Field of the Invention

The present invention relates to a linear peristaltic pump for pumping fluid.

Background of the Invention

It is well known to use peristaltic pump for pumping a variety of fluids in large and heavy-duty installations. Most peristaltic pumps work through rotary motion, and a rotor arranged inside the peristaltic pump has a number of wipers or rollers attached to the rotor’s external circumference, which compresses the flexible tube when the wip- ers/rollers rotate by. The part of the tube under compression is closed, forcing the fluid to move through the tube. Typically, there will be two or more rollers compressing the tube, trapping a body of fluid between them, where the fluid is transported through the tube, toward the pump outlet.

Problems related to heavy-duty peristaltic pumps is for example following: The Heavy- duty construction of peristaltic pumps takes up a lot of space, because of large diameter of the rotor and tube arranged in a support frame. The peristaltic pumps are furthermore expensive in transportation because of the dimension of the pump.

Linear peristaltic pump is also known, but fare from common as the peristaltic pump. Linear peristaltic pump has often been designed, fabricated, and tested for microfluidic applications, or even as dosing or dispenser pumps.

An example of a linear peristaltic pump is disclosed in the European patent application EP0200448A2. The application discloses a linear peristaltic pump, wherein the pump comprises a deforming tube and tube deforming means. The tube deforming means moves perpendicular to the axial direction of the tube to engage and deform the tube peristaltically at axial positions successively displaced in one direction there along.

WO 2019/211782 Al also discloses a linear peristaltic pump, wherein the pump comprises a deforming tube and tube deforming means. This pump is disclosed for medical use. In heavy-duty installations, the following problem will occur during operation of a linear peristaltic pump. The tube is being deformed at a given point in the tube, and the tube will move very slowly from the almost collapsed form into the original shape. Due to the slow recovery the tube might not expand completely into the original shape. The suction capacity, and thereby the efficiency of the pump, is then greatly reduced. Over time the tube is damaged and cannot return completely into the original shape and must therefore be replaced.

Heavy-duty construction of a linear peristaltic pump is often found unstable and inefficient, followed by high maintenance costs, and therefore not preferable to use.

Object of the Invention

Consequently, it is one objective of the present invention to provide a linear peristaltic pump and a method, which addresses the above-mentioned problem and additionally provides a number of further advantages, such as stability, robustness, reliability and with a high efficiency, and which furthermore reduces maintenance and transportation costs.

One objective is to achieve a linear peristaltic pump for pumping fluid in heavy-duty installations.

Description of the Invention

The present invention addresses this by providing a linear peristaltic pump for pumping fluid, wherein the linear peristaltic pump comprises:

- a housing having a first end and a second end, at least one top part and at least one bottom part,

- a flexible tube, having an axial direction, is arranged inside the housing, wherein the tube extends from the first end to the second end of the housing, where an inlet end of the tube is attached to the first end forming a tube inlet and an outlet end of the tube is attached to the second end forming a tube outlet,

- at least one tube deforming means arranged inside the housing, wherein the tube deforming means extends from the first end to the second end of the housing, where the tube deforming means is arranged, such that the tube deforming means is capable of engaging said flexible tube and deforming the flexible tube peristaltically along the axial direction, wherein said top part and said bottom part is assembled in an airtight connection which encloses a volume inside the housing wherein the flexible tube and the tube deforming means are arranged, said linear peristaltic pump comprising means for reducing a pressure level in said volume to a predetermined pressure level, such that the pressure level inside the housing is lower relative to an ambient pressure level outside the housing.

The linear peristaltic pump is suitable for heavy-duty installations.

The flexible tube may have inner diameter of at least 20 mm in the linear peristaltic pump. Furthermore, the flexible tubes may be reinforced.

In heavy-duty installations, such as in the fishing industry or in the construction industry or mining industry, pumps are widely used. For example, in the fishing industry the pumps are used to transfer fish from one location to another location. During the transfer it is important that the fish stays intact and not get damaged. The fish may be transferred from ships into trucks and from the trucks to the fish factory using pumps. In some cases, the fish factor}' is located by the harbor, and here pumps can be used to pump fish from the ship up to the fish factory, where they are pumped to a sorting plant and then pumped into large plate freezers.

The present invention presents a linear peristaltic pump for pumping fluid, wherein the fluid may be any variation of fluid or slurries or including particles or fish etc.

Linear peristaltic pumps transport fluid through a flexible tube using traveling contraction waves. In a typical linear peristaltic pump, discrete translational elements compress successively a straight section of the flexible tube, and thereby moving fluid volumes in the tube. The linear peristaltic pumps are an example of positive-displacement pumps.

The linear peristaltic pump comprises a housing. The housing may be elongated housing. The housing is substantially airtight. The housing has a first end and a second end. The housing may be provided with at least one top part and at least one bottom part. The housing may comprise further parts forming the housing.

The top part and the bottom part may comprise sealing means such that the top and bottom part is capable of being assembled in an airtight connection. The top part and the bottom part enclose at least one volume inside the housing. The flexible tube and the tube deforming means are arranged inside the volume. The linear peristaltic pump comprising means for providing reduced pressure level in said volume relative to the ambient pressure level outside the housing. The pressure level inside the housing may be lower relative to an ambient pressure level outside the housing. The volume may even comprise a pressure level substantially equivalent with vacuum in said volume.

A flexible tube is arranged inside the housing, such that the tube extends from the first end to the second end of the housing. The flexible tubes may be reinforced, such as a hose. The flexible tube has an axial direction which may be substantially parallel to the longitudinal direction of the elongated housing. An inlet end of the tube may be attached to the first end, using means for attachment, forming a tube inlet. An outlet end of the tube may be attached to the second end, using means for attachment, forming a tube outlet. The fluid may flow through the tube inside the housing.

The tube deforming means is arranged inside the housing. The tube deforming means extends from the first end to the second end of the housing. The tube deforming means may be arranged adjacent to the flexible tube in a predetermined distance, such that the tube deforming means is capable of engaging and deforming the flexible tube peristal- tically along the axial direction. The tube deforming means engages and deforms parts of the flexible tube in a peristaltic movement.

The tube is being deformed at a given point in the tube, and the tube may move very slowly from the almost collapsed form into the original shape. Due to a low pressure level inside the housing, the tube will be forced back to the original shape very quickly, and thereby increasing the suction ability. Due to the rapid recovery, the tube expands completely into the original shape. The suction capacity and thereby the efficiency of the pump is then greatly increased. Over time the tube has an extended lifetime and maintenance costs and downtime are reduced. In an advantageous embodiment of the invention the tube deforming means comprises a rotary member having an axis of rotation substantially parallel to said axial direction.

The rotary member has an axis of rotation substantially parallel said axial direction of the flexible tube. The rotary member may be arranged substantially parallel to the flexible tube. The linear peristaltic pump may comprise means for varying the speed of rotary member rotation. Thereby varying the rotation velocity of the tube deforming means, such that said tube deforming means engages and deforms the flexible tube peristaltically along the axial direction of the flexible tube with a predefined rotation velocity.

In a further advantageous embodiment of the invention the tube deforming means comprises a helical member disposed helically to the rotary member along the axis of rotation by at least one connection means, such that the helical member engages the flexible tube and deforms the flexible tube peristaltically along the axial direction when the rotary member rotates.

The rotary member may comprise a rod. The rotary member may comprise a helical member disposed helically along the axis of rotation of the rod. The helical member may be attached to the rotary member by at least one connection means. The connecting means determines the distance between the rotary member and the helical member. The helical member is capable of engaging the flexible tube and deforming the flexible tube peristaltically along the axial direction when the rotary member rotates.

The cross-sectional shape of the helical member may be substantially curved. The cross- sectional shape of the helical member or part of the helical member may be substantially round. The helical member or part of the helical member may be similar to a tread. The part of the helical member which engages the flexible tube may be smooth such that the helical member is capable of engaging the flexible tube with low friction to avoid wear and damage of the flexible tube during rotation.

In a still further advantageous embodiment of the invention the bottom part of said housing comprises an inner recess extending from the first end to the second end of said housing, such that the flexible tube is capable of resting in the recess during deformation.

The flexible tube is resting in the bottom part of the housing. To avoid the flexible tube to be displaced during the pumping operation, the flexible tube may be arranged in a predetermined position inside the bottom part of the housing. The bottom part may comprise an inner recess extending from the first end to the second end of said housing. The flexible tube is capable of resting in the recess during deformation without being displaced. The depth of the recess allows the tube deforming means to engage and deform the flexible tube peristaltically along the axial direction in a peristaltic movement.

In a further advantageous embodiment of the invention the linear peristaltic pump comprises adjustable means in a first end and/or a second end of the tube deforming means, wherein the adjustable means is configured to vary the distance between the rotary member and the flexible tube, such that a degree of deformation of the flexible tube is varied using adjustable means.

The tube deforming means may be arranged in a first position wherein the rotary member is arranged in a first distance to the flexible tube. If the first distance is a small distance between the rotary member and the flexible tube, the deformation provided on the flexible tube is increased. Alternatively, the tube deforming means may be arranged in a second position wherein the rotary member is arranged in a second distance further away from the flexible tube, and thereby decreasing the deformation provided on the flexible tube. The distance between the rotary member and the flexible tube may be varied using adjustable means. The adjustment means may comprise hydraulic, electrical and/or pneumatic actuator or actuators.

The adjustable means is arranged in a first end and/or a second end of the tube deforming means. The adjustable means is configured to vary the pressure applied to the flexible tube using the tube deforming means. The tube deforming means may be moved toward the flexible tube, and thereby increasing the degree of deformation of the flexible tube. Alternatively, the tube deforming means may be moved away from the flexible tube, and thereby decreasing the degree of deformation of the flexible tube. The adjustable means may also be used for adjusting the most optimal distance to the recess in the bottom part wherein the flexible tube is resting. The adjusting means may also provide an easy access to the inner of the bottom part of the housing and easy access to the flexible tube. This is preferable when performing maintenance on the peristaltic pump.

In a still further advantageous embodiment of the invention the linear peristaltic pump comprises a driving unit configured to rotate the tube deforming means using rotating means.

The driving unit may be a motor which automatically rotates the tube deforming means inside the housing. The driving unit may be placed outside the housing. Alternatively, the motor may be placed inside the housing. The motor may be placed inside the housing in a part of the housing having a second volume different from the volume wherein the tube deforming means and the flexible tube are arranged. The driving unit configured to rotate the tube deforming means uses rotating means. The rotating means may comprise gearings, belt/belts or chain/chains etc.

In a further advantageous embodiment of the invention a lubricant liquid is forming a lubricant bath in the bottom part of said housing, such that said flexible tube and said tube deforming means is being disposed to the lubricant liquid during rotation of the tube deforming means.

The lubricant liquid is forming a lubricant bath in the bottom part of said housing. The lubricant liquid may cover the flexible tube and part of the tube deforming means when the tube deforming means is rotating and deforming the flexible tube. The flexible tube and said tube deforming means is being disposed to the lubricant liquid during rotation of the tube deforming means and at the same time the tube deforming means may convey an amount of lubricant liquid around in the housing, and thereby lubricate both the tube deforming means and the flexible tube constantly. The constant lubricating of tube deforming means and the flexible tube will ensure a smooth and more agile function of the pump, and thereby providing a low friction which prevents wear and damage of the flexible tube during rotation of the tube deforming means. The tube deforming means may comprise lubricant conveying means. The lubricant conveying means may be provided on the connection means and/or the helical member.

In a still further advantageous embodiment of the invention a pitch of the winding on the helical member may be less than 75% of the length of the tube deforming means.

The pitch of the winding on the helical member may be less than the length of the tube deforming means. Preferably the pitch of the winding on the helical member may be less than 75% of the length of the tube deforming means. It is important that the helical member engages the flexible tube in at least two target points at the same time, such that the return flow is reduced or preferably eliminated. The target point is the point where the helical member provides the maximal deformation of the flexible tube. The inclination of the slope of the winding on the helical member may be defined by the pitch of the windings.

The invention is also directed at a method for pumping fluid using a linear peristaltic pump, wherein the method comprising following acts: a) providing a predefined pressure level in a volume inside a housing of said linear peristaltic pump, which is lower that a pressure level outside the housing, b) rotating a tube deforming means in a predefined rotation velocity, such that said tube deforming means engages and deforms the flexible tube peristaltically along the axial direction of the flexible tube.

By providing a predefined pressure level in the volume inside the housing of said linear peristaltic pump which is lower than a pressure level outside the housing, the suction capacity will be increased.

By rotating a tube deforming means in a predefined rotation velocity, such that said tube deforming means engages and deforms the flexible tube peristaltically along the axial direction of the flexible tube. The fluid will be sucked into the tube and transported through the pump from the inlet to the outlet of the pump as the tube deforming means deforms the tube successively peristaltically. In an advantageous method the method comprises the step adjusting a degree of deformation of the flexible tube by moving the tube deforming means from a first position to a second position relative to the flexible tube using adjustable means.

The tube deforming means may be arranged in a first position wherein the rotary member is arranged in a first distance to the flexible tube, and thereby increasing the deformation provided on the flexible tube. Alternatively, the tube deforming means may be arranged in a second position wherein the rotary member is arranged in a second distance further away from the flexible tube, and thereby decreasing the deformation provided on the flexible tube. The distance between the rotary member and the flexible tube may be varied using adjustable means. The tube deforming means may easily be lifted away from the flexible tube.

The flexible tube has an inner diameter of at least 20 mm in the linear peristaltic pump. The linear peristaltic pump which may be used in larger applications, such as pumping fluid with items, fluid with fish, fluid as concrete etc. These kinds of heavy industrial applications demand a high-capacity pump for moving a large amount of fluid in a controlled manner. Alternatively, the flexible tube may have an inner diameter of at least 25 mm or 50 mm. The flexible tube may have an inner diameter of more than 100 mm. The flexible tube may even have an inner diameter of at least 300 mm. Alternatively, the flexible tube may have an inner diameter between 25 mm - 350mm or even larger. This invention presents a solution that solves the known problem and additionally provides a number of further advantages, such as stability, robustness, reliability and with a high efficiency. The solution furthermore reduces maintenance and transportation costs.

The invention has now been explained with reference to a few embodiments which have only been discussed in order to illustrate the many possibilities and varying design possibilities achievable with the linear peristaltic pump according to the present invention.

Description of the Drawing

The embodiments of the invention are described in the following with reference to: Fig. la,b: Illustrates an embodiment of an linear peristaltic pump.

Fig. 2a,b,c: Shows a cross sectional view of an embodiment of a linear peristaltic pump. Fig. 3: Shows a first embodiment of a tube deforming means.

Fig. 4: Shows a second embodiment of a tube deforming means.

In the explanation of the figures, identical or corresponding elements will be provided with the same designations in different figures. Therefore, no explanation of all details will be given in connection with each single figure/embodiment.

Detailed Description of the Invention

An embodiment of the invention is explained in the following detailed description. It is to be understood that the invention is not limited in its scope to the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways.

Figure la and lb illustrate an embodiment of a linear peristaltic pump. The linear peristaltic pump 1 comprises an elongated housing having a first end 2 and a second end 3. The housing has a longitudinal direction extending from the first end 2 to the second end 3. The housing also comprises a top part 5 and a bottom part 4. The top part 5 and a bottom part 4 are closed in a sealing manner, such that the housing is airtight. The top part 5 is pivotally attached to the bottom part by pivotable hinges 6,7. The housing also comprises fluid inlet 8 in the first end 2 and fluid outlet in the second end 3. The fluid outlet is not showed in the fig. 1 a. The arrows illustrate the flow direction of the fluid.

Turning towards fig. lb, a flexible tube 10 is arranged in the bottom part 4 of the housing. The tube might as well be a hose. The flexible tube 10 has an axial direction. The flexible tube is arranged substantially parallel to the longitudinal direction of the housing. The tube 10 extends from the first end 2 to the second end 3 of the housing. An inlet end of the tube 10 is attached to the first end 2 providing a fluid inlet 8. The tube inlet is similar to the fluid inlet. An outlet end of the tube 10 is attach to the second end 3 providing a fluid outlet 9. The tube outlet is similar to the fluid outlet.

A tube deforming means is arranged inside the housing. The tube deforming means comprises a rotary member 11, a helical member 12 and spacers 13. The rod 11 is arranged in a predetermined distance to the flexible tube 10. The tube deforming means extends from the first end 2 to the second end 3 of the housing. The tube deforming means are rotational attached to holding arms 14', 14", one holding arm in each end of the tube deforming means. The holding arms 14', 14" is each pivotally attached to the bottom part 4. One or both of the holding arms 14', 14" may comprise rotating means for rotating the rotary member 11. The tube deforming means is arranged, such that the tube deforming means is capable of engaging and deforming the flexible tube 10 peri- staltically at an axial position successively along the axial direction.

A helical member 12 is disposed helically along the axis of rotation of the rotary member 11. The helical member 12 may be attached to the rotary member 11 by at least one connection means. The connection means may be spacers 13. The spacers 13 may determine the distance between the rotary member 11 and the helical member 12. The helical member 12 is capable of engaging and deforming the flexible tube 11 peristalti- cally along the axial direction when the rotary member 11 rotates.

It should be noticed that if the rotary member 11 is rotating counter clockwise when viewed from the first end 2, the opening as described as fluid inlet 8 will be a fluid inlet. And the fluid outlet 9 will be a fluid outlet. Alternatively, if the rotary member 11 is rotating clockwise viewed from the first end 2, the opening as described as fluid inlet 8 will be a fluid outlet. And the fluid outlet 9 will be a fluid inlet. The flow direction will depend on the rotation of the rotary member 11.

The top part 5 and said bottom part 4 is assembled in an airtight connection enclosing a volume 16 inside the housing. The flexible tube 10 and the tube deforming means are arranged in the volume 16. The linear peristaltic pump 1 comprises means for reducing a pressure level in the volume 16 relative to an ambient pressure level outside the housing. The means for reducing a pressure level is not showed in the fig la and lb.

The driving unit 15, such as a motor, automatically rotates the tube deforming means inside the housing counterclockwise or clockwise. The driving unit 15 may be placed outside the housing. Alternatively, driving unit 15 or part of the driving unit 15 may be placed inside the housing. The driving unit 15 or part of the driving unit 15 may be placed inside the housing in a part of the housing having a second volume different from the volume wherein the tube deforming means and the flexible tube are arranged. The driving unit is configured to rotate the tube deforming means using rotating means. The rotating means may comprise gearings, belt/belts or chain/chains etc. Fig. 2 a,b,c shows a cross sectional view of an embodiment of a linear peristaltic pump. Fig. 2a shows the cross-sectional shape of the helical member 12 which may be substantially curved. The cross-sectional shape of the helical member 12 or part of the helical member 12 may be substantially round. The helical member 12 or part of the helical member 12 may be similar to a helical rod. The part of the helical member 12 which engages the flexible tube 10', 10" may be smooth such that the helical member is capable of engaging the flexible tube 10', 10' ' with low friction to avoid wear and damage of the flexible tube 10', 10" during rotation.

Fig. 2a and fig. 2c show the flexible tube 10', 10" is resting in the bottom part 4 of the housing. To avoid the flexible tube 10', 10" being displaced during the pumping operation, the flexible tube 10', 10" may be arranged in a predetermined position inside the bottom part 4 of the housing. The bottom part 4 may comprise an inner recess 18 extending from the first end 2 to the second end 3 of said housing. The flexible tube 10', 10" is capable of resting in the recess 18 during deformation without being displaced. The depth of the recess 18 allows the helical member 12 or part of the helical member 12 to engage and deform the flexible tube 10', 10" peristaltically along the axial direction in a peristaltic movement.

Fig. 2c is also showing that the bottom part 4 provides space for the lubricant liquid 21 by forming a lubricant bath, such that said flexible tube 10" and the helical member 12 or part of the helical member 12 is being disposed to the lubricant liquid 21 during rotation of the tube deforming means. The lubricant liquid 21 may cover the flexible tube 10" and part of the tube deforming means, when the tube deforming means is rotating and deforming the flexible tube 10". The flexible tube 10" and said tube deforming means is being disposed to the lubricant liquid during rotation of the tube deforming means and at the same time the tube deforming means may convey an amount of lubricant liquid around in the housing, and thereby lubricate both the tube deforming means and the flexible tube constantly.

The tube deforming means may comprise lubricant conveying means. The lubricant conveying means may be provided on the spacers 13 and/or in the shape of the helical member 12. The constant lubricating of tube deforming means and the flexible tube will ensure a smooth and more agile function of the pump, and thereby providing a low friction which prevents wear and damage of the flexible tube during rotation of the tube deforming means.

Fig. 2a and Fig. 2b also shows the distance between the rotary member 11 and the flexible tube 10 may be varied using adjustable means 19. The adjustment means for moving the rotary member 11 and thereby the tube deforming means may be a hydraulic, electrical and/or pneumatic actuator or actuators. The tube deforming means may be arranged in a first position such that the rotary member 11 is arranged in a first distance relative to the flexible tube 10. The tube deforming means may be moved using the adjustable means 19 into a second position, such that the rotary member 11 is arranged in a second distance, which may be further away from the flexible tube 10', 10". The tube deforming means thereby limits the deformation of the flexible tube 10', 10". The adjustable means 19 may also be used for adjusting the distance to the recess in the bottom part, preventing damage on the helical member 12 when engaging and deforming the flexible tube 10', 10".

The driving unit 12 may automatically rotate the rotary member 11 and hereby the tube deforming means. The tube deforming means are rotationally attached to holding arms 14', 14", one holding arm in each end of the tube deforming means. The holding arms 14', 14" is each pivotally attached to the bottom part 4 using pivotally attachment means, not showed on the fig 2. One or both of the holding arms 14', 14" can be pivotally moved using adjustable means 19. One or both of the holding arms 14', 14" may comprise rotating means for rotating the rotary member 11. The driving unit 12 is in communication with rotating means 20 or part of the rotating means 20, which is used for rotating the rotary member 11.

Alternatively, the motor may be placed inside the housing. The motor may be placed inside the housing in a part of the housing having a second volume different from the volume wherein the tube deforming means and the flexible tube is arranged. The driving unit is configured to rotate the tube deforming means using rotating means. The rotating means may comprise gearings, belt/belts or chain/chains etc. Fig. 3: Shows an embodiment of a tube deforming means. The tube deforming means comprises a rotary member 11, a helical member 12 and a plurality of spacers 13. The rod 11 is arranged in a predetermined distance to the flexible tube 10. The helical member 12 or part of the helical member 12 may be substantially round, similar to a helical rod. The end parts in both ends of the helical member 12 are fastened to the rotary member in transition point A and transition point B. The helical member 12 is bended smoothly in the transition point A and B, such that the helical member is capable of engaging the flexible tube 10', 10" with low friction to avoid wear and damage of the flexible tube 10', 10" during rotation.

The pitch of the winding P on the helical member 12 is less that the length of the tube deforming means. The pitch of the winding P on the helical member 12 may be less than 75% of the length of the tube deforming means. The pitch of the winding P on the helical member 12 may be less than 50% of the length of the tube deforming means. The helical member is capable of engaging the flexible tube in at least two target points at the same time. The target point is the point where the helical member provides the maximal deformation of the flexible tube 10. The inclination (p of the slope of the winding on the helical member is defined by the pitch P of the windings.

Fig. 4: Shows a second embodiment of a tube deforming means. The tube deforming means comprises a rotary member 11, a helical member 12, a plurality of spacers 13 and rollers 22. The end parts in both ends of the helical member 12 comprise rollers 22 which are fastened to the rotary member in transition point A and transition point B. The helical member 12 is bended smoothly in the transition point A and B, and the rollers 22 are capable of engaging the flexible tube 10', 10" in an agile and smooth manner, and thereby providing a smooth transition to and from the helical member 12, such that the tube deforming means still provides a low friction to avoid wear and damage of the flexible tube 10', 10" during rotation.