GB2287702A - Filling method for viscous liquids - Google Patents

Abstract

Injectors 3 are mounted in recesses (8 Fig 3) in a rotating table 9 which delivers the injectors to be filled to filling tubes 6 having reduced diameter outlets (30 Fig 6C). The filling tubes are mounted in a filling head including upper and lower mounting plates 20, 21. The tubes 6 are mounted in the lower mounting plate 21 and associated sealing plungers 25 are mounted to the upper plate 20. Each plunger 25 has a reduced diameter tip 26 and an enlarged head portion 27. The filling tubes 6 are pushed into the injectors 3 and the plungers 25 are withdrawn up through the tubes 6 allowing viscous liquid to be delivered into the injectors. When a preset quantity has been delivered into the injectors 3 the plungers 25 are driven down through the tubes 6 until the plunger tip 26 engages with the reduced diameter 30 to seal the outlet. <IMAGE>

Description

Willing Method This invention relates to a method for filling injectors with a viscous liquid such as an oily based veterinary composition.

There are considerable difficulties when filling injectors with viscous liquids such as veterinary formulations.

Because of the nature of the liquid, there is a tendency for blockages to occur when using conventional filling techniques. This invention is directed towards providing an improved method of filling such injectors.

According to the invention, there is provided a method of filling injectors with a viscous liquid comprising the steps of : mixing ingredients to form a viscous liquid mixture; heating the , mixture to a sterilising temperature and maintaining the mixture at that temperature for a preset time; delivery the viscous sterilised liquid mixture into a feed hopper of a filling machine; presenting at least one injector to be filled under a filling head having a filling tube with a reduced diameter outlet and a sealing plunger in the tube, the plunger having a reduced diameter tip; withdrawing the sealing plunger up through the tube; delivering viscous liquid from the feed hopper into the filling tube; filling a predetermined quantity of liquid into the injector;; pushing the sealing plunger through the filling tube to sealingly engage the reduced diameter tip of the plunger with the reduced diameter outlet of the filling tube; removing the filling tube from the injector; and presenting another injector to the filling tube.

A preferred embodiment of the invention wherein the fill head comprises a lower mounting plate and an upper mounting plate which are mounted on a common mounting for movement by a primary ram means between a lowered filling position and a raised released position, the filling tube being mounted to the lower mounting plate and the sealing plunger being mounted to the upper mounting plate, the primary ram means being operated to raise and lower the filling tube between the filling and release positions, and the secondary ram means being operated to move the sealing plunger between the lowered seal position and the raised release position.

Preferably the filling tube is releasably mounted to the lower mounting plate and the sealing plunger is releasably mounted to the upper mounting plate and the method includes the step of removing the filling tube and plunger from the respective mounting plates and cleaning the tube and plunger between batches.

In a preferred arrangement there are at least two filling tubes mounted side by side on the filing head for simultaneously filling into corresponding injectors located in injector receiving recesses in a filling table below the filling head.

Most preferably the filling tube is a rotary table having a plurality of peripherally spaced-apart injector receiving recesses, and the method includes the step after filling of a leading injector of rotating the table to deliver the filled injector away from the fill head and to index a following injector to the fill head for filling.

Typically, the mixture is an oil bas composition having a viscosity of from 200 to 10,000 centistokes between the temperature of 25"C to 100C.

Most preferably the mixture is sterilised by heating to a temperature of at least 1600C in the mixing vessel and maintaining the temperature for at least 120 minutes.

The invention also provided an injector whenever filled by the method of the invention.

The invention will be more clearly understood from the following description thereof, given by way of example only, with reference to the accompanying drawings; in which : Fig. 1 is a perspective view of a filling machine used in the method of the invention; Fig. 2 is a perspective view of an injector filled using the machine in Fig. 1; Fig. 3 is a perspective view on an enlarged scale of portion of the filling machine; Fig. 4 is a perspective view of a filling tube and sealing plunger used in the method of the invention; Fig. 5 is a cross sectional view of portion of the filling machine illustrated in Fig. 3; and Figs. 6(a) to 6(d) are cross sectional views illustrating the method of filling according to the invention.

Referring to the drawings, there is illustrated a filling machine used in the method of the invention and indicated generally by the reference numeral 1. The filling machine 1 comprises a feed hopper 2 for viscous liquid to be filled into injectors 3. A feed ram 2A delivers a predetermined quantity of liquid through inlet lines 5 for feeding at least one or in this case two filling tubes 6.

Injectors 3 are mounted in respective recesses 8 in a rotating table 9 which delivers injectors to be filled to the filling tubes and delivers filled injectors away from the filling tubes.

The filling machine 1 includes a filling head to which the filling tubes 6 are mounted. The filling head comprises an upper mounting plate 20 and a lower mounting plate 21 which are spaced-apart and fixed together by mountings 23.

The filling tubes 6 are releasably mounted to the lower mounting plate 21 and associated sealing plungers 25 are mounted to the upper mounting plate 20. As will be particularly apparent from Fig. 4, each sealing plunger 25 has a lower reduced diameter tip portion 26 and an enlarged head portion 27 which screw threadingly engages a mounting spigot 28 carried by the upper mounting plate 20.

Each filling tube 6 includes a lower reduced diameter outlet 30 and an upper head portion 31 which screw threadingly engages the lower mounting plate 21.

The filling head mounted on the plates 20,21 is moved upwardly and downwardly by a double acting primary ram 35.

Each of the plungers 25 is also moved up and down independently of the primary ram 35 by respective secondary rams 36.

Example The composition may comprise the following: cephalexin monohydrate B.P. 200 mg kanamycin sulphate, B.P. 100,000 I.U.

Paraffin base to 10.0 g.

The paraffin base is first sterilised by heating and then cooled to room temperature.

The balance of the ingredients are then added and mixed until a homogenous suspension is obtained.

The composition thus formed has a viscosity in the range of from 200 to 100,000 centistokes between the temperature of 25"C to 10 C.

To prepare a viscous veterinary composition for filling, the ingredients are first mixed together in a mixing vessel to form a viscous liquid mixture. The mixture is heated to a sterilising temperature of 160"C and maintained at this temperature for a preset time of at least 120 minutes. The viscous sterilised liquid mixture is then delivered into the feed hopper 2 of the filling machine 1.

A pair of injectors 3 mounted in the recesses 8 of the rotating table 9 are presented under the filling head.

This is the position illustrated in Fig. 6(a). The filling tubes 6 with the tip 26 of the plunger in sealing engagement with the reduced diameter outlet 30 of the filling tubes 6 are then pushed forwardly by the primary ram 35 into the injector 3. This is the position illustrated in Fig. 6(b).

As illustrated in Fig. 6(b) with the filling tube 6 in position in the injector 3 the plungers 25 are withdrawn up through the tubes 6 by operating the secondary rams 36 allowing viscous liquid to be delivered into the tubes 6 and through the reduced diameter outlet 30 into the injectors 3. When a preset quantity of the viscous veterinary composition has been delivered into the injectors 3, the rams 36 are operated to drive the plungers 25 downwardly through the filling tubes 6 until the plunger tip 26 engages with the reduced diameter outlet 30 of the filling tube 6 to seal the outlet and prevent further material from being delivered into the injector 3. This is a position illustrated in Fig. 6(d).

In this configuration the outlet 30 of the sealing tube 6 is fully sealed without any drips or blockages by virtue of the tip 26 to the plunger 25 driving through the tube 6 to sealingly engage the reduced diameter outlet 30 of the tube.

When the injectors 3 are filled the filling tube 6 with the sealing plungers 25 in the lowered or sealing position are raised in the direction of the arrow X in Fig. 6(b) by the primary ram 35. The table 9 is rotated to deliver the filled injectors 3 away from the filling head and to index the following pair of injectors to the filling head for filling.

The invention provides a highly efficient method of filling injectors with viscous liquids.

Many variations on the specific embodiments of the invention described will be readily apparent accordingly the invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

Claims (9)

1. A method of filling injectors with a viscous liquid comprising the steps of : mixing ingredients to form a viscous liquid mixture; heating the mixture to a sterilising temperature and maintaining the mixture at that temperature for a preset time; delivery the viscous sterilised liquid mixture into a feed hopper of a filling machine; presenting at least one injector to be filled under a filling head having a filling tube with a reduced diameter outlet and a sealing plunger in the tube, the plunger having a reduced diameter tip; withdrawing the sealing plunger up through the tube; delivering viscous liquid from the feed hopper into the filling tube; filling a predetermined quantity of liquid into the injector;; pushing the sealing plunger through the filling tube to sealingly engage the reduced diameter tip of the plunger with the reduced diameter outlet of the filling tube; removing the filling tube from the injector; and presenting another injector to the filling tube.

2. A method as claimed in claim 1 wherein the fill head comprises a lower mounting plate and an upper mounting plate which are mounted on a common mounting for movement by a primary ram means between a lowered filling position and a raised released position, the filling tube being mounted to the lower mounting plate and the sealing plunger being mounted to the upper mounting plate, the primary ram means being operated to raise and lower the filling tube between the filling and release positions, and the secondary ram means being operated to move the sealing plunger between the lowered seal position and the raised release position.

3. A method as claimed in claim 2 wherein the filling tube is releasably mounted to the lower mounting plate and the sealing plunger is releasably mounted to the upper mounting plate and the method includes the step of removing the filling tube and plunger from the respective mounting plates and cleaning the tube and plunger between batches.

4. A method as claimed in any preceding claim wherein there are at least two filling tubes mounted side by side on the filing head for simultaneously filling into corresponding injectors located in injector receiving recesses in a filling table below the filling head.

5. A method as claimed in claim 4 wherein the filling tube is a rotary table having a plurality of peripherally spaced-apart injector receiving recesses, and the method includes the step, after filling of a leading injector, of rotating the table to deliver the filled injector away from the fill head and to index a following injector to the fill head for filling.

6. A method as claimed in any preceding claim wherein the mixture is an oil bas composition having a viscosity of from 200 to 10,000 centistokes between the temperature of 25"C to 100C.

7. A method as claimed in any preceding claim wherein the mixture is sterilised by heating to a temperature of at least 1600C in the mixing vessel and maintaining the temperature for at least 120 minutes.

8. A method substantially as hereinbefore described with reference to the accompanying drawings.

9. An injector whenever filled by a method as claimed in any preceding claim.