Valve arrangement,especially for use in anaesthetic gas supply systems

Claim 2

A blow-off valve arrangement for use in a gas circulation system venting to its environment in dependence on the internal pressure prevailing in the system, comprising a valve housing provided with a valve seat, a valve closing member, disposed on said seat from the side of the environment and arranged to be biased in a closing position against said seat so long as said internal pressure is lower than a first predetermined overpressure value and to pass into an open position under the influence of said internal pressure when said internal pressure exceeds said first predetermined value; a movable member exposed to said internal pressure and force transfer means disposed between said movable member and said valve closing member and arranged to mechanically act to close said valve closing member when said internal pressure exceeds a second predetermined overpressure value which is higher than said first predetermined overpressure, whereby said gas circulation system vents to its environment for releasing surplus gas only when its internal pressure equals such an overpressuRe whose value lies between said two predetermined values.

Claim 3

A blow-off valve arrangement according to claim 1, wherein said force transfer means includes means exerting a force opposing the closing of said valve closing member, said opposing force being greater than said first predetermined value, but smaller than said second predetermined value.

Claim 4

A blow-off valve arrangement according to claim 9 wherein said force transfer means includes a magnet which is adapted to attract an armature disposed on said lever of said force transfer means.

Claim 5

A blow-off valve arrangement according to claim 3, wherein the magnet is disposed on the opposite side of the load arm of the lever, and wherein the armature is provided on the load arm.

Claim 6

A blow-off valve arrangement according to claim 4, wherein the magnet is disposed on the same side of the force arm of the lever as the movable member, and wherein the armature is provided on the force arm.

Claim 7

A blow-off valve arrangement according to claim 3 wherein the distance between said magnet and said armature is adjustable.

Claim 8

A blow-off valve arrangement according to claim 9 wherein said force transfer means includes a counterweight provided on said load arm of said double armed lever.

Claim 9

A blow-off valve arrangement according to claim 7, wherein said counterweight is slidable on the load arm of the lever.

Claim 10

A blow-off valve arrangement according to claim 29 wherein said force transfer means includes a double-armed lever, the force arm of which is adapted to be acted upon by said movable member and the load arm of which is adapted to act upon said valve closing member.

Claim 11

A blow-off valve arrangement according to claim 1 wherein the force transfer means comprises a pliable member such as a cord, belt, chain or a resilient strap interconnecting the movable member and the valve closing element, the length of said pliable member exceeding the shortest distance between its fixing points to such an extent that displacement of said movable member has effect on said valve closing member only after said internal pressure has reached said second predetermined value.

Claim 12

A blow-off valve arrangement according to claim 1 wherein the force transfer means comprises a rigid force transfer member interconnecting the movable member and the valve closing element, said rigid member having means for producing lost motion to such an extent, that displacement of said movable member has effect on said valve closing element only after said internal pressure has reached said second predetermined value.

Claim 13

A blow-off valve arrangement according to claim 11, said lost motion is caused by a telescope connection means.

Claim 14

A blow-off valve arrangement according to claim 1 wherein the movable member is a bellows capable of expansion and contraction.

Claim 15

A blow-off valve arrangement according to claim 1, wherein the movable member is a piston which is slidable in a cylinder communicating with the gas system.

Claim 16

A blow-off valve arrangement for use in a re-breathing system for supplying treating gas to a patient, which system includes a re-circulation conduit having a first connection leading to the patient, a second connection for continuously supplying treating gas to the system, a third connection for a compressible bladder, and a one-way valve forcing the gas to flow in a predetermined direction in said conduit, said arrangement comprising a valve housing adapted to be placed directly in the circuit of said re-breathing system and comprising: a valve seat in said valve housing, a cooperating valve closing member disposed on said seat from the side of the environment and arranged to be biased in a closing position against said seat so long as the internal pressure prevailing in the system is lower than a first predetermined overpressure value and to pass into an open position under the influence of said internal pressure when said internal pressure exceeds said first predetermined value; a movable meMber exposed to said internal pressure; and force transfer means disposed between said movable member and said valve closing member and arranged to mechanically act to close said valve closing member when said internal pressure exceeds a second predetermined overpressure value which is higher than said first predetermined overpressure, whereby said gas circulation system vents to its environment for releasing surplus gas only when its internal pressure equals such an overpressure whose value lies between said two predetermined values.

Claim 17

A blow-off valve arrangement for use in a re-breathing system for supplying treating gas to a patient, which system includes a re-circulation conduit having a first connection leading to the patient, a second connection for continuously supplying treating gas to the system, a third connection for a compressible bladder, and a one-way valve forcing the gas to flow in a predetermined direction in said conduit, said arrangement comprising a valve housing adapted to be placed directly in the circuit of said re-breathing system and comprising: a valve seat in said valve housing, a cooperating valve closing member disposed on said seat from the side of the environment and arranged to be biased in a closing position against said seat so long as the internal pressure prevailing in the system is lower than a first predetermined overpressure value and to pass into an open position under the influence of said internal pressure when said internal pressure exceeds said first predetermined value; a movable meMber exposed to said internal pressure; and force transfer means disposed between said movable member and said valve closing member and arranged to mechanically act to close said valve closing member when said internal pressure exceeds a second predetermined overpressure value which is higher than said first predetermined overpressure, whereby said gas circulation system vents to its environment for releasing surplus gas only when its internal pressure equals such an overpressure whose value lies between said two predetermined values.

Claim 18

A blow-off valve arrangement as defined in claim 15, wherein the movable member is disposed opposite said valve seat.

Claim 19

A blow-off valve arrangement as defined in claim 16, wherein the bladder is connected to the recirculation conduit at a location opposite said valve seat.

Claim 20

A blow-off valve arrangement as defined in claim 17, wherein said one-way valve is provided in the recirculation conduit at a location between said valve seat and said bladder, said one-way valve being adapted to prevent the gas-expelled from the bladder from flowing the shortest way to the valve closing element.

Claim 21

A blow-off valve arrangement as defined in claim 18, wherein the bladder and the movable member are disposed near the valve closing element, thereby causing the gas expelled from the bladder upon compression thereof to flow through almost the entire recirculation conduit before reaching the valve closing element.

Claim 22

A blow-off valve arrangement as defined in claim 18 further comprising a throttling means provided in the recirculation conduit between the patient connection and the valve closing element, said throttling means serving to delay the transfer from the bladder to the valve closing element of the pressure surge caused by compression of the bladder.

Claim 23

A blow-off valve arrangement as defined in claim 20, wherein said throttling means comprises a disk provided with a central opening having reduced cross-section.

Claim 24

A blow-off valve arrangement as defined in claim 20, wherein said throttling means comprises a jet or nozzle.

Claim 25

A valve unit for use in a re-breathing system for supplying treating gas to a patient, said unit comprising: a valve housing having an inlet connection; an outlet connection; a bladder connection; a blow-off valve comprising a valve seat and a cooperating valve closing element arranged to keep the blow-off valve closed whenever the pressure acting on the closing element from the interior of the valve housing is lower than a first overpressure value; a connection to a movable member which is capable of expansion and contraction in response to pressure variations within the valve housing; a double armed lever including a force arm and a load arm the force arm of which is adapted to be acted-upon by the force produced by expansion of the movable member and the load arm of which is adapted to act on said closing element to close the blow-off valve only when the pressure in the valve housing exceeds a second pressure value higher than said first value; a one-way valve dividing the valve housing into two separate chambers for allowing gas to flow only from a first of said chambers, with which the blow-off valve communicates, to the second chamber, into which the bladder connection and the connection to the movable member opens.

Claim 26

A valve unit for use in a re-breathing system for supplying treating gas to a patient, said unit comprising: a valve housing having an inlet connection; an outlet connection; a bladder connection; a blow-off valve comprising a valve seat and a cooperating valve closing element arranged to keep the blow-off valve closed whenever the pressure acting on the closing element from the interior of the valve housing is lower than a first overpressure value; a connection to a movable member which is capable of expansion and contraction in response to pressure variations within the valve housing; a double armed lever including a force arm and a load arm the force arm of which is adapted to be acted-upon by the force produced by expansion of the movable member and the load arm of which is adapted to act on said closing element to close the blow-off valve only when the pressure in the valve housing exceeds a second pressure value higher than said first value; a one-way valve dividing the valve housing into two separate chambers for allowing gas to flow only from a first of said chambers, with which the blow-off valve communicates, to the second chamber, into which the bladder connection and the connection to the movable member opens.

Claim 27

A valve unit according to claim 30, wherein the load arm of said lever is provided with an iron part adapted to be attracted by a magnet disposed on the opposite side of the load arm with respect to the blow-off valve, the attraction force between the magnet and the iron part being such that the load arm does not act upon the closing until the overpressure in the valve housing is higher than said second value.

Claim 28

A valve unit according to claim 30, further comprising a throttling means disposed in the valve housing between the inlet connection and the blow-off valve.

Claim 29

A valve unit according to claim 25, wherein said throttling means is a partition having Opening of reduced cross-section.

Claim 30

A blow-off valve arrangement as defined in claim 1 further comprising means disposed in said valve housing between said valve seat and said movable member for preventing any appreciable flow of gas in a direction from said member toward said valve seat within said valve housing.

Claim 31

A blow-off valve arrangement as defined in claim 1 wherein said force transfer means are constituted by a portion of said movable member and is disposed adjacent said valve closing member so that as the pressure in the gas circulation system increases the force transfer means directly applies the force acting on said surface to said valve closing member.

Claim 32

A blow-off valve arrangement according to claim 1, wherein said movable member is disposed on said housing at the side of said valve seat and connected with said valve closing member through force transfer means in the form of a lever.

Claim 33

A blow-off valve arrangement according to claim 15, further comprising an absorber for removing pollutions such as carbon dioxide.