Submersible pumps are used throughout the world to pump water out of various well configurations. A submersible pump typically has a plurality of impellers which work in series to develop pressure within the pump. The pressurized water is then expelled from the pump discharge and is therefore pressurized and available for usage. The installed system will continue to operate effectively as long as there is a sufficient supply of water which covers the suction intake of the pump. If the water level ever drops below the pump suction bracket for any length of time, the water in the pump may “leak” back out of the suction intake. This is a somewhat common occurrence in the water systems industry as the water tables across the U.S., and elsewhere, are constantly fluctuating. When the water well “recovers” (i.e., the water table rises), water once again surrounds the pump suction bracket and the pump should operate properly again.
The problem with many of these typical installations is that the water entering the well and surrounding the entire pump cannot always enter the hydraulics of the pump. Once air has been introduced into the pump assembly, there are no provisions for “purging” the air out of the pump in order to get the water into the hydraulics to move the water to displace the entrapped air. This detrimental condition of entrapped air in a submersible pump is identified by an industry used term called “air-lock” or “vapor-lock”. The pump may continue to run without pumping any water, potentially leading to an eventual catastrophic failure of the entire pump system. This “air-lock” problem can occur in wells that contain high levels of Hydrogen Sulfide or other gasses as well. This gas can build up and displace the water in the hydraulic stages of the pump and cause a “vapor-lock” condition as well.
One prior method that has proven effective to prevent this anomaly is illustrated in FIG. 1, wherein a bypass hole 10 is located in the discharge head of a pump 12, or somewhere in the discharge piping (not shown) above a topmost impeller stage 14 of the pump 12. It is imperative that great care is taken in creating the bypass hole 10, as it must be located underneath a first check-valve (not shown) placed in the system. Because the bypass hole 10 is placed above all of the impellers of the pump, there is a great amount of performance lost because of the high pressure water exiting the pump through this hole.
It is an object of the invention to address this and other problems.