Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02486194 2004-10-27
APPARATUS AND METHOD FOR CONTAINING AND REGULATING THE
PRESSURE IN A PRESSURE VESSEL
BACKGROUND OF THE INVENTION
Some homes and businesses are not served by municipal water services. These
homes
and businesses generally utilize a private well to solve their water needs.
With a private well,
water is drawn from a water bearing aquifer in the ground and pumped to a
storage tank
containing a fixed amount of air. As water enters the tank, the air volume
occupied by the air
is reduced and the pressure within the tank rises. The tank is therefore a
pressure
accumulator that delivers water to a faucet or other end use location without
requiring the
pump to cycle every time water is drawn from the tank.
SUMMARY OF THE INVENTION
Some aspects of the present invention are directed toward improving the
process of
manufacturing and preparing a pressure tank assembly. During conventional
manufacturing
processes, the pressure tank is generally pressure tested. As part of the
pressure test, an air
pressure sensing assembly or regulator valve assembly is attached to the tank
to seal an
opening in the tank and to introduce air into the tank. After the pressure
test, the regulator
assembly is removed from the tank so the tank can be easily painted. However,
this step also
causes the tank to be depressurized. Once the tank is painted, a pressure
regulator valve
assembly is attached to the tank again and the tank is pressurized again. The
tank is generally
then sold with the pressure regulator valve attached and with the tank
pressurized.
The inventors have developed a method for manufacturing a tank that can reduce
one
or more of these redundant steps. Furthermore, they have developed a tank and
a pressure
sensing assembly that can be used with said method. For example, some
embodiments relate
to a method of manufacturing a water storage tank for a well. The method can
include one or
more steps such as forming a pressure vessel having an opening, an interior
volume, and an
elastic member located inside the pressure vessel to separate the interior
volume into a water
storing volume and an air storing volume; installing a seal over the opening,
wherein the seal
is capable of sealing the entire opening and is adapted to be punctured by a
pressure switch
mounting assembly; pressurizing the tank with air; preventing air from
escaping the
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pressurized tank through the opening with the seal; and packaging the
pressurized tank for
shipping while the tank is pressurized.
Other embodiments relate to a water storage tank adapted to selectively
release water
and refill with water delivered from a well via a water pump, wherein the tank
comprises a
pressure vessel having an opening and an interior volume, an elastic member
located inside
the pressure vessel and separating the interior volume into a water storing
volume and an air
storing volume, and a seal located over the opening. The seal allows the tank
to be
pressurized and remain pressurized without additional structure closing the
opening.
Yet other embodiments relate to an apparatus connectable to a water storage
tank
(having a volume of stored air) that can selectively release water and refill
with water
delivered from a well via a water pump. The apparatus comprises a conduit
connectable with
the tank and defining an air passage in communication with the stored air in
the tank and an
air pressure switch coupled to the conduit. The air pressure switch
communicates with the air
passage and is operable to activate the pump if the air pressure within the
tank drops below a
first limit. A projection is contiguous with and extends from the conduit in a
direction away
from the pressure switch. The projection has an end capable of piercing a seal
on the tank.
Once a conventional tank (that uses air pressure within the tank to trigger
the pump) is
installed, problems can arise when air Ieaks from the tank into the
atmosphere. This can
occur in some situations because the installer may have used the air pressure
sensing
assembly as a handle to move the tank into its operating position, which could
damage the
valve and cause a leak. Leaks, however, can occur for other reasons as well.
Regardless of
how the leak develops, as the air leaks out, a reduction in pressure will
cause the pressure
switch to activate the pump. Although the pump will deliver water to the tank,
the air
pressure will generally not rise to the preset limit needed to turn the pump
off due to the leak.
Furthermore, since the water is prevented from reaching the pressure switch,
the water
pressure cannot turn the pump off. Consequently, the pump will continuously
add water to
the tank until there is a pump failure or until the pressure system fails by
developing a leak on
the waterside. For example, seams of some conventional tanks have ruptured due
to the
water pressure within the tank.
Thus, some embodiments of the present invention axe adapted to avoid this
problem.
For example, some embodiments relate to a tank and pressure sensing assembly
that does not
need to be attached to the tank until the tank is in its final operating
position. If the
pressuring sensing assembly is not attached to the tank, it cannot be used as
a handle.
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Other embodiments also relate to a water storage apparatus for selectively
storing and
releasing water delivered from a well via a water pump. Specifically the
apparatus has a
pressure vessel having an opening and an interior volume and an elastic member
inside the
pressure vessel. The elastic member separates the interior volume into a water
storing
volume and an air storing volume. The water storing volume communicates with
the water
pump and fills with water supplied by the pump. The air storing volume
contains a fixed
amount of air. The air storing volume decreases in response to water being
pumped into the
water storing volume, and the pressure within the tank consequently rises. On
the other hand,
the pressure in the tank decreases as water is drawn from the tank and the air
storing volume
expands. A conduit is located in the pressure vessel opening and defines an
air passage in
communication with the air storing volume. An air pressure switch is located
in
communication with the air passage and adapted to activate the pump in
response to the air
pressure in the air storing volume dropping below a first limit and
deactivating the pump in
response to air pressure rising above a second limit. The second limit is
greater than the first
1 S limit. Also, a piercing member is contiguous with the conduit and extends
into the air storing
volume to pierce the elastic member in the event that the elastic member
contacts the piercing
member due to the air storing volume shrinking below a normal operating range
of volumes.
Other embodiments are directed to a water storage apparatus for selectively
storing
and releasing water delivered from a well via a water pump. The water storing
apparatus can
include a pressure vessel having an opening and an interior volume and an
elastic member
inside the pressure vessel. The elastic member separates the interior volume
into a water
storing volume and an air storing volume. A conduit is positioned in the
pressure vessel
opening to define an air passage in communication with the air storing volume.
An air
pressure switch communicates with the air passage and is adapted to activate
the pump in
response to the air pressure in the air storing volume dropping below a first
limit. A piercing
member is connected with the conduit and extends through the opening and into
the air
storing volume to pierce the elastic member in the event that the elastic
member contacts the
piercing member due to the air pressure dropping below a second limit less
than the first
limit.
Further aspects of the present invention, together with the organization and
operation
thereof, will become apparent from the following detailed description of the
invention when
taken in conjunction with the accompanying claims and drawings, wherein like
elements
have like numerals throughout the drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is further described with reference to the accompanying
drawings, which show certain embodiments of the present invention. However, it
should be
noted that the invention as disclosed in the accompanying drawings is
illustrated by way of
example only. The various elements and combinations of elements described
below and
illustrated in the drawings can be arranged and organized differently to
result in embodiments
which are still within the spirit and scope of the present invention.
In the drawings, wherein like reference numeral indicate like parts:
FIG. 1 is a schematic elevation view of a water pressure system;
FIG. 2 is an exploded partial cross-section of a diaphragm pressure tank and
pressure
regulator embodying aspects of the invention;
FIG. 3 is an exploded partial cross-section of a pressure tank and pressure
regulator
embodying aspects of the invention;
FIG. 4 is a partial cross-sectional side view of a pressure regulator mounted
on a
pressure tank;
FIG. 5 is a partial cross-sectional side view of a pressure regulator mounted
on a
pressure tank;
FIG. 6 is a partial cross-sectional side view of a pressure regulator mounted
on a
pressure tank;
FIG. 7 is a partial cross-sectional side view of a pressure regulator mounted
on a
pressure tank;
FIG. 8 is a cross-section of the pressure tank illustrated in FIG. 2 having a
leak on the
air storage side of the tank; and
FIG. 9 is a cross-section of the pressure tank illustrated in FIG. 3 having a
leak on the
air storage side of the tank.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
As illustrated in FIG. 1, a water pressure system for a well generally has a
drop pipe
extending into a water bearing aquifer, and a pump is used to deliver water
from the aquifer
to a pressure vessel or storage tank 12. Several types of pumps can be used,
such as
submersible pumps and non-submersible pumps. Water from the pressure tank 12
can be
distributed from the tank for use.
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The pressure tank 12 generally holds a reserve supply of water under pressure
within
the tank until it is needed. As water is drawn from the tank 12, the pressure
within the tank
12 forces the water out of the tank 12 and consequently the pressure gradually
decreases. A
pressure switch 14 coupled to the tank 12 is used to maintain the pressure
within the tank 12
between a preset minimum value and a preset maximum value. Upon reaching the
preset
minimum pressure, the pressure switch 14 automatically activates the pump.
Water is then
pumped into the tank 12 to replenish the tank 12 with water and to build up
the pressure
within the tank 12 to the preset maximum value. Once the pressure within the
tank 12 has
reached the preset maximum value, the pressure switch 14 stops the pump from
operating.
An elastic member 15 typically separates the pressure tank 12 into a water
storing
portion 18 and an air storing portion 21 as illustrated in FIGS. 2 and 3. The
elastic member
is generally a diaphragm or bladder as illustrated in FIG. 2. However, in
other
embodiments, the elastic member can be bag or balloon-like member as
illustrated in FIG. 3.
A diaphragm or bladder (FIG. 2) generally attaches to the sides of the tank
along the inner
15 periphery of the tank 12 to separate the two portions. The construction of
the tank and elastic
members are well understood in the art and therefore will not be discusses in
detail.
Under normal operating conditions the pressure in the air storing portion 21
and the
water storing portion 18 are about the same. Therefore, the pressure switch 14
can sense the
pressure in either portion. The operation of an air pressure switch operates
as follows. As
the water level in the tank 12 drops, the volume 18 within the tank 12
occupied by the water
drops. This allows the fixed amount of air to increase the amount of space or
volume it
occupies, and consequently causes the air pressure to drop. Once the air
pressure drops
below the preset minimum limit, the pressure switch 14 activates the pump to
deliver more
water to the tank and increase the pressure within the tank 12.
The air storing portion 21 can be pressurized with air via an air valve 32
located on
the side of the tank (FIG. 2) or via an air valve 32 located on an air
pressure sensing assembly
33 (FIG. 3). Regardless of the location of the valve 32, the air storing
portion 21 of the tank
12 has an opening or spud 30 that receives the air pressure sensing assembly
33.
Some embodiments of the invention have a seal 39 positioned over the opening
30 or
in the opening 30. Depending upon how the seal 39 is used, it can help reduce
the number of
times the tank needs to be pressurized and depressurized while manufacturing
the tank 12.
Conventionally, an air gauge would be threaded into the spud, and the tank
would be pressure
tested. Then the air gauge would be removed so the tank could be painted. Next
the air
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gauge would again be threaded into the spud so the tank could be pressurized.
The
pressurized tank would then be shipped with the air gauge installed.
With the use of the seal 39 of the present invention, the opening of the tank
12 can be
sealed while being manufactured. The tank can then be pressurized without the
need to
attach the air pressure sensing assembly 33 to the tank 12. Additionally,
since the air
pressure sensing assembly 33 is not attached to the tank prior to the painting
process, it does
not need to be detached. Consequently, the tank 12 can remain pressurized
during the
painting operation. Additionally, the pressurized tank 12 can be shipped
without the air
pressure sensing assembly 33 attached. The potential for damage to the air
pressure sensing
assembly 33 can be reduced by shipping it separately from the tank.
The seal 39 can be made from several different types of materials, such as
elastic,
resilient, inelastic, or frangible materials depending upon the purpose of the
seal 39. For
example, as will be discussed further below, the seal 39 may be able to
selectively open and
close the air volume. In such a situation, elastic materials may be desirable.
The seal 39 can be attached to the inside of the tank 12, to the outside of
the tank, or a
combination of the two. The seal can also be located entirely on one side of
the opening 30,
in the opening 30, on both sides of the opening 30, or combination of the
above. The seal 39
can be coupled to the tank m one or more conventional fastening techniques,
such as with
adhesive or cohesive bonds, welds, rivets, friction fits, interference fits,
other conventional
fasteners, and the like.
The seal 39 can be punctured or pierced by a piercing member 42 located at the
end of
the air pressure sensing assembly 33 while the air pressure sensing assembly
33 is being
attached to the tank 12. Preferably, the seal is not fully punctured or
pierced until the air
pressure sensing assembly 33 is sufficiently engaged with the opening 30 of
the tank 12 to
prevent leakage of air. For example, if the air pressure sensing assembly 33
were threaded
into a spud surrounding the opening 30, the piercing member 42 would not fully
pierce the
seal 39 until the threads of the air pressure sensing assembly 33 and the spud
were
sufficiently engaged to prevent leakage. However, this does not mean that the
air pressure
sensing assembly 33 is resting in its fully engaged position with the spud.
Rather, it only
needs to be engaged sufficiently enough to prevent substantial leakage.
Preferably, it
prevents all leakage.
The piercing member 42 can have a variety of embodiments. For example, it can
be a
solid needle, a hollow needle, a blade, a blunt end projection, a cylindrical
projection, a
pointed objected, a helical projection, and the like. In some preferred
embodiments, the
CA 02486194 2004-10-27
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piercing member 42 is similar to a hypodermic needle. As illustrated in FIGS.
4-7, the
piercing member 42 of some embodiments has a hollow center that is in
communication with
a conduit 45 of the air pressure sensing assembly 33. Specifically, the hollow
center is
aligned with the conduit 45. This allows air to travel through the projection
and into the air
S pressure sensing assembly 33. In some embodiments, the piercing member 42
can be formed
integrally with the air pressure sensing assembly 33 as shown in FIGS 4 and 5.
However, in
other embodiments, the piercing member 42 can be formed separately from and
positioned
contiguous with and extend from the air pressure sensing assembly 33. In such
embodiments,
the piercing member could have a shoulder 43 that rests on a ledge 44 within
the opening 30
as shown in FIGS. 6 and 7.
The air pressure sensing assembly 33 can be constructed several different ways
and
with several different components - as is understood in the art. For example,
FIGS. 4 and 6
illustrate two different configurations of an air pressure sensing assembly
33. Each assembly
33 has a conduit 45 coupled to the opening of the tank 12 and in communication
with the air
storing portion 21 of the tank. A pressure switch 14 and an air gauge 51 are
coupled to the
conduit 45 and in communication with the air storing volume via the conduit
45. As
illustrated, the arrangement of these elements in FIG. 4 is slightly different
than the
arrangements in FIG. 6. A person having ordinary skill in the art will
understand that other
arrangements are possible and various components can be added or removed. Such
variations
fall within the spirit and scope of the present invention. For example, the
air gauge 51 may
not be necessary in some embodiments and could therefore be omitted.
The pressure switch 14 and the air gauge 51 sense the pressure within the
conduit 45.
The air gauge 51 provides a visual indication of pressure within the tank 12.
The pressure
switch 14 also senses the pressure within the tank 12 and compares the
measured pressure
with preset limits to determine whether to active the pump. If the pressure is
below the
desired pressure range, the pump will deliver water to the tank I Z to
increase the pressure
within the tank 12. When the pressure switch 14 activates the pump, it can
also deactivate
the pump once the pressure rises above another preset limit at the upper end
of the desired
operating range. In some typical systems, for example, the pump will be
activated when the
pressure within the tank drops below thirty pounds per square inch and will be
deactivated
when the pressure exceeds fifty pounds per square inch. Other preset limits
are also used and
fall within the spirit and scope of the present invention.
FIGS. S and 7 illustrate two other configurations of an air pressure sensing
assembly
33. Like the previous assemblies, these assemblies 33 each have a conduit 45
coupled to the
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opening 30 of the tank 12 and in communication with the air storing portion 21
of the tank.
In addition to the pressure switch I4 and air gauge 51 seen in the previous
assemblies, this
assembly also has an air valve 32 attached to the conduit 45 and in
communication with the
air storing volume via the conduit 45. As illustrated, the arrangement of
these elements in
FIG. 5 is slightly different than the arrangement in FIG. 7. A person having
ordinary skill in
the art understands that other arrangements are possible and various
components can be
added or removed. Such variations fall within the spirit and scope of the
present invention.
The assemblies 33 shown in FIGS. 4 and 6 can allow the tank to be tested in a
different manner than the assemblies shown in FIGS. 5 and 7. However, they do
not
necessarily need to be tested differently. For example, the air pressure
sensing assemblies 33
illustrated in FIGS. 4 and 6 do not need to be attached to the tank 12 for the
tank 12 to be
pressure tested. As illustrated, an air valve 32 is attached to the tank 12
separate from the air
pressure sensing assembly 33. As such, air can be introduced through this
valve 32 to
pressurize the tank without the need to attach the air pressure sensing
assembly 33.
In some embodiments, however, the air pressure sensing assembly 33 can be
coupled
to the tank for some operations and later removed without losing a substantial
amount of
pressure. These embodiments can utilize a resilient, self closing seal 39
similar to the valves
used on inflatable athletic balls. Thus, the piercing member 42 can penetrate
the seal 39 and
be removed from the seal 39 with the seal preventing substantial air loss.
This arrangement
would typically be used with the air pressure sensing assemblies 33
illustrated in FIG. 5,
wherein the assembly 33 has an air valve 32 and the piercing member 42 is
integral with the
assembly 33. However, they can also be used with other assemblies 33, such as
the
embodiment illustrated in FIG. 4. Specifically, the assembly 33 illustrated in
FIG. 5 can be
attached to the tank 12 and used to introduce air into the tank 12 via air
valve 32 during the
pressure test. The assembly 33 can then be removed for the painting operation.
Upon
removal of the air pressure sensing assembly 33, the resilient, self closing
seal 39 will seal
the opening 30 and prevent substantial pressure losses from occurnng. Then,
during later
operations, the air pressure sensing assembly 33 can be coupled to the tank
12. Although this
method and assembly requires the additional steps of removing and re-attaching
the air
pressure sensing assembly 33 when compared to the previously discussed
embodiments, it
still eliminates the need to depressurize and repressurize the tank 12 when
compared to
conventional tanks.
Under certain conditions, the piercing member 42 can also pierce the elastic
member
15 that separates the water containing portion 18 from the air containing
portion 21. For
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example, if the air containing portion 21 portion were to develop an
atmospheric leak as
shown FIGS. 8 and 9, the pressure sensed by the pressure switch would drop and
eventually
trigger the pump to activate. Since the elastic member 15 separates the water
containing
portion 18 from the air containing portion 21, the addition of water to the
tank 12 will not
cause an increase in pressure in the air containing portion 21. Theoretically,
the pump would
continue to operate until the tank 12 or a waterline developed a leak or
burst. However, if
water were able to reach the pressure switch, the water pressure could cause
the pump to turn
off.
One way to allow water to reach the pressure switch is to pierce the elastic
member 1 S
with the piercing member 42. As water continues to fill the tank, the elastic
member 1 S will
be pushed closer to top of the tank 12. Eventually, the elastic member 15 will
contact and be
pierced by the piercing member 42. This will allow water to penetrate the air
storing portion
and contact the pressure switch to deactivate the pump. By aligning the
piercing member 42
with the conduit 45, water can reach the pressure switch 14 relatively
quickly. Specifically,
since the conduit 45 is in communication with the hollow portion of the
piercing member 42,
water can enter the conduit 45 immediately after the piercing member 42
pierces the elastic
member 15. The owner of the tank 12 may be alerted to the air leak by the pump
cycling
every time water is drawn from the tank.
The embodiments described above and illustrated in the figures are presented
by way
of example only and are not intended as a limitation upon the concepts and
principles of the
present invention. As such, it will be appreciated by one having ordinary
skill in the art that
various changes in the elements and their configuration and arrangement are
possible without
departing from the spirit and scope of the present invention. For example,
various
alternatives to the certain features and elements of the present invention are
described with
reference to specific embodiments of the present invention. With the exception
of features,
elements, and manners of operation that are mutually exclusive of or are
inconsistent with
each embodiment described above, it should be noted that the alternative
features, elements,
and manners of operation described with reference to one particular embodiment
are
applicable to the other embodiments.
