Note: Descriptions are shown in the official language in which they were submitted.
21~22~G
BACKGROUND OF THE INVENTION
This invention relates to a water saving recirculating
system for use with a conventional water supply. More
particularly the invention relates to a system for detecting
whether water which is destined to be discharged from a hot
water faucet is sufficiently hot. If it is not, the water is
diverted from the faucet and re-circulated to a hot water
tank.
When a hot water faucet is first opened the water which
discharges from it is usually not hot. It is customary to
allow the water to run until it reaches the desired temper-
ature. During this time the water which discharges from the
faucet flows down the drain and is wasted. Also wasted is the
energy which is expended in heating the water and in pressur-
izing it so that it will reach the faucet.
A number of systems have been devised to re-use or re-
cycle the water so that it is not wasted. Examples of such
systems are described in the following Letters Patent of the
United States: patent no. 5,261,443 to Walsh; patent no.
5,205,318 to Massaro et al.; no. 5,339,859 to Bowman; no.
5,277,219 to Lund; no. 4,697,614 to Powers et al.; no.
4,201,518 to Stevenson; no. 3,799,181 to Maddren; no.
4,331,292 to Zimmer; no. 4,936,289 to Peterson; no. 4,606,325
21622~6
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to Lujan; no. 4,450,829 to Morita et al.; no. 3,776,261 to
Houghton; 5,009,572 to Imhoff et al.; no. 5,385,168 to Lund;
no. 5,042,524 to Lund; no. 5,105,846 to Britt; and no.
4,945,942 to Lund.
Known systems for re-using or re-cycling water from a
hot water faucet have a number of shortcomings. In some
systems, unused water in the hot water line is circulated to
the cold water line. While such water may not be sufficiently
hot it may be warm and any heat which it has is wasted in the
cold water line. Moreover the known systems require both a hot
water and a cold water line and are usually not suitable where
there is only one line such as in a packing plant or a factory
where only hot water is required.
Many known systems have another disadvantage. Some
require auxiliary pumps to continuously recirculate the water.
Such pumps are costly and may malfunction. If the pumps mal-
function the entire system will break down.
SUMMARY OF THE INVENTION
According to the present invention, water which is in-
sufficiently hot in a hot water line is re-cycled to the hot
water heater and not to the cold water line. The system is
made up of relatively inexpensive and readily available com-
ponents.
216220~
The invention may be broadly described as including
heating means for heating water to a temperature elevated
above ambient temperature; a main water-carrying line
extending from the heating means and terminating at an outlet
remote from the heating means; a sensor for detecting the
temperature of water in the main line in the vicinity of the
outlet; a first valve disposed in the main line and opening to
allow water to flow therethrough when the water temperature
detected by the sensor exceeds a pre-determined value; a
recirculating water-carrying line extending from the main line
between the sensor and the first valve and terminating at the
heating means; and a second valve disposed in the
recirculating line and closing to prevent water from flowing
therethrough when the water temperature detected by the sensor
exceeds a pre-determined value.
DESCRIPTION OF THE DRAWINGS
The water saving recirculating system of the invention is
described with reference to the accompanying drawings in
which:
Figure 1 is a schematic drawing of the system;
Figure 2 is a perspective view of the components which
make up the system;
Figure 3 is a schematic view of the components illust-
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rated in Figure 2 showing the direction of flow of water when
its temperature is below a predetermined value; and
Figure 4 is another schematic view of the components
showing the direction of flow of water when its temperature is
at or above a predetermined value.
Like reference characters refer to like parts throughout
the description of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to Figure 1 water from a heating means
such as a conventional hot water tank (not illustrated) flows
through a main water-carrying line 10 to a probe 12. That
probe is electrically connected to an adjustable temperature
sensor 14. The sensor generates an electrical signal when the
temperature at the probe is below a predetermined value.
Downstream of the probe is an electrical pressure switch
16 which detects a drop in pressure caused by the flow of
water. When the pressure drops, switch 16 closes. That switch
and probe 12 are connected in series in a circuit described
below.
21 ~220~
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Water downstream of the pressure switch flows through one
of two lines, main line lOa or recirculating line 18. Line lOa
is an extension of the main line and runs to a first pressure
sensitive valve 20. That valve is spring loaded and is
normally closed but opens when the pressure differential of
water between the upstream and downstream sides of the valve
exceeds a predetermined value.
Downstream of valve 20 is a manually operated shut-off
valve 22. Downstream of valve 22 is a faucet (not illustrated)
which is the outlet from which water discharges at 24. Valve
22 may alternatively be the faucet. If valve 22 is a shut-off
valve, it will normally be open but may be closed manually to
shut down the main line entirely.
Water in recirculating line 18 flows to a second valve 28
which is activated by a solenoid 30. The solenoid is connected
in series with sensor 14 and pressure switch 16. Provided
switch 16 is closed, the signal which the sensor generates
when the temperature at the probe is below a predetermined
value will cause the solenoid to open valve 28. Water may then
recirculate through line 18 and through a check valve 40 to
the hot water tank.
With reference to Figure 2, a probe and sensor 12, 14
suitable for use in the system is sold under the trade mark
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"Aquastat" and is described as a model no. L6008A Controller
manufactured by the Honeywell Company of Minneapolis,
Minnesota, U.S.A. The pressure switch 16 is widely available
at plumbing outlets. Models 210CA and 211CA solenoid valves
sold by Alco Controls Division of Emerson Electric Company of
St. Louis, Missouri, U.S.A. are suitable for use as a solenoid
and solenoid valve 30, 28. Valve 20 is described below and
shut-off valve 22 is of conventional construction.
With reference to Figure 3 water in the main line 10
flows by probe 12 which monitors the temperature. If the
temperature is below a predetermined value, sensor 14
generates an electrical signal. If pressure switch 16 detects
movement of the water it will close and the signal will cause
solenoid 30 to open valve 28 with resulting flow of water
through recirculating line 18 and check valve 40. That water
will discharge into the hot water tank. The pressure of water
in line lOa is insufficient to overcome the bias of coil
spring 42 of valve 20 and the valve is accordingly closed by
ball 44 which is forced into the inlet of the valve by the
spring.
With reference to Figure 4, the temperature of water is
above the predetermined value and sensor 14 does not generate
a signal. Valve 28 which is normally closed rem~; n~ SO since
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there is no signal from the sensor to activate the solenoid.
Since valve 28 is closed, the pressure of water in lines
10 and lOa will increase. The pressure of the water on ball 44
will overcome the bias of coil spring 42 and cause valve 20
to open. Valve 22 is also open and water will discharge from
outlet 24.
In operation, before the hot water faucet is opened, no
water flows through main line 10, lOa because valve 20 is
closed. No water flows through recirculating line 28 as well.
That is because pressure switch 16 is open since it detects no
movement in line 10. The circuit which activates solenoid 30
is likewise open and normally closed valve 28 remains closed.
When the hot water faucet is opened, the pressure on the
upstream side of valve 20 reduces momentarily and the valve
opens to allow a small quantity of water to flow through it.
That flow of water is detected by switch 16 and the switch
will close thereby closing the electric circuit from sensor 14
to the solenoid. The solenoid will now respond to a signal
generated by the sensor.
Assuming that the temperature detected by the sensor is
below a predetermined value, the sensor will cause the
solenoid to open valve 28 and water will flow through the
recirculating line and discharge into the hot water tank.
21622~6
When the temperature of the water reaches the pre-
determined value, sensor 14 will no longer generate the signal
necessary to keep valve 28 open and it will close. The
pressure of water on valve 20 will accordingly increase and it
will open and water will discharge from the hot water faucet.
When the faucet is turned off, water will cease flowing
in the main line and switch 16 will open. Switch 16 will
remain open as long as there is no movement of water in the
main or recirculating lines.
Switch 16 thus prevents the water from beginning to flow
through the recirculating line when its temperature falls. In
the absence of such a switch, when the temperature of the
water falls below the predetermined value, sensor will cause
the solenoid to open valve 28 and water will begin to flow
through the recirculating line. The flow in the line will stop
when the water temperature excee~s the predetermined value but
will resume whenever the water temperature is below that
value.
It will be understood of course that modifications can be
made in the preferred embodiments illustrated and described
herein without departing from the scope and purview of the
invention as defined in the appended claims.
