The following are types of valves engineers should know about: ARV or ARC valves ARV (Automatic Recirculation Valves) and ARC (Automatic Recirculation Control) although they can be used for many purposes, they are primarily used in centrifugal pumps to ensure that the predetermined flow is constant at all times. The main challenge with these valves is overheating, and it could be solved by keeping minimum flow throughout because dry valves are easily damaged.
Crude oil, refined petroleum products and other liquids are often transported by pipeline. Examples are gasoline, jet fuel, diesel, residential oil, carbon dioxide, anhydrous ammonia, and other hazardous liquids.
Many oil pipelines transport different types of oil in a single pipeline. To do this, operators send different products in batches. For example, an operator could convey gasoline for several hours, then change to jet fuel before changing to diesel.
Some pipelines carry highly volatile liquids that pass rapidly from a liquid to a gaseous state when leaking from a pipeline under pressure. Examples of these types of liquids are carbon dioxide, anhydrous ammonia, propane and many others.
Since pipelines are generally underground, signs are used to indicate the presence of pipelines in a location near the pipeline route. Of the three types of pipelines typically buried underground – pipelines for transportation, distribution, and collection – only transport pipelines are reported on the surface.
There are some signsb that indicate the route of the transportation pipelines.
The signs indicate that a transportation pipeline is in the vicinity, indicates the product being transported and provides the name and telephone number of the pipeline company. The signs are located at frequent intervals along the rights-of-way for natural gas transmission pipelines and hazardous liquids. They are also located at important locations, such as where pipelines intersect streets, highways, railways or streams.
Indications of leaks or ruptures in a pipeline
Releases can range from relatively minor leaks to catastrophic disruptions. It is important to remember that gases and liquids react differently once they are released from a pipeline. Generally, the following signs may indicate a leak or a break in a pipeline:
A whistling noise of escaping air, a loud rumble or a sound like an explosion
Flames emerging from the ground or water (possibly very large flames)
A dense fog, mist or cloud of steam
Debris, soil, dust or water thrown into the air from the ground
Liquids that flow from the soil forming bubbles, or the formation of bubbles in water
The peculiarly powerful odor of rotten eggs, skunk or oil
Dead or discolored vegetation, or discolored snow, above a right-of-way
A puddle of oil or an “oily reflection” on living or quiet water.