US3180569A

US3180569A - Cooled rotary pump

Info

Publication number: US3180569A
Application number: US196267A
Authority: US
Inventors: Rolf A Bielefeld
Original assignee: Gast Manufacturing Corp
Current assignee: Gast Manufacturing Corp
Priority date: 1962-05-21
Filing date: 1962-05-21
Publication date: 1965-04-27
Anticipated expiration: 1982-04-27

Description

April 27, 1965 R. A. BIELEF ELD 3,180,569

COOLED ROTARY PUMP Filed May 21, 1962 5 Sheets-Sheet 1 [F1 1 IV 12 /0 /45 J0 30 an M [L "2& 1 mi Q ,zW

April 27, 1965 R. A. BIELEFELD COOLED ROTARY PUMP April 27, 1965 R. A. BIELEFELD COOLBD ROTARY PUMP 5 Sheets-Sheet 3 Filed May 21, 1962 INVENTOR. A 01; 4. fl/AZEFEM BY Q0 ;W

April 27, 1965 R. A. BIELEFELD 3,180,569

COOLED ROTARY PUMP Filed May 21, 1962 5 Sheets-Sheet 4 INVENTOR. A0ZF A. BAH/EH9 April 27, 1965 R. A. BIELEFELD COOLED ROTARY PUMP 5 Sheets-Sheet 5 Filed May 21, 1962 INVENTOR. P00 '4. 5751:7220

QVAV

ATTOAA/EYS controlled peripheral pressure.

United States Patent'O 3,180,569 CQOLED ROTARY PUMP Rolf A. Bielefeld, Saint Joseph, Mich, assignor to Gast Manufacturing Corporation, Benton Harbor, Mich, a

corporation of Michigan Filed May 21, 1962, er. No. 196,267 11 Claims. (Cl. 230-209) This invention relates to rotary pumps, and more particularly to air-cooled, rotary vane pumps for gaseous media having controlled gas inlet and exhaust features.

The efliciency and dependability of a rotary pump, especially a rotary vane pump, depend to a large extent upon low operating temperatures of the pump. it is well known to those in the field that rotor hub temperatures often reach undesirably high values because of the inability of the hub to effectively dissipate its heat to the outside. Only a limited amount of the heat in the hub is conducted out through the end shafts. Moreover, this heat conducted through the end shafts tends to overheat the bearings supporting the end shafts in the pump housing end plates.

The bearings mounted in the end plates are further subjected to additional heat caused by frictional contact of the high speed rotating pumping vanes against the inner walls of the end plates. The adverse effect of these factors is further magnified by the present lack of a satisfactory housing structure to achieve proper cooling of the exterior of the entire pump in an economical manner.

7 Another shortcoming of present rotary pumps is the lack of a simplified positive control system of the pump inlet and exhaust gases to enable proper filtering without substantially detracting from the pumping eflicie'ncy, or to enable rapid operational changeover of the unit from a filtered compressor to a mufiled vacuum pump.

Another feature of conventional rotary vane pumps which detracts from efiiciency and output is the high pressure gaseous blow-byor slippage which passes beneath the lower edges of the vanes between the end plates and the ends of the rotor hub. This slippage creates operational losses and raises internal operation temperatures considerably.

To obtain optimum elliciency, rotary vane pumps must not only make an effective seal against the end walls, but also must seal effectively against the peripheral housing wall. The pressure of the individual vanes against the housing Wall must at all times be great enough to keep the vanes in contact with the peripheral wall. Yet, the pressure of the vane against the peripheral housing wall must not be so great as to cause undue wear of the vanes. Various methods of pneumatically balancing or cushioning the vanes are presently utilized in efforts to accomplish this However, these conventional methods generally lack a really accurate or controlled vane cushion since the gaseous pressures under the vane tend to vary largely. I

It is an object of this invention to provide a rotary pump withgreatlyimproved efiiciency and reliability over an extended period of operating time due to a uniquely cooled structure. The interior of the pump which includes the rotor hub and the end shafts is efifectively cooled. Further, the hearings in the end plates around the end shafts are maintained in'a cool state by special end plate cooling. Moreover, the exterior housing of the pump is efiiciently and economically cooled by a unique flow pattern of cooling air. In addition, the internal cooling, end plate cooling and exterior housing cooling are all eifected hlddhdh Patented 2?, i955 by simultaneously blower means operated directly on the end shafts of the pump. The end plates not only maintain the bearings in a cooled condition, but also have a heat flow restricting darn structure substantially reducing the conduction of frictional heat from the inner walls of the end plates to the portions of the end plates mounting the bearings.

It is another object of this invention to provide a pump 7 having a base cons ruction which constitutes a manifold for directing pump inlet and outlet gases, for filtering or mufiling gases, and for directing cooling air. The manifold is reversible with respect to the pumping unit to enable a special filter-receiving chamber (when the unit serves as a compressor) toalternately constitute a mufflerreceiving chamber for use with the unit when operating as a vacuum pump. The manifold receives and directs air propelled by the blower on the end shaft.

it is another object of this invention to provide a vane type pump having an accurately controlled air cushion under the base of each vane to provide optimum constant contact of the outer vane edge against the inner housing peripheral wall. The controlled air cushion enables accurate cushion pressures under the vane even though the cushioned gas changes in temperature during the cycle.

These and other objects of this invention will be apparout upon studying the following specification in conjunction with the drawings in which:

FIG. 1 is a side elevational view of the novel pumping apparatus;

PEG. 2 is an end view of the apparatus as viewed from plane Hll of FIG. 1;

PEG. 3 is a side elevational sectional view taken on plane IlI--Ill of FIG. 2;

FIG 4 is a sectional view of the apparatus taken partly on plane IV-IV and partly on plane IV'-IV' ofFIG. 1

showing the apparatus adapted to operate as a compressor;

PEG. 5 is a fragmentary sectional View showing the pump rotor and vanes in the housing shell and showing the novel vane cushioning means;

FIG. 6 is a top plan view of the manifold portion of the base of the apparatus;

FIG. 7 is a side elevational slightly enlarged view of the complete base;

FIG. 8 is an end elevational viewof one of the end plates adjacent the fan of the apparatus illustrated in FIG. 3;

FIG. 9 is an end elevational view of the end plate adjacent the drive pulley illustrated in FIG. 3;

FIG. it) is a fragmentary partially sectioned view of a slightly modified double blower arrangement which can be used instead ofthe single blower illustrated in FIG. 3; and

P16. 11 is a fragmentary sectional view of the apparatus with the pump reversed on the base to enable operation as a vacuum pump.

Basically, the invention comprises a rotary pump including a hub and attached end shafts having an elongated cooling fluid passageway therethrough. Cooling air is drawn through the passageway by a. blower or fan means mounted on the. end shaft means. The blower means may be of the centrifugal type. It can be mounted over radial outlet openings in one end shaft, or may be mounted to suck air out an annular passageway in an end shaft.

The pump has an outer shroud over the'pump housing, including an end air inlet or one end adjacent a fan, and" enclosed transverse fins on the housing to direct the cooling air flow. The fins are spaced from the shroud on the cooler, low pressure zone of the pump to allow air entering into the end shroud opening to flow into the intermediate transverse spaces between the fins. The fins are inclose proximity to the shroud adjacent the hotter, high pressure zone of the pump housing to uniformly cool it by forming substantially closed conditions between the fins.

The housing end plates include circumferential, coolingfluid passageways around the outer periphery of the bean ings mounted in the end plates. The circumferential passageways receive cooling air from the fan on the end shaft. The inlet to the circumferential passageway is divided by a baffle to form separate cooling air pathscausing high-velocity, low-resistance cooling-air flow over the hotter, high pressure zone of the pump, and causing separate higher-resistance, cooling-air fiow over the cooler low pressure zone of the pump.

Each circumferential passageway in the end plates includes an annular, radially-inwardly-directed recess or cav-. ity portion between the inner wall of the end plate and the portion of the end plate .in which the bearing is mounted. This provides a heat-flow restricting dam substantially lessening the conduction of heat from the inner wall of the end plate to the bearing.

A unique combination supporting base and manifold is removably attached to the bottom of the pump and in cludes ports and passagewaysto direct cooling air to the end plates, to direct and filter inlet air or gas to the pump,

and to direct compressed outlet air or gas. The manifold is readily reversible to enable rapid conversion of the pump from a compressor'to a vacuum pump, with the filter-receiving chamber then comprising a mufiler-receivpreferably include a cool-air inlet port allowing entry of air under the extended vanes due to their position adja-'' cent the air inlet portion of the pump, a bleed port located part-way around the pump and communicating with the slots under partly depressed vanes, and an exhaust port spaced operationally beyond the air outlet for the pump 'to communicate with the slots under completely depressed vanes to exhaust the heated, compressed cushioning air. These allow the influx of cool cushioning air during each cycle, and accurate control of the air cushions.

External cooling Referring now to the drawings, pumping apparatus 14) as externally viewed includes a'combination manifold and base 24, enclosing shroud 12, and a drive pulley 18 mounted .on an end shaft 16. The term entire base is intended to normally include the manifold portion.

The shroud 12 may comprise pre-formed thin material 7 such as sheet metal. shells secured together by bands 20 (FIG. 1) around pairs of facing semi-circular projections forming posts 22 (see FIGS. 1 and 4); It may be formed of one continuous piece instead of two, and may include a portion serving as a guard over pulley 18. It fits down around the mani fold part of the base as in FIG. 4 to enclose the' apparatus. The shroud hasa plurality of openings forair inlet and outlets as explained hereinafter.

The base includes a chamber for receiving a filter 26- when the unit is used as a compressor (FIG. 4) or a muliier 326 connected together. when the unit is used as a vacuum pump (FIG. 11). The base may be formed of two parts by suitable means such as studs 202 (FIG. 2) ort-the -eoin piete base maybe of an integral construcnjjsh Enclosed within shroud l2 and mounted upon the base as by studs 2th) is the main pump housing 23 (FIG. 3).

It is shown formed of two half (The unit will first bedescribed as a compressor.) It has a plurality of transverse fins .30 on its outer periphery. On the low pressure air intake side of the pump (the left side in FIG. 2 and the right side in FIG. 4), fins 30 are substantially spaced from shroud 12 to provide an air flow space 32 through which cooling air entering the axial end opening 33 (FIG. 3) in the shroud, may fiow after passing through the outer portion 106 of centrifugal fan 40. Air drawn through'opening 38 passes through fan 40, through space 42, then space 32. Here a change of direction from longitudinal to transverse occurs. The air then flows between the fins in spaces 48 '(FIG. v3). Pins 30 are in close proximity to shroud 3.12 on the opposite side of the pump where the air pressures inside the pump are greater. (as explained hereinafter) andthus the temperature is higher. The spaces between adjacent fins '30, the pump housing external surface and the inner surface of the shroud combine to form substantially closed conduits for uniformly distributingthe cooling air over the hot portion of the pump. After theair passes between the fins 30 under the bottom andaround the top of the pump (FIG. 3), it flows out .outlet port 50 in the side' of the shroud (FIGS. 1 and 4).

Internal cooling Referring to FIG. 3, pump housing 28 includes 'a generally cylindrical central housing'portion 7d, a first end plate 72 on the drive end, and a second end plate 74 on the fan end of the pump. Within the housing is rotatably mounted a rotor means including central rotor hub '76,

integral end shafts

78 and 80, and 'slidably mounted vanes 82 (FIGS. 3 and 4). The vanes 82 fit in generallyradially oriented slots extending the lengthof the hub, such that the ends of the vanes contact the inner-

walls

84 and 86 of the end plates '72 and 74. The vanes also contact the inner peripheral wall 88 of the cylindrical portion of the housing during operation of thepump.

The end shafts arerotatably mounted in the end plates by suitable bearings, 90 and 92with

adjacent seals

94 and 96. The end plates include'caps and 112.

'In the form of'the invention illustrated in FIG. 3, on end shaft 86 is attached a centrifugal fan 40 which includes an outer section 100 and an inner section 102, divided by a partition 194. The fan has a centrifugal action. Fan 40 is secured to end shaft 80b a collar 114 and set screw 116, orother equivalent-means- In order to provide proper cooling of the internal structure of the pump, the end shafts 78 and ,Sdand the'hubl76 are provided with a centralpassagewaylZtl 'andradial outlet ports 12 2 in end shaft 30.. These ports communicate with inner section 162 of fan 4tl'to enable air to be drawn through passageway 126, exit at ports 122, and then into passageway 42 between the housing and the shroud to mix with air introduced at port 38 of the shroud. .This interior passageway thus cools both end shafts adjacent bearings 9 and 92 and also conducts heat away from the central rotor hub for optimum efliciency. It will be noted that the cooling occurs simultaneously with operation of the pump since the fan is mounted directly upon the end shaft, and that the same fan cools both the'interior and the exterior.

Instead of the singlefanshoWninFIG. 3 and described above, it is sometimes. desirable to utilize fan 4% of a conventional construction (see FIG. 10) on end shaft 80 to direct air around the outside of the .unit, and to utilize a separatecentrifugal fan 3% formed integrally With.

shiver 18 to suck. air through passageway inthe opposite direction. In this instance an axial inlet 3W2 in end shaft 80 will suffice instead of'radial openings 122;

. partition 164 on the manifold base.

Cooled end plates The

end plates

72 and 74 include circumferential passageways 131i and 132 respectively, encircling bearings 91 and 52. A portion of the cooling air entering at 33 flows through these circumferential passageways to cool the end plates. These passageways are enclosed by end caps 110 and 112 attached to the end plates as by bolts 111. More specifically, air entering at 38 (FIG. 3) passes downwardly into space 149 and is propelled by the outer section 169 of the fan into passageway 142 over the deflecting diagonal partition 141 (FIG. 3) on the manifold base. It then flows into passageway 132 and out the lateral exhaust port 14-8 (FIG. 2). It will be noted from FIG. 2 that a baffle 150 divides the inlet to this circumferential passageway 132 into two portions. Part of the air flows (to the right) through a short, low flow-resistance, radial segment comprising about 90 of the circumferential passageway and out through the outlet port 148. Another portion passes (to the left) around the longer, higher-resistance segment comprising about 270 of the passageway and out the outlet port 148. The low resistance segment is adjacent the high compression Zone of the pump which is the hottest. This Zone demands more coolling than the lower compression zones which are cooled by the second flow path. Openings close to the heat dam are provided in the radial support flanges or baflies 152 and 154 to allow the cooling air to flow through them in the long segment. I

Not only is end plate 74 cooled in this fashion but also end plate 72, The cooling air entering at port 32 (FIG. 3) and flowing into space 140 passes partially through open space 169 between the supporting bracket or stand 14 and lower base portion 24. It flows clear under the pump and through space 162 over the diagonal deflecting It then flows into circumferential passageway 1311 where the flow is divided into two paths, one being a short, low flow resistance path over the high compression hot zone of the pump, and the other being a higher resistance longer path over the cooler low compression portions of the pump just as in the opposite end plate. The air then emerges at exhaust port 176 (FIG. 1). The walls ofthe exhaust port 170 may be integral with either the end plate or shroud.

To further protect bearings 90 and 92 from heat created by frictional contact of the ends of the sliding vanes 32 with the

inner walls

84 and 86 of the

end plates

72 and 74, a heat-flow restricting damming structure is provided in the end plates as shown in FIG. 3. This comprises annular, radially-inwardly directed cavities or recesses 176 and 178 in

end plates

72 and 74, respectively extending a substantial distance between the bearing-receiving recess in the end plates and the inner wall of the end plate. Cooling air circulating through the

circumferential passageways

130 and 132 thus effectively conduct the heat away from the inner end plate walls. This constitutes in effect a heat-flow damming structure since only a small metal partition 23 exists through which heat can be conducted.

Combination manifold base The base not only comprises a removable mounting means for the pump, but it also constitutes a manifold for directing air flow and for receiving a filter or mufiler. The detailed structure of the manifold base can be seen more clearly in FIGS. 6 and 7. It comprises essentially a generally rectangular, lower portion 14 and an upper portion 24- thereabove and having an open bottom. It inber to the pump inlets 2443 and 242 (FIGS. 8 and 9) in the end plates when the unit is adapted to operate as a compressor as shown in FIG. 4. This allows air or gas passing through the filter to pass into the pump to be compressed. The other two

openings

214 and 216 in the base constitute outlet ports adapted to communicate with the pump outletpassageways 246 and 243 in the end plates. This allows compressed air to pass from the pump into a small end chamber 222 in the base (FIG. 6) and then out through compressed gas-exhaust port 220 to which a suitable conduit (not shown) may be attached. To separate compressed gas in chamber 222 from the uncompressed inlet gas in the filter chamber 2% under partition 203, an elongated vertical partition 224 is provided to extend across the width of the base. i

The portion 230 of partition 20? adjacent outlet port 220 and that portion 232 on the opposite side are raised at the edge, and they tilt downwardly on an angle toward the center (see FIGS. 2 and 7). provide smooth deflecting surfaces for the cooling air passing beneath the housing between fins 3119 as explained heretofore.

Ports 211i and 212 in the base and

ports

214 and 216 cooperate respectively with the inlet and outlet passageways in the end plates of the pump housing, in the following manner. Referring to FIGS. 8 and 9

end plates

72 and 74 are shown without their end caps 11th and 112 so that radial bracing

flanges

150, 152 and 154 are shown clearly. The

end plates

72 and 74 have inlet passageways 24d and 242 respectively, and

outlet passageways

246 and 248 respectively.

When air is to be compressed, it is supplied to the pump by being drawn through port 38 by fan 40 and downwardly through space and space 161) (FIG. 3) and then up through filter 26. It then kows through openings 219 and 212 in the base 24, up through inlet ducts 24d and 242 in the end plates and between the vanes 82 inside peripheral wall 83. It is then compressed by the rotor means and discharged through ducts 244 and 246 in the end plates, down through

openings

214 and 216 in the into chamber 222, and out through discharge port 220.

When a vacuum pump operation is desired (see FIG. 11) the novel manifold structure enables the unit to be quickly changed from the filtered compressor to-a muffled vacuum pump unit. This may be elfected by simply removing bolts 2% out of the threaded base openings 251, rotating the pump with respect to the manifold base, and replacing bolts 2%. The filter chamber 2% thereby becomes a mufiler-receiving chamber by sliding out filter 26 and inserting mufiler 326.

In the operation of the unit as a vacuum pump, it will noted that the rotor 76 and vanes are reversed with respect to the base so that port 2213 becomes an inlet port. The chamber or line to be evacuated is thus attached over port 220. The evacuated gas then passes into port 220, up passageways 249 and 242, around rotor 76 in a clockwise direction as viewed in FIG. 11, down

passageways

246 and 248 and into the chamber above the mufller 326. This muffler may contain conventional resonance baffles 321) or absorption structure 322 such as steel wool. The muffler includes a lower partition 324 preventing the hot evacuated gases from passing into chamber 161? where cooling air is flowing to end plate 72 (FIG. 3). Thus the evacuated hot gases pass out the sides of the mufller as indicated by the arrows in PEG. ll.

Controlled vane cushion In FIG. 5, thefragmentary sectional view shows the pump housing (without its cooling fins) with the inner peripheral wall 88 defining the cylindrical chamber in which rotor 30%? is eccentrically mounted. The rotor axis is parallel to the axis of the cylindrical chamber 83. Formed in the rotor over the length thereof is a plurality of generally radially positioned vane-receiving slots 362. Each of these slots preferably has an enlarged cavity 324 at the base thereof as claimed in my co-pending application Serial No. 181,618, filed March 22, 1962, now atent No. 3,138,321. This cavity 3194 may, in this inven- Surfaces 23d and 232 to a completely depressed position as shown by vane "82. When the depressed vane begins to extend again, it passes the air inlet port 244 inciudingrrecess 241 in the end plate. The vane continues to draw in airuntil it reaches the position of vane 82. As these vanes pass around with the rotor hub, they are slowly depressed into their slots as the air is compressed between therotor'hub and the Wall 88. When the exhaust port 246 is reached, compressed air is expelledwhile the vane continues to'be depressedinto the slots to its maximum depressed position as at vane 82', and the cycle then begins again. I

Duringoperation, the movement of each vane in its respective slot causes sequential compression and evacuation of the air or gas trappedunder the vane. The pressure under'the vane tends to exaggerate vane tip pressure against the housing wall. Vacuum tends to keep the vane from continuous contact with the wall. methods have been denied in attempts to dynamically balance the vane including arcuate channels in the end plates or rotor ends, and including radial passageways in or adjacent the vane. At best, these allow constant pressure equalization, but do not provide accurate vane tip pressure control over the critical portions of the vane movement cycle. More specifically,'it has been found that the vanes tend to move out of contact with the peripheral housing wall at and adjacent (just beyond) the exhaust port'of the pump. Consequently, it hasbeen found to be greatly advantageous to achieve larger vane 32d of the vane cavities are not exposed to a vent as the vane tip approaches and passes exhaust port 246 (this exhaust port may be either in the end plates, the peripheral housing wall, or both). Since the vane is compressing gases in the slot base 324), a pressure cushion is created forcing the vane tip into a greater pressure contact with the wall 88. This continues as the vane passes the exhaust port until it is adjacent the inlet port i.e. where it begins to extend out of its slot. At that time, slot base 329 (preferably wall 304) communicates with channel 322 and outlet port 321 to exhaust the hot compressed cushion air into the end plate passageway (or if desired to the atmosphere). If the unit is operating as a vacuum pump, on the other hand, port 321 allows entry of atmospheric air into the slot base which will have beenlargely evacuated'by escape of the cushion alongside the vanes.

Thus the new air provides pressure for continuous vane tip contact.

As the-vane continues to move with the rotor with the unit operating as a compressor, slot base 326 next communicates with arcuate channel or passageway 324- which way around as the vane is in the initial depression stages with the slot base chamber being smaller. The exact location of the last portion of this channel 326 enables an exact adjustment of the volume of gases in the vane cushion. This is caused by a limited bleeding or venting. The small amount ofair exchange enables an exact adjustment Various of the cushion to provide the optimum cushioning in the highcornpression zone of the pump. As -stated, the exact location of one-or more'bleed ports determines thefinal cushion pressure. These threeports thus cooperateto first take in cool air, accurately bleed off a small percentage of the warm, partially compressed airto'set the'air cushion at the exact desired amount, and. then exhausting the compressed hot cushion air to enable it to againreceive cool cushion air. In the pump illustrated, each of the ports 3231, 323 and-325 cooperating respectively withthe

passageways

322, 324 and 325 is preferably formed in the end plate as in end plate '74 in FIG. 3. They communicate through theannular recess 178 to the circumferential passageway 132. The other end platc 72 can be provided with similar parts. As shown more specifically in PEG. 2, the cool air inlet 323 is adjacentthe start of the 270 passageway, the bleed port 325 is part way around the 270 passageway, and the exha'ustport 321 is associated with the flow path in the circumferential passageway. If desired, a pump may utilize thisporting feature without end plate passagewaysby porting to theatmosphere.

Conceivably

channels

324 and 326 can be joined into one continuous passageway to both provide cool inletcushion air and bleed it to the proper volume before the'vane causes cushion compression. However, it has been found desirable to provide a non-ported'area. 331 between the

passageways

324 and 326, and located such. as to eliminate slot base venting just before the vane passesthrough its most extended position. 7 The vane, as it extends the final amount, thereby causes a small vacuum to occur in the slot base, tending to reduce vane-tip contact pressure at this point and thereby reducing wear considerably; Thus, by using one or more ports at specific locations to'vent the vane cushions only at crucial moments when they are under specific different pressure potentials, excellent control of venetip pressure is achieved. The results achieved with the-unit operating as a compressor are (l) a pressure cushion when the vane. passes is most depressed in the slot to keep it in firm contact with thewall thereby preventing slippage, (2). accurate bleeding and control of this pressure cushion, (3) complete aspiration of cushion cool air witheach cycle, and (4) a vacuum cushion when the vane is in its most extended position to minimize wear.

the pump and the exterior of the bearings, and supplies air to be compressed bypassing it through filter 26 and up through the manifold openings. The manifold directs the compressor inlet and outlet air or gas through filter 26 and

openings

210, 212, ZM-fand 216, it directs the end plate air. flow. over surfaces 141'and 164, and it creates a smooth flow under the pump exterior with surfaces 2 3% and 232'. Reversal of the manifold allows operation of the compressor as a vacuumpump during which the manifold base directs the evacuated gas through port 22%), into the pump chamber, and through themuflier 32-. The unit is capable ofremarkableefiiciency due to its cool operation, and also due to the controlled vane-contact pressure. It is relatively compact in spite of its elaborate cooling system and manifolding characteristics.

Certain obvious modifications of this-apparatus within the inventive principles taught may bemade'without departing from the scope of the inventiom Such modifications are deemed part of this invention, which'is to be limited only by the appended claims and the reasonable ity of transverse cooling fins and intermedai't'e spaces on the housing exterior; a shroud generally around said housing and including cooling air inlet and outlet means, and said shroud and fins being relatively spaced from each other adjacent said low compression zone to allow air to pass from said shroud inlet to the spaces between said fins;-said shroud and fins being closely positioned with respect to each other adjacent said high compression zone to cause said spaces to form substantially closed passageways whereby air can be uniformly directed over the heated high compression area for effective cooling; and cooling fan means adapted to propel air over said fins within said shroud.

2. A rotary compressing pump comprising: a housing including end walls; a rotatable rotor hub within said hous ing including slidable vanes and having end shafts; said rotor being eccentrically mounted Within said housing to create a low compression pumping area and a high compression pumping area; a plurality of transverse fins and intermediate spaces on the housing exterior; a shroud generally around said housing and including cooling air inlet means on one end, and outlet means adjacent said high compression area; said transverse fins being displaced toward the side of said housing having said high compression area into close relationship with said shroud to define a plurality of substantially closed cooling passageways between said fins, shroud, and housing to uniformly conduct cooling air over said high compression area; and a cooling fan adapted to propel air over said fins Within said shroud.

3. A rotary compressing pump comprising: a housing including end walls; a rotatable rotor hub within said housing including slidable vanes and having end shafts; said rotor being eccentrically mounted within said housing to create a low compression pumping zone and a high compression pumping zone; a plurality of transverse films and intermediate spaces on the housing exterior; cooling fan means mounted on at least one of said end shafts; a shroud around said housing; an air inlet in said shroud adjacent said fan; a passageway through said end shafts and said hub including outlet means in one end shaft adjacent said fan means; said shroud and transverse fins being relatively spaced from each other adjacent said low compression zone to allow air down through said passageway and through said air inlet to pass into said spaces between said fins; said shroud and fins being closely positioned with respect to each other adjacent said high compression area to cause said spaces to form substantially closed conduits; and outlet means in said shroud adjacent said conduits.

4. A rotary pump comprising: a pump housing; rotatable pumping means in said housing including rotor means and end shafts on said rotor means; cooling fan means mounted on at least one of said end shafts and adapted to rotate with said shaft; shroud means spaced from and around said housing including air inlet and outlet means; cooling fins on said housing to direct air flow around and conduct heat from said housing; an air flow passageway through said end shafts and said rotor means including outlet means adjacent said fan means; said housing including end plates; each of said end plates having a circumferential cooling fluid passageway including an inlet and outlet within the enclosure of said shroud; and said fan means being operably associated with said fins, said air flow passageway, and said circumferential passageway to simultaneously cool the pump housing exterior, the pump interionand the end plates, while the pump is in operation.

5. A rotary pump comprising: a housing means including an inner peripheral wall and a pair of end plates; rotor means mounted in said housing and including end shafts supported by and extending into said end plates; bearing means mounted in said end plates for said end shafts; circumferential cooling fluid passageways around said bearing means in said end plates; air directing shroud lb means around said pump; and blower means mounted on at least one of said end shafts and adapted to propel cooling air directed by said shrouds into said circumferential passageways to maintain cool bearings.

- 6. A rotary pump comprising a housing including two end plates; eccentrically mounted rotor means in said housing including end shafts rotatably mounted in said end plates; said pump including a pump fluid inlet adjacent the relatively large low compression zone of the pump and including a compressed fiuid outlet adjacent the relatively small high compression zone of the pump; a cooling fluid passageway in each of said end plates substantially encircling said end shaft; a cooling fluid inlet means to each of said passageways between said high and low compression zones; andeach of said cooling fluid inlet means being divided to create a high velocity,

low-fiow--resistance coolant flow path past said relatively small, high compression zone, and to create a separate, lower velocity, higher-fiow-resistance coolant flow path past said relatively large, low compression zone.

7. A rotary pump comprising: a housing means including an inner peripheral wall and a pair of end plates; rotor means mounted in said housing and including end shafts supported by and extending into said end plates; bearing means mounted in said end plates for said end shafts; circumferential cooling fluid passageways around said bearing means in said end plates; each of said end plates having an inner wall in rubbing contact with portions of said rotor means; and each of said passageways including a circumferential, inwardly radially directed cavity extending between said bearing means and said inner wall thereby forming a heat-flow restricting darn.

8. A combination manifold base for a rotary compressor pump having inlet and outlet ports adjacent the bottom thereof, comprising: a base housing including means for connecting and aligning said base to a pump; an air inlet in said base; a filter-receiving chamber in said base adjacent saidair inlet; first air porting means in the upper portion of said base adapted to communicate with the inlet port of a rotary pump arid with said filterreceiving chamber; second air porting means in said base adjacent the upper portion thereof and adapted tocornmunicate with the outlet port of a rotary pump; and passagewa means and an exhaust outlet in said base communicating with said second air porting means to control the pumped air.

9. The base in claim 8 wherein said first and second air porting means are generally symmetrically arranged, wherein said base is removably attachable to the pump, and wherein said filter retaining chamber is adapted to retain a muliler such that said base may be rotated to enable said pump to operate as a vacuum pump.

10. A rotary pump comprising a housing including two end plates; pumping rotor means mounted in housing between said end plates and having a pair of end shafts in bearing contact with said end plates; inlet and exhaust ports in said housing adjacent the bottom thereof; a generally flat manifold under said pump and removably secured thereto; said manifold having a lower air inlet and a filtering chamber communicating therewith; a pumping fluid outlet in the top of said manifold communicating with said filtering chamber and said inlet port in said pump housing; an exhaust entry port in the top of said manifold communicating with said pump exhaust port in said hous-. mg; an exhaust chamber in said manifold communicating with said exhaust entry port and having a pressure port leading outside said manifold; cooling air directing surfaces on said manifold associated with said end plates of said housing to direct cooling air thereto; and blower means capable of propelling air to said cooling air directing surfaces and said manifold lower inlet.

11. A rotary pump comprising a housing including two end plates; pumping rotor means mounted in said housing between said end plates and having a pair of end shafts in bearing contact with said end plates; inlet and exhaust l3; ports in said housing adjacent the bottom thereof; a generally flat manifold under said pump and removably secured thereto; said manifold having a lower air inlet and a filtering chamber communicating therewith; a pumping fiuid outlet in the top of said manifold communicating with said filtering chamber and said inlet port in said pump housing; an exhaust entry port in the top of'said manifold communicating with said pump exhaust port in said housing; an exhaust chamber in said manifold communicating with said exhaust entry port and having a pressure port leading outside said manifold; cooling air directing surfaces on said manifold associated with said end plates of said housing to direct cooling air thereto; a shroud around said housing and having an air entry port; and a blower means mounted on at least one of said end shafts adjacent said shroud, air entry port, whereby said blower means propels air to enable said shroud and air directing surfaces to direct cooling air to said end plates and propels air to said manifold lower inlet.

Pfeiffer 2302l0 Berges 2302l1 Houghton 230210 Ahlen et a1 230-2l1 X Lindhagen et al 230-2 ll X Petersen 2 30152 Hockel et al; 230-210 Briscoe 230152 Blackman 230-211 X FOREIGN PATENTS LAURENCE'V. EFNER, Primary Examiner. ROBERT M. WALKER, Examiner.

Claims

1. A ROTARY COMPRESSING PUMP COMPRESSING: A HOUSING INCLUDING END WALLS; A ROTATABLE ROTOR MEANS WITHIN SAID HOUSING; SAID PUMP HAVING A LOW COMPRESSION PUMPING ZONE AND A HIGH COMPRESSION PUMPING ZONE; A PLURALITY OF TRANSVERSE COOLING FINS AND INTERMEDIATE SPACES ON THE HOUSING EXTERIOR; A SHROUD GENERALLY AROUND SAID HOUSING AND INCLUDING COOLING AIR INLET AND OUTLET MEANS, AND SAID SHROUD AND FINS BEING RELATIVELY SPACED FROM EACH OTHER ADJACENT SAID LOW COMPRESSION ZONE TO ALLOW AIR TO PASS FROM SAID SHROUD INLET TO THE SPACES BETWEEN SAID FINS; SAID SHROUD AND FINS BEING CLOSELY POSITIONED WITH RESPECT TO EACH OTHER ADJACENT SAID HIGH COMPRESSION ZONE TO CAUSE SAID SPACES TO FORM SUBSTANTIALLY CLOSED PASSAGEWAYS WHEREBY AIR CAN BE UNIFORMLY DIRECTED OVER THE HEATED HIGH COMPRESSION AREA FOR EFFECTIVE COOLING; AND COOLING FAN MEANS ADAPTED TO PROPEL AIR OVER SAID FINS WITHIN SAID SHROUD.