DE955918C - Electro-thermal device for performing mechanical work - Google Patents

Description

With already known electro-thermal devices a cavity of variable size is provided for performing mechanical work, which when heated contains highly flexible work equipment that can be heated by electrical current and its boundary walls or parts thereof are movable to perform work. Provided that the cavity and a movable part of its boundary walls Cylinder and piston are made, a seal becomes

ίο required, so also with repeated actuation not the slightest amount of the working material can escape. Whether the requirement of the "absolute" Sealing by usual means, such as careful grinding in of the piston, use of stuffing boxes etc., which can be achieved is uncertain »A mixing of the working medium and the lubricant required for the piston can hardly be avoided.

The replacement of the cylinder and piston with the types of membranes known in the art, e.g. B. metal bellows etc., is also not possible here, as these are unsuitable for higher pressures and larger strokes and there is too much harmful space and too large a volume of water to be evaporated would have to.

These difficulties are to be eliminated by the subject matter of the invention and in this way a safe one Working of the device can be achieved without any maintenance. The subject of the invention consists in the Application of the separating diaphragm known in diaphragm piston pumps in such a way that the working fluid of the lubricating fluid through a

elastic membrane, ζ. Β. made of rubber. As a result, there can never be a mixture of the two Liquids occur and the working fluid cannot escape, as it is now in a perfect state enclosed space. All that remains to be sealed is between the cylinder and Piston enclosed lubricating fluid, but this is not a problem because, firstly, it is not a high one Temperature and can be selected according to its purpose ίο of high degree of toughness. In the long run, the loss of a few drops of the lubricating fluid is insignificant, whereas this is the case with the working fluid would lead to complete failure of the device. About the small loss To make the lubricant harmless, it can be useful to give your space a certain To train reserve, d. H. to hold something bigger. Essential when arranging a separating membrane is that it is relieved by the same pressure of the liquids on both sides and thus it can be made very thin and elastic even at the highest pressure. Since they are called Vapors of the working medium touch the membrane, which may consist of organic substances, so it can be useful, in order to avoid their thermal overload, with liquids to work that have a low boiling point. There are alcohol, pentane, chloroform and similar cited.

If higher pressures and thus temperatures are required, the membrane can be separated can be achieved by the hot vapors that a in the working fluid between the heating wire and the separating piston located in the membrane is arranged. The piston is also through the both sides of the hydrostatic pressure of the working fluid relieved; so there is no striving instead of penetrating neither for the vapor into the unevaporated liquid nor vice versa. One Separation of the membrane from the heating wire can also be achieved by a solid wall with openings for passage Steam can be achieved.

It can be advantageous to use the membrane from two or

several layers and possibly some space for a filler permit. This provides greater security when a membrane ruptures, increases its heat insulating properties Effect and results in the possibility of different materials for the membrane, which the adjacent fluids are adapted to choose.

The subject matter of the invention is shown in the figures in several exemplary embodiments.

The device, which essentially consists of cylinder 1 and piston 2 (Fig. 1 and 2), has a membrane 4 that separates the working fluid in space R _a from the lubricating fluid in space R _t , the volume of R _{a increases} , and the vapor pressure acts through the membrane on the lubricating liquid, which in turn presses on the piston and moves it forward. The separating membrane 4 is designed to be elastic and has sufficient flexibility to hold the necessary volume of steam. You can z. B. made of rubber or similar material (Fig. 1) or as a metal bellows (Fig. 2).

FIG. 3 shows a further separation of the working fluid into an evaporating part R _a and a non-evaporating part R _a ' by a floating separating piston 5.

The separation can, as shown in Fig. 4, also by a solid wall 6 with passage openings for the steam. The purpose here is to cover the membrane 4 against the hot resistance wire 3.

Fig. 5 shows a cylinder 1 with piston 2 and heating wire 3 with large areas F and small piston travel s without a separating membrane. In Fig. 6, however, the same cylinder 1 and piston 2 are shown in the embodiment according to the invention, but a vessel 7 with a separating membrane 4 is also arranged, which leads to a favorable hydraulic translation.

Fig. 7 illustrates a space R _a located in the cylinder 1 and completely separated by a membrane 4 :

In the structural design, there is the option of not the cylinder space itself, but one to be separated from this space, which is connected by a pipe, by a membrane, the spaces moving as far away from each other and at any. Can be arranged.

The separation of part of the cylinder for the working fluid by the separating membrane results in further advantages. A force P and a path s are required. At the optimal pressure p (for water e.g. about 15 at) there is a piston

area F = -. As shown in Fig. 5, the ratio -γ- can be so small (or so large) that

with a small volume F = FS a very large wall surface F _w = % F + χ · D · s is created, to which considerable amounts of heat are lost. It is always advantageous to design the evaporation space in such a way that it adapts itself as ideally as possible to a spherical shape, since this results in the smallest wall surface with the existing volume. This can be solved in an excellent way by arranging a separating membrane, as shown in Fig. 6. The piston area is still

P.
determined by the value -P "= -r. To the piston

in order to lift the piece s, a volume V = FS is required. The steam volume is no longer generated directly between the cylinder and piston, but in a space that is separated from the cylinder space by the separating membrane and that comes as close as possible to the ideal shape (smallest surface area for a given volume), which significantly improves the efficiency of the device can be.

It is a kind of hydraulic translation that arises here, because one room has one large area and small path, the other a relatively small area and large path.

This is also linked to the idea that in the cylinder, which is closed by a piston, a body of variable volume is located wholly or in part by an elastic membrane is separated from the rest of the cylinder contents (Fig. 7).

Claims (6)

PATENT CLAIMS: i. Electro-thermal device for performing mechanical work with a cylinder and a piston, the cylinder space containing an electrical heating device and with vaporizable Liquid is filled, characterized in that the cylinder space or a with This contiguous space is divided into two spaces by a flexible membrane (4) is, of which one, electrically heated room is the work equipment and the other, of which Piston limited space contains a lubricious, advantageously viscous liquid, so that the The hydrostatic pressure of the working medium and the membrane is essentially the same on both sides exposed to lubricious liquid. 2. Electro-thermal device for performing mechanical work according to claim 1, characterized characterized in that in the space containing the working means j a dividing this space floating and at the same time sealing piston (5) is arranged. 3 · Electro-thermal device for performing mechanical work according to claim i, characterized characterized in that in the space containing the working medium, this dividing and provided with perforations partition (6) is arranged such that only one of the formed Partial spaces the membrane has to limit. 4. Electro-thermal device for performing mechanical work according to claim 1 to 3, characterized characterized in that the space containing the working fluid to be evaporated has a ratio from surface to volume approximating that of a sphere, while the working piston area and the working piston path from the intended use of the device are adapted to the given force travel ratio. 5. Electro-thermal device for performing mechanical work according to one of claims 1 to 4, characterized in that the membrane consists of two or more layers of the same or a different material. 6. Electro-thermal device for performing mechanical work according to claim 1, characterized characterized in that the space containing the separating membrane is separated from the cylinder space and is connected to this by a pipe. Considered publications:
German patent specification No. 43 295,91 837,547 997. 1 sheet of drawings 1 609 741 1.