Technical field
[0001] The present invention relates to a sports ball pressurizing container, and to a method
of pressurizing sports balls.
Prior art
[0002] The present invention relates to pressurized sports balls. Sports balls are generally
made of rubber and pressurized with air or nitrogen to about 2 bar. After manufacture
sports ball may be placed in a pressurized plastic can to prevent air loss from the
balls as the rubber is permeable to gas. Prior to usage, this can is opened. From
that moment, the sports balls lose gas and pressure. Balls can generally be used for
1 month of play when stored at ambient pressure. Already during this period, the bounciness
of these balls decreases. This becomes especially noticeable when playing with a mix
of old and new balls, which results in a large difference of bounce.
[0003] New balls with proper pressure may be hit many meters farther with the same hit as
a "dead" ball that may have an internal pressure of only 1 to 1.5 bar that end up
in the net. This leads to frustration during an otherwise great game. Mixing of old
and new balls is especially a problem for tennis trainers, who usually teach with
a cart and a crate with larger numbers of balls, for instance 150 balls. Frequent
ball replacement to avoid this pressure problem is costly and may be challenging to
the environment. Balls may be stored at 2 bar pressure to prevent pressure loss but
since trainer tennis balls are used daily for many hours, during which they are exposed
to ambient pressure, they still lose pressure quickly.
US 3888347 discloses a ball container with an integrated pump.
US 4046491 discloses an apparatus for preserving the ball pressure during storage.
US 4101029 discloses a container with gas supply, a pressure gauge, and a pressure release valve.
US 4729472 relates to a monitoring device for recording and displaying the times the tennis
balls have been used.
US 5002196 discloses a container with a compressor, a pressure sensor switch and optionally
a manually operable pressure release valve.
US 5083415 describes pressurizing a container with a piercing probe and subsequently heat-sealing
the piercing.
US 5397018 discloses a storage container with a pressure compensation device for controlling
a compressor as well as a player's container that can be provided with a hand pump,
a pressure control valve and a pressure meter.
US 7658211 discloses a container that can be pressurized with CO2.
[0004] There remains a need for proper maintenance of sports ball repressurization without
the requirement of complicated procedures or expensive equipment.
Summary of the invention
[0005] Surprisingly, we have found a way to improve sports ball pressurization and overcome
one or more of the above or other problems of the prior art.
[0006] Accordingly, the present invention relates to sports ball pressurizing container
comprising a sealable opening and a pressure control system that comprises means to
pressurize the container and a time-controlled pressure release means. None of these
above mentioned prior art documents provides for a inflation system with a time controlled
pressure release valve. Preferably, the container comprises a pressure control system
that comprises an electronic control unit, a gas supply to pressurize the container,
a time keeping device, a time-controlled pressure release valve, a pressure gauge,
and a user interface. Preferably, the time-controlled pressure release means is connected
via an electronic control to an electronic time keeping device. Preferably, the electronic
control unit has electronic connections for data receiving of the time keeping device,
the pressure gauge, and the user interface, and wherein the electronic control unit
has electronic connections for data providing with the means to pressurize, the time-controlled
pressure release means and the user interface; and wherein the container has a gas
inflow connection with the means to pressurize and a gas outflow connection with the
pressure gauge, the time-controlled pressure release means and the safety release
valve; and wherein the container has closure means that provides for a physical closure
connection between the container and the lid to seal the container interior. Preferably,
the electronic control unit has electronic connections for data receiving with the
means to pressurize, the time keeping device, the pressure gauge, the user interface
and the closing sensor, and wherein the electronic control unit has electronic connections
for data providing with the means to pressurize, the time-controlled pressure release
means and the user interface; and wherein the container has a gas inflow connection
with the means to pressurize and a gas outflow connection with the pressure gauge,
the time-controlled pressure release means and the safety release valve; and wherein
the container has closure means that provides for a physical closure connection between
the container and the lid to seal the container interior. Preferably, the opening
is sealed with a door and a rubber seal and wherein the rubber seal is bonded to the
door and/or to the container.
[0007] The present invention further relates to a method of pressurizing at least partially
deflated sports balls by:
- (i) loading the balls into the interior of a container with a sealable opening;
- (ii) pressurizing the container interior using a pressurizing means;
- (iii) monitoring the time period of pressurization with a time keeping device; and
- (iv) lowering the pressure of the container interior with a time controlled pressure
release valve.
[0008] Preferably, the time keeping device measures the time period t
ambient during which the balls with original internal ball pressure p
original are exposed to ambient pressure p
ambient. Preferably, during step (iii), the means to pressurize the container subject the
balls to an inflation pressure p
inflation that is higher than the original internal ball pressure p
original of the balls for an inflation time period t
inflation such that:

and wherein k represents a factor of between 0.1 and 10.0.
[0009] Preferably, the inflation pressure differential (p
inflation - p
original) corresponds to the deflation pressure differential (p
original - p
ambient). Preferably, the inflation time period t
inflation corresponds to the deflation time period t
ambient. Preferably, following above step (iv), the pressure is lowered to the original internal
ball pressure p
original . Preferably, after above step (ii), the pressure supply is temporarily interrupted,
the pressure in the container is monitored with the pressure gauge and the electronic
control unit triggers an alarm when the pressure drops at a rate of at least 0.01
bar/min. According to a preferred method, the sports balls are pressurized by the
following steps:
(ia) determining the original pressure p original of the sports balls;
(ib) exposing the balls to ambient pressure p ambient;
(ic) loading the balls into the container;
(iia) determining the ambient time period t ambient that the balls were exposed to ambient pressure p ambient;
(iia) determining the inflation pressure p inflation;
(iib) pressurizing the container with the balls to the inflation pressure p inflation;
(iic) determining the inflation time period t inflation;
(iiia) releasing pressure after reaching the inflation period time t inflation;
(iiib) keeping container at original ball pressure p original for storage; and
(iiic) opening container and optionally repeat step (ia) as above.
[0010] Surprisingly, we have found that containers according to the present invention allow
for proper pressurization of sports balls, even mixtures of old and new balls. The
invention provides a convenient and flexible way of repressurization of sports balls.
Sports players will benefit in that they will less frequently be confronted with "dead"
balls amongst the sports balls that they are playing with. The invention allows sports
balls to be pressurized in batches and to similar internal pressures even mixed batches
of old and new balls. The present invention further allows for maintenance of relatively
constant pressurization of sports balls over time, each ball individually but also
the sports balls as a batch, contributing to enjoyable play over longer periods.
Brief description of the figures
[0011] Figure 1 is a schematic representation of a preferred embodiment of the container
of the present invention. Figure 2 is a schematic representation of a preferred embodiment
of the container according to the present invention. Figure 3 is a schematic representation
of a preferred electronic control scheme that may be used in the present invention.
Figure 4 is a schematic representation of a preferred flow chart that may be used
in the present invention.
Detailed description of the invention
[0012] For the purpose of the invention, the unit of pressure is bar absolute which may
also be referred to as bara or according to this invention bar. Bar absolute is zero-referenced
to complete vacuum. 1 bar is equal to 100 kPa and to 0.987atm. Another unit of pressure
is gauge bar or barg, which is zero referenced to the atmospheric pressure and thus
represents the atmospheric overpressure. Thus, a barg value is about 1 unit lower
than the corresponding bar (= bara) value. Another unit of pressure are pound-force
per square inch or psi. 1 bar is equal to approximately 14.5psi.
[0013] In one aspect, the invention relates to a sports balls pressurizing container. Examples
of such balls without inflation valve are tennis balls, squash balls, and racketball
balls. Preferably, the present invention relates to tennis balls. It is preferred
that the sports balls are made of rubber, more preferably the sports balls have a
fabric coating. The container pressurizes one or more sports balls in its interior.
Preferably, a batch of multiple balls is pressurized at the same time in the container
interior, preferably at least 3, more preferably at least 10, and preferably at most
10000, for instance between 10 and 500, or around 150 sports balls. Preferably, the
balls are put in a bag to contain dirt, gravel and ball fibers inside the bag. Preferably,
the bag is open to allow for pressure adjustment inside the bag.
[0014] Preferably, the sports ball container of the invention comprises a closing means
which is preferably a lid or a door. Preferably, the closing means comprise a hinge.
Preferably, the container comprises a closure sensor (interlock safety sensor).
[0015] In another aspect, the invention relates to a container, and particularly a sports
ball container, comprising a sealable opening which is preferably sealed with a closing
means. Pressure containers of the prior art use O-ring seals or clamped seals, but
we have found that usage of such seals may lead to pressure leakage leading to frequent
seal replacement. We have found that pressure leakage may be reduced by bonding the
seal to the door and/or to the container. It reduces the number of mechanical contact
interfaces to just one interface, and allows for much easier cleaning prior to closing
the container. Without wishing to be bound by any theory, we believe that by bonding
the seal to the door and/or to the container allows for better removal of contaminations
such as dirt, gravel and ball fibers from the seal. Such contamination may be introduced
by the sports balls loading in and unloading from the container interior. In fact,
we have found that the invention may prevent such contamination in the first place.
The invention may lead to a cleaner seal, resulting in less leakage, a better functioning
container and better pressurized sports balls.
[0016] Preferably, the seal according to this aspect of the invention is bonded to the door,
to the container, or to both. In case of two seals that for instance contact, connect
or intertwine, one seal may be bonded to the door while the other seal may be bonded
to the container. Preferably, the seal is made of rubber. Preferably, the bonded seal
is used for sports ball containers. We have found that such a bonded seal is surprisingly
effective for pressurizing balls in a container. Preferably, the bond is created by
using an adhesive that bonds the seal and the underlying surface of the door, the
container, or both (in case of two seals). To bond a rubber seal to the door and/or
container surface, preferably an adhesive is applied or in the alternative, first
a primer is applied, then a non-vulcanized rubber is applied and subsequently the
rubber seal is vulcanized.
[0017] In a further aspect, the invention relates to a container comprising a pressure control
system that comprises means to pressurize the container and a time-controlled pressure
release means. Preferably, the pressure control system comprises an electronic control
unit, also called an ecu. Preferably, the pressure control system comprises a time
keeping device. Preferably, the pressure control system comprises a pressure gauge.
Preferably, the pressure control system comprises a safety release valve. Preferably,
the pressure control system comprises a user interface. The pressure control system
may further comprise tubing, cables for electronic data exchange, and a closure sensor.
[0018] Preferably, the means to pressurize the container is by reduction of the interior
space of the container, by increase of the gas content of the container, or by a combination
thereof. The interior space may be reduced by moving one or more of the walls of the
containers inwards, for instance by screwing a cap on a container. Preferably, the
means to pressurize the container is a gas supply, using a pressurized gas tank, or
more preferably a compressor or hand pump, most preferably a compressor. Preferably,
the gas used in the present invention is Nitrogen or air, more preferably air.
[0019] Preferably, the time-controlled pressure release means increases the interior space
of the container, decreases the gas content of the container, or a mixture thereof.
The interior space may be increased by moving one or more of the walls of the containers
outwards, for instance by unscrewing a cap from a container. Preferably, the time-controlled
pressure release means is a valve. Preferably, the means is electronic. Preferably,
the means is automatic. Preferably, the pressure is reduced by opening the valve and
releasing the gas until a programmed pressure has been measured with the pressure
gauge.
[0020] Preferably, the ecu comprises one or more microcontrollers with embedded software
(i.e. a programmed microcontrollers), preferably including stored algorithms for use
in the present invention. Preferably, the ecu provides the central processing and
control unit of the electronic data for receiving and sending data in order to manage
the pressurization of the container interior, for instance by recording, setting,
maintaining, adjusting and/or terminating the pressurization of the container interior.
Power supply may contain universal line (110V/220V) power adaptor, or may be a battery.
[0021] Preferably, the time keeping device is electronic and preferably automatic. Preferably,
the time keeping device measures the time for instance in units of seconds, minutes
or hours. A preferred time keeping device is a clock. According to the invention,
the clock may be analogue, digital, mechanic and/or electronic and is preferably electronic.
Preferably, the time keeping device is driven by a quartz crystal, a source of a time
base.
[0022] Preferably, the pressure gauge is an electronic gauge, allowing for convenient interfacing
with the ecu. Preferably, the safety release valve prevents pressure of the container
interior to exceed a maximum pressure value. At higher pressures, the safety release
valve will open and release the pressure. Preferably, the closure sensor is located
in the sealing device and/or hinge bracket and registers whether the container is
physically closed and/or sealed. Preferably, the tubing allows for passage of gas
for pressurizing and/or pressure release of the container interior. Preferably, cable
wiring connects the various elements of the container and the pressure control system
to allow for electronic data exchange between the elements. Preferably, the user interface
comprises a display and control buttons. Preferably, the control buttons include a
start button. Preferably, the control buttons include a button for setting factor
k as indicated below.
[0023] Preferably, the container of the invention has the following electronic connections,
physical connections and/or flow connections. Preferably, the ecu is electronically
connected to the means to pressurize to provide input on supplying pressure to the
container and to the time-controlled pressure release means to provide input on releasing
pressure from the container. Preferably, the ecu is electronically connected to the
time keeping device to receive input on the time. Preferably, the ecu is electronically
connected to the pressure gauge to receive input on the pressure in the container.
Preferably, the ecu is electronically connected to the user interface to receive input
from the control buttons and to provide input to the display on the status of the
container for instance on pressure and time. Preferably, the ecu is electronically
connected to the closing sensor to receive input on the physical closure of the container.
Preferably, the ecu is electronically connected with a power supply.
[0024] Preferably, the means to pressurize the container is electronically connected to
the ecu and has a flow connection, preferably through tubing, with the container to
provide pressurization, preferably by providing a gas flow. Preferably, the time controlled
pressure release means is electronically connected to the ecu and has a flow connection,
preferably through tubing, with the container to release pressurization from the container.
Preferably, the pressure gauge is electronically connected to the ecu and has a flow
connection, preferably through tubing, with the container to measure the pressure
in the container interior. Preferably, the safety release has a flow connection with
the container and is able to autonomously release overpressure from the container
interior. Preferably, the closure means provides for a physical closure connection
between the container and the door to close off the container interior and an electronic
connection with the ecu to provide input to the ecu on the closure status of the door.
[0025] According to the invention, the container comprises a time controlled pressure release
means. Based on the time input from the time keeping device, on the container pressure
input from the pressure gauge, the ecu provides electronic input to the time controlled
pressure release means and controls the release of pressure from the container. The
invention allows for precise pressurization of sports balls based on precise timing
of pressure release as determined by the ecu based on various input including the
time keeping device, the pressure gauge, the closing means, and the user interface.
[0026] In a further aspect, the invention relates to a method of pressurizing at least partially
deflated sports balls by:
- (i) loading the balls into the interior of a container with a sealable opening;
- (ii) using means for pressurizing the container interior;
- (iii) monitoring the time period of pressurization with a time keeping device; and
- (iv) lowering the pressure of the container interior with a time controlled pressure
release valve.
[0027] Sports balls in step (i) may for instance be retrieved from a pressured new ball
can or for instance from the pressurization container after inflation.
[0028] To facilitate the pressurization method, the ecu preferably receives input from the
closure sensor on container closure, from the control buttons on the user interface,
and from the pressure gauge on the pressure in the container interior and provides
input to the means to pressurize the container to provide gas supply to the container
interior through the tubing. Preferably, the ecu receives input from the time keeping
device on the time and from the pressure gauge on the container interior pressure
and provides input to the time controlled pressure release means to lower the pressure
in the container interior. Meanwhile, the ecu provides electronic data on the status
of the method to the display on the user interface.
[0029] Preferably, the time keeping device and ecu monitor the ambient time period t
ambient during which the sports balls are exposed to ambient pressure p
ambient. This occurs during step (iii). Preferably, the time keeping device provides the
ecu with the time - time a - when the pressure gauge provides electronic data to the
ecu that the pressure in the container has dropped below 1.5 bar which occurs shortly
after the user has instructed the container to vent. Preferably, the time keeping
device provides the ecu with the time - time b - when the pressure gauge provides
electronic data to the ecu that the container pressure has reached above 1.5 bar which
occurs shortly after the user presses the start button on the control buttons of the
user interface. From the difference in time (b-a), the ecu determines the ambient
period time t
ambient.
[0030] The ambient pressure p
ambient may be measured using a pressure gauge or estimated, for instance at 1 bar. Usually,
p
ambient is around 1 bar, at atmospheric pressure.
[0031] Preferably, the balls of a batch have similar or equivalent original internal ball
pressure p
original, although this is not essential for the invention. Preferably, the original internal
ball pressure p
original is known, from ball factory settings, but it may also be measured or estimated. For
instance, the p
original of tennis balls is generally between 1.5 and 2.2 bar, for instance around 2 bar.
[0032] Preferably, the means to pressurize the container subjects the balls to a inflation
pressure p
inflation that is higher than the original internal ball pressure p
original of the balls. Preferably, inflation pressure p
inflation is preferably applied during above steps (ii) and (iii). Preferably, the inflation
pressure p
inflation is monitored with the pressure gauge.
[0033] Preferably, the time keeping device and ecu monitor and determine the inflation time
period t
inflation, starting from the time that the container has reached p
inflation at the beginning of step (iii) and until the time-controlled pressure release means
starts lowering the pressure at the end of step ii). The pressure gauge provides electronic
data to the ecu that the inflation pressure p inflation has been reached. The ecu
registers the time - time c - as provided by the time keeping device. The ecu determines,
preferably with any of its algorithms (and more preferably using the algorithm as
provided below) the inflation time period t
inflation. With time input from the time keeping device, the ecu registers the time period
of time c + t
inflation and instructs the time-controlled pressure release means to release the pressure
from the container interior.
[0034] The present invention relates to a time-controlled pressure release means which,
by monitoring the pressurization time, allows for precise pressurization of sports
balls. Preferably, sports balls are pressurized to their original internal pressure
p
original or sometimes - but less preferred - close to their original internal pressure. The
time controlled pressure release means is preferably controlled by the ecu and releases
the pressure based on the instructions from the ecu which works in conjunction with
the other devices as indicated.
[0035] After inflation, the pressure in the container is preferably lowered to the original
internal ball pressure p
original for storage of the sports balls. This occurs in above step (iv).
[0036] When inflating, the sports balls are preferably subjected to an inflation pressure
p
inflation for an inflation time period t
inflation such that (algorithm):

wherein factor k represents a factor that is preferably larger than 0.1, more preferably
larger than 0.5 and preferably lower than 10.0, more preferably lower than 2.
[0037] Preferably, factor k can may determined by the user with the buttons on the user
interface to customize the internal pressure of the sports ball. This factor can be
determined empirically. If the user chooses factor k equals 1, then the sports balls
will be inflated to the previous original ball pressure p
original, a lower value for k leads to softer balls while a higher value for factor k leads
to harder balls. By choosing k, the user can take other aspects such as court type,
personal preference, weather and altitude into account when deciding on the ball pressure.
For instance, on hardcourt, tennis balls often lose felt and become faster. Under
such circumstances, factor k may be set to a value less than 1. If a trainer finds
after several weeks of play that the balls become too fast, he can decrease the setting
of factor k on the user interface. On the other hand, on other types of courts the
tennis ball felt may become fluffy, slowing down the ball due to excess wind resistance.
Under such circumstances, factor k may be set larger than 1.
[0038] A sports ball or a set of sports balls is generally exposed to p
ambient for less than 24 hours, therefore allowing for repressurization during the remainder
of the day, during the night, or even in the subsequent days.
[0039] Preferably, the inflation pressure p
inflation in the container is at least 2.3 bar, more preferably at least 2.5 bar and preferably
at most 5 bar and more preferably at most 4 bar.
[0040] To prevent effects of non-linearity in the permeability, it is preferred that inflation
pressure differential (p
inflation - p
original) is equal to the deflation pressure differential (p
original - p
ambient). Preferably, the inflation time period t
inflation is set such to correspond to the deflation time period t
ambient.
[0041] In addition, p
inflation is preferably kept low to allow for a lower cost pressure tank and compressor and
to prevent collapse of the sports ball under inflation pressure. An important aspect
of this invention is that the balls are reinflated preferably every night so that
the ball has sufficient remaining pressure to prevent collapse under inflation pressure.
Preferably, the inflation time period t
inflation is at least 1 hours, more preferably at least 3 hours, and preferably at most 24
hours and more preferably at most 12 hours.
[0042] Generally, the time the sports balls are in play is shorter than 12 hours. In that
case, a preferred inflation pressure is around 3 bar, as this provides an inflation
pressure differential of 1 bar which is equal to the deflation pressure differential
(of about 2 bar p
original minus 1 bar p
ambient) and the inflation time period t
inflation can be kept at the same length as the ambient time period t
ambient during which the balls were exposed to ambient pressure p
ambient. Any additional time after t
inflation and before opening of the container, the sports balls are preferably stored at p
original to optimize internal sports ball pressure. For simplicity 2 bar may be used
as an example.
[0043] A preferred method according to the invention relates to a method of pressurizing
at least partially deflated sports balls by:
(ia) determining the original pressure p original of the sports balls;
(ib) exposing the balls to ambient pressure p ambient;
(ic) loading the balls into the container;
(iia) determining the ambient time period t ambient that the balls were exposed to ambient pressure p ambient;
(iia) determining the inflation pressure p inflation;
(iib) pressurizing the container with the balls to the inflation pressure p inflation;
(iic) determining the inflation time period t inflation;
(iiia) releasing pressure after reaching the inflation time period t inflation;
(iiib) keeping container at original ball pressure p original for storage; and
(iiic) opening container and optionally repeat step (ia) as above.
[0044] The method of the invention may also provide for the option of opening the container
before the inflation time period t
inflation has ended, for instance when the sports balls are needed in another unexpected game
challenge. In that case, the remaining inflation time may be added to the next inflation
time, of course adjusting for any differences in inflation pressures p
inflation and using the algorithm provided.
[0045] The present invention provides for proper inflation of sports balls, also covering
a mix of old and new balls. Without wishing to be bound by any theory, old balls may
generally deflate quicker as gas diffuses faster through the worn-out rubber of the
ball as compared to new balls. However, at the same time, old balls may generally
inflate more quickly as well because gas diffuses after through the worn-out rubber
into the ball as compared to new balls. We have surprisingly found that mixes of old
and new balls may be properly inflated with the present invention.
[0046] In another aspect, the present invention relates to a method of monitoring pressure
leakage from a container wherein the container is pressurized, the pressure supply
is temporarily interrupted, the pressure in the container is monitored with a pressure
gauge and an alarm is triggered when the pressure drops at or above a certain rate.
Preferably, an ecu triggers the alarm. Preferably, the rate of pressure drop is at
least 0.01 bar/min, more preferably at least 0.05 bar/min. Preferably, the pressure
supply is interrupted for a period of at least a few seconds, more preferably 30 seconds
and preferably at most 5 minutes, more preferably at most 2 minutes, for instance
1 minute.
Detailed description of the figures
[0047]
Figure 1 schematically shows a three dimensional illustration of a container according
to the invention wherein the opening of ball container 102 with stand 110 can be sealed
with closing means lid 101 to which rubber seal 103 is bonded. Lid 101 connects with
hinge pin 106 which is locked with hinge pin interlock 107 and is part of hinge bracket
105. User interface 108 is connected to control cable 109
Figure 2 schematically shows a cross section of a preferred sports ball container
according to the invention. Tennis balls 204 rest on bottom 203. Compressor 201 is
placed underneath at interior bottom 203 together with pressure control unit 202 which
comprises an electronic pressure gauge, an electronic clock as time keeping unit,
an electronic time-controlled pressure release valve, tubing, and an ecu.
Figure 3 schematically shows a preferred electronic control scheme of the present
invention. Double lines represent gas flow direction, single lines represent electronic
information flow with the arrows indicating the flow direction, and the dashed line
represents the physical connector between the interlock sensor and the lid hinge pin.
Power input from power supply 303 is provided to electronic control unit 301 which
is provided with electronic input on lid closure from lid safety lock 310. Electronic
input on time is provided to the ecu by electronic time keeping device clock 302 and
electronic input on pressure inside container 304 from pressure gauge 307. Electronic
control unit 301 exchanges electronic data with user interface 309 which consists
of a display and control buttons.
Electronic control unit 301 provides electronic input to compressor pump 305 to control
gas supply to container 304. Ecu 301 provides electronic input to time-controlled
pressure release valve 306 to control gas release from container 304. Pressure gauge
307 measures the pressure in container 304 and provides electronic data on pressure
to electronic control unit 301. Safety release valve 308 opens above 3.2 bar and releases
the gas, maintaining the pressure in container 304 at maximum 3.2 bar. Container 304
physically interlocks with lid safety interlock 310 to seal the opening of container
304.
Figure 4 schematically shows an example of a preferred flow diagram wherein a rectangular
box represents a user action and an oval box represents an ecu action. Starting at
the top, the user opens the lid by pressing. The ecu opens the release valve until
pressure gauge indicates the atmospheric release pressure of 1 bar and subsequently
registers the time 1. The user may then remove the sports balls, plays a game, ends
the game, places the balls in the container, closes the lid of the container and presses
the start control button on the user interface. The ecu registers the time 2. The
ecu starts the compressor until the pressure gauge indicates that the inflation pressure
of 3 bar has been reached and maintains the pressure in the container at 3 bar for
time period (time 2- time 1). Subsequently, the ecu opens the release valve until
the pressure gauge indicates pressure of 2 bar as storage pressure for the sports
balls. Subsequently, the flow diagram continues at the top.
The following non limiting example is provided
Example
[0048] A tennis teacher starts at 9 am (time a) with the opening of the container that was
pressurized at a storage pressure of 2 bar which is equivalent to the original ball
pressure p
original. Before opening, the container first depressurizes using the pressure release valve
to ambient pressure p
ambient of 1 bar (atmospheric pressure). The ecu in combination with the time keeping device
registers a time of 9am when the pressure gauge indicates 1 bar. The teacher removes
the sports balls and replaces them in the container at the end of the day at 5pm (time
b). He closes the lid and presses the start button on the user interface. Slightly
after 5pm, using the time keeping device the ecu registers through the pressure gauge
that the pressure in the container has reached 1.5 bar and registers the end of ambient
time period t
ambient. The teacher sets factor k to 1. The ecu instructs the pressurizing means to increase
the pressure of the container to an optimal inflation pressure p
inflation of 3 bar considering that inflation pressure differentials (p
inflation - p
original) and deflation pressure differential (p original - p ambient) are equal to prevent
effects of non-linearity in the permeability. Using the above algorithm (wherein t
inflation =1*8*(2-1)/(3-2) = 8 hours), the ecu instructs, under guidance from the
time keeping unit, the time controlled release means to release pressure at 1am the
next day to the storage pressure p
original of 2 bar. The next day, the tennis teacher can again use properly inflated balls
for an enjoyable tennis training.
1. Sports ball pressurizing container comprising a sealable opening and a pressure control
system that comprises means to pressurize the container and a time-controlled pressure
release means.
2. Container according to claim 1, wherein the container comprises a pressure control
system that comprises an electronic control unit, a gas supply to pressurize the container,
a time keeping device, a time-controlled pressure release valve, a pressure gauge,
and a user interface.
3. Container according to claim 1, wherein the time-controlled pressure release means
is connected via an electronic control to an electronic time keeping device.
4. Container according to claims 1-3, wherein the electronic control unit has electronic
connections for data receiving of the time keeping device, the pressure gauge, and
the user interface, and wherein the electronic control unit has electronic connections
for data providing with the means to pressurize, the time-controlled pressure release
means and the user interface; and wherein the container has a gas inflow connection
with the means to pressurize and a gas outflow connection with the pressure gauge,
the time-controlled pressure release means and the safety release valve; and wherein
the container has closure means that provides for a physical closure connection between
the container and the lid to seal the container interior.
5. Container according to claims 1-4, wherein the opening is sealed with a door and a
rubber seal and wherein the rubber seal is bonded to the door and/or to the container.
6. Method of pressurizing at least partially deflated sports balls by:
(i) loading the balls into the interior of a container with a sealable opening;
(ii) pressurizing the container interior using a pressurizing means;
(iii) monitoring the time period of pressurization with an time keeping device; and
(iv) lowering the pressure of the container interior with a time controlled pressure
release valve.
7. Method according to claim 6, wherein the time keeping device measures the time period
t ambient during which the balls with original internal ball pressure p original are exposed to ambient pressure p ambient.
8. Method according to claims 6-7, wherein, during step (iii), the means to pressurize
the container subject the balls to a inflation pressure p
inflation that is higher than the original internal ball pressure p
original of the balls for an inflation time period of t
inflation such that:

and wherein k represents a factor of between 0.1 and 10.0.
9. Method according to claim 8, wherein the inflation pressure differential (p inflation - p original) corresponds to the deflation pressure differential (p original - p ambient).
10. Method according to claim 8, wherein the inflation time period t inflation corresponds to the deflation time period t ambient.
11. Method according to claims 6-10, wherein, following step (iv), the pressure is lowered
to the original internal ball pressure p original.
12. Method according to claims 6-11, wherein after step (ii), the pressure supply is temporarily
interrupted, the pressure in the container is monitored with the pressure gauge and
the electronic control unit triggers an alarm when the pressure drops at a rate of
at least 0.01 bar/min.
13. Method according to claims 6-12, wherein the sports balls are pressurized by the following
steps:
(ia) determining the original pressure p original of the sports balls;
(ib) exposing the balls to ambient pressure p ambient;
(ic) loading the balls into the container;
(iia) determining the ambient time period t ambient that the balls were exposed to ambient pressure p ambient;
(iia) determining the inflation pressure p inflation;
(iib) pressurizing the container with the balls to the inflation pressure p inflation;
(iic) determining the inflation time period t inflation;
(iiia) releasing pressure after reaching the inflation time period t inflation;
(iiib) keeping container at original ball pressure p original for storage; and
(iiic) opening container and optionally repeat step (ia) as above.