Data processing: generic control systems or specific application – Specific application – apparatus or process – Chemical process control or monitoring system
Reexamination Certificate
1997-08-18
2001-03-27
Cosimano, Edward R. (Department: 2161)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Chemical process control or monitoring system
C048S195000, C137S003000, C137S088000
Reexamination Certificate
active
06208913
ABSTRACT:
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.
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 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 i
Marshall Stephen E.
Zeck Mark V.
Cosimano Edward R.
YZ Systems, Inc.
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