WO1983004281A1

WO1983004281A1 - Thermal engine

Info

Publication number: WO1983004281A1
Application number: PCT/DE1983/000097
Authority: WO
Inventors: Franz X. Eder
Original assignee: Eder Franz X
Priority date: 1982-05-27
Filing date: 1983-05-27
Publication date: 1983-12-08
Also published as: DE3220071A1; EP0178348A1; DE3314705C2; EP0110905A1; DE3314705A1; AU1553583A; EP0178348B1

Abstract

A thermal engine is capable of producing mechanical power by absorbing high temperature heat and releasing low temperature heat. To this aim, a pressure cylinder (1) is divided by a displacement piston (2) into two working chambers (7, 8) which are connected together by a thermal collector (9), the cylinder and the collector being filled with high pressure gas or steam. One of the working chambers (8) is heated at a high temperature by the supply of heat, the other chamber having a low temperature due to a refrigeration effect. At least one of the working chambers (7) is connected by two non-return valves (12, 13), acting in opposite directions, with two pressure tanks (14, 15), and the two tanks under different pressures are connected by an expansion machine (16).

Description

WORKING MACHINE

The invention relates to a working machine with a pressure cylinder and a gaseous or vaporous working medium, which emits mechanical power by external supply of heat at a higher temperature and removal of heat energy at a lower temperature. These types of heat engines have long been known as steam engines. Closed-circuit gas turbines and as Stirling engines. A disadvantage of the examples mentioned is the complicated structure and, in the case of the steam engine, the relatively poor efficiency. The invention is based on the object of creating a thermal working machine which is of simple construction and construction, works with a higher degree of efficiency and has a long service life.

The invention solves this problem in that the pressure cylinder is divided into two working spaces by a periodically reciprocating displacement piston which are connected to one another via a thermal regenerator, that pressure cylinder and thermal regenerator with a vaporous or gaseous one Arbe smedium are filled relatively high pressure, that one of the work rooms brought to a higher temperature by supplying heat, the other is kept at a lower temperature by cooling, that at least one work room is connected to two pressure vessels via two oppositely effective check valves and that the pressure vessels are connected to different pressures of the gaseous or vaporous working medium via an expansion machine. The working machine according to the invention has the advantage that it is relatively simple in design, that the displacement piston only has to push the working medium back and forth over the parallel thermal regenerator, for which purpose a simple and long-lasting sealing of the piston guide and a low level Drive power is sufficient. Because of the high applicable temperatures in the "hot" work area of e.g. 600 to 800 ° C and the ambient temperature in the

O PI - ά -

cold working space a high thermodynamic efficiency can be achieved.

Further refinements and details of the invention emerge from the subclaims.

The invention is explained in more detail below on the basis of an exemplary embodiment shown in the drawing. The drawing shows:

Fig.l is a schematic representation to explain the principle of the invention; 2 shows a schematic view of the entire work machine according to the invention and

3 shows a vertical section of the working machine according to the invention. In Fig.l the pressure cylinder 1, which is filled with a gaseous or vaporous working medium, from 10 to 100 bar pressure, has a displacement piston 2 which, via the piston rod 4, which is pressure-tightly guided through the cylinder base 3, by means of a crank mechanism 5 is periodically moved between the top and bottom dead center. The two ßrängerkolben by the 6 sealed at the end of colds with the 0-ring Ve ^'divided Ar- beϊtsräume 7 and 8 are connected to each other via the thermal regenerator 9; the same pressure of the working medium therefore prevails in them. When the displacement piston 2 moves upward, the working gas is pushed through the heat exchanger 10, the thermal regenerator 9 and the cooler 11 from the upper working space 8 into the lower 7; does the Kol¬ des Me-

The heat quantity Q ₂ at the higher temperature T _{2 is} fed to this closed process via the heat exchanger 10 and the heat quantity Q _Q at the lower temperature T is taken from the cooler 11. In the thermal regenerator 9 arises da¬ forth in the steady state, the temperature gradient T ~ T a, wo¬ by the working medium in the working chambers 7 and 8 likewise if the temp erature ^r To bzw.T2 _c assumes. Since the total mass of the working medium is independent of the position of the displacement piston and remains constant, the pressure energy of the working medium and thus the gas pressure periodically with the piston position: apart from the gas portion in the heat exchangers 10, 11 and in the thermal regenerator 9, the working medium is at the temperature T and becomes the pressure in the top dead center of the displacement piston

P., _n - ■ * T „/ ϊ (1) prevail if V is the volume displaced by piston 2 and R is the gas constant. The pressure for the bottom dead center of the displacement piston is analogous

P _max = m RT ₂ / V (2) on. The pressure of the working medium changes periodically during one revolution of the crank drive 5 between the values p ^• _m mi.n and ^ max *, the pressure ratio becomes from the relationship

in practice is between 2 and 3. Apart from the flow losses of the working medium in the thermal regenerator 9 and in the heat exchangers 10, 11, and the piston friction losses, no mechanical work has to be expended for pushing the working medium back and forth.

2 shows the method of how the periodic pressure fluctuation can be used for the generation of mechanical work. The lower working chamber 7 is connected via the check valves 12, 13 with the opposite passage direction to two gas pressure containers 14, 15, in which the pressure of the working medium is p 'or p ". In the expansion machine 16 connected to the gas pressure container, the pressure drop ( p'-p ") converted into work and the mechanical power P = (p'-p") generates V (4) if V means the volume of the working medium passed through per second. The displacement piston 2 is located near the bottom dead center , a high pressure p 'arises in the working cylinder, which keeps the check valve 12 open until the pressure container 14 is inflated to this pressure. At the top dead center of 2, the low point p "of the system is reached and a determined gas quantity is exceeded the opened check valve 13 from the pressure vessel 15 r - - flow into working cylinder 1 until pressure equalization. Depending on the volume throughput of the expansion machine 16, the pressure drop (p'-p ") is set automatically; its limit value according to Eq. (3) is reached for V = 0, ie when the expansion machine is at a standstill.

Working cylinder 1 with displacement piston 2 and thermal regenerator 9 represent a compressor operated by external heat supply, which does not contaminate the working medium with lubricant and ideally moves the only movable machine part back and forth in the working cylinder 1 without force. According to the first principle of thermodynamics, the difference between the supplied and removed heat output (Q 'Q _r "* ^{π is} the mechanical power calculated by Eq. (4). The piston and the flow machine can be used as expansion machines as long as they are suitable for relatively large pressures of the working medium. Rotary piston machines according to Wanke! can also be used and offer the advantage of a quiet work process. Problems will be expected with pure gases, such as helium as working medium, since these require an expansion machine for dry running and gas sealing at high pressures is difficult, these difficulties can be overcome if a condensable gas is used as the working medium and the working pressure is chosen so high that it is; in the expansion machine, the coldest part of the entire system, condenses and acts as a lubricant and sealant.

^'The principle of the inventions shown schematically in Fig. Fertil also is applicable to ^ processes in which the upper working volume is brought to very low temperatures 8, while the lower working volume is maintained at ambient temperature for 7. In this case, the heat exchanger 10 z.

B. be placed in a bath of boiling liquid nitrogen, the temperature of which is about 80 K. According to Eq. (3), the pressure ratio is about s for this application

(300/80) = 3.7.

3 shows a constructive exemplary embodiment, only the working cylinder shown in section being dealt with. The Working cylinder 17 made of a high-temperature resistant metal alloy is closed off by the hemispherical cylinder head 18 made of the same material and is attached to the cooler 20 with its flange 19 and sealed by the O-ring 21. The cooler 20 consists of the annular housing through which water flows, with axially arranged tubes 22 through which the working medium flows. Its finely machined inner surface 23 also represents the running surface for the sliding bushing 24 of the displacer piston 25, which is provided with labyrinth grooves for dynamic sealing .

The cylinder head 18 is of a hemispherical slide. surround phrag a or radiation burner 26, which consists of the ceramic perforated plate 27 containing zirconium oxide, for example. ^'The supplied through the burner 28 gas mixture Luf comparable burns in many small non-luminous flame and brings the perforated plate 27 to glow. The outer surface of the metallic cylinder head 18 is enlarged by welded-on webs, cones 29 and the like in order to enlarge the exchange surface for the heat transfer by radiation and convection. The warm exhaust gases are returned in the sheet metal jacket 30 outside the burner 26 and used to preheat the combustion air.

On the inside of Zyl Direction head 18, metallic webs or ribs 31 are welded or durchgenietet and the working medium by the hemispherical Leitflä¬ surface 32 of ceramic material forced route from obe¬ ren working chamber 33 for thermal regenerator 34 di- _'Cht at the To take the inner surface of the cylinder head 18.

The thermal regenerator 34 consists of an annular container made of heat-insulating ceramic or glass-like material, the inner wall 35 of which at the same time represents the working cylinder in which the displacement piston 25 made of the same material slides back and forth. The .Auter¬ wall 36 of the regenerator 34 consists of the same ceramic material and at the same time forms the thermal insulation layer to the outer jacket 17. The storage mass of the regenerator 34 are balls of the same diameter (0.5 to 2 mm) made of ceramic or annular, axial inserts interspersed with thin holes. For any surface To prevent abrasion of the ball bed, the beads are immersed in a glaze solution before filling and heated in the filled regenerator to such an extent that they bake together and with the container walls 35, 36. For the periodic drive of the displacement piston 25, the technically savvy will have various solutions ready; in any case, the piston rod 37 is pressure-tight through the bottom 38 of the working cylinder ^' , to which the drive housing 39 is flanged. In addition to mechanical gears, electromagnetic or electrodynamic methods are considered for driving the displacement piston; but pneumatic or hydraulic pistons with reversed hydraulic fluid supply can also be used with advantage.

Claims

P a t e n t a n s r u c h e

Working machine with a pressure cylinder, which emits mechanical power by external supply of heat at a higher temperature and removal of heat energy at a lower temperature, characterized in that the pressure cylinder (1) is moved by a periodically reciprocating displacement piston (2 ) is divided into two work rooms (7, 8), which are connected to one another via a thermal regenerator (9), that the pressure cylinder (1) and regenerator (9) are filled with a gaseous or vaporous working medium of relatively high pressure that one of the working spaces (8) is brought to a higher temperature by supplying heat, the other (7) is kept at a lower temperature by cooling, that at least one working space (8) is provided with two counter-acting check valves (12, 13 ) is connected to two pressure vessels (14, 15) and that the pressure vessels (14, 15) are connected at different pressures via the expansion machine (16) are.

2. Ar ts machine according to claim 1, characterized in that the displacement piston (2) via a pressure-tight through the bottom (3) of the pressure cylinder (1) guided piston rod (4) by means of a mechanical, pneumatic, hydraulic or electromagnetic drive (5) is moved back and forth.

3. Working machine according to claim 1, characterized gekennzeich¬ net that the pressure cylinder (1) from a relatively thin-walled, high temperature-resistant steel tube (17) and a thick-walled inner cylinder (35) and a cylinder end (32) made of poorly heat-conducting material consists .

4. Working machine according to claim 3, characterized gekennzeich¬ net that the inner cylinder (35) is designed as a double-walled ring container (35, 36), the interior of which resembles the thermal regenerator (34) in the form of a dense bed of compact or hollow spheres Receives diameter from poorly heat-conducting material.

5. Working machine according to claim 4, characterized gekennzeich¬ net that the double-walled ring container (35, 36) and the ball filling (34) consists of ceramic or vitreous material, coated before filling with Glasurfluig¬ speed and then fired together at Glasier¬ temperature are.

6. Working machine according to claim 4, characterized in that the inner wall of the pressure cylinder (17) is lined with stacked, annular inserts made of ceramic material with regularly distributed axial bores which are sealed against one another.

7. Working machine according to claims 1 to 6, characterized ge indicates that the upper end of the pressure cylinder (17) as a hemispherical cylinder head (18) is ausgebil¬ det, which is heated by a concentrically encompassing diaphragm or radiation burner (26) , the ceramic surface (27) of which is heated by many non-luminous flames at high temperature.

8. Working machine according to claims 1 to 7, characterized ge indicates that the hemispherical cylinder head (18) on the inside and outside with thin cylindrical projections (29, 31) or thin-walled ribs made of a high-temperature-resistant metallic material is seen and the ceramic lining (32) shoots a hollow spherical volume with the cylinder head.

9. Working machine according to claims 1 to 8, characterized ge indicates that one of the pressure vessels (14, 15) is formed by the hermetically sealed crankcase or drive housing.

10. Working machine according to claims 1 to 9, characterized in that the displacement piston (25) is hollow and is made of ceramic or glass-like material.