Proportional Valve, Electric Shower Incorporating the Proportional Valve and Tap Incorporating Same

A proportional valve comprising:

• an input port and an output port;
• a diaphragm provided between the input port and the output port
• a diaphragm plate mounted to the diaphragm, the diaphragm plate having a pilot orifice formed therethrough;
• a solenoid comprising an armature and a field winding, the armature being movable in a first direction in response to a magnetic field generated by the field winding;
• biassing means arranged to provide a biassing force to the armature in a direction opposite to said first direction, wherein in the absence of current in the solenoid, the biassing force is arranged to urge the armature to position the diaphragm plate in a main orifice between the input port and the output port to block flow of fluid therebetween, with the armature blocking the pilot orifice,
• wherein movement of the armature in said first direction in response to a magnetic field generated by the field winding opens the pilot orifice to allow fluid to flow therethrough, and allows the diaphragm plate to move out of the main orifice to create a gap therebetween allowing flow of fluid from the input port to the output port,
• and wherein the diaphragm plate and main orifice are configured such that in said movement of one relative to the other, the rate of increase of the gap therebetween changes approximately linearly, at least initially.

A proportional valve comprising:

• an input port and an output port;
• a diaphragm provided between the input port and the output port,
• a diaphragm plate mounted to the diaphragm, the diaphragm plate having a pilot orifice formed therethrough;
• a solenoid comprising an armature and a field winding, the armature being movable in a first direction response to a magnetic field generated by the field winding,
• biassing means arranged to provide a biassing force to the armature in a direction opposite to said first direction, wherein in the absence of current in the solenoid, the biassing force is arranged to urge the armature to position the diaphragm plate in a main orifice between the input port and the output port to block the flow of fluid therebetween, with the armature blocking the pilot orifice,
• wherein movement of the armature in said first direction in response to a magnetic field generated by the field winding opens the pilot orifice to allow fluid to flow therethrough, and allows the diaphragm plate to move out of the main orifice to create a gap therebetween allowing flow of fluid from the input port to the output port,
• wherein said biassing means is arranged to exert a variable force on the armature over at least part of its travel.