US1781073A - Rotary compressor - Google Patents

Description

Patented Nov. "11, `1930 UNITED STATES PATENT oFFIcE HOLGEB NIELSEN, OF BEAVER, FALLS, PENNSYLVANIA, ASSIGNOR TO KEYSTONE BE` FBIGERATING CORPORATION, OF BEAVER FALLS, PENNSYLVANIA, A CORPORATION or rEimsYLvANIA ROTARY COMPRESSOR v application. mea :une 16, 192s. serial no. 286,035.

The invention aims to improve the construction and operation of rotary pumps, to

' centrically in the bore of the pump body and the tips of the blades are made .to touch the inside wall of the pump body while rotating therein'. The as tight contact of the blades within the bo y is accomplished by various.

methods. Some manufacturers split the blade in halves and put springs in between the two half parts so as to continuously keep them out against the inside surface of the pump body. The pump chamber will in this case be a circular cylinder. Other manufacturers 'make the blade in one solid iece and give the bore of the pump bodysuc a shape as to always have a constant distance between the two points where the blade touches, the chamber in such case being a cylinder of noncircular shape, advantageously conforming to the limaon. A preferred form of pump of this nature having packing between the ends of the blade and the chamber wall is described in Roessler Patents Nos. 1,114,046 and 1,649,- 256. Although rotary blade pumps of various types have, as a rule, given satisfaction for pumping liquids, and also for compressing gases to a moderate rate 'of compression, there has always been some lack of satisfaction where a highv compression ratio of gases was desired, because of a tendency for pulsations to be produced in the outlet passage and pump chamber, decreasing the eticiency and smooth operation of the. pump and unnecessarily heatin the gases leaving the pump.

These disa vantages are overcome by the present invention, which may be applied to rotary pumps of various types, as shown in the accompanying drawings, wherein two -preferred forms of compressors for air or gases, having a high ratio between suction and discharge pressure, are shown for purposes of illustration.

In the drawings v Fig. 1 is a lon 'tudinal or axial section through a rotary lade pump of the spring pressed blade type on the section line 1-1 in Fig. 2; the rotor and blade being shown in elevation;

Fig. 2 is atransverse section of the same on the line 2-2 in'Fig. 1; and Y.

Figs. 3 and 4v are views similar to Figs. 1 and 2 of a solid vane orrocker type of rotary pump embodying the invention.

Referring to Figs. 1 and 2 the pump body 11 is provided with an inlet connection 12 and outlet connection 13 ada ted for joining on-to the suction pipe and delivery pi 'e of the fluid pressure system. The pump dy contains a chamber which may be cylindrical and which contains eccentricall for rotation therein a cylindrical rum or rotor 14 provided with a transverse slot for the blades 15 which are'slidable therein and are normally kept pressed in close contact against the inner wall of the vpump chamber by springs 16. The rotor is mounted lin suitable bearings, and contacts with the side of the chamber between the inlet port 17 and outlet ort 18 to form a gas tight joint therewith.

t also contains grooves or recesses 19 adjacent to the pressure side of the vanes at the outlet end of the pump chamber ad-a ted to register with the out-let port 18 perio ically.

An oil port 2O is provided in the end Wall of the pump chamber in position to be uncovered by the recesses 19 at about the beginning of each compression period. The oil port is in communication with a suitable source of oil under suicient pressure to permit a jet of oil to be shot into the pump chamber` in advance of each blade for each rotationof the pump.

The pump chamber is provided with a port or passage 21 positioned near the outlet port 18 and furnished with a valve 22, normally held closed by springs'or other suitable means, for relieving excessive ressurev produced by liquid particles trapped in -=the pump chamber or otherwise. This lvalve may discharge into any suitable outlet, such as the outlet passage 13 as shown.

The pump may be driven in the direction mounted v of the arrow in Fig. 2 by a motor mounted on the rotor shaft, orby gearing from any suitable source of power.l For small compresser units, the rotor is preferably driven at a speed of from fifteen to eighteen hundred revolutions per minute, but the speed lwill be controlled by the circumstances of use.

s pressed in front of the following blade in the diminishing space as the'blade approaches the outlet port18 until vthe'adjacent recess 19 uncovers the outlet port.

The size and relative location ofthe inlet and outlet ports, dimensions ofthe chamber and-rotor, and size of the recesses 19 in the rotor, are chosen to suit the desired compression ratio 'and capacit of the pump at the speed of rotation for which it is designed.

With the sizes and relative positions of the parts as illustrated, '.the blade will move through anl angle of about 180, compressing the gas gradually to a pressure corresponding approximately to that in the outlet passage, before the recess 19 uncoversthe outlet port 18, and permits discharge of the compressed gas ffrom thev pump chamber. This pressure in the illustrative example may be about. 50 to 60 lbs. per sq. in. correspondingto a compression ratio of 4 or 5 to one. There is no tendency for pulsations to be produced in the outlet passage, because there can be'no flow back into the` pump chamber when the outlet port is uncovered as would be the case with the means for closing the outlet passage until the proper compression pressure is attained in theppump chamber.

In the form of pump illustrated in Figs. 3 and 4, the casing 23, rotor 24 and inlet and outlet ports 25, 26, oil port 27, relief valve 28 and driving means are similar to the form illustrated in Figs. 1 and 2, but the rotor has a solid blade 29 provided with rockers 30 at its ends bearing against the inside wall of the pump chamber, which is bored to conform to a cylinder of limaon shape. The recesses 31 in'the'rotor function as described above to uncover the outlet port 26 at the proper times to permit a smooth discharge, and prevent rush of gas back into the chamber from the outlet passages atall other times.

It is evident that the size and location ofv the outlet port may be varied to correspond to different compression ratios, and that the compression ratiomay'be changed by shifting the position of the outlet ort angularly with respect to the inlet port. his may readily be accomplished by moving the end plate etween the two blades, and.`

angularly upon the pump body, or by other convenient means. In practice, different ro-` tors and end plates may be furnished to suit various compression ratios and conditions of use. Care should be taken, however, that the cut-'off edge ofthe outlet port 18 (just yisible through the groove 19 in Fig. 2) is spaced from the line of contact of the rotor 14 with the chamber wall `11 by such an'amount that the port 18 will be entirely closed before the leading edge of the groove 19 passes the line of contact and establishes communication with the low pressure side ofthe pump, in order that there may be no flow of compressed fluid past the line of contact by way of the groove from the discharge port to the low side .of the pump. l A

The invention is not restricted to the types of pumps shown in the drawings, nor to the details of construction illustrated therein,.as obviously it maybe applied to divers forms of rotary pumps.

I claim: 1. A rotary compressor having'a chamber provided with inlet and outlet ports spaced angularly 'withrespectl to each other and communicating, respectively, with inlet and outlet passages, a rotor eccentrically mounted within said chamber and contacting with its side wall between said inlet and outlet ports to prevent passage of fluid therebetween, said rotor having blade means adapted to contact' with the side Walls of the chamber throughout the compression period subdividingthe .same into a plurality of compression. chambers, said rotor comprising a closure for said outlet port, said rotoi` being provided with, grooves adjacent the forward side ,of the blade means sequentially establishing com .municationfrom the surface of said rotor. ordinary types of rotary pumps having no.-

to the outletl port as said rotor is revolved, saidputlet port being so located in said chamberyfwall that communication thereto from the respective compression chambers will be prevented by said rotor while the pressure within each compression chamber isy being built upto substantially the ressurein the discharge passage and will e sequentially establishedv from each chamber by the groove communication therefrom when the pressure in" such chamber substantially equals the pressure in the discharge passage, whereby oscillating flow of compressed fluid through said outlet port will be substantially prevented.

-2.' A- rotary compressor having a chamber provided with inlet and outlet ports spaced angularly with respect to each other and communicating, respectively, with inlet and outlet passages, a rotor eccentrically mounted Within said chamber and contacting with its side wal-1 between said inlet and outlet ports to prevent passage of Huid therebetween, said aoy rotor having blade means adapted to cony in the discharge throughout the. compression period subdividing the same into a plurality of compression chambers will' be prevented by said rotor whlle the pressure within such compressionchambers is being built upto substantially the particular pressure in the discharge passage and will be sequentially established from each chamber by the groove communicating therefrom when the pressure in such chamber substantially equals the pressurein the discharge passage, whereby oscillating flow of compressed fluid through said outlet port will be substantially prevented.

v 3. A rotary compressor having a chamber provided witlr inlet and outlet passages and ports spaced yangularly with respect to each other, theoutlet port being disposed in an end wall of said chamber, a rotor eccentrically mounted within said chamber to close said outlet port and contacting with its side wall between' said inlet and outlet ports to prevent assage of fluid therebetween, said rotor having blade means adapted to contact with the side wall of the chamber throughout the compression period, said rotor closing said outlet port while the pressure within the chamber is being built up to substantially the pressure in the discharge passage, to'preventback flow of fluidinto said chamber from the discharge passage, said rotor' being provided with a groove positioned to uncover said outet port when the pressure within the chamber reaches substantially the pressure passage, for discharging the compressed fluid.

4. A rotary compressor having a chamber provided with inlet and outletvpassages and ports spaced angularly with respect` to each other, the outlet port being disposed in an end Wall of said chamber, a rotor eccentrically mounted within said chamber to close said outlet port and contacting with its side wall between said inlet and outlet ports to prevent passage of fluid therebetween, said rotor having blade means adapted to contact with the side ywall of the chamber throughout the compression period, said -rotor closing said outlet port While the pressure in the compression chamber is being built up to substantially the pressure in the discharge passage, to preventV backv flow of fluid into said compression chamber from the discharge passagensaid rotor being provided with a groove POSltlOned to uncover said outlet port when the vpressure reaches substantially the pressure in the discharge passage for discharging the compressed fluid, the portion of said end wall carrying said 'outlet ort being capable of being moved to provi e for the shifting of the port to cause'earlier or later opening to substantially correspond to lesser or greater ratios of compression atwhich the lcompressor may be worked.

5. A rotary compressor having a chamber provided with inlet and outlet ports spaced angularly with respect to each other, a rotor eccentrically mounted Within said chamber and comprising blade means adapted to contact With the side Wall v of the chamber throughout `the compression period, said chamber being provided with a port for the supply of lubricant under pressure, and means for covering said'lubricant port during the greater part of thesuction and compression cycle to prevent excessive supply and uneven distribution of lubricant to said chamber, said means providing for uncovering said lubricant port during only a small interval of time when the pressure is substantially reduced in saidchamber topermit injection of a small quantity of lubricant under considerable pressure.

6. A rotary compressor having a chamber provided with inlet and outlet ports spaced angularly with respect to each other, a rotor eccentrically mounted within said chamber andA comprising blade means adapted to contact with the side wall of the chamber throughout the compression period, said chamber being provided with a port for the supply of lubricant under pressure, and means carried by said rotor for covering said lubricant port during the greater part of the suction and compression cycle to prevent excessive supply and uneven distribution of lubricant tosaid chamber, said means providing for uncovering said 4lubricant port vduring only a small interval of time when the pressure is substantially reduced in said chamber to permit injection of a small quantity of lubricant under considerable pressure.

7. A rotary compressorhaving a chamber provided with inlet and outlet ports spaced angularly with respect -to each other, a rotor eccentrically mounted within said chamber and comprising blademeans adapted to contact with the sid all of the chamber throughout the c 'pression period, said chamber being provided with a port'for the supply of lubricant under pressure, and means carried by said rotor for covering said lubricant port during the greater part of the suction and compression cycle to prevent excessive supply and uneven distribution of lubricant to said chamber, said means providing for uncovering said lubricant port during only a small interval of time when the pressure is substantiall reduced in said chamber to permit injection of a small quantity of lubricant under considerable pressure, said port and last named means being positionedjso that the port, when uncovered, will f discharge directly in front of the blade s means. u 8. A rotary compressor having a chamber provided with inlet and outlet ports spaced angularly with res ect to each other, said chamber being furt er provided with a port m for supplying lubricant under pressure, a ro'- tor eccentrically Ymounted within said chamber and comprising blade means ada ted to contact with the sidewall of the c amber throughout the compression period, said .ro

l tor being arranged to prevent passage of fluid between said inlet and outletl orts except as it is compressegdand delivere by rotation of the same','and means arranged to closev said lubricant port during the greaterpart 3 of the suction-and compression cycle and open the same during only a small interval of time when the ressure is substantially reduced in4 said chamber and to close said discharge port while the fluid is being com ressed to substantiallythe pressure of discliarge and open the sameonly when the fluid has been compressed to substantially the pressure of discharge, substantially as and for the purpose described.

provided with inlet'and outlet ports spaced angularly with respect-to each other, said chamber being further provided with a port for supplying lubricant under presu're, a ro- 7;; tor eccentricall ber and comprlsing blade means ada ted to contact with the sidewall of the c amber throughout the compression period, said rotor fluid between said inlet and outlet orts except as it is compressed and delivered) by rotation of the same,.and means carried by said rotor and arranged to cover said lubricant port duringthe greater part of the lsuction and compression cycle and uncover the same during only a small interval of time when the pressure is substantially reduced in said chamber and to cover said discharge port while the fluid is being compressed to substantially the pressure of discharge and uncover the same only when the Huid has been vcom ressed to substantially the pressure of disc arge,v substantially as and for the purposes described. K

10. A rotary compressor having a chamber vprovided with linlet and outlet ports spaced angu1arly.wit h res ect to leach/other; said chamber being urt er provided with a port fior-"supplying lubricant under pressure; a roce toreccentrically mounted within said chamyand comprising blade means ada ted to act with the side wall of the ciamber agitent the compression period said rog arranged to prevent passage of fluid n said inlet an outlet ports except as 'claim 9 further characterized in that the por- 9. A rotary compressor having a chamber mounted within said chameing arranged to prevent passage ofl it is compressed and' delivered by rotation of the same; and means carried by said rotor arranged to cover said lubricant port during the greater part of the suction and compression cycle and uncover the same during only a small 'interval of time when the partsv are in such position that the port will discharge directly in front of said blade means and when the pressure is substantially reduced in said chamber, to inject a well distributed limited supply of lubricant directly in front of the blade means, and to cover said discharge port while the iluid'is being compressed to substantially the pressure of dis-\ charge and to uncover the same only when go the fiuid has been compressed to substantially thefpressure of discharge; substantially as and for the 'purposes described.

11. The rotary compressor as set forth in tion of said compressor carrying said'o-utlet port is capable of being moved to provide for the shifting of the port to cause earlier y or later uncoveringof the same to substantially correspondto lesser or greater ratios of compression at which the compressor maybe worked. l l

12. Av rotary compressor comprising a body. with a cylindrical bore, a circular cylindrical rotor eccentrically mounted for ro tation therein, a transverse Aslot extending axially through said rotor, movable means mounted in said slot adapted to contact with said bore at its ends to rovide a fluid tight joint, discharge and intalie ports in said body, means carried ly'said rotor for coveringv said discharge port rin-g a portion of the period of rotation beforethe iuid has been raised to substantially the pressure of discharge,a port for supplying lubricant under pressure to said bore, and means carried bysaid rotor forycovering saidvlubricant port except dura small portion of the compression cycle w en the pressure in the space adjacent the lubricating port is substantially less than the -oil pressure, whereby the oil is injected in r'the form of a jet'.

'" 13. A rotary compressor comprising I a body,- a rotor eccentrically mounted for rotation therein, dischargel and intake ports in Isaid body, a port for supplying lubricant under pressure to said compressor body, and means carried by said rotor for covering said oil port during a portion of the perio ed within said chamber to close said outlet port and contacting with its side wall between said inlet and outlet ports to prevent passage of iuid therebetween, said rotor having blade means adapted to Contact with the side Wall of the chamber throughout the compression period, said rotor closing said outlet port while the pressure within the chamber is being built up to substantially the pressure in the discharge passage, to prevent back flow of uid into said chamber from the discharge passage, said rotor being provided with a groove positioned to uncover said outlet port when the pressure within the chamber reaches substantially the pressure in the discharge passage, for discharging the compressed fluid.

15. A rotary compressor having a rotor having line Contact with the side wall of its compression chamber, an outlet port in its end -wall normally closed by the rotor, and a groove in the rotor for opening communication between the outlet port and the compression chamber, said outlet port being positioned with its cut-oit edge so spaced from the line of contact that the port will be entirely closed before the leading portion of the groove passes beyond said line of Contact.

In testimony whereof, I have signed my name to this specification.

HOLGER NELSEN.

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