DEVICE FOR APPLYING A FLUID

Abstract

A device for administering a fluid, wherein, with the valve opened, fluid that is to be administered can be brought through the feed channel into the cylinder, and wherein a movement of the piston counter to the first direction towards the open dispensing end generates a positive pressure in the cylinder, such that, with the first valve opened, the fluid that is to be administered from the cylinder is dispensed via the open dispensing end, wherein, in order to seal the rear end of the cylinder, a first sealing element is arranged between the piston and the cylinder and a second sealing element is arranged spaced apart from the first sealing element along the first direction. The first sealing element can be a single-acting sealing element, and the second sealing element can be a single-acting or double-acting sealing element.

Claims

1. A device for administering a fluid, comprising: a cylinder, which has an open dispensing end; a piston, which is displaceable in the cylinder between a front end position and a rear end position, and is connected to a piston rod which, along a first direction, protrudes from a rear end of the cylinder opposite the open dispensing end; a first valve closing the open dispensing end; a feed channel connected to the cylinder; and a second valve closing the feed channel, wherein, with the second valve opened, fluid that is to be administered can be brought through the feed channel into the cylinder, wherein a movement of the piston counter to the first direction towards the open dispensing end generates a positive pressure in the cylinder, such that, with the first valve opened, the fluid that is to be administered from the cylinder is dispensed via the open dispensing end, wherein, in order to seal the rear end of the cylinder, a first sealing element is arranged between the piston and the cylinder and a second sealing element is arranged spaced apart from the first sealing element along the first direction, wherein the first sealing element is configured as a single-acting sealing element, which seals off the rear end of the cylinder with respect to positive pressure in the cylinder, and wherein the second sealing element is configured as a single-acting or double-acting sealing element, which seals off the rear end of the cylinder at least with respect to negative pressure in the cylinder.

2. The device according to claim 1, wherein the first sealing element is ring-shaped and has a U-shaped or V-shaped ring cross section, and wherein an open end of the U-shaped or V-shaped ring cross section points towards the open dispensing end.

3. The device according to claim 2, wherein the first sealing element comprises a spring element, which is arranged in the U-shaped or V-shaped ring cross section and which presses two limbs of the U-shaped or V-shaped ring cross section apart from each other.

4. The device according to claim 1, wherein the first sealing element has a ring-shaped sealing part and a spring element, which subjects the ring-shaped sealing part to radially inwardly directed tensioning.

5. The device according to claim 4, wherein the ring-shaped sealing part is formed of a thermoplastic, PTFE or a PTFE compound, and the spring element is formed of an elastomer.

6. The device according to claim 1, wherein the second sealing element is configured as an O-ring seal.

7. The device according to claim 1, wherein the first sealing element and the second sealing element are arranged in a fixed position on the cylinder, such that the piston moves relative to the first sealing element and second sealing element.

8. The device according to claim 1, wherein the cylinder has a front cylinder portion and, connected releasably to the latter, a rear cylinder portion, the rear end of which forms the rear end of the cylinder, wherein the first sealing element and second sealing element are arranged in a fixed position on the rear cylinder portion.

9. The device according to claim 8, wherein the rear cylinder portion is connected releasably to the front cylinder portion.

10. The device according to claim 9, wherein the releasable connection of the rear cylinder portion to the front cylinder portion is a snap-fit closure.

11. The device according to claim 1, wherein a lubricating ring is arranged spaced apart from the second sealing element in the first direction.

12. The device according to claim 1, wherein the first valve is configured as a nonreturn valve and/or the second valve is configured as a nonreturn valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 shows a perspective view of an exemplary embodiment of the administering device according to certain embodiments of the invention.

[0032] FIG. 2 shows a front view of the cylinder/piston arrangement of the administering device.

[0033] FIG. 3 shows a sectional view of the cylinder/piston arrangement along the section line A-A in FIG. 2.

[0034] FIG. 4 shows a sectional view of the cylinder/piston arrangement along the section line B-B in FIG. 3.

[0035] FIG. 5 shows a sectional view of the cylinder/piston arrangement along the section line C-C in FIG. 4.

[0036] FIG. 6 shows an isometric view of the cylinder/piston arrangement, wherein the device is tensioned and the piston is in its rear end position.

[0037] FIG. 7 shows an isometric view of the cylinder/piston arrangement, wherein the piston is in its front end position.

[0038] FIG. 8 shows a diagram illustrating the profile of the ramp track, wherein the rotation angle α is plotted along the x axis, and the stroke along the longitudinal axis of the piston rod is plotted on the y axis.

[0039] FIG. 9 shows a sectional view of the piston/cylinder arrangement in the tensioned state according to FIG. 6.

[0040] FIG. 10 shows a side view of the piston/cylinder arrangement in which the piston is in its front end position.

[0041] FIG. 11 shows a sectional view of the piston/cylinder arrangement along the section line D-D in FIG. 10.

[0042] FIG. 12 shows an enlarged sectional view of the front part.

[0043] FIG. 13 shows an enlarged detailed view of the detail E according to FIG. 12, wherein the piston is positioned nearer the open dispensing end when compared to the view in FIG. 12.

[0044] FIG. 14 shows an enlarged view of the ring cross section in an embodiment of the first sealing element.

[0045] FIGS. 15-18 show enlarged views of the ring cross section in further embodiments of the first sealing element.

DETAILED DESCRIPTION

[0046] In the exemplary embodiment shown in FIG. 1, the device 1 according to certain embodiments of the invention for administering a fluid (e.g. a liquid) comprises a housing 2 with a main portion 3 and a handle portion 4. The handle portion 4 is designed such that a user can hold the device 1 by grasping the handle portion 4. Furthermore, the handle portion 4 has a trigger 5 for actuating the device 1. A dispensing region 6 is formed at the front end of the main portion 3. Furthermore, at the top region of the main portion 3, the device 1 has an attachment 7 to which, for example, a hose or a container can be connected. The fluid that is to be administered can be delivered via the hose. Similarly, the fluid that is to be administered can be held in the container.

[0047] At its end facing away from the main portion 3, the handle portion 4 transitions into a base 8 in which, for example, a power supply (for example an accumulator) for the device 1 can be contained.

[0048] In the exemplary embodiment described here, the device 1, which can also be designated as administering device 1, is designed for the needle-free administration of the fluid to an animal. The administration preferably involves the intramuscular injection of the fluid which, for example, can be a pharmaceutical product, a vaccine or the like.

[0049] The administering device 1 has a cylinder/piston arrangement 10 (FIGS. 3 and 4) described in more detail below and is of the self-filling type, such that a movement of the piston towards the dispensing region 6 causes a discharge of the fluid, and an opposite movement of the piston causes the cylinder to fill with the fluid for the next discharge procedure.

[0050] FIGS. 2 to 5 show the whole cylinder/piston arrangement 10 without the housing 2. The cylinder/piston arrangement 10 comprises a front part 11 and, connected to the latter, a rear part 12. The front part 11 comprises a cylinder 13 for receiving the fluid, which cylinder 13 has an open dispensing end 14 in which a first nonreturn valve 15 sits, the latter being fluidically connected to a nozzle 16. The first nonreturn valve 15 can also be seen clearly in the enlarged sectional view of the front part 11 in FIG. 12 and is designed so as to permit dispensing of the fluid from the cylinder 13 via the first nonreturn valve 15 and the nozzle 16. Suctioning of air or liquid via the nozzle 16 and via the first nonreturn valve 15 is not possible. The nonreturn valve 15 closes in this direction.

[0051] Also formed at the front part 11 is the attachment 7, in which a second nonreturn valve 20 (FIG. 12) sits, the latter permitting a fluidic connection of the attachment 7 to the cylinder 13 and blocking a fluidic connection in the opposite direction. The attachment 7 has a channel 21 (or feed channel 21) which opens into the cylinder 13 via a plurality of radial bores 22.

[0052] The second nonreturn valve 20 can be designated as an inlet valve, and the first nonreturn valve 15 can be designated as an outlet valve.

[0053] A piston 25 with a piston end 26 pointing towards the open dispensing end 14 is guided in the cylinder 13, wherein the piston 25 is in its rear end position in the sectional views in FIGS. 3, 4 and 12. In this position, the cylinder 13 is filled with the fluid that is to be administered. The piston 25 is here designed as a rod of constant cross section, wherein the part of the rod that is moved to and fro in the cylinder 13 is designated as the piston 25, and the part of the rod that protrudes rearwards from the cylinder 13 is designated as the piston rod 27.

[0054] The rear end (shown clearly in FIG. 4) of the piston rod 27 pointing away from the open dispensing end 14 is connected by a plate 28 to a first guide rod 29 and a second guide rod 30, which extend parallel to each other and parallel to the piston 25 and are guided in the rear part 12. Those ends of the guide rods 29 and 30 facing away from the plate 28 are connected to a driver 31.

[0055] Moreover, a compression spring 32, 33 (e.g. a helical spring) is arranged for each guide rod 29 and 30, the front ends of the compression springs 32, 33 each bearing on the plate 28, and their rear ends each bearing on an abutment of the rear part 12. In the position of the piston 26 shown in FIGS. 3 and 4, the springs 32, 33 are tensioned.

[0056] Arranged at the rear end of the rear part 12 is a cover 35, which is not shown in the isometric view of the cylinder/piston arrangement 10 according to FIG. 6 in order that the driver 31 can be clearly distinguished. The driver 31 has a rotatably mounted roller 40, wherein the rotation axis of the roller 40 extends substantially perpendicular to the longitudinal axis of the rod-shaped piston 25.

[0057] The roller 40 runs on a ramp track 41 of a ramp 42 that rotates under the roller 40, wherein the ramp track 41 has a single winding, as can be seen in particular in FIGS. 6 to 8.

[0058] In FIG. 8, the rotation angle α is plotted with respect to the pitch difference z parallel to the longitudinal direction of the piston rod 25, wherein it is assumed that, at a rotation angle of α0=0°, the smallest pitch height z0 is present and the piston 26 is thus in its front end position, in which the distance of the front piston end 26 from the open dispensing end 14 is minimal. This position of the piston 25 is shown for example in the sectional view according to FIG. 11.

[0059] The ramp track 41 has a lower plateau 43, which is adjoined by a region of inclination 44, the latter extending as far as the upper plateau 45. The upper plateau 45 is adjoined by a transfer region 46, which merges into a transition flank 47 (rotation angle α1), which in turn leads to the first plateau 43. The rotation angle range from α0 to α2 thus equals 360°.

[0060] The transition flank 47 is distinguished by the fact that it runs virtually vertically, since it extends from the height z1 to the height z0 at a rotation angle (here α2). The transfer region 46 is thus the rotation angle range at which the height z1 decreases continuously starting from the upper plateau 45, until the rotation angle α2 (=transition flank 47) is reached. Thus, the rotation angle range of α1 to α2 covers the transfer region 46.

[0061] The ramp 42 is connected by a coupling 50 to a motor 51 (FIG. 3) which rotates the ramp 42 in a first rotation direction 52 (FIGS. 6 and 7). If, starting from the position shown in FIG. 6 in which the cylinder/piston arrangement 10 is tensioned, the motor 51 now rotates the ramp 42 further in the first rotation direction 52 (since a user has actuated the trigger 5), the roller 40 runs over the transfer region 46 and then descends along the transition flank 47 in the direction of the lower plateau 43, since the tensioned compression springs 32 and 33 accelerate the plate 28 in the direction of the open dispensing end 14, as a result of which the piston 25 connected to the plate 28 is likewise moved towards the front dispensing end 14, and the fluid contained in the cylinder 13 is thereby discharged, via the first nonreturn valve 15 and the nozzle 16, for intramuscular injection into an animal. The administering device 1 is designed such that the fluid safely penetrates the skin and is administered into the muscle lying beneath the latter. The front piston end 26 is then in its front end position, as is shown for example in the sectional view in FIG. 11. The administering device 1 is preferably configured such that, in the front end position of the front piston end 26, the driver 31 bears on the rear end of the rear part 12, as a result of which the rear end of the rear part 12 forms an abutment for the driver 31. In this position, there is still a desired minimal distance between the roller 40 and the ramp track 41, such that the lower plateau 43 of the ramp track 41 is not reached by the roller 40. It is thus possible to prevent a situation where the roller 40, at the end of the discharging procedure, strikes the ramp track 41, which could cause damage to the roller 40.

[0062] After the discharging procedure, the ramp 42 is rotated again in the first rotation direction 52 by means of the motor 51, such that, as soon as the roller 40 makes contact with the ramp track 41 in the region of inclination 44, further rotation has the effect that the driver 31 is moved along the longitudinal direction of the piston 25 away from the open dispensing end 14, as a result of which the compression springs 32, 33 are tensioned again and reach their maximum tensioning when the roller 40 reaches the upper plateau 45. On account of the mechanical connection of the driver 31 to the guide rods 29 and 30, to the plate 28 and to the piston rod 25, this movement of the driver 31 has the effect that the piston 25 and thus the front piston end 26 are also moved in a direction away from the open dispensing end in the cylinder 13, and a negative pressure is thus built up. As soon as the built-up negative pressure is so great that the inlet valve 20 opens, the fluid is sucked through the inlet valve 20 and the radial bores 22 into the cylinder 13, such that the cylinder 13 is filled with the fluid.

[0063] When the roller 40 (which can also be designated as a cam or a barrel) has reached the upper plateau 45, the motor 51 stops, such that the cylinder/piston arrangement 10 is tensioned and therefore the administering device 1 is ready for the next administering procedure, which can be carried out by actuating the trigger 5.

[0064] The plate 28, the springs 32, 33 and guide rods 29, 30, the driver 31 with the roller 40, and the ramp 41 form, together with motor 51 and coupling 50, a tensioning device S for tensioning the cylinder/piston arrangement 10.

[0065] The administering device 1 moreover comprises a control unit 54 for controlling the motor 51 and all the other electrical components of the device 1. FIG. 3 shows a printed circuit board with the control unit 54.

[0066] In the case of the administering device 1, it is important that the rear end 60 of the cylinder 13 (FIGS. 12 and 13) is well sealed, because the intended use of the administering device 1 causes high, dynamic pressures and also negative pressure. In the cylinder 13, which has a pressure space 70, there prevails both positive pressure (upon administration of the fluid) and negative pressure (upon suctioning of new fluid for the next administering procedure). The speed of the piston 25 during the suctioning is much slower than it is during the administering. Standard O-ring seals are generally not designed for high, dynamic pressures, since such O-rings quickly become worn. In addition, abrasion of the O-ring seals can have the disadvantage of clogging the outlet valve 16, for example. This can lead to malfunctioning and, consequently, to the repair work required for the latter, and also to an undesirably higher outlay on maintenance.

[0067] A first sealing element 61 and a second sealing element 62 can be spaced apart from the latter along the first direction (from left to right in FIG. 12). The first sealing element 61 is designed as a single-action sealing element or a single-acting sealing element, which seals off the rear end 60 of the cylinder 13 with respect to a positive pressure in the cylinder 13. The first sealing element 61 can be ring-shaped and have a U-shaped cross section (or V-shaped cross section), wherein the open end of the U-shaped cross section (or V-shaped cross section) is open towards the front end 14 or the open dispensing end 14. With a positive pressure in the pressure space 61, the two limbs of the U-shaped cross section (or V-shaped cross section) of the first sealing element 61 are then pressed radially apart from each other, such that the desired sealing action can be ensured. The first sealing element 61 can have a spring element 61′ in the U-shaped cross section (or V-shaped cross section), which spring element 61′ already presses the two limbs of the U-shaped cross section (or V-shaped cross section) radially apart from each other, in order to strengthen the desired sealing action, as is shown schematically in FIG. 14.

[0068] However, since the single-acting sealing element 61 does not seal off, or only poorly seals off, the rear end 60 of the cylinder 13 with respect to negative pressure in the pressure chamber 70, the second sealing element 62 is provided. In the exemplary embodiment described here, the second sealing element 62 is designed as a double-action sealing element 62 or a double-acting sealing element 62 (it can be an O-ring seal for example), which seals off the rear end 60 of the cylinder 13 with respect to negative pressure in the pressure space 70.

[0069] Since the first sealing element 61 seals off the rear end 60 when there is a positive pressure in the pressure space 70, then, compared to previously known solutions, the pressure on the second sealing element 62 in the event of a positive pressure in the pressure chamber 70 is no longer so high, and therefore the undesired wear on such an O-ring seal 62 is greatly reduced.

[0070] Moreover, a lubricating ring 63 can also be provided which is arranged between the cylinder 13 and the piston 25. It can be, for example, a felt ring or a sponge-like material. The lubricating ring 63 can have oil or grease applied to it for example, in order to ensure the best possible lubrication of the piston 25.

[0071] In the embodiment shown in FIGS. 12 and 13, the first sealing ring 61 and second sealing ring 62 and the optional lubricating ring 63 are arranged in a fixed position on the cylinder 13, such that the piston 25 moves relative to the first sealing ring 61 and second sealing ring 62 and to the optional lubricating ring 63. It is of course also possible to arrange the first sealing ring 61 and/or the second sealing ring 62 (preferably both sealing rings 61 and 62) in a fixed position on the piston 25, such that the piston 25 moves together with the sealing rings 61 and 62. The lubricating ring 63 can also be arranged in a fixed position on the piston 25.

[0072] As can be clearly seen from the enlarged detailed view in FIG. 13, the first sealing ring 61 and second sealing ring 62 and the optional lubricating ring 63 are arranged in a rear cylinder part 64, of which the rear end also forms the rear end 60 of the cylinder 13, and which is connected to the front cylinder part 66 of the cylinder 13 by a snap-fit closure 65.

[0073] This results in a compact cylinder 13 which can be removed in its entirety from the device. This compact cylinder 13 can then be divided into its parts and, for example, only the rear cylinder part 64 along with the sealing rings 61 and 62 and the lubricating ring 63 need be replaced. It is of course also possible to replace only the first sealing ring 61 and second sealing ring 62 and the optional lubricating ring 63 during maintenance and to use the rear cylinder part 64 again.

[0074] In the embodiment shown in FIG. 15, the first sealing ring 61 is designed as a grooved ring. In this case in particular, the obtuse-angled sealing edge can have a greater angle α with the grooved-ring surface than the outer face of the sealing edge with the shallower angle β. Hard polyurethane can be used as material.

[0075] FIG. 16 shows a modification of the grooved ring of FIG. 15.

[0076] In FIG. 17, the grooved ring of FIG. 15 is modified such that it is in two parts and additionally has the elastic O-ring 61′, which presses the sealing edges radially outwards and ensures the desired pretensioning.

[0077] FIG. 18 shows a further possible embodiment of the first sealing element 61. In this embodiment, a sealing ring 61 (e.g. of PTFE or PTFE compound) is provided which has an elastomer O-ring 61′ on its outer face. The elastomer O-ring 61′ serves to press the sealing ring 61 onto the piston 25. For this purpose, the first sealing element 61 so designed sits (with the elastomer O-ring 61′) in a corresponding receiving groove in the rear cylinder part 64.

[0078] While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it will be apparent to those of ordinary skill in the art that the invention is not to be limited to the disclosed embodiments. It will be readily apparent to those of ordinary skill in the art that many modifications and equivalent arrangements can be made thereof without departing from the spirit and scope of the present disclosure, such scope to be accorded the broadest interpretation of the appended claims so as to encompass all equivalent structures and products. Moreover, features or aspects of various example embodiments may be mixed and matched (even if such combination is not explicitly described herein) without departing from the scope of the invention.