Submersible pump apparatus

A submersible pump apparatus for admitting air into the low pressure vortex area of the pump to control the amount of liquid material discharged, and including an improved vent and spray system for venting air from the impeller and for directing liquid material onto the pump motor exterior for cooling.

The additional subject matter of the present application includes material 
relating to means for discharging liquid material and venting air from the 
back shroud area adjacent the pump impeller to facilitate self-priming, 
reduce thrust bearing loads, and for cooling of the pump drive motor. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to submersible pump apparatus whose liquid 
material output can be varied. 
2. Description of the Prior Art 
In the submersible pump disclosed in my U.S. Pat. No. 4,134,711, issued 
Jan. 16, 1979, which is designed for location in a sump or the like, a 
relatively inexpensive and simple way is shown to vary the amount of 
liquid material pumped to accomodate differential rates of flow of the 
liquid material into the sump. However, there is lacking a completely 
satisfactory way to vent air from the back shroud area of the pump 
impeller to facilitate self-priming and to reduce thrust bearing loads. 
Further, the venting hardware which is shown for combining the venting 
function with the spray system for cooling the pump motor is relatively 
exposed, and it is therefore susceptible to accidental damage. 
Prior art devices other than that disclosed in my patent typically either 
intermittently operate the pump motor according to the sensed level of the 
liquid material, or control the rate of liquid material discharged by 
varying the speed of rotation of the pump impeller. Thus, the impeller 
rotates at higher speeds when the sump is relatively full, and rotates at 
lower speeds when the liquid level decreases. The impeller speed has been 
controlled in a number of ways in the prior art. Some devices employ an 
oil bath or magnetic clutch to vary the impeller speed, while maintaining 
the speed of the drive motor constant. Other devices vary the speed of the 
drive motor itself, as by frequency control or the like. All of such 
systems tend to be relatively expensive and complex. 
The present apparatus is similar to the apparatus of my patent, controlling 
the quantity of liquid material by aspiration or injection of air, but it 
includes an improved vent and spray apparatus. 
SUMMARY OF THE INVENTION 
According to the present invention, submersible pump apparatus is provided 
which is adapted for location in a sump or the like, and which includes a 
motor case, a driving motor, an impeller case, and an impeller located in 
the impeller case, the impeller defining a back shroud space between its 
upper face and the confronting, superjacent portion of the impeller case. 
The impeller is rotatable to develop a low pressure vortex below the 
impeller in the area adjacent the impeller inlet. 
The apparatus includes a vent which opens at one end into the back shroud 
space and at the other end opens to the exterior of the impeller case. 
Whenever air is drawn or injected into the low pressure vortex area of the 
pump for controlling the amount of liquid discharged, the air collecting 
in the back shroud space is constantly vented to facilitate operation of 
the impeller and reprime the pump. 
The present apparatus includes spray heads coupled to the air vent, and 
angularly inclined to direct liquid material onto the motor case for 
cooling, the liquid material being drawn from the back shroud space along 
with the vented air and other gases which may be present. 
The present pump apparatus is operative in conjunction with various means 
for controlling air admission to the low pressure vortex area of the pump 
impeller, including means providing natural air aspiration through a 
conduit opening to atmosphere, and means for injecting air supplied by a 
suitable compresser. Such air supply means normally include suitable 
valving for initiating air aspiration or injection as soon as the level of 
liquid material in the sump drops below a predetermined level, the rate of 
air flow increasing as the liquid level drops so as to maintain the liquid 
level within a desired range. However, the present vent and spray means is 
so effective in maintaining impeller pumping at high rates of air 
injection that it makes possible the use in some sump operations of a pump 
apparatus not having any liquid material level control. In such an 
application, the liquid material level falls to a level approximating that 
of the pump inlet, and air is immediately drawn into the inlet and into 
the impeller vortex area. Instead of a complete loss of prime and 
discontinuation of further pumping, as would occur with most prior art 
pumps, air is vented from the back shroud area constantly so that the pump 
can commence normal operation as soon as the liquid material level rises. 
In addition, in such an unsubmerged condition a prior art pump motor would 
become overheated and burn out. With the present improved vent and spray 
apparatus, the available water which is drawn into the back shroud area is 
sprayed onto the motor case for cooling. 
Other objects and features of the invention will become apparent from 
consideration of the following description, taken in connection with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, there is illustrated an elongated pump 10 
adapted for vertical orientation in a sump 12 and including a motor case 
14 and a drive shaft 16 extending downwardly through a shaft seal 17 from 
a pump motor 19 located within the case 14 and generally indicated in 
dotted outline in FIG. 3. The shaft 16 is coupled to an impeller 18 
located in an impeller case 20 for rotation of the impeller 18 to pump 
liquid material out of the sump 12. 
The usual submersible pump is sealed against fluid entry for operation in a 
submerged condition, and is designed to be cooled by the liquid material 
within which it is submerged. Dangerous overheating can occur if such a 
pump is not operated in a submerged condition, and such overheating may 
result in burning or explosion of the motor. Under normal circumstances a 
sump within which such a prior art pump is to operate must be made deep 
enough to cover the pump motor case during all usual fluctuations in the 
level of the liquid material being pumped. Such a deep sump is shown in 
FIG. 1. 
I have heretofore disclosed a system whereby a shallower sump can be 
employed, the pump being cooled at all liquid levels down to and including 
the level of the pump inlet. The present system is an improved means for 
accomplishing the foregoing as well as other objects. 
Referring to FIG. 1, the pump 10 is provided with power by means of a cable 
(not shown) connected to an external power source. Liquid material to be 
pumped enters an inlet pipe 25 and is pumped out of the sump 12 through a 
discharge pipe 26 connected at its flanged end 28, as seen in FIG. 2, to 
the impeller case 20 by a pair of nut and bolt assemblies 30, only one of 
which is illustrated. 
In contrast to most prior art systems, the present submersible pump 
apparatus does not operate the pump motor in an on-off manner as the level 
of liquid material in the sump 12 fluctuates. Instead, the pump operates 
continuously, the volume of liquid material discharged being modulated to 
adjust or maintain the liquid material at the desired level. 
The impeller case 20 includes a plurality of supporting legs 36 which space 
the impeller inlet 38 a suitable distance above the floor of the sump 12, 
as best seen in FIGS. 1 and 5. In a vertically oriented submersible pump 
there is characteristically a generally conical, low pressure vortex area 
66, as seen in FIG. 2, having its base adjacent the impeller inlet 38 and 
its apex just below the impeller 18. Material to be pumped is drawn 
upwardly by this low pressure region into the impeller 18. The plurality 
of radially-directed impeller blades 68 thrust the material outwardly, the 
impeller 18 being provided with an angularly inclined flange which directs 
the outwardly thrust material downwardly and into the discharge pipe 26. 
In the embodiment of FIG. 1 in which air can be naturally aspirated into 
the low pressure vortex area 66, one end of a conduit 64 is connected at 
its lower end to the impeller case 20 in fluid communication with the 
interior of the case 20 adjacent the base of the vortex area 66, as seen 
in FIG. 2. The upper end of the conduit 64 is open to atmosphere above the 
level of the liquid material. This enables atmospheric air to be aspirated 
or drawn into the area 66. Controlling the flow of this air is a 
relatively simple and inexpensive means for varying the output of the pump 
as desired, and independently of the rate of rotation of the pump 
impeller. The effect of the air is to displace some of the liquid material 
which would otherwise be pumped. 
Control of the rate of air flow through the conduit 64 is achieved in the 
system of FIG. 1 by use of a float mechanism including a buoyant float 72 
connected by an arm 74 to any suitable air valve 76 disposed in the 
conduit 64. Valve 76 may be any commercially available valve operative to 
regulate air flow through it according to the position of an associated 
actuating lever, such as the float arm 74, as will be apparent to those 
skilled in the art. 
The float 72, arm 74 and valve 76 are so mounted that the float 72 swings 
between an upper level 78 and a lower level 80. As the float drops, the 
valve 76 opens wider to permit more air to be aspirated through the 
conduit 70, decreasing the quantity of material pumped. Conversely, when 
the float rises the valve begins to close and the amount of air aspirated 
decreases, increasing the quantity of material pumped. Full closure of the 
valve 76 would allow the pump 10 to operate at maximum capacity. In this 
manner, the float 72 maintains the liquid level in the sump between the 
levels 78 and 80. 
The system of FIG. 5 is generally similar to that of FIG. 1, except that 
the air is supplied by an air compressor 82. As in the embodiment of FIG. 
1, the volume of air supplied is controlled to vary the air and liquid 
material mixture passing out of the discharge conduit 26 such that the 
liquid level in the sump is maintained between the levels 78 and 80. Such 
control may be accomplished in any suitable fashion, the system 
illustrated being merely exemplary. In the system illustrated some of the 
compressed air is directed into a bubbler tube 84 which extends downwardly 
into the sump, the open lower end of the tube being located just below the 
lowest desired level for the liquid material. 
A surface control unit 86, of a type well-known to those skilled in the 
art, is responsive to the difference in back pressure at the lower end of 
the tube 84 as the level of the liquid material varies. The surface 
control unit 86, which is energized by a power source 88 acting through a 
transformer 90, generates an output signal operative to control a 
modulating solenoid air valve 90 which is located in the air line which 
extends from the compressor 82 to the conduit 64a that is in communication 
with the low pressure vortex area of the pump 10. 
Operation of the system of FIG. 5 is analogous to that of the system of 
FIG. 1, except that air is injected into the low pressure vortex area of 
the pump 10 under pressure, rather than by natural aspiration. 
As previously indicated the present air venting and liquid spray system is 
operative with pumps not associated with any liquid level control system. 
Thus, assuming that the liquid material level occasionally falls to the 
level of the impeller inlet 38, air will be aspirated into the inlet 38 
and quickly reduce the volume of liquid material passing out of the 
discharge pipe 26. Such air dilution of the discharged liquid material 
continues until the level of liquid material rises above the impeller 
inlet 38. Air dilution in this and the other applications does not 
adversely affect pump operation. The desired reduction in the volume of 
liquid material is always accompanied by a cooling spray of any liquid 
material available in the back shroud area, and by venting of air from 
that area so that the pump immediately and completely reprimes when air 
aspiration or injection is halted. 
The particular vent and spray means empolyed comprises a plurality of vent 
passages 94 which are drilled through an upper plate 96 of the impeller 
case 20, the passages being inclined at approximately a 45.degree. angle 
as best seen in FIG. 4, to accept a corresponding plurality of spray heads 
98. The angular inclination of the spray heads 98 is operative to direct 
liquid material upwardly against the motor case 14 for cooling the case at 
all times that there is any liquid material available in the back shroud 
area 100. 
The back shroud pressure area 100 is generally characterized by a pressure 
which is significantly higher than the pressure below the impeller 18, 
causing a relatively high load on the thrust bearings. The described 
discharge of water from the back shroud pressure area 100 thus has another 
important advantage, it reduces pressure in the area 100 and thereby 
reduces loading of the thrust bearings and prolongs the life of the 
bearings. 
Integral location of the spray heads 98 in the casing and adjacent the base 
of the motor case 14 eliminates any need for protruding spray rings and 
connecting tubing, either at the top or bottom of the motor case. 
From the foregoing it is seen that use of the spray heads 98 accomplishes a 
number of important objects. It provides an inexpensive and simple form of 
vent and spray hardware. It provides a means for quickly venting air from 
the back shroud pressure area 100; and it enables reduction of pressure in 
the area 100 by withdrawal of liquid material for spraying upon and 
cooling the motor case 14. 
Various modifications and changes may be made with regard to the foregoing 
detailed description without departing from the spirit of the invention.