Compressor discharge muffler

Abstract: An electrically-operated sealed compressor includes a cylinder, a cylinder head mounted on the cylinder and having a suction chamber and first and second discharge chambers, a piston accommodated in the cylinder, and a valve mechanism. The valve mechanism includes a suction muffler and a valve plate having at least one suction port, first and second discharge ports, and first and second pass holes. The first discharge port and the first pass hole communicate with the first discharge chamber, while the second discharge port and the second pass hole communicate with the second discharge chamber. The valve mechanism also includes first and second discharge valves mounted on the valve plate and accommodated in the first and second discharge chambers, respectively, a suction reed having a reed valve for selectively opening and closing the suction port, a discharge gasket for sealing the valve plate and the cylinder head, and a discharge muffler. The first and second discharge chambers are separated from each other by the discharge gasket to form respective independent spaces, while the first and second pass holes communicate with the discharge muffler.

Description: Technical Field The present invention relates generally to a relatively compact compressor such as utilized in a refrigerator for home use or a freezer in a show casing and, more particularly, to a valve mechanism or a suction system of such a compressor. Background Art In recent years, a valve mechanism in a compressor have been improved in numerous ways to increase the efficiency of the compressor. However, demands have also been made from the market not only to increase the efficiency of the compressor, but also to suppress noise emission from the compressor. The prior art compressor valve mechanism is disclosed in, for example, the Japanese Laid-open Patent Publication (unexamined) No. 3-175174. Hereinafter, with reference to Figs. 6, 7 and 8, the prior art compressor valve mechanism disclosed in the above mentioned Japanese Laid-open Patent Publication No. 3-175174 will be discussed. Fig. 6 is a sectional view of the prior art valve mechanism in an assembled condition taken along the horizontal direction, Fig. 7 is a longitudinal sectional view of Fig. 6, and Fig. 8 is an exploded view of the prior art valve mechanism. In Figs. 6 to 8, reference numeral 1 represents the valve mechanism, and reference numeral 4 represents a valve plate having two suction ports 2 and two discharge ports 3 both defined therein. A discharge reed valve 22 for selectively opening and closing the discharge ports 3 is retained within a recess 21 defined in the valve plate 4. Reference numeral 23 represents a stopper rivetted at 24 to the valve plate for regulating the lift of the reed valve 22. A suction reed valve 11, a plate-like gasket 12, the valve plate 4, a head gasket 13 and a cylinder head 14 are all bolted to a cylinder 10. The cylinder 10 accommodates therein a piston drivingly coupled with an electric motor (not shown) for axial reciprocating movement within the cylinder 10. The cylinder head 14 has a suction chamber 25 and a discharge chamber 26 defined therein in cooperation with the valve plate 4. The operation of the prior art compressor valve mechanism of the structure described above will now be described. As a result of reciprocating movement of the piston 15, a refrigerant gas within the suction chamber 25 is sucked into the cylinder 10 through the suction ports 2 in the valve plate 4 during opening of the suction reed valve 11 and is subsequently compressed within the cylinder 10 before it is discharged into the discharge chamber 26 in the cylinder head 14 through the discharge ports 3 during opening of the discharge reed valve 22. In the prior art valve mechanism discussed above, however, because the refrigerant gas is simultaneously discharged into the discharge chamber 26 through the two discharge ports 3, refrigerant gas flows interfere with each other to hinder smooth streams of the refrigerant gas, thus lowering the discharge efficiency and the performance of the compressor. Furthermore, because simultaneous discharge of the refrigerant gas from the two discharge ports 3 into the discharge chamber 26 is intermittently performed, very large pulsation and noise are undesirably generated. Also, the discharge reed valve merely has only one resonant mode as streams of the refrigerant gas discharged respectively from the two discharge ports 3 push the discharge reed valve 22 simultaneously and, therefore, it has been difficult to make resonance of the reed valve 22 proper and also to optimize the discharge efficiency at about 3,000 revolutions at 50Hz and also at about 3,600 revolutions at 60Hz. Also, even in the case of the compressor in which the number of revolutions is varied such as an inverter, there has been a problem in that changes in number of revolutions tend to be accompanied by considerable lowering of the efficiency. In addition, since the discharge reed valve 22 merely has the single resonant mode, there has been another problem in that hissing sounds generated by the respective streams of the refrigerant gas discharged from the two discharge ports tend to be enhanced by interference to thereby result in considerable generation of noises. Also, the discharge reed valve 22 is fixed in position within the recess 21 by the stopper 23 and the rivets 24, requiring a complicated mounting and an inefficient assemblage. Japanese Patent Publication (examined) No. 6-74786 discloses a suction system for an electrically-operated sealed compressor in which a muffler having a plurality of chambers partitioned from each other is employed for muffling purpose. However, there has been a problem in that if the muffling feature is given priority, the suction efficiency tends to be lowered accompanied by reduction in performance. Also, since a sucked gas represents an intermittent flow as a result of selective opening and closure of a reed valve, a flow inertia of a refrigerant gas cannot be sufficiently utilized and the charge on a cylinder tends to be lowered. This tendency tends to be enhanced when the muffling performance of the muffler is increased. This sealed compressor requires the muffling performance of the muffler and the suction efficiency to be improved. In the European patent application EP 0 582 712 A1 a hermetic compressor which is applicable to a refrigerant compressor is described. This compressor comprises a valve for improved compression efficiency by decreasing the stagnation of a refrigerant gas in the exhaust hole. Furthermore, two exhaust holes and exhaust leads are provided to prevent excessive compression loss. The present invention has been developed to overcome the above-described disadvantages. It is accordingly an objective of the present invention to provide an improved electrically-operated sealed compressor which has a high discharge efficiency and in which sounds generated as a result of interference of refrigerant gases discharged are of a low level to accomplish noise suppression, and in which pulsation of the refrigerant gas is very small. Another objective of the present invention is to provide an electrically-operated sealed compressor capable of accommodating changes in number of revolutions. A still further objective of the present invention is to provide an electrically-operated sealed compressor in which the discharge valve can easily be mounted to facilitate assemblage. Another objective of the present invention is to provide an electrically-operated sealed compressor in which the stopper and the discharge valve can easily be fixed in position. Still another objective of the present invention is to provide an electrically-operated sealed compressor capable of accomplishing an improvement and maintenance in a muffler over the compressing performance of the compressor without lowering the flow inertia of the refrigerant even if the charge on the cylinder is increased and, hence, the muffling performance is increased. Disclosure of the Invention In accomplishing the above and other objectives, an electrically-operated sealed compressor according to the present invention comprises a cylinder, a cylinder head mounted on the cylinder and having a suction chamber defined therein and first and second discharge chambers defined therein, a piston accommodated in the cylinder, and a valve mechanism. The valve mechanism comprises a suction muffler and a valve plate having at least one suction port defined therein, first and second discharge ports defined therein, and first and second pass holes defined therein. The first discharge port and the first pass hole communicate with the first discharge chamber, while the second discharge port and the second pass hole communicate with the second discharge chamber. The valve mechanism also comprises first and second discharge valves mounted on the valve plate and accommodated in the first and second discharge chambers, respectively, a suction reed having a reed valve for selectively opening and closing the suction port, a discharge gasket for sealing the valve plate and the cylinder head, and a discharge muffler. The first and second discharge chambers are separated from each other by the discharge gasket to form respective independent spaces, while the first and second pass holes communicate with the discharge muffler. This construction eliminates interference of refrigerant gas flows which has been hitherto caused by simultaneous introduction of refrigerant gas into a single discharge chamber through two discharge holes, thus avoiding a lowering of the discharge efficiency. Advantageously, the first and second discharge chambers have different volumes and, hence, the frequencies of pulsation differ in the first and second discharge chambers, thus avoiding an increase in noise which may be caused by a resonance of refrigerant gas flows flowing into the discharge muffler at the same frequency of pulsation. Again advantageously, the first and second pass holes have different diameters. By so doing, refrigerant gas flows pass through the first and second pass holes at different speeds and, hence, the refrigerant gas flows have different frequencies of pulsation when entering the discharge muffler, thus avoiding an increase in noise which may be caused by a resonance of refrigerant gas flows flowing into the discharge muffler at the same frequency of pulsation. The cylinder head may have a mixing chamber defined therein, while the valve plate may have a pass hole defined therein so as to communicate with the mixing chamber and the discharge muffler. In this case, the first and second discharge chambers are substantially separated from the mixing chamber by the discharge gasket but communicate with the mixing chamber via first and second communication holes defined in the cylinder head. This construction is free from a lowering in discharge efficiency which has been hitherto caused by mutual interference of refrigerant gas flows intermittently passing through the two discharge ports. Also, because the mixing chamber acts to reduce and rectify the refrigerant gas flowing towards the discharge muffler, pulsation of the refrigerant gas is relatively small and the refrigerant gas flows are smooth, thus considerably reducing noise generation. Brief Description of the Drawings The above and other objectives and features of the present invention will become more apparent from the following description of preferred embodiments thereof with reference to the accompanying drawings, throughout which like parts are designated by like reference numerals, and wherein: Fig. 1 is an exploded perspective view of a compressor valve mechanism according to a first embodiment of the present invention; Fig. 2 is a sectional view of an essential portion of the valve mechanism of Fig. 1; Fig. 3 is a view similar to Fig. 2, but depicting a modification thereof; Fig. 4 is a view similar to Fig. 2, but depicting another modification thereof; Fig. 5 is a view similar to Fig. 2, but depicting a further modification thereof; Fig. 6 is a sectional view of an essential portion of a conventional compressor valve mechanism; Fig. 7 is another sectional view of the essential portion of the conventional compressor valve mechanism of Fig. 6; and Fig. 8 is an exploded perspective view of the essential portion of the conventional compressor valve mechanism of Fig. 6. Detailed Description of a Preferred Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the attached figures. Fig. 1 is an exploded view of a compressor valve mechanism according to an embodiment of the present invention, while Fig. 2 is a cross-sectional view of an essential portion of the valve mechanism as viewed from an arrow A in Fig. 1. In Figs. 1 and 2, reference numeral 101 represents a piston operable to compress a refrigerant gas in a space within a cylinder 102 when it reciprocatingly moves within the cylinder 102. Reference numeral 103 represents a suction muffler having a muffler intake port 104 defined therein for sucking the refrigerant gas. Reference numeral 105 represents a suction gasket, and reference numeral 106 represents a suction reed having a reed valve 107. Reference numeral 108 represents a valve plate having two suction ports 110 defined therein in alignment with the reed valve 107. Also, the valve plate 108 includes a first discharge port 111, a first discharge valve 112 for selectively opening and closing the first discharge port 111, a first pass hole 112a, a second discharge port 113, a second discharge valve 114 for selectively opening and closing the second discharge port 113, and a second pass hole 114a. The first and second discharge valves 112 and 114 are secured to the valve plate 108 by means of fasteners 115. Reference numeral 116 represents a discharge gasket interposed between the valve plate 108 and a cylinder head 117. By the effect of sealing of the discharge gasket 116, a suction chamber 118 communicating with the suction ports 110 and first and second discharge chambers 119 and 120 respectively communicating with the discharge ports 111 and 113 are formed. The first discharge chamber 119 accommodates the first discharge valve 112 and communicates with the first pass hole 112a, while the second discharge chamber 120 accommodates the second discharge valve 113 and communicates with the second pass hole 114a. Both the first and second pass holes 112a and 114a communicate with the discharge muffler 121. The operation and the effect of the compressor valve mechanism constructed as hereinabove described will now be discussed. As a result of reciprocating movement of the piston 101, a refrigerant gas is introduced from the muffler intake port 104 into the suction chamber 118 through the suction muffler 103 and then drawn into the cylinder 102 from the suction ports 110 by the effect of selective opening and closure of the reed valve 107. The refrigerant gas compressed within the cylinder 102 is discharged into the first and second discharge chambers 119 and 120 after having flowed through the first and second discharge ports 111 and 113 by the effect of selective opening and closure of the first and second discharge valves 112 and 114. Because the first and second discharge chambers 119 and 120 are formed separately, refrigerant gas flows generated by the discharge do not interfere with each other around the first and second discharge valves 112 and 114 and, hence, the refrigerant gas flows smoothly through the first and second discharge ports 111 and 113. Accordingly, a lowering of the discharge efficiency can be avoided which has been hitherto caused by an interference between a flow around the first discharge valve 112 and another flow around the second discharge valve 114. As described hereinabove, the compressor of the present invention comprises a piston 101, a cylinder 102 accommodating the piston 101, a reed valve 107 for selectively opening and closing a suction muffler 103 and suction ports 110, a valve plate 108 having two discharge ports 111 and 113 and two pass holes 112a and 114a, two discharge valves 112 and 114 mounted on the valve plate 108, a cylinder head 117 having a suction chamber 118 and two discharge chambers 119 and 120, a discharge gasket 116 for sealing the valve plate 108 and the cylinder head 117, and a discharge muffler 121. The first discharge chamber 119 accommodates the first discharge valve 112 and communicates with the first discharge port 111 and the first pass hole 112a, while the second discharge chamber 120 accommodates the second discharge valve 114 and communicates with the second discharge port 113 and the second pass hole 114a. Also, the first and second discharge chambers 119 and 120 are completely separated from each other by the discharge gasket 116 to form respective independent spaces, while both the first and second pass holes 112a and 114a communicate with the discharge muffler 121. This construction eliminates interference of refrigerant gas flows which has been hitherto caused by simultaneous introduction of refrigerant gas into a single discharge chamber through two discharge holes, thus avoiding a lowering of the discharge efficiency. As shown in Fig. 3, first and second discharge chambers 122 and 123 may have different volumes, unlike the embodiment shown in Figs. 1 and 2. In the above-described construction, a refrigerant gas is discharged into the first and second discharge chambers 122 and 123 through the first and second discharge ports 111 and 113 by the effect of selective opening and closing of the first and second discharge valves 112 and 114. It is to be noted here that intermittent discharge of the refrigerant gas tends to generate an undesirable pressure pulsation in the discharge chambers, and a relatively large pulsation causes, as a pulsation source, an increase in vibration or noise. According to the present invention, however, because the first and second discharge chambers 122 and 123 have different volumes and, hence, have different frequencies of pulsation, the refrigerant gas flows into the discharge muffler 121 through the first and second pass holes 112a and 114a at the different frequencies of pulsation, thus avoiding an increase in noise which may be caused by a resonance of refrigerant gas flows flowing into the discharge muffler at the same frequency of pulsation. Also, the pulsation in the discharge muffler can be considerably reduced by appropriately determining the volumes of the first and second discharge chambers 122 and 123. As shown in Fig. 4, first and second pass holes 112b and 114b may have different diameters. By the above-described construction, a refrigerant gas is discharged into the first and second discharge chambers 122 and 123 through the first and second discharge ports 111 and 113 by the effect of selective opening and closing of the first and second discharge valves 112 and 114. Thereafter, the refrigerant gas in the first and second discharge chambers 122 and 123 is discharged into the discharge muffler 121 through the first and second pass holes 112b and 114b. Because the two pass holes 112b and 114b have different diameters, refrigerant gas flows pass therethrough at different speeds. Accordingly, the refrigerant gas flows have different frequencies of pulsation when entering the discharge muffler 121, thus avoiding an increase in noise which may be caused by a resonance of refrigerant gas flows flowing into the discharge muffler at the same frequency of pulsation. As shown in Fig. 5, the cylinder head 117 may have a mixing chamber 127 defined therein, which communicates with first and second discharge chambers 119b and 120b through first and second communication holes 125 and 126, respectively. The mixing chamber 127 also communicates with the discharge muffler 121 through a pass hole 128. By the above-described construction, a refrigerant gas is discharged into the first and second discharge chambers 119b and 120b through the first and second discharge ports 111 and 113 by the effect of selective opening and closing of the first and second discharge valves 112 and 114. Because the first and second discharge chambers 119b and 120b are separated from each other, refrigerant gases discharged thereinto do not interfere with each other and, hence, do not lower the discharge efficiency. The refrigerant gases in the first and second discharge chambers 119b and 120b are then introduced into the mixing chamber 127 after having been throttled by the first and second communication holes 125 and 126. Because the discharge of the refrigerant gases is intermittently performed, they pulsate. However, because the refrigerant gases are throttled by the first and second communication holes 125 and 126, such a pulsation is relatively small. Furthermore, the mixing chamber 127 acts as a space alleviating intermittent gas flows flowing into the discharge muffler 121 through the pass hole 128. Accordingly, pulsation inside the discharge muffler 121 is reduced and the refrigerant gas flows smoothly, thus considerably reducing noise generation. It is to be noted here that although in the above-described embodiment the valve plate 108 has been described as having two suction ports 110, it may have only one suction port.

Claims: An electrically-operated sealed compressor comprising: a cylinder (102); a cylinder head mounted on said cylinder (102) and having a suction chamber (118) defined therein and first and second discharge chambers (119, 120) defined therein; a piston (101) accommodated in said cylinder; and a valve mechanism comprising: a suction muffler (103); a valve plate (108) having at least one suction port (110) defined therein; first and second discharge valves (112, 114) mounted on said valve plate (108) and accommodated in said first and second discharge chambers (119, 120), respectively; a suction reed (106) having a reed valve (107) for selectively opening and closing said suction port (110); and a discharge gasket (116) for sealing said valve plate (108) and said cylinder head; characterized by a discharge muffler (121); wherein in said valve plate (108) first and second discharge ports (111, 113) and first and second pass holes (112a, 114a) are defined said first discharge port (111) and said first pass hole (112a) communicating with said first discharge chamber (119), said second discharge port (113) and said second pass hole (114a) communicating with said second discharge chamber (120); wherein said first and second discharge chambers (119, 120) are separated from each other by said discharge gasket (116) to form respective independent spaces; and wherein said first and second pass holes (112a, 114a) communicate with said discharge muffler (121). The electrically-operated sealed compressor according to claim 1, wherein said first and second discharge chambers (119, 120) have different volumes. The electrically-operated sealed compressor according to claim 1, wherein said first and second pass holes (112a, 114a) have different diameters. An electrically-operated sealed compressor comprising: a cylinder (102); a cylinder head mounted on said cylinder (102) and having a suction chamber (118) defined therein, first and second discharge chambers (119b, 120b) defined therein, and a mixing chamber (127) defined therein; a piston (101) accommodated in said cylinder (102); and a valve mechanism comprising: a suction muffler (104); a valve plate (108) having at least one suction port (110) defined therein, first and second discharge valves (112, 114) mounted on said valve plate (108) and accommodated in said first and second discharge chambers (119b, 120b), respectively; a suction reed (106) having a reed valve (107) for selectively opening and closing said suction port (110); and a discharge gasket (116) for sealing said valve plate (108) and said cylinder head; characterized by a discharge muffler (121); wherein in said valve plate (108) first and second discharge ports (111, 113) and a pass hole (128) are defined, said first and second discharge ports (111, 113) communicating respectively with said first and second discharge chambers (119b, 120b), said pass hole (128) communicating with said mixing chamber (127) ; wherein said first and second discharge chambers (119b, 120b) are substantially separated from said mixing chamber (127) by said discharge gasket (116) but communicate with said mixing chamber (127) via first and second communication holes (125, 126) defined in said cylinder head; and wherein said pass hole (128) communicates with said discharge muffler (121).

Inventors: KITA ICHIRO, TANAKA YASUHIKO, UMEOKA IKUTOMO, KITA, ICHIRO, TANAKA, YASUHIKO, UMEOKA, IKUTOMO
Applicants: MATSUSHITA REFRIGERATION, MATSUSHITA REFRIGERATION COMPANY
Application year: 1997
Main classification: F04B39
IPC codes: F04B39