Valves and valve actuation – Electrically actuated valve – Remote or follow-up control system for electrical actuator
Reexamination Certificate
2001-05-23
2003-09-16
Mancene, Gene (Department: 3754)
Valves and valve actuation
Electrically actuated valve
Remote or follow-up control system for electrical actuator
C251S129050, C137S625130, C126S0390BA
Reexamination Certificate
active
06619613
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electrically driven gas flow control apparatus in a gas appliance such as, for example, a gas cooking range.
BACKGROUND ART
The conventional gas flow control apparatus of a kind having this type of function employs a geared motor for controlling the flow of gas. However, the conventional gas flow control apparatus employing the geared motor has problems in that it is difficult to accomplish even a slight control, that is, to control the gas flow in a slight quantity. In addition, with the conventional gas flow control apparatus, the flow control characteristic is such that the gas power can be adjustable stepwise, the number of stepwise adjustable positions available being limited. Not only is the number of the available stepwise adjustable positions limited, but also the speed at which the gas power can be adjusted is not controllable, accompanied by such a problem that if the gas power is abruptly adjusted down to a low flame position, the gas flame tends to be extinguished.
The present invention has been devised to substantially eliminate the above discussed problems inherent in the prior art gas flow control apparatus and is intended to provide an improved gas flow control apparatus capable of providing a white-gloved fine adjustment of the gas power. Disclosure of the Invention
To this end, the present invention provides a gas flow control apparatus comprising a gas flow control unit having a gas flow control function of adjusting the flow of gas and a stopping function of selectively initiating and interrupting the supply of gas, a stepping motor for driving the gas flow control unit and a drive control unit for controlling the stepping motor. The gas flow can be adjusted according to the number of pulses applied to the stepping motor, thereby to accomplish the white-gloved fine adjustment.
The gas flow control apparatus is preferably of a structure wherein a variable flow control in which the flow of gas is varied stepwise according to the number of pulses applied to the stepping motor, a flat flow control in which the flow of gas is not varied and a gas interrupting control are performed. This feature makes it possible to allow the gas flow to adjusted finely and in one of a plurality of stepwise gas flows according to the number of pulses applied to the stepping motor.
The gas flow control unit may comprises a slide shutter having an adjusting portion for the flow of gas; a cock body accommodating the slide shutter; a flow control plate having a gas flow adjusting portion; and a drive connecting unit for connecting the slide shutter to the stepping motor, whereby a relative position between the adjusting portion of the slide shutter and the gas flow adjusting portion of the flow control plate is varied by a pulsed drive of the stepping motor to thereby accomplish a gas flow adjustment and interruption. In such case, since a linear sliding motion of the slide shutter suffices, the driving torque required can be reduced as compared with a rotary shutter and, also, the gas interrupting capability when the slide shutter is moved to a closed position can be improved.
The gas flow control apparatus may further comprise a position detecting means for detecting a gas flow control position and wherein the drive control unit includes a position determining means for determining the gas flow control position based on at least a signal from the position detecting means. Even this feature makes it possible to accomplish the gas flow control and interruption.
The drive control unit may be so designed as to ascertain a position based on both the number of pulses applied to the stepping motor to drive the latter and a position determining signal from the position detecting means. According to this feature, since the position of the slide shutter according to the number of pulses applied to the stepping motor and that according to the output from the position detecting means are doubly managed, the accuracy of the gas flow control can be increased to assuredly interrupt the supply of gas to ensure the safety factor.
Preferably, the drive control unit is operable to add a predetermined number of pulses to be applied to the stepping motor to drive the latter to a position determining output of the position detecting means to define a predetermined gas power position, so that a highly accurate gas flow control and interruption can be performed in a simple manner.
In a different aspect of the present invention, there is provided a gas flow control apparatus which comprises a gas flow control unit having a gas flow adjusting capability and a gas closing capability of selectively opening and closing a gas; a stepping motor for driving the gas flow control unit; and a drive control unit for controlling the stepping motor. The drive control unit includes a burner drive determining unit for adjusting a speed of a drive unit from a flow control position of the flow control unit. In this embodiment, at least when a gas flow control valve of the flow control unit is positioned at a position adjacent the minimum flow position, the drive speed is reduced and, therefore, any possible abrupt extinction resulting from an abrupt adjustment to the low flame position can be avoided, allowing the gas flow control apparatus to gain reliability from the user. Also, a red-hot phenomenon which would otherwise result from an abrupt adjustment to the high flame potion can also be avoided and, therefor, no snoot will deposit on a pan, allowing the gas flow control apparatus to gain reliability from the user.
Preferably, the burner drive determining unit is operable to reduce the drive speed when the drive unit is moved to at least a position adjacent a minimum flow position of the flow control unit. In this case, since the gas flow adjusting unit is actuated at a high speed other than at the minimum flow position during the extinction, the extinction can take place quickly. In addition, since the length of time during which the drive unit is driven is reduced, the electricity saving can be achieved and the user can be ensured as to the reliability in operation.
In a further aspect of the present invention, there is provided a gas flow control apparatus which comprises a gas flow control unit having a gas flow adjusting capability and a gas closing capability of selectively opening and closing a gas; a stepping motor for driving the gas flow control unit; and a drive control unit for controlling the stepping motor. The drive control unit is operable to perform a variable speed control by determining a correlation with a flow control position of the flow control unit without an electric power being supplied for a predetermined cycle while the frequency of power supply pulses is fixed, to thereby vary a drive speed. According to this embodiment, the speed can be varied depending on the combustion power and also on the purpose of operation such as, for example, ignition, extinction and a gas power adjustment.
In one aspect of the present invention, there is also provided a gas flow control apparatus which comprises a gas flow control unit having a gas flow adjusting capability and a gas closing capability of selectively opening and closing a gas; a stepping motor for driving the gas flow control unit; and a drive control unit for controlling the stepping motor. The drive control unit includes a voltage determining means, an electricity saving means for performing a duty control according to a level of voltage by fixing the frequency of pulses to be applied to the drive unit according to a level of a power source voltage, a position determining means for determining a correlation with a flow control position of the flow control unit, and a motor speed control means for supplying no electric power for a predetermined cycle by fixing the frequency of the power supply pulses; whereby an electric power to be supplied is leveled by converting the level of the power source voltage into a level of a duty ratio. Accordingly, the level of the power source voltage can
Akamatsu Yoshio
Hatano Kazuyoshi
Kagomoto Yoshiteru
Matsumura Mitsumasa
Murakami Kouichi
Bastianelli John
Greenblum & Bernstein P.L.C.
Mancene Gene
Matsushita Electric - Industrial Co., Ltd.
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