Title:
Pressure sensor-timer alarm for pressure sensitive devices
United States Patent 3906934


Abstract:
A pressure sensor-timer alarm for pressure sensitive devices, e.g., mechanical breathing devices, having a pressure sensor, e.g., diaphragm which is sensitive to pressure changes in the pressure sensor device, e.g., pressure changes in the inspiration and expiration phases of a breathing cycle. In combination with the pressure sensor is a plunger having a magnetically mounted switch actuator which actuates a switch in response to pressure changes from the diaphragm. A failure to actuate the switch in either phase of the pressure sensitive cycle, e.g., breathing cycle, within a preset time interval causes the actuation of an alarm signal. The switch actuator is slidably adaptable to compensate for any change in the base pressure level of a pressure sensitive device, e.g., breathing device, and still maintain the preset time monitoring sequence.



Inventors:
HAVERLAND WILLIAM H
Application Number:
05/495301
Publication Date:
09/23/1975
Filing Date:
08/07/1974
Assignee:
HAVERLAND; WILLIAM H.
Primary Class:
Other Classes:
335/205, 340/573.1, 340/626
International Classes:
A61B5/113; A61M16/00; (IPC1-7): A61B5/00; A62B7/00
Field of Search:
128/2R,2
View Patent Images:
US Patent References:
3588864N/A1971-06-28Gaulke
3566387N/A1971-02-23Schoener et al.
3333584Pressure breathing monitor1967-08-01Andreasen et al.
3120843Monitor for mechanical respirator1964-02-11Hyman
2834953Pressure indicating system1958-05-13Bechberger et al.
2473922N/A1949-06-21Tobias



Primary Examiner:
Howell, Kyle L.
Parent Case Data:


This application is a continuation-in-part of application, Ser. No. 362,276, filed May 21, 1973, now abandoned which application is a continuation-in-part of Ser. No. 152,385, filed June 11, 1971, now abandoned.
Claims:
What is claimed is

1. A pressure sensor-timer alarm for use in mechanical breathing devices which comprise in combination, a diaphragm chamber mounted on a support and communicatively connected to a mechanical breathing device, a diaphragm mounted in the chamber, a ferro-magnetic metallic plunger mounted on the diaphragm and reciprocally mounted on the support, a permanent magnet magnetically and slidably mounted on the plunger, a pluality of stop means on the support restricting the reciprocal movement of the magnet, a switch means and a plurality of stationary contact means mounted on the support, the switch means in engagement with the magnet and movable between the contact means, a plurality of timers communicatively connected to the switch means and the contact means and an alarm communicatively connected to the timers.

2. A pressure sensor-timer alarm for use in pressure sensitive devices which comprise in combination, a pressure sensor chamber mounted on a support and communicatively connected to a pressure sensitive device, a pressure sensor mounted in the chamber, a ferro-magnetic metallic plunger mounted on the pressure sensor and reciprocally mounted on the support, a permanent magnet magnetically and slidably mounted on the plunger, a plurality of stop means on the support restricting the reciprocal movement of the magnet, a switch means and a plurality of stationary contact means mounted on the support, the switch means in engagement with the magnet and movable between the contact means, a plurality of timers communicatively connected to the switch means and the contact means and an alarm communicatively connected to the timers.

3. The pressure sensor-timer alarm of claim 2 wherein the pressure sensor is a diaphragm.

Description:
This invention relates to alarm systems. More specifically, it relates to a pressure sensor-timer alarm system for pressure sensitive devices.

In bio-medical engineering devices, such as cardiac assist devices, e.g., artificial heart, the artificial lung and the artificial kidney, it is vitally important that the blood pressure be monitored during the time that a patient is using such devices, to detect an unwanted rise or fall in blood pressure.

It is also vitally important when patients are using mechanical breathing devices, e.g., Intermittent Positive Pressure Breathing, Continuous Positive Pressure Breathing or Positive and Expiratory Pressure devices, that the inspiration or expiration phase of the breathing cycle be monitored for possible failure of the device. It is also equally important that any disconnect of the patient from the device be monitored.

In chemical processes requiring pressure conditions, e.g., above or below atmospheric pressure, it is important that the pressure vessels be monitored and the reactions maintained within acceptable pressure limits.

It is, therefore, an object of this invention to provide a pressure sensor-alarm system for pressure sensitive devices.

It is also an object of this invention to provide a pressure sensor-alarm system for mechanical breathing devices which will detect patient disconnect or failure or the breathing device in either the inspiration or expiration phase of the breathing cycle and signal an alarm.

It is a further object of this invention to provide a pressure sensor-alarm for mechanical breathing devices which will compensate for any change in the base level of a breathing device and still maintain a preset time monitoring sequence for a breathing cycle.

These and other objects of this invention will become apparent from the following detailed description and drawings wherein:

FIG. 1 is a partial cross sectional view of a pressure sensor-timer alarm of this invention.

FIG. 2 is a top view in partial cross section of the pressure sensor-timer alarm of FIG. 1.

Broadly, this invention provides a pressure sensor-timer alarm for pressure sensitive devices. The alarm has a pressure sensor, which is sensitive to pressure changes in the monitored device. In combination with the pressure sensor is a plunger having a magnetically mounted switch actuator which actuates a switch in response to the transmission pressure changes from the pressure sensor. A failure to actuate the switch within preselected limits of the pressure sensitive cycle, within a preset time interval causes the actuation of an alarm signal. The switch actuator is slidably adaptable to compensate for any change in the base pressure level of a pressure sensitive device, and still maintain the preset time monitoring sequence.

While the pressure sensor-time alarm of this invention is applicable to pressure sensitive devices such as biomedical engineering devices such as artificial heart, artificial lung, artificial kidney, and the like, mechanical breathing devices, pressure sensitive chemical reaction vessels and devices, the invention will be best understood from a detailed description of the apparatus of this invention and its use in mechanical breathing devices.

Referring now to FIG. 1, there is depicted a pressure sensor-timer alarm 10 of this invention. A pressure sensor, e.g., diaphragm 11 is mounted in a pressure sensor chamber, e.g., diaphragm chamber 12 and is actuated by changes in pressure during the inspiration and expiration phases of the breathing cycle. These pressure changes are communicated to the pressure sensor chamber 12 and hence to the diaphragm 11 from a breathing device (shown generally at 15) via a connecting air tube 13. Mounted on the diaphragm 11 is a ferro-magnetic metal plunger 14, having a spring 16 affixed at the base 17 of the plunger 14. A permanent magnet 18 is magnetically attached to the plunger 14. Although the magnet 18 is shown attached to the underside of the plunger 14, it is not a limitation of this invention, as it will be appreciated that the magnet 18 may be attached on top of the plunger 14 or on side of it. The plunger 14 in its reciprocal motion in relation to changes in position of the diaphragm 11, is guided in its movement by guides 19. The diaphragm chamber and the guides are affixed to a support 21. The permanent magnet 18 is restricted in its reciprocal motion in relation to the plunger 14, by stops 22 and 23. Stops 22 and 23 are on the support 21. A contact switch 24, e.g., a snap action switch engages magnet 18, and is maintained in engagement with the magnet 18 by a spring 25. The reciprocal motion of the magnet 18 causes the contact switch 24 to alternatively engage stationary contacts 26 and 27 (while alternatively compressing and expanding the spring 25). The contacts 26 and 27 are each connected to a timer system. Power for the timer (and alarm) system is supplied via plug 28, one side of which is connected to contact 24 via wire 29. and the other side is connected to the timer system, e.g., timers 31 and 32 via wires 33, 33a, and 33b. Both timers 31 and 32 are connected to contacts 26 and 27 to complete the circuit via wires 35 and 36. Both timers 31 and 32 are also connected to an alarm 34 via wires 37, 37a, and 37b.

In operation as the diaphragm 11 responds to changes in pressure from the breathing device 15, the plunger 14 maintains a reciprocal motion withing the guides 19. The spring 16 aids in returning the plunger 14 and the diaphragm 11 to the lowest pressure position of the breathing cycle. At either end of the breathing cycle (inspiration or expiration), the contact switch 24 which as moved in response to the movement of the magnet 18, actuates the stationary contacts 26 or 27 respectively. For example, assume the initial pressure variation during the inspiration and expiration phases of the breathing cycle was from 0 to 12cm of H2 O. As the pressure in the housing 12 rises from 0cm of H2 O to 12cm of H2 O, the diaphragm 11 and the plunger 14 will move carrying magnetically attached magnet 18 from stop 22 to stop 23, thereby causing the contact switch 24 to move from contact 26 to contact 27. As the pressure falls in the opposite half of the cycle and drops from 12cm of H2 O to 0cm of H2 O the action will be reversed and the magnet 18 will return to its initial state at stop 22 and the contact switch 24 will move from contact 27 to contact 26. The timers 31 or 32 sense a signal from the closed circuit between contact switch 24 and contact 26 or 27 according to a preset time interval. For example, on inspiration when the pressure rises to 12cm of H2 O for a time exceeding 8 to 10 seconds, the timer 32 will actuate the alarm 34. Conversely, upon expiration when the pressure drops to 0cm of H2 O for a time exceeding 12 to 14 seconds, the timer 31 will also actuate the alarm 34. The alarm 34 may be a noise device, e.g., bell, or a light device, e.g., flashing red light.

The device of this invention adds a flexibility to an alarm system in that it allows the pressure sensor-timer to compensate immediately for changes in the base pressure of the breathing device. For example, if it is desired to raise the base pressure from 0cm of H2 O to 7cm of H2 O (for the purpose of applying Continuous Positive Pressure Breathing), the pressure will now vary between 7cm of H2 O and 19cm of H2 O. This new base pressure of 7cm of H2 O will not allow the diaphragm 11 and the plunger 14 to return to the original 0cm of H2 O position, and the magnet 18 will not properly activate the contact switch 24 without being repositioned. Therefore, to compensate for the new pressure range, the position of the magnet 18 is automatically readjusted on the plunger 14. As the pressure in chamber 12 rises to 19cm of H2 O, the diaphragm 11 and the plunger 14 will move further (than they did at 12cc of H2 O); but since the magnet 18 is against the stop 23 it cannot move, and therefore, the plunger 14 will slide over the magnet 18 to reposition the magnet on the plunger. As the pressure in the chamber 12 begins to fall from 19cm of H2 O, the diaphragm 11 and the plunger 14 will begin to return with magnet 18. As the pressure in the chamber 12 falls to 7cm of H2 O, the diaphragm 11, the plunger 14 and the magnet 18 will have moved to a position where magnet 18 has returned to stop 22.

Since the pressure in the system will now vary between 7cm and 19cm of H2 O, the magnet 18 will continue to move the contact switch 24 between contacts 26 and 27 due to the fact that the magnet 18 has taken a new position on plunger 14.

This ability to monitor immediately changes in base pressure is accomplished by the fact that magnet 18 is restricted by stops 22 and 23 in its movement in relation to plunger 14. When magnet 18 is held at stop 23, the plunger 14 is still free to move in response to a pressure increase in the diaphragm 11. When the new base pressure range is reached, and the plunger 14 starts its return in response to the decrease in pressure in the diaphragm chamber 12, the magnet 18 then moves with the plunger 14, towards stop 22. The distance that magnet 18 travels between stop 22 and 23 will correspond in the above example to a pressure difference of 1cm to 12cm of H2 O.