Hittman Corporation

Lewis Fleischmann

Fred Hittman

Glenn A Meyer

A pressure sensor for indicating pressure in the animal or human body, such as intracranial pressure, including a housing, a bellows contained within the housing, a body pressure sensing tambour for placing the bellows in communication with pressure in the body so that the pressure will cause the bellows to move as a function of the pressure, output means, such as a radioactive source and associated shielding, contained within the housing and associated with the bellows for providing an output which is a function of the movement of the bellows, and a receiver, such as a radiation detector, located external to the body to receive the output and provide data indicative of the pressure in the body. The pressure sensor includes means associated with the bellows to enable in vivo calibration of the pressure sensor after implantation by establishing a preselected output condition during calibration. An ambient pressure sensing tambour is associated with the bellows for compensating for ambient pressure variations. The bellows is resilient, made of a material which has essentially 100% memory of position and has particular critical dimensions in order to provide linear movement in response to the range of pressures to be monitored, and to provide a sufficient movement, or deflection, in order to provide a sufficient readout. The bellows has a spring rate which is substantially greater than the spring rate of the pressure sensing and ambient pressure compensating tambours thereby making the pressure sensor essentially insensitive to temperature variations.

Non-invasive, pressure sensor apparatus for communicating pressure

A non-invasive nuclear device for communicating pressure inside a body to the exterior, such as from within the cranium, bladder or vena cava, of an animal or human, the device including a housing having an interior communicating through a conduit of deformable metallic material with a fluid pressure sensing device positioned within the body portion being monitored, the housing being mounted on the body adjacent the body portion being monitored, a shaped mass of radioactive material together with radiation shield means being disposed within the housing interior together with urging means for producing a predetermined shielding relationship between the radioactive mass and the shield means, the radioactive mass being supported on the urging means for guide movement relative to the shield means and the sensed pressure being exerted through a pressure transmitting fluid flowing within the deformable metal conduit against the urging means for modifying the shielding relationship between the radioactive mass and the shield means proportionally with a change in fluid pressure in the body cavity thereby producing a radioactive output from the radioactive mass corresponding to the magnitude of the fluid pressure in the body position being monitored together with an ambient pressure sensing device mounted on the housing for applying ambient pressure through a pressure transmitting fluid to the urging means in opposition to the sensed body cavity pressure to compensate for changes in ambient pressure.

Non-invasive nuclear device for communicating pressure inside a body to

A pressure sensor apparatus primarily for sensing pressure in a body cavity such as the cranium, bladder or vena cava of an animal or human comprising a housing having non-radioactive fluids contained in two spaced apart regions of the housing. A radioactive fluid immiscible with at least one of the non-radioactive fluids is also contained within the housing between the non-radioactive fluids. The interface between the radioactive fluid and one of the non-radioactive fluids is optionally formed by a resilient member such as an elastomeric diaphragm. A flexible member is connected to the housing and communicates with one of the two spaced apart regions in the housing. The other spaced apart region in the housing is closed by a resilient member such as a metallic diaphragm. With this arrangement, the movement of the radioactive fluid is proportional to the pressure sensed by the flexible member and is sensed by a radiation detector.

Pressure sensor apparatus

A pressure sensor apparatus primarily for sensing pressure in a body cavity such as the cranium, bladder or vena cava of an animal or human comprising a Bourdon or bellows type pressure gauge connected to a flexible member such as a metallic disc or corrugated bellows tambour containing a non-radioactive fluid. A discrete mass of radioactive material is connected to the pressure gauge and moves proportionally to the pressure sensed by the flexible member. A radiation detector senses the movement of the radioactive material through a window in a radiation shield.

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Randallstown, MD, United States of America

Lewis Fleischmann