U.S. patent application number 11/396048 was filed with the patent office on 2006-11-02 for system for monitoring propane or other consumable liquid in remotely located storage tanks.
Invention is credited to Richard L. Humphrey.
Application Number | 20060243347 11/396048 |
Document ID | / |
Family ID | 37073969 |
Filed Date | 2006-11-02 |
United States Patent
Application |
20060243347 |
Kind Code |
A1 |
Humphrey; Richard L. |
November 2, 2006 |
System for monitoring propane or other consumable liquid in
remotely located storage tanks
Abstract
An improved apparatus and method for monitoring the levels of
propane or other consumable liquid in remotely located storage
tanks and coordinating delivery of liquid to those tanks, including
an improved method of using the remote monitoring data to identify
out-of-ordinary conditions at remote tanks, optimally schedule
purchases or deliveries, improve safety, and more efficiently
operate a propane dealership. More accurate and timely information
concerning the status of customer tanks serves to improve
operational efficiencies and increase safety. Data received from
remote sensors can be collected and organized so that it is easily
understood and utilized through the implementation of a user
interface accessible via the Internet that allows the information
to be presented in an efficient graphical and contextual fashion.
Operational efficiencies can also be improved by calculating
site-specific Degree-days and K-factors for each tank and by taking
historical propane usage for each tank, weather conditions, and
projected fuel usage into account.
Inventors: |
Humphrey; Richard L.;
(Eddyville, KY) |
Correspondence
Address: |
MICHAEL O. SCHEINBERG
P.O. BOX 164140
AUSTIN
TX
78716-4140
US
|
Family ID: |
37073969 |
Appl. No.: |
11/396048 |
Filed: |
March 31, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60668211 |
Apr 2, 2005 |
|
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|
60683465 |
May 20, 2005 |
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Current U.S.
Class: |
141/95 |
Current CPC
Class: |
F17C 2205/0323 20130101;
F17C 2250/072 20130101; F17C 2250/075 20130101; F17C 2250/077
20130101; F17C 2250/0413 20130101; F17C 2221/033 20130101; F17C
2265/04 20130101; F17C 2223/0153 20130101; F17C 2221/035 20130101;
F17C 2250/0491 20130101; F17C 2260/015 20130101; F17C 2250/0417
20130101; F17C 2250/036 20130101; F17C 3/00 20130101; F17C 2221/01
20130101; F17C 2250/032 20130101; F17C 2223/033 20130101; F17C
2250/034 20130101; F17C 2260/038 20130101; F17C 2250/0439 20130101;
F17C 2260/022 20130101 |
Class at
Publication: |
141/095 |
International
Class: |
B65B 1/30 20060101
B65B001/30 |
Claims
1. An apparatus for monitoring fluid levels in a fuel storage tank
comprising: at least one tank sensor providing information
indicative of the amount of fluid in the storage tank; at least one
monitoring unit associated with each storage tank, said monitoring
unit communicatively linked with at least one tank sensor so that
information measured by the tank sensor is communicated to the
monitoring unit and said monitoring unit including a processor to
receive and process the communicated tank sensor information and a
memory to store processed tank sensor information; and wherein at
least one monitoring unit is capable of calculating predicted fluid
levels based upon communicated tank sensor information and
comparing actual fluid levels to predicted fluid levels to
determine whether a predefined out-of-ordinary event has
occurred.
2. The apparatus of claim 1 wherein the at least one monitoring
unit is also communicatively linked with a temperature sensor that
provides temperature information indicative of the ambient
temperature at the storage tank location, and wherein said
monitoring unit processor also receives and processes the
communicated temperature information and said memory stores
processed temperature information.
3. The apparatus of claim 2 wherein processing the communicated
tank sensor information and temperature information comprises:
using stored fluid level information to determine historical fuel
usage for each tank; using said temperature information to
calculate the number of elapsed Degree-Days for each tank location;
using historical fuel usage and Degree-Day values to calculate a
predicted fluid level for each storage tank; and comparing the
predicted fluid level to the actual fluid level determined from
fluid level information received from said fluid sensor to
determine whether a predefined out-of-ordinary event has
occurred.
4. The apparatus of claim 1 further comprising a valve capable of
shutting off the flow of fuel out of the storage tank, said valve
operably connected to said monitoring unit so that the valve can be
closed when a predefined out-of-ordinary event has occurred.
5. The apparatus of claim 2 further comprising at least one central
server remotely located from the storage tank and communicatively
linked with said monitoring unit so that processed fluid level and
temperature information is communicated from said monitoring unit
to the central server.
6. The apparatus of claim 5 wherein said information is
communicated from said monitoring unit to the central server by a
satellite communication system.
7. The apparatus of claim 6 further comprising: one or more
secondary sensors for detecting the occurrence of a local phenomena
and transmitting a detection signal to the monitoring unit; said
monitoring unit being capable of receiving a detection signal from
secondary sensors, processing the signal, and sending data
concerning the detection signal through a communications link to
the central server.
8. The apparatus of claim 7 wherein said detection signal is
transmitted from the one or more secondary sensors to the
monitoring unit by a wireless RF signal.
9. The apparatus of claim 5 further comprising a satellite
communication system for communicating said information from the
monitoring unit to the central server and a wireless RF
transceiver.
10. The apparatus of claim 5 wherein said central server comprises
one or more computers at one or more physical locations executing
software.
11. The apparatus of claim 1 further comprising a graphical user
interface configured to download information to be displayed and to
allow user input.
12. The apparatus of claim 11 wherein the graphical user interface
is an Internet web browser.
13. The apparatus of claim 11 wherein information concerning fluid
level data is organized and displayed graphically.
14. The apparatus of claim 13 wherein displaying information
graphically comprises displaying a tank inventory listing customers
and corresponding fluid levels with levels above or below
predetermined thresholds color-coded so that particular fluid
ranges can be easily identified.
15. The apparatus of claim 13 wherein displaying information
graphically comprises displaying alarm messages whenever a remote
monitoring unit has notified the central server that a predefined
out-of-ordinary event has occurred.
16. The apparatus of claim 15 further comprising sending alarm
messages via pager, text messages, or email whenever a remote
monitoring unit has notified the central server that a predefined
out-of-ordinary event has occurred.
17. The apparatus of claim 1 wherein the tank sensor comprises a
pressure gauge.
18. The apparatus of claim 1 wherein said monitoring unit is housed
within a non-metal housing which isolates the monitoring unit from
the atmosphere surrounding the housing and wherein said monitoring
unit is communicatively linked with at least one tank sensor by way
of an explosion-proof electrical connection.
19. The apparatus of claim 18 wherein the monitoring unit housing
is mounted onto the storage tank.
20. A method of monitoring two or more liquid fuel storage tanks
comprising: determining the fluid level in each storage tank by way
of at least one monitoring unit associated with each storage tank
and communicatively linked with a fluid sensor that provides fluid
level information indicative of the amount of fluid in the storage
tank and with a temperature sensor that provides temperature
information indicative of the ambient temperature at the storage
tank location, said monitoring unit including a processor to
receive and process the received fluid level and temperature
information; storing said fluid level and temperature information
for each storage tank; determining historical fluid levels for each
storage tank over a time period from stored fluid level
information; calculating the number of Degree-Days over said time
period for each tank location using said temperature
information.
21. The method of claim 20 further comprising communicating said
fluid level and temperature information from each monitoring unit
to at least one central server capable of processing and storing
said information, said central server remotely located from the
storage tanks and communicatively linked with said monitoring
units.
22. The method of claim 20 further comprising: using historical
fuel levels and Degree-Day values to calculate predicted fluid
levels for each storage tank; and comparing actual fluid levels
determined from fluid level information received from said fluid
sensors to predicted fluid levels to determine whether a predefined
out-of-ordinary event has occurred.
23. The method of claim 22 wherein said determining whether a
predefined out-of-ordinary event has occurred comprises comparing
current fluid levels to predefined thresholds or stored historic
fluid levels to determine whether fluid levels are too high, too
low, or whether fluid levels are falling too fast or not falling
fast enough.
24. The method of claim 22 wherein said determining whether a
predefined out-of-ordinary event has occurred comprises comparing
current fluid level to predicted fluid levels.
25. The method of claim 22 wherein comparing actual fluid levels
determined from fluid level information received from said fluid
sensors to predicted fluid levels to determine whether a predefined
out-of-ordinary event has occurred further comprises activating a
remotely operated valve to shut down the flow of fuel from at least
one of said storage tanks if a predefined out-of-ordinary event has
occurred.
26. The method of claim 20 further comprising using historical fuel
levels and Degree-Day values to calculate predicted fuel remaining
in at least one of said storage tanks having a fluid level of less
than 5%.
27. The method of claim 20 further comprising using historical fuel
levels and Degree-Day values to calculate predicted fuel remaining
in at least one of said storage tanks having a fluid level of
0%.
28. The method of claim 20 further comprising using historical fuel
levels and Degree-Day values to calculate predicted fuel that will
be remaining in two or more storage tanks at a future time.
29. A system for monitoring propane in two or more remotely located
storage tanks at different locations, comprising: at least one
monitoring unit associated with each storage tank and
communicatively linked with a sensor that provides information
indicative of the amount of fluid in the storage tank and with a
temperature sensor that provides temperature information indicative
of the ambient temperature at the storage tank location, said
monitoring unit including a processor to receive and process the
received fluid level and temperature information, and said
monitoring unit to use stored fluid level information to determine
historical fuel usage for each tank, use said temperature
information to calculate the number of elapsed Degree-Days for each
tank location, use historical fuel usage and Degree-Day values to
calculate a predicted fluid level for each storage tank, and
compare the predicted fluid level to the actual fluid level
determined from fluid level information received from said fluid
sensor to determine whether a predefined out-of-ordinary event has
occurred; at least one central server remotely located from the two
or more storage tanks to be communicatively linked with each
monitoring unit, said central server to process received propane
level information to provide displayable fluid level data, and
forecast future propane levels utilizing at least stored historic
propane level data; a graphical user interface connected to the at
least one central server via the Internet and configured to allow
user input and to download information to be displayed so that (i)
information concerning propane level data is organized and
displayed graphically, (ii) information is at least displayed as a
tank inventory listing customers and corresponding propane levels
with levels above or below predetermined thresholds color-coded so
that particular propane ranges can be easily identified, and (iii)
alarm messages are displayed whenever a remote monitoring unit has
notified the central server that a predefined out-of-ordinary event
has occurred or that a secondary sensor has detected a value is
outside a predetermined range; and a valve capable of shutting off
the flow of fuel out of the storage tank, said valve operably
connected to said monitoring unit so that the valve can be closed
when a predefined out-of-ordinary event has occurred.
30. The system of claim 29 further comprising: one or more
secondary sensors capable of detecting local temperature, the
presence of propane gas, or higher than normal levels of carbon
monoxide and transmitting a detection signal to at least one
monitoring unit; and at least one monitoring unit to receive a
detection signal from a secondary sensor, process the signal to
determine whether the value is outside a predetermined range and,
if so, send data concerning the detection signal through a
communications link to the central server.
Description
[0001] This application claims priority from U.S. Provisional
Application No. 60/668,211 filed on Apr. 2, 2005 and from U.S.
Provisional Application No. 60/683,465 filed on May 20, 2005, both
of which are incorporated by reference.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates to an improved system for
delivering propane or other consumable liquid to and monitoring
liquid levels in remotely located storage tanks.
BACKGROUND AND SUMMARY OF THE INVENTION
[0003] Propane is a gas, a derivative of natural gas and petroleum.
It is one of the many fossil fuels that are included in the
liquefied petroleum (LP) gas family. Because propane is the type of
LP-gas most commonly used in the United States, propane and LP-gas
are often used synonymously.
[0004] Under normal atmospheric pressure and temperature, propane
is a gas. Under moderate pressure and/or lower temperatures,
however, propane changes into a liquid. Because Propane takes up
much less space in its liquid form, it is easily stored as a liquid
in pressurized tanks. When propane vapor (gas) is drawn from a
tank, some of the liquid in the tank instantly vaporizes to replace
the vapor that was removed.
[0005] Homes and businesses use about one-third of the propane
consumed in the U.S. Propane is used mostly in homes in rural areas
that do not have natural gas service. More than 20 million
households use propane to meet some of their energy needs, while 16
million households use propane as their main heating source. Homes
that use propane as a main energy source usually have a large
propane tank outside of the house that stores propane under
pressure as a liquid.
[0006] Because home space heating is a primary use of propane,
demand is much higher during the winter months. Residential users
of propane typically have a 250-500 gallon tank installed by a
local propane dealer and accessible to delivery trucks for
refilling. Depending on the climate, a typical residential tank is
filled three to four times per year. A residential tank is usually
owned by the propane dealer and rented to the residential customer
for an annual fee.
[0007] Propane dealers typically operate out of bulk storage plants
that include one to two 30,000 gallon storage tanks. A single
dealer will usually be able to effectively service a 35 mile radius
around the plant, though in less populated regions a much larger
service area may be necessary to achieve sufficient volume. Propane
is delivered to customers by bulk delivery trucks or "bobtails"
which typically hold from 1,800 to 3,000 gallons of propane.
Customer tanks usually make up the largest portion of a dealer's
assets.
[0008] Obviously, different size tanks and different usage rates
for customers over a large area can make it very challenging for a
dealer to keep all of his customers' tanks filled. The quantity of
liquid propane stored and remaining on customer propane tanks needs
to be measured frequently so that the propane dealer can manage his
own inventory of bulk propane, efficiently schedule deliveries, and
most importantly keep his customers supplied with propane. There
are also significant safety concerns associated with propane tank
levels since empty or overfilled tanks can be very dangerous.
Further, costs associated with delivery, including wages for
delivery personnel and vehicle operation and fuel costs, are a
significant portion of a dealer's operating expenses. For this
reason, dealers must try to maximize the ratio of gallons of
delivered propane per mile traveled by delivery vehicles in order
to lower delivery costs.
[0009] Traditionally, the standard practice was for propane dealers
to periodically visit each tank and visually read a gauge located
on the tank in order to determine whether the tank needed
refilling. If the tank level was low, it would be refilled; if not,
the delivery truck had essentially wasted a trip. As could be
expected, this highly inefficient practice contributed to higher
costs, both for the dealer and the customers.
[0010] For this reason, a number of forecasting methods were
developed to give dealers a better idea of how much propane a
customer was using and when more should be delivered. Since propane
is primarily used as a heating fuel, the typical forecasting method
involved factoring temperature and historic customer usage rates. A
Degree Day is a unit used to measure how cold it has been over a
24-hour period. The base temperature for Degree-day calculations is
65 degrees. The actual temperature is compared to the 65.degree.
base temperature and if the temperature is lower, the difference is
the number of Degree-days for that day. For example, if the average
temperature for a 24-hour period was 60.degree., that would be
5.degree. less than the base temperature of 65.degree., so we would
have 5 Degree-days for that 24-hour period. Another concept,
referred to as the K-factor, is used to get an idea of the propane
usage rate for a customer. The customer's K-factor is the number of
Degree-days that it takes for a given customer (or burner(s)
associated with a given tank) to use one gallon of propane.
[0011] From these two measurements, a dealer could get a better
idea as to when more propane should be delivered. For example, a
customer with a 275-gallon propane tank with a historic K-factor of
5 could be expected to go 1375 Degree-days before the tank is
empty. However, since an empty tank is a dangerous condition (plus
it means the customer is out of fuel) delivery will need to be made
before the 1375 Degree-days have elapsed. Further, these types of
forecasting methods cannot account for unexpected periods of higher
or lower than normal propane usage. Since this kind of forecasting
is merely an estimate, a substantial margin of error must be built
into the delivery schedule. This results in more deliveries of
lower amounts of propane and consequently higher dealer delivery
costs.
[0012] For many years, various optimal vehicle routing computer
programs have been available to minimize the mileage and travel
time associated with making desired deliveries using vehicles with
known capacities. All such methods in the prior art, however,
necessarily depend upon various methods of forecasting a customer's
propane usage since the last delivery and, as discussed above, such
forecasting methods are never completely reliable.
[0013] More recently, remote monitoring systems have been used to
allow remote transmission of data relating to the level of the
liquid gas contained in customer tanks. This allows for the
delivery of fuel or other fluids to the storage tank on an
"as-needed" basis. Such monitoring systems are typically more
accurate than forecasting systems and increase the efficiencies of
the propane supplier.
[0014] Storage tank monitoring systems currently in use typically
include a float sensor within a storage tank that measures the
level of fluid and the temperature within the storage tank. For
remote monitoring systems, data from the sensor is transmitted
through some type of communication network to a data processing
unit or display device. Typically, the data processing unit is a
computer that decodes and stores the data using specialized
software. The information received by the data processing unit
provides for the monitoring of each specific storage tank
individually.
[0015] One remote monitoring system known in the prior art makes
use of RF broadcasting to communicate data from the sensor to the
data processing unit. Such systems are relatively inexpensive,
however, they have very limited range. The data processing unit
would typically be mounted in a delivery truck which would have to
be in the vicinity of the customer's tank for the level to be
reported.
[0016] Another prior art system uses a modem and ordinary telephone
lines to communicate data from the sensor to the data processing
unit. Typically, such a system will use the modem to call in and
signal the data processing unit when the propane in a tank reaches
a pre-determined level. The customer's phone line must be free for
the system to work.
[0017] Other prior art systems used to monitor liquid volume in
tanks make use of satellite or cellular communications. However,
each of these systems also suffers from disadvantages in certain
circumstances. For example, many satellite systems require an
externally mounted satellite dish with the proper exposure.
Additionally, two-way communication requires expensive equipment
and installation. Cellular systems are not practical in certain
locations due to a lack of cellular coverage.
[0018] No matter which communication scheme is used, the data
received from the sensor is often confusing and can require
significant time to decode and format into a useful form. Even
then, it is still difficult for a dealer to interpret the data or
use the information to optimally organize his trucks and routes.
Further, a dealer must be able to access the data processing unit
in order to make use of the data, and this typically requires that
the dealer be physically in his office in order to monitor his
business. Also, certain tank conditions, such as an over-fill or
gas leak, require immediate attention. It is sometime difficult to
identify certain dangerous conditions. For example, data showing
rapidly falling fuel levels could indicate a leak or could simply
result from a period of high fuel usage. For events occurring
outside ordinary business hours, either the dealer must have an
employee monitoring the system 24 hours a day or else these events
will not be corrected until the next business day.
[0019] Propane dealers also face economic challenges arising from
the seasonal nature of propane demand. As discussed above, demand
for propane is high during the winter months, but much lower during
summer. The propane dealer has a significant investment in tanks,
trucks, employees, and infrastructure, and yet he receives a poor
return on this investment during periods of low demand.
[0020] What is needed is an improved system for monitoring the
levels of propane or other consumable liquid in remotely located
storage tanks and to better coordinate delivery of liquid to those
tanks.
SUMMARY OF THE INVENTION
[0021] An object of the invention, therefore, is to provide an
improved apparatus and method for monitoring the levels of propane
or other consumable liquid in remotely located storage tanks and to
better coordinate delivery of liquid to those tanks. This goal is
achieved through a novel combination of remote monitoring of
customer tanks and an improved method of using the remote
monitoring data to identify out-of-ordinary conditions at remote
tanks, optimally schedule purchases or deliveries, improve safety,
and more efficiently operate a propane dealership.
[0022] The foregoing has outlined rather broadly the features and
technical advantages of the present invention in order that the
detailed description of the invention that follows may be better
understood. Additional features and advantages of the invention
will be described hereinafter. It should be appreciated by those
skilled in the art that the conception and specific embodiments
disclosed may be readily utilized as a basis for modifying or
designing other structures for carrying out the same purposes of
the present invention. It should also be realized by those skilled
in the art that such equivalent constructions do not depart from
the spirit and scope of the invention as set forth in the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] For a more complete understanding of the present invention,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawings,
in which:
[0024] FIG. 1 shows a preferred embodiment of a remote propane
monitoring system according to the present invention where a
cellular communication scheme is employed.
[0025] FIG. 2 shows a preferred embodiment of a remote propane
monitoring system according to the present invention where a
satellite communication scheme is employed.
[0026] FIG. 3 shows a typical prior art liquid storage tank and
float gauge.
[0027] FIG. 4 shows a preferred embodiment of a monitoring unit for
use with a cellular communication scheme.
[0028] FIG. 5 shows a preferred embodiment of a monitoring unit for
use with a satellite modem.
[0029] FIG. 6 is a typical delivery schedule screen according to
the present invention.
[0030] FIG. 7 is a typical delivery truck routing screen according
to the present invention.
[0031] FIG. 8 is a daily posted customer tank inventory chart
according to the present invention.
[0032] FIG. 9A is a geographic satellite view of a dealer's
customer tanks and their current levels.
[0033] FIG. 9B is the geographic satellite view of claim 9A zoomed
in to show an individual customer.
[0034] FIG. 10A shows the exterior of an explosion-proof case
according to the present invention.
[0035] FIG. 10B shows the interior of explosion-proof case
according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0036] A preferred embodiment of this invention provides a novel
system and method for monitoring the levels of propane or other
consumable liquid in remotely located storage tanks and an improved
system to coordinating the delivery of a liquid to remotely located
storage tanks.
[0037] Although much of the following description is directed
toward propane storage and delivery, the present invention could be
utilized with any type of consumable liquid commonly stored in
liquid storage tanks, including natural gas or anhydrous ammonia.
Hence, the scope of the present invention should not be limited to
propane storage and delivery. Further, although much of this
discussion is directed an economic model including a propane dealer
servicing propane tanks located at customer sites, the system and
methods discussed herein would be equally applicable to different
economic models, including for example, a large corporation or
other business entity servicing a large number of remote storage
tanks from one or more central storage facilities.
[0038] In accordance with another aspect of a preferred embodiment
of the present invention, an agnostic communication scheme can be
used for remote monitoring of liquid gas levels in storage tanks.
Thus, communication does not have to be limited to a single
communication platform. Any known suitable communication scheme can
be employed to transmit data, such as cellular, land phone lines,
wireless, satellite, cable, etc. Different communication schemes
can be employed for different customers or tank locations,
depending on which scheme is optimal for the individual client or
location. Selection of an optimal communication network can be
based upon factors such as location, availability of cellular
signal, availability of telephone lines, and desired equipment
investment by customer.
[0039] FIG. 1 shows one aspect of a preferred embodiment of a
remote propane monitoring system 100 according to the present
invention where a cellular communication scheme is employed to
transfer data between a storage tank monitoring unit and the
central server. Remote propane monitoring system 100 comprises
central processing station 102 which communicates with a plurality
of monitoring units 107 located at customer sites 106 by way of one
or more cellular towers 104. Communication between central server
102 and monitoring units 107 is preferably two-way communication.
As discussed in greater detail below, monitoring units collect data
from the propane tank sensor and optionally from one or more home
monitoring sensors 108 and transfer fluid level data to the central
server 102. Data can then be organized and processed (as also
discussed below) and transferred from central server 102 through
satellite up-link 128 to satellite 110 and/or through web server
124 to the Internet or a suitable intranet. Central server 102 can
comprise one or more computers at one or more locations. End-user
130 can then access data through a wireless satellite link or
through the Internet, for example by using a personal computer with
Internet access. Central server 102 can also communicate with
delivery trucks 140 by way of cellular towers 104.
[0040] FIG. 2 shows another preferred embodiment of a remote
propane monitoring system 200 according to the present invention
where a satellite communication scheme is employed to transfer data
between a storage tank monitoring unit and the central server.
Remote propane monitoring system 200 comprises central server 102,
which communicates with a plurality of monitoring units 207 located
at customer sites 106 by way of satellite 210. Monitoring units 207
can communicate with satellite 210 by way of a satellite modem and
antenna (not shown). In the embodiment shown in FIG. 2
communication is one-way from the monitoring units 207 to the
satellite 210. Even more preferably, however, communication between
monitoring units 207 and satellite 210 can be two-way
communication. As discussed in greater detail below, monitoring
units collect data from the propane tank sensor and optionally from
one or more home monitoring sensors 108 and transfer fluid level
data to the satellite 210. Data is then transferred to central
server 102 by way of satellite up-link 228. Data can then be
organized and processed (as also discussed below) and transferred
from central server 102 through web server 224 to the Internet or a
suitable intranet. End-user 130 can then access data through the
Internet or suitable intranet, for example by using a personal
computer with Internet access. Optionally, monitoring units on
delivery trucks 140 can also communicate with the central server
102 by way of the satellite 210 and satellite up-link 228.
[0041] Tank levels can be monitored by a number of different
mechanisms known in the prior art. For example, one common type of
gauge is known as a float gauge. As the name suggests, a float
gauge has a float that rests on the surface of the fluid being
measured. The position of the float will rise or fall as the level
of liquid in the tank is changed. Movement of the float is sensed
by a gauge, typically through the use of a magnetic coupling, to
provide an indication, either visual or otherwise, of the fluid
level. A typical float gauge and propane tank combination 300 is
shown in FIG. 3. Float assembly 302 is mounted inside tank 304. As
illustrated in FIG. 3, the position of float 306 will vary with the
liquid levels 308 and 310 in the tank. The float assembly 302
represents the attachment mechanism through which the sensor unit
of the present invention detects the level of the propane inside
the tanks. Vertical movement of the float as it follows the level
of the liquid is converted into rotational movement by a pinion 312
which rotates a shaft extending inside tube 314 and turns a master
magnet 316. The float assembly 302 attaches by the float head 318
under a pressure seal. A dial gauge 320 is mounted onto the float
head 318.
[0042] The dial gauge 320 will preferably comprise a dial chamber
with a remote sender that gives a visual indication of tank levels
while also sending an electrical signal to a monitoring unit. This
electrical signal serves to give a remote indication of the tank
levels.
[0043] FIG. 4 shows a preferred embodiment of a local customer
monitoring unit 400 according to the present invention. Monitoring
unit 401 comprises a sealed case 403 containing processor 402 and
at least one associated communication device 404, such as a
cellular modem, line modem or satellite communication device. For
example, FIG. 5 shows a preferred embodiment where the
communication device is a satellite modem 518 with a flat array
antenna 516. Communication device 404 can be connected to external
antenna 424. Processor 402 and associated communication device 404
are preferably powered by batteries 422 or optional external power
supply 423, and communicate with one or more propane tank sensors
412 through I/O port 405. Status and troubleshooting information
can be displayed externally via LEDs 408.
[0044] Processor 402 comprises circuitry for implementing the
following functions: receiving data from the one or more propane
tank sensors 412; processing the data, and converting it into
readable form if necessary; at preselected intervals or times,
connecting to the central server (not shown) through the associated
communication device 404 and external antenna 424 to transfer
collected data; and determining whether predefined conditions have
occurred, such as a low liquid level or an overfill, or whether
predefined abnormal or "out of ordinary" events have occurred, such
as liquid levels dropping too fast (possibly indicating a leak) or
not dropping at all (indicating a possible problem with the tank
sensor). As discussed in greater detail below, processor 402 can
also include circuitry for receiving and storing data from one or
more temperature sensors and use that data to calculate
site-specific Degree-day values for each tank location. Skilled
persons will recognize that said circuitry can be implemented with
conventional processors and/or controllers, integrated circuits,
discrete devices, or any combination of the same.
[0045] Processor 402 can communicate with tank level sensor 412 by
way of a direct wire connection 418, I/O port 406, and
communication bus 405. Processor 402 can communicate with a
plurality of additional secondary sensors. For example, data can be
collected from one or more home monitoring sensors 421 capable of
detecting Carbon Monoxide, propane gas, or variations in
temperature inside the customer's home. Data from these types of
additional sensors can be transmitted to the central server along
with data on propane tank levels. Communication between monitoring
unit 401 and home monitoring sensors 421 can be through any
appropriate means, including wireless RF, X-10, direct wiring.
Referring also to FIG. 5 and FIG. 10B, in a preferred embodiment, a
RF antenna 512 and antenna can be built into the circuitry of
processor 402. Alternatively, a second I/O port allows for X-10
functionality as discussed below.
[0046] Preferably case 403 will be sealed to protect the sending
unit from adverse environmental conditions. In the event of
mechanical failure, the entire unit can be easily replaced. In a
preferred embodiment, the monitoring unit of FIG. 4 will also
provide I/O functionality (including data ports allowing the
monitoring unit to communicate with X-10 devices or the customer's
personal computer). Although any appropriate communication device
can be used with the present invention, in a preferred embodiment
the unit will have a primary communication device, such as a
cellular modem, and a backup device, such as a land line modem.
[0047] Monitoring unit 401 can be operated by any appropriate power
source, including direct wiring, battery packs, or solar chargers.
Depending on the power source, the communication device can be
configured to operate in different modes. Preferably, for example,
a monitoring unit that is powered by a battery pack would be
configured so that the communication device, such as a satellite
modem, is powered off most of the time in order to conserve power.
Processor 402 would periodically wake up the communication device
to transmit data or receive incoming commands.
[0048] In a preferred embodiment, monitoring unit 401 could collect
data and report to the central server once per day at a particular
time, for example at 3:00 a.m. In the case of cellular
transmission, this would typically allow a dealer to negotiate a
cheaper cellular rate plan since most transmissions will not occur
during peak cellular times. If landline communication is used,
reporting at 3:00 a.m. should limit the potential interference with
the customer's use of the telephone line. Additionally, as
discussed above, monitoring unit could be configured to report
immediately if certain types of conditions occur, including for
example, overfilled tanks, greater than expected usage (which could
indicate a leak), low battery, or any other "out of ordinary"
condition.
[0049] FIG. 5 shows another preferred embodiment of a local
customer monitoring unit according to the present invention.
Monitoring unit 501 comprises a sealed case 403 containing
processor 520 and battery power supply 514. Satellite modem 518 and
flat array antenna 516 are used to communicate with one or more
remote servers (not shown). Suitable satellite communication
equipment is available, for example, from AeroAstro, Inc. of
Ashburn, Va. RF antenna 512 and transceiver (not shown) are used to
communicate via wireless RF transmission with one or more home
monitoring and automation units such as, for example, Carbon
Monoxide or propane detectors located inside a customer's home.
Data from these RF-enabled units can be stored and processed by
monitoring unit 501. For example, data from interior monitors can
be used to determine whether an automatic tank cut-off should be
activated, as discussed in greater detail below. Data from the
RF-enabled units can also be transmitted to a remote central server
via satellite modem 518.
[0050] In accordance with another aspect of a preferred embodiment
of the present invention, data can be queued until it is reported.
This would allow the collection of very detailed data, for example
hourly tank levels, while minimizing connect time. This would also
allow the communication system to be more tolerant of communication
faults since data would be stored until a satisfactory
communication is established. As discussed in greater detail below,
the data collected and transmitted by the monitoring unit can
include not only tank level data, but also data from home
monitoring sensors (i.e., CO detector(s), propane detector(s),
appliances, smoke detector(s), security sensors, etc.) and data
from an on-site Degree-day recorder and history log.
[0051] In accordance with another aspect of a preferred embodiment
of the present invention, data received from the tank sensors can
be collected and organized so that it is easily understood and
utilized by the propane dealer through the implementation of a user
interface which allows the propane dealer to see each customer's
current status in a graphical and contextual way. This improves the
ability of the propane dealer to analyze and react to data quickly
and easily without the necessity of reviewing voluminous data which
is not organized in an optimum order.
[0052] For example, in a preferred embodiment, basic information
and history would be accessible for each customer or each storage
tank. A color-coded tank inventory can be graphically displayed so
that a dealer can see a list of customers and tank levels and at a
glance tell the status of each customer's tank. FIG. 6 is a typical
delivery schedule according to the present invention. This screen
shows the delivery vehicles selected for use and the customers
scheduled for delivery. In a preferred embodiment, a program
running on the central server makes the selection according to
user-defined criteria. An authorized user can override the
program's selections from this screen. A customer tank inventory is
graphically displayed so that fluid levels can be easily seen.
Tanks with sufficient propane levels can be indicated with a
selected screen color, for example with icons or graphical shapes
of a particular color. Tanks, which need refilling, can be shown
through the use of a different screen color. Over-filled tanks can
be shown through the use of a third screen color.
[0053] FIG. 7 is a typical delivery truck routing screen according
to the present invention. Each stop on the scheduled delivery route
is shown in order with the physical address, tank capacity, and
scheduled delivery amount. Estimated time of delivery and distance
between stops can also be shown.
[0054] A daily posted customer tank inventory chart, as illustrated
in FIG. 8, will preferably allow the dealer to recognize customer
use trends and detect any anomalies, such as an unauthorized tank
fill or pump-out. This chart graphically displays the fluid level
in a customer's tank over a defined time period, for example over a
four-month period. This allows the dealer to immediately identify
the refill dates and to see if there is any drastic change in usage
rates.
[0055] In accordance with another aspect of a preferred embodiment
of the present invention, color-coded data can also be displayed on
a map that shows the location and status of each tank. This would
also provide for easy printing of routes and customer locations for
drivers. Data received from customer tanks would automatically be
used to create color-coded liquid level tank information lists
accessible by the propane dealer. Custom color-coded maps showing
customer locations on each delivery route can be accessed via the
Internet and displayed to a PC screen and printed by delivery
personnel. This allows a dealer to have a geographic or "satellite"
view of all of his customer tanks and current levels and to map
delivery routes that most efficiently utilize the dealer's assets
and ensure that customer needs are met. Preferably, maps will be
able to show an entire customer base, as shown in FIG. 9A, or zoom
in on a particular customer or route, as shown in FIG. 9B.
[0056] In accordance with another aspect of a preferred embodiment
of the present invention, tank sensor data can be used to calculate
the most efficient delivery truck routes. It is desirable to
determine how much propane to load onto each truck, and what stops
to deliver in a cost efficient manner. Utilizing relevant
information, such as tank level data received from customers,
information on delivery trucks and sizes, availability of trucks,
and delivery location points, an adaptive algorithm would
preferably match the needs of the customer database with the
available delivery trucks and model the most efficient routes for
each available truck. By increasing efficiency, dealers can make
more economical use of their equipment and employees and can
maximize gallons per mile and gallons per stop ratios. The modeling
could also be predictive by taking historical propane usage for
each tank, weather conditions, and projected fuel usage into
account in determining which tanks should be refilled along a given
delivery route. Historic, Degree Day, and Julian (Elapsed) Day
forecasting can also be taken into account. A preferred embodiment
could also include a scheduling system that would use the optimum
route determination to provide fill tickets (specifying how much
propane is to be loaded onto each truck) to the staff responsible
for filling up each truck in the morning and to provide routing and
delivery instructions for each driver.
[0057] In accordance with another aspect of a preferred embodiment
of the present invention, the system can calendar required
inspections of customer tanks, homes, and appliances, as required
by industry standards, either after an event, such as an out of gas
situation, or after a proscribed period of time as passed. The
volatile nature of propane gas creates the potential for serious
ramifications to occur should a leaking pipe or joint develop.
Dangerous conditions may also exist where appliances or heating
units with open flames are exposed to uncontrolled fuel. Pressure
testing the entire propane system, inspecting the tank, piping,
regulator, gauges, connectors, valves, vents, thermostats, pilots,
burners and appliance controls on a regular schedule or after an
out of ordinary event occurs can significantly reduce the
possibility of loss of life or property damage. The system will
have the capability to alert the propane dealer and drivers to the
need to perform required testing either on a regular timed basis or
after the occurrence of an out of ordinary event.
[0058] In accordance with another aspect of a preferred embodiment
of the present invention, data (in the form of customer
information, tank inventories, or delivery information) can be
combined with accounts receivable information. Customer accounts
receivable balances can be displayed on a PC screen organized by
route, or printed out on the color-coded route sheets discussed
above. This preferably allows the dealer to arrange for payment
before or on delivery or to reconfigure the delivery route where
satisfactory payment arrangements cannot be made with customer.
[0059] One aspect of a preferred embodiment of the present
invention is directed to a Web-based (Internet and Intranet)
client-server application that enables dealers to access
information relating to the monitoring of their propane tanks and
inventories, along with information related to additional income
producing services as discussed below. Data from remote sensors,
along with the graphical and contextual organization of that data
as discussed above, would thus preferably be available to end-users
(for example, the propane dealer) by way of the Internet, or a LAN,
WAN, or the like.
[0060] The end-user could choose to dedicate a computer monitor or
monitors to the continually updated display of such information.
Information may be stored on either the central server, a web
server, or the end-users computer so that historical patterns and
trends can be identified.
[0061] Additionally, dealers are preferably able to monitor, via a
Web browser interface and in real-time, any alarms or
out-of-ordinary events affecting their customers or business. In a
preferred embodiment, alarm notices--such as a tank overfill
notice, tank low level notice, an out-of-ordinary occurrence, or a
variance from historic or Degree Day data and projections--can be
posted on the Dealer log-in page. The dealer can also be notified
of alarms by pager, text messaging, or email.
[0062] In accordance with another aspect of a preferred embodiment
of the present invention, the use of interactive web-based managed
services software, accessible by a number of dealers through
individual passcode protected Web-site links, allows for
across-the-board system upgrades and enhancements without requiring
massive hardware or CD mailings.
[0063] In accordance with another aspect of a preferred embodiment
of the present invention, the system for remote tank monitoring of
propane tanks can be combined with other products using similar
equipment in order to provide the propane dealer with additional
non-seasonal revenue streams. As discussed above, propane business
is seasonal, with highest demand occurring during the winter
months. Although expensive monitoring equipment, which can include
satellite, cellular, and landline communication systems, is used
primarily during periods of high demand, the equipment remains at
the customer's location throughout the year. Similarly, a propane
business will typically require a staff with a great deal of
technical expertise, but that expertise is generally only put to
use during high demand periods. During the off-season, these highly
trained employees will typically be used for numerous non-technical
tasks.
[0064] According to the present invention, a propane dealer can
take advantage of the expertise of his employees and the existing
monitoring equipment infrastructure to provide additional services
to customers. For example, the equipment used for satellite
communication of remote tank levels can also be used to provide a
customer with satellite television or Internet service. The same
employees who install and service satellite monitoring systems will
be able to use their technical expertise to install and service
satellite entertainment services.
[0065] In a preferred embodiment, wireless RF or X-10 functionality
on the monitoring unit allows home monitoring and automation
services and data to be transmitted with the same equipment used
for tank monitoring (even where satellite equipment is not
installed or is not available.) As is well known to those of
ordinary skill in the art, the term X-10 refers to a standardized
protocol accepted as an industry standard for communication between
devices via AC power lines within a single facility. X-10
communicates between transmitters and receivers by sending and
receiving signals over the AC power line wiring. These signals
involve short RF bursts, which represent digital information. This
X-10 functionality can be controlled by way of the customer's PC,
and can easily be accessed through the Internet. As discussed
above, in a preferred embodiment, the monitoring unit will have a
built-in RF transceiver and antenna allowing the processor to
interface with home monitoring sensors or home automation devices,
such as X-10 devices. Other types of communication protocols and
connections could also be used to connect home monitoring sensors
to the monitoring unit, including hard-wired connections. This
allows the propane dealer to also offer, for a relatively small
equipment and training investment, home security and fire
monitoring, home automation, and specialized monitoring which is
desirable for propane customers, such as Carbon Monoxide and
propane gas monitoring inside the home.
[0066] By combining wireless entertainment and RF or X-10
functionality with the tank monitoring system discussed herein,
both monitoring and additional revenue-producing services
preferably benefit from cost savings and increased
efficiencies.
[0067] In accordance with another aspect of a preferred embodiment
of the present invention, where more than one type of tank
monitoring communication scheme could be used, the communication
scheme can be matched to additional services desired by the
customer, thus creating additional efficiencies and cost savings.
For example, where the customer wishes to purchase satellite
television or Internet services, the same satellite equipment could
be used to provide the communication between the monitoring sensors
and the data server.
[0068] In accordance with another aspect of a preferred embodiment
of the present invention, delivery vehicles and storage tanks could
be equipped with GPS transmitters or transmitter-receivers in order
to track delivery fleet movements and to monitor the location of
tanks. In conjunction with the routing system discussed above,
routes for various trucks could be changed in mid-route and the new
routes delivered to the vehicles GPS system. Additionally, the GPS
system could be combined with an automatic vehicle shut-off system
which could be automatically or manually triggered, for example if
the vehicle gets too far off of its assigned route (indicating that
the vehicle has been stolen).
[0069] In accordance with another aspect of a preferred embodiment
of the present invention, a tank monitoring system could be
equipped with an internal Degree-day monitor for each tank
location. Sensors could preferably be used to continuously or
periodically monitor temperature readings or other weather
conditions at each tank site in order to calculate elapsed
Degree-days for each tank location. Site-specific Degree-day
calculations could be used to more accurately predict tank levels
and to more accurately determine whether an out-of-ordinary event
has occurred. These site-specific calculations could either be
performed by the tank monitoring system processor or the data could
be transmitted to a central server for processing. Daily and
accumulated Degree-days (annual) can be stored either by the tank
monitoring unit or by the central server. As discussed above,
Degree-days have historically been used to estimate propane (or
other fuel) usage. However, the Degree-day monitoring is typically
done only one location, such as the propane dealer's office. In
some parts of the country, daily temperature variations across a
dealer's delivery area can be extreme. Monitoring temperature at
each tank location and using that data to calculate site-specific
Degree-days would be a significant improvement over the prior
art.
[0070] Site-specific Degree-day and historic fuel levels can be
used to calculate the K-factor for each tank. Further, Degree-day
and K-factor calculations can be updated every time a tank's fluid
level is measured. This allows the calculations to better account
for periods of unusual temperatures or usage levels, which in turn
allows for improved detection of out-of-ordinary events such as a
stuck tank float gauge, an open bleed valve, an underground line
leak, or any reduction in fuel level not compatible with a
customer's history and current weather patterns.
[0071] Stored and "real time" Degree-day, K-factor, and usage data
for a given tank can also be used to calculate predicted tank
levels, using for example, a predictive algorithm taking into
account some or all of the data collected and stored by the
monitoring unit. The predicted tank levels can be compared to
actual tank levels to better determine whether an out-of-ordinary
event has occurred. For example, a relatively minor difference
between predicted and actual levels might trigger a customer
contact or a service call to check for problems. A major difference
between predicted and expected levels could trigger a more urgent
response, such as immediate notification of the fuel dealer and
customer or an automatic shut-off of fuel flow as discussed below.
Data from secondary sensors, such as temperature sensors located in
a customer's house, along with Degree-day, K-factor, and usage data
for nearby or similarly situated tanks can also be used to
calculate predicted fuel levels or to more accurately detect
out-of-ordinary events. Again, these site-specific calculations
could either be performed by the tank monitoring system processor
or the data could be transmitted to a central server for
processing.
[0072] In accordance with another aspect of a preferred embodiment
of the present invention, the tank monitoring system could be
configured to automatically shut off propane flow from the tank in
the event of a leak. A significant propane leak in or near a
customer's home can have catastrophic consequences. Automatic leak
detection can be difficult, however. Propane gas detectors have
sensors and batteries that wear out and they need to be located
near the leak to be effective. Also, many propane customers do not
used gas detectors because of the expense or difficulty in
installation. Rapidly dropping fuel levels could indicate a leak,
but could also be the result of sudden high propane usage
(sometimes seen, for example, when the weather turns suddenly
colder or when pool heaters or commercial grain dryers are
operated). On-site Degree-day calculation makes it much easier to
determine when a leak is present. In the event that tank levels are
dropping faster than expected based upon on-site Degree-days or if
levels are falling faster than a predefined amount, a
processor-controlled valve could be used to cut off propane flow
out of the tank. Propane flow could also be shut off if any
secondary monitoring sensor, for example one located inside the
customer's home, detects the presence of a significant amount of
propane gas in the air. Preferably, the shut-off valve could also
be activated if the processor receives a command from the central
server, such as a shut-off command from the dealer.
[0073] In accordance with another aspect of a preferred embodiment
of the present invention, site-specific Degree-day data could be
used to more accurately estimate available storage space in
customer's tanks, which in turn can be used by the dealer to more
accurately predict when the dealer will need to replenish his
inventory. It can take several days for propane to travel through
pipelines to reach a dealer. Propane prices also fluctuate
significantly throughout the year so that it is advantageous for
the dealer to buy as much propane as possible during periods where
the price is low. The more accurately propane usage and available
storage capacity can be estimated, the more efficiently the dealer
can determine when to purchase additional fuel and how much fuel
should be purchased. Accurate information concerning customer tank
levels and predicted usage allows the dealer to better make use of
customer storage capacity allowing the dealer to purchase more
propane when price levels are low. In a preferred embodiment, data
concerning predicted weather conditions can also be combined with
the data discussed above to predict fuel levels several days into
the future.
[0074] In accordance with another aspect of a preferred embodiment
of the present invention, Degree-day data and tank level data can
be used to estimate actual fuel levels in tanks that have dropped
below 5%. The fluid level gauge on a typical propane tank only goes
down to 5%. However, even when the fluid level drops to zero, there
is still a volume of propane gas present in the tank and lines that
can often provide several days of fuel for the customer. Also, it
is important to refill a tank before it has been emptied of all
propane gas because an empty tank can pose a significant safety
hazard. Before refilling, an empty tank may have to be purged of
all air to get moisture out of the tank. Further, the tank should
be pressure tested to make sure there are no leaks. Additionally,
all pilot lights fueled by the tank will have to be re-lit.
Typically, a propane delivery driver will not be able to refill an
empty tank alone because of the time and additional expertise
required. Instead, an employee with more specialized training and
equipment will have to accompany the driver (increasing costs for
the dealer). By using Degree-day data and historic tank level data
to extrapolate fuel or vapor levels for nearly empty tanks, a
dealer can better estimate when a tank will be completely empty.
This will allow him to wait as long as possible before refilling,
but also to make sure that the tank is not completely emptied.
[0075] In accordance with another aspect of a preferred embodiment
of the present invention, a pressure gauge can be mounted onto a
tank so that actual pressure data can be monitored by the tank
monitoring unit in the same way that fluid levels are monitored as
discussed above.
[0076] In accordance with another aspect of a preferred embodiment
of the present invention, the tank monitoring unit is housed within
a protective case designed so that electrical connection to the
monitoring unit takes place within an atmospherically sealed
chamber. A typical electrical connection or metal-to-metal contact
creates a risk of a spark--a potentially hazardous event in the
presence of any significant amount of propane gas.
[0077] FIG. 10A and FIG. 10B show a protective case 403 in
accordance with the present invention. Case 403 is preferably
sealed with an airtight seal to protect monitoring unit circuitry
from adverse environmental conditions and to isolate any electrical
connections within the case from the atmosphere surrounding the
case to prevent explosion in the event of a propane leak. Referring
also to FIG. 5, wire connection 418 is used to carry signals from
dial gauge 320 to monitoring unit 501. Wire connection 418 is
preferably connected to monitoring unit 501 by way of an
explosion-proof electrical connection. When male connector 502 is
connected to female PCB-mount connector 504 a diaphragm or gasket
(not shown) is used to create an airtight seal between the male and
female connectors before any electrical connection is made so that
any spark produced in completing the connection is isolated from
the atmosphere surrounding case 403. Skilled persons will recognize
that an air-tight seal around the wire connection could be
accomplished in a number of ways well-known in the prior art,
including a flexible diaphragm, a gasket, a mechanical valve, or
any combination thereof.
[0078] Because the electrical connections and circuitry within case
403 are isolated from the atmosphere, the case can be mounted
directly onto a tank containing propane or other flammable fuel.
Prior art systems typically make use of a unit mounted inside the
customers home that communicates via wired or wireless
communication with only a sending unit at the tank. By using a
self-contained tank monitoring unit that both receives the data
from the tank, and transmits data to the central server, the system
is much easier to install, allowing drivers rather than service
personnel to handle installation or replacement of defective units.
Also, allowing the entire unit to be safely mounted on the tank
itself provides significant advantages. Access to the customer's
home is not required so that the customer need not be home when the
monitoring system is installed. Further, locating the monitoring
unit outside on the tank makes it easier for the dealer to retrieve
the equipment in the event that a customer does not pay his bills.
In the event of mechanical failure, the entire unit can be easily
replaced, again without requiring access to the customer's home.
Preferably the box is mounted on the tank using a connection method
that does not involve metal-to-metal contact such as highly
adhesive tape affixed to the underside of the unit.
[0079] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made to the embodiments
described herein without departing from the spirit and scope of the
invention as defined by the appended claims. Moreover, the scope of
the present application is not intended to be limited to the
particular embodiments of the process, machine, manufacture,
composition of matter, means, methods and steps described in the
specification. As one of ordinary skill in the art will readily
appreciate from the disclosure of the present invention, processes,
machines, manufacture, compositions of matter, means, methods, or
steps, presently existing or later to be developed that perform
substantially the same function or achieve substantially the same
result as the corresponding embodiments described herein may be
utilized according to the present invention. Accordingly, the
appended claims are intended to include within their scope such
processes, machines, manufacture, compositions of matter, means,
methods, or steps.
* * * * *