MXPA06005167A - Sensor for hermetic machine - Google Patents

Abstract

A hermetic scroll compressor includes a hermetic shell through which the pressure within the shell is monitored. In one embodiment, a housing is resistance welded into an aperture extending through the shell. An oil filled pressure sensor or a dry type pressure sensor is associated with the housing. The oil filled pressure sensor extends through an aperture in the shell. The dry type pressure sensor is located on the housing outside of the shell. In another embodiment, the shell forms the diaphragm portion of the pressure sensor.

Description

DETECTOR FOR HERMETIC MACHINE FIELD OF THE INVENTION The present invention is concerned with a detector for a hermetic compressor. More particularly, the present invention is concerned with a detector that is designed to be welded to the hermetic cover or shell of the hermetic compressor.

BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION The use of hermetically sealed motor-compressor units has become increasingly prevalent in recent years in refrigeration applications where the motor-compressor units are used to compress refrigerant vapor. The compressor is generally driven by an electric motor that rotates the crankshaft or drive shaft of the compressor at relatively high speeds. These hermetically sealed compressors are designed to operate trouble-free during the life of the motor-compressor unit. While these hermetically sealed compressors do not commonly experience any problems during their lifetime, it may be advantageous to check various refrigerant pressures within the refrigeration system for improved control, protection and for troubleshooting diagnostic problems of both the system and the system. compressor if they occur. An increased number of air conditioning systems or refrigeration systems, which verify the pressure of the refrigerant at one or more sites in the refrigeration circuit, is a requirement. The pressures that are commonly checked include the suction pressure and the discharge pressure that is seen in the compressor. These pressures are traditionally detected using a pressure sensor that is screwed to an accessory located in the suction and / or refrigerant discharge lines adjacent to the compressor. These pressure sensors are relatively expensive and unless it is essential for the proper functioning of the cooling system, the detectors are not installed due to financial considerations. Assuming that a relatively inexpensive pressure detector is available to the refrigeration industry, most refrigeration systems that are currently constructed could be improved by the incorporation of pressure detectors. The pressure detectors could be used for improved control, protection and resolution diagnostic problems of both the system and the compressor itself in virtually all refrigerant systems instead of a limited number of systems. The present invention provides the technique with a welded pressure detector for air conditioning and refrigeration compressors. The welded pressure detector is a low cost component that is easily welded and not expensive to the compressor shell. The welded pressure detector can be an oil filled pressure detector, a dry type pressure detector or a dry type pressure detector where the shell forms the diaphragm for the pressure sensor. The welded pressure detector of the present invention allows the electronic elements that are part of the detection device to be placed external to the shell of the compressor and only the detection mechanism is placed inside the hermetic shell. Additional areas of possibility of application of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, insofar as they indicate the preferred embodiment of the invention, are for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE FIGURES The present invention can be more fully understood from the detailed description and the attached figures, wherein: Figure 1 is a vertical cross-sectional view through the center of a displacement type refrigeration compressor incorporating a pair of pressure detectors according to the present invention; Figure 2 is an enlarged cross-sectional view of one of the pressure detectors shown in Figure 1; Figure 3 is an enlarged cross-sectional view of a pressure sensor according to another embodiment of the present invention. Figure 4 is an enlarged cross-sectional view of a pressure sensor according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The following description of the preferred embodiments is exemplary only by nature and is not intended in any way to limit the invention, its application or uses. Referring now to the Figures, in which like reference numerals designate like parts or corresponding parts in all the various views, a displacement compressor incorporating the pressure detector according to the present invention is shown in Figure 1. generally designed by the reference numeral 10. The compressor 10 comprises a generally cylindrical hermetically sealed shell 12 which is welded at the upper end thereof a cover 14 and at the lower end thereof a base 16 having a plurality mounting legs (not shown) formed integrally therewith. The lid 14 is provided with a refrigerant dischafitting 18 which may have the usual dischavalve (not shown). Other main elements fixed to the shell include a transversely extending partition 22 which is welded around its periphery at the same point that the lid 14 is welded to the shell 12, a main bearing housing 24 which is properly secured to the shell 12, a lower bearing housing 26 which also has a plurality of legs extending radially outward, of which the cover 12 and a pressure sensor 28 welded to the shell 12 and a pressure sensor 28 welded to the lid 14. A motor stator 30 having a generally square cross section but with rounded corners is press fitted to the shell 12. The flat parts between the rounded corners on the stator provide passages between the stator and shell, which facilitate the return flow of the lubricant from the top of the shell to the bottom. A driving shaft or crankshaft 32 having an eccentric crankshaft pin 34 at the upper end thereof is rotatably driven in a bearing 36 in the main bearing housing 24 and a second bearing 38 in the lower bearing housing 26. The crankshaft 32 has at the lower end a concentric bore 40 of relatively ladiameter communicating with a smaller diameter bore radially outwardly 32 extending upward thereof to the upper part of the crankshaft 32. Arranged within the bore 40 finds an agitator 44. The lower portion of the inner shell 12 defines the suction chamber 46 which is partially filled with lubricating oil at a level slightly above the lower end of a rotor 48 and the bore 40 acts as a pump for pumping fluid lubricant to the crankshaft 32 and to the passage 42 and finally to all the various portions of the compressor that require lubrication. The crankshaft 32 is rotationally driven by an electric motor including the stator 30, windings 50 passing therethrough and rotor 48 press fit on the crank 32 and has upper and lower counterweights 52 and 54 respectively. The surface of the main bearing housing 24 is provided with a flat pushing support surface 56 on which is disposed an orbiting displacement member 58 having the usual spiral valve or roll 60 on the upper surface thereof. Projecting down from the lower surface of the orbiting displacement member 58 is a cylindrical hub having a thrust bearing 62 therein and in which a drive bushing or bushing 64 having an internal bore 66 is rotatably disposed therein. the crankshaft pin 34 is disposed in a driven manner. The crankshaft pin 34 has a flat portion on a surface that is ubly coupled with a flat surface (not shown) formed in a portion of the bore 66 to provide a radially flexible drive arrangement., as shown in U.S. Patent 4,877,382, of the applicant, the disclosure of which is incorporated herein by reference. An Oldham coupling 68 is also provided positioned between the orbiting scroll member 58 and the bearing housing 24 and keyed to the orbiting scroll member 58 and a non-orbiting scroll element 70 to prevent rotational movement of the orbiting scroll member 58. The Oldham coupling 68 is preferably of the type disclosed in co-pending U.S. Patent 5,320,506, the disclosure of which is incorporated herein by reference. The non-orbiting scroll member 70 is also provided having a wrap 72 positioned in a splice coupling with the wrapper 60 of the orbiting scroll member 58. The non-orbiting scroll element 70 has a centrally arranged discharge passage 74 which communicates with an open upward recess 76 which in turn is in fluid communication with a discharge muffler chamber 78 defined by the lid 14 and disclosed 22. An annular recess 80 is also formed in the non-orbiting displacement element 70 within the whereby a seal assembly 82 is disposed. The recesses 76 and 80 and the seal assembly 82 cooperate to define axial pressure chambers that receive pressurized fluid that is compressed by the casings 60 and 72 to exert an axial driving force on the element. of non-orbiting displacement 70 to thereby drive the tips of the respective wraps 60, 72 into sealing engagement with n the opposite end plate surfaces. The seal assembly 82 is preferably of the type described in greater detail in U.S. Patent No. 5,156,539, the disclosure of which is incorporated herein by reference. The non-orbiting displacement member 70 is designed to be mounted to the bearing housing 24 in an appropriate manner as disclosed in the aforementioned U.S. Patent No. 4,877,382 or U.S. Patent No. 5,102,316, the disclosure of which is incorporated in the present by reference. The integration of the detectors with the compressor 10 can be carried out in one of two ways. First, the detector can be placed completely inside the shell 12 by itself and the signal conductors can be routed or routed through the shell 12 using a hermetic through-feed. However, this method will expose the sensitive electronic elements that are part of the detector to the hard environment inside the cover 12 which includes both coolant, lubricating oils and external temperature and pressure oscillations. This harsh environment will affect the reliability of the detector. From here, this is a less desirable procedure. In the second method, the electronic components that are part of the device can be placed external to the shell 12 of the compressor 10 and only the detector mechanism itself can be placed inside the shell 12. This procedure avoids exposing the electronic components to the rough environment in the shell 12. When using this second method, it is necessary that the detection mechanism be in close proximity to the electronic components. This is necessary because the signal level (current / voltage, etc.) generated by the detection mechanism is commonly very small (in the milliampere / millivolts range) and must be fed to the electronic components of amplification and processing with As little conductor wire as possible. The pressure sensor 28 uses this second method and achieves both narrow isolation and closeness targets for the electronic components. Referring now to Figure 2, the pressure detector 28 is shown in greater detail. The pressure sensor 28 is an oil filled pressure sensor comprising a housing 100, a body 102, a diaphragm 104, a pressure sensing device 106, electronic signal conditioning components 108 and a protective element or cap 110. The housing 100 is a cup-shaped metal housing that is designed to be welded by resistance within an opening defined by shell 12. Resistance welding is a method where two metal objects with carefully designed geometry are placed between two copper electrodes connected to a low-voltage AC or DC power source. The two electrodes are subjected to a great force which results in the compression of the two pieces of metal being joined. Once the compression force reaches a required level, AC or DC voltage is applied to the electrodes. This results in a very large current (commonly thousands of amperes) flowing from one electrode to the other through the metal parts. This large current produces a high localized temperature increase in the joint or joint. The high temperature melts the two pieces of metal in the desired joint area and sticks together the two pieces of metal. After a carefully controlled time, the current is interrupted and the molten metal is allowed to cool. The cooled area represents the welded joint of the two pieces of metal. Resistance welding is a fairly common process and is widely used in the construction of a compressor due to its low cost, its control capacity and the resulting joint is robust and leak-proof. The body 102 is enlarged in Figure 2 for clarity. The body 102 extends through a bore 112 extending through the housing 100. The body 102 is hermetically sealed within the bore 112 by welding, glass melting or other means known in the art. The body 102 defines an internal bore 114 having an enlarged portion 116, an intermediate cavity or portion 118, a reduced diameter portion 120 and an upper chamber or threaded portion 122. The diaphragm 104 is disposed within the enlarged portion 116 and is laser welded or otherwise attached to a shoulder 124 formed between the enlarged portion 116 and the intermediate portion 118. The intermediate portion 118 is filled with silicone oil or any other type of fluid. The pressure sensing device 106 is laser welded or otherwise attached to a shoulder 126 formed between the reduced diameter portion 120 and the threaded portion 122. The pressure sensing device 106 and the diaphragm 104 seal the silicone oil within the intermediate portion 118. The pressure sensing device 106 includes and pressure sensing chip 128 and a hermetic through-feed 130 for electrical connection to the pressure sensing chip 128.

Electronic signal conditioning components 108 are located within the threaded portion 122 and are electrically connected to the pressure sensing chip 128 through the hermetic through-feed 130. The protective cap 110 is received in a threaded manner or otherwise secured to the portion threaded 122. The protective cap 110 includes an opening 132 through which a plurality of signal conductors 134 extend from the electronic signal conditioning elements 108, for connection to the operating system for the compressor 10. Referring now to the Figure 3, a pressure detector 28 'is illustrated. The pressure sensor 28 'is a direct replacement for the pressure sensor 28. The pressure sensor 28' is a dry type of pressure sensor comprising a housing 200, a pressure sensing device 208, electronic signal conditioning components 208 and a protective element in the form of an encapsulating material 310. The housing 200 is a cup-shaped metal housing that is designed to be welded by resistance to the shell 12. The housing 200 defines a cavity 212 that is open to the shell. outer of the shell 12. The bottom of the cavity 212 defines a diagram 214. The pressure sensing device 206 is glued or otherwise secured to the diaphragm 214 within the cavity 212. The electronic signal conditioning components 208 are located within of the cavity 212 and are electrically connected to the pressure sensing device 206. The encapsulation material 310 fills the cavity 212 by in top of the position of the electronic signal conditioning components 208 to provide protection for the pressure detector 28 '. A plurality of signal conductors 234 extend from the electronic signal conditioning components 208 through the encapsulation material 310 for connection to the operating system for the compressor 10. Referring now to FIG. 4, a pressure sensor 28 is illustrated. ''. The pressure sensor 28 '' is also a direct replacement for the pressure sensor 28. The pressure sensor 28 '' is a dry type of pressure sensor comprising a housing 300, a pressure sensing device 306, electronic components of signal conditioning 308 and a protective encapsulating material 310. The housing 300 is a cup-shaped housing that is integrally formed as part of the shell 12. By integrally forming the housing 300 as an integral part of the shell 12, it is removed the resistance welding operation described above. The housing 300 defines a cavity 312 that is open to the exterior of the shell 12. The bottom of the cavity 312 defines a diagram 314.

The pressure sensing device 306 is glued or otherwise secured to the diaphragm 314 within the cavity 312. The electronic signal conditioning components 308 are located within the cavity 312 and are electrically connected to the pressure sensing device 306. The material Encapsulation 310 fills the cavity 312 above the position of the electronic signal conditioning components 308 to provide protection for the pressure sensor 28". A plurality of signal conductors 334 extend from the electronic signal conditioning components through the encapsulation material 310 for connection to the preparative system for the compressor 10. The description of the invention is only exemplary in nature and thus, variations that do not deviate from the scope of the invention are intended to be within the scope of the invention. Such variations will not be considered as deviation from the spirit and scope of the invention.

Claims (20)

1. CLAIMS 1. A hermetic enclosure characterized in that it comprises: a hermetic shell assembly that defines a cavity for the fluid; a diaphragm disposed adjacent the cavity; a pressure sensing device associated with the diaphragm; the electronic components of signal conditioning in electrical communication with the pressure sensing device. The hermetic enclosure according to claim 1, characterized in that the hermetic shell assembly comprises a shell defining an opening and a secured housing within the opening, the cavity is disposed within the housing. 3. The hermetic enclosure according to claim 2, characterized in that the housing defines a perforation and the pressure detecting device includes a body that extends through the perforation, the body defines the cavity, the diaphragm is attached to the body. 4. The hermetic enclosure according to claim 3, characterized in that the pressure sensing device is attached to the body, the cavity is disposed between the diaphragm and the pressure detecting device, the cavity is filled with a fluid. 5. The hermetic enclosure according to claim 3, characterized in that the electronic components for signal conditioning are arranged in a chamber defined by the body. 6. The hermetic enclosure according to claim 3, characterized in that it also comprises a protective element surrounding the electronic components of signal conditioning. The hermetic enclosure according to claim 6, characterized in that the protective element comprises a cover secured to the body. 8. The hermetic enclosure according to claim 2, characterized in that the cavity comprises a closed cavity, the diaphragm forms a portion of the closed cavity. The hermetic enclosure according to claim 8, characterized in that the pressure detecting device is secured to the diaphragm within the closed cavity. 10. The hermetic enclosure according to claim 9, characterized in that the electronic signal conditioning components are arranged within the closed cavity. The hermetic enclosure according to claim 10, characterized in that it further comprises a protective element surrounding the electronic components for signal conditioning and the protective element comprises an encapsulation material disposed within the closed cavity. 12. The hermetic enclosure according to claim 1, characterized in that the cavity comprises a closed cavity formed integrally with the shell, the diaphragm forms a portion of the closed cavity. The sealed enclosure according to claim 12, characterized in that the pressure sensing device is secured to the diaphragm within the closed cavity. The hermetic enclosure according to claim 13, characterized in that the electronic signal conditioning components are disposed within the closed cavity. 15. The hermetic enclosure according to claim 14, characterized in that the protective element comprises an encapsulation material disposed within the closed cavity. The hermetic enclosure according to claim 1, characterized in that the shell defines an opening further comprising a housing closed by resistance within the opening, the pressure detecting device is attached to the housing and the housing hermetically seals the shell. 17. The hermetic enclosure according to claim 16, characterized in that the pressure detecting device comprises a pressure sensor filled with oil. 18. The hermetic enclosure according to claim 17, characterized in that the pressure sensor filled with oil hermetically seals the shell. 19. The hermetic enclosure according to claim 18, characterized in that the pressure detecting device comprises a dry type pressure sensor. 20. The hermetic enclosure according to claim 1, characterized in that the diaphragm is integral with the shell.