Anesthetic gas control apparatus

• US 4,345,612 A
• Filed: 06/09/1980
• Issued: 08/24/1982
• Est. Priority Date: 06/13/1979
• Status: Expired due to Term

• Current Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Tsuzuki, Akira, Urushida, Yoshihisa, Koni, Tuyoshi
• Primary Examiner(s): Spiegel, H. Jay
• Application Number:
  US06/157,581
• Time in Patent Office: 806 Days
• Field of Search: 137/101.19, 137/101.21, 137/DIG.1, 137/554, 137/599, 73/718, 73/861.52, 128/203.12, 128/200.19, 128/204.21, 128/203.14, 128/203.25, 340/711, 340/712, 340/627, 340/629, 340/636, 340/663, 340/522
• US Class Current: 137/101.19
• CPC Class Codes: A61M 16/00 Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes stimulating the respiratory movement by mechanical, pneumatic or electrical means, iron lungs combined with gas breathing means A61H31/00
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/1015 using a gas flush valve, e.g. oxygen flush valve
• CPC Class Codes: A61M 16/104 specially adapted for anaesthetics A61M16/18 takes precedence
• CPC Class Codes: A61M 16/203 Proportional
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: B01F 23/19 Mixing systems, i.e. flow charts or diagrams; Arrangements, e.g. comprising controlling means
• CPC Class Codes: B01F 35/2111 Flow rate
• CPC Class Codes: B01F 35/2206 Use of stored recipes for controlling the computer programs, e.g. for manipulation, handling, production or composition in mixing plants B01F33/846 takes precedence
• CPC Class Codes: B01F 35/2211 Amount of delivered fluid during a period
• CPC Class Codes: B01F 35/833 Flow control by valves, e.g. opening intermittently
• CPC Class Codes: G05D 11/132 by controlling the flow of the individual components G05D11/133 takes precedence
• CPC Class Codes: Y10T 137/2529 With electrical controller
• CPC Class Codes: Y10T 137/8242 Electrical

Abstract

An apparatus for supplying a mixture of oxygen and an anesthetic gas at a predetermined flow rate and mixture ratio. The flow rate and mixture ratio are controlled by means of electrically operated throttle valves, responsive to output signals from an electronic control system, generated in accordance with data stored in the control system and with input signals applied to the computer from means for sensing the flow rates of the oxygen and anesthetic gas. Desired flow rate and mixture ratio data may be input by using a numeric keyboard, and are digitally displayed.

Claims

1. An apparatus for supplying a predetermined rate of flow of an anasthetic gas comprising a mixture of a first gas and a second gas, said first and second gases being provided from a first gas source and a second gas source, said apparatus comprising:

a first electrically controlled throttle valve coupled to receive said first gas from said first gas source, for producing a controlled flow thereof;

a second electrically controlled throttle valve coupled to receive said second gas from said second gas source, for producing a controlled flow thereof;

first flowrate sensing means for measuring the rate of flow of said first gas when output from said first electrically controlled throttle valve and for producing electrical signals of digital form indicative of the magnitude of said rate of flow;

second flowrate sensing means for measuring the rate of flow of said second gas when output from said second electrically controlled throttle valve and for producing electrical signals of digital form indicative of the magnitude of said rate of flow of the second gas;

data input means for generation of digital data to specify a predetermined total rate of flow of said anasthetic gas and to specify a predetermined mixture ratio of said first and second gases;

an electronic control system coupled to receive said digital electrical signals from said first flowrate sensing means and from said second flowrate sensing means and to receive said digital data from said data input means, and comprising memory circuit means for storing said digital data from said data input means and digital data processing circuit means for comparing said predetermined total rate of flow of said anasthetic gas and said predetermined mixture ratio of said first and second gases as represented by said stored digital data with an actual total rate of flow of said anasthetic gas and an actual mixture ratio of said first and second gases as represented by said digital electrical signals from said first and second flowrate sensing means and for producing control signals on the basis of said comparison, said control signals being applied to said first and second electrically controlled throttle valves for thereby bringing said actual total rate of flow of anasthetic gas and actual mixture ratio of said first and second gases into coincidence with said predetermined total rate of flow of said anasthetic gas and said predetermined mixture ratio of said first and second gases respectively;

electro-optical display means for displaying said predetermined total rate of flow of said anasthetic gas and said predetermined mixture ratio of said first and second gases stored in said memory circuit means; and

means for mixing said first and second gases after measurement of the rates of flow thereof by said first and second flowrate sensing means, for thereby providing said anasthetic gas further comprising first and second fixed throttle valves having the outputs thereof coupled to said means for combining the first and second gases; and

manually a actuated gas switching means for selectively supplying either (1) said first gas from said first gas source to said first electrically controlled throttle valve and said second gas from said second gas source to said second electrically controlled throttle valve, or (2) said first gas from said first gas source to said first fixed throttle valve and said second gas from said second gas source to said second fixed throttle valve, and further comprising pressure controlled gas switch means located downstream of said second fixed throttle valve and responsive to pressure from said first gas source to allow flow of said second gas past said gas switch means only when the pressure of said first gas source is above a predetermined minimum pressure.

2. An apparatus for supplying an anasthetic gas according to claim 1, in which each of said first and second flowrate sensing means comprises a flowrate sensor responsive to a gas flow for producing electrical signals to indicate the magnitude thereof and an analog-to-digital converter circuit for converting said electrical signals into digital electrical signals.

3. An apparatus for supplying an anasthetic gas according to claim 1, wherein said memory circuit means includes non-volatile memory circuit means for storage of said input data, whereby said data is retained in storage in said non-volatile memory circuit means in the event of a cessation of electrical power supply to operate said apparatus.

4. An apparatus for supplying an anasthetic gas according to claim 1, in which said data input means comprises a keyboard including a plurality of keys and a plurality of switches actuated thereby.

5. An apparatus for supplying an anasthetic gas according to claim 1, and further comprising a source of a standard frequency timebase signal, and in which said electronic control system is further operative to compute a volume of each of said first and second gases consumed by said apparatus from said first and second gas sources during each of successive time intervals defined by sad timebase signal and to cumulatively add said computed volumes for thereby computing cumulative consumptions of said first and second gases by said apparatus.

6. An apparatus for supplying an anasthetic gas according to claim 1, and further comprising battery-operated means coupled to said apparatus for detecting failure of electrical power supplied to said apparatus and for generating an audible alarm signal in response to such detection.

7. An apparatus for supplying an anasthetic gas according to claim 1, and further comprising a first solenoid valve coupled to receive said first gas from said first gas source and a second solenoid valve coupled to receive said second gas from said second gas source, each of said first and second solenoid valves being responsive to control signals produced by said electronic control system for selectively establishing an open state in which a supply of gas is enabled or a closed state in which a supply of gas is cut off.

8. An apparatus for supplying an anasthetic gas according to claim 1, in which said display means further comprises warning indication means, and in which gas data representing a difference between said predetermined total rate of flow of said anasthetic gas and said actual total rate of flow of said anasthetic gas and representing a difference between said predetermined mixture ratio of said first and second gases and said actual mixture ratio of said first and second gases is generated by said electronic control system, and further wherein said electronic control system acts to detect when the magnitude of each of said differences exceeds a predetermined limit value and activates said warning indication means to produce a perceptible warning signal when said limit value is exceeded.