US2068918A - Rotary piston machine - Google Patents

Rotary piston machine Download PDF

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US2068918A
US2068918A US699366A US69936633A US2068918A US 2068918 A US2068918 A US 2068918A US 699366 A US699366 A US 699366A US 69936633 A US69936633 A US 69936633A US 2068918 A US2068918 A US 2068918A
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blades
rotary piston
rotor
casing
distance
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US699366A
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Kagi Emil
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Sulzer AG
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Sulzer AG
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/30—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
    • F04C2/34—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members
    • F04C2/344—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
    • F04C2/3441—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member the inner and outer member being in contact along one line or continuous surface substantially parallel to the axis of rotation
    • F04C2/3442—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member the inner and outer member being in contact along one line or continuous surface substantially parallel to the axis of rotation the surfaces of the inner and outer member, forming the working space, being surfaces of revolution
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C21/00—Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00
    • F01C21/08—Rotary pistons
    • F01C21/0809—Construction of vanes or vane holders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/30—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
    • F04C18/34—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members
    • F04C18/344—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/06—Silencing

Definitions

  • This invention relates to rotary piston machines such, for example, as rotary pumps or compressors and of the kind comprising a rotary piston eccentrically arranged within a casing and carry- 5 ing a series of blades circumferentially spaced apart on the rotor; so as to bear against .the interior of the casing.
  • the circumferential distances between adjacent blades are not all equal. In this way the successive disturbances due to the blades do not take place at regular intervals so that a high pitched penetrating note is not produced, the vibrations producing a low pitch note situated within a sound range scarcely perceptible by the ear.
  • the invention is particularly advantageous as applied to rotary compressors wherein each cell formed between two adjacent blades is closed during compression of the working medium and is opened when the leading blade of the pair passes over the delivery conduit or port.
  • the pressure in each cell when opening commences in this manner, never agrees exactly with the pressure in the delivery conduit.
  • the cells open'into the delivery conduit in succession and at regular intervals. the successive flow oscillations produce a high pitched penetrating note.
  • the sequence of the oscillations is renderedirregular and the production of a penetrating note thereby avoided.
  • the medium to be delivered enters through an inlet conduit l, the blades 2 carried by the eccentric 25 rotor or drum 3 forming cells 4 in which the medium is compressed and finally delivered through a delivery conduit 5.
  • Each blade 2 can slide in a slot 6 in the drum 3 so that as the drum rotates the blades are held by centrifugal force 30 in engagement with the interior of the casing I, the drum rotating in the direction of the arrow 5.
  • the blades 2 are irregularly spaced apart, the distance between adjacent blades uniformlydecreasing 35 from a maximum at the region a to a minimum at the region I; and then again increasing uniformly to the maximum value at the region a.
  • the distance between adjacent blades decreases and 40 increases twice.
  • the distance between adjacent blades decreases uniformly from a. maximumat the region a to a minimum at the region I), then increases uniformly to the maximum value at the second region a'whereupon it again 45 decreases uniformly to the minimum value at the second region I), after which the distance again increases to the maximum value.
  • the uniform increase and decrease of the distance between ad- 50 jacent blades takes place three times, i. e. a uniform decrease over each are between the regions a. to b and a uniform increase over each are between the regions b to a. It will be understood that if desired, and particularly for machines having drums of large diameter and a large number of blades, the increase and decrease of the distance between adjacent blades may be repeated still more often.
  • Figure 6 illustrates a construction in which the distance between adjacent blades varies irregularly.
  • the individual vibrations will be dominated by a periodical main vibration having a periodicity corresponding to one revolution of the drum and which will be perceived by the car as a fundamental note
  • the remaining individual vibrations of small magnitude and superposed on the fundamental will distort the pure fundamental, so as to produce a sound in which the deep note will at all times predominate.
  • the pitch of the note will be lower by four octaves than that of a sixteen blade rotor in which the distances between adjacent blades are equal, since the time of vibration is sixteen times as long and the frequency sixteen times less.
  • the sounds caused by compressors of the size under consideration may be resolved in certain circumstances into harmonic components in order blade and a radius of the rotor at the point where the .blade meets the rotor may differ from the corresponding angle of one or more of the other blades.
  • the invention may be applied to any rotary piston machines such, for example, as rotary 'pumps, compressors or fans. Further, though the invention has been described as applied to a machine in which the blades can slide in slots formed in a drum, the invention is also applicable to other constructions such, for example, as those in which blades of the drag type are pivotally. connected to the eccentric or rotor, so that the outer end of each blade is held in engagement with the inner surface of the casing by centrifugal force acting on the blade.
  • a rotary piston machine comprising a casing having an inlet and an outlet, a rotary piston eccentrically arranged within the casing, blades carried by said rotary'piston, said blades being circumferentially spaced apart and movable inwardly and outwardly of said piston as it rotates, the circumferential distances between adjacent blades being not all equal, the angle between any blade and a radius of the rotor at the point thereon where the blade meets the circumference of the rotor diifering fromthe corresponding angle of at least one other blade.
  • a rotary piston machine comprising a casing having an inlet and an outlet, a rotary piston eccentrically arranged within the casing, blades carried by said rotary piston, said blades being circumferentially spaced apart and movable inwardly and outwardly of said piston as it rotates, the circumferential distances between adjacent blades being not all equal, the spacing of the blades taken in succession around the circumference of the rotor in the direction of rotation gradually decreasing from a maximum value to a minimum value and then gradually increasing to the maximum value.

Description

Jan. 26, 1937. E. K GI 2,068,918
ROTARY PISTON MACHINE Filed Nov. 25, 1953 Patented Jan. '26, 1937 PATENT OFFICE 2,068,918 ROTARY PISTON MACHINE Emil Kagi, Winterthur, Switzerland, assignor to the firm Sulzer Freres Socit Anonyme, Winterthur, Switzerland Application November 23, 1933, Serial No. 699,366- In Switzerland July 7, 1933 3 Claims.
This invention relates to rotary piston machines such, for example, as rotary pumps or compressors and of the kind comprising a rotary piston eccentrically arranged within a casing and carry- 5 ing a series of blades circumferentially spaced apart on the rotor; so as to bear against .the interior of the casing.
Pumps and compressors of this type are liable to be noisy since a large number of blades are usually provided spaced apart at equal intervals around the circumference of the piston so that the blades, passing in rapid succession and at equal intervals over the inlet and outlet ports in the casing, produce a high pitched penetrating note. The casing of the machine, as also other parts, has a natural period of vibration the frequency of which is often of substantially the same order as that of the note produced by the rotor. When therefore the vibrations of the casing and those due to the rotor bladescome into resonance the note due to the rotor is intensifled.
In a rotary piston machine according to the present invention the circumferential distances between adjacent blades are not all equal. In this way the successive disturbances due to the blades do not take place at regular intervals so that a high pitched penetrating note is not produced, the vibrations producing a low pitch note situated within a sound range scarcely perceptible by the ear.
The invention is particularly advantageous as applied to rotary compressors wherein each cell formed between two adjacent blades is closed during compression of the working medium and is opened when the leading blade of the pair passes over the delivery conduit or port. The pressure in each cell, when opening commences in this manner, never agrees exactly with the pressure in the delivery conduit. Thus, when communication between a cell and the delivery conduit commences either the contents of the cell expand into the delivery conduit or medium within the delivery conduit tends to expand into the cell. As therefore the cells open'into the delivery conduit in succession and at regular intervals. the successive flow oscillations produce a high pitched penetrating note. Similarly, if the cells have not completely emptied into the delivery conduit so that compressed medium is carried round in each cell from the delivery side to the suction side this medium will expand into the suction conduit and thus cause oscillations of flow due to this backflow, such oscillations taking place at 65 regular intervals. In accordance with the present invention the sequence of the oscillations is renderedirregular and the production of a penetrating note thereby avoided.
Experimentshave shown that the reduction of noise is particularly pronounced when the maxi- 5 mum or minimum distance between adjacent blades differs from the mean distance by more than .05 times such mean distance.
distance between adjacent blades differ from the 20 mean suchdistance by more than .05 times the said mean distance.
In all the constructions illustrated the medium to be delivered enters through an inlet conduit l, the blades 2 carried by the eccentric 25 rotor or drum 3 forming cells 4 in which the medium is compressed and finally delivered through a delivery conduit 5. Each blade 2 can slide in a slot 6 in the drum 3 so that as the drum rotates the blades are held by centrifugal force 30 in engagement with the interior of the casing I, the drum rotating in the direction of the arrow 5.
In the construction shown in Figure 1 the blades 2 are irregularly spaced apart, the distance between adjacent blades uniformlydecreasing 35 from a maximum at the region a to a minimum at the region I; and then again increasing uniformly to the maximum value at the region a.
In the construction illustrated in Figure 2 the distance between adjacent blades decreases and 40 increases twice. Thus, the distance between adjacent blades decreases uniformly from a. maximumat the region a to a minimum at the region I), then increases uniformly to the maximum value at the second region a'whereupon it again 45 decreases uniformly to the minimum value at the second region I), after which the distance again increases to the maximum value. In the construction shown in Figure 3 the uniform increase and decrease of the distance between ad- 50 jacent blades takes place three times, i. e. a uniform decrease over each are between the regions a. to b and a uniform increase over each are between the regions b to a. It will be understood that if desired, and particularly for machines having drums of large diameter and a large number of blades, the increase and decrease of the distance between adjacent blades may be repeated still more often.
In the construction illustrated in Figure 4 the distance between adjacent blades decreases suddenly from a maximum at the region a to a minimum at the region b whereupon the distance gradually increases to the maximum at the region a. If desired this sudden decrease and gradual increase may be repeated several times as shown in Figure 5 in which the distance between adjacent blades suddenly decreases from a maximum to a minimum value over each arc a to b and increases gradually from the minimum to the maximum value over each arc b to a.
Figure 6 illustrates a construction in which the distance between adjacent blades varies irregularly.
If the blades were regularly spaced apart, that is to say so that all the distances between the several pairs of adjacent blades were equal, each blade in passing over the inlet and delivery conduits I and 5 would cause a blow-like impact so that a series of these impacts occur at regular intervals thereby producing a periodical vibration corresponding to a uniform high pitched whistling note. When, however, the blades are spaced at unequal intervals round the drum the impacts will take place at varying intervals so that, provided the spacings of the blades have been suitably chosen, the individually produced vibrations will disappear at certain points during each revolution of the drum owing to interference and will only tend to be superposed at relatively wide intervals. The individual vibrations will be dominated by a periodical main vibration having a periodicity corresponding to one revolution of the drum and which will be perceived by the car as a fundamental note The remaining individual vibrations of small magnitude and superposed on the fundamental will distort the pure fundamental, so as to produce a sound in which the deep note will at all times predominate. In the case, for example, of a sixteen blade rotor embodying the invention the pitch of the note will be lower by four octaves than that of a sixteen blade rotor in which the distances between adjacent blades are equal, since the time of vibration is sixteen times as long and the frequency sixteen times less.
Since the human ear perceives only sounds within a. given range of vibration, high notes such as those produced by rotary pistons having regularly spaced bladesare perceived as a penetrating whistling note whilst deeper notes are perceived scarely or not at all. When the blades are irregularly spaced the time of vibration is considerably lengthened and the tone thus lowered so that the efl'ect on the human ear is reduced. Further, deep notes are less liable to come into resonance with parts of the machine and thus are unlikely to penetrate. the casing walls since these-are unable to vibrate at such small frequency. The casing itself thus acts, in effect, as a vibration damper.
In calculating the spacing of the blades the sounds caused by compressors of the size under consideration may be resolved in certain circumstances into harmonic components in order blade and a radius of the rotor at the point where the .blade meets the rotor may differ from the corresponding angle of one or more of the other blades.
The invention may be applied to any rotary piston machines such, for example, as rotary 'pumps, compressors or fans. Further, though the invention has been described as applied to a machine in which the blades can slide in slots formed in a drum, the invention is also applicable to other constructions such, for example, as those in which blades of the drag type are pivotally. connected to the eccentric or rotor, so that the outer end of each blade is held in engagement with the inner surface of the casing by centrifugal force acting on the blade.
I claim:
1. A rotary piston machine comprising a casing having an inlet and an outlet, a rotary piston eccentrically arranged within the casing, blades carried by said rotary'piston, said blades being circumferentially spaced apart and movable inwardly and outwardly of said piston as it rotates, the circumferential distances between adjacent blades being not all equal, the angle between any blade and a radius of the rotor at the point thereon where the blade meets the circumference of the rotor diifering fromthe corresponding angle of at least one other blade.
2. A rotary piston machine comprising a casing having an inlet and an outlet, a rotary piston eccentrically arranged within the casing, blades carried by said rotary piston, said blades being circumferentially spaced apart and movable inwardly and outwardly of said piston as it rotates, the circumferential distances between adjacent blades being not all equal, the spacing of the blades taken in succession around the circumference of the rotor in the direction of rotation gradually decreasing from a maximum value to a minimum value and then gradually increasing to the maximum value.
3. A rotary piston machine comprising a casing having an inlet and an outlet, a rotary piston eccentrically arranged within the casing, blades carried by said rotary piston, said blades being circumferentially spaced apart and movable inwardly and outwardly of said piston as it rotates, the circumferential distances between adjacent blades being not all equal, the spacing of the blades taken in succession around the circumference of the rotor in the direction of rotation gradually decreasing from a maximum value to a minimum value and then gradually increasing to the maximum value, and the gradual decrease and increase of the spacing taking place at least twice over the circumference of the rotor.
EMIL KKGI.
US699366A 1933-07-07 1933-11-23 Rotary piston machine Expired - Lifetime US2068918A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2466230A (en) * 1946-02-09 1949-04-05 Stromberg Carlson Co Pulse time modulation system
US2562698A (en) * 1945-12-03 1951-07-31 Leonard F Clerc Rotary compressor
US2839007A (en) * 1952-04-16 1958-06-17 Melba L Benedek Rotary fluid pressure device
US6497557B2 (en) * 2000-12-27 2002-12-24 Delphi Technologies, Inc. Sliding vane pump
US20030124014A1 (en) * 2001-11-30 2003-07-03 Hidehisa Takatsu Gas compressor

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2562698A (en) * 1945-12-03 1951-07-31 Leonard F Clerc Rotary compressor
US2466230A (en) * 1946-02-09 1949-04-05 Stromberg Carlson Co Pulse time modulation system
US2839007A (en) * 1952-04-16 1958-06-17 Melba L Benedek Rotary fluid pressure device
US6497557B2 (en) * 2000-12-27 2002-12-24 Delphi Technologies, Inc. Sliding vane pump
US20030124014A1 (en) * 2001-11-30 2003-07-03 Hidehisa Takatsu Gas compressor
US6824370B2 (en) * 2001-11-30 2004-11-30 Calsonic Compressors Manufacturing Inc. Rotary vane gas compressor having unequal intervals between vane grooves and/or unequal distances between vane grooves and rotor center

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