This invention is concerned with apparatus to allow the discharge of liquid from a container.

It is common to transport liquid in a rigid container lined with a liquid impervious plastic bag. The container commonly includes a side discharge port near the bottom of one container side and a discharge means is provided to allow the contents to flow from the liner bag through the discharge means.

It has been found that when the liquid level is close to the bottom of the container during a discharge operation it is not uncommon for the plastic around the discharge opening in the liner bag to be drawn into the opening and this can interrupt the free flow of liquid from the liner bag. In some instances there is a total interruption of the flow making it almost impossible to completely discharge the liquid.

In order to overcome the problem the liner bag needs to be punctured in a manner which prevents the plastic bag adjacent the puncture entering the discharge means. This has already been done by linearly forcing a generally circular ring cutter with teeth around a substantial part of the circumference along the bore of a nozzle welded to the bag. The cutter teeth sever all but a portion of the membrane which covers the bore of

the nozzle and in so doing forms a discharge opening and a flap which remains connected to the liner by the unsevered membrane portion. The flap is prevented from entering the discharge opening created by the cutter and is held out of alignment with the discharge opening by a flap retainer which projects through the discharge opening into the interior of the liner bag. The flap retainer also prevents the bag around the discharge opening entering the discharge opening.

The present invention achieves the above conditions by using a cutter which is rotated to perform the cutting operation as distinct from the known arrangement where the movement of the cutter is purely linear.

Broadly stated the invention can be said to provide a bag puncturing means which comprises a cutter support which has a threaded portion at one end of the support whereby the cutter support is can be engaged with a threaded nozzle of a bag, said nozzle has a bore closed by a cutable membrane to be punctured by said bag puncturing means, a passageway through the cutter support, a compression spring housed in the passageway, said spring having a first end disposed within said passageway whereby the spring is held captive to the support and a length such that when the spring is uncompressed a portion of said spring which terminates in a second spring end projects from the passageway

beyond said one end of the support, a membrane cutting means connected to said support so as to be rotatable with said support, said membrane cutting means includes a portion which will always project beyond said one end of said support.

Several embodiments of the present invention will now be described with reference to the accompanying drawings in which:

Fig.l is a side view of a first form of spring mounted cutter according to the invention,

Fig.2 is a side view of a second form of spring mounted cutter according to the invention,

Fig.3 is a side view of a third form of spring mounted cutter according to the invention,

Fig.4 is a side view of a fourth form of spring mounted cutter according to the invention,

Fig.5 is a side view of a fifth form of spring mounted cutter according to the invention,

Fig.6 is a side view of a sixth form of spring mounted cutter according to the invention,

Fig.7 is a side view of a cutter and spring combination according to the invention.

Fig.8 is a front view of a blade cutter according to the invention.

Fig 9 is an edge view of the cutter shown in Fig.8,

Fig.10 illustrates the cutter of Figs.8 and 9 as initially mounted in a bag nozzle prior to bag

puncturing taking place,

Fig.11 is a view similar to Fig.10 where the cutter of that arrangement is commencing to cut the membrane of the liner bag to form a discharge opening, and Fig.12 illustrates the situation after the liner bag membrane has been punctured.

Fig.l shows a compression spring 1 which has a constant diameter for most of its length and has a conical leading end 2 and a clamping coil 3 at its other end. The clamping coil 3 has a greater diameter than the body of the spring 1. A cutter 4 which moves linearly with the compression and decompression of the spring 1 in a bag puncturing operation is welded to the spring. The position of the cutter 4 is such that even when the spring is substantially compressed, as will be clear from the following description, the cutting end 24 of the cutter 4 will always be in a position to engage the membrane of the liner bag to be punctured.

In Fig.2 the conical leading end 2 of the spring 1 terminates in a larger pressure exerting coil 5.

Fig.3 illustrates the spring 1 of Fig.2, although it could be of the form shown in Fig.l, around which there is a sleeve 6 provided with a cutter 4. The sleeve is welded at 7 to the spring 1.

Fig.4 is a modified version of the Fig.3 arrangement where the sleeve 6 is replaced by a curved plate member 8 fitted with a cutter 4 and welded at 9 to the spring 1.

Fig.5 is a variation of the arrangement shown in Fig.4.

Fig.6 varies from the previous embodiments in that the cutter 4 does not move linearly with the spring during compression/decompression. The cutter 4 has a body 10 of predetermined length and it is welded to the clamping coil 3 of the spring 1.

Fig.7 shows a variation of the Fig.6 arrangement in that the cutter body 10 is replaced by a sleeve 11 provided with a cutter 4. The sleeve 11 slides over the spring body and it is provided with a rear end flange 12 which abuts the clamping coil 3.

Figs.8 and 9 show a variation of the Fig.7 cutter in that a support bar 13 is provided and the bar 13 has an out turned flange 14 at one end to abut the clamping coil 3. The bar 13 is joggled at 15 to provide the cutter 4.

Figs.10,11,12 show the operation of the cutter of the form shown in Figs.8 & 9. In a typical arrangement there is a container with a side 16 shown in part and

provided with a bag nozzle receiving opening 17. The liner bag in the container is identified 18 and the nozzle 19 is welded to the outside of the liner bag with the bore of the nozzle covering a membrane forming portion 20 of the liner bag 18.

The bag nozzle 21 has a internal threaded zone 22 to receive a threaded first end of a cutter support 23. The other end of the cutter support 23 is also threaded and it has a clamping member 24 mounted thereon. The member 24 can be part of a flow control valve, not shown. The spring 1 is housed in the bore 25 of the support 23 and the clamping coil 3 abuts the outer end of the support 3 and is clamped thereagainst by a shoulder 26 in the bore of the member 24.

It follows that as the support 23 is threaded into the bag nozzle the coil spring 1 and the associated cutter will rotate and the leading end coil 5 of the spring 1 will come to rest against the membrane 20. Continued rotation of the support 23 will cause the spring 1 to be compressed and the pressure on the membrane 20 to increase.

Eventually the cutter 4 will come into contact with the membrane 20 and the rotation of the cutter after penetration of membrane 20 by the cutter 4 will initiate a cut in the membrane 20. The cut will

continue as the support 23 is rotated further until the force applied by the spring 1 overcomes the capacity of the connection of the membrane 20 to the liner bag 18 to resist that force. When this occurs the membrane 20 (now a flap 28) will be thrust into the interior of the liner bag and the configuration of Fig.12 will be achieved. The liquid can now flow freely and the flap 28 is prevented by the spring 1 from blocking the opening through the liner bag 18.

The foregoing are descriptions of preferred embodiments of the invention and it is to be understood that changes can be made to the described arrangements without departing for the inventive concept herein disclosed and hereinafter claimed.