Flow control apparatus and program

Patent metadata

Field	Value
Publication number	US-9797520-B2
Application number	US-201314376065-A
Country	US
Kind code	B2
Filing date	Jan 31, 2013
Priority date	Feb 3, 2012
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A flow control apparatus and a program are disclosed herein. A flow control apparatus includes a piezoelectric element coupled to a valve element configuring a flow regulating valve and that works the valve element to regulate a flow, a driving circuit that applies a voltage to the piezoelectric element to drive the piezoelectric element, an accepting means for accepting a target flow, and an output means for outputting a signal corresponding to the voltage applied to the piezoelectric element to the driving circuit, to change the flow so as to coincide with the target flow. When the target flow is changed, the output means transiently outputs a signal corresponding to a voltage value different from a target voltage value corresponding to the target flow after the change, and then the output means outputs a signal corresponding to a voltage change converging at the target voltage value.

First claim

The invention claimed is:

1. A flow control apparatus comprising:
a piezoelectric element that is coupled to a valve element configuring a flow regulating valve and that works the valve element to regulate a flow;
a driving circuit that applies a voltage to the piezoelectric element to drive the piezoelectric element;
an accepting unit that accepts a target flow; and
an output unit that outputs a signal, corresponding to the voltage applied to the piezoelectric element, to the driving circuit to change the flow so as to coincide the flow with the target flow accepted by the accepting unit, wherein
if the flow regulating valve is closed when the target flow is changed to a new target flow, the output unit transiently outputs, in response to the change to the new target flow, the signal to cause the driving circuit to apply the voltage at a greater amplitude than a target voltage value, wherein application of the target voltage value to the piezoelectric element results in the new target flow, and then the output unit outputs the signal to cause the driving circuit to apply the voltage so the voltage converges from the greater amplitude to the target voltage value, which maintains the valve in an open position to provide the new target flow.

2. The flow control apparatus according to claim 1 , wherein
in response to the change to the new target flow when the flow regulating valve is closed, the output unit outputs the signal as a spike-like signal to the driving circuit.

3. The flow control apparatus according to claim 1 , wherein
in response to the change to the new target flow when the flow regulating valve is closed, the output unit outputs the signal to cause the driving circuit to apply a voltage change rising in a step-like manner up to the greater amplitude than the target voltage value corresponding to the new target flow after the change, and then outputs the signal to cause the driving circuit to apply the voltage so the voltage converges from the greater amplitude to the target voltage value.

4. A flow control apparatus, comprising:
a detecting unit that detects a flow of a fluid flowing in a flow channel;
a piezoelectric element that is coupled to a valve element configuring a flow regulating valve which opens and closes the flow channel, and that works the valve element to regulate the flow;
a driving circuit that applies a voltage to the piezoelectric element to drive the piezoelectric element;
an accepting unit that accepts a target flow of the fluid; and
a control unit that outputs a signal, corresponding to the voltage applied to the piezoelectric element, to the driving circuit based on a deviation of the target flow accepted by the accepting unit and of the flow detected by the detecting unit, so as to control the flow through the driving circuit and the piezoelectric element, wherein the control unit outputs the signal at a steady state value to produce the target flow when the target flow equals the flow detected by the detecting unit, wherein
the control unit comprises:
a generating unit that generates a signal corresponding to the deviation; and
a compensating unit that compensates the signal generated by the generating unit by a control element to generate the signal, the control element contains a numerical value relating to an electrical characteristic of the piezoelectric element and a constant in accordance with a response characteristic of the piezoelectric element so the signal transiently overshoots the steady state value of the signal before converging at the steady state value in response to a change in the target flow, wherein the signal remains at the steady state value while the flow detected by the detecting unit equals the target flow.

5. The flow control apparatus according to claim 4 , wherein
the control element comprises:
a first transfer function that contains a gain relating to the electrical characteristic of the piezoelectric element; and
a second transfer function that contains a constant in accordance with the response characteristic of the piezoelectric element and contains the gain.

6. The flow control apparatus according to claim 5 , wherein
the first and second transfer functions contain a gain relating to an electrical characteristic of the driving circuit.

7. The flow control apparatus according to claim 5 , wherein
the control element relates to a response from a time when a signal is inputted from the control unit to the driving circuit to a time when the piezoelectric element works the valve element.

8. The flow control apparatus according to claim 5 , wherein
when the flow regulating valve is closed, the control unit makes a voltage applied by the driving circuit to the piezoelectric element become different from a voltage, at which the valve opening degree of the flow regulating valve becomes zero, by a predetermined voltage Vc in a direction where the flow regulating valve is further closed, and
when the target flow accepted by the accepting unit in a case that the flow regulating valve is in a closed condition is changed, the compensating unit compensates a signal in which the Vc is superimposed on the signal generated by the generating unit.

9. The flow control apparatus according to claim 8 , wherein the driving circuit comprises an output unit that outputs a signal, corresponding to the voltage applied to the piezoelectric element, to the control unit,
the signal generating unit is configured to generate a feedback signal in order to regulate the response characteristic of the piezoelectric element based on the signal outputted by the output unit, and
the compensating unit compensates the signal in which the Vc is superimposed on the signal generated by the generating unit and compensates the feedback signal generated by the signal generating unit.

10. The flow control apparatus according to claim 9 , further comprising:
a converting unit that converts a signal corresponding to the Vc, based on the second transfer function, wherein
the signal generating unit generates the feedback signal by the compensation of the signal outputted by the output unit and the signal converted by the converting unit.

11. The flow control apparatus according to claim 8 , further comprising:
a reducing unit that reduces a change of the Vc, wherein
when the target flow accepted by the accepting unit in a case that the flow regulating valve is in a closed condition is changed, the compensating unit compensates a signal in which the Vc reduced by the reducing unit is superimposed on the signal generated by the generating unit.

12. The flow control apparatus according to claim 10 , further comprising:
a reducing unit that reduces a change of the Vc, wherein
the converting unit converts a signal corresponding to the Vc reduced by the reducing unit, and
when the target flow accepted by the accepting unit in a case that the flow regulating valve is in a closed condition is changed, the compensating unit compensates a signal in which the Vc reduced by the reducing unit is superimposed on the signal generated by the generating unit and compensates the feedback signal generated by the signal generating unit.

13. The flow control apparatus according to claim 4 , wherein
the piezoelectric element is a laminated piezoelectric element.

14. The flow control apparatus according to claim 4 , wherein
the flow regulating valve comprises a valve port arranged in the flow channel, and the valve element is a plate-like diaphragm that is capable of being elastically deformed by a pressing force from the piezoelectric element to seat around the valve port.

Assignees

• Hitachi Metals Ltd

Inventors

• Ohtsuki Haruaki
• Sonoda Masashi

Classifications

• G05D7/0617

  specially adapted for fluid materials · CPC title

• F16K7/123

  the seat being formed on the bottom of the fluid line · CPC title

• G05D7/0635 Primary

  by action on throttling means (G05D7/0688, G05D7/0694 take precedence) · CPC title

• F16K31/007 Primary

  Piezoelectric stacks · CPC title