摘要:
A press-machined fuel induction pipe 40, a hollow tubular type of fixed core 1 with a flange at its upper end, and a nozzle holder 18 that was press-machined into a slender tubular shape and has an orifice plate equipped with a valve seat at the lower end of the nozzle holder, are connected by welding. The upper inner surface of nozzle holder 18 and the outer surface of fixed core 1 are welded after being press-fit. A movable core 14 and a valve body 16 are connected to the welded assembly via a point 15 having a spring function. On the outer surface of nozzle holder 18 is provided an electromagnetic coil 2, the outside of which is provided with a tubular yoke 4 whose upper end is connected by welding to the flange 1a of fixed core 1 and whose lower end is press-fit on the outer surface of nozzle holder 18.
摘要:
A press-machined fuel induction pipe 40, a hollow tubular type of fixed core 1 with a flange at its upper end, and a nozzle holder 18 that was press-machined into a slender tubular shape and has an orifice plate equipped with a valve seat at the lower end of the nozzle holder, are connected by welding. The upper inner surface of nozzle holder 18 and the outer surface of fixed core 1 are welded after being press-fit. A movable core 14 and a valve body 16 are connected to the welded assembly via a point 15 having a spring function. On the outer surface of nozzle holder 18 is provided an electromagnetic coil 2, the outside of which is provided with a tubular yoke 4 whose upper end is connected by welding to the flange 1a of fixed core 1 and whose lower end is press-fit on the outer surface of nozzle holder 18.
摘要:
A superconducting magnet includes: a superconducting coil for generating a static magnetic field; a refrigerant container for containing the superconducting coil and a refrigerant; a vacuum container for holding the refrigerant container in a vacuum state; a radiation shield between the refrigerant container and the vacuum container; a refrigerator for re-liquidfying the refrigerant; and a dynamic magnetic field shield. The refrigerator includes: first and second regenerative refrigerants. The dynamic magnetic field shield is an electric good conductor and arranged around the first regenerative refrigerant along a motion axis of the first regenerative refrigerant, wherein a direction of the motion axis is aligned with a direction of a magnetic force line of the static magnetic field at the first regenerative refrigerant.
摘要:
In a gradient magnetic field coil device including: a plurality of main coils generating in an imaging region of a magnetic field resonance imaging device a magnetic field distribution in which an intensity linearly inclines; and a plurality of shield coils, arranged on an opposite side of the imaging region across the main coils, suppressing residual magnetic field generated by the main coils on the opposite side. The plurality of main coils and the plurality of shield coils are connected in series. The device further includes a plurality of current adjusting devices, connected to the shield coils in parallel, independently adjusting currents flowing through the shield coils, respectively, to enhance symmetry of the residual magnetic field. The gradient magnetic field coil device is provided which can suppress generation of eddy current magnetic field even if there is a relative position deviation between the main coils and shield coils.
摘要:
The active shield superconducting electromagnet apparatus includes: a main switching circuit in which first and second main coils, first and second shield coils, and a first superconducting persistent current switch are connected in series; a sub switching circuit in which a bypass circuit, in which a superconducting fault current limiter and a second superconducting persistent current switch are connected in series, are connected to a series circuit of the first main coil and the second main coil in parallel; a first closed circuit in which at least one of the first main coil and the first shield coil, and a first quench protection circuit are connected in series; and a second closed circuit in which one of the second main coil and the second shield coil, and a second quench protection circuit are connected in series.
摘要:
On the basis of the magnetic field intensity distribution of a magnetic field space (3), in order to homogenize the distribution, the positions and the volumes of magnetic material shims (such as shim bolts (27)) which have to be arranged on shim trays (17, 18) are first computed on a minute computational grid. Subsequently, from the distributions of the computed positions and volumes of the magnetic material shims, the local maximum values and local minimum values thereof are extracted, and the distribution areas of the volumes of the magnetic material shims with each value as the center are extracted. Then, the volumes of the magnetic materials distributed in the distribution areas are added. Finally, the results of the addition are displayed with the positions of corresponding local maximum values or the positions of corresponding local minimum values.
摘要:
[Object]An object of the present invention is to provide a MRI superconductive magnet enables sharp images representing patients' health states to be produced. [Means for Achieving the Object]A MRI superconductive magnet having a superconductive coil, a liquid vessel of liquid helium used to cool the superconductive coil, a heat shield to accommodate the liquid vessel therein, a vacuum chamber to accommodate the heat shield therein, a load supporting body for supporting the superconductive coil from the vacuum chamber and securing the superconductive coil, a second cold part of a multi-stage refrigerator for cooling a heat exchanger to condense evaporated helium gas, and a first cold part of the multi-stage refrigerator for cooling the heat shield, wherein a magnetic shield is provided from the first cold part of the multi-stage refrigerator to an outer periphery of the second cold part of the multi-stage refrigerator.
摘要:
A magnetic resonance imaging apparatus and the magnet apparatus thereof comprise plural pairs of magnetic field generation sources, arranged face to face with each other, for forming a magnetic field space 3; and magnetic field homogeneity adjusting apparatuses 17 and 18 for providing homogeneity adjustment of the magnetic field formed in the magnetic field space 3. The magnetic field homogeneity adjusting apparatuses 17 and 18 contain a plurality of tapped holes 24 for installing a magnetic field homogeneity adjusting member 26 of smaller volume in a plate-formed tray made of a non-magnetic substance; and a plurality of mounts 25 for installing the magnetic field homogeneity adjusting member 27 of greater volume, these mounts being formed over the area containing a plurality of through-holes for permitting installation of a magnetic field homogeneity adjusting member 26 of smaller volume, whereby major magnetic field adjusting work can be performed independently of minor magnetic field adjusting work.
摘要:
In a gradient magnetic field coil device including: a plurality of main coils generating in an imaging region of a magnetic field resonance imaging device a magnetic field distribution in which an intensity linearly inclines; and a plurality of shield coils, arranged on an opposite side of the imaging region across the main coils, suppressing residual magnetic field generated by the main coils on the opposite side. The plurality of main coils and the plurality of shield coils are connected in series. The device further includes a plurality of current adjusting devices, connected to the shield coils in parallel, independently adjusting currents flowing through the shield coils, respectively, to enhance symmetry of the residual magnetic field. The gradient magnetic field coil device is provided which can suppress generation of eddy current magnetic field even if there is a relative position deviation between the main coils and shield coils.
摘要:
The magnetic field homogeneity adjusting device (20) is characterized by comprising a magnetic field distribution measuring unit (21) for measuring the magnetic field distribution in the magnetic field space, a temperature variation calculating unit (22) for calculating the temperature variation of the ferromagnetic bodies needed to improve the homogeneity of the magnetic field space based on the measured magnetic field distribution, and a temperature control unit (12) for setting a temperature control value of the ferromagnetic bodies according to the calculated temperature variation.