JPH0323742B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention uses a working fluid mainly as a gas (in special cases, there are also liquids, mixed gases, and two-phase gases), and the thermal cycle is ideal. Specifically, it concerns the equipment configuration of a Stirling cycle engine that consists of two isovolumic processes and two isothermal processes.

(Prior Art) As a prior art related to the present invention, there is one disclosed in, for example, Japanese Patent Application Laid-open No. 49538/1983. In this conventional technology, in a double-acting type Stalin cycle engine, a cavity having a volume larger than the discharge volume of the cylinder is provided in the piston, and the cavity and the working space are communicated between two piston rings. A groove is provided to allow the leakage of working gas through one of the pistons into the cavity of the piston.

However, in order to reduce the loss associated with the piston reciprocating mechanism, in order to reduce the weight of the piston and consider making the piston thinner and pressurizing the space inside the space, it is difficult to supply working gas into the space. Since this is only leakage from the piston rings, it cannot follow sudden changes in operating pressure, and as a result, the inside of the piston cavity is not pressurized sufficiently, increasing the strength of the piston. There is a problem in that it is necessary to increase the weight to ensure its strength, and it is not possible to reduce the loss associated with the vertical reciprocating mechanism.

(Problems to be Solved by the Invention) The above-mentioned problems are solved by pressurizing and sealing the inside of the piston in advance in the device disclosed in JP-A-53-57337, but in this reverse device, In this case, high-pressure piping must be installed to supply high-pressure gas to the inside of the piston, and it must be sealed under high pressure.

For example, in the embodiment shown in FIG. 5 of this publication, an example is shown in which after high-pressure gas is supplied from the piping, the middle of the piping is crushed and welded to seal it.
The figure shows an example in which the seal bolt is tightened to seal after supplying high pressure gas from the seal bolt.

Therefore, since this conventional device pressurizes and seals under high pressure, the work is dangerous and time-consuming, and requires skill. The problem is that it cannot be sealed under pressure.

Therefore, in the present invention, in a Stirling cycle engine in which high pressure gas is sealed inside the piston,
The technical problem is to configure the piston so that its sealing workability is improved.

[Structure of the invention]

(Means for solving the problems) The technical means of the present invention taken to solve the above-mentioned technical problems of the present invention are two relatively long pistons with guide pistons and two relatively short pistons with guide pistons. Each cylinder with one piston,
In addition, in a Stirling cycle engine consisting of one set or a large number of heat storage units and heat exchangers that constitute two heat cycles, a relatively long piston is formed into a thin-walled cylindrical shape with many holes bored inside. A piston cap is provided with a thin metal plate or ceramic plate and a heat insulating material, and allows fluid to flow from the outside into the inside of the piston cap,
A suction check valve that prevents the flow of fluid from the inside of the piston cap to the outside, a safety valve that releases fluid to the outside when the pressure of the fluid inside the piston cap exceeds a predetermined pressure, and a mechanism that connects the piston rod. The piston cap is formed from a built-in piston element section, and the inside of the piston cap is pressurized.

(Operation) According to the technical means of the present invention described above, fluid is allowed to flow from the outside to the inside of the piston cap through the piston element constituting the piston, and fluid is allowed to flow from the inside of the piston cap to the outside. Since there is a built-in suction check valve to prevent this, when pressurizing the inside of the piston cap, even if the high pressure piping etc. is removed after pressurization, the inside of the piston cap remains sealed, so the high pressure piping remains attached. There is no need to work under high pressure, it is safe, the work is easy without requiring any skill, and the inside of the piston cap can be easily pressurized and sealed to the set pressure.

(Example) Examples embodying the technical means of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, relatively long pistons 43 and 44 with guide pistons and their relatively long cylinders 41 and 42 (hereinafter referred to as long pistons and long cylinders) create working fluid volume variable spaces 45 and 46.
(hereinafter referred to as variable space) is a variable space 49 for working fluid formed by a relatively short double-acting cylinder 47 with a guide piston and its relatively short cylinder 48 (hereinafter referred to as short piston or short cylinder). 50 via heat exchangers 51, 52, heat storage units 53, 54, and heat exchangers 55, 56.

The long pistons 43, 44 and the short piston 47 are directly connected to a device (not shown) for extracting power via piston rods 57, 58, 59 and guide pistons 60, 61, 62, or to an electric motor or generator, or via a gear chain, etc. The piston is connected to a reciprocating mechanism (rotating swash plate, sliding plate, single or multi-shaft crankshaft, etc.).

Gas spaces 63 and 64 formed by the vertical movement of the long pistons 43 and 44 and the gland seal 68
are connected to each other by pipes through fluid ports 65 and 66, and even if the long pistons 43 and 44 move up and down with a phase difference of approximately 180 degrees, the working fluid is not compressed here. Moreover, this gas space part 63,
64 and the space 72 are supplied with working fluid at an appropriate pressure by a valve compressor as shown in FIG.

Further, a space 69 formed by the grand seal 68 and the oil remover 71 is formed by the guide pistons 60 and 6.
The purpose is to remove oil entering from 1, 62, and the working fluid gas spaces 63, 64 and space 7 are sealed at high pressure (20 to 200 atmospheres).
Prevents oil from entering 2. Therefore, space 69
A mechanism is provided for returning the oil removed through the connection port 70 to a piston reciprocating mechanism (not shown) and an oil reservoir (not shown), respectively.

In addition, 73 is a clean working fluid supply port, 74
75 is a piston ring, and 75 is a guide cylinder, each of which is integrated with a crankcase (not shown).

In FIG. 4, the long pistons 43 and 44 are connected to a piston cap 80 formed of thin-walled ceramic, metal, etc.;
The suction check valve 81 allows fluid to flow into the inside 87 of the piston cap 80 and prevents fluid from flowing outward from the inside 87 of the piston cap 80, and the fluid pressure in the inside 87 of the piston cap 80 exceeds a predetermined pressure. a safety valve 82 that releases this fluid to the outside when the
The bolt 8 has a built-in nut 91 and washer 92, which are the mechanical parts that connect the piston rod 57 (59).
4 and a piston element 83 connected to the piston cap 80 by the piston cap 80.
A fluid of the same quality as the working fluid is sealed in advance at high pressure inside the 0.

Moreover, inside 87 of the piston cap 80,
In order to prevent heat loss due to the temperature difference between the cap upper part 89 and room temperature due to the variable spaces 45 and 46 that become high or extremely low temperatures, a metal plate 85 with many small holes for heat radiation and a circular part that floats these are used. Heat insulating materials 86 for eliminating convective heat loss due to the working fluid are alternately laminated.

According to the long piston having such a configuration, the variable space 45,
By making the piston cap 80 into a thin cylindrical shape while ensuring the strength of the piston against the high pressure of 46, the weight of the piston can be reduced, and losses related to the piston reciprocating mechanism can be reduced.

In addition, a suction check valve 8 with a set suction pressure
1, when the pressure in the gas spaces 63, 64 becomes abnormally high, this pressure can be recovered inside the piston cap 80, and the safety valve 82 keeps the pressure inside the piston cap 80 at a predetermined pressure, for example, variable. The piston cap 80 will not be destroyed since it will never exceed the maximum or intermediate pressure of the space.

As a result, conventional pistons have a diameter of 100 mm and need to be made of heat-resistant alloy and have a wall thickness of 10 mm or more to deform, but with the present invention, pistons with a diameter of 10 mm
The wall thickness may be 3mm. That is, Fig. 2 is a pressure fluctuation diagram of the working fluid in the Stirling cycle engine of the present invention (the horizontal axis is the crankshaft angle).
Although the atmospheric pressure fluctuates, if a pressure of about 200 atmospheres is sealed inside the piston cap 80, the pressure fluctuations applied to the piston cap 80 will only be about ±50 atmospheres, which will allow the piston to be made thinner and lighter. It becomes possible.

In addition, there is approximately 200% inside 87 of piston cap 80.
When sealing at atmospheric pressure, the pressure is sealed at about 100 atmospheres at room temperature, and due to the temperature gradient that occurs in the piston cap 80 in a steady state, the sealed fluid expands and the pressure rises to about 200 atmospheres.

Further, according to the long piston having such a configuration, fluid is allowed to pass from the outside to the inside 87 of the piston cap 80 through the piston element 83 constituting the piston, and fluid is allowed to pass from the inside 87 of the piston cap 80 to the outside. Suction check valve 81 that prevents the flow of
When pressurizing the inside 87 of the piston cap 80, the inside 87 of the piston cap 80 is sealed even if the high pressure piping etc. is removed after pressurization. It is safe and does not require working in
This work is easy and does not require any skill, and the pressure inside the piston cap 80 can be adjusted to the set pressure.
7 can be easily pressure-sealed.

In addition, in Fig. 4, 88 is a piston ring, and 90 is a piston ring.
is the gas seal of piston rod 57 (59),
Numeral 94 is a small hole for stopping the rotation of the long piston when the long piston and piston rods 57, 59 are connected.

In addition, for a long piston, heat insulating material 86 and metal plates 85 are alternately laminated on a piston cap 80, and a piston element 83 with a suction check valve 81 and a safety valve 82 attached to the piston cap 80 is attached to a bolt 84.
It can be manufactured independently by attaching it with.

When actually installed in a Stirling cycle engine, the threaded portions 93 of the piston rods 57, 59 via the guide pistons 60, 62 are connected by the crankcase/piston reciprocating mechanism using the nuts 91 and washers 92 in the piston element 83. tighten.

In addition, in this embodiment, variable spaces 45, 46, 49, 50 for high-pressure working fluid formed by long and short pistons and respective cylinders, guide pistons 60, 62, 61, which are usually lubricated with oil, and Gas spaces 63, 64 and a space 72 into which a medium-pressure clean working fluid enters are provided between the crankcase containing the piston reciprocating mechanism, and a pressure difference is provided between the crankcase and the crankcase. In addition, spaces 69 are provided between the gas spaces 63, 64 and the space 72 and the guide pistons 60, 62, 61, respectively, in which oil in the working fluid can be drained at low pressure and returned to the crankcase. It is being As a result, the guide pistons 60, 6
2, 61 and the crankcase containing their piston reciprocating mechanisms enter the variable spaces 45, 46,
50. Intrusion into multiple heat exchangers and heat storage devices is prevented.

In addition, as shown in FIG. 3, the short piston shown in FIG. , it can also be configured as a working fluid compressor that sucks and compresses the working fluid using the variable volume space 2v. According to this, even when the pressure of the working fluid decreases,
The working fluid in the crankcase can be returned cleaner and at a higher pressure than 116. Note that working fluid always leaks little by little from the variable space made up of the long and short pistons into the crank chamber through the pistons, rings, rods, and seals. Therefore, as mentioned above, the small piston 11 is attached to the short piston.
By connecting 0 and attaching suction and discharge valves 111 and 112 to form a compressor, the working fluid from the crank chamber can be returned cleanly, and the variable volume spaces 49 and 50 (variable Buffer tank 11 during piping to space 45, 46)
7. If the regulating valve 118 is installed, the gas spaces 63, 64, variable spaces 49, 59 (variable space 4
5, 46), the pressure in the space 72 can be adjusted appropriately. That is, in the same way as increasing the pressure in the variable space to prevent water from entering through the crankcase, the generated power of the prime mover and the freezing temperature and freezing output of the refrigerator are adjusted. As shown in Figure 3, the relatively long piston/cylinder has a convex shape or multiple stages of small pistons, so that two (1)
(v, 2v) or a plurality of working fluid expansion or compression spaces.

FIG. 5 shows an embodiment in which the Stirling cycle engine of the present invention is configured with four sets of heat cycles and applied to a large-sized prime mover, with double-acting short pistons with guide pistons installed at both ends of the crankshaft. Including the long piston of the above-mentioned configuration with a guide piston, each piston is arranged at a bank angle of 45 degrees.

According to this, 12 pistons reciprocate, but the 8 long pistons generate power at each crank angle of 45 degrees, and at the same time the 4 short pistons also compress the working fluid (negative power), so By reducing the weight of the piston as described above, losses related to the crank mechanism can be reduced, and the dynamic balance is good, and vibrations can be almost completely eliminated. Further, since short pistons are arranged at both ends of the crankshaft, heat exchangers (four sets of 55 and 56 in FIG. 1 are required, also called heater tubes) heated to high temperatures can be easily assembled.

〔Effect of the invention〕

As described above, in the present invention, a fluid of the same quality as the working fluid is pre-filled inside the piston cap at high pressure, so the piston cap can be shaped into a thin-walled cylindrical shape while ensuring the strength of the piston against the high pressure in the variable space. As a result, the weight of the piston can be reduced, and losses related to the piston reciprocating mechanism can be reduced.

In addition, when the pressure in the gas space becomes abnormally high, a suction check valve with a set suction pressure allows this pressure to be recovered inside the piston cap, and a safety valve reduces the pressure inside the piston cap to a predetermined pressure. , for example, cannot exceed the maximum or intermediate pressure in the variable space, so that the piston cap cannot be destroyed.

As a result, conventional pistons have a diameter of 100 mm and need to be made of heat-resistant alloy and have a wall thickness of 10 mm or more to deform, but with the present invention, pistons with a diameter of 10 mm
The wall thickness may be 3mm. That is, Fig. 2 is a pressure fluctuation diagram of the working fluid in the Stirling cycle engine of the present invention (the horizontal axis is the crankshaft angle).
Air pressure fluctuates, but if we seal a pressure of about 200 atm inside the piston cap, the pressure fluctuations applied to the piston cap will only be around ±50 atm, making it possible to make the piston thinner and lighter. .

Furthermore, the long piston having such a configuration allows fluid to flow from the outside into the piston cap through the piston elements constituting the piston, and prevents fluid from flowing from the inside of the piston cap to the outside. Since there is a built-in suction check valve, when pressurizing the inside of the piston cap, the inside of the piston cap remains sealed even if the high-pressure piping, etc. is removed after pressurization, so that the high-pressure state can be maintained with the high-pressure piping attached. The piston cap is safe and does not require any skill, and the inside of the piston cap can be easily pressurized and sealed to the set pressure.

[Brief explanation of the drawing]

FIG. 1 shows a basic equipment configuration diagram of an embodiment of a Stirling cycle engine according to the present invention. Second
The figure shows a pressure fluctuation diagram in one embodiment shown in FIG. FIG. 3 is an explanatory diagram of the embodiment shown in FIG. 1 in which the short piston is reconfigured into a compressor. FIG. 4 shows a cross-sectional view of the long piston in one embodiment shown in FIG. FIG. 5 shows an explanatory diagram of the arrangement of long and short piston groups when the Stirling cycle engine according to the present invention is composed of four sets of thermal cycle engines. 41, 42... Cylinder, 43, 44... Relatively long piston, 45, 46... Variable space, 47
...Relatively short piston, 48...Cylinder, 4
9,50...Variable space, 51,52...Heat exchanger, 53,54...Regenerator, 55,56...Heat exchanger, 57,59...Piston rod, 60,6
1, 62... Guide piston, 63, 64... Gas space (variable gas space), 69... Space (gas space), 72... Space, 80... Piston cap, 81... Suction check valve , 82... safety valve, 83... piston element (piston element part),
85...Metal plate (ceramic plate), 86...Insulating material, 87...Interior, 91...Nut (mechanical part),
92... Watushiya (mechanism department).

Claims (1)

[Claims] 1. Two heat cycles are constructed by two relatively long pistons with guide pistons and one relatively short piston with guide pistons, as well as a large number of heat storage devices and heat exchangers. In a Stirling cycle engine consisting of one set or a large number of pistons, the relatively long piston is a piston having a thin cylindrical shape and having a thin metal plate or ceramic plate with many holes bored therein and a heat insulating material disposed inside the piston. a suction check valve that allows fluid to flow from the outside into the piston cap and prevents fluid from flowing from the inside of the piston cap to the outside; A Stirling cycle engine which pressurizes the inside of the piston cap, comprising a safety valve that releases the fluid to the outside when the pressure exceeds a predetermined pressure, and a piston element section that incorporates a mechanism section that connects the piston rod.