Note: Descriptions are shown in the official language in which they were submitted.
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
1
SHOWER BASE
FIELD OF THE INVENTION
The present invention relates to a base structure for use in shower cubicles.
In
particular, the invention provides a shower base for use in showers that use
water recirculation to save water.
BACKGROUND TO THE INVENTION
The issue of water conservation is becoming increasingly important given the
effects of population and climate change on the world's water supplies.
Significant volumes of water are wasted in the bathroom where many liters are
sent to waste in the course of bathing and showering. While a shower is often
considered to be less wasteful of water than a bath, this assumption may be
valid only where the shower is of short duration. Many people enjoy the
relaxing effects of a shower, and can often spend significant periods of time
under running water. Many also attend to other tasks such as dental care,
exfoliation, depilation and the like during showering. The extended time spent
in the shower leads to wastage of significant amounts of water.
In an effort to limit the amount of water used in a shower, the prior art
includes
a number of shower systems including means for recirculation of water
between the drain and the shower head. Typically, when in recirculation mode
a valve positioned between the drain hole and sewer is closed (or the drain
itself is closed), and a pump is used to extract water falling on the floor of
the
cubicle and direct it to the shower head for reapplication to the user. When
the
shower is in recirculation mode, input of mains water is not required and the
user is able to remain under the shower for as long as desired without the
further wastage of water.
While recirculation shower apparatuses can save water, many are still wasteful
of the resource. One apparatus known in the art is the Kohler BodySpa
system (Kohler Co, WI, U.S.A.). The Kohler system includes a tub in which the
user stands, a recirculation pump that extracts water from the tub and directs
it
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
2
back to the user via a number of jets. While this system saves water when in
recirculation mode, it requires a large volume of water in the system before
the
recirculation pump can be started. The tub must be filled to a level of around
150 mm, this equating to around 130 to 140 liters of water. A further problem
with this and similar systems is that when in recirculation mode the user is
forced to stand in a pool of water. This is unpleasant for the user, with the
vast
majority preferring the more familiar experience of a standard shower whereby
water is drained away from the feet and lower legs. Relevant to the issue of
water temperature the larger volume of recirculation water (having a
commensurately large surface area) creates difficulties in maintaining a
comfortable water temperature.
Other types of recirculation showers include a tank and a recirculation pump,
these components being located under the floor of the shower base. In
recirculation mode, water falling on the floor of the shower base runs into
the
drain but is diverted into a tank. A recirculation pump then extracts water
from
the tank, directing it to the shower head. This arrangement has a number of
problems, one being that a shower base of increased height is necessary to
accommodate components under the floor. It may therefore be difficult for
persons having mobility issues to safely enter the shower. A high shower base
is also aesthetically undesirable. Furthermore, having components under the
floor makes maintenance and cleaning difficult.
Another problem with this design is that the recirculation water passes
through
the drain hole in the floor of the shower base. From the drain hole, the water
then enters a separate tank for recirculation to the shower head. Users find
the idea of being exposed to water that has entered a drain hole unsavory, and
for good reason. Drain holes are known to be repositories for dirt and
bacteria,
this leading to the probable contamination of water passing through a drain.
Given the closed nature of tank-based designs, it is also readily apparent
that
cleaning designs such as these also have the problem that the drain to waste
is typically attached to the tank, this leading to access difficulties where
the
drain becomes blocked.
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
3
It is an aspect of the present invention to overcome or alleviate a problem of
the prior art by providing a shower base that, when used in the context of a
recirculation shower system, can reduce water requirements, is "slimline" and
has easy access to components for the performance of hygienic maintenance.
A reference herein to a patent document or other matter which is given as
prior
art is not to be taken as an admission that that document or matter was, in
Australia, known or that the information it contains was part of the common
general knowledge as at the priority date of any of the claims.
SUMMARY OF THE INVENTION
In one aspect the present invention provides a base structure for a shower
having a water recirculation circuit, the base including a substantially
planar
floor and a reservoir, the reservoir including a first outlet for admitting
water to
be used by the recirculation circuit, and a second outlet for admitting water
to
be sent to waste, wherein where the passage of water to waste is obstructed,
water contacting the floor runs into the reservoir to form a pool of
sufficient
depth to substantially cover the first outlet.
Applicant proposes that the use of a reservoir minimizes the amount of water
required to be used in a recirculation shower apparatus. As will be
understood, to start water moving through a recirculation circuit a minimum
level of water must be available to the system. The minimum volume includes
water necessary to fill all components of the circuit (for example pipes,
valves,
fittings, pumps etc), and also water necessary to ensure that the intake to
the
recirculation pump is covered with water. It is necessary to ensure that
sufficient water is available to the intake side of the pump such that air, or
at
least a significant volume of air, is not drawn into the system. The presence
of
air can lead to cavitation in the pump causing complete cessation of water
flow
in the recirculation circuit. The presence of a reservoir about the first
outlet
means that only a small volume of water is necessary to cover the outlet,
thereby decreasing the minimum volume of water required to run the shower in
recirculation mode.
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
4
In operation, when the shower is in recirculation mode water from the shower
head falls onto the floor of the shower base. The water then enters the
reservoir where it pools because the drain outlet is closed. As the water
level
in the reservoir increases, the first outlet becomes submerged, ensuring that
the pump intake is covered in water. Once the inlet is covered, the pump may
then be safely operated. Thus, the reservoir acts to cover the intake with as
small amount of water as possible such that the pump is able to still operate
without sucking air.
In one form of the invention, the reservoir extends around at least a portion
of
the substantially planar floor. Alternatively, the substantially planar floor
extends around the reservoir. In both these embodiments, to assist in the
movement of water from the floor to the reservoir, the substantially planar
surface is sloped such that water runs under the force of gravity into the
reservoir.
Alternatively, to increase the efficiency of water collection from the floor
the
reservoir may extend distal to the first outlet. In one embodiment, the
reservoir
extends along one or more edges of the shower base. In this embodiment, the
water may run into areas of the reservoir distal to the first outlet, but then
further run to an area of the reservoir proximal to the first outlet.
The shape or dimensions of the reservoir can be altered according to the
specific requirements of any given application. Of course, in order to
minimize
the volume of water used to operate the shower in recirculation mode, a
reservoir of small volume is preferred. In one embodiment, the reservoir holds
about 30 liters of water or less. In another embodiment, the reservoir holds
about 15 liters of water or less. In yet a further embodiment the reservoir
holds
about 10 liters or less. When selecting an appropriate depth for the
reservoir,
consideration must be given to the depth required to cover the first inlet. In
one embodiment, the depth is about 100 mm or less. In another embodiment
the depth is about 50 mm or less. Where the reservoir is of variable depth,
these figures refer to the deepest region of the reservoir.
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
The floor and reservoir may be arranged in any way relative to each other such
that water contacting the floor is able to run into the reservoir. Typically,
this is
achieved by arranging the floor so that the surface is substantially
continuous
with the upper edge of the reservoir. In this arrangement, water runs under
the
5 force of gravity from the surface of the floor into the reservoir. This
arrangement is facilitated by manufacturing the shower base in unitary form.
It will be understood that the term "a base structure for a shower" includes
an
arrangement whereby a shower is positioned above a bath tub, and water from
the shower collects on the floor of the bath tub. In this form of the
invention,
the reservoir is included in the floor of the bath tub. The term also includes
the
floor of a shower room, typical of those found in public facilities such as
gymnasiums, swimming pools and the like. In this form of the invention, the
reservoir is included in the floor of the shower room.
In one form of the invention the first outlet is positioned in the reservoir
such
that water passes through the outlet in a non-vertical direction. Preferably,
the
first outlet is positioned such that water passes through the outlet in a
substantially horizontal direction. This may be achieved by positioning the
outlet on a substantially vertical wall of the reservoir. As discussed in the
Background section, consumers are averse to being exposed to water that has
entered a standard drain in the floor of a shower base. The use of a reservoir
having an outlet on a substantially horizontal wall feeding the recirculation
pump allows the user to assure them that the recirculating water enters only
the inlet that feeds the recirculation pump and does not enter the drain.
Furthermore, the horizontal exit of water provides the user confidence that
water used for recirculation does not pool, as may be the case where the water
exits vertically as occurs with a traditional drain hole in the floor of a
shower
base.
Users also dislike the tank-based designs of the prior art because of the
inability to properly clean the tank. Accordingly, in another form of the
invention, the reservoir is an open reservoir, as distinct from a reservoir
that is
closed, such as a tank.
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
6
It is emphasized that the water does not need to exit the reservoir exactly
horizontally. So long as the water exits the reservoir in a non-vertical
manner,
the problem of water pooling will not result. The user will therefore not be
left
with the impression they are being exposed to contaminated water, such as
that from a standard drain where water exits in a vertical direction.
It is further emphasized that the water does not need to maintain a horizontal
flow for the entire distance between the first inlet and the recirculation
pump.
Indeed, in a preferred form of the invention there is a slight "fall" in the
piping
used to connect the pump and the reservoir such that water does not pool. Of
course, the fall could be such that water runs to the pump (from which it
subsequently drains), or indeed any other low point in the system.
The reservoir includes a second outlet to admit water to the drain, the outlet
being operable between an open and closed state. In one form of the
invention the second outlet is closed with a simple plug that is mounted on a
spindle permanently affixed to the outlet. The plug is moveable along the
spindle such that when it is distal to the outlet, water can enter the drain,
and
when in contact with the outlet the outlet is sealed. It is contemplated that
the
outlet can be moved from the open state to the closed state simply by the foot
stepping on the plug. In one form of the invention the plug includes an
overflow protection device such that the reservoir is not able to fill above a
predetermined level. This is useful to prevent overflow of water from the
shower base into the bathroom, and also for preventing overflow of water from
the reservoir to the floor of the shower base. This latter use avoids the
situation where the user is left standing in a pool of water if the mixer
valve is
closed too late after the shower is placed into recirculation mode, and excess
water from the mains enters the system. One overflow protection device
consists of an upright, hollow tube that extends upwards and through the plug,
terminating above the plug at the maximum fill level of the reservoir. Thus,
when the plug is closed and the water rises to the maximum fill level of the
reservoir, any excess water entering the system runs down the hollow tube
and to waste.
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
7
In another aspect the present invention provides a recirculation shower system
including a shower base as described herein and a recirculation pump, the
first
outlet of the shower bases being connected to the recirculation pump such that
in use water flows from the first outlet to the recirculation pump. In one
form of
the system, the water flows substantially horizontally from the first outlet
of the
shower base to the inlet of the recirculation pump. In another form of the
invention the system is capable of operating on a volume of less than about 30
liters of water or less. In another embodiment, the system is capable of
operating on about 15 liters of water or less. In yet a further embodiment the
system is capable of operating on about 10 liters or less. Further savings in
water usage will be obtained where small diameter pipes are used such that
the minimum volume of water required for recirculation is lessened. In one
form of the invention, pipes of a diameter of about 35 mm or less are used. In
another form of the invention the pipes of a diameter of about 15 mm or less.
A smaller diameter pipe used to convey water from the first inlet will also
mean
that a lower level of water is necessary in the reservoir to fully cover the
inlet.
In another aspect, the present invention provides a kit of parts for assembly
into a recirculation shower system as described herein, the kit including a
base
as described herein and a recirculation pump.
The present invention may provide advantages in respect to decreasing
energy requirements for heating water used in showering. When in
recirculation mode, further water is not admitted to the circuit, with water
collected from the reservoir providing all water necessary to supply the
shower
head. In this embodiment of the invention, it is therefore not necessary to
heat
water from ambient temperature, to a temperature comfortable for showering.
It will be appreciated that increased advantage may be gained where the
ambient temperature is low (for example, 2 or 3 degrees Celsius) in which
situation large amounts of energy are required to heat water up to a
temperature comfortable for showering.
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
8
As an example of the energy savings that may be realized, it is accepted that
1
Calorie to energy is required to heat 1 gram of water by 1 degree Celsius.
This
relationship is applicable irrespective of the energy source used to heat the
water. However, taking electric heating as an example, it is also accepted
that
1 Calorie is equivalent to 0.001 162 222 Watt-hour.
The amount of energy in the shower water depends on the ambient (water
inlet) temperature and the flow rate. Considering a conventional shower of the
prior art, if the inlet water temperature is at 20 degrees Celsius and the
shower
water is at 40 degrees Celsius, this equates to a 20 Celsius temperature rise.
At a flow rate of 10 Ipm, this equates to 200,000 cal/min, or 232Wh/min or
13.9kWh energy consumption.
By comparison, a significantly lower amount of energy is required by a shower
of the present invention when water recirculates via the reservoir. If the
inlet
water temperature (i.e. water from the reservoir is at 35 at Celsius, and the
shower water is at 40 Celsius, it is only necessary for a heater positioned in
the
recirculation circuit to increase water temperature by 5 degrees Celsius. At a
flow rate of 10 Ipm, this equates to 50,000 cal/min, or 58Wh/min or 3.5kWh of
energy consumption.
Thus, based upon the above calculations a shower of the present invention
operating in recirculation mode provides a theoretical energy saving of around
75% where the ambient temperature is 20 degrees Celsius. If the inlet water
temperature supplying a conventional shower was at 1 degree Celsius then
the theoretical energy saving gained by a shower of the present invention
would be around 87%. Thus, even greater energy savings are theoretically
realized when operating a shower of the present invention in a cold climate.
The present invention will now be more fully described by reference to the non-
limiting drawings.
IN THE FIGURES
FIG. 1. illustrates a plan view of the shower base of the invention.
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
9
FIG. 2 illustrates a cross-sectional view of the shower base shown in FIG. 1.
FIG. 3 illustrates a perspective view of a shower system according to the
invention.
FIG. 4 is a schematic diagram of a shower system of the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2 illustrate a shower base structure according to the invention in
plan view and cross-sectional view respectively. The base structure includes a
substantially planar floor area 2 with a reservoir 4 abutting two sides of the
floor. The reservoir 2 includes an outlet 6 to waste and an outlet 8 to the
recirculation pump. While not apparent from the drawings, the floor area is
sloped toward the reservoir. Furthermore, the floor of the reservoir is sloped
toward the outlets 6 and 8 such that water falling on the floor runs to the
nearest portion of the reservoir. Once in the reservoir, the water is then
directed to a central region of the reservoir where outlets 6 and 8 are
positioned.
FIG. 3 illustrates a corner-mounted shower system according to the invention
including a substantially planar floor area 2 with a reservoir 4 abutting two
sides of the floor area. The reservoir 2 includes an outlet 6 to waste and an
outlet 8 to the recirculation. The central pillar 10 houses the recirculation
pump and associated fittings, such as the shower head 12, and water mixer
valve 14.
FIG. 4 is a schematic diagram of a shower system according to the invention.
The system includes a substantially planar floor area 2 with a reservoir 4.
The
reservoir 4 includes an outlet 6 to waste and an outlet 8 to the recirculation
pump 10. A check valve with relief mechanism 12 is included for isolation of
the pump 10 from the outlet 8. The recirculation pump 10 is connected to the
shower head 12, with an electric heater 14 disposed between the two. The
heater 14 is actuated in response to the temperature sensor 16. Flow
switches 18 are also included to provide flow information in the system, one
being disposed downstream from the heater 14 such that the heater 14 is
switched off if flow ceases. A second flow switch 18 is disposed between from
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
the mains water entering by way of mixer valve 26 and pump 10 to provide
information as to whether or not mains water is being admitted to the system.
Hot and cold water is supplied via inlets 20 and 22 respectively, each inlet
fitted with a water pressure reducing valve 24. A water mixer valve 26 is
5 positioned between the water pressure reducing valves 24 and the shower
head 12 allowing regulation of water pressure and temperature by the user.
Vacuum breakers 28 are disposed between the intake side of the recirculation
pump 10 and the mixer valve 26, the breakers actuating to prevent backflow of
water into the mains supply. The system further includes a disinfection
circuit
10 having a disinfectant tank 30 with a fill cap 32, and an electrically
operable
valve 34 actuated by the switch 36. The pump is controlled in part by a
microprocessor control unit 38 actuated by the switch 40.
When the user enters the shower cubicle, he opens mixer valve 26 and adjusts
water temperature and pressure as desired. The shower is not in recirculation
mode meaning that drain outlet 6 is open and the recirculation pump 10 is not
operating. The shower operates like a regular shower in this mode with all
water going to waste, and no water collecting in the reservoir 4. When the
user wishes to commence recirculation mode he closes the drain outlet 6 and
allows the reservoir to fill with water until the outlet 8 is covered with
water. At
that time, the user actuates switch 40 starting the recirculation pump 10.
Water is then drawn from the reservoir 4 to the recirculation pump 10 via the
outlet 8, and pumped to the shower head 12. Once recirculation flow is
established, the user closes mixer valve 26 such that no mains water is being
used, and all flow to the shower is from the reservoir 4. While in
recirculation
mode, the user may spend as long as desired under the shower without further
wastage of water. If sufficient time elapses such that the water temperatures
decreases to less than a predetermined value, this is detected by the sensor
16 and heater 14 is actuated until the water temperature returns to a
comfortable level. At the conclusion of the session, the user will return from
recirculation mode to normal mode by turning off the recirculation pump 10
using switch 40 and then opening the mixer valve 26 and opening the drain 6.
Where it is desired to disinfect the recirculation circuit, the system is put
into
CA 02663223 2009-03-12
WO 2008/031139 PCT/AU2007/000444
11
recirculation mode as described supra and the valve 34 actuated by the switch
36 to admit a disinfectant solution into the system.
Although the present invention has been described by reference to particular
embodiments, it will be apparent to those skilled in the art that variations
and
modifications can be substituted therefore without departing from the
principles
and spirit of the invention.
