STIRLING SYSTEM AND FREEZER SYSTEM USING THE SAME

Abstract

There is disclosed a stirling system in which a rotary-type high-temperature expansion mechanical section, a rotary-type low-temperature compression mechanical section and a driving shaft common to both the mechanical sections are stored in a sealed container to achieve remarkable simplification and improvement of durability. In the stirling system, the rotary-type high-temperature expansion mechanical section and the rotary-type low-temperature compression mechanical section for constituting a stirling cycle, and the driving shaft common to both the mechanical sections are stored in the sealed container. The sealed container is divided into a rotary-type high-temperature expansion mechanical section side and a rotary-type low-temperature compression mechanical section side by a partition wall.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a stirling system in which a rotary-type rotary-type high-temperature expansion mechanical section and a rotary-type low-temperature compression mechanical section for constituting a stirling cycle are stored in a sealed container, and a freezer system using the stirling system.

2. Description of the Background Art

Heretofore, a stirling engine (a stirling cycle) as an external combustion engine is provided with a displacer piston which reciprocates in a cylinder as one example. Moreover, a high-pressure operation gas with which the cylinder is filled is reciprocated between a heating section to be heated by a heating source such as a combustion gas and a cooling section to be cooled by a cold source using cooling water. In consequence, a pressure difference of the operation gas is created in the cylinder, and this pressure difference is taken out as motive energy via a power piston which cooperates with the displacer piston with a phase of 90 degrees. Such a constitution has been proposed (see Japanese Patent Application Laid-Open No. 2006-275018).

Such a stirling system having a piston system (reciprocating type) mechanism is a mainstream, and simplification of a stirling system including a rotary mechanism (a rotary system) has been investigated. As one example of this simplification, application of a Wankel type mechanism has scientifically been investigated.

However, unlike a presently mainstream internal combustion engine, the stirling system has excellent characteristics such as high efficiency, variety of fuel and heat source, quietness and cleanness of exhaust. However, since the former stirling system receives heat from the outside, internally performs heat exchange and uses the high-pressure operation gas, the whole mechanism tends to be complicated and increase a weight thereof. There is much room for improvement even in durability and response, and the system is expensive and lacks in market competitiveness. Therefore, the simplification and cost reduction of the stirling system have been demanded.

Moreover, a driving section of the latter Wankel type mechanism is simplified from a crank mechanism to a rotary mechanism, but characteristics such as an operation capacity of an essential fluid operation mechanism are not adapted, a structure is not integrated, the system is complicated even as a thermal system, and hence the system has not been put to practical use.

The present invention has been developed to solve such problems of the conventional technologies, and an object thereof is to provide a stirling system in which a rotary-type high-temperature expansion mechanical section, a rotary-type low-temperature compression mechanical section and a driving shaft common to both the mechanical sections are stored in a sealed container to achieve remarkable simplification and improvement of durability, and a freezer system using the stirling system.

SUMMARY OF THE INVENTION

A stirling system of a first invention is characterized in that a rotary-type high-temperature expansion mechanical section and a rotary-type low-temperature compression mechanical section which constitute a stirling cycle, and a driving shaft common to both the mechanical sections are stored in a sealed container and that the sealed container is divided into a rotary-type high-temperature expansion mechanical section side and a rotary-type low-temperature compression mechanical section side by a partition wall.

Moreover, a stirling system of a second invention is characterized in that in the above invention, a control mechanism which controls a performance characteristic of the stirling cycle, and a generator or a motor are directly connected to the driving shaft on the rotary-type low-temperature compression mechanical section side in the sealed container.

Furthermore, a stirling system of a third invention is characterized in that in the first or second invention, a heater, a cooler and a regenerative heat exchanger which constitute the stirling cycle are integrated with the sealed container inside or outside the sealed container.

In addition, a stirling system of a fourth invention is characterized in that any one of the first to third inventions further comprises: a press feed mechanism of a lubricant which lubricates sliding sections in the sealed container; and a return mechanism which separates the lubricant from an operation gas discharged from the sealed container to return the lubricant into the sealed container.

Moreover, a freezer system of a fifth invention is characterized by comprising a motor which drives a driving shaft and operating a stirling cycle of the stirling system according to any one of the first to fourth inventions in a reverse cycle.

According to the first invention, the rotary-type high-temperature expansion mechanical section and the rotary-type low-temperature compression mechanical section which constitute the stirling cycle, and the driving shaft common to both the mechanical sections are stored in the sealed container, and the sealed container is divided into the rotary-type high-temperature expansion mechanical section side and the rotary-type low-temperature compression mechanical section side by the partition wall. Therefore, in a case where the control mechanism which controls the performance characteristic of the stirling cycle, and the generator or the motor are directly connected to the driving shaft on the rotary-type low-temperature compression mechanical section side in the sealed container, response of power transmission can remarkably be improved. Since the rotary-type high-temperature expansion mechanical section and the rotary-type low-temperature compression mechanical section are stored in the sealed container, the control mechanism and the generator or the motor are not directly impacted from the outside, and can avoid wind and rain. In consequence, it can securely be prevented that the control mechanism and the generator and the motor are corroded by damages, wind and rain, and hence durability of the stirling system can largely be improved.

Especially, since the rotary-type high-temperature expansion mechanical section and the rotary-type low-temperature compression mechanical section are stored in the sealed container, remarkable simplification and durability of the stirling system can be secured. In consequence, since the compact stirling system can be realized, a weight of the system can largely be reduced as compared with, for example, the conventional stirling system. Therefore, productivity can remarkably be improved, costs can largely be reduced, and market competitiveness of the stirling system can generally largely be improved.

Moreover, according to the third invention, in addition to the first or second invention, the heater, the cooler and the regenerative heat exchanger which constitute the stirling cycle are integrated with the sealed container inside or outside the sealed container, so that the stirling system can easily be conveyed anywhere and installed anywhere. In consequence, a conveying property, an installing property and the like of the stirling system can largely be improved, and versatility of the stirling system can remarkably be improved.

Furthermore, according to the fourth invention, in addition to any one of the first to third inventions, since the system further comprises the press feed mechanism of the lubricant which lubricates the sliding sections in the sealed container and the return mechanism which separates the lubricant from the operation gas discharged from the sealed container to return the lubricant into the sealed container, the lubricant can smoothly be supplied to the respective sliding sections of the stirling cycle. Since the system includes the return mechanism which separates the lubricant from the operation gas to return the lubricant into the sealed container, for example, a disadvantage that the lubricant is mixed with the operation gas and surplus lubricant flows into the rotary-type low-temperature compression mechanical section and the like can be avoided. In consequence, an operation of the stirling cycle can smoothly be performed, and prevention of output deterioration, performance deterioration of the stirling cycle and the like can securely be prevented.

In addition, according to the fifth invention, the freezer system comprises the motor which drives the driving shaft and operates the stirling cycle of the stirling system according to any one of the first to fourth inventions in the reverse cycle, so that the freezer system can be constructed using compression and expansion of the operation gas accompanying operations of the rotary-type low-temperature compression mechanical section and the rotary-type high-temperature expansion mechanical section. When a natural operation fluid such as hydrogen or helium is used in the operation gas, the system can be applied even to a freezer field having an excellent environmental property. Therefore, both of the generator and the freezer can be used, and convenience of the stirling system can largely be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical side view (a partially schematic diagram) of a stirling system according to one embodiment of the present invention; and

FIG. 2 is a conceptual diagram of the stirling system according to the embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention is mainly characterized in that a weight of a stirling system is reduced to raise productivity in order to improve energy efficiency and market competitiveness. A purpose of improving the energy efficiency to raise the productivity is realized by a simple structure in which a rotary-type high-temperature expansion mechanical section and a rotary-type low-temperature compression mechanical section are only stored in a sealed container.

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a vertical side view (a schematic diagram) of a stirling system 10 according to one embodiment of the present invention, and FIG. 2 is a conceptual diagram of the stirling system 10 according to the embodiment of the present invention. As shown in FIG. 1, the stirling system 10 of the present invention includes a cylindrical sealed container 12 formed of a steel plate, and driving mechanical sections (a rotary-type high-temperature expansion mechanical section 24 and a rotary-type low-temperature compression mechanical section 44) are arranged and stored in this sealed container 12.

The rotary-type high-temperature expansion mechanical section 24 is arranged on one side (on the upside in the drawing) of the sealed container 12, and the rotary-type low-temperature compression mechanical section 44 is disposed on the other side (the downside in the drawing) of the sealed container 12. Both the mechanical sections 24, 44 are fixed to a common driving shaft 14 disposed over a longitudinal direction of the sealed container 12, and a press feed mechanism 15 is disposed on the other side (the downside in the drawing) of this driving shaft 14. The press feed mechanism 15 presses and feeds a lubricant 70 (corresponding to the lubricant of the present invention) stored on the other side of the sealed container 12 from a supply passage of the lubricant 70 disposed beforehand in the sealed container 12 to sliding sections where a first rotor 28 (including a first vane 30), a second rotor 48 (including a second vane 50), the rotary-type low-temperature compression mechanical section 44 and the like slide to lubricate the sections. This press feed mechanism 15 presses and feeds the lubricant 70 into a first cylinder 26 and a second cylinder 46 with a centrifugal force generated by rotating, for example, a spirally curved spiral groove or a propeller-like portion. It is to be noted that a technology of press-feeding the lubricant 70 with the press feed mechanism 15 has heretofore been a well-known technology, and hence detailed description is omitted.

A partition wall 16 is disposed between the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44, and the sealed container 12 is divided into a rotary-type high-temperature expansion mechanical section 24 side and a rotary-type low-temperature compression mechanical section 44 side by this partition wall 16. That is, the rotary-type high-temperature expansion mechanical section 24 is disposed on one side (the upside in the drawing) of the partition wall 16, and the rotary-type low-temperature compression mechanical section 44 is disposed on the other side (the downside in the drawing). The partition wall 16 includes an insulation wall using a porous material and having a high insulation property or an insulation wall provided with an inner vacuum space and having a high insulation property, and preferably insulates between the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44. A control mechanism 18 is disposed between the rotary-type low-temperature compression mechanical section 44 and the partition wall 16 with a predetermined space from the partition wall 16, and a generator 20 is disposed between the rotary-type low-temperature compression mechanical section 44 and the press feed mechanism 15 so as to substantially come in close contact with an inner surface of the sealed container 12 and have a predetermined space from the control mechanism 18. A predetermined space is disposed around the control mechanism 18, and this space is provided with a second space 44A. This control mechanism 18 preferably controls a performance characteristic of the stirling system 10, and preferably regulates phase angles of compression upper dead points of both of the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44.

Moreover, the generator 20 is a generator which is also usable as a motor and in which power generation and the motor are so-called reversibly usable. This generator 20 generates power to output the power during an operation of the stirling system 10 (during rotation of the driving shaft 14). The generator 20 is constituted so that a power source externally disposed beforehand is energized to operate the generator 20 as the motor at the start of the stirling system 10 and that the motor automatically switches to the generator 20 at a time when a sufficient shaft output is generated. In such a sealed container 12, the rotary-type high-temperature expansion mechanical section 24, the rotary-type low-temperature compression mechanical section 44, the control mechanism 18, the generator 20 and the lubricant 70 are contained. In consequence, a simple and optimum shape structure of the stirling system 10 is realized, and performance, capacity and weight of the system are constituted so as to obtain pressure air tightness, cost reduction, practicality and convenience. It is to be noted that the control mechanism 18 will be described later in detail.

Here, a mechanical section of a rolling piston type will hereinafter be described as an example. The rotary-type high-temperature expansion mechanical section 24 includes the first cylinder 26 having an outer peripheral surface substantially brought into close contact with the inner surface of the sealed container 12 and the first rotor 28 rotatably disposed in this first cylinder 26. The rotary-type high-temperature expansion mechanical section 24 has predetermined capacity spaces at both of a space between the partition wall 16 and the first cylinder 26 and a space between the first cylinder 26 and a surface on the side (the upside in FIG. 1) opposite to the partition wall 16 to form a first space 24A. The first cylinder 26 includes the first vane 30 whose tip end portion usually abuts on the first rotor 28, and the first cylinder 26 is divided into a high-temperature discharge side and a high-temperature suction side by this first vane 30. That is, the first cylinder 26 is divided into a high-temperature side discharge port 34 of the first vane 30 as the high-temperature discharge side and a high-temperature side suction port 32 side as the high-temperature suction side by the first vane 30 (shown in FIG. 2).

The center of the first rotor 28 is fixed to a crank shaft 14A (a solid line in FIG. 2) of the driving shaft 14 (a dotted line in FIG. 2), and this driving shaft 14 crank-rotates, whereby the first rotor rolls in the first cylinder 26. That is, the first rotor 28 rolls around a rotary shaft center which is the center of the first cylinder 26 in the first cylinder 26. The first cylinder 26 is provided with a heater 38A (shown in FIG. 2) which supports the isothermal heating of the operation gas to be sucked on the high-temperature suction side.

Moreover, the rotary-type low-temperature compression mechanical section 44 includes the second cylinder 46 having an outer peripheral surface substantially brought into close contact with the inner surface of the sealed container 12 and the second rotor 48 rotatably disposed in the second cylinder 46. The second cylinder 46 is provided with the second vane 50 whose tip end portion usually abuts on the second rotor 48, and the second cylinder 46 is divided by this second vane 50. That is, the second cylinder 46 is divided into a low-temperature side discharge port 54 side of the second vane 50 as a low-temperature discharge side and a low-temperature side suction port 52 side as a low-temperature suction side by the second vane 50 (shown in FIG. 2). The stirling system 10 includes a rotary mechanism (a rolling piston type) having the first rotor 28 and the second rotor 48 disposed in the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44, respectively.

The second rotor 48 is fixed to the crank shaft 14A of the driving shaft 14, and this driving shaft 14 crank-rotates, whereby the second rotor rolls in the second cylinder 46. That is, the second rotor 48 rolls around a rotary shaft center which is the center of the second cylinder 46 in the second cylinder 46. The second cylinder 46 is provided with a cooler 58A (shown in FIG. 2) which supports the isothermal cooling of the operation gas sucked into the low-temperature suction side from the outside of the second cylinder 46.

The high-temperature side discharge port 34 of the first cylinder 26 constituting the rotary-type high-temperature expansion mechanical section 24 is connected to a hollow connection pipe 36, and this connection pipe 36 is connected to the low-temperature side suction port 52 of the second cylinder 46 constituting the rotary-type low-temperature compression mechanical section 44 via a first cooler 58 (a dotted line in FIG. 1). The low-temperature side discharge port 54 of the second cylinder 46 is connected to a hollow connection pipe 56. This connection pipe 56 is connected to the high-temperature side suction port 32 of the first cylinder 26 constituting the rotary-type high-temperature expansion mechanical section 24 via a first heater 38 (a solid line in FIG. 1).

A regenerative heat exchanger 60 requires a function of accumulating heat to preliminarily cool the operation gas at a time when the gas flows into the regenerative heat exchanger 60 from the rotary-type high-temperature expansion mechanical section 24 side at a high temperature, and discharging heat to preliminarily heat the operation gas at a time when the gas flows into the exchanger from the rotary-type low-temperature compression mechanical section 44 side. The regenerative heat exchanger 60 includes, for example, a double piping line, a plate type sensible heat exchanger structure and the like so that flows (counter flows) of the operation gas passing in opposite directions in the exchanger are not mixed, and heat exchange is facilitated. In this case, the regenerative heat exchanger 60 performs only sensible heat exchange of the operation gas, and hardly accumulates or discharges the heat. Such a regenerative heat exchanger 60 does not require any complicated internal filler such as mesh, and constituted in a comparatively small capacity.

The regenerative heat exchanger 60 and a return mechanism 62 are important elements constituting the present invention, and are arranged outside the sealed container 12 in principle. That is, in the stirling system 10, the first cylinder 26, the regenerative heat exchanger 60, the return mechanism 62, the first cooler 58, the second cylinder 46, the return mechanism 62, the regenerative heat exchanger 60, the first heater 38 and the first cylinder 26 are successively connected to one another via pipes to constitute an annular operation gas circulation circuit (hereinafter referred to as the stirling cycle). It is to be noted that in FIG. 2, the regenerative heat exchanger 60, the return mechanism 62, the first heater 38, the second heater 38A, the first cooler 58 and the second cooler 58A arranged outside the sealed container 12 are shown by dotted lines.

Moreover, a predetermined amount of a high-pressure operation gas such as a hydrogen gas, a helium gas or a nitrogen gas is introduced as the operation gas in the stirling cycle, and a predetermined amount of silicon-based oil is introduced as the lubricant 70 for use in the stirling cycle. Conditions such as a pressure and an inner capacity of the operation gas introduced in the stirling cycle, eccentricities of the first rotor 28 and the second rotor 48, a difference between the phase angles of the rotors, inflow and discharge heat amounts and a temperature are selected and set beforehand so as to constitute the stirling cycle.

Furthermore, the return mechanism 62 separates the lubricant 70 from the operation gas and removes deposit to return the lubricant into a lower part of the sealed container 12, and includes, for example, a gear pump and a filter having a lubricant 70 separating function of adsorbing the lubricant 70 to separate the lubricant from the operation gas. That is, the return mechanism 62 returns the lubricant 70 separated from the operation gas by the return mechanism 62 into the lower part of the sealed container 12 (the downside in FIG. 1) with a gear pump via a connection pipe 63 (a one dot chain line in FIG. 1).

Here, the conventional stirling cycle of the reciprocation system is usually formed by laminating a finely meshed metal in multiple layers, because the operation gas including the lubricant reciprocates between the rotary-type high-temperature expansion mechanical section (a high-temperature section) at a high temperature and the rotary-type low-temperature compression mechanical section (a low-temperature section) at a low temperature. In consequence, the regenerative heat exchanger is constituted so that the operation gas touches a large contact area, and sufficient heat accumulation and discharge effects are obtained with a fluid resistance which is as small as possible. However, when the lubricant is heated at the high-temperature section to change a property thereof and the deposit is generated, the regenerative heat exchanger through which the lubricant passes before reaching the low-temperature section might be clogged. Therefore, lubrication in the stirling cycle by use of the lubricant and sealing cannot sufficiently be performed.

To solve the problem, in the present invention, the press feed mechanism 15 which press-feeds the lubricant 70 stored in the lower part of the sealed container 12 to the respective sliding sections is disposed. Moreover, the filter which separates the lubricant 70 from the operation gas and which removes the deposit is disposed in the return mechanism 62. In consequence, it is constituted that the deposit generated in the lubricant 70 is removed and that the lubrication and the sealing of the stirling cycle are preferably performed. Furthermore, the stored lubricant 70 is fed under pressure to the respective sliding portions again by the press feed mechanism 15 to cool the sliding sections and prevent wear on the sections. It is to be noted that the return mechanism 62 may be modified so that, in a case where the use of the lubricant 70 at the rotary-type high-temperature expansion mechanical section 24 is to be inhibited owing to a disadvantage that the section is thermally and easily damaged, the lubricant is separated from the operation gas circulated in the stirling cycle and used in the only rotary-type low-temperature compression mechanical section 44. It is to be noted that a technology of feeding the lubricant 70 under pressure with the gear pump is a heretofore well-known technology, and hence detailed description thereof is omitted.

Next, an operation of the stirling system 10 will be described. It is to be noted that the operation gas is heated by the first heater 38 to reach the high temperature at the rotary-type high-temperature expansion mechanical section 24, and the gas is cooled by the second cooler 58A to reach the low temperature at the rotary-type low-temperature compression mechanical section 44. Therefore, since it is thermodynamically advantageous to vertically dispose the sealed container 12 for use so that the rotary-type high-temperature expansion mechanical section 24 is positioned at an upper part and the rotary-type low-temperature compression mechanical section 44 is positioned at a lower part, a state in which the sealed container 12 is vertically disposed will be described in the embodiment. The control mechanism 18 and the generator 20 are arranged in the same space as the rotary-type low-temperature compression mechanical section 44 side in order to prevent the heating. As a heating source of the first heater 38 (including the second heater 38A), for example, fossil fuel, biomass fuel, micro gas turbine or fuel cell exhaust heat, factory exhaust heat, solar heat or the like is used. As a cooling source of the first cooler 58 (including the second cooler 58A), for example, underground water, river water, pond water, seawater, air (outside air at ordinary temperature) or the like is used. Namely, the first heater 38 and the second heater 38A are heated by the heating source. The isothermal heating of the first cylinder 26 is made by the second heater 38A. The first cooler 58 and the second cooler 58A are cooled by the cooling source. And the isothermal cooling of the second cylinder 46 is made by the second cooler 58A.

Moreover, both the rotors 28, 48 which come in contact with the inner surfaces of the cylinders 26, 46 to roll are set based on basic points of both the vanes 30, 50 so that the difference between the phase angles is about 180 degrees. In this case, the first cylinder 26 and the second cylinder 46 are arranged so that eccentric directions are set to opposite phases so as to cancel vibrations and obtain a low vibration. It is to be noted that a phase angle difference of 180 degrees indicates a time when the discharge of the operation gas from the rotary-type high-temperature expansion mechanical section 24 is started, and suction of the operation gas into the rotary-type low-temperature compression mechanical section 44 is started. The first rotor 28 is connected to the second rotor 48 by the driving shaft 14, and the high-temperature side suction port 32, the low-temperature side suction port 52, the high-temperature side discharge port 34 and the low-temperature side discharge port 54 of both of the cylinders 26, 46 are disposed on the same side surface.

Furthermore, the operation gas which flows into the first cylinder 26 (the high-temperature suction side) is heated by the first heater 38. Since the first cylinder 26 is heated by the second heater 38A, the operation gas substantially isothermally expands, a predetermined high pressure is obtained in the first cylinder 26. This high-pressure operation gas allows the first rotor 28 to roll along the inner surface of the first cylinder 26 in a clockwise direction (an arrow in FIG. 2), and the operation gas is sucked from the connection pipe 56 into the high-temperature suction side. Moreover, the lubricant 70 is fed under pressure to the respective sliding sections, the first cylinder 26 and the second cylinder 46 by the press feed mechanism 15. In this manner, the rotary-type high-temperature expansion mechanical section 24 obtains a driving force from the heating source to rotate the driving shaft 14.

When the first rotor 28 rolls, the operation gas in the first cylinder 26 (on the high-temperature discharge side) is discharged into the connection pipe 36 from the high-temperature side discharge port 34. The operation gas discharged into the connection pipe 36 travels in an arrow direction (a rightward arrow in FIG. 2) to flow into the regenerative heat exchanger 60. The operation gas which has flowed into the regenerative heat exchanger 60 performs heat exchange between the gas and the operation gas cooled by the second cylinder 46, and is cooled (preliminarily cooled). The operation gas which has exited from the regenerative heat exchanger 60 flows into the return mechanism 62 where the operation gas is separated from the lubricant 70. The operation gas separated from the lubricant 70 flows into the first cooler 58, and is cooled, and then flows from the low-temperature side suction port 52 into the second cylinder 46 (the low-temperature suction side). It is to be noted that the lubricant 70 fed under pressure by the press feed mechanism 15 circulates with the operation gas in the rotary-type high-temperature expansion mechanical section 24, and performs sufficient lubrication and sealing of the stirling cycle together with the operation gas.

At this time, the operation gas in the second cylinder 46 (the low-temperature discharge side) is cooled by the second cooler 58A. When this operation gas is cooled, the gas is substantially isothermally compressed, whereby a volume of the operation gas is compressed in the second cylinder 46. The second rotor 48 rolls along the inner surface of the second cylinder 46 in the clockwise direction (an arrow in FIG. 2), and the operation gas is sucked from the connection pipe 36 on the low-temperature suction side. Then, the operation gas in the second cylinder 46 (on the low-temperature discharge side) is discharged from the low-temperature side discharge port 54 into the connection pipe 56. The operation gas discharged into the connection pipe 56 travels in an arrow direction (a leftward arrow in FIG. 2), and the operation gas is separated from the lubricant 70 in the return mechanism 62. The operation gas separated from the lubricant 70 flows into the regenerative heat exchanger 60, performs heat exchange between the gas and the operation gas heated by the first cylinder 26, and is heated (preliminarily heated).

Then, after the heated operation gas is heated by the first heater 38, the gas returns from the high-temperature side suction port 32 into the first cylinder 26 (on the high-temperature suction side). In this manner, the rotary-type high-temperature expansion mechanical section 24 obtains a driving force to rotate the driving shaft 14. In the whole stirling system 10, since functions are simply shared by components such as the regenerative heat exchanger 60, the first heater 38 and the first cooler 58 based on the operation gas in the stirling system 10, the system is fundamentally simplified, and a continuous operation can be performed. A flow of the operation gas in the regenerative heat exchanger 60 is not a reciprocating flow, and is divided into the connection pipe 36 and the connection pipe 56 between the high-temperature section (the rotary-type high-temperature expansion mechanical section 24) and the low-temperature section (the rotary-type low-temperature compression mechanical section 44), and counter flows of one-directional flows are constituted so that the heat exchange between the flows can be performed.

That is, in the stirling system 10, the rotary-type high-temperature expansion mechanical section 24 operates to produce the driving force and drives the driving shaft 14, and power is generated by the generator 20 fixed to the driving shaft 14. The stirling system 10 performs a compressing or expanding function to generally produce an output in a state in which both of the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44 are nearly isothermal. After an external heat source is added to the first heater 38 and the second heater 38A, conducted to the operation gas and converted into the power, the heat is discharged as the exhaust heat from the first cooler 58 and the second cooler 58A. As a result, thermodynamic stages are continuously realized to complete the stirling cycle, and the system functions as an engine.

Here, in the stirling cycle as an external combustion engine, since the heat is obtained from the outside, responsive reaction to the power transmission is delayed in relation to the heat conduction. An ideal phase angle difference with which this stirling cycle can exhibit a maximum capability is 180 degrees. When the difference of the phase angle is 0 degree, the system does not operate. However, when the phase angle is 180 degrees, a thermodynamical capability is not necessarily 100%. To solve the problem, it is constituted that the phase angle can be regulated by the control mechanism 18 so as to obtain the maximum outputs from the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44. It is also constituted that the phase angle can be regulated during the operation of the stirling cycle so as to vary the driving force.

That is, the control mechanism 18 has a function of appropriately changing a rotary phase difference between the first rotor 28 of the rotary-type high-temperature expansion mechanical section 24 and the second rotor 48 of the rotary-type low-temperature compression mechanical section 44 so that a thermodynamic characteristic of the stirling cycle is changed to control the performance characteristic. Examples of a structure of the control mechanism 18 include a structure in which a gear disposed at the driving shaft 14 on the rotary-type high-temperature expansion mechanical section 24 side engages with a gear disposed on the opposite rotary-type low-temperature compression mechanical section 44 side to regulate the phase angle and a structure in which the phase angle is regulated with an electromagnetic clutch or the like. The phase angle difference between the rotors 28 and 48 is set to about 180 degrees based on both the vanes 30, 50 as the basic points as described above, but the control mechanism 18 freely changes this phase angle difference to exhibit the maximum capability of the stirling cycle.

Moreover, in the stirling cycle, in a case where a load decreases in a short time (e.g., within about one minute) to reduce the capability, even when an input (heating and cooling) is reduced to the half, the capability cannot easily be reduced owing to an influence of remaining heat and inertia. To solve the problem, when the control mechanism 18 displaces the phase angle difference as much as a predetermined angle, the capability can be reduced. Therefore, when the load is varied, the output (the power) of the generator 20 can be changed, so that it is possible to prevent a disadvantage that an amount of the power to be generated excessively increases at a time when the load is reduced. It is to be noted that a technology of the control mechanism 18 to displace the phase angles of both the rotors 28, 48 by engagement of the gears, by use of the electromagnetic clutch or the like is a heretofore well-known technology, and hence detailed description thereof is omitted.

Furthermore, since the operation gas flows in only one direction in the present stirling cycle, the clogging of the regenerative heat exchanger 60 is not easily caused, so that the stirling cycle using the lubricant 70 can safely be constructed. When the lubricant 70 is circulated through the stirling cycle, sealability and lubricating property can remarkably be improved as compared with the conventional technology. In consequence, the first heater 38, the first cooler 58 and the regenerative heat exchanger 60 forming the basis of the present invention can be integrated with the sealed container 12 inside or outside the sealed container 12, and the system can largely be simplified. Therefore, the performance characteristic of the stirling system 10 can largely be improved. Moreover, preparation precisions, materials, surface treatments and the like of the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44 can remarkably be simplified.

In addition, since the control mechanism 18, the generator 20 and the like are stored in the rotary-type low-temperature compression mechanical section 44 side of the sealed container 12, a mechanism to extract an output shaft (the driving shaft 14) from the sealed container 12 becomes unnecessary, and leakage of the operation gas can be prevented. Furthermore, the system might not be damaged owing to be heated excessively. Since the generator 20 is disposed in the second space 44A, a generated heat content can be cooled to avoid the superheat in a case where the generator 20 is used as the motor, As a result, when the control mechanism 18, the generator 20 and the like are brought into close contact with the sealed container 12, the sealed container 12 can be miniaturized, and conveying property and installing property can remarkably be improved.

Moreover, in the stirling cycle, when the rotary-type high-temperature expansion mechanical section 24 side and the rotary-type low-temperature compression mechanical section 44 side usually perform heating and cooling or substantially isothermal expansion and substantially isothermal compression, and thermodynamic cycles of substantial iso-capacity movements are arranged so as to aid with each other between the first cylinder 26 and the second cylinder 46 (effect of heat reuse and regeneration), so that innovative, rational and high efficient heat cycle which has not heretofore been obtained can be realized. It is to be noted that practically in the stirling cycle, even when a step portion of the substantial iso-capacity movement deviates and changes in a isobaric movement (referred to as an Erickson cycle) direction, the system having the basic constitution according to the present invention can obtain the above-mentioned excellent characteristics as it is. Therefore, it can be recognized that an effect of heat reuse and regeneration is equivalent to that of the stirling cycle.

As described above, in the stirling cycle of the present invention, the rotary-type high-temperature expansion mechanical section 24, the rotary-type low-temperature compression mechanical section 44 and the driving shaft 14 common to both the mechanical sections are stored in the sealed container 12. The sealed container 12 is divided into the rotary-type high-temperature expansion mechanical section 24 side and the rotary-type low-temperature compression mechanical section 44 side by the partition wall 16. Therefore, when the control mechanism 18 to control the performance characteristic of the stirling cycle and the generator 20 (the generator can be the motor) are directly connected to the driving shaft 14 on the rotary-type low-temperature compression mechanical section 44 side in the sealed container 12, the response to the power transmission can remarkably be improved. Since the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44 are stored in the sealed container 12, the control mechanism 18, the generator 20 (the motor) and the like are not directly impacted from the outside, and wind and rain can be avoided. In consequence, it can securely be prevented that the control mechanism 18 and the generator 20 (the motor) are corroded by damages, wind and rain, and hence durability of the stirling system can largely be improved. Therefore, in the stirling cycle of the present system, the control mechanism 18 changes the phase difference between both the rotors 28 and 48 of the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44, so that generation of a stirling cycle state in which capacity changes of both the simplest mechanical sections are mutually optimum with excellent response. However, when this control is not required, the control mechanism 18 is unnecessary.

In consequence, the system having stirling engine characteristics such as high efficiency, variety of fuel and heat source, quietness and cleanness of exhaust can be put into practical use with a simple structure in which the driving mechanical sections (the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44) are sealed and integrated. Since the sealed container 12 is constituted to be cylindrical, pressure resistance, reliability and compactness can rapidly be improved, and the system can be utilized in a general energy apparatus application field requiring convenience, energy saving property, environment consciousness and the like which have not been obtained with an existing engine such as a conventional internal combustion engine.

Especially, Since the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44 are stored in the sealed container 12, when the sealed container 12 and both mechanical section 24 and 44 are constructed to arrange the center of driving shaft 14 in a straight line, the centering of the driving shaft 14 can be made very easily. In consequence, the stirling system 10 can be assembled easily, and hence remarkable cost reduction of the stirling system 10 can be achieved. And since the driving mechanical section is stored in the sealed container 12, the remarkable simplification and durability of the stirling system 10 can be secured. Since the compact stirling cycle is obtained, the weight of the system can largely be reduced as compared with the conventional stirling cycle. In consequence, the productivity can remarkably be improved, and costs can be reduced, so that the market competitiveness of the stirling system 10 can generally largely be improved.

Moreover, since the heater (the first heater 38 and the second heater 38A), the cooler (the first cooler 58 and the second cooler 58A) and the regenerative heat exchanger 60 for constituting the stirling cycle are integrated with the sealed container 12 inside or outside the sealed container 12, the stirling system 10 can easily be conveyed anywhere or can easily be installed anywhere. In consequence, conveying property, installing property and the like of the stirling system 10 can largely be improved, and versatility of the stirling system 10 can remarkably be improved.

Furthermore, since the system includes the press feed mechanism 15 of the lubricant 70 for lubricating the sliding sections in the sealed container 12 and the return mechanism 62 for separating the lubricant 70 from the operation gas discharged from the sealed container 12 to return the lubricant into the sealed container 12, the lubricant 70 can smoothly be supplied to the respective sliding sections of the stirling cycle. Since the system includes the return mechanism 62 for separating the lubricant 70 from the operation gas to return the lubricant into the sealed container 12, a disadvantage that the lubricant 70 is mixed with the operation gas to flow into the rotary-type low-temperature compression mechanical section 44 and the like can be avoided. In consequence, the stirling cycle can smoothly be operated, output deterioration can be prevented, and performance deterioration of the stirling cycle and the like can securely be prevented.

In addition, when the system includes the motor 20 to drive the driving shaft 14 and operates the stirling cycle in a reverse cycle (namely rotating the driving shaft 14 to anticlockwise in FIG. 2 and reversing the flowing direction of the operation gas), the freezer system can be constructed using the compression and expansion of the operation gas accompanying the operations of the rotary-type low-temperature compression mechanical section 44 and the rotary-type high-temperature expansion mechanical section 24. In this case, the first heater 38 and the second heater 38A may work as suction heat cooling section, whereby the heat can be absorbed from the outside to cool a target. The first cooler 58 and the second cooler 58A may work as discharge heat heater to discharge the heat to the outside. Practically, the system can be applied to a heat pump air conditioner, a fluid and low temperature chiller and an extremely low temperature freezer. When a natural operation fluid such as hydrogen or helium is used in the operation gas, the system can be applied even to a freezer field having an excellent environmental property. Therefore, both of the generator 20 and the freezer can be used, and convenience of the stirling system can largely be improved.

Moreover, it can be expected that the system can be put into practical use with a performance which is far superior to that of the conventional reciprocating type stirling cycle and with reduced costs. Since the eccentric directions of the first cylinder 26 and the second cylinder 46 are set so as to obtain reverse phases and vibrations are cancelled mutually, a noise level can largely be reduced. It is to be noted that in either the output from the generator 20 or the freezer system, a practical cycle slightly deviates from a thermodynamically ideal stirling cycle when operating, but it is an essential feature of the present invention to preserve the scope of the present invention based on the heat regenerating cycle. The structure of the stirling cycle is similar to an already popular structure usually referred to as “a sealed type two-cylinder system rotary compressor” in a compressor for freezer air conditioning, and excellent productivity and cost reduction can similarly be expected based on simplicity of the structure.

It is to be noted that in the embodiment, the sealed container 12 constituting the stirling cycle is vertically installed (the rotary-type high-temperature expansion mechanical section 24 is disposed on the upside and the rotary-type low-temperature compression mechanical section 44 is disposed on the downside), but the sealed container 12 may not be installed vertically but may be installed horizontally (a state in which the rotary-type high-temperature expansion mechanical section 24 and the rotary-type low-temperature compression mechanical section 44 are sufficiently horizontally installed). In this case, it is necessary to change the structure to a structure in which the lubricant 70 can sufficiently be supplied to the respective driving mechanical sections in the substantially horizontal state of the sealed container 12, that is, a structure in which a lower end of the press feed mechanism 15 opens in the lubricant 70 so as to pump up the lubricant 70 and feed the lubricant under pressure at a time when the sealed container 12 is horizontally disposed. In consequence, a degree of freedom in posture of the sealed container 12 can be secured, and the whole stirling system 10 can be constituted to be compact.

In addition, after the operation gas which has flows into the first cylinder 26 from the high-temperature side suction port 32 of the rotary-type high-temperature expansion mechanical section 24 passes through the first heater 38, and further passes through the first space 24A to heat the first cylinder 26 from the outside, the gas may flow into the first cylinder 26 from the high-temperature side suction port 32.

Similarly, after the operation gas which has flowed into the second cylinder 46 from the low-temperature side suction port 52 of the rotary-type low-temperature compression mechanical section 44 passes through the first cooler 58, and further passes through the second space 44A to heat the second cylinder 46 from an outer surface, the gas may flow into the second cylinder 46 from the low-temperature side suction port 52. If necessary, a rotary disc or the like for imparting a flu wheel effect is imparted to the control mechanism 18.

Moreover, the rotary mechanism of the stirling system 10 has been described with the rolling piston type, but the stirling system 10 is not limited to the rolling piston type, and the present invention is effective, even when a rotary mechanism of a scroll type including a fixed scroll and a rocking scroll is used. Furthermore, in addition to the rotary mechanism (the rolling piston type) which achieves the purpose of the stirling system 10, examples of similarly applicable candidates in principle include “a swing rotor type” and “a multi-vane type”, and include “a Wankel type” as the case may be. Even if such type constitutes the stirling system 10, the present invention is effective.

Furthermore, in the embodiment, the shape, the dimension and the like of the stirling system 10 have been described, but the stirling system 10 may be changed without departing from the scope of the present invention. Needless to say, the present invention is not limited to the above embodiment. Even if the present invention is variously modified without departing from the scope of the present invention, the present invention is effective.

Claims

1: A stirling system wherein a rotary-type high-temperature expansion mechanical section and a rotary-type low-temperature compression mechanical section which constitute a stirling cycle, and a driving shaft common to both the mechanical sections are stored in a sealed container, and the sealed container is divided into a rotary-type high-temperature expansion mechanical section side and a rotary-type low-temperature compression mechanical section side by a partition wall.

2: The stirling system according to claim 1, wherein a control mechanism which controls a performance characteristic of the stirling cycle, and a generator or a motor are directly connected to the driving shaft on the rotary-type low-temperature compression mechanical section side in the sealed container.

3: The stirling system according to claim 1 or 2, wherein a heater, a cooler and a regenerative heat exchanger which constitute the stirling cycle are integrated with the sealed container inside or outside the sealed container.

4: The stirling system according to claim 1 or 2, which further comprises: a press feed mechanism of a lubricant which lubricates sliding sections in the sealed container; and a return mechanism which separates the lubricant from an operation gas discharged from the sealed container to return the lubricant into the sealed container.

5: A freezer system in which the stirling system according to claim 1 or 2 is used, the freezer system comprising a motor which drives a driving shaft and configured to operate a stirling cycle of the stirling system in a reverse cycle.