Patent Application
20130336763
1. Field of the Invention
This invention relates to a pump; and more particularly, relates to a centrifugal pump.
2. Description of Related Art
It is known in the art that if, e.g., a centrifugal pump, is turned on prior to being submerged air can become trapped inside of the housings containing the impellers causing them to pump a gas/liquid mixture instead of the pure liquid mixture they were designed to pump. When this occurs the pump tends to fail to pump water and the air must be expelled or pushed out of the system before the pump can operate as intended. When the pump fails. this situation is known as air lock.
There are known devices whose purpose and intention is to prevent such air lock in, e.g., centrifugal pumps.
By way of example, U.S. Pat. No. 5,545,012, entitled, “Soft Star Pump Control System” discloses a technique, having a system that detects the presence of air lock by measuring the current through the pump motor at any given time. Should the pump detect air lock it uses a switching circuit to the lower the motor voltage and slowly ramp it up from a low value to its full value. However, the system in U.S. Pat. No. 5,545,012 does not always clear the air lock and is more complex than the system proposed in this document. The system also relies on the amount of current going through the motor which can vary greatly depending on the degree of air lock that a centrifugal pump is experiencing or the amount of charge left on a battery powering the system.
U.S. Pat. No. 4,087,994 entitled, “Centrifugal pump with means for precluding airlock” discloses another technique, having a pump with an impeller that contains finger-like protrusions designed to mix the trapped air with the water in the pump so it can be centrifuged out with the water.
U.S. Pat. No. 4,913,620, entitled “Centrifugal water pump,” discloses yet another technique, which consists of a pump whose impeller housing chamber has two walls. One of these walls has a radius close to the size of the impeller used in the pump and the other has a larger radius. There are also two terminal walls which direct the water flow to the outlet and break up any air and fills in any space where it could collect.
However, the techniques in U.S. Pat. Nos. 4,087,994 and 4,913,620 are both unnecessarily complex and because of this are cost prohibitive in many situations.
In view of this there is a need for a new, better and more cost effective way to prevent air lock, e.g., in centrifugal pumps.
According to some embodiments, the present invention may take the form of apparatus featuring a pump and a control circuit. The pump may include an impeller housing configured with a slit at the top for trapped air to leave the impeller housing once the pump has been submerged. The control circuit may be configured to cycle the pump on and off for a predetermined number of cycles so that the trapped air will float to the top and be expelled out the slit when the pump is cycled off.
According to some embodiments, the present invention may include one or more of the following features:
The control circuit may be configured to leave the pump on after the predetermined number of cycles.
The control circuit may be configured to provide signaling to cycle the pump on and off for the predetermined number of cycles so that the trapped air will float to the top and be expelled out the slit when the pump is cycled off.
The apparatus may be configured with a relay arranged between the pump and the control circuit, the relay configured to respond to the signaling provided from the control circuit and provides relay signaling to cycle the pump on and off for a predetermined number of cycles so that the trapped air will float to the top and be expelled out the slit when the pump is cycled off.
The apparatus may be configured as a pumping system having a combination of the pump and the control circuit.
The pump is configured to contain the control circuit, so as to have the control circuit arranged therein.
The pump is configured with a motor coupled to an impeller via a shaft.
The pump is configured as a centrifugal pump.
In operation, a so-called stutter start anti-air lock system may consist of two different mechanisms through which air lock in a pump is overcome. First, there is a small slit, hole or orifice which has been cut into the highest point of the impeller housing that allows air trapped inside the unit to escape from inside the impeller housing to outside the impeller housing. Secondly, there is a stuttered starting mechanism which cycles the pump on and off for a predetermined duration until the air lock has been cleared from inside the impeller housing.
By adding this anti air-lock slit, a place is provided for the trapped air to leave the impeller housing once the pump has been submerged. Even with the addition of the slit to the impeller housing, the pump can still become air locked. For example, even with the impeller constantly spinning the air does not necessarily seep out of the added slit and may remain inside the impeller housings. This is where the ON/OFF cycle provided by the control circuit may be implemented. By turning the pump off, the air will float to the top of the pump's impeller housing or internal chamber and be expelled out of the slit.
It is during these so-called “off” times that the air is expelled through the top of impeller housing and the pump fills with liquid. When the motors return to the “on” state, it will be filled with liquid and able to function as intended.
One advantage of the present invention is that it provides a new, better and more cost effective way to prevent air lock, e.g., in centrifugal pumps.
These and other features, aspects, and advantages of embodiments of the invention will become apparent with reference to the following description in conjunction with the accompanying drawing. It is to be understood, however, that the drawing is designed solely for the purposes of illustration and not as a definition of the limits of the invention.
The drawing, which is not necessarily to scale, include the following Figures:
In the following description of the exemplary embodiment, reference is made to the accompanying drawing, which form a part hereof, and in which is shown by way of illustration of an embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized, as structural and operational changes may be made without departing from the scope of the present invention.
By way of example,
The control circuit 20 (see
By way of example,
In contrast to that in
Relays, and techniques for controlling and cycling such relays, are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind thereof either now known or later developed in the future.
Embodiments are also envisioned in which the control circuit 20 is coupled directly to the motor of the pump 12 and to provide the signaling to turn the motor (see
The control circuit 20 may be implemented in, or form part of, a signal processor module having a signal processor, and/or a printed circuit board (PCB), or some combination thereof.
Printed circuit boards (PCBs) are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind thereof either now known or later developed in the future for implementing the runtime on/off cycling functionality of the present invention.
By way of example, the functionality of the control circuit 20, the PCB, the associated signal processor, and/or any associated signal processing may be implemented using hardware, software, firmware, or a combination thereof, although the scope of the invention is not intended to be limited to any particular embodiment thereof. For example, in a typical software implementation, the signal processor may take the form of one or more microprocessor-based architectures having a processor or microprocessor, a random and/or read only access memory (RAM/ROM), where the RAM/ROM together forming at least part of the memory, input/output devices and control, data and address buses connecting the same. A person skilled in the art would be able to program such a microprocessor-based implementation with computer program code to perform the functionality described herein without undue experimentation. The scope of the invention is not intended to be limited to any particular implementation using technology either now known or later developed in the future. Moreover, the scope of the invention is intended to include the signal processor being a stand alone module, or in some combination with other circuitry for implementing another module. Moreover still, the scope of the invention is not intended to be limited to any particular type or kind of signal processor used to perform the signal processing functionality, or the manner in which the computer program code is programmed or implemented in order to make the signal processor operate. A person skilled in the art without undue experimentation would appreciate and understand how to develop or write a suitable software program or algorithm for running on, e.g., such a PCB-based control circuit, so as to implement the functionality set forth herein.
Such a PCB-based control circuit and/or the associated signal processor may include one or more other sub-modules for implementing other functionality that is known in the art, but does not form part of the underlying invention per se, and is not described in detail herein.
In one particular embodiment, the present invention may take the form of, or may be implemented in, a centrifugal pump encased in such a housing that directs the water projected from the pump's impeller into an exit tube. In the centrifugal pump, there exists, or may be configured, a small hole or slit formed in this casing or housing through which to expel the trapped air when the pump is submerged. The centrifugal pump and/or pumping system may include the control circuit like element 20 whose function is to cycle, e.g., the motor of the centrifugal pump on and off for some predetermined time upon powering of the unit or pumping system, consistent with that set forth herein.
The pump 12, like that shown in FIGS. 2 and 4-7, may also include, e.g., other parts, elements, components, or circuits that do not form part of the underlying invention, including inlet ports, outlet ports, pressure transducers, wiring for coupling the motor to the control circuit 20, and are thus not identified and described in detail herein.
Moreover, pumps having motors and impeller arranged or configured thereon are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind thereof either now known or later developed in the future.
Possible applications are envisioned to include any type or kind of pump or rotary equipment that may be submerged and contain trapped air, e.g., in its housing or impeller housing, including but not limited to centrifugal pumps or other types or kinds of submersible pumps either now known or later developed in the future.
Scope of the Invention
Although described in the context of particular embodiments, it will be apparent to those skilled in the art that a number of modifications and various changes to these teachings may occur. Thus, while the invention has been particularly shown and described with respect to one or more preferred embodiments thereof, it will be understood by those skilled in the art that certain modifications or changes, in form and shape, may be made therein without departing from the scope and spirit of the invention as set forth above.
This application claims benefit to provisional patent application Ser. No. 61/659,631, filed 14 Jun. 2012, which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61659631 | Jun 2012 | US |
