GB2349184A

GB2349184A - Liquid dispenser

Info

Publication number: GB2349184A
Application number: GB9911929A
Authority: GB
Inventors: Andrew Philpotts; Frank N Carrick
Original assignee: AGMA PLC
Current assignee: AGMA PLC
Priority date: 1999-04-23
Filing date: 1999-05-21
Publication date: 2000-10-25
Also published as: GB9909498D0; GB9911929D0

Abstract

A liquid dispenser 12 for expelling predetermined doses of liquid from a cartridge 14 comprises: a cartridge holding receptacle (figure 3), a lever 18 capable of flexure up to a predetermined maximum extent, and a plunger 24, wherein the lever 18 is coupled to the plunger 24 such that flexure of the lever 18 to the maximum extent advances the plunger 24 a predetermined distance into the receptacle. Ratchet means 22 is provided so that on return of the lever to a starting position following flexure of the lever, no substantial displacement of the plunger occurs, so that the plunger can be advanced through the receptacle step-wise. The ratchet means can also allow a slight retraction of the plunger on release of the lever. Also disclosed is a cartridge 14 for use in the dispenser, which incorporates a non-drip nozzle valve 42 to prevent accidental leakage of the fluid. The cartridge and dispenser can be used to sanitise a plurality of toilets.

Description

LIOUID DISPENSER The present invention relates to a liquid dispenser for dispensing predetermined doses of a liquid from a cartridge. The present invention further relates to a liquid container cartridge for use in the dispenser of the invention.

In aircraft, the toilets are usually recirculating closet and tank systems. There is a concern with aircraft sanitation since it is believed that the effluent tanks present a biomass lined with biofilm which in turn potentiates the transmission of pathogens from one place to another. It is therefore desirable to provide a means for the effective sanitation of such toilets. It is also desirable to provide a means for sanitation that leaves evidence that the sanitation has been performed recently, for example by exhibiting a blue colouring in the toilet post sanitation and/or the presence of perfuming or deodorising effects.

Furthermore, the means for sanitation will be required to meet the compatibility standards for use on aircraft detailed in AMS 1476B. In particular, the sanitation means must be able to cope with storage and use under conditions of varying barometric pressure such as those encountered in pressurized aircraft, and be essentially noncorrosive towards a range of metals, alloys and plastics employed in aircraft construction.

It is currently normal practice in aircraft to use solid toilet sanitising chemicals in the form of a powdered or tablet-form dosed products, one dose being added to each toilet at predetermined intervals. The solid product is typically presented in water soluble polyvinyl alcohol (PVA) sachets. This dosing is particularly desirable in certain older commercial aircraft, such as the Boeing 747, which have up to 17 self-contained toilets each with its own 50 litre recirculation tank, such that each self-contained system must be filled and dosed with toilet additive separately.

It has been noted that these powdered products, which are generally quaternary ammonium chloride (QAC) based, precipitate an adhesive'tar"within the effluent tank as a result of the chemical and/or physical interaction with the dissolve PVA, coffee/tea residues and urine.

Liquid products have been used to sanitise toilets on land. However such liquid products have not hitherto been suitable for use on aircraft because the liquid containers are prone to leak under conditions of varying barometric pressure. Toilet sanitising products are generally highly stain-forming and irritant to skin, eyes and nose, rendering such leakage highly undesirable inside an aircraft.

In view of these problems, it would be desirable to provide a new clean and efficient means for storing and dispensing liquid sanitation products.

In a first aspect, the present invention provides a liquid dispenser for expelling predetermined doses of liquid from a cartridge, said dispenser comprising: a cartridge holding receptacle, a lever capable of flexure up to a predetermined maximum extent and a plunger, wherein the lever is coupled to the plunger such that flexure of the lever to the said maximum extent advances the plunger a predetermined distance into the receptacle.

Preferably, the liquid dispenser further comprises a pistol-type grip extending sideways from the dispenser. More preferably, the lever extends obliquely adjacent to the pistol-type grip, whereby flexure of the lever to operate the dispenser can be achieved by squeezing the lever and the grip together with one hand.

Preferably, the dispenser further comprises a handle opposite the lever. The handle enables the dispenser to be held and aimed by a single operator using one hand to grasp the handle, while the other hand of the operator operates the lever to dispense liquid from the dispenser.

Preferably, the dispenser according to the present invention further comprises means to return the lever to a starting position following flexure of the lever without displacement of the plunger. More preferably, this means comprises biasing means such as a spring. Preferably, the dispenser comprises ratchet means whereby the lever is returned to its starting position substantially without displacement of the plunger, whereby the plunger can be advanced through the receptacle stepwise by repeated flexure of the lever.

Preferably the ratchet means also allows a slight retraction of the plunger upon release of the lever to release. the pressure of the plunger against a piston of a cartridge mounted within the liquid dispenser.

Preferably the ratchet means comprises a linkage biased into light engagement with a shaft of the plunger by a spring, so that upon release of the lever, a slight retraction of the plunger is effected.

Preferably the plunger comprises a small diameter boss for driving a piston of a cartridge. This allows pressure specifically to be applied at a central portion of a piston in a cartridge.

Preferably, the liquid dispenser is configured such that the predetermined distance advanced by the plunger is less than 20% of the length of receptacle, more preferably less than 10% of the length of the receptacle, and still more preferably less than 5% of the length of the receptacle. This enables the dispenser to be used to dispense respectively at least 5,10 or 20 doses from the receptacle without recharging the receptacle.

Preferably, the liquid dispenser according to the present invention further comprises a safety catch to prevent inadvertent operation of the dispenser. Preferably, the safety catch blocks movement of the lever and/or of the plunger when it is in a locking position. More preferably, the safety catch is biased into the locking position at which it prevents inadvertent operation of the dispenser.

More preferably, the safety catch is juxtapositioned with a handle or grip of the dispenser so that in use a hand of an operator grasping the handle or grip is positioned to operate the safety catch whilst still grasping the handle or grip.

The plunger of the dispenser according to the present invention may be provided with a piston for expelling liquid from a container received in the receptacle of the dispenser. More preferably, the plunger is adapted to drive a piston provided in the base of the container. The piston may be resilient so that flexure thereof changes the internal volume of the container. Thereby, upon driving the piston with the plunger, the piston flexes and advances to drive out liquid from the container. However, upon slight retraction of the plunger, the piston will revert to its former shape, whilst remaining in its advanced position, thereby reducing the pressure within the container. This will prevent inadvertent leakage of liquid from the container. More preferably, at least a region of the piston is resiliently deformable between a concave dispensing configuration and a convex resting configuration, said concave and convex configurations being taken from the perspective of the outside of the cartridge. In this manner, when pressure is applied, the piston deforms to concave, and then drives the fluid in the concave dispensing configuration. A slight retraction of the shaft allows the piston to resume its convex, or relative convex position. This deformation to rest position drops the internal pressure within the container, which will, for example, invert a non-return valve such as a sphincter valve, to its own"concave", or sealed, rest position.

Preferably, the liquid is expelled from the dispenser through a nozzle provided at a forward or front end of the dispenser, opposite the plunger. The nozzle may form part of the dispenser, but preferably the nozzle is provided on the container received in the receptacle of the dispenser as described further below.

Aircraft toilets of the older, self-contained type are provided with a flap in the base of the toilet that can obstruct the flow of sanitising liquid into the system. Therefore, the dispensing system according to the present invention preferably further comprises a probe projecting from a forward end of the receptacle. The probe can be used to displace the flap at the base of such toilets to assist injection of the sanitising fluid into the toilet system. The probe preferably extends forward of any nozzle on the dispenser and cartridge. Preferably, the probe is from 5 to 15 cm long.

More preferably, the probe is retractable. This is because certain, newer aircraft have a continuous suction system in the toilet base, instead of the flap described above.

For such toilets use of the probe is unnecessary, or even undesirable.

According to a second aspect, the present invention provides a liquid container cartridge for use in a liquid dispenser according to the present invention, the cartridge comprising an elongate casing having a fixed cross section, a piston at one end of the casing, and a nozzle at the other end of the casing, whereby liquid within the casing can be expelled through the nozzle upon advancing the piston within the casing towards the nozzle, and wherein the nozzle comprises a non-drip valve.

Preferably, the container is adapted to hold a toilet sanitising liquid. Here and elsewhere in this specification the term"liquid"encompasses both aqueous and nonaqueous liquids, preferably having viscosities of 1000 centipoise or less, and in any case preferably Newtonian liquids. Such conventional liquids are prone to leak from multi-use dispenser cartridges, especially under conditions of varying barometric pressure. Toilet sanitising liquids are especially prone to leak because they frequently contain solvents such as glycols and other materials which induce low surface tension.

Accordingly, the container cartridges of the present invention preferably comprise a sealing ring between the piston and an internal surface of the casing. Preferably, the sealing ring is formed from a highly viscous or waxy material, more preferably it comprises a fatty acid salt. A particularly preferred waxy material is calcium lanolinate, being the neutralisation product of wool grease and lime. Other soaps of higher fatty acids with calcium, barium, magnesium and lithium may also be used. Such sealing rings resist chemical attack by the toilet sanitising fluid and provide an effective seal throughout the dispensing process.

Preferably, the non-drip valve on the cartridge comprises a membrane of elastomeric material having one or more slits therein. More preferably, the elastomeric material comprises a silicone polymer. More preferably, the membrane is concave in its resting, closed state and inverts to a convex, open-slit shape when a threshold internal internal pressure is applied in the container to dispense liquid therefrom, only to revert to its resting, closed state upon releasing the internal pressure within the container, for example by releasing the lever of the liquid dispenser.

As already noted, the container cartridge according to the present invention preferably contains a toilet sanitising liquid. More preferably, it contains at least 500ml of such liquid, more preferably at least 800ml of such liquid. Since a typical dose required to sanitise one aircraft toilet is about 50ml, this enables ten or more toilets to be sanitised with a single cartridge without needing to reload the dispenser.

Preferably, the toilet sanitising liquid is highly concentrated, such that it comprises at least 10% by weight of one or more biocides, more preferably up to about 65% by weight of biocides such as quaternary ammonium chloride biocides. Preferably, the toilet sanitising liquid comprises from 5 to 65% of one or more polyhydric alcohols such as glycols as solvents. More preferably, the liquid comprises a highly colored dye, such as a blue dye, which acts as an indicator that a toilet has been sanitised. Likewise, the liquid preferably comprises a perfuming and/or deodorising compound.

A particularly preferred toilet sanitising liquid comprises 5-15% w/w of ethanediol, 15-30% w/w of diethylene glycol monobutyl ether, and 30-60% w/w of substituted amine biocides. A liquid of this type is commercially available from AGMA PLC of Halwhistle, United Kingdom under the Trade Mark Styx99. Styx99 is a unique combination of deodorants, reodorants, biological stabilisers, fragrance and colorants, optimised and concentrated to serve the rigorous conditions found in commercial aircraft.

Styx99 retains a strong clean blue colour even in the presence of extreme soil loadings and galley waste. It conditions the toilet or washroom with a light slightly clinical fragrance, which lasts without cloying or overpowering, even when newly charged. It also meets the requirements of WHO standards for prevention of transmission of disease by air travel and the requirements of AMS 1476B (1998) at both high and low temperatures. It contains no aldehydes or hazardous materials, is degradable and acceptable in waste water disposal. It diminishes tarring and scaling within the toilet system, and is in combination with the dispensing system of the invention clean and safe to handle, with minimal risk of leakage due to accidentally torn packaging.

In a third aspect, the present invention provides a dispenser according to the present invention having a container according to the present invention installed therein. Preferably, by providing any or all of a resilient piston, a plunger that partially retracts upon release of the plunger advancement mechanism and/or a plunger in the form of a small diameter boss, a non-drip valve provided on the nozzle can revert to its resting, closed state after expulsion of a dose of liquid from the cartridge.

In a fourth aspect, the present invention provides a method of sanitising a plurality of toilets comprising the steps of : providing a liquid container cartridge according to the present invention having a toilet sanitising liquid therein; inserting the cartridge into a dispenser according to the present invention; followed by placing the nozzle of the cartridge into a first toilet to be sanitised; followed by flexing the lever on the dispenser to dispense a predetermined amount of the sanitising liquid into the first toilet ; followed by inserting the nozzle into a second toilet without reloading the cartridge and flexing the lever to dispense a predetermined amount of the sanitising liquid into the second toilet.

Preferably, the method comprises sanitising at least ten toilets before reloading the cartridge. Preferably, the toilets are aircraft toilets.

The various features of the present invention enable the invention to be used for application of a predetermined quantity of liquid to be dispensed, in a controlled manner, into a specific position, using a hand-held and portable dispenser. The invention is especially useful for dispensing liquids under conditions of varying barometric pressure without undesired leakage.

By controlling the relative sizes of the length of plunger advancement and the cross sectional area of the container cartridge, and therefore the volume sweep of the piston within the cartridge, a specified volume of liquid can be expelled upon each full flexure of the dispenser lever. By providing a second handle, positional control of the liquid dispenser is achieved without the need to hold the front end of the liquid dispenser, which position encroaches upon the undesirable toilet environment being treated. By the provision of a safety catch, unwanted expulsion of liquid can be avoided. By juxtapositioning the handle relative to the safety catch, a convenient working position can be established for simple release of the safety catch. Left-handed, right-handed or universal versions of the liquid dispensing device can be provided.

An embodiment of the present invention shall now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a liquid dispenser according to the invention having a liquid cartridge according to the invention installed therein; Figure 2 is a detailed perspective view of the nozzle and cap region of the cartridge shown in Fig. 1; Figure 3 is a side view of the liquid dispenser shown in Fig. 1; Figure 4 is a detailed perspective view of the safety catch and handle region of the dispenser shown in Fig. 1; Figure 5 is a detailed side view of the region shown in Fig. 4, with the safety catch being held in an unlocked position; Figure 6 is a partially cut away perspective view of the liquid cartridge shown in Fig. 1 ; Figure 7 is a side view showing partial details of a ratchet mechanism; and Figure 8 is a side view of the ratchet mechanism of Fig. 7, but prior to slight retraction of the plunger.

Referring to Figure 1, there is shown a toilet sanitising liquid dispensing system 10 comprising a liquid dispenser 12 and a cartridge for the liquid 14. The liquid dispenser 12 resembles a mastic gun of the kind used in the building trade to dispense highly viscous mastic or putty, but with certain important differences as will be described further below.

The liquid dispenser 12 comprises a grip 16 and a lever 18, the lever 18 forming the trigger of the liquid dispenser 12. A plunger 20 is engageable with the lever 18 via a linkage 52 so that by flexing the lever 18 the plunger 20 will advance.

The linkage 52 has a hole through which a shaft 24 of the plunger 20 extends.

This hole is sized to allow a sliding, yet close fit of the shaft 24 within the hole. Due to the close fit, upon applying a slight bending moment to the linkage 52 so as to misalign the axes of the hole and the shaft 24, extremities of the hole will cam and engage against the shaft 24 thereby preventing movement of the shaft 24 within the hole relative to the linkage 52.

The lever 18 is attached to the linkage 52 not immediately adjacent to the hole.

Therefore, upon depressing the lever 18, a bending moment is applied to the linkage 52.

Depressing the lever 18 causes the linkage 52 to advance. Since relative movement between the shaft 24 and the linkage 52 is prevented, the plunger 20 will also advance.

The linkage 52 is biased into its retracted position (Figs. 3 and 4) by a spring.

Since the lever 18 must be released for the linkage 52 to retract, the bending moment will also be released. Therefore the linkage 52 will retract without engaging the shaft 24. In the retracted position, the hole is maintained in a state of disengagement with the shaft 24.

A plunger release mechanism 22, or non-return catch, in the form of a spring biased plate is also mounted over the shaft 24 of the plunger 20. The plate has a hole therethrough of similar size to the hole provided in the linkage 52. However, the plunger release mechanism 22 is biased by a spring into a state of engagement with the shaft 24.

The spring is coaxial with the shaft 24. Upon advancement of the shaft 24 by depressing the lever 18, the plate is released due to the forward motion of the shaft 24 causing compression of the biasing means. In this arrangement, the plate will prevent the shaft 24 and plunger 20 from being retracted or drawn out and away from a state of advancement, but will not hinder advancement of the shaft 24 and plunger 20.

The linkage 52 in combination with the plunger release mechanism and the lever 18 allow a ratchetted advancement of the plunger.

Referring now to Figures 7 and 8, there is shown an improved plunger release mechanism. In this mechanism 22, the spring 78 has been moved so that it is no longer coaxial with the shaft 24. The plunger release mechanism 22 comprises a plate 80 having a hole 84 provided therethrough. The shaft 24 extends through the hole 84. The plate 80 is loosely mounted between a flange 72 and a wall member 82 at a first end thereof, and extends substantially parallel with the handle 16. Between the handle 16 and the plate 80, towards the second end of the plate 80, the spring 78 is positioned to bias the plate 80 into its rest position, as depicted in Figure 7.

Upon advancing the shaft 24, using an advancement mechanism such as a trigger lever 18 and linkage 52, the plate 80 will advance therewith since the first end is only loosely mounted in position. A stop 74 is provided on the handle extending towards the plate 80 to restrict the available movement of the plate 80. This stop 74 may be adjustable, for example by the provision of a screw. A suitable screw is shown in Figure 5 adjacent a similar stop.

The movement of the plate 80 together with the shaft 24 results in a little free play for the plate 80 as depicted by arrow 76 in Figure 8. When the advancement mechanism is released, the spring 78 and the hole 84 will act together to allow a slight retraction of the shaft approximately corresponding to the distance depicted by the arrow 76. This distance will typically be 2mm.

The improved plunger release mechanism 22 therefore, upon release of the trigger lever 18, allows the ratchet to float backwards to provide a slight retraction. This slight retraction enables a reduction of pressure within a container of the dispenser.

In order to allow the plunger manually to be retracted or drawn out from a state of advancement, the plate is depressed slightly against its biasing force, thereby releasing the cam and engagement of the hole against the shaft 24. The shaft 24 and plunger 20 will then slide freely through both the hole of the plate and the hole of the linkage 52.

A cartridge holding receptacle 26 extends in the direction of advancement of the plunger 20. The cartridge holding receptacle 26 comprises two sides 60, a base piece 62, a back plate 64 and a forward plate 66. The two sides 60 are spaced apart to allow a cartridge 14 to fit therebetween, the cartridge 14 being supported by the base piece 62 with a nozzle 36 at the front end 38 of the cartridge 14 fitting into a slot 68 provided in the forward plate 66, and the rear end of the cartridge 14 facing the back plate 64. The two sides 60, the base piece 62, the back plate 64 and the forward plate 66 are preferably of welded steel construction forming a cradle for the cartridge 14. The cradle is secured to a fixed part 70 of the dispenser 12. Different sized cradles could be provided for different sized cartridges 14.

The receptacle 26 is adapted to hold a specific type of cartridge 14. The different types of cartridge 14 may have different sections and/or diameters so that specific volumes of liquid contained therein will be correctly expelled upon full flexure of the lever. In the embodiment shown, the cartridge 14 is cylindrical having an internal diameter of approximately 8.5cm. The advancement length of the plunger per full flexure of the lever is approximately 1.13cm to achieve a 50ml dose of liquid from inside the cartridge.

A probe 28, shown extended in Figure 1, is provided on the cartridge holding receptacle 26 on one of the sides 60 thereof. The probe 28 is a length of metal, rotatably secured onto a bolt on the cartridge holding receptacle 26 by a butterfly nut 30. Two holes 32 are provided through the probe 28 equidistant from the nut for engaging a peg 34, also provided on the cartridge holding receptacle 26, for locating the probe 28 either in its extended or its retracted position.

The cartridge 14 has a nozzle 36 provided on its front or forward liquid expulsion end 38. The nozzle has a flip top cap 40 and a non-drip valve 42, as shown in more detail in Figure 2. The valve 42 in Fig. 2 is shown in the open, liquid-dispensing position. The valve comprises a membrane of silicone elastomer having a cross-cut therein. In its resting (closed) position, the membrane is concave when viewed from outside the cartridge and the cross-cut is closed and resists leakage of liquid from inside the cartridge. However, when a predetermined threshold pressure inside the cartridge is exceeded, the membrane inverts to a convex shape as shown in Fig. 2, thereby opening up the cross-cut to allow liquid to pass freely out of the nozzle.

Figure 3 shows the liquid dispenser 12 with the cartridge 14 removed and the probe 28 fully (solid line) and partially (broken line) retracted. The liquid dispenser 12 is fitted with a safety catch 46 and a handle 48. These can be seen more clearly in Figures 4 and 5.

Figure 4 shows the safety catch 46 biased by spring 50 into a locking position. In the locking position, the catch 46 fits between the linkage 52 and the fixed part 70 of the liquid dispenser 12. The locking position prevents advancement of the plunger 20 since the linkage 52 itself will not advance. To unlock the safety catch 46, a user must release the catch 46 against the bias of the spring 50 into the position shown in Figure 5. The handle 48 is juxtapositioned relative to the safety catch 46 to allow a user to use his thumb to release the safety catch 46. In the unlocked position, the linkage 52 is free to advance into the position shown in Figure 5, thereby advancing the plunger 20.

Referring now to Figure 6, the cartridge 14 comprises a cylindrical wall 58 and a piston 56 slidably received in sealing engagement inside the cartridge 14.. The novel sealing ring 54 provides a seal against liquid creep out of the cartridge 14 between the internal wall 58 and the piston 56 of the cartridge 14. The sealing ring 54 is formed from a generally waxy product having high resistance to toilet sanitising chemicals.

Preferably, the sealing ring is formed from a fatty acid salt, such as calcium lanolinate. In use, the sealing ring adheres and spreads on the inner wall of the cylinder 58 and prevents leakage much more effectively than conventional elastomeric 0-rings.

The steps involved in the loading of a liquid dispenser with a cartridge in accordance with the present invention and then the application of the liquid to a toilet bowl in an aircraft involve: 1. Lightly depressing the piston release mechanism 22 whilst holding the cartridge free liquid dispenser 12.

2. Drawing out the piston 20 and shaft 24 to its maximum extension to provide access to the cartridge holding portion 26 for a cartridge 14 to be inserted therein.

3. Placing a cartridge 14 in the cartridge holding portion 26 with the plunger 20 and the piston 56 facing each other and with the nozzle cap 36 extending in the direction of advancement of the plunger 20.

4. Holding the liquid dispenser 12 in both hands with the fixed handle 16 and lever 18 in the right hand, and the second handle 48 in the left hand, releasing the safety catch 46 and gently tightening the plunger 20 onto the piston 56 of the cartridge 14 using the lever 18. Care should be taken to avoid spillage of liquid due to over advancing the plunger 20 so as actually to drive the piston 56 inside the cartridge 14.

5. Opening the flip top cap 40 of the nozzle 36.

6. Using the probe 28 to depress a toilet flap.

7. Whilst depressing the safety latch 46, squeezing the lever 18 one full flexure to dispense a single dose of 50ml of the toilet additive into the toilet bowl and then releasing both the lever 18 and the safety catch 46.

8. Finally, optionally, closing the flip top cap 40 on the nozzle 36.

The above embodiment of the present invention has been described above purely by way of example. It should be noted that modifications of detail may be made by the skilled person within the scope of the invention as defined in the accompanying claims.

Claims

CLAIMS 1. A liquid dispenser for expelling predetermined doses of liquid from a cartridge, said dispenser comprising: a cartridge holding receptacle, a lever capable of flexure up to a predetermined maximum extent and a plunger, wherein the lever is coupled to the plunger such that flexure of the lever to the said maximum extent advances the plunger a predetermined distance into the receptacle.
2. A liquid dispenser according to claim 1, wherein the liquid dispenser further comprises a pistol-type grip extending sideways from the dispenser.
3 A liquid dispenser according to claim 2, wherein the lever extends obliquely adjacent to the grip, whereby flexure of the lever to operate the dispenser can be achieved by squeezing the lever and the grip together with one hand.
4. A liquid dispenser according to claim 2 or 3, further comprising a handle located opposite said grip.
5. A liquid dispenser according to any preceding claim, comprising ratchet means to return the lever to a starting position following flexure of the lever without substantial displacement of the plunger, whereby the plunger can be advanced through the receptacle stepwise by repeated flexure of the lever.
6. A liquid dispenser according to any preceding claim, wherein the dispenser further comprises biasing means to return the lever to a starting position following flexure of the lever.
7. A liquid dispenser according to claim 5 or 6, wherein the ratchet means also allows a slight retraction of the plunger upon release of the lever.
8. A liquid dispenser according to claim 7, wherein the ratchet means comprises a linkage biased into light engagement with a shaft of the plunger by a spring, so that upon release of the lever, the slight retraction of the plunger is effected.
9. A liquid dispenser according to any preceding claim, wherein the plunger comprises a small diameter boss for driving a piston of a cartridge provided in the cartridge holding receptacle.
10. A liquid dispenser according to any preceding claim, wherein said predetermined distance is less than 20% of the length of said receptacle.
11. A liquid dispenser according to any preceding claim, wherein said predetermined distance is less than 10% of the length of said receptacle.
12. A liquid dispenser according to any preceding claim, wherein the liquid dispenser further comprises a safety catch to prevent inadvertent operation of the dispenser.
13. A liquid dispenser according to claim 12, wherein the safety catch is biased into a locking position at which it prevents inadvertent operation of the dispenser.
14. The liquid dispenser of claim 12 or 13, wherein the safety catch is juxtapositionned with a handle or grip of the dispenser so that in use a hand of an operator grasping the handle or grip is positioned to operate the safety catch whilst still grasping the handle or grip.
15. A liquid dispenser according to any preceding claim, wherein the liquid dispenser further comprises a probe projecting from a forward end of the receptacle.
16. A liquid dispenser according to claim 15, wherein the probe is from 5 to 15 cm long.
17. A liquid dispenser according to claim 15 or 16, wherein the probe is retractable.
18. A liquid dispenser substantially as hereinbefore described with reference to the accompanying drawings.
19. A liquid container cartridge for use in a liquid dispenser according to the present invention, the cartridge comprising an elongate casing having a fixed cross section, a piston at one end of the casing, and a nozzle at the other end of the casing, whereby liquid within the casing can be expelled through the nozzle upon advancing the piston within the casing towards the nozzle, and wherein the nozzle comprises a non-drip valve.
20. A liquid container cartridge according to claim 19, wherein at least a part of the piston is resiliently deformable from a convex dispensing configuration to a concave resting configuration.
21. A liquid container cartridge according to claim 19 or 20, wherein a sealing ring is provided between the cylinder and an internal surface of the casing.
22. A liquid container cartridge according to claim 19,20 or 21, wherein the sealing ring is formed from a waxy material.
23. A liquid container cartridge according to claim 22, wherein the sealing ring comprises a fatty acid salt.
24. A liquid container cartridge according to claim 23, wherein the sealing ring comprises calcium lanolinate.
25. A liquid container cartridge according to any of claims 19 to 24, wherein the nondrip valve comprises a membrane of elastomeric material having one or more slits therein and a cap.
26. A liquid container cartridge according to claim 25, wherein the elastomeric material comprises a silicone polymer.
27. A liquid container cartridge substantially as hereinbefore described with reference to the accompanying drawings.
28. A liquid container cartridge according to any one of claims 19 to 27 containing therein a toilet sanitising liquid.
29. A liquid container cartridge according to claim 28, wherein the toilet sanitising liquid comprises at least 10% by weight of one or more biocides.
30. A liquid container cartridge according to claim 29, wherein the toilet sanitising liquid comprises from 5 to 65% of one or more glycols and from 10 to 65% of one or more biocides.
31. A liquid container cartridge substantially as hereinbefore described with reference to the accompanying Figures 1,2 and 6.
32. A liquid dispenser according to any one of claims 1 to 18, in combination with a liquid container cartridge according to any one of claims 19 to 31.
33. A method of sanitising a plurality of toilets comprising the steps of : providing a liquid container cartridge according to any one of claims 19 to 31 having a toilet sanitising liquid therein; inserting the cartridge into a dispenser according to any one of claims 1 to 18; followed by placing the nozzle of the cartridge into a first toilet to be sanitised; followed by flexing the lever on the dispenser to dispense a predetermined amount of the sanitising liquid into the first toilet; followed by inserting the nozzle into a second toilet without reloading the cartridge and flexing the lever to dispense a predetermined amount of the sanitising liquid into the second toilet.
34. A method according to claim 33, wherein at least ten toilets are sanitised without reloading the cartridge.
35. A method according to claim 33 or 34, wherein the toilets are aircraft toilets.