Pressure monitoring method and apparatus
First Claim
1. Pressure monitoring apparatus comprising:
- (a) a fluid pressure pump supplying gas under pressure;
(b) a pressure sensor including;
(1) a cup shaped housing having an open mouth and having an inlet and an outlet formed therein;
(2) a flexible diaphragm sealed over the open mouth of the housing to define a plenum between the walls of the mouth in the housing and the diaphragm, and wherein the inlet formed in the housing is in communication with the plenum;
(3) an exhaust tube centrally mounted in the housing within the plenum with an end thereof terminating adjacent the inner side of the diaphragm and connected to be in communication with the outlet from the housing;
(c) tubing connecting the pump to the inlet in the sensor housing to supply gas under pressure to the inlet and also connecting the outlet in the sensor housing to the pump to form a closed system;
(d) a flow restriction connected in the tubing between the pump and the inlet to the sensor housing so that the flow to the sensor is substantially uniform; and
(e) means for measuring pressure connected to measure the pressure in the tubing between the flow restriction and the inlet to the sensor housing, whereby changes in ambient pressure at the pressure sensor will result in movement of the diaphragm to alternately open and close the exhaust tube to automatically maintain the pressure within the plenum approximately equal to the ambient pressure, and whereby the means for measuring pressure in the tubing will measure a pressure which is approximately equal to the pressure within the plenum.
3 Assignments
0 Petitions
Accused Products
Abstract
An apparatus (10) which measures and monitors the pressure within a human body includes a pressure sensor (11) having a housing (30) closed by a pressure sensitive diaphragm (34) to define a plenum (35), an exhaust tube (36) mounted within the plenum (35) which terminates adjacent the inner surface of the diaphragm (34), and tubes (13, 15) which transmit a substantially constant flow of gas into the plenum and which withdraw gas from the exhaust tube (36) to a location remote from the body. Changes in pressure within the body cause the diaphragm (34) to alternately close and open the end of the exhaust tube (36), thereby resulting in an increase or decrease in the pressure within the plenum until an equilibrium pressure is reached. A source (12) of gas pressure is provided, as well as a means for providing a substantially uniform flow rate (R) and means for measuring the pressure (14) within the tube (13) that transmits the gas flow to the sensor (11). The flow rates to and from the sensor (11) are compared, and the flow of gas to the sensor (11) is cut off if the flow rates are unequal, a condition indicative of a leak in the sensor (11) or in the tubing (13, 15, 17) that transmits the gas to and from the sensor.
-
Citations
15 Claims
-
1. Pressure monitoring apparatus comprising:
-
(a) a fluid pressure pump supplying gas under pressure; (b) a pressure sensor including; (1) a cup shaped housing having an open mouth and having an inlet and an outlet formed therein; (2) a flexible diaphragm sealed over the open mouth of the housing to define a plenum between the walls of the mouth in the housing and the diaphragm, and wherein the inlet formed in the housing is in communication with the plenum; (3) an exhaust tube centrally mounted in the housing within the plenum with an end thereof terminating adjacent the inner side of the diaphragm and connected to be in communication with the outlet from the housing; (c) tubing connecting the pump to the inlet in the sensor housing to supply gas under pressure to the inlet and also connecting the outlet in the sensor housing to the pump to form a closed system; (d) a flow restriction connected in the tubing between the pump and the inlet to the sensor housing so that the flow to the sensor is substantially uniform; and (e) means for measuring pressure connected to measure the pressure in the tubing between the flow restriction and the inlet to the sensor housing, whereby changes in ambient pressure at the pressure sensor will result in movement of the diaphragm to alternately open and close the exhaust tube to automatically maintain the pressure within the plenum approximately equal to the ambient pressure, and whereby the means for measuring pressure in the tubing will measure a pressure which is approximately equal to the pressure within the plenum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A pressure sensor adapted for implantation in a human body comprising:
-
(a) a cup-shaped housing formed as a circular plastic disc having a circular open mouth formed in one surface which is surrounded by a peripheral annular face and leaving a top wall at the other surface of the disc; (b) a pressure sensitive diaphragm sealed to the surfaces of the peripheral annular face to close the open mouth of the housing to define a plenum between the diaphragm and the interior walls of the mouth in the housing; (c) an exhaust tube formed integrally with the housing and extending from the top wall of the housing within the center of the plenum to terminate at a position adjacent to the inner side of the diaphragm, the exhaust tube having a circular bore therein; (d) an outlet from the housing including an outlet pipe formed of metal extending through the walls of the exhaust tube into communication with the bore within the exhaust tube and also extending through the walls of the housing to the outside thereof where it is adapted to be connected to external tubing; (e) an inlet for the housing including an inlet pipe formed of metal extending through the wall of the housing from a position outside the housing into the plenum within the housing, the portion of the inlet pipe outside of the housing being adapted to be connected to external tubing, the inlet and outlet pipes being mounted closely adjacent to one another to minimize the space taken up by the pipes and by the tubing to be connected to them, and the inlet and outlet pipes being located at a position in the wall of the sensor housing between the diaphragm and the top wall of the housing such that the thickness of the top wall of the housing can be minimized. - View Dependent Claims (13)
-
-
14. A method of measuring the pressure within a human body comprising the steps of:
-
(a) implanting within a human body a sensor which includes a housing closed by a diaphragm to define a plenum therein and an exhaust tube in the plenum terminating at an end adjacent the inner surface of the diaphragm; (b) providing a first length of tubing which extends from a location outside the human body to the sensor and is in communication with the plenum therein; (c) providing a second length of tubing which extends from a location outside the human body to the sensor and is in communication with the exhaust tube therein; (d) providing gas through the first tubing at a substantially constant flow rate into the plenum in the housing; (e) withdrawing gas through the exhaust tube when the pressure outside the sensor is less than the pressure in the plenum such that the diaphragm is spaced away from the opening to the exhaust tube and transmitting the gas flow through the second tubing, and substantially cutting off the flow of gas into the exhaust tube when the pressure in the plenum is lower than the pressure outside the sensor such that the diaphragm is pressed against the opening of the exhaust tube; (f) measuring the pressure in the first tubing which provides the gas flow to the sensor to provide an estimate of the pressure within the plenum of the sensor which is itself substantially equal to the pressure outside the sensor; and (g) providing a substantially constant negative pressure to the second tubing which transmits the gas from the pressure sensor thereby to aid the withdrawl of any gas that is introduced into the sensor and reduce the possibility of gas being accidentally injected into the human body if the sensor develops a leak, and to allow the sensor to record negative pressure. - View Dependent Claims (15)
-
Specification