Patent Application
20050260090
The present invention relates to a pump which can be easily made and assembled from a small number of moulded parts, particularly from injection moulded parts. The invention further relates to a dispenser comprising the pump and to valving arrangements for pumps and dispensers. The pump and device are useful for dispensing fluids such as medicines, including nasal and throat sprays, perfumes, cosmetics, cleaning products and the like.
The delivery of substances from a dispenser, particularly in carefully controlled amounts, generally requires a pump of some sort typically with one or more valves associated with it. The provision of such pumps not only adds to the cost and complexity of manufacturing dispensers, since typical pumps comprise many separate parts, but can also restrict their overall design. Efforts have been made to reduce the complexity of pumps. WO 98/08661 discloses a readily manufactured pump having a small number of stackable parts. However, it still requires four parts which need to be separately manufactured and assembled. WO 02/16047 discloses another simple diaphragm pump, incorporated into the inside of a dispensing flexible reservoir; it too comprises four parts.
U.S. Pat. No. 6,460,781, U.S. 2003/0071071, U.S. 2002/0190081 and WO 00/06464 all describe simple product dispensers, suitable as sampling devices which comprise a reservoir and a resilient means which is deformable in order to produce a pumping action from the reservoir.
U.S. Pat. No. 5,492,252, EP 641 722 and EP 442 858 each describe dispensers incorporating pumps which utilise a resilient actuator as an insert into a pre-moulded pump chamber comprising an inlet port.
Despite all the foregoing there remains a need for further improvements in product dispensers to enable simple, low cost manufacture of product dispensers incorporating pumps, in particular those which are capable of reliably delivering repeated controlled product doses. A related problem is that of enabling a simple method of modular construction of dispensers whereby differently functioning pumps, e.g. delivering different size doses, can be fitted to a common dispenser, enabling a flexible method of adapting a production line to provide different products.
A pump of simple construction has now been developed which can be manufactured from as few as two separate parts and, in particular, each part can be formed by mass production techniques such as injection moulding, compression moulding or thermoforming. The pump can be employed as a separate part in a more complex dispenser or indeed can be integrally moulded into a simple dispenser. The construction of the pump provides for much greater design freedom in the way that the pump is employed in dispensers and, as a result, in the dispenser design.
The invention herein relates to pumps and valving arrangements for fluid dispensers. The invention further relates to dispensers incorporating a pump. The pumps herein comprise a dose chamber, a resilient actuator and valves for controlling the flow of fluid into and out of the dose chamber. Combination of the pump with a fluid reservoir provides a fluid dispenser which may further comprise an atomiser for forming a spray as fluid is ejected from a dispenser outlet.
In accordance with a first aspect of this invention there is provided a pump for a fluid dispenser comprising:
In accordance with a second aspect of this invention there is provided a method of making a pump for a fluid dispenser, the pump comprising an upper pump half comprising a semirigid, thermoplastic material, a lower pump half, a dose chamber, a resilient actuator, a pump inlet port, a pump outlet port, an inlet valve and an outlet valve, the method comprising the steps of:
In accordance with a third aspect of this invention there is provided a method of making a pump for a fluid dispenser, the pump comprising an upper pump half comprising a semirigid, thermoplastic material, a lower pump half, a dose chamber, a resilient actuator, a pump inlet port, a pump outlet port, an inlet valve and an outlet valve, the method comprising the steps of:
In accordance with a fourth aspect of this invention there is provided a valve module for a pump for a fluid dispenser comprising:
In accordance with a fifth aspect of this invention there is provided a valving arrangement, suitable for use in a pump dispenser, comprising a flow channel having semirigid upper and lower walls, a fluid inlet through which fluid enters the arrangement from a fluid supply and a fluid outlet through which the fluid exits the valving arrangement, the flow channel further comprising inlet and outlet elastomeric, flap valves, mounted inside the flow channel, each valve having a surface immovably fixed to the upper flow channel wall and a flap sealingly compressed against the lower flow channel wall, whereby each valve prevents flow of fluid along the flow channel until a positive fluid pressure differential on an upstream side of the flap of the valve causes the flap to lift thereby allowing fluid to flow past the valve, the valves permitting fluid flow in the same direction along the flow channel whereby an increase in fluid pressure in a section of flow channel between the two valves causes the outlet valve to open and the inlet valve to remain closed and a reduction in fluid pressure in the section of flow channel between the two valves causes the inlet valve to open and the outlet valve to remain closed.
In preferred embodiments of the invention the pump is incorporated into a dispenser further comprising a fluid reservoir in fluid communication with the pump inlet port. Preferably the reservoir is co-moulded with the pump.
The resilient actuator of the pumps preferably has a threshold force for actuation which facilitates consistent unit dosing. The pumps, valving arrangements, dispensers and actuators herein are amenable to a modular approach to construction which provides substantial flexibility in a mass manufacturing environment.
The invention will now be described in more detail with reference to component parts of the pumps, valve modules and dispensers herein, first in general terms and then with reference to specific embodiments.
Definitions
The pumps and dispensers comprise upper and lower halves. The terms “half” and “halves” herein are intended only to indicate corresponding parts and are not intended to imply any equality in size, construction or function. The terms “upper” and “lower” in respect of the pump or dispenser are used only to distinguish the two halves and are not intended to imply any particular orientation of the parts in use.
As used herein a “semirigid” refers to a material having a flexural modulus of at least about 300, preferably at least about 500 MPa, measured using ASTM D790. Pump and dispenser parts herein made from a semirigid material are generally moulded with sufficient wall thicknesses that they are self-supporting, by which is meant that they will not substantially bend under their own weight. However, certain embodiments of reservoirs herein, such as flexible sachets, are non-self supporting structures through being made of thin laminates, even though the laminates may comprise semirigid materials.
By a “unitary moulding” is meant a moulding formed in a single piece or completely formed within a single mould. It may comprise only one material but the term “unitary moulding” also comprises workpieces formed from two or more materials in a common moulding operation such as a two-shot injection moulding where different materials are co-injected or sequentially injected into a common mould.
A “fluid” herein refers to a flowable liquid or gel.
“Monostable” as used herein in respect of an actuator or an element thereof means having a force-deflection curve including a priming region wherein the force initially increases for increasing deflection, in the manner of, say, a conventional spring, and then at some threshold force there is at least one inflection point such that further deflection of the element occurs with a reduction in the applied force. Such a curve is shown in
“Bi-stable”, in respect of an actuator or an element thereof, refers to an actuator or an element thereof that behaves like a monostable actuator or element until the defined force threshhold is overcome but then “flips” to stay permanently in a depressed position.
Dose Chamber
The pumps according to the invention comprise a dose chamber. The dose chamber is formed by the co-operation of the upper and lower pump halves when the pump is assembled. The dose chamber holds a single dose of the fluid to be dispensed which, in preferred embodiments, can be replenished from a reservoir in fluid communication with the dose chamber. The dose chamber is in fluid communication with a pump inlet port, through which fluid can be received from the reservoir, and a pump outlet port from which fluid can be dispensed. In certain embodiments illustrated herein the pump inlet and outlet ports are at opposite sides of the dose chamber and for many applications this will be the most appropriate geometry however the invention is not so limited. The inlet and outlet ports can be adjacent to each other or placed in any other position relative to each other and the dose chamber provided they perform their intended function of permitting fluid flow into and out of the dose chamber. Fluid flow into and out of the dose chamber is controlled by inlet and outlet valves described in more detail below. The pumps further comprise a resilient actuator, also described further below whose actuation results in the dispensing of a dose of fluid from the dose chamber. The volume of the dose dispensed by the pump will generally be less than the pump volume since actuation of the pump via the resilient actuator will generally not result in all of the fluid contained within the pump being dispensed. Dose volumes herein may vary from a few microlitres to several millilitres depending upon the pump dimensions and construction. The dose volume is preferably a metered dose substantially pre-determined by the dimensions of the dose chamber. Means for achieving this, comprising restricting a user's ability to modify the dose volume are described further below in the section on resilient actuators.
Before first use the dose chamber may require priming with the fluid to be dispensed. The greater the ratio of the pump volume to the dose volume the greater the number of priming strokes needed to replace air inside the unprimed pump with fluid drawn from a reservoir. The preferred number of priming strokes is three or fewer.
In a preferred aspect of the invention the dose chamber has a lower wall which creates an endpoint for the deflection of the resilient actuator and stops its movement when the actuator abuts it. Changing the distance between the actuator in its resting position and the lower dose chamber wall can provide a method for fine adjustment of the dose volume of the pump, thereby at least partially defining a metered dose. This is advantageous in a commercial production environment when different dose volumes need to be produced in a cost effective way. Of course, the dose volume can also be adjusted by changing other parameters such as the actuator shape and size.
Resilient Actuator
An important feature of the pump herein is the actuator. The actuator is preferably resilient. It can be a separately manufactured piece fitted to the upper pump half but is preferably an integral, resilient wall section of the upper pump half bounding the dose chamber. Resilience is provided by selection of the material from which the actuator is made and by control over its thickness and shape. Suitable materials for the actuator are thermoplastic elastomers, silicones, rubbers or soft grades of polyolefins (e.g. polyethylene or polypropylene). A suitable thickness for the actuator when manufactured from the same semi-rigid material as the pump body is from about 0.1 to 0.8 mm, preferably from about 0.3 to 0.7 mm, more preferably from about 0.4 to 0.6 mm. In an alternative embodiment, resilience may be provided by a two component system whereby a spring or other resilient apparatus is placed immediately beneath the actuating wall to return it to its unpressed position following actuation.
The actuator is depressed by a user in order to decrease the volume of the dose chamber and thus dispense a dose of fluid from the pump. For a resilient actuator, when the depressing force is removed, its resilience causes the actuator to spring back to its original shape causing a pressure reduction in the dose chamber to draw fluid into the dose chamber from a reservoir.
The design of the actuator influences the dose size and accuracy of the overall system. For many applications the precise requirement for the delivered dose is not so critical and dose tolerances of +/−20% are acceptable. Simple resilient actuators in form of buttons are well known in the art. The actuator can be integrally moulded with the upper pump half (in a manner similar to the gas bellows shown in U.S. patent application 2002/074359), co-moulded, overmoulded, or moulded separately and assembled via a mechanical snap or friction fit, such as in the pump of WO 98/08661, or attached via a welding operation.
Simple actuators can have the disadvantage that the user can choose the force applied whilst dispensing a fluid, which can lead to a big variation in dose quantity and quality. The relationship between the applied force and the degree of deflection of the actuator may approximate to linear, or at least require continuously increasing force for ever greater deflections. If a user only presses gently then the dispensed volume and pressure of the fluid may be suboptimal, resulting, for example, in incomplete or variable dosing, an undesirable spray pattern or poor particle size distribution. Although this may be acceptable for certain applications or products, applications in the area of medical devices typically require more rigorous dose tolerances, especially when delivering active pharmaceutical ingredients. In order to overcome this particular disadvantage the actuator herein preferably includes monostable or bi-stable elements. These elements are characterised in that they do not have a linear force-deflection relationship. The use of monostable or bi-stable elements in an actuator for a delivery system provides added control to a user's operation of the device.
The use of monostable elements in form of buttons or snap-domes is known in the electronics industry in form of input devices (keypads for mobile phones, calculators, etc) and circuit board switches. Snaptron Inc. of Loveland, Colo. 80537, USA distributes metal snap domes in various sizes and geometries. Monostable elements, in the form of “snap-domes” are known, for example, in switches from e.g., U.S. Pat. Nos. 4,933,522; and 5,510,584. The principle has also been disclosed for use in a sample type spray dispenser in U.S. Pat. No. 6,460,781. WO 02/016796, assigned to Valois S A, describes a two-leaved spring which acts a monostable element and can be used inside a dispensing reservoir. A further elaboration on this type of actuating element is described in U.S. Pat. No. 6,271,487 which discloses a switch having tactile feedback and three states of switching. Monostable elements are also used in the toy industry. Monostable elements as used herein can be separate elements, such as a snap dome located underneath the resilient actuator or they can be an integral feature of the actuator formed by appropriate construction of the actuator wall as disclosed in U.S. Pat. No. 6,460,781.
For monostable elements in an actuator the typical force-deflection curve is like that shown in
In a separate aspect of this invention there is provided an actuator for use with a dispensing pump, the actuator comprising a shaped, preferably disc-like, plate comprising an outer flange lying in a first plane and a central resiliently deflectable dome, the dome comprising an apex and at least one annular trough whereby, when the actuator is fixed at its outer flange, the actuator has, for forces applied perpendicularly to the first plane, a force-deflection curve that includes a priming region wherein the force initially increases for increasing deflection of the dome, and at least one inflection point such that further deflection of the dome occurs with a reduction in the applied force.
Typically, at some point past the threshold point on the force-deflection curve of the actuator, the applied force required to achieve further deflection increases again, usually as some material limit of the actuator is reached. A predefined endpoint for the deflection may also be achieved due to the actuator abutting some stopping element, in which case of course the applied force will increase very rapidly for slight or no further deflection. The deflection endpoint may be defined by the physical dimensions of the actuator or a further stop element can be introduced, such as the lower dose chamber wall.
For resilient actuators, when the applied force is removed then the actuator returns to its original undeflected starting point. Bi-stable actuators which stay in a permanently depressed position are not resilient as intended herein. Although this type of actuator is not suitable for repeated dosing, if several are used in one dispensing package it can have advantages for controlled dosing regimens. In a further aspect of the invention herein there is provided a reservoir containing a fluid to be dispensed, the reservoir comprising boundary walls and a fluid outlet, wherein the boundary walls of the reservoir comprise a plurality of bi-stable actuators such that each depression of a bi-stable actuator results in a substantially identical dose of fluid being dispensed from the fluid outlet. A preferred bi-stable actuator will present a convex dome to the exterior of the reservoir and, when depressed past its threshold, will permanently deform to present a concave depression to the exterior of the reservoir. The preferred embodiment of this further aspect of the invention comprises a reservoir having a plurality of externally convex deformable bi-stable actuators arranged in a regular array on one face of the reservoir, to give the appearance of a blister pack.
Valves and Valving Arrangements
Further important features of the pumps herein are inlet and outlet valves. The inlet valve is associated with the pump inlet port for controlling fluid flow through the inlet port and the outlet valve is associated with the pump outlet port for controlling fluid flow through the inlet port. By ‘associated with’ is meant that each valve is located in the respective port or in a flow channel directly connected to the port. If not located in the port then the valve can be upstream or downstream of the port provided it is able to perform its intended function of controlling fluid flow through the port. It is highly preferred that both the inlet and outlet valves are of the non-return type, allowing movement of fluid in one direction along a conduit or flow channel but preventing the flow of fluid in the reverse direction. Suitable valves include flap valves, duckbill valves, ball valves and slit valves. Flap valves are preferred for ease of in-situ moulding. In preferred embodiments the inlet and outlet valves are made from an elastomeric material having a Shore A hardness of from about 5 to about 90, more preferably from about 20 to about 70. Suitable elastomeric materials include thermoplastic elastomers and silicones and rubbers. The flap and slit valves can be various shapes such as rectangular or triangular or more complex shapes as described in more detail below. The valves can be co-injected, overmoulded, insert moulded as an extra part or separately assembled such as by welding, interference fitting or snap fitting. In an alternate embodiment the inlet and outlet valves are integrally moulded with either the upper or lower pump half from the same semirigid, thermoplastic material as the pump half with which they are integrally moulded. In a further alternate embodiment the inlet and outlet valves may be injection moulded as a single piece with a bridge of material connecting the two. This may enable separate manufacture and ease of installation into the pump body, and predetermined directional arrangement.
A preferred valve arrangement comprises an elastomeric valve mounted inside a flow channel, the valve comprising an upper surface, the upper surface being immovably fixed, preferably by injection moulding, to an upper flow channel wall, the valve further comprising a flap having a lower surface which is sealingly compressed against a lower flow channel wall in the absence of a differential in fluid pressure across the valve flap, wherein an increase in fluid pressure on against the lower surface of the flap lifts the flap from the lower flow channel wall and permits fluid to flow past the valve. In the embodiments herein it is preferred that the one of the upper or lower pump halves comprises the upper flow channel wall of the valve arrangement and the other of the upper or lower pump halves comprises the lower flow channel wall against which the lower surface of the valve flap is sealingly compressed. The lower surface of the valve flap is generally coplanar with the lower flow channel wall and the valve flap is oriented in the direction of fluid flow along the flow channel. If back pressure in the fluid should urge it to flow in the reverse direction, the fluid presses against an upper surface of the valve flap, sealingly compressing the flap against the lower flow channel wall and thereby increasing resistance to reverse fluid flow. By varying the profile of the valve, flap and/or by design of the upper and lower pump halves a desired threshold pressure for valve actuation can be set. Only when the pressure differential across the valve exceeds the threshold pressure is the valve opened. A normally closed valve system is beneficial, as it ensures that the pump only has to be primed once and it reduces the risk of contamination from outside. Preferably the threshold pressure for the valve is such that the outlet valve opens when the force applied to the resilient actuator is in the range from about 70% to about 100%, preferably from about 90% to about 100%, of the threshold actuation force for the resilient actuator.
In a particularly preferred valve arrangement the flow channel is restricted at the point where fluid flowing along it would first encounter the valve and the valve comprises a foot portion which is permanently compressed against the lower flow channel wall such that the only fluid passage past it is along a groove in the lower flow channel wall, the groove being flanked by side walls. The groove is bridged by a sealing ridge rising to the height of the side walls and the valve flap sits across the sealing ridge and the side walls preventing fluid flow until the fluid pressure rises sufficiently to lift the valve flap away from the sealing ridge and the adjacent side walls. More particularly two such valve arrangements are preferably used in tandem with the valves in each arrangement being separated from each other and a dose chamber being arranged on a fluid flow path intermediate the two valves such that the valves act as inlet and outlet valves for the dose chamber.
The pump herein without its resilient actuator can be used as a valve module and is useful in its own right since it can be combined with differently sized or shaped actuators to provide pumps with different characteristics, such as different dose volumes. The pumps and valving modules herein can of course be designed so that the valves are fixed to either the upper or lower pump halves.
Atomiser
In certain embodiments herein the pump or dispenser includes an atomiser associated with an outlet flow channel to break up dispensed fluid into a spray. The outlet flow channel can be formed from upper and lower outlet flow channel halves which are preferably integrally moulded with the upper and lower pump halves.
U.S. Pat. No. 6,059,150 illustrates a typical atomiser for a nasal spray application using a hollow nozzle adaptor which includes a spray orifice incorporating a swirl chamber geometry.
Alternatively, atomisers are known wherein a cup shaped component, including a spray orifice and swirl chamber geometry, is separately assembled to a nozzle adaptor, an example of such a component is the nozzle cap disclosed in U.S. Pat. No. 5,738,282.
These types of atomisers are typically separate units to the pump and subsequently need assembly to a pump unit. This is typically done via mechanical connection, such as a friction or snap fit and requires precise moulding and assembly effort to achieve a fluid tight seal. This necessarily imposes some limitations on the overall design of the delivery system.
A solution for a much more versatile atomiser design is disclosed in WO 01/89958 where the atomiser for an aerosol spray device is formed by two halves of a simple injection moulded component with tailor made geometry to allow atomisation of a particular fluid. Such an approach allows a greater design freedom for a spray delivery. device and offers greater means of controlling the spray characteristics for a wide range of products by shaping the flow channel geometry in a suitable way.
A plain dispensing orifice is sufficient for highly viscous fluids that cannot be broken up into small particles to form a spray. The orifice can be formed entirely within either of the upper or lower outlet flow channel halves or from a combination of part mouldings in both halves. Where a circular orifice is required then this can be done by moulding a semicircular channel in each of the upper or lower outlet flow channel halves. Due to the small dimensions and tolerances it can be difficult to exactly match the edges of top and bottom half. In order to eliminate this particular issue the orifice can be formed with one side being flat, therefore small variations in assembly positioning will not matter. This principle is illustrated in WO 01/32317. A dispensing orifice can also be formed entirely within either of the upper and lower outlet flow channel halves.
The dispensing orifice can also comprise a movable plug to seal the orifice when it is not in use. This can help avoid clogging of the orifice and also provides better protection from contaminants for fluid remaining in the dispenser. WO 03/078073 discloses an arrangement whereby a plugging element is movable between a sealing and non-sealing position upon operation of the device without other intervention by the user.
Reservoir
The purpose of the pump is to enable dispensing of a fluid from a fluid source or reservoir. The fluid can be any that is compatible with components of the pump and that is not too viscous to be pumped including, without limitation, cosmetic products such as perfumes and lotions; medicines; veterinary products, liquid foods or sauces and other household products such as cleaning fluids. The pump can be permanently or detachably connected to a reservoir and, optionally, an atomising nozzle or applicator, to form a complete dispenser and/or it can form part of a more complex product comprising other parts such as a housing and a handle. An atomising nozzle is preferred for certain medicinal applications, such as nasal or throat treatment. An applicator suitable for spreading the fluid onto a substrate may be preferred for other treatments. Useful applicators comprise spreading means selected from brush heads, elastomeric wiping blades and disposable cloths. The pump can be directly connected to a reservoir or connection can be made, for example by means of intermediate tubing if it is desirable for the pump and reservoir to be remote from each other. Provision for permanent attachment to a reservoir can be made, for example by co-moulding a weld spout with the pump inlet port so that the pump can be sealed in a fluid tight manner to a flexible sachet.
The pumps provided herein can be manufactured at low cost and are economically suited to applications where a pump is provided with each reservoir. In this case, the reservoir and pump are preferably permanently connected via a heat-sealing, welding, in-mould or snap fit operation. There are applications though, in particular where the pump is associated with a more complex device, where it can be beneficial for the reservoir to be detachably connected to the pump such that replacement reservoirs can be fitted to the same pump. Though a detachable connection avoids throwing away the pump if the reservoir must be replaced, it introduces further complexity in order to provide a reliable, fluid tight, re-usable connection. However, suitable fitments for this purpose are known in the art. Exemplary fitments are disclosed in WO 99/05446, WO 00/66448 and WO 03/095322.
The reservoir itself can be semirigid or flexible. If it is semirigid then it may be necessary to provide means for venting the reservoir, for example by means of a one-way valve allowing air ingress, in order to avoid the development of a vacuum in the reservoir which could inhibit further dispensing or cause suck-back past the pump outlet valve requiring the pump to be re-primed. The venting means can also comprise a narrow mesh filter that prevents fluid passing through it and escaping to the external environment. For example a biofilter that filters out bacteria, spores and the like from the in-drawn air, thus enabling the fluid in the reservoir to be preservative free. A biofilter capable of maintaining a sterile filtration barrier can be made from GORE-TEX® expanded PTFE laminate, available from W. L. Gore & Associates, Inc. of Newark, Del., USA. In preferred embodiments of a dispenser herein the pump is combined with a reservoir in the form of a flexible sachet containing a fluid, the sachet collapsing as fluid is withdrawn from it by the pump. A reservoir made of a flexible laminate offers the benefit of improved barrier properties. Flexible reservoirs are preferably charged with fluid via an airless filling operation so that the charged reservoir contains no air.
In many cases it will be convenient and simpler to manufacture the pump as an external fitment to the reservoir. However, where total space is a problem then the reservoir can be built around the pump so that the pump is internal to, or contained within, the reservoir, by which is meant that walls of the reservoir substantially enclose the pump even though parts of the pump, such as, in particular its actuator and a lower pump surface opposed to the actuator may be contiguous with upper and lower outside walls of the reservoir. Preferred embodiments herein include a dispenser comprising a reservoir with an integral pump contained within the reservoir. Alternately the pump can be contained within a flexible sachet so that the actuator of the pump can be actuated by pressing against that portion of the sachet wall which overlies the actuator, as shown for example in the device of WO 02/16047. Preferably, in embodiments with the pump contained within the reservoir, the pump upper and lower halves are integrally moulded with upper and lower halves of the reservoir.
Whether the reservoir is semirigid or flexible it may be preferable to include a dip tube inside the reservoir to assist the removal of all of the fluid in the reservoir in certain orientations dependent upon the orientation of the dispenser when in use. A dip tube will generally be used when the reservoir is semirigid and can also be useful in a flexible sachet. The method of construction of pumps, reservoirs and dispensers herein, from upper and lower moulded halves, can also be applied to the construction of dispensing devices and reservoirs with dip tubes, even if a pump is not incorporated. Thus in a further inventive aspect herein there is provided a dispensing device comprising upper and lower halves, the upper and lower halves co-operating to form a fluid reservoir and a dispensing outlet at a first end of the reservoir characterized in that the upper and lower halves each comprise sections of an integrally moulded channel, the sections co-operating to form a dip tube, or flow channel, in fluid communication with the dispensing outlet and terminating at an inlet end close to a second end of the reservoir remote from the first. The dip tube preferably has a length from the dispensing outlet end to its inlet end of at least 90%, preferably at least 95% of the length of the reservoir. In a preferred embodiment of this dispensing device at least one of its upper and lower halves comprises a resiliently deformable region enabling fluid to be pumped from the reservoir through the dispensing outlet. This resiliently deformable region may comprise a substantial proportion, say at least 30%, more preferably at least 50%, of the external area of the pump half comprising it. Alternatively the deformable region may be relatively small and be in the form of a resilient actuator as herein described, preferably comprising a monostable element. A further mechanism for dispensing fluid from the device comprises providing a plurality of bi-stable actuators, as described further above, such that compression of each actuator delivers a unit dose of the fluid. As for other embodiments herein, this dispensing device can also comprise an atomising nozzle in fluid communication with the dispensing outlet and, if necessary an outlet valve and a vent valve.
Manufacture of the Pump
In general the pumps, dispensers, valves, valve modules and actuators herein can be made by low cost making moulding techniques such as injection moulding, compression moulding and thermoforming. Injection moulding is preferred. However, it is also possible for at least one of the upper and lower pump halves to be compression moulded or thermoformed, and the present invention comprises pumps with compression moulded or thermoformed upper and/or lower pump halves comprising valves as herein described. Assembly of the component parts can be by snap or friction fit or by welding. Further sealing, where necessary, can be provided by additional injection moulded seals or by other techniques known in the art, such as ultrasonic sealing, laser welding or heat sealing.
In an embodiment, each of the upper and lower pump or dispenser halves is formed in one single shot injection moulding operation from a suitable, semirigid thermoplastic resin material. Alternatively, the upper and lower pump or dispenser halves may be assembled after moulding. Suitable resins include thermoplastics having a flexural modulus of at least 300, preferably at least 500 MPa, preferably at least 1000 MPa, measured using ASTM D790 and include polypropylene, polyethylene, polyethylene terephthalate (PET), polyesters, polycarbonates, polyamides, polystyrenes and blends thereof. Preferred materials include polypropylene, polyethylene and polyethylene terephthalate, most preferred is polypropylene. By careful choice of dimensions, flap valves can be integrally moulded with the upper or lower pump half in a single shot injection moulding process. Alternately, the valves can be co-moulded from a softer material in a two-shot injection moulding.
In certain embodiments it may be appropriate for all or part of the either the upper of lower pump half to be made of a more flexible material such as a thermoplastic elastomer. For example, an upper pump half may be substantially composed of a semirigid material with its resilient actuator being formed from a thermoplastic elastomer in a two shot injection moulding operation. In particular, the inlet and outlet valves can be and preferably are formed from a second resin material co-moulded with either of the upper and lower pump halves in a two-shot injection moulding operation. Conveniently this can be done within the same mould or tool as that employed for the first step. The second resin material is preferably an elastomeric material having a Shore A hardness, measured using ASTM D2240, of from 5 to 90, preferably from 20 to 70.
The upper pump half and the lower pump half are then assembled onto each other. Where flap valves are used, their compression takes place at this stage. Once the two pump halves are assembled, a sealing element can be formed by injecting an additional resin, bonding the sealing element to the upper and lower halves, thus holding them together and creating a fluid tight seal. An alternative option for sealing the upper and lower half together is the use of a welding operation, such as by high frequency sealing. A third option for assembly of upper and lower halves is to integrate a snap feature into one or both halves which enables the upper and lower halves to maintain the assembled position once brought together. In this case it may be necessary to use an O-ring or gasket to provide adequate sealing. In an alternative embodiment, a co-moulded TPE seal may be used.
Though in the preferred embodiment the preceding steps are all integrated into a single injection moulding process using one injection moulding tool, it will be appreciated that each be performed on separate, dedicated injection moulding tools.
If the resilient actuator has not been integrally moulded with the pump upper half then it can be made in a separate operation and assembled to form the completed pump via e.g., an in-mould sealing operation.
The invention will now be described in more detail by reference to preferred particular embodiments.
a shows, in perspective view, a flap valve used in the pump of
b is a perspective view of an alternate flap valve shape.
FIGS. 1 to 11 show a first embodiment of a pump according to the invention and its mode of operation.
Referring in more detail to
Upper pump half 102 is shown fitted with inlet and outlet flap valves 106 and 107, shown separately in
The upper pump half comprises resilient actuator 105 which is a thin wall section of the upper pump half where it bounds dose chamber 114.
Reference will now be made to FIGS. 9 to 11 to show more clearly the mode of operation of pump 101.
As shown in
FIGS. 14 to 16 show a second embodiment according to the invention which is a dispenser 250 comprising a pump having essentially the same construction as that of
A very different solution for a dispenser according to the invention is shown in FIGS. 17 to 20 which represent a third embodiment of the invention. In this embodiment the whole dispenser 350, including reservoir 320, is integrally moulded with pump 301 in two halves. The advantage of following this approach is that an entire multiple controlled-dose dispenser can be obtained with a minimum of parts and moulding/assembly operations. Compared to the dispenser 250 shown in FIGS. 14 to 16 this solution provides a more compact dispenser for the same amount of contained fluid as it utilises the otherwise unused space by building the reservoir around the pump so that the pump is internal to the reservoir. The need for the reservoir to be moulded imposes some restrictions on the materials that can be used for the reservoir, for example laminates will generally be unsuitable, but this may not be critical for many applications. This design also requires a process for sealing two areas: a first, inner, seal which isolates the pump components, including outlet flow channel 317, from the reservoir 320 and a second, outer, seal at the outer perimeter which seals the reservoir 320 from the outside air. With this design the inner seal can no longer be created via an injection moulded joining element as in the pump of
Reservoir 320 is in the form of compartments symmetrically disposed about pump 301 and inlet and outlet flow channels 316 and 317. The inlet and outlet valves are not shown in the Figures but operate in the same way as already described in relation to FIGS. 9 to 11 such that, after a dose of fluid has been dispensed from dose chamber 314, fluid is drawn from the reservoir via inlet flow channel 316 to recharge the dose chamber. Though it is not shown in the Figures it is highly preferred that the reservoir is also fitted with a vent membrane filter to keep the reservoir at atmospheric pressure. During initial manufacture the reservoir is filled with fluid via fill port 381 after the assembly of the upper and lower halves 302 and 303, the port then being sealed with fill port plug 380 which may be integrally moulded to either the upper or lower halves 302 and 303. It will be appreciated that dispenser 350 can be various shapes and thicknesses and sized to suit the particular application. It can also be moulded with a shoulder for receiving a protective cap. In preferred embodiments for medicament dispensers the dispenser has a length of from about 20 to about 100 mm, more preferably from about 40 to about 70 mm, a width of from about 15 to about 80 mm, more preferably from about 20 to about 55 mm and a depth of from about 5 to about 10 mm. The reservoir preferably has a volume of from about 0.5 to about 40 mls. Of course for other applications much larger reservoirs may be appropriate.
Whilst dispenser 350 can incorporate an integrally moulded actuator as part of the upper half 302, as described in the first embodiment, FIGS. 21 to 23 show in more detail a composite resilient actuator 305 used in the third embodiment. The actuator comprises a separate monostable button 340 covered on top and bottom surfaces by a soft, elastomeric material to form the resilient actuator. The separate monostable element can be made of various materials, in this embodiment it is a commercially available metal snap dome from Snaptron Inc. The actuator is insert-moulded into upper pump half 302 where it is located and fixed by means of positioning lugs 341.
The resilient actuator 405 of this embodiment is a thermoformed, polypropylene disc insert-moulded to a corresponding recess on upper half 402. The actuator is shown in section in
Referring again to
Referring now to
As seen most clearly in
When the actuator 505 is depressed with sufficient force, fluid in the dose chamber, located between dose chamber lower wall 522 and the actuator 505, is dispensed through outlet valve 507, located in outlet port 513, and passes along the portion of the outlet flow channel 517 formed between the upper and lower halves 502 and 503. The fluid then flows through a connecting channel formed in the upper half and along the remaining section of outlet flow channel 517 that lies between the outlet flow channel upper wall 521 and the upper pump and dispenser half before being dispensed through the exit orifice.
When the actuator is released, fluid from the reservoir 520 is drawn along the section of inlet flow channel 516 lying between the upper pump and dispenser half 502 and one of the strip extensions of the actuator. The fluid then passes through inlet valve 506 and along the section of inlet flow channel 516 formed between the upper and lower halves 502 and 503, from where it passes through pump inlet port 512 into the dose chamber. Though not shown in the Figures, the reservoir of this embodiment, like that of the dispenser of the fourth embodiment can further comprise a vent valve such that the pressure inside the reservoir is maintained at atmospheric pressure. A microfilter in the vent valve can substantially prevent outside contamination of fluid in the reservoir.
Finally, a sixth embodiment of the invention is a valve module as illustrated in FIGS. 32 to 35. The valve module can be manufactured as a separate item for assembly to variously shaped pump or dispenser constructions, thus providing greater manufacturing flexibility. The valve module comprises upper and lower halves 602 and 603. Lower half 603 comprises a flat injection moulded strip having a central groove which forms the basis for inlet and outlet ports 612 and 613. The groove is interrupted by inlet and outlet sealing ridges 608 and 609 against which the flaps of inlet and outlet valves 606 and 607 are compressed, preventing the flow of fluid along the groove until sufficient pressure is exerted by the fluid to lift the valve flaps (during dispensing in the case of outlet valve 607 or during dose chamber recharging in the case of inlet valve 606). An upper surface of the upper half 602 provides lower dose chamber wall 622. A channel passes through the centre of this to provide fluid communication between the dose chamber and the inlet and outlet ports. The lower dose chamber wall is bounded by a raised annular boundary wall 631 for receiving an actuator or interacting with a dispenser, as shown in
The following list provides a key to the part numbers used in the figures and their foregoing description. The same part number may be referred to in different embodiments of the invention and will be prefaced by a number indicating the number of the embodiment. Thus a ‘pump inlet port’ number below as ‘12’ will appear as 112 when referred to as a part of the first embodiment but 612 when referred to as a part of the sixth embodiment. For consistency of numbering, a single digit number below will be padded with a leading zero to two digits before the embodiment number is appended. Thus, a ‘resilient actuator’ (number 5 below) will appear as 405 in the description when described as a part of the fourth embodiment. Not all parts are described or necessarily used in each embodiment.
All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by reference, the meaning or definition assigned to the term in this written document shall govern
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 04253005.5 | May 2004 | EP | regional |
