Remotely controllable LNG field station management system and method

Abstract

A remotely controllable apparatus, system and method for monitoring, inventory, controlling and reporting on the filling, refilling and dispensing of Liquified Natural Gas (LNG) at portable temporary or semi-permanent field-located storage and dispensing stations, including a portable storage tank, and an associated portable pump and control skid, which skid includes: an on-site microprocessor control system having: security features; pump, fill and dispense connections; an LNG leak detection system; a communications link (typically an RF cellular phone system) to a host computer; a dispensing and refilling sales authorization and initiation system (typically a card reader of the credit, access or proximity card types); and a remotely located host computer having a full suite of features including: inventory, monitoring, security and access control; operational control; financial and transaction record keeping and report generation; and emergency warning and shut-down. The field control unit control functions are performed by the on-site microprocessor which receives input from a plurality of natural gas leak detection sensors, and provides complete on site security screening, data acquisition, transaction recording and control capability, including warning via lights, horn or recorded or synthesized voice, and shut-off or shut-down. The field control unit monitors and controls prescribed user vehicle and storage tank filling procedures, and provides communications to a remote central monitoring site having a host computer master controller, via cellular phone.

Claims

We claim:

1. A cryogenic LNG fuel field station control system for automated control of a typically above-ground LNG fuel storage and dispensing station, which LNG storage and dispensing station includes a portable pump and piping skid assembly for conditioning lines, pumps and valves for cryogenic LNG fuel storage and delivery, and through which both supply tanker and customer user vehicles can be connected to a cryogenic LNG fuel storage tank via a valve manifold for selective refilling of said cryogenic LNG storage tank and for refueling of said user vehicles from said cryogenic LNG storage tank; said cryogenic LNG field station control system comprising:

(a) at least one LNG leak detection sensor sensitive to hydrocarbon fuel vapors mounted in association with said LNG storage and dispensing station;

(b) a means for authorization of customer vehicle fueling and supply tanker refueling use of said LNG storage and dispensing station;

(c) means for communicating with a remote host computer, the remote host computer having means for remote control of said LNG storage and dispensing station; and

(d) a micro controller mounted in association with said station including means for:

i) recognizing authorized users and activating fueling or refueling use of said station upon said recognition;

ii) monitoring system conditioning;

iii) initiating shutting down of said station in response to detection by said sensor of an LNG fuel leak; and

iv) commencing emergency actions upon the occurrence of predetermined emergency conditions, said emergency actions including initiating shut-downs, and transferring records selected from transactions and inventory status to said host computer.

2. Method of operation of a field cryogenic LNG fuel storage and dispensing station comprising the steps of:

(a) maintaining said station in a waiting state monitorable via remote communications link;

(b) reading user identification information on site and comparing said information to an authorized user list which includes at least one authorized fueling customer and at least one resupply vendor;

(c) initializing fueling or refueling operation of said station upon verification of authorization of said user and in accord with the type of user;

(d) monitoring said station operations for pump, valve and LNG leaks;

(e) recording user transactions including vehicle fill quantities and user identification;

(f) communicating selected information regarding said station selected from one or more of station condition, operation, monitoring, user transactions, leak detection and inventory to a remote host; and

(g) shutting down said station in the event of predetermined emergency conditions including LNG leaks in excess of a preset limit.

3. An automated LNG field station control system as in claim 1, wherein:

(a) said authorization means is associated with the LNG storage and dispensing station such that liquid natural gas is dispensed from the storage and dispensing station only when a customer authorization means permits; and which system includes:

(b) a fuel shut off means for shutting off the flow of liquid natural gas from the storage and dispensing station.

4. An automated LNG field station control system as in claim 3, wherein:

(a) the fuel shut off means is controlled by the authorization means to shut off the flow of LNG from the storage and dispensing station except when the authorization means is turned on.

5. An automated LNG field station control system as in claim 3, wherein:

(a) said authorization means is a card reader;

(b) said microcontroller includes control of fuel shut off according to input from the authorization means; and

(c) said fuel shut off means is also controlled by the leak detection sensor such that when a fuel leak is detected by the leak detection sensor then the fuel shut off means shuts down pumping LNG from the storage and dispensing station.

6. An automated LNG field station control system as in claim 3, wherein:

(a) said microcontroller alerts said host computer to said emergency condition.

7. An automated LNG field station control system as in claim 3, wherein:

(a) said microcontroller permits monitoring of one or more of the field station conditions, the tank fuel inventory status, leak detection and user transactions.

8. An automated LNG field station control system as is claim 1 which includes:

(a) a plurality of on-site attendant-less field stations; and

(b) a host computer including means for monitoring one or more of the field station conditions, the tank fuel inventory status, leak detection and user transactions.

9. An automated LNG field station control system as in claim 1 wherein:

(a) said microcontroller permits attendant-less customer fueling from, and supplier refueling of, said station LNG storage tank.

10. An automated LNG field station control system as in claim 1 wherein:

(a) said microcontroller authorized user recognizing means includes means for recognizing fueling suppliers to permit refueling said LNG storage tank.

11. An automated LNG field station control system as in claim 9 wherein:

(a) said microcontroller fueling supplier means includes means for recognizing a fuel supplier vendor and permitting access to a storage tank fill means associated with said valve manifold.

12. An automated LNG field station control system as in claim 10 wherein:

(a) said microcontroller alerts said host computer to said emergency condition.

13. An automated LNG field station control system as in claim 12 wherein:

(a) said microcontroller permits monitoring of one or more of the field station conditions, the tank fuel inventory status, leak detection and user transactions.

14. A method of operation of a field LNG station as in claim 2 which includes the step of:

(a) selecting said users from fueling customers and fuel resupply vendors in accord with said verified user authorization.

15. A method of operation of a field LNG station as in claim 2 which includes the step of:

(a) monitoring said station by a remote host computer, and said monitoring is of one or more of the field station conditions, tank fuel status, leak detection and user transactions.

16. A method of operation of a field LNG station as in claim 15 wherein:

(a) said host computer monitoring step includes iteration to monitor a plurality of said field LNG stations.

17. A method of operation of a cryogenic field LNG fuel storage and dispensing station, the method comprising the steps of:

(a) reading user identification information at the storage and dispensing station;

(b) comparing the user identification information to an authorized user list;

(c) initializing appropriate user operation of the storage and dispensing station when the user identification information matches a listing in the authorized user list;

(d) monitoring the storage and dispensing station for the occurrence of emergency conditions, including hydrocarbon fuel vapor leak detection;

(e) shutting down operation of the storage and dispensing station upon the detection of an occurrence of at least one preselected emergency condition; and

(f) steps (a) through (e) are attendantless operations performed under the control of a microprocessor.

18. The method of claim 17, wherein:

(a) the emergency conditions include detection of an LNG leak in excess of a preset limit.

19. The method of claim 17, which includes the added step of:

(a) detecting an LNG hydrocarbon fuel leak by a leak detector and transmitting an indication of the LNG fuel leak from said detector to the microprocessor.

20. The method of claim 17, which includes the step of:

(a) causing the microprocessor to communicate with a host computer, the host computer being located distant from the field liquid natural gas storage and dispensing station.

21. The method of claim 20, wherein:

(a) transferring records to the host computer when the microprocessor shuts down operation of the storage and dispensing station.

22. The method of claim 21, wherein:

(a) the records include transaction records.

23. The method of claim 20 which includes the steps of:

(a) monitoring said field station by said remote host computer, said monitoring being selected from one or more of field station condition, tank fuel status, leak detection, and user transactions.

24. The method of claim 23 wherein:

(a) said host computer monitoring includes a plurality of field LNG fuel stations.

Description

FIELD

This application relates to an LNG field station management system, and more particularly to a remotely controllable apparatus, system and method for monitoring, inventory, controlling and reporting on the filling, refilling and dispensing of Liquified Natural Gas (LNG) at portable temporary or semi-permanent field-located storage and dispensing stations, including a portable storage tank, and an associated portable pump and control skid, which skid includes: an on-site microprocessor control system having security features; pump, fill and dispense connections; an LNG leak detection system; a communications link (typically an RF cellular phone system); a dispensing and refilling sales authorization and initiation system (typically a card reader of the credit, access or proximity card types); and a remotely located host computer having a full suite of features, including inventory, monitoring, security and access control, operational control, financial and transaction record keeping and report generation, and emergency warning and shut-down.

BACKGROUND

As emphasis shifts to greater use of LNG as an environmentally "green" fuel, the need for free-standing dispensing stations grows. Currently LNG is primarily used for industrial applications, or long term storage of natural gas in liquified form as a space conservation measure. While popular, LNG or propane tank fueling for home, cabin or camp use is still, volumetrically, less than half of all usage.

A major foreseeable growth area is in vehicular use, particularly in mass transit and fleet truck and/or utility van usage. Personal automotive use is still some way off, but promises to become significant as auto emissions reduction target dates approach.

Portable LNG "stations" consisting of a storage tank module (including a valve box) and an associated pumping module or skid have recently become available. These are used at various new field sites, either temporarily until a permanent station with underground tank storage is built, or until the particular job at that site is completed. Examples include industrial or utility vehicle field stations at remote job sites, at airports or where demand requires, e.g. at an industrial plant or vehicle depot when a vehicle fleet or plant operation is converted to LNG fuel.

However, such stations today are manually operated by authorized "station" operator or driver personnel, and have, at best, rudimentary leak detection systems. They are limited in usage in that the filling of the storage tanks is not remotely monitorable at a central station, nor is the dispensing monitorable or subject to charge pre-authorization, monitoring or control. The safety status is not remotely monitorable or controllable for shut-down during emergency or unauthorized usage.

One very serious problem with attendant-less refueling stations is security. The product is expensive and valuable, such that there is a need for accurate tracking of both filing (independent of the supplier's truck in order to verify filling quantities and charges), and user pumping (for full billing to the customer). Thus security is needed for authorized access to both fill and pump to prevent cheating upon filling and theft upon customer use. In addition, the product is a fuel with attendant fire and explosion hazards such that unauthorized use could lead to safety hazards, e.g. deliberate or accidental discharge by unauthorized persons.

A number of U.S. patents have been directed to a variety of detection systems for gas or fluid flow, including: Massa U.S. Pat. No. 4,066,095; Slocum et al., U.S. Pat. No. 4,736,193; Andrejasich et al., U.S. Pat. No. 4,835,522; Furuyama U.S. Pat. No. 4,752,698; and Slocum U.S. Pat. No. 4,740,777. None of these address the special problems of portable field LNG storage/dispensing stations.

Accordingly, in order to facilitate the use and expand access to meet customer usage requirements, there is a need for specially adapted systems to remotely monitor and control operations at attendantless free-standing LNG field stations, and to permit user card-controlled access payment and dispensing 24 hrs/day while maintaining a high degree of security and the ability to remotely change security access codes in real time as safety and customer needs require.

Such a system needs to be: remotely controllable via a wireless communications link; have the ability to monitor day to day usage; inventory the remaining supply and signal refilling as demand varies; authorize, restrict and control access; provide field condition instruction and use instructions; sense dangerous operations including leak detection; keep a history of transactions and inventory; and signal and control operations, including shut-downs or shut-offs during emergency conditions.

THE INVENTION

OBJECTS

It is among the objects of the invention to provide a remotely addressable operating and control system for a portable free-standing LNG field storage and dispensing station;

It is another object to provide a control system for a portable LNG field station which features operations monitoring and control systems that are linked to one or more remote host computer(s) or microprocessor(s), preferably via RF cellular phone; or land lines;

It is another object to provide a portable LNG field station that includes an LNG leak detection system employing an array of sensors and a control'system responsive thereto;

It is another object to provide an LNG station control system which includes station inventory and condition monitors and a user card reader which permits operational access and authorization for fill or dispensing, and also records transactions for payment and/or inventory purposes, and which control system can be remotely accessed, monitored and directed via wireless communications link;

It is another object of the invention to provide computer programs for field microprocessor control of the LNG refueling station and for communications link to a remote host computer, and computer programs for host computer remote monitoring and control of the LNG station;

It is another object to provide security access and operational features for control of an LNG fueling station, be it a portable remote field station or a more permanent site, and which permits remote monitoring and rapid change of security codes for access and use of the station; and

Still other objects will be evident from the Specification, Claims and Drawings of this Application.

DRAWINGS

The invention is illustrated in connection with the drawings in which:

FIG. 1 is a schematic elevation view of one embodiment of the control system enclosures and layout of this invention as mounted on the LNG skid, with some of the component features identified;

FIG. 2 is an elevation view of the display in the skid control box including the LCD user prompt panel and a schematic layout of the storage tank, valve box and control skid which is operated by the control system of this invention;

FIG. 3 is a schematic diagram of the flammable sensor transmission circuit, including a heater power circuit FIG. 3a and a sensor signal conditioning circuit FIG. 3b;

FIG. 4 is a block diagram of the interface board between the flammable gas sensor transmission circuit of FIG. 3 and the skid microcontroller circuit of FIG. 6;

FIG. 5 is a two-part block diagram of the digital I/O board which is the primary interface for all other (non-gas) sensor inputs/outputs and the microcontroller circuit of FIG. 6 and wherein FIG. 5a shows the input circuitry and FIG. 5b is the output circuitry;

FIG. 6 is a block diagram of the microcontroller circuit.

FIG. 7 is a logic block diagram of the control modes of the field microprocessor control system;

FIG. 8 is a logic diagram of the operator modes programmed into the field microcontroller firmware for microprocessor control of the operations;

FIG. 9 is a flow sheet of vehicle fill operations as controlled by the microcontroller firmware;

FIG. 10 is a flow sheet of the TVAC fill operation as controlled by the microcontroller firmware;

FIG. 11 is a flow sheet of the microcontroller modem control operations;

FIG. 12 is a flow diagram of the top level control of the host computer;

FIG. 13 is a flow sheet of the several control mode operations of the host computer;

FIG. 14 is a flow sheet of the host computer system software routine for initializing the system control flow;

FIG. 15 is a flow sheet of the host computer system tasks control software;

FIG. 16 is a flow sheet of the host computer change of part status check and control operation; and

FIG. 17 is a flow sheet of the host computer control of task reevaluation.

SUMMARY

The invention comprises a remotely and locally accessible control system, apparatus and method, for control of a refueling station, and more particularly to a free-standing portable LNG field fueling station. The control system includes a remote host computer having a wide range of access, operations and safety control, system status and monitoring, inventory, report generating, input, display and security features, which can poll the field station's controller via wireless or land line communications to effect monitoring and control of all phases of operation of a portable field LNG refueling station. The system of the invention also includes a remote field microprocessor-based control unit in association with the storage tank and pump/valve assembly for control of the operations of the station itself, and which field controller is linked to the remote host computer.

The field control unit includes the microprocessor control unit featuring firmware resident in microcontroller OT ROM (which is One-Time programmable ROM), or equivalent programmable device, plus system parameter data stored on 512 Kbyte 8 bit EEPROM, (Electrically Erasable PROM), with output function leads, an access and user card reader, a communications link such as an RF cellular phone, and an array of leak detection sensors. The field control unit is housed in an explosion-proof housing, typically a 1" thick aluminum box having a safety glass port for viewing condition monitoring and user instructions display(s) therein.

The field control unit is typically mounted on or associated with a skid-mounted pump and switchable valving system (valve manifold) for handling of the liquid fuel into and out of a storage tank mounted on a separate skid, typically a 5000 gallon LNG tank skid (a TVAC) having an appropriate valve box with supply, vent and recirculation input/output piping and valves.

In operation, the field control unit can be locally or remotely accessed and polled for status, control, and security code modification. The field control system provides electronic control, communications, transaction recording, security access control and leak detection. The field control unit of the invention is housed in one or more NEMA 7 class explosion-proof enclosures, typically one for the user card reader and keypad, and one for the remaining components, which include: The station controller, herein called the microprocessor or micro controller to distinguish it from the remote host computer; the liquid crystal display (LCD) for displaying user operating prompts and station condition messages; a viewport accessing a schematic of the storage tank and pump skid showing line, valving and leak detection (LD) layouts, and having red/green LED lights indicating status of the pump, valves and LD sensors; the cellular phone transceiver; and manual override controls.

The field control unit control functions are performed by the on-site microprocessor which receives input from a plurality of natural gas leak detection sensors, in the example shown, six such sensors, and provides complete security screening, data acquisition, transaction recording and control capability, including warning via lights, horn or recorded or synthesized voice, and shut-off or shut-down. The field control unit monitors and controls prescribed user vehicle and storage tank filling procedures, and provides communications to a remote central monitoring site having a host computer master controller, via cellular phone. In the event a leak is detected, the field control system microprocessor will secure the field station into a shutdown condition by closing, and/or opening appropriate valves to stop or cause recirculation flow of LNG, stop the pump, activate warning devices (light, horn, annunciators) dial the control monitoring site host and report the shut-down.

Similarly, unauthorized usage attempts, low storage supply, or other incidents can be programmed into the field micro controller to signal the remote host for appropriate action. The field control unit microprocessor can be operated in real time from the remote host by the system operating software portion of this invention, enabling the station to be reactivated within minutes after safe conditions have been restored after shutdown. Likewise security codes can be changed from the host, permitting access by authorized users after an unauthorized access attempt or unauthorized use has triggered shut-off. Note shut-down refers to unsafe (leak detected) conditions, while shut-off refers, generally, to unauthorized access, use or misuse being detected. The microprocessor can be accessed and controlled locally by a laptop computer running the system software. The on-site display of the status of the pump, valves and LD sensors is provided by an array of red/green LEDs in a viewable schematic of the field station tank and pump/controller skid.

Operation of the field system controller system microprocessor for a vehicle fill or TVAC (storage tank) fill operation is initiated by a user inserting a magnetic or proximity card into the card reader slot. The micro controller prompts the user via an LCD display to perform required procedures, and aborts the fill if the user fails to comply after three chances or 90 seconds with no or improper response. The micro controller recognizes at least two types of "cards", a "USER" card and an "OPERATOR" card. The "USER" card is intended for individuals who will be refueling vehicles at the station. The "OPERATOR" card is for station attendants and TVAC storage tank refill suppliers, e.g., tanker drivers. The "USER" card starts the control logic only for a normal vehicle fill operation. An "OPERATOR" card provides a choice of vehicle fill or TVAC fill procedures. The "USER" and "OPERATOR" cards have unique ID numbers which are matched to user name, authorized account, user limits, vehicle ID, and the like. All vehicle fill and TVAC refill operations and transactions are recorded by the micro controller, time and date stamped, and down loaded to the central monitoring station either automatically (preprogrammed) or upon host callup commands.

The system includes a set of manual override controls which are activated by a key switch and/or other authorized access, e.g. by use of the keypad to enter a security code. Activating the manual override inhibits the controller from operating valves or the pump and permits an operator to manually operate the skid. When the manual override controls are in use, the controller will continue to log data, operate the LCD display and/or LED indicators, and communicate with the remote host, and optionally may be capable of station shut-down.

The system operating software sited in the host computer permits remote field service applications. The software is configured for real-time data display and control of the field stations. The software displays plant (layout) diagrams of stations, the transaction history, and provides complete data communications, data acquisition and access/use security control. Communications security for the system is ensured through a call back protocol whereby if a call is received by the field station, it will hang up and call the central monitoring station. The micro controller can be programmed to attempt on the order of 10 or more different phone numbers in case of busy signal, or to continue to dial a prescribed sequence of phone numbers. The host system operating (HSO) software is configured to match the number of field control systems at the time of installation. The HSO software handles an unlimited number of field stations.

DETAILED DESCRIPTION OF THE BEST MODE

The following detailed description illustrates the invention by way of example, not by way of limitation of the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what we presently believe is the best mode of carrying out the invention.

SKID CONTROL SYSTEM APPARATUS

FIG. 1 is an elevation view, primarily schematic, of the enclosures of the control system 1 mounted on a skid herein called the LNG control system skid (item 2 in FIG. 2) or LNG skid for short. The components of the control system include a NEMA-7, controller housing 3, (hinged door not shown), which although shown in an inverted, generally T shape, is preferably a single rectangular enclosure, the upper portion of which includes a viewable backlit graphic display and schematic 4 (shown and described in detail below with reference to FIG. 2) which is visible through explosion proof glass port 5. The card reader unit 6 comprises a slide type, two track mag stripe scanner head 8, a keypad 9, an override key switch 10, an RS232 port 11 for on site computer hook up, in a suitable weatherproof NEMA-4 box (with liftable weather cover), and the electrical leads are connected to the micro controller 12 in the lower portion of enclosure 3 through conduit 13. While the card reader 8 is presently preferred to be a mag stripe "swipe" type scanner, it can be an RF transceiver or other type of proximity card reader.

In the lower portion of the main box 3 is an array of manual override controls 7, from left to right a key switch and pushbuttons DV1, 2, 4 and pump, for manual operation of valves DV1-2 and 4 and the LNG fluid pump, described in more detail below (see schematic in FIG. 2). The manual override array can be separately housed outside the housing 3 and the leads therefore passed through and protected by a suitable conduit. Also attached via conduit 13 to the controller box is a pump starter 14 in a NEMA-7 box 15. The skid power is typically 3-phase 230 VAC as shown by the designated arrow, and the pump power out lines are contained in conduit 16.

The input leads from the sensors (not shown) and the valve switching/control output leads are protected and contained in one or more conduit(s) 17.

The micro-controller assembly 12 includes a power supply, transformer, microprocessor, relays, instrumentation terminal strip(s), a phone modem, panic/reset button, and a cellular phone transceiver which is connected internally to external RF antenna 18. Likewise a NEMA enclosure red warning light 19 is secured to the box 3, or alternately is mounted on a suitable conduit extension in a location and height to be easily visible from all positions around the station.

The controller board 12 preferably includes an Intel KC-196 micro-controller chip 108, e.g., a 16 MHz, 16 bit processor chip with on board A/D (104), 256K SRAM connected (via separate I/F board 102) to a plurality of leak detection sensors, in this embodiment six methane detectors (0-150% Lower Flammability Limit with 30 second reset/recovery time), and a local RS232 interface port for the modem 247 and antenna 18 hookup. The bus 210, power filtering 232, referenced voltage generator 234, A/D 104, oscillator 230, buffers 241, memory 243 and page select 242 are described below in detail with reference to FIG. 6. The I/F board 102, DI0 board 240, and modem are separate. The interconnect wiring is omitted for clarity. The display includes an LCD display 20 for user prompts and a schematic 21 of the tank, valve cabinet, skid, and a valving, pump and sensor layout with red/green LEDs for condition display (see FIG. 2).

FIG. 2 is an enlarged view of the display and schematic 4 visible through port 5, and includes the backlit graphic LCD display 20 and the station schematic 21 as seen by the supply driver, attendant or customer user when filling a vehicle. The schematic 21 shows the outline of 9 transportable tank container 22, preferably a 5000 gallon TVAC.TM. brand tank (Cryenco, Denver, Colo.) container employing high thermal performance vacuum installation system to control heat loss or gain to as low as 0.25.degree. F. per day. Such a tank is typically a steel tank about 20' long, by 8' wide by 9' high, and operates at about 3 bar plus 1 atmosphere vacuum. It includes a manlid, a 11/2" ball type airline valve, a 3" clean flow foot valve with remote controlled butterfly valve, and a 3" threaded or camlock outlet coupling with cap. The tank is generally retained in an internally buttressed steel framework with lift eyes or grapple recesses for transportability. A valve cabinet 23 houses the fittings for connection to the controller skid 2 for fill, refill and customer pumping. The pump 24 is contained on the skid 2. The TVAC tank 22 is filled or refilled via manual valve 25 (labeled DV-7 in the schematic 2) and coupling 26, while the customer user couples the vehicle to be refueled to fuel supply coupling 27 and the vapor return line to fuel vent coupling 28. The array of methane sensors are denominated L1-L6 (Leak sensors 1-6) in schematic 21, and are positioned generally as shown, L1-4 on the LNG skid 2, L5 in the TVAC valve cabinet 23 and L6 adjacent the manual vent manifold valving 29. L1 is capable of sensing leaks in the user vehicle refueling connections, L2 is located adjacent to the bottom fill/draw line 30, L3 between the recirculation line 31 and the vapor return line 32.

The leads from the sensors L1-L6 go to the microprocessor in control system 1 as described above but are omitted for clarity. The signal transmission circuit is contained within an explosion proof NEMA type junction box 38 onto which the Det-Tronics sensor element 36 is mounted. The leads are protected by conduit 37, as shown. Likewise the leads from the relays in the micro-controller go to the solenoid valves DV-1, 2 and 4 on the skid. The condition of each valve, green=open and red=closed, is displayed by the LEDs adjacent the valves. Similarly the LED below the pump, labeled DP-1, shows the pump status, green=on and red=off. A flow meter 33 measures the pumped LNG flow in line 34. DPT-1 is a pressure transducer on the pump output discharge, the signal from which goes to the microcontroller. Likewise, DT-1 measures the pump discharge temperature in line 34. The pressure of TVAC tank 22 is monitored by internal tank pressure transducer PIT-1, and the level of LNG in the tank is monitored by the sensor LG-1. The transducer signals to the microcontroller and the selected relay signals from the microcontroller pass through and are conditioned by the DIO board (FIG. 5 below). A back flow prevention check valve 35 is provided in line 32.

Table I below shows the sensors, channels assigned in the microcontroller 12, the function and the range and signal, as follows:

                                      TABLE I
    __________________________________________________________________________
    Parameters Monitored and Controlled
    Part      Sensor
    ID   Channel
              Type     Location
                            Function  Range   Signal
    __________________________________________________________________________
    L-1   1   Leak     2    Fuel Line 0-150% LFL
                                              0-5 VDC
              Detection     Connections
    L-2   2   Leak     2    HC-1 Connections
                                      0-150% LFL
                                              0-5 VDC
              Detection
    L-3   3   Leak     2    HC-2 and HC-3
                                      0-150% LFL
                                              0-5 VDC
              Detection     Connections
    L-4   4   Leak     2    Pump and DV-7
                                      0-150% LFL
                                              0-5 VDC
              Detection
    L-5   5   Leak     23   TVAC Valve Box
                                      0-150% LFL
                                              0-5 VDC
              Detection
    L-6   6   Leak     22   TVAC Vent 0-150% LFL
                                              0-5 VDC
              Detection
    DPT-1
          7   Pressure 2    Pump Discharge
                                      0-250 psi
                                              0-5 VDC
    DPT-2
          8   Pressure 2    Nitrogen Supply
                                      0-3000 psi
                                              0-5 VDC
                            Pressure
    PIT-1
          9   Pressure 22   Tank Pressure
                                      0-150% psi
                                              0-5 VDC
    DT-1 10   Temperature
                       2    Pump Discharge
                                      100 to -257.degree. F.
                                              mv
                            Temperature
    DFM-1
         11   Flowmeter
                       2    Fuel Flowmeter
                                      0-100 GPM
                                              4-20 ma
    LLT-1
         12   Liquid Level
                       22   TVAC Tank Level
                                      0-100 in H20
                                              0-5 VDC
    DV-1A
         13   Valve Limit
                       2    Suction Valve
                                      open/closed
                                              0-5 VDC
              Switch Open   Open
    DV-1B
         14   Valve Limit
                       2    Suction Valve
                                      open/closed
                                              0-5 VDC
              Switch Closed Closed
    DV-2A
         15   Valve Limit
                       2    Discharge Control
                                      open/closed
                                              0-5 VDC
              Switch Open   Valve Open
    DV-2B
         16   Valve Limit
                       2    Discharge Control
                                      open/closed
                                              0-5 VDC
              Switch Closed Valve Closed
    DV-4A
         17   Valve Limit
                       2    Vent Valve Open
                                      open/closed
                                              0-5 VDC
              Switch Open
    DV-4B
         18   Valve Limit
                       2    Vent Valve Closed
                                      open/closed
                                              0-5 VDC
              Switch Closed
    DPC-1
         19   Pump Current
                       15   Pump Backpressure
                                      0-50 amp
                                              0-5 amp
                            Build-up
    CP-1 20   Pump On/Off
                       15   Pump Operation
                                      Output  110 VAC
              Command
    CR-1 21   Card Reader
                       6    Transaction
                                      Input   Digital
    CV-1 22   DV-1 Command
                       12   Open/Close Valve
                                      Output  110 VAC
                            DV-1
    CV-2 23   DV-2 Command
                       12   Open/Close Valve
                                      Output  110 VAC
                            DV-2
    CV-4 24   DV-4 Command
                       12   Open/Close Valve
                                      Output  110 VAC
                            DV-4
    PB-1 25   Panic Button
                       15   Emergency Shut
                                      Input   110 VAC
              Shut-Off      Down
    CAL-1
         26   Station  12   Activate Red
                                      Output  110 VAC
              Status Lights Warnings Lights
    OB-1 27   Operator Push
                       12   Numeric Key Pad
                                      Inputs  Digital
              Buttons
    LCD-1
         28   CD Display
                       12   Operator  Output  Digital
              Panel         Instructions
    __________________________________________________________________________
     * Location 22 = TVAC; 23  Valve Box; 2 = LNG Skid 15 = LNG Skid Power Box
     6 = LNG Skidcard; = LNG Controller

                  TABLE II
    ______________________________________
    % by Volume in Air for 100% LFL
    ______________________________________
    H.sub.2 (Hydrogen)
                     4.0%
    CH.sub.4 (Methane)
                     5.0%
    C.sub.2 H.sub.6 (Ethane)
                     3.0%
    C.sub.2 H.sub.4 (Ethylene)
                     2.7%
    C.sub.3 H.sub.8 (Propane)
                     2.2%
    C.sub.5 H.sub.12 (Pentane)
                     1.5%
    ______________________________________

                                      TABLE III
    __________________________________________________________________________
    Normal Vehicle Fill
    Operator Action
                  Controller Action LCD Display
    __________________________________________________________________________
     1                              "Insert Card In Card Reader To
                                    Begin Fueling"
     2 Insert Card
                  Validate Card     "Fill Vehicle Yes or No?
     3 Push YES Button              "Connect Hoses and Ground Wire,
                                    Push YES"
     4 Push YES Button
                  Verify DV-2 In Recirculation
                  Position
     5            Open DV-1
     6            Monitor DT-1 Until DT-1 is
                  <T.sub.start
     7            Start Pump
     8            Monitor DT-1 Until DT-1 is
                  <T.sub.fill
     9            Display User Prompt
                                    "Fuel Temp = ??? Push Yes To
                                    Fill or No To Abort"
    10 Push YES Button
                  Open DV-2 To Fill Position
    11            Calculate Gallons Pumped
                                    Real-Time Gallons Pumped
                                    Displayed
    12            Monitor Full Tank Condition
                                    --
    13            ?Increase In Pump Discharge
                                    --
                  Pressure?
    14            Open DV-2 To Recirculate Position
                                    Display Total Gallons Pumped
    15            Close DV-1        "Disconnect Hoses And Ground
                                    Wire And Enter Yes"
    16 Disconnect Hoses and
       Ground
    17 Push YES Button
                  Complete Transaction Record
                                    "Don't Forget Your Card"
    18            Signal Card Reader To Eject Card
    19            Reset For Next Fill
                                    "Insert Card In Reader To Begin
                                    Fueling"
    __________________________________________________________________________

                                      TABLE IV
    __________________________________________________________________________
    Normal TVAC Fill
    Operator Action
                 Controller Action LCD Display (Positive Response)
    __________________________________________________________________________
                                   "Insert Card In Card Reader To
                                   Begin Fueling"
     1 Insert Card
                 Validate Card     "Connect Hose From Truck,
                                   Ground Wire And Push YES"
     2                             "Top Fill = YES, Bottom Fill = NO"
     3 Push YES or NO
                 If YES go to STEP 4, if NO go to
                                   "Connect Hoses and Ground Wire
       Button    STEP 16           Connected, Push YES"
     4 Push YES Button             "Close V-1 and open DV-7 and
                                   Push Yes"
     5 Push YES Button
                 If YES. If NO, go to TIME OUT
     6           Verify DV-2 In Recirculation
                 Position
     7           Open DV-1
     8           Monitor DT-1 Until DT-1 Is
                 <T.sub.start
     9           Start Pump        "Top Fill Started Push Cancel
                                   To Stop"
    10 Push Cancel Button
                 Stop Pump         "Top Fill Stopped"
    11           Close DV-1        "Continue Filling YES or NO?"
    12 Push YES or NO
                 If YES Repeat Steps 2 and 3 and
       Button    Top or Bottom Fill Procedure
    13           If NO             "Open Valve V-1 and Push Yes"
    14 Push YES Button             "TVAC Fill Complete - YES OR
                                   NO"
    15 Push YES or NO
                 If NO Go To Step 2, If YES Go To
       Button    Step 22
    16           If No at Step 4
    17           Display Manual Instructions
                                   "Open Valve V-1 on TVAC and
                                   Press YES"
    18 Push YES Button
                 --                "Fill From Truck"
    19                             "Push CANCEL When Button Fill
                                   is Complete"
    21 Push YES or NO
                 If YES Go To Step 2. IF NO, Go To
       Button    Step 22
    22                             "Enter Gallons Filled"
    23 Push Numeric Keys           "???? Gallons Filled YES or
                                   NO?"
    24 Push YES or NO
                 If No Go To Step 22, If No Go To
       Button    Step 25
    25                             "Confirm Valves DV-7 is Closed
                                   and V-1 is Open and Enter YES
    26 Push YES Button             "Disconnect Hoses and Ground
                                   Wire, Push YES"
    27 Push YES Button
                 Complete Transaction Record
                                   "Don't Forget Your Card"
    28           Signal Card Reader To Eject Card
    29           Reset For Next Fill
                                   "Insert Card In Card Reader To
                                   Begin Fueling"
    __________________________________________________________________________

• Inventors
  Makel, Darby B.; Jansa, Earl D.; Cahill, Daniel V.; Bickmore, Timothy W.;
• Assignee
  Aerojet General Corp. (Sacramento, CA)
• Published
  Dec-17-1996
• Current US Classes:
  073/40
  073/40.5R
  340/5.92
  417/901
  700/283
  702/51
  705/413
• Application #
  297337
• International Classes
  F04B 015/08; G01B 021/00
• Field of Search
  364/509 364/510 364/478 364/464 364/465 340/626 340/605 340/825.31 73/40 73/40.5 417/901
• Examiner
  Trammell; James P.
• Agent
  Oblon, Spivak, McClelland, Maier & Neustadt P.C.
• US Patent References:
  4066095
  4088987
  4404843
  4658371
  4736193
  4740777
  4752698
  4835522
  5394336
  5411374