The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 12, 1984
Filed:
Sep. 16, 1981
Stephen L Merkel, Bay Village, OH (US);
Richard P Price, Parma Heights, OH (US);
Nordson Corporation, Amherst, OH (US);
Abstract
A solenoid driver circuit for a solenoid-operated fluid dispenser in which a valve is operable to dispense a fluid under the control of the solenoid. The driver circuit receives externally applied turn-on and turn-off signals and energizes the solenoid in response to these signals. The driver circuit is responsive to a turn-on signal to couple a pull-in voltage across the solenoid to pull in a solenoid valve armature. The driver circuit is also operable to sense the level of current in the solenoid. When the solenoid current reaches a preset peak current level, the pull-in voltage is removed from the solenoid and replaced by a hold-in voltage. When the hold-in voltage is applied to the solenoid, the driver circuit is operable to control the level of the hold-in voltage in order to maintain a preselected hold-in current in the solenoid. The driver circuit controls the solenoid current so that it makes a gradual transition from the peak solenoid current level to a steady state hold-in current level. The voltage applied to the solenoid to establish the steady state hold-in current is removed by the driver circuit in response to an externally applied turn-off signal.