US2073733A - Priming means for centrifugal pumps - Google Patents

Description

March 16, 1937. E. F. DOTY PRIMING MEANS FOR CENTRIFUGAL PUMPS Fild May 26, 1934 Patented Mar. 16, 1937} UNITED STATES PATENT OFFICE 3 Claims.

This invention relates generally to pumps but more particularly to a priming means for centrifugal pumps.

It has for one of its objects to provide a device of this character which is simple, compact and inexpensive in construction, and which is so designed as to eifect the priming of the pump in a minimum period of time.

A further object of the invention is to provide an automatic priming device for centrifugal pumps which will in no way interfere with the normal operation of the pump and which has no valves or like parts liable to get out of order.

In'the accompanying drawing:-

Figure 1 is a cross section of a centrifugal pump showing my priming means associated therewith. Figure 2 is a longitudinal section taken on line 22, Figure 1.

Similar characters of reference indicate corresponding parts throughout the several views..

By way of example, my invention is shown in connection with a centrifugal pump of known construction, the numeral Ill indicating the pump-casing having a centrally arranged impeller chamber ll; l2 indicating suction chambers located at opposite sides of the latter in communication with the suction inlet H of the pump-casing; and I4 indicating pressure chambers disposed at opposite sides of the impeller chamber about said suction chambers and communicating substantially tangentially with the main discharge l5 of the pump-casing. Extending centrally through the impeller chamber and suction chambers, and journaled in suitable 3;, bearings I6 in the opposite sides of the. pumpcasing, is a horizontal driving shaft," on which the impeller I8 is fixedly mounted. While the impeller may be of any suitable construction, it is shown in the drawing as consisting of spaced 4o disks or shroud plates. l9 between which are disposed curved blades 20 suitably spaced to provide fluid passages opening outwardly and enlarging toward the periphery of the impeller in the manner shown in Figure 1 As seen in Figures 1 and 4;, 2, the impeller blades extend a suitable distance beyond the peripheral edges of the shroud plates to provide lateral discharge openings or ports 2| which communicate with the adjoining pressure chambers l4. Surrounding the impeller and dis- 50 posed in proximity to the outer edges of its blades- 20 is an impact face or rim 22 which functions to direct the liquid issuing from the impeller in ya lateral direction through the ports 2| into the pressure chambers l4.

55 The means for effecting the priming of the pump is associatedwith-the discharge side of the pump-casing It, being automatic or self-controlled, and preferably consists of an air-releasing chamber 23 disposed in a substantially upright position and connected to an elbow-like 6 extension or conduit 24 extending from the pump-casing and containing the main discharge l5 of the pump. A bridge wall 25 divides this conduit to provide the main discharge passage l5 which communicates with the pressure cham 10 upper end of -the chamber 23 has connected to it 20' a discharge pipe 28. It is desirable, in the event that a check valve is used in the discharge pipe and there is a head of water. above the valve when the pump is stopped or loses its suction prime, to place an automatic air release valve 29 25 in the top of the releasing chamber 23. However, should the pump be used with a free open' discharge pipe, then it is unnecessary to use the air release valve.

Before the first priming of the pump, it is 30 necessary to fill the pump casing ill with liquid to a level at least up to the bottom of the impeller eye in order to furnish the required amount of liquid for producing air entrainment. When the pump is then started up, the priming means comes into operation and there is discharged through the auxiliary passage 26 which is located in the plane of revolution of the impeller-blades 20, columns or pistons of liquid with entrained air, which liquid and air are thence discharged into the releasing chamber 23 where the air is separated from the liquid and passes ofi through the discharge pipe 28. The liquid utilized in the process of removing the air during the priming operation is recirculated back to the pump casing, this recirculation being caused by a slight difference in pressure between the point where the liquid and air isejected from the impeller chamber'into the auxiliary passage 26 and the point where the liquid is returned to the main discharge passage 15. When the pump is fully primed the liquid is discharged to a minimum the time required for priming under certain conditions, I provide a suction trap 30 which may be connected to the suction inlet 13 of the pump casing in the manner shown in Figure 1. This trap functions to maintain a high liquid level in the pump whenshut down or for any other reason which may cause it to lose its suction prime.

While I have shown a single auxiliary discharge passage 26, it is to be understood that any number of them may be employed, and where more than one is employed they may be centrally connected to a common passage which in turn is connected to the air-releasing chamber 23.

While my invention has been shown in connection with a centrifugal pump of the double-suction horizontal shaft type, it is to be understood that the same is applicable to single stage pumps of the single-suction type or to multistage pumps of either the single or double-suction type, or to vertical shaft pumps including any of the aforesaid types.

I claim as my invention:

1. A centrifugal pump, comprising a casinghaving an inlet and a discharge conduit, the latter having a bridge wall therein dividing the same into a main discharge and an auxiliary discharge, an impeller chamber in communication with said inlet and said auxiliary discharge, the latter being in the peripheral plane of said chamber and the main discharge being at one side thereof, an impeller open at its periphery and having lateral discharge openings rotatably mounted in said chamber, a pressure chamber arranged at one side of said impeller chamber and communicating with the same and with said main discharge, reactionary means surrounding the impeller cham her and in proximity to the periphery of the impeller for diverting the fluid through the discharge openings of the latter into said pressure chamber, the impact face of said reactionary means being substantially parallel to the axis of said impeller, and an air-releasing chamber connected to both the main and the auxiliary dis charge passages.

2. A centrifugal pump, comprising a casing having an inlet and a discharge, an impeller chamber in communication with said inlet, an impeller including blades, open at its periphery and rotatably mounted in said chamber, a pressure chamber arranged at one side of said impeller chamber and communicating with the same and with said discharge, the peripheral edges of the blades being parallel with and extending to the inner wall of the impeller chamber, said impeller having lateral discharge openings intersecting with the periphery thereof and communicating with said pressure chamber and said inner wall of the impeller chamber constituting an impact face for directing the fluid through said discharge openings at substantially right angles to the plane of rotation of the impeller, and an air chamber including a discharge conduit connected to said casing-discharge and having a bridge wall therein dividing the same into main and auxiliary discharges, the auxiliary discharge being connected to the impeller chamber in the plane of the revolving impeller-blades and the main discharge being connected to said pressure chamber.

3. A centrifugal pump, comprising a casing having an inlet and a discharge, an impeller chamber in communication withsaid inlet, an impeller includingblades, open at its periphery and rotatably mounted in said chamber, a pressure chamber arranged at one side of said impeller chamber and communicating with 'the same and with said discharge, the peripheral edges of the blades being parallel with and extending to the inner wall of the impeller chamber, said impeller having lateral discharge openings intersecting with the periphery thereof and communicating with said pressure chamber and said inner wall of the impeller chamber constituting, an impact face for directing the fluid through said discharge openings at substantially right angles to the plane of rotation of the impeller, and a discharge conduit connected at one end to said casing discharge and terminating at its other end in a substantially upright portion, said conduit having a bridge wall therein dividing the same into main and auxiliary discharges, the main discharge being connected to said pressure chamber and the auxiliary discharge being connected to the impeller chamber at the periphery of the impeller.

EDMUND F. DOTY.

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