US2496676A

US2496676A - Vacuum pump

Info

Publication number: US2496676A
Application number: US709328A
Authority: US
Inventors: Rawson Emanuel
Original assignee: RITE WAY PRODUCTS Co
Current assignee: RITE WAY PRODUCTS Co; RITE-WAY PRODUCTS Co
Priority date: 1946-11-12
Filing date: 1946-11-12
Publication date: 1950-02-07
Anticipated expiration: 1967-02-07

Description

E. RAWSON Feb. 7, 1950 VACUUM PUMP Filed Nov. 12', 1946 Patented Feb. 7, 1950 s PATENT oFFlcE VACUUM PUMP Emanuel-Rawson, Chicago, Ill., asslgnor to Rite- Way Products Company, Chicago, Ill., a corporation of Delaware Application November 12, 1946, Serial No. 709.328 8 Claims. (Cl. 230-207) This invention relates to pumps for pumping acter have heretofore been provided with an external muffler on the discharge side of the pump which muilier functions also to remove the oil particles that are carried by the air stream and permit the separated oil to flow back into the pump casing where it is picked up and recirculated to the moving parts of the pump. Such an external muffler not only increases the cost of the pump unit but also is` objectionable in that it constitutes a projection that extends from ythe ypump caslngand .is easily damaged. It is one of the objects of the present invention to provide a pump of the abovev mentioned character wherein the pump casing contains not only the pumping mechanism but also the muilier and oil separator and the oil circulating means.

It is a further object of the present invention to provide a pump casing which is so constructed Referring specifically to the drawings in'which i like numerals are used to designate like parts, I indicates a cast metal pump casing with cooling fins 2 on the exterior surface. is opengat opposite sides at one end thereof, the open sides being closed by a pair' of plates bolted thereto, as may be seen from Figures 1, 3 and 4. The interior of the casing has a web or partition 3 cast as an integral part of the casing, which partition divides ythe casing into an inlet compartment 4 in communication with a chamber in which a. rotor member is mounted, as hereinafter described, which rotor chamber communicates with

successive discharge compartments

4a, 4b and 4c, and thence to the pump outlet, as will be more fully described hereinafter.

The

compartments

4a, 4b and 4c are in effect one continuous discharge chamber which direct the educated air along a tortuous path. rThe .parti-v tion 3 includes a -horizontarwall portion 3a, an upper wall portionb and a Alower vertical Iwall v portion 3c that has an opening 3d therethrough.

that it-may be madeas a Vsimple casting the interior of which has integrally cast partitions which provide a space for the combination muffier and oil separator.

It is a still further object of the present invention to provide a dividing partition integrally cast with the rest of a pump casing, which partition not only forms the muffler compartment .but also forms a web for guiding the movable pumping mechanism, which web is so arranged in relation to the flow of lubricating oil as to facilitate lubrication of the movable parts carried by the Web.

The attainment of the above and further objects of the present invention will be apparent from the following specification taken in conjunction with the accompanying drawing forming a part thereof. I In the drawing: Figure 1 is a plan view of a pump embodying the invention;

Figure 2 is a longitudinal cross sectional view, taken along the line 2--2 of Figure 1;

. Figure 3 is a right end view of the pump of Figure l; and

Figure 4 is a fragmentary sectional view taken along the line 4 4 of Figure 2.y

The inlet compartment 4 has an inletcpening into which is threaded a combination check valve and connecting nipple 5, having external screw threads 6 on its wall for connection to a system to be evacuated. The check valve includes a ball 1 located within the nipple and normally rests in open position on a rod 8 away from avalve seat 9. When the pump is initially stopped air will tend to flow in a reverse direction through the pump into the vacuum line connected to the nipple 5. The ball I will then be lifted to its seat 9 to close the valve to prevent such reverse ow of air through the pump since such reverse flow might tend to operate the pump in the reverse direction. Under normal operating on nonoperating conditions the ball is in the ,position shown.

An eccentric or cam I0 is part of a rotatable drive shaft II and actuates a drum-shaped rotor I3. A counterweight I2 is secured to the shaft Il by a nut I4 and a lock nut I4'. A ball bearing is located between the eccentric and the rotor, this bearing comprising conventional respective inner and outer raceways I5 and I5 with balls I6 interposed therebetween.

' The rotating eccentric Il! moves the drumshaped rotor member I3 in an orbital path with one point of its periphery always in contact with a cylindrical wall Il forming the rotoror pumping chamber.

. A blade I8, flanged at one end to provide a foot I9 for attachment to the rotor member by screws I9a, extends through a slot 20 in the chamber Wall l1 and slides in a space 2l between The casing 3 two bearing members 22 which are free to oscillate in a socket 23 of the web or partition 3. Radial ducts 24 may be provided in the bearings 22 to facilitate lubricating oil flow between the contacting surface of the parts I8, 22 and 23.

The back end of the blade I8 moves in a chamber 26 within the web or partition 3. An opening 21 for reception of the blade I8 is sufiiciently oversized to provide clearance for the orbital movement of the blade I8.

A duct 28 in the partition 3 permits the flow of lubricating oil into the chamber 28.

The discharge compartment lc is provided with a connection 29, such as an elbow, for connection to an exhaust line or for directing the exhaust directly into the atmosphere. A muiiier 30, which also acts as an oil trap or lter, is located in the chamber 4c which is formed by the web or partition 3 within the casing. The muiller comprises any material suitable for separating oil from the ilowing air stream and may comprise a mass of hair, or steel wool, by way of example, which is held in the chamber 4c by a wire screen strainer 32. A top strainer screen 33 retains the filter material against being blown out by the moving air. The oil which is separated from the air in the muiiler ows back into the discharge compartment 4b.

A magnet 34 beneath the lter attracts any` free particles of iron that may reach the chamber 4b and thus prevents the circulation of such particles with the circulating lubricating oil. The magnet is on the end of a plug which is screw threaded into a threaded opening in the pump casing. The opening also acts as a drain opening upon removal of the magnet plug. For convenience in casting the pump casing an opening may be provided for supporting the core, which opening is then closed by a threaded plug 35 that lls the opening. 1

An oil recirculating tube 31 is mounted on and extends through the partition 3. The bottom of the tube is near thebottom of the compartment Ib. The opposite end of the tube has a plug 38 which supports the tube and is in turn thread.

ed into a tapped opening in the partition 3. The

plug 38 has a needle-like bore 33 therein which restricts the rate of oil tlow therethrough. Oil forced through the tube is ejected as a spray against the underside of a transparent inverted cup 40 the bottom of which ts into a bore 4I in the casing. The cup is detachably held on the casing inany desired manner, as by a snap spring clip 42. The inspection cup may be removed to replenish the oil supply. The angle and location of the bore through which the tube 31 extends is such that it is accessible for machining operations by insertion of a tool through the opening for the cup I0.

In operation of the pump the shaft Ii rotates counterclockwise as seen in Figure 2, causing the rotor I3 to move in a circular pathconstantly in contact with the cylinder bore I1. The blade I3 makes a sliding seal at the bearing members 22 and together with the rotor I3 and the partition 3 separates the inlet compartment 4 from the outlet compartments. 'I'he rotor action draws air from the intake and forces it through the

discharge compartments

4a, 4b and 4c and out to the atmosphere through the muiller exhaust 23. The air moving through the rotor compartment draws with it some of the lubricating oil within the pump. The quantity of lubricating oil initially placed within the casing is sumciently large so that the oil carried by the air moves through the compartment la as a thick mist. This mist is collected in the mumer and drains back into the compartment 4b. At the same time the preponderance o! pressure in the compartment 4b over the pressure in the vacuum compartment l forces oil to flow up the tube 31 and through the choke 3! where it is emitted as a stream of oil which impinges upon the sight glass or cup 4I and then drops down on the top of the web or partition 3. Some of the oil then nows through the duct 23 into the chamber 28 and is effective to lubricate the opposite surfaces o! the blade I3 and also to lubricate the contacting surfaces between the bearing 22 and the web or partition 3. The rest oi' the oil drops onto the top of the blade Il where it is picked up by the air stream and serves to lubricate the outer surface of the rotor I3 and the cylindrical wall I1.

As the air which carries with it the oil mist is educted through the pumping chamber it iirst passes through the restricted slot 20 and enters the large discharge compartment la. There its velocity is considerably reduced over the velocity of the air initially leaving the pumping chamber, due to the larger cross sectional area oi' the compartment 4a. The air traveling through the compartment 4a leaves that compartment via the small opening 3d in the wall portion 3c. In the compartment 4b the velocity of the air again changes over what it was through the restricted throat portion or opening 3d. The existence of the wall 3c with the opening 3d therein dividing the space into compartments 4a and lb serves to muiiie the noises of the air educted through the pump. The wall 3c produces changes in the direction o! the nowing air and thus tends to cause some of the oil that is carried by the moving mass of air to precipitate out. Likewise the air flowing from the compartment Ib to the compartment 4c has a substantial change in direction which further tends to separate out oil particles from the air stream. Furthermore, oil that is separated from the air stream as the air stream moves through the munier or iilter material 3l flows downwardly through the strainer 32 with the direction of the downward oil iiow at a substantial angle to the direction of the air ilow into and below the strainer 32. Therefore air moving upwardly through the strainer has a smaller tendency to inhibit the downward flow of separated oil through the strainer than would be the case if the air and oil were moving in exactly opposite directions.

From the above description it is apparent that 55 by the present invention there is provided a vacuum pump having a contained lubricating system and a contained munier and oil trap. By locating the muiller within the pump casing the applicant not only eliminates the expense of an external 30 muffler, but also eliminates the likelihood of damage to an externally extending muiiier. The applicant also eliminates thereby the possibility of air leakage to the atmosphere from the joints between the mufiier and the pump casing. such as e was present in the external muillers.

In compliance with the requirements oi the patent statutes I have here shown and described a preferred embodiment of my invention. It is, 70 however, to be understood that the invention is not limited to the precise construction here shown, the same being merely illustrative of the principles of the invention. What I consider new and desire to secure by Letters Patent is:

p 1. A gas pump comprising a casing having inprior vacuum pumps having i of the casing adjacent to and in line with the end of the tube which is in the inlet compartment.

2. A gas iiow device including a casing having means forming a pumping chamber at one end thereof, mechanically operable gas flow means in said chamber, a partition within the casing and constituting an integral part of the casing and together with the gas ow means dividing the casing into an intake compartment and a discharge compartment both communicating with the pumping chamber, an open ended lubrication tube extending through the partition to adjacent the bottom of the discharge compartment and establishing communication between the intake and discharge compartments for supplying lubricant for said mechanical gas flow means, said partment both communicating with the pumping chamber, the casing having a sight glass opening at the intake compartment thereof, a sight glass closing said opening, an open ended lubrication casing having an opening above the top of the tube, a closure for the opening, the tube directing flowing oil against said closure, said integral partition further subdividing the discharge compartment to provide a mufiier chamber at the outlet end of the discharge'compartment, the discharge compartment havin'gfin addition a baille wall 1 across the same forming va.' 'constriction therein to increase the'muiiling and oil separating action as an oil and gas mixture moves through the discharge chamber, said baille being an integral part of the casing.

3. A gas flow device including a casing having means forming a pumping chamber at one end thereof, mechanically operable gas iiow means in said chamber, a partition within the casing and constituting an integral part of the casing and together with the gas flow means dividing the casing into an intake compartment and a discharge compartment both communicating with the pumping chamber, the casing having sight glass opening at the intake compartment thereof, a sight glass closing said opening, a lubrication tube extending through the partition and establishing communication between the intake and discharge compartments, the tube being in line with the sight glass opening so that it is insertable into and removable from' position by a movement through the opening and directs the iiuid flowing therethrough towards the sight glass and into the gas stream in the intake compartment for lubricating said mechanical gas flow means, said integral partition further subdividing the discharge compartment to provide a mumer chamber at the outlet end of the discharge compartment, the discharge compartment having in addition a baffle wall across the same forming e constriction therein to increase the muiliing and oil separating action as an oil and gas mixture moves through the discharge chamber, said baille being an integral part of the casing.-

4. An air pump including a casing having means forming a pumping chamber at one end thereof, rotary air pumping means in said chamber, a partition within the casing and constituting an integral part of the casing and together with the pumping means dividing the casing into an intake compartment and a discharge comtube extending through the partition to adjacent the bottom of the discharge compartment and establishing communication between the intake and discharge compartments, the tube being in line with the sight glass opening so that it is insertable into and removable from position by a movement through the opening and directs the fluid owing therethrough towards the sight glass and into the gas stream in the yintake compartment for lubricating said pumping means, said integral partition further subdividing the discharge compartment to provide a muffler chamber at an end of the discharge compartment, the discharge compartment having in addition a baille wall across the same forming a constriction therein to increase the muiiiing and oil separating action as an oil and air mixture moves through the discharge chamber, said b aiiie being an integral part of the casing. y

5. A gas iiow device including a casing having means forming a pumping chamber atl one end thereof, mechanically operable gas flow means in said chamber, a partition within the casing, said partition together with the gas flow means dividing the casing into an intake compartment and a discharge compartment both communicating with the pumping chamber, the casing having a sightgglass opening at the intake compartment thereof, a sight glass closing said opening, and a lubrication tube extending through the partition and establishing communication between the intake and discharge compartments, the tube discharging into the region of the sight glass opening.

6. A gas flow device including a casing having means forming a pumping chamber at one end thereof, mechanically operated gas flow means in said chamberfa partition within the casing, said partition together with the gas ow means dividing the casing into an intake compartment and a discharge compartment both communicating with the pumping chamber, the casing having a sight glass opening at the intake compartment thereof,` a sight glass closing said opening, a 1ubricating tube extending through the partition and establishing communication between the intake and the discharge compartments, the end of the tube being in the region of the sight glass opening andthe tube being insertable into and removable from position by a movement through the opening, said tube directing the lubricant flowing therethrough towards the sight glass opening, said lubricant then moving into the gas stream in the intake compartment for lubricating said mechanical gas now means.

EMANUEL RAWBON.

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