US1163778A - Centrifugal pump. - Google Patents

Description

W. P. SCHEURMANN.

CENTRIFUGAL PUMP.

APPLICATION men SEPT. 23. 1913.

1,163,778. Patented Dec.14,1915.

2 SHEETS-SHEET I.

RAIH C0,,WASHINGTON D W. P. SCHEURMANN.

CENTRIFUGAI. PUMP.

APPLICATION FILED SEPT. 23. I913.

1,163,778. Patented Dec. 14, 1915.

2 SHEETS-SHEET 2.

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' UNITED TATE PATENT WALTER P. SCHEURMANN, OF DAYTON, OHIO.

CENTRIFUGAL PUMP.

Application filed September 23, 1913.

7 of its objects being to automatically create a counter thrust equal to any temporary influence tending to displace the impeller longitudinally.

Another object is to construct a centrifugal pump in such a way that, without thrust bearings or similar mechanical devices, any permanent thrust tending to displace the impeller, such, for example, as-gravity in a vertical pump, may be neutralized.

These objects are attained by a novel disposition of the water as it flows through the diifusion chamber on its way to the outlet, and one of the particularly valuable features of my invention is that the neutralization of end thrust does not involve any increase in the distance traversed by the water, nor is any part of the water diverted for the purpose. The water in the diffusion chamber is made to oppose any tendency on the part of the impeller to move longitudinally, but in doing so no energy is lost. The efficiency of the pump is therefore not affected by the part the ater plays in balancing end thrust on the impeller.

In the accompanying drawings Figure l is a section through a pump in which the water is taken into the impeller from both sides; Fig. 2 is a similar view of a pump in which the water enters at one side of the impeller only, and Fig. 3 is a similar view of a pump in which the impeller rotates on a vertical axis.

Similar numerals indicate similar parts in all of the views.

Referring now more particularly to Fig. 1, is an impeller and 11 the shaft on which it is mounted to rotate in bearings 12. As there are many forms of impellers, any one of which would be applicable to and useful in connection with my invention, no detailed description of the impeller is necessary other than to say that it has inlets 13 Specification of Letters Patent.

Patented Dec. 14;, 1915.

Serial No. 791,422.

for the water which is discharged in the usual way at let. The impeller rotates in a casing 15 having a diffusion chamber 16 which surrounds a .substantial part of the impeller.

The action of the pump is as follows: \Vater is conducted to the recesses 17 by a pipe or pipes (not shown in Fig. l) and enters the impeller at 13-13. The annular ridge 18 on the inside of the diffusion chamber cuts or di *ides the stream of water as it leaves the impeller, a portion of the water flowing into the space between the impeller and one side of the diffusion chamber, while the remainder flows into the space between the impeller and the other side of the chamber. In normal operation the impeller will rotate in a central position with reference to the ridge; 2'. 6., the ridge will be opposite the center of the outlet 14: of the impeller, in

which case an equal amount of water will flow into each side of the chamber and the pressure against the outsides of the impeller will be equal. Should the impeller be moved longitudinally by any cause the ridge will no longer divide the water equally, but more will be taken into one side and less into the other side of the chamber, thereby increasing the pressure against one side of the impeller and diminishing it against the other side. Obviously this will tend to restore the impeller to its former and balanced position.

The exact manner in which the equal or unequal division of the water in the diffusion chamber varies the pressure against the sides of the impeller depends upon the conditions under which the pump is operating. If, as may be the case, the chamber is not quite full. of water, the part of the chamber nearest the axis being empty, the balanced position will be attained when the submerged area of the sides of the impeller are equal. Under such conditions longitudinal displacement of the impeller will reduce the submerged area at one side and increase it at the other side of the impeller, thereby varying the relative pressure against the sides of the impeller proportionately. If, on the other hand, the diffusion chamber is full, the mere impact of the increased volume of water against one side of the impeller will tend to restore it to a neutral position. As movement of the impeller toward either side of the chamber reduces the capac- Cir ity of the space between the impeller and the side of the chamber toward which it has moved, while the quantity of water directed to that side is increased, it is obvious that the velocity of the water must increase on the side toward which the impeller has moved, while there is a reciprocal reduction in the velocity of the water on the other side of the impeller. And since velocity is converted into pressure in the diffusion chamber of a centrifugal pump, it follows that the pressure is increased on the side of the chamber toward which the impeller has moved, while it is reduced on the other side. Moreover, as the increase in pressure on one side is due to two causes; namely, an in creased volume of water to be cared for by a passage of reduced capacity, while the reduction of pressure on the other side is due to a reciprocal inversion of these causes, it follows that a comparatively slight longitudinal movement of the impeller will result in a very considerable difference in the relative pressure against the sides of the im peller.

The foregoing is based upon the supposition that there is no permanent influence tending to displace the impeller longitudinally. In a case where there is a constant tendency to displace the impeller longitudinally; for example, where the water enters the impeller at one side only as in Fig. 2, or where gravity is a factor, as in the vertical pump shown in F 3, the normal position of the impeller with reference to the ridge 18 will be such as to produce a preponderance of pressure against one side of the iumel er equal to the force tending to displace it.

Balancing the thrust of the impeller shaft with water flowing through the pump not only eliminates the necessity for thrust bearings, thereby reducing the cost of construction, but, because of the reduction of friction, increases the efficiency of the pump. Some attempts have been made by others to do this, but, so far as I am aware, all such have involved diversion of a portion of the water, obviously reducing, at least varying, the eiiiciency of the pump. In my pump, however, there is no diversion of the water; it is merely divided temporarily, the division being proportional to the force tending to displace the impeller. This tempo-- rary division of the water neither affects its pressure at the outlet nor reduces its volume. That being true the volume of water discharged from the pump will not be affected by the position of the impeller with reference to the stationary parts of the pump.

In Fig. 2 the casing is made in two parts,

with the ridge 18 a, relatively thin plate clamped between them.

Other modifications may be made without departing from the substance or exceeding the scope of my claims, which are as follows:

1. In a centrifugal pump, the combination of an impeller, a casing having a diffusion chamber surrounding the periphery and sides of the impeller, through. which the water discharged from the impeller flows, and means whereby when the impeller moves longitudinally the area of the impeller submerged is increased on the side toward which the impeller has moved, while the submer ed area on the other side of the impeller is proportionately diminished.

2. In a centrifugal pump, the combination of an impeller, a casing having a diffu sion chamber surrounding the periphery and sides of the impeller, said chamber having an outlet through which water is discharged, and means for temporarily dividing the water after it leaves the impeller, part of it flowing between one side of the impeller and the casing and part of it flowing between the other side of the impeller and the casing, the proportions of the division being governed by the position of the impeller relative to the stationary parts of the pump.

3. In a centrifugal pump, the combination of an impeller, a casing having a diffusion chamber with an outlet, said chamber surrounding the impeller to such extent that its sides are submerged by water flowing through the chamber to the outlet, and means which causes the relative pressure of 'ater against the sides of the impeller to vary according to the longitudinal position of the impeller with reference to the stationary parts of the pump.

4:. In a centrifugal pump, the combination of an impeller, a casing having a diffusion chamber with an outlet, said chamber surrounding the impeller to such extent that its sides are submerged by water flowing through the chamber to the outlet, and means for causing the relative quantity of the water flowing between the impeller and the sides of the chamber to'vary according to the longitudinal position of the impeller with reference to the stationary parts of the pump.

In testimony whereof I signature in the presence of two subscribing witnesses.

F. K. FAssiirT, C. H. KRUGER.

P. SCHEURMANN.

Copies oi this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

' Washington, D. C.

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