Compressor

Abstract: A compressor includes a sealed casing (2) which accommodates therein a compressing unit (6) for compressing a refrigerant and a driving unit (7) for driving the compressing unit. An induction pipe (18) is provided in the sealed casing for introducing the refrigerant into the compressing unit. The induction pipe has an outlet end communicating with the interior of the compressing unit and an inlet end which is opened to space in the sealed casing at a position which may correspond to a node of a standing wave of the refrigerant in the sealed casing.

Description: The present invention relates generally to a compressor or a closed-type compressor for use in, such as, a refrigerator. Recently, hermetic compressors with reduced noise have been largely demanded in view of the environmental amenity. In order to satisfy such demands, there has been proposed a hermetic compressor having a hermetic or sealed casing of such a shape as to prevent generation of a resonance sound in the sealed casing, as disclosed such as in Japanese Second (examined) Patent Publication No. 3-53476, which corresponds to US-A-4 729 723 and on which the preamble of claim 1 is based. Specifically, the proposed conventional sealed casing has a shape such that a straight line drawn from any portion of its inner wall at a right angle intersects with an opposite portion of the inner wall at an angle other than the right angle. This structure serves to prevent generation of resonance in the sealed casing since an acoustic or sound wave reflected by the opposite inner wall portion does not return to the portion where it comes from. Accordingly, this structure serves to prevent increment of the noise which would be otherwise caused by the resonance in the sealed casing, so as to provide the hermetic compressor with reduced noise. However, the foregoing conventional structure has the following drawbacks: Specifically, according to the conventional structure, as an angle between the above-noted straight line and the opposite inner wall portion deviates from the right angle by a larger degree, the effect for preventing the generation of resonance in the sealed casing becomes larger. However, in order to provide a larger deviation from the right angle for enhancing such an effect, a shape of the sealed casing has to be distorted unnaturally. As a result, the sealed casing is weakened in strength, which causes increment of the noise caused by vibration of the sealed casing. In addition, since the shape of the sealed casing is forced to be distorted in view of reducing the resonance noise, the space in the sealed casing can not be effectively utilized in comparison with a sealed casing having a normal shape. As a result, the sealed casing undesirably increases in size for accommodating therein a compressing unit and a driving unit which drives the compressing unit. The present invention aims to provide an improved hermetic compressor with reduced noise that can eliminate the foregoing disadvantages inherent in the conventional hermetic compressors. According to the present invention, there is provided a compressor comprising: a sealed casing having in its normal orientation a horizontal cross-section which is non-circular; compressing means provided in said sealed casing, for compressing a refrigerant; driving means, provided in said sealed casing, for driving said compressing means; and induction means for introducing the refrigerant into said compressing means, said induction means having a first end communicating with said compressing means and a second end which is opened to space in said sealed casing, characterised in that said second end is open to space in said sealed casing at a position substantially corresponding to a node of a standing wave of the refrigerant in said sealed casing, which standing wave is generated due to operation of said compressing means via said induction means. The second end of the induction means may open to space in said sealed casing at a position on a plane A which is normal to, and bisects, the diameter of minimum length extending between points on an internal wall of said casing at the level of, and through, the centre of gravity of the horizontal interior section of maximum area, when the compressor is in its normal orientation. The second end of induction means may open to space in said sealed casing at a position on a plane B which is normal to, and bisects, the line segment of maximum length in the horizontal interior section of maximum area extending between points on an internal wall of said casing perpendicular to the diameter of minimum length extending between points on an internal wall of said casing at a level of, and through, the centre of gravity of said horizontal interior section, when the compressor is in its normal orientation. The compressor may contain lubricant at its lower part and the second end of the induction means may open to space in said sealed casing at a position on a plane C which is normal to, and bisects, the vertical line segment of maximum length between an upper point on an internal wall of said casing and a level of said lubricant in said casing, when the compressor is in its normal orientation. Preferably the compressor may be hermetically sealed or a hermetic compressor. The present invention will be understood more fully from the detailed description given hereinbelow and from the accompanying drawings of the preferred embodiments of the invention, which are given by way of example only, and are not intended to be limitative of the present invention. In the drawings : Fig. 1 is a schematic vertical sectional view of a hermetic compressor according to a first preferred embodiment of the present invention; Fig. 2 is a schematic horizontal sectional view of the hermetic compressor according to the first preferred embodiment, wherein components in a sealed casing are illustrated in top plan view; Fig. 3 is a schematic horizontal sectional view of a hermetic compressor according to a first modification of the first preferred embodiment, wherein components in a sealed casing are illustrated in a top plan view; Fig. 4 is a schematic vertical sectional view of a hermetic compressor according to a second modification of the first preferred embodiment; Fig. 5 is a schematic vertical sectional view of a hermetic compressor according to a second preferred embodiment of the present invention; Fig. 6 is a schematic horizontal sectional view of the hermetic compressor according to the second preferred embodiment, wherein components in a sealed casing are illustrated in a top plan view; Fig. 7 is a schematic vertical sectional view of a hermetic compressor according to a first modification of the second preferred embodiment; Fig. 8 is a schematic horizontal sectional view of the hermetic compressor according to the first modification of the second preferred embodiment, wherein components in a sealed casing are illustrated in a top plan view; Fig. 9 is a schematic vertical sectional view of a hermetic compressor according to a second modification of the second preferred embodiment; and Fig. 10 is a schematic horizontal sectional view of the hermetic compressor according to the second modification of the second preferred embodiment, wherein components in a sealed casing are illustrated in a top plan view. Figs. 1 and 2 respectively show a hermetic compressor 1 according to a first preferred embodiment of the present invention, wherein Fig. 1 is a longitudinal or vertical sectional view of the hermetic compressor 1, and Fig. 2 is a cross-sectional or horizontal sectional view of the hermetic compressor 1 with components in a hermetic or sealed casing 2 being illustrated in a top plan view. As shown in Fig. 1, the sealed casing 2 is formed by a lower casing member 3 and an upper casing member 4 which are firmly fixed to each other. As shown in Fig. 2. the interior or the interior space of the sealed casing 2 has an oval shape or a substantially elliptic shape in horizontal section. In Figs. 1 and 2, numeral 5 designates a driving-compressing unit which is resiliently supported by coil springs 8. The driving-compressing unit 5 includes a compressing unit 6 and a driving unit 7. The compressing unit 6 includes, such as, a cylinder 10 formed integral with a base block 9, a piston 11, a crankshaft 12, a connecting rod 13 and a bearing 14. The driving unit 7 includes a rotor 15 and a stator 16 to form a motor. The rotor 15 is fixed to the crankshaft 12 by shrinkage fitting, and the stator 16 is fixed to the base block 9 by screws. Numeral 17 represents lubricating oil stored in the sealed casing 2 at its lower part. Letter A (Fig. 2) represents a minimum horizontal distance among horizontal distances each measured between arbitrary two opposite points on an internal wall of the sealed casing 2 at a level of a certain horizontal section of the interior of the sealed casing 2, via a center of gravity of such a horizontal section. Specifically. this horizontal section is selected so as to have a maximum area over the height or the vertical length of the sealed casing 2, i.e. an area of this horizontal section being maximum among areas of horizontal sections of the interior of the sealed casing 2 over the vertical length of the sealed casing 2. As appreciated, the interior of the sealed casing 2 is defined by the above-noted internal wall of the sealed casing 2. In other words, A represents a minimum length among lengths of line segments each extending between arbitrary two opposite points on the internal wall of the sealed casing 2 at the level of the above-noted horizontal section via the center of gravity thereof. Alternatively, it may be also defined that A represents a maximum distance among distances each measured between arbitrary two opposite points on the internal wall of the sealed casing 2 in a direction perpendicular to directions of the reciprocating motion of the piston 11 as well as to an axial direction of the crankshaft 12. Letter B represents a maximum horizontal distance among horizontal distances each between arbitrary two opposite points on the internal wall of the sealed casing 2, as measured in a direction perpendicular to the line segment having the above-noted minimum length A (hereinafter referred to as "minimum length line segment A") on a horizontal plane including this minimum length line segment A, i.e. at the level of the above-noted certain horizontal section of the interior of the sealed casing 2. In other words, B represents a maximum length among lengths of line segments each extending between arbitrary two opposite points on the internal wall of the sealed casing 2. as measured in a direction perpendicular to the minimum length line segment A on a horizontal plane including this minimum length line segment A, i.e. at the level of the above-noted certain horizontal section of the interior of the sealed casing 2. Alternatively, it may be also defined that B represents a maximum distance among distances each between arbitrary two opposite points on the internal wall of the sealed casing 2, as measured in the directions of the reciprocating motion of the piston 11. Letter C represents a maximum vertical distance among vertical distances each measured between an arbitrary upper point on the internal wall of the sealed casing 2 and an oil level of the lubricating oil 17 in the sealed casing 2. In other words, C represents a maximum length among lengths of line segments each extending between an arbitrary upper point on the internal wall of the sealed casing 2 and an oil level of the lubricating oil 17 in the sealed casing 2. In this preferred embodiment, the following dimensions are set for the distances or lengths A, B and C: A = 138 mm, B = 145 mm, C = 160 mm Numeral 18 designates a suction or induction pipe which is fixed to the base block 9 and communicates with the interior of the cylinder 10 at its one end working as an outlet. The suction pipe 18 has the other end, working as an inlet, which is opened to space or room in the sealed casing 2 at a position on a certain plane. This plane intersects with the minimum length line segment A at a middle point thereof and in perpendicular thereto, as clearly shown in Fig. 2. Now, operations of the hermetic compressor 1 as structured above according to the first preferred embodiment will be described hereinbelow. A refrigerant which has been circulated through a refrigeration system of, such as, the refrigerator is introduced to the interior of the sealed casing 2 in a known manner. The introduced refrigerant is then sucked into the cylinder 10 via the suction pipe 18 and pressurized or compressed due to the reciprocating motion of the piston 11. Specifically, the refrigerant is sucked into the cylinder 10 during a half (1/2) rotation of the crankshaft 12, and is pressurized during a subsequent half (1/2) rotation of the crankshaft 12. Accordingly, since the refrigerant is not sucked into the cylinder 10 in a continuous manner, pressure pulsation of the refrigerant is generated at the suction pipe 18. This pressure pulsation excites the space to cause vibration in the sealed casing 2 so that the compressor 1 has possible resonance modes in directions of the reciprocating motion of the piston 11 and in directions perpendicular to the directions of the reciprocating motion of the piston 11, wherein each of "resonance modes" represents a state of the compressor 1 corresponding to one of the possible resonance frequencies of the compressor 1. In this preferred embodiment, it has been confirmed through experiments and analyses that a resonance frequency of the resonance mode of the compressor 1 in the direction of the minimum length line segment A (hereinafter referred to as "direction A") becomes 585Hz which corresponds to a frequency of a pressure pulsation component of the refrigerant (HFC-134a) in the direction A, i.e. a frequency of a standing wave of the refrigerant in the direction A. The frequency of 585Hz is an integral multiple of a rotational frequency of the driving unit 7 as operated at 50Hz. As a result, the resonance mode of the compressor 1 in the direction A is satisfied or established. However, as described above, the suction pipe 18 has the open end or opening at the position on the plane which intersects with the minimum length line segment A at its middle point and in perpendicular thereto. This means that the suction pipe 18 is opened at a position corresponding to a node of the standing wave in the direction A, i.e. at a position on a vertical plane defined by the node of the standing wave in the direction A. Accordingly. the pressure pulsation component of the refrigerant applies vibration at the node of the standing wave in the direction A so that the generation of the resonance is effectively suppressed. Various experiments have shown that a sound of 585Hz representing the resonance sound is reduced by more than 10dB by positioning the opening of the suction pipe 18 as described above. This means that increment of the noise of the compressor 1, which would be otherwise caused due to the resonance sound, is effectively prevented in the first preferred embodiment. Fig. 3 is a horizontal sectional view of the hermetic compressor 1, as corresponding to Fig. 2, according to a first modification of the first preferred embodiment. In Fig. 3, the same or corresponding elements and dimensions are designated by the same references as those in Figs. 1 and 2 so as to avoid redundant disclosure. In the first modification of Fig. 3, the dimensional relationship among the distances or lengths A, B and C is set such that the resonance mode of the compressor 1 is satisfied or activated in a direction of the line segment having the maximum length B (hereinafter referred to as "direction B"). In Fig. 3, the suction pipe 18 has one end communicating with the interior of the cylinder 10 as in the first preferred embodiment, and the other end being opened at a position on a plane which intersects with the line segment having the maximum length B (hereinafter referred to as "maximum length line segment B") at its middle point and in perpendicular thereto, or which intersects with any one of the line segments at its middle point and in perpendicular thereto, those line segments each extending between arbitrary two opposite points on the internal wall of the sealed casing 2 and in perpendicular to the minimum length line segment A on the horizontal plane. This means that the suction pipe 18 is opened at a position corresponding to a node of a standing wave in the direction B, i.e. at a position on a vertical plane defined by the node of the standing wave in the direction B. The first modification effectively works to suppress the generation of the resonance sound when the resonance mode of the compressor 1 in the direction B is satisfied, for the reason as described in the first preferred embodiment. The other structure of the first modification is substantially the same as that in the first preferred embodiment. Fig. 4 is a vertical sectional view of the hermetic compressor 1, as corresponding to Fig. 1, according to a second modification of the first preferred embodiment. In Fig. 4, the same or corresponding elements and dimensions are designated by the same references as those in Figs. 1 and 2 so as to avoid redundant disclosure. In the second modification of Fig. 4, the dimensional relationship among the distances or lengths A, B and C is set such that the resonance mode of the compressor 1 is satisfied in a direction of the line segment having the maximum length C (hereinafter referred to as "direction C"). In Fig. 4, the suction pipe 18 has one end communicating with the interior of the cylinder 10 as in the first preferred embodiment, and the other end being opened at a position on a plane which intersects with the line segment having the maximum length C (hereinafter referred to as "maximum length line segment C") at its middle point and in perpendicular thereto. This means that the suction pipe 18 is opened at a position corresponding to a node of a standing wave in the direction C, i.e. at a position on a horizontal plane defined by the node of the standing wave in the direction C. The second modification effectively works to suppress the generation of the resonance sound when the resonance mode of the compressor 1 in the direction C is satisfied, for the reason as described in the first preferred embodiment. The other structure of the second modification is substantially the same as that in the first preferred embodiment. Now, a second preferred embodiment will be described with reference to Figs. 5 and 6, wherein Fig. 5 is a vertical sectional view of the compressor 1, as corresponding to Fig. 1, and Fig. 6 is a horizontal sectional view of the compressor 1, as corresponding to Fig. 2. In Figs. 5 and 6, the same or corresponding elements and dimensions are designated by the same references as those in Figs. 1 and 2 so as to avoid redundant disclosure. In the second preferred embodiment of Figs. 5 and 6, the dimensional relationship among the distances or lengths A, B and C is set as follows: A = 138 mm, B = 145 mm, C = 150 mm In Figs. 5 and 6, the suction pipe 18 has one end communicating with the interior of the cylinder 10 as in the first preferred embodiment. On the other hand, the suction pipe 18 has the other end being opened at a position on a line of intersection between a plane which intersects with the minimum length line segment A at its middle point and in perpendicular thereto and a plane which intersects with the maximum length line segment C at its middle point and in perpendicular thereto. This means that the suction pipe 18 is opened at a position corresponding to a node of a standing wave in the direction A, i.e. at a position on a vertical plane defined by the node of the standing wave in the direction A, and simultaneously, at a position corresponding to a node of a standing wave in the direction C, i.e. at a position on a horizontal plane defined by the node of the standing wave in the direction C. In this preferred embodiment, it has been confirmed through experiments and analyses that a resonance frequency of the resonance mode of the compressor 1 in the direction A becomes 585Hz which corresponds to a frequency of a pressure pulsation component of the refrigerant (HFC-134a) in the direction A, i.e. a frequency of a standing wave in the direction A. The frequency of 585Hz is an integral multiple of a rotational frequency of the driving unit 7 as operated at 50Hz. As a result, the resonance mode of the compressor 1 in the direction A is satisfied. It has further been confirmed that a resonance frequency of the resonance mode of the compressor 1 in the direction C becomes 535Hz which corresponds to a frequency of a pressure pulsation component of the refrigerant (HFC-134a) in the direction C, i.e. a frequency of a standing wave in the direction C. The frequency of 535Hz is an integral multiple of the rotational frequency of the driving unit 7 as operated at 50Hz. As a result, the resonance mode of the compressor 1 in the direction C is also satisfied. However, as described above, in the second preferred embodiment, the suction pipe 18 is opened at the position on the above-noted intersecting line formed by the intersection between the above-noted two planes. Accordingly, the pressure pulsation components of the refrigerant apply vibration at the nodes of the standing waves for both the resonance mode in the direction A and the resonance mode in the direction C so that the generation of the resonance sound is effectively suppressed. As a result, increment of the noise of the compressor 1, which would be otherwise caused due to the resonance sound, is effectively prevented in the second preferred embodiment even when the resonance modes of the compressor 1 in the directions both A and C are satisfied. The other structure of the second preferred embodiment is substantially the same as that in the first preferred embodiment. Figs. 7 and 8 show a first modification of the second preferred embodiment, and correspond to Figs. 5 and 6 of the second preferred embodiment, respectively. In Figs. 7 and 8, the same or corresponding elements and dimensions are designated by the same references as those in Figs. 5 and 6 so as to avoid redundant disclosure. In the first modification of Figs. 7 and 8, the dimensional relationship among the distances or lengths A, B and C is set such that the resonance modes of the compressor 1 are satisfied in the directions B and C. In Figs. 7 and 8, the suction pipe 18 has one end communicating with the interior of the cylinder 10 as in the second preferred embodiment. On the other hand, the suction pipe 18 has the other end being opened at a position on a line of intersection between a plane which intersects with the maximum length line segment B at its middle point and in perpendicular thereto or which intersects with any one of the line segments at its middle point and in perpendicular thereto, those line segments each extending between arbitrary two opposite points on the internal wall of the sealed casing 2 and in perpendicular to the minimum length line segment A on the horizontal plane, and a plane which intersects with the maximum length line segment C at its middle point and in perpendicular thereto. This means that the suction pipe 18 is opened at a position corresponding to a node of a standing wave in the direction B, i.e. at a position on a vertical plane defined by the node of the standing wave in the direction B, and simultaneously, at a position corresponding to a node of a standing wave in the direction C, i.e. at a position on a horizontal plane defined by the node of the standing wave in the direction C. The first modification of the second preferred embodiment effectively works to suppress the generation of the resonance sound when the resonance modes of the compressor 1 in the directions both B and C are satisfied, for the reason as described in the second preferred embodiment. The other structure of the first modification is substantially the same as that in the second preferred embodiment. Figs. 9 and 10 show a second modification of the second preferred embodiment, and correspond to Figs. 5 and 6 of the second preferred embodiment, respectively. In Figs. 9 and 10, the same or corresponding elements and dimensions are designated by the same references as those in Figs. 5 and 6 so as to avoid redundant disclosure. In the second modification of Figs. 9 and 10, the dimensional relationship among the distances or lengths A, B and C is set such that the resonance modes of the compressor 1 are satisfied in the directions A and B. In Figs. 9 and 10, the suction pipe 18 has one end communicating with the interior of the cylinder 10 as in the second preferred embodiment. On the other hand, the suction pipe 18 has the other end being opened at a position on a line of intersection between a plane which intersects with the minimum length line segment A at its middle point and in perpendicular thereto and a plane which intersects with the maximum length line segment B at its middle point and in perpendicular thereto or which intersects with any one of the line segments at its middle point and in perpendicular thereto, those line segments each extending between arbitrary two opposite points on the internal wall of the sealed casing 2 and in perpendicular to the minimum length line segment A on the horizontal plane. This means that the suction pipe 18 is opened at a position corresponding to a node of a standing wave in the direction A, i.e. at a position on a vertical plane defined by the node of the standing wave in the direction A, and simultaneously, at a position corresponding to a node of a standing wave in the direction B, i.e. at a position on a vertical plane defined by the node of the standing wave in the direction B. The second modification of the second preferred embodiment effectively works to suppress the generation of the resonance sound when the resonance modes of the compressor 1 in the directions both A and B are satisfied, for the reason as described in the second preferred embodiment. The other structure of the second modification is substantially the same as that in the second preferred embodiment. In a further modification of the second preferred embodiment, wherein the dimensional relationship among the distances or lengths A, B and C is set such that the resonance modes of the compressor 1 are satisfied in the directions A, B and C, the following structure may be arranged: Specifically, the suction pipe 18 has one end communicating with the interior of the cylinder 10 as in the second preferred embodiment. On the other hand, the suction pipe 18 has the other end being opened at a point of intersection among a plane which intersects with the minimum length line segment A at its middle point and in perpendicular thereto, a plane which intersects with the maximum length line segment B at its middle point and in perpendicular thereto or which intersects with any one of the line segments at its middle point and in perpendicular thereto, those line segments each extending between arbitrary two opposite points on the internal wall of the sealed casing 2 and in perpendicular to the minimum length line segment A on the horizontal plane, and a plane which intersects with the maximum length line segment C at its middle point and in perpendicular thereto. This means that the suction pipe 18 is opened at a position corresponding to a node of a standing wave in the direction A, i.e. at a position on a vertical plane defined by the node of the standing wave in the direction A. and simultaneously, at a position corresponding to a node of a standing wave in the direction B, i.e. at a position on a vertical plane defined by the node of the standing wave in the direction B, and further simultaneously, at a position corresponding to a node of a standing wave in the direction C, i.e. at a position on a horizontal plane defined by the node of the standing wave in the direction C. This further modification of the second preferred embodiment effectively works to suppress the generation of the resonance sound when the resonance modes of the compressor 1 in the directions A, B and C are satisfied, for the reason as described in the second preferred embodiment. It is to be understood that this invention is not to be limited to the preferred embodiments and modifications described above, and that various changes and modifications may be made without departing from the scope of the invention as defined in the appended claims. For example, when a muffler or the like is additionally provided at the suction pipe 18, similar effects may be realized by positioning an open end of the muffler as described in the first and second preferred embodiments and their modifications. Further, in a direct-suction-type compressor, similar effects may be realized by positioning a coupling portion between a suction pipe and a muffler as described in the first and second preferred embodiments and their modifications. The coupling portion is provided in the sealed casing using, such as, a spring for connection with a refrigeration system of, such as, the refrigerator. Further, the present invention is applicable irrespective of a compression manner of the compressor or the number of the cylinders 10. Further, even when the suction pipes 18 are provided in number more than one, similar effects may be realized by arranging the opening of each suction pipe at the position on the foregoing plane or on the foregoing intersecting line or point.

Claims: A compressor comprising: a sealed casing (2) having in its normal orientation a horizontal cross-section which is non-circular; compressing means (6) provided in said sealed casing, for compressing a refrigerant; driving means (7), provided in said sealed casing, for driving said compressing means; and induction means (18) for introducing the refrigerant into said compressing means, said induction means having a first end communicating with said compressing means and a second end which is opened to space in said sealed casing, characterised in that said second end is open to space in said sealed casing at a position substantially corresponding to a node of a standing wave of the refrigerant in said sealed casing, which standing wave is generated due to operation of said compressing means via said induction means. A compressor according to claim 1, wherein said compressor has possible resonance modes in particular directions, and wherein said standing wave establishes one of said possible resonance modes of the compressor. A compressor as set forth in claim 2, wherein said position further corresponds to a node of a standing wave which establishes another resonance mode of the compressor. A compressor according to claim 1, 2 or 3, wherein said second end of said induction means (18) is open to space in said sealed casing at a position on a plane A which is normal to, and bisects, the diameter of minimum length extending between points on an internal wall of said casing at the level of, and through, the centre of gravity of the horizontal interior section of maximum area, when the compressor is in its normal orientation. A compressor according to claim 4, wherein said position is located on the line of intersection between said plane A and a plane B which is normal to, and bisects, the line segment of maximum length extending between points on an internal wall of said casing perpendicular to said diameter of minimum length and in the same horizontal plane, when the compressor is in its normal orientation. A compressor according to claim 4, containing lubricant at its lower part and wherein said position is located on a line of intersection between said plane A and a plane C which is normal to, and bisects, the vertical line segment of maximum length between an upper point on an internal wall of said casing and the normal a level of said lubricant in said casing, when the compressor is in its normal orientation. A compressor according to claim 1, 2 or 3, wherein said second end of said induction means (18) is open to space in said sealed casing at a position on a plane B which is normal to, and bisects, the line segment of maximum length in the horizontal interior section of maximum area extending between points on an internal wall of said casing perpendicular to the diameter of minimum length extending between points on an internal wall of said casing at a level of, and through, the centre of gravity of said horizontal interior section, when the compressor is in its normal orientation. The compressor as set forth on claim 7, contains lubricant at its lower part and wherein said position is located on a line of intersection between said plane B and a plane C which is normal to, and bisects, the vertical line segment of maximum length between an upper point on an internal wall of said casing and a level of said lubricant in said casing, when the compressor is in its normal orientation. A compressor according to claim 1, 2 or 3, containing lubricant at its lower part, wherein said second end of the induction means (18) is open to space in said sealed casing at a position on a plane C which is normal to, and bisects, the vertical line segment of maximum length between an upper point on an internal wall of said casing and a level of said lubricant in said casing, when the compressor is in its normal orientation. A refrigerator including a compressor according to any one of the preceding claims.

Inventors: AKASHI HIRONARI, INAGAKI KOH, KITA ICHIRO, KOYAMA TAKASHI, YABIKI JUNICHIRO, YOSHIMURA TAKAO, AKASHI, HIRONARI, INAGAKI, KOH, KITA, ICHIRO, KOYAMA, TAKASHI, YABIKI, JUNICHIRO, YOSHIMURA, TAKAO
Applicants: MATSUSHITA REFRIGERATION, MATSUSHITA REFRIGERATION COMPANY
Application year: 1993
Main classification: F04B39
IPC codes: F04B39