Valve for liquid separation

Abstract

The invention concerns a valve ( 20 ) for liquid separation, especially for analytical or preparative liquid chromatography, with a valve body ( 21 ) that has an inlet ( 31 ) and at least two outlets ( 32, 33 ) connected to it for a flow of liquid. In the valve body ( 21 ), there is a sealing element ( 45 ) consisting of shut-off surfaces to alternately shut off the outlets ( 32, 33 ) with shut-off surfaces ( 48, 49 ) facing away from each other in the shape of a cone segment or spherical segment.

1 - 10 . (canceled)  
   
   
       11 . A valve for liquid separation comprising a valve body having an inlet and at least first and second outlets, a sealing element for closing, at different times, flow from the inlet to the first outlet and from the inlet to the second outlet, the sealing element including first and second shut-off surfaces for respectively shutting off the first and second outlets, both of the first and second shut-off surfaces including an arcuate segment, the first and second shut-off surfaces being arranged to face away from each other the valve body having third and fourth shut-off surfaces respectively associated with the first and second outlets, the third and fourth shut-off surfaces respectively being engaged by the first and second sealing surfaces when the first and second sealing surfaces respectively close the first and second outlets at different times, the first and third sealing surfaces being arranged so that when the first outlet is shut off, the first surface rests on the third surface to form an annular seal, the third surface having a step-shaped projection or nose-shaped projection at the annular seal.  
   
   
       12 . A valve for selectively supplying fluid from an inlet port to an outlet port comprising a sealing element, a passage selectively opened and shut between the inlet and outlet ports by the sealing element, the passage and the sealing element being arranged so there is relative longitudinal back and forth movement between them in first and second opposite directions along a longitudinal axis such that when the sealing element is at (a) a first position relative to the passage along the axis the sealing element is disengaged from the passage interior surface to provide a fluid flow path between the inlet and outlet ports, and (b) a second position relative to the passage along the axis the sealing element engages a portion of the passage interior surface to form a seal between the inlet and outlet ports, the sealing element including a tapered peripheral surface extending generally in the direction of the axis, portions of the peripheral surface being sized and arranged for selectively engaging portions of the passage interior surface to form the seal, the tapered sealing surface having cross sections of progressively larger perimeters along the axis such that the cross-section of the sealing element sealing surface closest to the outlet port has the smallest perimeter that is closer to the longitudinal axis than any other cross-section of the sealing element sealing surface, the passage interior surface including a tapered surface having cross sections of progressively larger perimeters along the axis such that the cross-section of the passage interior surface closest to the outlet port has the smallest perimeter that is closer to the longitudinal axis than any other cross-section of the passage interior surface, the passage interior surface including first and second segments that are displaced from each other along the axis so that the first segment is closer to the outlet port than the second segment and the second segment is closer to the inlet port than the first segment, the perimeters of all cross sections of the second segment being greater than the perimeters of all cross sections of the first segment so all of the passage interior surfaces of the first segment are closer to the axis than all the passage interior surfaces of the second segment, the passage interior surface including a lip between adjacent portions of the first and second segments, the length of the lip in a direction at right angles to the axis being substantially less than (a) the distance between the axis and the perimeter of the cross-section of the first segment farthest from the outlet port and (b) the distance between the axis and the perimeter of the cross-section of the second segment closest to the outlet port, the tapered peripheral surface and the passage interior surface being sized, positioned and arranged so that (a) during initial movement of the sealing element from the first position toward the second position a flow path is provided between the inlet and outlet ports between the tapered peripheral surface of the sealing element and the passage interior surface including the first and second segments, and (b) as the sealing element continues to move toward the outlet port the tapered sealing surface of the sealing element engages the lip to form a seal and prevent fluid flow between the inlet and outlet ports, the spacings between the tapered sealing surface and the passage interior surfaces of the first and second segments while the flow path is provided during the initial movement of the sealing element being substantially less than (a) the distance between the axis and the perimeter of the cross-section of the first segment farthest from the outlet port, and (b) the distance between the axis and the perimeter of the cross-section of the second segment closest to the outlet port.  
   
   
       13 . The valve of  claim 12  wherein the sealing element peripheral surface is arcuate and the passage interior surfaces of the first and second segments are frusto-conical.  
   
   
       14 . The valve of  claim 13  wherein the sealing element peripheral surface is a segment of a sphere and cross sections of the passage interior surfaces in planes at right angles to the axis are circular.  
   
   
       15 . The valve of  claim 12  wherein the lip is arranged to deform slightly in response to the sealing element continuing to move from the initial sealed state between the lip and the peripheral surface along the axis toward the outlet port to provide an annular seal having a length in the direction of the axis that increases from the length of the annular seal when initial contact occurs between the sealing element peripheral surface and the lip.  
   
   
       16 . The valve of  claim 12  wherein the valve is arranged for selectively supplying fluid from the inlet port to a second outlet port via a second passage between the inlet port and second outlet port, the sealing element peripheral surface and the interior surface of the second passage being arranged so that a fluid flow path is provided between the inlet port and the second outlet port while the sealing element is at the second position and a seal is provided between the inlet port and the second outlet port while the sealing element is at the second position; the sealing element, the interior surface of the second passage and the interior surface of the second segment being arranged to provide a flow path between the inlet port and a surface of the sealing element for supplying fluid from the inlet port to the surface of the sealing element to provide a fluid pressure for urging the sealing element against the lip while the sealing element is at the second position.  
   
   
       17 . The valve of  claim 16  wherein the second passage is coaxial with the axis and the inlet port is between the second segment and the second outlet port, and further including an actuator for translating the sealing element between the first and second positions, the actuator including a shaft extending in the second passage along the axis, one end of the shaft being connected to the sealing element.  
   
   
       18 . The valve of  claim 16  wherein the second passage includes a section with a continuous taper between the inlet port and the second outlet port, the taper of the second passage being such that the perimeter of the cross-section of the tapered section closest to the inlet port is greater than the perimeter of all other cross-sections of the tapered section and the perimeter of the cross-section of the tapered section closest to the second outlet port is smaller than the perimeter of all other cross-sections of the tapered section, and the portion of the sealing element peripheral surface for forming a seal between the sealing element and the second outlet port is tapered such that when the sealing element seals the second outlet port cross sections of the sealing element peripheral surface closest to the inlet port have greater perimeters than cross sections of the sealing element peripheral surface closest to the second outlet port.  
   
   
       19 . The valve of  claim 18  wherein the continuous taper of the second passage has a frusto-conical shape and the portion of the sealing element sealing surface for forming the seal between the sealing element and the second outlet port has an arcuate shape.  
   
   
       20 . The valve of  claim 19  wherein the continuous taper of the second passage has circular cross sections at right angles to the axis and the portion of the sealing element peripheral surface for forming a seal between the sealing element and the second outlet port is a sector of a sphere.  
   
   
       21 . The valve of  claim 16  wherein the sealing element and the passages are arranged so that as the sealing element translates between the first and second positions fluid flow paths are provided between the inlet port and both outlet ports.  
   
   
       22 . A valve for selectively supplying fluid from an inlet port to an outlet port comprising a sealing element, a passage selectively opened and shut between the inlet and outlet ports by the sealing element, the passage and the sealing element being arranged so there is relative longitudinal back and forth movement between them in first and second opposite directions along a longitudinal axis such that when the sealing element is at (a) a first position relative to the passage along the axis the sealing element is disengaged from the passage interior surface to provide a fluid flow path between the inlet and outlet ports, and (b) a second position relative to the passage along the axis the sealing element engages a portion of the passage interior surface to form a seal between the inlet and outlet ports, the sealing element including a tapered peripheral surface extending generally in the direction of the axis, portions of the peripheral surface being sized and arranged for selectively engaging portions of the passage interior surface to form the seal, the tapered peripheral surface having cross sections of progressively larger perimeters along the axis such that the cross-section of the sealing element sealing surface closest to the outlet port has the smallest perimeter that is closer to the longitudinal axis than any other cross-section of the sealing element sealing surface, the passage interior surface including a tapered surface having cross sections of progressively larger perimeters along the axis such that the cross-section of the passage interior surface closest to the outlet port has the smallest perimeter that is closer to the longitudinal axis than any other cross-section of the passage interior surface, the passage interior surface including a lip, the tapered peripheral surface and the passage interior surface being sized, positioned and arranged so that (a) during initial movement of the sealing element from the first position toward the second position a flow path is provided between the inlet and outlet ports between the tapered peripheral surface of the sealing element and the passage interior surface, the lip being arranged to deform slightly in response to the sealing element continuing to move toward the outlet port from the initial sealed state between the lip and the peripheral surface along the axis to provide an annular seal having a length in the direction of the axis that increases from the length of the annular seal when initial contact occurs between the sealing element peripheral surface and the lip.  
   
   
       23 . The valve of  claim 22  wherein the sealing element peripheral surface is arcuate and the passage interior surfaces of the first and second segments are frusto-conical.  
   
   
       24 . The valve of  claim 23  wherein the sealing element peripheral surface is a segment of a sphere and cross sections of the passage interior surfaces in planes at right angles to the axis are circular.  
   
   
       25 . The valve of  claim 23  wherein the valve is arranged for selectively supplying fluid from the inlet port to a second outlet port via a second passage between the inlet port and second outlet port, the sealing element peripheral surface and the interior surface of the second passage being arranged so that a fluid flow path is provided between the inlet port and the second outlet port while the sealing element is at the second position and a seal is provided between the inlet port and the second outlet port while the sealing element is at the first position; the sealing element, the interior surface of the second passage and the interior surface of the second segment being arranged to provide a flow path between the inlet port and a surface of the sealing element for supplying fluid from the inlet port to the surface of the sealing element to provide a fluid pressure for urging the sealing element against the lip while the sealing element is at the second position.  
   
   
       26 . The valve of  claim 25  wherein the second passage is coaxial with the axis and the inlet port is between the second segment and the second outlet port, and further including an actuator for translating the sealing element between the first and second positions, the actuator including a shaft extending in the second passage along the axis, one end of the shaft being connected to the sealing element.  
   
   
       27 . The valve of  claim 26  wherein the actuator shaft has circular cross sections at right angles to the axis so that the second passage has annular cross sections.  
   
   
       28 . The valve of  claim 25  wherein the second passage includes a section with a continuous taper between the inlet port and the second outlet port, the taper of the second passage being such that the perimeter of the cross-section of the tapered section closest to the inlet port is greater than the perimeter of all other cross-sections of the tapered section and the perimeter of the cross-section of the tapered section closest to the second outlet port is smaller than the perimeter of all other cross-sections of the tapered section, and the portion of the sealing element peripheral surface for forming a seal between the sealing element and the second outlet port is tapered such that when the sealing element seals the second outlet port cross sections of the sealing element peripheral surface closest to the inlet port have greater perimeters than cross sections of the sealing element peripheral surface closest to the second outlet port.  
   
   
       29 . The valve of  claim 11  wherein the third and fourth shut-off surfaces include material that is softer and more elastic than the first and second shut-off surfaces.  
   
   
       30 . The valve of  claim 29  wherein the third shut-off surface has a step-shaped projection or nose-shaped projection at an annular seal between the first and third surfaces when the first outlet is closed.