Splitter Valve
A splitter valve comprising an outer sleeve and an inner sleeve both having orifices. The relative position of these elements determines the split of the flow. The orifices are configured so that the relative split between the two streams has a linear relationship with the relative position of the inner element and outer sleeve. A perforate plate is provided across at least one outlet to laminarise the flow.
1 . A splitter valve for splitting an inlet stream into a plurality of outlet streams, the valve comprising an inlet; a plurality of outlets, one for each outlet stream; an outer sleeve having a plurality of first outlet orifices, one for each stream; an inner element moveably retained within the outer sleeve and having an inlet and a plurality of second outlet orifices, one for each stream; wherein the relative proportion of the inlet stream fed to each outlet is determined by the relative position of the inner element and outer sleeve, and wherein the first and second outlet orifices are shaped such that the flow through each outlet varies substantially linearly with the relative position of the inner element and outer sleeve; characterised in that a perforate member is provided across at least one outlet to at least partially laminarise the flow leaving the outlet.
2 . A valve according to claim 1 , wherein the member is a plate.
3 . A valve according to claim 1 , wherein the member is a block.
4 . A claim according to claim 1 , wherein the member is concave.
5 . A splitter valve for splitting an inlet stream into a plurality of outlet streams, the valve comprising an inlet; a plurality of outlets, one for each outlet stream; an outer sleeve having a plurality of first outlet orifices, one for each stream; an inner element moveably retained within the outer sleeve and having an inlet and a plurality of second outlet orifices, one for each stream; wherein the relative proportion of the inlet stream fed to each outlet is determined by the relative position of the inner element and outer sleeve, and wherein the first and second outlet orifices are shaped such that the flow through each outlet varies substantially linearly with the relative position of the inner element and outer sleeve; characterised in that a ramp surface is provided within the inner element at the end furthest from the inlet to direct the inlet stream towards the outlet furthest from the inlet.
6 . A splitter valve according to claim 1 , wherein a perforate plate is provided across at least one outlet to at least partially laminarise the flow leaving the outlet.
7 . A splitter valve for splitting an inlet stream into a plurality of outlet streams, the valve comprising an inlet; a plurality of outlets, one for each outlet stream; an outer sleeve having a plurality of first outlet orifices, one for each stream; an inner element moveably retained within the outer sleeve and having an inlet and a plurality of second outlet orifices, one for each stream; wherein the relative proportion of the inlet stream fed to each outlet is determined by the relative position of the inner element and outer sleeve, and wherein the first and second outlet orifices are shaped such that the flow through each outlet varies substantially linearly with the relative position of the inner element and outer sleeve; characterised in that at least one of the outlet orifices has a shape which extends in a circumferential direction and is tapered along at least a portion of its length, wherein the tapering portion subtends an angle of at least 30° at the centre of the valve.
8 . A splitter valve according to claim 7 , wherein the tapering portions subtends an angle of at least 40° at the centre of the valve.
9 . A valve according to claim 8 , wherein the tapering portions subtends an angle of at least 45° at the centre of the valve.
10 . A valve according to claim 7 , wherein a first outlet orifice has a shape which extends in a circumferential direction and is tapered along at least a portion of its length; a second outlet orifice has a shape which extends in a circumferential direction and is tapered along at least a portion of its length, wherein the two orifices taper in opposite circumferential directions, and wherein the circumferential overlap between the first and second outlet orifices subtends an angle of at least 40° at the centre of the valve.
11 . A valve according to claim 10 , wherein the circumferential overlap between the first and second outlet orifices subtends an angle of at least 50° at the centre of the valve.
12 . A valve according to claim 11 , wherein the circumferential overlap between the first and second outlet orifices subtends an angle of at least 60° at the centre of the valve.
13 . A splitter valve for splitting an inlet stream into a plurality of outlet streams, the valve comprising an inlet; a plurality of outlets, one for each outlet stream; an outer sleeve having a plurality of first outlet orifices, one for each stream; an inner element moveably retained within the outer sleeve and having an inlet and a plurality of second outlet orifices, one for each stream; wherein the relative proportion of the inlet stream fed to each outlet is determined by the relative position of the inner element and outer sleeve, and wherein the first and second outlet orifices are shaped such that the flow through each outlet varies substantially linearly with the relative position of the inner element and outer sleeve; characterised in that a first outlet orifice has a shape which extends in a circumferential direction and is tapered along at least a portion of its length; a second outlet orifice has a shape which extends in a circumferential direction and is tapered along at least a portion of its length, wherein the two orifices taper in opposite circumferential directions, and wherein the circumferential overlap between the first and second outlet orifices subtends an angle of at least 40° at the centre of the valve.
14 . A valve according to claim 13 , wherein the circumferential overlap between the first and second outlet orifice subtends an angle of at least 50° at the centre of the valve.
15 . A valve according to claim 14 , wherein the circumferential overlap between the first and second outlet orifices subtends an angle of at least 60° at the centre of the valve.
16 . A splitter valve for splitting an inlet stream into a plurality of outlet streams, the valve comprising an inlet; a plurality of outlets, one for each outlet stream; an outer sleeve having a plurality of first outlet orifices, one for each stream; an inner element moveably retained within the outer sleeve and having an inlet and a plurality of second outlet orifices, one for each stream; wherein the relative proportion of the inlet stream fed to each outlet is determined by the relative position of the inner element and outer sleeve, and wherein the first and second outlet orifices are shaped such that the flow through each outlet varies substantially linearly with the relative position of the inner element and outer sleeve; characterised in that at least one of the outlet orifices has tapered portion, the taper having a concave profile.
17 . A valve according to claim 16 , wherein the tapered portion has a profile in which the half width, being the axial distance from a circumferential line passing through the centre of the orifice to the edge of the orifice, has a third order polynomial shape.
18 . A valve according to claim 17 , wherein the third order polynomial is defined as:
Half-width %(0.5*θ 2 )+(0.5*θ 3 )
where θ is the angle of rotation of the valve.
19 . A splitter valve for splitting an inlet stream into a plurality of outlet streams, the valve comprising an inlet; a plurality of outlets, one for each outlet stream; an outer sleeve having a plurality of first outlet orifices, one for each stream; an inner element moveably retained within the outer sleeve and having an inlet and a plurality of second outlet orifices, one for each stream; wherein the relative proportion of the inlet stream fed to each outlet is determined by the relative position of the inner element and outer sleeve, and wherein the first and second outlet orifices are shaped such that the flow through each outlet varies substantially linearly with the relative position of the inner element and outer sleeve; characterised in that for each outlet a bleed hole is provided in the inner element and is positioned so that there is flow through each outlet in all positions of the inner element.
20 . A splitter valve for splitting an inlet stream into a plurality of outlet streams, the valve comprising an inlet; a plurality of outlets, one for each outlet stream; an outer sleeve having a plurality of first outlet orifices, one for each stream; an inner element moveably retained within the outer sleeve and having an inlet and a plurality of second outlet orifices, one for each stream; wherein the relative proportion of the inlet stream fed to each outlet is determined by the relative position of the inner element and outer sleeve, and wherein the first and second outlet orifices are shaped such that the flow through each outlet varies substantially linearly with the relative position of the inner element and outer sleeve; characterised in that each first outlet orifice is provided with an annular seal, these seals being fitted into the outlet orifice so that its outer periphery seals against the inner periphery of the outlet orifice and the radially inner surface of the seal seals against the inner element.