GB2461709A

GB2461709A - Combined steam engine and condensing steam engine

Info

Publication number: GB2461709A
Application number: GB0812492A
Authority: GB
Inventors: Huseyin Bayir
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-07-08
Filing date: 2008-07-08
Publication date: 2010-01-13
Also published as: GB0812492D0

Abstract

Power generation apparatus comprises a steam engine combined with a condensing steam engine. In a first aspect of the invention a steam transfer pipe 13 is provided between the engines, a reservoir 1 being provided in the pipe 13. The reservoir 1 may comprise a piston-like lid 21 which is moveable within a container to vary the volume of the reservoir 1. The reservoir 1 could alternatively comprise an expandable body including bellows. The steam engine and condensing steam engines may drive the same crank 31, or may alternatively drive separate cranks. In a second aspect of the invention there is provided a hot piston 6 within the steam engine, a cold piston 14 within the condensing steam engine, a crank 31, a connecting rod between the hot piston 6 and the crank 31, and a connection between the cold piston 14 and the crank 31 which includes a pivoted arm 32. In a third aspect of the invention there is provided a hot piston 6 and a cold piston 14 which are connected to each other to drive a crank 31.

Description

Improved Heat Engine The present invention relates to heat engines of the type which extracts energy both from vaporisation and from condensation.

An example of such an apparatus is disclosed in EP 0179427 in which a high pressure cylinder receives super-heated vapour and contains a piston which is displaced by the vaporisation of the fluid. A second cylinder assembly operates at lower pressure and uses the condensation of the vapour to drive a low pressure piston.

One of the difficulties with such apparatus is collecting energy from both the higher temperature cylinder and the low temperature cylinder using the same mechanical system. This is because a liquid expands into a vapour much more quickly than vapour condenses into a liquid.

A further problem is that the high temperature and low temperature cylinders operate substantially out of phase with each other, and this means that the mechanical system for converting the movement of the pistons within the chambers to a crank is more complicated because they must be on opposite sides of the crank axis.

A further problem with existing machines is that the high temperature and low temperature cylinders seem to be distant from each other, and there can be a substantial temperature loss as the steam passes from the high temperature cylinder to the low temperature cylinder.

According to a first aspect of the present invention, a combined steam engine and condensing steam engine comprises: a steam transfer pipe between the steam engine and the condensing steam engine; and a steam reservoir in the steam transfer pipe. An advantage of the invention is that the steam reservoir is able to buffer any short term differences in the volume of steam created by the steam engine and the volume of steam which can be input into the condensing steam engine.

It is preferred that the steam reservoir includes a container and a piston-like lid movable within the container. This permits the change of volume of the steam reservoir. It is also preferred that the steam reservoir is thermally insulated, thereby retaining the heat within the steam.

In one embodiment,the steam reservoir further comprises a rod connected to the piston-like lid which is movable to increase and reduce the volume of the steam reservoir by moving the piston-like lid, and a motor attached to the rod for moving the lid. In this way, the volume of the steam reservoir can be increased and reduced by operation of the motor. Such an arrangement further includes a controller for controlling the motor, and may include a pressure sensor for detecting the pressure of steam within the steam reservoir. A central processing unit may be included to control the volume of the steam reservoir and/or the speed of the steam engine and/or the speed of the condensing steam engine.

According to another embodiment, the steam reservoir includes an expandable reservoir. The expandable reservoir might include a bellows.

In some embodiments, the steam engine and condensing steam engine are arranged to drive separate cranks. This has the advantage that the speed of the steam engine and the condensing steam engine can be different. Alternatively, the steam and the condensing steam engine can be arranged so as to drive the same crank. This is advantageous in simplifying the apparatus. Further, the steam engine and condensing steam engine can be arranged to drive opposite sides of the same crank out of phase with each other, and this can also add to the mechanical simplicity of the apparatus.

According to a second aspect of the present invention, a combined steam engine and condensing steam engine comprise a hot piston within the steam engine, a cold piston within the condensing steam engine, a crank, a connecting rod between the hot piston and the crank and a connecting assembly between the cold piston and the crank, the connecting assembly including a pivoted arm. This has the advantage that the hot piston and the cold piston can drive a common crank.

Preferably, the combined steam engine and condensing steam engine further comprise a pivot about the pivoted arm turns, the pivot being located nearer one end of the arm than the other. The offset pivot gives the advantage of increased mechanical advantage and permits the use of a hot piston and a cold piston with different strokes.

It is further advantageous if the connecting assembly comprises a first rod connected to the cold piston and a second rod connected to the crank, each of the first and second rods being connected to opposite ends of the pivoted rod. In one embodiment, the hot piston and the cold piston are connected to the same side of the crank, and since they are arranged close to each other, only require a short steam pipe between the steam engine and the condensing steam engine. Alternatively, the hot piston and cold piston can be connected to opposite sides of a common crank, out of phase with each other.

A steam reservoir might then be required between the steam engine and the condensing steam engine.

According to a third aspect of the present invention, a combined steam engine and condensing steam engine comprise a hot piston, a cold piston, a crank and a body defining a hot chamber within which the hot piston moves and a cold chamber in which the cold piston moves, the hot and cold pistons being connected to each other to jointly drive the crank. In effect, a more efficient double acting type arrangement is achieved which also retains more of the heat from the steam engine.

Preferably, the pistons are fluidly connected to each other. The hot chamber and the cold chamber may be axially aligned with each other, which allows forces to be generated axially with minimum loss of energy.

It is further preferred that the hot and cold chambers are connected, and that one chamber leads into the other. The hot chamber and cold chamber are preferably of different diameters. The cold chamber is preferably much flatter than the hot chamber.

A number of embodiments of the present invention will now be described with reference to the drawings in which: Figure 1 is a schematic drawing showing an engine including a steam reservoir; Figure 2 is a schematic drawing of a second embodiment including a steam reservoir; Figure 3 is a schematic drawing showing a third embodiment in which the low temperature piston is connected to the crank via a pivoted link; Figure 4 is a schematic drawing showing a variant of the third embodiment; and Figures 5 and 6 are schematic drawings showing a fourth embodiment in which the pistons are linked.

Referring firstly to Figure 1, a combined steam engine and condensing steam engine is shown. The engine includes two hot chambers 9 within which hot pistons 6 are movable up and down. The hot pistons 6 are connected to a crank 2 via connecting rods. The hot chambers 9, hot pistons 6 connecting rods and crank 2 form a steam engine. The hot pistons are arranged so as to be 180° out of phase, so that when one piston is pushed up, the other piston is pushed down. Of course, other phases are possible. If there were three hot chambers, the angle of separation would probably be 120°, and if there were four, the angle would be expected to be 90°, and so on.

When one of the hot pistOns 6 is at or close to the bottom of its movement, an inlet water valve 10 is opened to allow entry of water into the bottom of the hot chamber 9.

The valve 10 is then closed, and the water is heated from a heat source 7 so as to be vaporised into steam. The steam exerts pressure on the hot piston 6, and pushes it upwards, and turns the crank 2.' As the hot piston 6 is pushed downwards, an exhaust steam valve 12 is opened to allow the steam to escape from the hot chamber 9. This valve 12 closes and the inlet water valve 10 opens when the hot piston 6 is at or close to the bottom of its travel, and when the steam has been expelled. The inlet water valve opens for long enough that the necessary amount of water enters the hot chamber 9, and is then closed.

The hot piston 6 in the lower position is, in fact, at its lowest position (L) with the necessary amount of water 8 in the hot chamber. On the other hand, the other piston is at its highest position (R) with the steam inside the hot chamber having expanded to its greatest volume.

The two stroke nature of this system allows the two hot pistons 1800 out of phase to One of the aims of this invention is to reduce the amount of energy lost through heated steam being exhausted. With this in mind, the exhausted steam 3 is reused. First of all, it is directed via an exhaust steam pipe 13 into a steam reservoir I where it is held for release into one of a pair of condensing steam engines. The exhaust steam pipe 13 is expected to be of a relatively large diameter to facilitate low resistance flow of the steam from the hot chamber 9. The condensing steam engines each include a cold chamber 15 within which a cold piston 14 moves reciprocally. The cold piston 14 is a very close fit within the cold chamber 15 so as to resist escape of steam. The cold pistons 14 are connected to a crank 4 via connecting rods. The crank 4 is arranged such that the pistons 14 are 1800 out of phase with each other so that, as one piston is moved down, the other is moved up.

In operation, steam 3 is fed from the steam reservoir I into one of the cold chambers via an inlet steam pipe 17 and a steam inlet valve. The steam enters the cold chamber 15 as the cold piston 14 rises. Once the cold piston has reached the top of its movement, the inlet valve is closed, and the steam will be cooled. As it is cooled, it condenses, and reduces in volume. The low pressure pulls the piston 14 downwards and drives the crank 4. Towards the bottom of the movement of the piston 14, a condensed water valve ii will open to allow the condensed water to escape which closes again once the water has been expelled, and the steam inlet valve will open to allow entry of more steam. The condensed water drains through condensed water pipes 18 into a condensed water reservoir 19. This water, which is still hot, is used to feed the hot chambers 9 in the steam engine.

It should be noted that the walls of the cold chamber 15 and/or the cold piston 14 include cooling pipes for passing coolant therethrough in order to cool the steam within the cold chamber 15. The coolant is supplied from a cooling system 5, which might include a fan and/or radiator. The fan and coolant may be driven by an electric motor or internal combustion engine.

In the condensing steam engine, the cold chamber 15 are relatively flat and wide in order to maximise the surface area for cooling purposes. Additionally, it is advantageous if the cold pistons 14 and the base of the cold chamber 15 include magnets whereby, when the piston is towards its lowest position, the magnet draws the piston into the bottom of the chamber 15 to expel the condensed water.

An important part of this embodiment is the steam reservoir 1. It should be appreciated that the steam generated within the steam engine causes the pistons to rise very quickly whereas the cold pistons tend to fall relatively slowly because condensing takes place a little longer. To compensate for the differences, the steam reservoir is there to buffer the passage of the steam from the hot chambers 9 to the cold chambers 15. The steam reservoir includes an insulated container 20 which forms a chamber within which a reservoir piston 21 moves up and down to change the volume within the steam of the insulated container 20. The reservoir piston 21 is a close fit with the insulated chamber 20 to resist the escape of steam from it. It should be appreciated that movement of the reservoir piston is simply to change the volume of the reservoir. The reservoir piston (a piston-like lid) is not intended to be driven by the steam to do work. Each time one of the hot pistons 6 falls, steam is directed very quickly into the steam reservoir, causing the reservoir piston 21 to rise fairly quickly.

However, the cold pistons 14 tend to rise more slowly, drawing the steam out of the steam reservoir more slowly. The steam reservoir 1 compensates for the different speed at which steam is exhausted from the hot chambers 9 and is taken into the cold chambers 15.

The volume of the steam reservoir I is controlled by a volume regulator 24 which controls an electric motor 22 which moves a rod 25 up and down by use of a gear train 23. The rod is, in this case, a worm drive, but other arrangements are also possible.

The steam reservoir 1 also includes a pressure gauge 26 connected to a central processing unit 30 which controls the volume regulator 24. The steam reservoir 1 is insulated with thermally insulative materials 27. The volume of the steam reservoir 1 is preferably much larger than the volume of the hot chamber 9. It may be many times larger than the volume of the hot chambers 9. This is necessary because, each time the steam is exhausted from the hot chamber 9 into the steam reservoir 1, it is not desirable to have a sudden build up of pressure within the steam reservoir and so the buffering effect is useful.

In effect, the steam reservoir I accumulates the steam from the steam engine, and stores the steam to be reused in the condensing steam engine. The condensing steam engine drives a separate crank 4 to the crank 2 driven by the steam engine.

In the steam reservoir, the volume regulator activates when there is excess pressure in the steam reservoir so that the piston 21 is moved up to increase its volume. This would normally be computerised. When the volume drops, the piston 21 is moved down. The steam reservoir could also be constructed of a bellows-like expandable steam container which is insulated against heat loss. It could be made of a flexible or a elastic material so that the more steam there is, the more the bellows expand, and the less steam there is, the more it shrinks. The natural resilience of the material would allow the volume regulator, rod and gears arrangement to be dispensed with.

However, it would require a relief valve for releasing excess steam in the event that the reservoir becomes too full.

The steam reservoir also includes a pressure relief valve for relieving any excess pressure within the steam reservoir 1. This is important as a safety mechanism to ensure that the steam reservoir will not explode under excess pressure. It should also be appreciated that the relief valve will be fitted to the steam reservoirs not only of this embodiment but all of the other embodiments in which it is used. Since the pressure relief valve can vent some of the steam to atmosphere, it may be necessary to include a water inlet to the system to replace the water that is lost. Preferably, this will feed water into the condensed water reservoir.

The valves used in this invention, 10, 11, 12 and 17 are all automatically operated to open and close at the appropriate time. It may be computerised or mechanically operated. The central processing unit 30 referred to above can be used to control the opening and closing of the valves. Further, it can be used to control the speed of operation of the steam engine and of the condensing steam engine. It will be appreciated that a balance between the two engine is required, particularly if all of the steam exhausted from the steam engine is to be used by the condensing steam engine.

Generally speaking, the same rate of steam generated from the steam engine and used by the condensing steam engine is required. The speed of the engines may be controlled by increasing or reducing the temperature of the heat source in the steam engine, and increasing or decreasing the amount of cooling of the condensing steam engine.

This also applies to the subsequent embodiments in which valves are controlled, and balancing of the steam engine and condensing steam engine is required.

Referring now to Figure 2, a combined steam engine and condensing steam engine is shown. The general principle of operation is similar to that described in Figure 1, and so, to avoid undue duplication, the description of this embodiment assumes the reader has understood the description relating to Figure 1. The steam engine includes a hot chamber 9 within which a hot piston 6 is movable up and down. The hot piston 6 is connected to a crank 31 via a connecting rod. In this embodiment, there is only one hot chamber 9 in the steam engine.

When one of the hot pistons 6 is at or close to the bottom of its range of movement, an inlet water valve 10 opens to allow entry of water into the bottom of the hot chamber 9. The valve 10 is then closed, and the water is heated from a heat source 7 so as to vaporised into steam. The steam then pushes the piston 6 upwards and turns the crank 31.

When the hot piston 6 moves downwards, an exhaust steam valve 12 opens to allow the steam to escape from the hot chamber 9. This valve 12 closes and the inlet valve opens when the hot piston 6 is towards the bottom of its range of travel.

The condensing steam engine includes a cold chamber 15 within which a cold piston 14 moves reciprocally. The cold piston is connected to the crank 31 via a connecting rod arrangement including a first connecting rod, a pivoting arm, and a second connecting rod. The pivoting arm pivots around a pivot point 33. The crank 31 is arranged to have two ends at 180° with respect to each other so that the steam engine pushes the crank 31 during the first stroke, and the condensing steam engine turns the crank 31 over the next 1800 as the steam condenses. Thus, the steam engine operates one stroke and the condensing steam engine drives the second stroke.

It is necessary to have a pivoting arm 32 in the connecting rod between the cold piston and the crank 31 so that the crank is turned through a first rotation of 1800 by the steam engine, and by the opposite 1800 by the condensing steam engine. It will be noted that the pivoting arm 32 is pivoted quite close to one end to compensate for the short stroke of the cold piston 14. It will be recalled from Figure 1 that the cold chamber and cold piston 14 are relatively large and flat with a short stroke to aid cooling via the cooling system 5. This may also be taken account of in the offset of the crank which might be smaller on the condensing steam engine side compared with that on the steam engine side.

The embodiment also includes the steam reservoir I in a very similar arrangement as that shown in Figure 1, and so we will not repeat the description of it again here. The arrangement by which the condensed water is collected in the condensed water reservoir 19 is also substantially the same as that disclosed and described in Figure 1.

Referring now to Figure 3, two combined steam engine and condensing steam engines are shown. The first of the pair are connected to one side of a crank 40, and the other of the pair are connected to the other side of the crank 40. Each side of the crank is 180° out of phase with the other side, so that the two combined steam engine and condensing steam engines are out of phase with each other. Apart from this, the pair of combined engines are identical.

Each of the combined engines are generally constructed in a similar way to that shown in Figures 1 and 2. The main difference is that no steam reservoir is included.

The left hand of the combined steam and condensing steam engines will be described Operation of the other of the pair is identical. The steam engine includes a hot chamber 9 and a hot piston 6 which moves reciprocally within the hot chamber 9. The hot piston 6 includes a connecting rod which is connected to the crank 40. As the piston 6 moves up and down, the crank 40 is rotated around its axis. When the hot piston 6 moves towards the bottom end of its extent of travel, an inlet water valve 10 is opened to allow water to enter the hot chamber 9. The inlet water valve 10 is then closed and the water heated by the heat source 7 so that it vaporises and pushes the hot piston 6 upwards to turn the crank 40. Once it is towards the top of its extent of movement, a valve 42 is opened to allow the steam from the hot chamber 9 to be exhausted via passage 41 as the hot piston 6 descends. Once the piston 6 has dropped, the valve 42 is closed and the inlet water valve 10 is opened again to allow entry of more water.

The steam is exhausted from the hot chamber 9 to the cold chamber 15, and as it enters the cold chamber 15, the cold piston 14 is raised. As the cold piston 14 is raised, the connecting rod lifts, and because of the pivoting rod 32, the crank drops.

The pivoting rod 32 pivots around a pivots point 33. The cold chamber and/or the cold piston 14 is cooled by a cooling system 5, and the steam condenses creating a partial vacuum beneath the cold piston 14 and causing it to drop. Towards the bottom of its extent of movement, electromagnets are switched on to cause the cold piston 14 to be lowered to its lowest extent, and to expel the condensate water. The dropping of the piston 14 causes the crank 40 to be pushed up by the effect of the condensing water driving the crank. It should be noted that the use of electromagnets here is optional.

It will be appreciated that the power stroke of the steam engine and the power stroke of the condensing steam engine coincide in pushing the crank 40 upwards. This is why a second combined steam engine and condensing steam engine are required on the opposite side of the crank out of phase with the first. By arranging it in this way, the passage 41 between the steam engine and the condensing steam engine is very short and reduces heat losses occurring as the steam passes from the hot chamber 9 to the cold chamber 15.

The condensed water is collected in the condensed water reservoir 19.

In common with the embodiment shown in Figure 2, the crank arm of the connecting rod has its pivot 33 displaced towards one end because the stroke of the cold piston 14 is much less than the stroke of the hot piston 6, and this is required to compensate for that difference. The surface area of the cold chamber is large to aid cooling of the steam.

Figure 4 shows a variant of the third embodiment in which both the hot piston 6 and the cold piston 14 drive the crank 40; but instead of being separately connected to the crank 40, they are jointly connected. The hot piston 6 includes a hot link 43, and the cold piston 14 has a cold link 44 extending from it. The hot link 43 is connected to the crank 40 via a pivoting connection 46 and a further connecting arm 45. The cold link 44 is connected to the pivot 46 via a pivoting arm 47.

In operation, as the hot piston is driven upwards by the expansion of water into steam, the crank is pushed into its upper position. At the same time, the cooling steam within the cold chamber 15 condenses and the cold link 44 is pulled down, and that force is converted by the pivoted rod 47 to assist in raising the connection link 45. Thus, extra torque is generated in the crank by the output movement of the connecting link 45 by both the hot piston 6 and the cold piston 14. As before, the hot piston 6 drops forcing the steam into the cold chamber 15 ready for the next driving cycle. The four valves 10, 11, 12 and 17 are computer controlled in order to allow operation of the device.

Cooling of the cold chamber 15 is carried out by the cooling system 5. Alternatively, the valves could be controlled by a mechanical control system.

It will be appreciated from the drawings that the inlets and outlets to the hot and cold chambers 9, 15 are to the base of the chambers. In many circumstances, this will be better than inlets and outlets to the side of the chamber, particularyin view of the likelihood of the piston covering the inlet or outlet.

A fourth embodiment will now be described with reference to Figures 5 and 6 which show this embodiment in two positions. Again, the embodiment is a combined steam engine and condensing steam engine, but to make it simpler and more compact, the hot chamber and the cold chamber are on opposite sides of two linked pistons. The combined steam engine and condensing steam engine is shown generally with reference 50. It includes a hot chamber 51 and a cold chamber 52. A first piston 53 moves reciprocally within the hot chamber 51. In Figure 5, both pistons are at their bottommost positions and the hot chamber is almost empty except for water which is directed into it via a inlet water valve 54. The cold chamber 52 is at maximum volume containing steam. At this point, a heat source heats the water in the hot chamber 51 which expands as it turns to vapour and pushes the first piston 53 upwards. At the same time, the cold chamber 52 cools the steam within that chamber causing it to condense and to create a low pressure within the cold chamber 52. This draws the second piston upwards so that the linked pistons are effectively driven on both sides.

Since the first and second pistons are effectively linked by the presence of a fluid between the two of them, the movement of the second piston 56 applies an upward pressure to the first piston 53. The first piston 53 is connected via a connecting rod to drive a crank.

Once the pistons are in their uppermost positions, they will drop again, and steam will be released from the hot chamber 51 via an exhaust steam valve 55 and the steam is directed into the cold chamber 52 via an inlet steam valve 57. In this case, there are two inlet steam pipes leading from the hot chamber to the cold chamber, but a single inlet steam pipe or more than two inlet steam pipes may be used. The diameter of these steam pipe or pipes are relatively large to permit the passage of the steam.

Since the combined system shown in Figures 5 and 6 both create the power stroke at the same time, it may be necessary to have two units connected to the crank which are out of phase with each other.

It will also be appreciated that the water extracted from the cold chamber will be directed into a condensed water reservoir 58 where it can be recycled and reused by being fed into the hot chamber 51.

Claims

Claims 1. A combined steam engine and condensing steam engine comprising: a steam transfer pipe between the steam engine and the condensing steam engine; and a steam reservoir in the steam transfer pipe.
2. A combined steam engine and condensing steam engine according to claim 1, wherein the steam reservoir includes a container and a piston-like lid movable within the container.
3. A combined steam engine and condensing steam engine according to claim 2, wherein the steam reservoir further comprises a rod connected to the piston-like lid which is movable to increase and reduce the volume of the steam reservoir by moving the piston-like lid, and a motor attached to the rod for moving the rod.
4. A combined steam engine and condensing steam engine according to claim 3 further comprising a controller for controlling the motor.
5. A combined steam engine and condensing steam engine according to claim 4, further comprising a pressure sensor for detecting the pressure of steam within the steam reservoir.
6. A combined steam engine and condensing steam engine according to any one of the preceding claims, wherein the steam reservoir is thermally insulated.
7. A combined steam and condensing steam engine according to claim 1, wherein the steam reservoir includes an expandable body.
8. A combined steam engine and condensing steam engine according to claim 7, wherein the expandable body includes a bellows.
9. A combined steam engine and condensing steam engine according to any one of the preceding claims, further comprising a central processing unit arranged to control the volume of the steam reservoir and/or the speed of the steam engine and/or the speed of the condensing steam engine.
10. A combined steam engine and condensing steam engine according to any one of the preceding claims, wherein the steam engine and condensing steam engine are arranged to drive separate cranks.
11. A combined steam engine and condensing steam engine according to any one of claims I to 9, wherein the steam engine and condensing steam engine are arranged so as to drive the same crank.
12. A combined steam engine and condensing steam engine according to claim 11, wherein the steam engine and condensing steam engine are arranged to drive opposite sides of the same crank out of phase with each other.
13. A combined steam engine and condensing steam engine comprising: a hot piston within the steam engine, a cold piston within the condensing steam engine; a crank; a connecting rod between the hot piston and the crank; and a connecting assembly between the cold piston and the crank, the connecting assembly including a pivoted aim
14. A combined steam engine and condensing steam engine according to claim 11, further comprising a pivot about which the pivoted arm turns, the pivot being located nearer one end of the arm than the other.
15. A combined steam engine and condensing steam engine according to claim 11 or claim 12, wherein the connecting assembly comprises a first rod connected to the cold piston, and a second rod connected to the crank, each of the first and second rods being connected to opposite ends of the pivoted rod.
16. A combined steam engine and condensing steam engine according to any one of claims 13 to 15 wherein the hot piston and the cold piston are connected to the same side of the crank.
17. A combined steam engine and condensing steam engine according to claim 16, further comprising a short steam pipe between the steam engine and condensing steam engine.
18. A combined steam engine and condensing steam engine to any one of claims 13 to 15, wherein the hot piston and the cold piston are connected to opposite sides of a common crank, out of phase with each other.
19. A combined steam engine and condensing steam engine according to claim 18, further comprising a steam reservoir between the steam engine and the condensing steam engine.
20. A combined steam engine and condensing steam engine comprising: a hot piston, a cold piston; a crank; and a body defining a hot chamber within which the hot piston moves and a cold chamber in which the cold piston moves, the hot and cold pistons being connected to each other to jointly drive the crank.
21. A combined steam engine and condensing steam engine according to claim 20, wherein the pistons are fluidly connected to each other.
22. A combined steam engine and condensing steam engine according to claim 20 or claim 21, wherein the hot chamber and the cold chamber are axially aligned.
23. A combined steam engine and condensing steam engine according to any one of claims 20 to 22, wherein the hot and cold chambers are connected.
24. A combined steam engine and condensing steam engine according to any one of claims 30 to 23, wherein one chamber leads into the other.
25. A combined steam engine and condensing steam engine according to any one of claims 20 to 24, further comprising a connecting rod connected to one of the pistons.