Valve element

Valve element (3, 6, 10), comprising a frame, at least one inlet and at least one outlet, a passage connecting the inlet and outlet, at least one burst disk (13, 35, 63) or equivalent, which, when unbroken, closes the passage from inlet to outlet, and a piston element (15, 36, 65) provided with a piercing element or the like for piercing the burst disk. The piston element (15, 36, 65) is provided with a passage (17, 39, 67) for a pressure medium, said passage extending axially through the piston element from one first side to one second side, which passage leading through the piston forms a part of the passage of the pressure medium after the burst disk (13, 35, 63) has been pierced.

BACKGROUND OF THE INVENTION

The present invention relates to a valve element as defined in the preamble of claim1, which comprises a frame, at least one inlet and at least one outlet, a passage connecting the inlet and outlet and at least one burst disk (rupture disk) or equivalent, which, when unbroken, closes the passage from inlet to outlet, and a piston element provided with a piercing element or the like for piercing the burst disk.

A device corresponding to the subject of the invention is known from specification DE 2635076 A. One of the drawbacks of this solution is that the piercing element is returned by the action of pressure back to its original position, so a piece of the burst disk that may have been detached from it by the piercing action may partially block the passage and thus form an obstacle to the flow of pressure medium. In addition, the piercing element has to go completely through the burst disk in order to produce a hole of the desired size in the disk. If the piercing movement is for some reason incompletely executed, it will not produce a hole of the desired size.

The object of the present invention is to achieve a completely new type of solution that makes it possible to avoid the drawbacks of prior-art devices. The object of the invention is to create a reliable apparatus that can be utilized especially in fire extinguishing applications.

The apparatus of the invention is characterized in that the piston element is provided with a passage for a pressure medium, said passage extending axially through the piston element from one first side to one second side, which passage leading through the piston forms a part of the passage of the pressure medium after the burst disk has been pierced.

The apparatus of the invention is additionally characterized by what is stated in claims2–7.

The solution of the invention has numerous significant advantages. The passage through the piston ensures that the piston will be effectively pressed towards the burst disk after the disk has been pierced even in cases where a higher pressure prevails on the opposite side of the burst disk than on the side of the piston-piercer combination. The solution of the invention is leak-proof and reliable. By making the channel formed through the piston element a part of the passage for the pressure medium, a passage having a constant diameter in all circumstances is achieved.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a diagrammatic representation of a pressure system in which it is possible to utilize valve elements according to the invention. The system comprises at least two parallel-connected pressure sources4,4′, which in the solution represented by the figure consist of four pressure containers4,4′ each. In addition, the system comprises at least one first pressure source1and means for opening a connecting passage from the first pressure source1to a pressure network2, which communicates with a first pressure source4. The means for opening a connecting passage comprise a first valve element10, which is disposed between the first pressure source1and the pressure network2. When the first valve element10is opened, e.g. triggered by a control system7or manually, the pressure in the network2rises. This has the effect of opening second valve elements3, which are disposed at least in the passage5between the first pressure source4and the network2. After the pressure in the network2has risen to a sufficient level, a third valve element6will be opened at a pre-set pressure.

As the pressure In the network2is rising, a passage is opened from a second pressure source1′ to a fourth valve element20. This keeps the connection to the second branch2′ of the pressure network closed until the pressure in the first pressure network2has fallen to a predetermined value. After this, the pressure in the second network2′ rises, with the result that valve elements3connected to at least one second pressure source4′ open a passage5′ into the second pressure network2′. The third valve element6is not opened until the pressure in the second pressure network2′ has reached a predetermined value.

A more detailed view of the first valve element10is presented inFIG. 2. The device comprises a frame11which has an inlet connectable to a pressure source and an outlet connectable to an outgoing line. Provided between the inlet and the outlet is a burst disk13(rupture disk) which, when unbroken, closes the passage from the inlet to the outlet. The device also comprises means for piercing the burst disk13. These means consist of a cylinder-piston combination in which the piston15comprises a piercing element14formed on it, preferably on the side of the piston rod16. The piston15has been arranged to be movable within a cylinder space12between a fist position, where the piercing element14formed on the piston rod16is on the outlet side in relation to the burst disk13, and a second position, where the piercing element extends at least partially to the inlet side in relation to the burst disk13. The piston is provided with at least one bore17extending through the piston15, preferably from the piercing element14to the opposite side of the piston15so that, after the burst disk13has been pierced, a passage is formed from the inlet side to the outlet side. Formed at or near the tip of the piercing element is at least one aperture18extending into the bore17, thus forming a part of the passage for the pressure medium after the burst disk13has been pierced. The cylinder space is preferably provided with a sleeve part110which has an opening extending in the axial direction of the piston, the piston rod being substantially sealedly fitted to move in the opening. The burst disk13is sealedly fitted against the sleeve110and tightened by means of an inlet coupling101. Furthermore, the device comprises actuating means for actuating the piston-piercer combination. The embodiment illustrated inFIG. 2is provided with both a manual actuating element and an automatic actuating element. The manual solution comprises a handwheel106, which, after removal of a cotter107, can be turned to move it axially towards the piston15according to the pitch of the thread108. The axial movement is transmitted by a spacer111to the surface of the piston15facing in the opposite direction relative to the piercing element, thus causing the piercer to move towards the burst disk13. Once the handwheel has been rotated sufficiently, the tip of the piercer will pierce the burst disk, thus allowing the pressure medium to flow through the apertures18and the bore17to the outlet side. The pressure medium is now admitted to the outlet102side of the piston15, where the piston surface is larger than the cross-sectional area of the piston rod, with the result that the piston15is moved by the action of the pressure towards the burst disk until it is stopped by the sleeve110. Thus, even a small hole in the burst disk13is sufficient to cause the piercer14to penetrate the burst disk through an area corresponding to the cross-section of the piercer.

A second actuating element is designed for remote control, whereby the valve element is to be triggered by means of a control signal. The control signal is supplied via transmission means8, such as conductors, typically from a control system. The control signal causes the piston of the actuating element to move towards piston15. In a preferred case, the valve element comprises a connecting piece109placed between the actuating element105and the piston15and provided with bores112or similar relief holes to allow easier passage of the pressure medium from the channel17through the cylinder space12and channel113to the outlet. The actuating element105is preferably an electrically operated device in which a control current detonates an explosive charge in the actuating element, thus causing the piston of the actuating element to be vigorously thrust out. The actuating element can be connected to a control system, so the device can be used e.g. in connection with fire extinguishing equipment so that the impulse triggering the actuating element105is received from fire detectors and/or smoke detectors (not shown).

In the embodiment presented In the figure, the valve element10also comprises a second outlet103especially for venting purposes. To this second outlet it is possible to connect e.g. a valve element (not shown) which, when the valve element is in a state of readiness, vents any leakage pressure but Is closed at high pressures.

There is also a second venting channel104leading out from the cylinder space12to ensure that the piston will be able to move towards the burst disk without being obstructed by the pressure medium between the piston and the burst disk, because the pressure medium can be let out of the space via the second venting channel104.

Thus, the first valve element10is preferably a triggering valve used to trigger a pressure medium system.

After the triggering of the first valve element10, pressure is admitted via the outlet into the first line2. The pressure in the line therefore rises, and the second valve elements3open a passage from the pressure source4into the first line2. The second valve elements3comprise a frame31, a first connection32to line5, a second connection33to the pressure source, a cylinder chamber34and a burst disk35, which is so arranged that, while unbroken, it closes the passage between the first and the second connections. The device also comprises means for piercing the burst disk35. These means consist of a cylinder-piston combination in which the piston36comprises a piercing element37formed on it, preferably on the side of the piston rod38. The piston36has been arranged to be movable in the cylinder space34between a fist position, where the piercing element37formed on the piston rod38is on the side of the first connection32in relation to the burst disk35, and a second position, where the piercing element37extends at least partially to the side of the second connection33in relation to the burst disk35. The piston is provided with at least one bore39extending through the piston, preferably from the piercing element37to the opposite side of the piston so that, after the burst disk35has been pierced, a passage is formed from the side of the second connection to the side of the first connection. Formed at or near the tip of the piercing element is at least one aperture40extending into the bore39, thus forming a part of the passage for the pressure medium after the burst disk35has been pierced, or at least facilitating the admission of the pressure medium into the bore39. As the pressure in the line is increasing, the piston element moves towards the burst disk and the tip of the piercing element penetrates the burst disk. The pressure medium from the pressure source4can propagate via the second connection and through the passage formed by the hole made in the burst disk and the bore in the piston element out via the first connection and line5into line2. The pressure medium is now admitted to the side of the piston36facing towards the first connection, where the piston surface41is larger than the cross-sectional area of the piston rod, with the result that the piston36is moved by the action of the pressure towards the burst disk35until it is stopped by the sleeve42. Thus, even a small hole in the burst disk35is sufficient to cause the piercing element37to penetrate the burst disk through an area corresponding to the cross-section of the piercer. The burst disk and the piercing element and the forces applied to them are so adapted in relation to each other that the burst disk will be at least partially pierced by the piercing element at a desired pressure. Thus, the second valve element3is preferably a closing valve of the second pressure source, being opened by a pressure impulse received from the first pressure source.

To raise the pressure in line2to a sufficient level, it can be provided with a third valve element6. This valve element is also provided with a burst disk designed to be pierced, preferably by means of a piston-piercer combination, after the pressure on the inlet side has risen to a sufficient level. The device comprises a frame61and a cylinder space62with an inlet68from line2and an outlet69. Disposed between the inlet and the outlet is at least one burst disk63which, when unbroken, closes the passage between the inlet and the outlet. Fitted in the cylinder space is a piston element65on the inlet side of the burst disk, the piston element being provided with a piercing element64preferably formed on the piston rod66. In the embodiment illustrated inFIG. 4, the burst disk63is sealedly fitted between a coupling part70designed to connect the valve element to the line2and a sleeve71provided in the frame. When the pressure on the inlet side reaches a predetermined value, the piercing element with at least one aperture78will pierce the burst disk, thus opening a passage from the inlet side to the outlet side, preferably through a bore67formed in the piston.

In all the above-described embodiments, the piston rod16,38,66of the piston element is sealedly fitted against the wall of the cylinder space, so that the pressure medium can typically only flow via the passage provided through the piston.

The burst disk is preferably designed to withstand high pressures and pressure differences. The active pressures are typically over 30 bar, preferably over 70 bar. The pressures may even be as high as 300 bar. The burst disk preferably comprises a thinner part in the area to which the action of the piercing element is applied In the triggering situation.

Valve elements according to the invention can be applied especially in connection with fire extinguishing systems, especially in connection with a fire extinguishing apparatus using high-pressure water mist. The pressure medium may consist of gas, liquid or a mixture of gas and liquid.

It is obvious to the person skilled In the art that the invention is not limited to the embodiments described above, but that it may be varied within the scope of the claims presented below.