The present invention relates to methods and apparatuses for mixing materials, including combination materials, such as powders, gels, aqueous materials, and other similar materials. The mixing apparatus may also function as a dispensing apparatus.
Mixing materials to form a resulting combination or mixture is known, and includes various techniques such as hand mixing to electro-mechanical mixing. In certain situations, certain materials cannot be pre mixed due to storage stability issues or when one or more components react to the other or to moisture. For example, in some instances, a powder is to be mixed with a gel or aqueous material, and the powder must be maintained dry to prevent degradation, so pre-mixing is undesired. In other situations, a mixture is to be made but is to be dispensed soon after mixing or after a resting period to obtain a particular viscosity. Still further complications arise due to sterilization methods. For example, some gels may be steam sterilized because they are too easily degraded by radiation, while other materials are sterilized by radiation due to heat or moisture instability.
The mixing of two components, such as a gel and a powder, may be difficult, similar to mixing flour and water. In these instances, the outer layer of the powder wets and the inner layer of the powder remains dry, which leads to clumping and a varied concentration of the mixture. The mixing can be further hindered by the method, as too little speed can allow the mix to set quickly forming a paste, but too much speed can increase pressure pushing out moisture and creating packed powder at the bottom. Incomplete mixing creates clumps and clumps clog the mixer or the applicator/dispenser. In some instances, a dry powder may have an affinity to water, and the gel or other material includes a high concentration of water, leading to potential complications. In some situations, a phenomenon known as gel blocking can interfere with dispensing of mixtures.
The present invention seeks to resolve various issues involved with mixing components by providing an improved mixing apparatus and method for mixing. The mixing device may further include a dispensing device, thereby allowing mixing and dispensing in one device.
The present invention relates to mixing devices and apparatuses, along with components to achieve mixing of multiple components. In one aspect, there is a mixing apparatus for achieving mixing of multiple components, including a mixing chamber having a first end and second end, where the first end is open; and a mixing device secured to the first end, the mixing device including a plunger, a rod, a mixing head having a plurality of angled blades, and a device to control spin of the mixing head, where the mixing head is inserted at least partially into the mixing chamber, where the device to control spin of the mixing head causes the mixing head to spin when the plunger is moved in a first axial direction, and causes the mixing head to avoid spinning when the plunger is moved in a second axial direction.
There is also included methods of mixing, such as a method of mixing two components including having a first component and a second component into a mixing chamber having a first end and second end, where the first end is open; securing a mixing device to the first end, the mixing device including a plunger, a rod, a mixing head having a plurality of angled blades, and a device to control spin of the mixing head, where the mixing head is inserted at least partially into the mixing chamber; and moving the plunger in a first axial direction and in a second axial direction at least one time each, where the device to control spin of the mixing head causes the mixing head to spin when the plunger is moved in a first axial direction, and causes the mixing head to avoid spinning when the plunger is moved in a second axial direction.
There is also included a kit including a mixing chamber having a first end and second end, where the first end is open; a mixing device capable of being secured to the first end, the mixing device including a plunger, a rod, a mixing head having a plurality of angled blades, and a device to control spin of the mixing head, where the mixing head is inserted at least partially into the mixing chamber; a first material to be mixed; and a second material to be mixed.
In other aspects of the invention, there is provided a syringe locking system to maintain components together during a mixing process, and is suitable for various size syringes.
The present invention relates to methods and apparatuses for mixing at least two components. The two components may include, for example, powders, gels, aqueous materials, solvents, and combinations thereof. The apparatuses used may include various components, such as a mixing component, a dispensing component, various syringes, and a dispensing tip. Each of these components may be used by themselves, in combination, or as part of a kit. For example, the dispensing component and mixing component may be used by themselves in combination, or the mixing component may be used by itself.
Most materials may be mixed by the present invention by choosing and appropriate mixing blade, and in some cases, the mixing includes a first material in the form of a powder and a second material in the form of a gel. For example, the powder material may include an oxidized regenerated cellulose in the form of particles or fibers, while the gel may include a cellulose, such as carboxymethyl cellulose. Polysaccharides may be useful as the first and/or second materials. Additional components may be mixed in combination, including, for example, solvents and/or liquid carriers, such as saline. The mixer is most useful to easily mix dry material (or dry material that has been wetted with an aqueous material) with very viscous material, such as a gel or cream, which typically is not easily and thoroughly mixed. The use of an aqueous material to wet the powder aids in reducing clumping of the powder, and is therefore preferred but not required in some instances, for example, if the gel has sufficient aqueous material as part of the gel composition.
Attempts to mix a powder and viscous gel together via typical luer lock syringes have commonly failed, are extremely tedious, or are operator dependent, and even successful attempts have only been in small syringe volumes such as 10 ml and smaller. A phenomenon sometimes referred as “gel blocking” was found to prevent an easy and sufficient mixing of these two components by simply expressing one syringe into the other. When “gel blocking” occurs in the luer-lock connector, the force to move material from one syringe to another exceeds that of the human hand and cannot be undone rendering the device useless. As used herein, the term gel blocking refers to a phenomenon that occurs when the swelling of a superabsorbent polymer blocks the passage of fluid into the center of a material, thereby reducing the absorption capacity. The technical challenge solved by the present invention is to mix large and/or small volumes of a first absorbent powder (such as ORC powder) with a gel-type material (such as CMC gel) in a rapid and sufficiently complete manner immediately prior to or at the time of application (such as during a surgical procedure). It is helpful to mix these components directly in a syringe, where the syringe is to be used as the dispensing component.
Shear is a factor to consider for mixing of materials such as powders and gels. Typically shear is the result of the mixing process, resulting in a decrease of the material viscosity, which is sometimes referred to as shear thinning. However, the present mixing system has shown that mixing can be achieved either with limited shear thinning or with shear thinning level depending on the blade configuration and number of strokes used to mix. This allows creation of a thoroughly mixed ORC/CMC gel that has a very high viscosity, and conversely the same mixing apparatus and ORC/CMC mixture by using a different blade configuration may yield a lower viscosity gel. The end result provides for either a high viscosity mixture, which can then be dispensed as a thick gel using an open dispenser, or as a thin creamy gel by restricting a dispenser opening. This is interesting as well as novel and unexpected, since syringe to syringe mixing when possible will typically produce highly sheared gel, which presents as a thin creamy gel. Details of certain ORC/CMC compositions and methods of making and using certain ORC/CMC compositions may be found in U.S. Patent Application No. 62/026,148, filed Jul. 18, 2014, and U.S. Patent Application No. 62/026,156, filed Jul. 18, 2014, the entire contents of each of which are incorporated by reference herein.
The present inventive mixing apparatus and assembly and method can mix a variety of mixture concentrations effortlessly by a user in any size mixing and dispensing syringe. The inventive mixing apparatus is capable of mixing larger quantities of powder (such as ORC powder, which may be wetted with an aqueous material) and gel (such as CMC gel) easier and quicker than previous attempts. This can be achieved in smaller volumes (e.g., 5 or 10 mL) or larger volumes (e.g., 50 mL), but could be scaled up to larger sizes. Further, unlike syringe to syringe mixing, it is easier to mix larger volumes than smaller volumes in the inventive mixer. This may be partly due to the larger blade diameter having higher surface speed, and increased shear. To minimize excessive shear a more open blade structure may be used.
With reference to
A mixing device includes a threaded mixing screw 4, which extends axially along the mixing device and is connected to the hinge system 3. The threaded mixing screw 4 may be housed within a mixing housing 5, which is an axially extending, hollow cylindrical body. The threaded mixing screw 4 is preferably releasable connected to the mixing plunger 1, such that when the mixing plunger 1 is pulled axially in the proximal direction (9), the threaded mixing screw 4 is pulled in the proximal direction 9 as well. When the mixing plunger 1 is pushed in the distal direction 10, the threaded mixing screw 4 is rotates in the distal direction. Connector 11 is securably attached to the proximal end of the mixing screw 4, and includes an opening to receive a hinge pin 12, as will be described below.
Positioned through the end of the threaded mixing screw 4 axially opposite the plunger 1 is a mixing rod 7, which is a rigid cylindrical device. The rod 7 is slidable axially through the mixing screw 7 as well as the mixing body 5. At the end of the rod 7 is a mixing head 8, which will be described in greater detail below. The mixing head 8 may be generally cylindrical, but may have any cross-sectional configuration in which a blade head could spin within the mixing syringe to facilitate mixing, and is secured to the rod 7 such that if the rod 7 rotates, the mixing head 8 rotates simultaneously. If the rod 7 is moved axially, the mixing head 8 moves simultaneously. Plunger 1, threaded screw 4, mixing body 5, and rod 7 are all aligned along the axis A. The plunger 1 and mixing head 8 are connected axially, but not rotatably to each other by the hinge pin 12 and rod 7, where the rod 7 extends from within plunger 1 to the mixing head 8, and through the threaded screw 4. Plunger 1, rod 7 and mixing head 8 are therefore all capable of being moved along axis A, in the proximal direction 9 and the distal direction 10. Threaded screw 4 has an open central axis, through which the rod 7 travels.
At the distal end of the mixing body 5 is an engagement feature 6, which may be a threaded engagement. In some embodiments, the engagement feature 6 may include a male screw-type mechanism, which is designed to mate with a female threaded receiver. In other embodiments, the engagement feature 6 may include a snap-fit mechanism to mate with a companion snap-fit device. Other suitable secure features for engagement may be used.
In preferred embodiments, the hinge system 3 is set so as to engage the hinge pin 12 into the connector 11 of the threaded mixing screw 4 when the threaded mixing screw 4 is pushed in the distal direction 10 by handle 2 and the hinge pin 12 contained within handle 2. A threaded screw is mated with a threaded nut contained within the mixer which in turn creates rotation. The amount and speed rotation is controlled by the pitch of the screw 4 and mating nut, as can be seen in
Once handle 2 has been pushed in direction 10 it can be pulled in opposite direction 9. The action of pulling on handle 2 in direction 9 deactivates the hinge system 3 pulling the screw/hinge with it as well as the blade 8 and shaft 7, however since the hinge pin 12 has been disconnected from the opening in the connector 11, the screw 4 can rotate freely as it moves in direction 9 while the mixing head 8 and shaft 7 do not rotate as they too move in direction 9.
The concept of spin-down and pull-up by using a hinge system 3 has been found to provide significantly improved mixing. After numerous trials using a spin-down/spin-up method, it was discovered that the blades in the mixing head 8 would take the same path through the mixing syringe and either would not mix the dry components at the bottom of the mixing chamber with the viscous gel sitting above it, or it would require significantly more strokes (such as more than 50 or more than 100) before the components would be mixed. The challenge was to adequately disperse and mix powder during the upward movement of the handle to accelerate the mixing process. The creation of the hinge system 3 housed within the handle 1 eliminated any need for switches or levers and becomes automatic and blind to the user, while facilitating effortless mixing in as few as 5 strokes, 10 strokes, or within 20 strokes regardless of the mixture or viscosity.
In the embodiment seen in
Further, each gap 20 is smaller in circumferential size than in
In embodiments where multiple blades 15 are used, each blade may have a circumferential angle of from about 120 degrees to about 45 degrees, including angles of about 90 degrees, about 66 degrees, or about 60 degrees. The circumferential angle of the blade 15 may depend upon the circumferential angle of the gap 20 between adjacent blades 15. The blades may have any helical pitch, from about 1.0 inches to about 0.10 inches, or from about 0.70 inches to about 0.20 inches, or from about 0.52 inches to about 0.25 inches, or from about 0.40 inches to about 0.30 inches. The helical pitch of the blade 15, in combination with the blade angle, number of blades and circumferential coverage of the blades in the mixing head 8 all contribute to the total open shear area of the mixing head 8. The open shear area may be from 0.100 in2 to about 0.001 in2, and may be about 0.08 in2, or about 0.065 in2, or about 0.05 in2, for example in a mixing head capable of fitting in a typical 10 mL syringe. It is contemplated that the open shear area may increase or decrease as the diameter and overall size of the mixing head changes to be suitable for a larger or smaller mixing apparatus (such as a syringe).
It is particularly desired that the outer blade ring 25 of the mixing head 8 be sized so as to be axially movable within the syringe body 60, where the diameter of the mixing head 8 is slightly smaller than the inner diameter of the syringe body 60. In some embodiments, the diameter of the mixing head may be equal to or less than 1 mm smaller than the inner diameter of the syringe body 60, and may be equal to or less than 0.1 mm smaller than the inner diameter of the syringe body 60. It is also contemplated that mixing head 8 may have at least one radially extending flexible extension or extensions that are sized and shaped to contact and wipe the interior walls of the syringe upon axial movement of the mixing head 8. Such extensions could be aligned in the direction of travel “A” or within 90 degrees of “A”.
When the mixing apparatus and syringe are connected to each other, the mixing head 8 is disposed within the syringe body 60, and is axially movable distally and proximally by pushing or pulling the mixing plunger 1. As can be seen in
The threaded mixer screw 4, as described above, is useful in the mixing apparatus. The screw 4 has a series of threads running along its outer surface, from proximal end to distal end.
The number of revolutions may be greatly affected depending upon the screw pitch, since the smaller the screw pitch, the greater the number of rotations per axial stroke. For both 1″ & 0.4″ pitch screws, it was experienced that approximately 120 total rotations was sufficient to provide a suitable and effective mixed composition. That would be, for example, about 20 strokes for a 0.4″ pitch screw and about 50 strokes for a 1″ pitch screw. As can be seen from the chart below, a 0.4″ pitch screw could be rotated 300 times if there are 50 strokes. In some embodiments, the device should be used to mix components such that the mixing head is rotated from about 50 to about 300 rotations, or about 100 to about 200 rotations, or about 120 to about 150 rotations. The number of strokes may vary depending upon the pitch and the axial length of the device. By way of example, using a typical 10 ml syringe body of approximately 2.4″ in length, the total number of revolutions (or rotations) of the mixing head for a given number of strokes can be estimated as follows:
The present invention also includes a kit, which may include various tools and devices to be used by a user.
A kit may further include pre-filled liquid syringe 130, including a liquid material such as water, saline or other aqueous material-filled syringe. The syringe may be smaller in size than the mixing and dispensing syringe 100, and may include any desired amount of liquid material. The kit may further include a second pre-filled syringe 135, which is pre-filled with a second material, such as a gel or other powder material to be used. This second material may include, for example, a cellulose gel, such as carboxymethyl cellulose. The combination of volume from liquid syringe 130 and second pre-filled syringe 135 and materials in syringe 100 should be equal or less volume than syringe 100 can hold. The kit further includes a mixing apparatus 140, as explained above. The mixing head 8 has a circumference that is sized and shaped to be fit into and through the dispensing end 120 of the mixing syringe 100. The mixing apparatus 140 should also include an engagement feature 6, which is configured to be mated with the dispensing end 120 of the mixing syringe 100. The kit may optionally include a dispenser tip 145, which includes an engagement feature 150, where the engagement feature 150 is substantially similar to the engagement feature 6 of the mixing apparatus 140 and may include a seal to prevent leakage during mixing or dispensing. The dispenser tip 145 may include an interior dispensing lumen 155, which terminates at an orifice 160 at a dispensing end. In use, the dispenser tip 145 may be secured to the dispensing end 120 of the mixing syringe 100 to aid in dispensing of the mixed material. The dispenser tip 145 may include an attachment feature such as a standard luer-lock fitting at the orifice 160 to secure an elongated tube or catheter for delivery to an internal site, such as within a lung or other body region.
The mixing apparatus may be a compact mixing apparatus 200 where the drive screw enters the material being mixed opposed to earlier embodiment where only the shaft 7 and blade 8 are in contact with the mixture, as seen in
As can be seen in
Thus, as explained above and as seen in the various Figures, mixing heads may include any number of blades, varying blade angles, pitches, coverage and open shear area. The aforementioned four blade configurations are representative, and it is understood that variation in the specific sizes, angles and open shear area may occur.
Further, and with respect to any of the embodiments described above, the mixing chamber, such as a syringe, may have any size, and may be a 5 mL syringe, 10 mL syringe, 30 mL syringe, 50 mL syringe, 100 mL syringe, or any other size desired. The relative sizes of the mixing components may be modified to fit within any size device and achieve mixing.
The present invention is also directed to a method of mixing at least two materials, including gels, powders, liquids, and combinations thereof, however it could also be used to re-mix a pre-mixed solution prior to use if so desired. In one aspect, there is a method of mixing a gel and a powder. Optionally, a liquid material, such as water or saline, may be mixed in combination with the gel and/or the powder. Although the order of mixing may be reversed, in one embodiment, water or saline, or another thinning material, may be added to a powder component first in order to wet the powder to aid in mixing. Water or saline or other thinning material may be added to any other additional materials if desired.
In one method, a syringe is filled with the desired materials to be mixed. The syringe may be pre-filled with one or more materials, or the materials may be filled prior to use. For example, the syringe may be filled with a gel component, such as a cellulose, a powder component, such as ORC, and may include a liquid material such as saline or water to aid in mixing. The syringe piston may be inserted into the syringe and may be held in place via a locking feature during mixing.
A mixing apparatus, as described above, may be secured to the dispensing end of the syringe via locking feature, such as mated threads, snap fit, or friction fit. In this configuration, a mixing head is disposed within the body of the syringe, where the outer surface of the mixing head is the same diameter or slightly smaller in diameter than the inner circumference of the syringe body. A plunger is used to push and pull the mixing head axially, such that it moves from a distal direction to a proximal direction, and back in the distal direction a desired number of times. Through the use of a hitch mechanism, the mixing head rotates in only one direction, e.g., either the distal direction or the proximal direction, and remains un-rotated in the opposite direction (spin-down/pull-up).
As the mixing head is moved in the rotating direction, the various materials within the syringe body are rotated, agitated, and mixed by being passed through the blade gaps or holes in the mixing head. When the mixing head is moved in the opposite direction, it does not rotate, and therefore has the effect of pulling the various materials by vacuum and force, through the blade gaps and holes in the mixing head. The mixing head is moved a sufficient number of times, which may be from about 5 to about 50 series of pushing and pulling (where a push-and-pull counts as one “series”), or may be from about 10 to about 20 series. Once sufficient mixing has been achieved, which results in a mixed composition that is useful for dispensing or delivery, the mixing head may be stopped in its position, such as a proximal position. At this point, the composition is considered sufficiently mixed, and no further strokes of the mixing head are required.
After sufficient mixing to form a sufficiently mixed composition, the mixing device may be removed from the syringe. If bulk mixed material is not going to be used, either a dispensing tip or a cap may be secured to the dispensing end of the syringe. If a cap is secured, then the syringe with mixture may be stored for a desired length of time, at which time a dispensing tip may be secured to the dispensing end of the syringe. The user aligns the dispensing tip (or an elongated tube secured to a dispensing tip) with a target site, and depresses the plunger into the syringe, either through pushing or via a screw-type mechanism. This ejects the mixture through the dispenser and to the target site. If required, the mixer can be re-engaged to the syringe for additional mixing, for example, if the mixed composition has become too viscous after sitting.
The present invention, including the devices and assemblies described above, as well as the method of mixing, provides a number of benefits. In addition to manufacturing benefits, there are also provided ergonomic mixing benefits during delivery when expressing thick gels or mixtures through thin delivery devices, such as thin tubes used during laparoscopic surgery or when inserted into a bodily region such as a lung. The present invention includes a two-piece design (a delivery syringe and mixing device), which allows the use of standard syringes (for example, 10 mL syringes) to be utilized. Use of a syringe lock is useful to prevent the syringe plunger from being expelled during mixing, and then the same syringe body that was used for mixing is used to deliver the mixed composition with ease. This is because some standard syringes have small flanges, making it quite difficult to express viscous compositions. Thus, even if the syringe is a standard syringe that is not modified prior to use, a syringe lock as described herein may be applied to the standard syringe to aid in mixing and delivery of the mixed composition.
If desired, a pressurized gas can be introduced to the syringe body after the mixing has been completed, either prior to or during delivery of the mixed composition. Pressurizing the mixed composition allows for the composition to be sprayed from the syringe. In this fashion, it is useful if the mixture is thoroughly mixed, so that a spray nozzle does not get clogged with unmixed components, such as powder.
The water content of the mixture may be modified as desired to allow for a suitable thickness and water content of the mixture. For example, decreasing the water content of the gel by approximately two ml (e.g., a 4.3% by weight CMC vs. a 3.5% by weight CMC gel) can allow for a thicker, higher viscosity CMC gel which is actually more difficult to mix with a dry powder. However, by then reintroducing water or other fluid directly into the dry ORC powder at the time of mixing, the gel has a better chance of homogeneously mixing with the now-wet ORC powder and then rejoining the gel concentration to achieve a final mixed gel viscosity. This method of using lower water content gel, and introducing water or other liquid (such as saline) may be useful, and is best achieved by using the mixing system and mixing blades described above so as to create appropriate shear.
An additional element of the present invention, which may be useful in the assembly described above, is a syringe locking mechanism. With reference to
After limited success attempting various mixing methods (using powder and gel mixing), it was believed that if mixing of powders and gel was to be achieved it would be limited to at most a 5-10 mL or 10-15 mL syringe, due to force issues pushing a syringe plunger during mixing. To address these force issues, a novel two piece custom syringe plunger locking grip is provided. The syringe plunger locking mechanism provides multiple functions, including providing an ergonomic holder during mixing as well as serving as a lock that retains the syringe plunger within the syringe body during mixing. The lock also aids in a sterilization process if the gel is steam sterilized while in the syringe, to prevent expelling the gel due to the plunger being pushed out of the syringe body due to an increase of pressure inside the syringe.
An exemplary syringe locking mechanism 400 includes two components, a first component 410 and second component 420, where the first component 410 and second component 420 are shaped and sized to surround a syringe plunger 430 and flange 440 of a syringe body 450, where the two components (410, 420) are secured to each other. Each component 410, 420 includes a central opening sized and shaped to fit a syringe plunger 430 as well as a syringe body flange 440.
The device includes a central “V” shaped protrusion 411 shown in
The locking assembly 400 prevents the plunger 430 from being completely removed from the syringe body 450 or from being forced to rotate by the mixer blade. The locking assembly 400 is secured to the syringe body 450 by attachment to the flange 440. The plunger 430 is capable of being moved axially through the interior of the body 450, but is prevented from being removed from the body 450 due to the blocking plates of the locking assembly 400. During mixing, force and pressure is generated within the body 450, and the locking assembly 400 prevents unintentional removal of the plunger 430 from the syringe body 450.
A 10 ml mixer capable of spinning down (distally) and pulling up (proximally) was compared to a mixer capable of spinning down and up. Three different mixing heads, each having a unique blade configuration were tested. Blade 1 included a mixing head having six blades at a 0.25 inch pitch, where each blade is 60 degrees, with a number of raised protrusions on its blade surface, having an open shear area between the blades of about 0.022 in2. Blade 2 included a mixing head having three blades, each blade having a 120 degree circumferential angle and a helical pitch of about 0.32, having an open shear area between the blades of about 0.042 in2. Blade 3 included three blades each having a circumferential angle of about 97 degrees, having an open shear area between the blades of about 0.095 in2 and a pitch of about 0.72″. In addition, multiple screw pitches were compared in testing each mixing head, one mixer had a 0.4 inch pitch screw and one had a 1.0 inch pitch screw.
The composition mixed in each sample included about 8 ml of 4.5% 250 kD medium weight carboxymethyl cellulose, about 2 ml of saline, and about 1 gram of ORC powder with a 4:1 length to diameter aspect ratio. The mixture was expressed as a blob from a syringe, and testing was conducted using Instron testing for expression forces, which are related to viscosity. The method of characterizing complete mixing was done with visual inspection using a light box to confirm consistency of the mix throughout the syringe.
The results of the testing are set forth in the tables below:
As can be seen, for Blade 1, there was a 37% reduction in number of strokes in the spin-down/pull up as compared to spin down/spin up for a 0.4 inch pitch (or, put another way, a 60% increase in spin down/spin up compared to spin down/pull up), and a 58% reduction for a 1.0 inch pitch (140% increase for spin down/spin up). For Blade 2, there was a 60% reduction in number of strokes in the spin-down/pull up as compared to spin down/spin up for a 0.4 inch pitch (a 150% increase for spin down/spin up), and a 65% reduction for a 1.0 inch pitch (175% increase for spin down/spin up). This blade type appeared to require the least amount of strokes and also provided the highest resulting viscosity. Finally, for Blade 3, there was a 70% reduction in number of strokes in the spin-down/pull up as compared to spin down/spin up for a 0.4 inch pitch (235% increase for spin down/spin up), and a 57% reduction for a 1.0 inch pitch (190% increase for spin down/spin up).
As can be seen, regardless of blade type, the use of the spin down/pull up configuration provided significant benefit as compared to a mixer that spins in both the up and down directions. In addition, for the spin down/pull up design, there was an increased benefit regardless of screw pitch, as compared to spin down/spin up. The detailed design and concept described above may be scaled to any desired size syringe or range of syringe sizes, and as noted above, different blade configurations may be used.
It was found that the device using a spin down/pull up design resulted in about 37-70% lesser required strokes for full mixing across different blade designs and different pitches with a 0.4 inch pitch screw. The Spin down/pull up syringe design resulted in about 57% to 65% lesser required strokes for full mixing across different blade designs and different pitches with a 1.0 inch pitch screw. The spin down/spin up design was seen to become less effective as the blade open shear area was increased. The spin down/spin up design is believed to be less effective than the spin down/pull up design, since the blade takes a similar path through the gel in both the up and down directions. By contrast, the spin down/pull up configuration disturbs the gel by forcing it to move through the shear areas of a non-rotating blade in the pull up movement.
It is believed that a larger syringe mixer (such as a 50 ml syringe mixer) will mix as quick or even quicker than a 10 ml syringe mixer given the same blade and screw pitch, due to increased blade diameter having a faster circumferential speed, thus increasing shear and potentially decreasing mixing time.
The testing conducted showed less clogging and jamming, and it was found that the force to operate the present syringe mixer is low, and does not increase as syringe volumes increase. Further, while traditional syringe to syringe mixing of powders and gels generally necessitates smaller and consistent sized particles, the inventive mixing apparatus allows mixing of powders and gels that is not limited to finely ground powders, does not need consistent sized particles, and is not operator dependent. Therefore, the inventive mixer provides an easier, more effective mixer, with less force required and less risk for operator error.
The present application claims priority to U.S. Patent Application No. 62/026,131, filed Jul. 18, 2014, the entire contents of which are incorporated by reference herein.
Number | Date | Country | |
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62026131 | Jul 2014 | US |