Vapor Extraction Units
INTRODUCTION
Determining the location of a leak in an underground gas line has long posed difficult problems for gas line repair crews. Although the gas line itself is easily located, the soil is often saturated, which makes it difficult to pinpoint the actual location of the leak. As a result, it has not been uncommon for large stretches of a surface, including paved roadways, to be excavated in a somewhat random fashion. This, of course, is costly and time-consuming. In addition, the continuous leaking gas creates a greater hazard the longer the leak continues.
HISTORY
The conception of the Vapor Extraction Unit (VEU) was developed by Atmos Energy. Their challenge was to remove residual gas quickly and safely, while monitoring the percent of gas in the moving air.
SOLUTION AND SUCCESS
An Integral LEL monitor alarms the operator when dangerous gas concentrations are approached. A bypass valve then allows the operator to configure the VEU as necessary. The VEU was so successful at removing residual gas that different applications were explored.
APPLICATIONS
Current applications include the pinpointing of leaks on cast iron pipes and residual gas remediation. Some use the VEU purely for pinpointing leaks. Accurate pinpointing has made "keyhole technology" viable, reduced "dry holes," and increased overall efficiency. Using the VEU for gas remediation allows businesses that may have residual gas underneath or around the foundation to promptly reopen – avoiding expensive downtime.
HOW THE VEU TRAVELS
Truck mounted units are used in the metroplex. Trailer mounted units are used in non-metro areas and are designed to be mobile from district to district.
US Patented
| VEU | |
|---|---|
| Weight | 1,430 lbs (648 kg) |
| Height | 47.5 in (113 cm) |
| Width | 43 in (109 cm) |
| Length | 65 in (165 cm) |
| Engine Option | Isuzu 3CH1 Tier IV |
| Recommended Engine RPM | 2850 rpm |
| Fuel Consumption | 1.0 max gal/hr |
| Fuel Tank Capacity | 8 gallons (30.2 L) |
| Blower | Tuthill 850 cfm |
| Recommended Vacuum | 6 in Hg |
| Maximum Vacuum | 15 in Hg |
| Operating Noise Level | 90-100 db |
| Gas Monitor | Industrial Scientific Itrans w/ LEL |
| Alarm Threshold | 35% LEL |
| Engine Stop Threshold | 50% LEL |
