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Address: No.4 Xuesong Rd, Hi-New Technology Industry Development Zone, Zhengzhou City, Henan Province, P. R. China,450001
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Tel/Whatsapp: 86-13700884564
E-mail: [email protected]
A fuel dispenser is a machine at a filling station that is used to pump gasoline, diesel, ethanol fuel, kerosene, or other types of fuel into vehicles. Fuel dispensers are also known as bowsers (in Australia).Petrol pumps (in Commonwealth countries), or gas pumps (in North America).
History
The first gasoline pump was invented and sold by Sylvanus F. Bowser in Fort Wayne, Indiana on September 5, 1885.[2] This pump was not used for automobiles, as they had not been invented yet. It was instead used for some kerosene lamps and stoves. He later improved upon the pump by adding safety measures, and also by adding a hose to directly dispense fuel into automobiles. For a while, the term bowser was used to refer to a vertical gasoline pump. Although the term is not used anymore in the United States, it still is used sometimes in Australia and New Zealand.
Many early gasoline pumps had a calibrated glass cylinder on top. The desired quantity of fuel was pumped up into the cylinder as indicated by the calibration. Then the pumping was stopped and the gasoline was let out into the customers tank by gravity. When metering pumps came into use, a small glass globe with a turbine inside replaced the measuring cylinder but assured the customer that gasoline really was flowing into the tank.
Design
A modern fuel dispenser is logically divided into 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, the mechanical section which in a ‘self contained’ unit has an electric motor, pumping unit, meters, pulsers and valves to physically pump and control the fuel flow.
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. In general submersible solutions in Europe are installed in hotter countries, where suction pumps may have problems overcoming cavitation with warm fuels or when the distance from tank to pump is longer than a suction pump can manage.
In modern pumps, the major variations are in the number of hoses or grades they can dispense, the physical shape, and the addition of extra devices such as pay at the pump devices and attendant "tag" readers.
Flow rate is typically 40+ litres per minute and is higher for highspeed pumps serving trucks and other large vehichles. In the USA flow rate is limited to 10 gallons per minute (37.8 litres per minute)
Nozzles
Nozzles are attached to the pump via flexible hoses, allowing them to be placed into the vehicle's filling inlet. The hoses are robust to survive hardships such as being driven over, and are often attached using heavy spring or coil arrangements to provide additional strength.
The nozzles are usually color coded to indicate which grade of fuel they dispense, however the color coding differs between countries or even retailers. For example, a black handle in the UK indicates that the fuel dispensed is diesel. In the US, diesel pumps commonly use green hoses and green slipcovers over the nozzle.
Flow measurement
One of the most important functions for the pump is to accurately measure the amount of fuel pumped. Flow measurement is almost always done by a 4 stroke piston meter connected to an electronic encoder. In older gas pumps, the meter is physically coupled to reeled meters (moving wheels with numbers on the side), while newer pumps turn the meters movement into electrical pulses using a rotary encoder.
Communications components
The technology for communicating with gas pumps from a point of sale or other controller varies widely, involving a variety of hardware (RS-485, RS-422, current loop, and others) and proprietary software protocols. Traditionally these variations gave pump manufacturers a natural tie-in for their own point-of-sale systems, since only they understood the protocols.
An effort to standardize this in the 1990s resulted in the International Forecourt Standards Forum, which has had considerable success in Europe
Automatic cut-off in fuel dispenser
The shut-off valve was invented in Olean, New York in 1939 by Richard C. Corson. At a loading dock at the Socony-Vacuum Oil Company, Corson observed a worker filling a barrel with gasoline and thought it inefficient. The sound of a toilet flushing later gave him the idea for a "butterfly float." After developing a prototype with his assistant, Paul Wenke, Corson gave the suggestion to the company who later filed for a patent in his name. The initial intent of the device was to "allow a person to fill more than one barrel [of gasoline] at the same time." This mechanism eventually developed into the modern gasoline pump cut-off valve.[7]
Most modern pumps have an auto cut-off feature that stops the flow when the tank is full. This is done with a second tube, the sensing tube, that runs from just inside the mouth of the nozzle up to a Venturi pump in the pump handle. A mechanical valve in the pump handle detects this change of pressure and closes, preventing the flow of fuel.]
Other components
A modern fuel pump will often contain control equipment for the vapor recovery system, which prevents gasoline vapor from escaping to the air. in the UK for example any new forecourt with a predicted throughput in excess of 500 M3 per month is required to have active vapour recovery installed。
Regulations
Since fuel dispensers 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, such as Mexico，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. Measurement Canada is the federal agent responsible for pump regulations in Canada and stickers are displayed the pumps.
References：www.wikipedia.com