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.
76 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