Electromagnetic apparatus and method for controlling fluid flow

Abstract

An actuator including actuator base, bobbin, and pole piece forming a pocket for a ferromagnetid armature located therein. The actuator including a radial magnet and a solenoid coil constructed and arranged to cause a linear displacement of the armature upon application of a coil drive current from a control circuit. The actuator may include a flexible membrane that partially encloses the armature to form an armature chamber filled with an incompressible fluid. In a valve design, a fluid flow is stopped by driving the membrane against a valve seat. Pressure from the controlled fluid in the conduit is transmitted through the membrane to the fluid within the armature chamber so that the armature does not need to counteract force applied to the membrane by the conduit fluid's pressure. A fluid flow is opened by driving the membrane away from the valve seat.

1 . An electromagnetic actuator, comprising: 
 a solenoid coil and an armature housing, providing an armature chamber, constructed and arranged to receive a movable armature including a distal part;    a membrane arranged to enclose at least partially said distal part to seal armature fluid inside said armature chamber, said armature being constructed to control flow of fluid through a valve passage by a linear displacement of said distal part caused by a coil drive current applied to said solenoid coil thereby acting on said armature, said displacement of said distal part displaces said membrane with respect to said valve passage controlled by said actuator; and    a radial magnet arranged to maintain said armature in a stationary position by a force of a magnetic field.    
   
   
       2 . The actuator of  claim 1  wherein said distal part of said armature is arranged to compress said membrane against a valve seat when closing said valve passage while said armature is disposed in its extended armature position.  
   
   
       3 . The actuator of  claim 2  further including an armature sensor constructed to detect displacement of said armature.  
   
   
       4 . The actuator of  claim 4  further including a control circuit constructed to apply said coil drive current to said coil in response to an output from said armature sensor.  
   
   
       5 . The actuator of  claim 1  further including a bias spring positioned and arranged to biases said armature toward its extended position.  
   
   
       6 . The actuator of  claim 5  wherein said distal part of the armature is arranged to compress said membrane against a valve seat when closing said valve passage while said armature is disposed in its extended armature position.  
   
   
       7 . The actuator of  claim 5  further including an armature sensor constructed to detect displacement of said armature.  
   
   
       8 . The actuator of  claim 5  further including a control circuit constructed to apply said coil drive current to said coil in response to an output from said armature sensor.  
   
   
       9 . The actuator of  claim 8  wherein said control circuit is operatively connected to receive signals from an external object sensor.  
   
   
       10 . An electromagnetic actuator, comprising: 
 a solenoid coil and an armature housing constructed and arranged to receive in an armature chamber a movable armature including a distal part;    a control circuit constructed to apply a coil drive current to said solenoid coil and thereby cause a linear displacement of said distal part with respect to a valve passage controlled by said actuator; and    a radial magnet arranged to maintain said armature in a stationary position by a force of a magnetic field without application of said coil drive current.    
   
   
       11 . The actuator of  claim 10  wherein said distal part of the armature is arranged to compress a pliable member against a valve seat when closing said valve passage while said armature is disposed in its extended armature position.  
   
   
       12 . The actuator of  claim 11  further including an armature sensor constructed to detect displacement of said armature.  
   
   
       13 . The actuator of  claim 10  wherein said control circuit is powered by a battery.  
   
   
       14 . The actuator of  claim 12  wherein said control circuit is constructed to apply said coil drive to said coil in a first direction to displace said armature to a first end position and being responsive to an output from said sensor meeting a predetermined first current-termination criterion to stop applying coil drive to the coil in the first drive direction.  
   
   
       15 - 23 . (canceled)  
   
   
       24 . The actuator of  claim 10 , wherein said control circuit is operatively connected to an external object sensor.  
   
   
       25 . The actuator of  claim 24  wherein said object sensor includes a motion sensor.  
   
   
       26 . The actuator of  claim 24  wherein said object sensor includes a presence sensor.  
   
   
       27 . The actuator of  claim 24  wherein said object sensor includes an active optical sensor.  
   
   
       28 . The actuator of  claim 24  wherein said object sensor includes a passive optical sensor.  
   
   
       29 . The actuator of  claim 24  wherein said object sensor includes an ultrasonic sensor.  
   
   
       30 . The actuator of claim  20  wherein said object sensor includes a capacitive sensor.  
   
   
       31 . The actuator of  claim 10  further including a pilot body member operatively arranged with said membrane to provide a valve seat for said valve passage.  
   
   
       32 . The actuator of  claim 31  wherein said pilot body member is attached to an actuator base to provide a known, substantially constant distance between an external surface of said membrane and said valve seat.  
   
   
       33 . The actuator of  claim 31  wherein said pilot body member includes a shoulder cooperatively designed with respect to said actuator base to provide a reproducible stop and thereby achieve said known, substantially constant distance when attaching said pilot body member to said actuator base.  
   
   
       34 . The actuator of  claim 1  wherein said radial magnet includes a single ring-like member.  
   
   
       35 . The actuator of  claim 1  wherein said radial magnet includes two or more semicircular members.  
   
   
       36 . The actuator of  claim 1  wherein said radial magnet includes several discrete magnets located radialy with respect to said ferromagnetic armature.  
   
   
       37 . The actuator of  claim 10  wherein said radial magnet includes a single ring-like member.  
   
   
       38 . The actuator of  claim 10  wherein said radial magnet includes two or more semicircular members.  
   
   
       39 . The actuator of  claim 10  wherein said radial magnet includes several discrete magnets located radialy with respect to said ferromagnetic armature.  
   
   
       40 . The actuator of  claim 10  wherein said membrane includes a compliant region, and a resilient region designed to be displaced by said distal part of said armature and designed to come in contact with said valve seat.  
   
   
       41 . A method of controlling a valve passage, comprising the acts of: 
 providing an actuator including an armature and a coil operable by application of a coil drive thereto in a first drive direction to conduct current in a first current direction and thereby tend to drive the armature to a first end position    providing a radial magnet;    applying coil drive to the coil in the first drive direction; and    maintaining said ferromagnetic armature in a stationary position by a force of a magnetic field.    
   
   
       42 . The method of  claim 41  further including determining whether the armature has linearly displaced to reach the first end position using an armature sensor.  
   
   
       43 . The method of  claim 42  wherein said maintaining includes creating a magnetic flux through said armature for creating said force upon said armature.  
   
   
       44 . The method of  claim 43  wherein said force depends on a magnetic flux path outside said armature.  
   
   
       45 . The method of  claim 44  including changing said magnetic flux path outside said armature.  
   
   
       46 - 47 . (canceled)