US3292501A - Device including at least one cylinder with a piston-shaped body which is movable therein - Google Patents

Device including at least one cylinder with a piston-shaped body which is movable therein Download PDF

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Publication number
US3292501A
US3292501A US415980A US41598064A US3292501A US 3292501 A US3292501 A US 3292501A US 415980 A US415980 A US 415980A US 41598064 A US41598064 A US 41598064A US 3292501 A US3292501 A US 3292501A
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United States
Prior art keywords
piston
gap
cylinder
seal
cold
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Expired - Lifetime
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US415980A
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English (en)
Inventor
Verbeek Hendrik Jozef
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/14—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J1/00—Pistons; Trunk pistons; Plungers
    • F16J1/005—Pistons; Trunk pistons; Plungers obtained by assembling several pieces
    • F16J1/006—Pistons; Trunk pistons; Plungers obtained by assembling several pieces of different materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
    • F25B9/004—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being air

Definitions

  • the operating temperatures in the present device are lower than the temperature of the atmosphere, and a gap is present between the pistonshaped body and the cylinder which gap communicates at one side with the working space and is bounded at its other side by a seal provided between the piston-shaped body and the cylinder. Said seal in operation exhibits a temperature higher than that which prevails in the working space.
  • Known devices of the kind to which the present invention relates are, for example, cold-gas refrigerators, piston-expansion engines, cold compressors, etc.
  • the piston which varies the volume of the cold working space, usually has thin walls and a comparatively great length. This is to isolate the crank case from the working space and also to permit the seal between the piston and the cylinder to be established at the temperature of the atmosphere.
  • the piston and the cylinder exhibit a minimum difference in diameter at the seals.
  • the said known devices have, however, the disadvantage that a comparatively large amount of cold disappears through the walls of the gap and through the medium in the gap between the piston and the cylinder to the ambience, which constitutes a loss for these engines. This loss results in a cold leak and hence in a loss of output.
  • the said disadvantage may be overcome to a considerable extent by forming the wall parts of the piston-shaped body and/or of the cylinder which constitute the boundaries of the gap so that-the gap widens at least over part of its axialdimension towards the seal.
  • the gap widens in a direction opposite to that inknown devices and this surprisingly gives rise to a considerable decrease in the loss of cold.
  • the wall parts of the piston-shaped body and/or of the cylinder which parts constitute the boundaries of the gap a conical
  • the gap thus acquires a conical shape in the axialdirection, the maximum width of the gap being at the side of the seal.
  • the gap invariably has a very small width whichis dependent upon a plurality "ice of factors such as the stroke, the diameter and the length of the piston-shaped body, the temperature gradient occurring in the axial direction and the pressure and pressure variations occurring in the working space, number of revolutions, medium, etc.
  • the gap has a width between 0.1 mm. and 0.5 mm. at the side remote from the working space.
  • Another advantageous embodiment of the device according to the invention is characterized in that the wall parts which constitute the gap-bounding surfaces extend so that the width of gap at any point of the gap is proportional to a value which is less than, or equal to, the coefficient of thermal conductivity of the working medium at the temperature corresponding to this area in operation and higher than, or equal to, the square root of this coefficient of thermal conductivity.
  • the cold loss has been found to be very small with a gap the width of which varies in this manner.
  • a further advantageous embodiment of the device vaccording to the invention is characterized in that the narrow gap exhibits a relative eccentricity of not more than 20%
  • the device according to the invention is characterized in that an annular centering element is provided in the gap approximately at the area where the narrow gap opens into the working space, which element exhibits apertures regularly divided over its periphery and through which the gap communicates with the working space. Satisfactory centering of the piston in the cylinder is thus obtained in a simple manner so that additional loss of cold resulting from differences in the width of gap is avoided.
  • FIGURES l, 2 and 3 show, not to scale, several pistoncylinder combinations illustrating the shape of the walls of the gap;
  • FIGURES 4 and 5 are a sectional view and-a plan view respectively, of a cylinder-piston combination having .a centering ring between the piston and the cylinder;
  • FIGURES 6 and 7 are sectional views of two embodiments of a cold-gas refrigerator in which the gap between the walls of the displacer and the cylinder widened towards the hot space.
  • the reference numeral 1 indicates a cylinder in which apiston 2 is movable.
  • The'piston 2 is coupled by means of a connectingrod 3 to a driving mechanism (not shown).
  • the upper side of the piston 2 can vary the volume of a working space 4.
  • This working space may be, for example, the expansion space of a cold-gas refrigerator or a an expansion piston engine. Consequently, low temperatures prevail in the said space in operation.
  • the piston 2 comprises two portions 5 and 6, the portion 5 constituting the piston proper. Between the portion 5 and the cylinder 1 there is provided a seal 7, which may be formed as a gap seal, but it is alternatively possible to use piston rings, O-rings or a seal in the form of a rolling diaphragm.
  • the portion 6 of the piston (the piston cap) has a temperature which increases over its axial dimension towards the seal. This implies that the portion 5 of the piston andhence the seal exhibit a temperature higher than that which prevails in the working space.
  • a gap 8 exists between the portion 6 of the piston and the wall of the cylinder 1.
  • the piston portion 6 is made conical in shape so that the gap 8 becomes wider towards the seal.
  • the width of the gap is shown with much greater dimensions than is the case in practice.
  • the gaps actually have a width at the hot side which is of the order of magnitude from 0.1 mm. to 0.5 mm.
  • the gaps become narrower towards the cold side so that the width of the gap is very small at the area where the gap opens into the working space.
  • the coeflicient of heat conduction (A) of the working medium which may be, for example, hydrogen or helium, depends on temperature.
  • the coeflicient of heat conduction of the working medium is higher at a higher temperature than at a lower tempera ture.
  • the shape of the wall of the piston portion 6 is thus chosen so that for two arbitrary points A and B of the gap there applies:
  • the wall of the portion 6 is formed as part of a conical periphery with a straight generatrix, it is alternatively possible to form the said wall with a curved generatrix.
  • FIGURES 4 and 5 show the manner in which the piston 2 may be satisfactorily centered in the cylinder 1 by using a centering ring.
  • the centering ring designated by the reference numeral 10, has apertures 11 which are regulanly divided over its periphery. This affords the advantage that the working medium is divided over the gap very uniformly and this is advantageous as stated hereinbefore.
  • FIGURE 6 shows for illustrative purposes a cold-gas refrigerator.
  • This refrigerator comprises a cylinder 21 in which a displacer 22 and a piston 23 are adopted to move out of phase.
  • the displacer and the piston are connected through piston rods 24 and 25, respectively, to a driving mechanism (not shown).
  • the piston 23 can vary the volume of a compression space 26.
  • This space communicates through a cooler 27, a regenerator 28 and a freezer 29 with an expansion space 30.
  • FIGURE 7 shows a slightly differing construction of a cold-gas refrigerator.
  • This engine comprises a cylinder 41, in which a com-. pression piston 42 is movable, and a cylinder 43 in which a displacer can move.
  • the compression piston and the displacer are connected through piston rods 44 and 45, respectively, to a driving mechanism (not shown) which can movethe displacer and the compression piston with a given phase difference.
  • the displacer comprises three portions, namely a displacer cap 46, a portion 47 which houses the regenerator, and sealing portion 48. Further. a cooler 49 is housed in the cylinder 43.
  • the working medium can flow from a compression space 50 through the cooler 49, the regenerator 47 and apertures 51 in the displacer through a gap 52 along the displacer cap to an expansion space 53.
  • portion 47 of the displacer has a conical shape so that the gap between this portion and the cylinder downwardly directed becomes wider.
  • a refrigerator of the present construction as realized in practice had the following main dimensions and showed the following conditions in operation:
  • the working medium used was helium.
  • the width of the widening gap was 0.1 mm. at the cold side and 0.25 mm. at the hot side, while the wall of the gap had a purely conical shape.
  • the loss of cold has been found to be much smaller than in a corresponding engine in which the walls of the gap extended in parallel.
  • a device including a cylinder having a piston reciprocating therein to vary the volume of a medium in the working space in said cylinder comprising a seal between said piston and cylinder, and a gap located between said piston and cylinder which communicates at one side with said working space and is bounded at an opposite side'by said seal, said gap being substantially conical inshape with the wider part of said gap being adjacent to said seal.
  • said conical gap at the narrower portion has a width of .1 mm. which increases to .5 mm. at said wider part.
  • a device as claimed in claim 1 wherein. the periph- 5 eral wall of said piston extends in a manner whereby the width of the gap at any point is proportional to a value which is no more than equal to the coefiicient of heat conduction of said medium at the temperature corresponding to this area in operation, and at least equal to the square root of said coefiicient of heat conduction.
  • a device as claimed in claim 1 wherein the narrow portion of said gap has a relative eccentricity of no more than 20%.
  • a device as claimed in claim 1 further providing an annular centering element in the narrow portion of said gap adjacent to said working space, said centering element having apertures regularly divided over its periphery and through which said gap communicates with said working space.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Compressor (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
US415980A 1963-12-24 1964-12-04 Device including at least one cylinder with a piston-shaped body which is movable therein Expired - Lifetime US3292501A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL302577 1963-12-24

Publications (1)

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US3292501A true US3292501A (en) 1966-12-20

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US415980A Expired - Lifetime US3292501A (en) 1963-12-24 1964-12-04 Device including at least one cylinder with a piston-shaped body which is movable therein

Country Status (10)

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US (1) US3292501A (de)
AT (1) AT256149B (de)
BE (1) BE657475A (de)
CH (1) CH441398A (de)
DE (1) DE1228636B (de)
DK (1) DK117432B (de)
ES (1) ES307421A1 (de)
GB (1) GB1081700A (de)
NL (1) NL302577A (de)
SE (1) SE302308B (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3383872A (en) * 1965-12-05 1968-05-21 Philips Corp Device for producing cold with cold loss prevention means
US3650118A (en) * 1969-10-20 1972-03-21 Cryogenic Technology Inc Temperature-staged cryogenic apparatus
US3971230A (en) * 1975-05-05 1976-07-27 Nasa Stirling cycle engine and refrigeration systems
US4726571A (en) * 1986-03-17 1988-02-23 Lear Siegler, Inc. Height control valve with spring return actuator
FR2611031A1 (fr) * 1987-02-16 1988-08-19 Commissariat Energie Atomique Refrigerateur, notamment a cycle de vuilleumier, comportant des pistons suspendus par des paliers a gaz
US5012650A (en) * 1989-10-11 1991-05-07 Apd Cryogenics, Inc. Cryogen thermal storage matrix
US5481879A (en) * 1994-05-31 1996-01-09 Sumitomo Heavy Industries, Ltd. Refrigerator having regenerator
US5590533A (en) * 1994-06-16 1997-01-07 Sumitomo Heavy Industries, Ltd. Refrigerator having regenerator
US6065295A (en) * 1995-12-15 2000-05-23 Leybold Vakuum Gmbh Low-temperature refrigerator with cold head and a process for optimizing said cold head for a desired temperature range
US20050072149A1 (en) * 2001-12-31 2005-04-07 Wilhelm Servis Hot-gas engine

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1012725A (en) * 1908-08-24 1911-12-26 Frederick L Horneffer Motor and compressor.
US1467489A (en) * 1918-08-12 1923-09-11 Bruno V Nordberg Compressor
US1508522A (en) * 1923-11-21 1924-09-16 Automatic Refrigerating Compan Refrigerating machine
US1531709A (en) * 1922-03-30 1925-03-31 Automatic Refrigerating Compan Air-refrigerating machine
US1678957A (en) * 1925-01-29 1928-07-31 Busch Sulzer Bros Diesel Engine Co Piston cooling
US2616242A (en) * 1947-02-15 1952-11-04 Hartford Nat Bank & Trust Co Hot-gas piston engine cylinder and mounting plate assembly
US2836964A (en) * 1953-11-05 1958-06-03 Philips Corp Refrigerating device comprising a gas-refrigerator
US2963871A (en) * 1958-02-28 1960-12-13 Philips Corp Thermo-dynamic reciprocating apparatus
US3188819A (en) * 1963-11-12 1965-06-15 Little Inc A Refrigeration method and apparatus

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1012725A (en) * 1908-08-24 1911-12-26 Frederick L Horneffer Motor and compressor.
US1467489A (en) * 1918-08-12 1923-09-11 Bruno V Nordberg Compressor
US1531709A (en) * 1922-03-30 1925-03-31 Automatic Refrigerating Compan Air-refrigerating machine
US1508522A (en) * 1923-11-21 1924-09-16 Automatic Refrigerating Compan Refrigerating machine
US1678957A (en) * 1925-01-29 1928-07-31 Busch Sulzer Bros Diesel Engine Co Piston cooling
US2616242A (en) * 1947-02-15 1952-11-04 Hartford Nat Bank & Trust Co Hot-gas piston engine cylinder and mounting plate assembly
US2836964A (en) * 1953-11-05 1958-06-03 Philips Corp Refrigerating device comprising a gas-refrigerator
US2963871A (en) * 1958-02-28 1960-12-13 Philips Corp Thermo-dynamic reciprocating apparatus
US3188819A (en) * 1963-11-12 1965-06-15 Little Inc A Refrigeration method and apparatus

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3383872A (en) * 1965-12-05 1968-05-21 Philips Corp Device for producing cold with cold loss prevention means
US3650118A (en) * 1969-10-20 1972-03-21 Cryogenic Technology Inc Temperature-staged cryogenic apparatus
US3971230A (en) * 1975-05-05 1976-07-27 Nasa Stirling cycle engine and refrigeration systems
US4726571A (en) * 1986-03-17 1988-02-23 Lear Siegler, Inc. Height control valve with spring return actuator
FR2611031A1 (fr) * 1987-02-16 1988-08-19 Commissariat Energie Atomique Refrigerateur, notamment a cycle de vuilleumier, comportant des pistons suspendus par des paliers a gaz
EP0279739A1 (de) * 1987-02-16 1988-08-24 Commissariat A L'energie Atomique Kältemaschine, insbesondere mit Vuilleumier-Zyklus, mit durch Gaslager unterstützten Kolben
US4840032A (en) * 1987-02-16 1989-06-20 Commissariat A L'energie Atomique Refrigerator, more particularly with Vuilleumier cycle, comprising pistons suspended by gas bearings
US5012650A (en) * 1989-10-11 1991-05-07 Apd Cryogenics, Inc. Cryogen thermal storage matrix
US5481879A (en) * 1994-05-31 1996-01-09 Sumitomo Heavy Industries, Ltd. Refrigerator having regenerator
US5590533A (en) * 1994-06-16 1997-01-07 Sumitomo Heavy Industries, Ltd. Refrigerator having regenerator
US6065295A (en) * 1995-12-15 2000-05-23 Leybold Vakuum Gmbh Low-temperature refrigerator with cold head and a process for optimizing said cold head for a desired temperature range
US20050072149A1 (en) * 2001-12-31 2005-04-07 Wilhelm Servis Hot-gas engine
US7028473B2 (en) * 2001-12-31 2006-04-18 Wilhelm Servis Hot-gas engine

Also Published As

Publication number Publication date
BE657475A (de)
DK117432B (da) 1970-04-27
AT256149B (de) 1967-08-10
CH441398A (de) 1967-08-15
ES307421A1 (es) 1965-06-01
DE1228636B (de) 1966-11-17
SE302308B (de) 1968-07-15
GB1081700A (en) 1967-08-31
NL302577A (de)

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