Valve arrangement to provide temperature level control at cryogenic temperature ranges

Claim 2

A valve arrangement to bleed a cryogenic fluid to an expansion chamber to achieve cooling in the expansion chamber; a hollow valve body having an expansion chamber therein; a cryogen delivery line extending to the expansion chamber, said cryogen delivery line comprising a tube having outwardly directed fins thereon over at least a substantial portion of its length, a housing member, the tubing being disposed in a space between said housing member and said hollow valve body and extending in spiral configuration from one end of said housing to the other end of said housing adjacent said expansion chamber; the end of said delivery liNe being positioned in said expansion chamber and being closed, a pinhole cryogen escape port in the side of said delivery line adjacent the wall of said expansion chamber; a port closure element in operative alignment with said port, said closure element including an arm extending from a pointed tip on the closure element in alignment with the port; means to induce relative movement between the element and the port, and thereby accommodate bleeding flow of the cryogen into the expansion chamber to induce cooling so that the expanding cryogen directly impinges upon the wall of the chamber, the movement induced by said inducing means being responsive to variations in ambient temperature condition of the valve arrangement, said inducing means comprising a sealed bellows carried by the valve arrangement internally of said spiral delivery tube and having a cryogenic fluid disposed therein, said closure element being connected to said bellows; flexure means to bias the bellows and the closure element in a direction to bring the element into closed relationship with the port; another bellows secured to said first-mentioned bellows to seal said connection between said arm and said first bellows and said first mentioned bellows from ambient; the cryogenic fluid in the bellows being adapted to expand in response to a rise in ambient temperature from the predetermined level and induce compression of said flexure means and thereby move the pointed tip of the closure element out of port closing relationship, thereby permitting bleeding flow of the cryogenics fluid.

Claim 3

A valve arrangement for bleeding a cryogenic fluid to an expansion chamber to achieve cooling by means of a Joule-Thomson effect; a hollow outer valve body defining an expansion chamber in one end thereof; an inner hollow support body positioned within said outer body and defining an annular space therearound with the inner surface of said outer body; a cryogen delivery tube disposed in the annular space between said bodies, said cryogen delivery tube comprising a central tube having a plurality of outwardly extending fins over at least a major portion of the length thereof, said cryogen delivery line extending to the expansion chamber within said valve body; a wall of said expansion chamber being thermally connected to a heat load; a fluid escape port in said cryogen delivery line, from which cryogen escapes and expands into the chamber so that the expanded cryogenic fluid impinges on said wall effecting cooling of the heat load; said cryogen delivery line within said expansion chamber being secured with respect to said support body; an orifice closure member in operative alignment with said cryogenic fluid escape port; means to move the port closure member into and out of port closure position to thereby control bleeding flow of the cryogenic fluid into the expansion chamber to induce cooling, said means to move the cryogenic port closure member comprising a sealed bellows carried by the inner body internally thereof and having the same type of cryogenic fluid disposed therein as is being delivered to the expansion chamber, said port closure member being connected to said bellows for movement therewith, spring means carried by the inner body and compressively interposed between the body and the bellows to normally bias the bellows in a direction bringing the port closure member into closed relation with the port; a secondary bellows mounted on the body and accommodating the entrance of the closure member to the first mentioned bellows for connection therewith, said secondary bellows being movable with respect to the closure element and being further adapted to seal the first mentioned bellows from ambient; the cryogenic fluid in the first-mentioned bellows being adapted to expand in response to a rise from ambient temperature from a predetermined level and induce compression of said spring means thereby moving the closure member out of closed relation with the port and accommodating bleeding flow of cryogenic fluid to the chamber.

Claim 4

A valve arrangement for bleeding a cryogenic fluid to an expansion chamber to achieve cooling by means of a Joule-Thomson effect; a hollow outer valve body defining an expansion chamber in one end thereof; an inner hollow support body positioned within said outer body and defining an annular space therearound with the inner surface of said outer body; a cryogen delivery tube disposed in the annular space between said bodies, said cryogen delivery tube comprising a central tube having a plurality of outwardly extending fins over at least a major portion of the length thereof, said cryogen delivery line extending to the expansion chamber within said valve body; a wall of said expansion chamber being thermally connected to a heat load; a fluid escape port in said cryogen delivery line, from which cryogen escapes and expands into the chamber so that the expanded cryogenic fluid impinges on said wall effecting cooling of the heat load; said cryogen delivery line within said expansion chamber being secured with respect to said support body; an orifice closure member in operative alignment with said cryogenic fluid escape port; means to move the port closure member into and out of port closure position to thereby control bleeding flow of the cryogenic fluid into the expansion chamber to induce cooling, said means to move the cryogenic port closure member comprising a sealed bellows carried by the inner body internally thereof and having the same type of cryogenic fluid disposed therein as is being delivered to the expansion chamber, said port closure member being connected to said bellows for movement therewith, spring means carried by the inner body and compressively interposed between the body and the bellows to normally bias the bellows in a direction bringing the port closure member into closed relation with the port; a secondary bellows mounted on the body and accommodating the entrance of the closure member to the first mentioned bellows for connection therewith, said secondary bellows being movable with respect to the closure element and being further adapted to seal the first mentioned bellows from ambient; the cryogenic fluid in the first-mentioned bellows being adapted to expand in response to a rise from ambient temperature from a predetermined level and induce compression of said spring means thereby moving the closure member out of closed relation with the port and accommodating bleeding flow of cryogenic fluid to the chamber.

Claim 5

A temperature control valve mounted in a cryostat comprising an annular space having a spirally wound finned cryogen delivery tube therein, the cryogen delivery tube having an ambient end which is arranged to receive pressurized gaseous cryogen and an outlet end having an opening therein, said cryostat having a wall defining a thermal load, said wall forming one wall of an expansion chamber, said expansion chamber being open to the finned side of said delivery tube so that expanded cryogen passes said delivery tube and cools the cryogen moving therein to the opening, the improvement comprising: a cryogen pressurized bellows positioned within said cryostat, interiorly of said annular space, and in thermal communication with expanded cryogen moving from said expansion chamber past said finned tubing, said bellows having a first end fixed in said cryostat and a second end movable with respect thereto, stop means in said cryostat and on said movable end of said bellows, said stop means being in engagement with each other at temperatures above cryogenic temperature for limiting bellows movement, spring means engaged with said movable end of said bellows urging said stop means apart; said opening in said delivery tube being smaller than the interior bore of said delivery tube and being positioned in the side of said delivery tube and being directed toward said wall in said expansion chamber, said opening forming an expansion orifice for pressurized cryogen, a valve pin positioned to move in throttling relationship with said cryogen expansion orifice, said orifice and said valve pin comprising valve members, one of said valve members being secured to said expansion chamber and the other of said valve members being secured to said movable end of said bellows, said valve members being positioned so that said orifice remains at a fixed throttle opening as the cryostat cools from room temperature substantially down to the cryogenic operating temperature at which temperature said spring moves said movable ends of said bellows away from said stop means to move said valve members together to reduce cryogenic fluid flow out of said orifice opening.

Claim 6

A temperature control valve mounted in a cryostat comprising an annular space having a spirally wound finned cryogen delivery tube therein, the cryogen delivery tube having an ambient end which is arranged to receive pressurized gaseous cryogen and an outlet end having an opening therein, said cryostat having a wall defining a thermal load, said wall forming one wall of an expansion chamber, said expansion chamber being open to the finned side of said delivery tube so that expanded cryogen passes said delivery tube and cools the cryogen moving therein to the opening, the improvement comprising: a cryogen pressurized bellows positioned within said cryostat, interiorly of said annular space, and in thermal communication with expanded cryogen moving from said expansion chamber past said finned tubing, said bellows having a first end fixed in said cryostat and a second end movable with respect thereto, stop means in said cryostat and on said movable end of said bellows, said stop means being in engagement with each other at temperatures above cryogenic temperature for limiting bellows movement, spring means engaged with said movable end of said bellows urging said stop means apart; said opening in said delivery tube being smaller than the interior bore of said delivery tube and being positioned in the side of said delivery tube and being directed toward said wall in said expansion chamber, said opening forming an expansion orifice for pressurized cryogen, a valve pin positioned to move in throttling relationship with said cryogen expansion orifice, said orifice and said valve pin comprising valve members, one of said valve members being secured to said expansion chamber and the other of said valve members being secured to said movable end of said bellows, said valve members being positioned so that said orifice remains at a fixed throttle opening as the cryostat cools from room temperature substantially down to the cryogenic operating temperature at which temperature said spring moves said movable ends of said bellows away from said stop means to move said valve members together to reduce cryogenic fluid flow out of said orifice opening.