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An electric power generating station required a tank level measurement system to prevent the overfilling of remote storage tanks during tank truck deliveries of sulfuric acid, hydrochloric acid and sodium hydroxide. A Teflon coated radar gauge utilizing microwave pulse technology was selected for two tanks because it combined simple installation and calibration, high accuracy, low maintenance, and was able to withstand the corrosive environment. A bubbler type system was used on a third tank to interface with existing piping and an existing computer system. Customized tank strapping tables were created to convert the 4 to 20 mA level signal to a readout in gallons on panel meters at the truck unloading station. The level signals were also available to be sent to a control room for remote monitoring. In addition to the readout in gallons, the panel meter alarm relays trigger a signal tower with three lights and a horn for a visual and audio indication of the storage tank status during the filling operation. For information about the products in this system, visit our Products or Types of Products pages from the Site Map or contact us about the products or system of interest. |
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A critical measurement for a power plant is the amount of steam being
sent and billed to its customers.
The above system uses a vortex flow meter for volume measurement of the steam flow. The meter's 4 to 20 mA output is sent to a flow computer. A pressure transmitter output and an RTD output are also sent to the flow computer. The computer applies the three inputs in a mass flow equation and displays the resulting mass flow rate in pounds per hour and a total in pounds supplied. The rate and total are corrected for any changes in the temperature and/or pressure. This method insures an accurate steam flow and total measurement because it is pressure and temperature compensated. The system is powered by an uninterruptible power supply that insures that the steam flow measurement continues even when main line power is not available. Audible and visual alarms are also included to warn the control room and local personnel about loss of power to the system and any out of normal parameters, such as high flow, no flow, high or low temperature or pressure, etc. In addition to the computer's standard 4 to 20 mA output, a modem is also connected to a phone line via an RS232 connection for remote monitoring from a central office location. Isolation valves between the pressure transmitter and the main steam line are used to isolate the transmitter for calibration or service. For information about the products in this system, visit our Products or Types of Products pages from the Site Map or contact us about the products or system of interest. |
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A consumer goods processing plant required a system that would add a specific amount of water to a chemical blending operation every time it was started. A turbine style water meter with an electronic pulse output was installed upstream of two solenoid valves as shown above. The pulse signal from the flowmeter was sent to a batch controller. Two sizes of valves were used to control the water flow, one was 1 inch, the same size as the pipe diameter and one was 3/8 inch, approximately 30% of the pipe diameter. The total amount of water required for a batch is programmed into the controller. When the start button on the controller is pushed, both solenoids open and the flow rate and total are displayed. The volume of liquid is counted and totaled by the controller. At a specified preset amount, usually 95% of the total liquid required, the controller closes the larger solenoid valve leaving the smaller solenoid valve open. The smaller solenoid valve reduces the flow of water in the operation to insure a more precise shutoff at the exact amount of water required by the batch process. In addition, the smaller solenoid valve helps avoid water hammer in the piping when the valve closes to shut off the flow. With the wide range of materials available for valves and flowmeters, other liquids can be controlled with this system as well. For information about the products in this system, visit our Products or Types of Products pages from the Site Map or contact us about the products or system of interest. |
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