Refrigeration – Gas compression – heat regeneration and expansion – e.g.,...
Reexamination Certificate
2002-07-17
2003-04-15
Doerrler, William C. (Department: 3744)
Refrigeration
Gas compression, heat regeneration and expansion, e.g.,...
C060S520000, C074S018000
Reexamination Certificate
active
06546738
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the priority benefit of Japanese application serial no. 2001-223585 filed on Jul. 24, 2001, 2001-223586 filed on Jul. 24, 2001, 2001-223587 filed on Jul. 24, 2001, 2001-223588 filed on Jul. 24, 2001, 2001-223589 filed on Jul. 24, 2001 and 2001-223590, filed on Jul. 24, 2001.
BACKGROUND OF INVENTION
1. Field of the Invention
This invention relates to a Stirling refrigerator.
2. Description of Related Art
In recent years, a Stirling refrigerator has been suggested as a refrigerating device using a substitute for environmentally problematic Freon, or as a refrigerator whose operation temperature is in a broader range than that of a conventional cooling device. This refrigerator can be applied to the apparatuses utilizing cooling heat for business or household use as a freezer, a refrigerator, and a throw-in type cooler, and the cooling heat utilizing apparatuses of all industrial fields such as a low-temperature fluid circulator, a low-temperature isothermal unit, an isothermal tank, a heat shock test device, a freezing drier, a thermal property test device, a blood/cell storage-devices, a cold cooler, and other various cooling heat devices. Furthermore, this refrigerator is compact, high in coefficient of performance, and excellent in energy efficiency.
In a heat engine of the Stirling refrigerator, working gas is sealed into a housing of the machine in a sealed condition, wherein the housing forms the body of the machine, and has a crank chamber and a motor chamber. The working gas flows through a flow passage between a compression chamber (high-temperature chamber) and an expansion chamber (low-temperature chamber). A radiating heat exchanger (at high-temperature side), a regenerator and a cooling heat exchange (at low-temperature side) are disposed along the flow passage of the working gas. A cooling heat refrigerant and a radiating refrigerant are respectively heat-exchanged by the radiating and cooling heat exchangers, and a heat exchanging performance is enhanced by radiating and absorbing of heat.
The working gas is expended or compressed by expansion or compression piston through driving devices such as connecting rods that are disposed on a crank shaft driven by a motor. A shock-resistant balancer is disposed on the crank shaft.
A coupler for injecting the working gas is set in a crank chamber and a buffer chamber (a back space of the piston inside the compression or the expansion cylinder) of a Stirling refrigerator such as Stirling heat engine. The coupler can link the source of the working gas in order to inject the working gas.
A pressure sensor, which also functions as a pressure adjuster, is detachably installed on an installing block through a pressure sensor fitment (referring to the prior art example in FIG.
7
B).
The Stirling refrigerator has a problem, which is so-called oil rising, that oil or oil mist rises from a crank chamber along the piston rods. Regarding the oil rising, as the oil or oil mist enters the cylinders, the oil or oil mist adheres to the inner surfaces of the cylinder effecting the sealing performance of the piston rings. Not only the durability and the reliability of the refrigerator are obviously decreased, but also the compressed gas and oil enter the compression gas utilizing apparatuses, so that the compression gas utilizing apparatuses or parts treated by compression gas utilizing apparatuses is deteriorated.
For solving the oil rising problem, the conventional piston rod is sealed by an oil ring seal. The oil ring seals are generally made of gum and have been developed using various structures and materials, but they are not necessarily sufficient in sealing performance or durability.
Therefore, inventors have proposed an oil seal bellows (referring to Japanese Patent application 10-365371) as a rod seal (piston rod seal) of a Stirling refrigerator. In the invention of 10-365371, an oil seal metal bellows is set between a housing of the Stirling refrigerator and the compression and expansion cylinders, preventing the oil rising from entering the compression cylinder and the expansion cylinder from the crank chamber along the surface of the piston rods.
The balancer installed on the crank shaft is generally fixed by screws onto an installing surface formed on the crank shaft (a flat surface mostly). However, the balancer moves (rotates) centered on the screws with respect to the crank shaft during operation and therefore the installing portion drifts, so that the shock-resistant performance is reduced.
Although the coupler for injecting working gas is separated from the Stirling refrigerator, it is still affected by the vibration due to the operation of the Stirling refrigerator, so that the fixing screws of the coupler loosen and thus the working gas leaks.
In the Stirling refrigerator, the oil seals are used to seal the cylinders (compression, and expansion cylinders) in order to prevent the oil from entering the cylinder along the piston rod from the crank chamber during operation. However, as the pressure difference of working gas between the crank chamber and cylinders is created, problems of oil seals being imperfect or broken occur.
It is needed to regularly check the working gas pressure in the crank chamber to inject the working gas through the coupler, to adjust flare nuts attached to the pressure sensor, or to adjust the working gas pressure. However, because the flare nuts are buried inside the pressure sensor fitment and are not easy to approach (referring to prior art in FIG.
7
B), it is not easy to adjust working gas during the maintenance, such as the regular check of the fix etc.
Inventors developed the above oil seal bellows installed in the Stirling refrigerator to further increase the life time of the oil seal bellows. However, this has become not preferable due to fatigue generated when they repeat moving back and forth in a predetermined stroke in a compression and a expansion directions.
The regenerator is generally formed by filling with tiny wire-netting material. The inferior quality of the wire-netting material, which turns bad when time goes by, will be cut into pieces and flow with working gas into the heat exchangers, high-temperature chamber, low-temperature chamber, etc., so that the flowing resistance of working gas increases and the smooth activity of the piston is frustrated, causing the performance to be deteriorated and damaged.
The space of the cylinders forming the high-temperature chamber or the low-temperature chamber and the space between housings are sealed by the rod seals, such as the oil seal bellows, so that the oil doesn't flow from the crank chamber of the housing into the space of the cylinders. However, if a pressure difference of working gas exists between the space of cylinders and inside of the housing, it burdens the rod seal, makes the performance decrease and causes breaking. The pressure in the space of the cylinders is not stable, the performance of the heat engine is therefore not stable.
Because the housing is generally formed by casting and the working gas filled into the housing has a small molecular weight, such as helium or the like, it should be noted that the gas leaks from the thin part of the casting.
Especially, when some accessories, such as terminal box are fixed to the thin part of the housing by screws, the thickness is relatively thin in the region of screw hole so that the working gas leaks form the relatively thin part to the outside. The working gas pressure inside the housing therefore decreases, and the performance, the durability of the rod seal and performance of heat engine worsens.
SUMMARY OF INVENTION
According to the foregoing description, an object of this invention is to provide a Stirling refrigerator preventing the installing position moving with respect to the crank shaft, and the balancer can be fixed onto the crank shaft without moving in order to improve the shock-resistant function.
Another object of the prevent invention is to provide a balancer, which prevents loosenes
Fukuda Eiji
Inoue Takashi
Kanai Hiroshi
Komatsubara Takeo
Mashimo Denji
Doerrler William C.
Jiang Chyun IP Group
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