Compressor with level sensor

Abstract

A compressor includes a housing defining a sump for collecting lubricant. A pump is positioned within the housing for circulating the lubricant. The pump includes a lubricant intake tube defining a pump inlet positioned within the sump. The compressor also includes a measurement device. A controller of the compressor may be configured for, and / or a method of operating the compressor may include, operating the compressor to increase the pressure and temperature of a refrigerant and detecting, with the measurement device, a position of the compressor while operating the compressor. In response to the detected position of the compressor, the compressor may be deactivated.

Description

FIELD OF THE INVENTION

[0001] The present subject matter relates generally to compressors and sensors for compressors.BACKGROUND OF THE INVENTION

[0002] Certain appliances, e.g., refrigerators include sealed systems for heating and / or cooling a fluid, such as generating a flow of cooled air for chilled chambers of the refrigerator appliance, heating or cooling air with an air conditioner appliance, and / or heating air in a clothes dryer appliance. The sealed systems generally include a compressor that generates compressed refrigerant during operation of the sealed system. The compressed refrigerant flows to an evaporator where heat exchange between the refrigerant and another fluid, e.g., air, which may be useful for, e.g., in the refrigerator appliance example, cooling the chilled chambers and food items located therein.

[0003] An oil supply system is typically included within the compressor housing for lubricating moving parts thereof, such as a piston in a linear compressor or a rotor in a rotary compressor, to reduce friction losses (e.g., between the piston and a chamber wall in a linear compressor or between rotor vanes in a rotary compressor) which can negatively affect an efficiency of an associated sealed system and appliance, e.g., refrigerator appliance.

[0004] The oil supply system typically includes a reservoir or sump in which a volume of oil is retained and from which the oil is drawn by a pump for circulation within the compressor, e.g., between moving parts as mentioned. In some cases, however, an inlet of the pump may not be fully submerged within the volume of oil in the sump. For example, when the compressor is tipped or out of level, the volume of oil in the sump may flow away from the inlet of the pump. Thus, the pump may not be able to supply oil to fully lubricate the moving parts, or other issues such as cavitation of air bubbles within the pump may arise.

[0005] Accordingly, systems and methods for detecting such conditions in a compressor would be useful.BRIEF DESCRIPTION OF THE INVENTION

[0006] Aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

[0007] In an example embodiment, a compressor is provided. The compressor includes a housing defining a sump for collecting lubricant and a pump for circulating the lubricant within the housing. The pump includes a lubricant intake tube defining a pump inlet positioned within the sump. The compressor also includes a measurement device and a controller in operative communication with the measurement device. the controller is configured for operating the compressor to increase the pressure and temperature of a refrigerant and detecting, with the measurement device, a position of the compressor while operating the compressor. The controller is also configured for deactivating the compressor in response to the detected position of the compressor.

[0008] In another example embodiment, a method of operating a compressor is provided. The compressor includes a housing defining a sump for collecting lubricant and a pump for circulating the lubricant within the housing. The pump includes a lubricant intake tube defining a pump inlet positioned within the sump. The compressor also includes a measurement device. The method includes operating the compressor to increase the pressure and temperature of a refrigerant and detecting, with the measurement device, a position of the compressor while operating the compressor. The method further includes deactivating the compressor in response to the detected position of the compressor.

[0009] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

[0011] FIG. 1 is a front elevation view of a refrigerator appliance according to an example embodiment of the present subject matter.

[0012] FIG. 2 is schematic view of certain components of the example refrigerator appliance of FIG. 1.

[0013] FIG. 3 is a perspective, section view of an exemplary compressor according to one or more exemplary embodiments of the present subject matter.

[0014] FIG. 4 is another perspective, section view of the exemplary compressor of FIG. 3 according to one or more exemplary embodiments of the present subject matter.

[0015] FIG. 5 is a perspective view of a compressor with a compressor housing removed for clarity according to one or more exemplary embodiments of the present subject matter.

[0016] FIG. 6 is a section view of the exemplary compressor of FIG. 3 with a piston in an extended position according to an exemplary embodiment of the present subject matter.

[0017] FIG. 7 is a section view of the exemplary compressor of FIG. 3 with the piston in a retracted position according to an exemplary embodiment of the present subject matter.

[0018] FIG. 8 provides a schematic, cross sectional view of the exemplary compressor of FIG. 3 according to an exemplary embodiment of the present subject matter.

[0019] FIG. 9 provides a schematic perspective view of an exemplary compressor including a measurement device, according to one or more embodiments of the present subject matter.

[0020] FIG. 10 provides a flow chart diagram of an exemplary method of operation a compressor according to one or more embodiments of the present subject matter.

[0021] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.DETAILED DESCRIPTION

[0022] Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0023] As used herein, terms of approximation, such as “generally,” or “about” include values within ten percent greater or less than the stated value. When used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction. For example, “generally vertical” includes directions within ten degrees of vertical in any direction, e.g., clockwise or counter-clockwise.

[0024] FIG. 1 depicts a refrigerator appliance 10 that incorporates a sealed refrigeration system 60 (FIG. 2). It should be appreciated that the term “refrigerator appliance” is used in a generic sense herein to encompass any manner of refrigeration appliance, such as a freezer, refrigerator / freezer combination, and any style or model of conventional refrigerator. In addition, it should be understood that the present subject matter is not limited to use in appliances. Thus, the present subject matter may be used for any other suitable purpose, such as vapor compression within air conditioning units or air compression within air compressors.

[0025] In the illustrated example embodiment shown in FIG. 1, the refrigerator appliance 10 is depicted as an upright refrigerator having a cabinet or casing 12 that defines a number of internal chilled storage compartments. In particular, refrigerator appliance 10 includes upper fresh-food compartments 14 having doors 16 and lower freezer compartment 18 having upper drawer 20 and lower drawer 22. The drawers 20 and 22 are “pull-out” drawers in that they can be manually moved into and out of the freezer compartment 18 on suitable slide mechanisms.

[0026] FIG. 2 is a schematic view of certain components of refrigerator appliance 10, including a sealed refrigeration system 60 of refrigerator appliance 10. A machinery compartment 62 contains components for executing a known vapor compression cycle for cooling air. The components include a compressor 64, a condenser 66, an expansion device 68, and an evaporator 70 connected in series and charged with a refrigerant. As will be understood by those skilled in the art, refrigeration system 60 may include additional components, e.g., at least one additional evaporator, compressor, expansion device, and / or condenser. As an example, refrigeration system 60 may include two evaporators.

[0027] Within refrigeration system 60, refrigerant flows into compressor 64, which operates to increase the pressure of the refrigerant. This compression of the refrigerant raises its temperature, which is lowered by passing the refrigerant through condenser 66. Within condenser 66, heat exchange with ambient air takes place so as to cool the refrigerant. A fan 72 is used to pull air across condenser 66, as illustrated by arrows AC, so as to provide forced convection for a more rapid and efficient heat exchange between the refrigerant within condenser 66 and the ambient air. Thus, as will be understood by those skilled in the art, increasing air flow across condenser 66 can, e.g., increase the efficiency of condenser 66 by improving cooling of the refrigerant contained therein.

[0028] An expansion device 68 (e.g., a valve, capillary tube, or other restriction device) receives refrigerant from condenser 66. From expansion device 68, the refrigerant enters evaporator 70. Upon exiting expansion device 68 and entering evaporator 70, the refrigerant drops in pressure. Due to the pressure drop and / or phase change of the refrigerant, evaporator 70 is cool relative to compartments 14 and 18 of refrigerator appliance 10. As such, cooled air is produced and refrigerates compartments 14 and 18 of refrigerator appliance 10. Thus, evaporator 70 is a type of heat exchanger which transfers heat from air passing over evaporator 70 to refrigerant flowing through evaporator 70.

[0029] Collectively, the vapor compression cycle components in a refrigeration circuit, associated fans, and associated compartments are sometimes referred to as a sealed refrigeration system operable to force cold air through compartments 14, 18 (FIG. 1). The refrigeration system 60 depicted in FIG. 2 is provided by way of example only. Thus, it is within the scope of the present subject matter for other configurations of the refrigeration system to be used as well.

[0030] Referring now generally to FIGS. 3 through 7, a compressor 100 will be described according to exemplary embodiments of the present subject matter. The illustrated example compressor 100 is a linear compressor, however, the present disclosure is not limited to linear compressors and may be used with any suitable compressor, such as a rotary compressor, a reciprocating compressor, or other similar compressors, e.g., any compressor which includes moving parts, a lubricant, and a pump for the lubricant. The compressor may be used in various sealed systems for appliances, such as the exemplary refrigerator appliance of FIGS. 1 and 2, a heat pump dryer appliance, an air conditioner appliances, or any other such appliance. Specifically, FIGS. 3 and 4 provide perspective, section views of compressor 100, FIG. 5 provides a perspective view of linear compressor 100 with a compressor shell or housing 102 removed for clarity, and FIGS. 6 and 7 provide section views of linear compressor when a piston is in an extended and retracted position, respectively. It should be appreciated that linear compressor 100 is used herein only as an exemplary embodiment to facilitate the description of aspects of the present subject matter. Modifications and variations may be made to compressor 100 while remaining within the scope of the present subject matter.

[0031] As illustrated for example in FIGS. 3 and 4, housing 102 may include a lower portion or lower housing 104 and an upper portion or upper housing 106 which are joined together to form a substantially enclosed cavity 108 for housing various components of linear compressor 100. Specifically, for example, cavity 108 may be a hermetic or air-tight shell that can house working components of linear compressor 100 and may hinder or prevent refrigerant from leaking or escaping from refrigeration system 60. In addition, linear compressor 100 generally defines an axial direction A, a radial direction R, and a circumferential direction C. It should be appreciated that linear compressor 100 is described and illustrated herein only to describe aspects of the present subject matter. Variations and modifications to linear compressor 100 may be made while remaining within the scope of the present subject matter.

[0032] Referring now generally to FIGS. 3 through 7, various parts and working components of linear compressor 100 will be described according to an exemplary embodiment. As shown, linear compressor 100 includes a casing 110 that extends between a first end portion 112 and a second end portion 114, e.g., along the axial direction A. Casing 110 includes a cylinder 117 that defines a chamber 118. Cylinder 117 is positioned at or adjacent first end portion 112 of casing 110. Chamber 118 extends longitudinally along the axial direction A. As discussed in greater detail below, linear compressor 100 is operable to increase a pressure of fluid within chamber 118 of linear compressor 100. Linear compressor 100 may be used to compress any suitable fluid, such as refrigerant or air. In particular, linear compressor 100 may be used in a refrigerator appliance, such as refrigerator appliance 10 (FIG. 1) in which linear compressor 100 may be used as compressor 64 (FIG. 2).

[0033] Linear compressor 100 includes a stator 120 of a motor that is mounted or secured to casing 110. For example, stator 120 generally includes an outer back iron 122 and a driving coil 124 that extend about the circumferential direction C within casing 110. Linear compressor 100 also includes one or more valves that permit refrigerant to enter and exit chamber 118 during operation of linear compressor 100. For example, a discharge valve 126 is positioned at an end of chamber 118 for regulating the flow of refrigerant out of chamber 118, while a suction valve 128 (shown only in FIGS. 6-7 for clarity) regulates flow of refrigerant into chamber 118.

[0034] A piston 130 with a piston head 132 is slidably received within chamber 118 of cylinder 117. In particular, piston 130 is slidable along the axial direction A. During sliding of piston head 132 within chamber 118, piston head 132 compresses refrigerant within chamber 118. As an example, from a top dead center position (see, e.g., FIG. 6), piston head 132 can slide within chamber 118 towards a bottom dead center position (see, e.g., FIG. 7) along the axial direction A, i.e., an expansion stroke of piston head 132. When piston head 132 reaches the bottom dead center position, piston head 132 changes directions and slides in chamber 118 back towards the top dead center position, i.e., a compression stroke of piston head 132. It should be understood that linear compressor 100 may include an additional piston head and / or additional chambers at an opposite end of linear compressor 100. Thus, linear compressor 100 may have multiple piston heads in alternative exemplary embodiments.

[0035] As illustrated, linear compressor 100 also includes a mover 140 which is generally driven by stator 120 for compressing refrigerant. Specifically, for example, mover 140 may include an inner back iron 142 positioned in stator 120 of the motor. In particular, outer back iron 122 and / or driving coil 124 may extend about inner back iron 142, e.g., along the circumferential direction C. Inner back iron 142 also has an outer surface that faces towards outer back iron 122 and / or driving coil 124. At least one driving magnet 144 is mounted to inner back iron 142, e.g., at the outer surface of inner back iron 142.

[0036] Driving magnet 144 may face and / or be exposed to driving coil 124. In particular, driving magnet 144 may be spaced apart from driving coil 124, e.g., along the radial direction R by an air gap. Thus, the air gap may be defined between opposing surfaces of driving magnet 144 and driving coil 124. Driving magnet 144 may also be mounted or fixed to inner back iron 142 such that an outer surface of driving magnet 144 is substantially flush with the outer surface of inner back iron 142. Thus, driving magnet 144 may be inset within inner back iron 142. In such a manner, the magnetic field from driving coil 124 may have to pass through only a single air gap between outer back iron 122 and inner back iron 142 during operation of linear compressor 100, and linear compressor 100 may be more efficient relative to linear compressors with air gaps on both sides of a driving magnet.

[0037] As may be seen in FIG. 3, driving coil 124 extends about inner back iron 142, e.g., along the circumferential direction C. In alternative example embodiments, inner back iron 142 may extend around driving coil 124 along the circumferential direction C. Driving coil 124 is operable to move the inner back iron 142 along the axial direction A during operation of driving coil 124. As an example, a current may be induced within driving coil 124 by a current source (not shown) to generate a magnetic field that engages driving magnet 144 and urges piston 130 to move along the axial direction A in order to compress refrigerant within chamber 118 as described above and will be understood by those skilled in the art. In particular, the magnetic field of driving coil 124 may engage driving magnet 144 in order to move inner back iron 142 and piston head 132 along the axial direction A during operation of driving coil 124. Thus, driving coil 124 may slide piston 130 between the top dead center position and the bottom dead center position, e.g., by moving inner back iron 142 along the axial direction A, during operation of driving coil 124.

[0038] Linear compressor 100 may include various components for permitting and / or regulating operation of linear compressor 100. In particular, linear compressor 100 includes a controller 250 (see FIG. 9) that is configured for regulating operation of linear compressor 100. The controller is in, e.g., operative, communication with the motor, e.g., driving coil 124 of the motor. Thus, the controller may selectively activate driving coil 124, e.g., by inducing current in driving coil 124, in order to compress refrigerant with piston 130 as described above.

[0039] The controller includes memory and one or more processing devices such as microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of linear compressor 100. The memory can represent random access memory such as DRAM, or read only memory such as ROM or FLASH. The processor executes programming instructions stored in the memory. The memory can be a separate component from the processor or can be included onboard within the processor. Alternatively, the controller may be constructed without using a microprocessor, e.g., using a combination of discrete analog and / or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.

[0040] Inner back iron 142 further includes an outer cylinder 146 and an inner sleeve 148. Outer cylinder 146 defines the outer surface of inner back iron 142 and also has an inner surface positioned opposite the outer surface of outer cylinder 146. Inner sleeve 148 is positioned on or at inner surface of outer cylinder 146. A first interference fit between outer cylinder 146 and inner sleeve 148 may couple or secure outer cylinder 146 and inner sleeve 148 together. In alternative exemplary embodiments, inner sleeve 148 may be welded, glued, fastened, or connected via any other suitable mechanism or method to outer cylinder 146.

[0041] Outer cylinder 146 may be constructed of or with any suitable material. For example, outer cylinder 146 may be constructed of or with a plurality of (e.g., ferromagnetic) laminations. The laminations are distributed along the circumferential direction C in order to form outer cylinder 146 and are mounted to one another or secured together, e.g., with rings pressed onto ends of the laminations. Outer cylinder 146 may define a recess that extends inwardly from the outer surface of outer cylinder 146, e.g., along the radial direction R. Driving magnet 144 is positioned in the recess on outer cylinder 146, e.g., such that driving magnet 144 is inset within outer cylinder 146.

[0042] Linear compressor 100 also includes a pair of planar springs 150. Each planar spring 150 may be coupled to a respective end of inner back iron 142, e.g., along the axial direction A. During operation of driving coil 124, planar springs 150 support inner back iron 142. In particular, inner back iron 142 is suspended by planar springs 150 within the stator or the motor of linear compressor 100 such that motion of inner back iron 142 along the radial direction R is hindered or limited while motion along the axial direction A is relatively unimpeded. Thus, planar springs 150 may be substantially stiffer along the radial direction R than along the axial direction A. In such a manner, planar springs 150 can assist with maintaining a uniformity of the air gap between driving magnet 144 and driving coil 124, e.g., along the radial direction R, during operation of the motor and movement of inner back iron 142 on the axial direction A. Planar springs 150 can also assist with hindering side pull forces of the motor from transmitting to piston 130 and being reacted in cylinder 117 as a friction loss.

[0043] A flex mount 160 is mounted to and extends through inner back iron 142. In particular, flex mount 160 is mounted to inner back iron 142 via inner sleeve 148. Thus, flex mount 160 may be coupled (e.g., threaded) to inner sleeve 148 at the middle portion of inner sleeve 148 and / or flex mount 160 in order to mount or fix flex mount 160 to inner sleeve 148. Flex mount 160 may assist with forming a coupling 162. Coupling 162 connects inner back iron 142 and piston 130 such that motion of inner back iron 142, e.g., along the axial direction A, is transferred to piston 130.

[0044] Coupling 162 may be a compliant coupling that is compliant or flexible along the radial direction R. In particular, coupling 162 may be sufficiently compliant along the radial direction R such that little or no motion of inner back iron 142 along the radial direction R is transferred to piston 130 by coupling 162. In such a manner, side pull forces of the motor are decoupled from piston 130 and / or cylinder 117 and friction between piston 130 and cylinder 117 may be reduced.

[0045] As may be seen in the figures, piston head 132 of piston 130 has a cylindrical side wall 170. Cylindrical side wall 170 may extend along the axial direction A from piston head 132 towards inner back iron 142. An outer surface of cylindrical side wall 170 may slide on cylinder 117 at chamber 118 and an inner surface of cylindrical side wall 170 may be positioned opposite the outer surface of cylindrical side wall 170. Thus, the outer surface of cylindrical side wall 170 may face away from a center of cylindrical side wall 170 along the radial direction R, and the inner surface of cylindrical side wall 170 may face towards the center of cylindrical side wall 170 along the radial direction R.

[0046] Flex mount 160 extends between a first end portion 172 and a second end portion 174, e.g., along the axial direction A. According to an exemplary embodiment, the inner surface of cylindrical side wall 170 defines a ball seat 176 proximate first end portion. In addition, coupling 162 also includes a ball nose 178. Specifically, for example, ball nose 178 is positioned at first end portion 172 of flex mount 160, and ball nose 178 may contact flex mount 160 at first end portion 172 of flex mount 160. In addition, ball nose 178 may contact piston 130 at ball seat 176 of piston 130. In particular, ball nose 178 may rest on ball seat 176 of piston 130 such that ball nose 178 is slidable and / or rotatable on ball seat 176 of piston 130. For example, ball nose 178 may have a frusto-spherical surface positioned against ball seat 176 of piston 130, and ball seat 176 may be shaped complementary to the frusto-spherical surface of ball nose 178. The frusto-spherical surface of ball nose 178 may slide and / or rotate on ball seat 176 of piston 130.

[0047] Relative motion between flex mount 160 and piston 130 at the interface between ball nose 178 and ball seat 176 of piston 130 may provide reduced friction between piston 130 and cylinder 117, e.g., compared to a fixed connection between flex mount 160 and piston 130. For example, when an axis on which piston 130 slides within cylinder 117 is angled relative to the axis on which inner back iron 142 reciprocates, the frusto-spherical surface of ball nose 178 may slide on ball seat 176 of piston 130 to reduce friction between piston 130 and cylinder 117 relative to a rigid connection between inner back iron 142 and piston 130.

[0048] Flex mount 160 is connected to inner back iron 142 away from first end portion 172 of flex mount 160. For example, flex mount 160 may be connected to inner back iron 142 at second end portion 174 of flex mount 160 or between first and second end portions 172, 174 of flex mount 160. Conversely, flex mount 160 is positioned at or within piston 130 at first end portion 172 of flex mount 160, as discussed in greater detail below.

[0049] In addition, flex mount 160 includes a tubular wall 190 between inner back iron 142 and piston 130. A channel 192 within tubular wall 190 is configured for directing compressible fluid, such as refrigerant or air, though flex mount 160 towards piston head 132 and / or into piston 130. Inner back iron 142 may be mounted to flex mount 160 such that inner back iron 142 extends around tubular wall 190, e.g., at the middle portion of flex mount 160 between first and second end portions 172, 174 of flex mount 160. Channel 192 may extend between first and second end portions 172, 174 of flex mount 160 within tubular wall 190 such that the compressible fluid is flowable from first end portion 172 of flex mount 160 to second end portion 174 of flex mount 160 through channel 192. In such a manner, compressible fluid may flow through inner back iron 142 within flex mount 160 during operation of linear compressor 100. A muffler 194 may be positioned within channel 192 within tubular wall 190, e.g., to reduce the noise of compressible fluid flowing through channel 192.

[0050] Piston head 132 also defines at least one opening 196. Opening 196 of piston head 132 extends, e.g., along the axial direction A, through piston head 132. Thus, the flow of fluid may pass through piston head 132 via opening 196 of piston head 132 into chamber 118 during operation of linear compressor 100. In such a manner, the flow of fluid (that is compressed by piston head 132 within chamber 118) may flow within channel 192 through flex mount 160 and inner back iron 142 to piston 130 during operation of linear compressor 100. As explained above, suction valve 128 (FIGS. 6-7) may be positioned on piston head 132 to regulate the flow of compressible fluid through opening 196 into chamber 118.

[0051] Referring still to FIGS. 3 through 7, and now also referring to FIG. 8, a lubrication system 200 will be described which may be used with linear compressor 100. Specifically, lubrication system 200 is configured for circulating a lubricant, e.g., such as oil, through the working or moving components of linear compressor 100 to reduce friction, improve efficiency, etc. Although lubrication system 200 is described herein with respect to linear compressor 100, it should be appreciated that aspects of lubrication system 200 may apply to any other suitable compressor or machine that requires continuous lubrication.

[0052] Notably, linear compressor 100 is commonly filled with a predetermined volume of lubricant 204, e.g., based on the lubrication needs and pump positioning of the linear compressor 100. It may be desirable to ensure that pump inlet 208 remains submerged in lubricant 204 throughout operation of linear compressor 100, e.g., to prevent unlubricated compressor operation and potential compressor damage, noise, etc. Accordingly, housing 102 may generally define a lubricant fill line 212 to which lubricant 204 is added to ensure proper, safe operation of linear compressor 100. According to exemplary embodiments, pump inlet 208 is positioned below lubricant fill line 212, e.g., such that pump inlet 208 is submerged by at least 1 mm, at least 3 mm, at least 5 mm, at least 10 mm, or greater.

[0053] As shown, housing 102 generally defines a sump 202 which is configured for collecting oil (e.g., as identified herein by reference numeral 204, see FIG. 8). Specifically, sump 202 is defined in the bottom portion of lower housing 104. Lubrication system 200 further includes a pump 206 for continuously circulating oil 204 through components of linear compressor 100 which need lubrication. In this regard, for example, pump 206 may include a pump inlet 208 positioned proximate bottom of housing 102 within sump 202. Pump 206 may draw in oil 204 from sump 202 through pump inlet 208 before circulating it throughout linear compressor 100, e.g., via a supply conduit 210. Although only one supply conduit 210 is shown in the figures for clarity, it should be appreciated that lubrication system 200 may include any suitable number of supply conduits, nozzles, and other distribution features in order to provide oil 204 to various components throughout linear compressor 100.

[0054] Notably, according to the illustrated embodiment, pump inlet 208 is positioned very near and faces the bottom of lower housing 104. In this manner, pump 206 may readily draw in oil 204 even when oil levels are low. Specifically, linear compressor 100 may be configured for receiving oil 204 not to exceed a max oil fill line 212. For example, the max oil fill line 212 is identified in FIGS. 6-8, and may for example extend less than half the way up lower housing 104, less than a quarter of the way up lower housing 104, or lower. During operation, pump 206 may circulate oil 204 throughout linear compressor 100, after which the oil 204 will seep or flow out of the working components and collect in sump 202 before being recirculated. Although not illustrated here, it should be appreciated that lubrication system 200 may include various features for treating, filtering, or conditioning oil 204 during recirculation, such as various filters, screens, etc. In addition, it should be appreciated that although pump 206 is illustrated as being positioned within sump 202, it could be positioned at any other location and may include a fluid passage that draws oil 204 from sump 202.

[0055] As also illustrated in the figures, linear compressor 100 may include a suction inlet 220 for receiving a flow of refrigerant. Specifically, suction inlet 220 may be defined on housing 102 (e.g., such as on lower housing 104), and may be configured for receiving a refrigerant supply conduit to provide refrigerant to cavity 108. As explained above, flex mount 160 includes tubular wall 190, which defines channel 192 for directing compressible fluid, such as refrigerant gas, through flex mount 160 towards piston head 132. In this manner, desirable flow path of refrigerant gas is through suction inlet 220, through channel 192, through opening 196, and into chamber 118. Suction valve 128 may block opening 196 during a compression stroke and a discharge valve 116 may permit the compressed gas to exit chamber 118 when the desired pressure is reached.

[0056] Flex mount 160 may further define a channel inlet 230 which is positioned proximate a second end portion 174 of flex mount 160 for drawing gas and from suction inlet 220 or cavity 108 into channel 192. Specifically, channel inlet 230 may be an opening on flex mount 160 which extends substantially within a vertical plane and opens toward suction inlet 220. Specifically, according to the illustrated embodiment, channel inlet 230 and suction inlet 220 may be positioned substantially within the same horizontal plane. According to the illustrated embodiment, suction inlet 220 and channel inlet 230 are also positioned proximate a midpoint of housing 102 along a vertical direction V. However, it should be appreciated that according to alternative embodiments, suction inlet 220 and channel inlet 230 may be positioned at any other suitable locations within housing 102.

[0057] As mentioned above, it may be desirable to ensure that pump inlet 208 remains submerged in lubricant 204 throughout operation of linear compressor 100. In some instances, it may be difficult to maintain submersion of the pump inlet 208 within the lubricant 204. For example, if the compressor is tipped over or out of level, the oil 204 may slosh or otherwise flow away from the pump inlet 208. Such tipping may occur, for example, when the compressor is incorporated into a refrigerator appliance or other appliance in a recreational vehicle (RV) and during driving the RV on steep slopes. As another example, the compressor may be incorporated into an appliance which is installed out of level, such as on a sloped floor or other substrate.

[0058] In various examples, the out of level condition of the compressor may be a transient condition or a persistent condition, where a persistent out of level condition may include the lubricant flowing away from the pump inlet in a single linear and / or angular direction, and a transient out of level condition may include the lubricant sloshing back and forth in multiple directions relative to the pump inlet. For example, in an appliance in an RV, a persistent out of level condition may occur when driving on a steady and steep slope, where the compressor may be out of level in a single orientation (e.g., linear and / or angular) from the level position and the compressor may maintain such position for an extended period of time, such as at least about one second, such as at least about five seconds, such as at least about ten seconds. The single orientation as used herein includes the compressor in the same orientation (e.g., the same direction, although the distance from level may vary) away from the level position. In another example, continuing with reference to a compressor for an appliance in an RV, a transient out of level condition may occur, e.g., when driving over rough uneven roads or other surfaces, such that the compressor deviates from level in two or more different linear and / or angular directions within a relatively short time frame, such as maintaining any one direction from level for about ten seconds or less, such as about five seconds or less, such as about one second or less. For example, a transient out of level condition may include the compressor out of level in a first direction (such as a clockwise angle or above level along a linear axis) followed by returning to level and / or moving out of level in a second direction different from the first direction (such as a counterclockwise angle or below level along the linear axis).

[0059] FIG. 9 provides a schematic illustration of an exemplary compressor 100, e.g., the linear compressor described above or another suitable compressor (which may be, for example, a rotary compressor or a reciprocating compressor among other possible variations). As mentioned above, the compressor 100 may include a controller 250. Further, the controller 250 may be in communication with a measurement device 280 via one or more signal lines or shared communication busses. Optionally, measurement device 280 may be included with (e.g., integrated on-board) the controller 250. Moreover, measurement devices 280 may include a microprocessor that performs the calculations specific to the measurement of motion, position, and / or orientation with the calculation results being used by controller 250.

[0060] As illustrated in FIG. 9, one or more measurement devices 280 may be provided in or on the compressor 100, such as the compressor 100 may include an electrical box 260 mounted to the casing 102, and the electrical box 260 may house one or both of the controller 250 and the measurement device 280. The measurement device(s) 280 may be operable for measuring movement of the compressor 100, such as movement of the compressor 100 as a whole, such as shifting or tipping away from a level condition, and / or position or orientation of the compressor 100, such as a non-level position. Measurement devices 280 may measure a variety of suitable variables that can be correlated to movement and / or position of the compressor 100. The measurements obtained by such devices 280 can be utilized to monitor the level or balance state of the compressor 100 (e.g., to ensure that the compressor 100 does not tip over such that the pump inlet 208 is no longer submerged, and / or to detect such condition and take remedial actions in response).

[0061] A measurement device 280 in accordance with the present disclosure may include an accelerometer which measures translational motion, such as acceleration along one or more directions. Additionally or alternatively, a measurement device 280 may include a gyroscope, which measures rotational motion, such as rotational velocity about an axis. Additionally or alternatively, a measurement device 280 may include a magnetometer, which is responsive to geomagnetic fields. For example, the magnetometer may be used to measure a strength of the geomagnetic fields, e.g., a geomagnetic flux, and, based on the strength of the geomagnetic fields and / or changes therein, determine or estimate an orientation relative to the pull of gravity and / or changes in such orientation. In particular, a measurement device 280 may include all three (e.g., at least one of each) of an accelerometer, a gyroscope, and a magnetometer. A measurement device 280 in accordance with the present disclosure is mounted to the casing 102 (e.g., on an outer surface of the casing 102, such as in the electrical box 260 thereon) to sense movement and / or position of the compressor 100. For instance, movement may be measured as discrete identifiable components (e.g., in a predetermined direction) within a coordinate system defined by an X-axis, a Y-axis, and a Z-axis, where the X-axis, Y-axis, and Z-axis are each mutually perpendicular. For example, the Y-axis may be generally parallel to the axial direction A (FIGS. 3-5).

[0062] In exemplary embodiments, a measurement device 280 may include at least one gyroscope, at least one accelerometer, and / or at least one magnetometer. The measurement device 280, for example, may be a printed circuit board that includes the gyroscope, accelerometer, and magnetometer thereon. The measurement device 280 may be mounted to the casing 102 (e.g., via a suitable mechanical fastener, adhesive, etc.) and may be oriented such that the various sub-components (e.g., the gyroscope, accelerometer, and magnetometer) are oriented to measure movement along or about particular directions as discussed herein. Notably, the gyroscope, accelerometer, and magnetometer in exemplary embodiments are advantageously mounted to the casing 102 at a single location (e.g., the location of the printed circuit board or other component of the measurement device 280 on which the gyroscope, accelerometer, and magnetometer are grouped). Such positioning at a single location advantageously reduces the costs and complexity (e.g., due to additional wiring, etc.) of out-of-level detection, while still providing relatively accurate detection as discussed herein. Alternatively, however, the gyroscope and accelerometer need not be mounted at a single location. For example, a gyroscope located at one location on casing 102 can measure the rotation of an accelerometer located at a different location on casing 102, because rotation about a given axis is the same everywhere on a solid object such as casing 102.

[0063] In some embodiments, movement is measured as a plurality of unique displacement values. Optionally, the displacement values may occur in discrete channels of motion (e.g., as distinct directional components of movement). For instance, displacement values may correspond to one or more indirectly measured movement components perpendicular or approximately perpendicular to a center G (e.g., geometric center of gravity based on the shape and mass of the compressor 100) of the compressor 100. Such movement components may, for example, occur in a plane defined by the X-axis and the Z-axis (i.e., the X-Z plane) or in a plane perpendicular to the X-Y plane, e.g., a plane defined by the Y-axis and the Z-axis (i.e., the Y-Z plane). Movement of the compressor 100 along the particular direction may be calculated using the indirect measurement component and other suitable variables, such as an axial and / or radial offset distance along the vector from the measurement device 280 to the center G of the casing 102. Additionally or alternatively, the displacement values may correspond to one or more directly measured movement components. Such movement components may, for example, occur in the X-Z plane or in the Y-Z plane.

[0064] Notably, the term “approximately” as utilized with regard to the orientation and position of such movement measurements denotes ranges such as of plus or minus 2 inches or plus or minus 10 degrees relative to various axes passing through the center G of the compressor 100.

[0065] In some embodiments, an out-of-level condition may be determined, at least in part, from the measurements obtained by measurement device 280. For instance, controller 250 may correlate displacement (e.g., one or more linear and / or angular displacement) values to an out of level condition, such as when one or more displacements exceeds a threshold or tolerance limit. As mentioned above, the out of level condition may be persistent (e.g., linear and / or angular displacement exceeding the threshold in a single direction throughout a period of time) or transitory (e.g., multiple linear and / or angular displacements exceeding respective thresholds in different directions within the period of time).

[0066] Now that the descriptions of an exemplary compressor, as well as a sealed system and appliance into which the compressor may be incorporated, have been provided, a method 300 of operating a compressor, such as but not limited to compressor 100, will be described. Although the discussion below refers to the exemplary method 300 of operating compressor 100, one skilled in the art will appreciate that the exemplary method 300 is applicable to any suitable compressor, and that such compressors may be incorporated into a variety of domestic appliances or household appliances, e.g., a refrigerator appliance, an air conditioner appliance, a clothes dryer appliance, and other such appliances. In exemplary embodiments, the various method steps as disclosed herein may be performed by controller 250 and / or a separate, dedicated controller. FIG. 10 provides a flow chart illustrating a method of operating a compressor. Hereinafter, method 300 will be described with specific reference to FIG. 10.

[0067] As noted above, method 300 may be practiced with any suitable compressor, such as the exemplary compressor 100 described above. More particularly, the compressor may include a housing defining a sump for collecting lubricant and a pump for circulating the lubricant within the housing. The pump may include a lubricant intake tube defining a pump inlet positioned within the sump. The compressor may further include a measurement device.

[0068] As illustrated in FIG. 10, method 300 may include (310) operating the compressor to increase the pressure and temperature of a refrigerant. Method 300 may further include (320) detecting, with the measurement device, a position of the compressor while operating the compressor. For example, the position of the compressor may be determined with reference to a certain predefined angle (e.g., with respect to a horizontal plane, such as the X-Y plane, e.g., as indicated in FIG. 9). When the measurement device determines that the compressor is at or past the predefined angle, the oil pump (e.g., the inlet thereof) can be determined to be out of the oil (e.g., at least partially above a level of the oil or lubricant) and therefore not supplying lubrication to the moving compressor parts. The predefined angle may be defined in any suitable plane, such as the X-Z plane or the Y-Z plane as described above, and / or relative to a horizontal direction or horizontal plane. In some embodiments, multiple predefined limit angles may be defined in various planes, and the compressor may be shut down in response to detecting a position of the compressor (e.g., with the measurement device) that is at or above any one or more of the multiple predefined limit angles (such angles being defined in diverse planes). The position of the compressor may also or instead be determined with reference to a predetermined degree of rotation, such as rotation about the X-axis or the Y-axis, the axial direction A, and / or one or more other axes of rotation which are generally perpendicular to the vertical direction V (e.g., FIGS. 1 and 3) and / or the Z-axis (e.g., FIG. 9). Further, the position of the compressor may also or instead be determined with reference to geomagnetic fields, e.g., using the magnetometer to determine an orientation of the compressor relative to the pull of Earth's gravity.

[0069] Accordingly, the controller may be configured for, and / or method 300 may include, shutting down the compressor operation in response to the detected position of the compressor, as indicated at (330) in FIG. 10, e.g., deactivating the compressor when it gets past the predefined angle, degree of rotation, and / or geomagnetic orientation. In various embodiments, the controller may be configured for, and / or the method 300 may include, shutting the compressor down until the oil level is acceptable (e.g., as determined based on the position of the compressor, e.g., returning below the predetermined limit angle, degree of rotation and / or geomagnetic flux, and which may also include a settling time after returning to a generally level position to allow the lubricant to fully flow back down into the sump). The controller may also be configured for, and / or the method 300 may also include, shutting the compressor down until there is a call for heating or colling, such as when temperatures in the refrigerator (in example embodiments where the compressor is coupled to a sealed system of a refrigerator appliance) gets unacceptably high.

[0070] For example, in some embodiments, the detected position in response to which the compressor is deactivated may be an out-of-level position, e.g., a persistent or transitory out-of-level position, as described above. When the compressor is in the out-of-level position, the pump inlet may be at least partially above a lubricant level within the sump, such as a center of the pump inlet may be above the lubricant level, or such as the pump inlet may be fully above the lubricant level where the entire pump inlet is outside of the lubricant. For example, the lubricant level may be a maximum lubricant level or a top of a volume of lubricant, e.g., at or approximately at the fill line 212 (see, e.g., FIGS. 6-8).

[0071] In some embodiments, the compressor may be reactivated when the compressor returns to a level position, or at least within a tolerance range of the level position, e.g., at an angle, degree of rotation, and / or geomagnetic flux less than the predefined limit(s) mentioned above. For example, methods according to the present subject matter, such as method 300, may further include (where the detected position of the compressor is a first detected position) detecting, with the measurement device, a second position of the compressor after the first detected position. Such embodiments may further include reactivating the compressor in response to the second detected position of the compressor. In such embodiments, the first detected position of the compressor may be an out-of-level position (e.g., at or above the predefined limit in one direction (e.g., a persistent out-of-level) or in multiple different directions (e.g., a transitory out-of-level)) and the second detected position of the compressor may be a level position (e.g., below the predefined limit).

[0072] In some embodiments, the compressor may be reactivated in response to a call for heating or cooling, e.g., when the compressor is coupled to a sealed system such as the exemplary sealed system illustrated in FIG. 2 (and even if the compressor has not yet returned to a level position). For example, in embodiments where the sealed system is incorporated into a refrigerator appliance, preserving food within the chilled chamber(s) of the refrigerator appliance may take precedence over the oil level, e.g., when the temperature in the chilled chamber(s) exceeds a predefined safety factor or threshold away from (e.g., above, in this example) a target temperature, e.g., to prevent food spoiling and / or to maintain a temperature within a food storage compartment at or below a maximum safe temperature. Thus, in some embodiments, e.g., the controller may be configured for, and / or the method may include, reactivating the compressor in response to a call for cooling. In such embodiments, the compressor may be coupled to a sealed system of a refrigerator appliance, and the call for cooling may be based on a set temperature of a chilled chamber of the refrigerator appliance.

[0073] The written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Examples

Embodiment Construction

[0022]Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0023]As used herein, terms of approximation, such as “generally,” or “about” include values within ten percent greater or less than the stated value. When used in the context of an angle or direction, such terms include within ten degrees greater or less t...

FIELD OF THE INVENTION

[0001] The present subject matter relates generally to compressors and sensors for compressors.BACKGROUND OF THE INVENTION

[0002] Certain appliances, e.g., refrigerators include sealed systems for heating and / or cooling a fluid, such as generating a flow of cooled air for chilled chambers of the refrigerator appliance, heating or cooling air with an air conditioner appliance, and / or heating air in a clothes dryer appliance. The sealed systems generally include a compressor that generates compressed refrigerant during operation of the sealed system. The compressed refrigerant flows to an evaporator where heat exchange between the refrigerant and another fluid, e.g., air, which may be useful for, e.g., in the refrigerator appliance example, cooling the chilled chambers and food items located therein.

[0003] An oil supply system is typically included within the compressor housing for lubricating moving parts thereof, such as a piston in a linear compressor or a rotor in a rotary compressor, to reduce friction losses (e.g., between the piston and a chamber wall in a linear compressor or between rotor vanes in a rotary compressor) which can negatively affect an efficiency of an associated sealed system and appliance, e.g., refrigerator appliance.

[0004] The oil supply system typically includes a reservoir or sump in which a volume of oil is retained and from which the oil is drawn by a pump for circulation within the compressor, e.g., between moving parts as mentioned. In some cases, however, an inlet of the pump may not be fully submerged within the volume of oil in the sump. For example, when the compressor is tipped or out of level, the volume of oil in the sump may flow away from the inlet of the pump. Thus, the pump may not be able to supply oil to fully lubricate the moving parts, or other issues such as cavitation of air bubbles within the pump may arise.

[0005] Accordingly, systems and methods for detecting such conditions in a compressor would be useful.BRIEF DESCRIPTION OF THE INVENTION

[0006] Aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

[0007] In an example embodiment, a compressor is provided. The compressor includes a housing defining a sump for collecting lubricant and a pump for circulating the lubricant within the housing. The pump includes a lubricant intake tube defining a pump inlet positioned within the sump. The compressor also includes a measurement device and a controller in operative communication with the measurement device. the controller is configured for operating the compressor to increase the pressure and temperature of a refrigerant and detecting, with the measurement device, a position of the compressor while operating the compressor. The controller is also configured for deactivating the compressor in response to the detected position of the compressor.

[0008] In another example embodiment, a method of operating a compressor is provided. The compressor includes a housing defining a sump for collecting lubricant and a pump for circulating the lubricant within the housing. The pump includes a lubricant intake tube defining a pump inlet positioned within the sump. The compressor also includes a measurement device. The method includes operating the compressor to increase the pressure and temperature of a refrigerant and detecting, with the measurement device, a position of the compressor while operating the compressor. The method further includes deactivating the compressor in response to the detected position of the compressor.

[0009] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

[0011] FIG. 1 is a front elevation view of a refrigerator appliance according to an example embodiment of the present subject matter.

[0012] FIG. 2 is schematic view of certain components of the example refrigerator appliance of FIG. 1.

[0013] FIG. 3 is a perspective, section view of an exemplary compressor according to one or more exemplary embodiments of the present subject matter.

[0014] FIG. 4 is another perspective, section view of the exemplary compressor of FIG. 3 according to one or more exemplary embodiments of the present subject matter.

[0015] FIG. 5 is a perspective view of a compressor with a compressor housing removed for clarity according to one or more exemplary embodiments of the present subject matter.

[0016] FIG. 6 is a section view of the exemplary compressor of FIG. 3 with a piston in an extended position according to an exemplary embodiment of the present subject matter.

[0017] FIG. 7 is a section view of the exemplary compressor of FIG. 3 with the piston in a retracted position according to an exemplary embodiment of the present subject matter.

[0018] FIG. 8 provides a schematic, cross sectional view of the exemplary compressor of FIG. 3 according to an exemplary embodiment of the present subject matter.

[0019] FIG. 9 provides a schematic perspective view of an exemplary compressor including a measurement device, according to one or more embodiments of the present subject matter.

[0020] FIG. 10 provides a flow chart diagram of an exemplary method of operation a compressor according to one or more embodiments of the present subject matter.

[0021] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.DETAILED DESCRIPTION

[0022] Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0023] As used herein, terms of approximation, such as “generally,” or “about” include values within ten percent greater or less than the stated value. When used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction. For example, “generally vertical” includes directions within ten degrees of vertical in any direction, e.g., clockwise or counter-clockwise.

[0024] FIG. 1 depicts a refrigerator appliance 10 that incorporates a sealed refrigeration system 60 (FIG. 2). It should be appreciated that the term “refrigerator appliance” is used in a generic sense herein to encompass any manner of refrigeration appliance, such as a freezer, refrigerator / freezer combination, and any style or model of conventional refrigerator. In addition, it should be understood that the present subject matter is not limited to use in appliances. Thus, the present subject matter may be used for any other suitable purpose, such as vapor compression within air conditioning units or air compression within air compressors.

[0025] In the illustrated example embodiment shown in FIG. 1, the refrigerator appliance 10 is depicted as an upright refrigerator having a cabinet or casing 12 that defines a number of internal chilled storage compartments. In particular, refrigerator appliance 10 includes upper fresh-food compartments 14 having doors 16 and lower freezer compartment 18 having upper drawer 20 and lower drawer 22. The drawers 20 and 22 are “pull-out” drawers in that they can be manually moved into and out of the freezer compartment 18 on suitable slide mechanisms.

[0026] FIG. 2 is a schematic view of certain components of refrigerator appliance 10, including a sealed refrigeration system 60 of refrigerator appliance 10. A machinery compartment 62 contains components for executing a known vapor compression cycle for cooling air. The components include a compressor 64, a condenser 66, an expansion device 68, and an evaporator 70 connected in series and charged with a refrigerant. As will be understood by those skilled in the art, refrigeration system 60 may include additional components, e.g., at least one additional evaporator, compressor, expansion device, and / or condenser. As an example, refrigeration system 60 may include two evaporators.

[0027] Within refrigeration system 60, refrigerant flows into compressor 64, which operates to increase the pressure of the refrigerant. This compression of the refrigerant raises its temperature, which is lowered by passing the refrigerant through condenser 66. Within condenser 66, heat exchange with ambient air takes place so as to cool the refrigerant. A fan 72 is used to pull air across condenser 66, as illustrated by arrows AC, so as to provide forced convection for a more rapid and efficient heat exchange between the refrigerant within condenser 66 and the ambient air. Thus, as will be understood by those skilled in the art, increasing air flow across condenser 66 can, e.g., increase the efficiency of condenser 66 by improving cooling of the refrigerant contained therein.

[0028] An expansion device 68 (e.g., a valve, capillary tube, or other restriction device) receives refrigerant from condenser 66. From expansion device 68, the refrigerant enters evaporator 70. Upon exiting expansion device 68 and entering evaporator 70, the refrigerant drops in pressure. Due to the pressure drop and / or phase change of the refrigerant, evaporator 70 is cool relative to compartments 14 and 18 of refrigerator appliance 10. As such, cooled air is produced and refrigerates compartments 14 and 18 of refrigerator appliance 10. Thus, evaporator 70 is a type of heat exchanger which transfers heat from air passing over evaporator 70 to refrigerant flowing through evaporator 70.

[0029] Collectively, the vapor compression cycle components in a refrigeration circuit, associated fans, and associated compartments are sometimes referred to as a sealed refrigeration system operable to force cold air through compartments 14, 18 (FIG. 1). The refrigeration system 60 depicted in FIG. 2 is provided by way of example only. Thus, it is within the scope of the present subject matter for other configurations of the refrigeration system to be used as well.

[0030] Referring now generally to FIGS. 3 through 7, a compressor 100 will be described according to exemplary embodiments of the present subject matter. The illustrated example compressor 100 is a linear compressor, however, the present disclosure is not limited to linear compressors and may be used with any suitable compressor, such as a rotary compressor, a reciprocating compressor, or other similar compressors, e.g., any compressor which includes moving parts, a lubricant, and a pump for the lubricant. The compressor may be used in various sealed systems for appliances, such as the exemplary refrigerator appliance of FIGS. 1 and 2, a heat pump dryer appliance, an air conditioner appliances, or any other such appliance. Specifically, FIGS. 3 and 4 provide perspective, section views of compressor 100, FIG. 5 provides a perspective view of linear compressor 100 with a compressor shell or housing 102 removed for clarity, and FIGS. 6 and 7 provide section views of linear compressor when a piston is in an extended and retracted position, respectively. It should be appreciated that linear compressor 100 is used herein only as an exemplary embodiment to facilitate the description of aspects of the present subject matter. Modifications and variations may be made to compressor 100 while remaining within the scope of the present subject matter.

[0031] As illustrated for example in FIGS. 3 and 4, housing 102 may include a lower portion or lower housing 104 and an upper portion or upper housing 106 which are joined together to form a substantially enclosed cavity 108 for housing various components of linear compressor 100. Specifically, for example, cavity 108 may be a hermetic or air-tight shell that can house working components of linear compressor 100 and may hinder or prevent refrigerant from leaking or escaping from refrigeration system 60. In addition, linear compressor 100 generally defines an axial direction A, a radial direction R, and a circumferential direction C. It should be appreciated that linear compressor 100 is described and illustrated herein only to describe aspects of the present subject matter. Variations and modifications to linear compressor 100 may be made while remaining within the scope of the present subject matter.

[0032] Referring now generally to FIGS. 3 through 7, various parts and working components of linear compressor 100 will be described according to an exemplary embodiment. As shown, linear compressor 100 includes a casing 110 that extends between a first end portion 112 and a second end portion 114, e.g., along the axial direction A. Casing 110 includes a cylinder 117 that defines a chamber 118. Cylinder 117 is positioned at or adjacent first end portion 112 of casing 110. Chamber 118 extends longitudinally along the axial direction A. As discussed in greater detail below, linear compressor 100 is operable to increase a pressure of fluid within chamber 118 of linear compressor 100. Linear compressor 100 may be used to compress any suitable fluid, such as refrigerant or air. In particular, linear compressor 100 may be used in a refrigerator appliance, such as refrigerator appliance 10 (FIG. 1) in which linear compressor 100 may be used as compressor 64 (FIG. 2).

[0033] Linear compressor 100 includes a stator 120 of a motor that is mounted or secured to casing 110. For example, stator 120 generally includes an outer back iron 122 and a driving coil 124 that extend about the circumferential direction C within casing 110. Linear compressor 100 also includes one or more valves that permit refrigerant to enter and exit chamber 118 during operation of linear compressor 100. For example, a discharge valve 126 is positioned at an end of chamber 118 for regulating the flow of refrigerant out of chamber 118, while a suction valve 128 (shown only in FIGS. 6-7 for clarity) regulates flow of refrigerant into chamber 118.

[0034] A piston 130 with a piston head 132 is slidably received within chamber 118 of cylinder 117. In particular, piston 130 is slidable along the axial direction A. During sliding of piston head 132 within chamber 118, piston head 132 compresses refrigerant within chamber 118. As an example, from a top dead center position (see, e.g., FIG. 6), piston head 132 can slide within chamber 118 towards a bottom dead center position (see, e.g., FIG. 7) along the axial direction A, i.e., an expansion stroke of piston head 132. When piston head 132 reaches the bottom dead center position, piston head 132 changes directions and slides in chamber 118 back towards the top dead center position, i.e., a compression stroke of piston head 132. It should be understood that linear compressor 100 may include an additional piston head and / or additional chambers at an opposite end of linear compressor 100. Thus, linear compressor 100 may have multiple piston heads in alternative exemplary embodiments.

[0035] As illustrated, linear compressor 100 also includes a mover 140 which is generally driven by stator 120 for compressing refrigerant. Specifically, for example, mover 140 may include an inner back iron 142 positioned in stator 120 of the motor. In particular, outer back iron 122 and / or driving coil 124 may extend about inner back iron 142, e.g., along the circumferential direction C. Inner back iron 142 also has an outer surface that faces towards outer back iron 122 and / or driving coil 124. At least one driving magnet 144 is mounted to inner back iron 142, e.g., at the outer surface of inner back iron 142.

[0036] Driving magnet 144 may face and / or be exposed to driving coil 124. In particular, driving magnet 144 may be spaced apart from driving coil 124, e.g., along the radial direction R by an air gap. Thus, the air gap may be defined between opposing surfaces of driving magnet 144 and driving coil 124. Driving magnet 144 may also be mounted or fixed to inner back iron 142 such that an outer surface of driving magnet 144 is substantially flush with the outer surface of inner back iron 142. Thus, driving magnet 144 may be inset within inner back iron 142. In such a manner, the magnetic field from driving coil 124 may have to pass through only a single air gap between outer back iron 122 and inner back iron 142 during operation of linear compressor 100, and linear compressor 100 may be more efficient relative to linear compressors with air gaps on both sides of a driving magnet.

[0037] As may be seen in FIG. 3, driving coil 124 extends about inner back iron 142, e.g., along the circumferential direction C. In alternative example embodiments, inner back iron 142 may extend around driving coil 124 along the circumferential direction C. Driving coil 124 is operable to move the inner back iron 142 along the axial direction A during operation of driving coil 124. As an example, a current may be induced within driving coil 124 by a current source (not shown) to generate a magnetic field that engages driving magnet 144 and urges piston 130 to move along the axial direction A in order to compress refrigerant within chamber 118 as described above and will be understood by those skilled in the art. In particular, the magnetic field of driving coil 124 may engage driving magnet 144 in order to move inner back iron 142 and piston head 132 along the axial direction A during operation of driving coil 124. Thus, driving coil 124 may slide piston 130 between the top dead center position and the bottom dead center position, e.g., by moving inner back iron 142 along the axial direction A, during operation of driving coil 124.

[0038] Linear compressor 100 may include various components for permitting and / or regulating operation of linear compressor 100. In particular, linear compressor 100 includes a controller 250 (see FIG. 9) that is configured for regulating operation of linear compressor 100. The controller is in, e.g., operative, communication with the motor, e.g., driving coil 124 of the motor. Thus, the controller may selectively activate driving coil 124, e.g., by inducing current in driving coil 124, in order to compress refrigerant with piston 130 as described above.

[0039] The controller includes memory and one or more processing devices such as microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of linear compressor 100. The memory can represent random access memory such as DRAM, or read only memory such as ROM or FLASH. The processor executes programming instructions stored in the memory. The memory can be a separate component from the processor or can be included onboard within the processor. Alternatively, the controller may be constructed without using a microprocessor, e.g., using a combination of discrete analog and / or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.

[0040] Inner back iron 142 further includes an outer cylinder 146 and an inner sleeve 148. Outer cylinder 146 defines the outer surface of inner back iron 142 and also has an inner surface positioned opposite the outer surface of outer cylinder 146. Inner sleeve 148 is positioned on or at inner surface of outer cylinder 146. A first interference fit between outer cylinder 146 and inner sleeve 148 may couple or secure outer cylinder 146 and inner sleeve 148 together. In alternative exemplary embodiments, inner sleeve 148 may be welded, glued, fastened, or connected via any other suitable mechanism or method to outer cylinder 146.

[0041] Outer cylinder 146 may be constructed of or with any suitable material. For example, outer cylinder 146 may be constructed of or with a plurality of (e.g., ferromagnetic) laminations. The laminations are distributed along the circumferential direction C in order to form outer cylinder 146 and are mounted to one another or secured together, e.g., with rings pressed onto ends of the laminations. Outer cylinder 146 may define a recess that extends inwardly from the outer surface of outer cylinder 146, e.g., along the radial direction R. Driving magnet 144 is positioned in the recess on outer cylinder 146, e.g., such that driving magnet 144 is inset within outer cylinder 146.

[0042] Linear compressor 100 also includes a pair of planar springs 150. Each planar spring 150 may be coupled to a respective end of inner back iron 142, e.g., along the axial direction A. During operation of driving coil 124, planar springs 150 support inner back iron 142. In particular, inner back iron 142 is suspended by planar springs 150 within the stator or the motor of linear compressor 100 such that motion of inner back iron 142 along the radial direction R is hindered or limited while motion along the axial direction A is relatively unimpeded. Thus, planar springs 150 may be substantially stiffer along the radial direction R than along the axial direction A. In such a manner, planar springs 150 can assist with maintaining a uniformity of the air gap between driving magnet 144 and driving coil 124, e.g., along the radial direction R, during operation of the motor and movement of inner back iron 142 on the axial direction A. Planar springs 150 can also assist with hindering side pull forces of the motor from transmitting to piston 130 and being reacted in cylinder 117 as a friction loss.

[0043] A flex mount 160 is mounted to and extends through inner back iron 142. In particular, flex mount 160 is mounted to inner back iron 142 via inner sleeve 148. Thus, flex mount 160 may be coupled (e.g., threaded) to inner sleeve 148 at the middle portion of inner sleeve 148 and / or flex mount 160 in order to mount or fix flex mount 160 to inner sleeve 148. Flex mount 160 may assist with forming a coupling 162. Coupling 162 connects inner back iron 142 and piston 130 such that motion of inner back iron 142, e.g., along the axial direction A, is transferred to piston 130.

[0044] Coupling 162 may be a compliant coupling that is compliant or flexible along the radial direction R. In particular, coupling 162 may be sufficiently compliant along the radial direction R such that little or no motion of inner back iron 142 along the radial direction R is transferred to piston 130 by coupling 162. In such a manner, side pull forces of the motor are decoupled from piston 130 and / or cylinder 117 and friction between piston 130 and cylinder 117 may be reduced.

[0045] As may be seen in the figures, piston head 132 of piston 130 has a cylindrical side wall 170. Cylindrical side wall 170 may extend along the axial direction A from piston head 132 towards inner back iron 142. An outer surface of cylindrical side wall 170 may slide on cylinder 117 at chamber 118 and an inner surface of cylindrical side wall 170 may be positioned opposite the outer surface of cylindrical side wall 170. Thus, the outer surface of cylindrical side wall 170 may face away from a center of cylindrical side wall 170 along the radial direction R, and the inner surface of cylindrical side wall 170 may face towards the center of cylindrical side wall 170 along the radial direction R.

[0046] Flex mount 160 extends between a first end portion 172 and a second end portion 174, e.g., along the axial direction A. According to an exemplary embodiment, the inner surface of cylindrical side wall 170 defines a ball seat 176 proximate first end portion. In addition, coupling 162 also includes a ball nose 178. Specifically, for example, ball nose 178 is positioned at first end portion 172 of flex mount 160, and ball nose 178 may contact flex mount 160 at first end portion 172 of flex mount 160. In addition, ball nose 178 may contact piston 130 at ball seat 176 of piston 130. In particular, ball nose 178 may rest on ball seat 176 of piston 130 such that ball nose 178 is slidable and / or rotatable on ball seat 176 of piston 130. For example, ball nose 178 may have a frusto-spherical surface positioned against ball seat 176 of piston 130, and ball seat 176 may be shaped complementary to the frusto-spherical surface of ball nose 178. The frusto-spherical surface of ball nose 178 may slide and / or rotate on ball seat 176 of piston 130.

[0047] Relative motion between flex mount 160 and piston 130 at the interface between ball nose 178 and ball seat 176 of piston 130 may provide reduced friction between piston 130 and cylinder 117, e.g., compared to a fixed connection between flex mount 160 and piston 130. For example, when an axis on which piston 130 slides within cylinder 117 is angled relative to the axis on which inner back iron 142 reciprocates, the frusto-spherical surface of ball nose 178 may slide on ball seat 176 of piston 130 to reduce friction between piston 130 and cylinder 117 relative to a rigid connection between inner back iron 142 and piston 130.

[0048] Flex mount 160 is connected to inner back iron 142 away from first end portion 172 of flex mount 160. For example, flex mount 160 may be connected to inner back iron 142 at second end portion 174 of flex mount 160 or between first and second end portions 172, 174 of flex mount 160. Conversely, flex mount 160 is positioned at or within piston 130 at first end portion 172 of flex mount 160, as discussed in greater detail below.

[0049] In addition, flex mount 160 includes a tubular wall 190 between inner back iron 142 and piston 130. A channel 192 within tubular wall 190 is configured for directing compressible fluid, such as refrigerant or air, though flex mount 160 towards piston head 132 and / or into piston 130. Inner back iron 142 may be mounted to flex mount 160 such that inner back iron 142 extends around tubular wall 190, e.g., at the middle portion of flex mount 160 between first and second end portions 172, 174 of flex mount 160. Channel 192 may extend between first and second end portions 172, 174 of flex mount 160 within tubular wall 190 such that the compressible fluid is flowable from first end portion 172 of flex mount 160 to second end portion 174 of flex mount 160 through channel 192. In such a manner, compressible fluid may flow through inner back iron 142 within flex mount 160 during operation of linear compressor 100. A muffler 194 may be positioned within channel 192 within tubular wall 190, e.g., to reduce the noise of compressible fluid flowing through channel 192.

[0050] Piston head 132 also defines at least one opening 196. Opening 196 of piston head 132 extends, e.g., along the axial direction A, through piston head 132. Thus, the flow of fluid may pass through piston head 132 via opening 196 of piston head 132 into chamber 118 during operation of linear compressor 100. In such a manner, the flow of fluid (that is compressed by piston head 132 within chamber 118) may flow within channel 192 through flex mount 160 and inner back iron 142 to piston 130 during operation of linear compressor 100. As explained above, suction valve 128 (FIGS. 6-7) may be positioned on piston head 132 to regulate the flow of compressible fluid through opening 196 into chamber 118.

[0051] Referring still to FIGS. 3 through 7, and now also referring to FIG. 8, a lubrication system 200 will be described which may be used with linear compressor 100. Specifically, lubrication system 200 is configured for circulating a lubricant, e.g., such as oil, through the working or moving components of linear compressor 100 to reduce friction, improve efficiency, etc. Although lubrication system 200 is described herein with respect to linear compressor 100, it should be appreciated that aspects of lubrication system 200 may apply to any other suitable compressor or machine that requires continuous lubrication.

[0052] Notably, linear compressor 100 is commonly filled with a predetermined volume of lubricant 204, e.g., based on the lubrication needs and pump positioning of the linear compressor 100. It may be desirable to ensure that pump inlet 208 remains submerged in lubricant 204 throughout operation of linear compressor 100, e.g., to prevent unlubricated compressor operation and potential compressor damage, noise, etc. Accordingly, housing 102 may generally define a lubricant fill line 212 to which lubricant 204 is added to ensure proper, safe operation of linear compressor 100. According to exemplary embodiments, pump inlet 208 is positioned below lubricant fill line 212, e.g., such that pump inlet 208 is submerged by at least 1 mm, at least 3 mm, at least 5 mm, at least 10 mm, or greater.

[0053] As shown, housing 102 generally defines a sump 202 which is configured for collecting oil (e.g., as identified herein by reference numeral 204, see FIG. 8). Specifically, sump 202 is defined in the bottom portion of lower housing 104. Lubrication system 200 further includes a pump 206 for continuously circulating oil 204 through components of linear compressor 100 which need lubrication. In this regard, for example, pump 206 may include a pump inlet 208 positioned proximate bottom of housing 102 within sump 202. Pump 206 may draw in oil 204 from sump 202 through pump inlet 208 before circulating it throughout linear compressor 100, e.g., via a supply conduit 210. Although only one supply conduit 210 is shown in the figures for clarity, it should be appreciated that lubrication system 200 may include any suitable number of supply conduits, nozzles, and other distribution features in order to provide oil 204 to various components throughout linear compressor 100.

[0054] Notably, according to the illustrated embodiment, pump inlet 208 is positioned very near and faces the bottom of lower housing 104. In this manner, pump 206 may readily draw in oil 204 even when oil levels are low. Specifically, linear compressor 100 may be configured for receiving oil 204 not to exceed a max oil fill line 212. For example, the max oil fill line 212 is identified in FIGS. 6-8, and may for example extend less than half the way up lower housing 104, less than a quarter of the way up lower housing 104, or lower. During operation, pump 206 may circulate oil 204 throughout linear compressor 100, after which the oil 204 will seep or flow out of the working components and collect in sump 202 before being recirculated. Although not illustrated here, it should be appreciated that lubrication system 200 may include various features for treating, filtering, or conditioning oil 204 during recirculation, such as various filters, screens, etc. In addition, it should be appreciated that although pump 206 is illustrated as being positioned within sump 202, it could be positioned at any other location and may include a fluid passage that draws oil 204 from sump 202.

[0055] As also illustrated in the figures, linear compressor 100 may include a suction inlet 220 for receiving a flow of refrigerant. Specifically, suction inlet 220 may be defined on housing 102 (e.g., such as on lower housing 104), and may be configured for receiving a refrigerant supply conduit to provide refrigerant to cavity 108. As explained above, flex mount 160 includes tubular wall 190, which defines channel 192 for directing compressible fluid, such as refrigerant gas, through flex mount 160 towards piston head 132. In this manner, desirable flow path of refrigerant gas is through suction inlet 220, through channel 192, through opening 196, and into chamber 118. Suction valve 128 may block opening 196 during a compression stroke and a discharge valve 116 may permit the compressed gas to exit chamber 118 when the desired pressure is reached.

[0056] Flex mount 160 may further define a channel inlet 230 which is positioned proximate a second end portion 174 of flex mount 160 for drawing gas and from suction inlet 220 or cavity 108 into channel 192. Specifically, channel inlet 230 may be an opening on flex mount 160 which extends substantially within a vertical plane and opens toward suction inlet 220. Specifically, according to the illustrated embodiment, channel inlet 230 and suction inlet 220 may be positioned substantially within the same horizontal plane. According to the illustrated embodiment, suction inlet 220 and channel inlet 230 are also positioned proximate a midpoint of housing 102 along a vertical direction V. However, it should be appreciated that according to alternative embodiments, suction inlet 220 and channel inlet 230 may be positioned at any other suitable locations within housing 102.

[0057] As mentioned above, it may be desirable to ensure that pump inlet 208 remains submerged in lubricant 204 throughout operation of linear compressor 100. In some instances, it may be difficult to maintain submersion of the pump inlet 208 within the lubricant 204. For example, if the compressor is tipped over or out of level, the oil 204 may slosh or otherwise flow away from the pump inlet 208. Such tipping may occur, for example, when the compressor is incorporated into a refrigerator appliance or other appliance in a recreational vehicle (RV) and during driving the RV on steep slopes. As another example, the compressor may be incorporated into an appliance which is installed out of level, such as on a sloped floor or other substrate.

[0058] In various examples, the out of level condition of the compressor may be a transient condition or a persistent condition, where a persistent out of level condition may include the lubricant flowing away from the pump inlet in a single linear and / or angular direction, and a transient out of level condition may include the lubricant sloshing back and forth in multiple directions relative to the pump inlet. For example, in an appliance in an RV, a persistent out of level condition may occur when driving on a steady and steep slope, where the compressor may be out of level in a single orientation (e.g., linear and / or angular) from the level position and the compressor may maintain such position for an extended period of time, such as at least about one second, such as at least about five seconds, such as at least about ten seconds. The single orientation as used herein includes the compressor in the same orientation (e.g., the same direction, although the distance from level may vary) away from the level position. In another example, continuing with reference to a compressor for an appliance in an RV, a transient out of level condition may occur, e.g., when driving over rough uneven roads or other surfaces, such that the compressor deviates from level in two or more different linear and / or angular directions within a relatively short time frame, such as maintaining any one direction from level for about ten seconds or less, such as about five seconds or less, such as about one second or less. For example, a transient out of level condition may include the compressor out of level in a first direction (such as a clockwise angle or above level along a linear axis) followed by returning to level and / or moving out of level in a second direction different from the first direction (such as a counterclockwise angle or below level along the linear axis).

[0059] FIG. 9 provides a schematic illustration of an exemplary compressor 100, e.g., the linear compressor described above or another suitable compressor (which may be, for example, a rotary compressor or a reciprocating compressor among other possible variations). As mentioned above, the compressor 100 may include a controller 250. Further, the controller 250 may be in communication with a measurement device 280 via one or more signal lines or shared communication busses. Optionally, measurement device 280 may be included with (e.g., integrated on-board) the controller 250. Moreover, measurement devices 280 may include a microprocessor that performs the calculations specific to the measurement of motion, position, and / or orientation with the calculation results being used by controller 250.

[0060] As illustrated in FIG. 9, one or more measurement devices 280 may be provided in or on the compressor 100, such as the compressor 100 may include an electrical box 260 mounted to the casing 102, and the electrical box 260 may house one or both of the controller 250 and the measurement device 280. The measurement device(s) 280 may be operable for measuring movement of the compressor 100, such as movement of the compressor 100 as a whole, such as shifting or tipping away from a level condition, and / or position or orientation of the compressor 100, such as a non-level position. Measurement devices 280 may measure a variety of suitable variables that can be correlated to movement and / or position of the compressor 100. The measurements obtained by such devices 280 can be utilized to monitor the level or balance state of the compressor 100 (e.g., to ensure that the compressor 100 does not tip over such that the pump inlet 208 is no longer submerged, and / or to detect such condition and take remedial actions in response).

[0061] A measurement device 280 in accordance with the present disclosure may include an accelerometer which measures translational motion, such as acceleration along one or more directions. Additionally or alternatively, a measurement device 280 may include a gyroscope, which measures rotational motion, such as rotational velocity about an axis. Additionally or alternatively, a measurement device 280 may include a magnetometer, which is responsive to geomagnetic fields. For example, the magnetometer may be used to measure a strength of the geomagnetic fields, e.g., a geomagnetic flux, and, based on the strength of the geomagnetic fields and / or changes therein, determine or estimate an orientation relative to the pull of gravity and / or changes in such orientation. In particular, a measurement device 280 may include all three (e.g., at least one of each) of an accelerometer, a gyroscope, and a magnetometer. A measurement device 280 in accordance with the present disclosure is mounted to the casing 102 (e.g., on an outer surface of the casing 102, such as in the electrical box 260 thereon) to sense movement and / or position of the compressor 100. For instance, movement may be measured as discrete identifiable components (e.g., in a predetermined direction) within a coordinate system defined by an X-axis, a Y-axis, and a Z-axis, where the X-axis, Y-axis, and Z-axis are each mutually perpendicular. For example, the Y-axis may be generally parallel to the axial direction A (FIGS. 3-5).

[0062] In exemplary embodiments, a measurement device 280 may include at least one gyroscope, at least one accelerometer, and / or at least one magnetometer. The measurement device 280, for example, may be a printed circuit board that includes the gyroscope, accelerometer, and magnetometer thereon. The measurement device 280 may be mounted to the casing 102 (e.g., via a suitable mechanical fastener, adhesive, etc.) and may be oriented such that the various sub-components (e.g., the gyroscope, accelerometer, and magnetometer) are oriented to measure movement along or about particular directions as discussed herein. Notably, the gyroscope, accelerometer, and magnetometer in exemplary embodiments are advantageously mounted to the casing 102 at a single location (e.g., the location of the printed circuit board or other component of the measurement device 280 on which the gyroscope, accelerometer, and magnetometer are grouped). Such positioning at a single location advantageously reduces the costs and complexity (e.g., due to additional wiring, etc.) of out-of-level detection, while still providing relatively accurate detection as discussed herein. Alternatively, however, the gyroscope and accelerometer need not be mounted at a single location. For example, a gyroscope located at one location on casing 102 can measure the rotation of an accelerometer located at a different location on casing 102, because rotation about a given axis is the same everywhere on a solid object such as casing 102.

[0063] In some embodiments, movement is measured as a plurality of unique displacement values. Optionally, the displacement values may occur in discrete channels of motion (e.g., as distinct directional components of movement). For instance, displacement values may correspond to one or more indirectly measured movement components perpendicular or approximately perpendicular to a center G (e.g., geometric center of gravity based on the shape and mass of the compressor 100) of the compressor 100. Such movement components may, for example, occur in a plane defined by the X-axis and the Z-axis (i.e., the X-Z plane) or in a plane perpendicular to the X-Y plane, e.g., a plane defined by the Y-axis and the Z-axis (i.e., the Y-Z plane). Movement of the compressor 100 along the particular direction may be calculated using the indirect measurement component and other suitable variables, such as an axial and / or radial offset distance along the vector from the measurement device 280 to the center G of the casing 102. Additionally or alternatively, the displacement values may correspond to one or more directly measured movement components. Such movement components may, for example, occur in the X-Z plane or in the Y-Z plane.

[0064] Notably, the term “approximately” as utilized with regard to the orientation and position of such movement measurements denotes ranges such as of plus or minus 2 inches or plus or minus 10 degrees relative to various axes passing through the center G of the compressor 100.

[0065] In some embodiments, an out-of-level condition may be determined, at least in part, from the measurements obtained by measurement device 280. For instance, controller 250 may correlate displacement (e.g., one or more linear and / or angular displacement) values to an out of level condition, such as when one or more displacements exceeds a threshold or tolerance limit. As mentioned above, the out of level condition may be persistent (e.g., linear and / or angular displacement exceeding the threshold in a single direction throughout a period of time) or transitory (e.g., multiple linear and / or angular displacements exceeding respective thresholds in different directions within the period of time).

[0066] Now that the descriptions of an exemplary compressor, as well as a sealed system and appliance into which the compressor may be incorporated, have been provided, a method 300 of operating a compressor, such as but not limited to compressor 100, will be described. Although the discussion below refers to the exemplary method 300 of operating compressor 100, one skilled in the art will appreciate that the exemplary method 300 is applicable to any suitable compressor, and that such compressors may be incorporated into a variety of domestic appliances or household appliances, e.g., a refrigerator appliance, an air conditioner appliance, a clothes dryer appliance, and other such appliances. In exemplary embodiments, the various method steps as disclosed herein may be performed by controller 250 and / or a separate, dedicated controller. FIG. 10 provides a flow chart illustrating a method of operating a compressor. Hereinafter, method 300 will be described with specific reference to FIG. 10.

[0067] As noted above, method 300 may be practiced with any suitable compressor, such as the exemplary compressor 100 described above. More particularly, the compressor may include a housing defining a sump for collecting lubricant and a pump for circulating the lubricant within the housing. The pump may include a lubricant intake tube defining a pump inlet positioned within the sump. The compressor may further include a measurement device.

[0068] As illustrated in FIG. 10, method 300 may include (310) operating the compressor to increase the pressure and temperature of a refrigerant. Method 300 may further include (320) detecting, with the measurement device, a position of the compressor while operating the compressor. For example, the position of the compressor may be determined with reference to a certain predefined angle (e.g., with respect to a horizontal plane, such as the X-Y plane, e.g., as indicated in FIG. 9). When the measurement device determines that the compressor is at or past the predefined angle, the oil pump (e.g., the inlet thereof) can be determined to be out of the oil (e.g., at least partially above a level of the oil or lubricant) and therefore not supplying lubrication to the moving compressor parts. The predefined angle may be defined in any suitable plane, such as the X-Z plane or the Y-Z plane as described above, and / or relative to a horizontal direction or horizontal plane. In some embodiments, multiple predefined limit angles may be defined in various planes, and the compressor may be shut down in response to detecting a position of the compressor (e.g., with the measurement device) that is at or above any one or more of the multiple predefined limit angles (such angles being defined in diverse planes). The position of the compressor may also or instead be determined with reference to a predetermined degree of rotation, such as rotation about the X-axis or the Y-axis, the axial direction A, and / or one or more other axes of rotation which are generally perpendicular to the vertical direction V (e.g., FIGS. 1 and 3) and / or the Z-axis (e.g., FIG. 9). Further, the position of the compressor may also or instead be determined with reference to geomagnetic fields, e.g., using the magnetometer to determine an orientation of the compressor relative to the pull of Earth's gravity.

[0069] Accordingly, the controller may be configured for, and / or method 300 may include, shutting down the compressor operation in response to the detected position of the compressor, as indicated at (330) in FIG. 10, e.g., deactivating the compressor when it gets past the predefined angle, degree of rotation, and / or geomagnetic orientation. In various embodiments, the controller may be configured for, and / or the method 300 may include, shutting the compressor down until the oil level is acceptable (e.g., as determined based on the position of the compressor, e.g., returning below the predetermined limit angle, degree of rotation and / or geomagnetic flux, and which may also include a settling time after returning to a generally level position to allow the lubricant to fully flow back down into the sump). The controller may also be configured for, and / or the method 300 may also include, shutting the compressor down until there is a call for heating or colling, such as when temperatures in the refrigerator (in example embodiments where the compressor is coupled to a sealed system of a refrigerator appliance) gets unacceptably high.

[0070] For example, in some embodiments, the detected position in response to which the compressor is deactivated may be an out-of-level position, e.g., a persistent or transitory out-of-level position, as described above. When the compressor is in the out-of-level position, the pump inlet may be at least partially above a lubricant level within the sump, such as a center of the pump inlet may be above the lubricant level, or such as the pump inlet may be fully above the lubricant level where the entire pump inlet is outside of the lubricant. For example, the lubricant level may be a maximum lubricant level or a top of a volume of lubricant, e.g., at or approximately at the fill line 212 (see, e.g., FIGS. 6-8).

[0071] In some embodiments, the compressor may be reactivated when the compressor returns to a level position, or at least within a tolerance range of the level position, e.g., at an angle, degree of rotation, and / or geomagnetic flux less than the predefined limit(s) mentioned above. For example, methods according to the present subject matter, such as method 300, may further include (where the detected position of the compressor is a first detected position) detecting, with the measurement device, a second position of the compressor after the first detected position. Such embodiments may further include reactivating the compressor in response to the second detected position of the compressor. In such embodiments, the first detected position of the compressor may be an out-of-level position (e.g., at or above the predefined limit in one direction (e.g., a persistent out-of-level) or in multiple different directions (e.g., a transitory out-of-level)) and the second detected position of the compressor may be a level position (e.g., below the predefined limit).

[0072] In some embodiments, the compressor may be reactivated in response to a call for heating or cooling, e.g., when the compressor is coupled to a sealed system such as the exemplary sealed system illustrated in FIG. 2 (and even if the compressor has not yet returned to a level position). For example, in embodiments where the sealed system is incorporated into a refrigerator appliance, preserving food within the chilled chamber(s) of the refrigerator appliance may take precedence over the oil level, e.g., when the temperature in the chilled chamber(s) exceeds a predefined safety factor or threshold away from (e.g., above, in this example) a target temperature, e.g., to prevent food spoiling and / or to maintain a temperature within a food storage compartment at or below a maximum safe temperature. Thus, in some embodiments, e.g., the controller may be configured for, and / or the method may include, reactivating the compressor in response to a call for cooling. In such embodiments, the compressor may be coupled to a sealed system of a refrigerator appliance, and the call for cooling may be based on a set temperature of a chilled chamber of the refrigerator appliance.

[0073] The written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Examples

Embodiment Construction

[0022]Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0023]As used herein, terms of approximation, such as “generally,” or “about” include values within ten percent greater or less than the stated value. When used in the context of an angle or direction, such terms include within ten degrees greater or less t...

Claims

1. A compressor, the compressor comprising:a housing defining a sump for collecting lubricant;a pump for circulating the lubricant within the housing, the pump comprising a lubricant intake tube defining a pump inlet positioned within the sump;a measurement device; anda controller in operative communication with the measurement device, the controller configured for:operating the compressor to increase pressure and temperature of a refrigerant;detecting, with the measurement device, a position of the compressor while operating the compressor; anddeactivating the compressor in response to the detected position of the compressor.

2. The compressor of claim 1, wherein the detected position of the compressor is an out-of-level position.

3. The compressor of claim 2, wherein the pump inlet is at least partially above a lubricant level within the sump when the compressor is in the out-of-level position.

4. The compressor of claim 1, wherein the detected position of the compressor is a first detected position, wherein the controller is further configured for detecting, with the measurement device, a second position of the compressor after the first detected position, and reactivating the compressor in response to the second detected position of the compressor.

5. The compressor of claim 4, wherein the first detected position of the compressor is an out-of-level position and the second detected position of the compressor is a level position.

6. The compressor of claim 5, wherein the pump inlet is at least partially above a lubricant level within the sump when the compressor is in the out-of-level position.

7. The compressor of claim 1, wherein the controller is further configured for reactivating the compressor in response to a call for cooling.

8. The compressor of claim 7, wherein the compressor is coupled to a sealed system of a refrigerator appliance, and wherein the call for cooling is based on a set temperature of a chilled chamber of the refrigerator appliance.

9. The compressor of claim 1, wherein the measurement device comprises at least one of an accelerometer, a gyroscope, and a magnetometer.

10. A method of operating a compressor, the compressor comprising a housing defining a sump for collecting lubricant, a pump for circulating the lubricant within the housing, the pump comprising a lubricant intake tube defining a pump inlet positioned within the sump, and a measurement device, the method comprising:operating the compressor to increase pressure and temperature of a refrigerant;detecting, with the measurement device, a position of the compressor while operating the compressor; anddeactivating the compressor in response to the detected position of the compressor.

11. The method of claim 10, wherein the detected position of the compressor is an out-of-level position.

12. The method of claim 11, wherein the pump inlet is at least partially above a lubricant level within the sump when the compressor is in the out-of-level position.

13. The method of claim 10, wherein the detected position of the compressor is a first detected position, the method further comprising detecting, with the measurement device, a second position of the compressor after the first detected position, and reactivating the compressor in response to the second detected position of the compressor.

14. The method of claim 13, wherein the first detected position of the compressor is an out-of-level position and the second detected position of the compressor is a level position.

15. The method of claim 14, wherein the pump inlet is at least partially above a lubricant level within the sump when the compressor is in the out-of-level position.

16. The method of claim 10, further comprising reactivating the compressor in response to a call for cooling.

17. The method of claim 16, wherein the compressor is coupled to a sealed system of a refrigerator appliance, and wherein the call for cooling is based on a set temperature of a chilled chamber of the refrigerator appliance.

18. The method of claim 10, wherein the measurement device comprises at least one of an accelerometer, a gyroscope, and a magnetometer.

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