An automated tank cleaning machine is a machine used to clean cargo tanks such as those found in tank truck

Tank truck

A tank truck or road tanker is a motor vehicle designed to carry liquefied loads, dry bulk cargo or gases on roads. The largest such vehicles are similar to railroad tank cars which are also designed to carry liquefied loads...

s, railroad car

Railroad car

A railroad car or railway vehicle , also known as a bogie in Indian English, is a vehicle on a rail transport system that is used for the carrying of cargo or passengers. Cars can be coupled together into a train and hauled by one or more locomotives...

s, barge

Barge

A barge is a flat-bottomed boat, built mainly for river and canal transport of heavy goods. Some barges are not self-propelled and need to be towed by tugboats or pushed by towboats...

s, and oil tanker

Oil tanker

An oil tanker, also known as a petroleum tanker, is a merchant ship designed for the bulk transport of oil. There are two basic types of oil tankers: the crude tanker and the product tanker. Crude tankers move large quantities of unrefined crude oil from its point of extraction to refineries...

s. Genericized trademark

Genericized trademark

A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...

s such as Butterworth machine and Gamajet are often used to refer to automatic tank cleaning machines regardless of their manufacturer.

Operation

Tanks must be cleaned from time to time for various reasons. One reason is to change the type of product carried inside a tank. Another is to allow the tank to be inspected or for maintenance to be performed within a tank.

Automated tank cleaning machines work in a manner similar to an irrigation sprinkler

Irrigation sprinkler

Irrigation sprinklers are sprinklers used on farms, golf courses, and yards, to provide water to vegetation and plants in the event of drought. They may also be used for recreation, as a cooling system, or to keep down the amount of airborne dust....

. Hot water forced through a jet nozzle rotates the nozzle. The nozzle's rotation moves the machine through a cleaning pattern. As the water sprays, the liquid is pumped out of the tank. Portable water washing systems are widely used, but tanks that are cleaned frequently may have a fixed system installed.

The Butterworth Type K machine is widely used. This model can clean a tank of up to 10000000 gallons (37,854.1 m³). It uses water with a pressure up to 250 pound per square inches (1,723,689.3 Pa) and a temperature of up to 250 °F (121.1 °C). The water jet reaches up to 115 feet (35.1 m). Depending on the pressure used, a cleaning cycle can take from about 10 to 50 minutes and the machine uses between 15 US gal (56.8 l; 12.5 imp gal) and 350 US gal (1,324.9 l; 291.4 imp gal) per minute.

On most crude-oil tankers, a special crude oil washing system, or COW system, is part of the cleaning process. The COW system circulates hot crude oil through the fixed tank-cleaning system to remove wax and asphaltic deposits.

Although machines are often used to wash tanks, a final stage of manual cleaning known as mucking, is usually performed. Mucking requires protocols for entry into confined spaces and the use of airline respirator

Respirator

A respirator is a device designed to protect the wearer from inhaling harmful dusts, fumes, vapors, or gases. Respirators come in a wide range of types and sizes used by the military, private industry, and the public...

s, protective clothing and safety observers.

Tank cleaning is dangerous in a number of ways. While tank barges can be cleaned in port, shipboard tanks are generally cleaned at sea. This is largely due to risks of fire and explosion inside the tanks.

History

The first automated tank cleaning machine was invented by Arthur Butterworth and patented in 1920. His goal was to limit the amount of time that workers had to spend inside tanks, and partially relieve them of a dangerous and laborious job. In 1925, Butterworth established a company to market the machine. Standard Oil New Jersey bought the company in 1930, and it later became a subsidiary of the Exxon Corporation.

In 1986, as part of an internal restructuring at Exxon, the Butterworth company was sold to Exxon management. Today the company is privately held, and headquartered in Houston, Texas

Houston, Texas

Houston is the fourth-largest city in the United States, and the largest city in the state of Texas. According to the 2010 U.S. Census, the city had a population of 2.1 million people within an area of . Houston is the seat of Harris County and the economic center of , which is the ...

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