Patent Description:
Chromatography is a well-known procedure for analyzing and preparing chemical mixtures or chemical samples. The sample may typically be dissolved in a fluid, referred to as a buffer composition. The various sample components of the mixture may travel through a column at different speeds, causing them to separate. This separation may be used to separate the sample components in a fractionation step where the mobile phase may be directed to different containers, e.g. by an outlet valve of the chromatography apparatus.

The fractionation step may be controlled based on a sensor detecting various properties of the fluid exiting the column, e.g. detected ultraviolet light absorption properties of the fluid.

One problem with such chromatography systems is that air present in the fluid travelling through the column will interfere with the separation and detection of the properties of the fluid.

Some existing chromatography systems may address this by including an air trapping device e.g. having a sealed and elongated receptacle provided with an inlet and outlet arranged at the bottom part of the receptacle, the bottom being defined as an end portion oriented in the direction of gravity.

At least one problem with such conventional air trapping device is that portions of the fluid entering the air trapping device through the inlet will immediately exit the air trapping device through the outlet. Similarly, together with the portions of the fluid air trapped therein may also immediately exit the air trapping device through the outlet.

A further problem arises when the fluid provided to the chromatography apparatus changes as a gradient over time, e.g. from a fluid having low density to a fluid having a high density. Ideally the gradient should typically display a linear or desired characteristic. When portions of the fluid entering the air trapping device through the inlet immediately exit the air trapping device through the outlet, the linearity of the gradient will be degraded.

At least one problem with such conventional air trapping devices is the generation of foam within the air trapping device.

Various conventional devices are described, for example, in <CIT>, <CIT> and <CIT>.

Thus, there is a need for an improved air trapping device and nozzle therefor.

An objective of embodiments of the present invention is to provide a solution which mitigates or solves the drawbacks and problems described above.

The above and further objectives are achieved by the subject matter described herein. Further advantageous implementation forms of the invention are further defined herein.

More specifically, various aspects and embodiments of the present invention are defined by the appended claims.

Further applications and advantages of embodiments of the invention will be apparent from the following detailed description.

A more complete understanding of embodiments of the invention will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments.

An "or" in this description and the corresponding claims is to be understood as a mathematical OR which covers "and" and "or", and is not to be understand as an XOR (exclusive OR). The indefinite article "a" in this disclosure and claims is not limited to "one" and can also be understood as "one or more", i.e., plural.

In the present disclosure reference will be made interchangeably to receptacle, container or reservoir, signifying an arrangement suitable for holding fluid.

In the present disclosure reference will be made interchangeably to fluid inlet and inlet. In the present disclosure reference will be made interchangeably to fluid outlet and outlet.

<FIG> shows a nozzle <NUM> (not according to the invention) for an air trapping device configured to remove air from a fluid. The nozzle <NUM> is typically configured to be coupled to an inlet <NUM> of the air trapping device, e.g. by enclosing or being enclosed by the inlet <NUM>. The nozzle may further be provided with a seal arranged between the inlet and the nozzle, as further described in relation to <FIG>.

The nozzle <NUM> may comprise a body having an input opening <NUM> configured to receive the fluid and an output opening <NUM> configured to distribute the fluid along a trailing edge of the output opening <NUM>. In one example, the nozzle <NUM> is coupled to the inlet <NUM> of the air trapping device <NUM> and receives fluid from the inlet <NUM>. The fluid is then directed within a fluid channel within the body to the output opening <NUM>. The nozzle is typically configured to be oriented with the body having input opening <NUM> in the direction of gravity and the output opening <NUM> in a direction opposite to the direction of gravity. the body is configured to be vertically aligned with the direction of gravity. This has the effect that received fluid is distributed evenly along the edge of the output opening <NUM>. In one example, the body is shaped as a tubular or cylindrical element.

When fluid is distributed along the edge, one or more droplets will be formed that will grow in size until the force of gravity overcomes the surface tension. This may result in a pulsating flow of fluid over the edge.

To overcome this problem, the present disclosure provides an edge that comprises a control element <NUM> configured to reduce surface tension of the fluid. This feature has the effect to create an even flow of fluid along the edge by reducing the surface tension.

At least one advantage of the present disclosure is that the generation of foam is mitigated or reduced by ensuring gentle introduction of the fluid, received from the inlet <NUM>, into the receptacle <NUM>. Yet an advantage of the present disclosure is that foaming is further reduced by mitigating or reducing pulsation or variation in the fluid flow by introducing a control element <NUM>. This is achieved by introducing an edge comprising the control element <NUM> that will break up the surface tension and thereby mitigate or reduce the formation of droplets causing pulsation or variation of the fluid flow. The reduced pulsation or variation of the fluid flow further mitigates or reduces the formation or foam or foaming.

At high rates of fluid flow, a cylindrically formed nozzle may not be able to sustain the desired even flow of fluid along the edge and may even eject fluid in an upward direction opposite to the direction of gravity.

<FIG> shows a nozzle <NUM> for an air trapping device <NUM> having a body with a funnel shape according to one or more embodiments of the present disclosure. A nozzle <NUM> is provided wherein the body has a funnel shape and an input opening <NUM> being smaller than the output opening <NUM>. This has at least the effect of increasing the circumference of the edge and reducing the rate of fluid flow, thus creating an even flow of fluid along the edge also at high or higher rates of fluid flow than a nominal flow rate.

At least one advantage of the present disclosure is that the foaming or generation of foam is further mitigated or reduced by ensuring gentle introduction of the fluid, received from the inlet <NUM>, into the receptacle <NUM>. Yet an advantage of the present disclosure is that the flow of the fluid is kept more constant by providing a funnel shaped nozzle <NUM> ensuring a more constant flow of the fluid.

<FIG> shows an edge comprising a control element <NUM> having a sine shape according to embodiments of the present disclosure.

At least one advantage of the present disclosure is that the foaming may further be reduced by introducing a control element <NUM> having a sine shape, as shown in <FIG>.

<FIG> shows an edge comprising a control element <NUM> having a square shape according to embodiments of the present disclosure.

At least one advantage of the present disclosure is that the foaming may further be reduced by introducing a control element <NUM> having a square shape, as shown in <FIG>.

<FIG> shows an edge <NUM> having an edge with a plurality of slits according to embodiments of the present disclosure.

At least one advantage of the present disclosure is that the foaming may further be reduced by introducing a control element <NUM> with a plurality of slits, as shown in <FIG>.

<FIG> shows an edge comprising a control element <NUM> having a plurality of holes, according to embodiments of the present disclosure.

At least one advantage of the present disclosure is that the foaming may further be reduced by introducing a control element <NUM> having a plurality of holes, as shown in <FIG>.

In situations when the edge of the output opening <NUM> is located above a current fluid level in the receptacle <NUM> of the air trapping device <NUM>, foam may be generated or air may be introduced into the fluid, e.g. when fluid leaving the edge comprising a control element <NUM> of the nozzle <NUM> hit the surface of the fluid in the receptacle <NUM>. In particular, when the fluid comprises protein molecules in the fluid, e.g. when the fluid is beer. At least one advantage of the present disclosure is that the generation of foam is mitigated or reduced by ensuring gentle introduction of the fluid, received from the inlet <NUM>, into the receptacle <NUM>. Yet an advantage of the present disclosure is that the flow of the fluid is kept more constant by providing a funnel shaped nozzle <NUM> ensuring a more constant flow of the fluid. Yet an advantage of the present disclosure is that foaming is further reduced by mitigating or reducing pulsation or variation in the fluid flow by introducing a control element <NUM>. This is achieved by introducing an edge comprising the control element <NUM> that will break up the surface tension and thereby mitigate the formation of droplets causing pulsation in the fluid flow. The foaming may further be reduced by introducing a control element <NUM> having a sine shape, as shown in <FIG>. Yet an advantage of the present disclosure is that foaming is further reduced by forcing the foam towards the current surface of the fluid in the receptacle <NUM>. This is achieved by locating the nozzle <NUM> top part, e.g. in an upper half or top quarter, of the tubular section.

These advantages are achieved by the air trapping device <NUM> and nozzle <NUM> according to one or more embodiments of the present disclosure.

The nozzle <NUM> further comprises a guiding element <NUM> coupled to the body of the nozzle <NUM> and configured to guide the fluid distributed along the edge of the output opening in a direction of gravity. The guiding element <NUM> gently guides the fluid distributed along the edge <NUM> of the output opening <NUM> in a direction of gravity, thus avoiding foaming or injection of air into the fluid.

At least one further advantage of the present disclosure is that the generation of foam is further mitigated or reduced by ensuring gentle introduction of the fluid, received from the inlet <NUM>, into the receptacle <NUM> by introducing a guiding element <NUM>.

<FIG> shows a nozzle for an air trapping device having a guiding element according to one or more embodiments of the present disclosure. The guiding element <NUM> may be coupled to the body of the nozzle <NUM> by enclosing an exterior wall <NUM> of the body of the nozzle <NUM> somewhere between the input opening <NUM> and the output opening <NUM>. In other words, coupled somewhere along the exterior wall <NUM> of the body of the nozzle <NUM> below the edge <NUM> in the direction of gravity.

In one example the nozzle <NUM> is funnel shaped and having an exterior wall <NUM> which is connecting the input opening <NUM> and the output opening <NUM>. The guiding element <NUM> may then be shaped as a tube and oriented with its longitudinal axis in the direction of gravity, whereby one open end of the tube enclose the exterior wall of the body of the nozzle somewhere between the input opening <NUM> and the output opening <NUM>. The guiding element <NUM> may be coupled to the nozzle <NUM> e.g. by molding the nozzle <NUM> and guiding element <NUM> as one unit, by welding the nozzle <NUM> and guiding element <NUM> together or by gluing the nozzle <NUM> and guiding element <NUM> together.

In one embodiment of the present disclosure, the guiding element <NUM> has a dual functionality. The first functionality is, as described above, to guide the fluid distributed along the edge of the output opening in a direction of gravity and the second functionality is to provide fluid to the nozzle from the fluid inlet of the receptacle <NUM> of the air trapping device <NUM>. In other words, fluid is guided to the control element <NUM> within an interior wall of the nozzle and fluid is from the edge by the exterior wall <NUM>.

In one or more embodiments of the present disclosure, the guiding element <NUM> comprises a tubular element coupled in a fluid tight manner to the input opening <NUM> of the body of the nozzle <NUM> and is further couplable to a fluid inlet <NUM> of the air trapping device <NUM>. The guiding element <NUM> may be coupled to the body of the nozzle <NUM> e.g. by molding the nozzle <NUM> and guiding element <NUM> as one unit, by welding the nozzle <NUM> and guiding element <NUM> together or by gluing the nozzle <NUM> and guiding element <NUM> together. The guiding element <NUM> may be configured to be oriented with its longitudinal axis in the direction of gravity or aligned and centered with a longitudinal axis of the nozzle <NUM>.

In some situations, it may be beneficiary to provide fluid to the nozzle <NUM> from a direction other than from the direction of gravity. An embodiment achieving this is further described below.

<FIG> shows a nozzle <NUM> for an air trapping device <NUM> having a guiding element <NUM> and a feeder element <NUM> according to one or more embodiments of the present disclosure. The nozzle <NUM> further comprises a feeder element <NUM>. The feeder element <NUM> is configured to provide fluid to the nozzle <NUM> from the fluid inlet <NUM> of the receptacle <NUM> of the air trapping device <NUM>. The feeder element <NUM> comprises a tubular element coupled to the input opening <NUM> of the body and is further couplable to a fluid inlet <NUM> of the air trapping device <NUM>.

<FIG> shows an air trapping device <NUM> according to one or more embodiments of the present disclosure. <FIG> shows a drawing the air trapping device <NUM> and <FIG> shows a section drawing of the air trapping device <NUM>.

The air trapping device <NUM> is configured to remove air from the fluid. The device comprises: a receptacle <NUM> configured to hold the fluid, a nozzle <NUM> according to any of the embodiments described herein comprised in the receptacle <NUM>.

The receptacle <NUM> comprises a lid section <NUM>, a drainage section <NUM> comprising an outlet <NUM> and an inlet <NUM>. The outlet <NUM> is configured to provide fluid from the receptacle <NUM> to
an external receiving unit, e.g. a chromatography apparatus. The inlet <NUM> is configured to provide fluid to the receptacle <NUM>, e.g. from an external source such as a fluid reservoir.

The air trapping device <NUM> further comprises a tubular section <NUM> interconnecting the lid section <NUM> with the drainage section <NUM>, i.e. to form a sealed and fluid tight receptacle <NUM>. In one example, this may be a tube made of glass or any other suitable material.

An important principle of the present disclosure is that fluid entering the receptacle <NUM> via the inlet <NUM> will require substantially the same time to pass through the air trapping device <NUM> to the outlet <NUM> regardless of the density of the fluid assuming a constant fluid flow rate through the inlet <NUM>. This ensures a close match to a desired fluid gradient, e.g. a linear behavior when the fluid changes as a gradient over time from a fluid having low density to a fluid having a high density. This is achieved by the air trapping device <NUM> by providing fluid at the top of the receptacle <NUM> via the nozzle <NUM> and extracting fluid at the bottom of the receptacle <NUM> at the drainage section <NUM>.

Another important principle is to allow air still imbedded in the fluid, after leaving the control element <NUM>, time to reverse its direction of travel from the top to the bottom, due to buoyancy of the air in the fluid, and return to the surface of the fluid, thus further reducing the amount of air in the fluid. This is achieved by providing a tubular section <NUM> which have a relatively large cross section in relation to a cross section of the nozzle <NUM>. This will ensure a relatively low fluid flow rate from the edge <NUM> to the outlet <NUM> in relation to the fluid flow rate from the inlet <NUM> to the edge <NUM>, thus further reducing the amount of air in the fluid.

In one or more embodiments, the nozzle <NUM> comprises a guiding element <NUM> having a cross section which have an area less than or equal to <NUM>/<NUM> of an area of a cross section of the tubular section <NUM>. In one or more embodiments, the nozzle <NUM> comprises a guiding element <NUM> having a cross section which have an area less than or equal to <NUM>/<NUM> of an area of a cross section of the tubular section <NUM>.

At least one advantage of the present disclosure is that further air is removed from the fluid by increasing the time for air, imbedded or trapped in the fluid, to reverse its direction of travel from the top to the bottom, due to buoyancy of the air in the fluid, and return to the surface of the fluid. This is ensured by allowing a low rate of fluid flow in the receptacle <NUM> compared to the rate of fluid flow in the inlet <NUM>. In other words, the larger the cross section of the tubular section <NUM> is in relation to the cross section of the guiding element <NUM>, the lower the rate of fluid direction of travel from the top to the bottom will be. The low rate of fluid flow is achieved by a guiding element <NUM> having a cross section which have an area less than or equal to <NUM>/<NUM> or <NUM>/<NUM> of an area of a cross section of the tubular section <NUM>.

In one example, the guiding element <NUM> has a diameter of <NUM> and the tubular section <NUM> has a diameter of <NUM>. The guiding element <NUM> then has a cross section with an area of <NUM> ^<NUM> * π = <NUM> and the cross section of the tubular section <NUM> then has an area of equal to <NUM>,<NUM> ^<NUM> * π ≈ <NUM>. The guiding element <NUM> then has a cross section with an area ≈ <NUM>/<NUM> of the cross section of the tubular section <NUM>.

In some situations, when the fluid travels from the control element <NUM> to the outlet <NUM>, some areas of the drainage section <NUM> will form dead zones or stagnant zones where fluid remain stationary. This problem is addressed by the embodiments in <FIG> and <FIG> further described below.

<FIG> shows an air trapping device having a drainage section that comprises a plurality of openings according to one or more embodiments of the present disclosure. The drainage section <NUM> of the air trapping device <NUM> comprises a plurality of openings <NUM>-<NUM> facing the tubular section. Each opening is then coupled or connected to the fluid outlet <NUM>, e.g. by fluid channel elements. The plurality of openings may comprise <NUM>-<NUM> openings or any other suitable number of openings. This embodiment reduces the formation of dead zones or stagnant zones by extracting fluid in multiple locations.

<FIG> shows an air trapping device <NUM> having a drainage section having a funnel shape according to one or more embodiments of the present disclosure. The drainage section <NUM> of the air trapping device <NUM> is configured as having a funnel shape and having an opening facing the tubular section and being coupled to the fluid outlet <NUM>. The opening facing the tubular section may have a cross section equal to the cross section of the tubular section <NUM>.

As mentioned above, it is desirable to have a relatively low fluid flow rate from the edge <NUM> to the outlet <NUM> in relation to the fluid flow rate from the inlet <NUM> to the edge <NUM>. This is achieved by the embodiment below by further increasing the cross section of the tubular section <NUM> by an annular bulge <NUM>.

<FIG> shows an air trapping device having a tubular section <NUM> with an annular bulge <NUM> according to one or more embodiments of the present disclosure. The tubular section <NUM> may further comprise an annular bulge <NUM>. This will ensure a relatively low fluid flow rate from the control element <NUM> to the outlet <NUM> in relation to the fluid flow rate from the inlet <NUM> to the edge <NUM>, thus further reducing the amount of air in the fluid.

As the fluid generally has a higher density than air, the fluid will seek to flow downwards in the direction of gravity. On the other hand air trapped in the fluid and having a lower density than the fluid, will seek to flow or travel in a direction opposite to the direction of gravity. The air trapping device <NUM> is therefore adapted to be used with its longitudinal axis aligned with the direction of gravity such that the drainage section <NUM> is oriented in the direction of gravity and the lid section <NUM> is oriented in a direction opposite to the direction of gravity.

In one or more embodiments, the device is configured to be operated when oriented with the lid section <NUM> in a direction opposite to the direction of gravity. In one or more embodiments, the device is configured to be operated when oriented with the lid section <NUM> in a direction opposite to the direction of gravity and the drainage section <NUM> is oriented in the direction of gravity.

As described further above, air trapping device <NUM> is configured to allow fluid to flow from the control element <NUM> of the nozzle <NUM> to the outlet <NUM>. It is desirable that the control element <NUM> is located above the surface of the fluid in the receptacle <NUM> to allow air still imbedded in the fluid, after leaving the control element <NUM>, time to reverse its direction of travel from the top to the bottom, due to buoyancy of the air in the fluid, and return to the surface of the fluid.

In one or more embodiments, the air trapping device <NUM> is provided with the output opening <NUM>, or the control element <NUM>, of the nozzle located in an upper or top section of the tubular section <NUM>. In one or more embodiments, the air trapping device <NUM> is provided with the output opening <NUM>, or the control element <NUM>, of the nozzle located in an upper half of the tubular section <NUM>. In one or more embodiments, the air trapping device <NUM> is provided with the output opening <NUM>, or the control element <NUM>, of the nozzle located in a top quarter of the tubular section <NUM>. In one or more embodiments, the air trapping device <NUM> is provided with the output opening <NUM>, or the control element <NUM>, of the nozzle <NUM> located in an upper <NUM>/<NUM> section of the tubular section <NUM>, i.e. the output opening <NUM>, or the control element <NUM>, of the nozzle is located in the upper <NUM>% of the total height of the tubular section <NUM>.

At least one advantage of this embodiment is that foaming is further reduced by forcing the foam towards the current surface of the fluid in the receptacle <NUM>. This is achieved by locating the nozzle <NUM> top part, e.g. in an upper half or top quarter, of the tubular section. Yet an advantage is that the time for air imbedded or trapped in the fluid to reverse its direction of travel from the top to the bottom is increased, due to buoyancy of the air in the fluid, and return to the surface of the fluid.

<FIG> shows an exploded view of an example of the air trapping device <NUM> according to one or more embodiments of the present disclosure. The exploded view shows the same features as the feature shown in <FIG>, <FIG> and <FIG>:
I. a nozzle <NUM>, a lid section <NUM>, a drainage section <NUM> and a tubular section <NUM>, e.g. a glass tube.

In addition, the air trapping device <NUM> comprises:
a connector <NUM>, an air valve plunge <NUM>, O-rings <NUM>-<NUM>, a locking screw <NUM> and an O-ring <NUM>, configured to seal the coupling between the tubular section <NUM> and the drainage section <NUM>. The air trapping device <NUM> further comprises a distance screw <NUM>, configured to couple the lid <NUM>. The air trapping device <NUM> further comprises a drainage section <NUM>, a protective cover <NUM> configured to protect the tubular section <NUM>. The air trapping device <NUM> further comprises a plug <NUM> configured to fill a bore. The air trapping device <NUM> further comprises a mounting screw <NUM>, e.g. head Screw ISO <NUM> M5x35 A4-<NUM>. The air trapping device <NUM> further comprises labels <NUM>-<NUM> indicative of the inlet <NUM> and the outlet <NUM>.

<FIG> shows an example of the nozzle according to one or more embodiments of the present disclosure. An exemplary embodiment of the nozzle is shown in <FIG>. The funnel shape of the nozzle has an opening angle of <NUM> degrees, as can be seen in the section A-A of <FIG>. The control element may comprise <NUM> sections, each comprising at least one full a sine shape or period. Each section may correspond to <NUM> degrees of the control element <NUM>. As can be seen from <FIG>, the control element may comprise six "valley" sub-sections having a radius of <NUM> and <NUM> "ridge" sections having a radius of <NUM>.

Claim 1:
An air trapping device (<NUM>) configured to remove air from a fluid, the device comprising:
a receptacle (<NUM>) configured to hold the fluid,
a nozzle (<NUM>) comprised in the receptacle (<NUM>), the nozzle (<NUM>) comprising a body having an input opening (<NUM>) configured to receive the fluid and an output opening (<NUM>) configured to distribute the fluid along an edge of the output opening (<NUM>), wherein the edge comprises a control element (<NUM>) configured to reduce surface tension of the fluid,
wherein the receptacle (<NUM>) comprises,
a lid section (<NUM>),
a drainage section (<NUM>) comprising a fluid outlet (<NUM>) and a fluid inlet (<NUM>), and
a tubular section (<NUM>) interconnecting the lid section (<NUM>) with the drainage section (<NUM>), and
wherein the output opening (<NUM>) of the nozzle is located in a top quarter of the tubular section (<NUM>);
wherein the body of the nozzle (<NUM>) has a funnel shape and an input opening (<NUM>) being smaller than the output opening (<NUM>);
wherein the control element (<NUM>) is formed as one of a sine shape, a square shape, an edge with slits or an edge with a plurality of holes;
a guiding element (<NUM>) coupled to the body of the nozzle (<NUM>) and configured to guide the fluid distributed along the edge of the output opening (<NUM>) in a direction of gravity, wherein the guiding element (<NUM>) comprises a tubular element coupled to the input opening (<NUM>) of the body of the nozzle (<NUM>) and is further couplable to the fluid inlet of the air trapping device (<NUM>.