US2522824A - Rotary compressor - Google Patents

Description

Sept. 19, 1950 T. L. HICKS 2,522,824

ROTARY COMPRESSOR Filed Aug. 29, 1944 2 Sheets-Shet 1 1 Sept. 19, 1950 T. L. mcks 2 2 ROTARY COMPRESSOR Filed Aug. 29, 1944 2 Sheets-Sheet 2 Ill/1% @W III ll] 76 nn min Fig-l2 five/2123;

7750/71 as Z Patented Sept. 19, 1950 UNITED STATES PATENT OFFICE.

ROTARY COMPRESSOR Thomas L. Hicks, Toronto, Ontario, Canada Application August 29, 1844, Serial No. 551,883 7 Claims. (Cl. 230-149) The invention relates to improvements in rotary compressors as described in the present specification and shown in the accompanying drawings that form a part of the same.

While it has been recognised that the rotary compressor has definite advantages over compressors of other types, particularly where relatively slow speed is desirable as in the operation of motor vehicles, refrigerators and other devices, the full scope of such advantages has not been attainable to date due principally to the fact that no efllcient means has up to the present been known for effectually preventing the escape of air, gas or other liquid from the high compression side to the low compression side.

Due to this lack of a positive seal heretofore it has not been possible to construct compressors of this type of light metals, or of plastics, due to the fact that the barrel being of greater diameter than the rotor would expand to a greater extent than the rotor and thus create a clearthe individual blades as they pass the sealing point.

A still further object of the invention is to provide means for automatically controlling the flow or oil from one blade slot to the other to compensate for the changing positions of the blades in the rotation of the rotor.

And generally the objects of the invention are to provide an eilicient rotary compressor 0! durable construction, having a minimum of moving parts, which will require little or no attention.

In describing the invention reference will be ance therebetween for the escape of the gas. In

addition no eflicient means has hitherto been provided for insuring a positive supply of oil at all times nor for automatically varying the pressure of oil in proportion to the load.

The main objectof the present invention isv to provide a levered seal between the rotor and barrel which will be automatically varied by the varying pressures of oil to effectually seal the high compression side from the low compression side.

Another object of the invention is to provide a seal of a material more readily effected by changes in temperature that the material of which the rotor and barrel are constructed whereby to compensate for the difference in the degree of expansion between said rotor and barrel which are of different dimensions and therefore do not respond similarly to changes in temperature.

A further object is to provide a rotary compressor which can be constructed of light metal, or of plastics, and which will prove equally efficient between extremely low and very high speeds.

A still further object of the invention is to provide a positive oil supply automatically variable in accordance with the speed of the rotor and which will operate to exert peripheral and lateral pressure against the blades to hold same in contact with the inner periphery and the end walls of the barrel.

A further object of the invention is to provide means for increasing the outward pressure on made to the accompanying drawings. in which:

Figure 1 is a central transverse sectional view through my improved compressor.

Figure 2 is a longitudinal sectional view taken on the line 2-2 of Figure l.

Figure 3 is a face view of one of the blades.

Figure 4 is an edge view of the blade shown in Figure 3.

lFigure 5 is a face view of a modified form of b ade.

Figure 6 is an edge view of the blade shown in Figure 5.

Figure 7 is a face view of another form of blade.

Figure 8 is an edge view of the blade shown in Figure 7.

Figure 9 is a central transverse sectional view through a compressor embodying an alternative method of supplying oil to the blades.

Figure 10 is a sectional view taken onv the line l0iI0 of Figure 9.

Figure 11 is a cross sectional view taken on the line il'll of Figure 10.

Figure 12 is a longitudinal sectional view through the top portion of a compressor embodying a modification of the oilpressure feed to the sealing member.

Like numerals of reference indicate corresponding parts in the various figures.

Referring to the drawings the numeral l indicates the casing which constitutes the compression chamber, which casing is open at both ends and is mounted on a suitable base 2 and is provided with a suitable inlet 3.

The casing l is closed at its ends by heads 4 and respectively and said heads are provided with opposed eccentrically disposed hubs 6 and 1 respectively which maybe bolted or otherwise secured to the casing and which provide bearings for the driven rotor shaft 8. The hub I is closed at its end as at 9. A suitable packing member In may be inserted in the hub 6.

H is the rotor which is eccentrically arranged within the casing I so as to contact the inner face of the casing at one point and therefore provide a low compression side and a high compression side, said rotor being keyed to-the shaft 8. as at l2. The rotor is provided with a number of equi-spaced radial slots l3 in which are located the slidable blades l4, the said slotsextending into the rotor from the outer surface and terminating equi-distant from the inner wall.

The head 5 is provided with an inner circular groove I5 registering with the inner ends of the slots I3 whereby to provide a circulatory system whereby the supply of oil behind the blades will be varied in accordance with the positions of said baldes and will besufficient to hold said blades in contact with the inner face of the casing, as will be explained in detail hereinafter.

The head 4 is provided with an inner circular groove l5a so positioned as to register with the 4 blades with the walls of the casing will increase and decrease proportionately with the load.

In Figures 3 and 4 one type of blade is shown comprising two endwise related sections 28 and 30 and a. central section 3! all intcrlockingly engaged, the end sections being recessed. as at 32, and being cut, diagonally. as at 33. to provide, when assembled, a substantially V-shaped shoulder and the central section having a tongue 34 extending into the recesses in said sections, and a centrally disposed raised portion 35 at each side of inverted V shape adapted to bear against the shoulders of the V formed by the end sections whereby pressure against the inner end of the central section will cause the end sections to be spread apart into close engagement with the end walls of the compression chamber. A boss 36 extending outwardly from the inner end of each of the blades provides means for keeping the blades spaced from the inner ends of the blade slots whereby to provide at all times an oil space at the inner end of each blade. Grooves 36a in the blades permit oil to pass between the blades and the walls of the casing whereby to respective blade slots i3 and to overlap the wall of the rotor beyond the inner ends of said slots whereby to provide an oil seal to prevent the escape of oil to the shaft-housing 5 and thus make unnecessary the use, of packing rings.

A combined oil reservoir and separating chamber I! is provided at one end of the compressor between the head 5 and a plate or wall I 8 spaced from saidhead and having an inwardly extending annular wall I9 bolted or otherwise secured to the said head. The chamber I1 is provided with an oil feed inlet and is further provided with an outlet 2| located near the top of the wall l8 and said inlet is provided with a screw closure 22.

The air or other liquid being compressed is released from the high compression side of the casing I into the separator chamber l'l through an outlet port 24 in the head 5.

An' oil pipe 25 leads from the oil reservoir through a suitable opening 25 in the head 5 located just below the oil groove IS in the inner face of said head and at a point opposite to the upper unoccupied portion of each blade slot as the latter is brought to its lowermost vertical position, whereby oil may be fed to the interior of each blade slot in succession in the rotation of the rotor. As the oil opening 26 and the groove I5 both communicate with the blade slots as the latter reach their vertical lower positions the oil received from the oil pipe 25 will pass into the said groove for delivery to the other blade slots at all times and thus will be formed .an oil cir-v culating system common to all of the blade slots with the amount of oil in each slot automatically regulated accordingto the positions of the blades.

A valve 21 located in the pipe 25 and seating against a shoulder 28 prevents the oil from running back into the reservoir. I

The blades are preferably formed of a number of sections whereby pressure of oil against the inner ends will cause the blades to spread laterally into close engagement with the inner faces of the heads 4 and 5 and whereby the spreading influence will be automatically regulated by the pressure of the oil according to the speed at which the rotor is turning, 50 that contact of the the other end, which is located at the low compression side being substantially at right angles to the interior face of the casing.

40 is a sealing lever shaped correspondingly to the shape of the recess 38 and having its inner face shaped to follow the contour of the inner wall of the compression chamber, the said lever being fulcrumed in the semi-circular end of said recess and being adapted when inward pressure is brought to bear on the other, or reduced, end

which is located at the low compression side to cause contact with the wall of the rotor and with low compression side is preferably somewhat.

longer than the portion at the high compression side whereby to provide adequate leverage to insure the required pressure against the rotor and blades.

The portion of the wall of the casing directly above the free end of the sealing lever 40 is cut away to provide a recess 4| extending the full width of said lever and in this recess and lying on the lever and movable therewith is a strip 42 of metal or other suitable material, such strip 42 being of lesser depth than the recess 4| whereby to leave an oil chamber thereabove, and being of slightly lesser width than said recess to permit of the passage of oil to the low pressure side of the compression chamber.

An oil pipe 43 leading from the interior of the oil reservoir and extending through the head 5 into communication with the recess 4| provides means for supplying apressure of oil against the free end of the sealing lever 40 to cause the latter to bear inwardly against the rotor blades. It is apparent that pressure on the lever will vary in accordance with the discharge pressure.

The operation of the device described hereinabove is as follows: The air, gas, or other liquid is fed into the low compression side of the casing I through the inlet and is carried around and compressed by the blades 14 and is emitted through the outlet 24 into the chamber I1 from ment with the openings 53, 84, 65 and 85 whereby which it is expelled through the outlet 2| as required. During the rotation of the rotor 8 the oil is carried upwardly from the oil reservoir through the pipe 25 and as each blade reaches its lowest position a supply of oil is permitted to enter the space between the said blade and the inner end of the blade slot from which it flows into the groove I! in the head 5 of the casing and thence into the other blade slots whereby to exert outward pressure on the blades. This groove acts in cooperation with the blade slots to provide a supply of oil under pressure to hold the blades to their outmost positions, and further provides a circulating system to regulate the volume of oil to each blade in accordance with the varying lengths of the strokes of the blades. As the air pressure in the chamber varies so does the pressure of oil vary and in this manner the pressure on the blades is varied. This situation obtains as regards the pressure of the oil against the free end of the lever seal 40 also. The greater the air pressure in the chamber the greater the inward pressure against the free end of said lever, and vice versa. The pressure of the oil against the inner ends of the'blades causes the central blade sections to bear against the shoulders 33 of the end sections of the blades and spread them into sealing engagement with the endwalls of the casing.

In Figures 5 and 6 a modified form of blade is shown comprising a central section 44 having recesses 45 and 46 therein extending to the ends thereof and having its top outer corners 'cut di vergingly in relation to one another to provide shoulders 41, and sections 48 and 49 adapted to be placed at opposite ends respectively of the section 44 and having recesses 4 registering with the corresponding recesses 45 and 46 of the said section 44 and having their inner top corners cut away diagonally to provide shoulders 50 cooperating with the shoulders 41 to provide inverted V-shaped devices, and spreader sections 5| and 52 having reduced portions 53 and 54 respectively adapted to loosely fit the recesses in the central and end sections, and further having thickened inverted V-shaped portions 55 and 56 adapted to bear against the V-shaped devices formed by the shoulders 41 and 50 whereby downward pressure on the said spreader sections will cause outward movement of the end sections. Suitable oil grooves 51 may be provided in the various sections.

Figures 7 and 8 show a still further modification of the blade, which in this instance consists of two sections 58 and 59 adapted to be placed in endwise overlapping engagement, with the overlapping portions reduced in thickness, the said sections having endwise registering interior slots 60 and SI into which is fitted loosely a spring 62.

In Figures 9 to 11 a modified oil supply system is shown in which the rotor shaft 8 is provided near its inner end with inwardly extending openings 63, 64, 65 and 66 registering with oil passages 61, 68, 69 and respectively which extend longitudinally of the rotor to substantially the centre thereof and at their ends register with oil passages 12, 13 and 14 which extend outwardly and lead into the respective blade slots. In this variation and modification without departing.

modification an oil pipe I! leads upwardly from the oil reservoir and through the hub 1 in alignon the rotation of the rotor each of the latter openings will successively receive a charge of oil which will be passed to the respective blade slots, In this showing of the invention a groove 16 is cut in the end wall of the casing, similar, to the groove II with the exception that instead of said groove being continuous, as is the said groove l5, it is closed at the top side of the casing, as indicated by the numeral 11, for a distance at the high compression side of the casing, whereby the oil at the sealing point cannot escape other than into the blade slot of the blade passing the sealing point, and in this way additional pressure is applied to each blade as it approaches and passes the sealing point, so as to absolutely prevent escape of the air or gas from the high compression to the low compression sides at this point.

In Figure 12 a modified form of oil feed to pro vide pressure against the sealing lever is shown.

It is obvious that the amount of oil on the top side of the sealing lever determines the pressure on said lever and it is desirable that means be provided for varying the pressure under different conditions. To this end the casing above the lever is provided with a removable section 18 adapted to be secured by suitable means, and in the space therebelow so made accessible, is inserted a block 80 having a recess ill in the under face thereof in which is inserted a bar I2. The bar 52 is of lesser depth than the recess to provide an oil chamber thereabove to which oil is supplied from the oil feed pipe, whereby to provide pressure on the bar and consequently on the lever 40 therebelow.

By this construction the extent, and the point, of pressure on the lever 40 can be altered by simply removing the block 80 and the bar 82 and substituting another block having a recess of greater, or lesser, length and inserting another bar to fit the new block. This construction also permits 01' shortening or lengthening the leverage.

While I have illustrated and described the present preferred forms of construction for carrying out my invention, these are capable of from the spirit of the invention. I,therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as, come within the scope of the appended claims.

What I claim is:

1. A rotary compressor comprising a casing having an inlet and an outlet, a recess in the inner wall of said casing between said inlet and outlet, a rotor eccentrically journalled in said casing with the periphery of said rotor adjacent the inner wall of said casing substantially at said recess, spaced slots extending inwardly from the periphery of said rotor, blades reciprocally mounted in said slots for engaging the inner wall of said casing, a sealing member pivotally mounted at one end in said recess to cover the mouth thereof and to engage the periphery of said rotor, and means for supplying fluid under pressure to said recess behind said sealing member to swing said sealing member into sealing engagement with said rotor.

2. A rotary compressor comprising a casing having an inlet and an outlet, a recess in the inner wall of said casing between said inlet and outlet, a rotor eccentricaliy journalled in said casing with the periphery of said rotor adjacent the inner wall of said casing substantially at said recess, spaced slots extending inwardly from the periphery of said rotor, blades reciprocally mounted in said slots for engaging the inner wall of said casing, a sealing member pivotally mounted at one end in said recess to cover the mouth thereof and toengage the periphery of said rotor, and means for supplying fluid under pressure the inner wall of said casing substantially at said recess, spaced slots extending inwardly from the periphery of said rotor, blades reciprocally mounted in said slots for engaging the inner wall of said casing, a sealing member pivotally mounted at one end in said recess to cover the mouth thereof and to engage the periphery of said rotor, a chamber in communication with said outlet for receiving compressed fluid, an oil reservoir in said chamber to be subject to the pressure of the compressed fluid, and an oil passage from said reservoir to said recess behind said sealing member for supplying oil under pressure to press said sealing member against said rotor in accordance to the discharge pressure of said compressed fluid.

4. A rotary compressor comprising a casing having an inlet and an outlet, a recess in the inner wall of said casing between said inlet and outlet, a rotor eccentrically journalled in said casing with the periphery of said rotor adjacent the inner wall of said casing substantially at said recess, spaced slots extending inwardly from the periphery of said rotor, blades reciprocally mountd in said slots for engaging the inner wall of said casing, a, sealing member pivotally mounted at one end in said recess to cover the mouth thereof and to engage the periphery of said rotor, a chamber in communication with said outlet for receiving compressed fluid, an oil reservoir, and oil passages from said reservoir to said recess and said slots for supplying oil under pressure behind said sealing member and said blades respectively to bias said sealing member into sealing engagement with said rotor and to bias said blades into sealing engagement with the inner wall of said casing, said oil reservoir being in said chamber to be subject to the pressure of the compressed fluid whereby said oil is supplied through said assages in accordance with the discharge pressure of the compressed fluid.

5. A rotary compressor as defined in claim 4 wherein said blades are provided with grooves longitudinally in their lateral edges for the reception and passage of oil from said slots to form an oil seal with said casing.

6. A rotary compressor comprising a casing having an inlet and an outlet, a recess in the inner wall of said casing between said inlet and outlet, a piston-like element slidable in said recess, a rotor eccentrically journalled in said casing with the periphery of said rotor adjacent the inner wall of said casing substantially at said recess, spaced slots'extending inwardly from the periphery of said rotor, blades reciprocally mounted in said slots for engaging the inner wall of said casing, a sealing member pivotally mounted at.

one end in said casing over said recess for engagement by said piston-like element and to engage the periphery of said rotor, and means for supplying fluid under pressureto said recess to displace said piston-like element and thereby swing said sealing member into sealing engagement with said rotor.

7. A rotary compressor comprising a casing having an inlet and an outlet, a recess in the inner wall of said casing between said inlet and outlet, a block removably seated in said recess a d having an opening of selected size, a piston- I like element slidable in said opening, a rotor eecentrically journalled in said casing with the periphery of said rotor adjacent the inner wai1 of said casing substantially at said recess, spaced slots extending inwardly from the periphery of said rotor, blades reciprocally mounted in said slots for engaging the inner wall of said casing, a sealing member pivotally mounted at one end in said casing over said recess for engagement by said piston-like element and to engage -the periphery of said rotor, and means for supplying fluid under pressure to said opening to displace said piston-like element and thereby swing'said sealing member into sealing engagement with said rotor.

THOMAS L. HICKS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 40,008 Adancourt Sept. 22, 1863 54,581 Morris May 8, 1866 228,344 Hallner June 1, 1880 724,132 Smith Mar. 31, 1903 1,233,855 Eidson et al July 17, 1917 1,776,921 Moessinger Sept. 30, 1930 2,020,987 Ayres Nov. 12, 1935 2,050,533 Huff Aug. 11, 1936 2,057,381 Kennedy et al. Oct. 13, 1936 2,149,337 Deming Mar. 7, 1939 2,275,774 Kraissl Mar. 10, 1942 FOREIGN PATENTS Number Country Date 115,778 Switzerland Sept. 16, 1926 186,271 Great Britain Sept. 28, 1922 257,706 Italy Mar. 15, 1928 778,346 France Dec. 22, 1934 850,991 France Sept. 25, 1939

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