Liquid purification or separation – Flow – fluid pressure or material level – responsive
Reexamination Certificate
2002-06-21
2004-11-23
Prince, Fred G. (Department: 1724)
Liquid purification or separation
Flow, fluid pressure or material level, responsive
C210S181000, C210S184000, C210S259000, C210S416300
Reexamination Certificate
active
06821414
ABSTRACT:
This invention relates to water treatment and is particularly concerned to provide a means of purifying water in an apparatus suitable for use in a post-mix beverage dispenser, although it will be appreciated that water treated according to the invention may be used for other purposes.
Water quality and purity vary considerably from location to location and it is an object of the invention to provide a means whereby the water to be used in a post-mix dispenser or for other use can be rendered of the desired quality and purity using a relatively simple to operate and renewable means.
To be suitable for use in beverages water should not have excessive bicarbonate, carbonate and organic matter. Chlorine and heavy metals may also need to be removed.
It is also an object of the invention to provide an improved water treatment device in which blockage of water flow through the device by the necessary precipitation of the unwanted impurities can be ameliorated.
It is known from U.S. Pat. No. 4,844,796 to provide a water treatment apparatus for post-mix beverage dispensers in which the water to be treated is passed into a removable disposable cartridge having a first, reactor section and a second, filter section wherein the water is heated in the reactor section firstly by passing through a heat exchanger and secondly by means of a heater. The heater is positioned in a central aperture defined by an annular portion of the cartridge whereby it does not come into direct contact with the water.
A similar heater arrangement is disclosed in U.S. Pat. No. 5,858,248 where the heater can be located in the central cavity of a disposable cartridge of a water treatment device. Alternative heater arrangements disclosed in this application are to position the heater around the outer cylindrical surface of the cartridge or to have a gas cylinder heater beneath a central “chimney”, i.e. the central cavity defined by the annular portion of the cartridge.
In all these heater embodiments, the beater is kept separated from the water under treatment. It does not become covered in deposits of the precipitated impurities that come out of solution in the water during the heating and sieving stages that take place in the cartridge. Thus the heaters are reusable and not disposed of with the disposable cartridges.
We have now surprisingly found that an efficient and economic water purification means may be achieved without the need to separate the heater from the water under treatment and hence without the need for the heater to have a long built-in life expectancy.
Accordingly, in one aspect the invention provides a water treatment apparatus comprising a treatment housing having an inlet for the water to be treated, an outlet for the treated water, a heater within the housing to come into direct contact with the water and a filter between the heater and the outlet, and means to fill the housing with water up to a maximum level which leaves a headspace between the water and the roof of the housing, the entrance to the outlet being below the operating water level.
Preferably the inlet is arranged so that the water travels upwardly within the housing.
Conveniently, the housing is in the form of a disposable cartridge which may be dispensed with, including its heater, when its life expectancy is reached.
The cartridge may contain one or more perforated screens or meshes between the beater and the filter but this is not essential.
Thus in one preferred embodiment the apparatus comprises a cylindrical housing having an inlet for the water to be treated, a heater spaced above the base of the housing and, extending within the cylindrical housing, one or more perforated screen(s) above the heater, a filter above the screen(s) and an outlet for the treated water above the filter. The outlet may conveniently be through the closed upper end of the cylinder.
The outlet extends beneath the level of the water so that hot water leaves the treatment housing without going through the headspace. Steam and volatiles collect in the headspace and may be allowed to escape through a pressure relief valve, as is described in more detail below.
The unfiltered water, e.g. from the mains, may first pass through a heat exchanger to warm it before it passes into the housing. Treated heated water leaving the housing may be passed in the opposite direction through the heat exchanger to act as the heat exchange medium to warm the incoming mains water. The treated water is, thereby, conveniently cooled before being passed to a reservoir or for direct use.
In another preferred embodiment the heat exchanger and the water treatment housing may be contained in a single unit, preferably with the heat exchanger directly beneath the water treatment housing. This may be a unitary structure or two separate units, water treatment housing and heat exchanger, which may be completely or partially disposable. For example, the water treatment housing may be a disposable cartridge and the heat exchanger non-disposable.
This single unit arrangement has the advantage that pipework between the heat exchanger and the water treatment housing can be considerably reduced, if not eliminated. The heated water from the heat exchanger may pass directly into the water treatment housing and the treated water from the housing can pass directly back to the coils of the heat exchanger in order to heat the incoming water. This arrangement reduces the regions where precipitation deposits may build up and harmfully affect water flow. Also, with the heat exchanger directly below the water treatment housing, the inlet to the water treatment housing can readily enter at its cooler, lower end.
The inlet for the water to be treated may conveniently enter through the floor of the treatment housing but this is not essential. For example, in some embodiments the water to be treated may enter the housing through a pipe entering the housing through or near the roof, which pipe extends downwardly inside the housing towards its base. On leaving the pipe water, once the hosing is filled to the lower end of the pipe, will then travel upwardly.
In another aspect the invention provides a water treatment apparatus comprising a treatment housing and a heat exchanger, the treatment housing having an inlet for the water to be treated, an outlet for the treated water, a heater within the housing and a filter between the heater and the outlets the inlet to the treatment housing receiving water that has passed from a source of untreated water through the heat exchanger and the outlet from the treatment housing passing treated water back through the heat exchanger, and a bypass valve to close the heat exchanger to incoming untreated water and to allow the incoming untreated water to flow directly into the treatment housing, whereby the hot treated water passing through the heat exchanger sterilises the heat exchanger.
The bypass valve means may conveniently be a first valve on the inlet pipe to the heat exchanger which is open during normal operation to allow inflow of untreated water, e.g. mains water, and a bypass valve in a bypass pipe between the source of untreated water and the first valve. The bypass valve is closed during normal operation. In sterilisation mode, the first valve is closed and the bypass valve is opened, thereby allowing water into the bypass pipe which takes the untreated water directly into the treatment housing inlet.
This sterilisation arrangement may be used with side by side separate units, or single units, which may be used one above the other as described above, and with housings having heaters which may or may not be in direct contact with a the water.
Where the water treatment housing and the heat exchanger are housed side by side rather than one beneath the other, their upper ends may conveniently be closed by an appropriately shaped and gasketted single plate, e.g. of steel. The necessary pipework for the required water flows into and out of the two housings can then pass through appropriately sized and gasketted holes in the plate. However, in another embodiment t
Johnson Martin Stanley
Wiemer Klaus
Williams Graham
Prince Fred G.
Sutherland & Asbill & Brennan LLP
The Coca-Cola Company
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