Abstract: In a superconducting magnet arrangement, such as used in a magnetic resonance system, and a power management method therefor, an enhanced economic power mode (EPM) is implemented wherein the compressor operation is controlled by magnet pressure, temperature and time, so as to ensure the readiness of the magnet system for a scanning operation upon exiting the enhanced EPM. A processor implementing the enhanced EPM looks for a signal that indicates that the magnet system is operational and, in the absence of that signal for a predetermined period of time, enters into EPM. Exit from EPM occurs if certain conditions are violated, but then re-entry into EPM is attempted (re-starting EPM), thereby making the magnet system ready for operation again, if and when a patient scan is to be implemented.

Abstract: In a superconducting magnet arrangement, such as used in a magnetic resonance system, and a power management method therefor, an enhanced economic power mode (EPM) is implemented wherein the compressor operation is controlled by magnet pressure, temperature and time, so as to ensure the readiness of the magnet system for a scanning operation upon exiting the enhanced EPM. A processor implementing the enhanced EPM looks for a signal that indicates that the magnet system is operational and, in the absence of that signal for a predetermined period of time, enters into EPM. Exit from EPM occurs if certain conditions are violated, but then re-entry into EPM is attempted (re-starting EPM), thereby making the magnet system ready for operation again, if and when a patient scan is to be implemented.

Abstract: A valve for controlling cryogen egress from a cryogen vessel has a housing having a low pressure side and a high pressure side with a fluid path defined between. A valve element is interposed between the low pressure side and the high pressure side of the housing. A mechanism is provided for holding the valve element against a valve seat. The mechanism has a cam shaft that is rotatable to displace the valve element from its seat to open the fluid path.

Abstract: A burst disc arrangement for a cryostat comprising a replaceable burst disc (52) held in compression between a high-pressure flange formed at an end of a high-pressure conduit (12), and a low-pressure flange (60) formed at an end of a low-pressure conduit (14). In particular, the burst disc arrangement further comprises: a housing (50) enclosing the high- and low-pressure flanges; and compression means (56), distributed around the housing (50) and being arranged to bear upon the one of the flanges (60), so as to urge it towards the other flange, thereby retaining the burst disc (52) in compression between the flanges. The housing (50) includes a first opening (20) large enough to allow the replaceable burst disc (52) to pass therethrough.

Abstract: A pre-assembled, pre-tested quench path outlet assembly for providing a cryogen egress path from a cryogen vessel. A quench valve (26) is mounted within a flange (28). A cryogen egress tube (32) is sealed in leak-tight manner to the flange, to define a cryogen egress path (40) extending through the cryogen egress tube, the flange and the quench valve. The cryogen egress path is closed by a burst disc (34). In use, the pre-assembled, pre-tested quench path outlet assembly is mounted onto the cryogen vessel such that thermal stratification of gas within the cryogen vessel under normal conditions causes a lower end of the cryogen egress tube to be at a temperature below the freezing points of common air components.

Abstract: The present invention provides a thermal radiation shield (1) for a cryostat, formed of a plastic-metal hybrid material, which comprises a plastic component (23) and a conductive filler material (21) comprising a metal. The thermal radiation shield may be formed by injection moulding.

Abstract: A cryogen vessel (12) connected to a refrigerator chamber (15) arranged to house a cryogenic refrigerator (17). A controlled valve (32) is provided between the cryogen vessel (12) and the refrigerator chamber (15), and may be used to isolate the refrigerator chamber from the cryogen vessel.

Abstract: A valve for controlling cryogen egress from a cryogen vessel has a housing having a low pressure side and a high pressure side with a fluid path defined between. A valve element is interposed between the low pressure side and the high pressure side of the housing. A mechanism is provided for holding the valve element against a valve seat. The mechanism has a cam shaft that is rotatable to displace the valve element from its seat to open the fluid path.

Abstract: A method for controlling egress of gas from a cryogen vessel (12) housing a superconducting magnet (10). A controller (30) receives data indicative of gas pressure within the cryogen vessel; a controlled valve (40) controls the egress of cryogen gas from the cryogen vessel (12); and data is made available to the controller, indicating a state of the magnet. Egress of cryogen gas from the cryogen vessel is controlled by operation of the controlled valve (40) by the controller (30) in response to the available data indicating a state of the magnet.

Abstract: A burst disc replacement apparatus (100) comprises a magazine (122) that carries a first burst disc (232) and a second burst disc (234). A flow path (104) passes through the apparatus (100) for venting fluid. The first burst disc (232) is located in the flow path (104). A translation mechanism (112, 144, 146, 200, 214, 220, 222) is arranged to move the second burst disc (234) into the flow path (104) in place of the first burst disc (232) in response to an indication that fluid pressure at one side of the first burst disc (232) has exceeded a predetermined pressure corresponding to rupture of the first burst disc (232).

Abstract: A burst disc replacement apparatus (102) comprises a magazine (114) carrying a first burst disc (116) and a second burst disc (118). The apparatus also comprises a flow path (104) therethrough for venting fluid. The first burst disc (116) is located in the flow path (104) and the second burst disc (118) is located outside the flow path (104). A translation mechanism is also provided and coupled to the magazine (114) and arranged to permit manual translation of the magazine (114) so that the second burst disc (118) moves, when in use, into the flow path (104) in place of the first burst disc (116).

Abstract: A compressor (1) including a compressor mechanism; an input line (12) for providing gas to the compressor; and an output line (14) for providing compressed gas from the compressor. The compressor may supply gas at a first pressure or at a second pressure, by variation of the charge pressure within a gas circuit. A buffer volume and arrangement of valves, contained within the compressor, facilitate the change in static charge pressure. The electrical power drawn by the compressor is reduced when the charge pressure is reduced. Changing the charge pressure in the compressor also varies the cooling power delivered by the refrigerator. Therefore, this variable charge compressor can be used to reduce the electrical power drawn by an MRI system when it is in standby, and the full refrigeration capability is not required. Also, this has the effect of reducing wear and increasing the life of certain components within the refrigerator and compressor.

Abstract: A magnetic resonance imaging system has a superconducting magnet housed within a cryostat, a cryogenic refrigerator that cools within the cryostat, a helium compressor that supplies compressed helium to the cryogenic refrigerator and to receive a return flow of compressed helium from the refrigerator, and a magnet supervisory system controlling operation of the magnet resonance imaging system. An apparatus is provided for controlling the speed and/or timing of operation of the helium compressor in accordance with predefined algorithms in response to system state data.

Abstract: A magnetic resonance imaging system has a superconducting magnet contained within a cryostat, the cryostat being cooled by a cooling system that includes a healing and compressor, a refrigeration device and a local supervisory system. The helium compressor provides compressed helium to the refrigeration device, and the local supervisory system controls operation of the refrigeration device. The helium compressor is in communication with the local supervisory system, and also is able to communicate, independently of the local supervisory system, with a remote service provider.

Abstract: A burst disc arrangement for a cryostat comprising a replaceable burst disc (52) held in compression between a high-pressure flange formed at an end of a high-pressure conduit (12), and a low-pressure flange (60) formed at an end of a low-pressure conduit (14). In particular, the burst disc arrangement further comprises: a housing (50) enclosing the high- and low-pressure flanges; and compression means (56), distributed around the housing (50) and being arranged to bear upon the one of the flanges (60), so as to urge it towards the other flange, thereby retaining the burst disc (52) in compression between the flanges. The housing (50) includes a first opening (20) large enough to allow the replaceable burst disc (52) to pass therethrough.