ES3046134T3 - Thermal deformation management in a scroll plate of a scroll compressor - Google Patents

Abstract

A spiral plate, for use in a spiral compressor, comprises a base plate (200) with a first side (205) and a second side (210), wherein the second side is opposite the first, and a spiral (270) formed on the first side of the base plate. This base plate comprises one or more recesses (220), and an insulating material (260) is located in at least one of these recesses. A spiral compressor with its corresponding plate is described.

Description

[0001] DESCRIPTION

[0003] Management of thermal deformation in a scroll plate of a scroll compressor

[0005] The present application relates to a scroll plate for use in a scroll compressor, wherein said compressor can be used, for example, in refrigeration systems.

[0007] A compressor is a device that reduces the volume of a fluid by increasing the pressure of the fluid.

[0009] Compressors are used, for example, in refrigeration systems. In a typical refrigeration system, a refrigerant circulates through a refrigeration cycle. As it circulates, the refrigerant undergoes changes in its thermodynamic properties in different parts of the refrigeration system and transfers heat from one part of the system to another. The refrigerant is a fluid, that is, a liquid, vapor, or gas. Examples of refrigerants include synthetic refrigerants, such as fluorocarbons. However, in recent applications, the use of carbon dioxide, CO₂, a non-synthetic refrigerant, has become increasingly important because it is not harmful to the environment.

[0011] A compressor comprises at least a suction port, a discharge port, and a compression medium. At the suction port, the compressor receives the fluid to be compressed. If the compressor is used in a refrigeration system, the fluid is a refrigerant. At the suction port, the fluid is generally in a gaseous or vapor state. The compression medium is used to compress the fluid from an initial pressure, for example, the pressure of the fluid at the suction port, to a desired discharge pressure. For example, the compression medium may form at least one compression chamber. A compression chamber is a closed volume in which a portion of the refrigerant is compressed. Subsequently, the compressed fluid is discharged at the discharge port. In a scroll compressor, the compression medium comprises two scroll plates, which form the at least one compression chamber. One of these scroll plates is a stationary scroll plate, and the other is an orbital scroll plate, which moves in an orbital motion with respect to the stationary scroll plate. Both spiral plates typically comprise corresponding spiral casings that are interleaved when the spiral compressor components are assembled. The interleaved spiral casings and the base plates form at least one compression chamber. Due to the orbital motion of the spiral plate, the fluid is drawn into a pocket formed between the spiral casings. This pocket forms a compression chamber and is transported from the outermost locations of the interleaved spiral casings to the innermost locations of the interleaved spiral casings. During this process, the fluid is compressed because the size of the pocket, i.e., the size of the compression chamber, decreases. At the innermost location of the interleaved spiral casings, the compressed fluid is expelled from the compression chamber into a discharge chamber of the compressor, from where it is discharged from the compressor through the discharge port. The expert in the art will appreciate that during the operation of a scroll compressor, while one compression chamber, which is formed by a pocket between the interleaved scroll wraps and the base plates of the scroll plates, moves to the innermost location, one or more additional compression chambers may subsequently form after further relative movement of the scroll plates.

[0013] During fluid compression within the compression chambers, the fluid pressure and temperature increase. This increase in fluid temperature also raises the temperature of the spiral plates, which form the one or more compression chambers, due to contact between the spiral plates and the fluid. In addition, friction losses caused by the orbital spiral plate movement also increase the temperature of the spiral plates. However, only one side of each spiral plate is directly affected by the temperature increase within the at least one compression chamber, namely, the side of the spiral plate comprising the spiral envelope and facing the other respective spiral plate. For the purposes of this disclosure of the invention, this side is referred to as the front side of the spiral plate, while the side of each spiral plate opposite its front side is referred to as the back side of the spiral plate. Consequently, a substantial temperature difference can develop between the back side of the spiral plate and the front side comprising the spiral envelope.

[0015] [0006] In the art, different scroll compressor configurations are known, operating at different pressure and temperature ranges. For example, one configuration comprises a low-pressure side and a high-pressure side. The low-pressure side may include a suction port, a motor and crankshaft for operating the scroll compressor, and a lubricant supply, while the high-pressure side comprises the discharge port. According to this definition, the scroll assembly is neither part of the low-pressure side nor part of the high-pressure side, but forms a transition area between the two sides. Furthermore, the stationary scroll plate may make at least partial contact with the high-pressure side, and/or the orbital scroll plate may make at least partial contact with the low-pressure side. In this low-pressure and high-pressure side configuration, the fluid is received at a suction port on the low-pressure side, compressed in at least one compression chamber formed by the spiral plates, and then supplied to the high-pressure side. Those skilled in the art will appreciate that deviations from this definition of the low-pressure and high-pressure side configuration may be possible without departing from the scope of this application.

[0017] On the low-pressure side, the temperature of the fluid and surrounding components is quite low. For example, the temperature may be similar to the temperature of the fluid when it enters the suction port. The temperature of the fluid entering the suction port can be called the fluid intake temperature. However, it is also possible for the temperature on the low-pressure side to be higher than the temperature of the fluid entering the suction port, for example, due to engine operation and friction between the engine, crankshaft, and orbital spiral plate. Therefore, the fluid temperature on the low-pressure side can be called the suction-side temperature, because it refers to the temperature on the compressor side that includes the suction port. The suction-side temperature may be similar to the fluid intake temperature, or in the case of, for example, heat generation from engine operation and friction losses, the suction-side temperature may be higher than the fluid intake temperature. Those skilled in the art will understand that the suction-side temperature does not represent a single, specific temperature value, but rather a temperature range. This range may have the fluid intake temperature as its lower limit, while its upper limit depends on the compressor's operation and the heat generated by the engine and the friction caused by the crankshaft and scroll plates. Typically, the upper limit is less than or equal to the temperature at which the fluid will be discharged from the compressor at the discharge port.

[0019] Due to the temperature increase during the compression process, the temperature of the fluid and components on the high-pressure side is higher than the temperature on the low-pressure side, i.e., the suction-side temperature. Since this higher temperature refers to the temperature at which the compressed fluid will be discharged from the discharge port, this higher temperature can be called the discharge temperature.

[0021] Consequently, the fluid temperature in the at least one compression chamber lies within a range between the low temperature, referred to as the suction-side temperature, and the high temperature, referred to as the discharge temperature. The temperature within the at least one compression chamber is called the compression chamber temperature. Since the at least one compression chamber receives fluid from the low-pressure side at the suction-side temperature, and because the temperature increases during compression, the compression chamber temperature represents a range that can vary from the suction-side temperature to the discharge temperature. Therefore, in a scroll compressor with a low-pressure side and a high-pressure side configuration, there are distinct temperature zones. Exemplary temperature zones for such a scroll compressor configuration are described in more detail below with reference to Figure 2.

[0023] In a low-pressure side and high-pressure side configuration, the back side of the orbital spiral plate may make contact with the low-temperature area, which operates at the suction-side temperature, while the front side of the orbital spiral plate makes contact with the compression chambers and experiences the compression chamber temperature, which is higher than the suction-side temperature in at least some locations within the interleaved spiral plates. In this case, there is a temperature difference between the front and back sides, where the temperature difference is the difference between the suction-side temperature and the compression chamber temperature. As those skilled in the art will appreciate, the temperature distribution on the front side of the orbital spiral plate may be non-homogeneous, since the refrigerant compressed in the innermost locations of the spiral envelope has a higher temperature than the refrigerant in the outermost locations of the spiral envelope, which essentially has the temperature of the refrigerant received from the low-pressure side. Furthermore, the temperature distribution on the back side of the orbital spiral plate may be non-homogeneous, as some parts of the back side may be supported by a frame or thrust plate and may experience friction, which can also increase the temperature locally, while other parts may be affected by the lubricant. These effects can contribute to the temperature difference between the front and back sides of the orbital spiral plate.

[0025] The temperature difference is different on the stationary spiral plate. As those skilled in the art will appreciate, there are different ways in which the stationary spiral plate can be positioned within the scroll compressor. In some examples, the back side of the stationary spiral plate may make direct contact with the high-pressure side and may experience the discharge temperature, while in other examples, another component or part of the casing may provide a boundary between the stationary spiral plate and the high-pressure side, so that the temperature on the back side of the stationary spiral plate may be substantially lower than the discharge temperature. However, in most applications, the back side of the stationary spiral plate experiences a temperature that is higher than the suction-side temperature, for example, due to heat transfer from the high-pressure side.

[0027] [0012]Conversely, the front side of the stationary spiral plate experiences the compression chamber temperature, or in other words, the temperature of the fluid inside the compression chamber. As mentioned earlier, the compression chamber temperature represents a temperature range between the suction-side temperature and the discharge temperature. As those skilled in the art will appreciate, in the innermost section of the spiral wraps, from where the compressed fluid will be expelled into the discharge chamber, the compressed fluid has a temperature that may be similar to the discharge temperature, or in other words, to the high temperature experienced by the stationary spiral plate on its rear side. In the outer parts of the interleaved spiral wraps, i.e., the positions where fluid compression begins, the temperature may be similar to the suction-side temperature. This can result in a non-homogeneous temperature distribution on the front side. Therefore, in the stationary spiral plate, there is a substantial temperature difference between the discharge temperature on the back side and the compression chamber temperature on the front side, which increases from the suction side temperature at the outermost locations of the spiral wraps to the higher temperature of the compressed refrigerant at the innermost locations of the spiral wraps.

[0029] In another configuration, called the high-side configuration, both spiral plates are surrounded by the discharge fluid at a very high temperature. In this case, the stationary spiral plate, as well as the orbiting spiral plate, each experiences, at least locally, a temperature difference between the discharge temperature and the compression chamber temperature that is at least locally lower.

[0031] Other examples of spiral plates for spiral compressors are documents US 2020/217321 A1 and US 2010/254835 A1.

[0033] In any configuration, the temperature difference leads to differences in thermal expansion and, therefore, to induced stress and strain in the scroll plates. These effects can result in leaks or reduced efficiency of the scroll compressor.

[0035] Therefore, there is a need in the technique to reduce the thermal deformation of the spiral plates in a spiral compressor.

[0037] The aforementioned need is satisfied by a spiral plate according to the present invention.

[0039] The invention is defined by independent claim 1.

[0041] Preferred embodiments are set forth in the dependent claims. The spiral plate according to the present invention is for use in a spiral compressor. As the person skilled in the art will appreciate, the principles of the present invention can be applied to an orbital spiral plate or to a stationary spiral plate.

[0043] A spiral plate according to the present invention comprises a base plate. The base plate has a first side and a second side, wherein the second side is opposite the first side. The first side may be referred to as the front side of the spiral plate, while the second side may be referred to as the rear side of the spiral plate. A spiral wrap is formed on the first side of the base plate. The spiral wrap is interleaved with a corresponding spiral wrap of another spiral plate. Between the spiral wraps and the base plates of both spiral plates, compression chambers can be formed by the orbital motion of at least one of the spiral plates when the spiral wraps are interleaved and the compressor is operated.

[0045] According to the present invention, the base plate comprises one or more recesses. The one or more recesses may be located on the second side of the base plate. An insulating material is located in at least one of the one or more recesses. The insulating material reduces the thermal stress and deformation induced by the temperature difference between opposite sides of the spiral plate.

[0047] Depending on the location of the insulating material, the insulating material can, for example, reduce heat transfer between opposite sides of the spiral plate and/or isolate one side of the spiral plate from the surrounding temperature area. For example, in a preferred embodiment, at least one of the one or more recesses can be located on a surface of the second side of the base plate, thus isolating the base plate from its surrounding area. The insulating material located in the recess can protect the corresponding side of the spiral plate from its surrounding area and can therefore reduce the influence of the surrounding temperature on that side of the spiral plate. In such a case, the temperature of both sides of the spiral plate can be more similar, thus reducing the temperature difference. In the case of a low-pressure side and high-pressure side configuration, the surrounding area can refer, for example, to the low-pressure side of the scroll compressor when the scroll plate is an orbital scroll plate, or the surrounding area can refer to the high-pressure side of the scroll compressor when the scroll plate is a stationary scroll plate. Similarly, the surrounding area can be the high-pressure side if the scroll compressor has a high-side configuration.

[0048] In a preferred embodiment, at least one of the one or more recesses is located on a surface of the second side of the base plate. Placing a recess on the surface of the second side and placing the insulating material in said recess on the surface allows the base plate to be isolated from its surrounding area and thus protects the base plate from lower or higher temperatures and their effects on the temperature difference on the base plate.

[0050] In some preferred embodiments, the spiral plate may be configured as an orbital spiral plate. In an orbital spiral plate, the second side of the base plate may comprise a receptacle configured to receive a portion of a compressor crankshaft. When the crankshaft is operated, placing a portion of the crankshaft into a receptacle allows the crankshaft motion to be transferred to the orbital spiral plate. The receptacle may be in the form of a protrusion, preferably ring-shaped, so that a crankshaft pin can be placed in the ring-shaped protrusion. However, the receptacle may also be an opening in the base plate. In an orbital spiral plate, at least one of the one or more recesses may preferably be located within the receptacle. Typically, the crankshaft is lubricated by a lubricant that generally has a lower temperature than the temperature of the fluid inside the compression chambers; for example, the lubricant may have the temperature of the suction side. The crankshaft pin that engages with the orbital spiral plate bearing can also be lubricated to reduce wear between the pin and the bearing. Consequently, the bearing surface will experience the relatively low temperature of the lubricant, for example, the suction side temperature, while the opposite side of the base plate at the bearing location may experience a much higher temperature from the compressed fluid, potentially reaching the discharge temperature. Therefore, it is preferable to provide a recess with insulating material in the bearing, as this effectively reduces heat transfer.

[0052] In addition to or as an alternative to placing a recess and insulating material inside the crankshaft bearing, at least one of the one or more recesses may be located outside the bearing, meaning that the recess surrounds, at least partially, the bearing. The temperature difference on the sides of the base plate can therefore be reduced by isolating the back side of the orbital spiral plate from its surrounding area, for example, a thrust surface, which can be used to support the orbital spiral plate. Preferably, the at least one recess located outside the bearing may form a closed ring around the bearing, thus reducing the temperature difference evenly around the bearing. Furthermore, at least two recesses may form rings around the bearing. These rings may be concentric and can improve the management of the temperature difference over a larger portion of the orbital spiral plate, resulting in a more evenly reduced temperature difference.

[0054] In any of the preferred embodiments mentioned above, the insulating material may generally have low thermal conductivity. Consequently, non-metallic material may preferably be used as the insulating material. Examples of such materials may be synthetic polymers, preferably composed of polyamides, such as nylon, polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK), or ceramic materials.

[0056] The aforementioned need can also be satisfied by a scroll compressor comprising a first scroll plate as described in the preceding disclosure. Said scroll compressor further preferably comprises a second scroll plate, which also includes features for improving temperature differential and reducing heat-induced stress and strain. Said second scroll plate may include features similar to the first scroll plate or any of the embodiments mentioned above. However, if the second scroll plate is a stationary scroll plate, the second scroll plate may also include additional features for reducing thermal strain, as described below.

[0058] Said second spiral plate, which is a stationary spiral plate, comprises a second base plate. The second base plate has a front side and a rear side, wherein the rear side is opposite the front side. A second spiral envelope is formed on the front side of the second base plate. The spiral envelope is adapted to interact with a corresponding spiral envelope of the first spiral plate (i.e., orbital). Between the spiral envelopes and the base plates of both spiral plates, at least one compression chamber can be formed. The fluid in the compression chamber is compressed by the orbital motion of at least the orbital spiral plate with respect to the stationary spiral plate.

[0060] The second spiral plate further comprises an injection channel, which is formed within the second base plate. The injection channel provides an injection path for injecting fluid into the at least one compression chamber formed between the spiral wraps of the spiral plates. Those skilled in the art will be aware that the location of the at least one compression chamber formed between the spiral wraps may change during the orbital motion of the spiral plate. Therefore, it is sufficient that the injection path be configured to inject fluid into the at least one compression chamber at least at a particular instant during the operation of the compressor.

[0061] An opening may be located at the end of the injection channel, which can be used to connect the injection channel to an injection line of a refrigeration cycle. The injection channel can be used to inject fluid, for example, taken from a refrigeration cycle, into the at least one compression chamber formed between the corresponding spiral casings. The fluid can be injected at an intermediate pressure. In this respect, intermediate pressure refers to a pressure higher than the fluid pressure at the suction port, but lower than the fluid pressure at the discharge port. The temperature of the injected fluid can be lower than the discharge temperature. Preferably, the temperature of the injected fluid can be an intermediate temperature, i.e., a temperature higher than the temperature on the suction side, but lower than the discharge temperature. However, in other preferred embodiments, it may also be possible for the temperature of the injected fluid to be even lower than the temperature on the suction side.

[0063] Furthermore, the second spiral plate comprises a recess, referred to as the second recess to distinguish it from the one or more recesses of the first spiral plate, which comprise an insulating material, as mentioned above, and which are referred to as the first recesses for the purpose of this embodiment. The second recess is located on the second side of the second spiral plate. In addition, the second spiral plate comprises an insert. The insert is positioned within the second recess on the second side of the second base plate of the second spiral plate. The insert thus forms a cooling chamber within the second recess, or in other words, the insert separates a portion of the volume within the second recess of the second spiral plate. The second spiral plate further comprises an inlet channel and an outlet channel. The cooling chamber is connected to the injection channel via the inlet channel, and the cooling chamber is connected to the interior of the second spiral shell via the outlet channel. The cooling chamber is connected to the inlet channel via one or more first openings in the cooling chamber, and the connection to the outlet channel via one or more second openings in the cooling chamber. Consequently, the cooling chamber is configured to receive a portion of the fluid from the injection channel through the inlet channel. After the received fluid passes through the cooling chamber, the cooling chamber supplies the fluid to the at least one compression chamber formed between the interleaved spiral sleeves via the outlet channel.

[0065] As mentioned previously, the fluid in the injection channel may have an intermediate temperature, which is lower than the discharge temperature. Therefore, during operation, the cooling chamber will have a lower temperature than the back side of the stationary spiral plate. Consequently, the areas located very close to the cooling chamber will be cooled by the intermediate-temperature fluid. Preferably, the location of the second recess in the second spiral plate, and therefore the location of the cooling chamber, is selected so that large areas of the second spiral plate can be cooled. This reduces the stress and thermal strain induced by the temperature difference and heat transfer between the back and front sides of the second spiral plate.

[0067] In a preferred embodiment of the second spiral plate, the second recess located on the rear side of the second spiral plate may have an annular shape. More preferably, the center of the annular recess may be concentric with the center of the second base plate. As explained in more detail below, the second recess of the second spiral plate provides an intermediate pressure cavity, which can be used to push the stationary spiral plate toward the orbital spiral plate and improve the fit between the interleaved spiral wraps. In the case of a second annular recess, the second spiral plate is pushed uniformly toward the first spiral plate. In the case of a second annular recess, the insert positioned within the second recess may form the cooling chamber in at least a portion of the second annular recess. Preferably, the insert may also have an annular shape and may form the cooling chamber over the entire annular recess. In this type of configuration, the injected fluid can flow through the entire annular chamber and cool a wide area of the second base plate.

[0069] Furthermore, the remaining volume of the second recess of the second spiral plate, i.e., the volume not forming the cooling chamber, can be used to provide an intermediate pressure cavity. When assembled in a scroll compressor, such an intermediate pressure cavity can be formed between the remainder of the second recess of the second scroll plate and a part of the compressor housing, for example, a plate to which the second scroll plate is attached. The intermediate pressure cavity can be connected to the at least one compression chamber formed between the spiral wraps of the scroll plates by means of a so-called bleed hole. This generates pressure within the intermediate pressure cavity located on the back side of the second scroll plate, which presses the second scroll plate against the first scroll plate and improves the fit between the scroll plates. In addition, the intermediate pressure cavity and the bleed hole improve the pressure balance of the compression chambers. Alternatively, the intermediate pressure cavity can be connected, by means of a passage, to at least one compression chamber.

[0071] [0035] In some preferred embodiments of the second spiral plate, the cooling chamber, inlet channel, and outlet channel can define a cooling path configured to guide the fluid received from the injection channel into the interior of the second spiral shell. This can be achieved by providing the first and second openings of the cooling chamber, which are used to connect the cooling chamber to the inlet and outlet channels, at opposite ends of the chamber. Furthermore, the insert can form the cooling chamber such that the chamber provides a cooling path arranged in a predetermined manner through the base plate. For example, in the case of an annular configuration of the insert and cooling chamber, the first and second openings connecting the cooling chamber to the inlet and outlet channels can be provided on opposite sides of the annular chamber. Those skilled in the art will appreciate that in some embodiments of the second spiral plate, the fluid may flow from the injection channel through the inlet channel to the cooling chamber and then through the outlet channel directly into the spiral shell, whereas in other embodiments, the fluid may flow from the cooling chamber through the outlet channel back to the injection channel and then into the spiral shell. In the latter embodiment, the inlet channel may be connected to the injection channel at a first location and the outlet channel may be connected to the injection channel at a second location, wherein the first and second locations are different from each other and the first location is situated upstream of the second location (i.e., closer to the injection line of the coolant cycle from which the fluid is received).

[0073] In some preferred embodiments of the second spiral plate, the second recess of the second spiral plate may comprise a bottom portion and two side walls, and a sealed contact may be established between the insert and both side walls. The sealed contact separates the cooling chamber from the intermediate pressure cavity. Furthermore, the insert may comprise at least one protruding element, which makes contact with the bottom portion of the second recess of the second spiral plate. The at least one protruding element may define a height of the cooling chamber. By changing the dimensions of the at least one protruding element, the volume within the cooling chamber may be adjusted. Additionally or alternatively, the insert may comprise limbs, which establish the sealed connection with the side walls. For example, the insert may have an essentially U-shaped cross-section. This means that the insert has two limbs, i.e., the upward-facing limbs of the U, which are connected to the walls of the second recess of the second spiral plate. Opposite the upward-facing ends, the U-shaped insert may include at least one projecting element to define the height of the cooling chamber. Alternatively, the U-shaped insert may be inverted so that the upward-facing ends of the U face the underside of the second recess in the second spiral plate. In this way, the ends can define the height of the cooling chamber.

[0075] In some preferred embodiments of the second spiral plate, the insert may be made of the same material as the second spiral plate or a material having a thermal expansion characteristic similar to that of the second spiral plate. For example, suitable materials may be steel or cast iron. However, non-metallic materials may also be possible if their thermal expansion characteristic is similar to that of the second spiral plate. Furthermore, in some embodiments, it may be possible to place a seal between the insert and the walls of the second recess of the second spiral plate.

[0077] In some preferred embodiments, an insulating layer may be added to the insert. The insulating layer can improve the thermal insulation between the cooling chamber and the intermediate pressure cavity. The insulating material generally has low thermal conductivity. Consequently, a non-metallic material may preferably be used as the insulating material. Examples of such materials may be synthetic polymers, preferably composed of polyamides, such as nylon, polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK), or ceramic materials. Alternatively, the insert may be coated with an insulating material. Preferably, the insulating layer is added to the insert on the side facing the intermediate pressure cavity. This would prevent heat transfer from the intermediate pressure cavity to the cooling chamber.

[0079] The following description and accompanying drawings set forth in detail certain illustrative aspects of the apparatus and procedure described above. However, these aspects only indicate some of the various ways in which the principles of different embodiments may be employed, and it is intended that the described embodiments include all of these aspects and their equivalents. In particular, it should be noted that, although the following drawings show only examples of embodiments of scroll compressors, the invention may be applied to any type of compressor.

[0081] In the drawings, similar reference characters generally refer to the same parts throughout the different drawings. The drawings are not necessarily to scale, the emphasis being generally on illustrating the principles of the invention.

[0083] In the following description, various embodiments of the invention are described with reference to the following drawings, in which:

[0084] FIG. 1 shows a cross-sectional view of an embodiment of a scroll compressor with an orbital scroll plate according to the present invention, wherein the scroll compressor has a low pressure and high pressure configuration.

[0086] FIG. 2 shows a highlighted portion of the top of the scroll compressor of figure 1 and illustrates the temperature areas within the scroll compressor.

[0088] FIGS. 3a - 3d show cross-sectional views of some examples of a spiral plate, wherein figure 3c shows an embodiment of the spiral plate according to the present invention.

[0090] FIGS. 4a - 4c show examples of embodiments of orbital spiral plates according to the present invention, wherein (a) is a perspective view of an example embodiment of an orbital spiral plate cut in half and (b), (c) are top views of the back side of orbital spiral plates with different insulating material designs.

[0092] FIGS. 5a, 5b show an example of an orbital spiral plate for illustrative purposes only, wherein the base plate consists of two separate parts

[0094] FIGS. 6a - 6c wherein the first part comprises the first side and the second part comprises the second side, and wherein the insulating material is placed between the first and second parts. (a) is a perspective view of said embodiment of an orbital spiral plate cut in half, and (b) is an orderly exploded view of the orbital spiral plate according to said embodiment. They show further examples of a spiral compressor in which the present invention may be used, wherein the spiral compressor has a so-called high-side compressor configuration. (a) shows a cross-sectional view of a spiral compressor with thermal strain management features added to the orbital spiral plate, (b) shows a highlighted portion of the top of the spiral compressor of (a) and illustrates the temperature areas within the spiral compressor, and (c) shows a cross-sectional view of a spiral compressor with thermal strain management features added to the stationary spiral plate.

[0096] FIG. 7 shows a cross-sectional view of an example of a stationary spiral plate that can be used in addition to the orbital spiral plate according to the present invention.

[0098] FIGS. 8a, 8b show (a) a cross-sectional detail view of an example of an insert placed within a second recess of the stationary spiral plate illustrated in figure 7 and (b) different views.

[0100] FIGS. 9a, 9b show two example types of cooling chambers formed within the second recess of the stationary spiral plate of figure 7 by the insert illustrated in figure 8.

[0102] The following detailed description refers to the accompanying drawings, which show, by way of illustration, specific details and modes of embodiment in which the invention can be put into practice.

[0104] The word "exemplary" is used herein in the sense of "serving as an example, case, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferable or advantageous over other embodiments or designs.

[0106] Figure 1 shows a cross-sectional view of an embodiment of a scroll compressor with an orbital scroll plate according to the present invention. Figure 100 shows a scroll compressor. The scroll compressor comprises a housing 110, a suction port 140, a discharge port 150, a stationary scroll plate 120, and an orbital scroll plate 130. Furthermore, the scroll compressor 100 comprises a motor 160, which is connected to a crankshaft 170, and the crankshaft 170 is connected to the orbital scroll plate 130. Therefore, the motor drives the crankshaft 170, causing it to rotate. Because the crankshaft is connected to the orbital scroll plate 130, the rotary motion is transferred to an orbital motion of the orbital scroll plate 130. Additionally, the scroll compressor 100 comprises a lubricant supply 180, which can provide lubricant to the crankshaft 170, the orbital scroll plate 130, and the stationary scroll plate 120.

[0108] The scroll compressor 100 has a low-pressure side and a high-pressure side configuration. In this configuration, the low-pressure side comprises a lubricant supply 180, the motor 160, the crankshaft 170, and the suction port 140, while the high-pressure side comprises the discharge port 150. The stationary scroll plate 120 and the orbital scroll plate 130 form a transition area from the low-pressure side to the high-pressure side.

[0109] Figure 2 shows a highlighted area of the top of the scroll compressor in Figure 1 and illustrates the temperature areas within the scroll compressor.

[0111] On the low-pressure side, the fluid is received at the suction port. Since the fluid received at the suction port has a fairly low pressure and temperature, the temperature on the low-pressure side is also quite low. In Figure 2, the temperature on the low-pressure side is denoted as the suction-side temperature T<s>. Although the low-pressure side is characterized by a single temperature T<s> in Figure 2, those skilled in the art will appreciate that the temperature distribution on the low-pressure side is not necessarily homogeneous.

[0113] Similarly, on the high-pressure side, the compressed fluid has the highest temperature, which is indicated as the discharge temperature T<d>. Again, those skilled in the art will appreciate that deviations from the discharge temperature may occur and that the temperature distribution on the high-pressure side is not necessarily homogeneous.

[0115] Furthermore, the temperature in the compression chambers formed between the orbital spiral plate and the stationary plate is greater than or equal to the suction-side temperature T<s> and less than or equal to the discharge temperature T<d>. During the compression process, the temperature in the compression chamber increases from the suction-side temperature T<s> to the discharge temperature T<d>. The temperature in the compression chambers is denoted as T<c>. Again, the person skilled in the art will appreciate that the temperature distribution in the compression chambers is not homogeneous, as previously described.

[0117] The compressor configuration shown in Figure 2 also has a so-called intermediate pressure cavity, which is located between the stationary spiral plate and a portion of the support frame to which the stationary spiral plate is attached. The intermediate pressure cavity is connected to the compression chambers for at least part of the time by means of a so-called bleed hole, which relates the pressure inside the compression chambers to the pressure inside the intermediate pressure cavity. Furthermore, the intermediate pressure cavity is used to press the stationary spiral plate against the orbital spiral plate, thereby improving the seal between the spiral plates. As shown in Figure 2, the fluid temperature inside the indicated intermediate pressure cavity is T<i>, which is higher than the suction-side temperature T<s> but lower than the discharge temperature T<d>.

[0119] As those skilled in the art will appreciate, the temperature areas depicted in Figure 2 are simplifications and are used for illustrative purposes only. As mentioned earlier, the temperature areas do not have to be homogeneous. Instead, they can represent temperature ranges. This is particularly important for the compression chamber temperature T<c>, which varies from values similar to the suction-side temperature T<s> at locations on the left and right sides of Figure 2 to values similar to the discharge temperature T<d> at the center of the interleaved spiral plates.

[0121] The front side of the stationary spiral plate faces the compression chambers and has a temperature similar to T<c>. The rear side of the stationary spiral plate makes contact with the intermediate pressure cavity, which has a temperature T<i>, and is in close contact with the high pressure side, which has a temperature T<d>. Therefore, the temperature on the rear side of the stationary spiral plate is higher than the temperature T<c> on the front side and may be close to the discharge temperature T<d>.

[0123] Similarly, the front side of the orbital spiral plate faces the compression chambers and also has a temperature similar to T<c>. The rear side of the orbital spiral plate makes contact with the low-pressure side, which has the temperature of the suction side, T<s>. Therefore, the temperature on the rear side of the orbital spiral plate is similar to the suction side temperature, T<s>.

[0125] Figures 3a to 3d show cross-sectional views of some examples of a spiral plate, wherein Figure 3c shows an embodiment of the spiral plate according to the present invention. In the first example of a spiral plate 130a shown in Figure 3a, the spiral plate 130a comprises a base plate 200 having a first side 205 and a second side 210. The first side comprises a spiral wrap 270 and may also be called the front side. The second side comprises a recess 220 located on the surface of the second side, which has an annular shape, such that it occurs on the left and right sides of the surface image. This recess 220 may be called the first recess, as described above. A more detailed example of an annular recess will be described below with reference to Figures 4a to 4c. An insulating material (not shown) can be placed inside the recess, as will be shown in more detail below with reference to Figures 4a to 4c.

[0127] The spiral plate 130a depicted in Figure 3a can be either a stationary spiral plate or an orbital spiral plate. However, spiral plate 130a is illustrated as an orbital spiral, which can be identified by the annular protrusion 240, forming a crankshaft bearing, as will also be described in more detail below with reference to Figures 4a to 4c.

[0128] Figure 3b illustrates a variation 130b of the spiral plate example 130a shown in Figure 3a. Here, a portion of the recess 220a extends into a portion of the annular protrusion 240, thereby permitting the placement of insulating material not only on the second side of the base plate 200, but also around the annular protrusion 240. This can limit thermal deformation of the annular protrusion 240.

[0130] In addition to the features of the spiral plate 130a or 130b depicted in Figures 3a, 3b, the spiral plate 130c depicted in Figure 3c comprises an additional recess 220b, which is situated in the recess formed by the annularly shaped protrusion 240. The person skilled in the art will appreciate that the recess 220b may be used in addition to the recess 220 as depicted in Figure 3c or, alternatively, to the recess 220 even if this is not explicitly shown in a separate drawing.

[0132] Whereas the recesses 220, 220b shown in Figures 3a to 3c are located on the surface of the second side 210 of the base plate 200, the spiral plate 130d shown in Figure 3d comprises recesses 225, 225b, which are located below the surface of the second side 210. Although the recesses 225, 225b in Figure 3d are shown in lateral positions (with respect to the surface of the second side) corresponding to the recesses 220, 220b of the example shown in Figure 3c, those skilled in the art will appreciate that other configurations are also possible. For example, a single recess may extend in a plane parallel to the surface of the base plate 200, may be annular, and may have a diameter extending to the extent of the base plate.

[0134] In the orbital spiral plate examples shown in Figures 3a to 3d, the recesses and insulating material are positioned near the protrusion to receive a portion of the crankshaft. Although other locations for the recess are possible and within the scope of this application, the exemplary locations shown in the drawings represent preferred examples. In the case of a low-pressure-side and high-pressure-side spiral compressor configuration, these preferred examples take into account the temperature differences between the first side, which experiences a temperature similar to the discharge temperature at the center of the spiral shell 270, and the second side, which experiences the substantially lower side temperature at the annular protrusion 240 caused by crankshaft lubrication with a lubricant and, additionally, contact with the vapor on the suction side received from the suction port.

[0136] Figures 4a to 4c show examples of embodiments of orbital spiral plates according to the present invention, wherein (a) is a perspective view of an embodiment of an orbital spiral plate cut in half, and (b) and (c) are top views of the rear side of two orbital spiral plates having different insulating material configurations. The embodiments shown in Figures 4a to 4c correspond to the illustration shown in Figure 3c. In these Figures 4a to 4c, the insulating materials 230 and 260 are shown located in the recesses 220 and 220b, respectively. Furthermore, due to the perspective view, the annular configuration of the recess 220 and the circular configuration of the recess 220b, as well as the annular configuration of the protrusion 240, can be identified more clearly compared to the cross-sectional views shown in Figure 3c.

[0138] In Figures 4a and 4b, insulating materials 230, 230a are represented by a ring made of insulating material located in an annular recess 220, while insulating material 260 is represented by a circle or disk made of insulating material located in a circular recess 220b. Unlike insulating material 230a in Figure 4b, insulating material 230b in Figure 4c does not form a closed ring. This allows the insulating material to increase or decrease in size due to thermal effects within the material. As the person skilled in the art will appreciate, this benefit can also be achieved by providing multiple portions of insulating material, which are placed in sections of the annular recess.

[0140] Figures 5a, 5b show an example of an orbital spiral plate 130b for illustrative purposes only, wherein the base plate consists of two parts, wherein the first part comprises the first side and the second part comprises the second side and wherein the insulating material is placed between the first part and the second part.

[0142] In this example, the base plate of the spiral plate 130b is formed by a first part 310, a second part 320, and an insulating layer 330 placed in a recess between the first part 310 and the second part 320. Thus, a recess within the meaning of the present invention can also be interpreted as the separation of the base plate into two parts 310 and 320. This example isolates the first part 310 from the second part 320 by means of the insulating layer 330, which reduces heat transfer between the two parts of the base plate of the spiral plate.

[0144] [0064] Figures 6a to 6c show further examples of a scroll compressor in which the present invention may be used, wherein the scroll compressor has a so-called high-side compressor configuration. (a) shows a cross-sectional view of the scroll compressor with thermal strain management features added to the orbital scroll plate, (b) shows a highlighted portion of the top of the scroll compressor of (a) and illustrates the temperature areas within the scroll compressor, and (c) shows a cross-sectional view of the scroll compressor with thermal strain management features added to the stationary scroll plate. Similar to the scroll compressor 100 depicted in Figure 1, the scroll compressor 400a depicted in Figure 6a comprises a housing 410, a motor 460, a crankshaft 470, and a lubricant supply 480. All these components may have characteristics similar to the corresponding characteristics of the scroll compressor 100.

[0146] Furthermore, the scroll compressor 400a comprises a scroll assembly, which forms one or more compression chambers during operation of the scroll compressor 400a. The scroll assembly consists of a stationary scroll plate 420 and an orbital scroll plate 430. Both scroll plates 420, 430 comprise scroll wraps, which form one or more compression chambers between them. Unlike the scroll plates 120, 130 of the scroll compressor 100, the scroll plates 420, 430 of the scroll compressor 400a are located on the high-pressure side. The scroll compressor 400a comprises a suction port 440 for receiving fluid and a discharge port (not shown) for discharging fluid from the compressor. Unlike the scroll compressor 100, the suction port 440 does not direct the received fluid to a low-pressure side, but feeds the fluid directly to the one or more compression chambers formed between the orbital scroll plate 430 and the stationary scroll plate 420. The discharge port of the scroll compressor 400a may be similar to the discharge port 150 of the scroll compressor 100.

[0148] Since both spiral plates 420, 430 are located on the high-pressure side, the back sides of both spiral plates 420, 430 experience a temperature higher than the discharge temperature T<c>. As illustrated in Figure 6b, the stationary spiral plate 420 is surrounded by fluid discharged from the one or more compression chambers in the center of the stationary spiral plate 420, so that the stationary spiral plate is surrounded by fluid having the discharge temperature T<d>. Within the spiral envelopes of the spiral plates 420, 430, the spiral plate experiences different temperatures. The one or more compression chambers receive the fluid directly from the suction port, thus experiencing, at least partially, the suction port temperature T<sp>. Since the fluid is compressed and therefore its temperature increases, the spiral plates at the locations of the interleaved spiral wraps experience the compression chamber temperature T<c>, which increases from T<sp> to T<d>.

[0150] In the example shown in Figure 6a, the orbital spiral plate 430 comprises an insulating layer 510 located on its back side. This insulating layer 510 improves the thermal deformation behavior of the orbital spiral plate in a manner similar to that described with respect to the insulating material placed in recesses for the spiral plates of the high-pressure-side and low-pressure-side spiral compressor embodiments.

[0152] The scroll compressor 400b depicted in Figure 6c is also a high-side scroll compressor and has similar characteristics to the scroll compressor 400a depicted in Figure 6a. Furthermore, its temperature ranges are similar to those depicted in Figure 6b. However, unlike the scroll compressor 400a depicted in Figure 6a, the scroll compressor 400b depicted in Figure 6c incorporates thermal strain management features applied to the stationary scroll plate. For example, the stationary scroll plate 420 may include a recess with insulating material on the side opposite the side with the scroll wrap.

[0154] Alternatively, as illustrated in Figure 6c, an insulating layer 520 can cover the stationary spiral plate 420 and protect it from the high temperature T<d>. The insulating layer 520 can be made of the same material as the insulating material discussed above.

[0156] The following description refers to the case where the spiral plate having one or more recesses with insulating material is an orbital spiral plate. The one or more recesses of the orbital spiral plate in which the insulating material is placed as described above may be referred to as one or more first recesses. In this example, heat strain management may be further improved by adding heat strain management features to the stationary spiral plate. Preferably, the heat strain management features added to the stationary spiral plate may comprise an insert, which is placed in a second recess of the stationary spiral plate so that a cooling chamber is formed between the insert and the stationary spiral plate, said second recess being connected to a fluid injection line. Figures 7 to 9 illustrate said stationary spiral plate and a corresponding insert for forming a cooling chamber.

[0158] Figure 7 shows a cross-sectional view of an example of a stationary spiral plate 120a. Compared to the stationary spiral plate 120 of the compressor 100, the stationary spiral plate 120a depicted in Figure 7 comprises an insert 650 positioned within a second recess 630 on a second side 610 of a base plate 600 of the stationary spiral plate 120a. The insert 650 forms a cooling chamber 640 within the second recess 630, representing a volume within the second recess 630 that is separate from the remaining volume.

[0159] In order to provide a sealed separation of the remaining volume within the second recess 630, the side portions of the insert 650 are connected to the side walls 630a, 630b of the second recess 630. The side portions may be formed by limbs 655a, 655b as will be illustrated in more detail with reference to Figure 8a.

[0161] Another part of the insert 650, which may consist of one or more protrusions 660, maintains the insert 650 at a particular distance from the lower portion 630c of the second recess 630. As illustrated in Figure 7, the protrusion 660 may define the height of the cooling chamber 640. In the example shown in Figure 7, the second recess 630 and the insert 650 have annular conformations.

[0163] The fluid received, for example, from an injection line of a refrigeration cycle flows through the injection channel 680 within the base plate 600. Through an inlet channel 645a, a portion of the fluid flows into the cooling chamber 640. After passing through the cooling chamber 640, the fluid flows through the outlet channel 645b into the compression chamber formed between the interleaved spiral wraps 670. A person skilled in the art will be aware that the inlet channel 645a can be formed in various ways. An example of such an inlet channel is shown in Figure 7, while Figure 8a shows a slightly different configuration.

[0165] Figures 8a, 8b show (a) a cross-sectional detail view of a preferred example of an insert placed within a second recess of a stationary spiral plate and (b) a perspective view of the preferred example of the insert.

[0167] The insert 650 shown in Figure 8a essentially has a U-shaped cross-section with two ends 655a and 655b. These ends 655a, 655b can be used to connect the insert 650 to the side walls 630a, 630b of the second recess 630. The connection can preferably be a sealed connection, so that the cooling chamber 640 is sealed from the intermediate pressure cavity formed in the remaining portion of the second recess 630. The sealing can be achieved, for example, by interference fit or the use of a sealing element.

[0169] Furthermore, the insert 650 comprises at least one protrusion 660. The at least one protrusion 660 is located on the lower portion 630c of the second recess. Therefore, the length of the protrusion 660 defines the height of the cooling chamber 640. In the example shown in Figure 8a, the insert 650 comprises two protrusions 660, which are located on the edges of the insert 650, or in other words, at locations opposite the extremities 655a, 655b. The two protrusions 660 allow for the formation of the cooling chamber 640 between them and the lower portion of the second recess. Alternatively, although not shown, the insert may comprise a single protrusion located in the center (similar to that shown in Figure 7), so that the cooling chamber is formed on both sides of the protrusion.

[0171] In another example, not shown in the figures, the extremities 655a, 655b of the insert 650 can be oriented towards the lower part 630c of the second rebate 630. In this case, no protrusion is necessary since the height of the chamber 640 is defined by the length of the extremities 655a, 655b.

[0173] Furthermore, as already shown in Figures 7 and 8a, the connection between the insert 650 and the wall of the second recess can be sealed by means of one or more seals 665. These seals can be sealing elements (e.g., O-rings) or can be established by means of an interference fit.

[0175] Figure 8b shows three views of the insert 650 of Figure 8a without the surrounding stationary spiral plate. The first image is a perspective view of the insert 650, while the second image is a perspective view of a cross-section of the insert 650, and the third image is a cross-sectional view of the insert 650. The insert 650 comprises a first and a second end 655a, 655b for connecting to the side walls of a second recess in a stationary spiral plate, and two protrusions 660 used to define the height of the cooling chamber. As can be seen in Figure 8b, the insert has an annular shape and is configured to fit into an annular recess in a stationary spiral plate.

[0177] Figures 9a and 9b show two exemplary types of cooling chambers formed within the second recess by the insert. Figures 9a and 9b illustrate a top view of the arrangement of cooling chamber 640 formed by the insert 650 in the second recess 630.

[0179] [0082] In the first example, shown in Figure 9a, the second recess 630 has an annular shape and extends around the opening 620. The cooling chamber 640a formed by the insert 650 within the second recess also has an annular shape. The openings from the cooling chamber 640a to the inlet and outlet channels, respectively, are not shown in the figure, but they can preferably be located on opposite sides of the annular ring, for example, at the 12 o'clock and 18 o'clock positions in Figure 9, or any other opposite location. In this way, the fluid received from the injection channel 680 by means of the first opening can be distributed in two ways within the cooling chamber 640a and directed to the second opening.

[0180] In the second example, shown in Figure 9b, the second recess 630 again has an annular shape and extends around the opening 620. The cooling chamber 640b formed by the insert 650 within the second recess comprises a passage, which is essentially formed by two concentric rings that are connected. In this way, the fluid can enter the cooling chamber 640b by means of the inlet channel that terminates in a first opening 710 and is guided through the cooling chamber 640b for almost the entire length of an outer ring of the second recess 630, makes a turn, and is then guided within the inner ring to the second opening 720 from where it is supplied to the outlet channel.

[0181] A person skilled in the art will appreciate that various other cooling chamber arrangements are also possible that achieve the same or similar effects to the examples explicitly shown in the figures. In particular, any arrangement in which the cooling chamber only covers a portion of the annular recess 230 will also be within the scope of the present invention as defined in the appended claims, even though such examples are not explicitly shown.

[0182] Furthermore, those skilled in the art will appreciate that multiple first openings, connecting the cooling chamber to the inlet channel within the motherboard, and multiple second openings, connecting the cooling chamber to the outlet channel, are also possible, although this is not explicitly shown. This allows for the design of curved cooling chambers and various branching configurations.

[0183] At least one protrusion of the insert can be used to define the course of the cooling chamber in order to achieve the designs mentioned above.

[0184] The foregoing includes examples of one or more embodiments. Of course, it is not possible to describe all conceivable combinations of components or methodologies for the purpose of describing the aforementioned embodiments, but a person skilled in the art may recognize that many other combinations and permutations of various embodiments are possible. Accordingly, the embodiments described are intended to encompass all such alterations, modifications, and variations that fall within the scope of the appended claims.

Claims (5)

1. CLAIMS 1. A spiral plate for use in a spiral compressor (100), the spiral plate comprising: a base plate (200) having a first side (205) and a second side (210), wherein the second side (210) is opposite the first side (205); and a spiral wrap (270) formed on the first side (205) of the base plate (200); wherein the base plate (200) comprises one or more recesses (220, 220b) and wherein an insulating material (230, 260, 230a, 230b) is located in each of the one or more recesses (220, 220b); wherein the second side (210) of the base plate (200) further comprises a receptacle configured to receive a portion of a compressor crankshaft (100); and wherein at least one recess (220b) of the one or more recesses (220, 220b) is located within the recess on a surface of the second side (210) of the base plate (200); characterized by At least one additional recess (220) of the one or more recesses (220, 220b) is located outside the receptacle on the surface of the second side (210) of the base plate (200) and forms a closed ring around the receptacle. 2. The spiral plate according to claim 1, wherein the insulating material (230, 260, 230a, 230b) is a non-metallic material having low thermal conductivity. 3. A spiral compressor (100), comprising a spiral plate (130) according to any of the above-mentioned claims. 4. The spiral compressor (100) according to claim 3, wherein the spiral plate is an orbital spiral plate (130) and wherein the one or more recesses (220, 220a, 220b, 225, 225b) of the base plate (200) of the orbital spiral plate (130) are referred to as one or more first recesses (220, 220a, 220b, 225, 225b), the spiral compressor further comprising a second spiral plate (120a, 120b), wherein the second spiral plate (120, 120b) comprises: a second base plate (600) having a front side (605) and a back side (610), wherein the back side (610) is opposite the front side (605); a second spiral wrap (670) formed on the front side (605) of the second base plate (600), wherein the second spiral wrap (670) is adapted to interact with the spiral wrap (270) of the orbital spiral plate (130) to form at least one compression chamber; an injection channel (680) formed within the second base plate (600), the injection channel (680) providing an injection route for injecting fluid into the at least one compression chamber; a second recess (630) located on the rear side (610) of the second base plate (600); an insert (650) placed within the second recess (630), wherein the insert (650) forms a cooling chamber (640, 640a, 640b) within the second recess (630), an inlet channel (645a) through which the cooling chamber (640, 640a, 640b) is connected to the injection channel (680); and an outlet channel (645b) through which the cooling chamber (640, 640a, 640b) is connected to the inside of the second spiral envelope (670). 5. The spiral compressor (100) according to claim 4, wherein the cooling chamber (640, 640a, 640b), the inlet channel and the outlet channel define a cooling path configured to guide fluid from the injection channel (680) into the interior of the spiral casing (670).