Medical fluid machine having solenoid control system with reduced hold current
First Claim
Patent Images
1. An electromechanical solenoid control system comprising:
- an electromechanical solenoid including an armature and a coil;
a voltage source;
a resistor placed in an electrical line between the voltage source and the solenoid coil;
a switching device configured to selectively apply power from the voltage source to the solenoid coil;
a control element connected electrically to the switching device, the control element operable to receive a continuous signal from the electrical line and use the signal to (i) determine when to switch from a solenoid activation state to a solenoid hold state and (ii) control the switching device to selectively apply power from the voltage source to the solenoid coil; and
wherein the control element is further operable to cause the switching device to (a) operate at a solenoid actuation level when, in the solenoid actuation state, the armature is to be moved within the coil and (b) to operate at a solenoid hold level when, in the solenoid hold state, the continuous signal indicates to the control element that the armature is moving or has moved within the coil.
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Abstract
An electromechanical solenoid control system with reduced hold current includes an electromechanical solenoid including an armature and a coil; a voltage source; a resistor placed in an electrical line between the voltage source and the solenoid coil; a switching device configured to selectively apply power from the voltage source to the solenoid coil; and a control element connected electrically to the switching device, the control element operable to receive a signal from the electrical line and use the signal to control the switching device to selectively apply power from the voltage source to the solenoid coil.
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Citations
27 Claims
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1. An electromechanical solenoid control system comprising:
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an electromechanical solenoid including an armature and a coil; a voltage source; a resistor placed in an electrical line between the voltage source and the solenoid coil; a switching device configured to selectively apply power from the voltage source to the solenoid coil; a control element connected electrically to the switching device, the control element operable to receive a continuous signal from the electrical line and use the signal to (i) determine when to switch from a solenoid activation state to a solenoid hold state and (ii) control the switching device to selectively apply power from the voltage source to the solenoid coil; and wherein the control element is further operable to cause the switching device to (a) operate at a solenoid actuation level when, in the solenoid actuation state, the armature is to be moved within the coil and (b) to operate at a solenoid hold level when, in the solenoid hold state, the continuous signal indicates to the control element that the armature is moving or has moved within the coil. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An electromechanical solenoid control system comprising:
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an electromechanical solenoid including an armature and a coil; a power source configured to power the coil; and a control element configured to control power from the power supply to the coil, the control element receiving a signal from an electrical point between the power supply and the coil, the signal changing in a characteristic fashion when the armature upon activation begins to move or is moving within the coil, the characteristic change including a negative going current spike in the coil caused when the armature begins to move, the control element configured to sense this characteristic change and to thereafter reduce power from the power source to the coil. - View Dependent Claims (16, 17, 18)
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19. An electromechanical solenoid control system comprising:
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an electromechanical solenoid including an armature and a coil; a power source configured to power the coil; and a control element configured to control power from the power supply to the coil, the control element receiving a signal from an electrical point between the power supply and the coil, the signal changing in a characteristic fashion including a positive-going current spike in the coil when the armature after an intentional release begins to move or is moving within the coil, the control element configured to sense the characteristic change and store the current level at which the change occurred. - View Dependent Claims (20, 21, 22, 23, 24)
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25. An electromechanical solenoid control method comprising:
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intentionally releasing an armature of a solenoid; sensing a power current level at which a positive-going current spike occurs in a coil of the solenoid; updating an electrical current release level to be the sensed current level, which is indicative of the armature of a solenoid beginning to move or moving; and setting an electrical current hold level for the solenoid to be the updated electrical current release level plus an increment. - View Dependent Claims (26)
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27. An electromechanical solenoid control system comprising:
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an electromechanical solenoid including an armature and a coil; a voltage source; a resistor placed in an electrical line between the voltage source and the solenoid coil; a switching device configured to selectively apply power from the voltage source to the solenoid coil; a control element connected electrically to the switching device, the control element operable to receive a continuous signal from the electrical line and use the continuous signal to (i) determine when to switch from a solenoid activation state to a solenoid hold state and (ii) control the switching device to selectively apply power from the voltage source to the solenoid coil; and the control element further operable to monitor the continuous signal and to determine that a solenoid fault condition is present if an expected change in the signal does not occur.
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Specification