GB2371228A

GB2371228A - Autoclave calibration

Info

Publication number: GB2371228A
Application number: GB0025123A
Authority: GB
Inventors: Richard Paul Harding; Patrick Brian Clayton
Original assignee: DOTTEREL Ltd; Smiths Group PLC; Eschmann Holdings Ltd
Current assignee: DOTTEREL Ltd; Smiths Group PLC; Eschmann Holdings Ltd
Priority date: 2000-10-13
Filing date: 2000-10-13
Publication date: 2002-07-24
Anticipated expiration: 2020-10-13
Also published as: GB0025123D0; GB2371228B

Abstract

An autoclave system comprising an autoclave 1 and calibration apparatus 2. The calibration apparatus includes a computer 20 having an input 21 connected with a temperature sensor 22 and pressure sensor 23. The sensors 22, 23 are located temporarily inside the pressure vessel 11 of the autoclave, such as by extending through sealable passages 24 and 25 in the door 13 of the autoclave. The computer 20 also has an output 26 connected via a cable 27 to a port 28 on the autoclave in communication with the autoclave control unit 17. In operation the sensors 22, 23 are mounted in the pressure vessel 11, and the output 26 connected to port 28. The computer monitors the output of sensors 22, 23 and compares them with the output of the autoclaves built-in sensors 18, 19. If a disparity between the sensors 22, 23 and 18, 19 exists the computer recalibrates the output of the appropriate sensor 18 or 19 via the control unit 17. The system may be run unattended.

Description

AUTOCLAVES This invention relates autoclave systems and methods of calibrating autoclaves.

Autoclaves include a pressure vessel in which are placed articles to be sterilized, such as dental or surgical instruments. The vessel contains a small quantity of water, which is heated to produce steam and to raise the temperature and pressure within the vessel so that sterilization occurs. Autoclaves have various sensors and controls to ensure that the correct pressure and temperature is achieved and maintained for sufficient time to produce effective sterilization. Sensors and controls also ensure that the autoclave operates safely.

In order to ensure correct operation of the autoclave it is necessary periodically to check and recalibrate the various sensors and controls. In some countries, regulations specify that these checks be carried out at specific intervals. The recalibration of an autoclave can be time-consuming and requires a trained technician to carry out. The technician places a temperature and pressure sensor inside the vessel and compares their outputs with the autoclave sensors during a test run. He then calculates the calibration needed and manually adjusts potentiometers appropriately.

It is an object of the present invention to provide an alternative autoclave system and method.

According to one aspect of the present invention there is provided an autoclave system including an autoclave including control means, and calibration apparatus including at least one sensor located to respond to operation of the autoclave, the calibration apparatus having an output connected with the control means and being operable automatically to calibrate the control means in response to the output of said sensor.

According to another aspect of the present invention there is provided calibration apparatus for a system according to the above one aspect of the invention.

According to a further aspect of the present invention there is provided a method of calibrating an autoclave including the steps of locating a sensor to respond to operation of the autoclave, connecting calibration apparatus to an output of the sensor, providing an output from the calibration apparatus to control means in the autoclave to calibrate the autoclave.

An autoclave system and its method of operation, in accordance with the present invention, will now be described, by way of example, with reference to the accompanying drawing which shows the system schematically.

The system comprises an autoclave 1 and calibration apparatus 2 connected with the autoclave.

The autoclave 1 has an outer housing 10 containing a pressure vessel 11 having a rack 12 on which articles to be sterilized are placed. Access to the pressure vessel 11 is via a door 13 at one end provided with a lock 14, which prevents the door being opened unless it is safe to do so. An electrical heating element 15 at the bottom of the vessel 11 heats water 16 within which it is submerged. When the vessel 11 is sealed, operation of the heating element 15 raises the temperature and pressure within the vessel 11. Operation of the heating element 15 is controlled by a control unit 17 in the autoclave, which also receives inputs from various sensors, such as a temperature sensor 18 and a pressure sensor 19. It will be appreciated that a typical autoclave would have various other conventional features, which it is not necessary to describe here in order to understand the present invention.

The calibration apparatus 2 is not connected to the autoclave in normal operation but only when it is necessary to recalibrate the autoclave or check its calibration. The apparatus 2 includes a computer 20 having an input 21 connected with a temperature sensor 22 and a pressure sensor 23. The sensors 22 and 23 are located temporarily inside the pressure vessel 11, such as by extending through salable passages 24 and 25 in the door 13, in a conventional manner. The computer 20 also has an output 26 connected via a cable 27 to a port 28 on the autoclave in communication with the autoclave control unit 17.

In operation, when it is necessary to check or recalibrate the autoclave 1, the sensors 22 and 23 are mounted in the vessel 11 and connected to the input 21 of the computer 20, and the output 26 is connected to port 28. The autoclave 1 is then turned on for a calibration run.

The computer 20 controls the autoclave functions and set-points, which enables the system to run unattended. The computer 20 monitors the outputs of the sensors 22 and 23 to provide initial calibration values or to compare this with information from the control unit 17 representative of the outputs of the autoclave's built-in sensors 18 and 19. If the computer detects a disparity between the outputs from either of the autoclave's sensors 18 or 19 and those 22 or 23 of the calibration apparatus 2 exceeding permitted limits, it provides an output to the control unit 17 to recalibrate the output of the appropriate sensor 18 or 19 to bring it back within the permitted limit. The control unit 17 subsequently responds to the recalibrated outputs of the sensors 18 and 19 so as to ensure correct operation of the autoclave.

It will be appreciated that the invention could be used to recalibrate other functions of the autoclave.

Claims

CLAIMS : 1. An autoclave system including an autoclave including control means, and calibration apparatus including at least one sensor located to respond to operation of the autoclave, calibration apparatus having an output connected with the control means and being operable automatically to calibrate the control means in response to the output of said sensor.
2. A system according to claim 1 wherein the at least one sensor comprises a pressure sensor.
3. A system according to claim 1 or claim 2 wherein the least one sensor comprises a temperature sensor.
4. A system according to any foregoing claim further comprising at least one salable passage in a door of a pressure vessel of the autoclave whereby the at least one sensor can be temporarily located inside the pressure vessel.
5. A system according to any foregoing claim wherein the calibration apparatus comprises a computer adapted to monitor the output of the at least one sensor.
6. A system according to claim 5 wherein the computer is adapted to output at least one initial calibration value of the at least one sensor.
7. A system according to claim 5 or claim 6 wherein the computer is adapted to compare the output of the at least one sensor and to compare the output value with an output of at least one built-in sensor of the autoclave.
8. An apparatus according to claim 7 wherein the computer is adapted to output to the control means to recalibrate the output of the at least one built-in sensor of the autoclave if a disparity between the output of the least one sensor and of the least one built-in sensor exceeds a permitted limit
9. A calibration apparatus for an autoclave system according to any one of claims 1 to 8.
10. A method of calibrating an autoclave including the steps of locating at least one sensor to respond to operation of the autoclave, connecting calibration apparatus to an output of the least one sensor, and providing an output from the calibration apparatus to control means in the autoclave to calibrate the autoclave.
11. A method according to claim 10 wherein the at least one sensor comprises a pressure sensor.
12. A method according to claim 10 or claim 11 wherein the least one sensor comprises a temperature sensor.
13. A method according to any foregoing claim wherein the at least one sensor is temporarily located inside a pressure vessel of the autoclave.
14. A method according to any foregoing claim wherein the calibration apparatus comprises a computer adapted to monitor the output of the at least one sensor.
15. A method according to claim 14 wherein the computer is adapted to output initial calibration values.
16. A method according to claim 14 or claim 15 wherein the computer is adapted to compare the output of the at least one sensor and to compare the output value with an output of at least one built-in sensor of the autoclave.
17. A method according to claim 16 wherein the computer is adapted to output to the control means to recalibrate the output of the at least one built-in sensor of the autoclave if a disparity between the output of the least one sensor and of the least one built-in sensor exceeds a permitted limit.
18. An autoclave system substantially as hereinbefore described with reference to the accompanying drawing.
19. A method of calibrating an autoclave substantially as hereinbefore described with reference to the accompanying drawings.