DE430554C - Piston steam engine - Google Patents

Description

Piston steam engine. The invention is partially or Complete replacement of what remains in the cylinder of the ordinary steam engine and afterwards compressed steam versus superheated steam, in the subsequent substitute steam or called purge steam. The purpose of the replacement is to achieve high compression temperatures, through which the innermost layers of the cylinder, especially the surrounding surfaces the harmful space, shortly before the entry of the live steam, are strongly heated, in order to keep the harmful effects of the internal heat exchange as low as possible. The live steam can be overheated or saturated. The. Steam exchange takes place here, similar to internal combustion engines, either in four-stroke cycles or in two-stroke.

The invention is applicable to both machines with condensation as with acceleration or with increased counter-pressure and -; however for single-cylinder machines as for compound machines.

Fig. I shows a single-cylinder nascbine with condensation, which works according to the two-stroke process. When the piston goes down, the processes correspond to those of a normal steam engine, ie first filling, then expansion and pre-flow take place. The outlet valve a is opened at the pre-flow point. After the pressure equalization between the cylinder and the condenser k has taken place more or less completely, the flushing valve s is opened. The flushing takes place with the exhaust valve left open, during which the steam remaining in the cylinder is replaced by superheated steam. To expel the old steam from the steam cylinder, the pressure of the replacement steam must be slightly higher than the pressure in the condenser k. The higher pressure can be generated or obtained by various means explained below. A piston flushing pump, as is common in two-stroke internal combustion engines, should be assumed here. The flushing pump p sucks in vacuum steam through the nozzle c of the exhaust steam pipe and drives it through the superheater after the flushing valve.

The control organs are drawn in Fig. I in the position in which they are in the process of flushing; also is the path that the substitute steam takes the flush takes, entered.

After the flushing is complete, the outlet valve a and the flushing valve s are closed, either simultaneously or one after the other. The subsequent closure of the flush valve has the consequence that part of the steam is pushed back into the superheater or into a Naclikammer in the same. This process, which is called the push-back process, ensures that the pressure does not rise as high in the case of a long compression path caused by the early closure of the outlet element. The pushback procedure can e.g. B. recommend when the inlet member f and the outlet member a are controlled jointly by a gate control (conveyors) by the compression paths for small fillings are very large in this type of control. But it is more suitable for machines with an exhaust than for machines with a condenser. When controlling the outlet through the working piston with cylinder slots and severely restricted harmful space (Fig. 2), it is also recommended for machines with condensation.

The flushing pump does not have to be a piston blower, it can also be a centrifugal fan or a jet fan. When the driving steam for If the jet fan is too hot, it will be useful after the superheater for about i switched on. It then sucks the vacuum vapor from the condenser through the superheater through.

The flushing pump can also be avoided entirely if the flushing steam is taken from the steam cylinder by tapping at a time when the pressure in the steam cylinder is even higher than in the condenser. For such tapping devices there are models for feedwater preheating that can be used for the task at hand; It is also conceivable, given sufficiently large cross- sections, to branch off the steam for flushing from a tapping device intended for feed water preheating.

The steam for the purge can also be taken from any other available source which supplies steam of sufficient pressure. Fig. 2 shows the invention in application to a machine with control of the outlet by the working piston, which shortly before the end of the stroke releases a slot in the cylinder wall and closes it again in the same position when it declines. - This type of control is commonly used in two-stroke internal combustion engines. For entry of the superheated Ersatzdami) fes a besondere. flush valve is s provided.

After the expansion has ended, advance occurs at the moment in which the piston edge passes over the first edge of the slot. The pressure drop and a more or less perfect pressure equalization between the cylinder and the condenser then occurs first. Only after this is reasonably completed, (las flush valve's open and there is an overheated vacuum vapor which is very well done and won, as is explained in the arrangement of Figure i;. I is the rinsing time considerably shorter because the flushing process is finished when the outlet flash is closed again when the piston retracts. If the flushing valve then remains open, backward thrust occurs in the superheater. The just described backward thrust process is then present, by means of which excessive compression is avoided actual compression in the cylinder only begins when the purge steam valve is closed.

In the Dai-npfdiagranim of Fig. 2 it is assumed that on the way 4-5 push back through the flush valve into the superheater takes place.

The functions of the cylinder slot and the flushing valve can also be interchanged and the replacement steam can enter through the cylinder slot a and the old steam can escape through the organ s. * Then the latter regulates the beginning of the compression as a normal outlet organ; Rückschtib does not take place.

However, the organ s can also be omitted entirely and instead, as is often the case with two-stroke combustion engines, a second slot can be arranged for the entry of the substitute steam, which is also controlled by the working piston and opened a little later by it and accordingly earlier is closed than the outlet port. In this case, of course, the back thrust method is not applicable, one is bound to the long compression path here.

The arrangements Fig. I and: 2 initially apply to machines with condensation; but with minor modifications they can also be used for machines with exhausts. The particular for the substitution steam is sucked then either by means of a scavenge pump from the exhaust pipe or a connected thereto collection chamber and passes through the superheater Ü Ge, or it is gewoilnen by tap and supplied to the 'Cberbitzer from the tapping point without flushing pump.

Instead of the valves, which are assumed in Figs. I and 2, other control devices can be used both for the main control and for the flushing control. In the case of double-acting machines, the usual 'mussel slide' is also conceivable; except him Spülorgan for the entry of Spüldampfes is required even for each cylinder side that you can ever mounted at the end of the two sides of the cylinder. But it is also possible to introduce the rinsing steam in the middle through a cylinder slot. With a correspondingly long piston, this slot can control the flushing inlet on both cylinder sides; with a piston of normal length, a special, twice-opening control element must be connected upstream of the slot.

If the machine, no matter what type of control it is provided with is, is double acting, is generally the superheater and the flushing pump for both sides be in common. The same applies to multi-cylinder steam engines a common superheater and a common flushing pump with corresponding branching and merging, - provide the connections. With single-acting machines the scavenging pump can also be designed as a crankcase pump, as is often the case with single-acting small combustion engines is common. In this case as many irrigation pumps are required as there are cylinders. One becomes them but let work on a common line.

Fig. 3 shows a single-acting steam engine with exhaust and steam exchange according to the two-stroke process with a mussel piston valve (fa). Since it only has to control one side, the mussel piston valve is designed on one side. It controls the inlet and outlet and is shown in the illustration set to outlet. The flush inlet member, which is also required, is also shown open, so that the flushing process is shown. The scavenging pump, not shown, removes exhaust steam through the extraction line e from a collecting container m of the exhaust line in order to then introduce it through the superheater U to the scavenging steam inlet element s.

You can also use the special flushing device leave out and Introduce the flushing nozzle through a ZN-linder slit, which is just before the end of the process of the piston is opened.

Fig. 4 shows in principle a four-stroke steam engine with steam exchange. In the four-stroke cycle, the flushing pump itself is omitted because the steam cylinder itself, with the two added strokes, causes the replacement by expelling the old steam and sucking in the superheated steam. The process is as follows in an exhaust engine: During the first stroke, filling takes place through the inlet element f, then expansion and pre-flow as in a normal steam engine. On the second stroke, the used steam is expelled without (let the steam be compressed. On the third stroke, part of the used steam is sucked in from the exhaust line through a superheater ü ; on the fourth stroke, this steam is compressed; it reaches a very high level Temperature.

If, because of the long compression path, it is to be expected that the final compression pressure If the inlet pressure exceeds or otherwise rises undesirably high, the replacement steam inlet element remains still open during part of the fourth stroke, so that backward thrust into the superheater takes place, just as it is explained in the case of the two-stroke.

It can be depending a special organ vorvorgesehen for the outlet and the replacement steam inlet. However, in order to keep the harmful spaces and surfaces small, it is more advisable to provide only one element sa for both tasks and to connect a switching element it which is switched over to sucking in the substitute steam after the end of the second stroke. In this position it is drawn in the formation of waste, while the position in dashed lines to the outlet. Fig. 4 is drawn for the satellite stroke with the piston moving to the right. The illustration is drawn for a machine with condensation. With the third stroke and before with the pre-flow, the steam flows off into the condenser k , whereby the switching element is to be thought of in the dashed position; During the fourth stroke, after the switching element has switched to the position shown, the piston sucks in steam from the capacitor voltage from the exhaust pipe through the superheater U.

about the heat input, the superheater size, the more achievable. Temperatures and the thermal economic success to be expected from the invention can be said as follows: The amount of substitute steam which is to be heated is small compared to the amount of filling steam. An approximate picture is the ratio of the size of the harmful space to the size of the filling clamp volume. When the compression goes up to the inlet pressure and the harmful space z. B. 4 v. H. of the stroke volume and the filling 16%. H., the volume of compressed replacement steam is % of the filling steam at the same high pressure. Since the temperature of the compressed replacement steam is considerably higher than that of the filling steam, even if the latter is severely overblown, the specific weight of the replacement steam in the harmful space is considerably lower than that of the filling steam. Thus, in the example chosen, the weight of the substitute steam is considerably less than% of the filling steam. The heat consumption in the event of overbeat and the necessary size of the superheater compared to a superheater, which goes through the machine throughout, are therefore correspondingly small. Steam has to overheat, as is the case with e.g. B. the case with Z-wiper superheaters of compound machines -st.

The C overheating of the substitute steam need not be high, even if high compression end temperatures are to be achieved. For example, steam reaches 0.2 atmospheres. Initial pressure and 2ool initial temperature when compressing to 10 atm., Calculated adiabatically, a temperature of about goo0 (with lower initial pressure [o, i Atm.1 and higher initial temperature [: 25o '] even above i --oo 0).

In the case of low-pressure cylinders of compound machines, which are particularly suitable for the process because the thermodynamic efficiency of the same is still very poor even in modern machines due to the heat exchange losses, the temperature does not reach this level because of the low final compression pressure, but at least (for 2oo ' Initial temperature and the same initial pressure as before) with compression to 2 Atrn. still 530 ', also calculated adiabatically. However, it does not present any difficulties, even with indirect overheating by means of live steam of 350 ', significantly higher initial temperatures than 2oo' for such purposes.

For exhaust machines with an initial compression pressure of 1.2Atm. and a compression end pressure of i2, Atrn. is reached with an initial temperature of 25o1, which corresponds to an excess temperature above saturated steam temperature of only 146 ', a temperature of over 600 '.

The high compression temperaturesa only occur towards the end of the Compression on and divide especially the innermost layer the walls surrounding the harmful space with just before the fresh filling steam occurs, so that there is hardly any time left for the warmth, after the deeper layers to wander the wall. This eliminates the very significant static losses greatly diminished.

The sliding surfaces are close apart from the sliding surfaces the cylinder ends, not exposed to high temperatures. The sliding surfaces on End iber gaim shortly after the occurrence of high temperatures from the flask run over and thus protected, so that there are no difficulties for lubrication of the cylinder surface area. The control organs used for steam exchange are traversed by steam at a low temperature. Overheating of the dishwashing bowl, (Substitute steam). Overheating occurs in machines that are connected to the boiler are (locomotives, locomotives) or are very close to it (ship engines), am best by the flue gases of the boiler. If the machines with Condensation work, the conditions are in a thermal economic relationship very cheap; because the initial temperature of the vacuum vapor is very low, and it can cialier the superheater for the purge steam when using the countercurrent behind the last boiler pass (in the smoke chamber), where it shows the smoke gas temperature exploits. If the steam engine is not closely related to the boiler, , indirect heating of the superheater with fresh steam is recommended be, for which examples are given in the case of the superheaters for intermediate steam; but it should be noted that for the present purposes also the overheating with not overheated fresh steam comes into question, since its saturation temperature is essential higher than that of the vacuum vapor. The rule, however, will be the overheating of the Create flushing steam using superheated live steam.

Regulation (1 e s K orn pr e ss i on s -dru ck- e s.

It can prove useful to keep the compression pressure at a constant level in the event of any changes in the withdrawal pressure of the purge steam or other influencing factors, or to prevent a certain level of the final compression pressure from being exceeded from time to time. In these cases the purge steam is throttled when the purge steam pressure increases before it enters the cylinder. The restriction can be obtained by a suitable device, if necessary with the aid of an auxiliary power gear (servo motor) can be introduced into automatic Abbängigkeit from the space in front of the entry into the cylinder prevailing pressure overall. For devices for automatic regulation of the steam pressure by throttling the steam supply, there are models in other areas. When the Spfildampf is artificially increased by a jet apparatus, occurs suitably in place of the modified throttling of the flushing steam regulating the Triebdampfzufluhr, which may also be automatically depending on the circumstances.

Claims (2)

PATENT APPROVAL: i. Piston steam engine with high compression temperature, characterized in that the remaining in the steam cylinder after the advance has taken place Steam is swapped for superheated steam before compression begins. 2. Two-stroke steam engine according to claim i, characterized in that superheated steam is introduced into the cylinder with the outlet (a) open. 3. Four-stroke steam engine according to claim i, characterized in that during the third stroke, after the old steam is pushed out in the second stroke, steam is sucked in from the exhaust pipe through a superheater (ii) and is compressed in the fourth stroke. 4. Steam engine according to claim i to 3, characterized by the pushing back of part of the superheated scavenging steam introduced into the cylinder into the superheater or a collecting space thereof. 5. Device for controlling the compression of a steam engine according to claim i to 3, characterized in that the pressure of the scavenging steam before entering the cylinder is reduced by throttling the scavenging steam supply line or is changed by changing de r motive steam supply of a compressor for the scavenging steam.