US20080011363A1 - Pressure Control Valve - Google Patents
Pressure Control Valve Download PDFInfo
- Publication number
- US20080011363A1 US20080011363A1 US11/827,095 US82709507A US2008011363A1 US 20080011363 A1 US20080011363 A1 US 20080011363A1 US 82709507 A US82709507 A US 82709507A US 2008011363 A1 US2008011363 A1 US 2008011363A1
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- United States
- Prior art keywords
- pressure
- valve
- sealed space
- controlling valve
- refrigerant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/31—Expansion valves
- F25B41/33—Expansion valves with the valve member being actuated by the fluid pressure, e.g. by the pressure of the refrigerant
- F25B41/335—Expansion valves with the valve member being actuated by the fluid pressure, e.g. by the pressure of the refrigerant via diaphragms
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
- F25B2309/061—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2341/00—Details of ejectors not being used as compression device; Details of flow restrictors or expansion valves
- F25B2341/06—Details of flow restrictors or expansion valves
- F25B2341/068—Expansion valves combined with a sensor
- F25B2341/0683—Expansion valves combined with a sensor the sensor is disposed in the suction line and influenced by the temperature or the pressure of the suction gas
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2500/00—Problems to be solved
- F25B2500/01—Geometry problems, e.g. for reducing size
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
- F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
- F25B9/008—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T137/00—Fluid handling
- Y10T137/7722—Line condition change responsive valves
- Y10T137/7837—Direct response valves [i.e., check valve type]
- Y10T137/7904—Reciprocating valves
- Y10T137/7922—Spring biased
Definitions
- This invention relates to a pressure controlling valve (expansion valve) for controlling exit side pressure of a heat radiator (gas cooler) of a vapor compression system refrigeration cycle. More particularly, the invention is suitable for a supercritical refrigeration cycle using a refrigerant, such as carbon dioxide (CO 2 ) in a supercritical zone.
- a refrigerant such as carbon dioxide (CO 2 ) in a supercritical zone.
- a pressure controlling valve such as the one disclosed in Japanese Unexamined Patent Publication No. 2002-13844 and shown in FIG. 14 has been used to control a degree of superheat of an evaporator exit refrigerant.
- This pressure controlling valve 3 includes a temperature sensitive portion 3 a , the internal pressure of which changes in accordance with a refrigerant temperature on the exit side of an evaporator 4 , a film-like diaphragm 3 c partitioning the temperature sensitive portion 3 a from a space 3 b into which the refrigerant flowing out from the evaporator 4 is led and undergoes displacement in accordance with a pressure change inside the temperature sensitive portion 3 a , a throttle portion 3 d for reducing the pressure of the refrigerant, a valve body 3 e for adjusting an opening of the throttle portion 3 d and displacement transmission means 3 f for transmitting the displacement of the diaphragm 3 c to the valve body 3 e .
- a refrigerant passage 3 g for guiding refrigerant flowing out from the evaporator 4 to the side of diaphragm 3 c is provided to the displacement transmission means 3 f . Consequently, low temperature refrigerant flowing out from the evaporator 4 cools the diaphragm 3 c and even when the gas inside the temperature sensitive portion 3 a undergoes condensation and the condensed droplets absorb heat from external air and evaporate, the inside of the heat sensitive portion 3 a can be sufficiently cooled, thereby making it possible to prevent in advance the pressure inside the heat sensitive portion 3 a from elevating due to the influences of the ambient atmosphere around the heat sensitive portion.
- the pressure controlling valve In a refrigeration cycle using HFC134a for the refrigerant, the pressure controlling valve is used at a temperature below the critical temperature of the refrigerant to detect the temperature of the low pressure refrigerant, and the refrigerant sealed in a heat sensitive portion or sealed space at the upper part of the diaphragm, is used in a gas-liquid two-phase state. Since the refrigerant pressure in this gas-liquid two-phase state is solely determined by the temperature, the pressure controlling valve is always kept at a control pressure corresponding to a detection temperature even when the diaphragm undergoes displacement by the change of the refrigerant pressure in the refrigeration cycle, and consequently the volume of the sealed space (temperature sensitive portion) at the upper part of the diaphragm changes.
- the CO 2 refrigerant is sealed in the sealed space at the upper part of the diaphragm at a density ranging from a saturated solution density at a temperature of 0° C. to a saturated solution density at the critical point of the CO 2 refrigerant with respect to the sealed space volume in a state where the valve body closes the throttle portion. Consequently, the pressure on the exit side of the gas cooler and the exit side temperature of the gas cooler are controlled substantially along an optimal control line on the Mollier diagram and the CO 2 cycle can also be efficiently operated in the critical zone.
- the pressure controlling valve according to Japanese Unexamined Patent Publication No. 9-264622 has the problem that when the change of the control pressure is greater than the diaphragm displacement, the control pressure greatly deviates from the high pressure (optimal pressure) at which COP (Coefficient of Performance) reaches a maximum, and COP drops.
- the pressure controlling valve for use in a refrigeration cycle using CO 2 refrigerant preferably exhibits a small drop of COP relative to the control pressure, but the sealed space (temperature sensitive portion) into which the gas is sealed must be increased in order to reduce the volume change of the pressure controlling valve relative to the valve opening. Accordingly, the pressure controlling valve becomes larger in size and production cost becomes higher.
- the optimal high pressure (the pressure at which COP becomes maximal) also rises when the coolant temperature at the back of the gas cooler rises.
- the high pressure becomes higher, there are problems that durability of the apparatus drops and the temperature of discharging the refrigerant becomes higher.
- a pressure controlling valve for use in a supercritical cycle, particularly in a refrigeration cycle using CO 2 for a refrigerant, that can restrain a control pressure from changing owing to displacement of a resilient member and can prevent an abnormal high pressure and drastic drop of COP (performance coefficient).
- one aspect of the present invention provides a pressure controlling valve wherein a volume ratio Vs/(Vs ⁇ Vo) of a total volume Vs of the sealed space when the valve is fully closed and a total volume Vo of the sealed space when the valve is fully open is at least 1.9.
- the pressure controlling valve according to the invention has a construction in which the volume ratio Vs/(Vs ⁇ Vo) is greater than a value of the volume ratio determined from FIG. 11 with respect to a CO 2 gas density in the sealed space when the valve is fully closed.
- the pressure controlling valve can make the sealed space small and can contribute to the decrease of the change of the control pressure.
- a pressure controlling valve has a construction in which a volume ratio Vs/(Vs ⁇ Vo) of a total volume Vs of a sealed space when the valve is fully closed and a total volume Vo of the sealed space when the valve is fully open is at least 2.4. Consequently, it is possible to make a compact sealed space into which the CO 2 gas is sealed, thereby preventing the optimal high pressure from exceeding an upper limit value of 15 MPa and improving durability of an apparatus.
- a pressure controlling valve has a construction in which a volume ratio Vs/(Vs ⁇ Vo) of a total volume Vs of a sealed space when the valve is fully closed and a total volume Vo of the sealed space when the valve is fully open is greater than a value determined from FIG. 12 . Consequently, it is possible in this case to make a compact sealed space and prevent the optimal high pressure from exceeding the upper limit value.
- a pressure controlling valve according to the invention has a construction in which control pressure is not greater than 14 MPa at a refrigerant temperature of 60° C.
- control pressure is set to 14 MPa or below.
- a pressure controlling valve has a construction in which control pressure is at least 9.5 MPa at a refrigerant temperature of 40° C.
- control pressure is at least 9.5 MPa at a refrigerant temperature of 40° C.
- the optimal high pressure is about 9.5 MPa and has a margin with respect to the upper limit value. Because the COP change with respect to the control pressure drastically drops at a pressure below the optimal high pressure, the control pressure is set to 9.5 MPa or more.
- a space A 1 communicating with the sealed space is formed inside a displacement transmission member 31 hermetically coupled with the resilient member 32 . Consequently, volume of the sealed space can be increased and the volume change with respect to the valve opening of the pressure controlling valve can be decreased. In other words, the change of the control pressure can be decreased.
- opening and closing of the valve is effected by the displacement transmission member 31 coupled with the resilient member 32 .
- opening and closing of the pressure controlling valve is executed by mechanical means.
- a recess portion 35 a is formed in a cover member 35 on the side opposing the resilient member 32 relative to the sealed space A, or a member 7 , 8 having a space communicating with the sealed space connected to the cover member 35 . Accordingly, the volume of the sealed space can be increased and the volume change with respect to the valve opening of the pressure controlling valve can be decreased.
- the resilient member 32 is a diaphragm or bellows.
- FIG. 1 is a schematic view of a refrigeration cycle having an internal heat exchanger and using a pressure controlling valve according to a first embodiment of the present invention.
- FIG. 2 is a sectional view of the pressure controlling valve of the first embodiment of the invention.
- FIG. 3 is a schematic view of a refrigeration cycle using a pressure controlling valve according to a second embodiment of the present invention but not having an internal heat exchanger.
- FIG. 4 is a sectional view of the pressure controlling valve of the second embodiment of the invention.
- FIGS. 5A and 5B are a schematic view of a refrigeration cycle using a pressure controlling valve according to a third embodiment of the present invention but not having an internal heat exchanger and a schematic view of a refrigeration cycle using a pressure controlling valve according to a third embodiment of the present invention and having an internal heat exchanger.
- FIG. 6 is a sectional view of the pressure controlling valve of the third embodiment of the invention.
- FIG. 7 is a graph showing the relationship between a volume ratio of a sealed space of a pressure controlling valve at a refrigerant temperature of 40° C. and a change of quantity of control pressure when the pressure controlling valve changes from a full closure state to a full open state by using a density of the gas sealed in the sealed space as a parameter.
- FIG. 8 is a graph showing the relationship between a volume ratio of a sealed space of a pressure controlling valve at a refrigerant temperature of 60° C. and a change quantity of a control pressure when the pressure controlling valve changes from a full closure state to a full open state by using a density of the gas sealed into the sealed space as a parameter.
- FIG. 9 is a graph showing the relationship between a high pressure of a pressure controlling valve and COP in a refrigeration cycle having an internal heat exchanger by using a refrigerant temperature as a parameter.
- FIG. 10 is a graph showing the relationship between a high pressure of a pressure controlling valve and COP in a refrigeration cycle not having an internal heat exchanger by using a refrigerant temperature as a parameter.
- FIG. 11 is a graph showing a line of a control pressure change width 2 MPa at a refrigerant temperature of 40° C. by plotting a gas sealing density to the abscissa.
- FIG. 12 is a graph showing a line of a control pressure change width 2 MPa at a refrigerant temperature of 60° C. by plotting a gas sealing density to the abscissa.
- FIGS. 13A and 13B are explanatory views useful for explaining a valve closure state and a valve open state of a pressure controlling valve.
- FIG. 14 is a sectional view of a pressure controlling valve according to the prior art.
- FIG. 1 is an explanatory view explaining a refrigeration cycle (supercritical refrigeration cycle) into which an internal heat exchanger is assembled, and which circulates CO 2 as a refrigerant.
- FIG. 2 shows a pressure controlling valve according to the first embodiment of the present invention that is applied to the refrigeration cycle shown in FIG. 1 .
- reference numeral 1 denotes a compressor that sucks in and compresses a CO 2 refrigerant and reference numeral 2 denotes a gas cooler (heat radiator) that cools the refrigerant compressed by the compressor 1 .
- Reference numeral 3 denotes a pressure controlling valve (expansion valve) according to this embodiment.
- This pressure controlling valve 3 has a temperature sensitive portion (sealed space) A into which CO 2 gas is sealed, and controls refrigerant pressure on the exit side of the gas cooler 2 on the basis of the refrigerant temperature on the exit side of the gas cooler 2 . Therefore, the pressure controlling valve operates also as a pressure reducing device that reduces the pressure of the high pressure refrigerant.
- the pressure controlling valve 3 has a valve function for opening and closing a refrigerant passage extending from the gas cooler 2 to the internal heat exchanger 6 and a refrigerant passage extending from the internal heat exchanger 6 to an evaporator 4 .
- the pressure controlling valve 3 will be explained later in further detail.
- the evaporator 4 evaporates a gas-liquid two-phase refrigerant the pressure of which is reduced by the pressure controlling valve 3 , and cools air passing outside the evaporator 4 .
- Reference numeral 5 denotes an accumulator that separates the gaseous refrigerant from the liquid phase refrigerant and temporarily stores excess refrigerant inside the refrigeration cycle.
- Reference numeral 6 denotes the internal heat exchanger that is arranged inside the refrigeration cycle so that refrigerant that flows from the gas cooler 2 to the pressure controlling valve 3 and the refrigerant flowing from the accumulator 5 to the compressor 1 conduct heat-exchange with each other.
- the compressor 1 , the gas cooler 2 , the pressure controlling valve 3 , the evaporator 4 , the accumulator 5 and the internal heat exchanger 6 are connected to one another through piping and constitute a closed circuit. Therefore, CO 2 refrigerant discharged from the compressor 1 is taken into the original compressor 1 through the gas cooler 2 ⁇ internal heat exchanger 6 ⁇ pressure controlling valve 3 ⁇ evaporator 4 ⁇ accumulator 5 ⁇ internal heat exchanger 6 .
- a first flow passage F 1 as a part of the refrigerant flow passage extending from the gas cooler 2 to the internal heat exchanger 6 and a second flow passage F 2 as a part of the refrigerant flow passage extending from the internal heat exchanger 6 to the evaporator 4 through a valve port 33 g are independently formed inside a body 33 of the pressure controlling valve 3 A.
- a first opening 33 e is arranged on the heat sensitive portion and a second opening 33 f for setting an adjustment spring 36 is arranged at a lower part besides an inflow port 33 a connected to the gas cooler ( 2 ) side and an outflow port 33 b connected to the internal hat exchanger side that together constitute the first flow passage F 1 and an inflow port 33 c connected to the internal heat exchanger ( 6 ) side and an outflow port 33 d connected to the evaporator ( 4 ) side that together constitute the second flow passage F 2 .
- a displacement transmission member 31 having a valve portion 31 a formed at its distal end is accommodated in the body 33 and the valve portion 31 a of the displacement transmission member 31 opens and closes a valve port 33 g . Consequently, the second flow passage F 2 is opened and closed and the internal heat exchanger 6 and the evaporator 4 are communicated with, and cut off from, each other.
- the temperature sensitive portion is fitted to a first opening 33 e of the body 33 .
- the temperature sensitive portion includes a resilient member 32 , such as a diaphragm or bellows, a cover member 35 , a lower support member 34 , and a sealed space A is formed inside the temperature sensitive portion.
- a recess 35 a for forming the sealed space A is formed at the center of the cover member 35 and the peripheral edge of the resilient member 32 is clamped and fixed by the cover material 35 and the lower support member 34 to form the temperature sensitive portion.
- the resilient member 32 has a thin film made of stainless steel and undergoes deformation and displacement in accordance with the pressure difference between the inside and the outside of the sealed space A.
- the lower support member 34 has a cylindrical portion 34 a and a flange portion 34 b , and a screw portion formed around the outer circumference of the cylindrical portion 34 a is mated with the first opening 33 e of the body 33 , thereby fixing the temperature sensitive portion to the body 33 .
- a filling pipe 35 b is fitted to the cover member 35 and a gas, such as CO 2 is sealed from the filling pipe 35 b into the sealed space A. The filling pipe 35 b is closed after the gas is sealed.
- One of the end portions 31 b of the displacement transmission member 31 that extends upward from the valve portion 31 a through the cylindrical portion 34 a of the lower support member 34 is fixed to the resilient member 32 and a clearance B having an annular sectional shape is defined between the inner surface of the cylindrical portion 34 a and the outer peripheral surface of the displacement transmission member 31 .
- This clearance B communicates with the first flow passage F 1 connected to the exit side of the gas cooler 2 .
- the refrigerant on the exit side of the gas cooler 2 flows into the clearance B and the refrigerant temperature is transmitted to the gas inside the sealed space A.
- the pressure of the refrigerant on the exit side of the gas cooler 2 operates on the resilient member 32 .
- a cavity (space A 1 ) 31 d communicating with the sealed space A of the temperature sensitive portion is formed at an end portion 31 b of the displacement transmission member 31 .
- a through-hole 32 a is naturally formed in the resilient member 32 , and the sealed space A and the cavity (space A 1 ) 31 d communicate with each other through this through-hole 32 a .
- the sealed space of the temperature sensitive portion can be set to the sum of the sealed space A+space A 1 and the sealed space can be expanded, so that accuracy of the temperature sensitive portion can be improved.
- An adjustment nut 37 meshes with the other end portion 31 c of the displacement transmission member 31 extending downward below the valve portion 31 a through the valve port 33 g .
- An adjustment spring 36 for forcing the valve portion 31 a of the displacement transmission member 31 in the closing direction of the valve is interposed between the lower surface of the valve port 33 g and the adjustment nut 37 .
- An initial set load of the adjustment spring 36 (elastic force under the closure state of the valve port 33 g ) can be arbitrarily adjusted by turning the adjustment nut 37 .
- the adjustment spring 36 , adjustment nut 37 , and so forth, are disposed inside a downstream space 37 as a part of the second flow passage F 2 connected to the entry side of the evaporator 4 .
- the valve closing force of the displacement transmission member 31 is acquired by the internal pressure inside the sealed space (A+A 1 ) and the adjustment spring 36
- the valve opening force of the displacement transmission member 31 is acquired by the refrigerant pressure on the exist side of the gas cooler 2 .
- the pressure controlling valve 3 A is opened and closed in accordance with the balance of both of the valve opening and closing forces.
- the internal pressure of the sealed space (A+A 1 ) changes depending on the refrigerant temperature on the exit side of the gas cooler 2 flowing into the clearance B, and as the opening of the valve port 33 g thus changes, the refrigerant pressure on the exist side of the internal heat exchanger 6 is controlled.
- FIG. 9 is a graph showing the relationship between the high pressure and COP by plotting the cases of the outlet refrigerant temperature of 40° C., 50° C. and 60° C. when the internal heat exchanger 6 is used, the temperature of the evaporator 4 is 20° C. and the superheat quantity (the degree of superheat) of the taken-in refrigerant of the compressor 1 is 20° C., respectively.
- the pressure controlling valve 3 ( 3 A) used for the cycle of the CO 2 refrigerant regulates the high pressure of the cycle to the pressure at which COP becomes maximal with respect to the exit refrigerant temperature of the gas cooler 2 . Therefore, the pressure controlling characteristics are regulated by the sealed gas density, etc, of the heat sensitive portion (sealed space) of the pressure controlling valve 3 ( 3 A) so as to achieve the temperature-pressure characteristics indicated by a dashed line in FIG. 9 .
- the CO 2 gas or a mixture of the CO 2 gas and a small amount of an inert gas, such as nitrogen gas is sealed into the temperature sensitive portion (sealed space) of the pressure controlling valve 3 ( 3 A). Since the CO 2 gas reaches a supercritical state at a temperature of about 31° C. or above, the volume of the sealed space A or (A+A 1 ) into which the gas is sealed changes, with the displacement of the resilient member 32 , such as the diaphragm or the bellows, so that the pressure inside the sealed space changes even though the exit refrigerant temperature of the gas cooler 2 does not change.
- an inert gas such as nitrogen gas
- the pressure controlling valve 3 opens and closes the valve in accordance with the displacement of the resilient member 32 . Therefore, when the valve is open as shown in FIG. 13A , the resilient member 32 deforms to a convex state in the down direction, but when the flow rate of the refrigerant increases and the valve lift quantity becomes great, the resilient member 32 undergoes displacement upward and the volume of the sealed space of the temperature sensitive portion becomes small. The sealing density of the gas increases and the pressure rises, too. Consequently, the control pressure increases when the opening of the pressure controlling valve 3 increases as shown in FIG. 13B .
- the drop of COP relative to the control pressure is preferably as small as possible.
- the sealed space into which the gas is sealed must be increased. In this embodiment, therefore, the sealed spaces A, A+A 1 are increased by forming the recess portion 35 a on the cover member 35 and/or forming the cavity portion 31 d in the displacement transmission member 31 .
- FIGS. 7 and 8 represent the degree of the change of the control pressure when the valve changes from the full closure state to full open state with respect to the volume ratio of the sealed space at the refrigerant temperatures of 40° C. and 60° C., respectively, by using the sealed gas density as a parameter.
- the volume ratio is defined by Vs/(Vs ⁇ Vo) where Vs is the total volume of the sealed space at the time of closing of the valve and Vo is the total volume of the sealed space at the time of opening of the valve.
- the volume ratio represents how many times of volume (Vs) of the volume change quantity (Vs ⁇ Vo) owing to opening/closing of the valve is necessary relative to the change of the control pressure.
- FIG. 7 shows the necessary volume ratio at a refrigerant temperature of 40° C.
- the volume ratio rapidly increases from a pressure change of not greater than 1 MPa at a relatively low sealing density (300 kg/m 3 ) used as the pressure controlling valve 3 though the value changes dependent on the sealed gas density.
- a relatively high sealing density 600 kg/m 3
- the volume ratio rapidly increases from the pressure change of below 2 MPa and the necessary volume of the sealed space becomes great.
- the sealing density represents the density with respect to the volume of the sealed space at the closure of the valve.
- the volume ratio rapidly increases from below 2 MPa in the case of the sealing density of 300 kg/m 3 , and rapidly increases from below 4 MPa in the case of the sealing density of 600 kg/m 3 , and the necessary volume of the sealed becomes great.
- the change of the control pressure is preferably 1 to 2 MPa when the refrigerant temperature is 40° C. and 2 to 4 MPa at the refrigerant temperature of 60° C.
- the pressure change width at the COP drop ratio of 10% is 3 MPa at the refrigerant temperature of 40° C., 4.2 MPa at the refrigerant temperature of 50° C. and 6.7 MPa at the refrigerant temperature of 60° C.
- the same COP drop ratio is scored with a pressure change width of at least twice at the refrigerant temperatures of 50° C. and 60° C. with respect to the pressure change width at the refrigerant temperature of 40° C.
- the change width of the control pressure at the refrigerant temperature of 60° C. is about twice the change width at a refrigerant temperature of 40° C., but an equal level of the COP drop ratio of the cycle can be obtained.
- FIG. 10 shows the COP change of the cycle with respect to the control pressure when the internal heat exchanger 6 is not used. Because the pressure change width at the same COP drop ratio is greater than when the internal heat exchanger 6 shown in FIG. 9 is used, COP does not greatly drop even when the pressure controlling valve 3 of this embodiment is used in the case where the internal heat exchanger 6 is not used.
- FIG. 11 is a graph showing the relationship between the volume ratio of the sealed space at the refrigerant temperature of 40° C. in FIG. 7 and the change quantity of the control pressure when the valve changes from the full closure to the full open state with the sealed gas density as a parameter.
- the abscissa represents the sealing density and the ordinate does the volume ratio.
- the graph shows the line of the control pressure change width 2 MPa at the refrigerant temperature of 40° C.
- At least the volume ratio is set to 1.9 or more (at the gas sealing density of 300 kg/m 3 );
- volume ratio is made greater than the solid line in FIG. 11 with respect to the gas sealing density.
- the optimal high pressure (the pressure at which COP becomes maximal) rises, too, when the refrigerant temperature at the exit of the gas cooler 2 rises.
- the high pressure becomes higher, however, the problems occur in that durability of the apparatus drops and the discharge temperature of the compressor 1 rises. For this reason, a pressure of about 15 MPa is set in many cases as the upper limit value of the high pressure.
- the optimal high pressure is about 14 MPa when the refrigerant temperature is 60° C. and often exceeds the upper limit value of 15 MPa if the change of the control pressure is large.
- the COP change with respect to the control pressure is small when the refrigerant temperature is 60° C. as shown in FIG. 9 .
- the lower limit value of the control pressure is set to 12 MPa, therefore, a margin width of about 3 MPa can be acquired with respect to the upper limit value.
- FIG. 12 is a graph showing the relation between the volume ratio of the sealed space at the refrigerant temperature of 60° C. in FIG. 8 and the change quantity of the control pressure when the valve changes from the full closure to the full open with the sealed gas density as a parameter.
- the abscissa represents the sealing density and the ordinate does the volume ratio.
- the graph shows the line of the control pressure change width 3 MPa at the refrigerant temperature of 60° C.
- At least the volume ratio is set to 2.4 or more (at the gas sealing density of 300 kg/m 3 ); or
- volume ratio is made greater than the solid line in FIG. 12 with respect to the gas sealing density
- the optimal high pressure is about 9.5 MPa at the refrigerant temperature of 40° C. and has a margin to the upper limit pressure. Since the COP change with respect to the control pressure drastically drops below the optimal high pressure, a large COP change can be prevented even when the control pressure exhibits some variance when the pressure at the opening of the pressure controlling valve 3 is the optimal high pressure.
- FIG. 3 is an explanatory view useful for explaining the refrigeration cycle of the CO 2 refrigerant without incorporating the internal heat exchanger.
- FIG. 4 shows a pressure controlling valve 3 B according to the second embodiment of the invention that is applied to the refrigeration cycle shown in FIG. 3 .
- the same reference numeral is used to identify the same constituent member as in FIG. 1 .
- reference numeral 1 denotes the compressor for sucking and compressing the CO 2 refrigerant.
- Reference numeral 2 denotes the gas cooler for cooling the refrigerant compressed by the compressor 1 .
- the pressure controlling valve 3 ( 3 B) for controlling the refrigerant pressure on the exit side of the gas cooler 2 on the basis of the refrigerant temperature on the exit side of the gas cooler 2 is arranged on the exit side of the gas cooler 2 and operates as a pressure reducing device for reducing the pressure of the high pressure refrigerant.
- Reference numeral 4 denotes the evaporator for evaporating the gas-liquid two-phase refrigerant the pressure of which is reduced by the pressure controlling valve 3 .
- Reference numeral 5 denotes the accumulator for separating the gaseous phase refrigerant from the liquid phase refrigerant and temporarily storing the excess refrigerant inside the refrigeration cycle.
- the compressor 1 , the gas cooler 2 , the pressure controlling valve 3 , the evaporator 4 and the accumulator 5 are connected to one another through piping and form a closed circuit.
- the pressure controlling valve 3 B according to the second embodiment of the invention and shown in FIG. 3 is used in the cycle not using the internal heat exchanger. Therefore, only a flow passage F as a part of the refrigerant flow passage extending from the gas cooler 2 to the evaporator 4 through the valve port 33 g is formed inside the body 33 of the pressure controlling valve 3 B.
- the second opening 33 f of the body 33 of the pressure controlling valve 3 B is closed, and the extension portion below the valve portion 31 a of the displacement transmission member 31 , the adjustment spring 36 and the adjustment nut 37 are omitted.
- the cavity 31 d formed at one of the ends 31 b of the displacement transmission member 31 is omitted. Accordingly, the sealed space A is formed by the recess portion 35 a disposed in the cover member 35 .
- the rest of the constructions are the same as those of the first embodiment and the explanation will be omitted.
- the gas sealed into the sealed space A Only the internal pressure by the gas sealed into the sealed space A, into which the refrigerant temperature on the exit side of the gas cooler 2 flowing into the clearance B is transmitted, operates as the valve closing force of the displacement transmission member 31 in the second embodiment, and the refrigerant pressure on the exit side of the gas cooler 2 operates as the valve opening force.
- the gas sealed into the sealed space A also performs the function of the adjustment spring 36 .
- the CO 2 gas that changes the internal pressure in accordance with the temperature and a small amount of an inert gas, such as a nitrogen gas that generates an internal pressure of a substantially constant level without changing the internal pressure in accordance with the temperature within the temperature range of the detection object are mixed and sealed.
- the recess portion 35 a of the cover member 35 of the resilient member 32 is made as large as possible to secure the volume ratio by increasing the volume of the sealed space A as the temperature sensitive portion.
- FIGS. 5A and 5B are schematic views of the refrigeration cycles of the CO 2 refrigerant in the case where the pressure controlling valve 3 C according to the third embodiment is used, but the internal heat exchanger 6 is not used and in the case where the internal heat exchanger 6 is used, respectively.
- FIG. 6 shows the pressure controlling valve 3 C according to the third embodiment of the invention.
- the arrangement of the constituent elements in the schematic view of the refrigeration cycle shown in FIG. 5A is basically the same as that of the refrigeration cycle shown in FIG. 3 with the exception of the construction of the pressure controlling valve 3 .
- the schematic view of the refrigeration cycle in FIG. 5B is basically the same as the refrigeration cycle shown in FIG. 1 and the explanation will be therefore omitted.
- 5A and 5B has a capillary tube 7 connected to the sealed space A as the heat sensitive portion and a temperature sensitive cylinder 8 arranged at the distal end of the capillary tube 7 .
- This temperature sensitive cylinder 8 is disposed to keep contact with the exit piping of the gas cooler 2 .
- only one flow passage F is formed inside the body 33 .
- This flow passage F is used as a part of the refrigerant flow passage extending from the gas cooler 2 to the evaporator 4 through the valve port 33 g when the pressure controlling valve 3 C is used for the cycle not having the internal heat exchanger 6 shown in FIG. 5A and when used for the cycle using the internal heat exchanger 6 shown in FIG. 5B , the flow passage F is used as a part of the refrigerant flow passage extending from the internal heat exchanger 6 to the evaporator 4 through the valve port 33 g .
- the cavity 31 d is not formed at one of the ends of the displacement transmission member 31 .
- the capillary tube 7 having the temperature sensitive cylinder 8 at its distal end is fitted as a member communication with the sealed space A to the cover member 35 and the inside of the capillary tube 7 is connected with the sealed space A. Therefore, the volume of the sealed space into which the gas is sealed can be increased.
- the rest of the constructions are the same as those of the pressure controlling valve 3 A of the first embodiment.
- the valve closing force and the valve opening force of the displacement transmission member 31 operates in the same way as those of the pressure controlling valve 3 A of the first embodiment, but the sealed gas inside the sealed space mainly receives the thermal influences from the heat sensitive cylinder 8 arranged at the exit piping of the gas cooler 2 .
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Abstract
Description
- 1. Field of the Invention
- This invention relates to a pressure controlling valve (expansion valve) for controlling exit side pressure of a heat radiator (gas cooler) of a vapor compression system refrigeration cycle. More particularly, the invention is suitable for a supercritical refrigeration cycle using a refrigerant, such as carbon dioxide (CO2) in a supercritical zone.
- 2. Description of the Related Art
- In a refrigeration cycle using HFC134a as a refrigerant according to the prior art, a pressure controlling valve, such as the one disclosed in Japanese Unexamined Patent Publication No. 2002-13844 and shown in
FIG. 14 has been used to control a degree of superheat of an evaporator exit refrigerant. Thispressure controlling valve 3 includes a temperaturesensitive portion 3 a, the internal pressure of which changes in accordance with a refrigerant temperature on the exit side of anevaporator 4, a film-like diaphragm 3 c partitioning the temperaturesensitive portion 3 a from aspace 3 b into which the refrigerant flowing out from theevaporator 4 is led and undergoes displacement in accordance with a pressure change inside the temperaturesensitive portion 3 a, athrottle portion 3 d for reducing the pressure of the refrigerant, avalve body 3 e for adjusting an opening of thethrottle portion 3 d and displacement transmission means 3 f for transmitting the displacement of thediaphragm 3 c to thevalve body 3 e. Arefrigerant passage 3 g for guiding refrigerant flowing out from theevaporator 4 to the side ofdiaphragm 3 c is provided to the displacement transmission means 3 f. Consequently, low temperature refrigerant flowing out from theevaporator 4 cools thediaphragm 3 c and even when the gas inside the temperaturesensitive portion 3 a undergoes condensation and the condensed droplets absorb heat from external air and evaporate, the inside of the heatsensitive portion 3 a can be sufficiently cooled, thereby making it possible to prevent in advance the pressure inside the heatsensitive portion 3 a from elevating due to the influences of the ambient atmosphere around the heat sensitive portion. - In a refrigeration cycle using HFC134a for the refrigerant, the pressure controlling valve is used at a temperature below the critical temperature of the refrigerant to detect the temperature of the low pressure refrigerant, and the refrigerant sealed in a heat sensitive portion or sealed space at the upper part of the diaphragm, is used in a gas-liquid two-phase state. Since the refrigerant pressure in this gas-liquid two-phase state is solely determined by the temperature, the pressure controlling valve is always kept at a control pressure corresponding to a detection temperature even when the diaphragm undergoes displacement by the change of the refrigerant pressure in the refrigeration cycle, and consequently the volume of the sealed space (temperature sensitive portion) at the upper part of the diaphragm changes.
- In a refrigeration cycle using carbon dioxide (CO2) as the refrigerant, a supercritical condition is reached at a temperature higher than the critical temperature. Therefore, when the diaphragm undergoes displacement and the volume of the sealed space (temperature sensitive portion) at the upper part of the diaphragm changes, the pressure of the sealed refrigerant inside the sealed space changes in accordance with the volume change even at the same refrigerant temperature, and the control pressure of the pressure controlling valve also changes.
- Therefore, in a refrigeration cycle using CO2 refrigerant, a method of controlling high pressure at which a coefficient of performance (COP=Δi/ΔL: Δi is an enthalpy change quantity in the evaporation process, and ΔL is an enthalpy change quantity in the compression process) of the CO2 cycle reaches a maximum with respect to the refrigerant temperature at the exit of the gas cooler (heat radiator) is known from Japanese Unexamined Patent Publication No. 9-264622. In the pressure controlling valve according to Japanese Unexamined Patent Publication No. 9-26422, the CO2 refrigerant is sealed in the sealed space at the upper part of the diaphragm at a density ranging from a saturated solution density at a temperature of 0° C. to a saturated solution density at the critical point of the CO2 refrigerant with respect to the sealed space volume in a state where the valve body closes the throttle portion. Consequently, the pressure on the exit side of the gas cooler and the exit side temperature of the gas cooler are controlled substantially along an optimal control line on the Mollier diagram and the CO2 cycle can also be efficiently operated in the critical zone.
- However, the pressure controlling valve according to Japanese Unexamined Patent Publication No. 9-264622 has the problem that when the change of the control pressure is greater than the diaphragm displacement, the control pressure greatly deviates from the high pressure (optimal pressure) at which COP (Coefficient of Performance) reaches a maximum, and COP drops.
- When the elevation of the control pressure is greater than the diaphragm displacement, the pressure exceeds the maximum of the high pressure before the pressure controlling valve is fully open.
- The pressure controlling valve for use in a refrigeration cycle using CO2 refrigerant preferably exhibits a small drop of COP relative to the control pressure, but the sealed space (temperature sensitive portion) into which the gas is sealed must be increased in order to reduce the volume change of the pressure controlling valve relative to the valve opening. Accordingly, the pressure controlling valve becomes larger in size and production cost becomes higher.
- In the refrigeration cycle using CO2 refrigerant, the optimal high pressure (the pressure at which COP becomes maximal) also rises when the coolant temperature at the back of the gas cooler rises. When the high pressure becomes higher, there are problems that durability of the apparatus drops and the temperature of discharging the refrigerant becomes higher.
- In view of the problems described above, it is an object of the present invention to provide a pressure controlling valve for use in a supercritical cycle, particularly in a refrigeration cycle using CO2 for a refrigerant, that can restrain a control pressure from changing owing to displacement of a resilient member and can prevent an abnormal high pressure and drastic drop of COP (performance coefficient).
- It is a second object of the invention to provide a pressure controlling valve capable of making small a sealed space (temperature sensitive portion) into which a gas is sealed, and holding down the increase of the size and production cost of the valve.
- It is a third object of the invention to provide a pressure controlling valve capable of reducing a high pressure and preventing the drop of durability of an apparatus and rise of a discharge temperature.
- In a pressure controlling valve for occurring to deform a
resilient member 32 by a difference in pressure between a pressure of CO2 gas in a sealed space A corresponding to a refrigerant temperature and highly pressurized CO2 refrigerant in a refrigeration cycle and effecting opening and closing of a valve, one aspect of the present invention provides a pressure controlling valve wherein a volume ratio Vs/(Vs−Vo) of a total volume Vs of the sealed space when the valve is fully closed and a total volume Vo of the sealed space when the valve is fully open is at least 1.9. In this way, the sealed space (temperature sensitive portion) into which the CO2 gas is sealed can be made compact, the change of the control pressure can be made small and the increase of the size and production cost of the pressure controlling valve can be reduced. - The pressure controlling valve according to the invention has a construction in which the volume ratio Vs/(Vs−Vo) is greater than a value of the volume ratio determined from
FIG. 11 with respect to a CO2 gas density in the sealed space when the valve is fully closed. In this case, the pressure controlling valve can make the sealed space small and can contribute to the decrease of the change of the control pressure. - A pressure controlling valve according to another aspect of the invention has a construction in which a volume ratio Vs/(Vs−Vo) of a total volume Vs of a sealed space when the valve is fully closed and a total volume Vo of the sealed space when the valve is fully open is at least 2.4. Consequently, it is possible to make a compact sealed space into which the CO2 gas is sealed, thereby preventing the optimal high pressure from exceeding an upper limit value of 15 MPa and improving durability of an apparatus.
- A pressure controlling valve according to another aspect of the invention has a construction in which a volume ratio Vs/(Vs−Vo) of a total volume Vs of a sealed space when the valve is fully closed and a total volume Vo of the sealed space when the valve is fully open is greater than a value determined from
FIG. 12 . Consequently, it is possible in this case to make a compact sealed space and prevent the optimal high pressure from exceeding the upper limit value. - A pressure controlling valve according to the invention has a construction in which control pressure is not greater than 14 MPa at a refrigerant temperature of 60° C. When the coolant temperature is 60° C., the high pressure is may exceed the upper limit value if the change of the control pressure is great. Therefore, the control pressure is set to 14 MPa or below.
- A pressure controlling valve according to the invention has a construction in which control pressure is at least 9.5 MPa at a refrigerant temperature of 40° C. When the refrigerant temperature is 40C, the optimal high pressure is about 9.5 MPa and has a margin with respect to the upper limit value. Because the COP change with respect to the control pressure drastically drops at a pressure below the optimal high pressure, the control pressure is set to 9.5 MPa or more.
- In the pressure controlling valve according to the invention, a space A1 communicating with the sealed space is formed inside a
displacement transmission member 31 hermetically coupled with theresilient member 32. Consequently, volume of the sealed space can be increased and the volume change with respect to the valve opening of the pressure controlling valve can be decreased. In other words, the change of the control pressure can be decreased. - In the pressure controlling valve according to the invention, opening and closing of the valve is effected by the
displacement transmission member 31 coupled with theresilient member 32. In other words, opening and closing of the pressure controlling valve is executed by mechanical means. - In the pressure controlling valve according to the invention, a
recess portion 35 a is formed in acover member 35 on the side opposing theresilient member 32 relative to the sealed space A, or amember cover member 35. Accordingly, the volume of the sealed space can be increased and the volume change with respect to the valve opening of the pressure controlling valve can be decreased. - In the pressure controlling valve according to the invention, the
resilient member 32 is a diaphragm or bellows. - The present invention will be understood more apparently from the description of the following preferred embodiments when taken in connection with the accompanying drawings.
- In the drawing:
-
FIG. 1 is a schematic view of a refrigeration cycle having an internal heat exchanger and using a pressure controlling valve according to a first embodiment of the present invention. -
FIG. 2 is a sectional view of the pressure controlling valve of the first embodiment of the invention. -
FIG. 3 is a schematic view of a refrigeration cycle using a pressure controlling valve according to a second embodiment of the present invention but not having an internal heat exchanger. -
FIG. 4 is a sectional view of the pressure controlling valve of the second embodiment of the invention. -
FIGS. 5A and 5B are a schematic view of a refrigeration cycle using a pressure controlling valve according to a third embodiment of the present invention but not having an internal heat exchanger and a schematic view of a refrigeration cycle using a pressure controlling valve according to a third embodiment of the present invention and having an internal heat exchanger. -
FIG. 6 is a sectional view of the pressure controlling valve of the third embodiment of the invention. -
FIG. 7 is a graph showing the relationship between a volume ratio of a sealed space of a pressure controlling valve at a refrigerant temperature of 40° C. and a change of quantity of control pressure when the pressure controlling valve changes from a full closure state to a full open state by using a density of the gas sealed in the sealed space as a parameter. -
FIG. 8 is a graph showing the relationship between a volume ratio of a sealed space of a pressure controlling valve at a refrigerant temperature of 60° C. and a change quantity of a control pressure when the pressure controlling valve changes from a full closure state to a full open state by using a density of the gas sealed into the sealed space as a parameter. -
FIG. 9 is a graph showing the relationship between a high pressure of a pressure controlling valve and COP in a refrigeration cycle having an internal heat exchanger by using a refrigerant temperature as a parameter. -
FIG. 10 is a graph showing the relationship between a high pressure of a pressure controlling valve and COP in a refrigeration cycle not having an internal heat exchanger by using a refrigerant temperature as a parameter. -
FIG. 11 is a graph showing a line of a controlpressure change width 2 MPa at a refrigerant temperature of 40° C. by plotting a gas sealing density to the abscissa. -
FIG. 12 is a graph showing a line of a controlpressure change width 2 MPa at a refrigerant temperature of 60° C. by plotting a gas sealing density to the abscissa. -
FIGS. 13A and 13B are explanatory views useful for explaining a valve closure state and a valve open state of a pressure controlling valve. -
FIG. 14 is a sectional view of a pressure controlling valve according to the prior art. - The pressure controlling valves according to embodiments of the present invention will be hereinafter explained with reference to the drawings.
FIG. 1 is an explanatory view explaining a refrigeration cycle (supercritical refrigeration cycle) into which an internal heat exchanger is assembled, and which circulates CO2 as a refrigerant.FIG. 2 shows a pressure controlling valve according to the first embodiment of the present invention that is applied to the refrigeration cycle shown inFIG. 1 . InFIG. 1 ,reference numeral 1 denotes a compressor that sucks in and compresses a CO2 refrigerant andreference numeral 2 denotes a gas cooler (heat radiator) that cools the refrigerant compressed by thecompressor 1. -
Reference numeral 3 denotes a pressure controlling valve (expansion valve) according to this embodiment. Thispressure controlling valve 3 has a temperature sensitive portion (sealed space) A into which CO2 gas is sealed, and controls refrigerant pressure on the exit side of thegas cooler 2 on the basis of the refrigerant temperature on the exit side of thegas cooler 2. Therefore, the pressure controlling valve operates also as a pressure reducing device that reduces the pressure of the high pressure refrigerant. Thepressure controlling valve 3 has a valve function for opening and closing a refrigerant passage extending from thegas cooler 2 to theinternal heat exchanger 6 and a refrigerant passage extending from theinternal heat exchanger 6 to anevaporator 4. Thepressure controlling valve 3 will be explained later in further detail. - The
evaporator 4 evaporates a gas-liquid two-phase refrigerant the pressure of which is reduced by thepressure controlling valve 3, and cools air passing outside theevaporator 4.Reference numeral 5 denotes an accumulator that separates the gaseous refrigerant from the liquid phase refrigerant and temporarily stores excess refrigerant inside the refrigeration cycle.Reference numeral 6 denotes the internal heat exchanger that is arranged inside the refrigeration cycle so that refrigerant that flows from thegas cooler 2 to thepressure controlling valve 3 and the refrigerant flowing from theaccumulator 5 to thecompressor 1 conduct heat-exchange with each other. Thecompressor 1, thegas cooler 2, thepressure controlling valve 3, theevaporator 4, theaccumulator 5 and theinternal heat exchanger 6 are connected to one another through piping and constitute a closed circuit. Therefore, CO2 refrigerant discharged from thecompressor 1 is taken into theoriginal compressor 1 through thegas cooler 2→internal heat exchanger 6→pressure controlling valve 3→evaporator 4→accumulator 5→internal heat exchanger 6. - Next, the
pressure controlling valve 3A of the first embodiment used for the refrigeration cycle shown inFIG. 1 will be explained with reference toFIG. 2 . A first flow passage F1 as a part of the refrigerant flow passage extending from thegas cooler 2 to theinternal heat exchanger 6 and a second flow passage F2 as a part of the refrigerant flow passage extending from theinternal heat exchanger 6 to theevaporator 4 through avalve port 33 g are independently formed inside abody 33 of thepressure controlling valve 3A. To install the pressure sensitive portion (sealed space) later described, afirst opening 33 e is arranged on the heat sensitive portion and asecond opening 33 f for setting anadjustment spring 36 is arranged at a lower part besides an inflow port 33 a connected to the gas cooler (2) side and anoutflow port 33 b connected to the internal hat exchanger side that together constitute the first flow passage F1 and aninflow port 33 c connected to the internal heat exchanger (6) side and anoutflow port 33 d connected to the evaporator (4) side that together constitute the second flow passage F2. - A
displacement transmission member 31 having avalve portion 31 a formed at its distal end is accommodated in thebody 33 and thevalve portion 31 a of thedisplacement transmission member 31 opens and closes avalve port 33 g. Consequently, the second flow passage F2 is opened and closed and theinternal heat exchanger 6 and theevaporator 4 are communicated with, and cut off from, each other. - A temperature sensitive portion is fitted to a
first opening 33 e of thebody 33. The temperature sensitive portion includes aresilient member 32, such as a diaphragm or bellows, acover member 35, alower support member 34, and a sealed space A is formed inside the temperature sensitive portion. In other words, arecess 35 a for forming the sealed space A is formed at the center of thecover member 35 and the peripheral edge of theresilient member 32 is clamped and fixed by thecover material 35 and thelower support member 34 to form the temperature sensitive portion. Theresilient member 32 has a thin film made of stainless steel and undergoes deformation and displacement in accordance with the pressure difference between the inside and the outside of the sealed space A. Thelower support member 34 has acylindrical portion 34 a and aflange portion 34 b, and a screw portion formed around the outer circumference of thecylindrical portion 34 a is mated with thefirst opening 33 e of thebody 33, thereby fixing the temperature sensitive portion to thebody 33. A fillingpipe 35 b is fitted to thecover member 35 and a gas, such as CO2 is sealed from the fillingpipe 35 b into the sealed space A. The fillingpipe 35 b is closed after the gas is sealed. - One of the
end portions 31 b of thedisplacement transmission member 31 that extends upward from thevalve portion 31 a through thecylindrical portion 34 a of thelower support member 34 is fixed to theresilient member 32 and a clearance B having an annular sectional shape is defined between the inner surface of thecylindrical portion 34 a and the outer peripheral surface of thedisplacement transmission member 31. This clearance B communicates with the first flow passage F1 connected to the exit side of thegas cooler 2. As a result, the refrigerant on the exit side of thegas cooler 2 flows into the clearance B and the refrigerant temperature is transmitted to the gas inside the sealed space A. At the same time, the pressure of the refrigerant on the exit side of thegas cooler 2 operates on theresilient member 32. - A cavity (space A1) 31 d communicating with the sealed space A of the temperature sensitive portion is formed at an
end portion 31 b of thedisplacement transmission member 31. To communicate the cavity 31 d with the sealed space A in this case, a through-hole 32 a is naturally formed in theresilient member 32, and the sealed space A and the cavity (space A1) 31 d communicate with each other through this through-hole 32 a. According to this construction, the sealed space of the temperature sensitive portion can be set to the sum of the sealed space A+space A1 and the sealed space can be expanded, so that accuracy of the temperature sensitive portion can be improved. - An
adjustment nut 37 meshes with theother end portion 31 c of thedisplacement transmission member 31 extending downward below thevalve portion 31 a through thevalve port 33 g. Anadjustment spring 36 for forcing thevalve portion 31 a of thedisplacement transmission member 31 in the closing direction of the valve is interposed between the lower surface of thevalve port 33 g and theadjustment nut 37. An initial set load of the adjustment spring 36 (elastic force under the closure state of thevalve port 33 g) can be arbitrarily adjusted by turning theadjustment nut 37. Theadjustment spring 36,adjustment nut 37, and so forth, are disposed inside adownstream space 37 as a part of the second flow passage F2 connected to the entry side of theevaporator 4. When thecap 38 is fitted into thesecond opening 33 f of thebody 33, the lower part of the downstream space C is closed. - In the
pressure controlling valve 3A of the first embodiment having the construction described above, the valve closing force of thedisplacement transmission member 31 is acquired by the internal pressure inside the sealed space (A+A1) and theadjustment spring 36, and the valve opening force of thedisplacement transmission member 31 is acquired by the refrigerant pressure on the exist side of thegas cooler 2. Thepressure controlling valve 3A is opened and closed in accordance with the balance of both of the valve opening and closing forces. The internal pressure of the sealed space (A+A1) changes depending on the refrigerant temperature on the exit side of thegas cooler 2 flowing into the clearance B, and as the opening of thevalve port 33 g thus changes, the refrigerant pressure on the exist side of theinternal heat exchanger 6 is controlled. - It is known that in a refrigeration cycle using CO2 as the refrigerant, there is high pressure at which COP (performance coefficient) reaches a maximum. The use of an
internal heat exchanger 6 for effecting heat exchange between the refrigerant at the exit of thegas cooler 2 and the taken-in refrigerant of thecompressor 1 has been proposed as a means for improving COP. -
FIG. 9 is a graph showing the relationship between the high pressure and COP by plotting the cases of the outlet refrigerant temperature of 40° C., 50° C. and 60° C. when theinternal heat exchanger 6 is used, the temperature of theevaporator 4 is 20° C. and the superheat quantity (the degree of superheat) of the taken-in refrigerant of thecompressor 1 is 20° C., respectively. - The pressure controlling valve 3 (3A) used for the cycle of the CO2 refrigerant regulates the high pressure of the cycle to the pressure at which COP becomes maximal with respect to the exit refrigerant temperature of the
gas cooler 2. Therefore, the pressure controlling characteristics are regulated by the sealed gas density, etc, of the heat sensitive portion (sealed space) of the pressure controlling valve 3 (3A) so as to achieve the temperature-pressure characteristics indicated by a dashed line inFIG. 9 . - The CO2 gas or a mixture of the CO2 gas and a small amount of an inert gas, such as nitrogen gas is sealed into the temperature sensitive portion (sealed space) of the pressure controlling valve 3 (3A). Since the CO2 gas reaches a supercritical state at a temperature of about 31° C. or above, the volume of the sealed space A or (A+A1) into which the gas is sealed changes, with the displacement of the
resilient member 32, such as the diaphragm or the bellows, so that the pressure inside the sealed space changes even though the exit refrigerant temperature of thegas cooler 2 does not change. - The
pressure controlling valve 3 opens and closes the valve in accordance with the displacement of theresilient member 32. Therefore, when the valve is open as shown inFIG. 13A , theresilient member 32 deforms to a convex state in the down direction, but when the flow rate of the refrigerant increases and the valve lift quantity becomes great, theresilient member 32 undergoes displacement upward and the volume of the sealed space of the temperature sensitive portion becomes small. The sealing density of the gas increases and the pressure rises, too. Consequently, the control pressure increases when the opening of thepressure controlling valve 3 increases as shown inFIG. 13B . - The drop of COP relative to the control pressure is preferably as small as possible. To reduce the volume change with respect to the valve opening of the
pressure controlling valve 3, the sealed space into which the gas is sealed must be increased. In this embodiment, therefore, the sealed spaces A, A+A1 are increased by forming therecess portion 35 a on thecover member 35 and/or forming the cavity portion 31 d in thedisplacement transmission member 31. -
FIGS. 7 and 8 represent the degree of the change of the control pressure when the valve changes from the full closure state to full open state with respect to the volume ratio of the sealed space at the refrigerant temperatures of 40° C. and 60° C., respectively, by using the sealed gas density as a parameter. - The volume ratio is defined by Vs/(Vs−Vo) where Vs is the total volume of the sealed space at the time of closing of the valve and Vo is the total volume of the sealed space at the time of opening of the valve.
- In other words, the volume ratio represents how many times of volume (Vs) of the volume change quantity (Vs−Vo) owing to opening/closing of the valve is necessary relative to the change of the control pressure.
-
FIG. 7 shows the necessary volume ratio at a refrigerant temperature of 40° C. The volume ratio rapidly increases from a pressure change of not greater than 1 MPa at a relatively low sealing density (300 kg/m3) used as thepressure controlling valve 3 though the value changes dependent on the sealed gas density. In the case of a relatively high sealing density (600 kg/m3), on the other hand, the volume ratio rapidly increases from the pressure change of below 2 MPa and the necessary volume of the sealed space becomes great. Incidentally, the sealing density represents the density with respect to the volume of the sealed space at the closure of the valve. - Similarly, at a refrigerant temperature of 60° C. as shown in
FIG. 8 , the volume ratio rapidly increases from below 2 MPa in the case of the sealing density of 300 kg/m3, and rapidly increases from below 4 MPa in the case of the sealing density of 600 kg/m3, and the necessary volume of the sealed becomes great. - It can be understood from above that in order to make the temperature sensitive portion of the
pressure controlling valve 3 compact, the change of the control pressure is preferably 1 to 2 MPa when the refrigerant temperature is 40° C. and 2 to 4 MPa at the refrigerant temperature of 60° C. - Next, the COP change of the cycle with respect to the control pressure will be explained as shown in
FIG. 9 . The pressure change width at the COP drop ratio of 10% is 3 MPa at the refrigerant temperature of 40° C., 4.2 MPa at the refrigerant temperature of 50° C. and 6.7 MPa at the refrigerant temperature of 60° C. The same COP drop ratio is scored with a pressure change width of at least twice at the refrigerant temperatures of 50° C. and 60° C. with respect to the pressure change width at the refrigerant temperature of 40° C. - When the volume ratio is constant, the change width of the control pressure at the refrigerant temperature of 60° C. is about twice the change width at a refrigerant temperature of 40° C., but an equal level of the COP drop ratio of the cycle can be obtained.
-
FIG. 10 shows the COP change of the cycle with respect to the control pressure when theinternal heat exchanger 6 is not used. Because the pressure change width at the same COP drop ratio is greater than when theinternal heat exchanger 6 shown inFIG. 9 is used, COP does not greatly drop even when thepressure controlling valve 3 of this embodiment is used in the case where theinternal heat exchanger 6 is not used. -
FIG. 11 is a graph showing the relationship between the volume ratio of the sealed space at the refrigerant temperature of 40° C. inFIG. 7 and the change quantity of the control pressure when the valve changes from the full closure to the full open state with the sealed gas density as a parameter. The abscissa represents the sealing density and the ordinate does the volume ratio. The graph shows the line of the controlpressure change width 2 MPa at the refrigerant temperature of 40° C. - It can be understood from above that in order to make small the temperature sensitive portion (sealed space) of the
pressure controlling valve 3 and to minimize the change of the control pressure, it is necessary to employ the following measures: - (1) at least the volume ratio is set to 1.9 or more (at the gas sealing density of 300 kg/m3); and
- (2) the volume ratio is made greater than the solid line in
FIG. 11 with respect to the gas sealing density. - In the refrigeration cycle of the CO2 refrigerant, the optimal high pressure (the pressure at which COP becomes maximal) rises, too, when the refrigerant temperature at the exit of the
gas cooler 2 rises. When the high pressure becomes higher, however, the problems occur in that durability of the apparatus drops and the discharge temperature of thecompressor 1 rises. For this reason, a pressure of about 15 MPa is set in many cases as the upper limit value of the high pressure. - When the
internal heat exchanger 6 is used as shown inFIG. 9 , the optimal high pressure is about 14 MPa when the refrigerant temperature is 60° C. and often exceeds the upper limit value of 15 MPa if the change of the control pressure is large. - The COP change with respect to the control pressure is small when the refrigerant temperature is 60° C. as shown in
FIG. 9 . When the lower limit value of the control pressure is set to 12 MPa, therefore, a margin width of about 3 MPa can be acquired with respect to the upper limit value. -
FIG. 12 is a graph showing the relation between the volume ratio of the sealed space at the refrigerant temperature of 60° C. inFIG. 8 and the change quantity of the control pressure when the valve changes from the full closure to the full open with the sealed gas density as a parameter. The abscissa represents the sealing density and the ordinate does the volume ratio. The graph shows the line of the controlpressure change width 3 MPa at the refrigerant temperature of 60° C. - It can be understood that to make small the sealed space as the gas sealing portion of the
pressure controlling valve 3 and to prevent the control pressure from exceeding the upper limit value (15 MPa), the following may well be employed: - (1) at least the volume ratio is set to 2.4 or more (at the gas sealing density of 300 kg/m3); or
- (2) the volume ratio is made greater than the solid line in
FIG. 12 with respect to the gas sealing density; and - (3) the pressure at which the pressure controlling valve opens is set to a pressure lower than the optimal high pressure (14 MPa).
- The optimal high pressure is about 9.5 MPa at the refrigerant temperature of 40° C. and has a margin to the upper limit pressure. Since the COP change with respect to the control pressure drastically drops below the optimal high pressure, a large COP change can be prevented even when the control pressure exhibits some variance when the pressure at the opening of the
pressure controlling valve 3 is the optimal high pressure. -
FIG. 3 is an explanatory view useful for explaining the refrigeration cycle of the CO2 refrigerant without incorporating the internal heat exchanger.FIG. 4 shows apressure controlling valve 3B according to the second embodiment of the invention that is applied to the refrigeration cycle shown inFIG. 3 . The same reference numeral is used to identify the same constituent member as inFIG. 1 . In other words,reference numeral 1 denotes the compressor for sucking and compressing the CO2 refrigerant.Reference numeral 2 denotes the gas cooler for cooling the refrigerant compressed by thecompressor 1. The pressure controlling valve 3 (3B) for controlling the refrigerant pressure on the exit side of thegas cooler 2 on the basis of the refrigerant temperature on the exit side of thegas cooler 2 is arranged on the exit side of thegas cooler 2 and operates as a pressure reducing device for reducing the pressure of the high pressure refrigerant. -
Reference numeral 4 denotes the evaporator for evaporating the gas-liquid two-phase refrigerant the pressure of which is reduced by thepressure controlling valve 3.Reference numeral 5 denotes the accumulator for separating the gaseous phase refrigerant from the liquid phase refrigerant and temporarily storing the excess refrigerant inside the refrigeration cycle. Thecompressor 1, thegas cooler 2, thepressure controlling valve 3, theevaporator 4 and theaccumulator 5 are connected to one another through piping and form a closed circuit. - The
pressure controlling valve 3B according to the second embodiment of the invention and shown inFIG. 3 is used in the cycle not using the internal heat exchanger. Therefore, only a flow passage F as a part of the refrigerant flow passage extending from thegas cooler 2 to theevaporator 4 through thevalve port 33 g is formed inside thebody 33 of thepressure controlling valve 3B. Thesecond opening 33 f of thebody 33 of thepressure controlling valve 3B is closed, and the extension portion below thevalve portion 31 a of thedisplacement transmission member 31, theadjustment spring 36 and theadjustment nut 37 are omitted. Furthermore, the cavity 31 d formed at one of theends 31 b of thedisplacement transmission member 31 is omitted. Accordingly, the sealed space A is formed by therecess portion 35 a disposed in thecover member 35. The rest of the constructions are the same as those of the first embodiment and the explanation will be omitted. - Only the internal pressure by the gas sealed into the sealed space A, into which the refrigerant temperature on the exit side of the
gas cooler 2 flowing into the clearance B is transmitted, operates as the valve closing force of thedisplacement transmission member 31 in the second embodiment, and the refrigerant pressure on the exit side of thegas cooler 2 operates as the valve opening force. In this case, the gas sealed into the sealed space A also performs the function of theadjustment spring 36. Here, the CO2 gas that changes the internal pressure in accordance with the temperature and a small amount of an inert gas, such as a nitrogen gas that generates an internal pressure of a substantially constant level without changing the internal pressure in accordance with the temperature within the temperature range of the detection object are mixed and sealed. - In the second embodiment, the
recess portion 35 a of thecover member 35 of theresilient member 32 is made as large as possible to secure the volume ratio by increasing the volume of the sealed space A as the temperature sensitive portion. -
FIGS. 5A and 5B are schematic views of the refrigeration cycles of the CO2 refrigerant in the case where thepressure controlling valve 3C according to the third embodiment is used, but theinternal heat exchanger 6 is not used and in the case where theinternal heat exchanger 6 is used, respectively.FIG. 6 shows thepressure controlling valve 3C according to the third embodiment of the invention. The arrangement of the constituent elements in the schematic view of the refrigeration cycle shown inFIG. 5A is basically the same as that of the refrigeration cycle shown inFIG. 3 with the exception of the construction of thepressure controlling valve 3. The schematic view of the refrigeration cycle inFIG. 5B is basically the same as the refrigeration cycle shown inFIG. 1 and the explanation will be therefore omitted. In other words, thepressure controlling valve 3 shown inFIGS. 5A and 5B has acapillary tube 7 connected to the sealed space A as the heat sensitive portion and a temperaturesensitive cylinder 8 arranged at the distal end of thecapillary tube 7. This temperaturesensitive cylinder 8 is disposed to keep contact with the exit piping of thegas cooler 2. - In the
pressure controlling valve 3C according to the third embodiment of the present invention, only one flow passage F is formed inside thebody 33. This flow passage F is used as a part of the refrigerant flow passage extending from thegas cooler 2 to theevaporator 4 through thevalve port 33 g when thepressure controlling valve 3C is used for the cycle not having theinternal heat exchanger 6 shown inFIG. 5A and when used for the cycle using theinternal heat exchanger 6 shown inFIG. 5B , the flow passage F is used as a part of the refrigerant flow passage extending from theinternal heat exchanger 6 to theevaporator 4 through thevalve port 33 g. The cavity 31 d is not formed at one of the ends of thedisplacement transmission member 31. Instead, thecapillary tube 7 having the temperaturesensitive cylinder 8 at its distal end is fitted as a member communication with the sealed space A to thecover member 35 and the inside of thecapillary tube 7 is connected with the sealed space A. Therefore, the volume of the sealed space into which the gas is sealed can be increased. The rest of the constructions are the same as those of thepressure controlling valve 3A of the first embodiment. - In the
pressure controlling valve 3C according to this third embodiment, the valve closing force and the valve opening force of thedisplacement transmission member 31 operates in the same way as those of thepressure controlling valve 3A of the first embodiment, but the sealed gas inside the sealed space mainly receives the thermal influences from the heatsensitive cylinder 8 arranged at the exit piping of thegas cooler 2. - Incidentally, the present invention has been described in detail on the basis of the specific embodiments thereof, but can be changed or modified in various ways by those skilled in the art without departing from the scope and spirit of the invention.
Claims (16)
Vs/(Vs−Vo)≧1.9.
Vs/(Vs−Vo)≧2.4.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2006-192897 | 2006-07-13 | ||
JP2006192897A JP2008020141A (en) | 2006-07-13 | 2006-07-13 | Pressure control valve |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080011363A1 true US20080011363A1 (en) | 2008-01-17 |
Family
ID=38922280
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/827,095 Abandoned US20080011363A1 (en) | 2006-07-13 | 2007-07-10 | Pressure Control Valve |
Country Status (4)
Country | Link |
---|---|
US (1) | US20080011363A1 (en) |
JP (1) | JP2008020141A (en) |
CN (1) | CN101105355A (en) |
DE (1) | DE102007032254A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2848878A3 (en) * | 2008-03-31 | 2015-05-20 | Fujikoki Corporation | Pressure Control Valve |
US20150195049A1 (en) * | 2012-02-29 | 2015-07-09 | Verifone, Inc. | Point of sale device and method for operating same |
US20160236534A1 (en) * | 2013-10-14 | 2016-08-18 | Weidplas Gmbh | Motor vehicle having an air-conditioning system |
DE112012005909B4 (en) | 2012-02-20 | 2021-11-04 | Denso Corporation | Expansion valve |
US11460124B2 (en) * | 2019-03-15 | 2022-10-04 | Carrier Corporation | Ejector and refrigerating system |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5250446B2 (en) * | 2009-02-16 | 2013-07-31 | 株式会社不二工機 | Temperature expansion valve |
JP5620833B2 (en) * | 2011-01-24 | 2014-11-05 | 株式会社不二工機 | 3-way solenoid valve |
CN102368008A (en) * | 2011-07-17 | 2012-03-07 | 太平洋电子(昆山)有限公司 | Expansion valve |
KR20230021760A (en) | 2016-08-16 | 2023-02-14 | 피셔 앤 페이켈 핼스케어 리미티드 | Pressure regulating valve |
JP7182283B2 (en) * | 2019-11-25 | 2022-12-02 | 株式会社不二工機 | Power element and expansion valve using the same |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5228619A (en) * | 1992-05-15 | 1993-07-20 | Fuji Koki Manufacturing Co., Ltd. | Thermal expansion valve |
US5269459A (en) * | 1991-10-17 | 1993-12-14 | Eaton Corporation | Thermally responsive expansion valve |
US5890370A (en) * | 1996-01-25 | 1999-04-06 | Denso Corporation | Refrigerating system with pressure control valve |
US6056202A (en) * | 1996-09-12 | 2000-05-02 | Fujikoki Corporation | Expansion valve |
US6189326B1 (en) * | 1998-07-07 | 2001-02-20 | Denso Corporation | Pressure control valve |
US20030183702A1 (en) * | 1999-07-19 | 2003-10-02 | Masamichi Yano | Method for preventing hunting of expansion valve within refrigeration cycle |
US20060150650A1 (en) * | 2005-01-13 | 2006-07-13 | Denso Corporation | Expansion valve for refrigerating cycle |
-
2006
- 2006-07-13 JP JP2006192897A patent/JP2008020141A/en active Pending
-
2007
- 2007-07-10 US US11/827,095 patent/US20080011363A1/en not_active Abandoned
- 2007-07-11 DE DE200710032254 patent/DE102007032254A1/en not_active Withdrawn
- 2007-07-13 CN CNA2007101368608A patent/CN101105355A/en active Pending
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5269459A (en) * | 1991-10-17 | 1993-12-14 | Eaton Corporation | Thermally responsive expansion valve |
US5228619A (en) * | 1992-05-15 | 1993-07-20 | Fuji Koki Manufacturing Co., Ltd. | Thermal expansion valve |
US5890370A (en) * | 1996-01-25 | 1999-04-06 | Denso Corporation | Refrigerating system with pressure control valve |
US6056202A (en) * | 1996-09-12 | 2000-05-02 | Fujikoki Corporation | Expansion valve |
US6189326B1 (en) * | 1998-07-07 | 2001-02-20 | Denso Corporation | Pressure control valve |
US20030183702A1 (en) * | 1999-07-19 | 2003-10-02 | Masamichi Yano | Method for preventing hunting of expansion valve within refrigeration cycle |
US20060150650A1 (en) * | 2005-01-13 | 2006-07-13 | Denso Corporation | Expansion valve for refrigerating cycle |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2848878A3 (en) * | 2008-03-31 | 2015-05-20 | Fujikoki Corporation | Pressure Control Valve |
DE112012005909B4 (en) | 2012-02-20 | 2021-11-04 | Denso Corporation | Expansion valve |
US20150195049A1 (en) * | 2012-02-29 | 2015-07-09 | Verifone, Inc. | Point of sale device and method for operating same |
US20160236534A1 (en) * | 2013-10-14 | 2016-08-18 | Weidplas Gmbh | Motor vehicle having an air-conditioning system |
US11460124B2 (en) * | 2019-03-15 | 2022-10-04 | Carrier Corporation | Ejector and refrigerating system |
Also Published As
Publication number | Publication date |
---|---|
DE102007032254A1 (en) | 2008-02-14 |
JP2008020141A (en) | 2008-01-31 |
CN101105355A (en) | 2008-01-16 |
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