Extended range proportional valve
First Claim
1. An extended range fluid flow system operated by fluid flow commands, comprising:
- a controller that receives the fluid flow commands and generates control signals in response, each control signal representing a desired frequency and a desired duty cycle;
a power circuit coupled to the controller, the power circuit receiving the control signals and generating fixed frequency pulse width modulated signals in response, each fixed frequency pulse width modulated signal having one of at least two fixed frequencies corresponding to the desired frequency and having one of a plurality of active duty cycles corresponding to the desired duty cycle;
a flow valve, including;
a solenoid actuator that receives the fixed frequency pulse width modulated signals from the power circuit to control the flow rates of fluid passing through the valve, a valve seat, and a flow-shaping element at least partially positioned within the valve seat, wherein the flow shaping element is constructed such that the flow rate of fluid through the valve when operated at a first of the fixed frequency pulse width modulated signals having a first of the at least two fixed frequencies and a first of the plurality of active duty cycles is substantially equal to the flow rate of fluid through the valve when operated at a second of the fixed frequency pulse width modulated signals having a second of the at least two fixed frequencies and the same first active duty cycle.
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Accused Products
Abstract
An extended range proportional valve which can control rates of mass flow over continuous low, intermediate and high ranges has a pilot member mounted on an armature of a solenoid which can be dithered onto and off of a pilot opening in a main valve member which seals a main valve opening to control mass flow rates over the low range by varying the duty cycle and/or frequency of a pulse width modulated current in the solenoid coil. Intermediate and high flow rates are achieved by dithering the pilot valve member with a duty cycle and/or frequency sufficient to raise the main valve member relatively short and relatively long respective distances from the main valve seat.
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Citations
23 Claims
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1. An extended range fluid flow system operated by fluid flow commands, comprising:
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a controller that receives the fluid flow commands and generates control signals in response, each control signal representing a desired frequency and a desired duty cycle;
a power circuit coupled to the controller, the power circuit receiving the control signals and generating fixed frequency pulse width modulated signals in response, each fixed frequency pulse width modulated signal having one of at least two fixed frequencies corresponding to the desired frequency and having one of a plurality of active duty cycles corresponding to the desired duty cycle;
a flow valve, including;
a solenoid actuator that receives the fixed frequency pulse width modulated signals from the power circuit to control the flow rates of fluid passing through the valve, a valve seat, and a flow-shaping element at least partially positioned within the valve seat, wherein the flow shaping element is constructed such that the flow rate of fluid through the valve when operated at a first of the fixed frequency pulse width modulated signals having a first of the at least two fixed frequencies and a first of the plurality of active duty cycles is substantially equal to the flow rate of fluid through the valve when operated at a second of the fixed frequency pulse width modulated signals having a second of the at least two fixed frequencies and the same first active duty cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An extended range fluid flow system operated by fluid flow commands, comprising:
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a control unit receiving the fluid flow commands and generating pulse width modulated signals in response, each pulse with modulated signal having one of at least two fixed frequencies and having one of a plurality of duty cycles;
a valve having a reservoir with an inlet and an outlet, including;
a valve seat positioned in the reservoir between the inlet and the outlet;
a diaphragm positioned across the reservoir;
a pilot tube member attached to the diaphragm and defining a pilot passage, the pilot tube member movable with the diaphragm and having a flow-shaping portion positioned adjacent the valve seat;
a solenoid actuator having a core and operated by the pulse width modulated signals from the control unit, the core movable relative to the pilot tube member to control flow rates of fluid through the valve seat, wherein the flow-shaping portion of the pilot tube member is constructed such that the flow rate resulting from the solenoid actuator operated at a first of the pulse width modulated signals having a first of the at least two fixed frequencies and one duty cycle is substantially equal to the flow rate resulting from the solenoid actuator operated at a second of the pulse width modulated signals having a second of the at least two fixed frequencies and the same duty cycle. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. An extended range fluid flow system operated by fluid flow commands, comprising:
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means for generating pulse width modulated signals in response to the fluid flow commands, each pulse width modulated signal defined by one of at least two fixed frequencies and one of a plurality of duty cycles;
means for controlling fluid flow rates in response to first pulse width modulated signals having a first of the at least two fixed frequencies and in response to second pulse width modulated signals having a second of the at least two fixed frequencies; and
means for affecting flow rates such that the flow rate resulting from one of the first pulse width modulated signals having the first of the at least two fixed frequencies and one of the duty cycles is substantially equal to the flow rate resulting from one of the second pulse width modulated signals having the second of the at least two fixed frequencies and the same duty cycle. - View Dependent Claims (23)
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Specification