Patent Description:
In the production and processing of various products it is often necessary to remove a fluid from a closed process system or to add fluid to the system. The fluid may be, for example, a liquid. Such a need exists for example in the production and processing of biopharmaceuticals, pharmaceuticals, or other biotechnology applications during which a production process is carried out in process vessels. Such a need may also exist, for example, in the production of food,paints or chemicals, to name only a few. The problem with the transfer of a fluid is the need for the adding or removal of the fluid to be done in an aseptic, hygienic, and/or sterile manner.

From <CIT> there is known a method for seling and severing a subsea pipeline. The method include piercing the pipe to form an opening, injecting sealant material through the opening into the pipe to form a fluid-tight seal, and cutting the pipe through the seal to form sealed cut ends.

<CIT> relates to a device for processing hollow bodies, the device comprising: a device body; a fixing member connected to the device body to insert the hollow bodies into the inner part; a compression member including a compression plate provided to be moved to the device body for compressing the hollow bodies; and a cutting member provided to be moved to the device body for cutting the hollow bodies and including a cutting plate positioned to be adjacent to the compression plate.

From <CIT> there is known a flexible conduit, comprising a plastically deformable sleeve. The plastically deformable sleeve surrounds and is attached to the conduit. The conduit may be a tube or a hose. By a pressure exerted on the sleeve, the sleeve and the hose or the conduit are deformed in order to seal off the conduit, while by applying further pressure to the sleeve, the sleeve and the conduit are severed, the conduit being substantially fluid-tight in the compressed region. The compressing and the separating of the sleeve and the conduit are done at the same time.

From the document US RE <NUM>,<NUM> E (reissue of <CIT>) there is known a hand tool which is used to form a fluid-tight separating closure of a conduit with a sleeve surrounding the conduit. The hand tool has two oppositely situated jaws, between which the conduit with the sleeve is positioned. A first tool jaw has a cutting tool, which is oriented in the direction of the opposite second tool jaw. Webs are provided on either side of the cutting tool. If the tool jaws are moved toward each other, the sleeve and the hose will be sliced and compressed. A comparable design of a hand tool is known from the document <CIT>.

The concept known from these documents is transferred to an electrohydraulic tool, as is known from <CIT>.

Starting from this prior art, the problem which the present invention proposes to solve is to indicate a method as well as a device for the forming of a fluid-tight separating closure of a conduit with a sleeve surrounding the conduit by which an increased process safety can be accomplished.

This problem is solved by a method for forming of a fluid-tight separating closure of a conduit according to the independent method claim and by a device with the features of independent apparatus claim.

Advantageous embodiments and modifications of the method and the device are the subject matter of the dependent claims.

According to the invention a method is provided for the forming of a fluid-tight separating closure of a conduit involving the following steps:.

Thanks to this method according to the invention, a better process safety is achieved, since a severing of the closure in a compressed region substantially only occurs when a substantially fluid-tight separating closure has already been achieved. Therefore, no germs, particles, contaminants, etc., can be introduced by the severing tool into the conduit during the severing. On the other hand, contamination of the surroundings by a fluid escaping from the conduit is also prevented, since the fluid located in the conduit is forced out of the compressed region and from the closure by the compression, which occurs substantially prior to the severing.

The described method can be applied in particular in the production and processing of biopharmaceuticals, pharmaceuticals, or other biotechnology applications during which a production process is carried out in process vessels.

The severing of the closure is preferably performed after the compressing of the sleeve. The severing is performed using a severing tool that preferably has a blade for severing. During severing a contact line between the severing tool and the sleeve is shorter than an obtained severing edge of the sleeve. This condition is preferably fulfilled during the entire severing.

The contact line is where the severing tool is in contact with the surface of the sleeve at a certain time. That is, during severing the contact line can vary in position and/or in length. For example, if a plane blade is placed onto a surface such that during severing the entire blade is in contact with the surface at the same time, the contact line extends along the entire edge of the blade. In a different example, the contact line can be significantly smaller than the extension of the blade. In particular, the contact line can be a single contact point. Therein, a point is considered a very short line. For example, in cutting a piece of paper by a blade there is usually only a single contact point between the blade and the paper.

The cutting line according to the present invention does not have to be continuous. It is even preferred that contact between the severing tool and the sleeve is first established at the outmost portions of the sleeve such that at the beginning of the severing there are two short sections of the contact line that are spaced apart from each other. In case the contact line is not continuous, the length of the contact line is the sum of all parts of the contact line.

The severing edge is the result of the severing. After the sleeve has been severed by the severing tool, the remaining part of the sleeve has an edge that has not been there before the severing. This edge is considered the severing edge. The severing edge is the edge of the severed sleeve on that side of the sleeve from where the severing tool has been brought into contact with the sleeve. Since the sleeve is separated into at least two parts it is noted that both parts of the sleeve can equally be considered for determining the severing edge. This is due to the fact that by severing a sleeve into two pieces the obtained edges on the two parts correspond to each other and, in particular, have the same length.

According to the present invention the contact line is shorter than the obtained severing edge. That means that the severing is not performed by placing a blade onto the surface such that the entire blade is in contact with the surface and the sleeve is cut by equally applying a pressure onto the blade. Such a cutting would require a very high force and would not be sufficiently reproducible. Instead, different parts of the severing edge are obtained at different times of the severing. That way, only part of the sleeve has to be cut at the same time. Thus, a lower force is required to be applied. This can reduce the size of the used device because, for example, lower hydraulic pressure is sufficient for moving the severing tool. Providing high hydraulic pressures usually requires particularly heavy devices. Thus, weight can be saved so that the device can be configured as a mobile device. Also, a lower force requires less energy such that energy can be saved. Further, with a reduced required minimum force for severing the sleeve can be severed particularly fast. This is due to the fact that it a small minimum force can easily be exceeded. If a force is applied that is larger than necessary, a particularly fast severing can be achieved. Also, more reliable and reproducible results can be obtained if only a small force is required for severing.

According to an advantageous embodiment of the method a length of the contact line is at most <NUM> % of a length of the obtained severing edge.

The described condition is preferably fulfilled during the entire severing. By restricting the length of the contact line to at most <NUM> % of the severing edge the above described effect can be achieved to an extent that is sufficient for many applications. Above <NUM> % the situation might be too close to bringing an entire blade into contact with the surface. It is even more preferred that a length of the contact line is at most <NUM> % of a length of the obtained severing edge.

It is even possible that the contact line is much smaller than the severing edge. The contact line can even be a single contact point, that is a very short contact line. It is thus preferred that a length of the contact line is at most <NUM> % of a length of the obtained severing edge, more preferred only <NUM> %. This condition is also preferably fulfilled during the entire severing. By having such a short contact line only, the severing is not performed all at once. In contrast, one part of the severing edge is obtained after the other. Thereby, the force required for severing can be reduced significantly.

According to another advantageous embodiment of the method a central portion of the severing edge is formed at an end of the severing.

In this embodiment the severing begins at the outmost portions of the sleeve. After these portions have been severed, the central portion of the sleeve is severed. This way, the cutting edge is obtained starting from two sides of the sleeve, wherein two branches of the cutting edge both spread towards the central portion of the sleeve. The severing is complete when the two branches meet and merge together in the central portion. By having two branches of the cutting edge, a particularly small force can be applied in a symmetric manner. Thus, a small fore can be used particularly efficiently. Also, the severing can be particularly fast because two branches of the severing edge are obtained simultaneously.

The described way of severing can be achieved, for example, with a plane blade and a curved die. The sleeve is compressed into the die so as to adapt the curved shape of the die. The die is preferably curved such that after compressing the sleeve the outmost portions of the sleeve are closer to the blade than the central portion of the sleeve. If the blade is moved towards the sleeve, the outmost portions of the sleeve are severed first and the central portion last. Alternatively, the sleeve could be compressed so as to have a plane surface, which can be severed by a curved blade.

According to another advantageous embodiment of the method the stamp and the severing tool are moved relative to the die independently of each other.

Due to the independent movement of the stamp and the severing tool the compressing and severing of the sleeve can be performed independently. This is advantageous because this way the compressing can be terminated before the severing begins such that a contamination of substances within the conduit can be ruled out.

According to another advantageous embodiment of the method the severing is done by cutting or punching.

A severing of the closure in the compressed region occurs preferably by cutting or punching. Severing by means of a cutting process has the advantage that no waste products are produced. If the conduit and the sleeve surrounding the conduit are bodies of relatively large diameter, it is advantageous, but not necessary, to perform the severing by punching. If the severing of the closure is done in a compressed region by punching, it is advantageous for the stamped part produced by punching to be taken to a catching container.

According to another advantageous embodiment of the method the compressing is limited such that the compressed region of the sleeve acquires a predefined shape.

If the force applied to the sleeve during compressing is too high, the sleeve and/or the conduit might break or burst. Thereby, the conduit might be separated into two pieces as required; however, a contamination of substances within the conduit cannot be ruled out. Thus, a breaking or bursting of the sleeve and/or of the conduit is supposed to be avoided. This can be achieved by limiting the compressing of the sleeve. For example, a device used for performing the described method may comprise a stop for the stamp. That way, there is a predefined minimum space for the sleeve and the conduit, regardless of how large a force is used for compression. If the sleeve and the conduit are compressed into this predefined space, the sleeve acquires a predefined shape that corresponds to the predefined space. With the sleeve having the predefined space, also the severing can be performed with a predefined contact between the sleeve and the severing tool. Thereby, a particularly high reproducibility is achievable.

A further aspect of the invention relates to a device for forming a fluid-tight separating closure of a conduit with a sleeve surrounding the conduit as defined in claim <NUM>.

The device is preferably configured for performing the described method. The described method is preferably performed using the described device. The features and advantages described for the method can be transferred to the described device, and vice versa.

With the stamp and the severing tool being movable independently of each other, the above described condition can easily be fulfilled that the contact line between the severing tool and the sleeve is shorter than the obtained severing edge. If the die and the severing tool were moved simultaneously, the entire severing tool would be likely to be brought into contact with the surface. That way, the advantages of the described method could not be achieved.

According to an advantageous embodiment of the device the severing tool is a knife or a punching stamp.

According to another advantageous embodiment of the device the severing tool is arranged within the stamp.

In this embodiment the severing tool can be accommodated within the stamp such that the device can be particularly compact and small. Also, compressing and severing can be performed particularly efficiently if the severing tool is arranged within the stamp because after compressing the stamp can remain in place, while the severing tool is used to sever the sleeve. Thereby, the stamp can hold the sleeve in place such that no further holding means are necessary.

According to another advantageous embodiment of the device the severing tool and the stamp jointly form a compression surface for compressing the sleeve, and wherein the severing tool can be moved so as to protrude from the compression surface for severing the closure.

The severing tool and the stamp jointly form the compression surface for compressing the sleeve in a compression state. Therein, the compression tool is received within the stamp and does not protrude from the compression surface. For severing the sleeve the severing tool can be moved out of the compression state such as to protrude from the compression surface. This way, the device can be particularly compact and small. With the severing tool and the stamp jointly forming the compression surface, there is no gap for the severing tool within the stamp. Such a gap would be disadvantageous for compression. A smooth surface without any gaps is best for compressing the sleeve. Further, the configuration according to the present embodiment is particularly save because the severing tool can be hidden when not used for severing.

According to another advantageous embodiment of the device the severing tool has a blade with a shape that has at least one of the following features:.

The features listed above can be combined with each other in any manner. Particularly preferred is the embodiment in which the severing tool has a blade that has the shape of a straight line. Therein, the blade preferably has no further features such as protrusions or recesses. Also, it is particularly preferred that the blade has the shape of a curved line with a protruding central region as the only shape feature.

According to another advantageous embodiment of the device the die has a curved receiving surface for receiving the sleeve.

In this embodiment the above described condition that during severing the contact line between the severing tool and the sleeve is shorter than an obtained severing edge of the sleeve can be fulfilled easily because the sleeve is compressed such that the outmost portions of the sleeve are closer to the severing tool than the central portion of the sleeve. That way the outmost portions of the sleeve are severed first and the central portion last.

In this embodiment it is further facilitated that during severing the contact line between the severing tool and the sleeve is kept shorter than the obtained severing edge of the sleeve. If the receiving surface and the blade would have matching shapes, the contact line would likely be particularly long.

According to another advantageous embodiment the device further comprises a stop for limiting the movement of the die and the stamp relative to each other.

According to another advantageous embodiment the device further comprises a first hydraulic cylinder for moving the stamp and a second hydraulic cylinder for moving the severing tool.

It is preferred that the first hydraulic cylinder and the second hydraulic cylinder are arranged together in a hydraulic cylinder unit. In particular, the first hydraulic cylinder can be arranged so as to surround the second hydraulic cylinder in a concentric manner. Alternatively, the second hydraulic cylinder can be arranged so as to surround the first hydraulic cylinder in a concentric manner. The first hydraulic cylinder and/or the second hydraulic cylinder are preferably configured as telescope cylinders.

The first hydraulic cylinder and the second hydraulic cylinder are preferably configured so as to be usable independently of each other so that the stamp and the severing tool can be moved independently of each other.

According to another advantageous embodiment of the device the die is configured in a pivotable manner.

In this embodiment the device can be particularly small, in particular in view of a distance between the die and the stamp. Having a small distance between the die and the stamp is advantageous because the smaller this distance is, the more stable the device can be. In particular when high forces are applied it is advantageous that the device is as compact as possible. Otherwise, large lever arms could increase the applied forces even further and could, eventually, result in a damage of the device. The required minimum distance between the die and the stamp is basically a result of the diameter of the sleeve before the compressing. However, it might not be sufficient to have the die and the stamp spaced apart from each other at a distance equal to the diameter of the sleeve before compressing. This is due to the fact that it must be possible to place the sleeve in between the die and the stamp. The conduit with the sleeve can be placed between the die and the stamp via a loading opening that is sufficiently large such that the conduit and the sleeve can fit through the loading opening. In particular with a curved receiving surface of the die, providing a sufficiently large loading opening might only be possible if the distance between the die and the stamp is significantly larger than the diameter of the sleeve before the compressing.

In the present embodiment the distance between the die and the stamp can be particularly small due to the fact that the die can be brought into a loading position, wherein the conduit with the sleeve can be loaded into the device. That is, by pivoting the die into the loading position a particularly large loading opening can be obtained.

In the present embodiment the die is preferably configured in a pivotable manner such as to be pivotable between a loading state for positioning the conduit with the sleeve between the stamp and the die and an operation state for compressing and severing the sleeve. In the operation state the die is preferably arranged such as would be the case with a die that is fixedly attached to the device, that is a die that is configured in a non-pivotable manner. In the operation state the die is arranged such that the compressing and severing according to the described method can be performed. In the loading state the device can be loaded with the sleeve that surrounds the conduit. That is, the loading state is supposed to be used for the positioning of the conduit with the sleeve between the die and the stamp.

It is preferred that the die can be locked in the operation state and/or in the loading state. In particular, locking the die in the operation state has the advantage that during operation, that is doing compressing and severing of the sleeve, the die cannot move. That is, the die can be used efficiently as a counterpart for the stamp.

It is preferred that the die is configured such that a retaining force acts on the die such as to pivot the die into the operation state. This can be achieved, for example, by means of a spring that is attached between the die and a further element of the device. Due to the retaining force the die is generally kept in the operation state, from where it can be pivoted for loading the device. After loading, without any further action required, the die is pivoted back into the operation state due to the retaining force.

Further benefits and details of the method and the device will be explained with the aid of the exemplary embodiments presented in the drawings, without the subject matter of the invention being limited to these exemplary embodiments.

<FIG> show schematic illustrations of a severing according to the method of the present invention. Starting with <FIG>, a severing tool <NUM> is lowered onto a sleeve <NUM>. At first, the severing tool <NUM> is brought into contact with the outermost portions of the sleeve <NUM> such that two short sections of a contact line <NUM> are formed (<FIG>. Therein, a central portion <NUM> of the sleeve is not yet in contact with the severing tool <NUM>. With the severing tool <NUM> being lowered further, the sections of the contact line <NUM> become longer such that a length LC of the contact line <NUM> can be seen (<FIG>). The length LC is the sum of the lengths of the two sections of the contact line <NUM>. Subsequently, also the central portion <NUM> of the sleeve contacts the severing tool <NUM> (<FIG>). Therein, the two sections of the contact line <NUM> merge. Finally, the entire sleeve is severed (<FIG>) and the severing tool <NUM> can be removed (<FIG>). By means of the described severing a severing edge <NUM> is obtained. The length LSE thereof is longer than the length LC of the contact line <NUM>. This condition is fulfilled at all times during severing. As indicated in <FIG>, the length LSE of the severing edge <NUM> is measured along a curved line on the upper surface of the sleeve <NUM>.

<FIG> show views of a conduit <NUM> with a compressed sleeve <NUM>. The severing shown in <FIG> can be performed with the shown conduit <NUM> and sleeve <NUM> in a compressed region <NUM>, by means of which a closure <NUM> is formed.

<FIG> show views of a device <NUM> for forming a fluid-tight separating closure of a conduit <NUM> with a sleeve <NUM> surrounding the conduit <NUM>. The device <NUM> can be used with the conduit <NUM> and the sleeve <NUM> shown in <FIG>. Thereby, the closure <NUM> shown in <FIG> can be obtained. Further, the severing depicted in <FIG> can be performed using the device <NUM> of <FIG>.

With the device <NUM> a method can be performed for the forming of the fluid-tight separating closure of the conduit <NUM> involving the following steps:.

<FIG> is a perspective view of the device <NUM> with a sleeve inserted into the die <NUM> prior to compressing. For clarity, the conduit <NUM> is not shown. <FIG> are corresponding side views.

<FIG> is a further perspective view of the device <NUM> prior to compressing. <FIG> is a perspective view after compressing. It can be seen that between the situations shown in <FIG> the sleeve <NUM> has been compressed by the stamp <NUM> and the die <NUM>.

In the shown device <NUM> the severing tool <NUM> is a knife, but could also be a punching stamp. From <FIG> it can be seen that the severing tool <NUM> is arranged within the stamp <NUM> such that the severing tool <NUM> and the stamp <NUM> jointly form a compression surface <NUM> for compressing the sleeve <NUM>, wherein the severing tool <NUM> can be moved so as to protrude from the compression surface <NUM> for severing the closure <NUM>. Also from <FIG> it can be seen that the die <NUM> has a curved receiving surface <NUM> for receiving the sleeve <NUM>. The severing tool <NUM> has a blade <NUM>, wherein the shapes of the receiving surface <NUM> and the blade <NUM> deviate from each other. The blade is shown in <FIG> and <FIG> to 11f.

As can be seen from <FIG>, <FIG>, the device <NUM> further comprises a stop <NUM> for limiting the movement of the die <NUM> and the stamp <NUM> relative to each other.

The device further comprises a first hydraulic cylinder <NUM> for moving the stamp <NUM> and a second hydraulic cylinder <NUM> for moving the severing tool <NUM>.

<FIG> show views of the stamp <NUM> and the severing tool <NUM> of the device <NUM> of <FIG>. The severing tool <NUM> has a blade <NUM>.

<FIG> is a perspective view, wherein the blade is received within the stamp <NUM> such that the blade <NUM> of the severing tool <NUM> and the stamp <NUM> jointly form a compression surface <NUM> for compressing the sleeve <NUM>. This situation is also shown in <FIG> as a side view of the stamp <NUM>, the blade <NUM> of the severing tool <NUM> and the sleeve <NUM>. The sleeve <NUM> is shown in a compressed state. The blade <NUM> of the severing tool <NUM> can be moved out of the stamp <NUM> so as to protrude from the compression surface <NUM> for severing the sleeve <NUM>. This is shown in <FIG>.

<FIG> show six views of different blades <NUM> for the device <NUM> of <FIG>. In <FIG> the blade <NUM> has the shape of a straight line. In <FIG> the blade <NUM> has the shape of a curved line with a protruding central region. In <FIG> the blade <NUM> has the shape of a curved line with multiple recesses.

<FIG> and <FIG> show two embodiments of a device <NUM> for forming a fluid-tight separating closure of a conduit <NUM> with a sleeve <NUM> surrounding the conduit <NUM>. Unless specified otherwise, the devices <NUM> shown in <FIG> and <FIG> have the same features that have been described before. In the devices <NUM> shown in <FIG> and <FIG> the die <NUM> is configured in a pivotable manner. Therefore, a pivot point <NUM> is indicated in the figures. The die <NUM> can be pivoted around the pivot point <NUM>. Thereby, the die <NUM> can be pivoted between a loading position (indicated by the die <NUM> in dashed lines) and an operation state (indicated by the die <NUM> in solid lines). Although in <FIG> and <FIG> the die <NUM> is shown twice (once in dashed lines and once in solid lines), the devices <NUM> actually comprise only one die <NUM>, which is shown in two different states.

The conduit <NUM> with the sleeve <NUM> can be moved towards the die <NUM> as indicated by the upper conduit <NUM> and sleeve <NUM> in dashed lines in <FIG>. Then, the die <NUM> can be pivoted into the loading state, which is indicated by the die <NUM> in dashed lines. This can be done, for example, by pushing the conduit <NUM> with the sleeve <NUM> against the die <NUM>. If the die <NUM> is in loading state the conduit <NUM> and the sleeve <NUM> can be moved through a loading opening <NUM>. This is indicated in <FIG> by the lower conduit <NUM> and sleeve <NUM> in dashed lines. Afterwards, the die <NUM> can be brought into the operation state, which is indicated by the die <NUM> in solid lines. In this state the compressing and severing can be performed. This is indicated in <FIG> by means of the conduit <NUM> and sleeve <NUM> in solid lines in a non-deformed state before compressing and severing and in a deformed state after compressing and severing.

In <FIG> a device <NUM> is shown that are similar to the device <NUM> of <FIG>. Only the differences are explained. The device <NUM> comprises a spring <NUM>, by means of which the die <NUM> can be moved into the operation state. The spring <NUM> is shown in <FIG> twice, once for the operation state (wherein the spring <NUM> is not extended) and once for the loading state (wherein the spring <NUM> is extended). The device <NUM> actually comprises only one spring <NUM>. Further, a lock <NUM> is shown, by means of which the die <NUM> can be locked in the operation state.

<FIG> shows an operating head <NUM> of an electrohydraulic apparatus which is suitable, and intended, in particular for single-handed operation. The operating head <NUM> has a cylinder <NUM>, which is connected to the operating head in a fixed position. A piston <NUM> can be moved within the cylinder <NUM>. The cylinder <NUM> has an opening <NUM>, which is delimited by a collar <NUM>. The piston <NUM> extends through the opening <NUM>. On its end portion, which projects into the cylinder <NUM>, the piston <NUM> has a seal <NUM>, by means of which the piston <NUM> is sealed in relation to the cylinder <NUM>. The seal <NUM> is a radial shaft seal, which is supported on an encircling flange <NUM>.

In the position illustrated in <FIG> the flange <NUM> butts against the collar <NUM>, and this therefore delimits the travel path of the piston <NUM>.

The free end region of the piston <NUM>, that is to say the region which is located opposite the region located in the cylinder <NUM>, is connected to a stamp <NUM> directly or indirectly. The stamp <NUM> is connected to the end region <NUM> preferably in a releasable manner.

The operating head <NUM> has guide means (not illustrated specifically) for the purpose of guiding the stamp <NUM>. The guide means can be, for example, a tongue/groove guide. It is also possible for the operating head <NUM> to have an accommodating space <NUM>, into which the stamp <NUM> can be introduced at least to some extent. However, in the operating state of the operating head <NUM>, the stamp <NUM> cannot be moved out of the accommodating space <NUM>. Preferably the maximum displacement path of the piston <NUM> is dimensioned correspondingly for this purpose. The distance between the rear side of the stamp <NUM> and the side surface <NUM> of the accommodating space <NUM>, said surface running essentially parallel to the rear side <NUM>, is greater than the maximum possible displacement path of the piston <NUM>.

The piston <NUM> is designed in the form of a hollow cylinder. The piston <NUM> contains a piston <NUM>, which can be moved in an axial direction of the piston <NUM>. The piston <NUM> has seals <NUM>, which serve for sealing purposes. Thus, a hydraulic fluid cannot flow through the hollow-cylindrical piston <NUM>.

A rod <NUM> is connected to the piston <NUM>. That end portion of the rod <NUM> which is located opposite the piston <NUM> is connected to a cutting tool <NUM>. The cutting tool <NUM> can be displaced in the axial direction within the stamp <NUM>. For this purpose, the stamp <NUM> has a corresponding gap <NUM>. The rod <NUM> and the inner end region <NUM> of the piston <NUM> are designed such that the rod <NUM> is guided in the piston <NUM>.

The piston <NUM> contains a shoulder <NUM>, on which a bushing <NUM> is supported. A compression spring <NUM> is provided between the piston <NUM> and the periphery of the bushing <NUM> which is oriented towards the rod <NUM>.

It can be seen from <FIG> that the stamp <NUM> is connected to a tension spring <NUM>. The opposite end of the tension spring <NUM> is connected to the operating head <NUM> in a fixed position.

The stamp <NUM> and the cutting tool <NUM> form a moveable jaw. A two-part die <NUM> is arranged opposite the stamp <NUM>. A spacer <NUM> is provided between the two parts of the die <NUM> and therefore the gap produced in the die <NUM> is sufficient for the cutting tool <NUM> to be able to project at least to some extent into said gap.

A pressure is generated within the cylinder <NUM> by means of an electrically operated hydraulic unit (not illustrated). The pressure in the cylinder <NUM> is sufficient to displace the piston <NUM> out of its starting position into the end position, which is illustrated in <FIG>. The collar <NUM> here forms a stop for the flange <NUM>. Until this end position is reached, the apparatus is designed preferably such that no movement or displacement of the piston <NUM> takes place. If a conduit with a sleeve (not illustrated) is located between the die <NUM> and the stamp <NUM>, they are compressed with one another in a fluid-tight manner. When the piston <NUM> reaches its end position, as is illustrated in <FIG>, then the pressure prevailing in the cylinder <NUM> acts on the piston <NUM>. The piston <NUM> is displaced counter to the force of the compression spring <NUM>, as a result of which the cutting tool <NUM>, which is connected to the piston <NUM> by means of the rod <NUM>, is introduced between the parts of the die <NUM> and therefore the fluid-tight closure (not illustrated) is severed.

The movement of the stamp <NUM> tensions the tension spring <NUM>. The movement of the piston <NUM> compresses the compression spring <NUM>. Once operation as such has been completed, the pressure in the cylinder <NUM> is reduced. The pressure is reduced to the extent where both the tension spring <NUM> and the compression spring <NUM> are relieved of stressing. This causes the piston <NUM> to be displaced into its starting position. In addition, the piston <NUM> is returned into its starting position as a result of the tension spring <NUM> being relieved of stressing. The movement of the piston <NUM> by the compression spring <NUM> also results in the cutting tool <NUM>, which is connected to the piston <NUM> via the rod <NUM>, being retracted into the stamp <NUM>, and it is therefore preferably the case that the cutting tool <NUM>, in its starting position, does not project out of the punch.

An electrohydraulically operating tool comprising the operating head illustrated in <FIG> is also suitable for compressing, and severing, a conduit with a sleeve of different diameters, this resulting in a fluid-tight separation closure of the conduit. It is possible here to use conduits of different diameters with sleeves of different diameters. The collar <NUM> and the flange <NUM> delimit the displacement path of the piston <NUM>. This delimitation of the piston <NUM> and corresponding dimension of the stamp <NUM> can define a fluid-tight separation closure of a conduit for a lower limit of the conduit and of the sleeve.

It is not imperative for the piston <NUM> to be displaced as far as its end position, which is illustrated in <FIG>, by a movement of the stamp <NUM> when the sleeve is being compressed. If a conduit with a relatively large sleeve is introduced between the stamp <NUM> and the die <NUM>, corresponding control or regulation of the pressure in the cylinder <NUM> can nevertheless achieve compression and severing. If, for example, a conduit has a greater external diameter, and a greater wall thickness, than the possible minimum, and if the sleeve associated with this relatively large conduit also has a correspondingly great diameter and great wall thickness, then the pressure generated in the cylinder <NUM> is high enough to compress the sleeve between the die <NUM> and the stamp <NUM>. In this case, the collar <NUM> does not come into abutment against the flange <NUM>. If the piston <NUM> has reached a position between the starting position and the collar <NUM>, which can be referred to as the end position for a certain conduit-and-sleeve configuration, then the piston <NUM> is subjected to the pressure acting in the cylinder <NUM>, and so the piston <NUM>, and therefore also the cutting tool <NUM>, causes the closure to be severed. Irrespective of the movement of the piston <NUM>, the pressure in the cylinder <NUM> is kept essentially constant.

The bushing <NUM> serves to avoid a collision between the cutting tool <NUM> and the spacer <NUM>, or generally to delimit the displacement path of the piston <NUM>.

The end periphery of the bushing <NUM> thus also serves as a stop for the piston <NUM>.

If an electrohydraulic apparatus is used with the described operating head <NUM> for the forming of a fluid-tight separating closure of a conduit, the piston <NUM> with the stamp <NUM> and the die <NUM> can be considered parts of a closure unit. Within the closure unit, the die <NUM> and the stamp <NUM> can be moved relatively to each other. If a conduit with a sleeve is provided and positioned within the closure unit between the die <NUM> and the stamp <NUM>, the sleeve can be compressed by such a relative movement between the die <NUM> and the stamp <NUM> in order to form a closure. The piston <NUM> with the cutting tool <NUM> can be considered part of a separating unit. By a relative movement between the closure unit and the separating unit the closure can be severed in a compressed region.

The closure can be severed in a compressed region by the cutting tool <NUM> such that a contact line between the cutting tool <NUM> and the sleeve during severing is shorter than an obtained severing edge of the sleeve. This cannot be seen from <FIG> since the cutting tool <NUM> conceals parts of the stamp <NUM>. Nevertheless, the above description of the method for the forming of a fluid-tight separating closure of a conduit applies to the described operating head <NUM> as well.

The closure unit comprising the piston <NUM> with the stamp <NUM> and the die <NUM> and the separating unit comprising the piston <NUM> with the cutting tool <NUM> can be considered parts of a device for forming a fluid-tight separating closure of a conduit with a sleeve surrounding the conduit.

Claim 1:
Method for the forming of a fluid-tight separating closure of a conduit (<NUM>) involving the following steps:
- providing of a conduit (<NUM>) with a sleeve (<NUM>),
- positioning of the conduit (<NUM>) with the sleeve (<NUM>) between a die (<NUM>) and a stamp (<NUM>),
- compressing of the sleeve (<NUM>) by a relative movement between the die (<NUM>) and the stamp (<NUM>) in order to form a closure (<NUM>);
- severing of the closure (<NUM>) in a compressed region (<NUM>) by a severing tool (<NUM>), the method being characterised in that the severing is carried out such that a contact line (<NUM>) between the severing tool (<NUM>) and the sleeve (<NUM>) during severing is shorter than an obtained severing edge (<NUM>) of the sleeve (<NUM>).