Device for controlling the fluid mass flow of a device for compressing a gaseous fluid and device for compressing a gaseous fluid

Abstract

The invention relates to a device for controlling the fluid mass flow rate of a device for compressing a gaseous fluid and to a device for compressing a gaseous fluid. The device has a housing with a fluid connection acting at different pressure levels, and a closure element arranged such that it can move in translation within the housing along a longitudinal axis and has an active surface assigned to the fluid connection. The closure element is formed to adjust a flow cross-section of a flow path extending between the first fluid connection and the second fluid connection. The housing has a receiving opening for receiving a closure element which is formed from a primary section and a secondary section in an at least two-piece manner. The primary section and the secondary section of the closure element are each guided within the receiving opening of the housing and are each arranged to be completely surrounded by the housing. The device for compressing a gaseous fluid has a device for controlling the mass flow of the fluid.

Description

Technical Field

[0001] The invention relates to a device for controlling a fluid mass flow as a control flow of a device for compressing a gaseous fluid, in particular to a control valve for a scroll compressor. The device for controlling the control mass flow has a housing with a fluid connection subjected to impact at different pressure levels and a closing element, the housing being movable in a translational manner along a longitudinal axis within the housing, having an active surface assigned to the fluid connection. The closing element is formed to adjust the flow cross section of a flow path extending between a first fluid connection and a second fluid connection.

[0002] The invention also relates to a device for compressing a gaseous fluid, in particular a scroll compressor for compressing a refrigerant, having a housing with opposing walls and a compression mechanism having an immovable fixed spiral and a movable orbiting spiral driven via an eccentric drive. Scroll compressors are also called screw compressors. Background Art

[0003] Compressors known in the prior art for mobile applications, in particular for air conditioning systems of motor vehicles for conveying refrigerant through a refrigerant circuit, also referred to as refrigerant compressors, are usually designed as piston compressors with variable displacement or as refrigerant-independent scroll compressors. The compressors are driven via a pulley or are electrically driven.

[0004] In addition to the housing, a conventional scroll compressor also has: an immovable, fixed spiral having a disc-shaped base plate and a spiral wall extending from one side of the base plate; and a movable orbiting spiral also having a disc-shaped base plate and a spiral wall extending from the front side of the base plate. The base plates are arranged relative to each other so that the spiral walls engage each other in the axial direction.

[0005] The fixed spiral and the orbiting spiral work together. The orbiting spiral moves on a circular path by means of an eccentric drive so that the spiral wall contacts at several points and forms several continuous sealed working spaces between the wall and the base plate. The volume sizes of adjacent working spaces are different. Due to the movement of the orbiting spiral relative to the fixed spiral, the volume and position of the working space change so that the volume of the working space gradually becomes smaller toward the center of the spiral wall, and the gaseous fluid enclosed in the working space is compressed. The fluid compressed in this way is discharged from the compression mechanism through at least one outlet. The related increase in pressure in the adjacently arranged working spaces causes a force acting mainly in the axial direction on the orbiting spiral, which also acts eccentrically on the orbiting spiral and thereby generates a tilting moment.

[0006] In addition, the gap formed in the axial direction between the fixed spiral and the orbiting spiral should be minimized to obtain sufficient internal sealing, which is also ensured in connection with pressing the orbiting spiral against the fixed spiral.

[0007] The scroll compressor belonging to the prior art has a wall, which is arranged in the housing and firmly connected to the housing, and the wall forms the boundary of the back pressure area and is therefore also called the opposing wall. Due to the presence of back pressure in the back pressure area also called the back pressure chamber formed between the opposing wall and the orbiting spiral, in particular the back side of the base plate of the orbiting spiral, the orbiting spiral is pressed against the fixed spiral by the force acting in the axial direction, and the fixed spiral is fixed on the housing like the opposing wall. The pressing force acting in the axial direction is regulated by the back pressure existing in the back pressure area, which is also called the contact pressure. Therefore, as an intermediate pressure or medium pressure, the contact pressure level is between the high pressure level as the outlet pressure of the compressor and the low pressure level as the suction pressure of the compressor. The value of the contact pressure is adjusted so that, on the one hand, the axial sealing surface between the orbiting spiral and the fixed spiral is closed, and on the other hand, excessive friction is avoided to cause wear between the fixed spiral and the orbiting spiral.

[0008] The regions in the compressor which are subject to high pressure and back pressure and back pressure and low pressure can each be connected to one another via flow channels with an integrated expansion device. A very limited mass flow of the fluid compressed in the compressor or a mixture of fluid and oil as compressor lubricant flows through the flow channel, which is also referred to as the control mass flow. Conventional expansion devices are each formed as a nozzle. At least one expansion device can also be formed as a spring-loaded mechanical regulating valve.

[0009] DE 10 2016 105 302A1 discloses a control flow regulating valve for a screw compressor in a motor vehicle air conditioning system. The control flow regulating valve has a housing and a closing element arranged inside the housing for adjusting the control flow. The housing is formed with fluid connections for high pressure, back pressure and suction pressure as well as ambient pressure. The closing element for controlling the flow has an effective surface associated with the corresponding fluid connection. The force generated by the pressure applied to the closing element acts on the closing element so that the control flow generating the back pressure flows from the area where the fluid is applied with high pressure to the area where the fluid is applied with suction pressure. In addition, a fluid sealing area to which ambient pressure is applied is formed, and the fluid sealing area is sealed by means of a metal sheet membrane or a vulcanized membrane welded to the metal closing element. A spring element for generating an additional force acting on the closing element is also arranged in the housing.

[0010] The force balance on the closure element and the position of the closure element for achieving the desired control curve of the back pressure as a function of high pressure and suction pressure or low pressure are influenced by the pressure on the active surface and the flow through the channel opening released by the closure element.

[0011] The control flow regulating valve has two elastomer membranes formed on the low-pressure side and the back-pressure side. The elasticity of the elastomer membranes allows the closure element to move axially in the housing. The elastomer membranes delimit an area of ​​the control flow regulating valve in the axial direction which, due to the connection to the ambient pressure, has an atmospheric pressure independent of the low pressure and the back pressure. A fluid-tight and pressure-tight barrier is formed between the low-pressure side and the back-pressure side by the elastomer membranes. The fluid-tight connection of the elastomer membranes is ensured by vulcanization with the surrounding housing or the closure element.

[0012] Devices known in the prior art for controlling the mass flow of a fluid as a control flow, in particular for controlling the mass flow of a fluid as a control flow of a device for compressed gaseous fluids, have a large number of components manufactured in a very precise manner and with low tolerances, which are connected to each other in a complex structure, which leads to a high complexity and a large number of assembly steps during assembly, and thus to high assembly costs. Thus, for example, in order to separate volumes containing fluids of different pressure levels from each other, several seals are also required. The individual elements must be aligned coaxially with each other. A large number of components requires a large installation space, resulting in a high total weight and also a high risk of error during the assembly process. In addition, for example, vulcanizing an elastomeric film on a metal is very difficult and complex to handle and is particularly unsuitable for use in high-pressure applications, such as systems with carbon dioxide as a fluid. Sealing with a vulcanized film also results in a highly permeable surface, which results in a large discharge of the fluid into the environment and thus in a very large loss of the fluid over the entire operating time.

[0013] In order to adjust the device, in particular the closing element, to the corresponding operating point and to achieve high reproducibility, the sealing seat must be embossed. In this case, during embossing, a defined force is applied to the closing element by means of a press, so that a corresponding sealing seat is formed on the housing by plastic deformation of the material. The embossing process usually includes an iteration of embossing steps and tests until the desired pressure level is adjusted, and, for example, according to DE 10 2016 105 302 A1, the embossing process is used to adjust the distance between the closing element and the elastomer membrane in order to eliminate stresses in the elastomer membrane caused by extension. Summary of the invention

[0014] The object of the invention is to provide a device for controlling a fluid mass flow rate as a control flow rate of a device for compressing a gaseous fluid, in particular in order to ensure trouble-free operation and a maximum service life of the device for compressing a fluid. The device should have a minimum number of individual components and should be structurally simple to implement in order also to minimize the assembly effort and costs during assembly. The device requires a minimum installation space, is lightweight and is formed in a fluid-tight manner to prevent leakage or escape of the fluid into the environment and thus prevent fluid losses in the system.

[0015] This object is achieved by the subject matter of the main aspect of the invention. Further developments are indicated in other aspects of the invention.

[0016] This object is achieved by a device according to the invention for controlling a fluid mass flow rate as a control flow rate of a device for compressing a gaseous fluid from a low pressure level to a high pressure level. The device for controlling a fluid mass flow rate comprises a housing having a fluid connection subjected to impact at different pressure levels and a closure element movable in translation along a longitudinal axis within the housing, having an effective surface assigned to the fluid connection. The closure element is formed to adjust the flow cross section of a flow path extending between a first fluid connection and a second fluid connection.

[0017] According to the concept of the invention, the housing has a receiving opening for receiving a closure element, which is formed by a primary section and a secondary section of at least two parts. The primary section and the secondary section of the closure element are each guided in the receiving opening of the housing and are each arranged to be completely surrounded by the housing.

[0018] According to a further improvement of the present invention, the primary section of the closing element is sealed to the housing in a fluid-tight and pressure-tight manner via at least one first sealing element, and the secondary section of the closing element is sealed to the housing in a fluid-tight and pressure-tight manner via at least one second sealing element, in particular via at least two second sealing elements.

[0019] According to an advantageous embodiment of the invention, the housing is formed in at least two parts from a first housing element and a second housing element. The primary section of the closing element is guided in the first housing element and the secondary section of the closing element is guided in the second housing element. The receiving opening of the housing for receiving the closing element is particularly formed to overlap with the housing elements, so that a first area of ​​the receiving opening for receiving the primary section of the closing element is arranged in the first housing element and a second area of ​​the receiving opening for receiving the secondary section of the closing element is arranged in the second housing element.

[0020] According to a preferred design of the present invention, the closing element is formed into a cylindrical shape, in particular a cylindrical shape, with sections having different outer diameters, so that the closing element has a step between adjacent sections. Preferably, the primary section of the closing element is formed with a primary section diameter, and the secondary section of the closing element is formed with at least two sections each having a different outer diameter. The primary section diameter of the primary section of the closing element and the outer diameter of the secondary section may also be different from each other.

[0021] The primary section and the secondary section of the closing element advantageously each have an axis of symmetry which, according to a first alternative embodiment of the invention, is arranged on a common longitudinal axis, or, according to a second alternative embodiment of the invention, is arranged parallel to and spaced apart from one another and parallel to the longitudinal axis.

[0022] An advantage of the invention is that the closure element forms a sealing seat on the first end face, in particular on the first end face of the primary section, which is sealed with the housing, in particular with the first housing element.

[0023] The primary section of the closing element is preferably aligned by a second end face, which is distal to the first end face, points towards the first end face of the secondary section of the closing element and advantageously rests against the first end face of the secondary section of the closing element.

[0024] According to another advantageous design of the invention, a volume limited by a housing and a closing element having an annular effective surface having as an inner diameter a primary section diameter of the closing element, in particular a primary section diameter of the primary section of the closing element, and a first outer diameter of the closing element, in particular a first outer diameter of the secondary section of the closing element, is acted upon by a fluid at a low pressure level and is connected to a third fluid connection of the housing.

[0025] The volume defined by the housing, in particular the second housing element, and the second end face of the closing element located distal to the first end face, in particular the second end face of the secondary section of the closing element, is preferably subjected to the ambient pressure level, in particular the ambient air, and is connected to the environment via a fourth fluid connection of the housing.

[0026] In addition, the volume limited by the housing and the closing element having the following annular effective surface is advantageously exposed to the action of the fluid at a back pressure level and is connected to the first fluid connection of the housing: the annular effective surface has the second outer diameter of the closing element as an inner diameter and the first outer diameter of the closing element, the first outer diameter and the second outer diameter each being in particular the first outer diameter and the second outer diameter of a secondary section of the closing element.

[0027] According to a further improvement of the present invention, a first fluid connection is formed inside the housing, which extends from the first fluid connection to a volume limited by the housing and a closing element having the following annular effective surface: the annular effective surface has the second outer diameter of the closing element as the inner diameter and the first outer diameter of the closing element, the first outer diameter and the second outer diameter are each specifically the first outer diameter and the second outer diameter of a secondary section of the closing element.

[0028] In the housing, a second fluid connection can also be arranged, which extends from the first fluid connection to a volume limited by the housing and a closing element having an annular effective surface with the primary section diameter of the closing element, in particular the primary section diameter of the primary section of the closing element, and the first outer diameter of the closing element, in particular the first outer diameter of the secondary section of the closing element, or a third fluid connection extending from the first fluid connection to the housing. The second fluid connection is advantageously formed with an expansion element, in particular a throttling member.

[0029] The device for controlling the mass flow of a fluid as a control flow is advantageously configured such that the translational movement of the closing element, in particular the primary section and the secondary section, in the housing, in particular the first housing element and the second housing element, is based solely on the pressure acting on the effective surface of the closing element and thus on the pressing force. The defined pressing force or piston force causes the movement of the closing element in the sliding sealing element, in particular the sealing element formed as an O-ring. The primary section and the secondary section of the closing element can each be a metallic or non-metallic component.

[0030] According to another advantageous embodiment of the invention, the first fluid connection of the housing is subjected to the action of the fluid at a back pressure level, and the second fluid connection of the housing is subjected to the action of the fluid at a high pressure level, while the third fluid connection of the housing is subjected to the action of the fluid at a low pressure level. The back pressure level represents an intermediate pressure level between the low pressure level and the high pressure level of the fluid. The fourth fluid connection of the housing is preferably subjected to the action of the ambient pressure level, in particular the ambient air.

[0031] According to another preferred embodiment of the invention, the device for filtering various particles from a fluid has a filter element which is integrated into the closure element, in particular into the primary section of the closure element, or is arranged as a separate element in the flow opening of the second fluid connection and is therefore arranged in each case at the inlet of the device.

[0032] The object is also achieved by a device for compressing a gaseous fluid from a low pressure level to a high pressure level according to the invention, in particular a scroll compressor for compressing a refrigerant. The fluid to be compressed is present at a low pressure level in an inlet region, and the compressed fluid is present at a high pressure level in a high pressure region, in particular at the outlet of the device for compression. The device for compression has a housing with opposing walls and a compression mechanism, which has an immovable fixed spiral and a movable orbiting spiral driven via an eccentric drive. The housing with opposing walls and the orbiting spiral at least partially surround a back-pressure chamber together. In addition, a flow path extending from the high pressure region to the back-pressure chamber is formed in the housing.

[0033] According to the concept of the invention, the device for controlling the mass flow of a fluid according to the invention is formed in the flow path extending between the high pressure area and the back pressure chamber. Therefore, the device for controlling the mass flow of a fluid as a control flow regulating valve is preferably arranged to be integrated in the housing of the compressor. Therefore, the device for controlling the mass flow of a fluid is formed without an additional housing.

[0034] According to a further development of the invention, the housing has at least two housing elements, a first housing element for receiving a primary section of a closure element of the device for controlling a fluid mass flow and a second housing element for receiving a secondary section of the closure element of the device for controlling a fluid mass flow.

[0035] The closing element is arranged in the housing by means of a primary section and a secondary section so as to be movable in a translational manner, thereby opening and closing the flow path. When the flow path is opened, the fluid expands from a high pressure level to a desired back pressure level. The level of back pressure is determined by the position of the closing element, in particular the position of the primary section of the closing element, and thus by the degree of opening of the device for controlling the mass flow of the fluid. The position of the closing element is adjusted by a force balance at the active surface of the closing element, which is obtained from different pressure levels acting on the active surface.

[0036] The closure element of the device for controlling a fluid mass flow is advantageously arranged in a receiving opening formed in the housing of the device for compressing a gaseous fluid. The primary section of the closure element is arranged in a first region of the receiving opening formed in the first housing element, and the secondary section of the closure element is arranged in a second region of the receiving opening formed in the second housing element, in particular so that the closure element can be moved in a translational manner along the longitudinal axis.

[0037] An advantageous design of the invention allows the device for compressing a gaseous fluid with a device for controlling the mass flow of the fluid to be used as a compressor in a refrigerant circuit of an air conditioning system of a motor vehicle. The compressor can be designed as an electric drive or a mechanical drive. In this case, the compression mechanism is driven by means of an electric motor or a pulley.

[0038] The device according to the invention for controlling a fluid mass flow as a control flow of a device for compressing a gaseous fluid from a low pressure level to a high pressure level can therefore be formed as a control flow regulating valve, in particular a control flow regulating valve of a scroll compressor of a refrigerant circuit of an air-conditioning system of a motor vehicle.

[0039] The device according to the invention for controlling the mass flow of a fluid and the device for compressing a gaseous fluid having the device according to the invention for controlling the mass flow of a fluid have various other advantages:

[0040] - The number of individual components is minimal, the structure is simple, and the durability is high, so the assembly workload, manufacturing workload, and maintenance workload are minimized, and the assembly cost, manufacturing cost, and maintenance cost are the lowest,

[0041] - for example, by means of a two-piece design of the closing element, the coaxiality otherwise required in the device is reduced, no spring element is required in the device in comparison with the prior art, and the sealing seat is integrated into the receiving element without an additional forming step,

[0042] -Minimum installation space and minimum total weight,

[0043] -The device has a purely mechanical structure with automatic control inside, and

[0044] - Maximum operational safety and tightness due to the minimum number of potential leakage paths to the environment - there is only one sealing point to the environment, so the release of fluids, in particular of refrigerant in the device used for compression, is minimal. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Further details, features and advantages of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings, in which:

[0046] Figure 1 is a basic circuit diagram of a device for controlling a fluid mass flow rate by using radial ambient pressure in the prior art, the fluid mass flow rate being used as a control flow rate of a device for compressing a gaseous fluid,

[0047] Figure 2 and Figure 3Each is a basic circuit diagram of a device for controlling a fluid mass flow rate as a control flow rate of a device for compressing a gaseous fluid according to the present invention, and

[0048] Figure 4 is a transverse cross-sectional view of a device for compressing a gaseous fluid, the device having an integrated device for controlling the mass flow rate of the fluid as a control flow rate. DETAILED DESCRIPTION

[0049] Figure 1 The basic circuit diagram of a device 1' in the prior art for controlling a fluid mass flow rate by application of radial ambient pressure, also known as a control flow regulating valve, is shown, which serves as a control flow of a device for compressing a gaseous fluid from a suction pressure level to a high pressure level.

[0050] The device 1' has a housing 2', which has different fluid connections 2a', 2b', 2c', 2d'. Within the housing 2', a closing element 3' is arranged to be movable in a translational manner along a longitudinal axis 3a, which corresponds to the axis of symmetry of the closing element 3'. The device 1' is formed with a flow path extending from a first fluid connection 2a' to a second fluid connection 2b', and the flow cross section of the flow path can be adjusted by means of the closing element 3'. The controlled mass flow of the fluid is adjusted from the high pressure level at the second fluid connection 2b' to the back pressure level at the first fluid connection 2a' by means of the closing element 3'.

[0051] In addition, the housing 2' has a third fluid connector 2c' and a fourth fluid connector 2d', the fluid of the third fluid connector 2c' is at the suction pressure level of the device for compressing the fluid, which suction pressure level is also called the low pressure level, and the fluid of the fourth fluid connector 2d' is at the ambient pressure level. Neither the third fluid connector 2c' nor the fourth fluid connector 2d' forms a flow path. The third fluid connector 2c' and the fourth fluid connector 2d' are used to transmit the suction pressure level and the ambient pressure level to the corresponding effective surface of the closed element 3'.

[0052] Between the closing element 3' and the housing 2', a membrane sealing element 4' is arranged, which delimits the area of ​​the device 1' in the direction of the longitudinal axis 3a and seals the device 1' to the ambient pressure. Due to the connection to the ambient pressure level, the area delimited by the membrane sealing element 4' has an atmospheric pressure that is independent of the low pressure and the back pressure. The membrane sealing element 4' forms a fluid-tight and pressure-tight barrier in combination between the low-pressure side connected to the third fluid connection 2c' and the back-pressure side connected to the first fluid connection 2a'.

[0053] Since the membrane sealing elements 4' formed between the closing element 3' and the housing 2' are each formed as welded sheet metal membranes or vulcanized membranes, there is a high risk of leakage and thus a risk of fluid flowing out into the environment via the fourth fluid connection 2d'. The device 1' has four potential leakage paths for fluid to leak into the environment. Each membrane sealing element 4' formed of an elastomer is vulcanized onto the closing element 3'.

[0054] exist Figure 1 In the closed position of the device 1' shown in the figure, the closing element 3' rests against a sealing seat 6 formed on the housing 2', and the sealing seat 6 has a sealing seat diameter d1. The sealing seat 6 is formed between the first fluid connection 2a' and the second fluid connection 2b'. The flow path extending between the fluid connections 2a', 2b' is closed. In the case where the position of the device 1' deviates from the closed position, the fluid flows from the second fluid connection 2b' to the first fluid connection 2a' through the flow path. The flow resistance is generated by the adjusted narrow sealing seat 6, which causes a pressure loss of the fluid.

[0055] The device 1' also has a spring element 5', which is arranged to act on the closing element 3' with a spring force aligned counter to the closed position of the closing element 3'. Therefore, the spring element 5' is formed to open the device 1', in particular the flow path extending between the first fluid connection 2a' and the second fluid connection 2b', when the forces acting on the closing element 3' due to different pressures are balanced.

[0056] The closing element 3' is supported against the sealing seat 6 by the free end face of the primary section 3-1' oriented in the direction of the longitudinal axis 3a in such a way as to close the flow path extending between the first fluid connection 2a' and the second fluid connection 2b'. The primary section 3-1' of the closing element 3' cooperates with the sealing seat 6 and the second fluid connection 2b'.

[0057] The geometry of the closing element 3' is formed such that the primary section diameter d2, the sealing seat diameter d1, the first effective diameter d3' from the suction pressure level to the ambient pressure level, and the second effective diameter d4' from the back pressure level to the ambient pressure level are configured such that the forces generated act on the closing element 3' depending on the pressure level applied in each case and thus control the mass flow of the fluid from the second fluid connection 2b' to the first fluid connection 2a'. By means of force balancing, the closing element 3' is brought into the corresponding position in each case.

[0058] The device 1' is also formed with a first fluid connection 7, which extends from the first fluid connection 2a' to the following volume: the volume is enclosed by the housing 2' and the closing element 3', in particular, with an effective surface of a second effective diameter d4' from the back pressure level to the ambient pressure level, so that the back pressure level is correspondingly included in the force balance at the closing element 3'. In addition, a second fluid connection 8 is also provided, which connects the first fluid connection 2a' to the third fluid connection 2c' and extends between the first fluid connection 2a' and the following volume: the volume is enclosed by the housing 2' and the closing element 3', in particular, with an effective surface of a first effective diameter d3' from the suction pressure level to the ambient pressure level. An expansion element 9, in particular a throttling element or a throttle valve, is arranged in the second fluid connection 8.

[0059] The primary section 3 - 1 ′ of the closure element 3 ′ is sealed off from the housing 2 ′ by means of a sealing element 10 ′ in the form of an O-ring.

[0060] exist Figure 2 and Figure 3 In the figure, the basic circuit diagram of the device 1 according to the invention for controlling the mass flow of a fluid by the application of the axial ambient pressure on one end face of a piston-shaped closing element 3 in a housing 2 is shown, which serves as the control flow of a device for compressing a gaseous fluid from a suction pressure level to a high pressure level. Figure 1 Compared to the prior art device 1 ′ shown in FIG. 1 , identical parts are provided with the same reference numerals.

[0061] The device 1 has a housing 2 which comprises different fluid connections 2a, 2b, 2c, 2d. Fluid connections 2a, 2b, 2c, 2d are also to be understood as meaning flow channels formed in components of the device 1.

[0062] The closure element 3 is incorporated in the housing 2 and can be moved in a translational manner along a longitudinal axis 3a which is an axis of symmetry of the closure element 3. The closure element 3 is arranged in a receiving opening 11 formed in the housing 2. Figure 3 It can be seen that the two-part closure element 3 with the primary section 3-1 is arranged to be guided in the first housing element 2-1, in particular in the first region 11-1 of the receiving opening 11, and the two-part closure element 3 with the secondary section 3-2 is arranged to be guided in the second housing element 2-2, in particular in the second region 11-2 of the receiving opening 11. The housing 2 is divided into two parts or is formed in two parts by the first housing element 2-1 and the second housing element 2-2.

[0063] The primary section 3-1 as a piston and the secondary section 3-2 as an actuator, also referred to as a control element, each have a cylindrical shape, in particular a cylindrical shape, with sections of different outer diameters. The primary section 3-1 and the secondary section 3-2 can be made of the same material or different materials, such as metal or non-metal, in particular plastic.

[0064] The device 1 has a flow path extending between a first fluid connection 2a at the back pressure level of the device for compressing a gaseous fluid and a second fluid connection 2b at the high pressure level, the flow cross section of which flow path can be adjusted by the movement of the closing element 3, in particular the movement of the primary section 3-1 of the closing element 3. The controlled mass flow of the fluid through the flow path is adjusted by the closing element 3. The flow path is formed in the first housing element 2-1.

[0065] The free first end face of the primary section 3-1 of the closing element 3, which is oriented in the direction of the longitudinal axis 3a, bears against the sealing seat 6 in such a way as to close the flow path extending between the first fluid connection 2a and the second fluid connection 2b. The sealing seat 6 is formed in the form of a step or an edge in the first housing element 2-1 of the housing 2 of the device 1. The primary section 3-1 of the closing element 3 cooperates with the sealing seat 6 and the second fluid connection 2b.

[0066] The housing 2 also has a third fluid connection 2c and a fourth fluid connection 2d, the fluid of the third fluid connection 2c is at the suction pressure or low pressure level of the device for compressing the fluid, and the fluid of the fourth fluid connection 2d is at the ambient pressure level. The third fluid connection 2c and the fourth fluid connection 2d are only used to transmit the suction pressure level and the ambient pressure level to the corresponding effective surface of the closing element 3.

[0067] The sealing elements 10 - 1 , 10 - 2 are arranged between the housing 2 and the closing element 3 . Figure 3 A first sealing element 10-1 is arranged in a first area 11-1 of a receiving opening 11 between a first housing element 2-1 and a primary section 3-1 of a closing element 3, and two second sealing elements 10-2 are arranged in a second area 11-2 of the receiving opening 11 between a second housing element 2-2 and a secondary section 3-2 of the closing element 3, the two second sealing elements 10-2 each defining a volume of the device 1 and sealingly isolating these volumes from each other, wherein these volumes are subjected to different pressures in the direction of the longitudinal axis 3a.

[0068] The primary section 3 - 1 of the closing element 3 rests with a second end face on a first end face of the secondary section 3 - 2 of the closing element 3 , which second end face is oriented in the direction of the longitudinal axis 3 a and is located distally from the first end face.

[0069] The piston-shaped secondary section 3-2 of the closing element 3 is subjected to the ambient pressure at a second end face, which is oriented in the direction of the longitudinal axis 3a and is located distally to the first end face facing the primary section 3-1 and the sealing seat 6. The volume bounded by the housing 2, in particular the second housing element 2-2, and the second end face of the secondary section 3-2 of the closing element 3 is subjected to the ambient pressure level. Therefore, the volume connected to the environment via the fourth fluid connection 2d has a pressure level that is independent of the low pressure level and the back pressure level.

[0070] After filling the device for compressing a gaseous fluid and therefore also after filling the device 1 for controlling a fluid mass flow of a refrigerant, the primary section 3 - 1 and the secondary section 3 - 2 of the closure element 3 are always in mechanical contact due to the forces acting on the closure element 3 .

[0071] In the closed position of the device 1, the closure element 3 with the primary section 3-1 rests against a sealing seat 6 with a sealing seat diameter d1 formed on the housing 2, in particular the first housing element 2-1. The flow path extending between the first fluid connection 2a and the second fluid connection 2b is closed.

[0072] The geometry of the closing element 3 is formed such that the primary section diameter d2 of the primary section 3-1 of the closing element 3, the sealing seat diameter d1, the first outer diameter d3 from the suction pressure level to the back pressure level and the second outer diameter d4 from the back pressure level to the ambient pressure level are configured such that the forces generated act on the closing element 3 according to the respectively applied pressures and thus control the controlled mass flow of the fluid from the second fluid connection 2b to the first fluid connection 2a. By means of force balance, the closing element 3 is brought into the corresponding position in each case. The primary section diameter d2 of the primary section 3-1 of the closing element 3 and the outer diameters d3, d4 of the secondary section 3-2 are configured such that the established back pressure level particularly meets the required pressure of the orbiting spiral on the fixed spiral of the compression mechanism of a scroll compressor as a device for compressing gaseous fluids.

[0073] The device 1 is also formed with a first fluid connection 7, which extends from the first fluid connection 2a to the following volume: the volume is enclosed by the housing 2 and the closing element 3, in particular with an effective surface of the first outer diameter d3 from the back pressure level to the suction pressure level, so as to include the back pressure level in the force balance at the closing element 3. In addition, a second fluid connection 8 is provided, which connects the first fluid connection 2a to the third fluid connection 2c and extends between the first fluid connection 2a and the following volume: the volume is enclosed by the housing 2 and the closing element 3, in particular with an effective surface of the first effective diameter d3 from the suction pressure level to the back pressure level. The expansion element 9 is arranged in the second fluid connection 8.

[0074] The following volume is used to reduce the effective surface of the back pressure acting in the closed position of the closing element 3: this volume is enclosed by the second end face of the secondary section 3-2 of the closing element 3 including an effective surface with a second outer diameter d4 and the housing 2, in particular the second housing element 2-2 and is connected to the fourth fluid connection 2d and is therefore subject to the ambient pressure level.

[0075] On the first end face of the primary section 3-1 of the closing element 3, the high pressure level existing in the second fluid connection 2b and the reduced back pressure level existing at the sealing seat 6 by means of the sealing gap formed between the primary section 3-1 of the closing element 3 and the housing 2, in particular the first housing element 2-1, also act in the opposite direction to the closed position of the closing element 3.

[0076] The first fluid connector 2a is formed so that the housing element overlaps the first fluid connector 7, while the second fluid connector 2b extends in the first housing element 2-1, and the fourth fluid connector 2d extends in the second housing element 2-2. The third fluid connector 2c can be formed in the first housing element 2-1 or in the second housing element 2-2.

[0077] The purpose of forming the corresponding diameter of the closing element 3 is to establish a balance of forces in a manner that adjusts the back pressure level. The back pressure at the circular effective surface of the secondary section 3-2 with the first outer diameter d3 and the second outer diameter d4 generates a force directed in the closing direction of the closing element 3, while the suction pressure at the circular effective surface of the secondary section 3-2 with the first outer diameter d3 and the section with the primary section diameter d2 plus the high pressure at the circular effective surface with the sealing seat diameter d1 generates a reaction force directed opposite to the closing direction of the closing element 3. The reaction force is represented by means of the coefficient x of the suction pressure and the coefficient y of the high pressure.

[0078] “Back pressure = x·suction pressure + y·high pressure”.

[0079] The coefficients x and y are suitable for setting the curve of the required or desired back pressure as a function of the variation of the planes on which the respective pressure acts. The coefficients adapt to the variation of the ratio of the pressure-exposed surfaces to one another, so that a variation of the coefficients results in a variation of the surface ratio and therefore in a variation of the set back pressure as a function of the degree of opening of the device for controlling the mass flow of a fluid.

[0080] With the translational movement of the closing element 3, in particular the primary section 3-1, a throttling gap is provided between the sealing seat 6 and the primary section 3-1 and the housing 2, in particular the first housing element 2-1, wherein the fluid is reduced from the high pressure level to the corresponding back pressure level when flowing through the throttling gap. The primary section 3-1 and the secondary section 3-2 of the closing element 3 can be aligned along the longitudinal axis 3a as the axis of symmetry and thus coaxially aligned, or can be aligned eccentrically with respect to the longitudinal axis 3a and thus parallel to each other and spaced apart.

[0081] The first sealing element 10-1 formed as an O-ring forms a fluid-tight and pressure-tight barrier between the volume impacted by the suction pressure level and the first fluid connection 2a, while the second sealing element 10-2 formed as an O-ring forms a fluid-tight and pressure-tight barrier between the volumes impacted by the ambient pressure level and the back pressure level and between the volumes impacted by the back pressure level and the suction pressure level. Therefore, the second sealing element 10-2, which is only arranged between the volumes impacted by the ambient pressure level and the back pressure level, forms a seal of the device 1 to the environment.

[0082] exist Figure 4 , a transverse cross-sectional view of a device for compressing a gaseous fluid, in particular an electrically driven compressor 20, in particular a scroll compressor, is shown, the device having a combined device 1 for controlling a fluid mass flow as a control flow. The compressor 20 is formed by a compression mechanism 21 and an electric motor 22 for driving the compression mechanism 21.

[0083] The compression mechanism 21 formed by the fixed spiral 21a and the orbiting spiral 21b and the electric motor 22 are arranged in the volume enclosed by the housing 2. The housing 2 is formed by three housing elements 2-1, 2-2, 2-3, in particular, a first housing element 2-1 for receiving the primary section 3-1 of the closing element 3 and the compression mechanism 21, a second housing element 2-2 for receiving the secondary section 3-2 of the closing element 3, and a third housing element 2-3 for receiving the electric motor 22, and the housing 2 is preferably formed of metal, such as aluminum.

[0084] The electric motor 22 has a stator 22a having a substantially hollow cylindrical stator core and a coil wound on the stator core, and a rotor 22b arranged inside the stator 22a. When electric energy is supplied to the coil of the stator 22a, the rotor 22b is set to rotate. The rotor 22b is coaxially arranged inside the stator 22a and can rotate around the rotation axis 23. The drive shaft 24 may be formed integrally with the rotor 22b or as a separate element.

[0085] An orbiting spiral 21 b of the compression mechanism 21, in which a gaseous fluid, in particular a refrigerant, is compressed, is driven via a drive shaft 24 connected to a rotor 22 b of an electric motor 22. The fluid compressed to a high pressure level when flowing through the compression mechanism 21 is discharged from the compression mechanism 21 into a region 20 b of a high pressure level of the compressor 20 through at least one outlet 25.

[0086] The compressor 20 also has a wall arranged in the housing 2, in particular the second housing element 2-2 and fixedly connected to the housing 2, which wall forms a boundary of a region 20a of the backpressure level of the compressor 20, also referred to as the backpressure region, and is therefore also referred to as an opposing wall 26. In the region 20a of the backpressure level formed between the opposing wall 26 and the orbiting spiral 21b, in particular the rear side of the base plate of the orbiting spiral 21b, the fluid is at a backpressure level, which also exists as a contact pressure level, which exists as an intermediate pressure between a high pressure level, which is the outlet pressure of the compressor 20, and a low pressure level, which is the suction pressure of the compressor 20. The fluid has a low pressure level in a region 20c of the low pressure level of the compressor 20, in which the electric motor 22 is also arranged. Outside the housing 2 of the compressor 20, there is an ambient pressure, which is therefore also designated as a region 20d of the ambient pressure level of the compressor 20.

[0087] The device 1 for controlling a fluid mass flow is combined with a closing element 3 in a receiving opening 11 as a cavity of a housing 2 of a device for compressing a gaseous fluid, in particular a compressor 20. A primary section 3-1 of the closing element 3 is arranged in a first region 11-1 of the receiving opening 11 formed in a first housing element 2-1, and a secondary section 3-2 of the closing element 3 is arranged in a second region 11-2 of the receiving opening 11 formed in a second housing element 2-2.

[0088] A first sealing element 10-1 formed as an O-ring is arranged between the primary section 3-1 of the closing element 3 and the first housing element 2-1, and a second sealing element 10-2 formed as an O-ring is arranged between the secondary section 3-2 of the closing element 3 and the second housing element 2-2 and seals and isolates the corresponding pressure spaces from each other.

[0089] The first sealing element 10-1 forms a fluid-tight and pressure-tight barrier between the volumes affected by the suction pressure level and the back pressure level, in particular, between the low-pressure level area 20c of the compressor 20 and the back-pressure level area 20a, while the second sealing element 10-2 forms a fluid-tight and pressure-tight barrier between the volumes affected by the suction pressure level and the back pressure level, in particular, between the low-pressure level area 20c of the compressor 20 and the back-pressure level area 20a, and between the volumes affected by the back pressure level and the ambient pressure level, in particular, between the back-pressure level area 20a of the compressor 20 and the ambient pressure level area 20d.

[0090] Reference numerals

[0091] 1,1' device

[0092] 2,2' Shell

[0093] 2-1 First housing element

[0094] 2-2 Second shell element

[0095] 2-3 The third shell element

[0096] 2a, 2a' First fluid connection at back pressure level

[0097] 2b, 2b' Second fluid connection at high pressure level

[0098] 2c, 2c' Third fluid connection at low pressure / suction pressure level

[0099] 2d, 2d' Fourth fluid connection at ambient pressure level

[0100] 3,3' Closure element

[0101] 3a Longitudinal axis

[0102] 3-1, 3-1' Primary section of closing element 3, 3'

[0103] 3-2 Secondary section of closing element 3

[0104] 4' membrane sealing element

[0105] 5' Spring element

[0106] 6 Sealing seat

[0107] 7 First fluid connection

[0108] 8 Second fluid connection

[0109] 9 Expansion element

[0110] 10-1 First sealing element

[0111] 10-2 Second sealing element

[0112] 10' Sealing element

[0113] 11 Accepting the opening

[0114] 11-1 First area of ​​receiving opening 11

[0115] 11-2 Second area of ​​receiving opening 11

[0116] 20 Compressor

[0117] 20a Area of ​​back pressure level

[0118] 20b Areas with high pressure levels

[0119] 20c Area of ​​low pressure / suction pressure level

[0120] 20d Area of ​​ambient pressure level

[0121] 21 Compression mechanism

[0122] 21a Fixing screw

[0123] 21b Orbiting spiral

[0124] 22 Electric Motor

[0125] 22a Stator

[0126] 22b Rotor

[0127] 23 Rotation axis

[0128] 24 Drive shaft

[0129] 25 Exit

[0130] 26 Opposing wall

[0131] d1 Sealing seat diameter

[0132] d2 Primary section diameter

[0133] d3 first outer diameter

[0134] d3' first effective diameter

[0135] d4 Second outer diameter

[0136] d4' Second effective diameter.

Claims

1. A device (1) for controlling the mass flow of a fluid in a device for compressing a gaseous fluid from a low pressure level to a high pressure level, the device (1) comprising a housing (2) having fluid connections (2a, 2b, 2c, 2d) acted upon at different pressure levels and a closure element (3), the housing (2) having fluid connections (2a, 2b, 2c, 2d) being arranged in the housing (2) so as to be movable in translation along a longitudinal axis (3a) and having an effective surface associated with the fluid connections (2a, 2b, 2c, 2d), wherein: The closing element (3) is formed to control the flow cross section of a flow path extending between a first fluid connection (2a) and a second fluid connection (2b), and is characterized in that the housing (2) has a receiving opening (11) for receiving the closing element (3), and the closing element (3) is formed in at least two parts by a primary section (3-1) and a secondary section (3-2), wherein the primary section (3-1) and the secondary section (3-2) of the closing element (3) are each guided in the receiving opening (11) of the housing (2) and are each arranged to be completely surrounded by the housing (2).

2. The device (1) according to claim 1, characterized in that The primary section (3-1) of the closing element (3) is sealed to the housing (2) in a fluid-tight and pressure-tight manner via at least one first sealing element (10-1), and the secondary section (3-2) of the closing element (3) is sealed to the housing (2) in a fluid-tight and pressure-tight manner via at least one second sealing element (10-2), in particular via at least two second sealing elements (10-2).

3. The device (1) according to claim 1 or 2, characterized in that The housing (2) is formed in at least two parts by a first housing element (2-1) and a second housing element (2-2), wherein the primary section (3-1) of the closing element (3) is arranged to be guided in the first housing element (2-1), and the secondary section (3-2) of the closing element (3) is arranged to be guided in the second housing element (2-2).

4. The device (1) according to any one of claims 1 to 3, characterized in that The closure element (3) is formed in a cylindrical shape, in particular a circular cylindrical shape, having sections with different outer diameters.

5. The device (1) according to claim 4, characterized in that The primary section (3-1) of the closing element (3) is formed with a primary section diameter (d2), and the secondary section (3-2) of the closing element (3) is formed with at least two sections having respectively different outer diameters (d3, d4).

6. The device (1) according to claim 4 or 5, characterized in that The primary section (3-1) and the secondary section (3-2) of the closing element (3) each have an axis of symmetry which is arranged on the common longitudinal axis (3a) or is parallel to each other and spaced apart and parallel to the longitudinal axis (3a).

7. The device (1) according to any one of claims 4 to 6, characterized in that The closure element (3) forms a sealing seat (6) on a first end face, in particular on a first end face of the primary section (3-1), which is sealed with the housing (2), in particular with the first housing element (2-1).

8. The device (1) according to claim 7, characterized in that The primary section (3-1) of the closing element (3) is aligned via a second end face, which is located distally from the first end face and points to the first end face of the secondary section (3-2) of the closing element (3), and is particularly arranged to rest against the first end face of the secondary section (3-2) of the closing element (3).

9. The device (1) according to any one of claims 5 to 8, characterized in that The volume defined by the housing (2) and the closing element (3) having the following annular effective surface is subjected to the action of the fluid at the low pressure level and forms a third fluid connection (2c) connected to the housing (2): the annular effective surface has the primary section diameter (d2) of the closing element (3), in particular the primary section diameter (d2) of the primary section (3-1) of the closing element (3), as an inner diameter, and the first outer diameter (d3) of the closing element (3), in particular the first outer diameter (d3) of the secondary section (3-2) of the closing element (3).

10. Device (1) according to claims 7 to 9, characterized in that The volume defined by the housing (2), in particular the second housing element (2-2), and the second end face of the closing element (3) located distal to the first end face, in particular the second end face of the secondary section (3-2) of the closing element (3), is subjected to the ambient pressure level and is formed to be connected to the environment via a fourth fluid connection (2d) of the housing (2).

11. The device (1) according to any one of claims 5 to 10, characterized in that The volume defined by the housing (2) and the closing element (3) having the following annular effective surface is subjected to the action of a fluid at a back pressure level and forms the first fluid connection (2a) connected to the housing (2): the annular effective surface has the second outer diameter (d4) of the closing element (3) as an inner diameter and the first outer diameter (d3) of the closing element (3), the first outer diameter and the second outer diameter being respectively the first outer diameter and the second outer diameter of the secondary section (3-2) of the closing element (3).

12. The device (1) according to claim 11, characterized in that A first fluid connection (7) is formed, which extends from the first fluid connection (2a) to the volume defined by the housing (2) and the closing element (3) having the following annular effective surface: the annular effective surface has the second outer diameter (d4) of the closing element (3) and the first outer diameter (d3) of the closing element (3) as the inner diameter, the first outer diameter and the second outer diameter are respectively, in particular, the first outer diameter and the second outer diameter of the secondary section (3-2) of the closing element (3).

13. Device (1) according to claims 9 to 12, characterized in that A second fluid connection (8) is formed, which extends from the first fluid connection (2a) to a volume defined by the housing (2) and the closing element (3) having the following annular effective surface: the annular effective surface has the primary section diameter (d2) of the closing element (3), in particular the primary section diameter (d2) of the primary section (3-1) of the closing element (3), as an inner diameter, and the first outer diameter (d3) of the closing element (3), in particular the first outer diameter (d3) of the secondary section (3-2) of the closing element (3).

14. The device (1) according to claim 13, characterized in that An expansion element (9), in particular a throttle component, is arranged in the second fluid connection (8).

15. The device (1) according to any one of claims 1 to 14, characterized in that The sealing elements (10-1, 10-2) are each formed as an O-ring seal.

16. The device (1) according to any one of claims 1 to 15, characterized in that The first fluid connection (2a) of the housing (2) is formed to be acted upon by a fluid at a back pressure level, and the second fluid connection (2b) of the housing (2) is formed to be acted upon by a fluid at the high pressure level.

17. The device (1) according to any one of claims 1 to 16, characterized in that The third fluid connection (2c) of the housing (2) is formed to be acted upon by the fluid at the low pressure level.

18. The device (1) according to any one of claims 1 to 17, characterized in that The fourth fluid connection (2d) of the housing (2) is formed to be subjected to the ambient pressure level.

19. A device for compressing a gaseous fluid from a low pressure level to a high pressure level, in particular a compressor (20), in particular a scroll compressor, comprising a housing (2) with opposing walls (26) and a compression mechanism (21), the compression mechanism (21) having an immovable fixed spiral (21a) and a movable orbiting spiral (21b) driven via an eccentric drive, wherein: The shell (2) having the opposing walls (26) and the orbiting spiral (21b) are formed to enclose a back-pressure chamber at least in certain areas, and a flow path extending from a high-pressure area to the back-pressure chamber is formed in the shell (2), characterized in that a device (1) for controlling the mass flow rate of a fluid according to any one of claims 1 to 18 is formed in the flow path extending between the high-pressure area and the back-pressure chamber.

20. The device according to claim 19, characterized in that The housing (2) has at least two housing elements (2-1, 2-2, 2-3), wherein the first housing element (2-1) is formed to receive a primary section (3-1) of the closing element (3) of the device (1) for controlling the mass flow of the fluid, and the second housing element (2-2) is formed to receive a secondary section (3-2) of the closing element (3) of the device (1) for controlling the mass flow of the fluid.

21. The device according to claim 20, characterized in that The closing element (3) of the device (1) for controlling the mass flow of the fluid is arranged in a receiving opening (11) formed in the shell (2) of the device for compressing the gaseous fluid, wherein the primary section (3-1) of the closing element (3) is arranged in a first area (11-1) of the receiving opening (11) formed in the first shell element (2-1), and the secondary section (3-2) of the closing element (3) is arranged in a second area (11-2) of the receiving opening (11) formed in the second shell element (2-2), and the closing element is particularly capable of moving in a translational manner along a longitudinal axis.

22. Use of a device for compressing a gaseous fluid with a device (1) for controlling the mass flow of a fluid according to any one of claims 19 to 21 in a refrigerant circuit of an air-conditioning system of a motor vehicle.

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