EP3640538B1 - Steam sterilisation device and method for assembly - Google Patents

Description

The present invention relates to a steam sterilizer according to the preamble of claim 1 and a method for assembling such a steam sterilizer according to the preamble of claim 12.

From the DE 102 60 895 A1 a steam sterilizer is known in which a steam generator with a liquid basin is arranged below a pressure vessel of the steam sterilizer. A heater is provided within the liquid basin, with which the water located in the liquid basin can be heated in order to produce steam. Typically, a target temperature of 137 ° C is envisaged for steam generation. All of the water in the liquid pool must be heated to this temperature. At the same time, the heater must always be covered with water, as an exposed heater can lead to overheating.

the U.S. 2,007,034 A describes a cylindrical steam generator in which two heating elements are arranged vertically.

the US 2010/0065414 A1 describes an arrangement for heating and for distilling water. A horizontally arranged heating element, which can optionally be configured in a spiral shape, is provided in a water basin.

the FR 2 201 747 A5 describes a steam sterilizer with a device for generating superheated steam at atmospheric pressure or slightly overpressure. The device has a boiler and a superheater. The steam emitted by the boiler is circulated in the superheater with a heating intensity that can be adjusted so that the temperature of the steam is increased to a value well above 100 ° C, generally between 100 ° C and 450 ° C.

the U.S. 2,494,654 A describes a steam generator having threaded heating elements. The steam generator is designed to supply steam to workshop equipment such as tire profile vulcanizing machines or the like.

the GB 1,090,313 A describes a device for cleaning or stripping off wall coverings. This device comprises an electrically heated water tank for supplying pressurized steam to an arrangement in which there are a number of small openings through which jets of steam emerge. The assembly forms part of an applicator having a handle hinged to the assembly such that when the applicator is moved up and down while the assembly is in contact with a panel to which steam is thereby applied, the direction of each Beam is kept constant despite varying the angular position of the handle.

The present invention is based on the object of providing a steam sterilizer which, in operation, requires less energy than the steam sterilizers known from the prior art, but at the same time can provide the same amount of steam.

This object is achieved by a steam sterilizer with the features explained below.

Such a steam sterilizer has a pressure vessel and a steam generator which can be brought into flow connection with the pressure vessel. In this way, steam that is produced in the steam generator can be transferred to the pressure vessel. The steam generator has a liquid basin and a heating element arranged in the liquid basin. The heating element is in particular arranged essentially horizontally in the liquid basin. The heating element is used to heat liquid that is held in reserve in the liquid basin in order to generate steam. For this purpose, the heating element has a heating section which serves to transfer heat to a liquid which surrounds the heating element. The heating element does not have a liquid flowing through it, but is immersed in a liquid during operation. A suitable liquid is water.

The heating section comprises the entirety of all surfaces of the heating element that are used for heat transfer. The heating section thus represents the entirety of all surface areas of the heating element that are used directly for heat transfer to the liquid in the liquid basin.

Furthermore, the heating element has a connection section with which it can be inserted into the steam generator.

According to the invention, a thread is formed in the connection section, with the aid of which the heating element can be screwed into a heating element receptacle of the steam generator. By screwing in or screwing in in this way, a far better connection is possible with heating elements that are used in steam sterilizers than by means of other connection techniques. This is because an overpressure is generated in the steam generator, so that a fluid-tight connection between the heating element and the steam generator must be pressure-tight at the same time. Typically, a sealing element such as an ordinary O-ring is also used in order to be able to produce a tight connection between the steam generator and the heating element.

In addition, the connection section of the heating element has a (virtual) axis of rotation around which the heating element can be screwed into the heating element receptacle or unscrewed from the heating element receptacle. In other words, the heating element is rotated about the axis of rotation in order to insert it into the steam generator or - for example in the case of maintenance and repair - to remove it from the steam generator.

In addition, the heating section has an underside which extends along the axis of rotation. The underside does not necessarily have to extend exactly parallel to the axis of rotation; it can also run slightly inclined to the axis of rotation (up to a maximum of about 20 degrees, in particular 0 degrees to 20 degrees, in particular 3 degrees to 15 degrees, in particular 5 degrees to 10 degrees). In addition, the heating section has an upper side. The top also extends along the axis of rotation. Like the underside, the upper side does not necessarily have to run exactly parallel to the axis of rotation. It can also extend slightly inclined to the axis of rotation (up to a maximum of about 20 degrees, in particular 0 degrees to 20 degrees, in particular 3 degrees to 15 degrees, in particular 5 degrees to 10 degrees). The angle between the lower side of the heating section and the axis of rotation and the angle between the upper side of the heating section and the axis of rotation can be the same size or different from one another.

According to the invention, the lower side of the heating section is at a greater distance from the axis of rotation than the upper side of the heating section. That is, the heating section is not aligned concentrically to the axis of rotation. Rather, it is arranged closer to a floor of the liquid basin than to a ceiling of the liquid basin.

As a result of this arrangement of the heating section eccentric with respect to the axis of rotation, it is possible to arrange the heating element closer to the bottom of the liquid container than is the case with the steam sterilizers known from the prior art. This in turn has the consequence that only a smaller volume of liquid is required in order to completely cover the heating element or the heating section with liquid. Thus, overall there is a smaller volume of liquid that has to be heated to the target temperature when generating steam. This is possible with less energy than if a larger amount of liquid had to be heated. The eccentric arrangement of the heating section with respect to the axis of rotation of the heating element thus results in energy savings when operating the steam sterilizer.

The total volume V _tot of the liquid contained in the liquid basin and to be heated to the target temperature (for example 100 to 140 ° C, in particular 110 to 139 ° C, in particular 120 to 138 ° C, in particular 130 to 137 ° C) is composed of the minimum volume V _min, which is required for operation of the heating element, and the necessary useful volume V _useful, which must be evaporated for a steam sterilization cycle (V _tot = V _min + V _payload). In order to reduce the total volume, the useful volume can be reduced, for example, which is possible by adapting the steam-consuming processes taking place during the sterilization process. In such a case, it is necessary to intervene in the control of the steam sterilizer or in the definition of the individual process steps of the steam sterilization process. This path is not taken in the present case. Rather, the solution of the objective technical problem claimed according to the invention provides for a reduction in the minimum volume V _min , in that the heating element used has a special geometry in which an axis of longitudinal extent of the heating element runs parallel offset to an axis of rotation around which the heating element is screwed into the steam generator.

Since heating elements are typically screwed or screwed into the steam generator of steam sterilizers, these heating elements have so far generally been designed to be rotationally symmetrical or concentric to an axis of rotation of the heating element. In this way, such a heating element can be screwed particularly easily into a steam generator. The solution claimed according to the invention, however, provides for a deviation from this rotationally symmetrical or concentric configuration of the heating element known from the prior art. Surprisingly, it has been shown that an assembly of the heating element by an eccentric arrangement of the heating section compared to the axis of rotation of the heating element is not made significantly more difficult, since there is typically sufficient installation space available in the liquid basin of steam sterilizers for screwing in a heating element configured in this way.

The heating element is designed as a tubular heating element with at least one heating tube. Such a heating tube has a beginning and an end, which are typically both connected to the connection section of the heating element. The heating pipe then begins at the connection section in order to adopt any geometric configuration and finally ends again at the connection section. In one variant, more than one heating pipe is provided. Even then, however, it is usually provided that the heating tubes begin and end at the connection section of the heating element. The area in which the heating tube changes its direction of extension essentially by 180 ° represents a free end of the heating section in one variant. Several such 180-degree turns of the heating tube can also together form the free end of the heating section.

In one variant, the heating tube is shaped in such a way that it has at least 2, in particular at least 3, in particular at least 4, in particular at least 5, in particular at least 6, in particular at least 7 and very particularly at least 8 sections that run parallel to one another. For example, the heating pipe can comprise 2 to 10 such parallel sections, in particular 3 to 9, in particular 4 to 8, in particular 5 to 7 such sections. All such sections together or the entire heating tube typically form the heating section if the heating element has only a single heating tube. If the heating element has a plurality of heating tubes, all surfaces of the heating tubes or surfaces of the sections of the heating tubes together form the heating section of the heating element.

In addition, a steam sterilizer with a pressure vessel and a steam generator is disclosed, which can be brought into flow connection with the pressure vessel, the steam generator having a liquid basin and a heating element arranged in the liquid basin, in particular essentially horizontally, the heating element having a heating section serving to give off heat , which in particular comprises the entirety of all surfaces of the heating element serving for heat transfer, a transition section not serving for heat dissipation and a connection section serving for connection to the steam generator, a thread being formed in the connection section, with the aid of which the heating element is inserted into a heating element receptacle of the steam generator is screwed in. It is provided that the connection section has a (virtual) axis of rotation around which a movement of the heating element for screwing into the heating element receptacle or for unscrewing from the heating element receptacle. In addition, the heating section of the heating element extends along a (virtual) longitudinal axis which runs through a central region of the heating section. However, the axis of longitudinal extension and the axis of rotation are not aligned with one another. Rather, they are offset parallel to one another. This also makes it possible to arrange the heating element closer to a bottom of the liquid container than is the case with the steam sterilizers known from the prior art.

The parallel offset provided in this further disclosure of the longitudinal extension axis of the heating element to the axis of rotation of the heating element thus results in energy savings when operating the steam sterilizer.

In a variant, the heating element is positioned as deep as possible in the liquid basin of the steam generator, this position being subject to manufacturing limitations due to the design of the liquid basin. In addition, for safe operation of the heating element it is necessary that it maintains a (small) distance from a bottom of the liquid basin of the steam generator, so that liquid, in particular water, is always present between the underside of the heating element and a lower inner side of the bottom of the liquid basin .

In one embodiment, a distance between the axis of rotation and the axis of longitudinal extent is between 1 cm and 10 cm, in particular between 2 cm and 9 cm, in particular between 3 cm and 8 cm, in particular between 4 cm and 7 cm, in particular between 5 cm and 6 cm .

In one embodiment, a difference between the distance between the bottom and the axis of rotation and the distance between the top and the axis of rotation is between 1 cm and 10 cm, in particular between 2 cm and 9 cm, in particular between 3 cm and 8 cm, in particular between 4 cm and 7 cm, in particular between 5 cm and 6 cm.

In a variant, the heating section has a first end and a second end. The first end is connected directly or indirectly to the connection section. In contrast, the second end is a free end, that is to say an end that is not connected to any other section of the heating element. For example, the free end can be designed in the form of a 180 degree curve of a region of the heating section in order to bring about a change in direction of individual elements of the heating section.

In one variant, the heating element has a transition section that does not serve to give off heat. The transition section is arranged between the connection section and the heating section. At the same time, the transition section is connected both to the heating section and to the connection section. In this variant, there is thus an indirect connection between the heating section and the connection section of the heating element. In this variant, the transition section runs at an angle both in relation to the axis of rotation and in relation to a direction of longitudinal extension of the upper side of the heating section. By means of such a transition section, a parallel offset of the heating section in relation to the axis of rotation can thus be brought about in a particularly simple manner, so that the heating section can be arranged particularly easily eccentric to the axis of rotation by means of such a transition section.

In one variant, the underside of the heating section runs essentially parallel to a bottom of the liquid basin. This simplifies the installation of the heating element and the later operation of the steam sterilizer. In a variant, the bottom of the liquid basin has a slight incline in order to enable the liquid basin to be emptied particularly easily. The term "essentially parallel" is to be understood as meaning both an arrangement that simulates such an inclination of the bottom of the liquid basin and an arrangement in which the heating element runs horizontally while the bottom of the liquid basin has a slight inclination relative to the horizontal .

The top of the heating section can in principle run above the axis of rotation. In this case, however, the top of the heating section in any case protrudes less far upward relative to the axis of rotation than the bottom of the heating section protrudes downward relative to the axis of rotation. In a variant it is provided that in particular the entire upper side of the heating section extends below the axis of rotation. In this variant, the heating element can be arranged particularly deep in the liquid basin.

In one variant, an envelope of the heating section extends along a (virtual) longitudinal axis. This longitudinal axis is typically identical to the longitudinal axis, which runs through a central region of the heating section. In this variant, the longitudinal axis runs through the center of gravity of the cross section of the envelope. It is further provided that the axis of rotation and the axis of longitudinal extent run parallel offset to one another. The envelope can also be referred to as a three-dimensional envelope or as a three-dimensional envelope curve. they describes a virtual three-dimensional figure that surrounds the entire heating section like a cone jacket or a cylinder jacket, and its inside rests against the outer surface of the heating section. The cross section of the envelope typically has a circular or elliptical base area. The center of gravity of such a base area is typically in the center of the base area. In this variant, the longitudinal axis therefore typically runs through the center of the cross section of the envelope.

In one embodiment, the transition section runs between the connection section and the heating section. The transition section extends along a transition section axis which runs both at an angle to the axis of rotation and at an angle to the axis of longitudinal extension. In other words, the transition section axis intersects the axis of rotation and the axis of longitudinal extension. In one variant, an angle between the transition section axis and the axis of rotation or between the transition section axis and the longitudinal extension axis is between 5 ° and 30 °, in particular between 10 ° and 25 °, in particular between 15 and 20 °. Since the transition section itself does not serve to give off heat to a liquid which surrounds the heating element, the transition section does not have to be completely covered by liquid. It is only important for the function of the heating element that the heating section of the heating element is completely covered by liquid when the steam sterilizer is in operation.

So that the heating element is arranged closer to a bottom of the liquid basin, the axis of longitudinal extent must be arranged lower than the axis of rotation. In one embodiment, the axis of longitudinal extent runs exactly below the axis of rotation. The heating section of the heating element is then typically arranged in its lowest possible position, so that the total volume of the liquid to be heated can be reduced to a minimum in order to ensure safe operation of the heating element.

In one variant, the longitudinal axis of extent of the heating element or the underside of the heating section runs essentially parallel to a bottom of the liquid basin. A substantially parallel alignment exists when the longitudinal axis or the underside of the heating section is inclined by a maximum of 3 degrees, in particular by a maximum of 0.5 degrees to 2.5 degrees, in particular by a maximum of 1 degree to 2 degrees, to the floor. This means that the heating section of the heating element in this variant runs parallel or inclined by up to 3 degrees to the bottom of the liquid basin. Such a substantially parallel arrangement of the heating section to the bottom of the liquid basin is preferred, since then a substantially uniformly high liquid level in the liquid basin ensures that that the heating section of the heating element is immersed substantially uniformly deep into the liquid in the liquid basin. In this embodiment, it is particularly assumed that the bottom of the liquid basin runs essentially horizontally. The floor then runs essentially horizontally when it is inclined relative to the horizontal by a maximum of 3 degrees, in particular by a maximum of 0.5 degrees to 2.5 degrees, in particular by a maximum of 1 degree to 2 degrees. For example, an inclination in a range of 0.5 degrees to 3 degrees can ensure that the water in the liquid basin automatically collects in an area of the liquid gas basin by providing an emptying nozzle or drain for the liquid basin.

In one variant, the longitudinal axis of extent of the heating element or the underside of the heating section runs exactly parallel to a bottom of the liquid basin. In a variant, the bottom of the liquid basin runs exactly horizontally.

In one variant, the heating element has a positioning element. When the heating element is screwed in, this positioning element ensures automatic positioning of the heating element in the intended installation position, that is to say in particular with a heating section arranged as low as possible. The positioning element strikes a stop when the heating element is in the desired installation position. The positioning element then prevents further screwing in of the heating element, that is to say a further rotational movement of the heating element in the installation direction. The positioning element can, for example, be designed as a limiting pin which strikes a stop when the heating element is in the desired installation position.

Regardless of whether or not a positioning element is provided, in one variant the heating element is locked in its installed position by a locking means, so that it can only be rotated out of its installed position again after the locking means has been released. In a preferred embodiment, the positioning element and the locking means can interact with one another and effect automatic positioning with subsequent locking of the heating element.

One aspect of the present invention relates to a method for assembling a steam sterilizer according to the previous explanations. As stated, the steam sterilizer has a pressure vessel and a steam generator. This steam generator can be brought into flow connection with the pressure vessel. The steam generator has a liquid basin and a heating element which is arranged in the liquid basin. The heating element has a heating section and a Connection section. The heating section is used to give off heat to a liquid that surrounds the heating element in the liquid basin. The heating section comprises the entirety of all surfaces of the heating element provided for heat transfer, that is to say all those surfaces which directly ensure heat transfer into a liquid contained in the liquid basin. The connection section is used to connect the heating element to the steam generator. According to the invention, a thread is formed in the connection section for this purpose.

The method claimed according to the invention is also characterized in that the heating element for assembly is screwed into a heating element receptacle of the steam generator by means of the thread around an axis of rotation of the connection section. This screwing in takes place until a positioning element prevents the heating element from being screwed in further and the connection section is fluid-tightly connected to the heating element receptacle and an underside of the heating section extending along the axis of rotation is below the axis of rotation and is further spaced from the axis of rotation than a Top of the heating section.

As already stated above, this positioning element can be, for example, a stop element which, when screwed in, strikes a stop when the desired or optimal installation position has been reached. In addition, a locking means can be provided with which the heating element is locked in the desired position after it has been screwed in, in order to avoid an undesired change in position of the heating element.

In addition, an alternative method for assembling a steam sterilizer according to the previous explanations is disclosed. As stated, the steam sterilizer has a pressure vessel and a steam generator. This steam generator can be brought into flow connection with the pressure vessel. The steam generator has a liquid basin and a heating element which is arranged in the liquid basin. The heating element has a heating section, a transition section and a connection section. The heating section is used to give off heat to a liquid that surrounds the heating element in the liquid basin. In particular, the heating section comprises the entirety of all surfaces of the heating element provided for heat transfer. The transition section, on the other hand, does not serve to transfer heat to such a liquid. The connection section is used to connect the heating element to the steam generator. For this purpose, a thread is formed in the connection section.

The alternative method is characterized in that the heating element for assembly is screwed into a heating element receptacle of the steam generator by means of the thread around an axis of rotation of the connection section. This screwing in takes place until the connection section is fluid-tightly connected to the heating element receptacle and at the same time a longitudinal axis of the heating element, along which the heating section extends and which runs parallel to the axis of rotation, is located below the axis of rotation. Such an assembly ensures that the heating section of the heating element is arranged lower than the axis of rotation of the heating element and is thus closer to a bottom of the liquid basin than a heating element that is constructed rotationally symmetrical about an axis of rotation.

In one variant, the heating element is screwed into the heating element receptacle until the axis of longitudinal extent or the underside of the heating section is exactly below the axis of rotation.

All of the configurations, aspects and variants of the steam sterilizers explained above can be combined with one another in any desired manner and transferred to the described methods in any desired combination. The different variants, aspects and configurations of the methods can also be combined with one another in any way and transferred to the other methods and to the steam sterilizers described.

Figur 1A

eine schematische Längsschnittansicht durch einen Dampfsterilisator des Stands der Technik;

Figur 1B

eine schematische Längsschnittansicht durch ein Ausführungsbeispiel eines Dampfsterilisators;

Figur 2A

eine vergrößerte schematische Seitenansicht des Heizelements des Dampfsterilisators der Figur 1A (Stand der Technik);

Figur 2B

eine vergrößerte schematische Seitenansicht des Heizelements des Dampfsterilisators der der Figur 1B;

Figur 2C

eine schematische Seitenansicht eines weiteren Heizelements eines Dampfsterilisators und

Figur 3

eine schematische Querschnittsansicht durch das Heizelement der Figur 2B bzw. der Figur 2C im Bereich des jeweiligen Heizabschnitts.

Further details of aspects of the present invention are explained in more detail using an exemplary embodiment and corresponding figures. Show it:

Figure 1A

a schematic longitudinal sectional view through a steam sterilizer of the prior art;

Figure 1B

a schematic longitudinal sectional view through an embodiment of a steam sterilizer;

Figure 2A

an enlarged schematic side view of the heating element of the steam sterilizer of FIG Figure 1A (State of the art);

Figure 2B

an enlarged schematic side view of the heating element of the steam sterilizer of FIG Figure 1B ;

Figure 2C

a schematic side view of a further heating element of a steam sterilizer and

Figure 3

a schematic cross-sectional view through the heating element of FIG Figure 2B or the Figure 2C in the area of the respective heating section.

the Figure 1A shows a steam sterilizer 1 known from the prior art with a pressure vessel 2 and a steam generator 3, which surrounds the pressure vessel 2 in sections in a jacket-like manner. On an underside of the pressure vessel 2, a liquid tank 4 of the steam generator 3 is arranged, in which water for steam generation is kept in stock. In this case, a tubular heating element 5 is arranged in the liquid basin 4, which is used to heat the water 6 contained in the liquid basin 4.

In order for the tubular heating element 5 to function reliably, it must be completely covered with water 6. The minimum liquid level in the liquid basin 4 is indicated by the dashed line denoted by V _min.

the Figure 1B shows an embodiment of a steam sterilizer 10. This steam sterilizer 10 also has a pressure vessel 20 and a steam generator 30, which surrounds the pressure vessel 20 in sections like a jacket. A liquid tank 40 of the steam generator 30 is arranged on an underside of the pressure vessel 20. In this liquid basin 40 there is a tubular heating element 50 which serves as a heating element. This tubular heating element 50 is used while the steam sterilizer is in operation to evaporate water 60 that is located in the liquid basin 4, so that the steam then passes through a device shown in the schematic illustration in FIG Figure 1B Line not shown in detail from the steam generator 30 can be passed into the interior of the pressure vessel 20.

The tubular heater 50 is stepped along its longitudinal axis; it has a step-like course. As a result, the tubular heating element 50 can be arranged closer to a lower floor 41 of the liquid basin 40 than is the case with the heating elements known from the prior art. As a result, a lower minimum water volume V _{min is} required in order to be able to operate the tubular heating element 50 safely. As a result of this lower water volume V _min , the total volume of the water to be heated in the liquid basin 40 by the tubular heating element 50 is significantly lower than in the case of the steam sterilizers known from the prior art. As a result, less energy is required to heat or partially evaporate this water. Thus, the steam sterilizer 10 can be operated with a lower energy input than, for example, the steam sterilizer 1, although the amount of steam generated in the steam generator 30 corresponds exactly to the amount that is also used in the steam generator 3 of the steam sterilizer 1 (cf. Figure 1A ) can be generated.

the Figure 2A shows an enlarged side view of the tubular heater 5 of FIG Figure 1A . This tubular heating element 5 has an axis of rotation RA around which it can be rotated in order to be screwed into the steam generator 3 in the area of the liquid basin 4. The tubular heating element 5 is constructed essentially rotationally symmetrical about the axis of rotation RA.

the Figure 2B FIG. 11 shows an enlarged side view of the tubular heating element 50 of the steam sterilizer 10 of FIG Figure 1B . This tubular heating element 50 also has an axis of rotation R which runs centrally through a threaded plug 51 which serves as a connection section. A thread 52 is provided on this threaded plug 51, with which the tubular heating element 50 can be screwed into a tubular heating element receptacle provided for this purpose in the area of the liquid basin 40 of the steam generator 30. A transition section 53 runs obliquely downward from the connection section 51 and then merges into a straight heating section 54 of the tubular heating element 50.

This heating section 54 of the tubular heating element 50 extends along a longitudinal axis L which runs approximately centrally within the heating section 54. The heating section 54 has four sub-sections 55 of a heating pipe, which are connected to one another in the manner of windings and which run parallel to one another in sections. The heating section comprises all surfaces of the tubular heating body 50 which are provided for heat transfer.

The transition section 53 extends along a transition section axis U, which intersects both the axis of rotation R and the longitudinal extension axis L at an angle α, which in the embodiment of the tubular heater 50 of Figure 2B is around 15 °.

The axis of longitudinal extension L is offset parallel to the axis of rotation R due to the transition section 53. As a result of this parallel offset between the axis of rotation R and the axis of longitudinal extent L, a stepped structure of the tubular heating element 50 is achieved, in which the heating section 54 is no longer aligned with the axis of rotation. This has the consequence that an underside 540 of the heating section 54 lies deeper below the axis of rotation R than one Upper side 541 of the heating section 54 is above the axis of rotation. In other words, the lower side 540 of the heating section 54 is spaced further from the axis of rotation R than the upper side 541 of the heating section 54. In the exemplary embodiment of FIG Figure 2B the top side 541 of the heating section 54 is also completely below the axis of rotation R of the tubular heating element 50.

In this way it is possible to arrange the heating section 54 further outside a center of the tubular heating element 50 defined by the axis of rotation than is the case with the tubular heating elements known from the prior art. It is thus possible to arrange the heating section 54 as a whole below the axis of rotation R and thus lower than the heating sections of the tubular heating elements known from the prior art. This means that less water is required to completely cover the heating section 54 if it is arranged in a liquid basin of the same size as a conventional tubular heating element. Less water then has to be heated in order to generate steam from the water by means of the tubular heating element 50.

A comparable effect can be found with that in the Figure 2C Achieve shown tubular heater 50, which represents a further embodiment of a tubular heater for a steam sterilizer. The same elements are denoted by the same reference symbols as in the previous figures.

The tubular heater 50 of the Figure 2C also has a threaded plug 51 with a thread 52 and a heating section 54, which on its in the Figure 2C The side shown on the left is connected to the threaded plug 51. The heating section 54 comprises all surfaces of the tubular heating element 50 which are used for heat transfer and thus ensure heat transfer into a liquid (in particular water) which surrounds the tubular heating element 50 in a liquid basin of a steam sterilizer.

The tubular heating element 50 again has an axis of rotation R around which the tubular heating element 50 can be screwed with its thread 52 into a corresponding tubular heating element receptacle.

An underside 540 of the heating section 54 is spaced further from the axis of rotation R than an upper side 541 of the heating section 54. In other words, the heating section 54 of the tubular heating element 50 and the rotating axis R of the tubular heating element 50 are arranged not concentrically with one another, but rather eccentrically. Such a configuration also results in a lowered arrangement of the heating section 54 of the tubular heating element 50 achieved, whereby a minimum liquid volume that is required for the intended operation of the tubular heater 50 is smaller than in the solutions known from the prior art.

In this embodiment of the Figure 2C the upper side 541 of the heating section 54 is not continuously below the axis of rotation R. Nevertheless, it is always arranged closer to the axis of rotation R than the lower side 540 of the heating section 54.

On the in the Figure 2C The side of the heating section 54 shown on the right is not connected to any other element of the tubular heating element 50, but has a free end 542. Here, a heating tube of the heating element makes a 180-degree curve in order to change the direction of the course of the heating tube.

the Figure 3 FIG. 11 shows a schematic cross-sectional view through the tubular heating element 50 of FIG Figure 2B or the Figure 2C in the area of the heating section 54 of the respective tubular heating element 50. The subsections 55 of the heating tube of the tubular heating element 50 can be clearly seen.

The entire heating tube with its sub-sections 55 provides the entire surfaces of the heating section 54 provided for heat transfer. A (virtual) envelope 543 is placed around the heating tube of the heating section 54. The envelope 543 has the shape of a cylinder jacket (it is open at the free end 542 of the heating section 54; compare FIG Figure 2C ) and extends on an outside of the surface of the heating portion 54.

The envelope 543 encloses an elliptical base area 544 in its interior. The center of gravity of this base area 544 lies in the center of the base area 544. A longitudinal axis L of the heating section 54 runs through this center of gravity. This results in an acentric alignment of the heating section 54 or the longitudinal axis L of the heating section 54 in relation to the axis of rotation R. Consequently, it is possible to arrange the heating tube with its sub-sections 55 deeper in the liquid basin of a steam sterilizer than with the prior art known solutions is the case.

Claims (12)

1. Steam sterilizer having a pressure vessel (20) and having a steam generator (30) which can be connected in terms of flow to the pressure vessel (20), wherein the steam generator (30) has a liquid basin (40) and a heating element (50) which is arranged in the liquid basin (40), wherein the heating element (50) has a heating section (54), which serves for heat output and comprises the entirety of all the surfaces of the heating element (50) that serve for heat transfer, and has a connection section (51), which serves for connection to the steam generator (30),
   characterized
   in that a thread (52) is formed in the connection section (51), with the aid of which thread the heating element (50) is screwed into a heating element receiving part of the steam generator (30), in that the connection section (51) has an axis of rotation (R) about which a movement of the heating element (50) for screwing into the heating element receiving part or for screwing out of the heating element receiving part is realized, in that a bottom side (540), extending along the axis of rotation (R), of the heating section (54) is spaced apart further from the axis of rotation than a top side (541), extending along the axis of rotation (R), of the heating section (54), and in that the heating element (50) is in the form of a tubular heater with at least one heating tube.
2. Steam sterilizer according to Claim 1, wherein the heating section (54) has a first end and a second end, wherein the first end is connected to the connection section (51) and the second end is a free end (542).
3. Steam sterilizer according to Claim 1 or 2, wherein the heating element (50) has a transition section (53) which does not serve for heat output and which is arranged between the connection section (51) and the heating section (54) and which is connected to the connection section (51) and the heating section (54) and which extends at an angle both in relation to the axis of rotation (R) and in relation to a direction of longitudinal extent of the top side (541) of the heating section (54).
4. Steam sterilizer according to one of the preceding claims, wherein the bottom side (540) of the heating section (54) extends substantially parallel to a base (41) of the liquid basin (40).
5. Steam sterilizer according to one of the preceding claims, wherein the top side (541) of the heating section (54) is arranged below the axis of rotation (R) .
6. Steam sterilizer according to one of the preceding claims, wherein an envelope (543) of the heating section (54) extends along an axis of longitudinal extent (L) which, in the cross section of the heating section (54), extends through the centre of mass of a surface (544) enclosed by the envelope (543), wherein the axis of rotation (R) and the axis of longitudinal extent (L) extend in a parallel offset manner with respect to one another.
7. Steam sterilizer according to Claim 6, wherein the axis of longitudinal extent (L) of the envelope (543) of the heating section (54) of the heating element (50) extends just below the axis of rotation (R).
8. Steam sterilizer according to Claim 6 or 7, wherein the axis of longitudinal extent (L) of the envelope (543) of the heating section (54) of the heating element (50) extends substantially parallel to a base (41) of the liquid basin (40).
9. Steam sterilizer according to one of Claims 6 to 8, wherein the heating element (50) has a transition section (53) which does not serve for heat output and which is arranged between the connection section (51) and the heating section (54) and which is connected to the connection section (51) and the heating section (54) and which extends at an angle both in relation to the axis of rotation (R) and in relation to the axis of longitudinal extent (L).
10. Steam sterilizer according to one of the preceding claims, wherein the heating element (50) has a positioning element which, when the heating element (50) is being screwed in, abuts against a stop when the heating element (50) is in the desired installation position, and thus provides for automatic positioning of the heating element (50) in the intended installation position.
11. Steam sterilizer according to one of the preceding claims, wherein the heating element (50) has at least two sections (55) which extend parallel to one another.
12. Method for assembling a steam sterilizer according to one of the preceding claims,
    characterized
    in that, by means of the thread (52), the heating element (50) is screwed into a heating element receiving part of the steam generator (30) about an axis of rotation (R) of the connection section (51) until a positioning element prevents further screwing-in of the heating element (50) and the connection section (51) is connected to the heating element receiving part in a fluid-tight manner and a bottom side (540) of the heating section is situated below the axis of rotation (R) and, in the process, is spaced apart further from the axis of rotation (R) than a top side (541) of the heating section (53).

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