A gas cabinet is a metallic enclosure which is used to provide local exhaust ventilation system for virtually all of the gases used or generated in the semiconductor, solar, MEMS, NANO, solar PV, manufacturing and other advanced technologies. [1]
The primary purpose of gas cabinets is to contain potential leaks in piping and fittings at the cylinder connection. The cabinet must be exhausted by a specifically designed fan and exhaust system. The cabinet exhaust system draws leaking hazardous gasses out of the cabinet. In the case of a flammable gas the cabinet will contain the flame for a period of time. [2] One can use a newly reconditioned cabinet as well as non-reconditioned used gas cabinets depending on their requirements. [3]
There are a variety of gas cabinets available in the market in different gas cylinder configurations, such as 1, 2 and 3 bottle designs. They can be either new, used, or reconditioned. A gas cylinder cabinet can have many features depending on the specific gas. These features include gas sensor, sprinkler head, excess flow sensor, automatic operation with automatic purging and excess pressure sensor.[ citation needed ]
They should meet the Uniform Fire Code Specifications and the National Fire Protection Association. They need to adhere to the Compressed Gas Association and Semiconductor Equipment & Materials Institute codes. It is also important to know whether the cabinet is OSHA compliant. OSHA offers additional safety precautions involving the use of gas cabinets. In the absence of finite specifications or unknowns the user or designer should seek the assistance of an impartial consultant. [4]
Reconditioned gas cabinets can be more useful than non-reconditioned used gas cabinets because of the thorough process used in professionally reconditioning and testing to ensure all systems meet manufacturer’s specifications. Different types of gas cabinets can be used, depending on the gas type in the cylinder. Automatic gas cabinets with multiple sensors are useful and fulfill many other requirements.
A gas cabinet can also be manufactured specifically for a company's needs and at lower cost. It is required that a gas cabinet is used for fire safety for gas cylinders. The requirements vary by state. Many states have no advanced regulations for hazardous industrial gasses since there is little or no use of such gasses in that state. [5]
The gas cabinets are categorized into four popular types based on the type of gas. [6] The categories are:
These gas cabinets are used for inert, non-reactive and non-toxic gases. There are automatic gas cabinets also available and thus these cabinets are less useful when compared to automatic cabinets.
These cabinets are available for corrosive, toxic and reactive gases. They provide safe and clean delivery of ultra-high purity gases. Such systems are designed to monitor a huge number of facility inputs and process sensors as per requirements.
These gas cabinets are useful when uninterrupted gas flow is required. Auto changeover gas cabinets can be defined by mass or pressure inputs. There is software also available for multiple cylinder scales on each joint or bank. Purge down and purge up processes can also be performed without any interruption of connected cylinders.[ citation needed ]
The port and valve specifications for gas cabinets and distribution systems are an important part of the selection process.
Gas cabinets may be distinguished by the types of valves used to control flow. Manual valves. Valves are manually adjusted or deployed via a control knob, lever, or other manual device. Solenoid valves. Valves are opened and closed via a solenoid magnet deployed by an electrical signal. Air pilot valves. Valves are deployed via a pneumatic signal.
Ports are openings in the manifold or distribution system where the inlet and outlet connections are produced. Each opening is either an inlet (supply) port or an outlet port. The number of each corresponds to the requirements of the application. The quantity of supply ports specifies the number of independent fluid supplies that could be interfaced with the manifold or manifold system.
The number of outlet ports establishes the number of outlets in the system. This is frequently specified as number of ports or valves that are or can be attached to the manifold. For example, an 8-point manifold has 8 ports or valves. Ports are sized based roughly on tube or pipe size with some important choices. For industrial gases it is possible to purchase manifolds made of Stainless steel pipe or copper and brass although both these materials are giving way to Stainless steel tubing. (Note differences between Tubing and Pipe). Connection choices might be NPT, VCO, Flare or other types.
For gas service that is "Clean For Oxygen Service (CFOS)" or for Ultra Pure service, manifolds and change over assemblies are typically made from 1/4" OD, 316 L, Electropolished tubing (the ID is Electropolished). The fittings used for ports and other connections are exclusively the "VCR" fitting. Training is needed to properly handle and install VCR connections using a variety of non-resuseable crushable metal gasket materials. Metal gaskets are essential in order to achieve high helium leak ratings.
The specifications for a gas cabinet detail everything from gas flow rates to the physical size of the system.[ citation needed ]
Pressure describes the amount of force exerted on a system by the contained and pressurized gas. Most compressed gases will not exceed 2,000 to 2,640 pounds per square inch gage (psig), but some can reach pressures of 6,000 psig. The system's weakest point determines the pressure limit, so any parts weakened by heat, corrosion, or stress may potentially lower the maximum pressure of the system or cause the vessel to rupture. Many times this is at the point of welds.[ citation needed ]
Flow rate details the maximum rate of flow of the gas through the operation, typically measured in standard cubic feet per minute (scfm).
Temperature range is the full mandated range of safe ambient or fluid operating temperatures, given in degrees Fahrenheit or degrees Celsius.
Size dimensions specify the physical size of the gas cabinet, distribution system, or its components. Cabinet size - Indicates the physical size of the gas cabinet or the body of the distribution system. Port/tube size - Indicates the physical size of the tubing or exhaust port connections in the system, typically given in inches based on a sizing standard such as National Pipe Thread (NPT). Sizing is important, as an undersized tube line will result in high pressure drops, while an oversized line will be unnecessarily expensive to install.
The materials used to construct the gas cabinet are an important part of proper system selection. The materials used for the casing and outer parts must have adequate structural strength, while the materials for the gas handling components must be compatible with the media, temperature requirements, and pressure ratings to prevent leakage, rupture, or contamination.
A light and fairly corrosion resistant metal which is most often anodized for increased corrosion and wear resistance. Aluminum is never used for tubing or fittings in modern industrial gas control & distribution systems since 316L stainless steel (optimum choice) is so available. Aluminum is not an ideal choice for purity. Aluminum in any form is never used for ultra pure industrial gas systems.
A soft, ductile metal with low hardness and excellent corrosion resistance. Copper is used commonly in tubes and pipes for its inertness and resistance to corrosion. Copper can be used for low air, oxygen and other inert non-critical gases such as medical CFOS systems. For ultra pure gasses 316L Stainless steel remains the optimum choice for many reasons.
Any of numerous thermoplastic or thermosetting polymers of high molecular weight. Different grades (such as nylon, acetal, and polycarbonate) have varying properties, but most have strong chemical and corrosion resistance.
General purpose industrial metal with high physical strength and hardness. Steel is typically coated or finished to increase its corrosion resistance properties. Steel is used in the petroleum and petro-chemical industries.
316L Stainless steel became industry standard for fittings, piping and controls in gas cabinets and distribution systems in the early 1980s. The material is further improved by electropolishing to render wetted surfaces extremely impervious to the most reactive gasses creating a non-shedding surface. A large industry has grown around supplying these ultra-specialized components and materials.
A valve is a device or natural object that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically fittings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure. The word is derived from the Latin valva, the moving part of a door, in turn from volvere, to turn, roll.
A diving cylinder or diving gas cylinder is a gas cylinder used to store and transport high pressure gas used in diving operations. This may be breathing gas used with a scuba set, in which case the cylinder may also be referred to as a scuba cylinder, scuba tank or diving tank. When used for an emergency gas supply for surface supplied diving or scuba, it may be referred to as a bailout cylinder or bailout bottle. It may also be used for surface-supplied diving or as decompression gas. A diving cylinder may also be used to supply inflation gas for a dry suit or buoyancy compensator. Cylinders provide gas to the diver through the demand valve of a diving regulator or the breathing loop of a diving rebreather.
A diving regulator or underwater diving regulator is a pressure regulator that controls the pressure of breathing gas for underwater diving. The most commonly recognised application is to reduce pressurized breathing gas to ambient pressure and deliver it to the diver, but there are also other types of gas pressure regulator used for diving applications. The gas may be air or one of a variety of specially blended breathing gases. The gas may be supplied from a scuba cylinder carried by the diver, in which case it is called a scuba regulator, or via a hose from a compressor or high-pressure storage cylinders at the surface in surface-supplied diving. A gas pressure regulator has one or more valves in series which reduce pressure from the source, and use the downstream pressure as feedback to control the delivered pressure, or the upstream pressure as feedback to prevent excessive flow rates, lowering the pressure at each stage.
The GM Ecotec engine, also known by its codename L850, is a family of all-aluminium inline-four engines, displacing between 1.4 and 2.5 litres. Confusingly, the Ecotec name was also applied to both the Buick V6 Engine when used in Holden Vehicles, as well as the final DOHC derivatives of the previous GM Family II engine; the architecture was substantially re-engineered for this new Ecotec application produced since 2000. This engine family replaced the GM Family II engine, the GM 122 engine, the Saab H engine, and the Quad 4 engine. It is manufactured in multiple locations, to include Spring Hill Manufacturing, in Spring Hill, Tennessee, with engine blocks and cylinder heads cast at Saginaw Metal Casting Operations in Saginaw, Michigan.
A hose is a flexible hollow tube designed to carry fluids from one location to another. Hoses are also sometimes called pipes, or more generally tubing. The shape of a hose is usually cylindrical.
In automotive engineering, an exhaust manifold collects the exhaust gases from multiple cylinders into one pipe. The word manifold comes from the Old English word manigfeald and refers to the folding together of multiple inputs and outputs.
Ultra-high vacuum is the vacuum regime characterised by pressures lower than about 1×10−6 pascals. UHV conditions are created by pumping the gas out of a UHV chamber. At these low pressures the mean free path of a gas molecule is greater than approximately 40 km, so the gas is in free molecular flow, and gas molecules will collide with the chamber walls many times before colliding with each other. Almost all molecular interactions therefore take place on various surfaces in the chamber.
A gas cylinder is a pressure vessel for storage and containment of gases at above atmospheric pressure. High-pressure gas cylinders are also called bottles. Inside the cylinder the stored contents may be in a state of compressed gas, vapor over liquid, supercritical fluid, or dissolved in a substrate material, depending on the physical characteristics of the contents. A typical gas cylinder design is elongated, standing upright on a flattened bottom end, with the valve and fitting at the top for connecting to the receiving apparatus.
An inlet manifold or intake manifold is the part of an internal combustion engine that supplies the fuel/air mixture to the cylinders. The word manifold comes from the Old English word manigfeald and refers to the multiplying of one (pipe) into many.
An exhaust system is used to guide reaction exhaust gases away from a controlled combustion inside an engine or stove. The entire system conveys burnt gases from the engine and includes one or more exhaust pipes. Depending on the overall system design, the exhaust gas may flow through one or more of the following:
A solenoid valve is an electromechanically operated valve.
A surface condenser is a water-cooled shell and tube heat exchanger installed to condense exhaust steam from a steam turbine in thermal power stations. These condensers are heat exchangers which convert steam from its gaseous to its liquid state at a pressure below atmospheric pressure. Where cooling water is in short supply, an air-cooled condenser is often used. An air-cooled condenser is however, significantly more expensive and cannot achieve as low a steam turbine exhaust pressure as a water-cooled surface condenser.
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases (fluids), slurries, powders and masses of small solids. It can also be used for structural applications; hollow pipe is far stiffer per unit weight than solid members.
The SAE steel grades system is a standard alloy numbering system for steel grades maintained by SAE International.
A scuba manifold is a device incorporating one or more valves and one or more gas outlets with scuba regulator connections, used to connect two or more diving cylinders containing breathing gas, providing a greater amount of gas for longer dive times or deeper dives. An isolation manifold allows the connection between the cylinders to be closed in the case of a leak from one of the cylinders or its valve or regulator, conserving the gas in the other cylinder. Diving with two or more cylinders is often associated with technical diving. Almost all manifold assemblies include one cylinder valve for each cylinder, and the overwhelming majority are for two cylinders.
The Mitsubishi 4B1 engine is a range of all-alloy straight-4 piston engines built at Mitsubishi's Japanese "World Engine" powertrain plant in Shiga on the basis of the Global Engine Manufacturing Alliance (GEMA). Although the basic designs of the various engines are the same, their exact specifications are individually tailored for each partner. The cylinder block and other basic structural parts of the engine were jointly developed by the GEMA companies, but the intake and exhaust manifolds, the cylinder head's intake and exhaust ports, and other elements related to engine tuning were independently developed by Mitsubishi.
A fitting or adapter is used in pipe systems to connect sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating fluid flow. These fittings are used in plumbing to manipulate the conveyance of fluids such as water for potatory, irrigational, sanitary, and refrigerative purposes, gas, petroleum, liquid waste, or any other liquid or gaseous substances required in domestic or commercial environments, within a system of pipes or tubes, connected by various methods, as dictated by the material of which these are made, the material being conveyed, and the particular environmental context in which they will be used, such as soldering, mortaring, caulking, Plastic welding, welding, friction fittings, threaded fittings, and compression fittings.
Orbital welding is a specialized area of welding whereby the arc is rotated mechanically through 360° around a static workpiece, an object such as a pipe, in a continuous process. The process was developed to address the issue of operator error in gas tungsten arc welding processes (GTAW), to support uniform welding around a pipe that would be significantly more difficult using a manual welding process, and to ensure high quality repeatable welds that would meet more stringent weld criteria set by ASME. In orbital welding, computer-controlled process runs with little intervention from the operator.
Corrosion monitoring is the use of a corrator or set of methods and equipment to provide offline or online information about corrosion rate expressed in mpy. - for better care and to take or improve preventive measures to combat and protect against corrosion. In this article, the difference between corrosion monitoring and corrosion protection, its difference with corrosion inspection and also the relationship between them, as well as online corrosion monitoring methods, equipment used and applications of each of them, are presented.
The mechanism of diving regulators is the arrangement of components and function of gas pressure regulators used in the systems which supply breathing gases for underwater diving. Both free-flow and demand regulators use mechanical feedback of the downstream pressure to control the opening of a valve which controls gas flow from the upstream, high-pressure side, to the downstream, low-pressure side of each stage. Flow capacity must be sufficient to allow the downstream pressure to be maintained at maximum demand, and sensitivity must be appropriate to deliver maximum required flow rate with a small variation in downstream pressure, and for a large variation in supply pressure, without instability of flow. Open circuit scuba regulators must also deliver against a variable ambient pressure. They must be robust and reliable, as they are life-support equipment which must function in the relatively hostile seawater environment, and the human interface must be comfortable over periods of several hours.