US2580347A - Centrifugal pump - Google Patents

Description

Dec. 25, 1951 G. K. EGGLESTON CENTRIFUGAL PUMP Filed Oct. 29, 1946 n INV roza. M/r. a

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Patented Dec. 25, 1951 2,580,347 CENTRIFUGAL PUMP Gilbert K. Eggleston, Mansfield, Ohio, assig'nor to Barnes Manufacturing Company, Mansfield, Ohio, a corporation of Ohio Application October 29, 1946, Serial No. 706,477

1 Claim.

My invention relates to self-priming centrifugal pumps and more particularly to centrifugal pumps of the suction lift type, in which the inlet to the pump rotor or impeller chamber is substantially coaxial therewith.

An object of the present invention is to provide self-priming means which is substantially anticlogging, that is, which is so located with respect to the periphery of the impeller and the liquid chamber of the pump that foreign matter drawn in with the liquid into the impeller chamber will have unobstructed and free access to the liquid discharge or air separating chamber and will be prevented from stopping or clogging the priming opening to the impeller chamber.

Another object of the invention is simplicity in construction and efficient operation under all conditions of operation, including heavy duty service.

A further object of the invention resides lin the provision of a pump of the above named character which is automatically self priming in use, the priming function being automatically effective in starting and ineffective when the pump is primed and pumping liquid.

Other objects f of the invention will become more apparent from the following description of several embodiments thereof, reference being made to the accompanying drawings in which like reference characters are employed to designate like parts throughout the same.

In the drawings:

Figure 1 is a vertical section through a pump embodying one form of the invention a taken on line I-I of Figure 2,

Figure 2 is a sectional view taken on line II-II of Figure 1, and,

Figure 3 is a fragmentary section of a lower part of the impeller chamber wall illustrating a modified form of my invention in which the priming opening opens downwardly and radially of the impeller chamber and communicates with the liquid and air separating chamber therebeneath.

In carrying out my invention, I have overcome and eliminated one of the most objectionable faults of self priming'pumps, that i the fault of clogging or stoppage of the priming opening by foreign matter drawn into the pump at its inlet and then into the impeller chamber. Some of such material will, of course, seek an exit through kthe priming opening or port during the priming cycle while some will pass along the volute and into the liquid chamber.

Referring rst to Figures l and 2 in which I have illustrated a pump embodying one form of the invention, the pump casing is shown at I, there being an intake opening at 2 and a delivery opening at 3. The casing is preferably cast in one piece, as shown, and comprises an intake chamber 4 communicating with the intake opening 2 and the volute or impeller chamber 5, and liquid chamber 6 communicating with the outiet s.

The impeller chamber or volute B is separated from the liquid chamber Ii by means of the wall 1 of the intake chamber and a wall 8 which extends radially outwardly of the intake chamber wall to merge with the wall 9 of the volute and forming with the casing wall I0 the lower portion II of the liquid chamber 6. As shown in Figure 1, the volute 5 opens at I2 directly into the chamber 6 in the lower region of the casing which also serves as an air separation chamber.

An impeller I3 is mounted to rotate in the impeller chamber 5, its rotating axis and that of the inlet opening I4 being in substantial alignment. This impeller comprises a body or back plate I5 having a plurality of curved blades I6 arranged on its forward face in spiral-like fashion and preferably formed integral with the impeller body I5. These blades are curved from the periphery toward the axis of the impeller and may overlap each other in spaced relation as shown in Figure 2, the outer ends of the blades sweeping close to the free end or cutoff I1 of the volute wall I8. As shown in this figure, the impeller is driven to rotate in a clockwise direction. The impeller is mounted on. and rotates with, the driven shaft I9 which, in the present instance, is a continuation of the shaft of a prime mover 20. The projecting end of the shaft carrying the impeller is carried in the boss 2|, there being a suitable lubricant packing 22.

Drain or cleaning plugs may be provided at 23 and 24 for the chambers II' and 25 respec-` tively. y

The intake 2 is provided with a check valve 26 seating on the seal 26 to close the opening 2 against back iiow f'. im the pump.

In the embodiment of my invention shown in Figures l and 2 the priming opening is formed in the lower region of the wall 8 at the periphery of the impeller I3 opening downwardly as shown in VFigure 2 to afford lateral communication between the volute or impeller chamber 5 adjacent the tips of the blades and the air separation chamber 28,

The operation of this embodiment of my invention may be described as follows.

The pump body is iirst filled with the liquid to be pumped. This may be done by supplying the same through the opening 3 or the pump may be 'filled from prior operation. Since the check valve 26 normally seats on the seat 26', the intake opening 2 is closed when the pump 'is not in operation, preventing a back flow of liquid out of the pump body through this opening. When the impeller I3 is rotated or driven by the power source 20 it rapidly comes up to rotation at high velocity in a clockwise direction as in Figure 2.

The liquid in the volute 5 and between the impeller blades is first expelled outwardly by centrifugal force moving around the volute and discharging into the separation chamber 28. Such action causes the liquid in the inlet chamber to flow or be drawn axially toward the impeller, simultaneously causing the valve E6 to open to the volute.

permit liquid to. be pumped to a higher level to be drawn into and through the inlet 2. This liquid by continued rotation of the impeller at high velocity is drawn between the whirling impeller blades I6 and is likewise expelled outwardly into the volute by centrifugal force. The column of liquid is thus brought into increasingly rapid rotation around the volute and into separation chamber 28 causing the liquid in the liquid chamber Il to rise in the pump body and pass out the discharge opening 3 to which a hose or pipe (not shown) may be connected.

As liquid is expelled from the-inlet chamber I, air from a suction pipe or hose connected with the inlet 2 together with liquid to be pumped will be drawn into the pump body and into the impeller chamber or volute 5 passing rst between the impeller blades I6 and then outwardly between the blades by centrifugal force. Rapid rotation of the blades tends to beat or break up the air in the liquid body within the impeller chamber and causes the air to be enveloped in the liquid in the form of bubbles. This aerated liquid is carried off and out of the volute discharge I2 into the separation chamber 28. At the same time liquid in the chamber II will flow into the impeller chamber 5 through the elongated opening 21 formed in the wall 8 and extending from the free end I1 of the volute wall in a direction counter to the direction of rotation of the irnpeller as shown in` Figure 2. This liquid and some of the aerated liquid in the separation chamber 28 ows in a direction facing the rotational field of the impeller and isdrawn between the rotating impeller blades and is again driven off into In its travel, this liquid may pick up and entrap additional air entering the impeller chamber through inlet I4 and so promotes further aeration of the liquid by entrapping the air therein. In this manner the liquid is recir- 'culated from the volute mouth through the separation chamber, laterally through the opening 21 opposite the tips of the blades I6 and into the volute. This recirculation of the liquid and entrapped air will continue until all of the air has been exhausted from the suction pipe and the inlet chamber l 'and is forced upwardly in the liquid chamber II and the upper chamber 6 and out through the outlet 3.

The liquid in the volute is kept in a continuous state of rapid rotational movement therein, there being no point in the volute where air can be entrapped so as to prevent eflicient operation of the pump or its self-priming action.

AWhen all the air has been evacuated from the volute, suction is established to the intake opening and the valve thus drawing up liquid into the pump and axially into the impeller. The rapidly rotating impeller throws off the liquid peripherally into the volute channel in rapid movement past the opening 21 which cuts ofi or arrests the flow of liquid through this opening from the separation chamber to the impeller chamber thus stopping recirculation. Under such conditions the pump will function as a standard centrifugal pump. that is, the liquid discharged from the mouth of the volute into the chamber 28 will be forced up through the chamthese conditions, there will be no recirculation of the liquid through the opening 21 as explained above, but if the pump loses its prime recirculation is restored until the pump has reprimed itself.

In order to prevent syphoning or loss of liquid when the pump is stopped, the check valve 26 will close on its seat to prevent the escape of any liquid past the inlet opening from the chamber 4.

I have found that by locating the opening 21 so that one end is contiguous with the cutoff I1 so that the opening lies along the periphery of the impeller, the tendency of foreign matter drawn in with the liquid through the inlet to clog or obstruct the priming opening 21 is reduced and generally eliminated. This undoubtedly is due to the form of the opening 21, which as illustrated, results from interrupting the periphery of wall 8 at a point contiguous with the cutol I1 in the form of an arcuate slot opening downwardly into the chamber 28 and laterally into the volute 5. As such, there is no restricted passage in which foreign matter may lodge or build up to the extent that recirculation, when desired, becomes impaired.

In Figure 3 I have illustrated a modied form of the invention in which the priming opening 50 is shown as a slot communicating the impeller chamber 5 with the separation chamber 28. The slot is formed in the bottom wall of the volute and opens downwardly radially of the impeller chamber. The opening 50 is elongated and, like the form shownv in Figures 1 and 2, is located so that one end thereof is contiguous with the cutoff I1.

Various changes may be made in the details of construction and arrangement of parts without departing from the spirit of the invention or the scope of the appended claim.

I claim:

A self-priming centrifugal pump comprising a pump casing having a liquid separation chamber and an impeller chamber of volute form separated by a wall therebetween, said wall having a peripheral portion and a radial portion with respect to the rotational axis of an impeller in said impeller chamber, an impeller rotatable in the impeller chamber, a liquid inlet passage through said liquid separation chamber and communicating with said impeller chamber, the peripheral and radial portions of said wall extending at one end from a point dening a blade cut-oil', said peripheral wall terminating at its other end at a point spaced from said blade cut-off, the radial portion of said wall between said cut-off and said cther end of said peripheral wall being relieved radially inwardly thereof to form a priming opening directed radially downwardly in the plane of the radial wall and communicating said im'- peller chamber directly with the separation c'hamber.

GILBERT K. EGGLESTON.

REFERENCES CITED The following references are of record in they le oi this patent:

` UNITED STATES PATENTS

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