GB2248796A

GB2248796A - Ultrasonic welding in pouch manufacturing

Info

Publication number: GB2248796A
Application number: GB9117497A
Authority: GB
Inventors: Jean Marie Denis; Patrick Devos
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1990-08-13
Filing date: 1991-08-13
Publication date: 1992-04-22
Anticipated expiration: 2011-08-13
Also published as: GB9117497D0; HK1000084A1; GB2248796B

Abstract

Pouch containers which are sealed by ultrasonic welding can be severed one from the other using the ultrasonic sealing unit to sever the film after sealing the film. This can be done by the energy director on the ultrasonic horn having sidewalls of a given angle and by increasing the pressure of the ultrasonic horn against the anvil. <IMAGE>

Description

ULTRASONIC WELDING IN POUCH MANUFACTURE This invention relates to an apparatus and a method for the manufacture of filled pouches from films using ultrasonic welding. More particularly, this invention relates to the use of an ultrasonic sealing assembly to form pouches through the sealing of seams of films and also for cutting the films to form the individual pouches.

There are various techniques that can be used to form pouches from films. Regardless of the technique, seals will have to be made. The flat film must be manipulated to provide both a front portion and a back portion. This can be done in many ways. One convenient way is to first form the film into a tube and then to form the tube into a pouch. An advantage of the technique of forming the film into a tube, and then forming the tube into a pouch is that in the process of the formation of the tube into a pouch, the pouch can be filled. There are advantages to forming and filling the pouch in the same sequence.

Films can be sealed to form pouches using various techniques. Adhesives can be used to form seals. A heated platen can be used to seal thermoplastic films.

Dielectric heating, also known as radio frequency (RF) heating, can be used. However, the use of ultrasonic sealing has advantages over any of these techniques, and particularly in form/fill sequences. When adhesives are used, there are solvent removal problems.

There are also required cure times. The use of a heated platen is not efficient since the film must be heated by conduction. In RF energy heating, the full thickness of the film is heated rather than the film surface. This provides good sealing but is restricted to films that absorb a sufficient amount of RF energy to soften. Also, since the full thickness of the film is heated, there is the potential for overheating the film and depositing pieces of film, known as flash, onto the electrodes. This will affect subsequent seals made by the electrodes until they are cleaned.

It has been found that the use of ultrasonic sealing for forming pouches from thermoplastic films is an improvement over the use of adhesives, heated platens or RF energy. In ultrasonic sealing, only the surfaces that are to be bonded are heated. They are heated by absorbing impact energy. The full thickness of the film is not heated. This provides for various advantages. Films that do not have a sufficiently high absorption for RF energy can be used to make the pouches. The problem of flash formation is also obviated. Due to the heat being formed only at the impact surfaces, flash will not be produced.

It has also been found that the use of ultrasonic sealing has distinct advantages in form/fill operations. These are operations where the pouch is filled as it is formed. A problem with form/fill operations for pouches is that during the filling sequence, there is a tendency for the product to contact the area of the pouch that is to be sealed. In other types of sealing, including RF sealing, this can produce weakened seals. However, in ultrasonic sealing there is a cleaning of the surfaces that are to be bonded prior to bonding. This is accomplished by surface to surface vibration. Consequently, it has been found that the use of ultrasonic sealing in form/fill operations has distinct advantages. It produces consistent high strength seals.

Ultrasonic techniques have been used in bonding various materials. They have also been used in making bags and pouches. In US Patent 4,734,142 there is disclosed a bag sealing machine which utilises ultrasonic sealing. The bag that is produced would contain meat or produce. US Patent 4,767,492 discloses the use of ultrasonic techniques for sealing tubular containers. These containers are sealed in a separate operation after filling. In US Patent 4,866,914 there is disclosed an ultrasonic device for sealing pouches.

A product is placed into the pouch and the pouch subsequently ultrasonically sealed in another operation. It is noted in this patent that any foreign substances adhering to the sealing surfaces will be removed during the sealing operation. These patents illustrate the state of the art of ultrasonic sealing pouches. However, none of these patents is directed to the use of ultrasonic sealing in a form/fill process.

It is also known to use an ultrasonic horn and anvil to both seal and to cut a film. In US Patent 3,939,033 there is disclosed a process where the stationary fixture has a first raised means for sealing and a second raised means for cutting. That is, the same surface does not do the sealing and the cutting.

However, it has been found that the same surface can do both the sealing and the cutting. This results in a more efficient ultrasonic unit.

It has been found to be advantageous in forming and filling thermoplastic pouches to use ultrasonic sealing techniques in forming the pouches. Ultrasonic sealing has advantages over the use of adhesives, conduction heating or dielectric heating. A distinct advantage is the ability to simultaneously clean the surface of the film that is to be a part of the seal while heating this surface to at least its melting point. This is important in form/fill sequences where the pouch will be formed and filled in the same sequence. In such packaging operations, the substance being packaged, usually a liquid, will contaminate some of the seal area when it is flowed into the open pouch.

In order to get a good seal, this area should be clean.

This can be accomplished in various ways. However, the most efficient way is to use ultrasonic sealing techniques. In this way, the sealed area will be cleaned as it is being sealed.

Also a part of the present invention is the use of an ultrasonic sealing unit which is comprised of an ultrasonic horn and an anvil for the dual purpose of sealing a film and cutting a film. This is accomplished by the same surfaces on the ultrasonic horn and anvil. The shaped cutting surface will, preferably be a part of the anvil and will desirably be of a triangular cross-sectional shape. The outside base angles of the triangle will be about 1200 to 1600.

This will provide for 200 to 600 interior angles. The top.of the shape terminates in a smooth edge.

Further, the pouch containers which are sealed by ultrasonic welding can be severed one from the other using the ultrasonic sealing units to sever the film after sealing the film. This can be done by the energy director on the ultrasonic horn having sidewalls of a given angle and by increasing the pressure of the ultrasonic horn against the anvil.

In a first aspect the present invention is directed to a process for the ultrasonic sealing of pouch containers during the process of filling the pouches as well as the use of the ultrasonic horn and anvil assembly as a means for both sealing and cutting the thermoplastic film. In this regard, the ultrasonic horn and/or anvil must be of a particular shape in order to provide for the dual functions of sealing a thermoplastic film and then severing the thermoplastic film in the region of the seal.

In order to provide for both the ultrasonic sealing of thermoplastic film and the subsequent severing of the film at least one of the ultrasonic horn or the anvil will have to be shaped for the severing operation. It is possible to have both the ultrasonic horn and the anvil of the ultrasonic sealing unit shaped to effectuate severing. However, this is not necessary. Only the ultrasonic horn or the anvil needs to be shaped for cutting. In this regard, it is preferred to shape the anvil. This is the case since the shaped piece will have greater wear. It is preferred to have an accelerated wearing of the anvil rather than of the ultrasonic horn.

Thus, according to a first aspect of the present invention, a method of forming a shaped, sealed flexible film pouch containing a liquid substance comprises partially forming flexible film into a pouch using ultrasonic energy, substantially filling said partially formed pouch with the said liquid substance, closing the said pouch by sealing the opening through which the pouch has been filled using ultrasonic energy applied by an ultrasonic horn to an anvil at a first contact pressure, and increasing the contact pressure to sever the film.

Preferably the method comprises: (a) shaping a flexible film into a tubular shape with an overlapping edge; (b) contacting the overlapping edge of the said film in a tubular shape with ultrasonic energy to bond the overlapping edge of the said tubular shape to form a tube; (c) sealing by ultrasonic energy a lower portion of the said tube to form a first pouch; (d) filling the said first pouch with a substance; and (e) sealing by ultrasonic energy (I) an upper portion of the said first pouch to seal the said pouch, and (II) another portion, (upstream of the first pouch) of the said tube to form a second pouch, and severing the said first pouch from the said second pouch.

Preferably a die shapes the said film into a tubular shape having an overlap of about O.lcm to about 1.0 cm.

The said overlapping edge is preferably contacted with ultrasonic energy at a contact pressure of an ultrasonic horn and anvil of about 10 kg/cm2 to about 50 kg/cm2 and an ultrasonic energy of about 10 KHz o 70 KHz .

The said sealing of the said upper and lower portions and severing of one tube from another tube is preferably by means of contacting the said tube at a contact pressure of an ultrasonic horn and an anvil of about 10 kg/cm2 to about 70 kg/cm2 and an ultrasonic energy of about 10 KHz to 50 KHz and then increasing the contact pressure between the said ultrasonic horn and the said anvil to about 20 kg/cm2 to about 100 kg/cm2 to sever the film in the area of the seals that have been formed.

The said flexible film desirably has at least one ply that is bondable to itself by means of ultrasonic energy, e.g. the said flexible film preferably has at least one polyene layer and an ethylene-vinyl acetate layer. The said polyene layer may be selected from the group consisting of polyethylene, polypropylene, polybutylene and polybutadiene.

The said flexible film is preferably fed as a continuous sheet, formed into a continuous tubular shape and sealed to form a continuous tube.

The said flexible film is desirably in a stationary position when the said upper portion and lower portion are sealed and one pouch severed from another pouch.

In the sealing of the top seal to form a pouch and a beak spout adjacent to the top seal, the excess film in the area of the beak spout may be severed in a second step.

The invention in another aspect extends to a shaped sealed flexible film pouch containing a liquid substance, the pouch being comprised of one or more plies, having a side seam, a lower seam, an upper seam, and a spout, all sealed through the use of ultrasonic energy.

The said spout is preferably at the upper edge of the said pouch and preferably is in the form of a beak.

The invention further extends to an apparatus for forming and filling pouches comprising: (a) means to shape a flexible film into a tube having an overlapping longitudinal seam; (b) a first ultrasonic horn and anvil assembly; (c) means to position the overlapping longitudinal seam of the said flexible film between the said first ultrasonic horn and anvil; (d) means to actuate the said first ultrasonic horn and anvil assembly to seal the said overlapping seam to form a tube; (e) a second ultrasonic horn and anvil assembly located subsequent to the said first ultrasonic horn and anvil to form top and bottom closures on the said tube and produce a pouch;; (f) means to actuate the said second ultrasonic horn and anvil assembly at a first contact pressure to seal the said top and bottom closures and at a second contact pressure to sever the film that has been sealed to separate a filled pouch from the said tube; and (g) filling means adapted to substantially fill the said pouch subsequent to forming the said bottom closure and prior to forming the said top closure.

The apparatus preferably comprises means to produce a contact pressure between the said first ultrasonic horn and stationary fixture of about 10 kg/cm2 to 70 kg/cm2.

The said second ultrasonic horn and anvil assembly is preferably comprised of an anvil having a raised cutting surface.

The said raised cutting surface desirably has a base exterior angle of about 1200 to 1600.

The said second stationary fixture preferably has a surface adapted to cut a film after sealing.

The apparatus preferably comprises means to produce a pressure of about 10 kg/cm2 to 70 kg/cm2 between said second ultrasonic horn and anvil during sealing and a pressure of about 20 kg/cm2 to 100 kg/cm2 during severing.

The invention also extends to an ultrasonic horn and anvil assembly for sealing and severing thermoplastic film comprising a shaped contact surface on one of the said ultrasonic horn or anvil adapted to seal the said film upon the application of a first pressure and ultrasonic energy and to sever the said film upon the application of a second higher pressure.

The said shaped contact surface is preferably essentially triangular in cross-section with the base exterior angle being about 1200 to 1600.

The second aspect of the invention addresses a further problem and relates to a method and apparatus for filling packages, such as pouches, with liquids and preventing splashing of the filling substance. In particular, this aspect of the invention relates to a nozzle which includes means to prevent excess liquid from flowing into the pouch or bottle and means to maintain the exit of the nozzle above the level of the liquid in the pouch or bottle during filling, and the method of using this valve to fill pouches and bottles.

Many problems are met in the filling of pouch containers. One of these problems is the splashing of the liquid as it is being filled into the container.

Another problem is dripping from the nozzle after the container has been filled. Such splashing and dripping will result in contamination of the seal area of the container. Excessive splashing can also result in the container containing less than the stated amount of the liquid. When the container is a pouch, the problem is more the contamination of the seal area. This is the case since in many instances the pouch is being formed and filled in the same sequence. That is, the pouch is formed from a sheet of film, and when formed to a condition where it has a sealed bottom and sealed sides, it is filled. Then the top is sealed.

A problem can arise if the region that is to comprise the top seal has become coated with the substance being filled into the pouch container. This is caused by a turbulent flow splashing of the substance in the pouch during filling and dripping from the nozzle at the termination of filling. However, regardless of the exact cause of the coating of the interior surface with product, is known to be liable to deleterious to the subsequent formation of good seals.

It is therefore an object of this aspect of the invention to minimise this splashing and dripping from a nozzle after a filling cycle.

This aspect of the present invention is directed to a method and apparatus for filling container packages, and in particular for filling flexible film pouches. The apparatus consists of a nozzle which comprises an elongated tubular member having an aperture therethrough for the intermittent flow of a liquid. At the upper end, there is a means for the introduction of the liquid, and at the lower end, at least one screen means to induce a laminar flow and to decrease drip formation upon the cessation of the flow of the liquid. At the lower end in the region of one or more screens, there can be a suction means to remove excess liquid from the screen area.In addition, the entire elongated tubular member which comprises the nozzle can be moved upwardly as a container is being filled in order to maintain the exit end of the nozzle at a set distance above the level of the liquid in the container and thus minimise the impact energy of the liquid as it enters the package.

According to this aspect of the present invention an anti drip nozzle for filling containers e.g.

flexible film packages comprises an elongated tubular member having an aperture therethrough for the flow of a liquid, means at an upper end for the introduction of a liquid and an outlet aperture provided with at least one screen means across the aperture, and suction means adapted to remove liquid from the said screen, and preferably means adapted to cause the said tubular member to be raised during the filling of the container.

According to this aspect of the invention a method of filling a container e.g. a flexible film package or pouch with a liquid comprises (a) providing a tubular nozzle having a channel therethrough, means at one end of the said channel to attach the said valve to a source of a liquid, and suction means on the other end to prevent dripping upon the cessation of input of liquid to the said tubular nozzle; (b) as the container is being filled raising the tubular nozzle so as to maintain the said tubular nozzle above the surface of the liquid in the container; and (c) actuating the suction means upon the cessation of the flow of liquid to the said nozzle to remove excess liquid from the means to prevent dripping on the other end of the said tubular nozzle.

In the method, the nozzle is inserted into the pouch and the nozzle opened to flow liquid into the container. Liquid flows into the container and concurrently the nozzle moves upwardly so as to maintain the exit of the nozzle above the level of the liquid in the container during the filling sequence.

The nozzle is closed when the pouch is filled and the suction means is then actuated to remove any excess liquid from the region of the screen or screens to prevent drip formation. The nozzle is then ready for another filling sequence.

When a pouch is being filled, the nozzle will usually be a part of a form/fill sequence. When the pouch has been formed to a point where there are sealed bottom and sides, the pouch is in a condition for filling. At this point, the nozzle is near the bottom of the pouch. The nozzle is activated to flow a given amount of liquid into the pouch. Concurrently the nozzle is raised to maintain the nozzle above the level of the liquid flowing into the pouch. When the given amount of liquid has flowed into the pouch the flow ceases and by means of suction excess liquid in the region of the one or more screens of the nozzle is removed by means of the suction. This reduces drip formation upon the cessation of the flow of liquid.

As the container is being filled, the valve desirably moved upwardly so as to be a set distance above the level of the contents of the container during filling. In addition, the liquid passes through an anti-splash screen as it exits the valve. In a further feature, associated with the screen are one or more suction units which operate at the cessation of liquid flow from the valve to remove liquid from the screen and prevent dripping. The combination of the valve moving upwardly during container filling, a screen, and suction units associated with the screen function to prevent splashing during filling and dripping after filling.

The invention may be put into practice in various ways and one specific embodiment and a number of modifications will be described by way of example to illustrate the invention with reference to the accompanying drawings in which: Figure 1 is a rear elevational view of a pouch with a beak spout formed using ultrasonic techniques; Figure 2 is an elevational view of a sealing unit for sealing the longitudinal seam of the pouch of Figure 1; Figure 3 is a cross-sectional view of an anvil for sealing and severing a film; Figure 4 is a top plan view of the ultrasonic horn/anvil assembly for forming the top and bottom seals and beak spout of the pouch of Figure 1; Figure 5 is a cross-sectional view of the ultrasonic horn/anvil of Figure 4 along line 5-5; Figure 6 is an elevational view of the transverse ultrasonic horn and anvil assembly;; Figure 7 is an elevational view of the form/fill unit for forming and filling pouches; Figure 8 is an elevational view in section of another arrangement for filling the pouches namely a fill nozzle assembly in the closed position; Figure 9 is an elevational view in section of the fill nozzle assembly of Figure 8 in an open position; Figure 10 is a cross-sectional view of the fill nozzle assembly of Figure 8 along line 10-10; Figure 11 is an elevational view of the fill nozzle of Figure 8 at the start of the filling of a container; Figure 12 is an elevational view of the fill nozzle of Figure 8 with the container above half full, and Figure 13 is an elevational view of the fill nozzle of Figure 8 with the container having been filled.

The process of the first aspect of the invention will be described with reference to the manufacture of pouches having spouts, as shown in Figures 1 to 7. An illustrative pouch is set forth in Figure 1. This pouch is designated 10 and has a rear surface, 11, a longitudinal seal 12, a bottom seal 13 and a top seal 14. There is also a beak spout 15 with a cut-out 17 and an associated seal 16.

In the process of forming and filling the pouches of Figure 1, a film is in a first step formed into a tube which is accomplished by each edge of the film being overlapped from about 0.1 to 1.0 cm to form a seam. This seam is passed between the ultrasonic horn and an anvil of a longitudinal ultrasonic sealing unit.

Since the seam is now between the ultrasonic horn and the anvil upon the application of pressure and ultrasonic energy to the ultrasonic horn and/or anvil the thermoplastic material at the seam juncture is heated and bonded. Pressure is preferably applied to the ultrasonic horn. After this step, the film is now in the shape of a tube. Preferably, at the same time that the side seam is being sealed, a pouch top seam is being formed and sealed on a lower pouch. Also preferably at this time the beak spout is being formed on this lower pouch and a bottom seal on yet a further lower pouch. This is the case since the film is in a stationary position and for increased efficiency more than one operation can be conducted on the film at this time. Thus a side seal, a top and beak seal and a bottom seal can all be made at once, although on different pouches.This top and beak spout seam are formed by means of a separate transverse ultrasonic sealing unit vis-a-vis the side seal unit. This lower transverse ultrasonic sealing unit, will in a first step, place the interior surfaces of the tube into contact to form both the top closure seam and the beak spout seam, and thence through the application of pressure and ultrasonic energy will cause this pouch top seam to be bonded and the beak spout to be formed by bonding the surfaces to this shape. This film is now in the form of an inverted pouch which is open at its upper end. At this point, it -is now ready to be filled with a substance, usually a liquid. After filling, this filled pouch moves downwardly and the transverse ultrasonic sealing unit is activated for another cycle. The pouch bottom seal is formed on this filled pouch in this next cycle.Simultaneously the top seal is formed on the adjacent lower pouch along with a seal to form the beak spout. In each cycle after these seals are formed, the application of ultrasonic energy ceases and the pressure of the anvil against the ultrasonic horn is increased. In this way, the anvil and ultrasonic horn then function as a severing device to sever the film to form the beak spout on an upper pouch and to sever the now sealed and filled lower pouch from the upper pouch which has the top seal formed but has not as yet been filled.

In summary, the transverse ultrasonic energy sealing unit, at the same time as sealing the bottom seam of a filled lower tubular pouch will also seal the top seam of an upper pouch and form the beak spout of this upper pouch. This step can be carried out concurrently with other sealing steps since the film is in a stationary position. In this way, in this form/fill sequence, three different sealing operations can be conducted during each interval when there is a pause in the movement of the film. The side seam is sealed to form a tube, the top seal and spout are made for a pouch for which the side seam has previously been made, and the bottom closure seal is made on another pouch which has just been filed with a substance.

After the top seal and beak spout of the upper pouch and the bottom seal of the lower pouch have been formed, the ultrasonic energy is stopped and the pressure between the anvil and the ultrasonic horn is increased to thereby sever the lower filled pouch from the upper empty pouch. The lower filled pouch is then forwarded for packing and the upper formed pouch is filled. Also in the above sequence as the transverse seals are being formed, the beak spout is being formed.

A persistent problem with regard to these pouch containers is that of the contamination of the transverse sealing areas at the time that the pouch is being filled. This is a contamination by the contents that are being flowed into the pouch. This is caused by a splashing of the substance being flowed into the pouch and a dripping of the product upon the termination of the filling process. Since the inner thermoplastic surfaces are to be bonded, one to the other, excessive contamination can affect the integrity of the transverse seals. However, since in ultrasonic sealing it is the film juncture that is being heated, rather than the full thickness of the thermoplastic film, there is a more effective weld sealing of the pouches using ultrasonic sealing rather than other techniques.This is the case since the ultrasonic energy is focused on the inner juncture surfaces of the thermoplastic film and will quite efficiently remove any contaminating substances from these surfaces prior to seal formation. This is in contrast to radio frequency heating, also known as dielectric heating, where the full thickness of the thermoplastic film is heated. In dielectric heating there is not a concentration of the bonding energy only onto the thermoplastic junction surfaces. It is also not an energy which assists in the cleaning of the bonding surfaces.

The longitudinal sealing unit is shown in Figure 2. The ultrasonic horn 20 and the anvil 21 can each have a flat working surface. The surfaces will either both be smooth, or one surface can be textured and the other smooth. In use, the surface 22 of the ultrasonic horn is in close proximity to the surface 23 of the anvil. The anvil can optionally be cooled by flowing water of other fluid through each unit. If necessary the ultrasonic horn can be cooled by a jet of air. In the present instance, each of the ultrasonic horn and the stationary fixture are designed to be cooled. In this regard, the anvil has an inlet port 27 and an exit port 28 for the flow of a cooling fluid.Although any of the usual frequencies that are used for ultrasonic sealing can be used, it is preferred to use a frequency of about lOKHz (kilohertz) to 70 KHz and most preferably about 20 KHz to 40 KHz. Energy is supplied to the ultrasonic horn through a booster 29.

The longitudinal sealing unit is designed for sealing and need not be capable of also cutting film.

However, when it is desired that this unit also be used for cutting, the anvil of the ultrasonic horn would have a contact surface as shown in cross section in Figure 3. The angle A of the surface 30 is from about 1200 to 1600, and preferably about 1500 to 1750. This results broadly in an interior angle of 200 to 600.

The top surface 23(a) is an edge and is sufficient to produce an effective seal, but yet as the pressure between the ultrasonic horn and the anvil is increased, the film can be cut.

In Figure 4, there is shown the anvil assembly for producing the top and bottom seals and the beak spout for the pouch of Figure 1. This unit simultaneously forms the bottom seal of a lower pouch and the top seal and the seals around the beak spout of an adjacent upper pouch. After these seals are formed, the pressure between the ultrasonic horn and the anvil is increased, and the thermoplastic material between the bottom seal of one pouch and the top seal of another pouch and the excess material in the area of the beak spout is severed. This ultrasonic sealing unit must have sufficient energy to complete the seal and to thin the material for subsequent severing of the thermoplastic film.

The shape of the surfaces also produces a thinning of the film. An ultrasonic frequency of 10 KHz to 70 KHz is preferred, with a frequency of about 20 KHz to 40 KHz being most preferred.

The unit shown in Figure 4 is the anvil assembly 40 of the transverse ultrasonic sealing unit. This unit consists of base support plate surface 41 which supports the top and bottom sealing anvil 42 and the beak spout sealing anvil 43. Each of these anvils is raised above the surface of the support plate to the same extent. The sealing anvil 42 has a surface 44 which contacts the corresponding ultrasonic horn surface and the anvil 43 has a surface 45 which contacts the corresponding ultrasonic horn surface.

The base plate can be cooled by a fluid flowing through the plate via ports 46 and 47.

The contact surfaces 44 and 45 are in the form of an edge and are effective to produce the desired seal and subsequently to cut the film. Consistent with the desired seal this surface will preferably be an edge desirably a dull edge. The shape of the anvils of this ultrasonic sealing unit is shown in more detail in Figure 5. The exterior angle A of the anvil with the horizontal axis, which in Figure 5 is also the base plate, is about 1200 to 1600, and preferably about 135C to 1500. This results in interior angles of about 20C to 600 and preferably about 700 to 450. The anvils are shaped to produce effective sealing and effective severing of the film after sealing. During the sealing operation, the pressure between the anvil and ultrasonic horn, is about 10 kg/cm2 to 50 kg/cm2.This is increased to about 20 kg/cm2 to 100 kg/cm2 for severing the film. The increased pressure is dependent on the pressure that is utilised during the sealing operations. The pressure can be increased by the anvil being moved against the ultrasonic horn or the ultrasonic horn being moved against the anvil.

In Figure 6 there is shown the complete transverse ultrasonic sealing unit for forming the top and bottom pouch seals and the beak spout seals. This consists of essentially the anvil assembly 40 and the ultrasonic horn 35. This unit produces the top and bottom seals as well as the beak spout seals. This ultrasonic horn consists of flat surfaces 36 to contact the shaped surfaces 44 and 45 of the anvil. The ultrasonic energy is transferred from the booster 37 to the horn.

However as noted above, the ultrasonic horn can be shaped to function to sever the film rather than the anvil being shaped to serve its purpose. Either the ultrasonic horn or anvil must be shaped to provide for a severing of the film after sealing. If the ultrasonic horn is to function to sever the film, the contact portion 36 of the ultrasonic horn must be of the shape as is illustrated for the anvil. In such an instance the anvil will have a flat surface.

As the pressure is increased on the film after the film has been sealed the film will flow due to the exerted pressure. This causes the film to sever at a mid-point of the seal. Neither the horn nor anvil has a sharp cutting surface rather they have dull edges.

The seal extends a very short distance beyond the horn and anvil profile. The horn and anvil together both seal and sever the film.

The ultrasonic horns can be constructed of titanium, Monel alloys, aluminium or aluminium alloys.

Titanium is an effective metal for ultrasonic horns.

The anvil can be of the same or a different metal from that of the ultrasonic horn. The anvil can also be a stainless steel. The anvil should have a low wear rate.

Figure 7 sets out a first embodiment of a form/fill apparatus in accordance with the invention.

In this form/fill apparatus the pouch of Figure 1 is formed and filled in a top side down arrangement. That is, the beak spout and top seal are formed first in the lower portion of the tube, the partially formed pouch filled, and the bottom seal then formed. This arrangement is needed for the formation of a pouch with a beak seal since the pouch must be filled after the beak is formed. The apparatus of figure 7 is a form/fill apparatus. In this regard, it both forms and fills the pouches. The pouches are formed from a continuous sheet of plastic film. The film is shaped into a continuousLat 51 with the side seam sealed at 60. Below 60, the film is in the form of a continuous tubing. Between 65 and 67 the tubing is filled with a liquid. The filling tube 59 that is shown is stationary. At 67 there is a sealing/severing unit of Figure 4.When this unit operates, edge 44 will seal and sever one pouch from another while edge 45 will produce a beak spout. In operation the tubing in the region between 65 and 67 is sealed at the bottom and a beak spout formed. It is then filled. In the next step, the filled pouch moves downward and stops. It is then sealed at what will be the bottom edge and severed from the upper pouch which had a pouch top seal and beak formed. The upper pouch is then filled. The sequence is then repeated. The pouches are filled from what is ultimately the lower end of the sequence.

Three pouches 68 are shown as being conveyed for packaging. Two different pouches are being operated on at 67 at one time. The upper pouch where the beak and pouch top seal 14 is being formed, and the lower pouch where the pouch bottom seal 13 is being formed.

In more detail the film 51 is unwound from a supply roll 50. This passes down over a tension roller 52 and over directional rollers 53 and 54. The film then passes over a roller 56 and downward to the form/fill section. At 57, the film is formed into an open tubular shape. Shaper 57 is supported by a fill conduit 59 which receives a product to be packaged, usually a liquid product from a supply conduit 58. The fill conduit 59 is stationary and does not move (in a modification described below in

8 to 13 the filling assembly moves so as to reduce any tendency to splashing of the pouch surfaces before sealing). The film passes in an open fashion by the supply conduit 58 to the seam forming and longitudinal sealing section 60. In this sealing section, a guide 61 directs the film into a shape so that there is an overlapping longitudinal seam for sealing by the longitudinal ultrasonic sealing unit. The longitudinal ultrasonic horn 63 receives ultrasonic energy from a transducer 62. The anvil is carried by the fill conduit 59. The film, now in a tubular form, emerges from the longitudinal sealing section 60 and is moved downwardly by a controller 64. The controller 64 moves the film intermittently and stops movement of the film in order to permit the sealing, cutting and filling operations.

This controller controls drive rollers 65 which move the film.

In the region below the controller, the tube is transversely sealed at 67. This is accomplished by the lower sealing unit as illustrated in Figures 4, 5 and 6. This lower sealing unit will form the top seal and the beak spout on the tube to form an open ended pouch.

This pouch is in an inverted arrangement.

Simultaneously, a lower pouch that has been filled receives a bottom seal. This all occurs at a first pressure between the ultrasonic horn and the anvil and the application of ultrasonic energy. At a second higher pressure of the ultrasonic horn against the anvil, and without the application of ultrasonic energy, the film is cut to separate the lower pouch and to cut the film to form the beak spout on the upper pouch. In this sequence, after the top seal and beak spout are formed, a pouch is filled from the spout 66 of the fill tube 59. After the filling step,the filled pouch moves downwardly and the transverse ultrasonic sealing unit goes through another cycle of making the bottom seal of this pouch and the top seal and beak of another pouch.

As has been noted, the flow of the film is intermittent. The flow of film is stopped for the sealing operations and for pouch filling. Thus, each time that the film flow stops, the longitudinal ultrasonic sealing unit 63 is actuated as is the transverse ultrasonic sealing unit 67. Also, while the movement of the film (film flow) has stopped, the pouch that has been formed is filled.

A preferred embodiment of filling conduit will now be described with reference to Figures 8 to 13 as mentioned above.

Figure 8, the fill nozzle 110 is shown in a closed position. In this position, no liquid can exit through the opening 123 of the nozzle 110. The nozzle consists of a body 114 which receives liquid through a channel 112 of a conduit 111. Liquid is received from a conduit 136 through an opening 135. This conduit 111 also supports the nozzle and provides the means for raising and lowering the nozzle during container filling cycles. The conduit 111 threadedly engages the nozzle body 114 by means of a thread 113. The conduit 115 in the nozzle body permits liquid to flow into the valve stem housing 116 and to the area of the valve seat 117 of the nozzle. The liquid passes around the valve stem guide 126 of the valve stem 118 to the region of the valve seat 117. The lower part of the valve stem contacts the valve seat when the valve is in the closed position.This will stop the flow of liquid. When in an open position as shown in Figure 9, the conduit 115 will communicate with the chamber 121 with liquid flowing from the conduit 115 into the chamber 121. At the lower part of the chamber 121, there are one or more screens 122 adapted to induce laminar flow in the liquid that is being flowed. After flowing through the screen the liquid will exit from the nozzle through the aperture 123. Communicating with the chamber 121 are one or more conduits 120 which serve to remove any excess liquid from the chamber 121 after the flow of liquid from the conduit 115 to the chamber 121 ceases. This liquid is removed by means of a suction drawn on the conduits 120.

The nozzle 110 is preferably an electromechanical device, but it could be a mechanical device. As an electromechanical nozzle, a magnetic field induced in the coils 125 causes the magnet 127 to move upwardly.

The magnet is an integral part of the valve stem guide 126. Stops 128 as well as the seat 118 will limit the movement of the stem 117.

Figure 9 shows the nozzle in an open position.

The valve stem is in a downward position thus permitting liquid to flow through the conduit 115 to the chamber 121. The liquid will flow through the screen 122 and exit via the aperture 123. When the nozzle again closes, a suction is drawn on the conduits 120 in order to remove excess liquid from the chamber 121.

Figure 10 shows a cross-section of the nozzle along the line 10-10 of Figure 8. Here there is shown the nozzle body 114, the chamber 121, the valve stem 117 and the suction conduits 120.

Figures 11 to 13 show the nozzle filling a container. In Figure 11, the nozzle 110 is shown to be fully within the container 130 and filling the liquid 131 into the container. The liquid flows from the nozzle 110 in an essentially laminar flow. This is the result of having passed through the screen. In Figure 12, the container 130 is shown to be about half full of liquid. In this view, the nozzle 110 has moved upwardly to keep the aperture 123 of the nozzle just above the level of the liquid 131 in the container. In Figure 13, the container 130 is shown to be full. The nozzle is located above the level of the liquid and the flow of liquid from the nozzle has ceased. At this point, a suction is drawn on the conduits 120 so as to remove excess liquid from the lower part of the nozzle, ie, from the region of the screen or screens.

The primary functions of the screen or screens 122 are to impart a laminar flow to the liquid emerging from the nozzle and to aid in preventing drip from the nozzle when it is in a closed position. This screen can be a single screen or a plurality of stacked screens. It is preferred that a single screen be used and that it have a thickness of about 0.1 mm (millimetres) to 10 mm and preferably about 0.2 mm to 5 mm. The screen will have a mesh opening of about 0.1 to 5 mm, and preferably about 0.5 to 2.5 mm. This will be sufficient to produce channels through which the liquid will flow thus inducing an essentially laminar flow.

It is also preferred that the nozzle be of a diameter to essentially fill the cross-section of the container during filling. For a pouch, this will be about 60 to 90 per cent of the diameter of the container. When the container is a jar, this will be about 60 to 90 per cent of the neck opening of the jar.

A large diameter nozzle will produce less splashing since the liquid will flow at a lower velocity. In addition, the risk of highly turbulent flow is minimised. In this way splashing and the contamination of the inner walls of the container is reduced.

The nozzle 110 is moved upwardly and downwardly either mechanically, hydraulically or pneumatically.

In hydraulic or pneumatic actuation, there will be a piston directly or indirectly affixed to the conduit 111. A liquid or a gas acting on this piston will raise and lower the nozzle 110. In a mechanical operation, the conduit 111 can have a gear such as a rack gear as a part of its exterior surface. Then a gear meshing with this rack will raise and lower the nozzle. Other mechanical arrangements can also be used. In Figure 8, there is shown an hydraulic or pneumatic technique for raising and lowering the nozzle 110. There is shown here a bar 137 which is connected to a piston rod 138 of a piston 139 which moves in a cylinder 140. The cylinder 140 is braced on a support 141. A fluid or a gas is pumped into the aperture 42' or the aperture 42" in order to move the piston and thus the valve 110. A mechanical technique is shown in Figure 9. Here the gear rack 143 is rigidly attached to the conduit 111. The rotation of the gear 144 causes the nozzle 110 to move upwardly and downwardly.

In filling a film pouch, the nozzle is moved downwardly to near the bottom of the pouch and liquid flow into the pouch is initiated. As the liquid flows into the pouch, the nozzle is moved upwardly in order to maintain the bottom of the nozzle above the level of the liquid in the pouch. When the given amount of liquid has been flowed into the pouch, the flow of liquid is terminated and a suction is drawn on the bottom portion of the valve in order to prevent drip formation. Excess liquid is drawn from the area of the one or more screens of the nozzle into a recycle tank.

The suction is then terminated and nozzle is ready to be lowered and another cycle commenced.

A prime objective of this filling nozzle is to prevent the liquid that is being filled into pouches and other containers from splashing up around the fill nozzle and wetting the film in the area where a seal will have to be made in a subsequent step. If the area that is to comprise the seal has been wetted with product, there is the potential for a weaker seal being formed.

Essentially any film which can be welded by means of ultrasonic energy can be utilised to form the present pouches. The particular thermoplastic films can be either amorphous or crystalline. Suitable films include those of acrylic copolymers, cellulosic, phenylene oxide, polycarbonate, and polystyrene.

Generally, crystalline resins are not as easily sealed using ultrasonic techniques as amorphous resins.

Crystalline films are more rigid. Flexible films are preferred. However, acetal resins, fluoropolymer resins, nylon resins and polyester resins can be utilised in ultrasonic sealing techniques. A preferred film is one which contains at least one layer of ethylene-vinyl acetate. The other layer or layers can be polyolefin such as polyethylene, polypropylene, polybutylene or polybutadiene.

The pouches which can be formed using the present ultrasonic sealing techniques can be of essentially any size. However, the preferred sizes range from about 50cc. to about 2 litres in size. These are the sizes that are conveniently handled with regard to this type of packaging technique. The substances which are packaged within such pouches include personal care products, household care products and foods. In the category of personal care products, there are liquid soaps, shampoos, and lotions. In the household care area, there are cleaning and polishing compositions, fabric bleach compositions, and general purpose soap compositions. In the food area, there are included various sauces, gravies, fruit flavourings and the like.

EXAMPLE 1 This example illustrates the forming and filling of pouches using the form/fill apparatus of Figure 7.

A polyethylene/ethylene-vinyl acetate coextruded film 51 having a thickness of 0.20 mm and a width of 16 cm is fed from the supply roll 50 to a pouch forming and filling machine via rollers 52, 53, 54 and 56. The film is fed in a continuous strand 51 to a form/fill machine. As the film passes through an upper shaper die 57, it is formed into a tubular shape with an overlapping longitudinal seam. The film overlaps by about 10 mm. The film passes between a longitudinal ultrasonic horn 63 and a stationary fixture. The impinging pressure is about 40kg/sq. cm. The movement of the film ceases momentarily during this operation.

The side seam is formed by the film edges being held between the longitudinal ultrasonic horn and the anvil (as shown in Figure 2) and ultrasonic energy at a frequency of 20 KHz applied. At the same time, transverse bottom seals are being formed at the lower portion of the tube as is a beak spout. This is formed by a transverse ultrasonic horn and mobile anvil assembly 67 (as shown in Figures 4 to 6). At the same time that the top seal and beak spout are formed on this pouch, a bottom seal is being formed in a lower pouch which has been filled. An ultrasonic frequency of 35 KHz is used to form these seals. The impinging pressure of the transverse ultrasonic horn and anvil assembly during sealing is about 40kg/sq cm.After the side and top seals along with beak spout are formed on the present pouch, the thus newly formed pouch with an open bottom (at its top end) is filled with 250 cc of bleach. The lower pouch 68, which has undergone closure sealing, has been severed and is conveyed to packing. The severing is accomplished by increasing the impinging pressure of the ultrasonic horn against the stationary fixture to about 90 kg/sq cm. No ultrasonic energy is applied at this time. This then completes a machine cycle. This cycle is then repeated.

The sealed seams of a representative number of pouches are tested in a pressure tester. The pressure tester has a stationary and a movable platen. A sample is placed between the platens and the pressure on the pouch increased. A burst strength of greater than 150 kg indicates an acceptably filled pouch. The pouches consistently exceed 150 kg.

EXAMPLE 2 The apparatus of Figures 1 to 7 is used in combination with the apparatus of Figures 8 to 13 so that the stationary fill tube 59 of Figure 7 is replaced by the moving fill tube arrangement of nozzle 110 etc. of Figures 8 to 13.

Claims

1. A method of forming a shaped, sealed flexible film pouch containing a liquid substance comprising partially forming flexible film into a pouch using ultrasonic energy, substantially filling said partially formed pouch with the said liquid substance, closing the said pouch by sealing the opening through which the pouch has been filled using ultrasonic energy applied by an ultrasonic horn to an anvil at a first contact pressure, and increasing the contact pressure to sever the film.

2. A method as claimed in Claim 1 comprising: (a) shaping a flexible film into a tubular shape with an overlapping edge; (b) contacting the overlapping edge of the said film in a tubular shape with ultrasonic energy to bond the overlapping edge of the said tubular shape to form a tube; (c) sealing by ultrasonic energy a lower portion of the said tube to form a first pouch; (d) filling the said first pouch with a substance; and (e) sealing by ultrasonic energy (I) an upper portion of the said first pouch to seal the said pouch, and (II) another portion of the said tube to form a second pouch, and severing the said first pouch from the said second pouch.

3. A method as claimed in Claim 1 or Claim 2 in which a die shapes the said film into a tubular shape having an overlap of about 0.1cm to about 1.0 cm.

4. A method as claimed in Claim 1, 2 or 3 in which the said overlapping edge is contacted with ultrasonic energy at a contact pressure of an ultrasonic horn and anvil of about 10 kg/cm2 to about 50 kg/cm2 and an ultrasonic energy of about 10 KHz o 70 KHz .

5. A method as claimed in any one of Claims 1 to 4 in which the said sealing of the said upper and lower portions and severing of one tube from another tube is by means of contacting the said tube at a contact pressure of an ultrasonic horn and an anvil of about 10 kg/cm2 to about 70 kg/cm2 and an ultrasonic energy of about 10 KHz to 50 KHz and then increasing the contact pressure between the said ultrasonic horn and the said anvil to about 20 kg/cm2 to about 100 kg/cm2 to sever the film in the area of the seals that have been formed.

6. A method as claimed in any one of Claims 1 to 5 in which the said flexible film has at least one ply that is bondable to itself by means of ultrasonic energy.

7. A method as claimed in Claim 6 in which the said flexible film has at least one polyene layer and an ethylene-vinyl acetate layer.

8. A method as claimed in Claim 7 in which the said polyene layer is selected from the group consisting of polyethylene, polypropylene, polybutylene and polybutadiene.

9. A method as claimed in any one of Claims 1 to 8 in which the said flexible film is fed as a continuous sheet, formed into a continuous tubular shape and sealed to form a continuous tube.

10. A method as claimed in any one of Claims 1 to 9 in which the said flexible film is in a stationary position when the said upper portion and lower portion are sealed and one pouch severed from another pouch.

11. A method as claimed in any one of Claims 1 to 10 in which, in the sealing of the top seal to form a pouch and a beak spout adjacent to the top seal, the excess film in the area of the beak spout is severed in a second step.

12. A method as claimed in Claim 1 substantially as specifically described herein with reference to the accompanying examples and drawings.

13. A shaped sealed flexible film pouch containing a liquid substance comprised of one or more plies, having a side seam, a lower seam, an upper seam, and a spout, all sealed through the use of ultrasonic energy.

14. A shaped sealed flexible film pouch as claimed in Claim 13 in which the said spout is at the upper edge of the said pouch and is in the form of a beak.

15. A pouch as claimed in Claim 13 substantially as specifically described herein with reference to the examples and Figure 1 of the accompanying drawings.

16. An apparatus for forming and filling pouches comprising: (a) means to shape a flexible film into a tube having an overlapping longitudinal seam; (b) a first ultrasonic horn and anvil assembly; (c) means to position the overlapping longitudinal seam of the said flexible film between the said first ultrasonic horn and anvil; (d) means to actuate the said first ultrasonic horn and anvil assembly to seal the said overlapping seam to form a tube; (e) a second ultrasonic horn and anvil assembly located subsequent to the said first ultrasonic.horn and anvil to form top and bottom closures on the said tube and produce a pouch;; (f) means to actuate the said second ultrasonic horn and anvil assembly at a first contact pressure to seal the said top and bottom closures and at a second contact pressure to sever the film that has been sealed to separate a filled pouch from the said tube; and (g) filling means adapted to substantially fill the said pouch subsequent to forming the said bottom closure and prior to forming the said top closure.

17. An apparatus as claimed in Claim 16 comprising means to produce a contact pressure between the said first ultrasonic horn and stationary fixture of about 10 kg/cm2 to 70 kg/cm2.

18. An apparatus as claimed in Claim 16 or Claim 17 in which the said second ultrasonic horn and anvil assembly is comprised of an anvil having a raised cutting surface.

19. An apparatus as claimed in Claim 18 in which the said raised cutting surface has a base exterior angle of about 1200 to 1600.

20. An apparatus as claimed in Claim 16, 17, 18 or 19 in which the said second stationary fixture has a surface adapted to cut a film after sealing.

21. An apparatus as claimed in any one of Claims 16 to 20 comprising means to produce a pressure of about 10 kg/cm2 to 70 kg/cm2 between said second ultrasonic horn and anvil during sealing and a pressure of about 20 kg/cm2 to 100 kg/cm2 during severing.

22. Apparatus as claimed in Claim 16 substantially as specifically described herein with reference to Figures 2 to 7.

23. An ultrasonic horn and anvil assembly for sealing and severing thermoplastic film comprising a shaped contact surface on one of the said ultrasonic horn or anvil adapted to seal the said film upon the application of a first pressure and ultrasonic energy and to sever the said film upon the application of a second higher pressure.

24. An ultrasonic horn and anvil assembly as claimed in Claim 20 in which the said shaped contact surface is essentially triangular in cross-section with the base exterior angle being about 1200 to 1600.

25. An ultrasonic horn and anvil assembly as claimed in Claim 23 substantially as specifically described herein with reference to Figures 2 and 3 or 4, 5 and 6 of the accompanying drawings.

26. Apparatus as claimed in any one of Claims 16 to 22 in which the filling means incorporate an anti-drip nozzle comprising an elongated tubular member having an aperture therethrough for the flow of a liquid, means at an upper end for the introduction of a liquid and an outlet aperture provided with at least one screen means across the aperture, and suction means adapted to remove liquid from the said screen, and means adapted to cause the said tubular member to be raised during the filling of the container.

27. Apparatus as claimed in Claim 26 in which the screen means are such as to induce laminar flow and to decrease drip formation upon cessation of flow of the said liquid.

28. Apparatus as claimed in Claim 26 or Claim 27 in which the suction means are located in the region adjacent to the said screen to remove excess liquid from the said screen.

29. Apparatus as claimed in any one of Claims 26 to 28 comprising means to maintain the outlet aperture of the said tubular member above the level of the said liquid while the said flexible film package is being filled.

30. Apparatus as claimed in any one of Claims 16 to 22 in which the filling means incorporate an anti-drip nozzle comprising an elongated tubular member having an aperture therethrough for the flow of a liquid, means at the upper end for the introduction of a liquid and at least one screen means at the other end to induce laminar flow and to decrease drip formation upon the cessation of flow of the said liquid, suction means for removing liquid from the said screens and means to maintain the exit of said tubular member above the said liquid while the said flexible film package is being filled.

31. Apparatus as claimed in any one of Claims 26 to 30 in which there are a plurality of screens.

32. Apparatus as claimed in any one of Claims 26 to 31 in which the said screens have a thickness of about 0.1 to 10 cm, e.g. 0.1 to 10 mm.

33. Apparatus as claimed in any one of Claims 26 to 32 in which there are a plurality of suction means to remove excess liquid from the said screen.

34. Apparatus as claimed in any one of Claims 26 to 33 in which the body of the said valve substantially fills the cross-section of the flexible film package or the neck of the container which is being filled.

35. Apparatus as claimed in Claim 30 or any one of Claims 31 to 34 when dependent on Claim 30 in which there is at least one suction means in the region adjacent to the said screen to remove excess liquid from the said screen.

36. A method as claimed in any one of Claims 1 to 12 further comprising: (a) providing a tubular nozzle having a channel therethrough, means at one end of the said channel to attach the said valve to a source of a liquid, and suction means on the other end to prevent dripping upon the cessation of input of liquid to the said tubular nozzle; (b) as the container is being filled raising the tubular nozzle so as to maintain the said tubular nozzle above the surface of the liquid in the container; and (c) actuating the suction means upon the cessation of the flow of liquid to the said nozzle to remove excess liquid from the means to prevent dripping on the other end of the said tubular nozzle.

37. A method as claimed in any one of Claims 1 to 12 further comprising (a) providing an elongated tubular nozzle having a channel therethrough for the delivery of liquid to a container including a plurality of screens and suction means adjacent to the said screens; (b) moving the said nozzle into the container, which is to be filled, adjacent to the bottom of the said container; (c) flowing a liquid through the said nozzle and moving the exit end of the said nozzle to maintain the said nozzle exit end above the level of the liquid in the container; (d) ceasing the flow of liquid from the said nozzle; and (e) activating the said suction means to remove liquid from the region of the said screens.

38. A method as claimed in Claim 36 or Claim 37 in which the liquid removed by the said suction means is flowed to a recycle tank.

39. A method as claimed in Claims 36, 37 or 38 in which the said liquid is selected from the group consisting of detergent, bleach, fabric softener and lotions.