US3474735A - Air dumping control mechanism for self-priming pumps - Google Patents

Description

Oct. 28, 1969 s. E. GILMORE 3,

AIR DUIPINC' CONTROL MECHANISM FOR SBLF-PRIMINC- PUMPS Filed May 24, 196.

2 Sheets-Sheet 2 United States Patent M 3,474 735 AIR DUMPING CONTR 0L MECHANISM FOR SELF-PRIMING PUMPS Samuel E. Gilmore, P.O. Box 265, Houston, Tex. 77001 Filed May 24, 1967, Ser. No. 640,971 Int. Cl. F04d 9/02 U.S. Cl. 103-113 3 Claims ABSTRACT OF THE DISCLOSURE Air escape mechanism for use with self-priming pumps which opens automatically to allow the bleeding oil? of air from the pump through the discharge outlet of the pump upon starting of the pump, and which closes automatically to prevent the outflow of liquid through the mechanism when the air has escaped.

The invention relates to self-priming pumps and more particularly to pumps used in the pumping of liquids from a lower to a higher elevation such as in the disposal of sewage.

In the disposal of sewage, especially in locations where the terrain is relatively flat, the sewer system is often constructed with pumping stations, disposed at suitably spaced intervals, at each of which the sewage is pumped from a lower level to a higher one and allowed to flow by gravity to the next station. Such stations may serve as collecting points for sewage which is drained from an extensive area into a sump or collecting basin and is then pumped into a tank or the like at a higher elevation from which it may flow by gravity to the next station.

The pumping of sewage in such a system is usually accomplished by self-priming pump of relatively large capacity which are started automatically when the level of liquid reaches a predetermined height in the collection receptacle and which are stopped automatically when the liquid level falls to a predetermined lower level. Due to the wide variation in the volume of liquid flowing into the system at diflerent times of the day, the pumps may operate continuously for substantial periods of time and at other times the pumps are out of operation.

Self-priming pumps of the kind usually employed in systems of this character are provided with air dumping outlets through which air may flow from a location somewhat downstream of the discharge outlet of the pump back to the sump, so that air may escape from the pump upon starting of the same, and when all of the air has been removed in this manner, liquid then flows continuously through the air dumping outlet back into the sump during the operation of the pumps.

In a system of this kind, the liquid being pumped often contain a great variety of debris, some of which may be of more or less solid character, in varying amounts, and due to the fact that the air dumping outlets are usually of relatively small diameter, they frequently become clogged, which results in failure of the system due to lack of prim ing of the pumps. Failures of this character may result in inconvenient shut downs in the system and the carrying out of costly emergency repair operations.

The use of air dumping outlets of greatly enlarged diameter in a system of this kind, to prevent stoppage 0f the outlets is unsatisfactory because of the large volume of liquid which is then returned to the sump which substantially reduces the efliciency of the system.

The present invention ha for an important object the provision of air dumping control mechanism for selfpriming pumps embodying means for preventing the clogging of the air dumping outlets during operation of the system.

Another object of the invention is to provide airdump- 3,474,735 Patented Oct. 28, 1969 ing control mechanism of the kind referred to including means for allowing the free outflow of air from the selfpriming pumps and which operates when the air has eseaped to close the mechanism against the outflow of liquid therethrough back into the sump.

A further object of the invention is the provision in a liquid pumping system of air dumping mechanism of the type mentioned wherein the air dumping outlet may be of greatly increased size to prevent clogging of the same by debris entrained in the liquid, and in which the mechanism functions to eliminate the loss of liquid being pumped due to backflow of the liquid through such outlet.

Briefly described the invention comprise mechanism having an outflow line for the outflow ofair from the discharge outlet of a self-priming pump, and including means for opening the outflow line for the outflow of air from the pump during the priming of the pump but which operates when all of the air has been removed to close the outflow line against the outflow of liquid therethrough during the pumping operation. The mechanism embodies an outflow line of relatively large capacity connected into the discharge line from the pump and including a flexible tube portion, diaphragm means which is operable under influence of the reduced pressure at the inlet of the pump to close the flexible tube portion when liquid is flowing through the discharge line from the pump, and mean responsive to the discontinuance of the reduced pressure at the pump inlet to allow the flexible tube portion to open.

The above objects and other obvious advantages of the invention may best be understood from the following detailed description, constituting a specification of the same, when considered with the annexed drawings, wherein:

FIGURE 1 is a fragmentary, side elevational view, partly broken away and partly in cross-section and on a reduced scale illustrating the invention and showing the same as applied to a sewage pumping system;

FIGURE 2 is a vertical, central cross-sectional view showing the control valve mechanism of the invention, the valve being shown in the position which it occupies during the outflow of air from the priming of the pump;

FIGURE 3 is a side elevational view, partly broken away and partly in cross-section of the diaphragm mechanism of the invention, the diaphragm being shown in the position which it occupies during the outflow of air from the pump; and

FIGURE 4 is a cross-sectional view, taken along the line 44 of FIGURE 3, looking in the direction indicated by the arrows.

Referring now to the drawings in greater detail, the air dumping control mechanism of the invention is illustrated herein in connection with its use in a sewage disposal system of a Well known type having a collecting basin or sump 10 into which sewage flows from a higher elevation, and from which an outlet pipe 12 leads to the inlet side of a self-priming pump 14 by which the sewage is pumped from the sump to a higher elevation, through a discharge line 16, to flow by gravity to a disposal point at a distance. In sewage disposal systems of this kind the quantity of sewage which flows into the sump may vary widely at different times of the day, so that the pump may be in operation for varying periods and means is provided for automatically starting and stopping the pump in a manner to take careof the varying load requirements of the system.

The outlet pipe 12 has a check valve 18 which closes against the back flow of liquid into the sump, and the discharge line 20 has a check valve 20, which closes against the back flow of liquid to the pump. A manually operated valve 22 may also be provided in the discharge line 16, by which the system may be cut off from discharging sewage to a downstream location.

In disposal systems of this kind air is frequently trapped in the pump when the pump is out of operation for a substantial period of time and provision must be made for the bleeding ofl or dumping of the air upon starting of the pump to allow the system to operate satisfactorily.

'In the present invention an air outflow line 24 is connected into the discharge line 16 at a point above the pump 14 which outflow line leads back into the sump 10. This outflow line may be of relatively large diameter to avoid the clogging of the same with debris entrained in the sewage' and has a flexible section 26, formed of a material such as rubber or other suitable flexible material which may be flattened or collapsed to shut off the outflow therethrough.

For the purpose of closing the flexible tubular section 26 and allowing the same to open, diaphragm mechanism is provided, which includes a diaphragm casing 28 of a usual kind, forming a diaphragm chamber 30, which is divided by a flexible diaphragm 32. The casing 28 may be suitably rigidly supported on the outflow line, above the flexible section 26, as by means of U-clamps or brackets 34.

The casing 28 also carries an upper tube compressor element 36, which may take the form of a plate having a downwardly facing rounded face 38 positioned for engagement with the flexible section 26, mediate its ends, and a plate 40 is rigidly attached to the casing, as by means of bolts 42 surrounded by tubular spacers 44, which plate extends beneath the tube 26 in downwardly spaced relation thereto.

A pair of spaced apart actuator members 42, 42, are connected at their upper ends to the diaphragm 32 and are slidably extended downwardly therefrom through perforations in the casing 28 and through the plate 40, and carry at their lower ends a plate 44 for vertical movement with the diaphragm.

A lower tube compressor element 46 carried by the actuator members 42, 42 for movement therewith above the stationary plate 40 and is formed with an upper rounded face 48 positioned for engagement with the tube 26 opposite the compressor element 36. Yieldable means, such as the coil spring 50 is positioned between the plates 40 and 44 for coaction therewith to yieldingly urge the plates 40 and 44 and the actuator elements 36 and 46 in a direction to allow the tube 26 to open to permit the outflow of air through the outflow line 24. Thus, upon upward movement of the diaphragm 32 in the casing 28 the actuator elements 36 and 46 will coact to close the flexible tube 26 and upon downward movement of the diaphragm under the influence of the spring 50 the actuator elements will be moved apart to allow the tube 26 to open.

For the purpose of moving the diaphragm 32 upwardly to close the tube 26, a conduit 52 is connected at one end in communication with the chamber 30 above the diaphragm and at its other end to a port 54 in the housing 56 of a control or pilot valve generally designated 58. The pilot valve has an internal seat 60 through which air may flow to the atmosphere and a seat 62 through which fluid may flow from the conduit 52 through a port 64, which is connected through a conduit 66 to the intake or suction side of the pump 14. The pilot valve 58 has a valve member 68 movably disposed in the housing 56 for movement to one position to open the seat 60 to atmosphere while closing the seat 62 and to another position to close seat 60 to atmosphere and open the seat 62 for the outflow of fluid through conduits 52 and 66. The valve member 68 is yieldingly urged in a direction to close seat 62 and open seat 60 by a coil spring 70 which bears at one end against a spring seat member 72 carried on the upper end of an upper stem 74 on the valve member and at its other end against a stationary spring plate 76 attached to the housing 58, as by means of bolts 78. The spring 70 may be suitably enclosed, as by means of a cover 80 whose lower end is open to the atmosphere.

The upper stem 74 of valve member 68 is slidably extended through the housing 58 and is provided with suitable means, such as external slots 82 through which fluid may flow to atmosphere.

The valve member 68 also has a lower stem 84 which is slidably extended through the housing 58 into a fitting 86 connected into the outflow line 24 and within which the lower stem is connected to a flexible diaphragm 88, positioned to be urged upwardly in the fitting against the downward pressure of the spring 70 when all air has been removed from the pump 14 and liquid starts to flow through the fitting. Suitable means such as the O-ring 90 is provided on the lower stem 84, disposed in an external groove in the stem provided therefor, to form a fluid-tight seal between the lower stem and fitting.

A passageway 89 is provided leading from the interior of the fitting 86 above the diaphragm 88 to the exterior through which air may flow during movement of the diaphragm.

The fitting 86 may be of a type having two inlet openings and 87 either of which may be connected in communication with the discharge line 16 while the other is closed by a screw plug 91, as shown in FIGURE 2. By this arrangement the fitting may be connected to the discharge line by a horizontally extending pipe 24' as shown in FIGURE 2 while opening 87 is closed, or the fitting may be connected to the discharge line 16 by a vertically extending pipe 24", as shown in FIGURE 3, while opening 85 is closed by a plug 93. In the event that there should be doubt as to whether the inflow of liquid horizontally through opening 85 will be suflicient to actuate the diaphragm 88, then the pipe 24" may be connected into opening 87, so that the vertical inflow of liquid into the fitting 86 will impinge directly against the diaphragm 88 to move the same upwardly. In either case the flow of air escaping through the outflow line will be insufficient to move the diaphragm upwardly, but such upward movement will take place when liquid is flowing through the fitting.

As shown in FIGURE 3 the diaphragm casing 28 may have a central, internally threaded opening 92 in the upper wall thereof into which a bushing 94 is threaded, through which an adjusting screw 96 extends into the chamber 30 for engagement with the diaphragm 32 to limit upward movement of the diaphragm, whereby the extent of closing of the flexible pipe section 26 may be adjusted as desired. Under some conditions it may be desirable to merely restrict the outflow through the line 24 instead of completely closing the line against the outflow of liquid therethrough and such outflow may be regulated as desired by the adjusting screw 96.

In the operation of the equipment constructed and arranged as described above, when the system is inactive there will be no reduced pressure in the pump inlet, and the pilot valve will be in its down position, allowing the inflow of air from the atmosphere into chamber 30 above the diaphragm 32, and the spring 50 will be effective to move the diaphragm downwardly to allow tube 26 to open fully.

Upon starting of the pump 14, the tube 26 will remain open to allow the outflow of air from the discharge line 16 therethrough until all of the air has passed out, whereupon an upward pressure will be applied to the diaphragm 88 in fitting 86 by the flow of liquid through the fitting to move the pilot valve 68 to close seat 60 and open seat 62. Suction from the inlet side of the pump will then be applied to the diaphragm 32 through conduits 66 and 52 to flex the diaphragm upwardly against the pressure of spring 50 to move the actuator element 48 toward actuator element 36 to close the flexible tube 26 thus shutting off the outflow of liquid through outflow line 24 during the pumping of the sewage.

When the pump 14 is again stopped, the suction through conduits 66 and 52 will cease and the pressure of the liquid in fitting 86 will fall, thus allowing valve 68 to be moved by spring 70 to close seat 62 and open seat 60, whereupon chamber 30 above diaphragm 32 Will be opened to atmosphere allowing spring 50 to move actuator element 46 away from actuator 36 and tube 26 to open fully.

It will, of course, be apparent that the outflow line 24 may be of relatively large diameter to prevent the clogging of the same by debris of the kind likely to be entrained in sewage, and that the closing of the outflow line when all of the air has escaped from the pump will eflectively prevent loss of efliciency in the system which would result from the continued outflow of liquid back to the sump during the pumping operation.

The invention is disclosed herein in connection with a particular embodiment of the same, which it will be understood is intended by way of illustration only, it being apparent that various changes can be made in the construction and arrangement of the parts within the spirit of the invention and the scope of the appended claims.

Having thus clearly shown and described the invention, what is claimed as new and desired to secure by Letters Patent is:

1. In a liquid pumping system the combination with a pump, inlet means for supplying a liquid to be pumped to said pump and a discharge pipe through which fluid may flow from the pump to a higher elevation, of means for allowing the escape of air from the pump comprising an outflow line through which fluid may flow out of said discharge pipe from a location above the pump, said outflow line including a tubular portion formed of flexible material, and means responsive to the flow of liquid through said outflow line for closing said flexible portion.

2. The liquid pumping system as claimed in claim 1, wherein said means for closing said flexible portion of said outflow line comprises a hollow casing forming a diaphragm chamber, a flexible diaphragm extending across and dividing said chamber, means positioned for coaction with said diaphragm to close said flexible portion upon movement of the diaphragm in one direction, yieldable means positioned for coaction with the diaphragm to yieldingly urge the diaphragm in the other direction, and means responsive to a dilference in the pressure of fluid in the inlet of said pump and the pressure of fluid in said outflow line during an outflow of liquid therethrough for moving said diaphragm in said one direction.

3. The liquid pumping system as claimed in claim 2, including means for limiting the movement of said diaphragm in said one direction.

References Qited UNITED STATES PATENTS 1,997,418 4/ 1935 Hornschuch et al. 1,573,931 2/1926 Goyne. 2,757,616 8/1956 Hill et al. 1,080,917 12/1913 Lewis. 2,394,932 2/ 1946 Mueller. 2,734,460 2/ 1956 Deters et al. 3,078,806 2/ 1963 Marlowe. 3,276,384 10/1966 Boone et al. 3,370,604 2/1968 Napolitano. 3,381,618 5/1968 Napolitano.

FOREIGN PATENTS 401,149 8/ 1924 Germany.

HENRY F. RADUAZO, Primary Examiner

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