Pumps – Condition responsive control of pump drive motor – Responsive to accumulation of pumped liquid in receiver
Reexamination Certificate
2002-01-07
2003-10-28
Tyler, Cheryl J. (Department: 3746)
Pumps
Condition responsive control of pump drive motor
Responsive to accumulation of pumped liquid in receiver
C417S040000, C417S044110
Reexamination Certificate
active
06638023
ABSTRACT:
FIELD OF THE INVENTION
The subject invention relates generally to a system and methods for adjusting operating parameters of computer controlled pumps where solids may be encountered during a pumping operation. The present invention provides for overcoming buildups on a capacitance level sensor as well as preventing debris from causing a pump to stop functioning properly. The output signal of a level sensor may be monitored so as to detect and account for variations therein. The power draw or current of the pump may also be monitored so as to detect and account for the presence of solids.
BACKGROUND OF THE INVENTION
A variety of pumps such as grinder pumps, for example, are widely used in many different applications to pump liquids containing various forms of solids. Such pumps are often installed in tanks or other containers suitable for storing fluids. The pumps are turned on and off automatically by external or internal liquid level controls. The level controls typically provide some sort of indicator or signal that is transmitted to the pump. The value of the signal is adapted to correspond to the level of fluid within the tank and the pump is programmed to turn on and off at predetermined values of the signal. During normal operation, the level sensor output signal is used to determine when the pump should turn on and off for purposes of pumping liquid from a tank. Solids and/or debris encountered during a pumping operation often become attached to the level sensor element, i.e. the input portion of the level control system located within the tank. To ameliorate the effects of small buildups on the sensor element, a software program may be utilized to periodically recalibrate the level sensor so as to avoid variations in the value of the output signal as it corresponds to the fluid level. However, in cases of extreme buildup on the level sensor element, the level sensor's output signal will become attenuated causing significant variations in the value of the output signal that corresponds to the fluid level. If the attenuation is great enough, no amount of fluid level increase will initiate a pumping cycle thereby potentially causing an overflow situation.
Debris encountered during a pumping operation may also cause problems in regard to the pump itself. Normally, debris located within the tank that ends up being drawn into the pump inlet is ground up and exits the pump outlet. Problems may arise when the fluid level drops below the point at which the pump is programmed to turn off and consequently the level controls turn the pump off while it is in the process of grinding something. In such situations, the pump may have insufficient torque to restart when the fluid level goes back up above the point at which the pump is programmed to turn on. If the pump is not capable of restarting, the debris must be manually cleared from the pumps' cutters. Obviously, manually clearing the pumps' cutters so as to enable the pump to restart is time consuming and expensive.
It is therefore desirable to provide a system for adjusting pump operating parameters so as to account for the detrimental effects that may be caused by solids encountered during a pumping operation.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a system and methods for adjusting operating parameters of computer controlled pumps where solids may be encountered during a pumping operation. The system and methods enable operating parameters of a pump to be adjusted in accordance with the degree to which solids are affecting a pumping operation.
In one embodiment of the present invention, there is provided a method for adjusting pump operating parameters for at least one pump to accommodate solids encountered during a pumping operation, the method comprising the steps of:
a) providing a level sensor adapted to provide an output signal corresponding to a fluid level;
b) assigning a value of the output signal to correspond to a predetermined maximum fluid level;
c) assigning a value of the output signal to correspond to a predetermined minimum fluid level;
d) programming the pump to turn on when the output signal is at a certain predetermined value and off when the output signal is at another predetermined value, the predetermined values being less than the value that corresponds to the maximum fluid level and greater than the value that corresponds to the minimum fluid level; and
e) monitoring the values of the output signal that correspond to the maximum and minimum fluid levels so as to periodically update the values at which the pump will turn on and off in accordance with variations that may occur in the values of the signal that correspond to the maximum and minimum fluid levels.
In another embodiment of the present invention, there is provided a method for adjusting pump operating parameters for at least one pump to accommodate solids encountered during a pumping operation, the method comprising the steps of:
a) providing a level sensor adapted to provide an output signal corresponding to a fluid level;
b) assigning a value of the output signal to correspond to a predetermined maximum fluid level;
c) assigning a value of the output signal to correspond to a predetermined minimum fluid level;
d) programming the pump to turn on when the output signal is at a certain predetermined value and off when the output signal is at another predetermined value, the predetermined values being less than the value that corresponds to the maximum fluid level and greater than the value that corresponds to the minimum fluid level; and
e) monitoring the values of the output signal that correspond to the maximum and minimum fluid levels so as to periodically update the values at which the pump will turn on and off in accordance with variations that may occur in the values of the signal that correspond to the maximum and minimum fluid levels.
In another embodiment of the present invention, there is provided a method for adjusting pump operating parameters for at least one pump to accommodate solids encountered during a pumping operation, the method comprising the steps of:
a) providing a level sensor adapted to provide an output signal corresponding to a fluid level;
b) assigning a value of the output signal to correspond to a predetermined maximum fluid level;
c) assigning a value of the output signal to correspond to a predetermined minimum fluid level;
d) programming the pump to turn on when the output signal is at a certain predetermined value and off when the output signal is at another predetermined value, the predetermined values being less than the value that corresponds to the maximum fluid level and greater than the value that corresponds to the minimum fluid level;
e) taking a first reading of the value of the output signal generated by the level sensor in response to an alarm signal indicating that the level of fluid is above the maximum fluid level and that the pump has not begun pumping;
f) adjusting the value of the output signal that corresponds to the maximum fluid level so that the value of the output signal taken as the first reading now corresponds to the maximum fluid level;
g) reducing the level of fluid to below the minimum fluid level;
h) taking a second reading of the value of the output signal generated by the level sensor while the fluid level is below the minimum fluid level;
i) adjusting the value of the output signal that corresponds to the minimum fluid level so that the value of the output signal taken as the second reading now corresponds to the minimum fluid level; and
j) using the values of the output signal taken as the first and second reading to calculate new output signal values at which the pump will turn on and off.
In another embodiment of the present invention, there is provided a system pump operating parameters of at least one pump may be adjusted to accommodate solids encountered during a pumping operation, the system comprising:
a) at least one pump;
b) a level sensor adapted to provide an output signal corresponding to a fluid level whe
Drinker Biddle & Reath LLP
Little Giant Pump Company
Tyler Cheryl J.
LandOfFree
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