The EVR valve is a device that enables the treatment of aortic stenosis and paravalvular regurgitation. It is a valve with a unique, low-profile insertion profile and is designed to be positioned deep in the patient’s aorta. In addition, it allows access to patients with a complex anatomy, such as those with iliofemoral vascular disease.
It consists of a magnetic armature member, which is movable for controlling flow through a passageway. The armature has a plurality of radially spaced notches along its peripheral edge. It is also able to seat against a non-magnetic valve seat member.
The armature of the valve is moved to a closed position by a spring, which exerts a preload that is adjusted to determine the flow rate. The spring is usually a preloaded armature spring, a conventional design found in conventional flow regulators. This preload is adjusted to the minimum flow rate at a specified duty cycle. It is possible to change the preload of the armature spring in order to dispense with cumbersome calibration requirements.
The EVR valve has a chamber 82, which is sized to restrict lateral movement of the armature and confined by a central bore 36. This bore serves as a conduit between the EVR chamber 82 and the air inlet 38. A filter assembly, containing an adsorptive material 45, is positioned in the passageway between the air inlet 38 and the atmosphere. The filter assembly consists of a plurality of apertures 42 in the filter cover 28. The air flow from the atmosphere 40 passes through the filter cover and the adsorptive material 45, then is admitted into the air inlet 38.
An anti-permeation filter assembly, which contains a layer of activated charcoal, is positioned inside the filter cover. The evr valve vapor management valve 10 is not currently in operation. When the engine is in operation, fuel vapors from the fuel tank (16) are purged into the intake system (20) of the vehicle. This pressure is then lowered in the control chamber 90 by the manifold vacuum 104. The corresponding vacuum differential is generated in the EVR chamber 82, which matches the vacuum signal generated in the control chamber 90.
The valve also has a bobbin 30, which is a cylindrical shaped piece of material that is made from a non-magnetic nylon-tape material. The bobbin’s central bore 36 serves as an air passageway. The bobbin and the central bore are separated by a filter cover 28, which contains a layer of porous filtering material. The radially-spaced notches in the armature 46 are used to draw in fuel vapors. The vacuum in the chamber 82 is boosted by the magnetic force applied to the armature. This increases the vacuum in the chamber, which helps to keep the armature in the closed position.
The EVR delivery catheter has an 18F outer diameter, which is smaller than the 22F outer diameter for the implantation of a CV. This smaller sheath size helps to reduce the size of the femoral artery and sheath to femoral artery ratio. In addition, the insertion profile of the EVR has been improved, with the result that it has a much more consistent radial forces.