless otherwise specified, the same reference symbols are used for identical elements.

[0213] Fig. 6 shows a cross section along section line A in Fig. 5 .

[0214] In Fig. 5 und Fig. 6 It is shown that the exhaust chamber 54 is formed radially (perpendicular to the central axis of the stationary disk 20) ​​outside the exhaust pressure chamber 40 and surrounds the exhaust pressure chamber 40. The exhaust chamber 54 has a (at least substantially) hollow cylindrical basic shape. The exhaust pressure chamber 40 has a (at least substantially) cylindrical basic shape. The exhaust pressure chamber 40 and the exhaust chamber 54 are arranged coaxially. A hollow cylindrical outer wall 41 of the exhaust pressure chamber 40 separates the exhaust pressure chamber 40 and the exhaust chamber 45 from each other. In this way, the otherwise unused space around the outer wall 41 is advantageously utilized.

[0215] The outlet pressure chamber 40 is in direct fluid communication with the oil separator 45 via an opening 42. Similar to in Fig. 1 Optionally, a non-return device can be provided at the outlet 11 of the compression unit 10 (not shown).

[0216] The described embodiments with the direct oil return 50 allow particularly efficient operation and have a high level of reliability. Bezugszeichenliste:

[0217] 1 Spiral compressor 10 Compression section 11 Inlet (of the compression section) 12 Outlet (of the compression section) 13 Check valve 14a, 14b, 14c Compression chamber 20 Stationary disc 21 Stationary spiral 22 Stationary base 24 Inner end (of the stationary spiral) 25 Outer end (of the stationary spiral) 26 Compressor channel (of the stationary disc) 28 Outlet opening (of the stationary disc) 30 Orbiting disc 31 Orbiting spiral 32 Orbiting base 34 Outer end (of the orbiting spiral) 40 Outlet pressure chamber 41 Casing wall 42 Opening 45 Oil separator 46 Oil separator outlet opening 50 Direct oil return 51 First oil inlet 52 First fluid connection 53 First flow valve (throttle valve) 54 Exhaust chamber 55 Oil inlet 56 Second fluid connection 57 Second flow valve (throttle valve) 58 Branch 59a, 59b Outlet (of direct oil return) 70 Fluid return 71 Fluid inlet 72a,72b Outlet opening (of fluid return) 80 Pressure chamber 81 Second oil inlet 83 Flow valve (throttle valve) 84 Reference connection 85 Flow valve (throttle valve) 86 Reference opening 90 Housing 91 Intake port 92 Outlet port 93 Intake pressure chamber AM,1 , AM,2 , AM,3 , AM,4 Range ε ​​1 , ε 2 , ε min , ε max Position angle ε 1,max , ε 2,min Position angle γ Position angle of the outer end of the compressor channel θ Position angle RI (γ) Radial distance of the inside of the stationary spiral at the outer end of the compressor channel BK Width of the compressor channel in the radial direction at the outer end of the compressor channel RA (θ - 360°) Radial distance of the outside the stationary spiral at the position angle θ - 360°,

Claims

1. Scroll compressor (1) for compressing a fluid, comprising: a compression section (10) with • an inlet (11) of the compression section (10) for sucking the fluid into the compression section (10), • an outlet (12) of the compression section (10) for discharging the compressed fluid out of the compression section (10), • a stationary disk (20) having a stationary spiral (21), and • an orbiting disk (30) having an orbiting spiral (31), the orbiting disk (30) being orbitable relative to the stationary disk (20) along a compression direction (100) to move the fluid from the inlet (11) of the compression section (10) to the outlet (12) of the compression section (10), thereby compressing the fluid; and an oil separator (45) for separating oil from the compressed fluid; wherein the scroll compressor (1) additionally comprises a direct oil return (50) for directly returning oil from the oil separator (45) to the compression section (10), the direct oil return (50) comprising at least one orifice opening (59a, 59b), wherein the direct oil return (50) comprises a first flow valve (53), characterized in that the direct oil return (50) comprises an outgassing chamber (54) arranged between the first flow valve (53) and the orifice opening (59a, 59b) of the direct oil return (50), and in that the scroll compressor (1) has a fluid return (70) for returning fluid from the outgassing chamber (54) to the compression section (10).

2. Scroll compressor (1) according to claim 1, characterized in that the orifice opening (59a, 59b) of the direct oil return (50) is arranged in the stationary disk (20).

3. Scroll compressor (1) according to claim 2, wherein the stationary disk (20) comprises a stationary spiral (21) arranged on a stationary base (22) of the stationary disk (20) and forming a spiral compressor channel (26) of the stationary disk (20), characterized in that the orifice opening (59a, 59b) of the direct oil return (50) is arranged in an intake portion of the compressor channel (26) which, in operation, is at least temporarily in direct fluid communication with the inlet (11) of the compression section (10) and / or is arranged outside the compressor channel (26).

4. Scroll compressor (1) according to one of the preceding claims, wherein the stationary disk (20) comprises the stationary spiral (21), which is arranged on the stationary base (22) of the stationary disk (20) and forms the spiral-shaped compressor channel (26), characterized in that the orifice opening (59a, 59b) of the direct oil return (50) either is disposed at a position angle in a range of γ - 30° and γ + 30°, where γ is a position angle of an outer end of the compressor channel (26), and is disposed at a radial distance RM,1 from a center of the stationary disk (20), where RM,1 is in a range between (RI(γ) - BK) and RI(γ), where RI(γ) is a radial distance of an inner side of the stationary spiral (21) at an outer end of the compressor channel (26), and BK is a width of the compressor channel (26) along the radial direction at the outer end of the compressor channel (26), or outside the stationary spiral (21) and at a position angle in the range of θ - 30° to θ + 30°, and at a radial distance RM,2 from the center of the stationary disk (20), where θ = γ + 180°, and RM,2 is in a range of RA(θ - 360°) to RA(θ - 360°) + BK, where RA(θ - 360°) is a radial distance of an outer side of the stationary spiral (21) at the position angle θ - 360°.

5. Scroll compressor (1) according to any one of the preceding claims, wherein during compression operation at least one compression chamber (14a, 14b, 14c) is formed between the orbiting spiral (31) and the stationary spiral (21), characterized in that the at least one orifice opening (59a, 59b) is not swept by any compression chamber°(14a, 14b, 14c) at any time.

6. Scroll compressor (1) according to any of the preceding claims, characterized in that the direct oil return (50) comprises a second flow valve (57) arranged after of the outgassing chamber (54).

7. Scroll compressor (1) according to one of the preceding claims, characterized in that the scroll compressor (1) is configured such that, during compression operation, the intermediate pressure in the outgassing chamber (54) is in a range from 0.2 bar to 6 bar above an intake pressure of the compression section (10).

8. Scroll compressor (1) according to one of the preceding claims, characterized in that the scroll compressor (1) has an outlet pressure chamber (40), the oil separator (45) being in direct fluid communication with the outlet (12) of the compression section (10) via the outlet pressure chamber (40).

9. Scroll compressor (1) according to claim 5 and 8, characterized in that the outgassing chamber (54) is formed radially outside the outlet pressure chamber (40) and surrounds the outlet pressure chamber (40).

10. Scroll compressor (1) according to any one of the preceding claims, characterized in that the scroll compressor (1) further comprises: a contact pressure chamber (80) to which a contact pressure is applied during compression operation, wherein the orbiting disk (30) is pressed against the stationary disk (20) by the contact pressure; and a second oil return (82) for returning oil from the oil separator (45) to the contact pressure chamber (80).

11. Scroll compressor (1) according to claim 10, characterized in that the second oil return (82) has priority over the direct oil return (50) in case of oil shortage.

12. Scroll compressor (1) according to claim 10 or 11, characterized in that the direct oil return (50) has a first oil inlet (51) opening into the oil separator (45), and that the second oil return (82) has a second oil inlet (81) opening into the oil separator (45), the first oil inlet (51) being arranged above the second oil inlet (81).

13. Scroll compressor (1) according to any one of claims 10 to 12, characterized in that the scroll compressor (1) comprises a reference opening (86), arranged in the compression section (10), and a reference connection (84) forming a fluid connection between the contact pressure chamber (80) and the reference opening (86) for influencing the contact pressure by means of a reference pressure applied to the reference opening (86) during operation.

14. Scroll compressor (1) according to one of the preceding claims, characterized in that the outgassing chamber (54) has a volume in the range from 30 cm3 to 150 cm3.

15. Scroll compressor (1) according to one of the preceding claims, characterized in that an orifice opening (72a) of the fluid return (70) is arranged in a central portion of the compressor channel (26) of the stationary disk (20), the central portion of the compressor channel (26) being composed of all portions of the compressor channel (26) that cannot be in direct fluid communication either with the inlet (11) of the compression section (10) or with the outlet (12) of the compression section (10).