Kousha Metal Industries co. offers PS-140 series for those instruments which are sensitive to autoclave sterilizer’s temperature and pressure.
This device sterilizes equipment in low temperatures, low temperature means a lower temperature than steam sterilizers that are commonly used in sterilizing since 19th century, steam sterilizers work in temperature higher than 120 degrees, and their process based on this temperatures, but in low temperature sterilization method, the device heats up to lower than 65 degrees which guarantees the equipment functionality after process, and the sterilization process is based on a disinfectant.
Sterilization process can be done by soaking equipment in the disinfectant solution or it can be done by exposing equipment to disinfectant vapor. Because of the equipment limitation of soaking in a solution and to prevent the lack of functionality of the equipment after completing the process, and also to increase the penetration of sterilization, the vapor approach is more reasonable.
There are some methods to sterilize equipment in low temperature. Based on the type of the equipment which is going to be sterilized, and the disinfectant which will be used in the process, the cycle of sterilization is different.
This device uses hydrogen peroxide as a sterilizing agent that is a chemical disinfectant. Hydrogen peroxide is an oxidant, and it can sterilize the equipment which may be temperature-sensitive. It is used for medical sterilization in various concentrations, from 7.5% to higher concentrations up to 90% by weight.Hydrogen peroxide is an oxidizing agent, which means it is a substance that has the ability to oxidize other substances. It is not flammable, but it is an oxidizer, thus it should not be close to flammable materials. This property of hydrogen peroxide is important from two perspectives; first, the material that device is built with, and second is what we should do with the remaining of it on surfaces of equipment that we want to sterile them.
For the first issue, the reasonable approach is that we can use materials that are resistant against corrosion, like stainless steel 316, or anodized aluminum or PTFE, and for second issue we should decide which equipment could be in the sterilization process and which could not, and after the sterilization process, any remaining hydrogen peroxide on the surfaces of equipment should be removed or decomposed. Hydrogen peroxide decomposes spontaneously because it is thermodynamically unstable. And the rate of decomposition increases with rising temperature and also there is a catalysis compound that increases the reaction.
Hydrogen peroxide will also be decomposed if exposed to ultraviolet radiation. This is the fact that plasma sterilizers are based on. They use plasma to energize the molecules in the chamber and it will break the hydrogen peroxide molecules into radicals, which they recombine again and make water and oxygen.
Then there is this way to decompose any residues of hydrogen peroxide that did not be drawn out of the chamber
Sterile Cycle Overview
The Sterile cycle is designed in a way which is very user friendly and also without any error. We considered two types of cycles according to the items that have to be processed. For the surfaces of the equipment and the items that have not difficult spaces to penetrate, the standard (short cycle) cycle is appropriate. For the lumens or the items that have more difficult areas to penetrate the lumen cycle (Long cycle) is defined. The steps in both cycles is the same but the purification time is different.
The steps of our sterile cycle is explained bellow
After the device is turned on, the main controller checks the chamber’s walls temperature, if it was not warmed up, the heater process will be start, otherwise the operator can proceed the cycle. We designed a cycle starting wizard program in order to ease the starting process. The wizard have these 4 steps:
1- Loading: In order to load the items inside the chamber
2- Cycle choosing: In order to choose the cycle, considering the items which loaded in loading step.
3- Loading Hydrogen Peroxide cartridge: In order to load the disinfectant.
4- Starting the cycle: In order to start the cycle.
Before the cycle starts, and after the device is turned on, the air compressor would be turned on and provide the air pressure during the cycle. Also the warming up procedure checks the temperature of the chamber walls all the time.
When the operator start a cycle these processes will be taken place:
1- The door will be closed and if it’s closed it would be checked again.
2- The delivery nozzle inserted in to the cartridge.
3- The vacuum pump will be turned on.
4- After about 20 seconds, the vacuum valve will be opened and the hydrogen peroxide will be measured and will be transferred to the vaporizer.
5- Inside the vaporizer by controlling pressure and the temperature the water of the solution will be drawn out and more concentrated hydrogen peroxide will be remain inside the vaporizer.
6- In the injection stage the concentrated hydrogen peroxide inside the vaporizer will be heated up and in the low pressure it would be evaporated.
7- After evaporation of hydrogen peroxide and injecting it into the chamber the diffusion stage would be started. In this stage the items would be in contact with hydrogen peroxide.
8- All the stages before will be repeated in order to make us assure about the cycle.
9- In the vacuum stage all the hydrogen peroxide will be drawn out from the chamber and after a high vacuum a plasma would be applied inside the chamber to decompose the remaining hydrogen peroxide on the items.
10- The filtered air will enter into the chamber and the cycle will be ended.