Valve assembly
A valve assembly includes a valve housing defining therein a fluid flow channel between a first end arranged to be connected to a source of pressurised fluid, and an outlet a frangible member disposed within and across the fluid flow channel, rupture means for rupturing the frangible member and biasing means for biasing the means for rupturing into contact with the frangible member to cause rupture thereof. The assembly also includes retaining means for retaining the rupture means out of contact with the frangible member to prevent rupture thereof and release means configured to release the retaining means to allow the biasing means to bias the rupture means into contact with the frangible member. The retaining means includes a bearing extending to engage the biasing means and hold it in a compressed state and the assembly includes also includes securing means for securing the bearing in the engaged state.
1. A valve assembly comprising:
a valve housing defining therein a fluid flow channel between a first end arranged to be connected to a source of pressurised fluid, and an outlet;
a frangible member disposed within and across the fluid flow channel so as to block flow from the first end to the outlet;
rupture means for rupturing the frangible member to allow flow from the first end to the outlet;
biasing means for biasing the means for rupturing into contact with the frangible member to cause rupture thereof;
retaining means for retaining the rupture means out of contact with the frangible member to prevent rupture thereof, wherein the retaining means includes a bearing extending to engage the biasing means and hold it in a compressed state, against its bias;
release means configured to release the retaining means to allow the biasing means to bias the rupture means into contact with the frangible member; and
securing means for securing the bearing in the engaged state;
wherein the release means comprises a trigger attached to the securing means which, when actuated, moves the securing means to release the bearing away from engagement with the biasing means whereby the biasing means expands to bias the rupture means into contact with the frangible member to cause rupture thereof;
wherein the bearing comprises two or more ball bearings mounted in a channel around the housing, the ball bearings extending into the housing to retain the biasing means in a non-biased state;
wherein the release means comprises a basket formed over a part of the housing and extending across at least part of the channel so as to hold the ball bearings in the state where they extend into the housing.
2. The valve assembly of claim 1 , wherein the frangible member comprises a disk or a membrane.
3. The valve assembly of claim 1 , wherein the rupture means comprises a rod axially movable within the housing.
4. The valve assembly of claim 3 , wherein the rod has a pointed end to rupture the frangible member.
5. The valve assembly of claim 1 , wherein the biasing means comprises a spring in contact with the rupture means, biased to expand to bring the rupture means into contact with the frangible member.
6. The valve assembly of claim 1 , wherein the trigger comprises a wire or lanyard attached to the basket to lift the basket such that the ball bearings can move out of engagement with the biasing means so that the biasing means takes up its biased state.
7. The valve assembly of claim 1 , wherein the ball bearings are attached to the basket.
8. The valve assembly of claim 6 , wherein the ball bearings are attached to the basket.
9. The valve assembly of claim 6 , wherein the trigger is fixed to the basket at a plurality of points.