An existing method of introducing de-scaling fluid into a central heating system involves injecting the de- scaling fluid into an air valve of a radiator of the central heating system. The fluid is pumped manually into the radiator from a container in which the fluid is supplied.

Disadvantages arise with the above method because it requires the removal of the radiator air valve which can lead to fluid in the radiator system leaking from the radiator. Also, the de-scaling fluid often remains in a concentrated form in the radiator and doesn't spread around the central heating system, as is intended.

It is an object of the present invention to address the above mentioned disadvantages.

According to one aspect of the present invention a fluid introduction device for introducing primary and secondary fluids into apparatus having a closed fluid- containing section comprises a primary fluid input portion for receiving said primary fluid, a secondary fluid input portion for receiving said secondary fluid, mixing means

for mixing said primary and secondary fluids and an output portion, whereby, in use, said second fluid is drawn into the device by a flow of the primary fluid through the device.

The primary fluid may be water.

The secondary fluid may be a cleaning fluid, such as a de-scaling fluid.

The apparatus may be a central heating boiler or a central heating system. Alternatively the apparatus may be a washing machine or a dishwasher or an underfloor heating system.

The primary fluid input portion may comprise an opening which may be operable to have a supply means for the primary fluid secured thereto, which supply means may be a conduit or hose. The supply means may be arranged to deliver the primary fluid to the device.

The secondary fluid input portion may comprise an opening which may be operable to have a supply means for the secondary fluid secured thereto. The supply means may be a conduit or a container. The supply means may be arranged to deliver the secondary fluid to the device.

The supply means may be a pressurised container, which may contain the secondary fluid in a pressurised state.

The mixing means may comprise at least one channel in a body portion of the device. Said channel may be operable to direct said primary fluid into said secondary fluid input portion.

The mixing means may comprise a plurality of channels, which may link the primary and secondary input portions to the output means, which output means may include a single channel.

The output means may include a non-return valve.

The mixing means may comprise a channel extending from the primary input portion to the secondary input portion. The mixing means may comprise a channel extending from the secondary input portion to the adjustment portion. The mixing means may comprise a channel extending from the adjustment portion to the output portion.

The mixing means may be operable to adjust the mixing of the fluids. The mixing means may comprise an adjustment portion, which may effect said adjustment.

The adjustment portion may comprise a channel blocking member which is operable to selectively block a channel of the mixing means or to leave said channel unblocked. The blocking may be a partial blocking.

The channel blocking member may be a pin, which may be biased to maintain the channel in an unblocked state.

The bias may derive from a spring. The channel blocking member may be adjusted by a control member of the adjustment portion. The control member may be mounted on a body portion of the introduction device by a screw thread, and may be adjustable by means of being turned, to bear down on said channel blocking member or to relieve pressure thereon, depending on the sense of said turning.

The invention extends to apparatus having a closed fluid-containing section with a fluid introduction device as described above attached thereto.

According to another aspect of the present invention, a method of introducing a secondary fluid into apparatus having a closed fluid-containing section comprises a fluid introduction device receiving a primary fluid in a primary fluid input portion thereof, receiving said secondary fluid in a secondary fluid input portion of the device, mixing said primary and secondary fluids in a mixing means of the device and outputting the mixed fluids from an output portion of the device, whereby the secondary fluid is drawn into the device by a flow of the primary fluid through the device.

The method may be a method of introducing a cleaning fluid into a central heating system, dishwasher, washing machine, underfloor heating system or the like.

The method may include the device including mixing means, which may be adjustable to alter the mixing of the primary and secondary fluids.

The mixing may involve passing the primary fluid into the secondary fluid input portion.

The mixing may involve passing the fluids through a number of channels of the mixing means.

The invention extends to a method of cleaning apparatus having a closed fluid-containing section.

According to a further aspect of the present invention, a fluid introduction device, for introducing a

secondary fluid into apparatus having a primary fluid containing section, comprises supply means operable to supply the secondary fluid under pressure to an output portion of the device, which output portion is adapted to be secured to a primary fluid port of the apparatus.

The primary fluid may be water. The secondary fluid may be a maintenance fluid, such as a cleaning fluid.

The primary fluid containing section may be a fluid circulation heating system, which may be of the sealed or unsealed type.

The secondary fluid may be contained in a pressurised state in a container of the supply means. The container may be a pressurised container, which may be an aerosol container.

The primary fluid port may be a fluid inlet. Where the primary fluid containing section is an unsealed fluid circulation heating system, the port is preferably a primary fluid output port.

According to a still further aspect of the invention a method of introducing a secondary fluid into an apparatus having a primary fluid containing section comprises providing a fluid introduction device with supply means and supplying the secondary fluid under pressure from the supply means to an output portion of the device, the output portion supplying the secondary liquid to a primary fluid port of the apparatus.

The primary fluid port may be a fluid inlet, or alternatively may be a fluid outlet.

Any of the features disclosed herein may be combined with any of the above aspects, in any combination.

A specific embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic partial cross-section through a cleaning fluid introduction device with a bottle of cleaning fluid secured thereto; Figure 2 is a schematic side view of the device shown in figure 1 in use; Figure 3 is a schematic cross-sectional view of a body portion of the device; and Figure 4 is a schematic cross-sectional view of an alternative embodiment of a cleaning fluid introduction device.

A cleaning fluid introduction device 10 comprises a hose portion 12 and a body portion 14. The body portion 14 comprises a flow adjuster 16, a bottle attachment section 18, and a hose receiving section 20. The device is arranged to be secured between the inlet water tap 22 (see Figure 2) and boiler inlet 24 of a central heating system or the like. Water which passes from the tap 22 through the body portion 14 of the device 10 draws cleaning fluid from a bottle 26 secured to the device 10, which fluid then flows with the water from the tap into the boiler 42 and the central heating system beyond. The device is particularly suitable for sealed systems, which typically have a combination boiler, rather than a boiler and header tank.

The body portion 14 is made of brass. The hose receiving section 20 has a cylindrical cross section. It is externally threaded, to receive a captive nut 30 (see Figure 3) of a boiler hose 28 thereon and is sized to receive a spigot of the boiler hose 28 within its cylindrical cross section.

The hose portion 12 of the device 10 is secured to the body portion 14 in the same way.

The body portion 14 incorporates a channel 32 which extends between the hose receiving section 20 and the bottle attachment section 18. A further channel 34 extends from the bottle attachment section 18 to the flow adjuster 16, with a still further channel 36 extending from the flow adjuster 16 into the hose 12.

The flow adjuster 16 comprises a tapered nut 38 which is received in a tapered chamber 47 in the channel 36 and is sized to fit snugly in the tapered chamber 47. The nut 38 is retained in the chamber by a cap 44. The nut 38 is biased with a spring 48 to keep the channel 36 open. A threaded knob 40 is mounted so that screwing the knob 40 into the body portion 14 pushes against a pin 46 which protrudes through the cap 44 to exert pressure on the nut 38 to gradually close the channel 36. Unscrewing the knob 40 will result in the pin 46 releasing the nut 38 thus gradually opening the channel 36. A flow of fluid through the channel 36 can thus be adjusted by turning the threaded knob 40 to adjust the position of the nut 38 in the chamber 47.

The bottle attachment section 18 has a cylindrical cross section and is internally threaded to receive a

correspondingly externally threaded bottle 26, or the like.

In use, the boiler hose 28 is detached from its boiler 42 and secured to the hose receiving section 20.

The free end of the hose portion 12 of the cleaning fluid introduction device 10 is then secured to the boiler inlet 24 which has been freed for use. A bottle 26 of cleaning fluid is screwed into the bottle attachment section 18.

The tap 22 of the central heating system is then opened which allows fluid to flow along the hose 28 to the cleaning fluid introduction device 10. If the flow adjuster 16 has been adjusted to close the channel 36 then water from the tap will only proceed to the top of the channel 36. If however, the channel 36 is open or partially open then the water passing through the bottle attachment section 18 will draw cleaning fluid from the bottle to pass with the water up the channel 34, through the flow adjuster 16 and down the channel 36 to the hose portion 12 and through into the central heating system.

If it is desired to adjust the uptake of cleaning fluid from the bottle 26 then adjustment of the threaded knob 40 can be made to either increase or decrease the flow, as required.

When sufficient cleaning fluid has been introduced into the central heating system, the tap 22 is turned off and the cleaning fluid introduction device 10 is then removed from the boiler so that the boiler hose 28 can be reconnected to the boiler 42.

Alternatively, the device may remain attached to the boiler system, for continuous or occasional introduction of cleaning fluid or the like.

The device may have a non-return valve (not shown) on the outlet channel 36.

The device may be provided without a flow adjuster for simplicity and cheapness.

Another embodiment of fluid introduction device 10 is shown in figure 4. This embodiment has a number of features in common with the previous embodiment, which features have like numerals.

This embodiment differs in that the hose receiving section 20 is replaced by a cut-off valve 60 and the bottle 26 is replaced by a pressurised canister 62 containing the cleaning fluid. The canister 62 may be of a standard aerosol type, typically used to contain butane gas and the like. The cut off valve 60 is provided to cut-off the supply of cleaning fluid from the canister 62 when the device is not in use. The flow adjuster 16 also acts as a pressure valve in this embodiment.

The previous embodiment may be modified by the addition, by welding, of a plate (not shown) to the bottle attachment section 18. The plate may have an internally threaded opening to receive a corresponding thread of the pressurised canister 62. The plate would allow retrofitting to allow the previous embodiment to be used with this embodiment.

This embodiment may be used with unsealed heating systems (which have a conventional boiler and header tank) as well as sealed heating systems (which have a combination boiler).

In use, the cleaning fluid is fed to the flow adjuster 16 from the canister 62 through the channel 34 with the cut-off valve 60 in an open position. The cleaning fluid is forced through the device by virtue of it being pressurised. The fluid is then fed into the system, most conveniently through the drain cock of the heating system, which is usually at the lowest point thereof.

The flow adjuster 16 is modified slightly by the addition of O-rings where there would be metal on metal contact, to account for and prevent leaks of gas with which the cleaning fluid is pressurised.

An advantage of this particular embodiment is that a flow of water is not needed to introduce the fluid in the system; this is achieved by the pressurised fluid itself.

The introduction of fluid with either embodiment may be effected automatically, by means of a timer device or by use of a detector, such as a pH detector which triggers the device when a particular pH is reached.

The cleaning fluid introduction devices described above may also be used with other devices and systems including a fluid containing section, such as washing machines, dishwashers, cooling towers and under floor heating.

The above described cleaning fluid introduction devices allow a precise dosage of fluid to be introduced into the system or device chosen.

As well as de-scaling fluid, other fluids can be introduced into the systems and devices mentioned above.

Such fluids may be cleaning fluids.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.