US2321498A

US2321498A - Pump

Info

Publication number: US2321498A
Application number: US333527A
Authority: US
Inventors: Leo S Madlem
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-05-06
Filing date: 1940-05-06
Publication date: 1943-06-08
Anticipated expiration: 1960-06-08

Description

June 8, 1943. L. s. MADLEM PUMP Filed May 6, 1940 2 Sheets-Sheet 1 LEO S. MADLEM.

A TTORNEVS.

Juhe 8, 1943. s. MADLEM PUMP Filed May 6, 1940 2 Sheets-Sheet 2 r INVCNTOR, 1.50 s. MADLEM.

ATTORNEYS.

Patented June 8, 1943 PUMP Leo S. Madlem, San Francisco, Calif. Application May 6, 1940, Serial No. 333,527

2 Claims.

This invention relates to pumps of the positive displacement type, and has, among its objects, the provision of a rotary pump adapted for deep well use; to provide a pump of the rotary vane typewherein the vanes are positively driven by mechanical means, and are not required to be urged outwardly by resilient pressure; to provide a pump which may be relatively long in comparison with its diameter and may still be provided with ade-.

quate ports to discharge longitudinally without undue friction losses; to provide a pump of the rotary vane type wherein the particular vane or rotary piston which is momentarily acting the impeller turns in positive contact with the pump cylinder; to provide a pump of the type described which is sufficiently well sealed so that it will produce a vacuum of twenty-eight inches of mercury or over, and will operate sufficiently well on a combination of water, steam, and air, to nable it to be used as a wet vacuum pump; and to provide a pump having the characteristics described which can be cheaply and easily manufactured.

Other objects of my invention will be apparent or will be specifically pointed out in the description forming a part of this specification, but I do not limit myself to the embodiment of the invention herein described, as various forms may be adopted within the scope of the claims.

Referring to the drawings:

Fi l is a side elevation of a pump embodying my invention.

Fig. 2 is a vertical sectional view of the pump shown in Fig. l, the plane of section being indicated by the line 2-2 in the first figure.

Figs. 3 to 7 inclusive are transverse sectional views, the planes of section being the line in Fig. 2 carrying like numerals; and

Fig. 8 is a sectional view similar to Fig. 6 and showing a construction which may be utilized to increase the area of the port normally used for outlet.

Fig. 9 shows the outlet port in the form employed in connection with the modification of Fig. 8.

The nature of the invention may best be understood from a detailed description of the preferred form of the invention as shown in-the figures, which show a pump of the deep well type. As viewed externally the body I of the pump is preferably a cylindrical, cup-shaped casting, in the side of which are formed a plurality of small holes 3 which combine the functions of an intake port and a strainer. Secured to the top of the pump body by any convenient means such as the screws is a hollow cap 1, whose open end is interiorly threaded to receive a discharge pipe 9. For the sake of completeness, a discharge spout II is shown as connecting to the upperv end of the discharge pipe 9, which is closed by a bearing [3 for the drive-shaft l5 which transmits the necessary power for the pump, traversing the length of the discharge pipe and, preferably, terminating within the pumpbody I.

The lower end, of the shaft I5 is journaled in a pairof bearings within the pump body, one of these bearings being formed as a boss Il formed on the bottom of the pump body, and the other being a similar boss l9 which is carried on a cover plate 2| clamped between the body I and the cap 1. These bearings may either be plain bearings as shown or may be bushed in accordance with customary practice, the plain bearings being shown in the present instance in order to keep the drawings as simple as possible, it being understood that any suitable form may be used. The bosses l7 and I9 are made accurately cylindrical and coaxial, but are eccentric with respect to the shaft as shown in all of the transverse sectional views.

For a deep well pump it is convenient to make the pumping chamber 23 within the body I approximately circular and concentric with the outer surface. The exact contour of the greater part of the inner wall of thischamber is not particularly important; what is important is that the quadrant of this wall between the two points indicated by the reference characters 25 should be shaped so as to provide an accurate running fit with the mechanically driven vanes, as will later be described, and that there should be provided a land 21, projecting into the chamber opposite the quadrant just defined and having at least a portion of its inner surface also shaped to correspond with the motion of the vane tips. The intake ports 3 are all locatedon one side of the pump chamber between the

quadrant

25, 25, and one side of the land 21.

Keyed or otherwise secured to the shaft I5 is a rotor drum 29, which is secured to the shaft by a web 3|, preferably located medially between the ends of the pump chamber, and carrying -skirts 33 projecting above and below the central web for the full length of the cylinder to a bearing with the top and bottom thereof, the diameter of the cylinder being such that it makes a running fit against the land 21. Opposed slots 35, extending longitudinally of the drum, are equally spaced about the periphery thereof. Simplicity dictates that there should be four of these slots, corresponding with a four-vaned impeller, but it will be obvious that more could be used were it desirable for any reason to do so.

Pairs of

vanes

31 and 39 are fitted into the slot, and bear against the edges thereof. Plain metal-to-metal bearings between the vanes and the impeller drum give very satisfactory results, but I prefer to use insert strips 4! to reduce wear and friction, and for use in water these bearings strips may be made of rubber. Where the pump is to be used for oil, rubber is not satisfactory as the oil will attack it, and some of the synthetic oil resisting rubbers such as Neoprene, babbitt, or anti-friction bronzes or even hardened and polished steel may be substituted.

The

vanes

31 and 39 respectively of each pair are joined by a bridge 43, which carries at its center a scotch yoke 45 fitting over and driven by a respective one of the bosses i1 and is. It is preferable that this drive should be through a bushing 41, flattened on its two sides to bear upon the sliding faces 49 of the yoke, as this greatly lessens wear, but it is a refinement which may be omitted if desired, and the sides of the yoke may bear directly against the boss. It will be seen that the two pairs of

vanes

31 and 39 are identical, but that their positions are in verted with respect to each other, the bridge 43 of one pair being at the bottom of the cylinder so that the yoke engages the boss ll, while the bridge of the other pair is at the top (it the cylinder, and the yoke engages the boss I9.

It is obvious that rotation of the shaft will rotate the drum 33 and with it the

vanes

31 and 39. During this rotation the position of the vanes is at all times rigorously determined, in the plane of the vane by the bearing of the scotch yoke against the eccentric bosses, and at right angles to the plane of the vanes by the edges of the slots 35.

Owing to the rigorous positioning of the blades, their ends sweep out a perfectly definite path which is very nearly, though not exactly. circular. Its departure from circularity, particularly over the quadrant opposite to the cutoff land and that including the land itself, is of the order of one tenth of one per cent, or, say, six thousandths of an inch in a pump where the vanes are five inches from tip to tip. For

cheaply made pumps, where relatively large clearances are permissible, the interior of the pump chamber can therefore be machined in ordinary lathes with the centers at the center of the bosses, and the small variations in clearance as the pump rotates are unimportant. Because of the fact that the vanes are not in pressure contact with the walls of the cylinders at any time, such clearances are not increased by wear, and it has been proved'possible to pull vacua of over twenty-eight inches with five inch diameter pumps of this character, without any additional seals to compensate for the lack of circularity.

Where clearances of the order mentioned are important, however there are two readily effective methods of effect such a seal. The first. and in some ways the simpler, is to insert rubber sealing strips 5|, similar to the strips ll, in the ends of the blade, and such strips will readily compress sufllciently to accommodate 'for the varying clearance, and give a satisfactory seal at all times.

A more elegant solution, and one involving no approximations, is to machine the inside of the barrel in accordance with the vane edge path. This can readily be accomplished on an automatic non-circular lathe, and it may be done on an ordinary machine lathe by setting the cutting tool in a scotch yoke and duplicating in efiect the action of the vanes to machine out the cylinder.

It is possible, of course, to use the sealing strip ii in connection with such non-circular or quasi cardioid machining. The barrel 33 is of such diameter as to make a runningflt with the land 21. Again, the flt is not exact, but is so nearly so that its departure from exactitude cannot be shown in the drawings, and the seal which it provides is, in practice, entirely satisfactory.

Figure 8 show a modification of the invention in which the passageway 59 is formed behind the land 21', to permit of greater area in the exhaust passage 6| (see Fig. 9) where it is desirable to make the pump of small diameter and greater length, so as to increase capacity which may be satisfactorily utilized in a well of small diameter. Except for the feature mentioned, this device i entirely similar in principle to that already described, and further explanation is believed unnecessary.

I claim:

l. A positive pressure pump for vertical operation comprising an approximately cylindrical pump chamber having a top and bottom and a longitudinal cut-off land projecting into said chamber, circular bosses mounted on said top and bottom, midway between the top of said land and the opposite side of the chamber, the top of the land and the opposite side of said chamber having surfaces substantially concentric with said bosses, a drive shaft journaled eccentrically in said bosses substantially axially of said chamber and extending through said top, a drum having a plurality of opposed longitudinal slots therein extending the length of said chamber and secured to said shaft, and an impeller vane fitting into each of said slots, a bushing on each of said bosses, said bushing having wherein said vanes have flexible edges in engagement with the inner cylindrical wall of the pump chamber.

LEO S. MADLEM.