Non Surgical Mulesing Applicator

Field of the Invention

The present invention relates to applicators of chemical or biological agents, and more particularly, to an applicator that is adapted to dispense a liquid, by regularly spaced injection, into a subcutaneous area.

Background of the Invention

The practice of mulesing has traditionally been conducted in Australia, on merino sheep to remove folds of skin from the back legs and adjacent to the anus and under the tail. The practice has been used to minimize accumulation of faeces and urine in this area that can lead to the sheep being fly-blown.

The method to remove the skin has conventionally involved the use of hand shears to cut away strips of skin from the animal's back legs. The result is considered painful to the animal and has an unacceptable visual appearance. This practice has been officially banned in the United Kingdom and voluntarily banned in New Zealand. There has been negative publicity concerning the practice.

Alternative systems of chemically removing the skin have been evaluated. In particular, sclerosing agents have been developed and tested in in-vivo trials, as described in the applicant's prior PCT/AU2006/000197, incorporated here by reference.

The injection of chemical into the skin of animals and humans has traditionally encompassed the use of needles with syringes and needleless injectors that incorporate pressure systems (hydraulic, pneumatic, mechanical). In general, pressure systems include components specifically manufactured for the purpose of injection.

Needleless injection heads to date lack mechanisms to determine the distance the injecting heads have moved over the surface of the skin or regulate the injection of fluid into the skin at predetermined spacings.

Additionally, the prior art lacks means for controlling that the correct volume of chemical is injected at the correct position in or on the skin.

A rotating wheel that either mechanically or electronically controls a delivery response in the injection head depending on how far the rotating

device has turned might be used but disadvantageously presents an opportunity for the wool to be caught or enmeshed in the device or the axle as it rotates.

Object and Summary of the Invention

It is an object of the present invention to provide a mechanism of controlling the application of biological or chemical agents, whereby the spacing between or timing of injections maybe manual or automated.

It is an object of the present invention to provide a mechanism of controlling the application of biological or chemical agents by using an optical sensor.

It is another object of the present invention to provide a mechanism of regulating the pressure and the quality of sterile fluid in a needleless injection head utilizing a pressure system.

Brief Description of the Drawing Figures

In order that the invention be better understood, reference is now made to the following drawing figures in which:

Fig.i is an elevation view of a needleless mulesing applicator;

Fig. 2 is a perspective view of a hydraulic system;

Fig. 3 is a perspective view of a hydraulic hose, a solenoid valve, a handle, a needleless injection head, and an optical sensor; Fig. 4 is a perspective view of the hydraulic hose, the solenoid valve, and the needleless injection head;

Fig. 5 is a perspective view of the carriage and optical feedback systems;

Fig.6 is an exploded perspective cross-sectioned in the AA' plane of the carriage; and Fig. 7 is an exploded perspective of a needleless injection head.

Best Mode and Other Embodiments of the Invention

The present device relates to needleless injection utilizing a head that preferably delivers multiple simultaneous doses. The dose pattern delivered

by the device is preferably controlled with an optical sensor that scans an animal's skin. Information from the optical sensor allows an operator to deliver a relatively even pattern of injections over an area of skin. It is understood that components with other specifications than those disclosed may be used, subject to factors such as preference, cost, application, and availability. Thus the only constraint on the choice of components is that they be compatible with the prescribed injection requirements. It will be understood that the dose and injection pattern control aspects of the invention are applicable to a wide variety of needleless and needle type injection devices. Similarly the needleless injection head technology disclosed may be used with or without the specific dose and pattern control apparatus disclosed herein. The following example pertains specifically to the application of the sclerosing agent sodium lauryl sulphate (SLS) fluid in non surgical mulesing, as described by the inventor in the application PCT/AU2006/000197. It is understood that the present invention may be used in any circumstances where needleless injections are required, for instance, for treatment or prevention purposes.

Referring to Fig.i, the non surgical mulesing applicator (or "applicator") comprises a delivery apparatus controlled by a handle 108 and a supporting hydraulic system 102 that delivers the SLS fluid, through a hydraulic hose 103, to the delivery apparatus. The delivery apparatus uses a solenoid valve 104 to control the delivery of doses to a needleless injection head 105. Fluid flow to the needleless injection head 105 may be linked to a dosage pattern regulator 106 which may include an optical sensor. The wires between the handle or solenoid valve and the optical sensor may be concealed by a tension spring 107 that curves as it extends between e.g. the solenoid valve 104 and the dosage pattern regulator 106. This tension spring 107 exerts a force away from the handle 108 to keep the dosage pattern regulator 106 biased against the injection surface (the skin or fleece of the sheep). A DC power supply 101 preferably powers the solenoid valve 104 and the dosage pattern regulator 106. Hence the solenoid valve 104 and the dosage pattern regulator 106 should have similar electrical specifications.

Referring to Fig.2, the hydraulic system 102 includes a standard hydraulic cylinder 201 (that acts as a pressure vessel), with screw threads

formed on one end of the exterior of the cylinder. A cover or an end-cap 202, with a hydraulic style internal thread matched to the threads on the cylinder, can be screwed on. An end-plate 203 is welded to the un-threaded end of the hydraulic cylinder 201, creating a closed and sealable chamber 204. The assembly of the aforementioned parts (hydraulic cylinder 201, end-plate 203, and end-cap 202) comprises the major components of the pressure vessel.

The pressure vessel houses a preferably gamma-ray sterilized internal bag 205 of a size between 250mm and 5 litres. This internal bag 205 is filled with SLS solution, for example, by an Australian Pesticides and Veterinary Medicine Association (APVMA) or Therapeutic Goods Association (TGA) registered manufacturer, and is detachably connected to the end-cap 202 by a cap-bag coupling 206. In this example, the internal bag 205 may be a standard intravenous bag, available in various configurations from a number of manufacturers. Such bags are made from an ethyl γinyl acetate (EVA) material, for preservation against decomposition caused by the SLS fluid. In other embodiments, different configurations and materials for the internal bag 205 may be used, as long as the material chosen does not react with the content, and the configuration fits inside the hydraulic cylinder 201.

In this embodiment, the internal bag 205 is immersed in a liquid such as water or glycerol, preferably above 13 ⁰ C, in the hydraulic cylinder 201. This arrangement minimizes the air quantity needed to pressurize the internal bag 205, and further ensures that in the event of cylinder failure, the amount of pressurized air released is only equal to the volume of the SLS solution expelled out of the internal bag 205. The size of the hydraulic cylinder 201 is thus dependent on the size of the internal bag 205, and on the amount of immersion liquid required. The temperature limitation avoids chemical precipitation of the SLS, and further avoids localized pain which may be caused by the SLS fluid at low temperatures.

Referring to Fig. 2, the end-cap 202 further has attached to it several fittings, with corresponding detachable couplings. One fitting on the end-cap 202 is the incoming gas pressure regulator comprising a gas valve 207 and a relief valve 208. The pressure regulator is attached on one end, via a flexible hose 209 to a standard gas supply cylinder 220. On the other end of the pressure regulator, the flexible hose 209 goes through the end-cap 202 and

supplies the closed chamber 204 comprising the pressure vessel. The gas cylinder may hold various gases commonly used, but preferably holds nitrogen to minimise the risk of explosion.

Another useful fitting on the end-cap 202 is the electrical or mechanical fluid pressure gauge 210. The fluid pressure gauge 210 is connected to the hydraulic hose 103. An air-venting valve 211 is preferably further attached to the hydraulic hose 103 (and above it) by a removable coupling. In some embodiments, there may be another air-venting valve attached to and above the hydraulic hose 103 at a location of closer proximity to the injection head 105 than to the pressure vessel. The air-venting valve(s) 211 are used to purge excess air from the hydraulic hose 103, and to avoid the formation of foams that may be a hazard in the work-place.

The hydraulic hose 103 delivers the fluid agent from the bag in the pressure vessel to the solenoid valve 104, and is preferably made from standard flexible stainless steel with a VITON™ liner. Other materials may be used, given they do not react with the chemical or biological agents to be delivered. The length of the hydraulic hose 103 is not critical, as long as it is sufficient to allow for easy operation of the injection head 105, but not too long that there is a significant amount of the SLS fluid washed away when hose is being cleaned. In the present embodiment the hydraulic hose 103 is 1.2m in length.

To pressurize the pressure vessel, the relief valve 208 is closed and the gas valve 207 is opened. The internal bag 205 is subsequently compressed, sending the SLS fluid contained within to go through the pressure gauge 210 and into the hydraulic hose 103. To depressurize the pressure vessel, the gas valve 207 is closed and the relief valve 208 is opened, allowing the gas to be discharged.

The fluid pressure gauge 210 is used to monitor the pressure applied to the internal bag 205. This pressure is usually within an operating range of about 600-900 KPa, but is dependent on the dimensions of parts used in the injection head, and on the volume and viscosity of the fluid injected. When the internal bag 205 is empty, the pressure shown by the pressure gauge 210 will drop to zero, indicating to the operator that the internal bag 205 should be changed.

Referring to Fig. 3, the solenoid valve 104 is attached to the handle 108, and is electrically connected to the dosage pattern regulator 106 by leads that pass through the tension spring 107. The dosage pattern regulator is further connected to the injection head 105 by a removable link or coupling 503. The injection head 105 can thus be moved along a surface by an operator holding the handle 108, the dosage pattern regulator trails comfortably behind the head 105 and sends real-time optical signals to the solenoid valve 104.

The real-time optical signals are transmitted by a feedback- wiring 302 that is fitted through the centre of the tension spring 107, and sent to the solenoid valve 104. The feedback-wiring 302 is thus protected inside the tension spring 107, and hazards such as tripping or tangling may be avoided. The power supply wiring for the optical sensor is also fitted similarly, and connected to the power supply 101.

In another embodiment, a wireless transmission, similar to Bluetooth or for example the wireless technologies used for computer mouses, may be used between the dosage pattern regulator 106 and the solenoid valve 104. Referring to Figs. 3 and 4, the tension spring 107 is preferably a coil spring. On both ends of the tension spring 107, there may be bayonet fittings which preferably have threaded sections, so that the tension spring may be affixed into corresponding holes in the solenoid valve 104 and the dosage pattern regulator 106. This affixation imposes a curve 303, thus creating a bias, in the tension spring, that urges the sensor away from the handle 108

The hydraulic delivery hose 103 is connected to the solenoid valve 104 by a hollow standard 316 SS elbow 304 but other standard 316 SS shelf fittings such as tees and straight connectors may be used. On the underside of the solenoid valve 104, the removable coupling 301 is preferably located at a site diametrically opposite the entry site of the hydraulic hose 103.

The SLS or other fluid is delivered from the hydraulic hose, via the removable coupling 301, to the injection head whenever the solenoid valve 104 is opened.

The solenoid valve 104 regulates the flow of the fluid based on the time that it is open. The actuation of the solenoid valve 104 can be controlled a dosage pattern controller. The dosage pattern controller may be a number of electronic devices, including computer controlled systems, programmable

logic controllers, or other specialized electronic components. In a preferred embodiment, this electronic control will be based on a signal from the optical sensor within the dosage pattern regulator 106. Preferably, there is a protective circuitry box 305 that covers these solenoid-control components and any wiring to and from the solenoid valve 104. The leads from the solenoid may have a range of configurations, including spade, conduit, and hazardous location. The present embodiment uses moulded leads.

Referring to Figs.3 and 4, the handle-connection side of the solenoid valve 401 has two threaded openings 402 and 403. These may be used to secure the handle. There is also a threaded nut 404 behind the mounting bracket 405 that aligns with a through-hole 406 on the mounting bracket 405, whereby the mounting bracket 405 is bolted to the solenoid valve 104.

Preferably, the mounting plate 405 has a wire through-hole 408, so that the electrical wiring within the tension spring 107 can be fitted through the mounting plate 405 and connected to the power supply 101 or to the wiring from the solenoid 104 (depending on wiring configuration). There may further be a fitting 409 on the mounting plate whereby the tension spring 107 is attached. For example, it may be a standard bayonet fitting with a threaded section. The handle 108 has two bolts (not shown) that cooperate with the threaded openings 402, 403 on the solenoid valve 104. The handle 108 and the solenoid valve 104 are thus connected to each other, and are in length-wise alignment.

As shown in Fig.3, there is a trigger or switch 306, preferably waterproof, situated at a convenient location on the handle 108, for example, on the underside of the handle 108, where the fingers of the operator are likely to rest. The operator uses the switch 306 to activate the optical sensor, adjacent to the injection head 105. The sensor electronics, rather than the direct action of the trigger, activate the solenoid. Accidental actuation of the solenoid valve 104 may thus be reduced by activating and disabling the optical sensor with the switch 306. A push-button momentary switch is depicted here, but other types of switches may be used.

It is understood that a number of different mechanisms of attachment may be used to connect the handle and the solenoid valve. It is also

understood that the handle may include features such as finger-grooves or end-plates for the convenience of the operators. In another embodiment, there may further be a manual safety switch on the handle, for the manual shutdown of dosage pattern regulator 106, the solenoid valve 104, or both. Referring to Figs. 3 and 5, the injection head 105 is attached, preferably rigidly, to the solenoid valve 104 using a removable coupling 301. The injection head 105 further has a manifold block 501 with a detachable injection plate 502 directly beneath it. Trailing behind the injection head, the dosage pattern regulator 106 is attached by a mechanical linkage such as a floating two-joint pivot with side plates 503.

The dosage pattern regulator 106 comprises a floating carriage or case 504 that houses an optoelectronic sensor. Sensors of this type work by taking successive images of the surface they are run over. A light source such as an LED shines onto a surface, e.g. skin. Changes between frames over time are processed and translated into x-y movement data. The reflection from this surface is sent to an image receiver, akin to a camera. The receiver converts the images received into a signal that indicates movement of the device over a surface. This signal can be used to measure distance travelled along a single axis and the travelling speed, and can be used to control the operation of the solenoid valve 104. Preferably, the sensor further comprises an alarm, for example a green alert LED that is activated when the calculated travelling speed is within a pre-established acceptable range.

The linkage 503 allows the sensor within the dosage pattern regulator 106 to conform to the rise and fall of a skin surface and pivot relative to the head 105. It may be run over skin in both directions while maintaining a relatively constant distance and parallelism between the sensor and the head. Preferably the floating carriage 504 is a sealed rigid plastic box. The base of the floating carriage 504, preferably a clear plate, defines the side that comes in contact with the surface on which distance travelled is to be measured (i.e. measurement surface, or in this example, the skin or fleece of sheep). One side, the floating carriage neighbours the manifold block 501, whereas the opposite side has attached to it the tension spring 107.

The following paragraph(s) describe how the signals produced from the optical sensor are used to control the solenoid valve 104.

The optical sensor can measure distance travelled in two axes, but in this embodiment only the distance travelled along one axis (forward and aft or backwards) is used in measurement calculations. The optical sensor can measure travel motion in both the forward and backward (aft) directions along an axis. The circuitry that drives the solenoid can be programmed to turn the solenoid off when the head is moving in the backwards or aft direction. This prevents an area from being injected in both directions of travel, even when the trigger is depressed. The circuitry may also disable the solenoid when travelling forward over a patch of skin that has been injected in a previous forward pass. In this way the operator can adopt a forward and aft movement of the head and still make regularly spaced injections, along a length of skin, without overlapping or repeating injections in a particular section. This 'memory' is only valid while the button is depressed.

To activate the optical sensor, the operator turns on the switch on the handle 306, and keeps the switch in the "on" position to maintain activation. When the sensor that is originally in a resting position senses travel in the forward direction exceeding a pre-set minimum (e.g. imm), the dosage pattern controller sends an initial electronic pulse to actuate the solenoid valve 104. The requirement of the pre-set minimum is made so that the effect of noise, such as hand-tremor, can be reduced.

Preferably, the dosage pattern controller sends more electronic pulses at fixed distance intervals (e.g. a pulse with a 50ms period at every 10 mm) that constitute first spacing parameters. In another embodiment, the dosage pattern controller may incorporate an electronic system that regulates the temporal or spatial frequency of activation of the solenoid valve. This electronic system may further incorporate monitoring of the flow and pressure of the fluid injected into the sheep skin. In some embodiments, the operator can see whether the sensor is being moved too fast by checking if a green alert LED is lit. If the green LED is off, the travelling speed has exceeded an acceptable maximum. In another embodiment, the optical sensor only sends the electronic pulses to activate the

solenoid valve when the travel is within an acceptable pre-programmed range of speed (i.e. only when the green LED is lit).

At each activation by one electronic pulse, the solenoid valve 104 may start opening in a series of solenoid pulses for a prescribed amount of time, at a prescribed solenoid movement speed. The solenoid pulse length, solenoid pulse interval, and solenoid movement speed may be selected by a range of toggle switches. In other embodiments, there may be dials or electronic systems used to select these second spacing parameters of solenoid movement. The following paragraphs describe the injection head 105.

Referring to Fig. 6, the head or manifold 501 is preferably a machined metal block that may be symmetric about a central transverse axis 601 lying on the AA' plane. The dimension of the manifold 501 along this axis is defined as the width. An entry port 602 is formed by a recess extending approximately half-way into the manifold 501 with a long axis that is perpendicular to the central axis 601. This entry port 602 is made to receive the removable fittings 301 and is centrally located on an entry-face of the manifold 603. In this example, a number of identical recessed exit ports 604 are evenly spaced along the central axis on an exit-face 620 directly opposite the entry- face 603. Three exit ports 604 are included in this embodiment, but there may be a different number of exit ports in other embodiments. Parallel rows or arrays of exit ports may be provided. The examples illustrate a linear array that is evenly spaced but the invention is not limited to this array.

Each exit port 604 is perpendicular to the central axis 601, and extends into the manifold 601 so that an O-ring 605 may be inserted into the resulting recess 606 (or "O-ring recess"). The O-rings 605 are used to prevent leakage of the fluid betλveen the manifold 501 and the injecting plate 502.

The entry port 602 opens into a width-wise fluid distributor 607. The distributor 607 is drilled from one end of the manifold, and spans most but not the entire width of the manifold. Towards the centre of the manifold, each exit port 604 narrows into an exit-tunnel 608 beyond the O-ring recess. The exit-tunnel 608 also opens into the distributor 607.

There are two holes 609, one on each of the two faces at opposite ends of the manifold. These holes are used by the pivot joints of the sensor linkage

503.

Referring to Figs. 6 and 7, like the manifold 501, the injection plate 502 is symmetric about a central transverse axis 610 which lies on the AA' plane. The injection plate 502 has a base 611 and two guide wings 612. The two guide wings 612 are preferably at an angle of about 45 ⁰ to the base 611. The guide wings 612 may take different angles to the base 611, as long as they can assist the base 611 to smoothly pass over obstacles such as wrinkles or wool on the measurement surface. The guide wings 612 may have spaced comb teeth, or a comb-like fitting, to separate wool fibres into discrete bundles, to facilitate operation.

There are a number of domes 613 on the injection plate 502, each aligning with one exit port on the manifold 501. An array of through -holes 614 are evenly spaced on the base 611. These through-holes 614 are used with bolts 701 for the injection plate 502 to be bolted to the manifold 501. The evenly spaced lay-out of the through-holes 611 ensures an even distribution of loading around the O-rings 605. This arrangement also spreads out the loading of the injecting plate 502 against the skin, and reduces the amount of injected fluid that may enter the intra-dermal layer. By increasing the area of the base 611, or the load area, it is less likely for the operator to inadvertently compress the skin, and in so doing decrease the volume of the fluid injected. In some embodiments, there may be extra washers under the bolts 701, to increase the distance between the bolt head and the base 611, so that the dome loading may be adjusted.

Each dome 613 is preferably a half-sphere or partial sphere, and has formed in it a laser-drilled circular injection orifice 615 through which the fluid is injected into the skin. The array of injection orifices 615 should be touching or close to the skin during the activation of the solenoid valve, so that the injected fluid can penetrate the skin. The diameter of the injection orifice 615 is critical to the flow rate, and depends on the pressure and the viscosity of the injected fluid. Other dome shapes are contemplated.

In other embodiments, the injecting plate may have injectors (and hence injection orifices) that are arrayed in a specified pattern, so that the

injection of the specified fluid results in partial or complete necrosis of the sldn, or the diminution of follicles from the skin. In this way, it is possible to increase an area of sldn that is at least partially devoid of wool or hair fibres. There may further be scar tissues in the selected area, as a result of the chemical injected. Thus it is conceivable that other embodiments of the present invention may be used as a tool to brand the animals.

Where the preceding paragraphs describe the general relationship between and geometry of components of the present invention, the following paragraph lists, by example, the components used in the construction of the embodiment disclosed above. This list is not to be understood as being limiting. l. The hydraulic cylinder 204 is 125mm in diameter and 400mm in length for a iL internal bag 203. A size suggestion for a 3L internal bag is 150mm diameter and a 500 mm length. 2. The internal bag fitting 209 is a bayonet ¹ A inch BSP thread 316 stainless steel (SS)

3, The hydraulic hose fitting 207 is made of ¹ A inch BSP thread 316 SS

4. The pressure regulator 211 is a COMET Hi Pressure regulator 310 347 for nitrogen with a type 60 connector. ■ 5. The solenoid valve 217 is a 12 volt high pressure valve with a response time of 8 to 18 milliseconds, and has a 316 SS body that is two-way normally closed, and has two 6.4 mm UNF thread openings 402 403 on the handle-connection side 401. The solenoid valve 217 further has electrical specifications of 11 watt and 12 volt, a VITON™ seal, 1.2mm injection orifice, and a 1/8 inch NPT female port. 6. The handle 302 is made from 40mm PVC pipe with a standard end cap, with two 6.4mm UFN bolts through the end-cap. 7,- A range of suitable and commercially available switches can be used as the push-button momentary switch 501, for example, the SPST large waterproof momentary switch from Jaycar Catalogue number SP-0732.

8. The connection fittings 601 between the solenoid valve and the injection head are 1/8 inch UNF SS.

9. The manifold 602 is made from 316 SS, 41mm long, 22mm wide, and 15mm high.

10. The exit ports 704 are spaced 12mm apart.

11. The O-rings 705 are AS568A-10. 12. The injecting plate 605 is a pressed imm 316 SS plate.

13. The base 802 is 41mm long and 22mm wide.

14. The guide wings 803 are 6mm wide and 41mm long, and set 45° to the base.

15. The domes 804 have a radius of 4.3mm. 16. The diameter of the dome's injection orifice is 0.17mm.

17. The bolts on the injecting plate are round headed SS.

18. The sensor linkages 503 are joining plates from motorcycle chains.

19. The OMS sends electronic pulses to the solenoid at every 10mm, for 50ms. 20. The speed range for the OMS travel is less than ioomm/3sec.

21. The possible solenoid pulse length are from 6 to 13 ms. 22. The possible pulse intervals are 1.5 to 5 seconds per 100mm, at 0.5 second increments.

23. The possible solenoid movement speeds are 0.04, 0.05, o.oό, 0.07 seconds per 100mm of forward movement.

24. The optical sensor has the following specifications: a. External power voltage of +12 volt regulated DC. b. External power current of 0.1 amps DC continuous. c. Optical sensor is Agilent™ ADNS2051 d. Distance resolution of sensor is 0.056mm

25. Processor is a Motorola™ 68HC908GP32 with 32K ROM and 512 bytes RAM.

While the present invention has been disclosed with reference to particular details of construction, these should be understood as having been provided by way of example and not as limitations to the scope or spirit of the invention. In particular, the invention has been disclosed with reference to various hose and coupling details. It will be understood that detachable couplings provide for ease of assembly and maintenance etc., but are not

considered essential components of the invention against the backdrop of the known art. Similarly the construction disclosed above relies on a control box that houses a power supply and centralised electronic components and electronic connections as required by each of the sub-components that require control signals or power. This allows components to be easily disconnected, services or replaced etc. but the precise wiring arrangement is not essential to the invention against the backdrop of the known art.