Method and apparatus for pump protection without the use of traditional sensors
First Claim
1. A method for controlling the operation of a pump, including a centrifugal pump, centrifugal mixer, centrifugal blower or centrifugal compressor, comprising:
- determining an actual flow value without using a flow or pressure sensor based at least partly on a comparison of speed and power sensed in relation to the current operation of the pump and information contained in a calibrated curve of speed versus closed valve power together with published pump performance data, including best efficiency power, closed valve power and best efficiency flow at rated pump speed;
determining a corrected threshold flow value based at least partly on a flow value associated with an unfavorable operating condition of the pump and corrected based on a relationship between a current operating speed of the pump and a rated operating speed of the pump; and
controlling the operation of the pump based at least partly on a comparison between the actual flow value and the corrected threshold flow value in order to provide pump protection for the pump.
1 Assignment
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Accused Products
Abstract
The present invention provides protection for centrifugal pumps while differentiating between dangerous operating conditions (e.g. dry running, minimum flow and runout) and/or conditions where transient conditions (e.g. closed valve operation) may occur and the protection can be revoked once the condition clears. The methodology utilizes a calculated flow value which can be mathematically determined from a calibrated closed valve power vs speed curve and/or various pump and motor parameters such as speed, torque, power and/or differential pressure or from calibrated flow curves stored in the evaluation device. The calculated flow value is then compared to threshold values of flow associated with these adverse operating conditions.
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Citations
54 Claims
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1. A method for controlling the operation of a pump, including a centrifugal pump, centrifugal mixer, centrifugal blower or centrifugal compressor, comprising:
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determining an actual flow value without using a flow or pressure sensor based at least partly on a comparison of speed and power sensed in relation to the current operation of the pump and information contained in a calibrated curve of speed versus closed valve power together with published pump performance data, including best efficiency power, closed valve power and best efficiency flow at rated pump speed; determining a corrected threshold flow value based at least partly on a flow value associated with an unfavorable operating condition of the pump and corrected based on a relationship between a current operating speed of the pump and a rated operating speed of the pump; and controlling the operation of the pump based at least partly on a comparison between the actual flow value and the corrected threshold flow value in order to provide pump protection for the pump. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 39, 40, 41, 42, 43)
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13. A controller for controlling the operation of a pump, including a centrifugal pump, centrifugal mixer, centrifugal blower or centrifugal compressor, comprising:
at least one module configured to determine an actual flow value without using a flow or pressure sensor based at least partly on a comparison of speed and power sensed in relation to the current operation of the pump and information contained in a calibrated curve of speed versus closed valve power together with published pump performance data, including best efficiency power, closed valve power and best efficiency flow at rated pump speed; determine a corrected threshold flow value based at least partly on a flow value associated with an unfavorable operating condition of the pump and corrected based on a relationship between a current operating speed of the pump and a rated operating speed of the pump; and control the operation of the pump based at least partly on a comparison between the actual flow value and the corrected threshold flow value in order to provide pump protection for the pump. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 44, 45, 46, 47, 48)
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26. A centrifugal pump system or system with other centrifugal device such as a centrifugal mixer, centrifugal blower or centrifugal compressor having a controller for controlling the operation of a pump, including a centrifugal pump, centrifugal mixer, centrifugal blower or centrifugal compressor, the controller comprising:
at least one module configured to determine an actual flow value without using a flow or pressure sensor based at least partly on a comparison of speed and power sensed in relation to the current operation of the pump and information contained in a calibrated curve of speed versus closed valve power together with published pump performance data, including best efficiency power, closed valve power and best efficiency flow at rated pump speed; determine a corrected threshold flow value based at least partly on a flow value associated with an unfavorable operating condition of the pump and corrected based on a relationship between a current operating speed of the pump and a rated operating speed of the pump; and control the operation of the pump based at least partly on a comparison between the actual flow value and the corrected threshold flow value in order to provide pump protection for the pump. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 49, 50, 51, 52, 53, 54)
Specification