WO1996033451A1

WO1996033451A1 - Chemical injection system

Info

Publication number: WO1996033451A1
Application number: PCT/US1996/005380
Authority: WO
Inventors: Stephen E. Marshall; Mark V. Zeck
Original assignee: Y-Z Industries Sales, Inc.
Priority date: 1995-04-18
Filing date: 1996-04-18
Publication date: 1996-10-24
Also published as: EP0886812A1; EP0886812A4

Abstract

A system (10) for injecting chemicals, e.g. odorants, from a chemical supply into a conduit or container (60) including three primary components, a pump (30) for injecting the odorant, a metering device (32) and a programmable controller (40). The controller (40) is preferably powered by a solar panel (12) to facilitate use of the system (10) in remote areas for long periods of time. A removable data carrier (84), such as a memory module, is connected to the controller (40) to collect odorant system (10) event data. The data carrier (84) is removable from the controller (40) and the data therein may be downloaded into an auxiliary audit computer (80) for generation of summary audit reports. The system (10) precisely monitors how much odorant is used per pump stroke and insures that the odorant injection rate remains constant irrespective of the environmental or equipment variations which might otherwise cause inaccuracies in the measurement of odorant usage data and/or the fluctuations of the odorant injection rate.

Description

CHEMICAL INJECTION SYSTEM

RELATED APPLICATION

This application is a continuation-in-part of U.S. Patent No.

5,406,970 filed June 25, 1 993.

TECHNICAL FIELD

The present invention relates generally to chemical injection

systems and more particularly to methods and systems for

monitoring and controlling the injection of odorants, corrosion

inhibitors, lubricants or other additives into gas and liquid conduits

and fluid container.

BACKGROUND OF THE INVENTION

Odor levels within gases or liquids are usually monitored by

several techniques, including the room test and the use of a dilution

apparatus such as an odor tester, odorometer or odorator. Although

there are various procedures involved in odor-level determination,

the most common mechanism used in the industry is the human

nose. Because the objective is to determine the actual degree of

odor, not the amount of odorant, the human olfactory sense

continues to serve as the standard of pungency.

SUBSTITUTE SHEET (RULE 2β) Systems for injecting odorants are well known in the prior

art. Such systems typically include a pump for injecting an odorant

into a system, and some timer or other controller to effect actuation

of the pump at predetermined

intervals. Because it is important to know the total volume of

odorant injected into a fluid system over the period of operation,

more sophisticated systems in the art include verification devices to

determine the quantity of odorant injected. One such injection

system, designated by the Model No. NJEX-7100 and offered by

the assignee of the present invention, included a

positive-displacement pump for injecting odorant into a pipeline, a

controller, a flow switch connected to the outlet side of the odorant

pump, and an odorant inlet meter for metering the odorant to the

pump. The controller tracked the flow rate of the gas in the

pipeline using a flow signal, and this signal was also used to

calculate the stroke rate of the pump. Monitoring was achieved by

the flow switch and the inlet meter. In particular, the flow switch

interfaced to a counter to provide a continuous readout of the

number of strokes, and the meter served as an additional monitor

by counting the number of times the meter was refilled. From the

number of strokes and a preset pump displacement setting (in

cc/stroke), the purported volume of odorant injected was calculated. The system also included appropriate alarm circuitry for

signaling the user in the event of a malfunction.

While injection systems such as described above provided

significant operational advantages and improvements over the prior

art techniques and devices, they provided somewhat "coarse"

odorant usage data. For example, such systems were not capable

of precisely monitoring how much odorant was being used per

pump stroke because despite the preset pump displacement setting,

the actual odorant displacement per stroke changed due to pump

efficiency variations, static pressure variations, check valve

performance variations, line debris and variations in the density of

the odorant. Such variations caused inaccuracies in the odorant

usage data, especially where the system was operating over long

periods of time and in harsh environmental conditions. While these

systems did provide quantitative raw data for analysis, adjustment

and accountability of the odorant usage, they did not have any

capability to present such data in any type of useful format to

facilitate audit or reporting of system operation. The systems,

although quite sufficient for their intended purpose, were also

costly and had to be operated by experienced personnel.

Accordingly, there remains a long felt need for improved

odorant injection systems which overcome these and other

problems associated with the prior art. BRIEF SUMMARY OF THE INVENTION

It is a primary object of the present invention to provide a

total system approach to chemical injection, metering and

monitoring to facilitate collection by pipeline operators and others of

detailed quantitative data for analysis, adjustment and

accountability.

It is further object of the invention to provide such an

injection system that is extremely reliable, requires little or no

maintenance, is solar-powered and which can be left unattended in

harsh environments.

It is still another object of the invention to provide an

injection system using a pump and a meter which precisely

monitors how much chemical is injected per stroke of the pump.

The system precisely monitors how much chemical is used per

stroke irrespective of pump efficiency variations, static pressure

variations, equipment performance variations, line debris and

variations in the density of the chemical, among other factors,

which variations or problems might otherwise cause inaccuracies in

the measurement of chemical usage data.

It is yet a further object of the invention to provide an

injection system using a pump and a temperature-compensated

SUBSTITUTE SHEET (RULE 28) chemical inlet meter which accurately measures and verifies the

amount of chemical injected.

It is still another important object of the invention to provide

a chemical injection system with an auxiliary audit system

comprising a detachable monitor module connected to the system

controller, and an audit computer. The module is designed to

collect chemical event usage data (e.g., the time and date of each

alarm, the time and date of system parameter changes, the actual

chemical injected, etc.) over a relatively long period of time, e.g.,

several months. The monitor module is removed from the system

controller at periodic intervals and the data therein downloaded into

the audit computer; alternatively, the monitor module may be

polled in the field over a telephone or other telecommunications

link. The usage data is processed in the audit computer to generate

useful displays or reports of injection system events.

It is a further object of the invention to provide in such a

system verification of pre-set proportional-to-flow odorization rates,

an easy, positive method of odorization documentation and system

monitoring and alarm functions capable of notifying the operator in

the event of a malfunction.

These and other objects of the invention are provided in a

system for injecting a chemical, such as an odorant, from a

chemical supply into a conduit or container. In one embodiment, the system comprises three primary components: a pump, a meter

and a controller. The pump has an inlet, and an outlet connectable

to a conduit or container. The meter supports a predetermined

volume of a chemical and has an inlet connected to receive the

chemical from the chemical supply and an outlet for delivering the

chemical to the inlet of the pump. The system also includes a flow

sensor that is placed within the conduit or container to continuously

monitor the actual flow rate of the gas or liquid. The meter

advantageously includes a transducer device for detecting chemical

level in the meter, including a low level condition, as well as a

temperature sensor for detecting temperature variations of the

chemical therein. According to one feature of the invention, the

transducer device continuously monitors the level of the chemical

being used and cooperates with the controller and other sensor

devices (including the flow sensor and the temperature sensor) to

insure that a predetermined pump injection rate is maintained substantially constant over an operating period (which may be

several days, weeks or months). As will be seen, the system

monitors how much chemical is used per stroke and insures that

the injection rate remains constant irrespective of such factors as

pump efficiency variations, static pressure variations, equipment

performance variations, line debris and variations in the density of

the chemical, which variations or problems might otherwise cause inaccuracies in the measurement of chemical usage data and/or the

fluctuation of the chemical injection rate.

According to another feature of the present invention, an

auxiliary audit computer is provided or suitably-programmed to

facilitate the processing and presentation of raw chemical usage

data collected from the injection system. The audit computer

cooperates with a monitor module and is designed to be connected

to the controller via an RS-232, parallel or similar interface. The

module includes appropriate storage devices, such as

electrically-erasable programmable read only memories, which store

data collected by the controller. Time stamp data is also provided

by the controller for the various system events (e.g., number of

pump strokes, amount of chemical injected in pounds, parameter

changes, gas flow, etc.) and stored in the module. Thus the

module provides a convenient store of the date and time of each

particular operational event in the system. If the available memory

in the module is used up, new data is preferably written over the

oldest data such that when the module is read only the most recent

usage data will be present.

Although not meant to be limiting, preferably the audit computer is a general purpose personal computer running a

Windows-based or other known type of graphical user interface.

The module preferably collects data from the controller over a period of time, such as several months. The module is removed

from the enclosure at periodic intervals and the data therein

downloaded to the audit computer. Alternatively, a telephone or

other suitable telecommunications connection can be provided to

enclosure to enable the collected data to be downloaded via a

telephone link or the like. The audit computer is suitably

programmed to receive the collected data and to calculate such

variables as hourly odorant usage (HOU), and daily odorant usage

(DOU) in the case of gas injection systems, load odorant usage

(LOU) in the case of liquid injection systems, the number of alarms

generated, the average odorant injection rate, the low and high

injection rates, the total odorant used, and the like. Based on such

information, the audit computer can then be controlled to generate

a table of such information, which can then be displayed on the

CRT of the computer or printed out on an associated printer device.

The foregoing has outlined some of the more pertinent

objects of the present invention. These objects should be

construed to be merely illustrative of some of the more prominent

features and applications of the invention. Many other beneficial

results can be attained by applying the disclosed invention in a

different manner or modifying the invention as will be described.

Accordingly, other objects and a full understanding of the invention may be had by referring to the following Detailed Description of the

preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention

and the advantages thereof, reference should be made to the

following Detailed Description taken in connection with the

accompanying drawings in which:

FIGURE 1 is an elevation view of the preferred support

structure of the invention for use in supporting the various

components of the injection system;

FIGURE 2 is an elevation view of the mechanical enclosure of

the system with an access door removed;

FIGURE 2A is a view of the odorant discharge manifold

connections;

FIGURES 3A and 3B are elevations, partially cutaway, of two

embodiments of an odorant meter;

FIGURE 4 is a detailed block diagram of the preferred odorant

injection system configuration of the invention;

FIGURE 5 is a block diagram of the auxiliary audit system of

the present invention; FIGURE 6 is a representative summary table of odorant usage

event data generated by the audit computer according to the

invention;

FIGURE 7 is a table of system alarm status data generated by

the audit computer according to the invention;

FIGURE 8 is a representative system parameter table

generated from the table in FIGURE 6;

FIGURE 9 is a representative system diagnostic table

generated by the audit computer; and

FIGURE 10 is a flow diagram illustrating the operation of the

system.

Similar reference characters refer to similar parts or steps

throughout the several views of the drawings.

DETAILED DESCRIPTION

The present invention describes a "chemical" injection

system wherein a chemical, such as an odorant, is injected into a

conduit, container or the like for enabling operators to determine

the presence of gas or liquid leaks. While the preferred

embodiment of the invention relates to "odorant" injection, it should

be readily appreciated by those of ordinary skill that the techniques

and systems of the invention are readily applicable to other

applications wherein it is desirable to inject a monitoring chemical

SUBSTTTUTE SHEET (RULE 26) into a fluid (whether liquid or gas) to thereby facilitate collection of

quantitative data for analysis, adjustment and accountability.

Examples of such alternative applications include, without

limitation, injection of corrosion inhibitors, fuel additives, lubricants

and other chemicals into pipelines or other gas or liquid conduits.

The present invention provides a total system approach to

chemical or odorant injection, metering and monitoring to facilitate

collection of detailed quantitative data. The injection system is

extremely reliable, requires little or no maintenance, is preferably

solar-powered and can be left unattended in harsh environments for

long periods of time. According to one important feature of the

invention, the system monitors how much odorant is used per

pump stroke and insures that the odorant injection rate remains

constant irrespective of environmental or equipment variations

which might otherwise cause inaccuracies in the measurement of

odorant usage data and/or the fluctuation of the odorant injection

rate.

Referring now to FIGURE 1 , an elevation view is shown of

the basic physical components of the system. As can be seen, the

system 10 is designed to be extremely portable and compact. The

system 10 is preferably mounted on a support pole 1 1 supported in the ground adjacent the conduit or container to be monitored.

Viewed from the top, the system includes a solar panel enclosure 1 2, a system control enclosure 14, a mechanical enclosure 1 6 and

an expansion tank 1 8. An odorant inlet filter assembly 20 is also

shown. Filter assembly 20 connects to an odorant source as will be

explained. One or more of the enclosures 1 2, 14, 1 6 and 1 8 may

be combined into a single integrated housing, and the solar panel

may be remotely located from the remainder of the system 10. Of

course, any suitable power source (such as A.C) may be used

instead of or to supplement the solar powered assembly. However,

since the system 10 is generally used outdoors in remote locations

and remains unattended, solar power is preferred.

The solar panel enclosure 12 supports a solar panel that

converts solar energy to electrical energy that is coupled to a

battery supported in system control enclosure 14 via electrical

connector 13. As will be described, the system control enclosure

supports the battery and a microprocessor- based controller unit for

controlling the operation of the system. Control and data signals are

routed between the controller unit and the mechanical enclosure 1 6

via the electrical connector 1 5. The mechanical enclosure 1 6

supports the various mechanical elements of the system used to

control odorant injection and metering. These elements include the

pump and odorant inlet meter as will be described. The expansion

tank 18 is designed to be mounted close to the mechanical

enclosure 1 6 and acts as a pressure source/receiver for the odorant

SUBSTTTUTE SHEET (RULE 26) inlet meter. The expansion tank includes a relief valve 1 9, a

pressure gauge 21 , a vent valve 23 and an expansion tank isolation

valve 25. The odorant meter is connected via conduit 27 to a

bottom port 29 of the expansion tank 18.

Turning now to FIGURE 2, a detailed view is shown of the

mechanical enclosure 16 with an access door removed. The

enclosure 1 6 supports two main components of the system 10, the

pump 30 and the inlet meter 32. As will be described in detail, the

pump 30 injects an exact quantity of odorant at a rate determined

by the controller unit. The meter 32 serves as a temperature

compensated meter which verifies the amount of odorant injected

by the pump.

The pump is preferably a pneumatically-actuated, positive

displacement, reciprocating plunger pump. The pump is actuated

with compressed air or conduit or container gas at a pressure of

about 40 psi. The pump has an adjustable displacement of 0-8.0

cc. and achieves proportional-to-flow injection through adjustment

of the stroke rate. One such pump is described in U.S. Patent No.

5,032,063, which is incorporated herein by reference, assigned to

the assignee of the present invention and sold under the Model No.

NJEX 7000. Each time the pump is stroked, a plunger displaces

hydraulic fluid against a pump diaphragm which in turn displaces

odorant through a discharge check valve. The pump diaphragm

SUBSTITUTE SHEETfRULE 26) acts as an isolation device between the hydraulic fluid and the

odorant, minimizing the risk of odorant escape. While this

particular pump offers significant advantages and is preferred, it

should be appreciated that any type of positive displacement pump

can be used for the pump 30 of the system 10.

Referring briefly to FIGURE 3A, an elevation view, partially

cutaway, is shown of a first embodiment of the odorant meter 32.

As noted above, this device is used to meter a predetermined

amount of odorant and to provide the controller unit with

information about how efficiently the pump 30 is pumping. The

meter is refilled after a predetermined amount of odorant is metered

thereby to the pump. To this end, the meter includes a central

stem 22 upon which a float 24 is mounted. The float is designed

to ride on the stem as to track the volume of odorant in the meter.

Movement of the float to a predetermined lower position will

generate an electrical signal identifying that the meter needs. to be

refilled. As will be described, this signal is delivered to the

controller, which in turn activates several valves to cause refilling of

the meter from the odorant supply. The meter 32 advantageously includes a detection device

such as a level transducer 28a for continuously monitoring the level

of odorant in the meter and generating an electrical signal

proportional thereto. One suitable transducer is a linear displacement transducer (LDT) made by MTS of Research Triangle

Park, North Carolina, although any suitable displacement

transducers may be used. A temperature sensor 28b is also

provided for generating an electrical signal proportional to

temperature of the odorant within the meter. One suitable device is

a two terminal monolithic integrated circuit temperature transducer

(e.g., Model AD592 from Analog Devices) that provides an output

proportional to absolute temperature. As will be described, the

signals from the transducers 28a and 28b are provided to the

controller unit to facilitate the calculation of the actual amount of

odorant provided per pump stroke and to insure that the pump

injection rate is maintained constant despite variations in pump

efficiency, flow rate variations, odorant density fluctuations, line

debris and other environmental, mechanical, hydraulic and electrical

disturbances.

Referring now to FIGURE 3B, a cross-sectional view of a

second embodiment of the odorant meter 32 is shown. This meter

32 is used for containing a smaller volume of odorant than is

possible by the embodiment illustrated in FIGURE 3A. The smaller

volume of odorant enables a higher degree of accuracy in the

measurement of injected odorant. The meter 32 includes a float

chamber 33 and sensor chamber 35 separated by a thin wall 37.

Within the float chamber 33, a cylindrical magnet/float assembly 39

SUBSTTTUTE SHEET (RULE 26) raises and lowers in response to the level of the chemical odorant.

A level transducer 28a similar to that discussed with respect to

FIGURE 3A is inserted into the sensor chamber 35 and interacts

with the magnet 39a of the magnet/float assembly 39 to generate

signals indicative of the odorant level within the float chamber 33.

Movement of the float 39b to a predetermined lower position will

cause generation of an electrical signal indicating that the meter 32

needs to be refilled. A temperature sensor 28b as described with

respect to FIGURE 3A, will provide signals indicating the

temperature of the odorant within the meter 32.

Referring briefly back now to FIGURE 2, the odorant inlet

filter assembly 18 is located below the enclosure 16 and filter's the

system's odorant supply. Assembly 1 8 also supports an odorant

filter element and an odorant return valve. The mechanical

enclosure 16 also includes several other components including a fill

valve 34, an actuation gas manifold 36 and an odorant discharge manifold 38. The fill valve 34 controls odorant flow into the meter

32.

The actuation gas manifold 36 houses an actuation gas

supply connection and a pneumatic exhaust connection for the

system. Actuation gas for the pump 30 may be provided by a local

source such as the conduit or container or from a source of

compressed air. The manifold also supports a pair of solenoid

SUBSTTTUTE SHEET (RULE 26) valves 33a-b. One valve actuates the fill valve 34 via the conduit

37 and the other valve actuates an air relay valve 35 which in turn

activates the pump 30 via conduit 39 to discharge the odorant. By

using the solenoid valve and the air relay valve in series to stroke

the pump, the advantages of low power consumption and rapid

actuation gas delivery are provided by the system.

The odorant discharge manifold 38 has two inlet connections

43a and 43b. Inlet 43a receives pump discharge via conduit 45.

Inlet 43b is connected to the meter 32 via conduit 47. The odorant

discharge manifold 36 includes three outlet ports 49a-c, shown in

the partial side view in FIGURE 2a. Port 49a receives a bypass

conduit 51 connected between the port and an outlet 53 of the

odorant inlet filter assembly. Port 49b is the pipeline connection

pipe which delivers the pumped odorant to the pipeline. Port 49c

receives the conduit 27 (shown in FIGURE 2) connected between

the port and the expansion tank bottom port 29. As seen in

FIGURE 2, the odorant discharge manifold 36 includes a valve 57a for controlling the flow of the odorant through the manifold. A

purge valve is also provided. These valves are normally closed.

Referring now to FIGURE 4, a detailed schematic diagram is

shown of the system. Components previously identified are

designated with the same reference numerals. Operation of the

systems centers around the three primary components: pump 30, meter 34 and controller unit 40. The controller unit 40 is preferably

a digital controller having a digital signal processor 42, suitable

random access and read only memory 44, display 46, keyboard 48

and suitable input/output connections. The processor operates

under the control of a software program to effect the various

control functions described below. One of ordinary skill in the

computer programming art may program the digital processor,

using conventional programming languages, to provide these

functions. Other input/output devices, such as a printer, may also

be provided if desired.

The controller unit is powered by the solar panel assembly 1 2

through the battery. Alternatively, a charger unit 50 may be

provided for direct electrical power through a conventional A.C.

outlet. The controller unit 40 receives a flow input signal from

either a flow computer (not shown) or some other flow monitoring

device such as a differential pressure transducer. One such

transducer is sold by Rosemount of Eden Prairie, Minnesota. The

controller unit has two outputs 52a-b, and one input 53 provided

by the meter 32. Output 52b generates a control signal to control

solenoid valve 33b, which actuates fill valve 34 via the conduit 37.

Output 52a generates a control signal that actuates solenoid valve

33a, which controls air relay valve 35; this in turn activates the

pump 30 via conduit 39 to stroke the pump to discharge the

SUBSTTTUTE SHEET (RULE 26) odorant. A regulated actuation gas supply (between 40-50 psi)

such as instrument air or pipeline air is supplied to the valves 33a

and 33b to control the fill valve and the pump.

As also seen in FIGURE 4, the odorant supply is passed

through an inlet filter 54, through the fill valve and into the odorant

meter. The inlet filter and an odorant return valve 55 are supported

in the filter assembly 18. The meter also includes an odorant filter

56, through which the odorant passes on its way to the pump 20.

Odorant is delivered to the pump 20 from the meter via conduit

59. The odorant is preferably injected into the conduit or container

60 via an odorant injection probe 62. The probe 62 includes a

gauge 63, a check valve 64, a pressure relief valve 65, and a

normally open valve 66. The remainder of the connections have

been previously described. When the pump is actuated (via valves

33a and 35), a predetermined amount of odorant is provided to the

probe 62 and then to the pipeline.

In particular, during normal operation the pump 30 injects an

exact quantity of odorant at a rate determined by the controller unit

40. The quantity of odorant injected per stroke is set by the

operator using a volume adjustment knob located on the front of

the pump. The rate at which the pump is actuated is determined

by the controller. More specifically, the controller unit 40 allows

the system to operate in either a time-based mode or a

SUBSTTTUTE SHEET (RULE 26) proportional-to-flow mode. In the time-based mode of operation,

the controller actuates the pump at a regular time interval preset by

the operator. In the proportional-to-flow mode of operation, the

controller uses the flow rate input signal and several operator input

values to calculate the time between strokes of the pump. These

operator input values or parameters are entered via the controller

keyboard in a conventional manner (such as through use of a

prompting scheme or operator instructions). These values include,

without limitation, the desired injection rate (Ibs/MMSCF) or

(lbs/1 OKgal), the pump displacement (cc/stroke), and the odorant

density (lbs/gal). The injection rate is the desired amount of

chemical (xx.xx lbs.) to be injected per million standard cubic feet

of gas. The pump displacement is the amount of chemical

displaced (xx.xx cc) at each stroke of the pump. The chemical

density is the weight in lbs of one gallon of chemical being injected

at 20 degrees centigrade.

According to the present invention the injection system is

used to inject the chemical, e.g., the odorant, into the gas pipeline at a predetermined rate which as noted above is preferably set in

pounds per million standard cubic feet (MMSCF) of gas or at

pounds per ten thousand gallons (lbs/1 OKgal) of liquid.

Significantly, during the proportional- to-flow operation, the

controller unit allows the system the ability to maintain the set

SUBSTTTUTE SHEET (RULE 26) injection rate even though there are variations in gas pipeline flow,

odorant density, actual pump displacement or other such variations.

This operation can be seen by considering the following formula:

Pump Stroke Rate (sec/stroke) =

Pump Displacement x Chemical Density x (.951 123) (cc/stroke) (lbs/gallon)

Injection Rate x Actual Flow Rate

(Ibs/MMSCF) or (MMSCF/hr) or (lbs/1 OKgal) (lbs/1 OKgal)

The Injection Rate, the Pump Displacement and Chemical Density

are user-settable parameters. The Actual Flow Rate is sensed by

the flow monitoring device in a conventional manner. The value

(.951 1 23) is a conversion constant.

As can be seen by solving the above equation for Injection

Rate, it is possible to selectively alter, or adjust for variations in,

one or more other variables to insure that the Injection Rate can be

maintained constant. This is one of the important functions of the

controller unit of the present invention. Thus, for example, as

temperature variations sensed by sensor 28b alter the Chemical

Density of the odorant, the Injection Rate changes (assuming all

other variables remain constant). Likewise, variations in the Actual

Flow Rate alter the Injection Rate (if all other variables remain

constant). Further, using transducer 28a the controller unit

monitors the actual odorant leaving the meter and compares this value to the preset Pump Displacement to determine the actual

Pump Displacement, which may vary over time due to pump

efficiency variations or the like. Thus while the Pump Displacement

may be set for 1 .0 cc/stroke, the comparison of the transducer 28a

output and the expected pump output (measured in number of

strokes x the preset Pump Displacement) might indicate some

variation in the actual Pump Displacement. This variation will also

impact the Injection Rate (all other variables being constant).

Thus according to the invention the controller unit continually

monitors the actual Pump Displacement (as calculated by

comparing the transducer 28a output and the expected pump

output), the Chemical Density (as calculated from the transducer

28b output), and the Actual Flow Rate, and in response thereto

generates a control signal for controlling the rate at which the pump

is stroked to thus maintain the preset injection rate. By using the

actual odorant value and correcting for temperature (and thus

density) and flow rate variations, the controller provides dynamic

and real-time control over the injection system which has heretofore

been unavailable in such systems.

The flow input signal is provided by either a flow computer

or other flow monitoring device. In the proportional-to-flow

operative mode, the controller 40 distinguishes between a low flow

situation and a loss of flow input signal. In the event of a loss of flow signal, the controller unit automatically defaults back to a

preselected percentage of the flow input. The flow input signal is

read by the controller preferably eight times per pump stroke.

These readings are averaged and the time duration until the next

stroke is then calculated by the controller.

The meter 32 thus advantageously serves to meter the

odorant into the pump and also to monitor the actual pump

displacement. This is achieved through the level transducer 28a

which measures the exact odorant displaced from the meter, a

value which can then be continuously compared to the expected

pump output (in preset cc/strokes x a number of strokes) to

determine the true pump efficiency over a period of time. By

monitoring true pump displacement that varies over time (as well as

odorant density and actual flow rate), the system compensates for

environmental and other factors by altering the stroke rate of the

pump to maintain the preset injection rate constant. The meter 32

serves as a monitoring and metering device which facilitates the

verification of the actual amount of odorant injected by the pump, and this value is then selectively and continuously used to alter the

pump stroke rate as needed.

The controller unit 40 receives the various signals at input 53

from the meter provided over the electrical connector 68, which

preferably includes a number of conductors. One conductor is

8UBSmTUTE SHEET (RULE 26) connected to the meter level transducer and signals the controller

unit when the odorant level has fallen below a predetermined level.

As noted above, the controller responds to this condition by

actuation of solenoid valve 33a and the fill valve. The other

conductors are connected to the level transducer 28a and the

temperature transducer 28b. These signals are provided to the

controller to facilitate precise calculation of the odorant injected as

described above.

Thus the invention facilitates the calculation of the precise

amount of odorant injected. Prior art systems merely provided a

coarse value for the odorant injected because they did not take into

consideration the effects of pump efficiency variations, flow rate,

temperature and the like.

As also seen in FIGURE 4, the upper portion of the meter is

connected to the gas expansion tank to enable gas, which would

otherwise be entrained in the odorant, to bubble off. The entire

odorant injection system thus operates in a closed loop manner to

provide precise control of odorant injection, metering and

monitoring. This closed loop operation is provided because as the

meter (which is a sealed tube) is filled, the air within the meter is

delivered into the expansion tank. As the odorant level is

decreased, the displaced air is drawn back into the meter to

maintain a static pressure.

SUBSTTTUTE SHEET (RULE 26) According to another important feature of the present

invention, the system include an auxiliary audit system which

operates in conjunction with the controller unit to facilitate accurate

and detailed reporting of how the system has operated over an

extended period of time. The audit system 80 is shown

schematically in FIGURE 5 and includes an audit controller 82 and a

removable monitor module 84. Module 84 is designed to be

connected to the controller unit 40 via an RS-232, parallel or similar

interface 85. The module includes appropriate storage devices,

such as electrically-erasable programmable read only memories,

which store data collected by the controller unit 40. Time stamp

data is also provided by the unit 40 for the various system events

(e.g., alarms, total pump strokes, total pounds injected, etc.) and

stored in the module. Thus the module provides a convenient store

of the date and time of each particular operational event in the

system. If the available memory in the module is used up, new

data is preferably written over the oldest data such that when the

module is read only the most recent usage data will be present.

Although not meant to be limiting, preferably the audit

controller 82 is a general purpose personal computer running an

MS-DOS operating system with Microsoft Windows Version 3.1 or

other graphical user interface. Such a computer system is well

known and provides a convenient graphical user interface (GUI) that

SUBSTTTUTE SHEET (RULE 26) cooperates with point and click or keyboard input devices in a well-known manner.

The module 84 preferably collects data from the controller

unit 40 over a period of time, such as several months. The module

is removed from the enclosure at periodic intervals and the data

therein downloaded to the audit controller. Alternatively, a

telephone or other suitable telecommunications connection can be

provided to the enclosure to enable the collected data to be

downloaded via a telephone link or the like. In the case of a

telephone link, a modem is provided as is well known. The memory

module may be integrated into the controller unit 40 instead of

being a replaceable device. The audit controller is suitably

programmed to receive the collected data and to calculate such

variables as hourly odorant usage (HOU), daily odorant usage

(DOU), load odorant usage (LOU), the number of alarms generated,

the average odorant injection rate, the low and high injection rates,

the total odorant used, and the like. Based on such information,

the audit controller can then be controlled to generate a table of

such information, which can then be displayed on the CRT of the

computer or printed out on a printer device. A hard disk, CD-ROM or other storage device is used to maintain the data (in raw or table

format) to provide an audit trail for reporting purposes. The tables generated by the audit controller may be

manipulated in a variety of fashion to optimize the usability of the

table displays to a user. One example of a means of manipulation

of said table is a setup selection function enabling a user to adjust

the tables to display only the odorant usage data by the system be

it either daily odorant usage or load odorant usage data or to

display only event data in the tables. The odorant usage data

describes the odorant usage for a particular unit of measure, and

the event data describes alarm data, parameter change data,

system change data, etc. When only the odorant usage or event

data are displayed, a prompt is included at the top of the table to

indicate this condition.

By way of example only, one such table generated by the

audit controller is shown in FIGURE 6. This report summarizes the

data for a particular period defined by log start and end dates. By

using function keys on the keyboard, the user can select different

days or tag certain fields. For example, with the cursor located

adjacent the DOU field, depression of the F1 function key allows

the user to pull down a window showing HOU for the particular

day. Depression of the F2 function key allows the operator to

select a different date to generate a new table. Depression of the

F3 key enables the operator to view the time and date of the next

alarm condition after the day shown. An example of a system alarm status screen is shown in FIGURE 7. A user is more easily

able to ascertain the system alarm whose condition has most

recently changed due to a status marker 100 indicating that the

status of an alarm has changed (e.g., turned on or turned off) from

the previously recorded time period. If the F4 key is depressed, a

window is created to allow the operator to view the system

parameters for the time period in question. An example of a

system parameter screen display is shown in FIGURE 8.

The audit controller is also programmed to generate a table of

diagnostic information from the collected data to assist with

troubleshooting of the odorant injection system. A parameter

selection table enables selection of particular parameters for

viewing. The parameters may be individually selected or a number

of default values may be selected. Examples of parameters within

the diagnostics selection table would include: flow voltage,

expansion tank pressure, verometer %, battery voltage, display

temperature, odorant temperature, pump displacement, flow % and

odorant tank %. This list of diagnostic parameters is, of course,

merely illustrative and any other parameters suitable for various

chemical injection systems would be sufficient for purposes of the

diagnostic table. A diagnostic table, as shown in FIGURE 9,

provides information concerning the selected diagnostic parameters

for various time periods within the system. With this table,

SUBSTTTUTE SHEET (RULE 26) systems problems may be tracked based upon the diagnostic

parameters.

The above-identified display screens are merely exemplary.

The raw odorant usage data may be processed into any suitable

record format to facilitate the presentation of the summary data.

Referring now to FIGURE 10, there is illustrated a flow

diagram illustrating the general operation of the chemical injection

system of the present invention. As can be seen from FIGURE 10,

the system's major components comprises the system software

102 and the odorization system 104. Initially, the odorization

system information parameters are entered at step 106 into the

module set up of the system software. The monitor module 84 is

then initialized at step 108 to create a log file for a particular

odorization system 104. A log file comprises the overall monitoring

history for a particular odorization system 104. Next, a cleared

, monitor module 84 is inserted at step 10 into the odorization

system. The module 84 monitors at step 1 1 2 the odorization

system for a predetermined period of time. An individual may then

retrieve at step 1 14 the monitor module data from the odorization

system 104 by physically interchanging the module with a cleared

module or accessing the data within the module over a

communications interface. The module data is downloaded into the

odorization software 1 02 at step 1 1 6 to create a module file. A

SUBSTTTUTE SHEET (RULE 26) module file contains all of the data retrieved from a module. The

module file may be viewed at step 1 18 by a user to determine

whether or not the module file should be appended at step 120 to

the log file for the odorization system 104. If the module file is not

to be appended to the log file, the monitor module is cleared at step

1 22 and may be reinserted into the odorization system at step 1 14

by physically placing the module in the system or instructing the

module to continue system monitoring over the communications

interface. Otherwise, the module file is appended to the log file at

step 1 24 before clearing the module at step 122. The log file may

then be used at step 126 for a variety of purposes, including

printing out reports generating text files or creating a permanent

report of the odorization system operation.

It should be appreciated that the use of a dedicated audit

controller provides significant audit and reporting capabilities for the

system. The user can generate individual reports for each day of

monitoring, and these reports can be manipulated and stored for

future audit or reporting use. Precise hourly and daily odorant use

data can be calculated, displayed and recorded to enable the

operator to know exactly how the system is operating in the field.

The invention thus facilitates the primary objectives of all gas

odorization programs, namely to provide for the public welfare and

safety, and to meet or exceed regulatory requirements.

SUBSTTTUTE SHEET (RULE 26) 31

It should be appreciated by those skilled in the art that the

specific embodiments disclosed above 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.

SUBSTTTUTE SHEET (RULE 26)

Claims

CLAIMSWhat is claimed is:

1. A system for injecting a chemical from a chemical

supply into a fluid containing system at a desired injection rate,

comprising:

a pump having an inlet, and an outlet connectable to

the fluid containing system, the pump having an adjustable stroke

rate;

a meter supporting a predetermined volume of the

chemical and having an inlet connected to receive the chemical

from the chemical supply and an outlet for delivering the chemical

to the inlet of the pump;

a level transducer for continuously monitoring a level

of the chemical in the meter and generating a chemical level signal

proportional thereto; and

controller operative under the control of a program

stored therein and responsive to the chemical level signal for

generating a control signal for selectively altering the stroke rate of the pump to maintain the injection rate substantially constant over

a predetermined time period.

SUBSTTTUTE SHEET (RULE 26)

2. The chemical injection system as described in Claim 1

further including;

a flow rate transducer located in the fluid

containing system for generating a flow rate signal proportional to

the flow rate of the fluid in the fluid containing system; and

wherein the controller is also responsive to the flow

rate signal to generate the control signal.

3. The chemical injection system as described in Claim 1

further including;

a temperature transducer located in the meter for

generating a temperature signal proportional to the

temperature of the chemical in the meter; and

wherein the controller is also responsive to the

temperature signal to generate the control signal.

SUBSTTTUTE SHEET (RULE 26)

4. The chemical injection system as described in

Claim 1 further including;

a flow rate transducer located in the fluid containing

system for generating a flow rate signal proportional to the flow

rate of the fluid in the fluid containing system;

a temperature transducer located in the meter for

generating a temperature signal proportional to the temperature of

the chemical in the meter; and

wherein the controller is also responsive to the

flow rate signal and the temperature signal to generate the control

signal.

5. The chemical injection system as described in Claim 1

further including an audit system for collecting chemical usage

data.

6. The chemical injection system as described in Claim 5

wherein the audit system includes a memory module for storing

chemical injection event data, and an audit controller.

7. The chemical injection system as described in Claim 1

further including means for supplying electrical energy to power the

controller.

SUBSTTTUTE SHEET (RULE 26)

8. The chemical injection system as described in Claim 4

wherein the means for supplying electrical energy is a solar panel.

9. The chemical injection system as described in Claim 1

further including an expansion tank connected to the meter.

10. An system for monitoring the injection of a chemical

from a chemical supply into a fluid containing system by a pump

responsive to a controller, the apparatus comprising:

a memory module connectable to the controller for

collecting chemical usage data over a predetermined period of time;

and

an audit computer for receiving the chemical usage

data collected by the memory module and including:

program control means for processing the chemical

usage data to generate audit information including at least one of

the following data types for the predetermined period of time:

chemical usage data for selected time periods, chemical injection

rate data, and alarm date; and

means for displaying at least some of the audit information in

the first display format.

SUBSTTTUTE SHEET (RULE 26)

1 1. The system of Claim 10 further including interface

control means for selecting a data type while the audit information

is displayed in the first display format and in response thereto

displaying some other of the audit information in a second display

format.

12. The system of Claim 1 1 wherein the second display

format includes a listing of only chemical usage data.

13. The system of Claim 1 1 wherein the second display

format includes a listing of only event data.

14. The system of Claim 1 1 wherein the second display

includes a listing of alarm status data.

15. The system of Claim 14 wherein the second display

format further includes an indication of recently changed alarm

data.

16. The system of Claim 10 wherein the chemical usage

data comprises load odorant usage (LOU) data.

SUBSTTTUTE SHEET (RULE 26)

17. The system of Claim 16 wherein the second display

format includes diagnostic data indicating system operating

conditions.

18. A method for monitoring the injection of a chemical by

a pump system into a fluid containing system, the method

comprising the steps of:

collecting chemical usage data from the pumping

system;

processing the collected chemical usage data to

generate audit information including at least one of the following

data types: chemical usage for selected time periods, chemical

injection rate data, and alarm data; and

displaying at least some of the generated audit

information in a first displaying format.

19. The method of Claim 18 further including the steps of:

selecting a data type while the audit information is

displayed in the first display format; and displaying the selected data type in a second display

format in response to the selection.

SUBSTTTUTE SHEET (RULE 26)

20. The method of Claim 1 8 wherein the fluid containing

system comprises a gas pipeline and the chemical comprises an

ordorant.

SUBSTTTUTE SHEET (RULE 26)