US2240356A - Fluid pressure pump - Google Patents

Description

April 29, 1941. G. H. TESSMER 2,240,356

FLUID PRESSURE PUMP Filed July 1, 1959 -Z33. U619 Zor 601 0 012 JZ 1 651112987 Patented Apr. 29, 1941 FLUID PRESSURE PUMP Gordon H. Tessmer, Minneapolis, Min-11., assignor to Warner Manufacturing Company, Minneapolis, Minn., a corporation of Minnesota Application July 1, .1939, Serial No. 282,562

1 Claim.

My invention provides an extremely simple and highly efficient fluid-pressure pump of the rotary or centrifugal type, having the various improved features of construction and operation hereinafter described and defined in the claim.

The improved pump is capable of being made in various diiferent sizes and put to various different uses, but has been especially designed and particularly adapted for use in centrifugal pumps driven by small electric motors. Selistarting electric motors, as is well known, have relatively low starting torques, and this is especially true in respect to small electric motors.

Leakage between the motor driven pump shaft and the pump casing has hitherto generally been prevented by packings which must engage the pump shaft with very considerable friction to prevent leakage. Thefriction of such packing has-hitherto made necessary the use of an electric motor of greater power than would be required after the motor has once been started.

A major feature of my invention is directed to the provision of a substitute for the ordinary packing, which, while efficient to prevent leakage, will ofi'er but very slight friction to the starting of the motor. This feature is met by the use of a sealing diaphragm through which the pump or motor shaft is passed into the pressure chamber of the pump. The sealing diaphragm and the co-operating contacting elements are of novel construction and arrangement as will presently appear. The various novel features of the invention will be made clear by the concrete illustration of a specific problem for which the invention has been designed and for which it has been commercially employed, and which device is illustrated in the accompanying drawing wherein like characters indicate like parts throughout the several views.

Referring to the drawing:

Fig. 1 is an elevation showing the improved pump and parts of an electric motor for driving the rotary element of the pump;

Fig. 2 is a section taken on the line 22 of Fig. 1 showing the parts on a larger scale than in Fig. 1;

Fig. 3 is a vertical section taken through the pump on the line 3--3 of Fig. 2; and

Fig. 4 is a perspective showing in detail the rotary element of the pump.

The pump casing, as shown, is made of two elements, to wit; 6 and I. The main pump element 6 is formed with a pressure chamber 8 with an intake passage 9 and with a discharge passage ill. The intake passage 9 will be assumed to be connected to a source .of liquid supply such as an elevated tank, not shown, by a pipe II. The outlet passage In is connected to an upright stack l2.

The section 1 is in the nature of a head detachably secured to the main section 6 by machine screws I3 or the like. This head I, in the structure illustrated, is bolted to or otherwise rigidly secured to the casing M of an electric motor having an extended armature shaft 15. The head 1 is formed with a large axial passage l6 which may be nearly or about as large as the pressure chamber 8.. i

A sealing diaphragm H is clampedat its outer edge, with a fluid tight joint, between the sections 6 and 1 and is formed with an axial passage 18 through which the armature shaft l5 projects into the pressure chamber 8. Within the pressure chamber 8 the armature shaft I5 is provided with a head which, as shown, is in the form of a cap-like sealing head l9 telescoped on to the same and rigidly secured thereto by a machine screw 20. The cap-like head is provided with a propelling blade 2| that may be variously formed but, as shown, is wrapped around and welded or otherwise rigidly secured to the cap with its blade projecting tangentially therefrom.

The numeral 22 indicates a packing clamped between the inner end of the shaft [5 and the end of the head Ill. The large or outer end of the head I9 acts as a sealing surface against the diaphragm and is in the plane that is perpendicular to the axis of the shaft and has direct frictional engagement with the inner portion of the diaphragm IT. The end of the caplike head I9 is yieldingly held in frictional contact with the diaphragm, by suitable means, such as a coil spring 23 compressed between the motor casing and a pressure washer 24 that directly engages the radially inner portion of the diaphragm.

To permit slight wobbling of the shaft IS in case that should occur, the axial perforation l8 of the diaphragm is made large enough to amply clear the shaft l5. To permit slight axial move ments of the armature shaft and parts carried thereby, if such movement should occur, the diaphragm I1 is made of at least slightly flexible material. The kind of material used in the diaphragm will depend a good deal upon the nature of the liquid that is being used in the pump and should be such as not to be chemically acted upon by such liquid.

In practice I have used this pump for the pumping of kerosene which requires a very tight joint to prevent leakage; and. for the purpose have made the diaphragm of material such as generally known as Dupreme but various other materials may be employed.

The tension of the spring of yielding element 23 should be such and only slightly in excess of that required to seal the joint between the diaphragm and the head of the shaft under the maximum pressure that can be produced by the action of the pump. This may be accomplished in several ways. For example, the propeller blade 2| should be of such size and clearance in the pressure chamber that no matter how fast it is rotated by the motor, it cannot produce sufiicient pressure to overcome the spring and produce a leaking joint.

For a further illustration of a specific use of the pump for pumping kerosene, a small selfstarting electric motor was employed in connection with the pump in which at maximum speed the pump would elevate the kerosene to a maximum of only twelve inches. Then in the column l2, the overflow or relief pipe 25 was at an elevation to permit overflow when the column of fluid reached an altitude of eight inches. The tension of the spring 23 was then set or the spring was so designed that it would keep the flexible diaphragm pressed against the head I9 under pressure of a column very slightly in excess of twelve inches. 7 7

With thisarrangement, under normal conditions, there would be maintained a column of flowing liquid at an altitude of eight inches, and even if the circulating pipe should be clogged, the diaphragm would not be unseated nor leakage produced. With this arrangement the friction between the head 19 and the diaphragm is reduced to the minimum and will not impede to any great extent the starting of the relatively small motor.

If the pump shaft should, because of wear or for lack of accurate adjustment, be capable of slight axial movement, that movement would be taken up by the resilience of elasticity of the diaphragm. If the shaft should wobble slightly, the sealing surface of the sealing head I9, in addition to rotating against the diaphragm, would simply slip eccentrically against the face of the diaphragm without producing any material increased friction. The arrangement described accomplishes all of the desirable results above indicated.

"peller and casing.

From the foregoing it follows that the preferred form of the device illustrated in the drawing is capable of various modifications within the scope of the invention herein described and claimed.

What I claim is:

A fluid pump of the circulator type comprising a casing having a cylindrical pressure chamber open at one end of said casing and being closed at its opposite end by an inwardly recessed casing wall, an inlet port leading axially into said chamber through the recess in said end wall, an outlet leading radially through said casing from the cylindrical wall of said chamber, a flexible diaphragm secured over the open end of said chamber and providinga flexible end wall therefor, a rotary shaft extending through said diaphragm and terminating within said chamber, a hub mounted on said shaft within said chamber and having a radially extending flange in frictional sealing engagement with the inner side of said diaphragm, a propeller of materially less dimensions than said pressure chamber mounted rounding said shaft and yieldably engaging the outer side of said diaphragm to maintain a fluid seal between said shaft and diaphragm under relative axial and lateral vibrations of said pro- GORDON H. TESSMER.

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