Valves and valve actuation – Permanent or constantly energized magnet actuator
Reexamination Certificate
2000-09-29
2002-08-27
Doerrler, William C. (Department: 3754)
Valves and valve actuation
Permanent or constantly energized magnet actuator
C251S176000, C251S177000, C251S228000, C251S233000, C251S234000, C251S237000
Reexamination Certificate
active
06439538
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pressure variable valve apparatus, more particularly to a pressure variable valve apparatus suitable for being used as a shunt valve embedded in the body for adjusting pressure of the cerebrospinal fluid or the like and a set pressure detecting apparatus thereof.
2. Description of the Prior Art
Japanese Patent Laid-Open No. 40063/1985 discloses a shunt valve construction in which there is provided in a flow path of the cerebrospinal fluid or the like for adjusting the pressure of the cerebrospinal fluid or the like, a shunt valve provided with a leaf-like spring one end portion of which is brought into contact with a ball serving as a valve element, the other end portion of which is engaged with a cam face in a shape of a spiral staircase integrally formed with a rotor of a multiple pole step motor element and which changes the pressing force on the ball by the spring by changing a flexing amount of the spring by moving the engaged end portion of the spring in an axial direction of the rotor in accordance with the rotation of the cam face in correspondence with rotation of the rotor for treatment of hydrocephalus or the like. A pressure variable valve apparatus of this kind is known as the “MEDOS (trademark) pressure variable type valve shunt system” and constructed such that a fixed marker referred to as white marker is provided in a main body and a movable marker is referred to as pressure indicator is provided integrally with the cam to be able to confirm the set pressure of the valve apparatus when embedded in the human body and the position of the white marker and rotational position of the pressure indicator can be detected by an X ray apparatus.
However, it is not preferable for health to irradiate the human body with X ray to thereby expose the human body to X ray every time of confirming a set pressure state of the valve apparatus.
Further, there is known in, for example, Japanese Patent Laid-Open No. 170749/1996, a valve apparatus in which one end portion of a leaf spring bent substantially in a semicircular shape is fixed to a rotor, a peripheral face of a middle portion of the leaf spring bent and extended in the semicircular shape from the fixed end portion to a free end is made to be able to be brought into contact with a valve element in a ball-like shape and press force of the ball by the spring is changed in accordance with a change in a position of bringing the spring into contact with the ball in accordance with a change in rotational angle of the rotor. The valve apparatus of this kind is known as “SOPHY valve system” and according to the valve apparatus, the rotor is formed by a permanent magnet magnetized in one diameter direction, a compass (rotatable magnetic needle) is mounted on the surface of the body at a portion embedded with the valve apparatus and the rotational angle of the permanent magnet of the rotor is detected by a direction of the magnetic needle of the compass.
However, such a constitution capable of detecting the rotational angle by such a simple means by and large, is limited to a special valve apparatus in which the set pressure can be adjusted by rotating the rotor comprising the single.(two-poled) permanent magnet in a range of angle smaller than 360 degree. According to the valve apparatus, with regard to the rotor having a magnetically simple structure comprising the two-poled permanent magnet, the rotational angle of the rotor is adjusted in the range smaller than one rotation and therefore, the constitution is not suited to the rotational position control by the step motor structure, the magnet is arranged at the surface of the body embedded with the valve apparatus and the magnet per se outside of the body is rotated to thereby directly control position of the rotor and various disadvantages are accompanied such that the rotor per se is obliged to enlarge to some degree in order to enable such position control and the like. Further, when rotational center of the compass is shifted relative to the rotational center of the rotor, there also is a concern that an indicator of the compass does not accurately represent the set pressure.
The invention has been carried out in view of the above-described points and it is an object thereof to provide a pressure variable valve apparatus capable of accurately detecting set pressure and a set pressure detecting apparatus of the valve apparatus without being injurious to health.
SUMMARY OF THE INVENTION
According to an aspect of the invention, there is provided a pressure variable valve apparatus which is a valve apparatus constituted to be embedded in the body and having a variable set pressure, the pressure variable valve apparatus comprising a movable member linearly movable in a main body to change a pressure for releasing closure of a valve flow path by a valve element, a fixed magnetic marker mounted stationally to the main body, and a movable magnetic marker integrally formed with the movable member. Meanwhile, according to another aspect of the present invention, there is provided a set pressure detecting apparatus of a pressure variable valve apparatus, the set pressure detecting apparatus comprising a magnetic sensor, and a supporter for supporting the magnetic sensor outside of the body scannably in a direction of moving the movable magnetic marker to provide from the magnetic sensor a detection output in accordance with positions of the fixed magnetic marker and the movable magnetic marker of the valve apparatus.
According to the pressure variable valve apparatus, the fixed magnetic marker indicating a reference position is mounted stationarily to the main body, the movable or moving magnetic marker is formed integrally with the movable member and accordingly, by detecting the positions of the two markers by the magnetic sensor, movement of the movable member can be detected by detecting movement of the movable magnetic marker relative to the fixed magnetic marker. Further, the movable member formed with the movable magnetic marker can be moved linearly relative to the fixed magnetic marker or the main body and accordingly, an amount of moving the movable member can be detected by detecting a distance between the two markers or an amount of changing the distance along the direction of moving the movable member. Further, the movable member is constituted to change the set pressure (pressure for releasing closure of the valve path by the valve element) by the linear movement and accordingly, by detecting the amount of moving the movable member, the set pressure of the valve apparatus can be detected. In the detecting operation, X ray irradiation or the like is not needed and there is no concern of being injurious to health.
Further, according to the set pressure detecting apparatus of the invention, the magnetic sensor is supported outside of the body by the supporter scannably in the direction of moving the movable magnetic maker to provide the detection output in accordance with the positions of the fixed magnetic marker and the variable magnetic marker of the pressure variable valve apparatus from the magnetic sensor and accordingly, the positions of the two markers can be detected firmly and accurately by the magnetic sensor. Further, in the case in which the movable member is made movable in the linear direction, so far as the valve apparatus is embedded at a site proximate to the surface of the body, the direction of moving the movable member in the valve apparatus can optically be recognized as an outer shape of the valve main body even from outside of the body and therefore, setting of the direction can be carried out easily and accurately. The linear moving direction of the movable member is typically selected to actually coincide with a direction of extending a flow path of a fluid in the body such as the cerebrospinal fluid at the portion of embedding the valve apparatus. However, when desired, the valve apparatus may be arranged slenderly in a direction intersecting with the flow pa
Adams & Wilks
Bonderer David A
Seiko Instruments Inc.
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