Valves

Claim 2

A valve having a closable passage for conveying fluid therethrough, and comprising a valve body having an annular bore and a valve spindle formed from a chemically inert polymer slidably located in said annular bore, the spindle having a closure portion comprising a portion of the outer surface of the spindle which is arranged to close said passage, and sealing means for providing a seal between the spindle and the annular bore, the sealing means comprising a radially deformable outer annular segment of the spindle, distending means within said annular segment for adjustably distending it radially outwards to contact the bore wall and form a seal, said closure portion and said annular segment being relatively positioned such that said closure portion is isolated from the distending means by said seal so as to prevent contamination of said distenDing means by the fluid, and adjustment means comprising compression means located axially on both sides of the distending means, and a mandrel interconnecting the compression means whereby the distance between the compression means is adjustable for applying an axial compression to the distending means and effecting a consequential radial distension.

Claim 3

A valve spindle of a chemical inert polymer slidably located in an annular bore in a valve body according to claim 1, said valve body having a valve seat, said spindle having a solid nose portion at one end thereof engaging said valve seat in said valve body to prevent passage of a fluid medium through said valve seat when the valve is closed, and sealing means providing a gland seal between said spindle and the annular bore of said valve body, said sealing means comprising a radially deformable outer annular segment of said spindle, a hollow portion within said spindle having an opening only at the end of said spindle remote from said nose portion, distending means within at least part of said hollow portion of said spindle for distending said outer annular segment radially outwards to contact said annular bore wall of said valve body to form a gland seal, said outer annular segment being positioned in said bore between the fluid medium to be sealed by the gland seal and the opening of said spindle so that said outer annular segment prevents said fluid medium from entering said opening so that the said fluid medium does not contact said distending means, and adjusting means comprising a mandrel and an adjustable sleeve engaging with said mandrel, said distending means being distendable by movement of said sleeve whereby adjustment of said sleeve with respect to said mandrel towards said distending means effects axial compression, and consequential radial distension of said distending means, said adjusting means being adjustably operable through said spindle opening so that it is adjustable from outside of said spindle without disturbing the effectiveness of the operating gland seal.

Claim 4

A valve spindle according to claim 2 in which the distending means comprises a length of elastomeric tubing which is coaxially mounted on the mandrel.

Claim 5

A valve spindle according to claim 2 in which the mandrel is provided with an integral enlargement, the distending means being located between said enlargement and the adjustable sleeve.

Claim 6

A valve spindle according to claim 2 in which one end of the mandrel has engagement means which engage with the nose portion whereby rotation of the mandrel with respect to said nose portion during adjustment of the adjustable sleeve is prevented.

Claim 7

A valve spindle according to claim 5 in which the engagement means comprises a screw thread which engages with a corresponding screw thread in the nose portion.

Claim 8

A valve spindle according to claim 2 in which the chemically inert polymer is a fluorine-containing polymer.

Claim 9

A valve spindle according to claim 7 in which the fluorine-containing polymer contains a polytetrafluoroethylene.

Claim 10

A valve according to claim 1 comprising a valve spindle of a chemically inert polymer slidably located in an annular bore of a valve body having a plurality of radially disposed ports communicating with the bore, said spindle having a sealing means comprising a radially deformable outer annular segment of said spindle encompassing a hollow portion having an opening at at least one end, resilient distending means within at least part of said hollow portion of the spindle for resiliently distending said annular segment radially outwards to contact the annular bore wall of the valve body and form a seal, and adjustment means comprising compression means located axially on both sides of the distending means, and a mandrel interconnecting the compression means whereby the distance between the compression means is adjustable for applying an axial compression to the distending means and eFfecting a consequential radial distension, said adjustment means being adjustably operable from outside said spindle without disturbing the effectiveness of the operating seal, said outer annular segment having at least two identations disposed to provide independent fluid flow-passages for inter-connecting selected ports.

Claim 11

A valve according to claim 9 in which the resilient distending means comprises a length of elastomeric tubing which is co-axially mounted on the mandrel.

Claim 12

A valve according to claim 9 in which the mandrel is provided with an integral enlargement, the distending means being located between said enlargement and the adjustable compression member.

Claim 13

A valve according to claim 9 in which the compression member comprising a sleeve co-axially engaging the mandrel by means of screw threads.

Claim 14

A valve according to claim 9 in which a compression spring is co-axially mounted on the mandrel, whereby the compressive force axially compressing the distending means is applied through said spring.

Claim 15

A valve according to claim 9 in which the valve body has a plurality of ports disposed both along and around the body, the surface of the radially deformable annular segment having a plurality of indentations, each capable of being aligned with two or more of the ports simultaneously.

Claim 16

A valve according to claim 14 having at least two banks radially disposed ports, each bank comprising at least two of said ports, and the surface of the annular segment of the spindle being provided with indentations disposed to provide flow passages for inter-connecting selected ports of the same bank, the indentations associated with any one bank of ports being separated from the indentations associated with any other bank of ports by the outer surface of the segment forming a seal in the bore between the banks of ports.

Claim 17

A valve according to claim 14 in which the valve body has at least four transverse planes spaced along said body, each plane containing one or more ports.

Claim 18

A valve according to claim 14 in which the indentations comprise channels arranged to take the shortest path between two ports interconnected thereby.

Claim 19

A valve according to claim 9 in which the pliable outer layer is formed from a fluorine-containing polymer.

Claim 20

A valve according to claim 18 in which the fluorine-containing polymer is polytetrafluoroethylene.