DE1492500A1 - Method and device for sterilizing materials - Google Patents

Description

Procedure and performing sun sterilizing materials.

The invention relates to a method and a device for sterilizing of materials by treatment with a gaseous chemical sterilizer and is particularly suitable for di. Use of the gaseous mixture of ethyl methyne as sterilization @ medium.

For many years, steam @ terili @ ization has been used at high tomperatures the usual sterilization treatment. Because of the use of steam sterilization on many materials, such as s.B. Plastic, adhesives, etc., problems that arise and because of the resulting oxidation clay surgical instruments and others Metal objects has the use toa chemical gases as sterilizing agents found w @@@@ daily economic success.

E @ was found that # Äthylenexyd as a result of @@ iner chemical big sheep @@ n ice is the beston suitable sterilization means, because ej at low @@ mperaturen all Fermen v.i organisms available- @ i @ mä # ig quickly merstört @ hn @ korrediarende Effect on di. materials to be sterilized.

In the practical use of ethylene oxide as a sterilizing agent However, a number of problems have arisen. It is very flammable and When mixed with air, it is explosive in certain proportions. It's for man toxic and causes blisters on human skin if left on the same remain on objects that come into contact with the human body.

Various solutions to the problem @ of the advantages and Post-treatment of the items or the area suggested before and after chemical sterilization with ethylene oxide or with non-explosive gaseous Mixtures containing ethylene oxide.

A verb @@@@ rten method for sterilization with Äthylenexyd is described in American patent specification 3,068,061 / 2. An economical The feasible method for sterilization with ethylene oxide comprises the following steps or minor changes to the same: 1. The evacuation of a sterilization container to remove the air.

2. The moistening of the container and the goods to create a Environment with corresponding amounts of moisture, because this is known to be an important one This is a prerequisite for effective sterilization.

3. Din ethylene oxide containing gas mixture is in the chamber one let us generate a certain increased pressure.

The chamber is set to elevated temperatures in the range of 38 - 55 ° C heated. The pressure chosen is generally of the concentration desired of the Ethylenexyde dependent. Most of the G @@ mixtures used in practice, which are in safe, non-flammable areas are 10 wt.% ethylene oxide in Carbon dioxide, 12% by weight of ethylene oxide or 27.3% by volume in dichloro -tluoromethane (the commercially available under the trademark Preon-12) and 11-12% by weight of ethylene oxide in a mix of @@@ on-11 and Freen-12.

4. The gas pressure increases for a predetermined period of time get right.

5. The chamber is vented and / or evacuated and the gas is removed from the Remove chamber.

6. Sterile (filtered) air is admitted into the chamber.

Liner of the disadvantages of such a system is that by the evacuation does not remove all of the remaining air.

The amount of air left in the sterilization container is critical at low operating pressures. In these circumstances the stratification can occur seriously impede the sterilization process.

Another disadvantage is that some species can use high vacuum seriously damaged by materials. When the chamber is evacuated, it will be frequent Packs deformed or burst due to internal pressure. In some cases The damage can be caused by slowing down the rate of evacuation minimized or avoided, but this is very time consuming.

The use of the fireproof kitchen oxide mixtures requires usually high pressure to provide sufficient gas concentration for safe sterilization to achieve. The rapid action of external pressures on the packs through introduction of the sterilizing gas after evacuation often causes the deformation and the collapse of the packs. If a lower one to avoid damage than the sufficient vacuum generated and a lower than the sufficient pressure a compromise of the best sterilization conditions is achieved, by leaving the greater part of the air left behind and inadequate Ethylene oxide concentrates are used.

A less satisfactory process that is used economically includes the use of 100% ethylene oxide, which is very much when mixed with air is explosive. This procedure requires hence the evacuation of the Sterilization chamber with a very high vacuum to make the formation more explosive Avoid mixing the ethylene oxide with the remaining air.

The disadvantages described above with regard to the vacuum apply for di @@@@ less satisfactory procedures to a greater extent. The procedure is extremely dangerous. It requires trained and experienced. Staff and one explosion @@ icher @ plant. E @ is common, except for 660 mm of mercury @ column to evacuate and introduce 100% ethylene oxide until it is during sterilization a negative operating pressure of 381 @@ mercury column, which is still leaves about 22 ß of residual air in the chamber. After completion of the sterilization process @ special rinsing processes must be carried out, which consume considerable material Subject to pressure changes from a very low sub-atmospheric Pressures can range up to very high pressures. There is also a final Flushing the remaining ethylene oxide is time-consuming.

According to the invention, the displacement is within the chamber or the air in the container is provided by the chemical sterilization @ gas itself, such as B a non-explosive ethylene oxide mixture. Since the density of ethylene oxide or the threat of explosive mixtures of ethylene oxide much higher and bigger than air, the same will change when it is introduced into the chamber layers. Preferably there is an outlet opening at the upper end of the sterilization container provided so that the denser sterilizing gas moves the stratified air upward repressed. Iniolge the greater vapor density of the gas can reduce the displacement in less also effectively by introducing the gas at the top or at any selected body of the chamber. The barring is therefore also present Sterilizers applicable.

E @ has also been found to be extremely desirable to have humidification make after the air through the sterilizing gas Completely has been displaced, and in the sterilization chamber during sterilization to receive a selected state of the art.

The invention relates to an improved method and a Device for sterilization with a chemical gas.

Another object of the invention is a simplified method and a device for sterilizing with a chemical sterilizing agent.

An important feature of the invention is that it is a koatspielige Evacuation device for a satisfactory sterilization with a shemischen Sterilisierungsges is dispensable.

Another important object of the invention is a sterilization method, the process known from deF is competitive and otherwise economically suitable is, and the less flammable and less exclusive mixtures of ethylene oxide gas can use.

A method is also an important subject of the invention to displace the air inside the sterilization container by the chemical Sterilization gas itself.

Another important object of the invention is a verb Process, since the humidification of the chamber and the goods after the displacement of the Air is included by the sterilizing gas.

Another aspect of the invention is a sterilization device 1 in which the air is displaced by a chemical sterilizing agent which is inserted at the lower end of the device.

Yet another object of the invention is a method of sterilization of the type described above, which the goods before the introduction of the sterilizing gas brings into the chamber in the desired state.

Further features and distributions of the invention result from the following Description.

The drawing shows: FIG. 1 a schematic representation of a Embodiment of the invention.

Figures 2-5 schematically illustrate air molecules in one Sterilization chamber under the conditions described below.

According to the invention, the greater vapor density of ethylene oxide or non-flammable mixtures of the same in relation to air to displace the same exploited. The air in a sterilization chamber 10 is through the Introduction of the denser ethylene oxide that of the non-flammable mixture of the same displaced upwards, which is easily stratified and not distributed in the air. However, it is preferably introduced through a lower inlet 16 into the Sterilization container and the air is through an upper outlet opening 12 in the Near the top of the sterilization container. repressed. The essential The stages of the new procedure are as follows: t. The air in the chamber gets through displaced a sufficient volume of a chemical sterilizing gas, In the to immerse the object to be sterilized in the gas.

9. The sterilizing gas is used during a period of time kept in the chamber, u @ cause the sterilization of the object z.

The displacement of the air is preferably preceded by an evacuation.

As stated above, however, this is necessary for the execution of the Invention not essential. Evacuation is therefore desirable in order to avoid the Luftueleküle in the goods to be sterilized to a minimum, thereby reducing penetration of moisture and the sterilization gas in the goods is much easier will.

The displacement of the air by the sterilizing gas can result in a humidification process precede at which moisture in the form of steam at 18 is introduced into the chamber and is maintained there for a preselected period of time establish previously determined relative humidity @ nivean. Such humidification is particularly desirable if the previous evacuation is to be pterilized Tries to dry out the object.

But even if there is no evacuation, humidification is desirable Prerequisite for the process to be a previously selected in the goods to be sterilized Establish humidity @ level.

During the air displacement process of the process @, a will not be detonable ethylene oxide G @@ gemi @ ch pulsing or continuously into the stabilization chamber introduced and brought to a slight overpressure at 32 by heating.

Here, the air outlet port 12 is opened, while this is not flammable, heated ethylene oxide gas mixture is further introduced into the chamber, preferably at 16 at the bottom of the same until all of the air is displaced and the chamber is completely filled with the sterilization gas. The amount of gas which the sterilization chamber drops at the desired pressure setting calculated in advance on a weight basis. A display device can indicate the filling point monitor and lock the outlet opening. but can also be used for the desired The time required for filling with a certain flow rate is determined and adjusted.

The gas is held in the chamber for a period of time begins after the air is completely displaced and the chamber with the sterilizing gas is filled. The period begins at a predetermined pressure, preferably at a slight overpressure, which for the purposes of the invention is considered to be "essentially atmospheric pressure "by adding additional gas when the pressure concentration of the gas due to absorption or leakage below a selected one Level sinks.

Simultaneously with or after the air is expelled from the chamber and during the entire sterilization @ the moisture continues in introduced the chamber in order to moisten the chamber and the goods or to close them again moisturize. In this way, a selected moisture level is created in the goods and maintained in the surrounding area of the chamber. This humidification eder Re-humidification is extremely desirable because the greater toil of the moisture n with the air displaced by the sterilization tag @@ will be discharged. En takes place an escape of moisture from the goods, because they then have a higher moisture concentration than the surrounding gas atmosphere. The humidification or re-humidification should ensure the dynamic moisture flow into the goods to be sterilized. It is therefore necessary to ensure a continuous moisture @ gradient, to preserve the dynamics of diffusion. The humidification or re-humidification keeps the moisture in the goods and also serves as a carrier that strengthens the sterilization gas drives into the goods.

After completion of the sterilization process, the chamber is up to sucked off atmospheric pressure. Although not strictly necessary, it can The sterilization process is followed by a rinsing process in order to remove any remaining gases remove. Preferably air is introduced at the top and gas at the bottom sucked off.

The preparation, the working method and the follow-up treatment, as well the temperatures, pressures and humidity conditions can be consistent with American patent specification 3,068,064 or with other satisfactory ones Be conditions that are not the subject of the @@@@ dung hilden.

The new process, described in an understandable way, excludes all air the sterilizer during the sterilization period, excluding the air, which is enclosed within the goods themselves or which is recorded and which too passed by the following evacuation @ not removed in a satisfactory manner can be.

A sterilization chamber 10 is shown schematically in FIGS. 2, in which two packages of goods 11 and 13 are to be sterilized. The points 15 are air molecules. Fig. 2 illustrates the state of air molecules after the goods have been driven into the chamber. Fig. 3 illustrates the state after Evacuation and shows that there is air left in the chamber.

Fit. illustrates the stratification of air molecules after introduction a chemical sterilizing gas 17 into the chamber according to the derseit known sterilization processes. The arrows 21 illustrate the very slow one Diffusion of stratified air into gas 17. Diffusion of air and gas dilutes the gas and it is therefore essential that the sterilization be carried out with safe Gas mixing takes place under increased pressures, and is necessary for the execution of the sterilization to obtain the necessary gas concentration.

Fig. 3 schematically illustrates the effectiveness of the new method, Preferably, after evacuation of the air to the state shown in Fig. 3 (um reduce the air molecules in the goods u) the gas 17 is introduced into the chamber 10 and the remaining air is completely displaced. The table below illustrates the under the specified gearbox pressures according to in Fig. 1/2 given known method, air remaining in the chamber in% by volume.

Operating pressure remaining air in volume% at kg / cm2 1/2 23> 0 % 1 0.0 13.3% 1.5 0.5 8.9% 2.0 1.0 6.7 r 2.5 1.5 5.3% 3.0 2.0 4.5% at the new one Process, there is no remaining air due to the displacement process, with the exception of the air contained in the goods or cards.

The new process has the distinct advantage that the otherwise required sudden pressure change is avoided, which results from the evacuation and the increased pressures and which the packs to be silisboiled by bursting or deformed to @@@@ fall.

As has also already been stated, it is an expensive high-vacuum system dispensable. The diffusion of ethylene oxide enables easy penetration into the object to be sterilized without the need for vacuum or pressure, ind makes the same particularly suitable for use in the present method.

The invention has the further Yortetl sui that no high pressure container required one. The sinking of the extremely desirable Äthylenexyd-Fr @@ n-mixtures as a sterilizing gas results in an economical process while it used to be from an economic point of view, such mixtures in competition were not practical to be used with the ethylene-oxide-carbon dioxide mixtures.

D @ chlorodifluoromethane available under the trademark Freon had the advantage in mixtures with ethylene oxide that there were high concentrations of ethylene oxide under essentially @ atmospheric pressure (a very small Overpressure). A freon-ethylene oxide mixture with an ethylene oxide concentration of 12 Ges.-4 and 27.3 volume% at essentially monopherical pressure is both safe as well as satisfactory for sterilization. In the wementlichen atmospheric Pressure or a slight overpressure can be due to the vapor density of the Freen-Mi @ chungen maintaining a desirable concentration of 450 mg ethylene oxide can be guaranteed per cubic liter. The vapor density of the Freon mixtures is about four times the density of the air, during carbon dioxide-ethylene oxide mixtures only have about twice the air density.

In this way, non-flammable Fluer-Kchlensteff mixtures, such as ethylene oxide freon sterilization gas mixtures as economical as carbon dioxide mixtures for the currently known processes in which the sterilizing gas is below essential elevated pressures is maintained. According to the new process, it is therefore economical to to use a safer gas mixture. To be appropriate with carbon dioxide mixtures Concentrations of ethylene oryd with almost 450 mg per liter or 12% by weight of ethylene oxide or 27.3% velur at essentially atmospheric pressure would have to be obtained Flammable mixtures with a weight or volume ratio of 30% ethylene oxide Carbon dioxide can be used. However, carbon dioxide mixtures are only @ 0 in weight and volume ratio of 10% Ethylemexyd safe. Therefore, if carbon dioxide mixtures it is desirable that they be used under known elevated pressures stand. Since both propylene oxide and methyl chloride are denser than air, they are tough they would be useful as a satisfactory sterilizing gas for the new process.

The greatest damage that occurs when using the well-known Sterili @@ - gates can be observed, results from the release of pressure after the end of the sterilization process. Because the internal pressure of the packs has had an opportunity to change during the sterilization with the external pressures. results in a sudden release of pressure a forced expansion and a burst, in particular if still a subsequent evacuation eriolgt. This danger is through the new barring eliminated.

For the first time, a method is obtained in which the vacuum and Pressure limits for pretreatment and operation can be changed to any Risk of bursting or collapsing of the packs to be sterilized with the To dispose of the goods contained therein without creating ideal sterilization conditions to renounce.

Now the device for Ausf; their use of the procedure will. The device consists of a double-walled heated container 9, which delimits a sterilization chamber 10 with an outlet opening 12 at the top End and a finla # opening 16 at the lower end. As can be seen from the description of the procedure this construction enables that which enters chamber 10 at 16 denser sterilizing gas nqch the air up and through the outlet port 12 outside when it is open.

The relative humidity in the chamber is determined according to the procedure Dampi regulated, which is fed to the sterilization chamber through line 18 which includes a solenoid valve 19. The valve 19 is by a (not shown) GeFegelt measuring device, which responds to the relative humidity in the chamber, to introduce steam into the chamber through line 18 and thereby accordingly the method described above in the same has a selected relative humidity to maintain.

By using an infrared gas analyzer (not shown) or some other known device which determines whether the air is completely is displaced, the period of time can be determined, which is below the according to the procedure selected conditions for complete displacement of the air is necessary to thereby to obtain a laterally limited displacement period. A solenoid valve 20 operated by a switch (not shown) closes at the end of this displacement period. If buttocks that prominent described If an evacuation is carried out beforehand, there is a between the sterilization chamber and a vacuum pump arranged valve 22 is opened during the duration of the evacuation.

The sterilizing gas supplied to the inlet port 16, which is in liquid Form contained in a treachery container 21/2 goes through a solenoid valve 26, which is controlled by a pressure switch (not shown), which is arranged in the device and is responsive to the pressure in the chamber. The valve 26 remains open when the pressure in the sterilization chamber falls below a previously selected height.

A heating device or a heat exchanger is located in the gas supply line 28 arranged, which heats the gas to a pre-selected temperature of 65 - 82 ° C. The heat exchanger 28 is provided with a Daipfleitung 30, through which heating steam is supplied to the sterilizing gas passing through a coil 32 heated. Below the heat exchanger 28 is a condensate trap 31/2 for discharge of the condensed steam arranged. The heat exchanger 28 has the task of to vaporize liquid sterilizing agents and to a selected elevated temperature to heat sufficient to separate the gases within the mixture prevent, for example, from ethylene oxide-Pre @ n eder Äthylenoxyd-Kchlendioxyd consists. In addition, a coenden @@ tion of the humidity in the sterilization chamber can be prevented when the cools gas and / or the liquid introduced into the same will.

Rinsing can be done by opening valves 20 and 22 Air is drawn into the chamber through the outlet port 12 and the gas through the Valve 22 is discharged to the vacuum pump.

Claims (1)

Claims 1. A method for sterilizing an object in an unclosed chamber, characterized in that the air in the chamber is displaced by a sufficient volume of a chemical sterilizing gas, to immerse the object in the gas, and that the gas during a sufficient Period of time is kept in the chamber in order to sterilize the object cause. 2. Method of sterilizing an object in an enclosed Chamber, characterized in that the air in the chamber by a sufficient Volume of a chemical sterilizing gas is displaced, which has a higher vapor density than air shows that the gas is at essentially atmospheric pressure, at least until the object is immersed in the gas, and that the gas during is held in the chamber for a sufficient period of time to allow sterilization of the object. 3. Method for sterilizing an object in a u @ schloszenem Chamber, characterized in that the air in the chamber by a sufficient Volume of a chemical sterilizing gas is displaced upwards, the one has a higher vapor density than air until the object is immersed in the gas and that the gas is maintained in the chamber for a sufficient period of time to effect the sterilization of the object. @. Method for sterilizing an object in an enclosed area Chamber, characterized in that the air in the chamber by a sufficient Volume of a chemical sterilization gas is displaced upwards, the one has a higher vapor density than air, like s D. Ethylemoxyd, until the object is in the gas is immersed and that the gas has been immersed for a sufficient period of time is held in the chamber to effect the sterilization of the object su. 5. Procedure for sterilizing a GEgen @ tandea in a box: Chamber, characterized in that the air in the chamber is sufficient Volume of a chemical sterilizing gas is displaced upwards, the one has a higher vapor density than air until the object is immersed in the gas and that the gas in the chamber has been at atmospheric for a sufficient period of time Pressure is held over or over to effect sterilization of the item. h method of sterilizing an object in an enclosed chamber, characterized in that the air in the chamber by a sufficient volume a chemical sterilizing gas is displaced to put the item in the gas immerse the gas in the chamber for a sufficient period of time is used to sterilize the object and to humidify the room while the gas is in the chamber. 7. A method of sterilizing an object in an encased area Kaiser, characterized in that the air in the chamber by a sufficient Volume of a chemical sterilizing gas is displaced upwards, the one has a higher vapor density than air until the object is immersed in the gas is that the gas is held in the chamber for a sufficient period of time, to effect the sterilization of the object and that the laser humidifies while the gas is in the chamber. 8. Method of sterilizing an object in an enclosed Chamber, characterized in that the air in the chamber by a sufficient Volume of a chemical sterilizing gas is displaced to put the item in to immerse the gas that the gas for a sufficient period of time in the Chamber is held to effect the sterilization of the article, and that the chamber substantially concurrently with the displacement of air by the gas is humidified and while the gas is in the chamber. 9. Proceeding to sterilize an object in an enclosed space inhibitor, characterized in that the air in the h @ mmer is sufficient Volume of a sterilizing gas is displaced, such as ethylene oxide, and the Geogenstand should be immersed in the gas, since # the gas has been used for a sufficient period of time inside the chamber wi @ d, @ to effect sterilization of the object, and that the r is humidified while the gas is in the chamber. 10. Procedure for sterilizing an item in an enclosed Fammer, thereby marked. because # the hammer wets up to cinem degree b @ that the @humidified @@ ft in the chamber by means of an adequate volume chemical sterilization gas @@ is displaced in order to immerse the object in the gas, and that the gas is held in the chamber for a sufficient period of time, to effect the sterilization of the item. 11. Method of sterilizing an object in an enclosed Chamber, characterized in that # the chamber @is s is humidified to a degree, da @ the humidified air in the Kommer by a sufficient volume of a chemical Sterilization g @@ it is displaced in order to immerse the object in the gas, that the gas is held in the chamber for a sufficient period of time, to effect the sterilization of the tissue stand, and because @ the lamb re-moistened while maintaining the volume of gas in the chamber. 12. Method of sterilizing an item in an enclosed Chamber, characterized in that @ humidifies the chamber to a selected degree wirtl, de @ the humidified air in the chamber by a sufficient volume of a chemical sterilization gas, such as ethylene oxide, around the object immersed in the gas and that the gas for a sufficient period of time held in the chamber to effect sterilization of the item. 13. Veriahren to sterilize an q object in an enclosed Knmmer, characterized in that the chamber humidifies up to a selected <; wheel will that the humidified air in the hammer by a sufficient volume of a chemical sterilization gas, such as ethylene oxide, around the object to immerse in the gas that the gas for a sufficient period of time in the hammer is held to effect the sterilization of the object, and that the chamber winds being humidified while the volume of gas is maintained in the chamber will. 14. Procedure for sterilizing a tied stand in a closed one hammer, characterized in that the chamber is humidified that the air is inder Chamber with a sufficient volume of a chemical sterilizing gas is displaced above, which has a higher vapor density than air, while the Object is immersed in the gas because the gas has been immersed for a sufficient period of time held in the chamber to effect the sterilization of the item, and that the chamber is humidified while the gas is in the chamber. 15. Method of sterilizing an object in an enclosed Chamber, characterized dna the chamber to a pre-selected degree is evacuated that the remaining air in the chamber by a sufficient Volume of a chemical sterilizing gas is displaced until the object is immersed in the gas and that the gas is immersed for a sufficient period of time is held in the chamber to effect sterilization of the item 3. 16. Method of sterilizing an object in an enclosed Chamber, characterized in that the chamber to a preselected degree is evacuated that the remaining air in the Kemmer by a sufficient Volume of a chemical sterilization gas is displaced, which has a higher vapor density as air until the object is immersed in the gas, and that the gas is held in the chamber for a sufficient period of time to allow sterilization of the object. 17. Procedure for sterilizing an item in an order at @@@@@ senen Chamber, characterized in that the hammer r up to a @ previously selected degree is evacuated that the air remaining in the chamber by a sufficient V @ l @ men a chemical sterilizing gas is displaced. up the subject in which GAs is immersed. da # the GAs for a sufficient time in who is hardly held to hew the st @ rilisier @@@ of the @@ enstande @, and as @ the chamber b b is humidified while @ h @ end @ich dai G 5 is in the chamber. 18. A method of sterilizing an item in an enclosed Chamber, characterized by tr @, that the @@@ mer @i; to a previously chosen one Degree eva @@ is moistened, since @ the @ i @ @@ is moisturized to a selected degree that the Air remaining in the V @ mmer by a sufficient @ volume of a chemical Sterilizing gas is displaced until the object is immersed in the gas, and that @ the gas is held in the chamber for a sufficient period of time, and the sterilization to work @ the object. 19. Sterilizer construction, characterized by a sterilization container, through a gas inlet opening at the lower end of the container and through a gas outlet at the top of the container. 20. Sterilizer construction, characterized by a sterilization container, by means of a chemical sterilizing gas applied to the lower end of the Container, and by means of a device, the air from the top of the container leads away. 2t. Sterilizer construction, characterized by a sterilization container, by a device that applies a chemical sterilizing gas to the lower end of the The container feeds, and lurch a Sinrichtunfr that on the introduction of the sterilizing gas responds to evacuate air from the top of the container.