Fueling Station Inventory Management Remote Tank Level Monitoring ATGs Fuel System

Underground storage tank monitoring systems

ATGs use probes to monitor both fuel and water height. Most underground tanks will have some water at the bottom and regulations require that you maintain less than 1 inch of water in the tank at all times. Probes are accurate to 1/1000 of an inch for level measurements. These probes also measure temperature. Knowing the fuel temperature is important because fuel expands and contracts with temperature changes. The warmer the fuel, the larger the volume change. For example, a 1 degree Fahrenheit rise in a 10,000-gallon gasoline tank will increase the volume by 7 gallons.

The space between the inner and outer walls of a double-wall tank is called the interstitial or annular space. A probe placed in a dry interstitial space checks for fluid that is either leaving the inner wall or entering from the outer wall. Some fiberglass underground tanks interstitial space is filled with brine or glycol and a probe is used to measure a drop in fluid level. A level drop would indicate that the interstitial fluid has either left the outer wall of the tank or mixed with the product in the inner wall. Either of these cases indicate a leak to the ATG connected to this probe.

Feature

ATG Applications

Gas Stations

Each sensor is connected to the ATG through an intrinsically safe set of wires. These wires must be incapable of producing heat or spark that would ignite fuel vapors. Intrinsically safe devices are low voltage circuits that protect the sensor wiring from producing a short and igniting fuel in the tank or sumps. ATGs are constantly monitoring the sensors installed at the site. These systems are also capable of shutting down dispensers, reducing the flow of in-tank pumps, and notifying the owner/operator that a problem has been detected. Methods of notification include text, email, fax, or external polling systems like a facility security alarm. ATGs are initially programmed by the tank service company to provide alerts at specific thresholds. Owners can specify a product level in inches or gallons that trigger a notification to a fuel delivery company. When the delivery is made the ATG measures the new level and provides a delivery report of inches and volume gained. In gasoline service stations, this volume is compared against sales at each pump, to reconcile the difference in the volume gained versus the fuel that was dispensed at the time of delivery.

Generators

ATGs are capable of monitoring levels and providing leak alarms but they also provide control of pumps. In the case of a generator where the fuel is supplied from a 110-gallon day tank or base tank, if the fuel level drops in the tank, the ATG can energize a transfer pump that will refill the day or base tank from a larger underground or aboveground tank.

Fuel dispensers have meters that measure the amount of fuel being pumped. ATG’s can indicate that a meter may be out of calibration if the inventory does not match the dispensed volume.

Oil Water Separator System

ATGs can be configured to monitor the oil level that accumulates in an oil-water separator system (OWSS). The OWSS collects rainwater and separates out oil and other hydrocarbons before discharging clean water to storm drains. An ATG is used to notify the owner or waste management company to remove the accumulated oil when it reaches a certain thickness or depth in the tank.

Installation: