Gas pump
From Wikipedia, the free encyclopedia
A gas pump is a machine at a gas station that is used to put gasoline in vehicles. Gas pumps are also known as petrol pumps, fuel dispensers or (in Australian usage) petrol bowsers.
A modern gas pump consists of two main parts: an electronic "head" containing an embedded computer to control the action of the pump, drive the pump's displays, and communicate to an indoor sales system; and secondly, a mechanical section containing an electric pump and valves to physically pump the fuel. Fuel flow is measured by one or more rotary encoders which generate electrical pulses. In some cases the actual pump may be sealed and immersed inside the fuel tanks on a site, in which case it is known as a submersible pump.
Older gas pumps have reeled meters, moving wheels with numbers on the side, which are physically connected to a turbine in the fuel flow.
A modern gas pump will often contain control equipment for the vapor recovery system, which prevents gasoline vapor from escaping to the air.
Since gas pumps are the focal point of distributing fuel to the general public, and fuel is a hazardous substance, they are subject to stringent requirements regarding safety, accuracy and security. The exact details differ between countries and can depend to some extent on politics. For example in countries fighting corruption, gas pumps may be more stringently monitored by government officials, in order to detect attempts to defraud customers.
Typically, individual pumps must be certified for operation after installation by a government weights and measures inspector, who tests that the pump displays the same amount that it dispenses.
Gas pumps are made by many different companies throughout the world. Three of the largest are Tokheim, Gilbarco-Veeder Root, and Dresser Wayne. Much consolidation has occurred in this industry, so that many formerly well-known names such as Schlumberger and EIN no longer exist as independent companies.
