US3669571A - Tandem,free-piston machine - Google Patents

Tandem,free-piston machine Download PDF

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Publication number
US3669571A
US3669571A US887637A US3669571DA US3669571A US 3669571 A US3669571 A US 3669571A US 887637 A US887637 A US 887637A US 3669571D A US3669571D A US 3669571DA US 3669571 A US3669571 A US 3669571A
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pistons
compressor
drive
groups
piston
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US887637A
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Henry Benaroya
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B71/00—Free-piston engines; Engines without rotary main shaft
    • F02B71/04—Adaptations of such engines for special use; Combinations of such engines with apparatus driven thereby
    • F02B71/06—Free-piston combustion gas generators per se

Definitions

  • the present invention relates to tandem, free-piston machines.
  • the invention relates more particularly, because it is in this case that its application seems to be most advantageous, but not exclusively, among these machines, to those intended for supplying one or several turbines.
  • free-plston machines include at least one group of compressor pistons comprising at least three compressor pistons, namely, at least two outer compressor pistons and at least one inner compressor piston, moving in respective compressor cylinders,
  • each group comprising two pairs of said drive pistons, the two pistons pairs working in two drive cylinders, arranged in alignment and parallal to the compressor cylinders, and the two drive pistons of each pair working in opposition slidably on the 7 3,669,571 Patented June 13, 1972 ice means of synchronisation being provided between the outer movable train constituted by the outer compressor pistons and the outer drive pistons, and the inner movable train reciprocating in opposition to the outer movable train and constituted by the inner compressor piston and the inner drive pistons,
  • a machine according to the invention will have a much smaller bulk than that of a conventional machine, that it would be simpler, more reliable, and that its power to weight ratio will be increased to a considerable degree.
  • the invention consists, apart from this principal arrangement, in certain other arrangements, which are used preferably at the same time and which will be more explicitly described below.
  • FIG. 1 is an axial section with a portion in external view of a first embodiment of a machine according to the invention
  • FIG. 2 is a view in cross-section along the line II-II of FIG. 1;
  • FIG. 3 is an axial section, on a larger scale, illustrating a constructive detail of the embodiment shown in 'FIG. 1; 7
  • FIG. 4 is a view in partial axial section of another embodiment of a machine according to the invention.
  • FIG. 5 is a section along the line VV of FIG. 4;
  • FIG. 6 is an end view from VI of FIG. 4; 7
  • FIG. 7 is a diagramamtic axial half-section of a machine constructed according to yet another embodiment of the invention.
  • FIG. 8, finally, is a diagrammatic transversal section of the machine shown in FIG. 7.
  • tandem, free-piston machine is characterised by the fact that it comprises.
  • compressor pistons -1 comprising at least three compressor pistons, namely, two outer compressor pistons 2a and Zn and at least one inner compressor piston 2b, moving in the compressor cylinders, 3a, 3n, 3b respectively,
  • each group of drive pistons 4a, 4b being arranged so that the two outer drive pistons 7 are rigidly fixed respectively to the outer compressor piston 2a and to the outer compressor piston 2n, and the two inner drive pistons 8 are rigidly attached to the inner compressor piston 2b through a linking element 9, the outer compressor piston 2a being connected to the outer compressor piston 2n through a central rod 10 conjugating, in both directions, the movements of these outer compressor pistons 2a and Zn and the outer drive pistons 7, the two groups of drive pistons 4a, 4b being arranged symmetrically around the said central rod 10, the above-said linking element 9 being mounted slidably around the above-said central rod 10, synchronising means 11 being provided between the outer movable train constituted by the outer compressor pistons 2a and Zn and the outer drive pistons 7, and the inner movable train constituted by the inner compressor piston 2b and the inner drive pistons 8.
  • peripheral rods which would ensure up to the present the connection between the outer compressor pistons of the group of compressor pistons are eliminated, this connection being ensured by a mechanical element (central rod) to which may be given sufiicient dimensions to avoid any risk of vibrations and of bending, and which it is possible to guide efliciently.
  • compressor cylinders of a same group of compressor pistons can be aligned, as will be seen in the description which follows, or displaced angularly around the central rod, especially for constructional reasons.
  • the machine comprises a single group of compressor pistons 1 comprising three compressor pistons, namely, two outer compressor pistons 2a and Zn and an inner compressor piston 2b, moving in aligned compressor cylinders, 3a, 3n and 3b respectively, the inner compressor piston 2b constituting the linking element 9 and having, in its central part, an orifice 12 enabling its sliding around the central rod 10, the diameters of the three above-said compressor pistons 2a, 2b and Zn being such that their respective working surfaces are equal between themselves.
  • This machine can then advantageously be arranged in such manner that the work of compression of each of ,the three compressor pistons 2a, 2b and Zn in their respecone exhaust valve 26 and by at least one delivery valve 27.
  • each variable volume chamber 25 was served, as regards the exhaust, by a combination of an exhaust valve 26 situated in an annular chamber 28 and exhaust ports 29 communicating the annular chamber 28 with the variable volume chamber 25 under consideration.
  • this machine includes more than two groups of drive pistons; as shown in FIGS. 1 and 2, it includes three groups of drive pistons 4a, 4b and 40 arranged regularly around the central rod 10, at angular intervals of 120.
  • synchronising means 11 provided between the outer movable train (outer compressor pistons 2a and Zn and outer drive pistons 7) and the inner movable train (inner compressor piston 2b and inner drive pistons 8) are constituted by a rack 31 rigidly fixed to the compressor piston 2a or 2n, by a rack 31 rigidly fixed to the inner compressor piston 2b, and by a gear wheel
  • a rack 31 rigidly fixed to the compressor piston 2a or 2n
  • the machine includes several groups of compressor'pistons 1a, 1b, arranged parallel and symmetrically around compressor pistons 2a and the outer compressor pistons 2n of these groups of compressor pistons being co-axial with the aforesaid central axis 13, the connecting element 9 'having'acentral portion 14 mounted slidably around the central rod 10, and arms 15 connecting the said central portion -14,'on the one hand, to inner compressor pistons 2b of these groups of compressor pistons, and, on the other hand, to the inner drive pistons 8 of the groups ofdrive pistons.
  • the central rod 10 comprises, at each of its ends, a cruciform part34 provided accordingly with arms 35 according as the machine includes "groups of compressor pistons 1a, -1b and groups of drive pistons 4a, 4b, each of these arms 35 connecting the said central rod 10 to an outer drive piston 7 or to an outer compressor piston 2a or 2n, according to the side of the machine considered.
  • this machine includes,
  • each group of compressor pistons 1a and 1b two outer compressor pistons 2a and Zn and two inner compressor pistons 2b and 2c, these four compressor pistons 2a, 2b, 2c and Zn moving in the compressor cylinders, which can be aligned or displaced angularly around the central rod 10 (especially for constructional reasons), 3a, 3b, 3c and 3n respectively, the two outer compressor pistons 2a and Zn of the group being rigidly fixed to the central rod 10 through cruciform parts 34 with arms 35, the two inner compressor pistons 2b and 2c of the group being both rigidly fixed, through the connecting element 9 constituted by its central portion 14 and its arms 15, to the inner drive pistons 8 of each of the four groups of drive pistons 4a, 4b, 4c and 4d.
  • This machine can advantageously be arranged so that the work of compression of the compressor pistons 2a, 2b, 2c and 2n in their respective compressor cylinders 3a, 3b, 3c and 3n is efiected in both directions, the aforesaid compressor pistons 2a, 2b, 2c and 221 being hence doubleacting.
  • Each of the variable volume chambers 36 defined by a surface of a compressor piston and the corresponding side of the compressor cylinder is then served by at least one exhaust valve 37 and at least one delivery valve 38.
  • synchronising means 11 provided between the outer movable train (outer compressor pistons 2a and Zn of the two groups 1a and "1b, and outer drive pistons 7 of the four groups 4a, 4b, 4c'and 4d) and the inner movable train (inner compressor pistons 2b and 2c of the two groups 1a and lb'and inner drive pistons 8 of the four groups 4a, 4b, 4c and 4d) are constituted by a rack 39 rigidly fixed to one of the outer compressor pistons (for example through one of the arms 35), by a rack 40 rigidly fixed to one of the inner pistons (forexample through one of the arms 15), and by a gear wheel 41 mounted on a fixed axis 42 and constantlyin mesh with the two above-said racks 39 and 40 (FIG. 5).
  • the embodiment illustrated in FIG. 4 has the advantage of separating the mechanical functions (linking functions) and the thermodynamic functions (compressor functions) of the compressor pistons.
  • the inner compressor piston 2b ensures the mechanical linkage between the inner drive pistons 8, the outer compressor pistons 2a and 2n ensuring the mechanical linkage between the outer drive pistons 7.
  • Thesecompressor pistons must hence be calculated, on the one hand, to resist the forces generated by these mechanical linkages (which forces can be disturbed by possible irregularities in the operation of the groups of drive pistons), and, on the other hand, to ensure their work of compression (which work can be disturbed by possible jammings of the exhaust and/or delivery valves of the groups of compressor pistons).
  • the outer compressor pistons 2a and Zn, and the one or more inner compressor pistons 2b and 2c ensure only their work of compression, the mechanical linkages being ensured by the cruciform parts '34 with arms 35 or the linking element 9 with central portion 14 and arm 15, to which it is possible to give dimensions appropriate to their role without being obliged to take other factors into consideration.
  • the machine includes several groups of compressor pistons which are distributed in groups of compressor pistons in which the delivery pressures are at different levels, the groups of compressor pistons at equal levels of pressure being preferably arranged symmetrically around the central axis 13.
  • this machine includes,
  • each group of compressor pistons 1a, 1b, 1c and 1d of this machine may include two outer compressor pistons 2a and 2n and two inner compressor pistons 21) and 2c, these four compressor pistons 2a, 2b, 2c and 21: moving in aligned compressor cylinders 3a, 3b, 3c and 311 respectively, the two outer compressor pistons 2a and Zn of the group being rigidly connected to the central rod through the cruciform parts 34 with arms 35, the two inner compressor pistons 2b and 2c of the group being both rigidly fixed, through the linking element constituted by its central portion 14 and its arms 15, to the inner drive pistons of each of the four groups of drive pistons 4a, '4b, 4c and 4d.
  • This machine can then be advantageously arranged so that the work of compression of the compressor pistons 2a, 2b, 2c and 2n in their respective compressor cylinders 3a, 3b, 3c and 3n is eifected in both directions, the abovesaid compressor pistons 2a, 2b, 2c and 211 being hence double-acting and, preferably, mounted so that one outer compressor piston works in opposition with one inner compressor piston.
  • Each of the variable volume chambers 44 bounded by one surface of a compressor piston and the corresponding side of the compressor cylinder is then served by at least one exhaust valve 45 and at least one delivery valve 46.
  • the central rod 10 is guided in sliding bearings arranged in the bottoms of the compressor cylinders 3a, 3b and 311 traversed by'the said central rod 10.
  • the central rod 10 is surrounded by three tubular cross-pieces, namely,
  • passages 54 being provided to connect each of the two variable volume chambers 25 limited by the inner compressor piston 2b and the inner compressor cylinder 3b with the two annular spaces 55 and 56 bounded by the central rod 10 and the two outer tubular crosspieces 52 and 53.
  • a sliding sealing joint 57 constituted by segments, is then interposed, at the right of the inner compressor piston 2b, between the central rod 10 and the inner tubular cross-piece 51.
  • a pressure balance is thus maintained between the variable -volume chambers 25 where there must exist, 0perationally, the same pressure.
  • each of the two outer compressor pistons 2a and Zn is completed by three additional rods 58 each extending the rod of the corresponding outer drive pistons 7, these additional rods 58 sliding in slide bearings 59 arranged in the outer bottom of the outer compressor cylinder 3a or 3n considered.
  • the guidance of the central rod 10 with respect to the chassis 60 of the machine is ensured principally by two slide bearings 61 arranged in vicinity of the ends of the said central rod 10.
  • slide bearings 61 may be given a v slight conicity towards the exterior.
  • slide bearings 61 can also be mounted on balland-socket joints.
  • the machine according to the invention has a reduced bulk, a smaller weight of the movable train, an increased stroke frequency and a greater power to weight ratio.
  • Themachine according to the invention can work as a motor-compressor supplying compressed air or as an antigenerator supplying a gaseous mixture of compressed. air
  • a tandem, free-piston machine having inner and outer movable trains arranged respectively to reciprocate in synchronism in opposite directions, said machine comprising:
  • compressor pistons comprising each at least three compressor pistons, namely, at least two outer compressor pistons and at least one inner compressor piston moving in respective compressor cylinders, the compressor cylinders of each group being arranged in alignment to each other,
  • each group comprising two pairs of said drive pistons, each pair of the two drive piston pairs working in opposition in drive cylinders, the drive cylinders being arranged in alignment to each other and parallel to the compressor cylinders,
  • each group of compressor and drive pistons being arranged parallel and symmetrically around a central axis, I each group of drive pistons being arranged so that the outer drive pistons of the two drive piston pairs .are
  • the outer compressor and drive pistons being connected by-acentral rod coaxial with said central axis, said central rod sliding in fixed bearings, .and the inner compressor and drive pistons being connected by a linking element having a central part coaxially positioned around and spaced from the central rod over the entire length of said central part and arms connecting said central part, on the one hand, to the inner compressor pistons of said groups of compressor pistons, and, on the other hand, to the drive pistons of the groups of drive pistons.
  • a machine according to claim 1 wherein the groups of compressor pistons are distributed in groups of com- .pressor pistons in which the delivery pressures are at different levels, the groups of compressor pistons at equal pressure levels being arranged symmetrically around the central axis.
  • a machine according to claim 3 including at least one heat exchanger ensuring the cooling of the compressed gas between the groups of compressor pistons in which the delivery pressures are at different levels.
  • passages being provided to connect each of the two variable volume chambers, defined by the inner compressor piston and the inner compressor cylinder, with the two annular spaces, defined by the central rod and the two outer tubular cross-pieces,
  • a sliding sealing joint constituted by segments, being then interposed at the right of the inner compressor piston, between the central rod and the inner tubular cross-piece.
  • a machine wherein the guidance of the central rod is ensured by two sliding bearings arranged in the vicinity of the ends of said central rod, said two sliding bearings being arranged so as to give a certain degree of radial freedom to the guidance of the central rod.
  • a machine according to claim 13 wherein there is interposed, between the outer drive pistons and the arms of a cruciform part connecting said outer drive pistons to the central rod, elastic elements capable of transmitting additional forces due to possible irregularities of operation of the groups of drive pistons.
  • a machine according to claim 1 wherein is interposed, between the outer drive pistons and the arms of a cruciform part connecting said outer drive pistons to the central rod, spherical ball-and-socket joint devices capable of transmitting additional forces due to possible irregularities of operation of the groups of drive pistons.
  • a tandem, free-piston machine having inner and outer movable trains arranged respectively to reciprocate in synchroism in opposite directions, said machine comprising:
  • compressor pistons comprising each at least four compressor pistons, namely, at least two outer compressor pistons and at least two inner compressor pistons moving in respective compressor cylinders, the compressor cylinders of each group being arranged in alignment to each other,
  • each group comprising two pairs of said drive pistons, each pair of the two drive piston pairs working in opposition in drive cylinders, the drive cylinders being arranged in alignment to each other and parallel to the compressor cylinders,
  • said groups of compressor and drive pistons being arranged parallel and symmetrically around a central axis
  • each group of drive pistons being arranged so that the outer drive pistons of the two drive piston pairs are rigidly attached respectively to the outer compressor pistons, and the inner drive pistons of the two drive piston pairs are rigidly attached to the inner compressor pistons,
  • the outer compressor and drive pistons being connected by a central rod coaxial with said central axis, said central rod sliding in fixed bearings, and the inner compressor and drive pistons being connected by a linking element having a central part, a support coaxially positioned around and spaced from said central rod, said central part being mounted slidingly on said support, and arms connecting said central part, on the one hand, to the inner compressor pistons of said groups of compressor pistons, and, on the other hand, to the inner drive pistons of the groups of drive pistons.
  • a tandem, free-piston machine having inner and outer movable trains arranged respectively to reciprocate in synchronism in opposite directions, said machine comprising:
  • each group of compressor pistons comprising each of at least four compressor pistons, namely, at least two outer compressor pistons and at least two inner compressor pistons moving in respective compressor cylinders, the compressor cylinders of each group being arranged in alignment to each other, at least two groups of drive pistons, each group comprising two pairs of said drive pistons, each pair of the two drive piston pairs working in opposition in drive cylinders, the drive cylinders being arranged in alignment to each other and parallel to the compressor cylinders, said groups of compressor and drive pistons being arranged parallel and symmetrically around a central axis, each group of drive pistons being arranged so that the outer drive pistons of the two drive piston pairs are rigidly attached respectively to the outer compressor pistons, and the inner drive pistons of the two drive piston pairs are rigidly attached to the inner compressor pistons, the outer compressor and drive pistons being connected by a central rod coaxial with said central axis, said central rod sliding in fixed bearings, and the inner compressor and drive pistons being connected by a linking element having a

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
US887637A 1968-12-27 1969-12-23 Tandem,free-piston machine Expired - Lifetime US3669571A (en)

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FR181237 1968-12-27

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US (1) US3669571A (de)
JP (1) JPS492206B1 (de)
AT (1) AT325344B (de)
BE (1) BE743552A (de)
CA (1) CA927345A (de)
CH (1) CH520866A (de)
DE (2) DE6949804U (de)
DK (1) DK130085B (de)
ES (1) ES374935A1 (de)
FR (1) FR1601540A (de)
GB (1) GB1296713A (de)
LU (1) LU60074A1 (de)
NL (1) NL167753C (de)
SE (1) SE352137B (de)
SU (1) SU409436A3 (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4274327A (en) * 1979-02-16 1981-06-23 Olsgaard Orin J Expansible chamber device
US4412476A (en) * 1979-05-07 1983-11-01 Henry Benaroya Tandem machine with opposed free pistons
US4678407A (en) * 1979-06-25 1987-07-07 Henry Benaroya Multi-tandem free piston machine
WO2003078810A1 (en) * 2002-03-15 2003-09-25 Advanced Propulsion Technologies, Inc. Engine with power generating capability
US20060124084A1 (en) * 2003-06-25 2006-06-15 Advanced Propulsion Technologies Inc. Internal combustion engine
US20060138777A1 (en) * 2003-06-25 2006-06-29 Peter Hofbauer Ring generator
US20100186583A1 (en) * 2009-01-28 2010-07-29 Jackson Lumber Harvester Company, Inc. Hollow double rod cylinder actuator
CN104329165A (zh) * 2014-10-17 2015-02-04 华侨大学 一种两缸四冲程液压自由活塞发动机
CN109281814A (zh) * 2018-10-18 2019-01-29 洛阳拖拉机研究所有限公司 可分离与结合的发动机用空气压缩机传动装置及传动方法

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5155609A (de) * 1974-11-11 1976-05-15 Sony Corp
FR2432089A1 (fr) * 1978-07-26 1980-02-22 Benaroya Henry Installation de production d'energie a generateur a pistons libres
FR2459366A1 (fr) * 1979-06-20 1981-01-09 Benaroya Henry Perfectionnements aux machines a pistons libres
DE3038680A1 (de) * 1980-10-14 1982-05-27 Johann B. 6530 Bingen Pfeifer Kolbenmaschine zur erzeugung von pressluft, kaelte u.dgl.
DE102011106574A1 (de) * 2011-06-16 2012-12-20 Gaby Traute Reinhardt Pumpeinrichtung

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4274327A (en) * 1979-02-16 1981-06-23 Olsgaard Orin J Expansible chamber device
US4412476A (en) * 1979-05-07 1983-11-01 Henry Benaroya Tandem machine with opposed free pistons
US4678407A (en) * 1979-06-25 1987-07-07 Henry Benaroya Multi-tandem free piston machine
US20060213466A1 (en) * 2002-03-15 2006-09-28 Advanced Propulsion Technologies, Inc. Internal combustion engine
US7255070B2 (en) 2002-03-15 2007-08-14 Advanced Propulsion Technologies, Inc. Internal combustion engine
US7383796B2 (en) 2002-03-15 2008-06-10 Advanced Propulsion Technologies, Inc. Internal combustion engine
US20050103287A1 (en) * 2002-03-15 2005-05-19 Peter Hofbauer Internal combustion engine
US20060201456A1 (en) * 2002-03-15 2006-09-14 Advanced Propulsion Technologies, Inc. Internal combustion engine
WO2003078810A1 (en) * 2002-03-15 2003-09-25 Advanced Propulsion Technologies, Inc. Engine with power generating capability
US7207299B2 (en) 2002-03-15 2007-04-24 Advanced Propulsion Technologies, Inc. Internal combustion engine
US20060138777A1 (en) * 2003-06-25 2006-06-29 Peter Hofbauer Ring generator
US20060124084A1 (en) * 2003-06-25 2006-06-15 Advanced Propulsion Technologies Inc. Internal combustion engine
US7469664B2 (en) 2003-06-25 2008-12-30 Advanced Propulsion Technologies, Inc. Internal combustion engine
US7728446B2 (en) 2003-06-25 2010-06-01 Advanced Propulsion Technologies, Inc. Ring generator
US20100186583A1 (en) * 2009-01-28 2010-07-29 Jackson Lumber Harvester Company, Inc. Hollow double rod cylinder actuator
CN104329165A (zh) * 2014-10-17 2015-02-04 华侨大学 一种两缸四冲程液压自由活塞发动机
CN109281814A (zh) * 2018-10-18 2019-01-29 洛阳拖拉机研究所有限公司 可分离与结合的发动机用空气压缩机传动装置及传动方法
CN109281814B (zh) * 2018-10-18 2024-02-13 洛阳拖拉机研究所有限公司 可分离与结合的发动机用空气压缩机传动装置及传动方法

Also Published As

Publication number Publication date
DE1964768A1 (de) 1970-07-02
NL6919362A (de) 1970-06-30
SU409436A3 (de) 1973-11-30
GB1296713A (de) 1972-11-15
JPS492206B1 (de) 1974-01-19
NL167753B (nl) 1981-08-17
DE6949804U (de) 1972-12-21
NL167753C (nl) 1982-01-18
CA927345A (en) 1973-05-29
ES374935A1 (es) 1972-02-16
AT325344B (de) 1975-10-10
DK130085C (de) 1975-05-26
BE743552A (fr) 1970-06-22
SE352137B (de) 1972-12-18
FR1601540A (de) 1970-08-24
CH520866A (fr) 1972-03-31
LU60074A1 (de) 1970-06-26
DK130085B (da) 1974-12-16

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