U.S. patent application number 09/429939 was filed with the patent office on 2002-02-21 for water freeze control for hot tub spa.
Invention is credited to AUTHIER, MICHEL, LAFLAMME, BENOIT.
Application Number | 20020020014 09/429939 |
Document ID | / |
Family ID | 23705359 |
Filed Date | 2002-02-21 |
United States Patent
Application |
20020020014 |
Kind Code |
A1 |
AUTHIER, MICHEL ; et
al. |
February 21, 2002 |
WATER FREEZE CONTROL FOR HOT TUB SPA
Abstract
A freeze control system for a spa for maintaining the
temperature of the water inside the spa and the spa's associated
piping above the freezing level. Elements include: 1) a heating
element for heating the water, 2) at least one pump for pumping the
heated water, 3) a first sensor for detecting the temperature of
the water in the spa tub, 4) a second sensor for detecting the
temperature of the ambient air around the spa, and 5) a computer
programmed to process signals generated by the first sensor and the
second sensor, wherein the computer selectively activates and
deactivates the heating element and the at least one pump.
Inventors: |
AUTHIER, MICHEL;
(ST-AUGUSTIN, CA) ; LAFLAMME, BENOIT; (QUEBEC
CITY, CA) |
Correspondence
Address: |
JOHN R ROSS III
ROSS PATENT LAW OFFICE
P O BOX 2138
DEL MAR
CA
92014
|
Family ID: |
23705359 |
Appl. No.: |
09/429939 |
Filed: |
October 29, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60106229 |
Oct 30, 1998 |
|
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|
Current U.S.
Class: |
4/541.2 |
Current CPC
Class: |
A61H 33/60 20130101;
A61H 33/005 20130101; A61H 33/0087 20130101; A61H 33/0095
20130101 |
Class at
Publication: |
4/541.2 |
International
Class: |
A47K 003/10 |
Claims
We claim:
1. A freeze control system for a spa for maintaining the
temperature of the water inside the spa and the spa's associated
piping above the freezing level, comprising: A. a heating element
for heating the water, B. at least one pump for pumping the heated
water, C. a first sensor for detecting the temperature of the water
in the spa tub, D. a second sensor for detecting the temperature of
the ambient air around the spa's equipment, and E. a computer
programmed to process signals generated by said first sensor and
said second sensor, wherein said computer selectively activates and
deactivates said heating element and said at least one pump.
2. A freeze control system as in claim 1, wherein said computer
comprises computer components, wherein said second sensor is
mounted so as to be relatively unaffected by heat generated by said
computer components.
3. A freeze control system as in claim 1, wherein said computer
comprises computer components, wherein said second sensor is
mounted so as to be affected by heat generated by said computer
components.
4. A freeze control system as in claim 3, wherein said computer
programming comprises a correction factor to account for the heat
generated by said computer components.
5. A freeze control system as in claim 1, wherein said computer is
programmed to start and run said at least one pump for a
predetermined period of time at intervals based on the temperatures
reported by said second sensor.
6. A freeze control system as in claim 1, wherein said
predetermined period of time is one minute.
7. A freeze control system for a spa for maintaining the
temperature of the water inside the spa and the spa's associated
piping above the freezing level, comprising: A. a heating element
for heating the water, B. at least one pump for pumping the heated
water, C. at least one air blower for blowing air into the spa tub,
D. a first sensor for detecting the temperature of the water in the
spa tub, E. a second sensor for detecting the temperature of the
ambient air around the spa's equipment, and F. a computer
programmed to process signals generated by said first sensor and
said second sensor, wherein said computer selectively activates and
deactivates said heating element, said at least one pump and said
at least one air blower.
8. A freeze control system as in claim 7, wherein said computer
comprises computer components, wherein said second sensor is
mounted so as to be relatively unaffected by heat generated by said
computer components.
9. A freeze control system as in claim 7, wherein said computer
comprises computer components, wherein said second sensor is
mounted so as to be affected by heat generated by said computer
components
10. A freeze control system as in claim 9, wherein said computer
programming comprises a correction factor to account for the heat
generated by said computer components.
11. A freeze control system as in claim 1, wherein said computer is
programmed to start and run said at least one pump and said at
least one blower for a predetermined period of time at intervals
based on the temperatures reported by said second sensor.
12. A freeze control system as in claim 1, wherein said
predetermined period of time is one minute.
Description
[0001] This invention relates to spas, and, in particular to spas
used in climates where water tends to freeze when the temperature
gets cold. This application claims priority of provisional
application Ser. No. 60/106,229 filed Oct. 30, 1998.
BACKGROUND OF THE INVENTION
[0002] A spa (also commonly known as a "hot tub") is a therapeutic
bath in which all or part of the body is exposed to forceful
whirling currents of hot water. Spas are popular throughout the
world but are especially popular in areas of cold climate, such as
at ski resorts and other extremely cold locations. Spa users tend
to find it especially pleasurable to move from an area of extreme
cold to the comfort of a nice, hot spa. However, there is an
unfortunate problem associated with operating and maintaining a spa
in a cold location. If a spa is operated in a climate where water
tends to freeze, unless appropriate measures are taken, water
inside the plumbing of the spa may also freeze and cause damage to
the plumbing. Conventionally, the water in the tub itself is
maintained in its liquid state by the temperature control system of
the spa which keeps the water in the tub at a temperature that is
high enough to prevent freezing of the water in the tub. The
problem with which the industry is faced, however, is that the
water in the plumbing system of the spas will cool down much faster
than the water in the tub itself. Therefore, the water in the
plumbing may freeze while the water in the tub is still in its
liquid state.
[0003] U.S. Pat. Nos. 5,361,215, 5,550,753, and 5,559,720 disclose
a solution to the problem of water freezing in spa plumbing. These
patents teach that the problem can be solved through the
installation of temperature sensors that sense the temperature of
the water in the plumbing and the tub and will circulate the water
through the plumbing if the water in the plumbing gets too
cold.
[0004] A prior art spa 1 is shown in FIG. 1. The prior art spa has
temperature sensor 3 which measures the water temperature inside
tub 7 and temperature sensor 5 which measures the water temperature
inside water heater 9. In the prior art, sensor 5 is used not only
to protect the user from excessive temperature, but also for freeze
protection. To protect the user for excessive temperature, sensor 5
will send an electrical signal to spa controller 11 if it senses a
temperature greater than approximately 119 deg. F. If this
temperature is detected by sensor 5, spa controller 11 will then
shut-off water heater 9.
[0005] As a freeze protection system, the prior art works as
follows. While spa users are using the spa, they can manually set
the temperature of the spa by entering the desired temperature into
spa controller 11 via keypad 15. When the spa is no longer in use,
and the users have left the spa, spa controller 11 continues to
automatically control the temperature of the spa. In the prior art,
when the temperature in spa tub 7 falls below a preset temperature
(as detected by sensor 3), sensor 3 sends a signal to spa
controller 11. Spa controller 11 turns on heater 9 and water pump
13. Hot water is then pumped into spa tub 7. Heater 9 and water
pump 13 will remain on until sensor 3 reports a temperature above
the preset temperature. Likewise, in the prior art, when sensor 5
senses a plumbing temperature less than a preset temperature (for
example, 40 deg. F.), it will cause spa controller 11 to turn on
heater 9 and water pump 13. Hot water is then pumped back into spa
tub 7. Heater 9 and water pump 13 will remain on until sensor 5
reports a temperature greater than the preset temperature (i.e., 40
deg. F.).
[0006] Unfortunately, the solution offered by the prior art has
serious problems. If there is more than one plumbing circuit in a
spa, more than one temperature sensor will be needed. In other
words, each plumbing circuit will require its own temperature
sensor that provides information to spa controller 11. Because of
the extra expense involved, Applicants know of no system that
currently offers separate sensors for each plumbing circuit. Also,
there is no accommodation in the prior art for protection of the
air blower and its associated piping. Although, the air blower
functions to blow air into the spa, it is a common occurrence for
water to leak back through air injector valves 4 into air blower
piping 6 (FIG. 1). Consequently, water inside air blower piping 6
can also expand upon freezing causing severe, costly damage.
Another disadvantage is that the plumbing temperature sensor
disclosed in the prior art is located at the water heater which
causes the sensor to return a value for plumbing water temperature
that is actually warmer than the true water temperature in most of
the plumbing. This means that water in certain parts of the
plumbing may freeze while the water near sensor 5 is still in a
liquid state.
[0007] What is needed is a better freeze control system for
spas.
SUMMARY OF THE INVENTION
[0008] The present invention provides a freeze control system for a
spa for maintaining the temperature of the water inside the spa and
the spa's associated piping above the freezing level. Elements
include: 1) a heating element for heating the water, 2) at least
one pump for pumping the heated water, 3) a first sensor for
detecting the temperature of the water in the spa tub, 4) a second
sensor for detecting the temperature of the ambient air around the
spa, and 5) a computer programmed to process signals generated by
the first sensor and the second sensor, wherein the computer
selectively activates and deactivates the heating element and the
at least one pump.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a prior art spa.
[0010] FIG. 2 shows a first preferred embodiment of the present
invention.
[0011] FIG. 3 shows a second preferred embodiment of the present
invention.
[0012] FIG. 4 shows a perspective view of the second preferred
embodiment of the present invention.
[0013] FIG. 5 shows a detailed view of the spa controller.
[0014] FIG. 6 shows a perspective view of the first preferred
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] A detailed description of a preferred embodiment of the
present invention is seen by reference to FIGS. 2-6.
[0016] First Preferred Embodiment
[0017] As seen in FIG. 2, spa 2 contains sensor 17. In a first
preferred embodiment sensor 17 is mounted to mounting board 22
underneath spa skirt 20 near spa 2's piping, as shown in FIG. 6.
This location is chosen so that sensor 17 is exposed to the air
that is near the piping system of spa 2. In a preferred embodiment,
spa controller 12 contains a CPU that is programmed to maintain the
temperature of the water in spa tub 7 and the water in spa 2's
piping in an optimum operating range (i.e., below a level that is
too hot for a user, but above the level which would cause freezing
of the water in spa 2's piping). As in the prior art, sensor 3
senses the temperature of the water in spa tub 7. Sensor 5 senses
the temperature of water near water heater 9.
[0018] In the present invention, sensor 3 is still part of the
freeze control system in that when the temperature in spa tub 7
drops below a first predetermined value, sensor 3 sends a signal to
spa controller 11. This first predetermined value can be high
(i.e., 104 deg. F.) for spas that get fairly regular use, or low
(i.e., 59 deg. F) for example, for a homeowner who did not plan on
using his spa for an extended period of time. In the first
preferred embodiment, Spa controller 11 is model number SSPA,
manufactured by Gecko Electronique with offices in Quebec City,
Quebec, Canada. Spa controller 11 turns on heater 9 and water pump
13 when the temperature in spa tub 7 drops below the first
predetermined value. Hot water is then pumped back into spa tub 7.
Heater 9 and water pump 13 will remain on until sensor 3 reports a
second predetermined temperature slightly above the first
predetermined temperature. However, in the preferred embodiment of
the present invention, sensor 5 is no longer part of the freeze
control system. Instead, sensor 5 is used only to shut off heater 9
when the temperature at heater 9 gets too hot (approximately 119
deg. F.).
[0019] In the present invention, sensor 17 has been added to the
system and senses the temperature of ambient air around spa 2's
piping. In the preferred embodiment of the present invention,
sensor 17 is a HT Thermistor sensor (part no. Gecko: 530SB0016)
manufactured by Ishicuka Electronic with offices in Japan.
[0020] In this first preferred embodiment, sensor 17 detects the
true value of ambient air near the piping of spa 2. The programming
of spa controller 12 has been modified from spa controller 11 (FIG.
1) to include the ability to be able to utilize information
reported by sensor 17 to better regulate the water temperature of
spa 2 to prevent freezing of its associated piping.
[0021] Applicants call this programming "Smart Winter Mode" and its
functionality is illustrated by reference to Table 1 below.
1 TABLE 1 Ambient Air Temp Conduct a 1 minute purge every: 40 deg.
F. 2 hours 28 deg. F. 1 hour 14 deg. F. 30 minutes 5 deg. F. 15
minutes
[0022] In the first preferred embodiment, as the temperature at
sensor 17 decreases to 40 deg. F sensor 17 will send an electrical
signal to spa controller 12. Spa controller 12 will then start
water pumps 13 and 14 and air blower 16. They will each run for 1
minute every two hours. As shown in Table 1, if the temperature
drops to 28 deg. F at sensor 17, water pumps 13 and 14 and air
blower 16 will conduct a 1-minute purge every hour. Likewise, when
sensor 17 reports a temperature of 14 deg. F, the system will purge
every 30 minutes and at 5 deg. F. the system will purge every 15
minutes. In the first preferred embodiment, as an extra added
measure of protection, after the ambient has risen above 40 deg.
F., spa controller 12 will continue to run water pumps 13 and 14
and air blower 16 for one minute every 2 hours for the next 24
hours.
[0023] Second Preferred Embodiment
[0024] A second preferred embodiment is seen by reference to FIGS.
3, 4 and 5. In the second preferred embodiment, sensor 17 is
attached directly to printed circuit board (PCB) 12A inside spa
controller 12, as shown in FIGS. 4 and 5. In the second preferred
embodiment, Spa controller 12 is model number SSPA, manufactured by
Gecko Electronique with offices in Quebec City, Quebec, Canada. By
attaching sensor 17 directly to PCB 12A, a substantial cost savings
is realized in that the expense of mounting sensor 17 at another
location near spa 2's piping (as was shown in the first preferred
embodiment) is avoided. In other words, when sensor 17 is mounted
on PCB 12A, funds that would be spent on cabling, housing and
connectors are saved. However, it should be noted that when sensor
17 is mounted to PCB 12A, sensor 17 is exposed not only to ambient
air temperature, but also to the temperature of the area around PCB
12A which is heated by the other components also attached to PCB
12A. Hence, a correction factor needs to be programmed into spa
controller 12 account for the heat generated by spa controller 12's
components. Through experimentation for spa controller 12 model
number SSPA, Applicants have determined the following correlation
shown in Table 2:
2TABLE 2 Conduct a Temp at Sensor 17 Ambient Air Temp. 1 minute
purge every: 68 deg. F. 40 deg. F. 2 hours 59 deg. F. 28 deg. F. 1
hour 54 deg. F. 14 deg. F. 30 minutes 50 deg. F. 5 deg. F. 15
minutes
[0025] In the second preferred embodiment, as the temperature at
sensor 17 decreases to 68 deg. F (ambient air temp.=40 deg. F),
sensor 17 will send an electrical signal to spa controller 12. Spa
controller 12 will then start water pumps 13 and 14 and air blower
16. They will each run for 1 minute every two hours. As shown in
Table 1, if the temperature drops to 59 deg. F at sensor 17, water
pumps 13 and 14 and air blower 16 will conduct a 1-minute purge
every hour. Likewise, when sensor 17 reports a temperature of 54
deg. F, the system will purge every 30 minutes and at 50 deg. F.
the system will purge every 15 minutes. As an extra added measure
of protection, after the ambient has risen above 40 deg. F. (i.e.,
sensor 17 reports a Temp =68 deg. F), spa controller 12 will
continue to run water pumps 13 and 14 and air blower 16 for one
minute every 2 hours for the next 24 hours.
[0026] The above-described invention is an improvement over the
prior art in that it provides a much more reliable and effective
manner of preventing freezing while at the same time minimizing
costs.
[0027] While the above description contains many specifications,
the reader should not construe these as limitations on the scope of
the invention, but merely as exemplifications of preferred
embodiments thereof. Those skilled in the art will envision many
other possible variations are within its scope. For example,
although the above embodiments described a spa that has an air
blower, there are many spas that do not have air blowers. The above
invention would work equally well for spas without air blowers. For
example, spa controller 12 would be programmed to start the water
pumps when sensor 17 detected a low temperature. Also, although the
above embodiments discuss using model number SSPA for spa
controller 12, those of ordinary skill in the art will recognize
that it would be possible to substitute a different spa controller
for spa controller 12. For the second preferred embodiment, if a
different spa controller 12 is used, a new correction factor would
have to be calculated to determine a correlation table appropriate
for the different spa controller. Accordingly the reader is
requested to determine the scope of the invention by the appended
claims and their legal equivalents, and not by the examples which
have been given.
* * * * *