Fuel dispenser
Encyclopedia
A fuel dispenser is a machine at a filling station
Filling station
A filling station, also known as a fueling station, garage, gasbar , gas station , petrol bunk , petrol pump , petrol garage, petrol kiosk , petrol station "'servo"' in Australia or service station, is a facility which sells fuel and lubricants...

 that is used to pump
Pump
A pump is a device used to move fluids, such as liquids, gases or slurries.A pump displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps...

 gasoline
Gasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...

, diesel, CNG
Compressed natural gas
Compressed natural gas is a fossil fuel substitute for gasoline , diesel, or propane/LPG. Although its combustion does produce greenhouse gases, it is a more environmentally clean alternative to those fuels, and it is much safer than other fuels in the event of a spill...

, CGH2, HCNG
HCNG
HCNG is a mixture of compressed natural gas and 4–9 percent hydrogen by energy. It may be used as a fuel gas for internal combustion engines and home appliances...

, LPG, LH2, ethanol fuel
Ethanol fuel
Ethanol fuel is ethanol , the same type of alcohol found in alcoholic beverages. It is most often used as a motor fuel, mainly as a biofuel additive for gasoline. World ethanol production for transport fuel tripled between 2000 and 2007 from 17 billion to more than 52 billion litres...

, biofuel
Biofuel
Biofuel is a type of fuel whose energy is derived from biological carbon fixation. Biofuels include fuels derived from biomass conversion, as well as solid biomass, liquid fuels and various biogases...

s like biodiesel
Biodiesel
Biodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl esters. Biodiesel is typically made by chemically reacting lipids with an alcohol....

, kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...

, or other types of fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...

 into vehicles. Fuel dispensers are also known as bowsers (in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

), petrol pumps (in Commonwealth
Commonwealth of Nations
The Commonwealth of Nations, normally referred to as the Commonwealth and formerly known as the British Commonwealth, is an intergovernmental organisation of fifty-four independent member states...

 countries), or gas pumps (in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

).

History

The first gasoline pump was invented and sold by Sylvanus F. Bowser in Fort Wayne, Indiana
Fort Wayne, Indiana
Fort Wayne is a city in the US state of Indiana and the county seat of Allen County. The population was 253,691 at the 2010 Census making it the 74th largest city in the United States and the second largest in Indiana...

 on September 5, 1885. This pump was not used for automobile
Automobile
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

s, 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
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, it still is used sometimes in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

.

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
Submersible pump
A submersible pump is a device which has a hermetically sealed motor close-coupled to the pump body. The whole assembly is submerged in the fluid to be pumped. The main advantage of this type of pump is that it prevents pump cavitation, a problem associated with a high elevation difference between...

. In general submersible solutions in Europe are installed in hotter countries, where suction pumps may have problems overcoming cavitation
Cavitation
Cavitation is the formation and then immediate implosion of cavities in a liquidi.e. small liquid-free zones that are the consequence of forces acting upon the liquid...

 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
Pay at the pump
Pay at the pump is a system used at some filling stations where customers can pay for their fuel by inserting a credit or debit card into a slot on the pump, bypassing the requirement to make the transaction with the station attendant or to walk away from one's vehicle.The system was introduced in...

 devices and attendant "tag" readers.

Flow rate is typically 40+ litres per minute and is higher for highspeed pumps serving trucks and other large vehicles. In the USA flow rate is limited to 10 gallon
Gallon
The gallon is a measure of volume. Historically it has had many different definitions, but there are three definitions in current use: the imperial gallon which is used in the United Kingdom and semi-officially within Canada, the United States liquid gallon and the lesser used United States dry...

s per minute (37.8 litres per minute).

Historically, fuel dispensers had a very wide range of designs to solve the mechanical problems of mechanical pumping, reliable measurement, safety, and aesthetics. This has led to some popularity in collecting antique dispensers, especially in the USA.

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.

Blending

In some countries, pumps are able to mix two grades of fuel together before dispensing; this is referred to as blending or mixing. Typical usages are in a "mix" pump to add oil to petrol for two-stroke
Two-stroke cycle
A two-stroke engine is an internal combustion engine that completes the process cycle in one revolution of the crankshaft...

 motorcycle
Motorcycle
A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...

s, to produce an intermediate octane rating
Octane rating
Octane rating or octane number is a standard measure of the anti-knock properties of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating...

 from separate high and low octane fuels, or to blend hydrogen and compressed natural gas
Compressed natural gas
Compressed natural gas is a fossil fuel substitute for gasoline , diesel, or propane/LPG. Although its combustion does produce greenhouse gases, it is a more environmentally clean alternative to those fuels, and it is much safer than other fuels in the event of a spill...

 (HCNG
HCNG
HCNG is a mixture of compressed natural gas and 4–9 percent hydrogen by energy. It may be used as a fuel gas for internal combustion engines and home appliances...

).

Flow measurement

One of the most important functions for the pump is to accurately measure the amount of fuel pumped. Flow measurement
Flow measurement
Flow measurement is the quantification of bulk fluid movement. Flow can be measured in a variety of ways.Positive-displacement flow meters acumulate a fixed volume of fluid and then count the number of times the volume is filled to measure flow...

 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
Rotary encoder
A rotary encoder, also called a shaft encoder, is an electro-mechanical device that converts the angular position or motion of a shaft or axle to an analog or digital code. The output of incremental encoders provides information about the motion of the shaft which is typically further processed...

.

The metrology of gasoline

Gasoline is difficult to sell in a fair and consistent manner by volumetric units. It expands and contracts significantly as its temperature changes. A comparison of the coefficient of thermal expansion for gasoline and water indicates that gasoline changes at about 4.5 times the rate of water.

In the United States, the National Institute of Standards and Technology
National Institute of Standards and Technology
The National Institute of Standards and Technology , known between 1901 and 1988 as the National Bureau of Standards , is a measurement standards laboratory, otherwise known as a National Metrological Institute , which is a non-regulatory agency of the United States Department of Commerce...

 (NIST) specifies the accuracy of the measurements in Handbook 44. Table 3.30 specifies the accuracy at 0.3% meaning that a 10 US gal (37.9 l; 8.3 imp gal) purchase could vary between 9.97 US gal (37.7 l; 8.3 imp gal) and 10.03 US gal (38 l; 8.4 imp gal) as to the actual amounts at the delivery temperature of the gasoline.

The reference temperature for gasoline volume measurement is 60 °F (15.6 °C). Ten gallons of gasoline at that temperature expands to about 10.05 US gal (38 l; 8.4 imp gal) at 85 °F (29.4 °C) and contracts to about 9.83 US gal (37.2 l; 8.2 imp gal) at 30 °F (-1.1 °C). Each of the three volumes represents the same theoretical amount of energy. In one sense, ten gallons of gasoline purchased at 30°F is about 3.2% more potential energy than ten gallons purchased at 85°F. Most gasoline is stored in tanks underneath the filling station
Filling station
A filling station, also known as a fueling station, garage, gasbar , gas station , petrol bunk , petrol pump , petrol garage, petrol kiosk , petrol station "'servo"' in Australia or service station, is a facility which sells fuel and lubricants...

. Modern tanks are non-metallic and sealed to stop leaks. Some have double walls or other structures that provide inadvertent thermal insulation while pursuing the main goal of keeping gasoline out of the soil around the tank. The net result is that while the air temperature can easily vary between 30°F and 85°F, the gasoline in the insulated tank changes temperature much more slowly.

Temperature compensation is common at the wholesale transaction level in the United States and most other countries. At the retail consumer level, Canada has converted to automatic temperature compensation and the United States has not. Where automatic temperature compensation is used, it can add up to 0.2% of uncertainty for mechanical-based compensation and 0.1% for electronic compensation, per Handbook 44.

There are many fewer retail outlets for gasoline in the United States today than there were in 1980. Larger outlets sell gasoline rapidly, as much as 30000 US gal (113,562.4 l; 24,980.2 imp gal) in a single day, even in remote places. Most finished product gasoline is delivered in 8 to 16 thousand gallon tank trucks so two deliveries in a 24 hour period is common. The belief is that the gasoline spends so little time in the retail sales system that its temperature at the point of sale does not vary significantly from winter to summer or by region. Canada has lower overall population densities and geographically larger gasoline distribution systems, compared to the United States. Temperature compensation at the retail level improves the fairness under those conditions.

Higher energy prices have raised awareness of this issue for consumers. At the same time, alternative fuel applications are now reaching the retail market and accurate comparisons between them in normal usage are needed. Eventually the basis for retail sales will change from volume units in liters or gallons to energy units such as the BTU, joule
Joule
The joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...

, therm
Therm
The therm is a non-SI unit of heat energy equal to 100,000 British thermal units . It is approximately the energy equivalent of burning 100 cubic feet of natural gas....

, or kWh so that electricity, liquids, liquefied gases and compressed gases can all be sold and taxed uniformly.

In some regions, regular required inspections are conducted to insure the accuracy of fuel dispensers. For example, in the US state of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, the Florida Department of Agriculture and Consumer Services
Florida Department of Agriculture and Consumer Services
The Florida Department of Agriculture and Consumer Services is an executive department of the government of Florida.The Commissioner of Agriculture is the head of the department...

 conducts regular tests of calibration and fuel quality at individual dispensers. The department also conducts random undercover inspections using specially designed vehicles that can check the accuracy of the dispensers. The department issues correction required notices to stations with pumps found to be inaccurate. Most other US states conduct similar inspections. In Canada, inspections are regularly conducted by the federal government department Measurement Canada
Measurement Canada
Measurement Canada is a Canadian government agency of Industry Canada whose mission is "to ensure equity and accuracy where goods and services are bought and sold on the basis of measurement, in order to contribute to a fair and competitive marketplace for Canadians." The agency is headed by a...

. Inspection dates and test results are required, by law, to be displayed on a sticker on fuel dispensers for consumers to see. Under a recently proposed legislation by the House of Commons (C-14: Fairness at the Pumps Act), fines for a vendor with a modified fuel dispenser or poorly maintained dispenser would be up to $50,000. However, virtually all pumps that fail inspection in Canada do so for general calibration errors caused by use over time. Intentional modification for the purpose of deceiving consumers is extremely rare.

Communications components

The technology for communicating with gas pumps from a point of sale
Point of sale
Point of sale or checkout is the location where a transaction occurs...

 or other controller varies widely, involving a variety of hardware (RS-485, RS-422, current loop
Current loop
A current loop describes two different electrical signalling schemes.- Digital :For digital serial communications, a current loop is a communication interface that uses current instead of voltage for signaling...

, 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
International Forecourt Standards Forum
The International Forecourt Standards Forum is a UK-based European organisation which designs standards for connecting devices on a service station forecourt, such as dispensers, Tank Level Gauges, Price Signs, Car Washes and Outdoor Payment Terminals...

, which has had considerable success in Europe, but has less presence elsewhere. ("Forecourt
Forecourt
In architecture a forecourt is an open area in front of a structure's entrance.In archaeology, forecourt is the name given to the area in front of certain types of chamber tomb...

" refers to the land area on which the fuel dispensers are located.)

Automatic cut-off in fuel dispenser

The shut-off valve was invented in Olean, New York
Olean, New York
Olean is a city in Cattaraugus County, New York, United States. Olean is the largest city in Cattaraugus County, and serves as the financial, business, transportation and entertainment center of the county. It is one of the principal cities of the Southern Tier region of New York.The city is...

 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.

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
Vapor recovery
Vapor recovery is the process of recovering the vapors of gasoline or other fuels, so that they do not escape into the atmosphere...

 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
Measurement Canada
Measurement Canada is a Canadian government agency of Industry Canada whose mission is "to ensure equity and accuracy where goods and services are bought and sold on the basis of measurement, in order to contribute to a fair and competitive marketplace for Canadians." The agency is headed by a...

 is the federal agent responsible for pump regulations in Canada and stickers are displayed on the pumps.

Unicode

Unicode 5.2 introduces the symbol ⛽ (U+26FD FUEL PUMP) to the Miscellaneous Symbols
Miscellaneous Symbols
The Miscellaneous Symbols Unicode block contains various glyphs representing things from a variety of categories: Astrological, Astronomical, Chess, Dice, Ideological symbols, Musical notation, Political symbols, Recycling, Religious symbols, Trigrams, Warning signs and Weather.-Tables:Note: These...

 set. It is representable in HTML as or .

See also

  • Fast fuel system
    Fast fuel system
    A Fast fuel system allows speedy refuelling of vehicles. Most large earthmoving and mining vehicles with diesel fuel tanks over are equipped with fast refueling systems. Fast refueling systems utilize an automatic shut off fuel nozzle, receiver and level control device...

  • Cascade storage system
  • HCNG dispenser
    HCNG dispenser
    A HCNG dispenser is a type of fuel dispenser at a filling station that is used to pump HCNG into vehicles.-Principle:A HCNG dispenser is in general combined with a CNG dispenser for natural gas vehicles as both use the same feed stream from the compressed natural gas grid, in addition the hydrogen...

  • Point of sale
    Point of sale
    Point of sale or checkout is the location where a transaction occurs...

     electronic system connected to fuel dispensers for processing sale transactions

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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