JP2012247105A - Cryogenic refrigerator with scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome defective lubrication by efficiently separating and recovering oil mixed in refrigerant gas ejected from a scroll compressor and detecting that the evaporation temperature is below a predetermined refrigerating temperature to suck the separated and recovered oil to a scroll compression element by the pressure difference, in a cryogenic refrigerator including the scroll compressor.SOLUTION: The cryogenic refrigerator is formed with a refrigerant circulation circuit wherein the refrigerant gas compressed by the scroll compressor flows into an oil separator, a condenser, a receiver tank, an expansion valve and an evaporator and then is compressed in the scroll compressor again. The fluid refrigerant of the receiver tank or part of the fluid refrigerant out of the receiver tank is supplied to the scroll compression element part, while the oil separated by the oil separator is sucked to the low-pressure part or the middle pressure part of the scroll compression element part when the evaporation temperature is reduced below a predetermined temperature, to suppress the temperature increase and the defective lubrication of the scroll compression element part.

Description

  The present invention relates to a technique for obtaining good lubrication of a scroll compressor in an ultra-low temperature refrigeration apparatus.

  The scroll compressor accommodates an electric element of an electric motor configuration and a scroll compression element driven by the electric element in a hermetic container, and the scroll compression element is a fixed scroll in which a spiral wrap is erected on the surface of the end plate And an orbiting scroll that is disposed to face the fixed scroll and has a spiral wrap standing on the surface of the end plate, and orbits as the rotating shaft of the electric element rotates. The fixed scroll wrap and the orbiting scroll wrap are eccentric from each other, and a compression space confined by meshing by mutual contact is formed on this eccentric direction line, and this compression space is the rotation of the rotating shaft of the electric element. Due to the orbiting motion of the orbiting scroll, the size is gradually reduced from the outside toward the inside. As a result, a low pressure chamber, an intermediate pressure chamber, and a high pressure chamber are formed, and the refrigerant gas sucked into the refrigerant gas suction port from the suction pipe communicating with the outer peripheral portion of the compression space to the low pressure chamber is sequentially formed in the low pressure chamber and the intermediate pressure chamber. And it is the structure discharged from the discharge port formed in the center part so that it may communicate with a high pressure chamber, compressing in a high pressure chamber.

  In this way, the refrigerant compressed by the scroll compressor and discharged from the discharge port is condensed by the condenser, the liquid refrigerant decompressed and expanded by the expansion valve is evaporated by the evaporator, and the refrigerant circulation returns to the scroll compressor again. In the refrigeration system that configures the circuit, the internal low-pressure scroll compressor is employed, and the scroll compression is achieved by injecting a part of the liquid refrigerant that has exited the condenser from the compression space of the scroll compression element into the intermediate pressure chamber. Some control the discharge gas temperature of the machine (see Patent Document 1).

JP 2001-047383 A

  As described above, when the refrigerant is compressed by the scroll compressor, a part of the lubricating oil in the scroll compressor is discharged in a state of being mixed in the gas refrigerant and enters the refrigerant circulation circuit constituting the refrigeration apparatus. In particular, in a refrigeration apparatus including a scroll compressor, the refrigerant evaporation temperature in an evaporator into which refrigerant decompressed and expanded by an expansion valve is introduced is a temperature range of −40 ° C. or lower, which is an ultra-low temperature zone, for example, −40 ° C. to − When an ultra-low temperature refrigeration apparatus of about 60 ° C. is configured, the refrigerant circulation amount in the refrigerant circuit constituting the refrigeration apparatus decreases due to the throttling effect of the expansion valve. For this reason, the amount of refrigerant gas sucked into the entrance of the compression space of the scroll compression element is reduced, and accordingly, the amount of lubricating oil sucked into the entrance of the compression space together with the refrigerant gas is also reduced. This results in poor lubrication.

  Further, as described above, when the amount of oil accompanying the decrease in the amount of refrigerant gas sucked into the scroll compression element is insufficient and the supply of lubricating oil to the scroll compression element is insufficient, a fixed space that forms a compression space is formed. The amount of oil required to seal the meshing part due to mutual sliding contact between the scroll wrap and the swing scroll wrap is insufficient, and it becomes difficult to form an oil film necessary for sealing this part. Compressed gas leakage increases, leading to a decrease in refrigeration capacity.

  Further, when a liquid injection circuit for supplying a part of the liquid refrigerant to the intermediate pressure portion of the scroll compression element is provided as in Patent Document 1, in order to suppress the temperature rise of the scroll compression element portion, the liquid injection is performed. Due to the liquid refrigerant, the oil in the intermediate pressure chamber in the compression space is also caused to flow, and there is a concern that the oil lubrication of the scroll compression element is insufficient.

  As described above, when an refrigeration apparatus having an ultra-low temperature of about −40 ° C. to −60 ° C. is configured, a decrease in the amount of oil sucked with a decrease in the amount of refrigerant gas sucked into the entrance of the compression space of the scroll compression element; Insufficient oil lubrication of the scroll compression element is a concern due to the lack of oil in the intermediate pressure chamber caused by the liquid refrigerant to be liquid injected.

  In view of these points, the present invention adopts an internal low-pressure scroll compressor to form an ultra-low temperature refrigeration apparatus. In order to suppress the temperature rise of the scroll compression element, a part of the liquid refrigerant is used in the scroll compression element. In the case where a liquid injection circuit for supplying to the intermediate pressure portion is provided, the lack of lubrication of the scroll compression element is solved by adopting a system for supplying oil to the scroll compression element in accordance with the refrigerant evaporation temperature in the evaporator. Provide technology.

  For this purpose, the present invention is an ultra-low temperature refrigeration apparatus including a scroll compressor, in which oil mixed in refrigerant gas discharged from the scroll compressor is effectively separated and recovered, and the evaporation temperature is below a predetermined freezing temperature. By detecting this, the separated and recovered oil is sucked into the scroll compression element by the pressure difference, thereby eliminating the above-mentioned poor lubrication.

  As one means for this, the cryogenic refrigeration apparatus of the present invention is configured such that the refrigerant gas compressed by the scroll compressor is separated from the oil contained therein by the oil separator, and the refrigerant gas from which the oil has been separated is condensed by the condenser. After that, the liquid refrigerant that enters the receiver tank, exits the receiver tank, passes through the expansion valve, flows into the evaporator for freezing the freezing chamber to an ultra-low temperature, evaporates, and the refrigerant that exits the evaporator The refrigerant circulation circuit compressed by the scroll compressor is constituted again. In this configuration, a part of the liquid refrigerant accumulated in the receiver tank or a part of the liquid refrigerant from the receiver tank until it enters the expansion valve is supplied to the scroll compression element part, and the temperature of the scroll compression element part increases. On the other hand, the oil separated by the oil separator is sucked into the low-pressure part or the intermediate-pressure part of the scroll compression element part when the evaporation temperature falls below a predetermined freezing temperature, thereby lubricating the scroll compression element part. This is to prevent defects.

  According to a first aspect of the present invention, an electric element and a scroll compression element driven by the electric element are accommodated in a vertical sealed container, an oil sump is provided in the bottom of the sealed container, and a lower part of the rotating shaft of the electric element Provided with an oil pump that supplies oil in the oil reservoir to the scroll compression element by rotation of the rotary shaft, and compresses the refrigerant gas sucked from a suction pipe communicating with the scroll compression element by the scroll compression element, A scroll compressor that discharges to the outside of the hermetic container is provided, and the discharged refrigerant gas evaporates in the evaporator the liquid refrigerant that has been decompressed and expanded by an expansion valve via an oil separator, a condenser, and a receiver tank that stores liquid refrigerant. Thereafter, in the ultra-low temperature refrigeration apparatus in which a refrigerant circulation circuit returning to the scroll compression element from the suction pipe is formed again, the oil separator An oil return circuit for supplying the oil separated from the refrigerant to the oil reservoir, and a liquid refrigerant obtained by supercooling a part of the liquid refrigerant accumulated in the receiver tank or the refrigerant exiting the receiver tank with a subcooler. A liquid injection circuit for supplying a part to a low pressure part or an intermediate pressure part of the scroll compression element, and when the refrigerant evaporation temperature of the evaporator is equal to or lower than a predetermined freezing temperature, oil separated from the refrigerant by the oil separator is supplied to the scroll compression element An ultra-low temperature refrigeration apparatus equipped with a scroll compressor, characterized in that an oil injection circuit for supplying the low pressure part or intermediate pressure part is provided.

  According to a second aspect of the present invention, in the first aspect, the oil return circuit includes an oil solenoid valve that opens and closes the oil return circuit based on detection by an oil level detection unit of the oil reservoir, and the liquid injection circuit includes the scroll compression element. A refrigerant solenoid valve that opens and closes the liquid injection circuit based on detection by a temperature detection unit that detects the temperature of the discharged refrigerant gas compressed in step, and the oil injection circuit has a predetermined refrigerant evaporation temperature of the evaporator. An ultra-low temperature equipped with a scroll compressor comprising an oil injection solenoid valve that opens the oil injection circuit below the refrigeration temperature and enables oil supply to the low pressure part or intermediate pressure part of the scroll compression element Refrigeration equipment.

  According to a third aspect of the present invention, there is provided the ultra-low temperature refrigeration apparatus comprising a scroll compressor according to the first or second aspect, wherein the liquid injection circuit and the oil injection circuit have a parallel circuit configuration.

  The fourth invention is the first invention or the second invention, wherein the liquid injection circuit and the oil injection circuit have a parallel circuit configuration, and the liquid refrigerant flowing through the liquid injection circuit and the oil flowing through the oil injection circuit merge. An ultra-low temperature refrigeration apparatus provided with a scroll compressor, wherein the cryocompressor is supplied to a low pressure part or an intermediate pressure part of the scroll compression element.

  According to a fifth invention, in the second invention, the liquid injection circuit including the refrigerant electromagnetic valve and the oil injection circuit including the oil injection electromagnetic valve have a parallel circuit configuration, and the refrigerant electromagnetic valve The cryogenic refrigeration equipped with a scroll compressor is characterized in that the liquid refrigerant that has passed through and the oil that has passed through the oil injection solenoid valve merge and are supplied to the low-pressure part or the intermediate-pressure part of the scroll compression element apparatus.

  A sixth aspect of the invention relates to any one of the first to fifth aspects of the invention, wherein the oil injection circuit has a capillary tube configuration in which part or all of the oil injection circuit limits the oil flow rate to a predetermined flow rate. Ultra low temperature refrigeration equipment equipped with a machine.

  According to a seventh invention, in any one of the first to sixth inventions, the detection that the refrigerant evaporation temperature of the evaporator is equal to or lower than a predetermined refrigeration temperature is a temperature detection unit that detects the refrigerant evaporation temperature, or An ultra-low temperature refrigeration apparatus provided with a scroll compressor, characterized in that it is based on detection of a low pressure sensor that detects low pressure from an outlet of the evaporator to a suction portion of the scroll compression element.

  In the first invention, the temperature increase of the scroll compression element when the refrigerant evaporation temperature in the evaporator is set to an ultra-low temperature is suppressed by the liquid refrigerant supplied from the liquid injection circuit, but the scroll compression element is controlled by the supplied liquid refrigerant. Even when the oil is washed away, the oil in the oil separator is supplied to the scroll compression element by the oil injection circuit, so that the poor lubrication due to the oil shortage of the scroll compression element can be eliminated. Further, the shortage of oil in the oil reservoir is solved by supplying oil from the oil separator from the oil return circuit. In this case, the supply of the liquid refrigerant and the oil is performed by the pressure difference of the refrigeration apparatus, so that the supply can be performed smoothly.

  According to the second aspect of the present invention, the operation of the oil solenoid valve, the refrigerant solenoid valve, and the oil injection solenoid valve causes the temperature increase of the scroll compression element when the refrigerant evaporation temperature in the evaporator is set to a very low temperature. Even if the scroll compressor element oil is washed away by the liquid refrigerant supplied from the oil refrigerant, the oil of the oil separator is supplied to the scroll compressor element by the oil injection circuit, resulting in insufficient oil in the scroll compressor element. Insufficient lubrication due to the oil is eliminated, and the oil shortage in the oil reservoir is eliminated by the oil return circuit. In this case, the supply of the liquid refrigerant and the oil is performed by the pressure difference of the refrigeration apparatus, so that the supply can be performed smoothly.

  In the third invention, since the liquid injection circuit and the oil injection circuit have a parallel circuit configuration, the operation of the liquid injection circuit for suppressing the temperature rise of the scroll compression element and the oil injection circuit for eliminating the shortage of oil in the scroll compression element are provided. Since the action can be performed without interfering with each other, the scroll compressor can be operated stably.

  In the fourth aspect of the invention, the liquid refrigerant supplied from the liquid injection circuit and the oil supplied from the oil injection circuit merge and are supplied to the scroll compression element. Since the structure is simplified and the structure is simplified and the liquid refrigerant and the oil are supplied to the same place at the same time, the temperature increase in the scroll compression element portion can be suppressed and the oil shortage can be performed simultaneously.

  In the fifth aspect of the invention, the operation of each of the oil solenoid valve, the refrigerant solenoid valve, and the oil injection solenoid valve suppresses the temperature rise of the scroll compression element, eliminates the poor lubrication due to insufficient oil in the scroll compression element, and stores the oil. In addition, the liquid refrigerant supplied from the liquid injection circuit and the oil supplied from the oil injection circuit merge and are supplied to the scroll compression element. Since the oil supply location is shared and the structure is simplified, the liquid refrigerant and the oil are supplied to the same location at the same time, so that the temperature increase in the scroll compression element portion can be suppressed and the oil shortage can be performed simultaneously.

  In the sixth aspect of the invention, since the oil flow rate supplied from the oil injection circuit can be limited to a predetermined flow rate, a predetermined amount of oil can be supplied without providing an oil flow rate adjusting valve. The same effects as those of the first to fifth inventions can be obtained.

  In the seventh invention, the solenoid valve of the oil injection circuit is opened when the temperature becomes lower than a predetermined freezing temperature based on the detection of the temperature detection unit or the low pressure sensor. The detection of the oil shortage situation and the operation based thereon can be performed accurately, and the same effects as those of the first to sixth inventions can be obtained.

It is a refrigerant | coolant piping figure which shows the ultra-low temperature freezing apparatus which concerns on this invention. It is a vertical side view of the internal low-pressure type scroll compressor according to the present invention. It is a bottom view of the fixed scroll which comprises the scroll compressor which concerns on this invention. It is a figure which shows the positional relationship of the swing scroll revolved at the time of the driving | operation of the scroll compressor which concerns on this invention, and the injection hole formed in the fixed scroll. It is a figure which shows the positional relationship of the swing scroll revolved at the time of the driving | operation of the scroll compressor which concerns on this invention, and the injection hole formed in the fixed scroll. It is a figure which shows the positional relationship of the swing scroll revolved at the time of the driving | operation of the scroll compressor which concerns on this invention, and the injection hole formed in the fixed scroll. It is a figure which shows the control apparatus of the ultra-low temperature freezing apparatus which concerns on this invention. It is a refrigerant | coolant piping figure which shows 2nd Example of the ultra-low-temperature freezing apparatus which concerns on this invention.

  The ultra-low temperature refrigeration apparatus of the present invention contains an electric element and a scroll compression element driven by the electric element in a vertical sealed container, an oil reservoir is provided at the bottom of the sealed container, and the rotating shaft of the electric element An oil pump that supplies oil in the oil reservoir to the scroll compression element by rotation of the rotary shaft, and compresses the refrigerant gas sucked from a suction pipe communicating with the scroll compression element by the scroll compression element. And a scroll compressor that discharges to the outside of the sealed container, and the discharged refrigerant gas is decompressed and expanded by an expansion valve through an oil separator, a condenser, and a receiver tank that stores liquid refrigerant. In the cryogenic refrigeration apparatus in which a refrigerant circulation circuit is formed that returns to the scroll compression element from the suction pipe after being evaporated, An oil return circuit that supplies oil separated from the refrigerant by the oil separator to the oil reservoir, and a liquid refrigerant in which a part of the liquid refrigerant accumulated in the receiver tank or the refrigerant that has exited the receiver tank is supercooled by the subcooler A liquid injection circuit for supplying a part of the refrigerant to a low-pressure part or an intermediate-pressure part of the scroll compression element, and the oil separated from the refrigerant by the oil separator when the refrigerant evaporation temperature of the evaporator is equal to or lower than a predetermined refrigeration temperature. A configuration including a scroll compressor including an oil injection circuit for supplying a low pressure portion or an intermediate pressure portion of a compression element will be described below with reference to the drawings.

  As shown in FIG. 2, the scroll compressor 100 according to the present invention is formed as a space limited from the scroll compression element 102 to the upper side in the sealed container 101 so that the inside of the vertical sealed container 101 has a low pressure. This is an internal low-pressure scroll compressor in which high-pressure refrigerant gas is discharged into a discharge pressure space 111 (muffler chamber).

  The sealed container 101 is made of a steel plate, and includes a vertically long cylindrical container body 101A extending in the vertical direction, and a bowl-shaped end cap 101B and a bottom cap 101C that are welded and fixed to the upper and lower ends of the container body 101A, respectively. Has been. In the sealed container 101, an electric element 103 as a driving means is accommodated on the lower side, and a scroll compression element 102 driven by a rotating shaft 105 of the electric element 103 is accommodated on the upper side. An upper support frame 104 (referred to as a main frame) is accommodated between the scroll compression element 102 and the electric element 103 in the hermetic container 101. The upper support frame 104 has a bearing portion 106 and a boss accommodating portion 122 in the center. And are formed. This bearing portion 106 is for rotatably supporting the tip (upper end) side of the rotating shaft 105 and is formed to project downward from the center of one surface (lower surface) of the upper support frame 104. ing. The boss accommodating portion 122 is for accommodating a boss 124 of a swing scroll 115 described later, and is formed by recessing the center of the other surface (upper surface) of the upper support frame 104 downward. Yes.

  A lower support frame 107 (referred to as a bearing plate) is accommodated in the sealed container 101 below the electric element 103, and a bearing 108 is formed at the center of the lower support frame 107. The bearing 108 is for pivotally supporting the end (lower end) side of the rotating shaft 105, and is formed to project downward from the center of one surface (lower surface) of the lower support frame 107. A space below the lower support frame 107, that is, a bottom portion in the sealed container 101 is an oil reservoir 162 in which lubricating oil for lubricating the scroll compression element 102 and the like is stored.

  An eccentric shaft 123 is formed at the tip (upper end) of the rotating shaft 105. The eccentric shaft 123 is provided with the center being eccentric from the axis of the rotary shaft 105, and is inserted into the boss 124 of the orbiting scroll 115 via a slide bush and an orbiting bearing (not shown) so that the orbiting scroll 115 can be driven to rotate. Has been.

  The scroll compression element 102 includes a fixed scroll 114 and a swing scroll 115. The fixed scroll 114 includes a circular end plate 116, an involute erection erected on one surface (lower surface) of the end plate 116, or a spiral wrap 117 having a curved line approximate thereto, A peripheral wall 118 erected so as to surround the periphery of the wrap 117, and is provided so as to protrude around the peripheral wall 118 (the other surface side (upper side) of the peripheral wall 118). A flange 119 that is shrink-fitted on the inner surface of the main body 101A is integrally formed. The fixed scroll 114 is compressed by the scroll compression element 102 at the center of the end plate 116 (the center of the fixed scroll 114) while the flange 119 is shrink-fitted and fixed to the inner surface of the container main body 101A all around. A discharge hole 113 is formed through which the refrigerant gas communicates with a discharge pressure space 111 (muffler chamber) formed in the upper side of the sealed container 101. The fixed scroll 114 has the wrap 117 protruding downward. When the flange 119 of the fixed scroll 114 is shrink-fitted and fixed to the inner surface of the container main body 101A around the entire periphery, the inside of the sealed container 101 is divided into an upper discharge pressure space 111 and a lower space 112 by the fixed scroll 114.

  The electric element 103 includes a stator 150 fixed to the hermetic container 101 and a rotor 152 that is disposed inside the stator 150 and rotates within the stator 150. The rotating shaft 105 is fitted to the shaft. The stator 150 is formed of a laminated body in which a plurality of electromagnetic steel plates are laminated, and has a stator winding 151 wound around a tooth portion of the laminated body. The rotor 152 is also formed of a laminate of electromagnetic steel plates, like the stator 150.

  Further, an oil passage 105A is formed inside the rotation shaft 105 along the axial direction of the rotation shaft 105. The oil passage 105A includes a suction port 161 located at the lower end of the rotation shaft 105, and the suction port 161. Is immersed in the lubricating oil stored in the oil sump 162 and opened in the lubricating oil. The oil passage 105A is formed with an oil supply port (not shown) for supplying lubrication at a position corresponding to each of the bearings 106 and 108. With this configuration, when the rotary shaft 105 rotates, the oil reservoir 162 stores the oil. The lubricated oil enters the oil passage 105A from the suction port 161 of the rotating shaft 105 and is pumped upward. Then, the pumped lubricating oil is supplied to the sliding portions of the bearings 106 and 108 and the scroll compression element 102 through the respective oil supply ports.

  The airtight container 101 is compressed by the refrigerant introduction pipe 145 for introducing the refrigerant into the lower space 112 in the airtight container 101 and the scroll compression element 102, and a discharge muffler chamber 128 described later from the discharge hole 113. And a refrigerant discharge pipe 146 for discharging the refrigerant discharged to the upper discharge pressure space 111 in the sealed container 101 to the outside. In this embodiment, the refrigerant introduction pipe 145 is welded and fixed to the side surface of the container body 101A of the sealed container 101, and the refrigerant discharge pipe 146 is fixed to the side surface of the end cap 101B by welding.

  As described above, the refrigerant discharge pipe 146 that discharges the refrigerant gas to the outside of the scroll compressor 100 is connected to the upper discharge pressure space 111 in the sealed container 101, and the lower space 112 in the sealed container 101 is inside. Is connected to a refrigerant introduction pipe 145 for introducing the refrigerant. As a result, a high-pressure discharge pressure space 111 is formed in the upper portion of the sealed container 101, but the low-pressure refrigerant gas sucked into the scroll compression element 102 is scrolled from the state where it flows into the lower space 112 in the sealed container 101. Since it is configured to be sucked into the suction portion of the compression element 102, the lower space 112 in the sealed container 101 is at a low pressure, and the scroll compressor 100 thereby uses the lower space 112 in the sealed container 101. Constitutes an internal low-pressure scroll compressor with low pressure.

  On the other hand, in the configuration of the present embodiment, the upper surface 130 (the surface opposite to the wrap 117) of the end plate 116 of the fixed scroll 114 is configured to face the discharge pressure space 111 formed on the upper side in the sealed container 101. . On the upper surface 130 of the end plate 116 of the fixed scroll 114, a discharge valve connected to the discharge hole 113 and a plurality of release valves are provided adjacent to the discharge valve (the discharge valve and the release valve are not shown). This release valve is provided to prevent refrigerant overcompression, and communicates with the compression space 125 in the compression process of the scroll compression element 102 via a release port (not shown).

  A cover 127 screwed to the fixed scroll 114 is provided in the discharge pressure space 111 on the upper side in the sealed container 101. In the center of the lower surface of the cover 127, a discharge muffler chamber 128 that is recessed from the fixed scroll 114 side toward the discharge pressure space 111 and forms a muffler chamber together with the discharge pressure space 111 is formed. The discharge muffler chamber 128 communicates with the discharge hole 113, and although not shown, the discharge muffler chamber 128 and the discharge pressure space 111 in the upper side of the sealed container 101 are connected through a gap provided between the cover 127 and the fixed scroll 114. Communicate.

  Specifically, when the refrigerant pressure in the compression process in the scroll compression element 102 reaches the discharge pressure before reaching the discharge hole 113, the release valve is opened, and the refrigerant in the compression space 125 passes through the release port. It will be discharged to the outside.

  The orbiting scroll 115 is a scroll that revolves with respect to the fixed scroll 114 that is shrink-fitted and fixed to the inner surface of the container main body 101A as described above. The disk-shaped end plate 120 and one surface (the upper side of the end plate 120) A spiral wrap 121 having an involute shape or a curve approximated to this, and the above-described boss 124 projecting from the other surface (lower surface) of the end plate 120 It consists of The swing scroll 115 is arranged so that the protruding direction of the wrap 121 is upward and the wrap 121 is rotated 180 degrees to the wrap 117 of the fixed scroll 114 so as to face each other, and the compression space 125 is interposed between the wraps 117 and 121 inside. Is formed.

  That is, the wrap 121 of the orbiting scroll 115 is opposed to the wrap 117 of the fixed scroll 114 and meshes so that the front end surfaces of both wraps 121 and 117 are in contact with the bottom surfaces (end plate 116 and end plate 120). In addition, the orbiting scroll 115 is fitted with an eccentric shaft 123 provided eccentrically from the axis of the rotary shaft 105 so as to be rotatable. For this reason, the compression space 125 creates a plurality of spaces in which the two spiral wraps 121 and 117 are eccentric to each other and are in contact with each other on the line in the eccentric direction, and each of these spaces is a compression chamber (low pressure chamber or A plurality of compression chambers such as an intermediate pressure chamber and a high pressure chamber).

  In the fixed scroll 114, a flange 119 provided around the peripheral wall 118 is fixed to the upper support frame 104 via a plurality of bolts (not shown). The swing scroll 115 is supported on the upper support frame 104 by an Oldham ring 148 and an Oldham mechanism 149 including an Oldham key. Thus, the orbiting scroll 115 is configured to perform a turning motion without rotating with respect to the fixed scroll 114.

  Since the orbiting scroll 115 revolves eccentrically with respect to the fixed scroll 114, the eccentric direction and contact position of the two spiral wraps 117 and 121 move while rotating, and the compression chamber is compressed from the outside to the inside. It gradually shrinks while moving toward the space 125. The low-pressure refrigerant gas that first enters the outer compression space 125 and is confined in the low-pressure chamber gradually moves inward while being adiabatically compressed, passes through an intermediate pressure (intermediate pressure chamber), and finally reaches the center (high-pressure chamber). When it reaches, it becomes a high-temperature and high-pressure refrigerant gas. This refrigerant gas is sent out to the discharge pressure space 111 through the discharge hole 113 formed at the center of the fixed scroll 114 and the discharge muffler chamber 128.

  In the cover 127 (inside the thickness of the cover 127), the liquid refrigerant in the receiver tank (liquid receiver) 42 is scrolled through a liquid injection circuit 50A, which will be described later, constituting the refrigerant circuit, as will be described later. A liquid injection passage 144 (a part of a liquid injection circuit 50A described later) for cooling the compressed gas by returning to the intermediate pressure portion of the compression element 102 and evaporating it is formed (shown in FIG. 2). The liquid injection passage 144 branches in the cover 127 and is connected to injection holes 141 and 142 described later. The liquid injection passage 144 is connected to a pipe 140 formed of a hollow tube. One end of the pipe 140 is press-fitted into the liquid injection passage 144 of the cover 127 and the other end is a sleeve 139. Is fixed to the end cap 101B by welding.

  In addition, the end plate 116 of the fixed scroll 114 is formed with injection holes 141 and 142 communicating with the liquid injection passage 144 in the vertical direction. The lower side of both the injection holes 141 and 142 (the swinging scroll 115 side) opens to the wrap 117 and 121 side, and the intermediate pressure portion of the scroll compression element 102 (the discharge hole 113 formed at the center of the fixed scroll 114). The intermediate pressure is communicated immediately before or after the same compression chamber. The pipe 140 is attached between the end cap 101B and the cover 127, and the liquid injection circuit 50A from the receiver tank (liquid receiver) 42 is connected to the connecting pipe 147 connected to the pipe 140 as described later. The piping which comprises is connected and the liquid injection channel | path 144 is formed.

  One injection hole 141 is formed at a position shifted by 180 degrees from the other injection hole 142 with respect to the center of the fixed scroll 114 as shown in FIG. One injection hole 141 is formed on the outside of the wrap 117 erected on the fixed scroll 114 (on the side of the high compression chamber formed on the inside of the wrap 121 of the swing scroll 115), and the other injection hole 142 is , Formed inside the wrap 117 standing on the fixed scroll 114 (on the side of the high compression chamber formed outside the wrap 121 of the swing scroll 115).

  Both injection holes 141 and 142 are formed so as to communicate with the intermediate pressure portion of the scroll compression element 102 via a liquid injection circuit 50A described later. As shown in FIG. 4, before the discharge of the high-pressure gas from the discharge hole 113 is started, the position (close to the high compression chamber in the intermediate compression chamber (the compression chamber) )), And in the step where the scroll compression element 102 compresses the refrigerant, both injection holes 141 and 142 communicated with a liquid injection circuit 50A described later communicate with the intermediate compression chamber.

  Both injection holes 141 and 142 are communicated with the low pressure chamber of the compression space 125 of the scroll compression element 102 so that the liquid refrigerant is supplied to the low pressure chamber of the compression space 125 of the scroll compression element 102 via the liquid injection circuit 50A. However, in the following description, the two injection holes 141 and 142 will be described so as to communicate with the intermediate compression chamber that is the intermediate pressure portion of the compression space 125 of the scroll compression element 102.

  Next, cooling of the compressed gas will be described with reference to FIGS. As will be described later, a part of the liquid refrigerant in the receiver tank 42 or a part of the liquid refrigerant that leaves the receiver tank 42 and enters the expansion valve 43 described later passes through the liquid injection circuit 50A described later. It is assumed that the compressed gas is cooled by returning to the intermediate pressure portion of the scroll compression element 102 and cooling rock 115 is positioned in the vicinity of the final compression stroke.

  As the orbiting scroll 115 revolves from the state shown in FIG. 4, the injection holes 141 and 142 closed by the wrap 121 of the orbiting scroll 115 as shown in FIG. It is located immediately before opening to the space 125). At this time, the discharge of the high-temperature and high-pressure refrigerant gas from the high-pressure chamber (compression space 125) to the discharge hole 113 is completed or is in a state immediately before the end.

  When the orbiting scroll 115 further revolves, as shown in FIG. 6, the wrap 121 of the orbiting scroll 115 is separated from both the injection holes 141 and 142, and the both injection holes 141 and 142 are in the intermediate pressure chamber (compression). Open to space 125). At this time, the liquid refrigerant in the receiver tank 42, which will be described later, returns to the intermediate pressure portion of the scroll compression element 102 via the liquid injection circuit 50A, which will be described later, and evaporates to cool the compressed gas. When the swing scroll 115 further revolves, the same operation as described above is repeated. Thereby, cooling of the compressed gas of the scroll compressor 100 is performed.

  One embodiment of a refrigerant piping diagram showing an ultra-low temperature refrigeration circuit 1 according to the present invention is shown in FIG. 1 is a configuration in which two internal low-pressure scroll compressors are connected in parallel, and shows a configuration of an ultra-low temperature refrigeration system in which two scroll compressors, a scroll compressor 100 and a scroll compressor 100A, are connected in parallel. ing. The scroll compressor 100A has the same configuration as the scroll compressor 100, the refrigerant discharge pipe 146 corresponding to the refrigerant discharge pipe 146 is the refrigerant discharge pipe 145, the refrigerant corresponding to the refrigerant introduction pipe 145 is the refrigerant introduction pipe 145A, and the scroll Since the internal configurations of the compressors 100 and 100A are the same, the same parts are denoted by the same reference numerals.

  The ultra-low temperature refrigeration apparatus according to the present invention may be configured by either one of the scroll compressor 100 or 100A as long as a predetermined ultra-low temperature is obtained, but the embodiment shown below is based on FIG. A case of two compressors 100 and 100A will be described. The refrigerant | coolant in an Example has obtained ultra-low temperature by use of Freon 404A.

  In FIG. 1, in the high-temperature and high-pressure refrigerant gas compressed by the scroll compressors 100 and 100A and discharged from the refrigerant discharge pipes 146 and 146A from the discharge holes 113 through the discharge muffler chamber 128 and the discharge pressure space 111, respectively. Oil is mixed. As shown in FIG. 1, oil in the refrigerant gas is separated into refrigerant gas and oil by an oil separator 40, and the refrigerant gas from which the oil is separated is condensed by a condenser 41 and condensed liquid refrigerant ( Gas refrigerant is mixed in part) into the receiver tank 42 from above, and after the liquid refrigerant exiting from the bottom of the receiver tank 42 is decompressed and expanded by the expansion valve 43, the evaporator 44 After evaporating and cooling a predetermined ultra-low temperature freezing area such as a super showcase or a freezer to an ultra-low temperature, the evaporated refrigerant gas passes through the accumulator 45 and again passes through the refrigerant introduction pipes 145 and 145A to the bottom of the sealed container 101. Flows into the space 112 on the side, passes through the passage between the sealed container 101 and the upper support frame 104 from the space 112 on the lower side, and absorbs the scroll compression element 102. Sucked into parts, it is compressed by the scroll compressor 100 and 100A scroll compression element 102 of the operative to be discharged from the refrigerant discharge tube 146 again and repeats the above circulation.

  If the refrigerant sucked into the scroll compressors 100 and 100A contains liquid refrigerant, the accumulator 45 stores the liquid refrigerant and prevents the liquid refrigerant from returning to the scroll compressors 100 and 100A. Thus, the gas-liquid is separated. Although a single evaporator 44 is shown, when there are a plurality of predetermined ultra-low temperature freezing areas that are food storage areas such as a super showcase and a freezer, a plurality of evaporators 44 are connected in parallel accordingly, and the evaporator 44 The expansion valve 43 is connected every time. The condenser 41 has an air cooling type or a water cooling type, and in the case of the air cooling type, the heat is radiated by the electric fan 41A for condensation. The air cooled by the evaporator 44 is circulated by an electric cooling fan 44A to cool a predetermined ultra-low temperature freezing region such as a super showcase or a freezer to an ultra-low temperature. In addition, 46 is a check valve, 47 is a filter for removing dust in the circulating refrigerant and a filter dryer containing a desiccant that adsorbs moisture, 48 is a strainer, and 49 is a sight glass for visually checking the refrigerant flow from the outside. is there.

  In the embodiment of the present invention, a part of the liquid refrigerant accumulated at the bottom of the receiver tank 42 is scrolled to suppress the temperature rise of the scroll compression element 102 with respect to each of the scroll compressor 100 and the scroll compressor 100A. Liquid injection circuits 50 </ b> A and 50 </ b> B are respectively introduced to the intermediate pressure portion (or low pressure portion) of the compression element 102, and a part of the oil accumulated at the bottom of the oil separator 40 is removed from the intermediate pressure portion (or low pressure) of the scroll compression element 102. Oil injection circuits 51A and 51B to be supplied to the In FIG. 1, the liquid injection circuit 50 </ b> A and the oil are supplied so that the liquid refrigerant supplied from the liquid injection circuit 50 </ b> A and the oil supplied from the oil injection circuit 51 </ b> A merge and flow through the common pipe 140 of the scroll compressor 100. The injection circuit 51A is connected to the connecting pipe 147 so as to be a parallel circuit. Further, the liquid injection circuit 50B and the oil injection circuit 51B are arranged so that the liquid refrigerant supplied from the liquid injection circuit 50B and the oil supplied from the oil injection circuit 51B merge and flow through the common pipe 140 of the scroll compressor 100A. Are connected to the connecting pipe 147 so as to form a parallel circuit.

  Further, as shown in FIG. 1, for each of the scroll compressor 100 and the scroll compressor 100A, the oil accumulated at the bottom of the oil separator 40 is stored in the oil sump 162 at the bottom of each of the scroll compressor 100 and the scroll compressor 100A. Oil return circuits 52A and 52B are provided for returning to the normal position.

  The oil injection circuits 51 </ b> A and 51 </ b> B and the oil return circuits 52 </ b> A and 52 </ b> B have a piping configuration in which the oil flowing through the oil outlet pipe 53 for leading the oil accumulated at the bottom of the oil separator 40 flows from the oil pipe 53. The pipes of the oil injection circuits 51A and 51B are configured to have a capillary tube configuration as a whole and, as shown in FIG. 1, are partially configured to have capillary tubes 68A and 68B.

  In the liquid injection circuit 50A, an electric flow rate adjusting valve 54A that adjusts the flow rate of the liquid refrigerant flowing therethrough to a predetermined value and a temperature detection unit 60 that detects the temperature of the refrigerant gas discharged from the scroll compressor 100 detect a predetermined high temperature. Based on this, the refrigerant solenoid valve 55A for opening the liquid injection circuit 50A is connected in series. Further, the liquid injection circuit 50B is based on detection by an electric flow rate adjusting valve 54B that adjusts the flow rate of the liquid refrigerant flowing therethrough to a predetermined value and a temperature detection unit 60 that detects the temperature of the refrigerant gas discharged from the scroll compressor 100A. A refrigerant solenoid valve 55B that opens the liquid injection circuit 50B is connected in series.

  The oil injection circuit 51A includes an oil injection solenoid valve 56A that opens and closes the oil injection circuit 51A. The oil injection circuit 51B includes an oil injection solenoid valve 56B that opens and closes the oil injection circuit 51B.

  The oil return circuit 52A includes an oil solenoid valve 57A that opens and closes the oil return circuit 52A based on detection by the oil level detection unit 61A that detects the oil level of the oil reservoir 162 at the bottom of the scroll compressor 100. The capillary tube 58A has a flow path resistance that adjusts the flow rate of oil flowing through the oil return circuit 52A to a predetermined value. The oil return circuit 52B includes an oil electromagnetic valve 57B that opens and closes the oil return circuit 52B based on detection by an oil level detection unit 61B that detects the oil level of the oil reservoir 162 at the bottom of the scroll compressor 100A. The capillary tube 58B has a flow path resistance that adjusts the flow rate of oil flowing through the oil return circuit 52B to a predetermined value. Reference numerals 59A, 59B, and 59C denote strainers, respectively. SV1 and SV2 are service valves that can manually close the liquid injection circuits 50A and 50B at the time of repair, inspection, maintenance, etc., and normally open the liquid injection circuits 50A and 50B. SV3 is a service valve that can manually close the oil pipe 53 during repair, inspection, maintenance, etc., and normally opens the liquid injection circuits 50A and 50B.

  The temperature detector 60 that detects the temperature of the high-temperature and high-pressure discharged refrigerant gas of the scroll compressor 100 only needs to detect the refrigerant gas temperature from the discharge hole 113 until it is introduced into the condenser 41, and any location therebetween Any attachment that detects the temperature of the refrigerant in the tank may be used. In FIG. 2, the temperature detection unit 60 is accommodated in the distal end portion (lower end portion) of the pipe 136 that passes through the upper wall of the sealed container 101 and the cover 127, and the refrigerant gas discharged upward from the discharge hole 113 is stored. The structure which detects temperature is shown.

  FIG. 7 shows a control device for the cryogenic refrigeration apparatus according to the present invention. A microcomputer-type control unit 62; as an input signal source of the control unit 62, a temperature detection unit 60, oil level detection units 61A and 61B, two temperature sensors 63 for detecting the outlet / inlet temperature of the evaporator 44, respectively; The temperature sensor 70 detects the temperature of a predetermined ultra-low temperature freezing area or the temperature of the evaporator 44 that is a food storage area such as a super showcase or a freezer, and the oil separator 40 condenses so as to detect the pressure of the high-pressure part of the ultra-low temperature freezing apparatus. A high pressure sensor 64 for detecting the pressure in the refrigerant path toward the evaporator 41, a low pressure sensor 65 for detecting the pressure in the refrigerant path on the outlet side of the evaporator 44 so as to detect the pressure in the low pressure portion of the ultra-low temperature refrigeration apparatus, and the scroll compressor 100 The pressure of the refrigerant gas discharged from the discharge hole 113, the muffler chamber 128 or the discharge pressure space 111 so as to detect the pressure of the high pressure portion A high pressure switch 66A for detecting, a high pressure switch 66B for detecting the pressure of the refrigerant gas discharged from the discharge hole 113, the muffler chamber 128 or the discharge pressure space 111 so as to detect the pressure of the high pressure portion of the scroll compressor 100A, and the like. It is connected.

  The high pressure sensor 64 is for stopping the operation of the scroll compressor 100 and the scroll compressor 100A when the discharge pressure of the scroll compressor 100 and the scroll compressor 100A becomes an abnormally high pressure. When the predetermined high pressure of the discharge pressure of the scroll compressor 100A is detected, the operation of the control unit 62 stops the operation of the scroll compressor 100 and the scroll compressor 100A. For this reason, the high-pressure sensor 64 only needs to detect the refrigerant gas pressure until it is discharged from the scroll compressor 100 and the scroll compressor 100A and introduced into the condenser 41, and is attached to detect any pressure in the piping therebetween. I just need it. Further, the low-pressure sensor 65 may be an attachment that detects the low-pressure refrigerant gas pressure from the outlet of the evaporator 44 to the suction portion of the scroll compressor 100 and the scroll compression element 102 of the scroll compressor 100A. As indicated by a dotted line Y, a connection for detecting the pressure of the piping on the outlet side of the accumulator 45 may be used, and the pressure in the lower space 112 in the sealed container 101 of the scroll compressor 100 or the scroll compressor 100A is detected. It may be attached.

  Further, on the output side of the control unit 62, an inverter circuit 67 that controls the rotation speed of the scroll compressors 100 and 100A based on the detection of the temperature sensor 70, electric flow rate adjusting valves 54A and 54B, and refrigerant solenoid valves 55A and 55B. The oil injection solenoid valves 56A and 56B, the oil solenoid valves 57A and 57B, the expansion valve 43, the condensing electric fan 41A, the cooling electric fan 44A, and the like are connected. If the scroll compressors 100 and 100A are of a constant speed rotary type, the temperature sensor 70 detects that the temperature of a predetermined ultra-low temperature freezing region such as a super showcase or a freezer or the temperature of the evaporator 44 has decreased to the lower limit set temperature. For example, if the control unit 62 stops the operation of the scroll compressors 100 and 100A and the temperature sensor 70 detects that the temperature of the ultra-low temperature freezing region or the evaporator 44 has risen to the upper limit set temperature, the control unit 62 performs scroll compression. It becomes control which restarts the driving | operation of the machine 100 and 100A.

  In the above configuration, when the scroll compressors 100 and 100A are operated, the rotating shaft 105 rotates with the rotation of the electric element 103, and the oil in the oil reservoir 162 is supplied to the scroll compression element 102. Thus, the scroll compression element 102 is lubricated. Further, the rotation of the rotary shaft 105 causes the orbiting scroll 115 to revolve, and the space 112 enters the outer peripheral portion (suction portion) of the compression space 125 formed between the wrap 117 of the fixed scroll 114 and the wrap 121 of the orbiting scroll 115. The refrigerant gas is sucked, and the sucked refrigerant gas is gradually compressed from the outside to the inside through the compression space 125 to become a high-temperature and high-pressure gas, and is discharged from the discharge hole 113 to the discharge pressure space 111 through the muffler chamber 128. Is done. The high-temperature and high-pressure refrigerant gas discharged into the discharge pressure space 111 is discharged from the refrigerant discharge pipes 146 and 146A to the outside of the scroll compressors 100 and 100A (outside the sealed container 1), and the oil contained therein is also discharged simultaneously. Is done.

  Thus, the refrigerant gas discharged from the refrigerant discharge pipes 146 and 146A to the outside of the scroll compressors 100 and 100A (outside the sealed container 101) is introduced into the oil separator 40. Since the mass of the oil is larger than the mass of the refrigerant gas, the refrigerant gas introduced into the oil separator 40 and the oil contained therein are separated, the oil is collected at the bottom of the oil separator 40, and the refrigerant gas is the upper part of the oil separator 40. To the condenser 41 through the check valve 46 and condensed. The liquid refrigerant condensed in the condenser 41 (including the case where gas refrigerant is mixed in part) enters the receiver tank 42 from the upper part thereof, and the liquid refrigerant discharged from the bottom part of the receiver tank 42 passes through the expansion valve 43. After being expanded under reduced pressure, the evaporator 44 evaporates to cool a predetermined ultra-low temperature freezing region such as a super showcase or a freezer to an ultra-low temperature. The refrigerant evaporated in the evaporator 44 flows again into the lower space 112 in the sealed container 101 through the refrigerant introduction pipes 145 and 145A via the accumulator 45, and from the lower space 112 to the upper part of the sealed container 101 and the upper part. The air is sucked into the suction portion of the scroll compression element 102 through the passage between the support frame 104, compressed by the scroll compression element 102 of the scroll compressors 100 and 100A, and discharged again from the refrigerant discharge pipes 146 and 146A. It operates to repeat the above circulation. Note that the degree of superheat of the expansion valve 43 is controlled by a temperature sensor 63 and a control unit 62 that detect the inlet / outlet temperature of the evaporator 44. That is, when the degree of superheat is large, the control unit 62 controls to increase the valve opening degree of the expansion valve 43, while when the degree of superheat is small, the control unit 62 controls the valve opening degree of the expansion valve 43 to be small.

  The ultra-low temperature refrigeration apparatus according to the present invention is operated at a set temperature set to an ultra-low temperature of −40 ° C. or lower, for example, −50 ° C. or −60 ° C., and the evaporation temperature of the evaporator 44 by such refrigerant circulation. Cooling air circulation is performed by the operation of the cooling electric fan 44A, the temperature of a predetermined ultra-low temperature freezing region such as a super showcase or a freezer is decreased, and is cooled to a predetermined ultra-low temperature set to -40 ° C or lower. The When the temperature of the ultra-low temperature freezing region or the temperature of the evaporator 44 decreases to a predetermined lower limit temperature due to this cooling, the temperature sensor 70 detects this temperature, and based on the operation of the control unit 62, scroll compression with constant speed rotation is performed. In the case of the machines 100 and 100A, the operation is stopped, and the operation of the condensing electric fan 41A and the cooling electric fan 44A is stopped. Further, when the scroll compressors 100 and 100A are of the inverter control system, the temperature of the ultra-low temperature refrigeration region or the temperature of the evaporator 44 is lowered, so that the rotation speed of the scroll compressors 100 and 100A is lowered and the temperature is lowered to a predetermined lower limit temperature. In this state, the scroll compressors 100 and 100A are operated at a low speed so as to maintain this temperature. Along with this operation, the opening degree of the expansion valve 43 is also controlled by the controller 62, and the operation of the condensing electric fan 41A and the cooling electric fan 44A is controlled.

  The ultra-low temperature refrigeration apparatus according to the present invention includes the liquid injection circuits 50A and 50B as described above. Accordingly, in the scroll compressor 100, when the temperature detection unit 60 detects a predetermined high temperature, the refrigerant solenoid valve 55A is opened based on the operation of the control unit 62, and the liquid refrigerant at the bottom of the receiver tank 42 is Part of the liquid is supplied from the injection holes 141 and 142 to the low pressure part or the intermediate pressure part of the scroll compression element 102 by the liquid injection circuit 50A, and the temperature rise of the scroll compression element 102 is suppressed. In this case, based on the operation of the control unit 62 according to the temperature detected by the temperature detection unit 60, the flow rate of the liquid refrigerant is large when the temperature difference exceeding the set temperature is large, and the liquid flow when the temperature difference exceeding the set temperature is small. The flow rate of the liquid refrigerant by the electric flow rate adjustment valve 54A is adjusted to a predetermined value so that the flow rate of the refrigerant decreases. The supply of the liquid refrigerant to the low pressure part or the intermediate pressure part of the scroll compression element 102 is caused by a pressure difference due to the pressure in the receiver tank 42 being higher than the low pressure part or the intermediate pressure part of the scroll compression element 102. Done. Thereby, the temperature rise of the scroll compression element 102 is suppressed.

  In the scroll compressor 100A, when the temperature detector 60 detects that the temperature has risen to a predetermined high temperature, the refrigerant solenoid valve 55B is opened based on the operation of the controller 62, and the bottom of the receiver tank 42 is A part of the liquid refrigerant is supplied from the injection holes 141 and 142 to the low pressure part or the intermediate pressure part of the scroll compression element 102 by the liquid injection circuit 50B, and the temperature rise of the scroll compression element 102 is suppressed. In this case, based on the operation of the control unit 62 according to the temperature detected by the temperature detection unit 60, the flow rate of the liquid refrigerant is large when the temperature difference exceeding the set temperature is large, and the liquid flow when the temperature difference exceeding the set temperature is small. The flow rate of the liquid refrigerant by the electric flow rate adjustment valve 54B is adjusted to a predetermined value so that the flow rate of the refrigerant decreases. The supply of the liquid refrigerant to the low pressure part or the intermediate pressure part of the scroll compression element 102 is caused by a pressure difference due to the pressure in the receiver tank 42 being higher than the low pressure part or the intermediate pressure part of the scroll compression element 102. Done. Thereby, the temperature rise of the scroll compression element 102 is suppressed. Note that the temperature detection unit 60 can obtain the same control operation even when attached to the discharge pipe 30 so as to detect the temperature of the hot gas refrigerant discharged from the discharge pipe 30.

  Moreover, the ultra-low temperature refrigeration apparatus according to the present invention includes the oil return circuits 52A and 52B as described above. As a result, in the scroll compressor 100, the oil level detection unit 61A that detects the oil level of the oil sump 162 at the bottom of the scroll compressor 100 detects the lower limit level. The solenoid valve 57A is opened, and the oil accumulated at the bottom of the oil separator 40 passes through the oil pipe 53 and is restricted to a predetermined flow rate by the capillary tube 58A, from the oil return circuit 52A to the oil sump 162 at the bottom inside the sealed container 1. The shortage of oil in the oil sump 162 is resolved. The supply of oil to the oil reservoir 162 is performed by a pressure difference due to the pressure in the oil separator 40 being higher than the pressure of the oil reservoir 162 at the bottom of the sealed container 101.

  In the scroll compressor 100A, the oil level detection unit 61B that detects the oil level of the oil reservoir 162 at the bottom of the scroll compressor 100A detects the lower limit level. The valve 57B is opened, and the oil accumulated at the bottom of the oil separator 40 passes through the oil pipe 53 and is restricted to a predetermined flow rate by the capillary tube 58B, and then from the oil return circuit 52B to the oil sump 162 at the bottom in the sealed container 101. The shortage of oil in the oil sump 162 is resolved. The supply of oil to the oil reservoir 162 is performed by a pressure difference due to the pressure in the oil separator 40 being higher than the pressure of the oil reservoir 162 at the bottom of the sealed container 101.

  Further, the ultra-low temperature refrigeration apparatus according to the present invention is operated at an ultra-low temperature of −40 ° C. or lower, for example, a set temperature set at −50 ° C. or −60 ° C., and as described above, the oil injection circuit 51A, 51B is provided. As a result, in the scroll compressor 100, the oil injection solenoid valve 56A is opened by detecting that the refrigerant evaporation temperature of the evaporator 44 has become equal to or lower than a predetermined refrigeration temperature by an evaporation temperature detection unit PP described later, Oil accumulated at the bottom of the oil separator 40 passes through the oil pipe 53, flows through the common pipe 140 from the oil injection circuit 51A, and is supplied to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 2 through the injection holes 141 and 142. Thus, the lubrication of the scroll compression element 2 is maintained. In this case, in the operation in which the refrigerant evaporation temperature is equal to or lower than the predetermined refrigeration temperature, the temperature of the refrigerant gas discharged from the discharge hole 113 becomes high, so that the oil injection valve 55A is opened as described above, thereby the oil injection circuit. The oil from 51A flows through the common pipe 140, joins the liquid refrigerant from the liquid injection circuit 50A, and is supplied to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102 through the injection holes 141 and 142. The predetermined freezing temperature detected by the evaporating temperature detection unit PP is a predetermined ultra-low temperature of −40 ° C. or lower, but is set to −40 ° C. or −45 ° C. in the embodiment. As a result, the temperature increase of the scroll compression element 2 in the ultra-low temperature operation state is suppressed, and the lack of oil in the scroll compression element 2 is eliminated, and good lubrication is maintained.

  Further, in the scroll compressor 100A, in order to perform the same operation as that in the scroll compressor 100, an evaporating temperature detecting unit PP described later indicates that the refrigerant evaporating temperature of the evaporator 44 has become equal to or lower than a predetermined refrigeration temperature. By detecting, the oil injection solenoid valve 56B is opened, the oil accumulated at the bottom of the oil separator 40 passes through the oil pipe 53, flows through the common pipe 140 from the oil injection circuit 51B, and scrolls through the injection holes 141 and 142. Supplyed to the intermediate pressure portion (intermediate pressure chamber) of the compression element 102, the lubrication of the scroll compression element 102 is maintained. In this case, in the operation in which the refrigerant evaporation temperature is equal to or lower than the predetermined refrigeration temperature, the temperature of the refrigerant gas discharged from the discharge hole 113 is high, and therefore the oil injection circuit is opened by opening the refrigerant solenoid valve 55B as described above. The oil from 51B flows through the common pipe 140, merges with the liquid refrigerant from the liquid injection circuit 50B, and is supplied to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102 through the injection holes 141 and 142. The predetermined freezing temperature detected by the evaporating temperature detection unit PP is a predetermined ultra-low temperature of −40 ° C. or lower, but is set to −40 ° C. or −45 ° C. in the embodiment. As a result, the temperature increase of the scroll compression element 2 in the ultra-low temperature operation state is suppressed, and the lack of oil in the scroll compression element 2 is eliminated, and good lubrication is maintained.

  The evaporating temperature detection unit PP related to the oil injection circuits 51A and 51B is the temperature of the refrigerant gas on the outlet side of the evaporator 44 (the refrigerant path from the evaporator 44 to the suction part of the scroll compressor 100 or the scroll compression element 102 of the 100A). However, in the embodiment, the control unit 62 calculates the refrigerant evaporation temperature of the evaporator 44 based on the detection of the low pressure sensor 65. In this case, the evaporation temperature detection unit PP is This corresponds to the low-pressure sensor 65.

  FIG. 8 is a refrigerant piping diagram of the second embodiment of the cryogenic refrigeration apparatus according to the present invention. Also in this case, as in the first embodiment, the ultra-low temperature refrigeration apparatus according to the present invention may be configured by any one of the scroll compressor 100 or 100A as long as a predetermined ultra-low temperature is obtained. The same parts as those in the first embodiment are denoted by the same reference numerals, and the configuration and operation thereof are the same as those in the first embodiment. The configuration of FIG. 8 is different from the configuration of FIG. 1 in that the inlet of the liquid refrigerant to the liquid injection circuits 50A and 50B is connected to the outlet side pipe of the supercooler 411. For this reason, as in the first embodiment, the refrigerant gas from which the oil is separated by flowing into the oil separator 40 flows into the condenser 41 from the upper part of the oil separator 40 and is radiated and condensed. The liquid refrigerant (including a case where gas refrigerant is mixed in part) whose temperature has been reduced by this heat radiation enters the receiver tank 42 from the top and accumulates at the bottom of the receiver tank 42. The liquid refrigerant exits from the bottom of the receiver tank 42 and is supercooled by the supercooler 411 to lower the temperature (for example, approximately 4 to 5 ° C.), and the supercooled liquid refrigerant is supplied to the expansion valve 43. After flowing in and decompressed and expanded, it flows into the evaporator 44 and evaporates in the evaporator 44, thereby cooling a predetermined ultra-low temperature freezing region such as a super showcase or a freezer to a predetermined ultra-low temperature of -40 ° C or lower. Then, the refrigerant exiting the evaporator 44 is again sucked into the suction portion of the scroll compression element 102 through the refrigerant introduction pipes 145 and 145A via the accumulator 45 and compressed, and again discharged from the refrigerant discharge pipes 146 and 146A. It operates to repeat the above circulation.

  In the second embodiment, a liquid refrigerant accumulated at the bottom of the receiver tank 42 is introduced, and a supercooler 411 for supercooling the liquid refrigerant is provided along with the condenser 41, and heat is radiated by the condenser electric fan 41A. It is the composition which is done. The liquid refrigerant supercooled by the supercooler 411 flows into the expansion valve 43, is decompressed and expanded, flows into the evaporator 44, and operates in the same manner as in the first embodiment.

  In the configuration of the second embodiment, in the scroll compressor 100, the refrigerant solenoid valve 55A is opened based on the operation of the control unit 62 by detecting that the temperature detection unit 60 has risen to a predetermined high temperature. A part of the liquid refrigerant supercooled by the supercooler 411 is supplied to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102 by the liquid injection circuit 50A, and the temperature increase of the scroll compression element 102 is suppressed. In this case, based on the operation of the control unit 62 according to the temperature detected by the temperature detection unit 60, the flow rate of the liquid refrigerant is large when the temperature difference exceeding the set temperature is large, and the liquid flow when the temperature difference exceeding the set temperature is small. The flow rate of the liquid refrigerant by the electric flow rate adjustment valve 54A is adjusted to a predetermined value so that the flow rate of the refrigerant decreases. The supply of the liquid refrigerant to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102 is such that the pressure in the receiver tank 42 is higher than that of the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102. This is done by the pressure difference due to Thereby, the temperature rise of the scroll compression element 102 is suppressed. The temperature detector 60 can obtain the same control operation even when attached to the refrigerant discharge pipe 146 or 146A so as to detect the temperature of the hot gas refrigerant discharged from the refrigerant discharge pipe 146 or 146A. .

  In the scroll compressor 100A, the refrigerant solenoid valve 55B is opened based on the operation of the control unit 62 by detecting that the temperature detection unit 60 has risen to a predetermined high temperature. Part of the supercooled liquid refrigerant is supplied to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102 by the liquid injection circuit 50B, and the temperature rise of the scroll compression element 102 is suppressed. In this case, based on the operation of the control unit 62 according to the temperature detected by the temperature detection unit 60, the flow rate of the liquid refrigerant is large when the temperature difference exceeding the set temperature is large, and the liquid flow when the temperature difference exceeding the set temperature is small. The flow rate of the liquid refrigerant by the electric flow rate adjustment valve 54B is adjusted to a predetermined value so that the flow rate of the refrigerant decreases. The supply of the liquid refrigerant to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102 is such that the pressure in the receiver tank 42 is higher than that of the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102. This is done by the pressure difference due to Thereby, the temperature rise of the scroll compression element 102 is suppressed. The temperature detector 60 can obtain the same control operation even when attached to the refrigerant discharge pipe 146 or 146A so as to detect the temperature of the hot gas refrigerant discharged from the refrigerant discharge pipe 146 or 146A. .

  The oil supply from the oil return circuits 52A and 52B to the oil reservoirs 16 of the scroll compressors 100 and 100A is performed in the same manner as in the first embodiment.

  Further, regarding the operation of the oil injection circuits 51A and 51B, in the scroll compressor 100, the evaporation temperature detection unit PP detects that the refrigerant evaporation temperature of the evaporator 44 has become equal to or lower than a predetermined refrigeration temperature. The oil injection solenoid valve 56A is opened, and the oil accumulated at the bottom of the oil separator 40 is supplied from the oil injection circuit 51A to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 2 to maintain the lubrication of the scroll compression element 2. To do. In this case, in the operation in which the refrigerant evaporation temperature is equal to or lower than the predetermined refrigerating temperature, the temperature of the refrigerant gas discharged from the discharge port 10 is high, so that the oil injection valve 55A is opened as described above, so that the oil injection circuit The oil from 51A merges with the liquid refrigerant from the liquid injection circuit 50A through the common pipe S1, and is supplied from the common pipe 140 to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 2. The predetermined freezing temperature detected by the evaporating temperature detection unit PP is a predetermined ultra-low temperature of −40 ° C. or lower, but is set to −40 ° C. or −45 ° C. in the embodiment. As a result, the temperature increase of the scroll compression element 2 in the ultra-low temperature operation state is suppressed, and the lack of oil in the scroll compression element 2 is eliminated, and good lubrication is maintained.

  Further, in the scroll compressor 100A, in order to perform the same operation as in the scroll compressor 100, the evaporating temperature detecting unit PP detects that the refrigerant evaporating temperature of the evaporator 44 has become equal to or lower than a predetermined freezing temperature. As a result, the oil injection solenoid valve 56B is opened, and the oil accumulated at the bottom of the oil separator 40 is supplied from the oil injection circuit 51B to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102. Maintain the lubrication. In this case, in the operation in which the refrigerant evaporation temperature is equal to or lower than the predetermined refrigeration temperature, the temperature of the refrigerant gas discharged from the discharge hole 113 is high, and therefore the oil injection circuit is opened by opening the refrigerant solenoid valve 55B as described above. The oil from 51B merges with the liquid refrigerant from the liquid injection circuit 50B through the common pipe S2, and is supplied from the common pipe 140 to the intermediate pressure portion (intermediate pressure chamber) of the scroll compression element 102. The predetermined freezing temperature detected by the evaporating temperature detection unit PP is a predetermined ultra-low temperature of −40 ° C. or lower, but is set to −40 ° C. or −45 ° C. in the embodiment. As a result, the temperature increase of the scroll compression element 2 in the ultra-low temperature operation state is suppressed, and the lack of oil in the scroll compression element 2 is eliminated, and good lubrication is maintained.

  With the configuration of the second embodiment, the liquid refrigerant that has exited the receiver tank 42 is guided to the subcooler 411 and is supercooled, so that the temperature of the liquid refrigerant is lower than that of the first embodiment. For this reason, the liquid refrigerant of zero dryness can be led to the supercooler 411, the heat conductivity in the supercooler 411 can be improved, and the HFC pseudo azeotrope refrigerant such as R404A which is difficult to take supercooling is adopted. Sufficient supercooling can be achieved in the refrigeration apparatus, stable operation of the scroll compressors 100 and 100A, increase in refrigeration capacity, and reduction in power consumption due to operation of the scroll compressors 100 and 100A. 1 improvement effect can be expected.

  The ultra-low temperature refrigeration apparatus shown in FIGS. 1 and 8 includes two units of the scroll compressor 100 or 100A. However, in the case of being configured by any one unit, for example, in the case of being configured by the scroll compressor 100 The liquid injection circuit 50B related to the scroll compressor 100A, the oil injection circuit 51B, the piping including the solenoid valve related to the oil return circuit 52B, and the control related thereto are omitted.

The scroll compressor according to the present invention is not limited to the configuration shown in the above embodiment, but can be applied to various types of internal low-pressure types, and various forms of ultra-low temperature refrigeration apparatuses within the technical scope of the present invention. Is included.
It should be noted that if the same operation and effect as described above can be achieved by adopting an internal high-pressure type scroll compressor and configuring an ultra-low temperature refrigeration apparatus similar to FIG. 1 or FIG. It will be included as one embodiment.

40 ... Oil separator 41 ... Condenser 411 ... Supercooler 41A ... Electric fan for condensation 42 ... Receiver tank 43 ... Expansion valve 44 ... Evaporator 44A ... Electric fan for cooling 50A ... Liquid injection circuit 50B ... Liquid injection circuit 51A ... Oil injection circuit 51B ... Oil injection circuit 52A ... Oil return circuit 52B ... Oil return circuit 54A: Electric flow rate adjustment valve 54B ... Electric flow rate adjustment valve 55A ... Solenoid solenoid valve 55B ... Refrigerant solenoid valve 56A ... Oil injection solenoid valve 56B ... Oil injection Solenoid valve 57A ... Solenoid valve for oil 57B ... Solenoid valve for oil 58A ... Capillary tube 58B ... Capillary tube 60 ... Temperature detector 61A ... Oil level detector 61B ... Oil level detector 62 ... Controller 63 ... Temperature sensor for detecting inlet temperature 64 ··· High pressure sensor 65 ··· Low pressure sensor 66A · · · High pressure switch 66B · · · High pressure switch 67 · · · Inverter circuit 70 · · · Ultra-low temperature freezing region Alternatively, a temperature sensor 100 detects the temperature of the evaporator 44... Scroll compressor 100 A... Scroll compressor 101 ... Sealed container 102 ... Scroll compression element 103 ... Electric element 105 ... Rotating shaft 104 ... Upper support frame (main frame)
DESCRIPTION OF SYMBOLS 111 ... Discharge pressure space 113 ... Discharge hole 114 ... Fixed scroll 116 ... End plate of fixed scroll 117 ... Wrap of fixed scroll 115 ... Swing scroll 120 ... Swing scroll End plate 121 ... Wrap of rocking scroll 125 ... Compression space 127 ... Cover 128 ... Discharge muffler chamber 141 ... Injection hole 142 ... Injection hole 144 ... Liquid injection passage 162 ...・ Oil sump PP ... Evaporation temperature detector

Claims (7)

  An electric element and a scroll compression element driven by the electric element are accommodated in a vertical airtight container, an oil sump is provided at the bottom of the airtight container, and the rotating shaft is disposed below the rotating shaft of the electric element. An oil pump that supplies oil in the oil reservoir to the scroll compression element by rotation is provided, and refrigerant gas sucked from a suction pipe communicating with the scroll compression element is compressed by the scroll compression element and discharged out of the sealed container The refrigerant gas discharged is evaporated by the evaporator after the liquid refrigerant decompressed and expanded by the expansion valve through the oil separator, the condenser, and the receiver tank for storing the liquid refrigerant, and then sucked again. In an ultra-low temperature refrigeration apparatus in which a refrigerant circulation circuit returning from a pipe to the scroll compression element is formed, the oil separator An oil return circuit for supplying the separated oil to the oil reservoir; and a part of the liquid refrigerant accumulated in the receiver tank or a part of the liquid refrigerant obtained by supercooling the refrigerant exiting the receiver tank with a supercooler. A liquid injection circuit for supplying a low-pressure part or an intermediate-pressure part of the scroll compression element; and a low-pressure part of the scroll compression element for separating oil separated from the refrigerant by the oil separator when the refrigerant evaporation temperature of the evaporator is equal to or lower than a predetermined refrigeration temperature. Alternatively, an ultra-low temperature refrigeration apparatus provided with a scroll compressor, characterized in that an oil injection circuit for supplying to an intermediate pressure portion is provided.   The oil return circuit includes an oil solenoid valve that opens and closes the oil return circuit based on detection of an oil level detection unit of the oil reservoir, and the liquid injection circuit has a temperature of discharged refrigerant gas compressed by the scroll compression element. A refrigerant solenoid valve that opens and closes the liquid injection circuit based on detection by a temperature detection unit for detecting the oil, and the oil injection circuit opens the oil injection circuit when a refrigerant evaporation temperature of the evaporator is equal to or lower than a predetermined freezing temperature. 2. An ultra-low temperature refrigeration apparatus comprising a scroll compressor according to claim 1, further comprising an oil injection solenoid valve that enables oil supply to a low pressure part or an intermediate pressure part of the scroll compression element.   The ultra-low temperature refrigeration apparatus having a scroll compressor according to claim 1 or 2, wherein the liquid injection circuit and the oil injection circuit have a parallel circuit configuration.   The liquid injection circuit and the oil injection circuit have a parallel circuit configuration, and the liquid refrigerant flowing through the liquid injection circuit and the oil flowing through the oil injection circuit merge to supply to the low pressure part or the intermediate pressure part of the scroll compression element. An ultra-low temperature refrigeration apparatus comprising the scroll compressor according to claim 1 or 2.   The liquid injection circuit having the refrigerant solenoid valve and the oil injection circuit having the oil injection solenoid valve have a parallel circuit configuration, and the liquid refrigerant passing through the refrigerant solenoid valve and the oil injection circuit The ultra-low temperature refrigeration apparatus having a scroll compressor according to claim 2, wherein the oil that has passed through the electromagnetic valve merges and is supplied to the low-pressure part or the intermediate-pressure part of the scroll compression element.   The ultra-low temperature refrigeration provided with a scroll compressor according to any one of claims 1 to 5, wherein a part or all of the oil injection circuit has a capillary tube configuration that limits an oil flow rate to a predetermined flow rate. apparatus.   The detection that the refrigerant evaporating temperature of the evaporator has become equal to or lower than a predetermined refrigeration temperature is made by detecting a low pressure from the outlet of the evaporator to the suction part of the scroll compression element. The ultra-low temperature refrigeration apparatus provided with the scroll compressor according to any one of claims 1 to 6, characterized in that it is based on detection by a low-pressure sensor to be detected.

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