Screw-pump.

Application filed August 28,1908, Serial No. 450,707. Renewed July 21, 1909. Serial No. 508,785.

the cylinder head. The screw blades are so arranged that one is acting in connection with one of the inlet openings, while the other screw blade is simultaneously acting in connection with the other-inlet opening, 6C both blades working close against the inner face of the head cf the cylinder and serving to force the water longitudinally of the cylinder to the discharge end. Tlie discharge openings in the cylinder head, together with 65 the outlet pipe from the casing are counterparts of the arc-shaped inlet openings 10 / and 11 and the inlet 6,. ' ,

In order to prevent the back drag of the ' water which results from the skin friction 7 0 . existing between the surface of the screw blade and the body of water, I provide means whereby the body of water having been forced longitudinally of the cylinder will be separated from the screw blade which 75 has propelled it so that it will be relieved of the skin friction’ and may be acted on anew by a second blade forming in effect a continuation of the first blade section. These means consist of a diaphragm 12' se- 80 cured to the cylinder of the pump and extending transversely across the same, it having a central opening for the passage of the . shaft and having a plurality of openings 12 and 13, the aggregated area of which is ap- 85 proximately equal to the aggregated area of the inlet openings 10 and 11 or of the discharge openings leading from the pump. This diaphragm or diaphragms may be secured in place in any suitable manner. I 90 have shown, however, screws at 14, passing through the casing into the said diaphragm. It will be seen from Fig. 1 that each of the screw blades 4—5 works closely against both the inner surface of the head of the cylinder 95 and against the face of the diaphragm 12' so that in the revolution of the screw the blades will cut off the water at the inlet openings and press this cutoff portion forward through the openings in the diaphragm, and 100 immediately upon its passage through the diaphragm the*effect of skin friction will be eliminated and the body of water which has just passed through the diaphragm will be subjected to the action of the next section of 105 screw blades and so on throughout the cylinder.

It will be noticed from Fig. 1 that the sections of the blade 4 form in effect a contin- / nous screw from end to end of the cylinder, 110

To aU whom it may concern:

Be it known that I. Ebastus S. Bennett, a citizen of the United States, residing at New York, N. Y., have invented certain 5 new and useful Improvements in ScrewPumps, of which the following as a specification.

My invention relates to screw pumps of the general form disclosed in an applica10 tion for Letters Patent of the United States filed by me April 6, 1908, No. 425502. In said application I disclose a pump comprising a cylinder having a plurality of inlet openings in one of its headstand a plurality 15 of outlet openings in the other head, a screw within the cylinder having a plurality of threads which, are displaced circumferentially in respect to each other, one thread acting in connection with one inlet and out20 let, while simultaneously the other thread acts in connection with the other inlet and outlet, the ends of the screw threads working close against the said heads..

My present invention includes in connec25 tion with the above features means within the cylinder of the pump for eliminating the effects of skin friction of the blades upon the body of water to be forced, said means consisting of . a diaphragm or diaphragms so which are interposed in the screw blades, the said diaphragms having openings of an aggregated area, approximating to the area of the inlet or outlet opening of the cylinder.

The invention is disclosed in the accom35 panying drawing, in which,—

Figure 1 is a vertical sectional view taken longitudinally through the pump. Fig. 2 . is a vertical sectional view taken transversely through the pump on the line 2—2. 40 Fig. 3 is a cross sectional view on the line 3—3 of Fig. 1. Fig. 4 is a face view of one of the inlet or outlet openings of the pump. Fig. 5 is a face view of one of the diaphragms.

In these 'drawings, 1, indicates the cylinder, 2, the shaft, turning in bearings 3 on the heads of the cylinders outside the same, and 4 and 5 indicate the screw blades carried by the said shaft and. working within 50 the cylinder. The inlet opening is. formed in a casing 6, formed or cast with the cylinder head, the said inlet having a web 7 extending across the same dividing’the inlet into two openings 8 and 9, which lead to 55 the arc shaped inlet openings 10 and 11 of

950,564 the diaphragms as it were occupying the space left by the cut out portions of the said screw blades, and .extending transversely of the axis of the blade. Any desired number 5 of diaphragms may be used..