METHODS AND APPARATUS FOR PRESSURE COMPENSATION IN A MASS FLOW CONTROLLER
First Claim
1. In a flow controller including a flow sensor coupled to a fluid flow path having an inlet side and an outlet side, the flow sensor being adapted to provide a sensor output signal indicative of a sensed fluid flow through the flow path, a method comprising acts of:
- measuring at least one pressure of the flow path; and
adjusting the sensor output signal based on the act of measuring the at least one pressure.
3 Assignments
0 Petitions
Accused Products
Abstract
Performance of mass flow controller may be vulnerable to pressure transients in a flow path to which the controller is coupled for the purpose of controlling the fluid flow. A system and method are provided for reducing or eliminate performance degradations, instabilities, and/or inaccuracies of a mass flow controller caused by changes in the pressure environment. In particular, a method and system are provided for compensating for pressure transients in the pressure environment of a flow path and mass flow controller.
91 Citations
67 Claims
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1. In a flow controller including a flow sensor coupled to a fluid flow path having an inlet side and an outlet side, the flow sensor being adapted to provide a sensor output signal indicative of a sensed fluid flow through the flow path, a method comprising acts of:
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measuring at least one pressure of the flow path; and adjusting the sensor output signal based on the act of measuring the at least one pressure. - View Dependent Claims (2, 3, 4, 12)
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5. A method of modifying a sensor output signal from a flow sensor, the method comprising acts of:
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constructing a false flow signal corresponding to a response of the flow sensor due to changes in pressure based on at least one pressure measurement of the flow path; and subtracting the false flow signal from the sensor output signal. - View Dependent Claims (6, 7, 8, 9, 10)
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11. (canceled)
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13. (canceled)
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14. A flow meter comprising:
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a flow sensor adapted to measure fluid flow in a flow path, the flow sensor providing a sensor output signal in response to sensed fluid flow in the flow path; at least one pressure transducer to measure at least one pressure in the flow path, the at least one pressure transducer providing at least one pressure signal related to the respective at least one measured pressure; a compensation filter to receive the at least one pressure signal, the compensation filter adapted to construct a false flow signal approximating a response of the flow sensor to pressure transients in the flow path; and a subtractor to receive the sensor output signal and the false flow signal and to provide a flow signal related to the difference between the sensor output signal and the false flow signal. - View Dependent Claims (15, 16, 17)
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18-27. -27. (canceled)
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28. In a mass flow controller coupled to a flow path, the mass flow controller having a control loop including a flow meter, a controller, a valve actuator and a valve, a method comprising acts of:
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measuring at least one pressure in a fluid path environment; providing at least one pressure signal indicating at least one pressure measurement; determining at least one compensation signal based on at least one pressure measurement; and applying the at least one compensation signal to the control loop of the mass flow controller. - View Dependent Claims (29, 30, 66, 67)
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31-64. -64. (canceled)
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65. A system for controlling a fluid flow along a flow path, the system comprising:
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a mass flow controller including a flow meter adapted to sense fluid flow in a fluid flow path and provide a flow signal indicative of the mass flow rate in the flow path; a valve actuator adapted to receive the drive signal from the controller; a valve for controlling the flow rate in the fluid path, the valve coupled to the fluid flow path and adapted to be controlled by the valve actuator; at least one pressure transducer to measure at least one pressure in a mass flow controller environment and to provide at least one pressure signal indicative of measurement of the at least one pressure; a controller coupled to the flow meter and adapted to provide a drive signal based at least in part on the flow signal; and at least one compensation means to receive at least one pressure signal and to provide at least one displacement compensation signal, the displacement compensation signal added to the drive signal to compensate for valve displacement resulting from pressure gradients.
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Specification