DE1617966A1 - Process for generating negative pressure in the sterilization chamber of a steam autoclave and device for carrying out the process - Google Patents

Description

The patent attorneys λ t * 1 η η η η

Dipl. -Ing.E.Jourdan · OI I Ό OD

Dipl.-Ing.W. B eyer

Frankfurt / Main Freiherr-vom-Stein-Str.

In matters:

Aktiebolaget Electrolux
Birger Jarlsgatan 6 B
Stockholm / Sweden

Patent application

Process for generating negative pressure in the sterilization chamber of a steam autoclave and device for Implementation of the procedure.

Priority of the Swedish patent application 12 537/1965 of September 27, 1965

The present invention relates to a method for generating negative pressure in the sterilization chamber of a autoclaves operating with steam and connected to a water storage tank after sterilization.

After treatment with superheated steam, the sterilized item is { moist in the sterilization chamber of an autoclave and man therefore tends to create a negative pressure before the door is opened, which on the one hand removes the moisture causes and on the other hand, the temperature of the goods is reduced at the same time. After that it becomes common Air admitted to equalize pressure.

In the case of larger autoclaves, generating the negative pressure required for drying is not a problem, because Usually a special suction pump is available for this.

as used in the treatment of e.g.

.El W 109 / 9/21/1966 109818/1951 - 2 -

Instruments or similar objects "are intended, who are not sensitive to short-term moisture, were usually Msher without any Apparatus or devices designed to generate negative pressure, as these appeared to be dispensable, some, smaller table-top autoclaves, which are also used for the sterilization of ■ more sensitive goods, e.g. textiles, can do without the suction pump by reducing the negative pressure through direct cooling of the sterilization chamber and its content is achieved. For this purpose, once the sterilization is complete, cold water is fed into one of the sterilization chambers thermally connected cooler, which process, however, requires' that the autoclave in question is connected to an external water supply network. Finally, there are also autoclaves with a special one below the 'Container arranged in the sterilization chamber, which is connected to this in such a way that condensation water is deposited therein flows down into the container. For its cooling, the container is provided with cooling coils which have a water connection make necessary. It is true that in the last-mentioned case the condensation water can be collected and drained off before the door of the sterilization chamber is opened, but the water connection remains essential.

The object of the invention is, especially for a small one Autoclaves to find a method to use in the sterilization chamber negative pressure after the sterilization vox'gang to create. According to the invention, this object is achieved in that at the end "of the sterilization process with the aid of the In the sterilization chamber under excess pressure steam from a vacuum container and a heat conductive with it connected cooler out the air it contains * is pressed, thereupon pressure equalization with the outside atmosphere is carried out and when the cooler subsequently cools down and the vacuum container and condensation of steam under Aus-Ei W 109/21 -.9.196fο9816 / 1951 - 3 -

³ 7 '1817966

use of the associated cold pressure reduction. Water is sucked from the water storage tank into the cooler, whereby the vacuum tank is then cooled down very quickly, the steam contained therein condenses and the pressure lowering of the sterilization chamber caused by "." ■■■. /. """" Is communicated. :. ■ "; · ■" ν. ^: . ".-":. ".- · ^: _

To explain the invention in more detail, below

. a r <i _e accompanying drawings illustrated execution j "for example heschrieben drawings:

Fig. 1 shows an autoclave with associated device .- *. share, the simpler representation weighed out on a plane,

2 shows a circuit diagram of the regulating devices of the autoclave. V 'Ϊ ".'.-'

The autoclave shown in Fig. 1 is shown schematically. In a practical embodiment, the device parts are of course assembled into a compact unit. Hur- "for the sake of clarity and thus the The parts are in one plane so that it is easier to study function drawn apart. The apparatus contains a with a not shown external thermal insulation provided pressure vessel ΊΟ with a sterilization chamber 11, which is through a with Closing members 13 of a known type provided door is accessible. A line 15 is connected to the bottom -14 of the sterilization chamber 11. This stands by a line with a throttle 1? and further through a line 18 with the ' upper part of a working as a dosing tank / water container 19 in connection. This dosing container, "in turn, is Via a line 20 and a line 21 with a valve 22 connected to the lower part of a water storage tank 25.

The water reservoir is "up to level 24 with water filled. On the other hand, a line 2 $ is connected to the line 20 with a valve 26 and further a line 27 connected

Egg W 109 / 9/21/1966 1 0 9 816/1 9 5 1 - 4 _

closed. Water flows over these to one through one line 28 which leads to the steam generator 29 provided with electrical heating elements 30. The latter is connected to a line 31 connected to the sterilization chamber 11, the bottom 14 of which is inclined towards the connection of the line 31, so that in The condensation water produced in the sterilization chamber can flow back into the steam generator 29 through the line 31.

When the valve 22 is open and the valve 26 is closed, water will flow from the storage container 23 through the lines 21 and 20 through their mouths located at a level 32 into the metering container 19 and in the right leg of the line 18 'up to the same Go up high as in the reservoir 23, ie up to the level 24 ·. The shape of the line 18 is such that its highest rope 34- is located higher than the highest possible water level ir ^: the reservoir 23. _Λ

If now the valve 22 is closed and the valve 26 is opened, the amount of water in the line 33 and that in the Dosing tank 19 located above the level 32 water through the lines 20, 25, 27 in free communication with the Steam generator 29 brought.

From the line 16, behind the throttle 17, a line with a, for example, spring-loaded regulating valve 36, which also serves as a safety valve, goes out len lower part of the storage container 23. ... _t

A line 40, which contains an air filter 41, a valve and a check valve 43, is connected to the line 27 and thus to the steam generator 29. When the valve 42 is open, air can be let into the sterilization chamber 11 through the warm steam generator after the sterilization is complete *

El W 109 / 21.9.1966 _ 5 _

109816/1951

- 5 - ■ .- ■■■ ■ ^:

Requirement for "the inflow of outside air into the However, the sterilization chamber 11 is

that there is a negative pressure generated has been previously »_ This is created by using the device described hereinafter>: A line 44 has its lower mouth in the> dosing) he ehält 19 on the level 45 and extends' ■■!

upwards via a valve 46 Ms into a vacuum container 47 ■ f in to "open" inside the container at 48. A. j other line 50 starts at the bottom 49 of the vacuum container, Γ the bottom being inclined in such a way that j

occurring condensation water flows into the line 50, '' ■. " This contains a check valve 51 and opens at the top in;

a cooler 52, which in the embodiment shown \ is in the form of a jacket around the vacuum container 47 and marked with 'r ™ cooling fins, not shown, can be equipped. There is j but also the possibility of using the cooler as a coil in the,. "; ' Form inside the container. At the bottom 53 of the mantle = 52 begins a line 54 which "leads to the in the storage container opening line 39 leads. The bottom 53 of the shell 52 is for Connection of the line 54 inclined so that condensation water through this line flows down into the reservoir 23.

Parallel to the provided with regulating and safety valve 36 lines 16, 35 is a line set 55, which includes a serving for determining the start of the sterilization phase (the thermostat 57 with a sensing body 56, i Moreover, in the line 55 a steam trap 58 is arranged. The sterilization chamber has a pressure indicator 59 on the outside. The door 12 is provided with a lock 60 which prevents the door from opening as long as there is overpressure in the sterilization chamber »

The autoclave shown in the drawing requires only a relatively low power to generate the required steam pressure. Therefore, the circuit according to Pig, 2 is based on an autoclave which can be connected to a wall socket of the usual type by means of the lines 61, 62. It is switched on with the help of

El W 109 / 21.9.1966 _{109816 / 19s,,} 6-

a two-pole, manually adjustable switch 63-This the heating element 30 in the steam generator 29 live and heated. At the same time, a lamp 64 can be used to indicate that the apparatus is switched on is. As soon as the steam generator 29 reaches the predetermined temperature reached, a dependent on the temperature of the steam generator thermostat 66 responds and interrupts the power supply by a switch 65 connected to the phase line, so that the power supply is regulated as required.

If objects to be sterilized are to be placed in the autoclave, the autoclave door 12 is initially open, wherein the lock 60 in the dashed lines in J? ig. 2 "is in position 601. The lock is with a shaft which acts on the locking members in the door lock 13, e.g. via an arm 68 and a hinge lever 69. Furthermore, the shaft 67 carries a cam disk 70, which has a ' switched by lines 72, 73 into the phase line 74 Microswitch 71 actuated as well as the control body of the three aforementioned Valves 22, 26 and 4-2. These parts are set in such a way that in position 601 the door lock 13 is open is, the 'microswitch 71 is switched to "Off" and. the valves 22 and 4-2 are open, while the valve 26 closed is. The valves 22 and 26 can be replaced by a single three-way valve.

The reservoir 23 is filled with water which is distilled or can be treated in any other desired way, since the consumption, as will emerge from the following, is very low. When the reservoir 23 is filled, the water rises in the metering container 19 and further in the line 33 to level 24.

The items to be sterilized are placed in the sterilization chamber 11 and the door 12 is then closed and locked. If, then the lock 60 is switched to the position 602,

W 109 / 9/21/1966 - 7 -

109818/195 1

" ⁷ yrs. £ 17966

the Türversehluß is locked via the articulated lever 69 ': * "The microswitch 71 is switched on and the Yen tile" 22, 26 and 4-2 are switched, so that now the valves 22 and 42 are closed and the valve 26 is open In this switching position, water flows from the metering device. · ■ holder 19 through the valve 26 via the line 20, 25, 2 ?: to the steam generator 29 and the steam formed there flows. "'.- ■ ;." in the sterilization chamber 11. Simultaneously, the microswitch 71 connects a circuit designed with a motor 75 and a switching magnet 76, by means of which the duration of the sterilization phase can be preselected, to the power source /. However, the timer is also connected to the thermostat 55 dependent, the ISS the d phase line ¹ operates a switch 77 to the switch. As long as the time allotted for the sterilizing temperature has not been reached in the sterilization chamber 11, "the switch remains turned off. Only when the thermostat 5? If the correct temperature is measured, the switch 77 is turned on and the timer begins to operate. After the set time has elapsed, the timer actuates a switch 78 which closes the circuit with the electromagnet 79 - the solenoid valve 46, so that it opens and. the sterilization is interrupted.

When sterilization begins, the dated Steam generator steam flowing in via lines 15, 55 * the steam falls 58 and the pipes 57, 58, 39 the air ' from the sterilization chamber 11 to the storage container 23,, repressed. A tube 80 with a cover "81 is embedded in this, into which the air and, as a result, steam is directed " be, xiobei the steam in the water of the storage container * condensed. The pipe 80 prevents excessive boiling iia. Reservoir and thus prevents splashing of water. An in the lid 82 of the storage container 23 · Set second tube 83 with cover 84 is used for refilling of water as required. · Possibly in the sterilization chamber i1 resulting condensation flows back into the steam generator. Once the air out of the sterilization chamber is completely displaced and only steam is left to the steam

El W 109 / 21.9.1966 10 9816/1951 -8-

■ - 8 -

trap 58, this valve closes. Steam that goes along with the ^; Air passes the vapor trap, is cooled and condensed in the pipe coil 38 in the metering container 19, i

Compartment about 4-5 seconds, the pressure in the sterile "

ρ sation chamber 11 the working pressure of e.g. 3 kg / cm, and

the regulating valve 36 comes into operation. With the one-r set pressure opens the valve and thereby causes a Pressure drop in line 16 behind the throttle 1 ?. Because of the throttle 1? the pressure in the sterilization chamber 11 remains slightly higher than in the line 16, which is why the in ^ the water in the steam generator through the pipes ™ 27, 25, 20 is pushed back to the dosing container 19. This temporarily interrupts the generation of steam and the pressure drops a little. Once the regulating valve closes, the same pressure builds up again on both sides of the throttle 17, and water can reach the steam generator flow down, and as steam is generated again, it rises Pressure in the sterilization chamber 11 on again. This process repeats itself several times during the sterilization.

When the temperature in the sterilization chamber 11 and the Line 55 the value predetermined on the thermostat 57 reached, the timer is started. From this point onwards, the sterilization time set on the timer is calculated e.g. three minutes, during which the steam generator and the regulating valve work together as described above. EThen this time has elapsed, valve 4-6 opens. Immediately will the water in lines 27, 25, 20 by the steam pressure ■ in the sterilization chamber 11 is pushed back into the dosing container 19. Through the line 44 this is above the level 4-5 located water of this container in the vacuum container pressed upwards and then the steam flows out of the Sterilization chamber the same way to the vacuum container 4-7. The steam displaces air and water from the vacuum container 47

El W 109 / 9/21/1966 - 9 -

109816/1951

161796B

the. Line 50, the cooling jacket 52 and finally through line 54 to the reservoir 2 $. While the pressure in the sterilization chamber 11- drops to atmospheric pressure, the vacuum container 47 is heated by the incoming steam by so much that it only contains steam. The same applies to the jacket 52. About 30 seconds after the pressure in the sterilization chamber 11 has reached atmospheric pressure, the jacket 52, which has cooled to a little below 100 ° C. at this point in time, begins through the line 54 with water from the storage container Caused by the cold water, a further, very rapid cooling takes place, so that the steam condenses in the jacket and even more cold water flows in, which in turn cools the vacuum container 47. The negative pressure created therein sucks steam out aep : "Sterilization chamber 11 because the non-return valve 51 prevents water from being sucked in through the line 50. That in _; the vacuum created in the sterilization chamber 11 and the residual heat in the items to be sterilized and the chamber then lead to the items being completely dried. .- ■ - ..

Subsequently ⁼ the door lock is pivoted to the open position 60, where pressure equalization takes place by air · flowing in through the air filter 41, the open valve 42 ,, dais check valve 43, the line 40 and the steam generator 29, the latter of which preheats the air before this enters the sterilization chamber 11 * ^; ■ .. ".. _y , i

Simultaneously with the switching of the door lock, the valve is closed, while the valve 22 opens and lets water into the dosing container 19 for the treatment of the next filling of the sterilization chamber. The microswitch 71 is switched off, whereby the timer assumes its starting position again.

The complete program described above can be completed in approximately seven minutes, of which two minutes are drying time. Because a large part of the derived

El W 109 / 9/21/1966 ■ - - 10 -

109816/1951

Heat is captured in the water of the dosing container 19, the temperature of the larger amount of water in the storage container required for cooling the vacuum container 47 increases 23 only insignificantly during the sterilization, ■ It has been shown that it is possible to operate an autoclave according to the invention all day long to hold, without the temperature in the water tank increases to such'Werte that the work result can endanger. ·

Patent claims /

El W 109 / 21.9.1966 ■ ', 11 -

109816/1951

Claims (9)

- ■ 11. -. Claims 16 T 79.66 1. Method for generating 'negative pressure in the sterilization chamber of a working with steam and with a Water storage tank connected to the autoclave after Sterilizing, characterized in that at the end of the sterilizing process with the aid of the in the sterilization chamber (11) under excess pressure from a vacuum container (4-7) and a cooler (52) connected to it in a thermally conductive manner, the air contained therein is pressed out, thereupon pressure equalization with the outside atmosphere is carried out and with subsequent cooling of the cooler (52) and the vacuum container (4-7) and condensation of steam taking advantage of the. associated pressure reduction cold water from the water reservoir (23) in the cooler (52) is sucked, as a result of which the vacuum container (4-7) is then cooled very quickly, the vapor contained therein condenses and the resulting pressure reduction of the The sterilization chamber (11) communicates 2. The method according to claim 1 in application to one with an autoclave equipped with an evaporator, which you rc h g e k e η η ζ ei c h η e t that with the help of the in the sterilization chamber (11) At the end of the sterilization process, the steam under excess pressure presses the water out of the steam generator (29) and its supply lines (29, 27, 25, 20) will. 3. The method according to claim 2, characterized in that - k e η η ζ ei c h η e t that the from the steam generator (29) pressed back, heated during the sterilization process Water flows to a collection point (19), .from where also with the aid of the steam in the sterilization chamber (11) under excess pressure at the end of the sterilization process so much water is pressed into the vacuum container (4-7) that no more water from the collection point (19) to the steam generator (29) can flow. El W 1C9 / 21.9.1966, '098-Ιβ / 195 Iv " ^ia " 4. "Device for carrying out the procedure according to Claim 1, characterized in that that the sterilization chamber (11) of the autoclave via a starting from its lower part, during the Sterilization through a valve (46) closed line (15, 16, 18, 33, 19, 44) in connection with the vacuum container (47) stands, from the bottom of the vacuum container (47) one with. a check valve (51) provided line (50) the cooler (52) and the cooler (52) through a below the water surface of the water reservoir (23) opening line (54) is connected to this. 5 · Device according to claim 4, characterized in that the cooler (52) is used as a casing surrounds the vacuum container (47). 6. Apparatus according to claim 4, characterized ζ e i .c h η e t that the connecting line (15, 16, 18, 33r ^ 9 »44) between the sterilization chamber (11) and the vacuum tank (47) includes a water tank (19) from which by steam pressure from the side of the sterilization chamber (11) from a certain amount of water in the vacuum container (47) can be conducted. 7. Device according to claim 6, characterized in that the water container (19) is water contains, which absorbs a certain proportion of the excess heat generated during evaporation. 8. Apparatus according to claim 6, characterized in that between the water container (19) and the steam generator (29) has a line (2.0, 25, 27), such that water can flow from the water tank (19) to the steam generator (29) under the action of gravity, and that when opening the valve (46) in the line (15, 16, 18, 33 j 19 »44) between the sterilization chamber (11) and the El W 109 / 21.9.1966 -, ■ - '- 13 - 10981671951, -.13 - Vacuum container (4-7) in the latter pressed amount of water by one arranged at a certain level (4-5) Line mouth (44) is set in the water tank (19). 9. Apparatus according to claim 8 _f da durchge kenn ζ eich η et that the valve (4r6) arranged between the sterilization chamber (11) and the vacuum container (4-7) can be actuated by a timer C75) which regulates the duration of the sterilization time. - _; El W 109 / September 21, 1966 109816/1951