U.S. patent application number 09/989473 was filed with the patent office on 2002-05-30 for hydrocarbon sensing apparatus.
Invention is credited to Chuang, Hsu-Chen.
Application Number | 20020063629 09/989473 |
Document ID | / |
Family ID | 32070487 |
Filed Date | 2002-05-30 |
United States Patent
Application |
20020063629 |
Kind Code |
A1 |
Chuang, Hsu-Chen |
May 30, 2002 |
Hydrocarbon sensing apparatus
Abstract
An apparatus for monitoring presence of hydrocarbon-based fluid
is disclosed. It includes a body and a sensing cable mounted on the
body in a wave-like shape, thus forming a plurality of sensing
sections for detecting a layer of hydrocarbon on water. When
contacting hydrocarbon, each of the sensing sections generates a
signal and the signals add up before transmission to a signal
receiver through a signal line.
Inventors: |
Chuang, Hsu-Chen; (Taipei,
TW) |
Correspondence
Address: |
Connolly Bove Lodge & Hutz LLP
P.O. Box 2207
Wilmington
DE
19899-2207
US
|
Family ID: |
32070487 |
Appl. No.: |
09/989473 |
Filed: |
November 20, 2001 |
Current U.S.
Class: |
340/632 ;
340/603 |
Current CPC
Class: |
Y10T 436/21 20150115;
Y02A 20/20 20180101; G01N 33/1833 20130101; G01N 33/1886 20130101;
G01N 27/126 20130101; Y02A 20/206 20180101 |
Class at
Publication: |
340/632 ;
340/603 |
International
Class: |
G08B 017/10 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 24, 2000 |
TW |
89220684 |
Claims
1. An apparatus for monitoring presence of hydrocarbon-based fluid
comprising a body and a sensing cable mounted on the body in a
wave-like shape, thus forming a plurality of sensing sections for
detecting a layer of hydrocarbon on water; wherein when contacting
hydrocarbon, each of the sensing sections generates a signal and
the signals add up before transmission to a signal receiver through
a signal line.
2. The apparatus of claim 1, wherein the sensing cable is formed of
conductive polymer including a first resistance in the air or water
and a second resistance larger than the first resistance when
contacting hydrocarbon.
3. The apparatus of claim 1, wherein the body is a buoy for
floating on water.
4. The apparatus of claim 3, wherein the buoy is shaped like a
drum.
5. The apparatus of claim 3, further comprising a steel cable
connected between the buoy and a proper stationary position with
respect to the ground.
6. The apparatus of claim 3, wherein the buoy is shaped like a
cylinder.
7. The apparatus of claim 6, wherein the sensing cable is helically
wrapped around the buoy.
8. The apparatus of claim 1, further comprising a plurality of
hooks mounted on a periphery of the buoy for engagement with
various portions of the sensing cable, thus forming the wavelike
shape of the sensing cable.
Description
BACKGROUND OF INVENTION
[0001] 1. Field of Invention
[0002] The present invention relates to a hydrocarbon-sensing
apparatus and, more particularly, to a conductive polymer-based
hydrocarbon-sensing apparatus including multiple sensing sections
for contacting a layer hydrocarbon.
[0003] 2. Description of Related Art
[0004] Pollution of reservoirs, rivers, or groundwater has new
become a global problem. Such pollution may be caused by illegally
dumping waste into water source. Moreover, oil may leak from tanks
or pipes broken in an earthquake, for example. Thus, severe
contamination of environment occurs.
[0005] Hydrocarbon-based fluid such as gasoline or diesel has a
specific gravity smaller than that of water. Therefore,
hydrocarbon-based fluid tends to float on water. When tanks that
contain hydrocarbon-based fluid are located on the ground for some
time, the hydrocarbon-based fluid is very likely to leak from the
tanks. Hydrocarbon-based fluid that leaks from a tank may penetrate
the ground so as to float on groundwater. Various devices have been
devised for detecting contamination of groundwater caused by
hydrocarbon fluid. Such devices can be found in U.S. Pat. Nos.
4,131,773, 4,223,552, 4,434,650, 4,563,674, 5,264,368, 5,444,383
and 5,514,338.
[0006] FIG. 1 shows a conventional hydrocarbon leak sensor
incorporating a probe P. A portion of probe P is immersed in a well
to be monitored and an upper end of probe P is fixed onto the wall
of the well. Probe P incorporates a petroleum sensor made of
conductive polymer in the form of a cable, for example, AMC-5016
(1932TC) made and sold by a Canada-based company, Armstrong
Monitoring Corporation. The resistivity of such petroleum sensor is
about several K.OMEGA./m in the air or water and rises dramatically
to about 20 M.OMEGA./m when such petroleum sensor contacts
hydrocarbon or petroleum. Rise in resistivity of such petroleum
sensor can be taken as presence of hydrocarbon or petroleum. The
resistance (the unit is .OMEGA.) of probe P rises at a lower rate
and to a smaller extent as a shorter section of probe P contacts
hydrocarbon. In practice, probe P can be used to detect presence of
a layer of hydrocarbon as thin as 0.8 mm. The rise of the
resistance of probe P is too small to recognize when probe P
contacts a layer of hydrocarbon thinner than 0.8 mm. Therefore,
probe P cannot sense hydrocarbon leak or spill at an early stage.
Furthermore, when leaking or spilling at a low flow rate, due to
vaporization, hydrocarbon may not form a layer thick enough for
probe P to sense. In other words, it is unlikely to be able to
detect a leak or spill before significant damage has occurred.
Moreover, a hydrocarbon layer on groundwater cannot be sensed when
the groundwater surface rises above the upper end of probe P or
when the groundwater surface descends below a lower end of probe P.
To overcome this drawback, a lengthened probe is required. However,
this increases cost and limits its applications.
[0007] Thus, it is desirable to provide an improved hydrocarbon
sensor in order to overcome the above-mentioned drawbacks
encountered in prior art.
SUMMARY OF INVENTION
[0008] It is an objective of the present invention to provide an
apparatus for monitoring presence of hydrocarbon-based fluid
wherein a sensing cable is provided in a wave-like arrangement.
Thus, the sensing cable includes a number of sensing sections for
contacting a layer of hydrocarbon-based fluid on the water surface.
When contacting a layer of hydrocarbon-based fluid, the sensing
sections generate a corresponding number of signals that add up to
increase the signal intensity. A layer of hydrocarbon-based fluid
can thus be sensed by means of the sensing cable even it is very
thin. That is, the present invention can warn of hydrocarbon leak
at an early stage or at a low flow rate so that an appropriate
action can be taken before significant damage is made.
[0009] It is another objective of the present invention to provide
an apparatus for monitoring presence of hydrocarbon-based fluid
wherein a sensing cable is provided on a buoy for floating on the
water surface. Thus, it is assured that the sensing cable always
contact a layer of hydrocarbon-based fluid on the water surface no
matter how the water surface changes.
[0010] To accomplish the above objects and features, the apparatus
of the present invention comprises a buoy for floating on the water
surface and a sensing cable made of conductive polymer. The sensing
cable is mounted on a periphery of the buoy in a wavelike shape,
thus forming a plurality of sensing sections for contacting a layer
of hydrocarbon-based fluid on the water surface. When contacting a
layer of hydrocarbon-based fluid, a signal is generated in each of
the sensing sections, and the signals add up before transmitting to
the monitoring and warning unit through the signal line. By
utilizing this, a sensitivity of a hydrocarbon-sensing apparatus is
significantly increased according to the present invention.
[0011] The above and other objects, features and advantages of the
present invention will become apparent from the following
description taken with the attached drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a side view of a conventional hydrocarbon-sensing
device;
[0013] FIG. 2 is a perspective view of a first embodiment of the
hydrocarbon-sensing apparatus according to the present
invention;
[0014] FIG. 3 is a cross-sectional view of a buoy and a sensing
cable of FIG. 2;
[0015] FIG. 4 is a side view showing the buoy and a portion of the
sensing cable in different positions as the water surface
changes;
[0016] FIG. 5 is a perspective view showing another configuration
of the hydrocarbon-sensing apparatus wherein a signal line includes
a helical section for fluctuating on the water surface in a
monitoring well;
[0017] FIG. 6 is a side view of a second embodiment of the
hydrocarbon-sensing apparatus according to the invention;
[0018] FIG. 7 is a perspective view of a buoy and a sensing cable
of FIG. 6; and
[0019] FIG. 8 is a side view showing the buoy and a portion of the
sensing cable in different positions as the water surface
varies.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0020] FIGS. 2 to 5 show a first embodiment of a
hydrocarbon-sensing apparatus made in accordance with the present
invention. The apparatus includes an essential component, sensing
cable 12. In the preferred embodiments, sensing cable 12 is
AMC-5016 (19932TC) manufactured and sold by a Canada-based company,
Armstrong Monitoring Corporation, and therefore is not described in
detail for brevity. The resistivity of sensing cable 12 is about
several K.OMEGA./m in the air or water and rises dramatically to
about 20 M.OMEGA./m when sensing cable 12 contacts hydrocarbon. The
resistance (its unit is .OMEGA.) of sensing cable 12 rises at a
lower rate and to a smaller extent as a shorter section of sensing
cable 12 contacts hydrocarbon. In practice, sensing cable 12 can be
used to detect presence of a layer of hydrocarbon as thin as 0.8 mm
if it includes only one section in contact with the layer of
hydrocarbon. When a layer of hydrocarbon gets thinner than 0.8 mm,
the rise of the resistance of sensing cable 12 is too small to
recognize. To achieve a highly sensitive hydrocarbon-sensing
apparatus, sensing cable 12 is arranged in a novel manner in
accordance with the present invention to be described in
detail.
[0021] The apparatus of the present invention includes a drum-like
buoy 10 for floating on the water surface. A number of hooks 11 are
provided on the periphery 100 of buoy 10 in order to hook sensing
cable 12, thus securing sensing cable 12 to buoy 10 and making
sensing cable 12 in a wavelike shape. On a top of buoy 10, two ends
of sensing cable 12 are connected with a contact terminal 13. A
signal line 17 is connected between contact terminal 13 and a
remote monitoring and warning unit 19.
[0022] It is clearly shown in FIG. 4 that a number of sensing
sections 120 of sensing cable 12 can contact a layer of hydrocarbon
on the water surface due to the wavelike shape of the sensing cable
12 mounted on periphery 100 of buoy 10. Thus, when contacting
hydrocarbon, each sensing section 120 produces a signal
representative of the rise of the resistance. The signals
respectively generated in sensing sections 120 add up so as to
increase a total intensity (i.e., amplified), thus significantly
increasing sensitivity of hydrocarbon sensing. Accordingly, even a
layer of hydrocarbon (or petroleum) is less than 0.8 mm thick (0.1
mm in practice), the increase of the resistance of the entire
length of sensing cable 12 is still obvious in accordance with the
present invention. Such multiple sensing section arrangement of the
present invention can alert about leak or spill at an early stage
or at a low flow rate promptly by monitoring and warning unit 19
detecting a significant change of the resistance of sensing cable
12. Therefore, appropriate actions can be taken before significant
damages occur.
[0023] When used in open water, the apparatus of the present
invention is vulnerable to strong wind and water flow. The signal
line 17 would be easily torn. To resist such strong wind and water
flow, a steel cable 15 is used. Steel cable 15 is connected between
the top of buoy 10 and a ring 18 attached to the ground. In
addition, steel cable 15 is bound with a section of signal line 17.
Thus, possible forces exerted by strong wind and water flow are
taken by steel cable 15 instead of signal line 17.
[0024] When used in still water such as in a well where a float
goes up and down together with the water surface but does not drift
due to no strong wind or water flow, steel cable 15 is not
necessary. FIG. 5 shows another configuration without use of steel
cable 15. In this configuration, signal line 17 includes a helical
section for providing elasticity in a vertical direction for
adjusting a vertical distance between upper and lower ends of
signal line 17 to a smallest possible value.
[0025] It is further noted that the provision of monitoring and
warning unit 19 is optional. In an alternative configuration,
monitoring and warning unit 19 is replaced with a signal receiver
(not shown) provided on the ground near the location of fluid to be
monitored. The signal receiver unit may be further connected to
monitoring and warning unit 19.
[0026] Moreover, signal received from sensing cable 12 is sent to a
remote monitoring station via the signal receiver unit through
wireless means or fiber-optic (not shown).
[0027] FIGS. 6 to 8 show a second embodiment of the
hydrocarbon-sensing apparatus constructed in accordance with the
invention. The differences between second and first embodiments are
detailed below. Buoy 20 is an elongate hollow cylinder or bar. A
bracket 26 is provided across a river or other waterway. Two steel
cables 25 each have one end secured to bracket 26 and another end
secured to one end of buoy 20. A sensing cable 12 is helically
wrapped around buoy 20. A plurality of spaced hooks 21 are provided
on a periphery of buoy 20 for hooking a corresponding number of
sections of sensing cable 12, thus securing sensing cable 12 to
buoy 20. Two ends of signal line 17 are coupled to two ends of
sensing cable 12 directly and then connected to a monitoring and
warning unit 19 or a signal receiver unit (not shown). This
embodiment has the same effect as the first embodiment mentioned
above and the same components or portions as the first one
embodiment are given the same reference numbers for easy reference
thus the related descriptions are omitted.
[0028] It is noted that alternatively, for forming a wavelike shape
of sensing cable 12 on the periphery (100, 200) of the buoy (10,
20), a continuous wavelike recess (not shown) may be defined in the
periphery (100, 200) of the buoy (10, 20) for mounting the sensing
cable (12) thereon. Therefore, hooks 11 or 21 are not necessary
elements in accordance with the present invention and can be
omitted in other embodiments.
[0029] While the invention herein disclosed has been described by
means of specific embodiments, numerous modifications and
variations could be made thereto by those skilled in the art
without departing from the scope and spirit of the invention set
forth in the claims.
* * * * *