Combination steam and unsaturated chemical vapor sterilizer

• US 4,447,399 A
• Filed: 05/07/1981
• Issued: 05/08/1984
• Est. Priority Date: 05/07/1981
• Status: Expired due to Fees

• Current Assignee: MDT Incorporated
• Original Assignee: MDT Chemical Company
• Inventors: Larkin, Rodney B., Runnells, Robert R., Haak, Peter A., Vandervelden, C. Keith
• Primary Examiner(s): RICHMAN, BARRY
• Application Number:
  US06/261,506
• Time in Patent Office: 1,097 Days
• Field of Search: 422/27, 422/34, 422/33, 422/28, 422/30, 422/62, 422/109, 422/111, 422/113, 422/116, 422/119, 422/295, 422/299, 422/114
• US Class Current: 422/113
• CPC Class Codes: A61L 2/07 Steam
• CPC Class Codes: A61L 2/20 Gaseous substances, e.g. vapours
• CPC Class Codes: A61L 2/24 Apparatus using programmed or automatic operation

Abstract

A combination unsaturated chemical vapor sterilization system and a steam sterilization system utilizing the same sterilizing chamber. It includes a pressure chamber in communication with a source of sterilizing chemicals and water, transport means to selectively deliver sterilizing chemicals or water into the chamber, a heating element to heat the interior of the chamber, and a microprocessor control panel operably associated with the heating element and transport means to control the sterilant composition, the temperature and the pressure within the chamber at any given time in accordance with a preselected setting.

Claims

1. A combination steam and unsaturated chemical vapor sterilizer comprising:

a fixed volume impervious pressure chamber structured to accommodate materials placed therein for sterilizing;

access means associated with the chamber for the insertion into or removal of materials from the chamber;

a source of liquid sterilizing chemicals;

a source of liquid water;

transport means to selectively convey either liquid sterilizing chemicals or liquid water from their respective sources to the interior of the chamber;

a heating element structured uniformly to heat the interior of the chamber, thereby to vaporize said water or sterilizing chemicals within said chamber;

a power source associated with the heating element and transport means to power the heating element and to drive the transport means; and

switching means operably associated with the power source, transport means and heating element to control the chemical or water environment, temperature and pressure within the chamber at a given time in accordance with a preselected setting.

2. A combination steam and unsaturated chemical vapor sterilizer according to claim 1, wherein the source of sterilizing chemicals comprises a solution of approximately 82 percent by weight isopropyl alcohol, methyl alcohol, ethyl alcohol and butanol;

one percent by weight formaldehyde, and 17 percent by weight water, ketone and acetone.

3. A combination steam and unsaturated chemical vapor sterilizer according to claim 1, wherein the source of sterilizing chemicals comprises a solution of approximately 17 to 20 percent by weight formaldehyde, approximately 45 to 50 percent isopropanol, and approximately 30 to 38 percent water.

4. A combination steam and unsaturated chemical vapor sterilizer according to claim 1, including signal means to notify a user that a preselected operating cycle has been completed.

5. A combination steam and unsaturated chemical vapor sterilizer according to claim 1, including warning means to indicate to a user that the sterilizer is malfunctioning.

6. A combination steam and unsaturated chemical vapor sterilizer according to claim 1, including pressure regulating means in communication with the interior of the chamber and operably associated with the switching means to control the pressure within the chamber at any given time in accordance with a preselected setting.

7. A combination steam and unsaturated chemical vapor sterilizer according to claim 1, including recording means in communication with the interior of the chamber to record the temperature, pressure and sterilizing chemical or water composition within the interior of the chamber.

8. A combination steam and unsaturated chemical vapor sterilizer according to claim 1, wherein the switching means comprises:

interface circuitry means operably associated with the transport means and heating element to control in response to a directive signal whether sterilizer chemicals or water are delivered into the chamber by the transport means and the amount of heat emitted by the heating element;

logic means communicably associated with the interface means to generate and transmit directive signals to the interface circuitry means in response to programmed instructions; and

control panel means cooperably associated with the logic means to generate and transmit program instructions to the logic means to determine the sterilizer chemical or water composition, temperature and pressure within the chamber at a given time.

9. A combination steam and unsaturated chemical vapor sterilizer according to claim 8, wherein the interface circuitry means includes means associated with the chamber to generate electronic signals reflecting the temperature, pressure and sterilizer chemical or water composition within the chamber at a given time;

the logic means includes means to translate the electronic signals generated by the interface circuitry means; and

the control panel means includes means to emit audio or visual signals in response to the translated electronic signals generated by the logic means.

10. A combination steam and unsaturated chemical vapor sterilizer according to claim 1, including evacuation means in communication with the interior of the chamber and controlled by the switching means to empty said chamber of air, sterilizing chemicals, or water in accordance with a preselected setting.

11. A combination steam and unsaturated chemical vapor sterilizer according to claim 10, wherein the switching means comprises:

interface circuitry means operably associated with the chamber, transport means, evacuation means and heating element to control in response to a directive signal the evacuation of air from the chamber, whether sterilizer chemicals or water are delivered into the chamber by the transport means, the time the sterilizer chemicals or water remain in the chamber before evacuation, and the amount of heat emitted by the heating element;

logic means communicably associated with the interface means to generate and transmit directive signals to the interface circuitry means in response to programmed instructions; and

a control panel cooperably associated with the logic means to generate and transmit programmed instructions to the logic means to determine the sterilizer chemical or water composition, temperature and pressure within the chamber at a given time.

12. A combination steam and unsaturated chemical vapor sterilizer according to claim 10, wherein the switching means comprises a plurality of manually operated switches, operably associated with the power source, transport means, evacuation means and heating element to enable a user to manually control at any given time whether sterilizer chemicals or water delivered into the chamber, the amount of heat generated by the heating element, and the length of time the sterilizer chemicals or water remain in the chamber.

13. A combination steam and unsaturated chemical vapor sterilizer according to claim 10, including recovery means, and purging means mounted in association with the chamber to remove and store sterilizing chemicals purged from the chamber.

14. A combination steam and unsaturated chemical vapor sterilizer according to claim 13, wherein the recovery means is comprised of a filter made of active alumina impregnated with potassium permanganate.

15. A combination steam and unsaturated chemical vapor sterilizer according to claim 1, including a combination temperature sensor/pressure relief valve having:

temperature sensing means located within the chamber operably associated with the switching means to control the heating element and maintain a preselected temperature within the chamber at a given time; and

a pressure relief valve mounted in association with the temperature sensing means to release partially sterilizing chemicals, vapors, fluids or steam from the interior of the chamber when the pressure inside the chamber exceeds a predetermined level.

16. A combination steam and unsaturated chemical vapor sterilizer according to claim 15, wherein the combination temperature sensor/pressure relief valve comprises:

a hollow, impervious housing having;

an open sensing end, with a cross-sectional diameter less than the cross-sectional diameter of the housing, located within the chamber, and an open exhaust end in communication with the ambient environment exterior to the chamber;

an impervious temperature sensor operably associated with the switching means and slideably mounted within the housing near the sensor end, the cross-sectional diameter of the sensor being less than the diameter of the housing to allow gases, vapors, fluids and steam to pass therebetween, but greater than the diameter of the sensing end, and structured such that a seal is formed when the sensing end contacts the temperature sensor; and

means to urge the temperature sensor against the sensing end until a predetermined pressure is exceeded within the chamber causing the sensor and sensing end to separate partially releasing sterilizing chemicals, fluids, vapors or steam therebetween until the pressure is reduced to or below the predetermined pressure.

17. A combination steam and unsaturated chemical vapor sterilizer according to claim 16, including means to thermally isolate the temperature sensor from the housing.

18. A combination steam and unsaturated chemical vapor sterilizer according to claim 16, wherein the means to urge the temperature sensor against the sensing end comprises a hollow cylindrical compression spring mounted within the housing to urge the sensor against the sensing end.

19. A combination steam and unsaturated chemical vapor sterilizer according to claim 16, wherein the housing is flexible and can be bent to position the sensing end within the chamber at a desired point.