A gas tube or tank is a pressurized vessel used to store gas above atmospheric pressure. High pressure gas cylinders are also called bottles . Inside the cylinder, the stored gas may be in a liquid state, dissolved state, or compressed gas. Often, the gas cylinder extends and can stand upright on a flat bottom with a valve at the top.
Video Gas cylinder
Nomenklatur
In the United States, "gas bottles" usually refer to liquefied petroleum gas. "Bottled gas" is sometimes used in medical supplies, especially for portable oxygen tanks. Packaged industrial gases are often called "gas cylinders", although "bottled gas" is sometimes used.
The United Kingdom and other parts of Europe more often refer to "bottled gas" when discussing the use of anything whether industrial, medical, or liquid oil. However, on the contrary, what the United States calls liquid petroleum gas is known in general in the UK as "LPG"; and may be ordered by using one of several trade names, or specifically as butane or propane depending on the required heat output.
Maps Gas cylinder
History
With oil & amp; the price of petrochemical, transportation and storage of valuable gas translates into profitable profit margins and high value growth for the company. The adoption of gas cylinders continues to gain traction in such critical operations. Future Market Insights foresees strong growth for the global gas tube market in the coming years. According to a recent forecast study, the global gas cylinder market is expected to grow at a strong 8% CAGR in terms of value over the period, 2017-2026. Advanced safety features and effective storage capabilities of gas cylinders will play a key role in driving their sales during this assessment period. The report further projected that gas cylinders sold worldwide by the end of 2026 would generate revenues worth more than US $ 11 billion.
Materials
For a detailed discussion of the material for the gas cylinder see the pressure vessel.
Code design and standard applications along with material costs dictate a steel option without welding for most gas cylinders, are treated to be anti-corrosive. There are several new lightweight gas tubes developed from stainless steels and composite materials. Due to the high tensile strength of carbon fibers, these vessels can be very light, but much harder to make.
Cylinder rules and testing
Transport of high pressure cylinders is governed by many governments around the world. Various levels of testing are generally required by the regulating authority for the country in which it is to be transported. In the United States, this authority is the US Department of Transportation (DOT). Similarly in the UK, European transport regulations (ADRs) are implemented by the Department of Transport (DfT). For Canada, this authority is Transport Canada (TC). Cylinders may have additional requirements placed on the design and or performance of independent testing institutions such as Underwriter's Laboratory (UL). Each high pressure cylinder manufacturer is required to have an independent quality agent who will check the product for quality and safety.
In the UK, the " competent authority " Ã, - DfTÃ, - implements the rules and appointments of the official cylinder testers conducted by UKAS, which makes recommendations to the VCA for approval of each body.
There are various tests that can be performed on various cylinders. Some of the most common types of tests are hydrostatic test, crack test, tensile strength, Charpy impact test, and pressure cycling.
During the manufacturing process, important information is usually stamped or permanently marked on the cylinder. This information usually includes cylinder type, work pressure or service, serial number, manufacture date, manufactured code and sometimes test pressure. Other information may also be stamped depending on regulatory requirements.
High pressure cylinders are used several times - because most are - can be hydrostatically or ultrasonically tested and inspected visually every few years. In the United States, hydrostatic/ultrasonic testing is required every five years or every ten years, depending on the cylinder and its services. Helium gas cylinders have the highest pressure when full, about 1000 atmospheres.
Valve connection
The gas cylinder has a corner valve stopping at the tip above. During storage, transportation, and handling when the gas is not in use, the lid can be screwed over a protruding valve to protect it from damage or break if the cylinder falls. Instead of a cap, the cylinder generally has a protective collar or neck ring around the valve service assembly.
When the gas in the cylinder will be used at low pressure, the lid is removed and a pressure adjusting assembly is attached to the stop valve. This appendix usually has a pressure regulator with upstream pressure gauge (inlet) and downstream and downstream needle valves and a socket outlet connection. For gas that remains gas-shaped under ambient storage conditions, an upstream pressure gauge can be used to estimate how much gas is left in the cylinder according to pressure. For a liquid gas under storage, for example, propane, the outlet pressure depends on the vapor pressure of the gas, and does not fall until the cylinder is nearly depleted although it will vary according to the temperature of the cylinder contents. The regulator is adjusted to control the downstream pressure, which will limit the maximum flow of gas out of the cylinder at the pressure indicated by the downstream meter. The outlet connection is attached to anything that requires a gas supply, such as a balloon for example. For some purposes, such as welding, the regulator will also have a downstream flowmeter.
Valves in industrial, medical, and dive cylinders typically have different sizes and types, such as valves for different categories of gas, making it more difficult to misuse gas. For example, the hydrogen tube does not correspond to the oxygen supply line that will end in catastrophic failure. Some fittings use the right thread, while others use the left thread; Left threaded fittings can usually be identified with a grooved or indentation cut into it.
In the United States, valve connections are sometimes referred to as "CGA connections", because the Compressed Gas Association (CGA) publishes a guide on what connections are used for what products; eg, in the United States, the argon cylinder will have a CGA 580 connection on the valve.
Gas with high purity will sometimes use CGA-DISS connections ("System Safety Index Index").
The medical gas can use a pin-index system to prevent any gas connection to the service.
In the EU, DIN connections are more common than in the United States.
In the UK, the UK Standards Institute sets the standard. Included among the standards is the use of left threaded valves for flammable gas tubes (most commonly brass, BS4, valves for non-corrosive cylinders or stainless steels, BS15, valves for corrosive contents). The non combustible gas tube is equipped with a right threaded valve (most commonly brass, BS3, valve for non-corrosive component or stainless steel, BS14, valve for corrosive component).
Safety and standards
Because the contents are under pressure and sometimes hazardous materials, bottled gas handling is regulated. Regulations may include chaining bottles to prevent falling and damaging valves, proper ventilation to prevent injury or death in case of leaks and signs to indicate potential hazards If the end of the compressed gas cylinder ends, causing the valve block to be cut off, rapid release of high pressure gas may cause the cylinder accelerated greatly, potentially causing property damage, injury, or death. To prevent this, the cylinder is usually secured to a fixed object or a transport cart with a strap or chain.
In a fire, the pressure in the gas cylinder rises in proportion to its temperature. If the internal pressure exceeds the mechanical limitations of the cylinder and there is no means to vent the pressurized gas safely into the atmosphere, the ship will fail mechanically. If the contents of the vessel are flammable, the event can produce a "fireball". Oxidizers such as oxygen and fluorine will produce the same effect by accelerating combustion in the affected area. If the contents of the liquid cylinder, but into a gas at ambient conditions, this is usually referred to as a boiling liquid liquid explosion (BLEVE).
The medical gas tubes in the UK and some other countries have Wood metal plugs in the valve block between the valve seat and the cylinder. This plug melts at a relatively low temperature (70 ° C) and allows the contents of the cylinder to escape to the environment before the cylinder is significantly attenuated by heat, reducing the risk of explosion.
A more common pressure relief device is a simple spray disk mounted at the base of the valve between the cylinder and the valve seat. Exploding discs are small metal gaskets that are engineered to rupture at prescribed pressures. Some exploded discs are supported with low melting point metal, so the valve has to be exposed to excessive heat before the ruptured discs can break.
The Compressed Gas Association publishes a number of booklets and pamphlets on safe handling and use of bottled gas.
International and national standards
There are various standards relating to the manufacture, use and testing of pressure gas cylinders and related components. Some examples are listed here.
- ISO 11439: Gas cylinder - High-pressure tube for natural gas storage as automotive fuel vehicle
- ISO 15500-5: Vehicle - Components of compressed natural gas fuel system (CNG) - Part 5: Manual cylinder valve
- US DOT 3/4/8 ???: e-CFR (Federal Regulatory Electronic Code) Title 49, Section 178, Sub-Section C - Specification for Cylinders
- US DOT Aluminum Tank Alloy 6351-T6 amendment for SCUBA, SCBA, Oxygen Service - Visual Eddy Inspection
- US 2896-2011: Medical gas systems - Installation and testing of non-flammable medical gas pipelines (Australian Standard) pipelines.
Color coding
Gas cylinders are often color-coded, but they are not standardized in various jurisdictions, and sometimes unregulated. Unsafe cylinder color is used for positive product identification; The cylinder has a label to identify the gas it contains.
Common cylinder size
In scuba diving, the United States measures the volume of a cylinder with the amount of free air that can be compressed into a cylinder; Europe and most other worlds measure cylinder volume as an internal cylinder volume: eg. United States 19 cubic feet = Europe 3 liters at 180 bar.
Below is a sample cylinder size and is not an industry standard.
See also
- Bottled gas
- Press vessel
- Carbon fiber
- Composite overwrapped pressure vessel
- Fill carousel
- Industrial gas
- Storage tank
- UN Recommendation on Transport of Dangerous Goods
References
External links
- NASA - Safety Standards for Handling Oxygen and Oxygen
Source of the article : Wikipedia
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