Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE
Wave-Powered Ocean Profiler
FIELD OF THE INVENTION
This invention relates to a wave-powered apparatus for collecting
oceanographic profile data.
BACKGROUND OF THE INVENTION
Time series profiles of salinity and temperature of the upper layers of the
ocean are useful for the study of valious ocean conditions such as the variation Or
ocean currents. Various types of oceanographic profilers have been used or
proposed to measure ocean parameters at diffelent depths.
A number of prior profilers involve moving the sensing instrument up and
down along a moored line. Many of these prior devices operate by changing the
buoyancy for each c~cle of operation. An example of such a device is disclosed iU.S. Patent 3,927,~62 which uses a plurality of gas generators wherein one gas
generator is utilized to vary buoyancy for each cycle of ascent and descent.
One of the difficulties with plesent plofilers is that considerable stored
energy, in the profilel is required to repeatedly change buoyancy, or otherwise
raise and lower the instrument, over many cycles of operation.
For the ocean culrent variation studies refelred to above, it would be
desirable to have a high resolution oceanographic profiler that can operate
lln~tt~nd( d for long periods of time, such as two yeals or longer, and be capable
of daily operation to a depth of 2,000 m.
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SUMMARY OF THE INVENTION
An object of the present invention is to provide an apparatus for collecting
O~ profile data that requires little stored energy and can be used to
operate l~n ~tten~led for relatively long periods of time.
It has been found that oceanographic plofile data can be obtained by ~
device that utilizes wave energy to convey the plofiler iu~llu~ up and down.
The present invention provides a wave-powered ocean profiler, ~ illg.
an - UIII~IIL for collecting oceanoglapllic plofile data; a buoyant member for
riding the waves on a body of watel; a line suspended from a lower end of the
buoyant member; a line traversing assembly operatively disposed on the line for
supporting the ill~ll ull~lll and conveying the instrument along the line; said
traversing assembly including a disengagable one-way clutch, operative, while
engaged, to allow travel incrementally along the line in one direction as the line
rises and falls under the action of waves, and to prevent travel along the line in
the opposite dilection; and actuating means for tlle one-way clutch, responsive to
a condition l~ se~ldlive of a desiled travel limit of the traversing assembly
along the line, and operative for selectively engaging or disengaging the one way
clutch.
BRIEF DESCRIPTION OF THE DRAWING~
Fig. 1 is a schematic l~ se..ldlion of the oce~r.~apl.ic plofiler of the
present invention.
Fig. 2 is an enlarged view of the ill~llulll~lll assembly shown in Fig. 1.
Fig. 3 is an enlarged view of a portion of the instrument assembly
illustrating details of one embodiment of the one-way clutch and clutch actuatin~
I..r. 1,~1~;'.-ll
Figs. 4(a), (b), and (c) show the one-way clutch of Fig. 3 in the engaged
position, disengaged position, and locked position, respectively.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to Fig. 1, the present invention comprises a buoyant
member 1 having suspended therefrom a line 2. Operatively associated with the
line is a line traversing assembly 6 for conveying instrument components for thea~q~liciti~n and ~ ion of pl-oSle data.
With reference to Fig. 2, the profile ill~llL..~ U..I~JU.._llt~ 10 include
profile data sensing and recording means 11, battery 12, and electronic
. 13 for data processing and ~ ;vil and may include a computer
15 for system control.
As illustrated in Fig. 2, the traversing assembly 6 comprises a sealed
enclosure 16 that encloses a numbel- of the system ~vlllpu~ . In the pleferred
embodiment of the invention, the enclosure 16 is designed such that the line
traversing assembly 6 has a specific g~avity diffelent from that of the water toprovide either positive or negative buoyancy. For example, positive buoyancy canbe achieved by a sealed enclosure 16 containing air or gas.
In the embodiment illustrated in ~igs. 1 to 3, the ill~ll Ulll~,l.. traversing
assembly 6 has a single riic~ng~ c one-way clutch 8, operative, while engaged,
to allow travel i...~ dlly along the line 2 in a direction against the buoyancy
force of the assembly as the buoyant membel 1 and line 2 rises and falls under
the action of waves, and prevents travel along the line in the opposite direction.
In this embodiment the buoyancy force is utili~ed to retuln the assembly 6 to the
original position, by disengaging the clutch from the line 2.
~s best seen in Fig. 3 and 4, the one-way clutch 8 is selectively engaged or
rlic~ng;l~ed by actuator 17 by means of alm 18. When disengaged, the assembly
moves freely in the direction of the buoyancy force. Figs. 4(a), (b), and (c) show
the one-way clutch of Fig. 3 in the engaged position, disengaged position, and
locked position respectively.
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Fig. 3 shows details of one embodiment of an actuator mechanism 17
which includes an arm 18, drive motor 19 and interrr~nr~in~ motion translating
~ 20. It will be understood that othel forms of Inr~ could be
used.
Activation of the one-way clutch by actuator 17 may be made responsive to
a condition ~ selll~ive of a desired travel position of the traversing assembly 6
along the line, with the use of suitable control means. The control means may,
for example, include a marker, or mal*ers, on the line l~ i,.g travel limits,
and a suitable marker sensor, or the contlol means may be made responsive to
the position by suitable depth sensing means. The control means may include
suitable computer 15. Altelnatively, activation of the one-way clutch may be
activated entirely, or partly, by mechanical means, for example with the use of
stoppers 4, defining upper and lower travel limits.
The c~,.,.p~ ~t referled to as a "one-way clutch" helein, may take any of
various forms which allows the instrument assembly 6 to tlavel along the line il,
one direction only, when engaged, and to allow fiee travel when disengaged. A
device found to be suitable is known as a "Chicago Clamp" which has been used atsea for many years. Other devices could be used, such as a collet.
The one-way clutches could be contlolled mechanically, for example, with
the use of upper and lower mechanical stoppels which could provide that th~
.i assembly cycles continuously between the stoppers. For greater
~dexibility the one-way clutches are pleferably contlolled by a computer 15 which
facilitates greater flexibility in cycle timing and/or for transfer of data.
Since there is the possibility of wear occurring whele the clutch locks
repeatedly onto the line, it may be desirable to introduce a "dither" command intc
the locking cycle.
.
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The assembl~ 6 is shown provided witll bumpers 14 which are adapted to
contact with stoppers or bumpers 4 disposed at the upper and lower travel limitsof the line 2, as shown in Fig. 1.
Preferably the line 2 will be provided with some form of tightening means
to provide that the line is taut and moves up and down with the buoyant member
1, as it rides up and down with the waves S. This can be achieved by the use of
suitable ballast 3, as shown in Fig. 1, or may be achieved by the use of sufficient
mass of the line 2, itself. Alternatively, an elastic member my be interconnected
between the lower end of the line 2 and the ocean bottom.
The system may be anchored in the desired location with a suitablc
anchor 8 shown attached to the ballast 3, or be allowed to drift freely.
The buoyant member may be made up of a group of intel-u. --trd bouys,
rather than a single unit as illustrated. Such an arrangement can be advantageous
for ~tt~ntl~tin~ motion of the line, and hence the travelsing assembly, in beavylS weather. Protection in heavy weather for the tlavelsing assembly and/ol
illD~lU~ .~11 D can also be obtained by ill~ol~J~Jla~;ng suitable suspension and/or
damping means.
In operation, the action of ocean waves moves the buoyant member 1 up
and down. The line 2 which is attached to the buoyant member 1, also moves up
and down, along with any attached ballast 3. The instrument assembly 6 is
attached to the line 2 by means of a one-way clutch 8. With the one-way clutch
engaged, by actuator 18, as shown in Fig. 4(b), the assembly is pulled along with
the line as it moves in one direction, while allowing the line to slide relative to the
iUD~lUlUCill~ assembly 6 in the opposite direction. With lepeated up and down
motion of the line, the ;IIDLII~ Will advance incrementally in one directio
determined by the selected orientation of the one-way clutch 8.
For return to the original position, the one-way clutch is disengaged fiom
the line as shown in Fig. 4(b), returning fol example, by utilizing the buoyancy
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force of the traversiDg assembly. When no advancing motion of the assembly is
desired, such as when ll g data, the one-way clutch can be locked as
shown in Fig. 4(c)
Profile data can be recorded by the i~ luul during descent, ascent, or
both directions. In an embodiment that utilizes buoyancy for ascent, data
during the ascent may be preferably for a number of reasons. With a
suitable buoyancy force, the ill~llulllelll can be made to rise rapidly so that power
to the sensors and data logger need be supplied for a shorter time. Furthermore,the ascent will be smoother and more consistent. Also, ~l,u~ ;on of data to
the surface buoy can be achie~ed with a less powerful transmitter.
Data recorded by the i .llulll~ can be collected and/or transmitted by
kDown telemetering tl~nhniq~ For example, an acoustic ~ " system
can be used to transfer data to the surface buoyant member from which it can be
transmitted elsewhere via satellite.
For proper operation the instrument assembly must be provided with
sufflcient inertia and/or ll~dlu(lyllalllic drag to ensure that the traversing assembly
does l~ot follow the line in both dilections of the up-down cycle of the line. The
h~dludyllalll;c drag of any ballast used should be as low as possible so that it and
the liDe moves in concelt with the buoyant membel.
In the embodiment illustrated, utilizing one one-way clutch, when th~
assembly reaches a predetermined position the one-way clutch is disengaged by
actuator 18 (see Fig. 4(b) so that the instrument assembly is free to travel in the
directioD determined by its buoyancy. In anothel emhodiment, wherein two one-
way clutches are employed, the actuator arm 18 revelses the cr.6~.6~ l-l or
/lic~n~ment status of each clutch.
As indicated above, the ill~LIulll.,.it assembly can have either positive or
negative buoyancy. In the former case, the action of the waves is used to drive
the assembly dowDward while the buoyancy folce can be utilized to bring the
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assembly up to the upper position. In the later case, the action of the waves isused to drive the assembly upward while the negative buoyancy force can be
utilized to bring the assembly down to the lower position.
In another embodiment of the invention, in wllich the traversing assembly 6
has sl~hstAnhz~lly neutral buoyancy, the assembly employs two one-way clutches. I
this; ~odiu.~ one clutch would be engaged while the other is tliC~n~Ag~d for
each direction of travel, and both clutches would be reversed for the opposite
direction of travel.
Since the power for raising and lowering the ill;,llu~ l is provided by
wave energy, the plesent profiler can be made to operate unattended fol relatively
long periods of time. Still longer operation can be obtained by utilizing ocean
wave, current, wind or solar energy for chalging a battely for the electlonic
-ol~ used for data acquisition and lld~ iOll and system control.
E:xample
A prototype similal to that illustrated in the dlawings was constructed and
tested. The device was provided with a single one-way clutch to drive the
instrument assembly downward under the action of waves, and used positive
buoyancy to retuln the instrument to the surface. The i.l~l-ull,~ assembly was
2.24 m long, 0.26 m in diameter, had a mass of 100 kg, and a positi~e buoyancy of
2.27 kg. The tests were run on a buoy/mooring which was forced at 0.43 hz witl
peak to peak amplitude of 0.24 m by the waves. These values were determined by
doing a spectral analysis of the data obtained by a motion sensing i..~llu~Clll
attached to the buoy. The waves pl-oduced a descent speed of about 12 to 14
m/min. The ascent speed, under the buoyancy force with one-way clutch
disengaged, was 30 m/min.
