TECHNICAL FIELD

The invention relates to an exchangeable separation insert for a modular centrifugal separator. The invention further relates to a modular centrifugal separator.

BACKGROUND

In the field of pharmaceuticals, biopharmaceuticals, biotechnology and thereto related fields separation of substances from a liquid mixture, such as separation of cells from a cell culture, are performed in a sterile environment. Traditionally, equipment made e.g. from stainless steel has been used, which equipment is sterilised between batches.

Lately, disposable separation equipment made for single use, i.e. for one batch or a limited number of batches, has been suggested. For instance, US2011/0319248 discloses a single use centrifuge and WO 2015/181177 discloses a separator comprising an exchangeable inner drum.

WO 2015/181177 discloses a separator for the centrifugal processing of a flowable product comprising a rotatable outer drum and an exchangeable inner drum arranged in the outer drum. The inner drum comprises means for clarifying the flowable product. The outer drum is driven via a drive spindle by a motor arranged below the outer drum. The inner drum extends vertically upwardly through the outer drum with fluid connections arranged at an upper end of the separator.

SUMMARY

An exchangeable separation insert of a modular centrifugal separator requires secure positioning within a stationary frame and a rotatable member of the modular centrifugal separator.

It is an object of the invention to provide an exchangeable separation insert which is configured to be securely positioned within a modular centrifugal separator.

According to an aspect of the invention, at least one of the above mentioned objects is achieved by an exchangeable separation insert for a modular centrifugal separator. The exchangeable separation insert comprises a rotor casing rotatable about an axis of rotation and a first stationary portion. The rotor casing delimits a separation space and comprises frustoconical separation discs arranged in the separation space. A first fluid passage extends through the first stationary portion into the separation space. The axis of rotation extends along an axial direction and the rotor casing has a first axial end portion and a second axial end portion. The first stationary portion is arranged at the first axial end portion. The first stationary portion is biased in a first direction away from the rotor casing along the axial direction.

Since the first stationary portion is biased in a first direction away from the rotor casing along the axial direction, the exchangeable separation insert is configured for being compressed by positioning the first stationary portion towards the rotor casing in a second direction opposite to the first direction, i.e. against the bias. The bias of the first stationary portion in the first direction, will contribute to securely position the exchangeable separation insert within the modular centrifugal separator when mounted therein. Thus, the above object is achieved.

It is a further object of the invention to provide for a modular centrifugal separator comprising a securely positioned exchangeable separation insert.

According to a further aspect of the invention, at least one of the above mentioned objects is achieved by a modular centrifugal separator configured for separating a liquid feed mixture into a heavy phase and light phase. The modular centrifugal separator comprises an exchangeable separation insert according to any one of aspects and/or embodiments discussed herein and a base unit. The base unit comprises a stationary frame, a rotatable member, and a drive unit for rotating the rotatable member. The rotor casing of the exchangeable separation insert is releasably engaged inside the rotatable member, and the first stationary portion is releasably engaged with the stationary frame. The first stationary portion is arranged in a first proximal position along the axial direction, counter to the bias in the first direction. The first proximal position is closer to the rotor casing than a first distal end position of the first stationary portion provided in an unmounted state of the exchangeable separation insert.

Since, the exchangeable separation insert is configured for being compressed by positioning the first stationary portion, against the bias, towards the rotor casing in a second direction opposite to the first direction, and since the first stationary portion is arranged in a first proximal position along the axial direction, counter to the bias in the first direction, the bias of the first stationary portion in the first direction, will contribute to securely position the exchangeable separation insert within the stationary frame and the rotatable member in the base unit of the modular centrifugal. Thus, the above mentioned further object is achieved.

The modular centrifugal separator may comprise two main parts, the base unit and the exchangeable separation insert. The base unit may comprise basic components for supporting and rotating the exchangeable separation insert such as the above mentioned stationary frame and rotatable member. The exchangeable separation insert may be configured for the actual separation of the liquid feed mixture to take place in the separation space thereof. The liquid feed mixture may flow via one fluid connection into the separation space and the separated heavy and light phases may leave the separation space via one fluid connection each. The first fluid passage may form part of one of the fluid connections.

The exchangeable separation insert may be configured for single use, i.e. for separation of one batch only or a limited number of batches of liquid feed mixture. The base unit on the other hand may be configured for repeated use with different exchangeable separation inserts, i.e. the base unit may be used for the separation of numerous batches of liquid feed is mixture using different exchangeable separation inserts.

When the modular centrifugal separator is in an assembled state, the rotor casing of the exchangeable separation insert is engaged inside the rotatable member, and the first stationary portion is engaged with the stationary frame. As mentioned above, both the rotatable member and the first stationary portion are releasably engaged, and thus, the exchangeable separation insert may be exchanged for a new and used exchangeable separation insert after separation of a batch of liquid feed mixture. The first stationary portion is arranged in the first proximal position when the exchangeable separation insert is mounted in the base unit. Before and after being mounted in the base unit, due to the bias, the first stationary portion is arranged in the first distal end position. As mentioned above, the bias in the first direction contributes to securing the exchangeable separation insert in the base unit. Further means and/or measures for securing the exchangeable separation insert in the base unit may be provided, such as e.g. engaging means between the rotor casing and the rotatable member, engaging means between the first stationary portion and the stationary frame, etc.

Herein the term bias/biased is synonymous with the term pretension/pretensioned.

The exchangeable separation insert may be configured to form the only part of the modular centrifugal separator, which is in contact with the liquid feed mixture, and the separated heavy and light phases. Thus, the exchangeable separation insert may be provided to a user as a sterile entity. The sterile entity may include parts configured for separating the liquid feed mixture as well as conduits for the liquid feed mixture and the separated heavy and light phases. The exchangeable separation insert is mounted in the base unit by the user. Thus, the user will readily have available a centrifugal separator with a sterile environment for separation of the liquid feed mixture.

The rotatable member may be rotatably supported in the stationary frame. The rotatable member may be supported in the stationary frame without the aid of a spindle or other kind of rotor shaft. The stationary frame is stationary in the sense that it is stationary during use of the modular centrifugal separator while the rotatable member is configured to rotate together with the rotor casing during use of the modular centrifugal separator.

When the exchangeable separation insert is mounted in the base unit, the rotor casing may be received in an inner space of the rotatable member. Suitably, the rotatable member may be provided with an opening at a first axial end of the rotatable member for at least one fluid connection of the exchangeable separation insert to extend therethrough.

The exchangeable separation insert may further comprise a second stationary portion provided with a second fluid passage. Accordingly, the rotatable member may be provided with an opening at an opposite second axial end thereof. At least one fluid connection of the exchangeable separation insert may extend through the opening at the second axial end of the rotatable member.

According to embodiments, the first stationary portion may comprise a first set of springs, the first set of springs comprising at least one spring element. The at least one spring element of the first set of springs may be arranged in the first stationary portion such that when energy is stored in the at least one spring element of the first set of springs, the first stationary portion is biased in the first direction away from the rotor casing along the axial direction. In this manner, the bias of the first stationary portion in the first direction may be achieved.

Throughout this disclosure, a spring element may be e.g. a compression spring or an extension spring. As is commonly known, energy is stored in a spring element by displacing at least a portion of the spring element from its equilibrium position, i.e. e.g. by compressing a compression spring, and by extending an extension spring.

According to embodiments, the exchangeable separation insert may comprise a first sealing member, wherein the first sealing member seals the first fluid passage in a transition between the first stationary portion and the rotor casing. In this manner, a mechanical hermetical seal of the first fluid passage may be provided between the rotor casing and the first stationary portion. For instance, if the first fluid passage forms part of an inlet for the liquid feed mixture, the first sealing member may provide a mechanically hermetically sealed inlet of the modular centrifugal separator.

According to embodiments, the first sealing member may comprise a first stationary sealing element provided with a first stationary sealing surface arranged in the first stationary portion and a first rotatable sealing element provided with a first opposite sealing surface arranged in the rotor casing. The first stationary sealing surface may abut against the first opposite sealing surface. In this manner, a mechanical hermetical seal may be provided.

According to embodiments, the first stationary portion may be axially displaceable in relation to the first stationary sealing element. The at least one spring element of the first set of springs may be arranged between the first stationary portion and the first stationary sealing element such that when energy is stored in the at least one spring element of the first set of springs, the first stationary portion is biased in the first direction away from the rotor casing along the axial direction and the first stationary sealing element is pressed against the first rotatable sealing element. In this manner, sealing abutment between the first stationary sealing element and the first rotatable sealing element may be achieved. More specifically, in this manner sealing abutment between the first stationary sealing surface and the first opposite sealing surface may be ensured in order to provide a mechanical hermetical seal of the first fluid passage. At the same time the bias of the first stationary portion in the first direction away from the rotor casing may be achieved, which may contribute to positioning the exchangeable separation insert within the base unit of the modular centrifugal separator, as discussed above.

According to embodiments, the exchangeable separation insert may comprise a first stop mechanism for preventing the first stationary portion from being biased in the first direction away from the rotor casing along the axial direction beyond a first distal end position. In this manner, it may be ensured that exchangeable separation insert may be handled as one unit. The first stop mechanism may prevent the first stationary portion from being separated from the rotor casing, which might otherwise occur due to the bias of the first stationary portion in the first direction. Accordingly, also in the first distal position, the first stationary portion may be biased in the first direction away from the rotor casing.

According to embodiments, the exchangeable separation insert may comprise a second stationary portion, wherein a second fluid passage may extend through the second stationary portion into the separation space. The second stationary portion may be arranged at the second axial end portion of the rotor casing. The second stationary portion may be biased in a second direction away from the rotor casing along the axial direction. In this manner, a further fluid connection to or from the separation space may be provided at the second axial end portion of the rotor casing, opposite to the first axial end portion. Moreover, since the second stationary portion may be biased in the second direction, the exchangeable separation insert is configured for being compressed by positioning the second stationary portion towards the rotor casing in the first direction opposite to the second direction, i.e. against the bias in the second direction. The bias of the second stationary portion in the second direction, will contribute to securely position the exchangeable separation insert within the modular centrifugal separator when mounted therein.

According to embodiments, a third fluid passage may extend through the first stationary portion into the separation space, wherein the exchangeable separation insert comprising a third sealing member x, and wherein the third sealing member x at least partially seals the third fluid passage in a transition between the first stationary portion and the rotor casing. In this manner, at least part of the third fluid passage may be mechanically hermetically sealed between the rotor casing and the first stationary portion. For instance, if the third fluid passage forms part of an outlet from the separation space, the third sealing member may mechanically hermetically seal at least part of the outlet. According to some embodiments the first sealing member may mechanically hermetical seal a further part of the third fluid passage between the rotor casing and the first stationary portion.

Generally, a mechanical hermetical seal forms a completely different interface between rotating and stationary parts of the centrifugal separator than a hydraulic seal comprising e.g. a paring disc arranged inside a paring chamber, or a stationary disc submerged in a liquid inside the rotor casing. A mechanical hermetical seal includes an abutment between part of the rotatable rotor casing and a stationary portion. A hydraulic seal does not include an abutment between the rotating and stationary parts of a centrifugal separator.

Further features of, and advantages with, the invention will become apparent when studying the appended claims and the following detailed description.

