GB2450877A - Sprayer with internal mixing device on dip tube - Google Patents

Abstract

A hand held sprayer 1 has an internal bag 12 containing product to be sprayed. The sprayer features an internal mixing device 15 which may be carried on the dip tube 14,16 and contains a reagent which allows causes chemical modification of a contained liquid, before ejection from the sprayer. The bag and valve structures 12,6 provide a typical sterile sprayer arrangement in that air drawn in at valve 6 during spraying, does not contact the contained liquid due to the barrier provided by the bag 12. The reagent may be a chlorine release agent in solid form, and the liquid may be a dilute aqueous acid. The sprayer may be used in sterile cleaning applications.

Description

SPRAY DISPENSER

The present invention relates to an improved spray dispenser, such as a trigger spray dispenser, in particular for providing an aqueous disinfectant spray.

Disinfectant solutions are widely used within validated clean rooms and sterile work areas in biological, biochemical, pharmaceutical and medical facilities. Guidelines now insist upon the certified sterile status of disinfectants employed in medical cleanrooms within the critical A and B zones. In practice, this means that it is operationally practical and advisable to employ sterile disinfectants throughout the facility, including zones C and D. It is increasingly desirable to avoid those disinfectants whose residues during and after use might give rise to contamination issues Disinfectants for use in clean room environments must be intrinsically sterile along with their packaging and delivery systems when brought into service, so as not to compromise the validation of the facility in which they are to be deployed.

Currently, aerosol or spray dispensers are commonly used for dispensing sprayed sterile or reactive fluids in clean room environments.

Aerosol spray dispensers use an aerosol cartridge to provide compressed gas for atomising the liquid product and driving it out through the nozzle. However, it is now apparent that certain of the gases most often used in spray cartridges, such as fluorocarbons, are toxic and harmful to the environment.

Spray dispensers fitted with manual spray pumps are also known. In such a dispenser a liquid spray bottle is fitted with a manually operable pump which has a spray nozzle at the mouth of a liquid container. When the pump is operated, the liquid is drawn up to the spray nozzle through an inlet tube which extends into the liquid container, and is sprayed out through to spray nozzle. For this arrangement to work the spray bottle must normally be open to the outside atmosphere for the purpose of admitting ambient air into the container when the spray pump is operated to replace the liquid that is pumped out. This mechanism of action is unacceptable for sterile liquids and in a clean room environment, since the liquid in the container may be contaminated by particles, including bacteria, present in the ambient air.

GB-A-2333129 and WO-A-200401468 describe manual trigger spray dispensers in which a disinfectant solution is stored in a collapsible bag within a vented housing. The bag described is in sealing engagement with the trigger pump, and air is prevented from flowing into the bag. The bag collapses as liquid is dispensed. In this way, contamination of the bag contents by ambient air is avoided. Furthermore, the dispenser can be operated in any orientation since there is minimal headspace inside the bag at all times during dispensing.

However, many disinfectant solutions which are effective against spore-forming micro-organisms rely for their effectiveness upon their ability to make available oxidative radicals, such as reactive oxygen (including peroxide and superoxide), persuiphate andlor halogen or oxyhalide (hypohalite), which rapidly disable life processes that are otherwise protected within the spore.

By their very nature such oxidative radicals are unstable in solution and difficult to deliver quantitatively in reliably validated form. Gamma irradiation (required for sterilization) promotes premature decomposition and loss of dissolved free radicals in an unpredictable way. Furthermore, disinfectant solutions containing these radicals can react with container materials such as plastics causing embrittlement and contamination.

The present invention seeks to overcome these problems while retaining the advantages of the trigger spray format.

In a first aspect, the present invention provides a spray dispenser comprising: a collapsible liquid storage bag having an outlet opening; a manual spray pump mechanism sealed in liquid-tight fashion to the outlet opening of the collapsible liquid storage bag; and a conduit providing a flow path for liquid from inside the storage bag to the spray pump mechanism, said conduit extending from the spray pump mechanism to a liquid inlet located inside the collapsible liquid storage bag, and wherein the conduit includes a storage region in the liquid flow path, said storage region containing a reagent for chemically modifying the liquid.

The reagent is not in contact with the liquid in the collapsible bag prior to activation of the dispenser. Suitably, the conduit is substantially filled with air or an inert gas which provides a barrier between the reagent and the liquid prior to activation of the dispenser.

The dispenser is activated by bringing the liquid into the conduit and the storage chamber, where it contacts the reagent and reacts therewith to produce an activated liquid. The greater density of the activated liquid causes it to flow back down the conduit where it mixes with the rest of the liquid in the collapsible bag to produce the desired active solution for dispensing.

Suitably, the dispenser is activated by actuating the pump to draw liquid into the conduit.

it will be appreciated that activation of the dispenser could also take place if liquid is allowed to pass into the storage chamber under gravity, for example by inverting the dispenser. This could allow the dispenser to be activated by inverting, followed by shaking.

Premature activation of the dispenser by accidental or partial inversion thereof may be minimised by various measures, such as (a) use of a conduit that is at least partially hydrophobic, especially at a liquid inlet region thereof (b) use of a conduit having a small diameter, again especially at a liquid inlet region thereof, (c) suitable configuration (e.g. tortuous) of the conduit, or (d) a barrier located in the conduit upstream of the reagent chamber, wherein the barrier can be ruptured by the pressure differential created by operation of the pump. The dispenser or a secondary packaging thereof may comprise a "tilt-evident" label to warn of possible premature activation.

The dry reagent in the storage region has greater sterilization stability and storage stability than the active biocidal solution. Furthermore, the liquid in the collapsible bag container typically does not contain reactive biocidal species such as free radicals or chlorine prior to mixing with the reagent in the conduit. Consequently, the liquid does not cause degradation of the collapsible bag or other components during storage. These features allow the dispensers according to the present invention to be packaged in secondary packaging, sterilized, and stored for long periods before use, without loss of effectiveness. Because the bag collapses as liquid is dispensed, little or no back pressure (vacuum) exists inside the container, so ambient air is not drawn into the container during dispensing. Furthermore, the bag remains full of liquid throughout the dispensing operation so that an inlet end of the conduit remains immersed in liquid and the dispenser can be used in any orientation.

The collapsible bag may be formed of any suitable, water-impermeable sheet material such as a plastic monolayer or laminate film. Suitable materials for forming the sheet material include polyolefins, polyesters and polyamides. The liquid capacity of the bag is typically from about I OOml to about I 500m1, for example from about 250ml to about l000ml. The collapsible bag normally has a single outlet that is sealed in liquid-tight fashion to the pump or the outlet tube to form a hermetic enclosure for the liquid. The liquid-tight seal between the pump and the collapsible bag may be a permanent bond, or it may be a releasable engagement for example as described below.

The manual spray pump may be any of those suitable for manual spray dispensers. The pump is manually activated to create a differential pressure to dispense liquid from the collapsible bag through a nozzle. The manual spray pump is typically a trigger spray pump. The pump suitably includes a nozzle for ensuring liquid is dispensed as a spray.

The pump preferably further includes a one-way valve such as a needle valve, slit valve or poppet valve to resist the flow of any ambient air through the pump into the collapsible container bag. The operation and construction of manual spray pumps for hand-held dispensers is conventional, and will not be described further here.

The spray dispenser of the present invention preferably further comprises a rigid or semi-rigid container enclosing the collapsible bag. The container provides rigidity and dimensional stability to the dispenser, in particular so that it can stand up and for convenience of handling. The container is typically formed of a blow-moulded polymer such as polyethylene, polypropylene or polyethylene terephthalate. The container suitably comprises a base for supporting the container upright on a level surface, and side walls. It goes without saying that the container should have at least one opening through which liquid can be extracted from the collapsible bag inside the container by the pump. Suitably, the opening is a tubular container neck having one or more fittings for attachment to complementary fittings on the pump. For example, the container neck may have internal or external thread projections, bayonet projections, or snap-fitting projections for engagement with complementary projections on a skirt or plug of the pump to secure the pump to the container. In certain embodiments, the outlet of the collapsible bag may be bonded in liquid-tight fashion to the neck of the container, and the pump is then secured to the neck in liquid-tight fashion with the conduit extending through the neck into the collapsible bag.

The container should also be provided with at least one an air vent to allow air at ambient pressure to enter the container externally of the collapsible bag during dispensing to prevent a pressure drop inside the container as the liquid is extracted from the collapsible bag. The air vent may be associated with the liquid extraction opening, or it may be a separate aperture in the container.

The conduit extends from the pump into the collapsible bag to draw liquid from inside the collapsible bag into the pump along a flow path inside the conduit. The conduit is normally substantially tubular along most or all of its length. The conduit includes a storage region in the flow path, where the liquid reacts with the reagent retained within the storage region to chemically modify the liquid. The storage region is suitably a storage chamber of enlarged diameter (i.e. larger diameter than the conduit generally, provided at a location along the flow path defined by the conduit. The storage region may be formed integrally with the rest of the conduit, but more usually it is a separate enclosure of liquid-impermeable material having an inlet opening (usually communicating with the liquid inside the collapsible bag through a length of tube) and an outlet opening that communicates with the pump through a tube. The storage region may contain structures for retaining the reagent, such as porous plates or a porous support element for the reagent. The internal volume of the storage region is suitably from about Sml to about I OOml.

As already noted, the storage region contains a reagent for chemically modifying the liquid. Suitably, the reagent is a solid reagent, which may be retained by suitable porous plugs or may be dispersed in a porous matrix in the storage region. Solid reagents, in particular solid reagents having low moisture content such as less than about l5wt.% water content, are more stable to sterilization by gamma-irradiation. The reagent may undergo chemical reaction with the liquid, for example to generate active oxygen radicals or chlorine. In other embodiments, the reagent may simply dissolve in the liquid.

Suitably, the reagent is a biocide reagent that reacts with or dissolves in water to form a biocidal solution. Suitably, the biocide reagent is present in the storage region of the conduit in an amount relative to the liquid in the collapsible container sufficient to provide a final solution after treatment having the desired biocidal properties. Suitably, the reagent is present in the treatment region in an amount relative to the liquid in the collapsible bag sufficient to provide a solution that gives a log reduction in spore count of at least about 3.0, more preferably at least about 4.0, according to the EN137004 protocol.

Suitable dry biocidal reagents that are stable to gamma irradiation include chlorine release agents, i.e. compounds that release chlorine in the presence of water. The chlorine release agent may for example be selected from the group consisting of N,N- dichlorazodicarbonamidine; sodium p-toluene sulphonchloramide; p-toluene sulphon- dichloramide; sodium benzene suiphonchioramide; succinchioride; p-sulphon-dichloramidobenzoic acid; 1,3-dichloroo-5-5-diethyl hydantoin; trichloroisocyanuric acid; sodium dichloroisocyanurate; sodium dichloroisocyanurate dihydrate; potassium dichloroisocyanurate; trichloromelamine, and mixtures thereof. The preferred chlorine release agents are dichloroisocyanurates, in particular sodium dichloroisocyanurate dihydrate (NaDCCN).

Preferably, the chlorine release agent is present in the storage region in an amount relative to the liquid in the collapsible bag sufficient to provide a total chlorine concentration in the liquid of from about l000ppm to about 3000ppm by weight. That is to say, the amount of chlorine release agent in the treatment region and the amount of liquid in the collapsible bag are selected such that the total chlorine in all chemical forms in the solution after complete mixing is in this range. It has been found that, for the chlorine release agents, a concentration of from about 0.1% to about 1% w/w, preferably from about 0.15% to about 0.5%w/w in water provides the desired solutions. Of course, not all of the chlorine in the solution is available to act as a biocide. Some may still be in chemical forms that are relatively inactive. However, preferably, the chlorine release agent is present in an amount and form sufficient to provide a free chlorine concentration in the liquid of at least about l000ppm, for example from about I000ppm to about 3000ppm by weight. The "free" chlorine concentration is measured using colour-change test strips available from numerous suppliers under the Registered Trade Mark SENSAFE and described in US-A-5,49 1,094.

In other embodiments, the reagent in the conduit may comprise a composition that reacts with water to produce hypohalite ions, such as a hypochlorite ions. The source of hypohalite may comprise a hypohalite salt, such as an alkali metal hypochlorite salt. In other embodiments, the source of hypohalite may be dichloramine 1. In yet other embodiments, the source of hypohalite may be a mixture of effective amounts of a halide salt and an oxidizing agent such as a persuiphate that reacts with the halide in the presence of water to generate hypohalite salts. The reagents preferably further comprise sulphamic acid, which forms an addition salt with hypochiorite to improve its stability and activity. The compositions may further comprise a soluble, non-reducing acid such as malic acid or succinic acid. Suitable compositions for generating biocidal hypohalite solutions are described in GB-A-2078522, GB-A-2164851 and GB-A-2187098.

The collapsible bag contains a liquid, and preferably the liquid substantially fills the collapsible bag so that there is minimal head space inside the bag. Suitably, the collapsible bag contains an aqueous liquid, preferably a sterile aqueous liquid. Suitably, the liquid is water, optionally having dissolved therein acidifying agents, surfactants or other additives. For example, the liquid may be an aqueous acid, preferably having pH in the range of from about I to about 4, preferably about 2 to about 3. The water may be buffered to acid pH with suitable buffer systems. Suitable acids and buffers include those based on organic carboxylic acids such as citric acid. The most preferred acidulantlbuffer system is acetic acid/acetate.

It has been found that the free chlorine content and the sporicidal activity of chlorine release agents are substantially enhanced if the water in the collapsible bag is acidified.

Similarly, the biocidal activity of hypohalite ions is greatly increased in acidic solution.

The aqueous solution in the collapsible bag may further comprise other compounds such as a detergent, for example sodium alkylbenzene suiphonate, or sodium lauryl sulphate, or a detergent builder, for example sodium carbonate, sodium metasilicate, or sodium sulphate.

A dye that it is bleached by the biocidal active species may be incorporated into the aqueous solution to provide a visual indication of the status of the solution with regard to the exhaustion of its disinfecting properties.

The currently most favoured system is based on a chlorine release agent, preferably a dichioroisocyanurate, as the chemical reagent in the reaction zone of the conduit, and acidified water (pH 2-4) as the liquid in the collapsible bag, the relative amounts being adjusted to about 0.lwt.%-0.2wt.% biocide based on the weight of the water.

A further advantage of the present invention is that the collapsible bag arrangement ensures that the liquid will always be accessible to the pump mechanism that draws the liquid material from the bag, regardless of the orientation of the spray dispenser, provided that there is minimal head space in the collapsible bag after filling. Suitably, the headspace in the collapsible bag afler filling and sealing is less than about 20% of the volume of liquid inside the collapsible bag, more suitably it is less than about 10% of said volume, for example less than about 5% of said volume.

Suitably, the dispenser according to the present invention is sterile both inside and out, and is contained within one, two or more successive layers of microorganism-impermeable outer packaging to maintain sterility. The multiple layers of packaging are discarded progressively as the products proceed from general storage into the closed sterile environment.

Generally, the dispenser and contents are stable to y-irradiation before use. For example, the dispenser and contents are stable to a typical sterilizing gamma flux of 25-40 kGy.

The term "stable" signifies that less than about 10%, preferably less than about 2%, and most preferably less than about 1% of the liquid or the biocide is chemically changed by the irradiation. Gamma (y) irradiation at appropriate flux (25-40 kGy) is commonly employed in order to sterilise these items contained within multiple layers of packaging.

Suitably, the dispenser according to the present invention further comprises a sterility indicator that gives a detectable, e.g. visual indication when the dispenser has been exposed to a stenlising dose of gamma irradiation.

A specific embodiment of the present invention will now be described further, by way of example, with reference to the accompanying drawing, in which: l0 FIG. I is a schematic, partially cut-away side view of a trigger spray dispenser according to an embodiment of the present invention; and FIG. 2 is a detailed longitudinal cross section through a region of the spray dispenser of Fig. 1.

Referring to Figs. I and 2, a trigger spray dispenser according to the present invention designated generally by the reference character 1, comprises an outer container 2 of blow moulded polyethylene having a base 3, side walls 4 and a threaded tubular neck 5 at the top. The outer container is shaped for convenient single-handed lifting and dispensing.

A venting aperture 6 is provided in the outer container to allow ambient air into the container to prevent a pressure drop inside the outer container as the liquid is dispensed.

A trigger spray pump 9 of conventional manufacture is sealingly secured to the container neck 5 in conventional fashion by engagement of threads on a tubular skirt 10 of the pump 9 with complementary threads on the container neck 5. A cylindrical sealing plug 11 extends downwardly from the pump 9 into the inside of the container neck 5.

A collapsible, liquid-filled bag 12 made of, for example, rubber, polyethylene, polypropylene, or polyvinyl chloride sheet material is located inside the outer container 2. The bag 12 is bonded in airtight and liquid-tight fashion around the outside surface of the sealing plug ii, and is clamped in liquid-tight fashion between the sealing plug 11 and the inside of the container neck 5. There is no fluid communication between the bag 12 and the interior of the container 2, and consequently the bag 12 collapses inside the container 2 as liquid is withdrawn from the bag and ambient air flows into the container through venting aperture 6.

The pump assembly further comprises a conduit to the trigger pump. The conduit extends into the inside of the collapsible bag for extracting liquid from the collapsible bag into the trigger pump for dispensing. The conduit comprises a first section 14 connecting the pump to the reaction chamber 15, and a second section 16 extending from the reaction chamber 1 5 to liquid inlet opening 17. The conduit sections and reaction chamber are formed from suitable plastic materials such as PVC or a polyolefin. The second section 16 is suitably made from a hydrophobic plastic material such as polyethylene. The conduit is substantially completely filled with air before operation of the dispenser. It has been found that the dispenser can be tilted to within about 10 degrees of horizontal without any ingress of the liquid into the conduit.

The reaction chamber 15 contains solid NaDCCN 18 held in place by porous plugs 19,20. The amount of NaDCCN is calculated to give a biocidal solution containing about 3000ppm of chlorine when completely mixed with the aqueous solution in the collapsible bag.

In use, the pump is actuated to draw liquid into the conduit, where it mixes rapidly with the NaDCCN to produce a dense solution that flows back into the collapsible bag.

Equilibration of the solution in the collapsible bag is achieved rapidly to give a homogeneous solution that can be dispensed with the spray pump.

The above embodiment has been described by way of example only. Many other embodiments falling within the scope of the accompanying claims will be apparent to the skilled reader.

Claims (10)

1. A spray dispenser comprising: a collapsible liquid storage bag having an outlet opening; a manual spray pump mechanism sealed in liquid-tight fashion to the outlet opening of the collapsible liquid storage bag; and a conduit providing a flow path for liquid from inside the storage bag to the spray pump mechanism, said conduit extending from the spray pump mechanism to a liquid inlet located inside the collapsible liquid storage bag, and wherein the conduit includes a storage region in the liquid flow path containing a reagent for chemically modifying the liquid.

2. A spray dispenser according to claim 1, further comprising a rigid or semi-rigid container enclosing the collapsible bag and an air vent to allow air at ambient pressure to enter the container during dispensing.

3. A spray dispenser according to any preceding claim, wherein the storage region is a storage chamber of enlarged diameter provided at a location along the flow path defined by the conduit.

4. A spray dispenser according to any preceding claim, wherein the storage region contains a solid reagent that reacts with, or dissolves in, water to produce a biocidal solution.

5. A spray dispenser according to claim 4, wherein the reagent comprises a chlorine release agent.

6. A spray dispenser according to claim 4, wherein the reagent comprises a halide salt, an oxidizing agent that reacts with the halide salt in the presence of water to generate hypohalite salts, and sulphamic acid.

7. A spray dispenser according to any preceding claim, wherein the collapsible bag is filled with a sterile aqueous liquid consisting essentially of water, an acidifying agent to acidify the water to pH 2 to 4, and optionally one or more surfactants.

8. A spray dispenser according to claim 5, wherein the collapsible bag is filled with a sterile aqueous liquid, and the chlorine reagent is present in the storage region in an amount relative to the liquid in the collapsible bag sufficient to provide a solution containing a total chlorine concentration of from about I 000ppm to about 3000ppm by weight.

9. A spray dispenser according to any preceding claim, wherein the collapsible bag is filled with a sterile aqueous liquid, and the biocide is present in the storage region in an amount relative to the liquid in the collapsible bag sufficient to provide a solution that gives a log reduction in spore count of at least about 3.0 according to the EN137004 protocol.

10. A packaged sterile spray dispenser comprising a spray dispenser according to any preceding claim, and at least one layer of microorganism-impermeable outer packaging surrounding the dispenser, wherein the dispenser within said outer packaging is sterile.