Micro-valve
A micro-valve comprises a floating armature, wherein the floating armature is within a fluid flow path through the valve and comprises three or more channels extending along the armature in the direction of fluid flow.
1. A micro-valve configured to dispense amounts of fluid in the range of 1 nl to 1 μl comprising:
a floating armature;
wherein the floating armature is within a fluid flow path through the micro-valve and comprises a fluted section defining three or more channels extending along the floating armature in a direction of fluid flow;
a fixed armature within the flow path of a fluid, which comprises three or more channels corresponding to the channels on the floating armature;
a spring arranged between the floating armature and the fixed armature, radially inwards of the channels on the floating and fixed armatures, at least a portion of the spring being received around a spindle portion of the floating armature, the spindle portion being of a diameter small enough to permit the spring to be at least partially radially recessed relative to the radially-smallest portion of the fluted section of the floating armature;
a housing carrying the floating armature, fixed armature and spring and comprising a head section removably connected to a body section; and
a valve outlet provided in the head section of the housing, wherein the outlet has a diameter of 1.2 mm or less;
wherein the floating armature is configured to move up to 0.5 mm when actuated.
2. A micro-valve according to claim 1 , wherein the three or more channels are arranged to be equidistant around the floating armature.
3. A micro-valve according to claim 1 , wherein the presence of the channels creates three or more lobes on the floating armature.
4. A micro-valve according to claim 1 , wherein the floating armature at least partially tapers in the direction of fluid flow through the micro-valve.
5. A micro-valve according to claim 1 , wherein the floating armature has a maximum radius of 1.5 mm or less.
6. A micro-valve according to claim 1 , wherein the channels have a maximum depth of at least 0.4 mm.
7. A micro-valve according to claim 1 in which:
the housing surrounds at least the floating armature; and
the clearance of the housing from a widest point of the floating armature is 0.100 mm or less.
8. A micro-valve according to claim 1 , further comprising:
an electromagnetic coil for inducing a magnetic field in the floating armature, thereby causing the floating armature to move.
9. A micro-valve according to claim 1 , further comprising:
a valve seat; and
a valve ball;
wherein the valve ball is connected to the floating armature, such that movement of the floating armature opens the micro-valve by withdrawing the valve ball from the valve seat and closes the micro-valve by moving the valve ball into the valve seat.
10. A micro-valve according to claim 1 , wherein the valve outlet is detachable from the micro-valve.
11. A micro-valve according to claim 8 , wherein the floating armature is configured to move up to 0.5 mm when actuated by the electromagnetic coil.
12. A micro-valve according to claim 1 , wherein the channels are parallel to an axis of rotational symmetry of the floating armature.
13. A micro-valve according to claim 1 , wherein the spring acts against a recess on the floating armature, the recess being deeper than the three or more channels.
14. A method of dispensing fluid using the micro-valve according to claim 1 , the micro-valve comprising the floating armature having an axis of rotational symmetry, the floating armature comprising the three or more channels extending in the direction of the axis of rotational symmetry; wherein the method comprises:
operating the micro-valve to dispense fluid such that fluid passes along the channels of the floating armature.
15. A micro-valve according to claim 1 , wherein the floating armature, fixed armature and spring are provided in the body section of the valve housing.
16. A micro-valve according to claim 1 , wherein the spring comprises a stiffness/Hooke's constant in the range of 40-60 mN/mm.
17. A micro-valve according to claim 1 , wherein the spring is configured to impart a force in the range of 0.05 to 0.25 N.
18. A method of dispensing amounts of fluid in the range of 1 nl to 1 μl using a micro-valve, the method comprising:
compressing a spring, arranged between a floating armature and a fixed armature of the micro-valve within a housing, wherein:
the floating armature is within a fluid flow path through the micro-valve and comprises a fluted section defining three or more channels extending along the floating armature in a direction of fluid flow, and
at least a portion of the spring is received around a spindle portion of the floating armature, the spindle portion being of a diameter small enough to permit the spring to be at least partially radially recessed relative to the radially-smallest portion of the fluted section of the floating armature; and
releasing the spring, such that it moves the floating armature, which dispenses fluid through a valve outlet provided in a removable head section of the housing.