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Title:
VAPOUR TYPE POSITIVE-DISPLACEMENT COGENERATION UNIT
Document Type and Number:
WIPO Patent Application WO/2002/073005
Kind Code:
A1
Abstract:
A stream/vapour positive displacement cogeneration unit is composed of a partly modified motoric mechanism of a piston-type reciprocating rotational machine and of a stream/vapour working cylinder (10) with a double-acting piston (11), on which a hollow guide rod (1) is mounted with a sliding fit in a bearing (3) and in a stuffing box (4) fastened on a bottom head (15). Through the hollow guide rod (1) a piston rod (2) is running, whose one end is articulated to the piston (11) and the other end is articulated to amodified piston (5) of the piston-type rotational machine.

Inventors:
KLIR TOMAS (CZ)
STASTN JIRI (CZ)
Application Number:
PCT/CZ2002/000012
Publication Date:
September 19, 2002
Filing Date:
March 01, 2002
Export Citation:
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Assignee:
POLYCOMP A S (CZ)
KLIR TOMAS (CZ)
STASTN JIRI (CZ)
International Classes:
F01B17/04; F01B29/04; F01K11/00; F02B69/00; F02B75/00; F22B35/00; F02B1/04; F02B3/06; (IPC1-7): F01B17/04; F02B69/00; F02B75/00; F01B29/04
Foreign References:
US2514287A1950-07-04
US2212665A1940-08-27
US1045702A1912-11-26
CH286918A1952-11-15
Attorney, Agent or Firm:
Novotny, Jaroslav (Rímská 45 Praha 2, CZ)
Download PDF:
Description:
Vapour type positive-displacement cogeneration unit Technical field of the invention The invention concerns a vapour (gas) type positive-displacement cogeneration unit especially for small and medium capacities utilisable in connection with an electric power generating unit or as a direct prime mover of machines.

Background art A large plurality of communal and technical heat energy supply sources are represented by dislocated medium-pressure boiler units producing a moderately overheated steam at a gauge pressure approximately 1 to 1.5 MPa. This steam is supplied, after a reduction of its pressure, to a further communal or technological process utilization, while utilizing above all its condensing heat.

As a standard, its pressure is reduced by pressure reducing valves, thus effecting no quantitative change in that no heat energy gets lost. From the qualitative view, however, a pressure energy of the steam is lost without being utilized during said pressure reduction.

An increased attention has been paid to the utilization of the pressure difference during the pressure reduction of steam, vapour or gaseous medium. Development are undertaken in two directions, namely in using high r. p. m. back-pressure turbines and in using positive displacement steam/vapour engines. Turbines are used for the capacities of 100 to 200 kW, smaller capacities are solved as high-speed steam engines. Such cogeneration units serve either as a direct drive of machinery or as prime movers of electric power generators producing electric power.

From the very principle of replacing a standard pressure reduction using pressure reducing valves by rotational pressure reduction, e. g. by steam engines, it becomes obvious that, regardless of the C. O. P. of transforming the pressure energy to a utilizable work, the additional fuel expense, going at the cost of the final energy produced, always equals said energy if expressed in comparable physical units. Under this consideration the final effect is not affected by the magnitude of the transformation C. O. P. attained.

Known from the Czech patent specification No. 286 918 is a small-capacity cogeneration unit incorporated between a medium-pressure boiler and consumer inputs. This unit consists of a modified single or multicylinder mechanism of a diesel or ignition type inner combustion engine or compressor or alike. Each cylinder of said mechanisms has a special head comprising one filling channel and one exhaust channel. A hollow filling rotational slide valve type gear and a hollow exhaust rotational slide valve gear are fitted on each head. This concept comprises no piston rod and no crosshead guides. The modification of the basic mechanism consists in replacing the original engine head featuring a conventional valve gear with an special head featuring a slide-valve gear. Said cogeneration unit operates as a single- acting steam engine.

A drawback of most cogeneration units used up to date is in their relatively high prime cost, which often makes their payback period excessively long especially for small capacity units.

Disclosure of the invention The drawback as mentioned above, i. e. present high prime cost of a steam engine working as a positive displacement cogeneration unit or the loss of working capacity of steam, vapour or gas when its pressure is reduced by means of conventional pressure reducing valves, is remedied by using a positive displacement steam/vapour cogeneration unit incorporated into the system of a steam/vapour/gas pipeline instead of a pressure reducing valve.

The substance of the cogeneration unit according to the invention is utilizing a basic modified mechanism of an inner combustion ignition or diesel engine or compressor, from which the engine crankcase (block), the oil circulation system, the crank, conrod, piston and cylinder are mostly utilized. The oil circulation system is modified and limited to the function of lubrication of the crankcase mechanism including the cylinder and said modified original piston. The piston takes over the function of a crosshead and is modified so that the piston rod together with the conrod can be fitted into its original piston pin by an articulation joint. One or several working steam/gas cylinders with corresponding steam/gas inlet and outlet heads with a slide-valve steam/gas distribution gear are connected to the basic engine unit, modified in the said manner from a single or multicylinder engine, as a superstructure. A double-acting working piston runs in said cylinders. This piston is connected with the basic modified engine unit by a hollow guide rod and by a piston rod. The hollow guide rod is rigidly connected with the double-acting working piston while the other end of said hollow rod is free. The hollow guide rod guides the working piston and seals off at the same time the steam leakage and oil infiltration into the cylinder working chamber. The piston rod travelling in the guide rod is articulated in the working cylinder working piston and at the same time also articulated in the modified piston of the original engine unit. The piston rod transfers the reciprocating force from the working cylinder to the crank mechanism of the basic engine unit. Such preferred structure of a hollow guide rod and of the piston rod provides for a perfect guiding of the double-acting working steam piston in the cylinder and a long life expectancy of the guide bearing and of the stuffing box through both of which it passes. An articulated fitting of the piston rod compensates for all imprecisions between the guide axis of the modified piston of the original engine unit, i. e. between the axis of the guide of the modified piston (crosshead) and the axis of guide surfaces of the working steam piston. Both said axes thus become, under current tolerances, independent from each other. The advantage of such concept is in that basic components of mass-produced engines can be used. The hollow guide rod and the piston rod made according to the present invention compensate, above all in multi-cylinder types, any coaxiality deviations due to thermal dilatation, vibration and production inaccuracies, while perfectly sealing off the working chamber of the working cylinder against steam leakage and oil infiltration into the working cylinder.

The hollow rod and piston rod assembly enables to connect without any problems the basic engine unit with the steam-driven working section, and owing to the compensation of any and all possible other coaxiality imprecisions it also saves costs in assembling and manufacturing of the steam-driven working superstructure. A cogeneration unit built according to the invention represents an acceptable prime cost with a short investment payback period owing to the possibility of using a cheap mass-manufactured engine. It finds therefore a good application as a replacement for a pressure reducing valve even where a conventional steam engine or turbine are unrealistic for economic reasons. Such setup connected with a power generator in a cogeneration plant or in a gas pressure reduction step provides a cheap production of electric power.

Example of embodiment of the invention Fig. 1 schematically shows a sectional view of the cylinder of a multicylinder cogeneration positive displacement unit composed, according to the invention from modified components of a multicylinder internal combustion engine and of a steam/vapour driven working section. <BR> <BR> <P>After removal of the original head with a conventional valve gear a head 13 carrying an<BR> intermediate piece 14 is fitted on the cylinder 8. On the intermediate piece 14 a bottom head 15 of the distribution gear is mounted, carrying a cylinder 10 with an upper head 16 of the<BR> distribution gear, thus constituting a steam/vapour working section, in which a non-lubricated<BR> piston 11 is travelling. On the distribution heads 15, 16 a slide-valve distribution gear (not<BR> shown here) is fitted, actuated by means of a crankshaft 9. The reciprocating strokes of the<BR> piston 11 are transferred into a rotating motion by a piston rod 2 ; one end of which is fitted by<BR> means of head 20 on the pin 18 of piston 11. The other end of piston rod 2 carries a head 19,<BR> articulated together with a conrod head 7 on the pin 6 of a modified piston 5. Said modified<BR> piston 5 sliding in cylinder 8 plays the role of a crosshead. The piston rod 2 transferring the<BR> force from piston 11 onto the crankshaft 9 is situated in the cavity of a guide rod 1, whose one end is fastened on the double-acting piston 11, the other end being loose. The hollow rod 1 is fitted with slide fit in a bearing 3 and in a stuffing box 4, said bearing 3 being fitted in the bottom distribution head 15, on which also the stuffing box 4 is mounted.

As may be seen, the following parts of a standard internal combustion engine are utilized : the crankcase (block), the oil supply system, the crankshaft, the crank, a modified piston and the cylinder. The role of the oil supply system is limited merely to the lubrication of the crank <BR> <BR> mechanism including the cylinder and the piston. An articulated fit of piston rod 2 in piston<BR> 11 and in piston 5 provides for the compensation of any deviation of coaxiality between the<BR> axis of the guides for the modified piston 5 (crosshead) and the travel axis of the working<BR> steam/vapour piston 11 as determined by the hollow rod 1. Both said axes are, owing to the invention concept, independent from each other under current tolerances, which yields, especially for multicylinder models, also the compensation of deviations due to thermal dilatation, vibration and/or possible manufacturing tolerances.

The hollow guide rod provides for sealing off the steam/vapour working cylinder cavity while preventing at the same time oil from intruding into the oilfree working chamber of the cogeneration unit cylinder.

CLAIMS 1. A steam/vapour cogeneration unit composed of a partly modified motoric mechanism of a reciprocating piston-type rotational machine, and of a working steam/vapour cylinder with a double-acting piston, characterized in that on a cylinder (8) of a modified engine a head (13) carrying an intermediary piece (14) is fitted, on which a steam-driven working section is mounted, consisting of a bottom distribution head (15), a cylinder (10), an upper distribution head (16) and a double-acting working piston (11), on which a hollow guide rod (1) is fitted with sliding freedom in bearing (3), situated in the bottom distribution head (15) and in a stuffing box (4) also mounted in the bottom distribution head (15), while through the cavity of the guide rod (1) a piston rod (2) is running, whose one end is articulated by means of a head (20) to the pin (18) of the working piston 11 and the other end is articulated via head (19) to the piston pin (6) of a modified piston (5) also carrying the head of a conrod (7).

2. A steam/vapour positive displacement cogeneration unit according to Claim 1, c h a r a c- t e r i z e d i n t h a t the head (19) of the piston rod (2) is fitted on another pin situated in the modified piston (5).